JP2022097072A - Recording material detector and image forming apparatus - Google Patents

Recording material detector and image forming apparatus Download PDF

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JP2022097072A
JP2022097072A JP2020210445A JP2020210445A JP2022097072A JP 2022097072 A JP2022097072 A JP 2022097072A JP 2020210445 A JP2020210445 A JP 2020210445A JP 2020210445 A JP2020210445 A JP 2020210445A JP 2022097072 A JP2022097072 A JP 2022097072A
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recording material
reception
signal
wave
value
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まゆみ 酒井
Mayumi Sakai
昌文 門出
Masafumi Monde
博光 熊田
Hiromitsu Kumada
純弥 阿左見
Junya Asami
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Canon Inc
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Canon Inc
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Priority to CN202111528864.7A priority patent/CN114646686A/en
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Abstract

To solve the problem in which: when a basis weight is detected by using the reception level of the same wave output from reception detection means regardless of the presence or absence of a recording material, increasing the amplification factor of a received signal increases the signal-to-noise ratio of the received signal.SOLUTION: A recording material detector comprises basis weight detection means that detects information on the basis weight of a recording material according to information on the amplitude of a first wave output from reception detection means in a period in which when the recording material is in an ultrasonic wave sensor, a wave with an amplitude less than a first value is output from the reception detection means, the period from when a driving input is input to sending means until when a second time elapses after the lapse of a first time, and information on the amplitude of a second wave output from the reception detection means in a period in which when the recording material is not in the ultrasonic wave sensor, a wave with an amplitude less than the first value is output from the reception detection means, the period from when the driving input is input to the sending means until when a fourth time elapses after the lapse of a third time. The first time is shorter than the third time.SELECTED DRAWING: Figure 2

Description

本発明は、超音波を用いた記録材の坪量の検知に関する。 The present invention relates to detecting the basis weight of a recording material using ultrasonic waves.

画像形成装置においては、サイズ、坪量、表面性など様々な特徴を備えた記録材に画像が形成される。特許文献1には、これらの記録材に応じた画像形成を行うため、画像形成装置内部に記録材の種類(以下、紙種と称す)を判別するための記録材判別装置を備えている。この記録材検知装置は、例えば、超音波を発信する発信手段と超音波を受信する受信手段とが、記録材が搬送される搬送路を挟むように設けられている。この発信手段が記録材に向けて超音波を発信し、記録材を介した超音波の受信レベルを用いて紙種を判別する方法が提案されている。 In the image forming apparatus, an image is formed on a recording material having various features such as size, basis weight, and surface properties. Patent Document 1 includes a recording material discriminating device for discriminating the type of recording material (hereinafter referred to as paper type) inside the image forming apparatus in order to form an image according to these recording materials. In this recording material detection device, for example, a transmitting means for transmitting ultrasonic waves and a receiving means for receiving ultrasonic waves are provided so as to sandwich a transport path through which the recording material is conveyed. A method has been proposed in which this transmitting means transmits ultrasonic waves toward the recording material and discriminates the paper type using the reception level of the ultrasonic waves through the recording material.

また、特許文献2には、記録材の紙種の判別を行うために、超音波の受信手段に到達する受信信号を測定することで、坪量の検知を行い、紙種の判別精度を向上させる方法が提案されている。この方法においては、記録材を介した超音波を受信手段によって受信した場合の受信レベルは、記録材を介していない超音波を受信手段によって受信した場合の受信レベルよりも小さい。このため、記録材を介した超音波を受信手段によって受信した場合の受信レベルの増幅率を、記録材を介していない超音波を受信手段によって受信した場合の受信レベルの増幅率に比べて大きくしている。 Further, in Patent Document 2, in order to discriminate the paper type of the recording material, the basis weight is detected by measuring the received signal reaching the ultrasonic wave receiving means, and the discriminating accuracy of the paper type is improved. A method to make it is proposed. In this method, the reception level when the ultrasonic wave through the recording material is received by the receiving means is smaller than the reception level when the ultrasonic wave not passing through the recording material is received by the receiving means. Therefore, the amplification factor of the reception level when the ultrasonic wave through the recording material is received by the receiving means is larger than the amplification factor of the reception level when the ultrasonic wave not passing through the recording material is received by the receiving means. is doing.

特開2004-219856JP-A-2004-219856 特開2009-292549JP-A-2009-292549

従来、記録材の有無に関わらず受信検知手段により出力される同じ波の受信レベルを用いて坪量に関する情報を検知することが知られており、記録材を介した超音波を受信する場合に受信信号の増幅率を大きくすることがある。しかしながら、受信信号の増幅率を大きくする場合、超音波を受信する回路に存在するノイズまでも増幅することとなる。 Conventionally, it has been known to detect information on the basis weight using the reception level of the same wave output by the reception detection means regardless of the presence or absence of the recording material, and when receiving ultrasonic waves through the recording material. The amplification factor of the received signal may be increased. However, when the amplification factor of the received signal is increased, even the noise existing in the circuit that receives the ultrasonic wave is amplified.

本出願に係る発明は、受信検知手段によって出力される波のうち記録材の有無に応じて記録材の坪量に関する情報を検知する際に用いる波を切り替えることにより、記録材の坪量に関する情報の検知精度の低下を抑制することを目的とする。 The invention according to the present application is to obtain information on the basis weight of the recording material by switching the wave used for detecting the information on the basis weight of the recording material depending on the presence or absence of the recording material among the waves output by the reception detection means. The purpose is to suppress the deterioration of the detection accuracy of.

上記課題を解決するために、本発明に関わる発明は、
超音波を発信する発信手段と、前記超音波を受信する受信手段と、を有し、前記発信手段と前記受信手段が、記録材が搬送される搬送路を挟むように設けられた超音波センサと、
前記発信手段に駆動入力を入力する指示手段と、
前記超音波センサにより受信した受信信号が入力され第1値以下の振幅の波を出力する受信検知手段と、
記録材を介していない超音波を前記受信手段により受信する場合、前記受信検知手段により前記第1値未満の振幅の波が出力される期間であって、前記発信手段に駆動入力が入力されてから第1の時間が経過した後且つ第2の時間が経過するまでの期間に前記受信検知手段により出力された第1の波の振幅情報と、記録材を介した超音波を前記受信手段により受信する場合、前記受信検知手段により前記第1値未満の振幅の波が出力される期間であって、前記発信手段に駆動入力が入力されてから第3の時間が経過した後且つ第4の時間が経過するまでの期間に前記受信検知手段により出力された第2の波の振幅情報と、に応じて記録材の坪量に関する情報を検知する坪量検知手段と、を備え、
前記第1の時間は前記第3の時間よりも短いことを特徴とする。
In order to solve the above problems, the inventions related to the present invention are
An ultrasonic sensor having a transmitting means for transmitting ultrasonic waves and a receiving means for receiving the ultrasonic waves, and the transmitting means and the receiving means are provided so as to sandwich a transport path through which a recording material is conveyed. When,
An instruction means for inputting a drive input to the transmission means and
A reception detection means for inputting a reception signal received by the ultrasonic sensor and outputting a wave having an amplitude equal to or lower than the first value.
When the ultrasonic wave that does not pass through the recording material is received by the receiving means, the drive input is input to the transmitting means during the period during which the receiving detecting means outputs a wave having an amplitude less than the first value. The amplitude information of the first wave output by the reception detection means and the ultrasonic wave via the recording material are transmitted by the reception means during the period from the first time to the second time. In the case of reception, it is a period during which a wave having an amplitude less than the first value is output by the reception detecting means, and after a third time has elapsed from the input of the drive input to the transmitting means and the fourth. It is provided with the amplitude information of the second wave output by the reception detecting means in the period until the time elapses, and the basis weight detecting means for detecting the information about the basis weight of the recording material according to the amplitude information.
The first time is characterized by being shorter than the third time.

以上説明したように、本発明によれば、受信検知手段によって出力される波のうち記録材の有無に応じて記録材の坪量に関する情報を検知する際に用いる波を切り替えることにより、記録材の坪量に関する情報の検知精度の低下を抑制することができる。 As described above, according to the present invention, among the waves output by the reception detection means, the recording material is switched by switching the wave used for detecting the information regarding the basis weight of the recording material according to the presence or absence of the recording material. It is possible to suppress a decrease in the detection accuracy of information related to the basis weight.

実施例1に係る画像形成装置1の概略構成図である。It is a schematic block diagram of the image forming apparatus 1 which concerns on Example 1. FIG. 実施例1に係る記録材判別装置19の概略構成図である。It is a schematic block diagram of the recording material discrimination apparatus 19 which concerns on Example 1. FIG. 位置補正係数Tと記録材Pの坪量の値との関係をプロットして得た近似式を示すグラフである。6 is a graph showing an approximate expression obtained by plotting the relationship between the position correction coefficient T and the value of the basis weight of the recording material P. 実施例1に係る発信回路部22の出力波形、受信信号の波形とピーク検知信号、受信信号の増幅率、信号雑音比の関係の一例を示す図である。It is a figure which shows an example of the relationship of the output waveform of the transmission circuit part 22 which concerns on Example 1, the waveform of a received signal and a peak detection signal, the amplification factor of a received signal, and the signal noise ratio. 実施例1に係る記録材判別装置19が実行する記録材Pの坪量の検知値を算出する処理のフローチャートである。It is a flowchart of the process of calculating the detection value of the basis weight of the recording material P executed by the recording material discrimination apparatus 19 which concerns on Example 1. FIG. 実施例1に係る記録材判別装置19が実行する坪量の検知値を算出する処理に関わる信号の状態や電圧の状態等を示すタイムチャートである。6 is a time chart showing a signal state, a voltage state, and the like related to the process of calculating the detection value of the basis weight executed by the recording material discrimination device 19 according to the first embodiment. 実施例2に係る発信回路部22の出力波形と、受信信号の波形とピーク検知信号、受信信号の増幅率、信号雑音比の関係の一例を示す図である。It is a figure which shows an example of the relationship between the output waveform of the transmission circuit part 22 which concerns on Example 2, the waveform of a received signal and a peak detection signal, the amplification factor of a received signal, and the signal noise ratio. 実施例2に係る記録材判別装置19が実行する記録材Pの坪量の検知値を算出する処理のフローチャートである。It is a flowchart of the process of calculating the detection value of the basis weight of the recording material P executed by the recording material discrimination apparatus 19 which concerns on Example 2. FIG. 実施例2に係る記録材判別装置19が実行する坪量の検知値を算出する処理に関わる信号の状態や電圧の状態等を示すタイムチャートである。6 is a time chart showing a signal state, a voltage state, and the like related to the process of calculating the detection value of the basis weight executed by the recording material discrimination device 19 according to the second embodiment. 実施例2の変形例に係る記録材判別装置19の概略構成図である。It is a schematic block diagram of the recording material discriminating apparatus 19 which concerns on the modification of Example 2. FIG.

以下、図面を用いて本発明の実施形態について説明する。なお、以下の実施形態は特許請求の範囲の発明を限定するものではなく、また実施形態で説明されている特徴の組合せの全てが本発明の解決手段に必須のものとは限らない。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the following embodiments do not limit the invention within the scope of the claims, and not all combinations of features described in the embodiments are essential for the means for solving the present invention.

[画像形成装置]
図1は、画像形成装置1の概略構成図である。画像形成装置1は、中間転写方式を採用した電子写真方式のフルカラープリンタである。画像形成装置1は、イエロー、マゼンタ、シアン、ブラックの各色の画像を形成する4つの画像形成ステーションを備えている。これらの4つの画像形成ステーションは一定の間隔をおいて一列に配置されている。なお、以下の説明では、参照符号の末尾の英文字Y、M、C及びKは、それぞれ当該部材がイエロー(Y)、マゼンタ(M)、シアン(C)、ブラック(K)のトナー像の形成に関する部材であることを示している。以下の説明において色を区別する必要が無い場合には、末尾の英文字Y、M、C及びKを除いた参照符号を使用することもある。
[Image forming device]
FIG. 1 is a schematic configuration diagram of an image forming apparatus 1. The image forming apparatus 1 is an electrophotographic full-color printer that employs an intermediate transfer method. The image forming apparatus 1 includes four image forming stations for forming images of each color of yellow, magenta, cyan, and black. These four image forming stations are arranged in a row at regular intervals. In the following description, the English letters Y, M, C, and K at the end of the reference code are toner images of yellow (Y), magenta (M), cyan (C), and black (K), respectively. It shows that it is a member related to formation. When it is not necessary to distinguish colors in the following description, a reference code excluding the last alphabetic characters Y, M, C and K may be used.

給紙カセット2は、例えば紙である記録材Pを積載する。給紙カセット2に積載された記録材Pは、給紙ローラ3によって給紙される。給紙ローラ3によって給紙された記録材Pは、搬送ローラ対4や、レジストローラ対5により搬送される。レジストローラ対5の近傍には、記録材Pの有無を検知するためのレジセンサ6が配置されている。 The paper cassette 2 is loaded with, for example, a recording material P which is paper. The recording material P loaded on the paper cassette 2 is fed by the paper feed roller 3. The recording material P fed by the paper feed roller 3 is conveyed by the transfer roller pair 4 and the resist roller pair 5. A resist sensor 6 for detecting the presence or absence of the recording material P is arranged in the vicinity of the resist roller pair 5.

感光ドラム7は、アルミニウムのドラム状の基体上に感光層を有しており、駆動装置(不図示)によって図中矢印の方向に所定のプロセススピードで回転駆動される。なお、ここでいうプロセススピードは、感光ドラム7の周速度(表面移動速度)に相当する。帯電ローラ8は、感光ドラム7を一様に所定の電位に帯電する。レーザスキャナ9は、画像情報に対応したレーザ光を照射し、感光ドラム7の表面を露光する。これにより、感光ドラム7の表面に画像情報に応じた静電潜像が形成される。 The photosensitive drum 7 has a photosensitive layer on an aluminum drum-shaped substrate, and is rotationally driven at a predetermined process speed in the direction of an arrow in the figure by a driving device (not shown). The process speed referred to here corresponds to the peripheral speed (surface moving speed) of the photosensitive drum 7. The charging roller 8 uniformly charges the photosensitive drum 7 to a predetermined potential. The laser scanner 9 irradiates a laser beam corresponding to the image information to expose the surface of the photosensitive drum 7. As a result, an electrostatic latent image corresponding to the image information is formed on the surface of the photosensitive drum 7.

プロセスカートリッジ10は、現像ローラ11を備え、プロセスカートリッジ10に収容されたトナーを用いて現像ローラ11により感光ドラム7上に形成された静電潜像を現像する。一次転写ローラ12は、感光ドラム7上に形成した画像を中間転写ベルト13に一次転写する。中間転写ベルト13は、駆動ローラ14によって駆動される。 The process cartridge 10 includes a developing roller 11, and the toner contained in the process cartridge 10 is used to develop an electrostatic latent image formed on the photosensitive drum 7 by the developing roller 11. The primary transfer roller 12 primary transfers the image formed on the photosensitive drum 7 to the intermediate transfer belt 13. The intermediate transfer belt 13 is driven by a drive roller 14.

二次転写ローラ15は、中間転写ベルト13上に一次転写された画像を記録材Pに二次転写する。定着器16は、加熱及び加圧することで二次転写された画像を記録材Pに定着する。以上説明した、画像形成に関する感光ドラム7から定着器16が画像形成部17の一例の構成である。排紙ローラ18は、定着器16によって定着が行われた記録材Pを排紙トレイに排紙する。 The secondary transfer roller 15 secondarily transfers the image primary transferred on the intermediate transfer belt 13 to the recording material P. The fuser 16 fixes the second-transferred image to the recording material P by heating and pressurizing. The fixing device 16 from the photosensitive drum 7 related to image formation described above is an example of the image forming unit 17. The paper ejection roller 18 ejects the recording material P fixed by the fixing device 16 to the paper ejection tray.

坪量検知手段としての記録材検知装置19は、記録材Pの坪量に関する情報を検知する。以下、記録材Pの坪量に基づき、記録材Pの種類を判別する方法と画像形成条件(二次転写条件、定着条件)を制御する方法について説明する。一般的に記録材Pの坪量によって記録材Pの抵抗値が異なるため、坪量に応じてトナーを二次転写するための二次転写バイアスの印加などの二次転写条件を変更する必要がある。また、記録材Pの坪量によって記録材Pの熱容量が異なるため、坪量に応じてトナーを定着するための定着温度や定着時間、記録材Pの搬送速度などの定着条件を変更する必要がある。 The recording material detecting device 19 as a basis weight detecting means detects information regarding the basis weight of the recording material P. Hereinafter, a method of determining the type of the recording material P and a method of controlling the image forming conditions (secondary transfer condition, fixing condition) based on the basis weight of the recording material P will be described. Generally, the resistance value of the recording material P differs depending on the basis weight of the recording material P, so it is necessary to change the secondary transfer conditions such as application of the secondary transfer bias for secondary transfer of the toner according to the basis weight. be. Further, since the heat capacity of the recording material P differs depending on the basis weight of the recording material P, it is necessary to change the fixing conditions such as the fixing temperature and fixing time for fixing the toner and the transport speed of the recording material P according to the basis weight. be.

制御部20は、CPU等を備えたMPU、画像形成装置1を制御するのに必要なデータの演算や一時的な記憶等に使われるRAM、画像形成装置1を制御するプログラムや各種データを格納するROM等の記憶部からなる。制御部20は、記録材検知装置19による坪量に関する情報の検知値に基づき、記録材Pの種類を判別する。そして、記録材Pの種類に応じた画像形成条件を決定し、記録材Pの種類に応じた画像形成条件で画像形成装置1の動作させるように制御する。 The control unit 20 stores an MPU equipped with a CPU and the like, a RAM used for data calculation and temporary storage required to control the image forming apparatus 1, a program for controlling the image forming apparatus 1, and various data. It consists of a storage unit such as a ROM. The control unit 20 determines the type of the recording material P based on the detection value of the information regarding the basis weight by the recording material detecting device 19. Then, the image forming conditions according to the type of the recording material P are determined, and the image forming apparatus 1 is controlled to operate under the image forming conditions according to the type of the recording material P.

[記録材検知装置19]
図2は、記録材検知装置19に関するブロック図である。
[Recording material detection device 19]
FIG. 2 is a block diagram relating to the recording material detection device 19.

記録材判別装置19は、超音波センサ21および発信回路部22、受信検知部23によって構成され、制御部20により制御される。 The recording material discrimination device 19 is composed of an ultrasonic sensor 21, a transmission circuit unit 22, and a reception detection unit 23, and is controlled by the control unit 20.

超音波センサ21は超音波によって記録材Pの坪量を検知するセンサであり、超音波を発信する発信手段21aと、超音波を受信する受信手段21bによって構成される。なお、超音波センサ21は、超音波発信装置とも称する。 The ultrasonic sensor 21 is a sensor that detects the basis weight of the recording material P by ultrasonic waves, and is composed of a transmitting means 21a that transmits ultrasonic waves and a receiving means 21b that receives ultrasonic waves. The ultrasonic sensor 21 is also referred to as an ultrasonic transmitter.

制御部20は、記録材判別装置19を制御するための発信指示部20aと増幅率切替指示部20bと受信レベル検知部20cとピーク検出部20dの機能を有する。発信指示部20aは、記録材判別装置19に駆動信号を出力することにより、発信手段21aから出力される出力信号を制御する。また、発信指示部20aは、記録材判別装置19に供給する駆動電圧を切り替えることにより発信回路部22から出力される出力信号の振幅を切り替える。なお、発信指示部20aは、記録材の有無に応じて駆動信号の周波数や駆動電圧を切り替える駆動入力切替手段を有しても良い。しかし本実施例においては、記録材の有無によらず駆動電圧は一定であるものとする。このとき、発信指示部20aにより生成される駆動信号は、一定周期のパルス波のバースト信号であり、発信回路部22で任意の振幅に切り替えられた出力信号により、発信手段21aから超音波を発信させる。 The control unit 20 has the functions of a transmission instruction unit 20a, an amplification factor switching instruction unit 20b, a reception level detection unit 20c, and a peak detection unit 20d for controlling the recording material discrimination device 19. The transmission instruction unit 20a controls the output signal output from the transmission means 21a by outputting a drive signal to the recording material discrimination device 19. Further, the transmission instruction unit 20a switches the amplitude of the output signal output from the transmission circuit unit 22 by switching the drive voltage supplied to the recording material discrimination device 19. The transmission instruction unit 20a may have a drive input switching means for switching the frequency and drive voltage of the drive signal depending on the presence or absence of the recording material. However, in this embodiment, it is assumed that the drive voltage is constant regardless of the presence or absence of the recording material. At this time, the drive signal generated by the transmission instruction unit 20a is a burst signal of a pulse wave having a fixed period, and ultrasonic waves are transmitted from the transmission means 21a by the output signal switched to an arbitrary amplitude by the transmission circuit unit 22. Let me.

発信回路部22からの出力端は、発信手段21aのUSS端子に接続される。発信手段21aは発信回路部22からの出力に応じて、周波数40kHzの超音波を発信する。受信手段21bは、発信手段21aから発信された超音波を受信し、受信した超音波の振幅に応じた受信信号を受信検知部23に出力する。なお、本実施形態では超音波の周波数を40kHzとしたものの、記録材Pの坪量の特性値を検知できる周波数であればよく、素子の特性に応じて周波数を設定することができる。また、発信手段21aと受信手段21bは、記録材Pを介した超音波を受信できるように、各々記録材Pを搬送する搬送路の近傍に、搬送路を挟むように配置されている。 The output end from the transmission circuit unit 22 is connected to the USS terminal of the transmission means 21a. The transmitting means 21a transmits an ultrasonic wave having a frequency of 40 kHz according to the output from the transmitting circuit unit 22. The receiving means 21b receives the ultrasonic waves transmitted from the transmitting means 21a, and outputs a reception signal corresponding to the amplitude of the received ultrasonic waves to the reception detection unit 23. Although the frequency of the ultrasonic wave is set to 40 kHz in this embodiment, the frequency may be any frequency as long as it can detect the characteristic value of the basis weight of the recording material P, and the frequency can be set according to the characteristics of the element. Further, the transmitting means 21a and the receiving means 21b are arranged so as to sandwich the transport path in the vicinity of the transport path for transporting the recording material P so that the ultrasonic waves can be received via the recording material P.

なお、受信手段21bが記録材Pを介していない超音波を受信する場合に発信手段21aにより発信される超音波の振幅の最大振幅を第1の最大振幅とも称する。また、第1の最大振幅の超音波を発信させるために発信手段21aへ第1の出力信号を出力するための駆動電圧および駆動信号を第1の駆動入力とも称する。また、受信手段21bが記録材Pを介した超音波を受信する場合に発信手段21aにより発信される超音波の振幅の最大振幅を第2の最大振幅とも称する。また、第2の最大振幅の超音波を発信させるために発信手段21aへ第2の出力信号を出力するための駆動電圧および駆動信号を第2の駆動入力とも称する。 The maximum amplitude of the ultrasonic wave transmitted by the transmitting means 21a when the receiving means 21b receives the ultrasonic wave not passing through the recording material P is also referred to as a first maximum amplitude. Further, the drive voltage and the drive signal for outputting the first output signal to the transmission means 21a in order to transmit the ultrasonic wave having the first maximum amplitude are also referred to as the first drive input. Further, the maximum amplitude of the ultrasonic wave transmitted by the transmitting means 21a when the receiving means 21b receives the ultrasonic wave via the recording material P is also referred to as a second maximum amplitude. Further, the drive voltage and the drive signal for outputting the second output signal to the transmission means 21a in order to transmit the ultrasonic wave having the second maximum amplitude are also referred to as a second drive input.

受信検知部23は、記録材Pを介した超音波を受信手段21bにより受信した受信信号の振幅を増幅率切替指示部20bによって増幅させ、半波整流する機能を有する回路部である。なお、本実施例において、受信検知部23は受信検知手段とも称する。増幅率切替指示部20bは、記録材Pの有無に応じて受信信号の振幅の増幅率を切り替える。例えば、受信手段が記録材Pを介していない超音波を受信する場合、増幅率は1倍とし、検知信号は増幅されないまま受信レベル検知部20cに入力される。また、受信手段が記録材Pを介した超音波を受信する場合、予め設定した増幅率で受信信号を増幅し、増幅された検知信号が受信レベル検知部20cに入力される。 The reception detection unit 23 is a circuit unit having a function of amplifying the amplitude of the reception signal received by the reception means 21b from the ultrasonic wave via the recording material P by the amplification factor switching instruction unit 20b and performing half-wave rectification. In this embodiment, the reception detection unit 23 is also referred to as a reception detection means. The amplification factor switching instruction unit 20b switches the amplification factor of the amplitude of the received signal according to the presence or absence of the recording material P. For example, when the receiving means receives ultrasonic waves that do not pass through the recording material P, the amplification factor is set to 1 and the detection signal is input to the reception level detection unit 20c without being amplified. Further, when the receiving means receives the ultrasonic wave via the recording material P, the received signal is amplified by a preset amplification factor, and the amplified detection signal is input to the reception level detection unit 20c.

受信検知部23で生成された検知信号は、制御部20のADポートに入力され、受信レベル検知部20cによりアナログ信号からデジタル信号へ変換される。制御部20は、受信レベル検知部20cにより変換されたデジタル値に基づいて検知信号の波形を検知し、そのピーク値(最大値)を算出し、超音波の受信レベルとして算出する。また、ピーク検出部20dは、受信レベル検知部20cにより変換されたデジタル値に基づいて検知信号の波形を検知し、ピーク値を検知する波形を選択する。本実施例においては、受信手段が記録材Pを介していない超音波を受信する場合、検知信号の1波目を、ピーク値をピーク検知信号として検知する波形として選択する。また、受信手段が記録材を介した超音波を受信する場合、駆動信号を入力してからから所定時間後の波形を、ピーク値をピーク検知信号として検知する波形として選択する。 The detection signal generated by the reception detection unit 23 is input to the AD port of the control unit 20, and is converted from an analog signal to a digital signal by the reception level detection unit 20c. The control unit 20 detects the waveform of the detection signal based on the digital value converted by the reception level detection unit 20c, calculates the peak value (maximum value) thereof, and calculates it as the ultrasonic reception level. Further, the peak detection unit 20d detects the waveform of the detection signal based on the digital value converted by the reception level detection unit 20c, and selects the waveform for detecting the peak value. In this embodiment, when the receiving means receives the ultrasonic wave not passing through the recording material P, the first wave of the detection signal is selected as the waveform for detecting the peak value as the peak detection signal. Further, when the receiving means receives the ultrasonic wave via the recording material, the waveform after a predetermined time after the input of the drive signal is selected as the waveform for detecting the peak value as the peak detection signal.

なお、本実施例において、受信手段が記録材Pを介していない超音波を受信する場合、ピーク値をピーク検知信号として検知するための波形として、検知信号の1波目を選択する、としたが、必ずしも1波目でなくても良い。受信手段が記録材Pを介していない超音波を受信する場合、ピーク値をピーク検知信号として検知するために選択する波形としては、検知信号の受信レベルが飽和しておらずピーク値を検知できる波であれば、どの波を選択しても良い。なお、受信レベルが飽和するとは、受信検知部23が、入力された受信信号を検知し検知信号を出力する際に検知可能な検知信号の上限に到達することである。このとき、上限となる検知信号の値を第1値とも称する。第1値は、受信検知部23により出力される波の振幅の最大値であり、受信検知部23は、第1値以下の振幅の波の検知信号を出力する。また、本実施例において受信手段が記録材Pを介した超音波を受信する場合、ピーク値をピーク検知信号として検知するために選択する波形として、駆動信号を入力してから所定時間後の波形を選択する、とした。しかし、必ずしも所定時間後の波形でなくても良い。また、本実施例において、受信手段が記録材Pを介した超音波を受信する場合のピーク値は、受信手段が記録材Pを介していない超音波を受信する場合のピーク値よりも大きな値となればよく、手段はこれに限らない。なお、このときの所定時間については、製造工程において予め測定した発信手段21aと受信手段21bとの距離と、製造工程において予め超音波センサにより検知した超音波の音速との関係から計算した時間とする。また、本実施例では、受信レベルの算出に、受信検知部23により出力される検知信号のうちのピーク値を用いたが、実効値や平均値など、受信信号のレベルを判断できる特性値であればよい。なお、受信検知部23を受信検知手段とも称する。 In this embodiment, when the receiving means receives ultrasonic waves that do not pass through the recording material P, the first wave of the detection signal is selected as the waveform for detecting the peak value as the peak detection signal. However, it does not necessarily have to be the first wave. When the receiving means receives ultrasonic waves that do not pass through the recording material P, the waveform selected for detecting the peak value as the peak detection signal is that the reception level of the detection signal is not saturated and the peak value can be detected. Any wave may be selected as long as it is a wave. When the reception level is saturated, the reception detection unit 23 reaches the upper limit of the detection signal that can be detected when the input reception signal is detected and the detection signal is output. At this time, the value of the detection signal which is the upper limit is also referred to as the first value. The first value is the maximum value of the wave amplitude output by the reception detection unit 23, and the reception detection unit 23 outputs a wave detection signal having an amplitude equal to or lower than the first value. Further, in the present embodiment, when the receiving means receives the ultrasonic wave via the recording material P, the waveform selected for detecting the peak value as the peak detection signal is the waveform after a predetermined time from the input of the drive signal. Was selected. However, it does not necessarily have to be the waveform after a predetermined time. Further, in the present embodiment, the peak value when the receiving means receives the ultrasonic wave through the recording material P is larger than the peak value when the receiving means receives the ultrasonic wave not passing through the recording material P. However, the means are not limited to this. The predetermined time at this time is the time calculated from the relationship between the distance between the transmitting means 21a and the receiving means 21b measured in advance in the manufacturing process and the sound wave velocity of the ultrasonic wave previously detected by the ultrasonic sensor in the manufacturing process. do. Further, in this embodiment, the peak value of the detection signals output by the reception detection unit 23 is used for the calculation of the reception level, but the characteristic values such as the effective value and the average value that can determine the level of the reception signal can be used. All you need is. The reception detection unit 23 is also referred to as a reception detection means.

なお、本実施例においては、受信手段が記録材を介していない超音波を受信した場合の受信レベルをVa1、受信手段が記録材を介した超音波を受信した場合の受信レベルをVp3とする。また、制御部20は、受信レベルVa1、Vp3を用いて記録材Pの坪量の算出を行う。 In this embodiment, the reception level when the receiving means receives the ultrasonic wave not through the recording material is Va1, and the reception level when the receiving means receives the ultrasonic wave through the recording material is Vp3. .. Further, the control unit 20 calculates the basis weight of the recording material P using the reception levels Va1 and Vp3.

<受信手段21bと発信手段21aの位置ばらつきの補正>
次に、紙種判別を行うにあたり必要となる受信手段21bと発信手段21aの位置ばらつきの補正について説明する。
<Correction of positional variation between receiving means 21b and transmitting means 21a>
Next, the correction of the positional variation between the receiving means 21b and the transmitting means 21a, which is necessary for discriminating the paper type, will be described.

画像形成装置1の製造工程では、超音波センサ21の画像形成装置1への取り付け時において、検知対象である記録材Pに対する受信手段21bと発信手段21aの位置がばらつく場合がある。この位置のばらつきにより、超音波が受信手段21bに到達する時間が変化し、受信レベル検知部20cにより検知される受信レベルがピーク値となる時間も変化してしまう場合がある。このため、以降のような補正係数を算出することにより、位置のばらつきを補正して坪量を検知することができる。 In the manufacturing process of the image forming apparatus 1, when the ultrasonic sensor 21 is attached to the image forming apparatus 1, the positions of the receiving means 21b and the transmitting means 21a with respect to the recording material P to be detected may vary. Due to this variation in position, the time for the ultrasonic wave to reach the receiving means 21b changes, and the time for the reception level detected by the reception level detecting unit 20c to reach the peak value may also change. Therefore, by calculating the correction coefficient as described below, it is possible to correct the variation in position and detect the basis weight.

受信手段21bが記録材Pを介していない超音波を受信する場合、受信レベル検知部20cにより出力された受信レベルをVa1とする。また、受信手段21bが記録材Pを介した超音波を受信する場合、受信レベル検知部20cにより出力された受信レベルをVp3とする。受信レベルVa1と受信レベルVp3を用いて位置補正係数Tを算出する。なお、本実施例では、受信レベルVa1を第1の波の振幅情報、受信レベルVp3を第2の波の振幅情報とも称する。
T=Vp3/Va1 ・・・ (式1)
When the receiving means 21b receives ultrasonic waves that do not pass through the recording material P, the reception level output by the reception level detection unit 20c is set to Va1. Further, when the receiving means 21b receives the ultrasonic wave via the recording material P, the reception level output by the reception level detection unit 20c is set to Vp3. The position correction coefficient T is calculated using the reception level Va1 and the reception level Vp3. In this embodiment, the reception level Va1 is also referred to as the amplitude information of the first wave, and the reception level Vp3 is also referred to as the amplitude information of the second wave.
T = Vp3 / Va1 ... (Equation 1)

制御部20は、図4に示すような、位置補正係数Tと記録材Pの坪量の値との関係をプロットして得た近似式を示すグラフを用いて、坪量を算出する。そして、算出した坪量に基づいて記録材Pの紙種を判断し、記録材Pの種類に応じた画像形成条件を決定し、画像形成装置1の動作を制御する。ここでの近似式は、予め実際の坪量と補正係数Tとから求め、制御部20の不揮発性メモリに保存されている。本実施例では、近似式を用いたが、位置補正係数Tと記録材Pの坪量の値との関係を示す変換テーブルを用いても良い。 The control unit 20 calculates the basis weight using a graph showing an approximate formula obtained by plotting the relationship between the position correction coefficient T and the basis weight value of the recording material P as shown in FIG. Then, the paper type of the recording material P is determined based on the calculated basis weight, the image forming conditions according to the type of the recording material P are determined, and the operation of the image forming apparatus 1 is controlled. The approximate expression here is obtained in advance from the actual basis weight and the correction coefficient T, and is stored in the non-volatile memory of the control unit 20. In this embodiment, an approximate expression is used, but a conversion table showing the relationship between the position correction coefficient T and the value of the basis weight of the recording material P may be used.

<記録材Pによる超音波の減衰と紙種の判別方法>
以降で、記録材Pによって超音波が減衰されることについて説明する。記録材Pを透過する超音波の減衰量は記録材Pの坪量に比例して大きくなる。つまり、記録材Pの坪量が増えるほど超音波の減衰量は大きくなるため、受信レベルVp3の値が小さくなる。記録材Pが坪量の小さい薄紙である場合、超音波の減衰量は普通紙よりも少ないため、受信レベルVp3の値は普通紙よりも大きくなる。一方、記録材Pが坪量の大きい厚紙である場合、超音波の減衰量は普通紙よりも多いため、受信レベルVp3の値は普通紙よりも小さくなる。つまり、受信レベルVp3の値が大きくなる場合、位置補正係数Tの値も大きくなる。
<Attenuation of ultrasonic waves by recording material P and method of discriminating paper type>
Hereinafter, it will be described that the ultrasonic wave is attenuated by the recording material P. The amount of attenuation of the ultrasonic wave transmitted through the recording material P increases in proportion to the basis weight of the recording material P. That is, as the basis weight of the recording material P increases, the amount of ultrasonic wave attenuation increases, so that the value of the reception level Vp3 decreases. When the recording material P is thin paper having a small basis weight, the amount of ultrasonic wave attenuation is smaller than that of plain paper, so that the value of the reception level Vp3 is larger than that of plain paper. On the other hand, when the recording material P is thick paper having a large basis weight, the amount of ultrasonic wave attenuation is larger than that of plain paper, so that the value of the reception level Vp3 is smaller than that of plain paper. That is, when the value of the reception level Vp3 becomes large, the value of the position correction coefficient T also becomes large.

例えば、制御部20は、図3に示す近似線を用いて、位置補正係数Tの値に対応する坪量を求める。制御部20により求めた坪量が、任意の閾値よりも小さい場合、記録材Pの紙種を薄紙と判別する。また、制御部20により求めた坪量が、任意の閾値よりも大きい場合、記録材Pの紙種を厚紙と判別する。このときの任意の閾値とは、例えば、図3に示すように、坪量が59g/m以下の場合は薄紙、坪量が60g/m~90g/mの場合は普通紙、坪量が90g/mの場合は厚紙、というような値である。なお、紙種の判別方法についてはこれに限らず、坪量と紙種の関係をあらかじめ不揮発性メモリに記憶させ、その情報を用いても良い。 For example, the control unit 20 obtains the basis weight corresponding to the value of the position correction coefficient T by using the approximate line shown in FIG. When the basis weight obtained by the control unit 20 is smaller than an arbitrary threshold value, the paper type of the recording material P is determined to be thin paper. Further, when the basis weight obtained by the control unit 20 is larger than an arbitrary threshold value, the paper type of the recording material P is determined to be thick paper. The arbitrary threshold value at this time is, for example, as shown in FIG. 3, thin paper when the basis weight is 59 g / m 2 or less, and plain paper or tsubo when the basis weight is 60 g / m 2 to 90 g / m 2 . When the amount is 90 g / m 2 , it is a value such as thick paper. The method for determining the paper type is not limited to this, and the relationship between the basis weight and the paper type may be stored in the non-volatile memory in advance and the information may be used.

<記録材の有無に応じてピーク値を検出する波形を切り替える理由>
続いて、本実施例において記録材の有無に応じてピーク値を検出する波形を切り替える理由について説明する。
<Reason for switching the waveform that detects the peak value depending on the presence or absence of recording material>
Next, the reason for switching the waveform for detecting the peak value according to the presence or absence of the recording material in this embodiment will be described.

まず、受信手段が記録材を介していない超音波を受信する場合と受信手段が記録材を介した超音波を受信する場合とで、同じタイミングの波形のピーク値を検知する場合について、図4(a)を用いて説明する。図4(a)では、受信手段が記録材を介していない超音波を受信する場合と、記録材を介した超音波を受信する場合とで、ピーク検出部20dによりそれぞれの受信信号の3番目の波形のピーク値をピーク検知信号として選択する。このときの検知回路の増幅率の切り替えとその信号雑音比を示す。 First, FIG. 4 shows a case where the receiving means receives ultrasonic waves that do not pass through the recording material and a case where the receiving means receives ultrasonic waves that pass through the recording material and a case where the peak value of the waveform at the same timing is detected. This will be described with reference to (a). In FIG. 4A, there are cases where the receiving means receives ultrasonic waves that do not pass through the recording material and cases where the receiving means receives ultrasonic waves through the recording material, and the peak detection unit 20d is the third of the received signals. The peak value of the waveform of is selected as the peak detection signal. The switching of the amplification factor of the detection circuit at this time and the signal-to-noise ratio thereof are shown.

記録材を介していない超音波を受信する場合、図4(a)に示すように、検知信号の受信レベルVa3が飽和しないように出力電圧の振幅を決定する。本実施例においては、このときの増幅率を1倍とする。また、本実施例において、1倍とした増幅率を第1の増幅率とも称する。受信手段が記録材を介した超音波を受信する場合、記録材によって超音波が減衰するため受信信号が小さくなり、検知信号も小さくなってしまう。このため、図4(a)に示すように、受信信号の増幅率を、受信手段が記録材を介していない超音波を受信する場合の増幅率よりも大きく、且つ、検知信号の受信レベルVp3が飽和しないように、増幅率を決定する。本実施例においては、このときの増幅率を20倍とする。また、本実施例において、20倍とした増幅率を第3の増幅率とも称する。しかしこのとき、受信手段が記録材を介した超音波を受信する場合の受信信号を増幅すると、超音波を受信する回路に存在するノイズの信号(不図示)も増幅してしまう場合がある。このため、超音波の受信信号に対するノイズの信号の比である信号雑音比が大きくなってしまう。 When receiving ultrasonic waves that do not pass through the recording material, as shown in FIG. 4A, the amplitude of the output voltage is determined so that the reception level Va3 of the detection signal is not saturated. In this embodiment, the amplification factor at this time is set to 1 time. Further, in this embodiment, the amplification factor that is multiplied by 1 is also referred to as a first amplification factor. When the receiving means receives the ultrasonic wave through the recording material, the ultrasonic wave is attenuated by the recording material, so that the received signal becomes small and the detection signal also becomes small. Therefore, as shown in FIG. 4A, the amplification factor of the received signal is larger than the amplification factor when the receiving means receives ultrasonic waves that do not pass through the recording material, and the reception level of the detection signal is Vp3. Determine the amplification factor so that is not saturated. In this embodiment, the amplification factor at this time is set to 20 times. Further, in this embodiment, the amplification factor increased by 20 times is also referred to as a third amplification factor. However, at this time, if the receiving signal when the receiving means receives the ultrasonic wave through the recording material is amplified, the noise signal (not shown) existing in the circuit for receiving the ultrasonic wave may also be amplified. Therefore, the signal-to-noise ratio, which is the ratio of the noise signal to the ultrasonic reception signal, becomes large.

そこで、本実施例においては、受信手段が記録材を介していない超音波を受信する場合と受信手段が記録材を介した超音波を受信する場合とで、ピーク検出部20dにより異なるタイミングの波形のピーク値を検知する。以降で、本実施例におけるピーク検出波形の切り替えについて、図4(b)を用いて説明する。 Therefore, in this embodiment, there are waveforms at different timings depending on the peak detection unit 20d depending on whether the receiving means receives the ultrasonic waves that do not pass through the recording material or the receiving means receives the ultrasonic waves that pass through the recording material. Detects the peak value of. Hereinafter, switching of the peak detection waveform in this embodiment will be described with reference to FIG. 4 (b).

図4(b)では、受信手段が記録材を介していない超音波を受信する場合、例えば、受信信号のうち飽和していない1番目の波形のピーク値をピーク検知信号として選択する。また、受信手段が記録材を介した超音波を受信する場合、例えば、受信信号の3番目の波形のピーク値をピーク検知信号として選択する。このときの検知回路の増幅率の切替えとその信号雑音比について説明する。 In FIG. 4B, when the receiving means receives ultrasonic waves that do not pass through the recording material, for example, the peak value of the first unsaturated waveform of the received signals is selected as the peak detection signal. Further, when the receiving means receives the ultrasonic wave through the recording material, for example, the peak value of the third waveform of the received signal is selected as the peak detection signal. The switching of the amplification factor of the detection circuit at this time and the signal-to-noise ratio thereof will be described.

受信手段が記録材を介していない超音波を受信する場合、検知信号の受信レベルVa1が飽和しないように、出力信号の振幅を決定する。本実施形態において、受信手段が記録材を介していない超音波を受信する場合、受信信号の1波目の受信レベルVa1が飽和しないレベルまで出力信号の振幅を大きくする。本実施例においては駆動電圧を10Vとし、このときの受信信号の増幅率を1倍とする。また、本実施例において、1倍とした増幅率を第1の増幅率とも称する。なお、本実施例において、受信信号の1波目の受信レベルは、図4(a)の受信手段が記録材を介していない超音波を受信する場合のピーク検知信号の波形に示すように、3波目の受信レベルよりも小さい受信レベルとした。しかし、受信レベルの大小関係については必ずしもこの関係でなくても良い。 When the receiving means receives ultrasonic waves that do not pass through the recording material, the amplitude of the output signal is determined so that the reception level Va1 of the detection signal is not saturated. In the present embodiment, when the receiving means receives ultrasonic waves that do not pass through the recording material, the amplitude of the output signal is increased to a level at which the reception level Va1 of the first wave of the received signal is not saturated. In this embodiment, the drive voltage is 10 V, and the amplification factor of the received signal at this time is 1 times. Further, in this embodiment, the amplification factor that is multiplied by 1 is also referred to as a first amplification factor. In this embodiment, the reception level of the first wave of the received signal is as shown in the waveform of the peak detection signal when the receiving means of FIG. 4A receives the ultrasonic wave without passing through the recording material. The reception level was set to be smaller than the reception level of the third wave. However, the magnitude relationship of the reception level does not necessarily have to be this relationship.

続いて、受信手段が記録材を介した超音波を受信する場合、検知信号の受信レベルVp3が飽和しないように、受信手段が記録材を介した超音波を受信する場合の受信信号の増幅率を決定する。このとき、受信手段が記録材を介していない超音波を受信する場合に受信レベルのピーク値を検出する波形を3波目に変更する。記録材の有無に関わらず受信レベルVa1が飽和しない程度に出力信号の振幅を大きく設定した。本実施例においては駆動電圧を10Vとした。これに伴い、受信手段が記録材を介した超音波を受信する場合の受信信号の増幅率は、図4(a)の場合と比べて小さい10倍とすることができる。また、本実施例において、10倍とした増幅率を第2の増幅率とも称する。このように、図4(b)の場合、図4(a)の場合よりも受信信号の増幅率が小さく済むことによって、図4(a)の場合と比べて信号雑音比が大きくなることを抑制することができる。 Subsequently, when the receiving means receives the ultrasonic wave through the recording material, the amplification factor of the received signal when the receiving means receives the ultrasonic wave through the recording material so that the reception level Vp3 of the detection signal is not saturated. To determine. At this time, the waveform for detecting the peak value of the reception level when the receiving means receives the ultrasonic wave that does not pass through the recording material is changed to the third wave. The amplitude of the output signal was set so large that the reception level Va1 was not saturated regardless of the presence or absence of the recording material. In this embodiment, the drive voltage is set to 10V. Along with this, the amplification factor of the received signal when the receiving means receives the ultrasonic wave through the recording material can be 10 times smaller than that in the case of FIG. 4A. Further, in this embodiment, the amplification factor multiplied by 10 is also referred to as a second amplification factor. As described above, in the case of FIG. 4B, the amplification factor of the received signal is smaller than that in the case of FIG. 4A, so that the signal noise ratio becomes larger than that in the case of FIG. 4A. It can be suppressed.

なお、出力信号の振幅は、ピーク検出信号Va1が飽和しない範囲であれば、本実施例で記載した電圧値に限らない。また、受信信号の増幅率は、ピーク検出信号Vp3が飽和しない範囲であれば、本実施例で記載した増幅率に限らない。 The amplitude of the output signal is not limited to the voltage value described in this embodiment as long as the peak detection signal Va1 is not saturated. Further, the amplification factor of the received signal is not limited to the amplification factor described in this embodiment as long as the peak detection signal Vp3 is not saturated.

[記録材Pの有無に応じたピーク検出信号の切り替え]
以降で、ピーク検出部20dが記録材の有無に応じてピーク検出信号を切り替えることにより、受信手段が記録材Pを介した超音波を受信する場合の信号雑音比が大きくなることを抑制する方法について図4と図5を用いて説明する。図5は、記録材Pの坪量を算出する処理のフローチャートであり、図6(a)~(g)は、坪量を算出する処理に関わる信号の状態や電圧の状態等を示すタイムチャートである。
[Switching of peak detection signal according to the presence or absence of recording material P]
Hereinafter, a method of suppressing an increase in the signal-to-noise ratio when the receiving means receives ultrasonic waves via the recording material P by switching the peak detection signal according to the presence or absence of the recording material by the peak detection unit 20d. Will be described with reference to FIGS. 4 and 5. FIG. 5 is a flowchart of a process for calculating the basis weight of the recording material P, and FIGS. 6 (a) to 6 (g) are time charts showing a signal state, a voltage state, and the like related to the process of calculating the basis weight. Is.

S100において、制御部20は、印刷指示を受信することにより、給紙動作を開始させる。 In S100, the control unit 20 starts the paper feeding operation by receiving the print instruction.

S101において、制御部20は、図6(b)に示すように、ピーク検出部20dによるピーク検出信号の切り替え信号としてLow信号を出力する。 In S101, as shown in FIG. 6B, the control unit 20 outputs a Low signal as a switching signal of the peak detection signal by the peak detection unit 20d.

S102において、制御部20のうちの発信指示部20aは、図6(d)に示すように、発信回路部22により出力される駆動電圧を10Vに設定する。これにより、図6(c)に示すように増幅率切替指示部20bにより受信検知部における受信信号の増幅率を1倍に設定する。 In S102, the transmission instruction unit 20a of the control unit 20 sets the drive voltage output by the transmission circuit unit 22 to 10V, as shown in FIG. 6D. As a result, as shown in FIG. 6C, the amplification factor switching instruction unit 20b sets the amplification factor of the received signal in the reception detection unit to 1 times.

S103において、制御部20は、給紙動作が開始された後にまだ記録材Pが超音波センサ21に到達していないタイミングにおいて、下記の処理を実行する。すなわち、制御部20は、図6(a)に示すように、受信手段が記録材を介していない超音波を受信する場合の受信手段による超音波の受信レベルの測定を開始する。制御部20は、図6(e)に示すように、発信指示部20aから発信回路部22へ駆動信号としてHigh信号を出力する。発信回路部22は、発信指示部20aからの駆動信号に応じて、図6(f)に示すようにUSS端子へ10Vの電圧を入力する。このとき、発信回路部22からUSS端子へは、電源10Vのパルス波のバースト信号が入力される。なお、本実施例において駆動信号は、一例として周波数を40kHz、パルス数を2パルス、バースト信号の周期を10msecとしている。 In S103, the control unit 20 executes the following processing at a timing when the recording material P has not yet reached the ultrasonic sensor 21 after the paper feeding operation is started. That is, as shown in FIG. 6A, the control unit 20 starts measuring the ultrasonic wave reception level by the receiving means when the receiving means receives the ultrasonic waves that do not pass through the recording material. As shown in FIG. 6E, the control unit 20 outputs a High signal as a drive signal from the transmission instruction unit 20a to the transmission circuit unit 22. The transmission circuit unit 22 inputs a voltage of 10V to the USS terminal as shown in FIG. 6F in response to the drive signal from the transmission instruction unit 20a. At this time, the burst signal of the pulse wave of the power supply 10V is input from the transmission circuit unit 22 to the USS terminal. In this embodiment, as an example, the drive signal has a frequency of 40 kHz, a pulse number of 2 pulses, and a burst signal period of 10 msec.

S104において、制御部20は、検知信号のうちの1番目の波形Va1を検出し、そのピーク値を検知する。1番目の波形Va1のピーク値の検知について以下で説明する。受信検知部23は、発信手段21aに駆動信号が入力された後、受信手段21bにより出力される受信信号が入力される。そこで、受信検知部23は、駆動信号と同期させた所定時間T1が経過してから受信信号を検知信号として検知することを開始する。より詳細には、駆動信号と同期させた所定時間T1が経過してから検知信号が基準値(例えば0Vとする)を超えると検知信号の検知を開始し、検知信号が基準値に戻るまでの間、検知信号を検知する。本実施例において所定時間T1は、製造工程において予め測定した発信手段21aと受信手段21bとの距離と、製造工程において予め超音波センサにより検知した超音波の音速との関係から計算した時間とする。なお、所定時間T1を第1の時間とも称し、制御部20が検知信号の検知を開始し、検知信号が基準値に戻るまでの間を第2の時間とも称する。また、第1の時間から第2の時間までの期間を、受信検知手段が出力可能である波の振幅の最大値である第1値未満の振幅の波が出力される期間とする。このように制御部20は、前記発信手段に駆動入力が入力されてから所定時間T1が経過した後且つ第2の時間が経過するまでの期間に検知信号の検知を行い、受信レベルVa1を算出する。なお、本実施例において、1番目の波形Va1を第1の波とも称し、受信レベルVa1となる振幅に関する値を第1の波の振幅情報とも称する。このとき、受信検知部23により生成された検知信号は、受信手段により受信された超音波の受信信号に従い、発信手段21aの音波の周波数と同じ40kHzの半波毎にピーク値を持つ波形となる。また、受信信号の波形の個数は、駆動信号のパルス数が2パルスであっても、2を超える数となる。これは、発信手段21aあるいは受信手段21bによる残響があるためである。 In S104, the control unit 20 detects the first waveform Va1 of the detection signals and detects the peak value thereof. The detection of the peak value of the first waveform Va1 will be described below. After the drive signal is input to the transmission means 21a, the reception detection unit 23 inputs the reception signal output by the reception means 21b. Therefore, the reception detection unit 23 starts to detect the reception signal as a detection signal after the predetermined time T1 synchronized with the drive signal has elapsed. More specifically, when the detection signal exceeds the reference value (for example, 0V) after the predetermined time T1 synchronized with the drive signal has elapsed, the detection of the detection signal is started until the detection signal returns to the reference value. During that time, the detection signal is detected. In this embodiment, the predetermined time T1 is a time calculated from the relationship between the distance between the transmitting means 21a and the receiving means 21b measured in advance in the manufacturing process and the sound wave velocity of the ultrasonic wave previously detected by the ultrasonic sensor in the manufacturing process. .. The predetermined time T1 is also referred to as a first time, and the period from when the control unit 20 starts detecting the detection signal until the detection signal returns to the reference value is also referred to as a second time. Further, the period from the first time to the second time is defined as a period in which a wave having an amplitude less than the first value, which is the maximum value of the amplitude of the wave that can be output by the reception detecting means, is output. In this way, the control unit 20 detects the detection signal during the period from the input of the drive input to the transmission means to the elapse of the predetermined time T1 and the elapse of the second time, and calculates the reception level Va1. do. In this embodiment, the first waveform Va1 is also referred to as a first wave, and the value relating to the amplitude at which the reception level Va1 is obtained is also referred to as the amplitude information of the first wave. At this time, the detection signal generated by the reception detection unit 23 becomes a waveform having a peak value for each half wave of 40 kHz, which is the same as the frequency of the sound wave of the transmission means 21a, according to the reception signal of the ultrasonic wave received by the reception means. .. Further, the number of waveforms of the received signal exceeds 2 even if the number of pulses of the drive signal is 2 pulses. This is because there is reverberation by the transmitting means 21a or the receiving means 21b.

S105において、制御部20は、図6(b)に示すようにピーク検出部20dによるピーク検出信号の切り替え信号としてHigh信号を出力する。 In S105, the control unit 20 outputs a High signal as a switching signal of the peak detection signal by the peak detection unit 20d as shown in FIG. 6B.

S106において、制御部20のうちの発信指示部20aは、図6(d)に示すように、発信回路部22により出力される駆動電圧を10Vに設定する。これにより、図6(c)に示すように増幅率切替指示部20bにより受信検知部における受信信号の増幅率を10倍に設定する。 In S106, the transmission instruction unit 20a of the control unit 20 sets the drive voltage output by the transmission circuit unit 22 to 10V, as shown in FIG. 6D. As a result, as shown in FIG. 6C, the amplification factor switching instruction unit 20b sets the amplification factor of the received signal in the reception detection unit to 10 times.

S107において、制御部20は、記録材Pの先端がレジセンサ6に到達したか否かに応じて次の処理を実行する。記録材Pの先端がレジセンサ6に到達した場合、制御部20は処理をS108へ進める。 In S107, the control unit 20 executes the next process depending on whether or not the tip of the recording material P has reached the registration sensor 6. When the tip of the recording material P reaches the registration sensor 6, the control unit 20 advances the process to S108.

S108において、制御部20は、記録材Pの先端がレジセンサ6に到達してから超音波センサ21に到達するタイミングを検知する為に、パルスモータ(不図示)のステップ数Sのカウントを開始する。 In S108, the control unit 20 starts counting the number of steps S of the pulse motor (not shown) in order to detect the timing when the tip of the recording material P reaches the registration sensor 6 and then reaches the ultrasonic sensor 21. ..

S109において、制御部20は、ステップ数Sのカウント値が所定の値(100)に到達したか否かに応じて、処理をS110に進める。制御部20は、ステップ数Sのカウント値が所定の値(100)となったら、処理をS110に進める。 In S109, the control unit 20 advances the process to S110 depending on whether or not the count value of the number of steps S has reached a predetermined value (100). When the count value of the number of steps S reaches a predetermined value (100), the control unit 20 advances the process to S110.

S110において、制御部20は、図6(e)に示すように、発信指示部20aから発信回路部22へ駆動信号としてHigh信号を出力する。制御部20は、発信回路部22からの出力信号により超音波センサ21を駆動させ、受信手段21bが記録材Pを介した超音波を受信する場合の受信検知部23による受信信号の受信レベルの測定を開始する。発信回路部22は、発信指示部20aからの駆動信号に応じて、図6(f)に示すようにUSS端子へ10Vの電圧を入力する。 In S110, as shown in FIG. 6E, the control unit 20 outputs a High signal as a drive signal from the transmission instruction unit 20a to the transmission circuit unit 22. The control unit 20 drives the ultrasonic sensor 21 by the output signal from the transmission circuit unit 22, and the reception level of the reception signal by the reception detection unit 23 when the reception means 21b receives the ultrasonic wave via the recording material P. Start the measurement. The transmission circuit unit 22 inputs a voltage of 10V to the USS terminal as shown in FIG. 6F in response to the drive signal from the transmission instruction unit 20a.

S111において、制御部20は、検知信号のうちの3番目の波形Vp3を検出し、そのピーク値を検出する。3番目の波形Vp3のピーク値の検知について以下で説明する。受信検知部23は、発信手段21aに駆動信号が入力された後、受信手段21bにより出力される受信信号が入力される。そこで、受信検知部23は、受信手段が記録材を介していない超音波を受信する場合の検出波形Va1の検知時と同様に、駆動信号と同期させた所定時間T2が経過してから受信信号を検知信号として検知することを開始する。より詳細には、駆動信号と同期させた所定時間T2が経過してから検知信号が基準値(例えば0Vとする)を超えると検知信号の検知を開始し、検知信号が基準値に戻るまでの間、検知信号を検知する。本実施例において所定時間T2は、製造工程において予め測定した発信手段21aと受信手段21bとの距離と、製造工程において予め超音波センサにより検知した超音波の音速との関係から計算した時間とし、所定時間T1よりも長い時間とする。なお、所定時間T2を第3の時間とも称し、制御部20が検知信号の検知を開始し、検知信号が基準値に戻るまでの間を第4の時間とも称する。また、第1の時間から第2の時間までの期間を、受信検知手段が出力可能である波の振幅の最大値である第1値未満の振幅の波が出力される期間とする。このように制御部20は、前記発信手段に駆動入力が入力されてから所定時間T2が経過した後且つ第4の時間が経過するまでの期間に検知信号の検知を行い、受信レベルVp3を算出する。なお、本実施例において、3番目の波形Vp3を第2の波とも称し、受信レベルVp3となる振幅に関する値を第2の波の振幅情報とも称する。 In S111, the control unit 20 detects the third waveform Vp3 of the detection signals and detects the peak value thereof. The detection of the peak value of the third waveform Vp3 will be described below. After the drive signal is input to the transmission means 21a, the reception detection unit 23 inputs the reception signal output by the reception means 21b. Therefore, the reception detection unit 23 receives the reception signal after a predetermined time T2 synchronized with the drive signal has elapsed, as in the case of detecting the detection waveform Va1 when the reception means receives the ultrasonic wave not through the recording material. Is started to be detected as a detection signal. More specifically, when the detection signal exceeds the reference value (for example, 0V) after the predetermined time T2 synchronized with the drive signal has elapsed, the detection of the detection signal is started until the detection signal returns to the reference value. During that time, the detection signal is detected. In the present embodiment, the predetermined time T2 is a time calculated from the relationship between the distance between the transmitting means 21a and the receiving means 21b measured in advance in the manufacturing process and the sound velocity of the ultrasonic waves previously detected by the ultrasonic sensor in the manufacturing process. The predetermined time is longer than T1. The predetermined time T2 is also referred to as a third time, and the period from when the control unit 20 starts detecting the detection signal until the detection signal returns to the reference value is also referred to as a fourth time. Further, the period from the first time to the second time is defined as a period in which a wave having an amplitude less than the first value, which is the maximum value of the amplitude of the wave that can be output by the reception detecting means, is output. In this way, the control unit 20 detects the detection signal during the period from the input of the drive input to the transmission means to the elapse of the predetermined time T2 and the elapse of the fourth time, and calculates the reception level Vp3. do. In this embodiment, the third waveform Vp3 is also referred to as a second wave, and the value relating to the amplitude at which the reception level is Vp3 is also referred to as the amplitude information of the second wave.

S112において、制御部20は、受信レベルVa1とVp3を式(1)に代入して、位置補正係数Tを算出する。S111において、算出した位置補正係数Tと記憶部に保持していた近似式を用いて記録材Pの坪量を算出する。S113において、算出した坪量に応じて、画像形成条件を決定し、処理を終了する。なお、本実施例では、位置補正係数Tに基づいて坪量を算出しても良いし、位置補正係数Tに基づいて画像形成条件を変更しても良い。また、本実施例では、位置補正係数Tに基づいて紙種を判別しても良い。 In S112, the control unit 20 substitutes the reception levels Va1 and Vp3 into the equation (1) to calculate the position correction coefficient T. In S111, the basis weight of the recording material P is calculated using the calculated position correction coefficient T and the approximate expression held in the storage unit. In S113, the image formation conditions are determined according to the calculated basis weight, and the process is terminated. In this embodiment, the basis weight may be calculated based on the position correction coefficient T, or the image formation conditions may be changed based on the position correction coefficient T. Further, in this embodiment, the paper type may be determined based on the position correction coefficient T.

なお、本実施例においては、発信回路部22から出力される出力信号の振幅を切り替える駆動電圧を10Vとした。しかし駆動電圧は10Vに限らず、受信手段21bが記録材Pを介していない超音波を受信する場合に検知信号の受信レベルとして飽和しない値を検知できるのであれば、10V以上であっても良い。 In this embodiment, the drive voltage for switching the amplitude of the output signal output from the transmission circuit unit 22 is set to 10V. However, the drive voltage is not limited to 10V, and may be 10V or more as long as the receiving means 21b can detect a value that does not saturate as the reception level of the detection signal when receiving ultrasonic waves that do not pass through the recording material P. ..

このように、本実施例においては、ピーク検出部20dが記録材の有無に応じて、受信信号のうちピーク値を検知する波形を切り替える。すなわち、受信手段21bが記録材Pを介していない超音波を受信する場合、ピーク検出部20dにより例えば受信信号の1番目の波形のピーク値をピーク検知信号として選択する。また、受信手段21bが記録材Pを介した超音波を受信する場合、ピーク検出部20dにより例えば受信信号の3番目の波形のピーク値をピーク検知信号として選択する。このため、受信手段21bが記録材Pを介した超音波を受信する場合、超音波の受信信号の増幅率が大きくなることを抑制でき、超音波を受信する回路に存在するノイズが坪量の検知結果に及ぼす影響を低減することができる。 As described above, in this embodiment, the peak detection unit 20d switches the waveform for detecting the peak value among the received signals according to the presence or absence of the recording material. That is, when the receiving means 21b receives the ultrasonic wave that does not pass through the recording material P, the peak detection unit 20d selects, for example, the peak value of the first waveform of the received signal as the peak detection signal. Further, when the receiving means 21b receives the ultrasonic wave via the recording material P, the peak detection unit 20d selects, for example, the peak value of the third waveform of the received signal as the peak detection signal. Therefore, when the receiving means 21b receives the ultrasonic wave via the recording material P, it is possible to suppress an increase in the amplification factor of the ultrasonic wave reception signal, and the noise existing in the circuit for receiving the ultrasonic wave has a basis weight. The effect on the detection result can be reduced.

なお、本実施例において、ピーク検出部20dが記録材の有無に応じて、受信信号のうちピーク値を検知する波形を切り替える方法として、駆動信号と同期した所定時間の間の検知信号を検知する方法について記載した。しかし、ピーク値を検知する波形を切り替える方法としてはこれに限らない。例えば、ピーク値を検知する波形を切り替える方法としては、受信レベル検知部20cにより、受信検知部23で生成された検知信号から変換されたデジタル信号を用いて、検知信号の波形を検知し、波形をカウントする方法であっても良い。このとき、検知信号のデジタル信号が最大となり波形がピーク値となるポイントをカウントしても良いし、検知信号のデジタル信号が0の値となり波形が横軸と交わるポイントをカウントしても良い。 In this embodiment, the peak detection unit 20d detects the detection signal for a predetermined time synchronized with the drive signal as a method of switching the waveform for detecting the peak value among the received signals according to the presence or absence of the recording material. The method was described. However, the method of switching the waveform for detecting the peak value is not limited to this. For example, as a method of switching the waveform for detecting the peak value, the reception level detection unit 20c detects the waveform of the detection signal using the digital signal converted from the detection signal generated by the reception detection unit 23, and the waveform. It may be a method of counting. At this time, the point where the digital signal of the detection signal becomes the maximum and the waveform becomes the peak value may be counted, or the point where the digital signal of the detection signal becomes a value of 0 and the waveform intersects the horizontal axis may be counted.

また本実施例においては、ピーク値を検知する波形を切り替える方法として、以下のような方法であっても良い。例えば、製造工程において予め超音波センサにより検知信号を検知し、検知信号の受信レベルが飽和しない値に閾値Vthを設け、発信手段に駆動入力が入力されてから検知信号が閾値Vthを超えるまでの時間を検知する方法であっても良い。この場合、例えば、検知信号の受信レベルが飽和しない値、すなわち、受信信号が受信検知部23によって検知可能な信号の上限値よりも小さい値に、閾値としてVthを設ける。なお、閾値Vthを第2値とも称する。受信手段が記録材を介していない超音波を受信する場合、発信手段に駆動入力が入力されてから検知信号が閾値Vthの値以上となるまでの時間をTaとする。また、受信手段が記録材を介した超音波を受信する場合、発信手段に駆動入力が入力されてから検知信号が閾値Vthの値以上となるまでの時間をTpとする。このようにして得られたTaとTpに応じて、記録材Pの坪量を検知する方法であっても良い。なお、Taを第1の期間とも称し、Tpを第2の期間とも称する。 Further, in this embodiment, the following method may be used as a method for switching the waveform for detecting the peak value. For example, in the manufacturing process, a detection signal is detected in advance by an ultrasonic sensor, a threshold value Vth is set at a value at which the reception level of the detection signal is not saturated, and the detection signal exceeds the threshold value Vth after the drive input is input to the transmitting means. It may be a method of detecting time. In this case, for example, Vth is set as a threshold value at a value at which the reception level of the detection signal is not saturated, that is, a value at which the received signal is smaller than the upper limit value of the signal that can be detected by the reception detection unit 23. The threshold value Vth is also referred to as a second value. When the receiving means receives ultrasonic waves that do not pass through the recording material, the time from when the drive input is input to the transmitting means until the detection signal becomes equal to or higher than the threshold value Vth is defined as Ta. Further, when the receiving means receives the ultrasonic wave via the recording material, the time from the input of the drive input to the transmitting means until the detection signal becomes equal to or higher than the threshold value Vth is defined as Tp. A method of detecting the basis weight of the recording material P may be used according to the Ta and Tp thus obtained. In addition, Ta is also referred to as a first period, and Tp is also referred to as a second period.

実施例1において、超音波の受信信号の増幅率が大きくなることを抑制する方法として、下記の方法について説明した。すなわち、発信回路部22から出力される出力信号の振幅を切り替える駆動電圧を、記録材の有無によらず例えば10Vで一定とし、記録材Pの有無に応じてピーク値を検知する波形を切り替える方法について説明した。本実施例においては、記録材Pの有無に応じて出力信号の振幅の大きさを切り替え、且つ、ピーク値を検知する波形を切り替える方法について説明する。なお、実施例1と同一の構成に関しては、同一の番号を付与し説明を省略する。また、同じ符号の箇所については、同一の機能、動作を行うものとする。 In Example 1, the following method has been described as a method for suppressing an increase in the amplification factor of the ultrasonic wave reception signal. That is, a method in which the drive voltage for switching the amplitude of the output signal output from the transmission circuit unit 22 is constant at, for example, 10 V regardless of the presence or absence of the recording material, and the waveform for detecting the peak value is switched according to the presence or absence of the recording material P. Explained. In this embodiment, a method of switching the magnitude of the amplitude of the output signal according to the presence / absence of the recording material P and switching the waveform for detecting the peak value will be described. Regarding the same configuration as that of the first embodiment, the same number will be assigned and the description thereof will be omitted. In addition, the same functions and operations shall be performed for the parts with the same reference numerals.

まず、受信手段が記録材を介した超音波を受信する場合において、出力信号の振幅を大きくすることにより、受信信号の増幅率が大きくなることを抑制する。これにより、受信手段が記録材を介した超音波を受信する場合の検知信号の受信レベルVp3の信号雑音比が大きくなることを抑制する。以降で、本実施例におけるピーク検出波形の切り替えについて、図7を用いて説明する。 First, when the receiving means receives the ultrasonic wave through the recording material, the amplification factor of the received signal is suppressed from being increased by increasing the amplitude of the output signal. This suppresses an increase in the signal noise ratio of the reception level Vp3 of the detection signal when the receiving means receives the ultrasonic wave through the recording material. Hereinafter, switching of the peak detection waveform in this embodiment will be described with reference to FIG. 7.

図7では、図4(b)と同様に、受信手段が記録材を介していない超音波を受信する場合、例えば、受信信号の1番目の波形のピーク値をピーク検知信号として選択する。また、受信手段が記録材を介した超音波を受信する場合、例えば、受信信号の3番目の波形のピーク値をピーク検知信号として選択する。このときの検知回路の増幅率の切替えとその信号雑音比について説明する。 In FIG. 7, similarly to FIG. 4B, when the receiving means receives the ultrasonic wave without passing through the recording material, for example, the peak value of the first waveform of the received signal is selected as the peak detection signal. Further, when the receiving means receives the ultrasonic wave through the recording material, for example, the peak value of the third waveform of the received signal is selected as the peak detection signal. The switching of the amplification factor of the detection circuit at this time and the signal-to-noise ratio thereof will be described.

図7の受信手段が記録材を介していない超音波を受信する場合、については、図4(b)における説明と同様であるため説明を省略する。 The case where the receiving means of FIG. 7 receives the ultrasonic wave without passing through the recording material is the same as the description in FIG. 4B, and thus the description thereof will be omitted.

図7の受信手段が記録材を介した超音波を受信する場合、検知信号の受信レベルVp3が飽和しないように、出力信号の振幅と増幅率を決定する。本実施例においては、駆動入力切替手段により記録材の有無に応じて駆動電圧を切り替え、受信手段が記録材を介した超音波を受信する場合の駆動電圧を、例えば20Vとした。これにより、図4(b)の場合と比べて増幅率5倍に下げることができる。増幅率が小さく済むことにより、図4(b)の場合と比べて信号雑音比が大きくなることを抑制することができる。 When the receiving means of FIG. 7 receives the ultrasonic wave through the recording material, the amplitude and amplification factor of the output signal are determined so that the reception level Vp3 of the detection signal is not saturated. In this embodiment, the drive voltage is switched according to the presence or absence of the recording material by the drive input switching means, and the drive voltage when the receiving means receives the ultrasonic wave through the recording material is set to, for example, 20V. As a result, the amplification factor can be reduced to 5 times as compared with the case of FIG. 4 (b). By reducing the amplification factor, it is possible to suppress an increase in the signal-to-noise ratio as compared with the case of FIG. 4B.

なお、出力信号の振幅は、ピーク検出信号Va1が飽和しない範囲であれば、本実施例で記載した電圧値に限らない。また、受信信号の増幅率は、ピーク検出信号Vp3が飽和しない範囲であれば、本実施例で記載した増幅率に限らない。 The amplitude of the output signal is not limited to the voltage value described in this embodiment as long as the peak detection signal Va1 is not saturated. Further, the amplification factor of the received signal is not limited to the amplification factor described in this embodiment as long as the peak detection signal Vp3 is not saturated.

[記録材Pの有無に応じた出力信号とピーク検出信号の切り替え]
以降で、ピーク検出部20dが記録材の有無に応じて出力信号およびピーク検出信号を切り替えることにより、受信手段が記録材Pを介した超音波を受信する場合の受信レベルVpの信号雑音比が大きくなることを抑制する方法について説明する。図8は、記録材Pの坪量を算出する処理のフローチャートであり、図9(a)~(g)は、坪量を算出する処理に関わる信号の状態や電圧の状態等を示すタイムチャートである。図5および図6と同一の構成に関しては、同一の番号を付与し説明を省略する。同じ符号の箇所については、同一の機能、動作を行うため説明を省略する。
[Switching between output signal and peak detection signal according to the presence or absence of recording material P]
After that, the peak detection unit 20d switches between the output signal and the peak detection signal according to the presence or absence of the recording material, so that the signal noise ratio of the reception level Vp when the receiving means receives the ultrasonic wave through the recording material P is increased. A method of suppressing the growth will be described. FIG. 8 is a flowchart of a process for calculating the basis weight of the recording material P, and FIGS. 9 (a) to 9 (g) are time charts showing a signal state, a voltage state, and the like related to the process of calculating the basis weight. Is. The same configurations as those in FIGS. 5 and 6 are assigned the same numbers and the description thereof will be omitted. Since the parts having the same reference numerals have the same functions and operations, the description thereof will be omitted.

S101において、制御部20は、図9(b)に示すようにピーク検出部20dによるピーク検出信号の切り替え信号としてLow信号を出力する。 In S101, the control unit 20 outputs a Low signal as a switching signal of the peak detection signal by the peak detection unit 20d as shown in FIG. 9B.

S102において、制御部20のうちの発信指示部20aは、図9(d)に示すように、発信回路部22により出力される駆動電圧を10Vに設定する。これにより、図9(c)に示すように増幅率切替指示部20bにより受信検知部における受信信号の増幅率を1倍に設定する。 In S102, the transmission instruction unit 20a of the control unit 20 sets the drive voltage output by the transmission circuit unit 22 to 10V, as shown in FIG. 9D. As a result, as shown in FIG. 9C, the amplification factor switching instruction unit 20b sets the amplification factor of the received signal in the reception detection unit to 1 times.

S103において、制御部20は、給紙動作が開始された後にまだ記録材Pが超音波センサ21に到達していないタイミングにおいて、下記の処理を実行する。すなわち、制御部20は、図9(a)に示すように、受信手段が記録材を介していない超音波を受信する場合の受信手段による超音波の受信レベルの測定を開始する。制御部20は、図9(e)に示すように、発信指示部20aから発信回路部22へ駆動信号としてHigh信号を出力する。発信回路部22は、発信指示部20aからの駆動信号に応じて、図6(f)に示すようにUSS端子へ10Vの電圧を入力する。発信回路部22からUSS端子へは、電源10Vのパルス波のバースト信号が入力される。なお、本実施例において駆動信号は、一例として周波数を40kHz、パルス数を2パルス、バースト信号の周期を10msecとしている。 In S103, the control unit 20 executes the following processing at a timing when the recording material P has not yet reached the ultrasonic sensor 21 after the paper feeding operation is started. That is, as shown in FIG. 9A, the control unit 20 starts measuring the ultrasonic wave reception level by the receiving means when the receiving means receives the ultrasonic waves that do not pass through the recording material. As shown in FIG. 9E, the control unit 20 outputs a High signal as a drive signal from the transmission instruction unit 20a to the transmission circuit unit 22. The transmission circuit unit 22 inputs a voltage of 10V to the USS terminal as shown in FIG. 6F in response to the drive signal from the transmission instruction unit 20a. A burst signal of a pulse wave of a power supply of 10 V is input from the transmission circuit unit 22 to the USS terminal. In this embodiment, as an example, the drive signal has a frequency of 40 kHz, a pulse number of 2 pulses, and a burst signal period of 10 msec.

S104において、制御部20は、検知信号のうちの1番目の波形Va1を検出し、そのピーク値を検知する。1番目の波形Va1のピーク値の検知について以下で説明する。受信検知部23は、発信手段21aに駆動信号が入力された後、受信手段21bにより出力される受信信号が入力される。そこで、受信検知部23は、駆動信号と同期させた所定時間T1が経過してから受信信号を検知信号として検知することを開始する。より詳細には、駆動信号と同期させた所定時間T1が経過してから検知信号が基準値(例えば0Vとする)を超えると検知信号の検知を開始し、検知信号が基準値に戻るまでの間、検知信号を検知する。本実施例において所定時間T1は、製造工程において予め測定した発信手段21aと受信手段21bとの距離と、製造工程において予め超音波センサにより検知した超音波の音速との関係から計算した時間とする。なお、所定時間T1を第1の時間とも称し、制御部20が検知信号の検知を開始し、検知信号が基準値に戻るまでの間を第2の時間とも称する。また、第1の時間から第2の時間までの期間を、受信検知手段が出力可能である波の振幅の最大値である第1値未満の振幅の波が出力される期間とする。このように制御部20は、前記発信手段に駆動入力が入力されてから所定時間T1が経過した後且つ第2の時間が経過するまでの期間に検知信号の検知を行い、受信レベルVa1を算出する。なお、本実施例において、1番目の波形Va1を第1の波とも称し、受信レベルVa1となる振幅に関する値を第1の波の振幅情報とも称する。 In S104, the control unit 20 detects the first waveform Va1 of the detection signals and detects the peak value thereof. The detection of the peak value of the first waveform Va1 will be described below. After the drive signal is input to the transmission means 21a, the reception detection unit 23 inputs the reception signal output by the reception means 21b. Therefore, the reception detection unit 23 starts to detect the reception signal as a detection signal after the predetermined time T1 synchronized with the drive signal has elapsed. More specifically, when the detection signal exceeds the reference value (for example, 0V) after the predetermined time T1 synchronized with the drive signal has elapsed, the detection of the detection signal is started until the detection signal returns to the reference value. During that time, the detection signal is detected. In this embodiment, the predetermined time T1 is a time calculated from the relationship between the distance between the transmitting means 21a and the receiving means 21b measured in advance in the manufacturing process and the sound wave velocity of the ultrasonic wave previously detected by the ultrasonic sensor in the manufacturing process. .. The predetermined time T1 is also referred to as a first time, and the period from when the control unit 20 starts detecting the detection signal until the detection signal returns to the reference value is also referred to as a second time. Further, the period from the first time to the second time is defined as a period in which a wave having an amplitude less than the first value, which is the maximum value of the amplitude of the wave that can be output by the reception detecting means, is output. In this way, the control unit 20 detects the detection signal during the period from the input of the drive input to the transmission means to the elapse of the predetermined time T1 and the elapse of the second time, and calculates the reception level Va1. do. In this embodiment, the first waveform Va1 is also referred to as a first wave, and the value relating to the amplitude at which the reception level Va1 is obtained is also referred to as the amplitude information of the first wave.

S105において、制御部20は、図9(b)に示すようにピーク検出部20dによるピーク検出信号の切り替え信号としてHigh信号を出力する。 In S105, the control unit 20 outputs a High signal as a switching signal of the peak detection signal by the peak detection unit 20d as shown in FIG. 9B.

S201において、制御部20のうちの発信指示部20aは、図9(d)に示すように、発信回路部22により出力される駆動電圧を20Vに設定する。これにより、図9(c)に示すように増幅率切替指示部20bにより受信検知部における受信信号の増幅率を5倍に設定する。 In S201, the transmission instruction unit 20a of the control unit 20 sets the drive voltage output by the transmission circuit unit 22 to 20V, as shown in FIG. 9D. As a result, as shown in FIG. 9C, the amplification factor switching instruction unit 20b sets the amplification factor of the received signal in the reception detection unit to 5 times.

S107において、制御部20は、記録材Pの先端がレジセンサ6に到達したか否かに応じて次の処理を実行する。記録材Pの先端がレジセンサ6に到達した場合、制御部20は処理をS108へ進める。 In S107, the control unit 20 executes the next process depending on whether or not the tip of the recording material P has reached the registration sensor 6. When the tip of the recording material P reaches the registration sensor 6, the control unit 20 advances the process to S108.

S108において、制御部20は、記録材Pの先端がレジセンサ6に到達してから超音波センサ21に到達するタイミングを検知する為に、パルスモータ(不図示)のステップ数Sのカウントを開始する。 In S108, the control unit 20 starts counting the number of steps S of the pulse motor (not shown) in order to detect the timing when the tip of the recording material P reaches the registration sensor 6 and then reaches the ultrasonic sensor 21. ..

S109において、制御部20は、ステップ数Sのカウント値が所定の値(100)に到達したか否かに応じて、処理をS110に進める。制御部20は、ステップ数Sのカウント値が所定の値(100)となったら、処理をS110に進める。 In S109, the control unit 20 advances the process to S110 depending on whether or not the count value of the number of steps S has reached a predetermined value (100). When the count value of the number of steps S reaches a predetermined value (100), the control unit 20 advances the process to S110.

S203において、制御部20は、図9(e)に示すように、発信指示部20aから発信回路部22へ駆動信号としてHigh信号を出力する。制御部20は、発信回路部22からの出力信号により超音波センサ21を駆動させ、受信手段21bが記録材Pを介した超音波を受信する場合の受信検知部23による受信信号の受信レベルの測定を開始する。このとき、発信回路部22は、発信指示部20aからの駆動信号に応じて、図9(f)に示すようにUSS端子へ20Vの電圧を入力する。 In S203, as shown in FIG. 9E, the control unit 20 outputs a High signal as a drive signal from the transmission instruction unit 20a to the transmission circuit unit 22. The control unit 20 drives the ultrasonic sensor 21 by the output signal from the transmission circuit unit 22, and the reception level of the reception signal by the reception detection unit 23 when the reception means 21b receives the ultrasonic wave via the recording material P. Start the measurement. At this time, the transmission circuit unit 22 inputs a voltage of 20V to the USS terminal as shown in FIG. 9F in response to the drive signal from the transmission instruction unit 20a.

S111において、制御部20は、検知信号のうちの3番目の波形Vp3を検出し、そのピーク値を検出する。3番目の波形Vp3のピーク値の検出について以下で説明する。受信検知部23は、発信手段21aに駆動信号が入力された後、受信手段21bにより出力される受信信号が入力される。そこで、受信検知部23は、受信手段が記録材を介していない超音波を受信する場合の検出波形Va1の検知時と同様に、駆動信号と同期させた所定時間T2が経過してから受信信号を検知信号として検知することを開始する。より詳細には、駆動信号と同期させた所定時間T2が経過してから検知信号が基準値(例えば0Vとする)を超えると検知信号の検知を開始し、検知信号が基準値に戻るまでの間、検知信号を検知する。本実施例において所定時間T2は、製造工程において予め測定した発信手段21aと受信手段21bとの距離と、製造工程において予め超音波センサにより検知した超音波の音速との関係から計算した時間とし、所定時間T1よりも長い時間とする。なお、所定時間T2を第3の時間とも称し、制御部20が検知信号の検知を開始し、検知信号が基準値に戻るまでの間を第4の時間とも称する。また、第1の時間から第2の時間までの期間を、受信検知手段が出力可能である波の振幅の最大値である第1値未満の振幅の波が出力される期間とする。このように制御部20は、前記発信手段に駆動入力が入力されてから所定時間T2が経過した後且つ第4の時間が経過するまでの期間に検知信号の検知を行い、受信レベルVp3を算出する。なお、本実施例において、3番目の波形Vp3を第2の波とも称し、受信レベルVp3となる振幅に関する値を第2の波の振幅情報とも称する。 In S111, the control unit 20 detects the third waveform Vp3 of the detection signals and detects the peak value thereof. The detection of the peak value of the third waveform Vp3 will be described below. After the drive signal is input to the transmission means 21a, the reception detection unit 23 inputs the reception signal output by the reception means 21b. Therefore, the reception detection unit 23 receives the reception signal after a predetermined time T2 synchronized with the drive signal has elapsed, as in the case of detecting the detection waveform Va1 when the reception means receives the ultrasonic wave not through the recording material. Is started to be detected as a detection signal. More specifically, when the detection signal exceeds the reference value (for example, 0V) after the predetermined time T2 synchronized with the drive signal has elapsed, the detection of the detection signal is started until the detection signal returns to the reference value. During that time, the detection signal is detected. In the present embodiment, the predetermined time T2 is a time calculated from the relationship between the distance between the transmitting means 21a and the receiving means 21b measured in advance in the manufacturing process and the sound velocity of the ultrasonic waves previously detected by the ultrasonic sensor in the manufacturing process. The predetermined time is longer than T1. The predetermined time T2 is also referred to as a third time, and the period from when the control unit 20 starts detecting the detection signal until the detection signal returns to the reference value is also referred to as a fourth time. Further, the period from the first time to the second time is defined as a period in which a wave having an amplitude less than the first value, which is the maximum value of the amplitude of the wave that can be output by the reception detecting means, is output. In this way, the control unit 20 detects the detection signal during the period from the input of the drive input to the transmission means to the elapse of the predetermined time T2 and the elapse of the fourth time, and calculates the reception level Vp3. do. In this embodiment, the third waveform Vp3 is also referred to as a second wave, and the value relating to the amplitude at which the reception level is Vp3 is also referred to as the amplitude information of the second wave.

S112において、制御部20は、受信レベルVa1とVpを式(1)に代入して、位置補正係数Tを算出する。以降の処理は、図5と同一であるため、説明を省略する。 In S112, the control unit 20 substitutes the reception levels Va1 and Vp into the equation (1) to calculate the position correction coefficient T. Since the subsequent processing is the same as that in FIG. 5, the description thereof will be omitted.

なお、本実施例において、記録材Pの有無に応じて出力信号の振幅の大きさを切り替える際に、駆動電圧を切り替える方法を用いた。しかし、図10に示すように、制御部20が発信回路部22に入力された電圧の増幅率を制御するための増幅率切替指示部20eを有し、下記のような制御を実行しても良い。すなわち、駆動電圧は記録材Pの有無によらず一定とし、記録材の有無に応じて増幅率切替指示部20eからの増幅率切替信号を切り替え、発信回路部22に入力された電圧の増幅率を切り替えても良い。この場合、例えば、駆動電圧は記録材Pの有無によらず20Vとし、受信手段21bが記録材Pを介していない超音波を受信する場合、増幅率を1/2倍とする。また、受信手段21bが記録材Pを介した超音波を受信する場合、増幅率を1倍とする。 In this embodiment, a method of switching the drive voltage when switching the magnitude of the amplitude of the output signal depending on the presence or absence of the recording material P is used. However, as shown in FIG. 10, even if the control unit 20 has an amplification factor switching instruction unit 20e for controlling the amplification factor of the voltage input to the transmission circuit unit 22, the following control may be executed. good. That is, the drive voltage is constant regardless of the presence or absence of the recording material P, the amplification factor switching signal from the amplification factor switching instruction unit 20e is switched according to the presence or absence of the recording material, and the amplification factor of the voltage input to the transmission circuit unit 22. May be switched. In this case, for example, the drive voltage is set to 20 V regardless of the presence or absence of the recording material P, and when the receiving means 21b receives ultrasonic waves that do not pass through the recording material P, the amplification factor is halved. Further, when the receiving means 21b receives the ultrasonic wave via the recording material P, the amplification factor is set to 1 time.

このように、本実施例においては、記録材Pの有無に応じて出力信号の振幅の大きさを切り替え、且つ、ピーク検出部20dが記録材の有無に応じて、受信信号のうちピーク値を検知する波形を切り替える。すなわち、受信手段21bが記録材Pを介していない超音波を受信する場合、ピーク検出部20dにより例えば受信信号の1番目の波形のピーク値をピーク検知信号として選択する。また、受信手段21bが記録材Pを介した超音波を受信する場合、受信手段21bが記録材Pを介していない超音波を受信する場合よりも出力信号の振幅を大きくする。そして、ピーク検出部20dにより例えば受信信号の3番目の波形のピーク値をピーク検知信号として選択する。このため、受信手段21bが記録材Pを介した超音波を受信する場合、超音波の受信信号の増幅率が大きくなることを抑制でき、超音波を受信する回路に存在するノイズが坪量の検知結果に及ぼす影響を低減することができる。 As described above, in this embodiment, the magnitude of the amplitude of the output signal is switched according to the presence / absence of the recording material P, and the peak detection unit 20d determines the peak value of the received signal according to the presence / absence of the recording material. Switch the waveform to be detected. That is, when the receiving means 21b receives the ultrasonic wave that does not pass through the recording material P, the peak detection unit 20d selects, for example, the peak value of the first waveform of the received signal as the peak detection signal. Further, when the receiving means 21b receives the ultrasonic waves via the recording material P, the amplitude of the output signal is increased as compared with the case where the receiving means 21b receives the ultrasonic waves not passing through the recording material P. Then, the peak detection unit 20d selects, for example, the peak value of the third waveform of the received signal as the peak detection signal. Therefore, when the receiving means 21b receives the ultrasonic wave via the recording material P, it is possible to suppress an increase in the amplification factor of the ultrasonic wave reception signal, and the noise existing in the circuit for receiving the ultrasonic wave has a basis weight. The effect on the detection result can be reduced.

なお、本実施例において、ピーク検出部20dが記録材の有無に応じて、受信信号のうちピーク値を検知する波形を切り替える方法として、駆動信号と同期した所定時間の間の検知信号を検知する方法について記載した。しかし、ピーク値を検知する波形を切り替える方法としてはこれに限らない。例えば、ピーク値を検知する波形を切り替える方法として、受信レベル検知部20cにより、受信検知部23で生成された検知信号から変換されたデジタル信号を用いて、検知信号の波形を検知し、波形をカウントする方法であっても良い。このとき、検知信号のデジタル信号が最大となり波形がピーク値となるポイントをカウントしても良いし、検知信号のデジタル信号が0の値となり波形が横軸と交わるポイントをカウントしても良い。 In this embodiment, the peak detection unit 20d detects the detection signal for a predetermined time synchronized with the drive signal as a method of switching the waveform for detecting the peak value among the received signals according to the presence or absence of the recording material. The method was described. However, the method of switching the waveform for detecting the peak value is not limited to this. For example, as a method of switching the waveform for detecting the peak value, the reception level detection unit 20c detects the waveform of the detection signal using the digital signal converted from the detection signal generated by the reception detection unit 23, and obtains the waveform. It may be a counting method. At this time, the point where the digital signal of the detection signal becomes the maximum and the waveform becomes the peak value may be counted, or the point where the digital signal of the detection signal becomes a value of 0 and the waveform intersects the horizontal axis may be counted.

また本実施例においては、ピーク値を検知する波形を切り替える方法として、以下のような方法であっても良い。例えば、製造工程において予め超音波センサにより検知信号を検知し、検知信号の受信レベルが飽和しない値に閾値を設け、発信手段に駆動入力が入力されてから検知信号が閾値Vthを超えるまでの時間を検知する方法であっても良い。この場合、例えば、検知信号の受信レベルが飽和しない値、すなわち、受信信号が受信検知部23によって検知可能な信号の上限値よりも小さい値に、閾値としてVthを設ける。受信手段が記録材を介していない超音波を受信する場合、発信手段に駆動入力が入力されてから検知信号が閾値Vthの値以上となるまでの時間をTaとする。また、受信手段が記録材を介した超音波を受信する場合、発信手段に駆動入力が入力されてから検知信号が閾値Vthの値以上となるまでの時間をTpとする。このようにして得られたTaとTpに応じて、記録材Pの坪量を検知する方法であっても良い。なお、Taを第1の期間とも称し、Tpを第2の期間とも称する。 Further, in this embodiment, the following method may be used as a method for switching the waveform for detecting the peak value. For example, in the manufacturing process, a detection signal is detected in advance by an ultrasonic sensor, a threshold value is set for a value at which the reception level of the detection signal is not saturated, and the time from when the drive input is input to the transmitting means until the detection signal exceeds the threshold value Vth. It may be a method of detecting. In this case, for example, Vth is set as a threshold value at a value at which the reception level of the detection signal is not saturated, that is, a value at which the received signal is smaller than the upper limit value of the signal that can be detected by the reception detection unit 23. When the receiving means receives ultrasonic waves that do not pass through the recording material, the time from when the drive input is input to the transmitting means until the detection signal becomes equal to or higher than the threshold value Vth is defined as Ta. Further, when the receiving means receives the ultrasonic wave via the recording material, the time from the input of the drive input to the transmitting means until the detection signal becomes equal to or higher than the threshold value Vth is defined as Tp. A method of detecting the basis weight of the recording material P may be used according to the Ta and Tp thus obtained. In addition, Ta is also referred to as a first period, and Tp is also referred to as a second period.

この方法を用いる場合、記録材Pの有無に応じて出力信号の振幅の大きさを切り替える際に、駆動電圧は記録材Pの有無によらず一定で、記録材Pの有無に応じて発信指示部20aにより出力される駆動信号の周波数を切り替えても良い。例えば、超音波の振幅が最大となるときの駆動信号の周波数を第1の周波数とし、駆動信号が第1の周波数である時の超音波よりも振幅が小さい超音波となる駆動信号の周波数を第2の周波数とする。この場合、受信手段が記録材を介した超音波を受信する場合において、発信指示部20aは第1の周波数であるパルス波を駆動信号として出力する。また、受信手段が記録材を介していない超音波を受信する場合において、発信指示部20bは第2の周波数であるパルス波を駆動信号として出力する。これにより、受信手段が記録材を介した超音波を受信する場合において、受信手段が記録材を介していない超音波を受信する場合よりも大きな振幅の超音波を、発信手段21aによって出力することが出来る。このため、受信手段が記録材を介した超音波を受信する場合に受信信号を増幅することにより生じる信号雑音比が大きくなることを抑制することができる。よって、記録材Pの坪量の検知を従来よりも高精度で行うことが可能となる。 When this method is used, when the magnitude of the amplitude of the output signal is switched according to the presence / absence of the recording material P, the drive voltage is constant regardless of the presence / absence of the recording material P, and the transmission instruction is given according to the presence / absence of the recording material P. The frequency of the drive signal output by the unit 20a may be switched. For example, the frequency of the drive signal when the amplitude of the ultrasonic wave is maximum is set as the first frequency, and the frequency of the drive signal which is an ultrasonic wave having a smaller amplitude than the ultrasonic wave when the drive signal is the first frequency is set. Let it be the second frequency. In this case, when the receiving means receives the ultrasonic wave via the recording material, the transmission instruction unit 20a outputs a pulse wave having a first frequency as a drive signal. Further, when the receiving means receives ultrasonic waves that do not pass through the recording material, the transmission instruction unit 20b outputs a pulse wave having a second frequency as a drive signal. As a result, when the receiving means receives the ultrasonic wave through the recording material, the transmitting means 21a outputs an ultrasonic wave having a larger amplitude than when the receiving means receives the ultrasonic wave not passing through the recording material. Can be done. Therefore, it is possible to suppress an increase in the signal-to-noise ratio generated by amplifying the received signal when the receiving means receives the ultrasonic wave through the recording material. Therefore, it is possible to detect the basis weight of the recording material P with higher accuracy than before.

また、駆動電圧と発信指示部20aにより出力される駆動信号の周波数は記録材Pの有無によらず一定とし、記録材Pの有無に応じて駆動信号のHigh信号とLow信号のDuty比を切り替えても良い。これにより、受信手段が記録材を介した超音波を受信する場合において、受信手段が記録材を介していない超音波を受信する場合よりも大きな振幅の超音波を、発信手段21aによって出力することが出来る。このため、受信手段が記録材を介した超音波を受信する場合に受信信号を増幅することにより生じる信号雑音比が大きくなることを抑制することができる。 Further, the drive voltage and the frequency of the drive signal output by the transmission instruction unit 20a are constant regardless of the presence or absence of the recording material P, and the duty ratio of the high signal and the low signal of the drive signal is switched according to the presence or absence of the recording material P. May be. As a result, when the receiving means receives the ultrasonic wave through the recording material, the transmitting means 21a outputs an ultrasonic wave having a larger amplitude than when the receiving means receives the ultrasonic wave not passing through the recording material. Can be done. Therefore, it is possible to suppress an increase in the signal-to-noise ratio generated by amplifying the received signal when the receiving means receives the ultrasonic wave through the recording material.

1 画像形成装置
19 記録材判別装置
20 制御部
20a 切替指示部
20b 増幅率切替指示部
20d ピーク検出部
21 超音波センサ
21a 発信手段
21b 受信手段
22 発信回路部
1 Image forming device 19 Recording material discrimination device 20 Control unit 20a Switching instruction unit 20b Amplification rate switching instruction unit 20d Peak detection unit 21 Ultrasonic sensor 21a Transmission means 21b Reception means 22 Transmission circuit unit

Claims (6)

超音波を発信する発信手段と、前記超音波を受信する受信手段と、を有し、前記発信手段と前記受信手段が、記録材が搬送される搬送路を挟むように設けられた超音波センサと、
前記発信手段に駆動入力を入力する指示手段と、
前記超音波センサにより受信した受信信号が入力され第1値以下の振幅の波を出力する受信検知手段と、
記録材を介していない超音波を前記受信手段により受信する場合、前記受信検知手段により前記第1値未満の振幅の波が出力される期間であって、前記発信手段に駆動入力が入力されてから第1の時間が経過した後且つ第2の時間が経過するまでの期間に前記受信検知手段により出力された第1の波の振幅情報と、記録材を介した超音波を前記受信手段により受信する場合、前記受信検知手段により前記第1値未満の振幅の波が出力される期間であって、前記発信手段に駆動入力が入力されてから第3の時間が経過した後且つ第4の時間が経過するまでの期間に前記受信検知手段により出力された第2の波の振幅情報と、に応じて記録材の坪量に関する情報を検知する坪量検知手段と、を備え、
前記第1の時間は前記第3の時間よりも短いことを特徴とする記録材検知装置。
An ultrasonic sensor having a transmitting means for transmitting ultrasonic waves and a receiving means for receiving the ultrasonic waves, and the transmitting means and the receiving means are provided so as to sandwich a transport path through which a recording material is conveyed. When,
An instruction means for inputting a drive input to the transmission means and
A reception detection means for inputting a reception signal received by the ultrasonic sensor and outputting a wave having an amplitude equal to or lower than the first value.
When the ultrasonic wave that does not pass through the recording material is received by the receiving means, the drive input is input to the transmitting means during the period during which the receiving detecting means outputs a wave having an amplitude less than the first value. The amplitude information of the first wave output by the reception detection means and the ultrasonic wave via the recording material are transmitted by the reception means during the period from the first time to the second time. In the case of reception, it is a period during which a wave having an amplitude less than the first value is output by the reception detecting means, and after a third time has elapsed from the input of the drive input to the transmitting means and the fourth. It is provided with the amplitude information of the second wave output by the reception detecting means in the period until the time elapses, and the basis weight detecting means for detecting the information about the basis weight of the recording material according to the amplitude information.
The recording material detection device, characterized in that the first time is shorter than the third time.
前記受信信号を増幅する増幅率切替手段と、
前記受信信号の増幅率を切り替える増幅率切替信号を前記増幅率切替手段に出力する増幅率切替指示手段とを備え、
前記増幅率切替手段は、記録材を介した超音波を前記受信手段により受信する場合、第1の増幅率で前記受信信号を増幅し、記録材を介していない超音波を前記受信手段により受信する場合、前記第1の増幅率よりも大きい第2の増幅率で前記受信信号を増幅することを特徴とする請求項1に記載の記録材検知装置。
Amplification rate switching means for amplifying the received signal and
It is provided with an amplification factor switching instruction means for outputting an amplification factor switching signal for switching the amplification factor of the received signal to the amplification factor switching means.
When the receiving means receives the ultrasonic waves via the recording material, the amplification factor switching means amplifies the received signal at the first amplification factor and receives the ultrasonic waves not passing through the recording material by the receiving means. The recording material detection device according to claim 1, wherein the received signal is amplified with a second amplification factor larger than that of the first amplification factor.
前記指示手段は、記録材の有無に応じて前記指示手段が前記発信手段に入力する駆動入力を切り替える駆動入力切替手段を有し、
前記駆動入力切替手段は、記録材を介していない超音波を前記受信手段により受信する場合、前記発信手段に第1の駆動入力を入力し、記録材を介した超音波を前記受信手段により受信する場合、前記発信手段に前記第1の駆動入力よりも大きい第2の駆動入力を入力し、
前記第1の駆動入力を入力された場合に前記発信手段が発信する超音波の振幅は、前記第2の駆動入力を入力された場合に前記発信手段が発信する超音波の振幅よりも小さいことを特徴とする請求項1または2に記載の記録材検知装置。
The instruction means has a drive input switching means for switching a drive input to be input to the transmission means by the instruction means depending on the presence or absence of a recording material.
When the drive input switching means receives ultrasonic waves that do not pass through the recording material by the receiving means, the drive input switching means inputs the first drive input to the transmitting means and receives the ultrasonic waves that pass through the recording material by the receiving means. In this case, a second drive input larger than the first drive input is input to the transmission means.
The amplitude of the ultrasonic wave transmitted by the transmitting means when the first drive input is input is smaller than the amplitude of the ultrasonic wave transmitted by the transmitting means when the second drive input is input. The recording material detection device according to claim 1 or 2.
前記第1値は、前記受信検知手段により出力される波の振幅の最大値であることを特徴とする請求項1乃至3のいずれか一項に記載の記録材検知装置。 The recording material detection device according to any one of claims 1 to 3, wherein the first value is the maximum value of the amplitude of the wave output by the reception detection means. 超音波を発信する発信手段と、前記超音波を受信する受信手段と、を有し、前記発信手段と前記受信手段が、記録材が搬送される搬送路を挟むように設けられた超音波センサと、
前記発信手段に駆動入力を入力する指示手段と、
前記超音波センサにより受信した受信信号が入力され第1値以下の振幅の波を出力する受信検知手段と、
記録材を介していない超音波を前記受信手段により受信する場合、前記受信検知手段により前記第1値未満の振幅の波が出力される期間であって、振幅が前記第1値よりも小さい第2値以上となるまでの第1の期間と、記録材を介した超音波を前記受信手段により受信する場合、前記受信検知手段により前記第1値未満の振幅の波が出力される期間であって、振幅が前記第2値以上となるまでの第2の期間と、に応じて記録材の坪量に関する情報を検知する坪量検知手段と、を備えることを特徴とする記録材検知装置。
An ultrasonic sensor having a transmitting means for transmitting ultrasonic waves and a receiving means for receiving the ultrasonic waves, and the transmitting means and the receiving means are provided so as to sandwich a transport path through which a recording material is conveyed. When,
An instruction means for inputting a drive input to the transmission means and
A reception detection means for inputting a reception signal received by the ultrasonic sensor and outputting a wave having an amplitude equal to or lower than the first value.
When the ultrasonic wave that does not pass through the recording material is received by the receiving means, the reception detecting means outputs a wave having an amplitude less than the first value, and the amplitude is smaller than the first value. The first period until the value becomes 2 or more, and the period when the reception detecting means outputs a wave having an amplitude less than the first value when the ultrasonic wave through the recording material is received by the receiving means. The recording material detecting device is provided with a second period until the amplitude becomes equal to or higher than the second value, and a basis weight detecting means for detecting information on the basis weight of the recording material according to the second period.
記録材に画像を形成する画像形成手段を有し、
請求項1乃至5のいずれか一項に記載の記録材判別装置によって検知した検知結果に基づいて前記画像形成手段により画像を形成する条件を変更することを特徴とする画像形成装置。
It has an image forming means for forming an image on a recording material, and has an image forming means.
An image forming apparatus, characterized in that the conditions for forming an image are changed by the image forming means based on the detection result detected by the recording material discriminating apparatus according to any one of claims 1 to 5.
JP2020210445A 2020-12-18 2020-12-18 Recording material detector and image forming apparatus Pending JP2022097072A (en)

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