JPH02231344A - Paper form detecting device - Google Patents
Paper form detecting deviceInfo
- Publication number
- JPH02231344A JPH02231344A JP1050129A JP5012989A JPH02231344A JP H02231344 A JPH02231344 A JP H02231344A JP 1050129 A JP1050129 A JP 1050129A JP 5012989 A JP5012989 A JP 5012989A JP H02231344 A JPH02231344 A JP H02231344A
- Authority
- JP
- Japan
- Prior art keywords
- paper
- output
- distance
- light
- delay
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000001514 detection method Methods 0.000 claims abstract description 43
- 238000003708 edge detection Methods 0.000 claims description 3
- 230000007423 decrease Effects 0.000 description 6
- 238000010586 diagram Methods 0.000 description 5
- 230000035945 sensitivity Effects 0.000 description 4
- 230000007257 malfunction Effects 0.000 description 3
- 230000003111 delayed effect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000002441 reversible effect Effects 0.000 description 2
- 238000000034 method Methods 0.000 description 1
- 238000002834 transmittance Methods 0.000 description 1
Landscapes
- Controlling Sheets Or Webs (AREA)
- Registering Or Overturning Sheets (AREA)
- Geophysics And Detection Of Objects (AREA)
- Paper Feeding For Electrophotography (AREA)
- Control Or Security For Electrophotography (AREA)
Abstract
Description
【発明の詳細な説明】
(産業上の技術分野)
本発明は,プリンタ,複写機等の給紙装置において、用
紙の有無おなび予備給紙した用紙の給紙タイミングを制
御する用紙検知装置に関する。Detailed Description of the Invention (Industrial Technical Field) The present invention relates to a paper detection device for controlling the presence or absence of paper and the feeding timing of pre-fed paper in paper feeding devices such as printers and copying machines. .
(従来の技術)
給紙検知装置の構成例を第5図,第6図に示し、第5図
の場合は一対の搬送ローラ1,2により平行配置された
ガイド板3,4に沿って矢印方向へ用紙6が実線(a)
または点線(b)の経路で搬送され,反射型ホトセンサ
5で用紙の有,無を検知する。(Prior Art) Examples of the configuration of a paper feed detection device are shown in FIGS. 5 and 6. In the case of FIG. Direction of paper 6 is solid line (a)
Alternatively, the sheet is conveyed along the path indicated by the dotted line (b), and the reflective photosensor 5 detects the presence or absence of the sheet.
また,第6図の場合はガイド板3,4が折曲していて、
用紙を搬送経路a,bで搬送する例である,
ところで、この反射型ホトセンサ5で用紙6の有無を検
知するわけであるが,用紙の種類、ガイド板内の用紙と
反射型ホトセンサとの距離d、あるいは反射型ホトセン
サの焦点距離とにより、その出力が変化する.
用紙の種類において,例えばOHP用紙や第2原図用紙
と普通紙とでは、その反射率,透過率が異なる.OHP
用紙や第2M図用紙の方が普通紙より反射率が小さいた
めに反射型ホトセンサのLED照射光量が同じであるな
らばOHP用紙や第2原図用紙の方が普通紙に比べ反射
光量が小さい.このため、反射型ホトセンサのコレクタ
出力電流が小さくなり、従ってその出力電圧も小さくな
る.第7図,第8図に示す反射形ホトセンサの出力波形
は、夫々第5図,第6図の給紙検知装置における普通紙
(1点鎖線)とOHP用紙や第2M図用紙(実1lA)
の場合を夫々示す.
ここで,光の光度は周知のように距離の自乗に反比例す
るので、コレクタ出力電流ICは、第9図に示すように
用紙と反射型ホトセンサとの距離dmによって変化する
.また、反射型ホトセンサは、焦点距離(第9図ではd
=2m+)があり、この焦点距離より遠いところでは、
距離dが小さい程、コレクタ出力電流■。は大きくなり
、距離dが大きい程、コレクタ出力電流ICは小さくな
る.また焦点距離より近い所では、その逆である。In addition, in the case of Fig. 6, the guide plates 3 and 4 are bent,
This is an example in which paper is transported along transport paths a and b. By the way, the presence or absence of paper 6 is detected by this reflective photosensor 5, but depending on the type of paper and the distance between the paper in the guide plate and the reflective photosensor, The output changes depending on d or the focal length of the reflective photosensor. Regarding paper types, for example, OHP paper, second original paper, and plain paper have different reflectance and transmittance. OHP
Since the reflectance of paper and 2M drawing paper is lower than that of plain paper, if the amount of light irradiated by the LED of the reflective photo sensor is the same, the amount of reflected light will be smaller for OHP paper and 2nd original drawing paper than for plain paper. Therefore, the collector output current of the reflective photosensor becomes smaller, and therefore its output voltage also becomes smaller. The output waveforms of the reflective photosensor shown in Figs. 7 and 8 are for plain paper (dotted chain line), OHP paper, and paper (actual 1lA) in Fig. 2M paper in the paper feed detection device of Figs. 5 and 6, respectively.
The following cases are shown below. Here, since the luminous intensity of light is inversely proportional to the square of the distance, as is well known, the collector output current IC changes depending on the distance dm between the paper and the reflective photosensor, as shown in FIG. In addition, the reflective photosensor has a focal length (d in Fig. 9).
=2m+), and at locations farther than this focal length,
The smaller the distance d, the collector output current ■. The larger the distance d, the smaller the collector output current IC. The opposite is true at locations closer than the focal length.
(発明が解決しようとする課題)
第5図や第6図に示す給紙検知装置で用紙を搬送する場
合、用紙6と反射型ホトセンサ5との距離dは一定でな
く用紙の状態により常に変化する.例えば,薄い用紙や
バックカールのある用紙の先端は第5図aの搬送経路の
ようにガイド板4に沿って移動し、また通常の厚さで、
バックカールのない用紙(腰のある用紙)は第5図bの
搬送経路ように2つの搬送ローラ1,2によって搬送さ
れる.この結果、搬送経路aを通る用紙6は、搬送経路
bを通る用紙6に比べ,距離(Δd)だけ距離が長<(
d+Δd)なる。これを、第9図の距離dとコレクタ出
力電流ICの特性からみると、距離dが1mm遠くなる
とコレクタ出力電流工。が約18%減少する.
また、第6図に示す給紙検知装置のように搬送経路が折
曲っている場合には、腰のある厚い用紙でも搬送経路が
a,bに示すように反射型ホトセンサ5と用紙6の距離
が変化する。(Problem to be Solved by the Invention) When paper is conveyed using the paper feed detection device shown in FIGS. 5 and 6, the distance d between the paper 6 and the reflective photosensor 5 is not constant and always changes depending on the state of the paper. do. For example, the leading edge of thin paper or paper with back curls moves along the guide plate 4 as shown in the conveyance path in FIG.
Paper without back curl (paper with stiffness) is conveyed by two conveyance rollers 1 and 2 as shown in the conveyance path shown in FIG. 5b. As a result, the paper 6 passing through the transport path a is longer by the distance (Δd) than the paper 6 passing through the transport route b.
d+Δd). Looking at this from the distance d and the characteristics of the collector output current IC in Fig. 9, if the distance d increases by 1 mm, the collector output current will change. decreases by approximately 18%. In addition, when the conveyance path is bent as in the paper feed detection device shown in FIG. changes.
上記において、反射率が大きく、その反射光量が大きな
用紙であれば、距離の変化は差程、問題にならないが、
反射率の小さい用紙であれば、第8図(第6図に示す給
紙検知装置)のOHP用紙や第2原図用紙の場合(実線
)のように、反射型ホトセンサ5のコレクタ出力電流I
Cが距離dによって大きく変化する。In the above, if the paper has a high reflectance and a large amount of reflected light, the change in distance will not be much of a problem.
If the paper has a low reflectance, the collector output current I of the reflective photosensor 5 is
C changes greatly depending on the distance d.
もし、用紙検知の基準電圧が第8図に示すVlであれば
、上記コクレタ出力電流Ic(その出力電圧)と比較す
る比較器出力が紙有り(Lowレベル)になるのに検知
の遅れ(Δt)が生じる.従来の用紙検知装置のように
比較器の基準値が1つの場合には,上述した用紙と反射
型ホトセンサとの距離の変化があって、用紙先端の検知
遅れ(Δt)を防ぐには,第8図において、基準電圧v
3をvcのように距11tclが最も大きいときに合せ
て設定するか,センサの感度を上げる方法をとっていた
.しかし、距離dの変化量が非常に大きい場合には,基
準電圧値を下げ過ぎたり、センサ感度を上げ過ぎること
になり、反面,外乱光等の影響による誤動作に対するマ
ージン(M)が少なくなるという不具合が生じる。If the reference voltage for paper detection is Vl shown in FIG. ) occurs. When the comparator has one reference value as in the conventional paper detection device, there is a change in the distance between the paper and the reflective photosensor as described above, and in order to prevent the detection delay (Δt) of the leading edge of the paper, it is necessary to In Figure 8, the reference voltage v
3 to match the distance 11tcl is the largest, such as VC, or increase the sensitivity of the sensor. However, if the amount of change in the distance d is extremely large, the reference voltage value will be lowered too much or the sensor sensitivity will be increased too much, and on the other hand, the margin (M) against malfunction due to the influence of ambient light etc. will decrease. A problem occurs.
また、別の従来例として1つの発光部に対して複数の受
光部を設けた物体の位置検出装置(特開昭60−101
01号)が提案されている.これは、位置検出精度は向
上するが,2つの受光部の基準電圧値は同一であり、反
射率の小さい用紙を使用し,センサとの距離dの変化量
が大きい場合には,基準電圧値を低くするか,センサ感
度を上げる等の方法も考えられるが、外乱光等の影響に
よる誤動作が生じる恐れがある.
また,複数のホトセンサを用いて、そのうちの1つを基
準電圧とするシート有無検知装置(特開昭62−111
5656号)においては、ホトセンサ及びそのレベル調
整アンプのバラツキの問題があり、外乱光等の影響で,
一方のセンサのみが光が当る場合には誤動作となる恐れ
がある。In addition, as another conventional example, an object position detection device (Japanese Patent Laid-Open No. 60-101
No. 01) has been proposed. This improves position detection accuracy, but the reference voltage values of the two light receiving sections are the same, and if paper with low reflectance is used and the amount of change in distance d from the sensor is large, the reference voltage value Methods such as lowering the sensor sensitivity or increasing the sensor sensitivity may be considered, but there is a risk that malfunctions may occur due to the effects of ambient light. In addition, a sheet presence/absence detection device using multiple photosensors and using one of them as a reference voltage (Japanese Patent Laid-Open No. 62-111
No. 5656), there is a problem with variations in the photo sensor and its level adjustment amplifier, and due to the influence of external light, etc.
If only one sensor is exposed to light, there is a risk of malfunction.
次に用紙のフィード量について考察すると、第6図の給
紙検知装置では、反射型ホトセンサ5の位置iこ用紙6
の先端が達した時間を基準として給紙タイミングを制御
している.しかし,上述したように用紙先端の検知遅れ
(Δ1)(第8図)があると、その時間差分.用紙停止
位置がのびる.つまりその分時間が小さくなる.即ち,
第8図において、検知遅れ(Δt)より級間の減少分は
、線速×Δtとなる.そして、この減少分が大きくなり
、紙間がゼロとなるとジャムとなる。Next, considering the amount of paper feed, in the paper feed detection device shown in FIG.
The paper feeding timing is controlled based on the time when the leading edge of the paper reaches the paper. However, as mentioned above, if there is a delay in detecting the leading edge of the paper (Δ1) (Fig. 8), the time difference. The paper stop position is extended. In other words, the time becomes shorter. That is,
In Fig. 8, the decrease between classes due to the detection delay (Δt) is linear velocity x Δt. Then, if this decrease becomes large and the paper gap becomes zero, a jam occurs.
また、用紙が予備給紙(詳細は後述する)した位置で紙
間がゼロでなくても、プリントエンジン自体の線速が給
紙装置の線速より遅い場合は、レジストローラ部で追い
つかないような最小紙間が必要である.
なお、前記予備給紙(プレフイード)は、用紙先端をレ
ジストローラ(図略)のニップと搬送ローラ2のニップ
に停止させてか返,搬送する場合の級間は,このニップ
間の距離からレジストローラ部にある用紙の長さを引い
たものであるので、長さが短い用紙ほど紙間は大きくな
る.したがって、線速が一定の場合、紙間が大きいほど
,単位時間当りの搬送距離中の枚数が少いので、プリン
トスピードは遅くなる.そこで、予め用紙を少し搬送し
紙間を小さくする.この動作をプレフイードと?い、プ
リントスピードを上げることができる.本発明は上述し
た従来装置において,1個の基準電圧VBによる用紙先
端の検知遅れ(Δt)に起因して級間の減少によるジャ
ム発生を防止し,異なる2つ以上の基準電圧V■VCを
設け、反射型ホトセンサと用紙との距離dの変化が生じ
ても検知遅れ時間に対応して予備給紙した用紙の給紙タ
イミングを変化させることにより、常に紙間を一定に保
ちプリントスピードを一定に保つことを目的とする.
(構成および作用)
本発明は上記目的を達成するため、通紙中の用紙からの
反射光量を受光する受光素子と、該受光素子出力を夫々
一方の入力とする,予め通紙する用紙中,最も反射率の
小さい用紙で、かつ該用紙が前記受光素子との距離にお
いて.最も安定搬送されたときの該受光素子出力にマー
ジンを含めた基準電圧VBを他方の入力とした第1の比
較器と,前記最も反射率の小さい用紙がガイド板に沿っ
て前記受光素子から,最も離れた距離のときの該受光出
力を有する基準電圧Vcを他方の入力とした第2め比較
器と,前記第1,第2の比較器出力を入力として用紙先
端検知の遅れを検出する排他的論理和回路とで構成され
たことを特徴とする.本発明は用紙がレイアウト上の最
大位11dmaxと基準位置d aveの間にあり,第
1の比較器出力が紙有り(Lowレベル)になっている
場合には、排他的論理和回路がH ighレベルになっ
て検知遅れを示す.一方、用紙がなく第1,第2の比較
器が共にHighレベルの場合や,用紙が標準位11d
aveより反射型ホトセンサに近く搬送され,第1の比
較器で検知され,第1,第2の比較器が共にLovレベ
ルの場合は検知遅れがないことを示す.そして、用紙先
端検知の遅れ時間に応じて給紙タイミングを可変するこ
とにより紙間を一定に保ち、プリントスピードを一定に
保つものである.(実施例)
第1図は本発明の一実施例の回路構成図を示し、5は反
射型ホトセンサで,発光ダイオード(LED)51とホ
トトランジスタ52でなる.7は第1の比較器で,その
一方の入力端子(−)には、前記ホトトランジスタから
用紙の反射光量に見合った受光出力が入力される.また
他方の入力端子(+)には,基準電圧源IOから基準電
圧V,が加えられる.これは前記第8図で説明したよう
に,通紙する用紙6のうちで,最ル反射率の小さい用紙
が,第6図(あるいは第5図)に示す搬送ローラ1,2
の両方で搬送されているときの距離d(搬送経路bの用
紙位5!),つまり、距離のバラツキが小さく最も安定
して搬送されているときの用紙と反転型ホトセンサ5と
の距離dにおけるホトトランジスタ52の出力を基準と
し,それにマージンMを考慮して設定される.
8は第2の比較器で,その一方の入力端子(−)には前
記第1の比較器7の入力端子(一)に入力された反射型
ホトセンサ5のホトトランジスタ52の出力が入力され
る.また他方の入力端子(+)には基準電圧源11から
基準電圧vcが加えられる.これは、前記第8図で説明
したように通紙する用紙6のうちで最も反射率の小さい
用紙が、第6図(あるいは第5図)に示すガイド板3,
4に沿って搬送されているときの距離d(搬送経路aの
用紙位置),つまり、距離が最も反射型ホトセンサ5か
ら離れて搬送されているときの用紙と該反射型ホトセン
サ5の距離d′におけるホトトランジスタ52の出力を
基準として設定される.9は前記第1の比較器7の出力
E1および第2の比較器8の出力E2′を入力とし、出
力E,(表)をうる徘他的論理和(EX−OR)回路で
ある.次に動作を第3図の給紙のタイミングを変える場
合のフローチャートおよび第4図のプレフィード解除の
場合のフローチャートにより説明する.反射型ホトセン
サ5は電源電圧vceが一定の場合には、発光ダイオー
ド(LED)51の照射光量は一定であり、ホトトラン
ジスタ52の入射光量は,用紙6の反射率と、用紙6と
ホトトランジスタ52の距離d(またはd’)に応じて
変化する.第1の比較器7は用紙6の有,無を検知する
ものとし,一方の入力端子(一)にホトトランジスタ5
2からの出力があった時、他方の入力端子(+)へ?基
準電圧値v1と比較され、用紙6が搬送経路aまたはb
にあると入力電圧が基準電圧v1を越え、出力E1(L
owレベル)をうる.この出力E■を基準として用紙の
有無が判断され,その出力E1は排他的論理和回路9の
一方の入力となる.また、第2の比較器8においては、
用紙6の先端を検知するものとし、一方の入力端子(−
)にホトトランジスタ52からの出力があった時、他方
の入力端子(+)への基準電圧Vcと比較され、用紙6
が搬送経路aまたはbにあると、入力電圧が基準電圧V
Cを越え、出力E.’(Lowレベル)を得て排他的論
理和回路9の他方の入力となる.該排他的論理和回路9
は前記第1,第2の比較器7,8の出力Eエ,E2′か
ら第1図の表に示す出力E,(“0”はLow,“1”
はHigh)を得る.つまり、出力E,に出力E1の検
知遅れ信号を出力する。Also, even if the paper gap is not zero at the position where the paper is pre-fed (details will be explained later), if the linear speed of the print engine itself is slower than the linear speed of the paper feeder, the registration rollers may not be able to catch up. A minimum paper spacing is required. Note that the pre-feeding is performed by stopping the leading edge of the paper at the nip of the registration roller (not shown) and the nip of the transport roller 2, and then returning the paper to the nip of the registration roller (not shown). It is calculated by subtracting the length of the paper in the roller section, so the shorter the paper, the larger the paper gap. Therefore, when the linear speed is constant, the larger the paper distance, the fewer sheets are transported per unit time, and the printing speed becomes slower. Therefore, the paper is conveyed a little in advance to reduce the paper gap. Is this behavior called prefeed? You can increase printing speed. The present invention prevents jam occurrence in the above-mentioned conventional apparatus due to a decrease in the grade due to a detection delay (Δt) of the leading edge of the paper due to one reference voltage VB, and prevents jams caused by a decrease in the number of grades by using two or more different reference voltages V Even if the distance d between the reflective photosensor and the paper changes, the paper feeding timing of the pre-fed paper is changed in response to the detection delay time to keep the paper distance constant and the printing speed constant. The purpose is to maintain (Structure and operation) In order to achieve the above object, the present invention includes a light receiving element that receives the amount of reflected light from the paper being passed through, and a light receiving element that receives the output of the light receiving element as one input. A sheet of paper with the lowest reflectance, and at a distance between the sheet and the light-receiving element. a first comparator whose other input is a reference voltage VB, which is the output of the light receiving element including a margin when the paper is transported most stably; a second comparator whose other input is the reference voltage Vc having the received light output at the farthest distance; and an exclusive device which uses the outputs of the first and second comparators as inputs to detect a delay in paper leading edge detection. It is characterized by being composed of a logical OR circuit. In the present invention, when the paper is between the maximum position 11dmax on the layout and the reference position dave, and the first comparator output is paper present (Low level), the exclusive OR circuit is set to High. level, indicating a detection delay. On the other hand, if there is no paper and both the first and second comparators are at High level, or the paper is at the standard level 11d.
ave is transported closer to the reflective photo sensor and detected by the first comparator, and if both the first and second comparators are at Lov level, it indicates that there is no detection delay. Then, by varying the paper feeding timing according to the delay time of paper leading edge detection, the paper spacing is kept constant and the printing speed is kept constant. (Embodiment) FIG. 1 shows a circuit configuration diagram of an embodiment of the present invention. Reference numeral 5 denotes a reflective photosensor, which is composed of a light emitting diode (LED) 51 and a phototransistor 52. Reference numeral 7 designates a first comparator, and one input terminal (-) of the comparator receives the received light output from the phototransistor corresponding to the amount of reflected light from the paper. In addition, a reference voltage V is applied to the other input terminal (+) from a reference voltage source IO. This is because, as explained in FIG. 8 above, among the sheets of paper 6 passing through, the sheet with the lowest reflectance is the one that is attached to the conveyor rollers 1 and 2 shown in FIG. 6 (or FIG. 5).
The distance d between the paper and the reversible photosensor 5 when the paper is being transported in both directions (paper position 5 on transport path b!), that is, the distance d between the paper and the reversible photosensor 5 when the paper is being transported most stably with little variation in distance. It is set using the output of the phototransistor 52 as a reference and taking into account the margin M. 8 is a second comparator, one input terminal (-) of which receives the output of the phototransistor 52 of the reflective photosensor 5, which is input to the input terminal (1) of the first comparator 7. .. Further, a reference voltage vc is applied from a reference voltage source 11 to the other input terminal (+). This is because, as explained in FIG. 8, the paper with the lowest reflectance among the paper sheets 6 passing through is the guide plate 3 shown in FIG. 6 (or FIG. 5).
4 (sheet position on transport path a), that is, the distance d' between the paper and the reflective photosensor 5 when the paper is transported farthest from the reflective photosensor 5. is set based on the output of the phototransistor 52 at . 9 is an EX-OR circuit which receives the output E1 of the first comparator 7 and the output E2' of the second comparator 8 and outputs the output E, (table). Next, the operation will be explained with reference to the flowchart in FIG. 3 for changing the paper feeding timing and the flowchart for canceling prefeed in FIG. In the reflective photosensor 5, when the power supply voltage vce is constant, the amount of light irradiated by the light emitting diode (LED) 51 is constant, and the amount of light incident on the phototransistor 52 is determined by the reflectance of the paper 6 and the amount of light between the paper 6 and the phototransistor 52. It changes depending on the distance d (or d'). The first comparator 7 detects the presence or absence of paper 6, and has one input terminal (1) connected to a phototransistor 5.
When there is an output from 2, to the other input terminal (+)? It is compared with the reference voltage value v1, and the paper 6 is transferred to the transport path a or b.
, the input voltage exceeds the reference voltage v1 and the output E1 (L
ow level). The presence or absence of paper is determined based on this output E■, and the output E1 becomes one input of the exclusive OR circuit 9. Moreover, in the second comparator 8,
It is assumed that the leading edge of the paper 6 is detected, and one input terminal (-
), when there is an output from the phototransistor 52, it is compared with the reference voltage Vc to the other input terminal (+), and the paper 6
is on the transport path a or b, the input voltage is equal to the reference voltage V
C and the output E. ' (Low level) and becomes the other input of the exclusive OR circuit 9. The exclusive OR circuit 9
are the outputs E, E2' of the first and second comparators 7 and 8, and the output E shown in the table of FIG. 1 ("0" is Low, "1"
is High). That is, the detection delay signal of the output E1 is output to the output E.
例えば,用紙が第6図搬送経路上、最大位置dmax(
距離d’)と標準位[dave(距離d)の間にあり、
第1の比較器7の出力E■がLowレベル(11 0
′F用紙有り),第2の比較器8の出力E2′がHig
hレベル(” 1 ’″用紙先端無し)の場合には、出
力E2がHighレベル(“1”)になり,検知遅れが
あることを示す.
一方,用紙がなく両方の比較器7,8がHighレベル
(“1”用紙無し)の場合や,用紙6が標準位置d a
veより近くを搬送され、第1の比較器7で検知され,
両方の比較器7,8がLowレベル(“0”用紙有り)
の場合は、夫々出力E2はLowレベル(“0″)とな
り,検知遅れがないことを示す.まず、用紙6の検知遅
れのカウント動作は、第3図(a)に示すように、前記
第1図の排他的論理和回路9で検知遅れ有りの出力E2
(Highレベル“1”)があると(SXのYES),
検知遅れのフラグセット(S2)、検知遅れカウンタの
インクリメント(S,)及び該検知遅れカウンタのカウ
ント値を検知遅れレジスタにストアする(S,)勿論、
用紙の検知遅れがなければ(StのNo)、検知遅れフ
ラグセット(S,)、検知遅れカウンタはリセット(S
6)される.
また、この場合の給紙搬送は、第3図(b)に示?よう
にフィードフラグ= 1 (S1)の状態で検知遅れが
あれば(S1。)(検知遅れフラグ=1),その遅れ時
間分,各給紙モータ,給紙クラッチ,搬送クラッチの設
定値を遅くする(S4,のT1=ON時間,T,=OF
F時間).即ち、フイードカウンタ=Tエ(SZZ)で
モータ,各クラッチをO N < s − s )し,
フイードカウンタ” T2 (’s ? )でモータ,
各クラッチをOFF(S,)する.つまり、゛モータ,
各クラッチの設定値を81■で遅くすることにより給紙
のタイミングが遅くなる.
また、S11では用紙先端の検知遅れに応じて、給紙タ
イミングを変えているので常に紙間を一定に保つことが
できる.
次にプレフィード解除の場合について第4図のフローチ
ャートでのべる.同図(a)において,用紙検知送り有
り(出力E2のH ighレベル゛’1″)と判断され
CSxsのYES)、検知遅れカウンタ値が必要最小紙
間を確保するために許容可能な検知遅れ時間の最大値x
iより大きくなった場合、つまり紙間が必要最小区間・
より小さくなった場合にはプ?フィードを解除(フラグ
をセットSエ.)することとにより追いつきジャムを防
止する.
第4図(b)はプレフィードの用紙の長さと給紙クラッ
チのON/OFF動作の関係を示し,フィードフラグ=
1 (s!3)で、フイード解除フラグ=1(S■)
でない状態であって,ブレフイードカウンタ=T,(S
■)のとき、用紙の長さがプレフィード用紙基準値Z,
より小さい場合(SaS)はプレフィードを行い給紙ク
ラッチをONする(S2,).また、プレフィードカウ
ンターT,(S,。)のとき、給紙クラッチをO F
F t,(s.x).プレフイードクラッチをリセット
する(S−Z)−第2図は本発明の他の実施例の回路構
成図を示し、2個の反射型ホトセンサ5,5′を用い,
夫々第1,第2の比較器7,8の一方の入力端子(一)
に入力した場合である.これは,用紙有無の検知と、検
知遅れを専用のセンサ5,5′で検知するので、精度が
高く、円滑な給紙を行うことができる.
(発明の効果)
以上説明したように本発明は、2つの異なる基準値を有
する2つの比較器は、用紙からの反射光量を反射型ホト
センサから入力して用紙搬送経路内における用紙の有無
を検知する信号(E8)と,検知の遅れを示す信号(E
,)によって、反射型ホトセンサと搬送給紙される用紙
との距離にバラッキがあっても、用紙の有無や検知の遅
れを確実に検知できる.したがって、用紙先端の検知遅
れ時間に応じて給紙タイミングを変更し、紙間を常に一
定に保つことができる.また,紙間が必要最小以下の値
になった場合には,プレフィードを行ねないので追いつ
きジャムを防止することができる.For example, if the paper is at the maximum position dmax(
distance d') and the standard position [dave (distance d),
The output E■ of the first comparator 7 is at a low level (11 0
'F paper present), the output E2' of the second comparator 8 is High.
In the case of h level ("1 '" paper leading edge missing), output E2 becomes high level ("1"), indicating that there is a detection delay. On the other hand, if there is no paper and both comparators 7 and 8 are at High level (“1” no paper), or if the paper 6 is in the standard position da
ve, and is detected by the first comparator 7,
Both comparators 7 and 8 are at low level (“0” paper present)
In each case, the output E2 becomes a low level (“0”), indicating that there is no detection delay. First, as shown in FIG. 3(a), the counting operation of the detection delay of the paper 6 is performed by the exclusive OR circuit 9 of FIG.
If there is (High level “1”) (YES in SX),
Set the detection delay flag (S2), increment the detection delay counter (S,), and store the count value of the detection delay counter in the detection delay register (S,).
If there is no paper detection delay (No in St), the detection delay flag is set (S,) and the detection delay counter is reset (S,).
6) To be done. Also, the paper feeding and conveyance in this case is shown in FIG. 3(b). If there is a detection delay in the state of feed flag = 1 (S1) (S1.) (detection delay flag = 1), the setting values of each paper feed motor, paper feed clutch, and transport clutch are delayed by the delay time. (T1=ON time of S4, T,=OF
F time). That is, the motor and each clutch are turned on with the feed counter = T (SZZ) (N < s - s),
Feed counter" T2 ('s?) motor,
Turn each clutch OFF (S,). In other words, ゛motor,
By slowing down the set value of each clutch to 81■, the timing of paper feeding will be delayed. Furthermore, in S11, the paper feeding timing is changed according to the detection delay of the leading edge of the paper, so that the paper spacing can always be kept constant. Next, the case of canceling prefeed will be described using the flowchart in Figure 4. In the same figure (a), it is determined that paper is detected and fed (High level of output E2 is ``1'' and CSxs is YES), and the detection delay counter value is an allowable detection delay to ensure the minimum required paper spacing. maximum time x
If it becomes larger than i, that is, the paper interval is the minimum required interval.
What if it gets smaller? Catch-up jams can be prevented by canceling the feed (setting the flag S.). Figure 4(b) shows the relationship between the pre-feed paper length and the ON/OFF operation of the paper feed clutch, and the feed flag =
1 (s!3), feed cancellation flag = 1 (S■)
is not a state, and the breech counter = T, (S
■) When the paper length is the prefeed paper standard value Z,
If it is smaller (SaS), prefeed is performed and the paper feed clutch is turned on (S2,). Also, when the prefeed counter is T, (S,.), the paper feed clutch is turned OFF.
F t, (s.x). Resetting the pre-feed clutch (S-Z) - Fig. 2 shows a circuit diagram of another embodiment of the present invention, in which two reflective photosensors 5, 5' are used,
One input terminal (1) of the first and second comparators 7 and 8, respectively
This is the case when inputting . This detects the presence or absence of paper and detects the detection delay using dedicated sensors 5 and 5', allowing for highly accurate and smooth paper feeding. (Effects of the Invention) As described above, in the present invention, two comparators having two different reference values input the amount of reflected light from the paper from a reflective photosensor to detect the presence or absence of paper in the paper transport path. signal (E8) indicating a detection delay and a signal (E8) indicating a detection delay.
, ), it is possible to reliably detect the presence or absence of paper and the delay in detection even if there are variations in the distance between the reflective photo sensor and the paper being transported and fed. Therefore, the paper feeding timing can be changed according to the detection delay time of the leading edge of the paper, and the paper spacing can always be kept constant. Additionally, if the paper spacing falls below the required minimum value, prefeeding will not be performed, thereby preventing catch-up jams.
第1図および第2図は本発明の各実施例の回路構成図、
第3図は本実施例の給紙タイミングを変える場合のフロ
ーチャート、第4図は本実施例のプレフィード解除の場
合のフローチャート、第5図および第6図は用紙の搬送
経路の各例のレイアウト図、第7図および第8図は前記
第5図および第6図における反射型ホトセンサの出力波
形図と?基準電圧vA,vl,vcの関係を示す図、第
9図は反射型ホトセンサと用紙の距離dおよび反射型ホ
トセンサ(コレクタ電流工c)の特性グラフを示す図で
ある.
1.2 ・・・搬送ローラ、 3,4 ・・・ガイド板
、 5,5′ ・・・反射型ホトセンサ、51・・・発
光ダイオード(LED)、52・・・ホトトランジスタ
, 6・・・用紙、 7・・・・第1の比較器(出力E
■)、 8 ・・・第2の比較器(出力E,’).
9 ・・・排他的論理和(EX−OR)回路(出力E
2)、10・・・基準電圧源VB、11・・・基準電圧
源vc.第2図
特許出願人 株式会社 リ コ ー
第
図
第
図
《0》
第
図
第
図
第
ア
図
碕閉T
第
図
第
図
組炊ば距kd(mm)1 and 2 are circuit configuration diagrams of each embodiment of the present invention,
Fig. 3 is a flowchart for changing the paper feeding timing in this embodiment, Fig. 4 is a flowchart for canceling prefeed in this embodiment, and Figs. 5 and 6 are layouts of each example of the paper conveyance path. 7 and 8 are the output waveform diagrams of the reflective photosensor in FIGS. 5 and 6, respectively. FIG. 9 is a diagram showing the relationship between the reference voltages vA, vl, and vc, and a graph showing the distance d between the reflective photosensor and paper and the characteristic graph of the reflective photosensor (collector current c). 1.2...Conveyance roller, 3,4...Guide plate, 5,5'...Reflection type photo sensor, 51...Light emitting diode (LED), 52...Phototransistor, 6... paper, 7...first comparator (output E
■), 8...Second comparator (output E,').
9...Exclusive OR (EX-OR) circuit (output E
2), 10... Reference voltage source VB, 11... Reference voltage source vc. Figure 2 Patent Applicant: Ricoh Co., Ltd. (0)
Claims (1)
受光素子出力を夫々一方の入力とする、予め通紙する用
紙中、最も反射率の小さい用紙で、かつ該用紙が前記受
光素子との距離において、最も安定搬送されたときの該
受光素子出力にマージンを含めた基準電圧V_Bを他方
の入力とした第1の比較器と、前記最も反射率の小さい
用紙がガイド板に沿って前記受光素子から、最も離れた
距離のときの該受光出力を有する基準電圧V_Cを他方
の入力とした第2の比較器と、前記第1、第2の比較器
出力を入力として用紙先端検知の遅れを検出する排他的
論理和回路とで構成され、前記遅れ時間に対応して予備
給紙した用紙の給紙タイミングを変化させることを特徴
とする用紙検知装置。A light-receiving element that receives the amount of reflected light from the paper that is being passed, and a light-receiving element that receives the output of the light-receiving element as one of its inputs. A first comparator whose other input is a reference voltage V_B which is the output of the light receiving element including a margin when the paper is transported most stably at a distance from a second comparator whose other input is a reference voltage V_C having the light reception output at the farthest distance from the light receiving element; and a paper leading edge detection circuit whose inputs are the outputs of the first and second comparators. What is claimed is: 1. A paper detection device comprising an exclusive OR circuit for detecting a delay, and changing the paper feeding timing of pre-fed paper in accordance with the delay time.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP1050129A JPH02231344A (en) | 1989-03-03 | 1989-03-03 | Paper form detecting device |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP1050129A JPH02231344A (en) | 1989-03-03 | 1989-03-03 | Paper form detecting device |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH02231344A true JPH02231344A (en) | 1990-09-13 |
Family
ID=12850526
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP1050129A Pending JPH02231344A (en) | 1989-03-03 | 1989-03-03 | Paper form detecting device |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH02231344A (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2006289883A (en) * | 2005-04-14 | 2006-10-26 | Funai Electric Co Ltd | Image forming apparatus |
US7317544B2 (en) * | 2000-12-28 | 2008-01-08 | Canon Kabushiki Kaisha | Image processing apparatus outputting a timing signal, and controlling method for the same |
JP2008083577A (en) * | 2006-09-28 | 2008-04-10 | Oki Data Corp | Image forming apparatus |
-
1989
- 1989-03-03 JP JP1050129A patent/JPH02231344A/en active Pending
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7317544B2 (en) * | 2000-12-28 | 2008-01-08 | Canon Kabushiki Kaisha | Image processing apparatus outputting a timing signal, and controlling method for the same |
JP2006289883A (en) * | 2005-04-14 | 2006-10-26 | Funai Electric Co Ltd | Image forming apparatus |
JP4661318B2 (en) * | 2005-04-14 | 2011-03-30 | 船井電機株式会社 | Image forming apparatus |
JP2008083577A (en) * | 2006-09-28 | 2008-04-10 | Oki Data Corp | Image forming apparatus |
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