JP2017138399A - Image forming apparatus - Google Patents

Image forming apparatus Download PDF

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JP2017138399A
JP2017138399A JP2016018069A JP2016018069A JP2017138399A JP 2017138399 A JP2017138399 A JP 2017138399A JP 2016018069 A JP2016018069 A JP 2016018069A JP 2016018069 A JP2016018069 A JP 2016018069A JP 2017138399 A JP2017138399 A JP 2017138399A
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density
control
image forming
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image
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JP6690088B2 (en
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敬典 堤
Takanori Tsutsumi
敬典 堤
雅弘 光崎
Masahiro Mitsuzaki
雅弘 光崎
統成 中野
Munenori Nakano
統成 中野
裕紀 赤司
Hironori Akashi
裕紀 赤司
謙治 鶴
Kenji Tsuru
謙治 鶴
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Konica Minolta Inc
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Abstract

PROBLEM TO BE SOLVED: To accurately determine the most desirable gradation of a test pattern used in maximum density state detection control.SOLUTION: There is provided an image forming apparatus comprising: image forming means that forms a toner image on an image carrier; detection means that optically detects the density of the toner image formed on the image carrier; and control means that controls the operation of the image forming means. The control means executes state detection control of forming, with toner, a control pattern consisting of a plurality of density standards on the image carrier (step S11), estimating a variation in maximum density according to the limit of density detection performed by the detection means with the control pattern, and determining the gradation of the test pattern (step S15). The control means further forms the test pattern on the image carrier with the determined gradation, and executes maximum density state detection control according to a result of density detection performed by the detection means with the test pattern.SELECTED DRAWING: Figure 4

Description

本発明は、画像形成装置、特に、画像安定化制御を行う電子写真方式による画像形成装置に関する。   The present invention relates to an image forming apparatus, and more particularly to an electrophotographic image forming apparatus that performs image stabilization control.

一般に、電子写真方式による複写機やプリンタなどの画像形成装置においては、感光体の感光特性や現像剤の帯電量の変化などに起因して出力画像の濃度が安定しないという問題がある。このような画像品質の劣化を防止するために、個々の画像形成装置においては、印字動作の前や印字動作中に像担持体上に所定の作像条件でトナーによるテストパターンを形成し、該テストパターンの濃度を光学的に検出し、その結果を帯電電圧や現像バイアス電圧、露光光量などの作像条件、入出力画像データ特性（ガンマ補正データ）などにフィードバックしている（例えば、特許文献１参照）。この種のフィードバック制御は画像安定化制御と称され、主に最大濃度、中間調濃度、線幅（ドット径）を維持している。   In general, in an electrophotographic image forming apparatus such as a copying machine or a printer, there is a problem that the density of an output image is not stable due to a change in photosensitive characteristics of a photosensitive member or a charge amount of a developer. In order to prevent such deterioration of image quality, each image forming apparatus forms a test pattern with toner on the image carrier under a predetermined image forming condition before or during the printing operation. The density of the test pattern is optically detected, and the result is fed back to image forming conditions such as charging voltage, developing bias voltage, exposure light quantity, and input / output image data characteristics (gamma correction data). 1). This type of feedback control is called image stabilization control, and mainly maintains maximum density, halftone density, and line width (dot diameter).

画像安定化制御を実行する場合、印字動作の中断によってプリント生産性が低下するのを極力回避するため、印字動作の前や連続印字動作中であって用紙が作像部に送り込まれていないときに画像濃度の状態を検出する状態検出制御を実行している。状態検出制御では画像安定化制御時に形成するテストパターンよりも短いテストパターン（以下、画像安定化制御のテストパターンと区別するために制御パターンと称する）を像担持体上に形成し、光学センサによるその濃度検出結果に基づいて印字される画像濃度が所定範囲内にあるか否かを判断し、画像安定化制御実行の可否を判断する制御が知られている。状態検出制御では、最大濃度、中間調濃度、線再現性などの品質を確認するためにそれぞれに適した制御パターンを形成している。   When executing image stabilization control, to avoid printing productivity degradation due to interruption of printing operation as much as possible, before printing operation or during continuous printing operation, when paper is not sent to the image forming unit In addition, state detection control for detecting the state of image density is executed. In the state detection control, a test pattern shorter than the test pattern formed at the time of image stabilization control (hereinafter referred to as a control pattern for distinguishing from the test pattern for image stabilization control) is formed on the image carrier, and the optical sensor is used. There is known control for determining whether or not the image density to be printed is within a predetermined range based on the density detection result and determining whether or not the image stabilization control can be executed. In the state detection control, control patterns suitable for each quality are formed in order to confirm the quality such as maximum density, halftone density, and line reproducibility.

特開２００９−２１７１６３号公報JP 2009-217163 A

ところで、トナー像の濃度を検出する手段（光学センサ）は、高濃度領域での検出ができないという問題点を有している。光学センサによる濃度の検出は、トナーが付着していない領域では光がほぼ全反射し、トナーが付着している領域では一部の光がトナーに吸収されて反射光が少なくなる現象を利用している。光学センサによるトナー付着量検出特性は、図８に示すように、付着量の増加に伴ってセンサ出力値が低下することになる。つまり、光学センサはテストパターンの色や付着量の絶対値を測定している訳ではなく、トナーの付着量の増加に伴って変化する隠蔽率の変化を付着量の代用特性として検出している。それゆえ、図８に示す高濃度領域Ｘでは検出感度が低下し、濃度を正確に検出することができない。   Incidentally, the means (optical sensor) for detecting the density of the toner image has a problem that it cannot be detected in a high density region. The density detection by the optical sensor uses the phenomenon that light is almost totally reflected in the area where the toner is not attached, and part of the light is absorbed by the toner and the reflected light is reduced in the area where the toner is attached. ing. As shown in FIG. 8, in the toner adhesion amount detection characteristic by the optical sensor, the sensor output value decreases as the adhesion amount increases. In other words, the optical sensor does not measure the color of the test pattern or the absolute value of the adhesion amount, but detects a change in the concealment ratio that changes as the adhesion amount of the toner increases as a substitute characteristic of the adhesion amount. . Therefore, the detection sensitivity decreases in the high concentration region X shown in FIG. 8, and the concentration cannot be accurately detected.

画像安定化制御における最大濃度制御では、図９に示すように、現像バイアス電圧に対してトナー付着量がリニアに変化する特性を利用し、光学センサが直接検出的ない最大濃度を制御している。   In the maximum density control in the image stabilization control, as shown in FIG. 9, the optical sensor controls the maximum density that is not directly detected by using the characteristic that the toner adhesion amount changes linearly with respect to the developing bias voltage. .

最大濃度の状態検出制御では、テストパターンを最大濃度で形成し、最大濃度状態を検出する方法が最も単純かつ容易である。しかし、光学センサの検出感度が低くて最大濃度を検出できないため、最大濃度より低い濃度となる階調でパターンを形成し、最大濃度の状態を予測する必要がある。最大濃度の状態を予測するために、制御精度の観点では光学センサが検出可能な範囲において極力高濃度でテストパターンを形成し、その濃度を検出する必要がある。つまり、図１０に示すように、最大濃度の変動に伴う中間調濃度の変動は、高濃度部（高階調）のほうが大きい。濃度変化を検出可能な階調に設定するのが望ましい。   In the maximum density state detection control, the simplest and easiest method is to form a test pattern with the maximum density and detect the maximum density state. However, since the detection sensitivity of the optical sensor is low and the maximum density cannot be detected, it is necessary to form a pattern with gradations having a density lower than the maximum density and predict the state of the maximum density. In order to predict the state of maximum density, from the viewpoint of control accuracy, it is necessary to form a test pattern with as high a density as possible within a range that can be detected by the optical sensor and detect the density. That is, as shown in FIG. 10, the change in the halftone density accompanying the change in the maximum density is larger in the high density portion (high gradation). It is desirable to set the gradation so that a change in density can be detected.

しかし、光学センサの検出可能な範囲は、センサ自体の個体差、取付け精度のばらつきなどによって異なり、また、トナー粉煙や紙粉による汚れなどで経時的にも変化する。そのため、極力高濃度でテストパターンを形成し、その濃度を検出しようとしても、画像形成装置間でのばらつきや経時的な変化で最大濃度の状態が正確に検出できないという課題が残っていた。つまり、図１１に示すように、最大濃度の変動に伴って領域Ｙでは最大濃度の変動が検出できない。   However, the detectable range of the optical sensor varies depending on individual differences in the sensor itself, variations in mounting accuracy, and the like, and also changes over time due to contamination with toner dust and paper dust. For this reason, even when a test pattern is formed with a high density as much as possible and the density is detected, there remains a problem that the state of the maximum density cannot be accurately detected due to variations among image forming apparatuses and changes with time. That is, as shown in FIG. 11, the maximum density variation cannot be detected in the region Y with the maximum density variation.

本発明の目的は、最大濃度状態検出制御で用いるテストパターンの最も好ましい階調を精度よく決定できる画像形成装置を提供することにある。   An object of the present invention is to provide an image forming apparatus capable of accurately determining the most preferable gradation of a test pattern used in maximum density state detection control.

本発明の一形態である画像形成装置は、
像担持体上にトナー像を形成する画像形成手段と、
前記像担持体上に形成されたトナー像の濃度を光学的に検出する検出手段と、
前記画像形成手段の動作を制御する制御手段と、
を備え、
前記制御手段は、前記像担持体上にトナーによる複数の濃度水準からなる制御パターンを形成し、前記検出手段による該制御パターンの濃度検出限界に応じて最大濃度の変動を推定し、前記テストパターンの階調を決定する状態検出制御を実行し、
前記制御手段は、前記決定された階調でテストパターンを前記像担持体上に形成し、前記検出手段による該テストパターンの濃度検出結果に応じて最大濃度状態検出制御を実行すること、
を特徴とする。 An image forming apparatus according to an aspect of the present invention is
Image forming means for forming a toner image on the image carrier;
Detection means for optically detecting the density of the toner image formed on the image carrier;
Control means for controlling the operation of the image forming means;
With
The control means forms a control pattern having a plurality of density levels by toner on the image carrier, estimates a variation in maximum density according to a density detection limit of the control pattern by the detection means, and Execute state detection control to determine the gradation of
The control unit forms a test pattern on the image carrier with the determined gradation, and executes maximum density state detection control according to a density detection result of the test pattern by the detection unit;
It is characterized by.

前記画像形成装置において、制御手段は像担持体上にトナーによる複数の濃度水準からなる制御パターンを形成し、光学的な検出手段による該制御パターンの濃度検出結果が最大濃度となった階調を最大濃度状態検出制御でのテストパターンの階調に決定する状態検出制御を実行する。これにて、画像安定化制御の前提となる最大濃度状態検出制御で用いるテストパターンの最も好ましい階調が、装置の個体差や経時変化に拘わらず精度よく決定される。   In the image forming apparatus, the control unit forms a control pattern having a plurality of density levels with toner on the image carrier, and the gradation at which the density detection result of the control pattern by the optical detection unit becomes the maximum density is obtained. State detection control for determining the gradation of the test pattern in the maximum density state detection control is executed. As a result, the most preferable gradation of the test pattern used in the maximum density state detection control, which is the premise of the image stabilization control, is accurately determined regardless of the individual difference of the apparatus and the change over time.

本発明によれば、最大濃度状態検出制御のために像担持体上に形成されるテストパターンの最も好ましい階調を精度よく決定できる。   According to the present invention, the most preferable gradation of the test pattern formed on the image carrier for maximum density state detection control can be accurately determined.

一実施例である画像形成装置の概略構成図である。1 is a schematic configuration diagram of an image forming apparatus according to an embodiment. 画像安定化制御を示すフローチャート図である。It is a flowchart figure which shows image stabilization control. ガンマ補正制御パターンを示す模式図である。It is a schematic diagram which shows a gamma correction control pattern. 状態検出制御を示すフローチャート図である。It is a flowchart figure which shows state detection control. ガンマ補正制御パターンの検出濃度を示すチャート図である。It is a chart figure which shows the detection density of a gamma correction control pattern. テストパターンの設定濃度を示すチャート図である。It is a chart figure which shows the setting density | concentration of a test pattern. 最大濃度状態検出制御を示すフローチャート図である。It is a flowchart figure which shows maximum density | concentration state detection control. 光学センサによるトナー付着量検出特性を示すグラフである。It is a graph which shows the toner adhesion amount detection characteristic by an optical sensor. 現像バイアス電圧に対するトナー付着量を示すグラフである。6 is a graph showing a toner adhesion amount with respect to a developing bias voltage. 最大濃度の変動に伴う中間調濃度の変動を示すグラフである。It is a graph which shows the fluctuation | variation of the halftone density accompanying the fluctuation | variation of the maximum density. 最大濃度の変動を検出できない領域を示すグラフである。It is a graph which shows the area | region which cannot detect the fluctuation | variation of the maximum density | concentration.

以下、本発明に係る画像形成装置の実施例について、添付図面を参照して説明する。なお、各図において同じ部材、部分には共通する符号を付し、重複する説明は省略する。   Embodiments of an image forming apparatus according to the present invention will be described below with reference to the accompanying drawings. In addition, the same code | symbol is attached | subjected to the same member and part in each figure, and the overlapping description is abbreviate | omitted.

一実施例である画像形成装置１は、図１に示すように、タンデム方式でカラー画像を形成するようにしたものである。即ち、四つのプロセスユニット１０（イエロー画像用のユニット１０ｙ、マゼンタ画像用のユニット１０ｍ、シアン画像用のユニット１０ｃ、ブラック画像用のユニット１０ｋ）が並置されており、各感光体１１上に形成された各色のトナー画像を矢印Ａ方向に回転駆動される中間転写ベルト３１上に各転写ローラ３２から付与される電界により転写／合成（１次転写）する。その後、合成トナー画像を転写ローラ３５から付与される電界により記録媒体（用紙）上に２次転写する。   An image forming apparatus 1 according to an embodiment forms a color image by a tandem method as shown in FIG. That is, four process units 10 (a unit for yellow image 10y, a unit for magenta image 10m, a unit for cyan image 10c, and a unit for black image 10k) are juxtaposed and formed on each photoconductor 11. The toner images of the respective colors are transferred / combined (primary transfer) onto the intermediate transfer belt 31 that is rotationally driven in the direction of arrow A by an electric field applied from each transfer roller 32. Thereafter, the composite toner image is secondarily transferred onto a recording medium (paper) by an electric field applied from the transfer roller 35.

それぞれの感光体１１の周囲には、帯電ローラ１２、現像器１３、残留トナーのクリーニングブレード１４などが配置されており、さらに感光体１１上に静電潜像を形成するレーザー走査光学ユニット２０が配置されている。この種のプロセスユニット１０によって電子写真方式で感光体１１上にトナー画像を形成し、該トナー画像を中間転写ベルト３１上に１次転写し、さらに記録媒体上に２次転写するプロセスは周知である。   Around each photoconductor 11, a charging roller 12, a developing device 13, a residual toner cleaning blade 14, and the like are arranged, and a laser scanning optical unit 20 that forms an electrostatic latent image on the photoconductor 11. Has been placed. A process in which a toner image is formed on the photoconductor 11 by an electrophotographic method using this type of process unit 10, the toner image is primarily transferred onto the intermediate transfer belt 31, and then secondarily transferred onto a recording medium is well known. is there.

記録媒体（用紙）は、給紙カセット５０に積載収容されており、給紙ローラ５１によって１枚ずつ給紙される。給紙された用紙は、レジストローラ対５２を介して２次転写部へ搬送され、前記中間転写ベルト３１からトナー画像が２次転写される。その後、用紙は定着ユニット５５でトナーの加熱定着を施され、排出ローラ対５６から排出部５７へ排出される。   The recording medium (paper) is stacked and accommodated in the paper feed cassette 50 and is fed one by one by the paper feed roller 51. The fed paper is conveyed to the secondary transfer section via the registration roller pair 52, and the toner image is secondarily transferred from the intermediate transfer belt 31. Thereafter, the toner is heated and fixed by the fixing unit 55, and is discharged from the discharge roller pair 56 to the discharge unit 57.

画像形成装置１においては、まず、帯電量、露光光量、現像バイアス電圧などの作像条件を所定の値として感光体１１上にトナーにてパターンを形成し、中間転写ベルト３１上に転写する。そして、中間転写ベルト３１上に転写されたトナーパターンの濃度をセンサＳＥ１にて光学的に検出し、この検出値に基づいて、以下に説明する画像安定化制御、状態検出制御、最大濃度状態検出制御を行う。これらの制御は画像形成装置１の全体的な制御とともに、制御部６０を構成するＣＰＵにて実行される。   In the image forming apparatus 1, first, a pattern is formed with a toner on the photosensitive member 11 with image forming conditions such as a charge amount, an exposure light amount, and a developing bias voltage as predetermined values, and transferred onto the intermediate transfer belt 31. Then, the density of the toner pattern transferred onto the intermediate transfer belt 31 is optically detected by the sensor SE1, and based on this detected value, image stabilization control, state detection control, and maximum density state detection described below are performed. Take control. These controls are executed by the CPU constituting the control unit 60 together with the overall control of the image forming apparatus 1.

画像安定化制御は、図２に示すように、光学センサＳＥ１の出力電圧が適正になるように校正し（ステップＳ１）、トナーの感光体１１への付着量（現像効率）が最大濃度となるように現像バイアス電圧を制御し（ステップＳ２）、光学ユニット２０のＬＤ光量（露光光量）を適正に制御し（ステップＳ３）、ガンマ補正制御を実行する（ステップＳ４）。   As shown in FIG. 2, the image stabilization control is calibrated so that the output voltage of the optical sensor SE1 is appropriate (step S1), and the toner adhesion amount (development efficiency) becomes the maximum density. Thus, the developing bias voltage is controlled (step S2), the LD light amount (exposure light amount) of the optical unit 20 is appropriately controlled (step S3), and gamma correction control is executed (step S4).

図３にガンマ補正制御に使用する制御パターン３６Ｙ（イエロー），３６Ｍ（マゼンタ），３６Ｃ（シアン），３６Ｋ（ブラック）を示す。この制御パターン３６Ｙ，３６Ｍ，３６Ｃ，３６Ｋは、図３では、それぞれの感光体１１上に形成されて中間転写ベルト３１上に転写された状態で示しており、低濃度から最大濃度までの複数の階調にて形成されている。ガンマ補正はこの制御パターンを使用して行われる周知の制御であり、この制御パターンを本実施例における状態検出制御でも利用する。   FIG. 3 shows control patterns 36Y (yellow), 36M (magenta), 36C (cyan), and 36K (black) used for gamma correction control. The control patterns 36Y, 36M, 36C, and 36K are shown in a state where they are formed on the respective photoreceptors 11 and transferred onto the intermediate transfer belt 31 in FIG. 3, and a plurality of control patterns 36 from low density to maximum density are shown. It is formed with gradation. The gamma correction is a well-known control performed using this control pattern, and this control pattern is also used in the state detection control in this embodiment.

図４に、ガンマ補正制御に使用する前記制御パターン３６Ｙ，３６Ｍ，３６Ｃ，３６Ｋを利用して光学センサＳＥ１の検出範囲を演算し、最大濃度状態検出制御で用いるテストパターンの階調を決定する手順を示す。具体的には、前記ガンマ補正用制御パターンを中間転写ベルト３１上に形成し（ステップＳ１１）、光学センサＳＥ１にてその濃度を検出し（ステップＳ１２）、その検出値を濃度に変換する（ステップＳ１３）。光学センサＳＥ１の検出値に対する濃度は予め測定されており、ＣＰＵ６０にルックアップテーブルなどで格納されている。   FIG. 4 shows a procedure for calculating the detection range of the optical sensor SE1 using the control patterns 36Y, 36M, 36C, and 36K used for gamma correction control and determining the gradation of the test pattern used in the maximum density state detection control. Indicates. Specifically, the control pattern for gamma correction is formed on the intermediate transfer belt 31 (step S11), the density is detected by the optical sensor SE1 (step S12), and the detected value is converted into the density (step S11). S13). The density with respect to the detection value of the optical sensor SE1 is measured in advance and is stored in the CPU 60 in a lookup table or the like.

次に、光学センサＳＥ１の検出範囲を算出し（ステップＳ１４）、テストパターンの階調を決定する（ステップＳ１５）。図５に示すように、光学センサＳＥ１の検出範囲以上の濃度では出力電圧が飽和し、検出値から変換する濃度も飽和する。即ち、光学センサＳＥ１での検出範囲以上の濃度は飽和してしまう。このように、飽和した検出濃度を光学センサＳＥ１の検出範囲として算出することができる。２５５階調の検出濃度を飽和濃度として扱ってもよい。最大濃度状態検出制御のテストパターンの階調（濃度）は検出飽和濃度で形成した場合、最大濃度が濃くなる方向に変化した場合、濃度変化を検出できないため、検出飽和濃度よりも低い濃度で形成する必要があり、最大濃度の変動許容幅から算出する。   Next, the detection range of the optical sensor SE1 is calculated (step S14), and the gradation of the test pattern is determined (step S15). As shown in FIG. 5, the output voltage is saturated at a concentration not lower than the detection range of the optical sensor SE1, and the concentration converted from the detected value is also saturated. That is, the density beyond the detection range of the optical sensor SE1 is saturated. Thus, the saturated detected density can be calculated as the detection range of the optical sensor SE1. The detected density of 255 gradations may be treated as a saturated density. The gradation (density) of the test pattern for maximum density state detection control is formed at a density lower than the detected saturation density because it cannot be detected when the maximum density changes in the direction of increasing the maximum density when it is formed at the detected saturation density. It is necessary to calculate the maximum density from the allowable fluctuation range.

具体的には、図６に示すように、最大濃度の変動許容幅をΔＭ％と設定し、光学センサＳＥ１の検出上限濃度をＬ、状態検出制御パターンの濃度をＴとした場合、Ｔ＝Ｌ／（１＋Ｍ／１００）で算出する。最大濃度の変動幅と同じ割合で高濃度部も変動すると仮定している。   Specifically, as shown in FIG. 6, when the allowable variation range of the maximum density is set to ΔM%, the detection upper limit density of the optical sensor SE1 is L, and the density of the state detection control pattern is T, T = L / (1 + M / 100). It is assumed that the high density portion also fluctuates at the same rate as the fluctuation range of the maximum density.

最大濃度の状態検出制御は、連続印字動作中であって用紙が作像部に送り込まれていないとき、装置１の電源をオンしたときの初期動作終了後、印字動作の直前などのタイミングで実行する。図７に示すように、前記ステップＳ１５で決定された階調でテストパターンを中間転写ベルト３１上に形成し（ステップＳ２１）、光学センサＳＥ１にてその濃度を検出し（ステップＳ２２）、その検出値を濃度に変換する（ステップＳ２３）。濃度検出結果が変動許容幅以内であれば（ステップＳ２４でＹＥＳ）、作像条件を微調整する（ステップＳ２５）。作像条件とは、現像バイアス電圧、ＬＤ光量（露光光量）などである。一方、濃度検出結果が許容幅を超えて変動していれば（ステップＳ２４でＮＯ）、印字動作を中断し、画像安定化制御を起動して最大濃度制御を実行する（ステップＳ２６）。   The maximum density state detection control is executed at a timing such as immediately before the printing operation after the initial operation when the apparatus 1 is turned on when the paper is not sent to the image forming unit during continuous printing operation. To do. As shown in FIG. 7, a test pattern is formed on the intermediate transfer belt 31 with the gradation determined in step S15 (step S21), and its density is detected by the optical sensor SE1 (step S22). The value is converted into a density (step S23). If the density detection result is within the allowable fluctuation range (YES in step S24), the image forming conditions are finely adjusted (step S25). The image forming conditions include a developing bias voltage, an LD light amount (exposure light amount), and the like. On the other hand, if the density detection result fluctuates beyond the allowable range (NO in step S24), the printing operation is interrupted, the image stabilization control is activated, and the maximum density control is executed (step S26).

濃度が濃い方向に変動していた場合は、最大濃度制御のテストパターンを薄い濃度に設定し、濃度が薄い方向に変動していた場合は、最大濃度制御のテストパターンを濃い濃度に設定する。   If the density varies in the dark direction, the maximum density control test pattern is set to a light density, and if the density varies in the light direction, the maximum density control test pattern is set to a dark density.

以上の制御にて、最大濃度状態検出制御で用いるテストパターンの最も好ましい階調が、装置の個体差や経時変化に拘わらず精度よく決定される。   By the above control, the most preferable gradation of the test pattern used in the maximum density state detection control is determined with high accuracy regardless of individual differences of devices and changes with time.

なお、本発明に係る、画像形成装置は前記実施例に限定するものではなく、その要旨の範囲内で種々に変更することができる。   The image forming apparatus according to the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the gist thereof.

前記実施例では、ガンマ補正制御を利用して光学センサの検出範囲を算出する例を示したが、ＬＤ光量、現像バイアス電圧を変化させることで制御パターンの濃度を変化させ、光学センサの検出範囲を算出してもよい。また、状態検出制御パターンの濃度Ｔは予めルックアップテーブルとして設定しておいてもよい。   In the above embodiment, the gamma correction control is used to calculate the detection range of the optical sensor. However, the density of the control pattern is changed by changing the LD light amount and the development bias voltage, and the detection range of the optical sensor is changed. May be calculated. Further, the density T of the state detection control pattern may be set in advance as a lookup table.

また、画像形成装置としては、その基本的な構成や細部の構成は任意であり、プリント機能のみを備えたもの以外に、通信機能やファクシミリ機能などを備えた複合機であってもよい。   In addition, the basic configuration and detailed configuration of the image forming apparatus are arbitrary, and may be a multifunction machine having a communication function, a facsimile function, and the like in addition to a printer having only a print function.

以上のように、本発明は、画像形成装置に有用であり、特に、最大濃度状態検出制御に用いるテストパターンの最も好ましい階調を精度よく決定できる点で優れている。   As described above, the present invention is useful for an image forming apparatus, and is particularly excellent in that the most preferable gradation of a test pattern used for maximum density state detection control can be accurately determined.

１０…プロセスユニット
１１…感光体
１３…現像器
３１…中間転写ベルト
３６…制御用パターン
６０…制御部
ＳＥ１…濃度検出用光学センサ DESCRIPTION OF SYMBOLS 10 ... Process unit 11 ... Photoconductor 13 ... Developing device 31 ... Intermediate transfer belt 36 ... Control pattern 60 ... Control part SE1 ... Optical sensor for density detection

Claims (8)

像担持体上にトナー像を形成する画像形成手段と、
前記像担持体上に形成されたトナー像の濃度を光学的に検出する検出手段と、
前記画像形成手段の動作を制御する制御手段と、
を備え、
前記制御手段は、前記像担持体上にトナーによる複数の濃度水準からなる制御パターンを形成し、前記検出手段による該制御パターンの濃度検出限界に応じて最大濃度の変動を推定し、テストパターンの階調を決定する状態検出制御を実行し、
前記制御手段は、前記決定された階調でテストパターンを前記像担持体上に形成し、前記検出手段による該テストパターンの濃度検出結果に応じて最大濃度状態検出制御を実行すること、
を特徴とする画像形成装置。 Image forming means for forming a toner image on the image carrier;
Detection means for optically detecting the density of the toner image formed on the image carrier;
Control means for controlling the operation of the image forming means;
With
The control means forms a control pattern consisting of a plurality of density levels by toner on the image carrier, estimates a variation in maximum density according to the density detection limit of the control pattern by the detection means, and Execute state detection control to determine gradation,
The control unit forms a test pattern on the image carrier with the determined gradation, and executes maximum density state detection control according to a density detection result of the test pattern by the detection unit;
An image forming apparatus. 前記制御手段は、前記状態検出制御において、露光光量、現像バイアス電圧、濃度階調のいずれかを変化させて複数の濃度水準からなる制御パターンを形成し、前記検出手段による該制御パターンの濃度検出結果から該検出手段の濃度検出限界を演算すること、を特徴とする請求項１に記載の画像形成装置。   In the state detection control, the control unit forms a control pattern having a plurality of density levels by changing any one of the exposure light amount, the developing bias voltage, and the density gradation, and detects the density of the control pattern by the detection unit. The image forming apparatus according to claim 1, wherein a density detection limit of the detection unit is calculated from a result. 前記制御手段は、前記テストパターンの階調を前記検出手段の濃度検出限界よりも低い濃度となる階調とすること、を特徴とする請求項１又は請求項２に記載の画像形成装置。   The image forming apparatus according to claim 1, wherein the control unit sets the gradation of the test pattern to a gradation that has a density lower than a density detection limit of the detection unit. 前記制御手段は、前記テストパターンの階調を最大濃度の変動許容幅と前記検出手段の濃度検出限界とから決定すること、を特徴とする請求項１ないし請求項３のいずれかに記載の画像形成装置。   The image according to any one of claims 1 to 3, wherein the control means determines the gradation of the test pattern from a maximum density fluctuation allowable range and a density detection limit of the detection means. Forming equipment. 前記制御手段は、前記最大濃度状態検出制御を、画像形成装置が所定時間駆動されないとき、所定枚数の印字が実行されたとき、温度湿度が所定範囲外に変化したとき、連続印字動作中であって用紙が作像部に送り込まれていないとき、のいずれかに実行すること、を特徴とする請求項１ないし請求項４のいずれかに記載の画像形成装置。   The control means performs the maximum density state detection control during a continuous printing operation when the image forming apparatus is not driven for a predetermined time, when a predetermined number of printings are performed, or when the temperature and humidity change outside a predetermined range. The image forming apparatus according to claim 1, wherein the image forming apparatus is executed when the sheet is not sent to the image forming unit. 前記制御手段は、前記検出手段による前記テストパターンの濃度検出結果が所定範囲内である場合、現像バイアス電圧又は露光光量のいずれかを変化させること、を特徴とする請求項１ないし請求項５のいずれかに記載の画像形成装置。   6. The control unit according to claim 1, wherein when the density detection result of the test pattern by the detection unit is within a predetermined range, either the development bias voltage or the exposure light amount is changed. The image forming apparatus according to any one of the above. 前記制御手段は、前記検出手段による前記テストパターンの濃度検出結果が所定範囲外である場合、印字動作を中断して画像安定化制御を実行すること、を特徴とする請求項１ないし請求項６のいずれかに記載の画像形成装置。   7. The control unit according to claim 1, wherein when the density detection result of the test pattern by the detection unit is outside a predetermined range, the printing operation is interrupted and image stabilization control is executed. The image forming apparatus according to any one of the above. 画像形成装置の製造工程において、前記状態検出制御が実行され、前記テストパターンの階調が決定されていること、を特徴とする請求項１ないし請求項４のいずれかに記載の画像形成装置。   The image forming apparatus according to claim 1, wherein the state detection control is executed and a gradation of the test pattern is determined in a manufacturing process of the image forming apparatus.
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Citations (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH05323706A (en) * 1992-05-22 1993-12-07 Mita Ind Co Ltd Image forming device
JPH0954470A (en) * 1995-08-18 1997-02-25 Ricoh Co Ltd Potential control method and developing ability control method for image forming device
JPH09222780A (en) * 1996-02-16 1997-08-26 Konica Corp Image forming device
JP2003035978A (en) * 2001-07-23 2003-02-07 Canon Inc Image forming apparatus
US20040156047A1 (en) * 2003-02-12 2004-08-12 Canon Kabushiki Kasiha Color image forming apparatus and color measurement controlling method therefor
JP2005091767A (en) * 2003-09-17 2005-04-07 Fuji Xerox Co Ltd Image forming apparatus
JP2005274771A (en) * 2004-03-23 2005-10-06 Canon Inc Image forming apparatus and image forming method
JP2006106222A (en) * 2004-10-01 2006-04-20 Konica Minolta Business Technologies Inc Image forming apparatus and its developing bias value setting method
JP2006259077A (en) * 2005-03-16 2006-09-28 Canon Inc Image forming apparatus
JP2008252660A (en) * 2007-03-30 2008-10-16 Kyocera Mita Corp Image forming apparatus
JP2009145488A (en) * 2007-12-12 2009-07-02 Ricoh Co Ltd Developer carrier refreshing method, image forming apparatus, image forming method, process cartridge, and developing device
JP2009217163A (en) * 2008-03-12 2009-09-24 Oki Data Corp Image forming apparatus and image forming method
US20120002991A1 (en) * 2010-07-02 2012-01-05 Toshiba Tec Kabushiki Kaisha Image forming apparatus and image quality control method
JP2013101194A (en) * 2011-11-08 2013-05-23 Sharp Corp Image forming apparatus, system, printer driver, and method
JP2015004893A (en) * 2013-06-21 2015-01-08 キヤノン株式会社 Image formation device
JP2016177241A (en) * 2015-03-23 2016-10-06 カシオ計算機株式会社 Image formation device, toner adhesion control method and program

Patent Citations (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH05323706A (en) * 1992-05-22 1993-12-07 Mita Ind Co Ltd Image forming device
JPH0954470A (en) * 1995-08-18 1997-02-25 Ricoh Co Ltd Potential control method and developing ability control method for image forming device
JPH09222780A (en) * 1996-02-16 1997-08-26 Konica Corp Image forming device
JP2003035978A (en) * 2001-07-23 2003-02-07 Canon Inc Image forming apparatus
US20040156047A1 (en) * 2003-02-12 2004-08-12 Canon Kabushiki Kasiha Color image forming apparatus and color measurement controlling method therefor
JP2004245931A (en) * 2003-02-12 2004-09-02 Canon Inc Color image forming apparatus, color measurement control method for the apparatus, and computer readable storage medium and program
JP2005091767A (en) * 2003-09-17 2005-04-07 Fuji Xerox Co Ltd Image forming apparatus
JP2005274771A (en) * 2004-03-23 2005-10-06 Canon Inc Image forming apparatus and image forming method
JP2006106222A (en) * 2004-10-01 2006-04-20 Konica Minolta Business Technologies Inc Image forming apparatus and its developing bias value setting method
JP2006259077A (en) * 2005-03-16 2006-09-28 Canon Inc Image forming apparatus
JP2008252660A (en) * 2007-03-30 2008-10-16 Kyocera Mita Corp Image forming apparatus
JP2009145488A (en) * 2007-12-12 2009-07-02 Ricoh Co Ltd Developer carrier refreshing method, image forming apparatus, image forming method, process cartridge, and developing device
JP2009217163A (en) * 2008-03-12 2009-09-24 Oki Data Corp Image forming apparatus and image forming method
US20120002991A1 (en) * 2010-07-02 2012-01-05 Toshiba Tec Kabushiki Kaisha Image forming apparatus and image quality control method
JP2013101194A (en) * 2011-11-08 2013-05-23 Sharp Corp Image forming apparatus, system, printer driver, and method
JP2015004893A (en) * 2013-06-21 2015-01-08 キヤノン株式会社 Image formation device
JP2016177241A (en) * 2015-03-23 2016-10-06 カシオ計算機株式会社 Image formation device, toner adhesion control method and program

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