JP2009282496A - Image forming apparatus - Google Patents

Image forming apparatus Download PDF

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JP2009282496A
JP2009282496A JP2009032227A JP2009032227A JP2009282496A JP 2009282496 A JP2009282496 A JP 2009282496A JP 2009032227 A JP2009032227 A JP 2009032227A JP 2009032227 A JP2009032227 A JP 2009032227A JP 2009282496 A JP2009282496 A JP 2009282496A
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transfer
image
downstream
rotational movement
toner
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Yoji Ueda
洋司 植田
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Kyocera Mita Corp
京セラミタ株式会社
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<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which is capable of performing stable image forming processing, without affecting the number of prints per unit time and toner consumption. <P>SOLUTION: A control circuit 30 temporarily transfers the patterns for adjusting image density of each color of developing devices 9 except the most downstream one in the rotational direction of an intermediate transfer belt 8 to the intermediate transfer belt 8, then, transfers the patterns to a photoreceptor 18(K) by applying a bias having a polarity opposite to that of a normal transfer bias to a transfer device 19(K), and then, measures the pattern density of the photoreceptor 18(K) by an optical sensor 33, to adjust the image density, in such a state that the pattern for adjusting the image density of color by the most downstream developing device 9(K) is held on the most downstream photoreceptor 18(K), without transferring the pattern onto the intermediate transfer belt 8, by applying the bias having a polarity opposite to that of the normal transfer bias to the most downstream transfer device 19(K). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

本発明は、転写紙搬送方向に順じてタンデム方式で配置された複数色対応の各現像装置により各像担持体に形成されたトナー像を順次転写すると共に、そのトナー像の画像信号を光学式センサで検知して画像濃度調整や色ずれ補正を行う画像形成装置に関する。   The present invention sequentially transfers a toner image formed on each image carrier by each developing device corresponding to a plurality of colors arranged in a tandem manner in the transfer paper conveyance direction, and optically transmits an image signal of the toner image. The present invention relates to an image forming apparatus that performs image density adjustment and color misregistration correction by detecting with a sensor.
従来から、検出用パターンを印字し、その検出用パターンの検出結果に基づいて印字画像のトナー付着量を制御したり、感光体や中間転写体等の駆動速度の補正量を設定して色ずれ補正を行う技術が知られている(例えば、特許文献1参照)。   Conventionally, color detection is performed by printing a detection pattern and controlling the toner adhesion amount of the printed image based on the detection result of the detection pattern, or setting a correction amount for the driving speed of the photosensitive member or intermediate transfer member. A technique for performing correction is known (see, for example, Patent Document 1).
特開平08−190244号公報Japanese Patent Laid-Open No. 08-190244
ところが、上記の如く構成された画像形成装置にあっては、このような制御をする時は画像濃度調整用又は画像色ずれ補正用の検出用パターンを用いているため、単位時間あたりの印字枚数の低下やトナー消費量の増大といった問題が生じていた。   However, since the image forming apparatus configured as described above uses a detection pattern for image density adjustment or image color misregistration correction when performing such control, the number of printed sheets per unit time is used. There have been problems such as a decrease in toner and an increase in toner consumption.
また、例えば、中間転写体を配置した画像形成装置の場合には、二次転写ローラを中間転写体に接離させる機構を設けなければ未転写トナー像が直接二次転写ローラに接触して二次転写ローラが汚れてしまう裏汚れの原因となっていた。   Further, for example, in the case of an image forming apparatus in which an intermediate transfer member is arranged, an untransferred toner image directly contacts the secondary transfer roller without being provided with a mechanism for bringing the secondary transfer roller into contact with or separated from the intermediate transfer member. This was the cause of back dirt that would cause the next transfer roller to become dirty.
さらに、未転写トナーはクリーニング装置で回収する必要があるため、クリーニング装置への負担も大きく、一回(一回転・一サイクル)のクリーニング動作によって未転写トナーを回収することができない場合には複数回のクリーニング動作を実行する必要があり、単位時間当たりの印字枚数も低下してしまう。   Furthermore, since the untransferred toner needs to be collected by the cleaning device, the burden on the cleaning device is heavy, and there are a plurality of cases where the untransferred toner cannot be collected by one cleaning operation (one rotation / one cycle). It is necessary to execute cleaning operations one time, and the number of printed sheets per unit time is also reduced.
しかも、中間転写体上で検出用パターンを検出する場合には、中間転写体の表面状態が使用頻度(耐久性)や固体ばらつき等によって変化する為、画像形成装置毎でそれらの影響を補正する必要があり、トナー量を高精度に測定することは困難であった。   In addition, when detecting the detection pattern on the intermediate transfer member, the surface state of the intermediate transfer member changes depending on the frequency of use (durability), variation in solids, etc., and therefore the influence of each image forming apparatus is corrected. Therefore, it is difficult to measure the toner amount with high accuracy.
また、中間転写体がベルト状である場合、ベルトのバタツキにより、検出用パターンの位置や濃度を検出するためのセンサまでの距離が変わってしまうという問題もあった。   Further, when the intermediate transfer member has a belt shape, there is a problem that the distance to the sensor for detecting the position and density of the detection pattern changes due to the flutter of the belt.
そこで、本発明は、上記事情を考慮し、単位時間あたりの印字枚数やトナー消費量に影響を与えることなく、安定した画像形成処理を行うことができる画像形成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 an image forming apparatus capable of performing stable image forming processing without affecting the number of printed sheets per unit time and toner consumption. .
本発明の画像形成装置は、転写材搬送方向に順じて回動移動可能な中間転写体と、該中間転写体の回動移動方向に沿ってタンデム方式で配置された複数色対応の各現像装置により各像担持体に形成されたトナー像を前記中間転写体上に転写する転写デバイスと、前記中間転写体の回動移動方向最下流に配置された前記像担持体に形成されたトナー像の画像濃度信号を出力する光学式センサと、該光学式センサから出力された画像濃度信号に基づいて前記現像装置の画像濃度調整を行う制御回路と、を備えた画像形成装置において、前記制御回路は、前記中間転写体の回動移動方向最下流以外に配置された前記現像装置による各色の画像濃度調整用パターンにあっては一旦前記中間転写体上に転写したうえでその画像濃度調整用パターンを前記中間転写体の回動移動方向最下流に配置された前記転写デバイスに通常の転写バイアスとは逆極性のバイアスを印加することによって前記中間転写体の回動移動方向最下流に配置された前記像担持体に転写させた後に、また、前記中間転写体の回動移動方向最下流に配置された前記現像装置による色の画像濃度調整用パターンにあっては前記中間転写体の回動移動方向最下流に配置された前記転写デバイスに通常の転写バイアスとは逆極性のバイアスを印加することによって前記中間転写体上に転写することなく画像濃度調整用パターンを前記中間転写体の回動移動方向最下流に配置された前記像担持体に保持した状態で、それぞれ、前記中間転写体の回動移動方向最下流に配置された前記像担持体上の画像濃度調整用パターン濃度を前記光学式センサで測定して画像濃度調整を行うことを特徴とする。   The image forming apparatus according to the present invention includes an intermediate transfer body that can be rotated in the transfer material conveyance direction, and each development corresponding to a plurality of colors arranged in a tandem manner along the rotation movement direction of the intermediate transfer body. A transfer device for transferring a toner image formed on each image carrier by the apparatus onto the intermediate transfer member, and a toner image formed on the image carrier disposed on the most downstream side in the rotational movement direction of the intermediate transfer member. In the image forming apparatus, comprising: an optical sensor that outputs an image density signal of the image; and a control circuit that adjusts the image density of the developing device based on the image density signal output from the optical sensor. Is a pattern for adjusting the image density of each color by the developing device arranged at a position other than the most downstream in the rotational movement direction of the intermediate transfer member, and is transferred to the intermediate transfer member and then the image density adjustment pattern. The above The image arranged at the most downstream side in the rotational movement direction of the intermediate transfer body by applying a bias having a polarity opposite to a normal transfer bias to the transfer device arranged at the most downstream side in the rotational movement direction of the intermediate transfer body. In the pattern for adjusting the image density of the color by the developing device disposed downstream of the intermediate transfer member in the rotational movement direction after being transferred to the carrier, the intermediate transfer member is moved to the maximum in the rotational movement direction. By applying a bias having a polarity opposite to that of a normal transfer bias to the transfer device disposed downstream, the image density adjustment pattern is transferred to the maximum in the rotational movement direction of the intermediate transfer member without being transferred onto the intermediate transfer member. The image density adjusting pattern density on the image carrier disposed on the most downstream side in the rotational movement direction of the intermediate transfer member is held in the image carrier disposed downstream. And performs image density adjustment as determined by the formula sensor.
本発明の画像形成装置は、転写材搬送方向に順じて回動移動可能な中間転写体と、該中間転写体の回動移動方向に沿ってタンデム方式で配置された複数色対応の各現像装置により各像担持体に形成されたトナー像を中間転写体上に転写する転写デバイスと、前記中間転写体の回動移動方向最下流に配置された前記像担持体に形成されたトナー像の画像位置信号を出力する光学式センサと、該光学式センサから出力された画像位置信号に基づいて色ずれ補正を行う制御回路と、を備えた画像形成装置において、前記制御回路は、前記中間転写体の回動移動方向最下流以外に配置された前記現像装置による各色の色ずれ補正用パターンにあっては一旦前記中間転写体上に転写したうえでその色ずれ補正用パターンを前記中間転写体の回動移動方向最下流に配置された前記転写デバイスに通常の転写バイアスとは逆極性のバイアスを印加することによって前記中間転写体の回動移動方向最下流に配置された前記像担持体に転写させた後に、また、前記中間転写体の回動移動方向最下流に配置された前記現像装置による色の色ずれ補正用パターンにあっては前記中間転写体の回動移動方向最下流に配置された前記転写デバイスに通常の転写バイアスとは逆極性のバイアスを印加することによって前記中間転写体上に転写することなく色ずれ補正用パターンを前記中間転写体の回動移動方向最下流に配置された前記像担持体に保持した状態で、それぞれ、前記中間転写体の回動移動方向最下流に配置された前記像担持体上の色ずれ補正用パターン位置を前記光学式センサで測定して色ずれ補正を行うことを特徴とする。   The image forming apparatus according to the present invention includes an intermediate transfer body that can be rotated in the transfer material conveyance direction, and each development corresponding to a plurality of colors arranged in a tandem manner along the rotation movement direction of the intermediate transfer body. A transfer device for transferring a toner image formed on each image carrier by the apparatus onto the intermediate transfer member, and a toner image formed on the image carrier disposed on the most downstream side in the rotational movement direction of the intermediate transfer member. An image forming apparatus comprising: an optical sensor that outputs an image position signal; and a control circuit that performs color misregistration correction based on the image position signal output from the optical sensor. In the color misregistration correction pattern for each color by the developing device arranged at a position other than the most downstream in the rotational movement direction of the body, the color misregistration correction pattern is temporarily transferred onto the intermediate transfer body and then the color misregistration correction pattern is transferred to the intermediate transfer body. Rotation direction of After transferring the image to the image carrier disposed downstream in the rotational movement direction of the intermediate transfer member by applying a bias having a polarity opposite to a normal transfer bias to the transfer device disposed downstream, and In the color misregistration correction pattern by the developing device arranged on the most downstream side in the rotational movement direction of the intermediate transfer member, the transfer device arranged on the most downstream side in the rotational movement direction of the intermediate transfer member. The image carrier in which a color misregistration correction pattern is arranged on the most downstream side in the rotational movement direction of the intermediate transfer member without applying a bias having a polarity opposite to that of a normal transfer bias without being transferred onto the intermediate transfer member. In this state, the color misregistration correction pattern position on the image carrier disposed on the most downstream side in the rotational movement direction of the intermediate transfer member is measured by the optical sensor, thereby correcting the color misregistration. And performing.
本発明の画像形成装置は、転写材搬送方向に順じて回動移動可能な中間転写体と、該中間転写体の回動移動方向に沿ってタンデム方式で配置された複数色対応の各現像装置により各像担持体に形成されたトナー像を中間転写体上に転写する転写デバイスと、前記中間転写体の回動移動方向最下流に配置された前記像担持体に形成されたトナー像の画像位置信号を出力する光学式センサと、該光学式センサから出力された画像位置信号に基づいて色ずれ補正を行う制御回路と、を備えた画像形成装置において、前記制御回路は、所定のタイミングで前記各現像装置からトナーを吐き出すトナー吐き出しモードを起動させると共に、前記中間転写体の回動移動方向最下流以外に配置された前記現像装置からの吐出トナーにあっては一旦前記中間転写体上に転写したうえでその吐出トナーを前記中間転写体の回動移動方向最下流に配置された前記転写デバイスに通常の転写バイアスとは逆極性のバイアスを印加することによって前記中間転写体の回動移動方向最下流に配置された前記像担持体に転写させた後に、また、前記中間転写体の回動移動方向最下流に配置された前記現像装置からの吐出トナーにあっては前記中間転写体の回動移動方向最下流に配置された前記転写デバイスに通常の転写バイアスとは逆極性のバイアスを印加することによって前記中間転写体上に転写することなく吐出トナーを前記中間転写体の回動移動方向最下流に配置された前記像担持体に保持した状態で、それぞれ、前記中間転写体の回動移動方向最下流に配置された前記像担持体上の吐出トナー位置を前記光学式センサで測定して色ずれ補正を行うことを特徴とする。   The image forming apparatus according to the present invention includes an intermediate transfer body that can be rotated in the transfer material conveyance direction, and each development corresponding to a plurality of colors arranged in a tandem manner along the rotation movement direction of the intermediate transfer body. A transfer device for transferring a toner image formed on each image carrier by the apparatus onto the intermediate transfer member, and a toner image formed on the image carrier disposed on the most downstream side in the rotational movement direction of the intermediate transfer member. An image forming apparatus comprising: an optical sensor that outputs an image position signal; and a control circuit that performs color misregistration correction based on the image position signal output from the optical sensor. Then, a toner discharge mode for discharging toner from each of the developing devices is activated, and toner discharged from the developing device arranged at a position other than the most downstream in the rotational movement direction of the intermediate transfer member is temporarily used for the intermediate transfer. After transferring the toner onto the body, the discharge toner is applied to the transfer device arranged at the most downstream in the rotational movement direction of the intermediate transfer body by applying a bias having a polarity opposite to that of a normal transfer bias. After the toner image is transferred to the image carrier disposed on the most downstream side in the rotational movement direction, and the toner discharged from the developing device disposed on the most downstream side in the rotational movement direction of the intermediate transfer body is the intermediate. By applying a bias having a polarity opposite to that of a normal transfer bias to the transfer device arranged on the most downstream side in the rotational movement direction of the transfer body, the discharged toner is transferred onto the intermediate transfer body without being transferred onto the intermediate transfer body. While being held by the image carrier arranged at the most downstream side in the rotational movement direction, the discharge toner position on the image carrier arranged at the most downstream side in the rotational movement direction of the intermediate transfer member And performing color misregistration correction, as measured by Manabu sensor.
本発明の画像形成装置は、転写材搬送方向に順じて回動移動可能な中間転写体と、該中間転写体の回動移動方向に沿ってタンデム方式で配置された複数色対応の各現像装置により各像担持体に形成されたトナー像を中間転写体上に転写する転写デバイスと、前記中間転写体の回動移動方向最下流に配置された前記像担持体に形成されたトナー像の画像濃度信号を出力する光学式センサと、該光学式センサから出力された画像濃度信号に基づいて前記現像装置の画像濃度調整を行う制御回路と、を備えた画像形成装置において、前記制御回路は、所定のタイミングで前記現像装置からトナーを吐き出すトナー吐き出しモードを起動させると共に、前記中間転写体の回動移動方向最下流以外に配置された前記現像装置からの吐出トナーにあっては一旦前記中間転写体上に転写したうえでその吐出トナーを前記中間転写体の回動移動方向最下流に配置された前記転写デバイスに通常の転写バイアスとは逆極性のバイアスを印加することによって前記中間転写体の回動移動方向最下流に配置された前記像担持体に転写させた後に、また、前記中間転写体の回動移動方向最下流に配置された前記現像装置からの吐出トナーにあっては前記中間転写体の回動移動方向最下流に配置された前記転写デバイスに通常の転写バイアスとは逆極性のバイアスを印加することによって前記中間転写体上に転写することなく吐出トナーを前記中間転写体の回動移動方向最下流に配置された前記像担持体に保持した状態で、それぞれ、前記中間転写体の回動移動方向最下流に配置された前記像担持体上の吐出トナー濃度を前記光学式センサで測定して画像濃度調整を行うことを特徴とする。   The image forming apparatus according to the present invention includes an intermediate transfer body that can be rotated in the transfer material conveyance direction, and each development corresponding to a plurality of colors arranged in a tandem manner along the rotation movement direction of the intermediate transfer body. A transfer device for transferring a toner image formed on each image carrier by the apparatus onto the intermediate transfer member, and a toner image formed on the image carrier disposed on the most downstream side in the rotational movement direction of the intermediate transfer member. An image forming apparatus comprising: an optical sensor that outputs an image density signal; and a control circuit that adjusts the image density of the developing device based on the image density signal output from the optical sensor. The toner discharge mode for discharging the toner from the developing device at a predetermined timing is activated, and the toner discharged from the developing device arranged at a position other than the most downstream in the rotational movement direction of the intermediate transfer member is First, the toner is transferred onto the intermediate transfer member, and the discharged toner is applied to the transfer device disposed on the most downstream side in the rotational movement direction of the intermediate transfer member by applying a bias having a polarity opposite to that of a normal transfer bias. After the toner image is transferred to the image carrier disposed at the most downstream side in the rotational movement direction of the intermediate transfer member, the toner is discharged from the developing device disposed at the most downstream side in the rotational movement direction of the intermediate transfer member. In other words, by applying a bias having a polarity opposite to a normal transfer bias to the transfer device arranged on the most downstream side in the rotational movement direction of the intermediate transfer member, the discharged toner is transferred without being transferred onto the intermediate transfer member. While being held by the image carrier disposed at the most downstream side in the rotational movement direction of the intermediate transfer member, the discharge tray on the image carrier disposed at the most downstream side in the rotational movement direction of the intermediate transfer member, respectively. And performs image density adjustment by measuring the over concentration by the optical sensor.
この際、前記光学式センサよりも前記中間転写体の回動移動方向下流側で前記像担持体上のトナー濃度を測定する第2光学式センサを備え、前記制御回路は、前記最下流に配置された像担持体上の画像濃度調整用パターンの濃度を前記光学式センサで測定すると共に、前記中間転写体上に残った又は転写されてしまったトナーの濃度を前記第2光学式センサで測定し、これら各センサからの測定結果に基づいて画像濃度調整を行うことも可能である。   In this case, a second optical sensor that measures the toner density on the image carrier on the downstream side in the rotational movement direction of the intermediate transfer member with respect to the optical sensor is provided, and the control circuit is disposed on the most downstream side. The density of the image density adjustment pattern on the image carrier thus measured is measured by the optical sensor, and the density of the toner remaining on or transferred to the intermediate transfer body is measured by the second optical sensor. It is also possible to perform image density adjustment based on the measurement results from these sensors.
また、前記光学式センサの感度よりも前記第2光学式センサの感度の方が高いのが好ましい。   Moreover, it is preferable that the sensitivity of the second optical sensor is higher than the sensitivity of the optical sensor.
本発明の画像形成装置は、転写材搬送方向に順じて回動移動可能な転写体と、該転写体の回動移動方向に沿ってタンデム方式で配置された複数色対応の各現像装置により各像担持体に形成されたトナー像を転写体により搬送される転写材上に転写する転写デバイスと、前記転写体の回動移動方向最下流に配置された前記像担持体に形成されたトナー像の画像濃度信号を出力する光学式センサと、該光学式センサから出力された画像濃度信号に基づいて前記現像装置の画像濃度調整を行う制御回路と、を備えた画像形成装置において、前記制御回路は、前記転写体の回動移動方向最下流以外に配置された前記現像装置による各色の画像濃度調整用パターンにあっては一旦前記転写体上に転写したうえでその画像濃度調整用パターンを前記転写体の回動移動方向最下流に配置された前記転写デバイスに通常の転写バイアスとは逆極性のバイアスを印加することによって前記転写体の回動移動方向最下流に配置された前記像担持体に転写させた後に、また、前記転写体の回動移動方向最下流に配置された前記現像装置による色の画像濃度調整用パターンにあっては前記転写体の回動移動方向最下流に配置された前記転写デバイスに通常の転写バイアスとは逆極性のバイアスを印加することによって前記転写体上に転写することなく画像濃度調整用パターンを前記転写体の回動移動方向最下流に配置された前記像担持体に保持した状態で、それぞれ、前記転写体の回動移動方向最下流に配置された前記像担持体上の画像濃度調整用パターン濃度を前記光学式センサで測定して画像濃度調整を行うことを特徴とする。   The image forming apparatus according to the present invention includes a transfer body that can be rotated in the transfer material conveyance direction, and developing devices that support a plurality of colors arranged in a tandem manner along the rotation movement direction of the transfer body. A transfer device for transferring a toner image formed on each image carrier onto a transfer material conveyed by the transfer member, and a toner formed on the image carrier disposed on the most downstream side in the rotational movement direction of the transfer member An image forming apparatus comprising: an optical sensor that outputs an image density signal of an image; and a control circuit that adjusts the image density of the developing device based on the image density signal output from the optical sensor. The circuit temporarily transfers the image density adjustment pattern for each color by the developing device arranged at a position other than the most downstream in the rotational movement direction of the transfer body onto the transfer body, and then transfers the image density adjustment pattern to the transfer body. The transfer body By applying a bias having a polarity opposite to that of a normal transfer bias to the transfer device arranged on the most downstream side in the rotational movement direction, the transfer device is transferred to the image carrier arranged on the most downstream side in the rotational movement direction of the transfer body. After that, in the color image density adjustment pattern by the developing device arranged at the most downstream side in the rotational movement direction of the transfer body, the transfer arranged at the most downstream side in the rotational movement direction of the transfer body. The image carrier in which an image density adjustment pattern is arranged on the most downstream side in the rotational movement direction of the transfer body without transferring the image onto the transfer body by applying a bias having a polarity opposite to a normal transfer bias to the device. In this state, the image density adjustment pattern density on the image carrier disposed on the most downstream side in the rotational movement direction of the transfer body is measured by the optical sensor to adjust the image density. And wherein the Ukoto.
本発明の画像形成装置は、転写材搬送方向に順じて回動移動可能な転写体と、該転写体の回動移動方向に沿ってタンデム方式で配置された複数色対応の各現像装置により各像担持体に形成されたトナー像を転写体により搬送される転写材上に転写する転写デバイスと、前記転写体の回動移動方向最下流に配置された前記像担持体に形成されたトナー像の画像位置信号を出力する光学式センサと、該光学式センサから出力された画像位置信号に基づいて色ずれ補正を行う制御回路と、を備えた画像形成装置において、前記制御回路は、前記転写体の回動移動方向最下流以外に配置された前記現像装置による各色の色ずれ補正用パターンにあっては一旦前記転写体上に転写したうえでその色ずれ補正用パターンを前記転写体の回動移動方向最下流に配置された前記転写デバイスに通常の転写バイアスとは逆極性のバイアスを印加することによって前記転写体の回動移動方向最下流に配置された前記像担持体に転写させた後に、また、前記転写体の回動移動方向最下流に配置された前記現像装置による色の色ずれ補正用パターンにあっては前記転写体の回動移動方向最下流に配置された前記転写デバイスに通常の転写バイアスとは逆極性のバイアスを印加することによって前記転写体上に転写することなく色ずれ補正用パターンを前記転写体の回動移動方向最下流に配置された前記像担持体に保持した状態で、それぞれ、前記転写体の回動移動方向最下流に配置された前記像担持体上の色ずれ補正用パターン位置を前記光学式センサで測定して色ずれ補正を行うことを特徴とする。   The image forming apparatus according to the present invention includes a transfer body that can be rotated in the transfer material conveyance direction, and developing devices that support a plurality of colors arranged in a tandem manner along the rotation movement direction of the transfer body. A transfer device for transferring a toner image formed on each image carrier onto a transfer material conveyed by the transfer member, and a toner formed on the image carrier disposed on the most downstream side in the rotational movement direction of the transfer member An image forming apparatus comprising: an optical sensor that outputs an image position signal of an image; and a control circuit that performs color misregistration correction based on the image position signal output from the optical sensor. In the color misregistration correction pattern of each color by the developing device arranged at a position other than the most downstream in the rotational movement direction of the transfer body, the color misregistration correction pattern is temporarily transferred onto the transfer body and then the color misregistration correction pattern of the transfer body. The most downstream direction of rotation The transfer device is transferred to the image carrier disposed downstream in the rotational movement direction of the transfer body by applying a bias having a polarity opposite to a normal transfer bias to the disposed transfer device, and then the transfer device In the color misregistration correction pattern by the developing device arranged at the most downstream in the rotational movement direction of the body, a normal transfer bias is applied to the transfer device arranged at the most downstream in the rotational movement direction of the transfer body. Is a state in which a color misregistration correction pattern is held on the image carrier disposed on the most downstream side in the rotational movement direction of the transfer body without being transferred onto the transfer body by applying a reverse polarity bias, The color misregistration correction is performed by measuring the color misregistration correction pattern position on the image carrier disposed on the most downstream side in the rotational movement direction of the transfer body by the optical sensor.
本発明の画像形成装置は、転写材搬送方向に順じて回動移動可能な転写体と、該転写体の回動移動方向に沿ってタンデム方式で配置された複数色対応の各現像装置により各像担持体に形成されたトナー像を転写体により搬送される転写材上に転写する転写デバイスと、前記転写体の回動移動方向最下流に配置された前記像担持体に形成されたトナー像の画像位置信号を出力する光学式センサと、該光学式センサから出力された画像位置信号に基づいて色ずれ補正を行う制御回路と、を備えた画像形成装置において、前記制御回路は、所定のタイミングで前記各現像装置からトナーを吐き出すトナー吐き出しモードを起動させると共に、前記転写体の回動移動方向最下流以外に配置された前記現像装置からの吐出トナーにあっては一旦前記転写体上に転写したうえでその吐出トナーを前記転写体の回動移動方向最下流に配置された前記転写デバイスに通常の転写バイアスとは逆極性のバイアスを印加することによって前記転写体の回動移動方向最下流に配置された前記像担持体に転写させた後に、また、前記転写体の回動移動方向最下流に配置された前記現像装置からの吐出トナーにあっては前記転写体の回動移動方向最下流に配置された前記転写デバイスに通常の転写バイアスとは逆極性のバイアスを印加することによって前記転写体上に転写することなく吐出トナーを前記転写体の回動移動方向最下流に配置された前記像担持体に保持した状態で、それぞれ、前記転写体の回動移動方向最下流に配置された前記像担持体上の吐出トナー位置を前記光学式センサで測定して色ずれ補正を行うことを特徴とする。   The image forming apparatus according to the present invention includes a transfer body that can be rotated in the transfer material conveyance direction, and developing devices that support a plurality of colors arranged in a tandem manner along the rotation movement direction of the transfer body. A transfer device for transferring a toner image formed on each image carrier onto a transfer material conveyed by the transfer member, and a toner formed on the image carrier disposed on the most downstream side in the rotational movement direction of the transfer member An image forming apparatus comprising: an optical sensor that outputs an image position signal of an image; and a control circuit that performs color misregistration correction based on the image position signal output from the optical sensor. The toner discharge mode for discharging the toner from each of the developing devices is started at the same timing, and the toner discharged from the developing device arranged at a position other than the most downstream in the rotational movement direction of the transfer body is temporarily transferred. After the transfer toner is transferred onto the transfer device, the transfer device disposed on the most downstream side in the rotational movement direction of the transfer body is applied with a bias having a polarity opposite to that of a normal transfer bias. After the toner image is transferred to the image bearing member arranged on the most downstream side in the direction, and the toner discharged from the developing device arranged on the most downstream side in the rotational movement direction of the transfer member, the transfer member rotates. By applying a bias having a polarity opposite to that of a normal transfer bias to the transfer device arranged on the most downstream side in the movement direction, the discharged toner is moved to the most downstream side in the rotational movement direction of the transfer body without being transferred onto the transfer body. While being held by the arranged image carrier, the discharge toner position on the image carrier arranged on the most downstream side in the rotational movement direction of the transfer member is measured by the optical sensor to compensate for color misregistration. And performing.
本発明の画像形成装置は、転写材搬送方向に順じて回動移動可能な転写体と、該転写体の回動移動方向に沿ってタンデム方式で配置された複数色対応の各現像装置により各像担持体に形成されたトナー像を転写体により搬送される転写材上に転写する転写デバイスと、前記転写体の回動移動方向最下流に配置された前記像担持体に形成されたトナー像の画像濃度信号を出力する光学式センサと、該光学式センサから出力された画像濃度信号に基づいて前記現像装置の画像濃度調整を行う制御回路と、を備えた画像形成装置において、前記制御回路は、所定のタイミングで前記現像装置からトナーを吐き出すトナー吐き出しモードを起動させると共に、前記転写体の回動移動方向最下流以外に配置された前記現像装置からの吐出トナーにあっては一旦前記転写体上に転写したうえでその吐出トナーを前記転写体の回動移動方向最下流に配置された前記転写デバイスに通常の転写バイアスとは逆極性のバイアスを印加することによって前記転写体の回動移動方向最下流に配置された前記像担持体に転写させた後に、また、前記転写体の回動移動方向最下流に配置された前記現像装置からの吐出トナーにあっては前記転写体の回動移動方向最下流に配置された前記転写デバイスに通常の転写バイアスとは逆極性のバイアスを印加することによって前記転写体上に転写することなく吐出トナーを前記転写体の回動移動方向最下流に配置された前記像担持体に保持した状態で、それぞれ、前記転写体の回動移動方向最下流に配置された前記像担持体上の吐出トナー濃度を前記光学式センサで測定して画像濃度調整を行うことを特徴とする。   The image forming apparatus according to the present invention includes a transfer body that can be rotated in the transfer material conveyance direction, and developing devices that support a plurality of colors arranged in a tandem manner along the rotation movement direction of the transfer body. A transfer device for transferring a toner image formed on each image carrier onto a transfer material conveyed by the transfer member, and a toner formed on the image carrier disposed on the most downstream side in the rotational movement direction of the transfer member An image forming apparatus comprising: an optical sensor that outputs an image density signal of an image; and a control circuit that adjusts the image density of the developing device based on the image density signal output from the optical sensor. The circuit activates a toner discharge mode that discharges toner from the developing device at a predetermined timing, and includes a discharge toner from the developing device arranged at a position other than the most downstream in the rotational movement direction of the transfer body. Once the transfer toner is transferred onto the transfer body, a bias having a polarity opposite to that of a normal transfer bias is applied to the transfer device disposed downstream of the transfer body in the rotational movement direction. The toner transferred from the developing device disposed at the most downstream side in the rotational movement direction of the transfer body is transferred to the image carrier after being transferred to the downstream side in the rotational movement direction of the transfer body. By applying a bias having a polarity opposite to that of a normal transfer bias to the transfer device disposed on the most downstream side in the rotation movement direction of the body, the transfer toner is rotated without being transferred onto the transfer body. With the optical sensor, the optical sensor measures the discharged toner density on the image carrier disposed at the most downstream side in the rotational movement direction of the transfer body while being held by the image carrier disposed at the most downstream in the direction. And performs image density adjustment by.
この際、前記光学式センサよりも前記転写体の回動移動方向下流側で前記転写体上のトナー濃度を測定する第2光学式センサを備え、前記制御回路は、前記最下流に配置された像担持体上の画像濃度調整用パターンの濃度を前記光学式センサで測定すると共に、前記転写体上に残った又は転写されてしまったトナーの濃度を前記第2光学式センサで測定し、これら各センサからの測定結果に基づいて画像濃度調整を行うことも可能である。   In this case, a second optical sensor that measures the toner concentration on the transfer body downstream of the optical sensor in the rotational movement direction of the transfer body is provided, and the control circuit is disposed on the most downstream side. The density of the image density adjustment pattern on the image carrier is measured by the optical sensor, and the density of the toner remaining on or transferred to the transfer body is measured by the second optical sensor. It is also possible to adjust the image density based on the measurement result from each sensor.
また、前記光学式センサの感度よりも前記第2光学式センサの感度の方が高いのが好ましい。   Moreover, it is preferable that the sensitivity of the second optical sensor is higher than the sensitivity of the optical sensor.
本発明の画像形成装置は、単位時間あたりの印字枚数やトナー消費量に影響を与えることなく、安定した画像形成処理を行うことができる。   The image forming apparatus of the present invention can perform stable image forming processing without affecting the number of printed sheets per unit time and toner consumption.
本発明の一実施形態に係る画像形成装置を示し、実施の形態1の画像形成装置としてのタンデム方式のカラープリンタの説明図である。1 illustrates an image forming apparatus according to an embodiment of the present invention, and is an explanatory diagram of a tandem color printer as an image forming apparatus according to Embodiment 1. FIG. 本発明の一実施形態に係る画像形成装置を示し、実施の形態1の画像形成装置の要部の拡大説明図である。1 illustrates an image forming apparatus according to an embodiment of the present invention, and is an enlarged explanatory view of a main part of the image forming apparatus according to Embodiment 1. FIG. 本発明の一実施形態に係る画像形成装置を示し、実施の形態1における変形例の画像形成装置としてのタンデム方式のカラープリンタの説明図である。FIG. 2 illustrates an image forming apparatus according to an embodiment of the present invention, and is an explanatory diagram of a tandem color printer as an image forming apparatus according to a modification of the first embodiment. 本発明の一実施形態に係る画像形成装置を示し、実施の形態1における変形例の画像形成装置の要部の拡大説明図である。FIG. 2 is an enlarged explanatory diagram of a main part of an image forming apparatus according to a modification of the first embodiment, showing an image forming apparatus according to an embodiment of the present invention. 本発明の一実施形態に係る画像形成装置を示し、実施の形態2の画像形成装置としてのタンデム方式のカラープリンタの説明図である。FIG. 3 illustrates an image forming apparatus according to an embodiment of the present invention, and is an explanatory diagram of a tandem color printer as an image forming apparatus according to a second embodiment. 本発明の一実施形態に係る画像形成装置を示し、実施の形態2の画像形成装置の要部の拡大説明図である。FIG. 3 is an enlarged explanatory diagram of a main part of an image forming apparatus according to a second embodiment, showing an image forming apparatus according to an embodiment of the present invention. 本発明の一実施形態に係る画像形成装置を示し、実施の形態2における変形例の画像形成装置としてのタンデム方式のカラープリンタの説明図である。FIG. 9 is an explanatory diagram of a tandem color printer as an image forming apparatus according to a modification of the second embodiment, showing an image forming apparatus according to an embodiment of the present invention. 本発明の一実施形態に係る画像形成装置を示し、実施の形態2における変形例の画像形成装置の要部の拡大説明図である。FIG. 9 is an enlarged explanatory diagram of a main part of an image forming apparatus according to a modification of the second embodiment, showing an image forming apparatus according to an embodiment of the present invention.
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.
(実施の形態1)
図1は本発明の一実施形態に係る画像形成装置を示し、実施の形態1の画像形成装置としてのタンデム方式のカラープリンタの説明図である。図2は本発明の一実施形態に係る画像形成装置を示し、実施の形態1の画像形成装置の要部の拡大説明図である。
(Embodiment 1)
FIG. 1 illustrates an image forming apparatus according to an embodiment of the present invention, and is an explanatory diagram of a tandem color printer as the image forming apparatus according to the first embodiment. FIG. 2 shows an image forming apparatus according to an embodiment of the present invention, and is an enlarged explanatory view of a main part of the image forming apparatus according to the first embodiment.
(カラープリンタ1の全体構成)
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の上方で且つ中間転写ベルト8の回動移動方向に沿ってタンデム方式で配置された各色(例えば、イエロー(Y)・マゼンダ(M)・シアン(C)・ブラック(K))対応の現像装置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)
In FIG. 1, a color printer 1 as an image forming apparatus according to an embodiment of the present invention is turned upside down on a paper feed cassette 3 that can be pulled out from one surface (for example, the front surface) of a printer main body 2 and one surface of the printer main body 2. A manually feed tray 4 that can be provided, a transport path 5 that transports transfer paper (not shown) set in the paper feed cassette 3 or the manual feed tray 4, and an upstream end of the transport path 5 are configured. A sheet feeding unit 6, a secondary transfer roller 7 disposed in the middle of the conveyance path 5, and an endless belt-shaped intermediate for forming a toner transfer image on the surface of the transfer paper in cooperation with the secondary transfer roller 7 Each color (for example, yellow (Y), magenta (M), cyan (C), etc.) arranged in a tandem manner above the transfer belt 8 and along the rotational movement direction of the intermediate transfer belt 8 above the intermediate transfer belt 8. Black (K)) A developing unit 9, a fixing unit 10 that is arranged near the end of the transport path 5 and fixes a toner transfer image formed on the surface of the transfer paper, and a fixed transfer paper from the downstream end of the transport path 5 to the printer A discharge unit 12 that discharges to the discharge tray unit 11 of the main body 2 is provided.
中間転写体としての中間転写ベルト8は、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 as an intermediate transfer member employs an elastic intermediate transfer belt using at least one elastic layer as a layer structure, and rotates between a driving roller 13, a driven roller (tension roller) 14, and a pressure roller 15. Move and move (see 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に搬送される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.
(現像装置9の構成)
現像装置9は、転写紙搬送方向に順じた中間転写ベルト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、現像装置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ドラム状の像担持体としての感光体18の表面に供給する供給部17と、中間転写ベルト8を挟んで感光体18と対向配置された一次転写デバイス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 developing device 9)
The developing devices 9 are arranged at four locations in a tandem manner along the rotational movement direction of the intermediate transfer belt 8 along the transfer paper conveyance direction, and those having substantially the same configuration are arranged. Further, the developing device 9 includes a toner container 16 that stores toner of each color, a supply unit 17 that supplies the toner stored in the toner container 16 to the surface of a photosensitive member 18 as a drum-shaped image carrier, and an intermediate transfer belt. A primary transfer device 19 disposed opposite to the photoconductor 18 across 8, a cleaning device 20 that removes residual toner and the like attached to the surface of the photoconductor 18, a static elimination device 21 that removes the charge on the photoconductor 18, A charging device 22 for charging the surface of the photoconductor 18 and an exposure device 23 for forming a predetermined electrostatic latent image on the surface of the photoconductor 18 are provided.
尚、各現像装置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現像装置9(M)、シアン用の現像装置9(C)、イエロー用の現像装置9(Y)の順で配置され、中間転写ベルト8の回動移動方向最下流となる図示右側の端部にブラック用の現像装置9(K)が配置されている。   In the present embodiment, each developing device 9 includes a magenta developing device 9 (M), a cyan developing device 9 (C), and a yellow developing device along the rotational movement direction of the intermediate transfer belt 8. The developing device 9 (K) for black is arranged at the end portion on the right side in the drawing, which is arranged in the order of the apparatus 9 (Y) and is the most downstream in the rotational movement direction of the intermediate transfer belt 8.
(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をキャリアとともに撹拌・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、転写デバイス19に印加する転写バイアスを制御する制御回路30と、転写デバイス19に印加する転写バイアスを含めた画像形成処理全般に係わる制御データを格納したROM31と、一時記憶手段としてのRAM(又はHDD)32と、を備えている。
(Configuration of supply unit 17)
As shown in FIG. 2, the supply unit 17 includes a stirring mixer 24 that stirs and charges the toner supplied from the toner container 16 together with a carrier, and a paddle mixer that stirs and conveys the two-component developer supplied from the stirring mixer 24. 25, a partition plate 26 interposed between the mixers 24, 25, and a magnetic roller 27 as a sleeve-like developer carrier having a plurality of fixed magnets arranged therein and rotatable around the periphery. A developing roller 28 as a toner carrier that forms a toner layer (not shown) by a magnetic brush (not shown) formed on the magnetic roller 27; and the height of the magnetic brush formed on the magnetic roller 27. A control blade 30 for controlling the transfer bias applied to the transfer device 19, and a control circuit 30 for controlling the transfer bias applied to the transfer device 19. Includes a ROM31 the control data stored relating to the image forming process in general, including, a RAM (or HDD) 32 as a temporary storage means.
尚、ROM31には、本発明に係わる画像濃度補正並びに色ずれ補正に関する制御データも格納されている。これにより、ROM31と制御回路30とは、本発明に係わる画像濃度補正並びに色ずれ補正を実行するマイクロコンピュータを構成している。また、制御回路30には、中間転写ベルト8の回動移動方向最下流となるブラック用の感光体18(K)に対して配置された光学式センサ33から感光体18(K)に形成されたトナー像の画像濃度信号が入力され、この入力結果に基づいてROM31に格納された本発明に係わる画像濃度補正制御データ並びに色ずれ補正制御データに基づいて画像濃度補正制御並びに色ずれ補正制御を行う。   The ROM 31 also stores control data relating to image density correction and color misregistration correction according to the present invention. Thus, the ROM 31 and the control circuit 30 constitute a microcomputer that executes image density correction and color misregistration correction according to the present invention. Further, the control circuit 30 is formed on the photosensitive member 18 (K) from the optical sensor 33 disposed with respect to the black photosensitive member 18 (K) which is the most downstream in the rotational movement direction of the intermediate transfer belt 8. The image density signal of the toner image is input, and the image density correction control and the color shift correction control are performed based on the image density correction control data and the color shift correction control data according to the present invention stored in the ROM 31 based on the input result. Do.
(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)、そのトナー像を一次転写デバイス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 photoreceptor 18 to develop the electrostatic latent image as a toner image (development process). The transfer device 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よりも中間転写ベルト8の回動移動方向下流側に配置されたクリーニングデバイス38によって除去される。   The toner remaining on the surface of the intermediate transfer belt 8 after the toner image is secondarily transferred by the secondary transfer roller 7 is arranged downstream of the secondary transfer roller 7 in the rotational movement direction of the intermediate transfer belt 8. Removed by the cleaned cleaning device 38.
(実施例)
次に、制御回路30による画像濃度補正並びに色ずれ補正の制御例(実施例1〜4)を説明する。
(Example)
Next, control examples (embodiments 1 to 4) of image density correction and color misregistration correction by the control circuit 30 will be described.
(実施例1)
制御回路30は、中間転写ベルト8の回動移動方向最下流に配置された現像装置9(K)により感光体18(K)上に画像濃度調整用パターンを印字する。
Example 1
The control circuit 30 prints an image density adjustment pattern on the photosensitive member 18 (K) by the developing device 9 (K) disposed on the most downstream side in the rotational movement direction of the intermediate transfer belt 8.
また、制御回路30は、転写デバイス19(K)に逆バイアスを印加することにより、中間転写ベルト8にトナーが転写されないようにし、光学式センサ33で感光体18(K)上のトナー濃度を測定し、その結果に応じてトナー濃度を調整する。   Further, the control circuit 30 applies a reverse bias to the transfer device 19 (K) to prevent the toner from being transferred to the intermediate transfer belt 8, and the optical sensor 33 controls the toner density on the photoconductor 18 (K). Measure and adjust the toner density according to the result.
一方、制御回路30は、例えば、中間転写ベルト8の回動移動方向最下流以外に配置された現像装置9(例えば、現像装置9(Y))により感光体18(Y)上に画像濃度調整用パターンを印字する。   On the other hand, for example, the control circuit 30 adjusts the image density on the photosensitive member 18 (Y) by the developing device 9 (for example, the developing device 9 (Y)) disposed at a position other than the most downstream in the rotational movement direction of the intermediate transfer belt 8. The pattern for printing is printed.
また、制御回路30は、転写デバイス19(Y)に正バイアスを印加することにより、中間転写ベルト8に画像濃度調整用パターンを転写する。   In addition, the control circuit 30 transfers the image density adjustment pattern to the intermediate transfer belt 8 by applying a positive bias to the transfer device 19 (Y).
そして、制御回路30は、転写デバイス19(K)に逆バイアスを印加することにより、感光体18(K)上に画像濃度調整用パターンを転写する。   Then, the control circuit 30 applies the reverse bias to the transfer device 19 (K) to transfer the image density adjustment pattern onto the photoconductor 18 (K).
この後、制御回路30は、光学式センサ33で感光体18(K)上のトナー濃度を測定し、その結果に応じてトナー濃度を調整する。   Thereafter, the control circuit 30 measures the toner density on the photoconductor 18 (K) with the optical sensor 33 and adjusts the toner density according to the result.
尚、トナー濃度の調整方法としては、現像バイアスの調整、露光量の調整、感光体の帯電電圧の調整、ガンマ補正の調整、現像剤中のトナー濃度の変更等が考えられる。   As a method for adjusting the toner density, adjustment of the developing bias, adjustment of the exposure amount, adjustment of the charging voltage of the photosensitive member, adjustment of gamma correction, change of the toner density in the developer, and the like can be considered.
(変形例1)
図3及び図4は、本発明の実施の形態1における変形例を示し、光学式センサ33よりも中間転写ベルト8の回動移動方向下流側、この例では、搬送ベルト46に対向し搬送ベルト46の回動移動方向最下流に配置された転写デバイス19(K)と転写デバイス19(K)より下流側の二次転写ローラ7との間、に中間転写ベルト8上のトナー濃度を測定する第2光学式センサ34が配置されている。また、制御回路30には、第2光学式センサ34から中間転写ベルト8上のトナー濃度信号が入力される。
(Modification 1)
3 and 4 show a modification of the first embodiment of the present invention. The intermediate transfer belt 8 is located downstream of the optical sensor 33 in the rotational movement direction, in this example, facing the conveyor belt 46 and facing the conveyor belt 46. The toner density on the intermediate transfer belt 8 is measured between the transfer device 19 (K) disposed on the most downstream side in the rotational movement direction 46 and the secondary transfer roller 7 on the downstream side of the transfer device 19 (K). A second optical sensor 34 is arranged. Further, the toner density signal on the intermediate transfer belt 8 is input from the second optical sensor 34 to the control circuit 30.
このような構成においては、制御回路30は、感光体18(K)上に画像濃度調整用パターンを印字する。   In such a configuration, the control circuit 30 prints an image density adjustment pattern on the photoreceptor 18 (K).
また、制御回路30は、転写デバイス19(K)に逆バイアスを印加することにより、中間転写ベルト8にトナーが転写されないようにし、光学式センサ33で感光体18(K)上のトナー濃度を測定する。   Further, the control circuit 30 applies a reverse bias to the transfer device 19 (K) to prevent the toner from being transferred to the intermediate transfer belt 8, and the optical sensor 33 controls the toner density on the photoconductor 18 (K). taking measurement.
この際、一部のトナーは中間転写ベルト8上に転写されてしまう可能性があるため、制御回路30は、その中間転写ベルト8上に転写されてしまったトナーの濃度を第2光学式センサ34で測定する。   At this time, since a part of the toner may be transferred onto the intermediate transfer belt 8, the control circuit 30 determines the density of the toner transferred onto the intermediate transfer belt 8 by the second optical sensor. Measure at 34.
そして、制御回路30は、これら各センサ33,34で検出された濃度を足し合わせた結果によりトナー濃度を調整する。   The control circuit 30 adjusts the toner density based on the result obtained by adding the densities detected by the sensors 33 and 34.
一方、制御回路30は、例えば、中間転写ベルト8の回動移動方向最下流以外に配置された現像装置9(例えば、現像装置9(Y))により感光体18(Y)上に画像濃度調整用パターンを印字する。   On the other hand, for example, the control circuit 30 adjusts the image density on the photosensitive member 18 (Y) by the developing device 9 (for example, the developing device 9 (Y)) disposed at a position other than the most downstream in the rotational movement direction of the intermediate transfer belt 8. The pattern for printing is printed.
また、制御回路30は、転写デバイス19(Y)に正バイアスを印加することにより、中間転写ベルト8に画像濃度調整用パターンを転写する。   In addition, the control circuit 30 transfers the image density adjustment pattern to the intermediate transfer belt 8 by applying a positive bias to the transfer device 19 (Y).
さらに、制御回路30は、転写デバイス19(K)に逆バイアスを印加することにより、感光体18(K)上に画像濃度調整用パターンを転写し、光学式センサ33で感光体18(K)上のトナー濃度を測定する。   Further, the control circuit 30 applies a reverse bias to the transfer device 19 (K) to transfer the image density adjustment pattern onto the photoconductor 18 (K), and the optical sensor 33 performs photoconductor 18 (K). Measure the toner density on the top.
この際、一部のトナーは中間転写ベルト8上に残ってしまう可能性があるため、その中間転写ベルト8上に残ってしまったトナーの濃度を第2光学式センサ34で測定する。   At this time, since some toner may remain on the intermediate transfer belt 8, the density of the toner remaining on the intermediate transfer belt 8 is measured by the second optical sensor 34.
そして、これら各センサ33,34で検出された濃度を足し合わせた結果によりトナー濃度を調整する。   Then, the toner density is adjusted based on the result obtained by adding the densities detected by the sensors 33 and 34.
尚、トナー濃度を調整する方法としては、現像バイアスの調整、露光量の調整、感光体の帯電電圧の調整、ガンマ補正の調整、現像剤中のトナー濃度の変更等が考えられる。   As a method for adjusting the toner density, adjustment of the developing bias, adjustment of the exposure amount, adjustment of the charging voltage of the photosensitive member, adjustment of gamma correction, change of the toner density in the developer, and the like can be considered.
ところで、第2光学式センサ34は、光学式センサ33と同じ感度のものを用いても良いが、より濃度補正の精度を上げるためには、光学式センサ33よりも測定するトナー量の少ない第2光学式センサ34の方の感度を上げるのが好ましい。尚、光学式センサ34の出力値からトナー濃度値への換算方法は公知の演算方法を用いることができる。   The second optical sensor 34 may have the same sensitivity as that of the optical sensor 33. However, in order to increase the accuracy of density correction, the second optical sensor 34 has a smaller amount of toner to be measured than the optical sensor 33. The sensitivity of the two-optical sensor 34 is preferably increased. As a conversion method from the output value of the optical sensor 34 to the toner density value, a known calculation method can be used.
(実施例2)
制御回路30は、感光体18(K)上に色ずれ補正用パターンを印字する。
(Example 2)
The control circuit 30 prints a color misregistration correction pattern on the photoreceptor 18 (K).
また、制御回路30は、転写デバイス19(K)に逆バイアスを印加することにより、中間転写ベルト8にトナーが転写されないようにし、光学式センサ33で感光体18(K)上のトナー位置を測定する。そして、その結果に基づいて色ずれ補正をする。   Further, the control circuit 30 applies a reverse bias to the transfer device 19 (K) to prevent the toner from being transferred to the intermediate transfer belt 8, and the optical sensor 33 sets the toner position on the photoconductor 18 (K). taking measurement. Then, color misregistration correction is performed based on the result.
一方、制御回路30は、感光体18(Y)上に色ずれ補正用パターンを印字する。   On the other hand, the control circuit 30 prints a color misregistration correction pattern on the photoreceptor 18 (Y).
また、制御回路30は、転写デバイス19(Y)に正バイアスを印加することにより、中間転写ベルト8に色ずれ補正用パターンを転写する。転写デバイス19(K)に逆バイアスを印加することにより、感光体18(K)上に色ずれ補正用パターンを転写する。光学式センサ33で感光体18(K)上のトナーの位置を測定し、その結果に基づいて色ずれを調整する。   Further, the control circuit 30 transfers the color misregistration correction pattern to the intermediate transfer belt 8 by applying a positive bias to the transfer device 19 (Y). By applying a reverse bias to the transfer device 19 (K), the color misregistration correction pattern is transferred onto the photoreceptor 18 (K). The position of the toner on the photoreceptor 18 (K) is measured by the optical sensor 33, and the color shift is adjusted based on the result.
尚、感光体18(M),18(C)についても同様の色ずれ補正を行う。この際、色ずれ補正としては、駆動ローラ4の回転速度を変更したり、露光タイミングを変更する等がある。   The same color misregistration correction is performed on the photoconductors 18 (M) and 18 (C). At this time, color misregistration correction includes changing the rotation speed of the driving roller 4 or changing the exposure timing.
(実施例3)
制御回路30は、現像装置9(K)の印字率が低い時に、現像装置9(K)から感光体18(K)上にトナーの吐き出しを行う。
(Example 3)
The control circuit 30 discharges toner from the developing device 9 (K) onto the photosensitive member 18 (K) when the printing rate of the developing device 9 (K) is low.
また、制御回路30は、転写デバイス19(K)に逆バイアスを印加することにより、中間転写ベルト8にトナーが転写されないようにし、光学式センサ33で感光体18(K)上のトナーの位置を測定し、その結果に基づいて色ずれ補正をする。   Further, the control circuit 30 applies a reverse bias to the transfer device 19 (K) so that the toner is not transferred to the intermediate transfer belt 8, and the position of the toner on the photoconductor 18 (K) is detected by the optical sensor 33. Is measured, and color misregistration correction is performed based on the result.
一方、制御回路30は、現像装置9(Y)の印字率が低い時は、現像装置9(Y)から感光体18(Y)上にトナーの吐き出しを行う。   On the other hand, when the printing rate of the developing device 9 (Y) is low, the control circuit 30 discharges toner from the developing device 9 (Y) onto the photoreceptor 18 (Y).
また、制御回路30は、転写デバイス19(Y)に正バイアスを印加することにより、中間転写ベルト8に吐出トナーを転写する。   In addition, the control circuit 30 transfers the discharged toner to the intermediate transfer belt 8 by applying a positive bias to the transfer device 19 (Y).
さらに、制御回路30は、転写デバイス19(K)に逆バイアスを印加することにより、感光体18(K)上に吐出トナーを転写する。   Further, the control circuit 30 applies the reverse bias to the transfer device 19 (K) to transfer the discharged toner onto the photoreceptor 18 (K).
また、制御回路30は、光学式センサ33で感光体18(K)上のトナーの位置を測定し、その結果に基づいて色ずれ補正をする。   Further, the control circuit 30 measures the position of the toner on the photoconductor 18 (K) with the optical sensor 33 and corrects the color misregistration based on the result.
尚、色ずれ補正の仕方としては、駆動ローラ13の回転速度を変更する、露光タイミングを変更する等がある。また、色ずれ補正は、吐出トナーだけでなく、通常の色ずれ補正と組み合わせて行っても良い。   Note that color misregistration correction includes changing the rotation speed of the drive roller 13 and changing the exposure timing. Further, the color misregistration correction may be performed in combination with normal color misregistration correction as well as the discharged toner.
(実施例4)
制御回路30は、現像装置9(K)の印字率が低い時(例えば、1%以下)に、現像装置9(K)から感光体18(K)上にトナーの吐き出しを行う。
Example 4
The control circuit 30 discharges toner from the developing device 9 (K) onto the photosensitive member 18 (K) when the printing rate of the developing device 9 (K) is low (for example, 1% or less).
また、制御回路30は、転写デバイス19(K)に逆バイアスを印加することにより、中間転写ベルト8にトナーが転写されないようにし、光学式センサ33で感光体18(K)上のトナー濃度を測定し、その結果に基づいてトナー濃度を調整する。   Further, the control circuit 30 applies a reverse bias to the transfer device 19 (K) to prevent the toner from being transferred to the intermediate transfer belt 8, and the optical sensor 33 controls the toner density on the photoconductor 18 (K). Measure and adjust the toner density based on the result.
さらに、制御回路30は、現像装置9(Y)の印字率が低い時は、現像装置9(Y)から感光体18(Y)上にトナーの吐き出しを行う。転写デバイス19(Y)に正バイアスを印加することにより、中間転写ベルト8に吐出トナーを転写する。転写デバイス19(K)に逆バイアスを印加することにより、感光体18(K)上に吐出トナーを転写する。光学式センサ33で感光体18(K)上のトナー濃度を測定し、その結果に基づいてトナー濃度を調整する。   Further, when the printing rate of the developing device 9 (Y) is low, the control circuit 30 discharges toner from the developing device 9 (Y) onto the photosensitive member 18 (Y). By applying a positive bias to the transfer device 19 (Y), the discharged toner is transferred to the intermediate transfer belt 8. By applying a reverse bias to the transfer device 19 (K), the discharged toner is transferred onto the photoreceptor 18 (K). The optical sensor 33 measures the toner density on the photoreceptor 18 (K), and adjusts the toner density based on the result.
尚、トナー濃度の調整方法としては、現像バイアスの調整、露光量の調整、感光体の帯電電圧の調整、ガンマ補正の調整、現像剤中のトナー濃度の変更等が考えられる。この際、画像濃度調整は吐出トナーだけでなく、通常の画像濃度調整と組み合わせて行っても良い。   As a method for adjusting the toner density, adjustment of the developing bias, adjustment of the exposure amount, adjustment of the charging voltage of the photosensitive member, adjustment of gamma correction, change of the toner density in the developer, and the like can be considered. At this time, the image density adjustment may be performed in combination with not only the discharged toner but also the normal image density adjustment.
(実施の形態2)
図5は本発明の一実施形態に係る画像形成装置を示し、実施の形態2の画像形成装置としてのタンデム方式のカラープリンタの説明図である。図6は本発明の一実施形態に係る画像形成装置を示し、実施の形態2の画像形成装置の要部の拡大説明図である。
(Embodiment 2)
FIG. 5 shows an image forming apparatus according to an embodiment of the present invention, and is an explanatory diagram of a tandem type color printer as the image forming apparatus of the second embodiment. FIG. 6 shows an image forming apparatus according to an embodiment of the present invention, and is an enlarged explanatory view of a main part of the image forming apparatus according to the second embodiment.
(カラープリンタ41の全体構成)
図5に示すように、本発明の一実施形態に係る画像形成装置としてのタンデム方式のカラープリンタ41は、図示しないパーソナルコンピュータやプリンタサーバ等に接続されており、そのコンピュータ等から送られてくる画像データに基づいてフルカラー画像を転写紙に転写・定着するものである。
(Overall configuration of the color printer 41)
As shown in FIG. 5, a tandem color printer 41 as an image forming apparatus according to an embodiment of the present invention is connected to a personal computer, a printer server, or the like (not shown) and is sent from the computer. A full-color image is transferred and fixed on transfer paper based on the image data.
尚、上記実施の形態1で示したカラープリンタ1と機能的に同一の構成には、同一の符号を付して、その詳細な説明は省略する。   In addition, the same code | symbol is attached | subjected to the structure same as the color printer 1 shown in the said Embodiment 1, and the detailed description is abbreviate | omitted.
また、プリンタ41は、複数段の給紙カセット3に収納された転写紙(図示せず)を転写・定着しつつ排出部12まで搬送する搬送経路5の一部を構成するように、感光体18の配置方向、即ち、転写紙搬送方向に順じて回動移動可能な転写体としての搬送ベルト48を備えている。   Further, the printer 41 forms a part of the conveyance path 5 that conveys transfer paper (not shown) stored in a plurality of stages of paper feed cassettes 3 to the discharge unit 12 while transferring and fixing the photosensitive paper. A transport belt 48 is provided as a transfer body that can be rotated and moved in the arrangement direction of 18, that is, the transfer paper transport direction.
(他の実施例)
次に、制御回路30による画像濃度補正並びに色ずれ補正の制御例(実施例5〜8)を説明する。
(Other examples)
Next, control examples (embodiments 5 to 8) of image density correction and color misregistration correction by the control circuit 30 will be described.
(実施例5)
制御回路30は、感光体18(K)上に画像濃度調整用パターンを印字する。
(Example 5)
The control circuit 30 prints an image density adjustment pattern on the photoreceptor 18 (K).
また、制御回路30は、転写デバイス19(K)に逆バイアスを印加することにより、搬送ベルト48にトナーが転写されないようにし、搬送ベルト48の回動移動方向最下流となるブラック用の感光体18(K)に対して配置された光学式センサ33で感光体18(K)上のトナー濃度を測定し、その結果に基づいてトナー濃度を調整する。   In addition, the control circuit 30 applies a reverse bias to the transfer device 19 (K) so that the toner is not transferred to the transport belt 48, and the black photoconductor that is the most downstream in the rotational movement direction of the transport belt 48. The toner density on the photosensitive member 18 (K) is measured by the optical sensor 33 arranged for 18 (K), and the toner density is adjusted based on the result.
一方、制御回路30は、感光体18(Y)上に画像濃度調整用パターンを印字する。   On the other hand, the control circuit 30 prints an image density adjustment pattern on the photoreceptor 18 (Y).
また、制御回路30は、転写デバイス19(Y)に正バイアスを印加することにより、搬送ベルト48に画像濃度調整用パターンを転写する。   Further, the control circuit 30 transfers the image density adjustment pattern onto the conveyance belt 48 by applying a positive bias to the transfer device 19 (Y).
さらに、制御回路30は、転写デバイス19(K)に逆バイアスを印加することにより、感光体18(K)上に画像濃度調整用パターンを転写する。   Further, the control circuit 30 applies the reverse bias to the transfer device 19 (K) to transfer the image density adjustment pattern onto the photoreceptor 18 (K).
これにより、制御回路30は、光学式センサ33で感光体18(K)上のトナー濃度を測定し、その結果に基づいてトナー濃度を調整する。   As a result, the control circuit 30 measures the toner density on the photoconductor 18 (K) with the optical sensor 33 and adjusts the toner density based on the result.
尚、トナー濃度の調整方法としては、現像バイアスの調整、露光量の調整、感光体の帯電電圧の調整、ガンマ補正の調整、現像剤中のトナー濃度の変更等が考えられる。   As a method for adjusting the toner density, adjustment of the developing bias, adjustment of the exposure amount, adjustment of the charging voltage of the photosensitive member, adjustment of gamma correction, change of the toner density in the developer, and the like can be considered.
(変形例2)
図7及び図8は、本発明の実施の形態2における変形例を示し、光学式センサ33よりも搬送ベルト48の回動移動方向下流側、この例では、搬送ベルト46に対向し搬送ベルト46の回動移動方向最下流に配置された転写デバイス19(K)と転写デバイス19(K)より下流側で回動移動方向最上流に配置された転写デバイス19(M)との間、に搬送ベルト48上のトナー濃度を測定する第2光学式センサ34が配置されている。また、制御回路30には、第2光学式センサ34から搬送ベルト48上のトナー濃度信号が入力される。
(Modification 2)
7 and 8 show a modification of the second embodiment of the present invention. The downstream side of the optical sensor 33 in the rotational movement direction of the conveyance belt 48, in this example, the conveyance belt 46 is opposed to the conveyance belt 46. FIG. Between the transfer device 19 (K) arranged on the most downstream side in the rotational movement direction and the transfer device 19 (M) arranged on the most upstream side in the rotational movement direction downstream from the transfer device 19 (K). A second optical sensor 34 for measuring the toner density on the belt 48 is disposed. Further, the toner density signal on the conveyor belt 48 is input from the second optical sensor 34 to the control circuit 30.
このような構成においては、制御回路30は、感光体18(K)上に画像濃度調整用パターンを印字する。   In such a configuration, the control circuit 30 prints an image density adjustment pattern on the photoreceptor 18 (K).
また、制御回路30は、転写デバイス19(K)に逆バイアスを印加することにより、搬送ベルト48にトナーが転写されないようにし、光学式センサ33で感光体18(K)上のトナー濃度を測定する。   Further, the control circuit 30 applies a reverse bias to the transfer device 19 (K) to prevent the toner from being transferred to the conveyance belt 48, and measures the toner density on the photoconductor 18 (K) with the optical sensor 33. To do.
この際、一部のトナーは搬送ベルト48上に転写されてしまう可能性があるため、制御回路30は、その搬送ベルト48上に転写されてしまったトナーの濃度を第2光学式センサ34で測定する。   At this time, since a part of the toner may be transferred onto the conveyor belt 48, the control circuit 30 uses the second optical sensor 34 to determine the density of the toner transferred onto the conveyor belt 48. taking measurement.
そして、制御回路30は、これら各センサ33,34で検出された濃度を足し合わせた結果によりトナー濃度を調整する。   The control circuit 30 adjusts the toner density based on the result obtained by adding the densities detected by the sensors 33 and 34.
一方、制御回路30は、感光体18(Y)上に画像濃度調整用パターンを印字する。   On the other hand, the control circuit 30 prints an image density adjustment pattern on the photoreceptor 18 (Y).
また、制御回路30は、転写デバイス19(Y)に正バイアスを印加することにより、搬送ベルト48に画像濃度調整用パターンを転写する。   Further, the control circuit 30 transfers the image density adjustment pattern onto the conveyance belt 48 by applying a positive bias to the transfer device 19 (Y).
さらに、制御回路30は、転写デバイス19(K)に逆バイアスを印加することにより、感光体18(K)上に画像濃度調整用パターンを転写し、光学式センサ33で感光体18(K)上のトナー濃度を測定する。   Further, the control circuit 30 applies a reverse bias to the transfer device 19 (K) to transfer the image density adjustment pattern onto the photoconductor 18 (K), and the optical sensor 33 performs photoconductor 18 (K). Measure the toner density on the top.
この際、一部のトナーは搬送ベルト48上に残ってしまう可能性があるため、その搬送ベルト48上に残ってしまったトナーの濃度を第2光学式センサ34で測定する。   At this time, there is a possibility that a part of the toner may remain on the transport belt 48, and therefore the density of the toner remaining on the transport belt 48 is measured by the second optical sensor 34.
そして、これら各センサ33,34で検出した濃度を足し合わせた結果によりトナー濃度を調整する。   Then, the toner density is adjusted based on the result obtained by adding the densities detected by the sensors 33 and 34.
尚、トナー濃度の調整方法としては、現像バイアスの調整、露光量の調整、感光体の帯電電圧の調整、ガンマ補正の調整、現像剤中のトナー濃度の変更等が考えられる。   As a method for adjusting the toner density, adjustment of the developing bias, adjustment of the exposure amount, adjustment of the charging voltage of the photosensitive member, adjustment of gamma correction, change of the toner density in the developer, and the like can be considered.
ところで、第2光学式センサ34は、光学式センサ33とで同じ感度のものを用いても良いが、より濃度補正の精度を上げるためには、光学式センサ33よりも測定するトナー量の少ない第2光学式センサ34の方の感度を上げるのが好ましい。尚、光学式センサ34の出力値からトナー濃度値への換算方法は公知の演算方法を用いることができる。   The second optical sensor 34 may have the same sensitivity as that of the optical sensor 33. However, in order to increase density correction accuracy, the amount of toner to be measured is smaller than that of the optical sensor 33. The sensitivity of the second optical sensor 34 is preferably increased. As a conversion method from the output value of the optical sensor 34 to the toner density value, a known calculation method can be used.
(実施例6)
制御回路30は、感光体18(K)上に色ずれ補正用パターンを印字する。
(Example 6)
The control circuit 30 prints a color misregistration correction pattern on the photoreceptor 18 (K).
また、制御回路30は、転写デバイス19(K)に逆バイアスを印加することにより、搬送ベルト48にトナーが転写されないようにし、光学式センサ33で感光体18(K)上のトナーの位置を測定し、その結果に基づいて色ずれ補正をする。   Further, the control circuit 30 applies a reverse bias to the transfer device 19 (K) so that the toner is not transferred to the conveyance belt 48, and the position of the toner on the photoconductor 18 (K) is detected by the optical sensor 33. Measure and correct color misregistration based on the result.
一方、制御回路30は、感光体18(Y)上の色ずれ補正用パターンを印字する。   On the other hand, the control circuit 30 prints a color misregistration correction pattern on the photoreceptor 18 (Y).
また、制御回路30は、転写デバイス19(Y)に正バイアスを印加することにより、搬送ベルト48に色ずれ補正用パターンを転写する。   In addition, the control circuit 30 applies a positive bias to the transfer device 19 (Y) to transfer the color misregistration correction pattern onto the transport belt 48.
さらに、制御回路30は、転写デバイス19(K)に逆バイアスを印加することにより、感光体18(K)上に色ずれ補正用パターンを転写する。   Further, the control circuit 30 applies a reverse bias to the transfer device 19 (K) to transfer the color misregistration correction pattern onto the photoreceptor 18 (K).
これにより、制御回路30は、光学式センサ33で感光体18(K)上のトナーの位置を測定し、その結果に基づいて色ずれ補正をする。   As a result, the control circuit 30 measures the position of the toner on the photoreceptor 18 (K) with the optical sensor 33 and corrects the color misregistration based on the result.
尚、色ずれ補正の仕方としては、駆動ローラ4の回転速度を変更する、露光タイミングを変更する等がある。   Note that color misregistration correction includes changing the rotation speed of the driving roller 4 and changing the exposure timing.
(実施例7)
制御回路30は、現像装置9(K)の印字率が低い時に、現像装置9(K)から感光体18(K)上にトナーの吐き出しを行う。
(Example 7)
The control circuit 30 discharges toner from the developing device 9 (K) onto the photosensitive member 18 (K) when the printing rate of the developing device 9 (K) is low.
また、制御回路30は、転写デバイス19(K)に逆バイアスを印加することにより、搬送ベルト48にトナーが転写されないようにし、光学式センサ33で感光体18(K)上のトナーの位置を測定し、その結果に基づいて色ずれ補正をする。   Further, the control circuit 30 applies a reverse bias to the transfer device 19 (K) so that the toner is not transferred to the conveyance belt 48, and the position of the toner on the photoconductor 18 (K) is detected by the optical sensor 33. Measure and correct color misregistration based on the result.
一方、制御回路30は、現像装置9(Y)の印字率が低い時は、現像装置9(Y)から感光体18(Y)上にトナーの吐き出しを行う。   On the other hand, when the printing rate of the developing device 9 (Y) is low, the control circuit 30 discharges toner from the developing device 9 (Y) onto the photoreceptor 18 (Y).
また、制御回路30は、転写デバイス19(Y)に正バイアスを印加することにより、搬送ベルト48に吐出トナーを転写する。   In addition, the control circuit 30 applies the positive bias to the transfer device 19 (Y) to transfer the discharged toner to the transport belt 48.
さらに、制御回路30は、転写デバイス19(K)に逆バイアスを印加することにより、感光体18(K)上に吐出トナーを転写する。   Further, the control circuit 30 applies the reverse bias to the transfer device 19 (K) to transfer the discharged toner onto the photoreceptor 18 (K).
これにより、制御回路30は、光学式センサ33で感光体18(K)上のトナーの位置を測定し、その結果に基づいて色ずれ補正をする。   As a result, the control circuit 30 measures the position of the toner on the photoreceptor 18 (K) with the optical sensor 33 and corrects the color misregistration based on the result.
尚、色ずれ補正の仕方としては、駆動ローラ4の回転速度を変更する、露光タイミングを変更する等がある。この際、色ずれ補正は吐出トナーだけでなく、通常の色ずれ補正と組み合わせて行っても良い。   Note that color misregistration correction includes changing the rotation speed of the driving roller 4 and changing the exposure timing. At this time, the color misregistration correction may be performed in combination with the normal color misregistration correction as well as the discharged toner.
(実施例8)
制御回路30は、現像装置9(K)の印字率が低い時に、現像装置9(K)から感光体18(K)上にトナーの吐き出しを行う。
(Example 8)
The control circuit 30 discharges toner from the developing device 9 (K) onto the photosensitive member 18 (K) when the printing rate of the developing device 9 (K) is low.
また、制御回路30は、転写デバイス19(K)に逆バイアスを印加することにより、搬送ベルト48にトナーが転写されないようにし、光学式センサ33で感光体18(K)上のトナー濃度を測定し、その結果に基づいてトナー濃度を調整する。   Further, the control circuit 30 applies a reverse bias to the transfer device 19 (K) to prevent the toner from being transferred to the conveyance belt 48, and measures the toner density on the photoconductor 18 (K) with the optical sensor 33. The toner density is adjusted based on the result.
一方、制御回路30は、現像装置9(Y)の印字率が低い時は、現像装置9(Y)から感光体18(Y)上にトナーの吐き出しを行う。   On the other hand, when the printing rate of the developing device 9 (Y) is low, the control circuit 30 discharges toner from the developing device 9 (Y) onto the photoreceptor 18 (Y).
また、制御回路30は、転写デバイス19(Y)に正バイアスを印加することにより、搬送ベルト48に吐出トナーを転写する。   In addition, the control circuit 30 applies the positive bias to the transfer device 19 (Y) to transfer the discharged toner to the transport belt 48.
さらに、制御回路30は、転写デバイス19(K)に逆バイアスを印加することにより、感光体18(K)上に吐出トナーを転写する。   Further, the control circuit 30 applies the reverse bias to the transfer device 19 (K) to transfer the discharged toner onto the photoreceptor 18 (K).
これにより、制御回路30は、光学式センサ33で感光体18(K)上のトナー濃度を測定し、その結果に基づいてトナー濃度を調整する。   As a result, the control circuit 30 measures the toner density on the photoconductor 18 (K) with the optical sensor 33 and adjusts the toner density based on the result.
尚、トナー濃度の調整方法としては、現像バイアスの調整、露光量の調整、感光体の帯電電圧の調整、ガンマ補正の調整、現像剤中のトナー濃度の変更等が考えられる。この際、画像濃度調整は吐出トナーだけでなく、通常の画像濃度調整と組み合わせて行っても良い。   As a method for adjusting the toner density, adjustment of the developing bias, adjustment of the exposure amount, adjustment of the charging voltage of the photosensitive member, adjustment of gamma correction, change of the toner density in the developer, and the like can be considered. At this time, the image density adjustment may be performed in combination with not only the discharged toner but also the normal image density adjustment.
ところで、上述したトナー吐出しモードとは、特に、トナーの印字率が低いと古いトナーと新しいトナーとの入れ替わりが少なくなり、トナーが劣化してしまう。   By the way, in the toner discharge mode described above, particularly when the toner printing rate is low, the replacement of the old toner with the new toner is reduced, and the toner is deteriorated.
従って、このような場合には、現像装置9内の劣化したトナーを吐き出し、新しいトナーを補給するという制御を入れることにより、現像装置9内に劣化したトナーが蓄積しないようにする。   Accordingly, in such a case, the deteriorated toner in the developing device 9 is prevented from accumulating in the developing device 9 by controlling to discharge the deteriorated toner in the developing device 9 and supply new toner.
尚、その吐出トナーは、そのまま廃棄トナーボックスに回収されていたが、上記実施例においては、その吐出トナーを有効利用して色ずれ補正に用いている。   The discharged toner is collected in the waste toner box as it is, but in the above-described embodiment, the discharged toner is effectively used for color misregistration correction.
この際、色ずれ補正は、トナー吐き出しと同時に行うので、単位時間あたりの印字枚数を下げることなく、色ずれ補正を行うことができる。   At this time, since the color misregistration correction is performed simultaneously with the toner ejection, the color misregistration correction can be performed without reducing the number of printed sheets per unit time.
また、特に使用頻度の高い低印字時には、トナー消費量を気にすることなく、頻繁に色ずれ補正を行うことができるようになり、常に色ずれの少ない画像を出力することができる。   Further, particularly during low printing that is frequently used, color misregistration correction can be performed frequently without worrying about toner consumption, and an image with little color misregistration can always be output.
ところで、上記実施の形態では、本発明の画像形成装置をタンデム方式のカラープリンタ1,41に適用して説明したが、例えば、カラー複合機のように、画像形成装置全般に適用することができることは勿論である。   In the above embodiment, the image forming apparatus of the present invention is applied to the tandem type color printers 1 and 41. However, the image forming apparatus can be applied to all image forming apparatuses such as a color multifunction peripheral. Of course.
1…カラープリンタ(画像形成装置)
8…中間転写ベルト(中間転写体)
9…現像装置
18…感光体(像担持体)
19…転写デバイス
30…制御回路
33…光学式センサ
34…第2光学式センサ
48…搬送ベルト(転写体)
1. Color printer (image forming device)
8. Intermediate transfer belt (intermediate transfer member)
9 ... Developing device 18 ... Photoconductor (image carrier)
DESCRIPTION OF SYMBOLS 19 ... Transfer device 30 ... Control circuit 33 ... Optical sensor 34 ... 2nd optical sensor 48 ... Conveyance belt (transfer body)

Claims (12)

  1. 転写材搬送方向に順じて回動移動可能な中間転写体と、該中間転写体の回動移動方向に沿ってタンデム方式で配置された複数色対応の各現像装置により各像担持体に形成されたトナー像を前記中間転写体上に転写する転写デバイスと、前記中間転写体の回動移動方向最下流に配置された前記像担持体に形成されたトナー像の画像濃度信号を出力する光学式センサと、該光学式センサから出力された画像濃度信号に基づいて前記現像装置の画像濃度調整を行う制御回路と、を備えた画像形成装置において、
    前記制御回路は、前記中間転写体の回動移動方向最下流以外に配置された前記現像装置による各色の画像濃度調整用パターンにあっては一旦前記中間転写体上に転写したうえでその画像濃度調整用パターンを前記中間転写体の回動移動方向最下流に配置された前記転写デバイスに通常の転写バイアスとは逆極性のバイアスを印加することによって前記中間転写体の回動移動方向最下流に配置された前記像担持体に転写させた後に、また、前記中間転写体の回動移動方向最下流に配置された前記現像装置による色の画像濃度調整用パターンにあっては前記中間転写体の回動移動方向最下流に配置された前記転写デバイスに通常の転写バイアスとは逆極性のバイアスを印加することによって前記中間転写体上に転写することなく画像濃度調整用パターンを前記中間転写体の回動移動方向最下流に配置された前記像担持体に保持した状態で、それぞれ、前記中間転写体の回動移動方向最下流に配置された前記像担持体上の画像濃度調整用パターン濃度を前記光学式センサで測定して画像濃度調整を行うことを特徴とする画像形成装置。
    Formed on each image carrier by an intermediate transfer member that can be rotated and moved in the transfer material conveyance direction, and developing devices for multiple colors arranged in a tandem manner along the direction of rotation of the intermediate transfer member A transfer device that transfers the toner image formed on the intermediate transfer member, and an optical device that outputs an image density signal of the toner image formed on the image carrier disposed downstream in the rotational movement direction of the intermediate transfer member In an image forming apparatus comprising: an image sensor; and a control circuit that adjusts an image density of the developing device based on an image density signal output from the optical sensor,
    The control circuit transfers the image density of the image density adjustment pattern for each color by the developing device arranged at a position other than the most downstream in the rotational movement direction of the intermediate transfer body after the image is once transferred onto the intermediate transfer body. By applying a bias having a polarity opposite to that of a normal transfer bias to the transfer device disposed at the most downstream side in the rotational movement direction of the intermediate transfer body, the adjustment pattern is placed on the downstream side in the rotational movement direction of the intermediate transfer body. In the pattern for adjusting the image density of the color by the developing device disposed at the most downstream side in the rotational movement direction of the intermediate transfer member after being transferred to the arranged image carrier, the intermediate transfer member By applying a bias having a polarity opposite to that of a normal transfer bias to the transfer device arranged on the most downstream side in the rotational movement direction, the image density adjusting pattern is not transferred onto the intermediate transfer member. On the image carrier disposed on the most downstream side in the rotational movement direction of the intermediate transfer member, respectively, in a state in which the toner image is held on the image carrier disposed on the most downstream side in the rotational movement direction of the intermediate transfer member. An image forming apparatus, wherein image density adjustment is performed by measuring a pattern density for image density adjustment with the optical sensor.
  2. 転写材搬送方向に順じて回動移動可能な中間転写体と、該中間転写体の回動移動方向に沿ってタンデム方式で配置された複数色対応の各現像装置により各像担持体に形成されたトナー像を中間転写体上に転写する転写デバイスと、前記中間転写体の回動移動方向最下流に配置された前記像担持体に形成されたトナー像の画像位置信号を出力する光学式センサと、該光学式センサから出力された画像位置信号に基づいて色ずれ補正を行う制御回路と、を備えた画像形成装置において、
    前記制御回路は、前記中間転写体の回動移動方向最下流以外に配置された前記現像装置による各色の色ずれ補正用パターンにあっては一旦前記中間転写体上に転写したうえでその色ずれ補正用パターンを前記中間転写体の回動移動方向最下流に配置された前記転写デバイスに通常の転写バイアスとは逆極性のバイアスを印加することによって前記中間転写体の回動移動方向最下流に配置された前記像担持体に転写させた後に、また、前記中間転写体の回動移動方向最下流に配置された前記現像装置による色の色ずれ補正用パターンにあっては前記中間転写体の回動移動方向最下流に配置された前記転写デバイスに通常の転写バイアスとは逆極性のバイアスを印加することによって前記中間転写体上に転写することなく色ずれ補正用パターンを前記中間転写体の回動移動方向最下流に配置された前記像担持体に保持した状態で、それぞれ、前記中間転写体の回動移動方向最下流に配置された前記像担持体上の色ずれ補正用パターン位置を前記光学式センサで測定して色ずれ補正を行うことを特徴とする画像形成装置。
    Formed on each image carrier by an intermediate transfer member that can be rotated and moved in the transfer material conveyance direction, and developing devices for multiple colors arranged in a tandem manner along the direction of rotation of the intermediate transfer member A transfer device for transferring the toner image formed on the intermediate transfer member, and an optical type for outputting an image position signal of the toner image formed on the image carrier disposed downstream in the rotational movement direction of the intermediate transfer member In an image forming apparatus comprising: a sensor; and a control circuit that performs color misregistration correction based on an image position signal output from the optical sensor.
    The control circuit is configured to transfer the color misregistration pattern of each color by the developing device arranged at a position other than the most downstream in the rotational movement direction of the intermediate transfer member, after transferring the color onto the intermediate transfer member. By applying a bias having a polarity opposite to that of a normal transfer bias to the transfer device disposed at the most downstream side in the rotational movement direction of the intermediate transfer body, the correction pattern is placed on the downstream side in the rotational movement direction of the intermediate transfer body. In the pattern for correcting color misregistration by the developing device arranged at the most downstream side in the rotational movement direction of the intermediate transfer body after being transferred to the arranged image carrier, the intermediate transfer body By applying a bias having a polarity opposite to that of a normal transfer bias to the transfer device arranged on the most downstream side in the rotational movement direction, a color misregistration correction pattern is transferred without being transferred onto the intermediate transfer body. The color misregistration on the image carrier disposed on the most downstream side in the rotational movement direction of the intermediate transfer member while being held by the image carrier disposed on the most downstream side in the rotational movement direction of the intermediate transfer member. An image forming apparatus, wherein a color misregistration correction is performed by measuring a correction pattern position with the optical sensor.
  3. 転写材搬送方向に順じて回動移動可能な中間転写体と、該中間転写体の回動移動方向に沿ってタンデム方式で配置された複数色対応の各現像装置により各像担持体に形成されたトナー像を中間転写体上に転写する転写デバイスと、前記中間転写体の回動移動方向最下流に配置された前記像担持体に形成されたトナー像の画像位置信号を出力する光学式センサと、該光学式センサから出力された画像位置信号に基づいて色ずれ補正を行う制御回路と、を備えた画像形成装置において、
    前記制御回路は、所定のタイミングで前記各現像装置からトナーを吐き出すトナー吐き出しモードを起動させると共に、前記中間転写体の回動移動方向最下流以外に配置された前記現像装置からの吐出トナーにあっては一旦前記中間転写体上に転写したうえでその吐出トナーを前記中間転写体の回動移動方向最下流に配置された前記転写デバイスに通常の転写バイアスとは逆極性のバイアスを印加することによって前記中間転写体の回動移動方向最下流に配置された前記像担持体に転写させた後に、また、前記中間転写体の回動移動方向最下流に配置された前記現像装置からの吐出トナーにあっては前記中間転写体の回動移動方向最下流に配置された前記転写デバイスに通常の転写バイアスとは逆極性のバイアスを印加することによって前記中間転写体上に転写することなく吐出トナーを前記中間転写体の回動移動方向最下流に配置された前記像担持体に保持した状態で、それぞれ、前記中間転写体の回動移動方向最下流に配置された前記像担持体上の吐出トナー位置を前記光学式センサで測定して色ずれ補正を行うことを特徴とする画像形成装置。
    Formed on each image carrier by an intermediate transfer member that can be rotated and moved in the transfer material conveyance direction, and developing devices for multiple colors arranged in a tandem manner along the direction of rotation of the intermediate transfer member A transfer device for transferring the toner image formed on the intermediate transfer member, and an optical type for outputting an image position signal of the toner image formed on the image carrier disposed downstream in the rotational movement direction of the intermediate transfer member In an image forming apparatus comprising: a sensor; and a control circuit that performs color misregistration correction based on an image position signal output from the optical sensor.
    The control circuit activates a toner discharge mode for discharging toner from each of the developing devices at a predetermined timing, and detects the discharge toner from the developing device disposed at a position other than the most downstream in the rotational movement direction of the intermediate transfer member. First, after transferring the toner onto the intermediate transfer member, a bias having a polarity opposite to that of a normal transfer bias is applied to the transfer device disposed on the most downstream side in the rotational movement direction of the intermediate transfer member. The toner discharged from the developing device disposed on the most downstream side in the rotational movement direction of the intermediate transfer body after being transferred to the image carrier disposed on the most downstream side in the rotational movement direction of the intermediate transfer body. In this case, a bias having a polarity opposite to that of a normal transfer bias is applied to the transfer device disposed at the most downstream in the rotational movement direction of the intermediate transfer member. In the state where the discharged toner is held on the image carrier disposed on the most downstream side in the rotational movement direction of the intermediate transfer body without being transferred onto the intermediate transfer body, the downstream side in the rotational movement direction of the intermediate transfer body, respectively. An image forming apparatus, wherein a color misregistration correction is performed by measuring a position of a discharged toner on the image carrier disposed on the image carrier with the optical sensor.
  4. 転写材搬送方向に順じて回動移動可能な中間転写体と、該中間転写体の回動移動方向に沿ってタンデム方式で配置された複数色対応の各現像装置により各像担持体に形成されたトナー像を中間転写体上に転写する転写デバイスと、前記中間転写体の回動移動方向最下流に配置された前記像担持体に形成されたトナー像の画像濃度信号を出力する光学式センサと、該光学式センサから出力された画像濃度信号に基づいて前記現像装置の画像濃度調整を行う制御回路と、を備えた画像形成装置において、
    前記制御回路は、所定のタイミングで前記現像装置からトナーを吐き出すトナー吐き出しモードを起動させると共に、前記中間転写体の回動移動方向最下流以外に配置された前記現像装置からの吐出トナーにあっては一旦前記中間転写体上に転写したうえでその吐出トナーを前記中間転写体の回動移動方向最下流に配置された前記転写デバイスに通常の転写バイアスとは逆極性のバイアスを印加することによって前記中間転写体の回動移動方向最下流に配置された前記像担持体に転写させた後に、また、前記中間転写体の回動移動方向最下流に配置された前記現像装置からの吐出トナーにあっては前記中間転写体の回動移動方向最下流に配置された前記転写デバイスに通常の転写バイアスとは逆極性のバイアスを印加することによって前記中間転写体上に転写することなく吐出トナーを前記中間転写体の回動移動方向最下流に配置された前記像担持体に保持した状態で、それぞれ、前記中間転写体の回動移動方向最下流に配置された前記像担持体上の吐出トナー濃度を前記光学式センサで測定して画像濃度調整を行うことを特徴とする画像形成装置。
    Formed on each image carrier by an intermediate transfer member that can be rotated and moved in the transfer material conveyance direction, and developing devices for multiple colors arranged in a tandem manner along the direction of rotation of the intermediate transfer member A transfer device for transferring the toner image formed on the intermediate transfer member, and an optical device for outputting an image density signal of the toner image formed on the image carrier disposed on the most downstream side in the rotational movement direction of the intermediate transfer member In an image forming apparatus comprising: a sensor; and a control circuit that performs image density adjustment of the developing device based on an image density signal output from the optical sensor.
    The control circuit activates a toner discharge mode that discharges toner from the developing device at a predetermined timing, and is provided for toner discharged from the developing device disposed at a position other than the most downstream in the rotational movement direction of the intermediate transfer member. Is obtained by transferring the toner onto the intermediate transfer member and applying a bias having a polarity opposite to that of a normal transfer bias to the transfer device disposed on the most downstream side in the rotational movement direction of the intermediate transfer member. After the toner image is transferred to the image carrier disposed on the most downstream side in the rotational movement direction of the intermediate transfer member, the toner discharged from the developing device disposed on the most downstream side in the rotational movement direction of the intermediate transfer member is used. In this case, by applying a bias having a polarity opposite to that of a normal transfer bias to the transfer device arranged on the most downstream side in the rotational movement direction of the intermediate transfer member, The discharged toner is held on the image carrier disposed on the most downstream side in the rotational movement direction of the intermediate transfer body without being transferred onto the transfer body, and is respectively disposed on the downstream side in the rotational movement direction of the intermediate transfer body. An image forming apparatus comprising: adjusting an image density by measuring a density of a discharged toner on the arranged image carrier with the optical sensor.
  5. 前記光学式センサよりも前記中間転写体の回動移動方向下流側で前記像担持体上のトナー濃度を測定する第2光学式センサを備え、
    前記制御回路は、前記最下流に配置された像担持体上の画像濃度調整用パターンの濃度を前記光学式センサで測定すると共に、前記中間転写体上に残った又は転写されてしまったトナーの濃度を前記第2光学式センサで測定し、これら各センサからの測定結果に基づいて画像濃度調整を行うことを特徴とする請求項1又は請求項4に記載の画像形成装置。
    A second optical sensor for measuring the toner density on the image carrier on the downstream side in the rotational movement direction of the intermediate transfer member with respect to the optical sensor;
    The control circuit measures the density of the image density adjustment pattern on the image carrier disposed on the most downstream side with the optical sensor and detects the toner remaining or transferred on the intermediate transfer body. 5. The image forming apparatus according to claim 1, wherein the image density is measured by the second optical sensor, and image density adjustment is performed based on a measurement result from each of the sensors.
  6. 前記光学式センサの感度よりも前記第2光学式センサの感度の方が高いことを特徴とする請求項5に記載の画像形成装置。   The image forming apparatus according to claim 5, wherein the sensitivity of the second optical sensor is higher than the sensitivity of the optical sensor.
  7. 転写材搬送方向に順じて回動移動可能な転写体と、該転写体の回動移動方向に沿ってタンデム方式で配置された複数色対応の各現像装置により各像担持体に形成されたトナー像を転写体により搬送される転写材上に転写する転写デバイスと、前記転写体の回動移動方向最下流に配置された前記像担持体に形成されたトナー像の画像濃度信号を出力する光学式センサと、該光学式センサから出力された画像濃度信号に基づいて前記現像装置の画像濃度調整を行う制御回路と、を備えた画像形成装置において、
    前記制御回路は、前記転写体の回動移動方向最下流以外に配置された前記現像装置による各色の画像濃度調整用パターンにあっては一旦前記転写体上に転写したうえでその画像濃度調整用パターンを前記転写体の回動移動方向最下流に配置された前記転写デバイスに通常の転写バイアスとは逆極性のバイアスを印加することによって前記転写体の回動移動方向最下流に配置された前記像担持体に転写させた後に、また、前記転写体の回動移動方向最下流に配置された前記現像装置による色の画像濃度調整用パターンにあっては前記転写体の回動移動方向最下流に配置された前記転写デバイスに通常の転写バイアスとは逆極性のバイアスを印加することによって前記転写体上に転写することなく画像濃度調整用パターンを前記転写体の回動移動方向最下流に配置された前記像担持体に保持した状態で、それぞれ、前記転写体の回動移動方向最下流に配置された前記像担持体上の画像濃度調整用パターン濃度を前記光学式センサで測定して画像濃度調整を行うことを特徴とする画像形成装置。
    Formed on each image carrier by a transfer body that can be rotated and moved in the transfer material conveyance direction, and developing devices for multiple colors arranged in a tandem manner along the rotation and movement direction of the transfer body. A transfer device that transfers a toner image onto a transfer material conveyed by a transfer body, and an image density signal of the toner image formed on the image carrier disposed on the most downstream side in the rotational movement direction of the transfer body is output. In an image forming apparatus comprising: an optical sensor; and a control circuit that performs image density adjustment of the developing device based on an image density signal output from the optical sensor.
    The control circuit temporarily transfers the image density adjustment pattern of each color by the developing device arranged at a position other than the most downstream in the rotational movement direction of the transfer body onto the transfer body and then adjusts the image density. The pattern disposed at the most downstream side in the rotational movement direction of the transfer body by applying a bias having a polarity opposite to a normal transfer bias to the transfer device disposed at the most downstream side in the rotational movement direction of the transfer body. After the image is transferred to the image carrier, and in the color image density adjustment pattern by the developing device arranged at the most downstream side in the rotational movement direction of the transfer body, the downstream side in the rotational movement direction of the transfer body. By applying a bias having a polarity opposite to that of a normal transfer bias to the transfer device arranged on the transfer device, an image density adjustment pattern is rotated and moved without being transferred onto the transfer member. The optical sensor detects the image density adjustment pattern density on the image carrier disposed on the most downstream side in the rotational movement direction of the transfer body while being held by the image carrier disposed on the most downstream side. An image forming apparatus characterized in that image density adjustment is performed by measuring with the above.
  8. 転写材搬送方向に順じて回動移動可能な転写体と、該転写体の回動移動方向に沿ってタンデム方式で配置された複数色対応の各現像装置により各像担持体に形成されたトナー像を転写体により搬送される転写材上に転写する転写デバイスと、前記転写体の回動移動方向最下流に配置された前記像担持体に形成されたトナー像の画像位置信号を出力する光学式センサと、該光学式センサから出力された画像位置信号に基づいて色ずれ補正を行う制御回路と、を備えた画像形成装置において、
    前記制御回路は、前記転写体の回動移動方向最下流以外に配置された前記現像装置による各色の色ずれ補正用パターンにあっては一旦前記転写体上に転写したうえでその色ずれ補正用パターンを前記転写体の回動移動方向最下流に配置された前記転写デバイスに通常の転写バイアスとは逆極性のバイアスを印加することによって前記転写体の回動移動方向最下流に配置された前記像担持体に転写させた後に、また、前記転写体の回動移動方向最下流に配置された前記現像装置による色の色ずれ補正用パターンにあっては前記転写体の回動移動方向最下流に配置された前記転写デバイスに通常の転写バイアスとは逆極性のバイアスを印加することによって前記転写体上に転写することなく色ずれ補正用パターンを前記転写体の回動移動方向最下流に配置された前記像担持体に保持した状態で、それぞれ、前記転写体の回動移動方向最下流に配置された前記像担持体上の色ずれ補正用パターン位置を前記光学式センサで測定して色ずれ補正を行うことを特徴とする画像形成装置。
    Formed on each image carrier by a transfer body that can be rotated and moved in the transfer material conveyance direction, and developing devices for multiple colors arranged in a tandem manner along the rotation and movement direction of the transfer body. A transfer device for transferring a toner image onto a transfer material conveyed by a transfer body, and an image position signal of the toner image formed on the image carrier disposed on the most downstream side in the rotational movement direction of the transfer body are output. In an image forming apparatus comprising: an optical sensor; and a control circuit that performs color misregistration correction based on an image position signal output from the optical sensor.
    The control circuit transfers the color misregistration correction pattern for each color by the developing device arranged at a position other than the most downstream in the rotational movement direction of the transfer body, after transferring the pattern onto the transfer body. The pattern disposed at the most downstream side in the rotational movement direction of the transfer body by applying a bias having a polarity opposite to a normal transfer bias to the transfer device disposed at the most downstream side in the rotational movement direction of the transfer body. In the pattern for correcting color misregistration of the color by the developing device disposed at the most downstream side in the rotational movement direction of the transfer body after being transferred to the image carrier, the transfer body in the rotational movement direction is the most. By applying a bias having a polarity opposite to that of a normal transfer bias to the transfer device disposed downstream, the color misregistration correction pattern is transferred to the bottom in the rotational movement direction of the transfer body without being transferred onto the transfer body. With the optical sensor, the optical sensor measures the color misalignment correction pattern position on the image carrier disposed at the most downstream side in the rotational movement direction of the transfer member. An image forming apparatus that performs color misregistration correction.
  9. 転写材搬送方向に順じて回動移動可能な転写体と、該転写体の回動移動方向に沿ってタンデム方式で配置された複数色対応の各現像装置により各像担持体に形成されたトナー像を転写体により搬送される転写材上に転写する転写デバイスと、前記転写体の回動移動方向最下流に配置された前記像担持体に形成されたトナー像の画像位置信号を出力する光学式センサと、該光学式センサから出力された画像位置信号に基づいて色ずれ補正を行う制御回路と、を備えた画像形成装置において、
    前記制御回路は、所定のタイミングで前記各現像装置からトナーを吐き出すトナー吐き出しモードを起動させると共に、前記転写体の回動移動方向最下流以外に配置された前記現像装置からの吐出トナーにあっては一旦前記転写体上に転写したうえでその吐出トナーを前記転写体の回動移動方向最下流に配置された前記転写デバイスに通常の転写バイアスとは逆極性のバイアスを印加することによって前記転写体の回動移動方向最下流に配置された前記像担持体に転写させた後に、また、前記転写体の回動移動方向最下流に配置された前記現像装置からの吐出トナーにあっては前記転写体の回動移動方向最下流に配置された前記転写デバイスに通常の転写バイアスとは逆極性のバイアスを印加することによって前記転写体上に転写することなく吐出トナーを前記転写体の回動移動方向最下流に配置された前記像担持体に保持した状態で、それぞれ、前記転写体の回動移動方向最下流に配置された前記像担持体上の吐出トナー位置を前記光学式センサで測定して色ずれ補正を行うことを特徴とする画像形成装置。
    Formed on each image carrier by a transfer body that can be rotated and moved in the transfer material conveyance direction, and developing devices for multiple colors arranged in a tandem manner along the rotation and movement direction of the transfer body. A transfer device for transferring a toner image onto a transfer material conveyed by a transfer body, and an image position signal of the toner image formed on the image carrier disposed on the most downstream side in the rotational movement direction of the transfer body are output. In an image forming apparatus comprising: an optical sensor; and a control circuit that performs color misregistration correction based on an image position signal output from the optical sensor.
    The control circuit activates a toner discharge mode for discharging toner from each of the developing devices at a predetermined timing, and is provided for toner discharged from the developing device disposed at a position other than the most downstream in the rotational movement direction of the transfer body. Transfer the toner onto the transfer body by applying a bias having a polarity opposite to that of a normal transfer bias to the transfer device disposed on the most downstream side in the rotational movement direction of the transfer body. The toner discharged from the developing device disposed on the most downstream side in the rotational movement direction of the transfer body after being transferred to the image carrier disposed on the most downstream side in the rotational movement direction of the body The transfer device arranged at the most downstream in the rotational movement direction of the transfer body is not transferred onto the transfer body by applying a bias having a polarity opposite to that of a normal transfer bias. In the state where the discharged toner is held on the image carrier arranged at the most downstream side in the rotational movement direction of the transfer body, the discharge on the image carrier arranged at the most downstream side in the rotational movement direction of the transfer body, respectively. An image forming apparatus that performs color misregistration correction by measuring a toner position with the optical sensor.
  10. 転写材搬送方向に順じて回動移動可能な転写体と、該転写体の回動移動方向に沿ってタンデム方式で配置された複数色対応の各現像装置により各像担持体に形成されたトナー像を転写体により搬送される転写材上に転写する転写デバイスと、前記転写体の回動移動方向最下流に配置された前記像担持体に形成されたトナー像の画像濃度信号を出力する光学式センサと、該光学式センサから出力された画像濃度信号に基づいて前記現像装置の画像濃度調整を行う制御回路と、を備えた画像形成装置において、
    前記制御回路は、所定のタイミングで前記現像装置からトナーを吐き出すトナー吐き出しモードを起動させると共に、前記転写体の回動移動方向最下流以外に配置された前記現像装置からの吐出トナーにあっては一旦前記転写体上に転写したうえでその吐出トナーを前記転写体の回動移動方向最下流に配置された前記転写デバイスに通常の転写バイアスとは逆極性のバイアスを印加することによって前記転写体の回動移動方向最下流に配置された前記像担持体に転写させた後に、また、前記転写体の回動移動方向最下流に配置された前記現像装置からの吐出トナーにあっては前記転写体の回動移動方向最下流に配置された前記転写デバイスに通常の転写バイアスとは逆極性のバイアスを印加することによって前記転写体上に転写することなく吐出トナーを前記転写体の回動移動方向最下流に配置された前記像担持体に保持した状態で、それぞれ、前記転写体の回動移動方向最下流に配置された前記像担持体上の吐出トナー濃度を前記光学式センサで測定して画像濃度調整を行うことを特徴とする画像形成装置。
    Formed on each image carrier by a transfer body that can be rotated and moved in the transfer material conveyance direction, and developing devices for multiple colors arranged in a tandem manner along the rotation and movement direction of the transfer body. A transfer device that transfers a toner image onto a transfer material conveyed by a transfer body, and an image density signal of the toner image formed on the image carrier disposed on the most downstream side in the rotational movement direction of the transfer body is output. In an image forming apparatus comprising: an optical sensor; and a control circuit that performs image density adjustment of the developing device based on an image density signal output from the optical sensor.
    The control circuit activates a toner discharge mode for discharging toner from the developing device at a predetermined timing, and for the toner discharged from the developing device arranged at a position other than the most downstream in the rotational movement direction of the transfer body. Once the transfer toner is transferred onto the transfer body, a bias having a polarity opposite to that of a normal transfer bias is applied to the transfer device disposed downstream of the transfer body in the rotational movement direction. The toner transferred from the developing device disposed at the most downstream side in the rotational movement direction of the transfer body is transferred to the image carrier after being transferred to the downstream side in the rotational movement direction of the transfer body. By applying a bias having a polarity opposite to that of a normal transfer bias to the transfer device arranged on the most downstream side in the rotational movement direction of the body without transferring onto the transfer body The discharged toner is held on the image carrier disposed at the most downstream side in the rotational movement direction of the transfer body, and discharged on the image carrier disposed at the most downstream side in the rotational movement direction of the transfer body. An image forming apparatus, wherein toner density is measured by the optical sensor to adjust image density.
  11. 前記光学式センサよりも前記転写体の回動移動方向下流側で前記転写体上のトナー濃度を測定する第2光学式センサを備え、
    前記制御回路は、前記最下流に配置された像担持体上の画像濃度調整用パターンの濃度を前記光学式センサで測定すると共に、前記転写体上に残った又は転写されてしまったトナーの濃度を前記第2光学式センサで測定し、これら各センサからの測定結果に基づいて画像濃度調整を行うことを特徴とする請求項7又は請求項10に記載の画像形成装置。
    A second optical sensor for measuring the toner density on the transfer body downstream of the optical sensor in the rotational movement direction of the transfer body;
    The control circuit measures the density of the image density adjustment pattern on the image carrier disposed on the most downstream side with the optical sensor, and the density of the toner remaining or transferred on the transfer body. The image forming apparatus according to claim 7, wherein the image density is measured by the second optical sensor and image density adjustment is performed based on a measurement result from each of the sensors.
  12. 前記光学式センサの感度よりも前記第2光学式センサの感度の方が高いことを特徴とする請求項11に記載の画像形成装置。   The image forming apparatus according to claim 11, wherein the sensitivity of the second optical sensor is higher than the sensitivity of the optical sensor.
JP2009032227A 2008-04-22 2009-02-16 Image forming apparatus Pending JP2009282496A (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH05188712A (en) * 1992-01-13 1993-07-30 Canon Inc Image forming device
JP2004240369A (en) * 2003-02-10 2004-08-26 Canon Inc Image forming apparatus
JP2006064897A (en) * 2004-08-26 2006-03-09 Oki Data Corp Image forming apparatus

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH05188712A (en) * 1992-01-13 1993-07-30 Canon Inc Image forming device
JP2004240369A (en) * 2003-02-10 2004-08-26 Canon Inc Image forming apparatus
JP2006064897A (en) * 2004-08-26 2006-03-09 Oki Data Corp Image forming apparatus

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