JP2010054890A - Image forming apparatus - Google Patents

Image forming apparatus Download PDF

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JP2010054890A
JP2010054890A JP2008220873A JP2008220873A JP2010054890A JP 2010054890 A JP2010054890 A JP 2010054890A JP 2008220873 A JP2008220873 A JP 2008220873A JP 2008220873 A JP2008220873 A JP 2008220873A JP 2010054890 A JP2010054890 A JP 2010054890A
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toner
image
density
control circuit
image density
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JP5331414B2 (en
JP2010054890A5 (en
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Hiroaki Moriyama
浩明 森山
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Kyocera Document Solutions Inc
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Kyocera Mita Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device that suppresses image defects without decreasing performance than is necessary. <P>SOLUTION: The image forming apparatus includes: a toner concentration sensor 30 that detects the concentration of toner at a toner/carrier mixing ratio in two-component developer stored in a developing unit; an image density sensor 33 that detects a quantity of toner (image density) of a toner image transferred to an intermediate transfer belt 8; an exposure device 23 that calculates the proportion of the print of an output image transferred to the intermediate transfer belt 8; and a control circuit 31 that makes the image density sensor 33 detect the image density of a detection patch transferred to the intermediate transfer belt 8, varies a set value for the toner concentration of the two-component developer according to the detected image density, increases a paper interval as the calculated proportion of the print increases, and shortens the paper interval when the toner concentration detected by the toner concentration sensor 30 is high. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

本発明は、電子写真方式を利用した複写機・プリンタ・ファクシミリ或いはこれらを機能的に備えた複合機等の画像形成装置に搭載され、特に、磁性キャリアを用いて非磁性のトナーを帯電させる２成分現像剤を収納した現像器を備えた現像装置に関する。   The present invention is mounted on an image forming apparatus such as a copying machine, a printer, a facsimile using an electrophotographic system, or a multifunction machine functionally equipped with these, and in particular, a non-magnetic toner is charged using a magnetic carrier 2. The present invention relates to a developing device provided with a developing device containing a component developer.

従来から、複数枚の転写紙に対して連続して画像形成処理を行う場合に、出力画像のドット数をドットカウンタで算出し、出力画像のドット数が閾値よりも多い場合には、転写紙の給紙間隔を長くするようにした２成分現像方式の現像増装置を搭載した画像形成装置が知られている（例えば、特許文献１参照）。   Conventionally, when image formation processing is continuously performed on a plurality of transfer sheets, the number of dots in the output image is calculated by a dot counter, and if the number of dots in the output image is greater than the threshold value, the transfer sheet There is known an image forming apparatus equipped with a two-component development type development increasing device in which the paper feeding interval is increased (see, for example, Patent Document 1).

これは、出力画像が高濃度印字の場合に、画像形成処理時の給紙間隔を長くすると共に現像器内での二成分現像剤の攪拌時間を長くすることによって、現像器中のトナーの入れ替わりを促進し得て、像担持体に転写する際の二成分現像剤が不均一となってしまったり帯電量が低下してしまうことを防止することができる。   This is because when the output image is high density printing, the toner in the developing unit is replaced by increasing the paper feeding interval during the image forming process and increasing the stirring time of the two-component developer in the developing unit. It is possible to prevent the two-component developer at the time of transferring to the image carrier from becoming non-uniform and the charge amount from being reduced.

尚、長期間にわたって現像剤の帯電量を安定化させるため、中間転写体や感光体等の像担持体上に一定条件にて形成した画像濃度検出用パッチ画像の画像濃度を画像濃度センサで読み取り、その出力値によって現像剤のトナー濃度の設定値を可変することは周知である。
特開平０１−０１５７７２号公報 In order to stabilize the charge amount of the developer over a long period of time, the image density sensor reads the image density of the image density detection patch image formed on the image bearing member such as an intermediate transfer member or the photosensitive member under a certain condition. It is well known that the set value of the toner density of the developer is varied depending on the output value.
JP-A-01-015772

ところが、上記の如く構成された現像装置にあっては、二成分現像剤のトナー濃度が高く設定されているときには二成分現像剤の帯電量も高いため、給紙間隔を長くして攪拌時間を長くしただけでは逆効果となり画像濃度低下等の不具合を発生させてしまうという問題が生じていた。また、給紙間隔を長くすると、画像処理能力が低下してしまうという問題も生じていた。   However, in the developing device configured as described above, when the toner concentration of the two-component developer is set high, the charge amount of the two-component developer is also high. If the length is increased, the effect is reversed, causing problems such as a decrease in image density. In addition, when the paper feed interval is increased, there is a problem that the image processing capability is reduced.

そこで、本発明は、上記事情を考慮し、必要以上にパフォーマンスを低下させることなく画像欠陥の発生を抑制することができる現像装置を提供することを目的とする。   In view of the above circumstances, an object of the present invention is to provide a developing device that can suppress the occurrence of image defects without degrading performance more than necessary.

本発明の画像形成装置は、現像器内に収納された二成分現像剤中のトナーとキャリアとの混合比からなるトナー濃度を検出するトナー濃度センサと、像担持体上に転写されたトナー量を検出する画像濃度センサと、前記像担持体上に転写される出力画像の印字率を算出する演算部と、前記像担持体上に転写された検出用パッチの画像濃度を前記画像濃度センサで検出させ且つその検出画像濃度によって前記現像器内に収納された二成分現像剤のトナー濃度の設定値を可変する制御回路と、を備えた現像装置において、前記制御回路は、前記演算部で算出された印字率が高くなるにつれて給紙間隔を長くすると共に、前記トナー濃度センサで検出されたトナー濃度が高い場合には給紙間隔を短くすることを特徴とする。   An image forming apparatus according to the present invention includes a toner concentration sensor that detects a toner concentration including a mixing ratio of toner and carrier in a two-component developer housed in a developing device, and an amount of toner transferred onto an image carrier. An image density sensor for detecting an image, a calculation unit for calculating a printing rate of an output image transferred onto the image carrier, and an image density sensor for determining an image density of a detection patch transferred onto the image carrier. And a control circuit configured to vary a toner density setting value of the two-component developer stored in the developing device according to the detected image density. The paper feeding interval is lengthened as the printed rate increases, and the paper feeding interval is shortened when the toner density detected by the toner density sensor is high.

この際、前記制御回路は、前記トナー濃度センサで検出されたトナー濃度値について、複数の閾値を設け、トナー濃度が高くなるにつれて段階的に給紙間隔を短くするのが好ましい。   At this time, it is preferable that the control circuit provides a plurality of threshold values for the toner density value detected by the toner density sensor, and gradually shortens the paper feed interval as the toner density increases.

本発明の画像形成装置は、必要以上にパフォーマンスを低下させることなく画像欠陥の発生を抑制することができる。   The image forming apparatus of the present invention can suppress the occurrence of image defects without degrading performance more than necessary.

次に、本発明の一実施形態に係る画像形成装置について、図面を参照して説明する。   Next, an image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings.

図１は本発明の一実施形態に係る画像形成装置としてのプリンタの説明図、図２は本発明の一実施形態に係る画像形成装置の要部の説明図である。   FIG. 1 is an explanatory diagram of a printer as an image forming apparatus according to an embodiment of the present invention. FIG. 2 is an explanatory diagram of a main part of the image forming apparatus according to an embodiment of the present invention.

（カラープリンタ１の全体構成）税理士
図１において、本発明の一実施形態に係る画像形成装置としてのカラープリンタ１は、プリンタ本体２の一面（例えば、正面）から引き出し可能な給紙カセット３と、プリンタ本体２の一面に起倒可能に設けられた手差し給紙トレイ４と、給紙カセット３又は手差し給紙トレイ４にセットされた転写紙（図示せず）を搬送する搬送経路５と、搬送経路５の上流端を構成する給紙ユニット部６と、搬送経路５の中途部に配置された二次転写ローラ７と、二次転写ローラ７と協働して転写紙の表面にトナー転写像を形成する無端ベルト状の中間転写ベルト８と、中間転写ベルト８の表面に必要に応じた各色（例えば、イエロー（Ｙ）・マゼンダ（Ｍ）・シアン（Ｃ）・ブラック（Ｋ））のトナーをトナー像として転写する複数の画像形成部９と、搬送経路５の終端寄りに配置されて転写紙の表面に形成されたトナー転写像を定着させる定着ユニット１０と、定着後の転写紙を搬送経路５の下流端からプリンタ本体２の排紙トレイ部１１へと排出する排出部１２とを備えている。 (Overall Configuration of Color Printer 1) Tax Accountant In FIG. 1, a color printer 1 as an image forming apparatus according to an embodiment of the present invention includes a paper feed cassette 3 that can be pulled out from one surface (for example, the front surface) of a printer body 2. A manual feed tray 4 provided on one surface of the printer main body 2 so as to be able to rise and fall, a transport path 5 for transporting a transfer sheet (not shown) set in the paper feed cassette 3 or the manual feed tray 4, Toner transfer onto the surface of the transfer paper in cooperation with the paper feed unit 6 constituting the upstream end of the transport path 5, the secondary transfer roller 7 disposed in the middle of the transport path 5, and the secondary transfer roller 7 An endless belt-shaped intermediate transfer belt 8 for forming an image, and various colors (for example, yellow (Y), magenta (M), cyan (C), and black (K)) as necessary on the surface of the intermediate transfer belt 8 Toner image As a plurality of image forming units 9, a fixing unit 10 that is disposed near the end of the conveyance path 5 and fixes a toner transfer image formed on the surface of the transfer paper, and a fixed transfer paper on the conveyance path 5. A discharge section 12 that discharges from the downstream end to the discharge tray section 11 of the printer main body 2 is provided.

中間転写ベルト８は、像担持体としての機能を具備しており、層構成に少なくとも一層の弾性層を用いた弾性中間転写ベルトが採用され、駆動ローラ１３、従動ローラ（テンションローラ）１４、加圧ローラ１５の間で回動移動（図示矢印参照）する。   The intermediate transfer belt 8 has a function as an image carrier, and an elastic intermediate transfer belt using at least one elastic layer is adopted for the layer structure, and includes a driving roller 13, a driven roller (tension roller) 14, an additional roller. Rotating movement between the pressure rollers 15 (see the arrow in the figure).

加圧ローラ１５は中間転写ベルト８を挟んで二次転写ローラ７と対向配置されており、二次転写ローラ７に転写バイアスを印加することによって搬送経路５に搬送された転写紙の表面にトナー像を転写してトナー転写像を形成する。   The pressure roller 15 is disposed opposite to the secondary transfer roller 7 with the intermediate transfer belt 8 interposed therebetween, and the toner is applied to the surface of the transfer paper conveyed to the conveyance path 5 by applying a transfer bias to the secondary transfer roller 7. The image is transferred to form a toner transfer image.

（画像形成部９の構成）
画像形成部９は、本実施の形態では中間転写ベルト８の回動移動方向に沿ってタンデム方式で４ヶ所に配置され、実質的に同一構成のものが配置されている。また、画像形成部９は、各色のトナーを収納したトナーコンテナ１６と、トナーコンテナ１６に収納したトナーを供給する供給部１７と、表面に供給部１７からトナーが供給されるドラム状の静電潜像担持体としての感光体１８と、中間転写ベルト８を挟んで感光体１８に対向配置された転写ローラ１９と、感光体１８の表面に付着した残存トナー等を除去するクリーニングデバイス２０と、感光体１８の電荷を除去する除電デバイス２１と、感光体１８の表面を帯電する帯電デバイス２２と、感光体１８の表面に所定の静電潜像を形成する露光デバイス２３と、を備えている。 (Configuration of the image forming unit 9)
In the present embodiment, the image forming units 9 are arranged at four locations in a tandem manner along the rotational movement direction of the intermediate transfer belt 8, and those having substantially the same configuration are arranged. In addition, the image forming unit 9 includes a toner container 16 that stores toner of each color, a supply unit 17 that supplies toner stored in the toner container 16, and a drum-like electrostatic that is supplied with toner from the supply unit 17 on the surface. A photosensitive member 18 as a latent image carrier, a transfer roller 19 disposed opposite to the photosensitive member 18 with the intermediate transfer belt 8 interposed therebetween, a cleaning device 20 for removing residual toner and the like adhering to the surface of the photosensitive member 18, and A neutralization device 21 that removes the electric charge of the photoconductor 18, a charging device 22 that charges the surface of the photoconductor 18, and an exposure device 23 that forms a predetermined electrostatic latent image on the surface of the photoconductor 18 are provided. .

尚、各画像形成部９は、本実施の形態では、中間転写ベルト８の回動移動方向に沿ってマゼンダ用の画像形成部９（Ｍ）、シアン用の画像形成部９（Ｃ）、イエロー用の画像形成部９（Ｙ）の順で配置され、図示右側の端部にブラック用の画像形成部９（Ｋ）が配置されている。   In the present embodiment, each image forming unit 9 includes a magenta image forming unit 9 (M), a cyan image forming unit 9 (C), and a yellow along the rotational movement direction of the intermediate transfer belt 8. The image forming unit 9 (Y) for black is arranged in this order, and the image forming unit 9 (K) for black is arranged at the right end in the figure.

（供給部１７の構成）
供給部１７は、図２に示すように、トナーコンテナ１６から供給されたトナーとキャリアとからなる二成分現像剤を撹拌・帯電する撹拌ミキサー２４と、撹拌ミキサー２４から供給された二成分現像剤を撹拌・搬送するパドルミキサー２５と、各ミキサー２４，２５の間に介在された仕切板２６と、内部に複数の固定磁石を配設してその周囲を回転可能としたスリーブ状の現像剤担持体としての磁気ローラ２７と、磁気ローラ２７上に形成された磁気ブラシ（図示せず）によってトナー層（図示せず）を形成するトナー担持体としての現像ローラ２８と、磁気ローラ２７上に形成された磁気ブラシの高さを一定に保つための規制ブレード２９と、を備えている。また、供給部１７は、トナーコンテナ１６から供給されて攪拌ミキサー２４で攪拌・帯電される二成分現像剤のトナー（Ｔ）とキャリア（Ｃ）との重量比（Ｔ／Ｃ）をトナー濃度として検出するトナー濃度センサ３０を備えている。この際、トナー濃度センサ３０によって検出されたトナー濃度は、制御回路３１に出力される。 (Configuration of supply unit 17)
As shown in FIG. 2, the supply unit 17 includes a stirring mixer 24 that stirs and charges the two-component developer composed of toner and carrier supplied from the toner container 16, and a two-component developer supplied from the stirring mixer 24. A paddle mixer 25 that stirs and conveys, a partition plate 26 interposed between the mixers 24, 25, and a sleeve-like developer bearing that has a plurality of fixed magnets disposed therein and is rotatable around the periphery. A magnetic roller 27 as a body, a developing roller 28 as a toner carrier for forming a toner layer (not shown) by a magnetic brush (not shown) formed on the magnetic roller 27, and formed on the magnetic roller 27. And a regulating blade 29 for keeping the height of the magnetic brush constant. Further, the supply unit 17 uses the weight ratio (T / C) of the toner (T) and carrier (C) of the two-component developer supplied from the toner container 16 and stirred and charged by the stirring mixer 24 as the toner concentration. A toner density sensor 30 for detection is provided. At this time, the toner density detected by the toner density sensor 30 is output to the control circuit 31.

（制御回路３１）
制御回路３１は、ＲＯＭ３２に格納された画像形成処理に関する制御プログラムに基づいて供給部１７の駆動系等を制御する。また、制御回路３１には、例えば、図示を略するパーソナルコンピュータから出力された印刷データに基づく印字率が露光デバイス２３等の画像処理回路や公知のドットカウンタ（共に図示せず）等から入力されると共に、供給部１７から中間転写ベルト８に転写されたトナー像の画像濃度が画像濃度センサ３３から入力される。また、ＲＯＭ３２には、本発明に係わる給紙間隔制御プログラムも格納されており、露光デバイス２３等から出力された印字率、トナー濃度センサ３０から出力されたトナー濃度、画像濃度センサ３３から出力された画像濃度に基づいて、給紙ユニット部６を駆動する駆動部３４の駆動タイミングを制御回路３１が制御して、転写紙の給紙間隔を変更する。 (Control circuit 31)
The control circuit 31 controls the drive system and the like of the supply unit 17 based on a control program related to image formation processing stored in the ROM 32. Further, for example, a printing rate based on print data output from a personal computer (not shown) is input to the control circuit 31 from an image processing circuit such as the exposure device 23 or a known dot counter (both not shown). In addition, the image density of the toner image transferred from the supply unit 17 to the intermediate transfer belt 8 is input from the image density sensor 33. The ROM 32 also stores a paper feed interval control program according to the present invention. The printing rate output from the exposure device 23 and the like, the toner density output from the toner density sensor 30, and the image density sensor 33 are output. Based on the image density, the control circuit 31 controls the drive timing of the drive unit 34 that drives the paper feed unit 6 to change the transfer paper feed interval.

（画像濃度センサ３３）
画像濃度センサ３３は、図３に示すように、ＬＥＤ等の光源３５から出射されたビーム光束がビームスプリッタ３６を透過して中間転写ベルト８のトナー面（トナー像）に照射される。また、ビームスプリッタ３６に偏向されたビーム光束が受光センサ３７にてモニターされ、光源３５の光量を一定に保つように構成されている。 (Image density sensor 33)
As shown in FIG. 3, in the image density sensor 33, a beam beam emitted from a light source 35 such as an LED passes through a beam splitter 36 and is irradiated onto a toner surface (toner image) of the intermediate transfer belt 8. Further, the light beam deflected by the beam splitter 36 is monitored by the light receiving sensor 37, and the light quantity of the light source 35 is kept constant.

一方、トナー面から反射した反射光束は散乱光となり、ビームスプリッタ３８にて再び２つの偏光成分に分配され、それぞれ受光センサ３９，４０に入射され、各受光センサ３９，４０に受光された光量の比率によってトナー量（画像濃度）を検知する。   On the other hand, the reflected light beam reflected from the toner surface becomes scattered light, and is again divided into two polarized light components by the beam splitter 38 and is incident on the light receiving sensors 39 and 40, respectively. The toner amount (image density) is detected based on the ratio.

（画像形成処理）
このような構成のカラープリンタ１においては、図示を略すパーソナルコンピュータ等から印刷データが出力されると、帯電デバイス２２によって感光体１８の表面が帯電された後（帯電工程）、露光デバイス２３によって感光体１８の表面が露光されて静電潜像が形成される（露光工程）。 (Image formation processing)
In the color printer 1 having such a configuration, when print data is output from a personal computer (not shown) or the like, the surface of the photoconductor 18 is charged by the charging device 22 (charging process), and then exposed by the exposure device 23. The surface of the body 18 is exposed to form an electrostatic latent image (exposure process).

一方、供給部１７においては、二成分現像剤が磁気ローラ２７の表面に担持されて磁気ブラシを形成し、その磁気ローラ２７の表面の磁気ブラシからトナーのみを現像ローラ２８の表面に移送させて現像ローラ２８の表面にトナー層を形成する。   On the other hand, in the supply unit 17, the two-component developer is carried on the surface of the magnetic roller 27 to form a magnetic brush, and only the toner is transferred from the magnetic brush on the surface of the magnetic roller 27 to the surface of the developing roller 28. A toner layer is formed on the surface of the developing roller 28.

さらに、この現像ローラ２８のトナー層からトナーを飛翔させ、感光体１８の静電潜像にトナーを付着させて静電潜像をトナー像として現像した後（現像工程）、そのトナー像を転写ローラ１９によって感光体１８から中間転写ベルト８へと一次転写する（一次転写工程）。   Further, the toner is ejected from the toner layer of the developing roller 28, and the toner is attached to the electrostatic latent image on the photosensitive member 18 to develop the electrostatic latent image as a toner image (developing process), and then the toner image is transferred. The roller 19 performs primary transfer from the photoreceptor 18 to the intermediate transfer belt 8 (primary transfer process).

次に、中間転写ベルト８に一次転写されたトナー像は、中間転写ベルト８の回動移動によって二次転写ローラ７へと搬送され、この二次転写ローラ７に印加された転写バイアスによって転写紙へと転写される（二次転写工程）。   Next, the toner image primarily transferred to the intermediate transfer belt 8 is conveyed to the secondary transfer roller 7 by the rotational movement of the intermediate transfer belt 8, and the transfer paper is applied by the transfer bias applied to the secondary transfer roller 7. (Secondary transfer process).

尚、二次転写ローラ７によってトナー像を二次転写した後の中間転写ベルト８の表面に残存したトナー等は、二次転写ローラ７よりも回動移動方向下流側に配置されたベルトクリーニング装置４１によって除去される。   The toner remaining on the surface of the intermediate transfer belt 8 after the secondary transfer of the toner image by the secondary transfer roller 7 is arranged on the downstream side of the secondary transfer roller 7 in the rotational movement direction. 41 to remove.

（給紙間隔制御）
次に、本発明の制御回路３１による給紙間隔制御について説明する。 (Feeding interval control)
Next, the paper feed interval control by the control circuit 31 of the present invention will be described.

制御回路３１は、画像印字中に、トナー濃度センサ３０によって二成分現像剤の透磁率に基づくトナー濃度を読み取らせる。   The control circuit 31 causes the toner density sensor 30 to read the toner density based on the magnetic permeability of the two-component developer during image printing.

トナー濃度センサ３０は、トナー濃度が高い場合にはトナー濃度センサ３０の出力電圧は低くなり、トナー濃度が低い場合にはトナー濃度センサ３０の出力電圧は高くなる。   When the toner density is high, the output voltage of the toner density sensor 30 is low, and when the toner density is low, the output voltage of the toner density sensor 30 is high.

この際、制御回路３１は、トナー濃度が予め設定された制御値（例えば、ＲＯＭ３２に格納）よりも低い場合には、印字画像のドットカウント（印字率）によりトナーコンテナ１６からのトナー補給量を算出し、消費されたトナーよりもやや多目の補給を行う。尚、制御回路３１は、トナー濃度が制御値よりも高い場合には補給を行わない。   At this time, when the toner density is lower than a preset control value (for example, stored in the ROM 32), the control circuit 31 determines the toner replenishment amount from the toner container 16 by the dot count (printing rate) of the print image. Calculate and supply a little more than the consumed toner. The control circuit 31 does not replenish when the toner density is higher than the control value.

また、制御回路３１は、例えば、キャリブレーション等の画像濃度検出時に、供給部１７から中間転写ベルト８にパッチ画像を転写し、そのパッチ画像の画像濃度を画像濃度センサ３３にて検出させる。   The control circuit 31 also transfers a patch image from the supply unit 17 to the intermediate transfer belt 8 and detects the image density of the patch image by the image density sensor 33 when detecting the image density such as calibration.

制御回路３１は、キャリブレーション時に画像濃度センサ３３にて読み取った検出用パッチの画像濃度が高い場合には、二成分現像剤の帯電量が低下しているため、二成分現像剤のトナー濃度が低くなるようにトナー濃度制御値を変更する。また、逆に検出用パッチの画像濃度が低い場合には、現像剤の帯電量が上昇しているため、現像剤のトナー濃度が高くなるようにトナー濃度制御値を変更する。   When the image density of the detection patch read by the image density sensor 33 during calibration is high, the control circuit 31 reduces the charge amount of the two-component developer, so that the toner concentration of the two-component developer is reduced. The toner density control value is changed so as to decrease. Conversely, when the image density of the detection patch is low, the charge amount of the developer is increased, so the toner density control value is changed so that the toner density of the developer becomes high.

次に、制御回路３１は、上述した印字率とトナー濃度制御値とにより、給紙間隔を設定する。   Next, the control circuit 31 sets a paper feed interval based on the above-described printing rate and toner density control value.

具体的には、制御回路３１は、印字率が高くなるにつれて給紙間隔が長くなるように駆動部３４を制御し、現像剤のトナー濃度が高い場合には給紙間隔が短くなるように駆動部３４を制御する。   Specifically, the control circuit 31 controls the drive unit 34 so that the paper feed interval becomes longer as the printing rate becomes higher, and is driven so that the paper feed interval becomes shorter when the toner density of the developer is high. The unit 34 is controlled.

図４（Ａ）は本発明に係る制御回路３１による印字率とトナー濃度設定値との関係における給紙間隔制御例の図表、図４（Ｂ）は従来の印字率のみによる給紙間隔制御例（長間隔）の図表、図４（Ｃ）は従来の印字率のみによる給紙間隔制御例（短間隔）の図表である。   FIG. 4A is a chart of an example of sheet feeding interval control in the relationship between the printing rate and the toner density setting value by the control circuit 31 according to the present invention, and FIG. 4B is an example of feeding interval control by the conventional printing rate alone. FIG. 4C is a chart of a feed interval control example (short interval) based only on a conventional printing rate.

図４（Ａ）に示すように、本発明の制御回路３１では、印字率とトナー濃度設定値とに基づいて得られた長さの給紙間隔となるように給紙タイミングを調整するようにした。   As shown in FIG. 4A, the control circuit 31 of the present invention adjusts the paper feed timing so as to obtain a paper feed interval having a length obtained based on the printing rate and the toner density setting value. did.

尚、図４に示した給紙間隔の設定においては、トナー濃度が８％未満、８％以上１１％未満、１１％以上、の場合で段階的にトナー濃度が高い場合に給紙間隔を短くしている。   In the setting of the paper feed interval shown in FIG. 4, when the toner density is less than 8%, 8% or more and less than 11%, or 11% or more, and the toner density is gradually increased, the paper feed interval is shortened. is doing.

一例として、図５に示すように、濃度設定値がそれぞれ７％、９．５％、１２％となるように調整すると共に、印字率が１０％、３０％、５０％、７０％、９０％の画像を３０枚連続印字した時のカブリ等の画像欠陥の発生有無を示す。   As an example, as shown in FIG. 5, the density setting values are adjusted to 7%, 9.5%, and 12%, respectively, and the printing rate is 10%, 30%, 50%, 70%, and 90%. The occurrence of image defects such as fogging when 30 images are continuously printed is shown.

図４（Ｂ），図５（Ｂ）では、画像欠陥が発生しない比較的良好な画像を得ることができたものの、本発明の制御回路３１による給紙間隔が長いため、画像形成処理能力等のパフォーマンスが低下した。   In FIGS. 4B and 5B, although a relatively good image with no image defect can be obtained, the sheet feeding interval by the control circuit 31 of the present invention is long, so that the image forming processing capability, etc. Performance declined.

また、図４（Ｃ），図５（Ｃ）では、トナー濃度設定値が低い場合に給紙間隔が短かすぎるためにカブリ等の画像不具合が発生した。   Further, in FIGS. 4C and 5C, when the toner density setting value is low, an image defect such as fogging occurs because the paper feed interval is too short.

これらに対し、本発明の制御回路３１による給紙間隔制御では、現像剤のトナー濃度が低く印字率が高い条件ほど給紙間隔を長くし、逆に現像剤のトナー濃度が高く印字率が低い条件ほど給紙間隔を短くする制御を行うことにより、必要以上にパフォーマンスを低下させること無く、画像欠陥のない良好な画像を得ることができた。   On the other hand, in the paper feed interval control by the control circuit 31 of the present invention, the paper feed interval is lengthened as the developer toner concentration is low and the printing rate is high. Conversely, the developer toner concentration is high and the printing rate is low. By controlling to shorten the paper feed interval as much as the condition, a good image free from image defects could be obtained without degrading performance more than necessary.

ところで、上記実施の形態においては、トナー濃度設定値を８％未満、８％以上１１％未満、１１％以上、の３段階に分けた場合で示したが、例えば、１０％未満と１０％以上というように、２段階に分けても良いし、４段階以上に分けても良い。   By the way, in the above-described embodiment, the toner density setting value is shown in three stages of less than 8%, 8% or more and less than 11%, and 11% or more, but for example, less than 10% and 10% or more. Thus, it may be divided into two stages, or may be divided into four or more stages.

本発明の一実施形態に係る現像装置を搭載した画像形成装置の説明図である。1 is an explanatory diagram of an image forming apparatus equipped with a developing device according to an embodiment of the present invention. 本発明の一実施形態に係る現像装置の要部の説明図である。It is explanatory drawing of the principal part of the developing device which concerns on one Embodiment of this invention. 本発明の一実施形態に係る現像装置に適用される画像濃度センサの説明図である。It is explanatory drawing of the image density sensor applied to the image development apparatus concerning one Embodiment of this invention. （Ａ）は本発明の一実施形態、（Ｂ），（Ｃ）は従来に係る給紙間隔制御例の一覧の図表である。(A) is an embodiment of the present invention, and (B) and (C) are tables of a list of conventional paper feed interval control examples. （Ａ）は本発明の一実施形態、（Ｂ），（Ｃ）は従来に係る給紙間隔制御例の画像形成結果の図表である。(A) is an embodiment of the present invention, and (B) and (C) are charts of image formation results of a conventional paper feed interval control example.

符号の説明Explanation of symbols

１…カラープリンタ（画像形成装置）
８…中間転写ベルト（像担持体）
９…画像形成部
２３…露光デバイス（演算部）
３０…トナー濃度センサ
３１…制御回路
３３…画像濃度センサ 1. Color printer (image forming device)
8 ... Intermediate transfer belt (image carrier)
9 ... Image forming unit 23 ... Exposure device (calculation unit)
30 ... Toner density sensor 31 ... Control circuit 33 ... Image density sensor

Claims (2)

現像器内に収納された二成分現像剤中のトナーとキャリアとの混合比からなるトナー濃度を検出するトナー濃度センサと、像担持体上に転写されたトナー量を検出する画像濃度センサと、前記像担持体上に転写される出力画像の印字率を算出する演算部と、前記像担持体上に転写された検出用パッチの画像濃度を前記画像濃度センサで検出させ且つその検出画像濃度によって前記現像器内に収納された二成分現像剤のトナー濃度の設定値を可変する制御回路と、を備えた現像装置において、
前記制御回路は、前記演算部で算出された印字率が高くなるにつれて給紙間隔を長くすると共に、前記トナー濃度センサで検出されたトナー濃度が高い場合には給紙間隔を短くすることを特徴とする現像装置。 A toner density sensor for detecting a toner density comprising a mixing ratio of toner and carrier in a two-component developer housed in the developing device, an image density sensor for detecting the amount of toner transferred on the image carrier, An arithmetic unit that calculates a printing rate of an output image transferred onto the image carrier, and an image density sensor that detects the image density of the detection patch transferred onto the image carrier, and the detected image density A developing device comprising: a control circuit that varies a set value of the toner concentration of the two-component developer housed in the developing device;
The control circuit lengthens the paper feed interval as the printing rate calculated by the arithmetic unit increases, and shortens the paper feed interval when the toner density detected by the toner density sensor is high. A developing device. 前記制御回路は、前記トナー濃度センサで検出されたトナー濃度値について、複数の閾値を設け、トナー濃度が高くなるにつれて段階的に給紙間隔を短くすることを特徴とする請求項１に記載の現像装置。   2. The control circuit according to claim 1, wherein the control circuit provides a plurality of threshold values for the toner density value detected by the toner density sensor, and gradually shortens the paper feed interval as the toner density increases. Development device.
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JP2013025062A (en) * 2011-07-21 2013-02-04 Kyocera Document Solutions Inc Image forming apparatus capable of printing long sheet
JP2013213957A (en) * 2012-04-03 2013-10-17 Fuji Xerox Co Ltd Image forming apparatus
JP2017090707A (en) * 2015-11-11 2017-05-25 コニカミノルタ株式会社 Image formation device

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JP2013025062A (en) * 2011-07-21 2013-02-04 Kyocera Document Solutions Inc Image forming apparatus capable of printing long sheet
JP2013213957A (en) * 2012-04-03 2013-10-17 Fuji Xerox Co Ltd Image forming apparatus
JP2017090707A (en) * 2015-11-11 2017-05-25 コニカミノルタ株式会社 Image formation device

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