JP4943014B2 - Image forming apparatus - Google Patents
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Description
本発明は、複写機やプリンタなどの複数の感光体ドラムを使用する画像形成装置における色ずれ補正装置、あるいは回転体の位置制御装置に関する。 The present invention relates to a color misregistration correction device or a rotary body position control device in an image forming apparatus using a plurality of photosensitive drums such as a copying machine and a printer.
複数の感光体ドラムをもつ多色画像形成装置では、駆動部材である感光体駆動ギヤの歯形精度誤差や取り付け偏芯などにより、各色感光体ドラムの速度変動に伴う位置変動の偏差が各色の色ずれとなって絵に現れるという問題がある。 In a multi-color image forming apparatus having a plurality of photosensitive drums, the position variation deviation due to the speed fluctuation of each color photosensitive drum due to the tooth profile accuracy error or mounting eccentricity of the photosensitive member driving gear as a driving member is different for each color. There is a problem of appearing in the picture as a shift.
そこで、各色感光体ドラムの速度変動周期を一致させることで、色ずれ量を最小限に抑え、高画質な絵を提供する技術が考えられてきた。例えばこの速度変動周期の一致には、像担持体上に描いた位置ずれ検出パターンをパターン検出装置で読み取り、各色感光体ドラムの速度変動周期および周期ずれ量を割り出すことで、色ずれ量が最小となるような各色感光体ドラム間の位相差を求め、この情報をプロファイルとして揮発性メモリ等に記憶させ、画像形成前に各感光体ドラムの位相関係をプロファイルに倣わせる方法が知られている（特許文献１から３参照）。これらの方法では基準となる色の指定は無いが、画像形成装置としては不変の基準を定めており、位置ずれ検出パターンの検出結果を基準色とその他の色の間で演算することとなる。 In view of this, a technique has been devised in which the color fluctuation amount of each color photoconductor drum is matched to minimize the color misregistration amount and provide a high-quality picture. For example, for the coincidence of the speed fluctuation period, the position deviation detection pattern drawn on the image carrier is read by the pattern detection device, and the speed fluctuation period and the period deviation amount of each color photosensitive drum are calculated, whereby the color deviation amount is minimized. A method is known in which a phase difference between photosensitive drums of each color is obtained, this information is stored as a profile in a volatile memory or the like, and the phase relationship of each photosensitive drum is copied to the profile before image formation. (See Patent Documents 1 to 3). In these methods, there is no designation of a reference color, but the image forming apparatus defines an invariable reference, and the detection result of the misregistration detection pattern is calculated between the reference color and other colors.
ここで感光体ドラムの速度変動の振幅は、部品の精度が良い場合や取り付け条件が良い場合に変動の振幅が小さくなることがある。感光体ドラムの速度変動振幅が小さいと、他の変動成分の影響などで感光体ドラムの位相を検出することが困難となり、位相検出結果にバラツキが生じてしまう。多くの場合、複数の感光体ドラムを持つ多色画像形成装置では全色同じ構成としているため、どの色に幾らの精度の部品が装着されるか予想がつかない。そのため、もしも基準色となる感光体ドラムの速度変動が小さかった場合、それ以外の要因による速度変動のために位相の検出が困難になり、その画像形成装置における位相合わせの精度が悪くなるという問題がある。すなわち従来は、感光体ドラムの速度変動による位置ずれ変動への寄与が最も高いという想定のもとで、その後の位相検出演算を行ってきたため、感光体ドラムの駆動系列の部品精度が良い場合や組立状態が良い場合など、条件によっては感光体ドラムの速度変動の寄与が小さくなることで、機械が感光体ドラムの位相を測定するのが困難になり、測定毎で結果のバラツキが大きくなるという問題があった。特に位相差算出の基準となる感光体ドラムの位置ずれ位相検出が困難な場合、感光体ドラムの位相あわせによる色ずれ低減手法の信頼性が失われることとなっていた。
そこで本発明は、基準色をあらかじめ設定せず、機械毎にそれぞれずれ量を求める為の基準となる基準色を選定することで、像担持体の位相差検出のための演算および像担持体の位相制御にかかる時間を省略できるようにし、それにより信頼性の高い位相合わせ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。
Therefore, the present invention does not set a reference color in advance, but selects a reference color as a reference for obtaining a deviation amount for each machine, thereby calculating the phase difference of the image carrier and the image carrier. An object of the present invention is to provide an image forming apparatus capable of omitting the time required for phase control and thereby performing phase alignment with high reliability.
本発明の請求項１に係る画像形成装置は、
像担持体と、
前記像担持体に静電潜像を形成する静電潜像形成装置と、
前記像担持体上の静電潜像に基づいて可視画像を形成する現像手段と、
前記像担持体の駆動部材を係合させて前記像担持体を回転駆動する駆動手段と、
前記駆動手段の回転速度の制御を行う制御手段とを有し、
前記像担持体を記録媒体の搬送体に沿って複数個配置して電子写真プロセス部を構成し、
該電子写真プロセス部の前記複数個の像担持体に形成された前記像担持体ごとの各色の画像を、前記搬送体により搬送される単一の記録媒体上に順次重ね合わせて転写することにより、前記記録媒体上に画像を得る画像形成装置において、
前記制御手段は、前記搬送体上に描いた位置ずれ検出パターンから、前記各色の画像の相対的な位置ずれ量が最も少なくなるように前記複数の像担持体の回転位相を制御し、
また前記制御手段は、前記各色の画像の相対的な位置ずれ量を求める際に、予め得ておいた前記像担持体の回転速度変動による位置ずれ検出パターンのデータを元に、前記各色の画像の位相データがもっとも精度良く得られる色を基準色として選定する、
ことを特徴とする。
An image forming apparatus according to claim 1 of the present invention includes:
An image carrier;
An electrostatic latent image forming apparatus for forming an electrostatic latent image on the image carrier;
Developing means for forming a visible image based on an electrostatic latent image on the image carrier;
Driving means for rotating the image carrier by engaging a drive member of the image carrier;
Control means for controlling the rotational speed of the drive means,
A plurality of the image carriers are arranged along a recording medium conveyance body to constitute an electrophotographic process section,
The image of each color of each of the plurality the image carrier has been made form the image bearing member of the electrophotographic process unit, be transferred sequentially superimposed onto a single recording medium conveyed by the conveying member In the image forming apparatus for obtaining an image on the recording medium,
The control means, from the positional deviation detecting patterns drawn on the carrier, Gyoshi control the rotational phase of the relative positional deviation amount is smallest so as to the plurality of image bearing members for the respective colors of the image,
Also the control means, said in determining the relative positional deviation amount of each color of the image, based on data of the position displacement detection pattern that by the rotational speed variation of previously obtained in advance said image bearing member, wherein each color phase data of the image is selected most accurately the resulting color as a criteria color,
It is characterized by that.
同請求項２に係るものは、請求項１記載の画像形成装置において、前記制御手段は、前記像担持体の回転速度変動による前記像担持体の回転周期の位置ずれ量が最大値となる前記複数の像担持体のいずれかで前記基準色を選定することを特徴とする。
Those according to the second aspect is the image forming apparatus according to claim 1, wherein the control means, position shift amount of the rotation period of the image bearing member due to the rotational speed variation of the image carrier is the maximum value the The reference color is selected in any one of a plurality of image carriers .
同請求項３に係るものは、請求項２記載の画像形成装置において、前記制御手段は、前記像担持体の回転速度変動による前記回転周期の位置ずれ量が最大となるものが複数ある場合、これら複数の像担持体のうち、その回転周期の整数倍の周期での回転周期の位置ずれ量が少ない前記複数の像担持体のいずれかで前記基準色を選定することを特徴とする。
According to a third aspect of the present invention, in the image forming apparatus according to the second aspect, when the control unit includes a plurality of units that have a maximum amount of positional deviation of the rotation period due to a variation in the rotational speed of the image carrier, among the plurality of image bearing members, characterized by selecting said reference color at any position deviation amount is small plurality of image bearing members of the rotary cycle of an integral multiple of the period of the rotation period of that.
同請求項４係るものは、請求項３記載の画像形成装置において、前記制御手段が、前記複数の像担持体の前記回転周期の整数倍の周期による前記回転周期の位置ずれ量が最小値のもので前記基準色を選定することを特徴とする。
The claim 4 according what is the image forming apparatus according to claim 3, wherein the control means, position shift amount of the rotation period by an integral multiple of the period of the rotation period of the plurality of image bearing members is minimum And selecting the reference color.
同請求項５係るものは、請求項３または４記載の画像形成装置において、前記像担持体の回転周期の整数倍値が前記像担持体の回転周期の２倍であることを特徴とする。
According to a fifth aspect of the present invention, in the image forming apparatus according to the third or fourth aspect , an integral multiple of the rotation period of the image carrier is twice the rotation period of the image carrier.
同請求項６係るものは、請求項４または５記載の画像形成装置において、検出色の位置ずれ量の最大値が決められた設定値よりも低い場合に、前記制御手段が、検出色の相対位置ずれを求める演算を行わないことを特徴とする。 According to a sixth aspect of the present invention, in the image forming apparatus according to the fourth or fifth aspect, when the maximum value of the detected color misregistration amount is lower than a predetermined set value, the control unit detects the relative color of the detected color. It is characterized in that the calculation for obtaining the positional deviation is not performed.
同請求項７係るものは、請求項６記載の画像形成装置において、検出色の位置ずれ量の最大値が決められた設定値よりも低いものが３つあるとき、前記制御手段が、その他の色の位置ずれ量の演算を行わないことを特徴とする。 According to the seventh aspect of the present invention, in the image forming apparatus according to the sixth aspect, when there are three cases where the maximum value of the detected color misregistration amount is lower than a predetermined set value, the control means The calculation of the amount of color misregistration is not performed.
同請求項８係るものは、請求項１から７のいずれかに記載の画像形成装置において、前記各色の画像の相対的な位置ずれ量を求めるための基準色と、前記像担持体の位相差を制御するための基準色を同じにすることを特徴とする。
According to the eighth aspect of the present invention, in the image forming apparatus according to any one of the first to seventh aspects, a reference color for obtaining a relative positional shift amount of the image of each color and a phase difference of the image carrier. It is characterized in that the reference colors for controlling the same are made the same .
同請求項９係るものは、請求項１から７のいずれかに記載の画像形成装置において、前記各色の画像の相対的な位置ずれ量を求めるための基準色と、前記像担持体の位相差を制御するための基準色を異ならせることを特徴とする。
According to the ninth aspect of the present invention, in the image forming apparatus according to any one of the first to seventh aspects, a reference color for obtaining a relative positional deviation amount of the image of each color and a phase difference of the image carrier. with different reference colors for controlling characterized Rukoto.
同請求項１０係るものは、請求項１から９のいずれかに記載の画像形成装置において、少なくとも前記像担持体と前記現像手段を一体の作像ユニットであるプロセスカートリッジとしてなることを特徴とする。 According to a tenth aspect of the present invention, in the image forming apparatus according to any one of the first to ninth aspects, at least the image carrier and the developing unit are formed as a process cartridge which is an integral image forming unit. .
本発明は、基準色をあらかじめ設定せず、機械毎にそれぞれずれ量を求める為の基準となる基準色を選定することで、像担持体の位相差検出のための演算および像担持体の位相制御にかかる時間を省略可能とし、それにより各像担持体の速度変動振幅の相対差による色ずれを少なくした信頼性が高い画像形成装置を提供できる。
The present invention does not set a reference color in advance, and selects a reference color as a reference for obtaining a deviation amount for each machine, thereby calculating the phase difference of the image carrier and the phase of the image carrier. the time required for control optional and is thereby possible to provide a reliable high have an image forming apparatus with a reduced color shift due to the relative difference between the speed variation amplitude of the image carriers.
以下本発明を実施するための最良の形態を、図に示す実施例を参照して説明する。 The best mode for carrying out the present invention will be described below with reference to the embodiments shown in the drawings.
図１はタンデム型カラー画像形成装置の概略図を示す。図１はプリンタの全体構成を示す断面図、図２は感光体周りの構成を示す断面図である。図中１（１Ｙ、１Ｃ、１Ｍ、１Ｋ）は像担持体である複数の感光体ドラムで、感光体ドラム１に当接する中間転写ベルト３と、それぞれの感光体ドラム１の駆動部材である感光体ドラムギア２を係合させて回転駆動する感光体ドラム駆動モータと、複数の感光体ドラム１の軸１０の位置を検出する検出手段である位相差検出センサ５と、感光体ドラム駆動モータの軸６の動きで感光体ドラム１の回転速度を変更すること、または回転開始時間や回転停止時間を感光体ドラム１ごとに変更することにより複数の感光体ドラム１の位相を調整する制御を行う制御手段（図示せず。この種の装置が内蔵するコンピュータにより実現できる。）を有する。そしてこの画像形成装置は、制御手段により各感光体ドラム１が持つ速度変動による位置ずれ量の相対差、つまり色ずれを低減させるように感光体ドラム１の位相を制御する。図中４は中間転写ローラ、７は像担持体上画像読取センサ、８は中間転写ベルト駆動ローラ、９は２次転写ローラである。 FIG. 1 is a schematic view of a tandem type color image forming apparatus. FIG. 1 is a cross-sectional view showing the overall configuration of the printer, and FIG. 2 is a cross-sectional view showing the configuration around the photoreceptor. In the figure, reference numeral 1 (1Y, 1C, 1M, 1K) denotes a plurality of photosensitive drums that are image carriers, and an intermediate transfer belt 3 that is in contact with the photosensitive drum 1 and photosensitive members that are driving members of the respective photosensitive drums 1. A photosensitive drum drive motor that rotates by engaging the body drum gear 2; a phase difference detection sensor 5 that is a detecting means for detecting the positions of the shafts 10 of the plurality of photosensitive drums 1; and a shaft of the photosensitive drum drive motor. Control for adjusting the phase of the plurality of photosensitive drums 1 by changing the rotation speed of the photosensitive drum 1 by the movement of 6 or changing the rotation start time and rotation stop time for each photosensitive drum 1. Means (not shown, which can be realized by a computer built in this type of apparatus). In this image forming apparatus, the control unit controls the phase of the photoconductive drum 1 so as to reduce the relative difference in the amount of misregistration due to the speed variation of each photoconductive drum 1, that is, the color shift. In the figure, 4 is an intermediate transfer roller, 7 is an image reading sensor on the image carrier, 8 is an intermediate transfer belt drive roller, and 9 is a secondary transfer roller.
なお以上及び以下の説明は、用紙等の転写材上にフルカラー画像を形成するときの画像形成動作を行うものとして説明するが、単色画像、２色または３色の画像を形成することもある。また、本形態のプリンタを用いてモノクロ印刷をする場合には、ブラックの作像ユニットの感光体ドラム１上にのみ静電潜像を形成して同ユニットによって現像して用紙に転写し、定着装置で定着すればよい。また詳細な図示は省略するが、感光体とドラム１等の作像ユニットは、いわゆるプロセスカートリッジとし、感光体ドラム１だけでなく、現像ユニット、クリーニング装置、帯電ローラ等が一体の作像ユニット３０としてある。 In the above and the following explanations, it is assumed that an image forming operation is performed when a full-color image is formed on a transfer material such as paper. However, a single-color image, a two-color image, or a three-color image may be formed. When monochrome printing is performed using the printer of this embodiment, an electrostatic latent image is formed only on the photosensitive drum 1 of the black image forming unit, developed by the unit, transferred to paper, and fixed. What is necessary is just to fix with an apparatus. Although not shown in detail, the image forming unit such as the photoconductor and the drum 1 is a so-called process cartridge. The image forming unit 30 includes not only the photoconductor drum 1 but also a developing unit, a cleaning device, a charging roller, and the like. It is as.
またなお各感光体ドラム１が持つ速度変動による位置ずれを測定するためには、位置ずれ検出用のパターンを中間転写ベルトなどの無端ベルト上に描き、パターン検出センサにより描かれたパターンの位置情報から位置変動を求めることが知られており、この情報を元に各種演算を行い感光体ドラムの位相を制御することも公知である。 In addition, in order to measure the positional deviation due to the speed fluctuation of each photosensitive drum 1, a positional deviation detection pattern is drawn on an endless belt such as an intermediate transfer belt, and the positional information of the pattern drawn by the pattern detection sensor. From this information, it is known to obtain position fluctuations, and it is also known to perform various calculations based on this information to control the phase of the photosensitive drum.
感光体ドラム１の位相調整行程では、感光体ドラム１の位置を検出するセンサにより、位置ずれ検出パターンを描く際（つまり最適位相関係とする前の）、各感光体ドラム１の位相差及び、パターン検出センサから検出された位置情報から各感光体ドラムの位置変動がわかる。位置ずれ検出パターンは中間転写ベルト３の前後に各色同時に書いても、中間転写ベルト３の同じ位置に各色順番に書いてもよい。 In the phase adjustment process of the photosensitive drum 1, when a position shift detection pattern is drawn by a sensor that detects the position of the photosensitive drum 1 (that is, before the optimum phase relationship is established), the phase difference between the photosensitive drums 1 and From the position information detected by the pattern detection sensor, the position variation of each photosensitive drum can be known. The misregistration detection pattern may be written simultaneously before and after the intermediate transfer belt 3 or in the order of each color at the same position on the intermediate transfer belt 3.
中間転写ベルト３上に描かれた位置ずれ検出パターンから得られる結果は、感光体ドラム１の速度変動だけでなく、モータの速度変動やギヤのかみ合い誤差変動、ベルト駆動ローラの速度変動、ベルト厚み偏差による速度変動等、様々な要因による影響を受けている。既述のように従来は、感光体ドラム１の速度変動による位置ずれ変動への寄与が最も高いという想定のもと、その後の位相検出演算を行ってきた。そのため、感光体ドラム１の駆動系列の部品精度が良い場合や組立状態が良い場合など、条件によっては感光体ドラムの速度変動の寄与が小さくなることで、機械が感光体ドラムの位相を測定するのが困難になり、測定毎で結果のバラツキが大きくなるという問題があった。特に位相差算出の基準となる感光体ドラムの位置ずれ位相検出が困難な場合、感光体ドラムの位相あわせによる色ずれ低減手法の信頼性が失われることとなる。 The result obtained from the positional deviation detection pattern drawn on the intermediate transfer belt 3 is not only the speed fluctuation of the photosensitive drum 1, but also the speed fluctuation of the motor, the gear meshing error fluctuation, the speed fluctuation of the belt driving roller, the belt thickness. It is influenced by various factors such as speed fluctuation due to deviation. Conventionally, as described above, based on the assumption that the contribution is the highest to the place Ru good to speed change location shift fluctuation of the photosensitive drum 1, it went after that of the phase detection operation. For this reason, the machine measures the phase of the photosensitive drum by reducing the contribution of speed fluctuation of the photosensitive drum depending on conditions, such as when the accuracy of parts of the drive system of the photosensitive drum 1 is good or when the assembly state is good. There is a problem that the measurement becomes difficult and the results vary greatly from measurement to measurement. In particular, when it is difficult to detect the phase shift of the photosensitive drum, which is a reference for calculating the phase difference, the reliability of the color shift reduction method based on the phase alignment of the photosensitive drum is lost.
そこで本実施例の画像形成装置では、あらかじめ基準となる色を決めず、各感光体ドラム１間の色ずれが最も少なくなる最適位相差を演算する前に、各感光体ドラム１の位置ずれ検出パターンすべてを不揮発性メモリなどの記録媒体（図示せず）に格納し、得られたデータの中から感光体ドラム１の速度変動に注目し、この速度変動における位相データがもっとも精度良く得られる色を基準色とする。なお、この基準色の選定には例えば感光体ドラム１の位置ずれ振幅が最も大きくなるものを選択することで、より精度の高い位相あわせを行うことができる。 Therefore, in the image forming apparatus according to the present embodiment, the position shift of each photoconductive drum 1 is detected before calculating the optimum phase difference that minimizes the color shift between the photoconductive drums 1 without determining a reference color in advance. All the patterns are stored in a recording medium (not shown) such as a non-volatile memory, and attention is paid to the speed fluctuation of the photosensitive drum 1 from the obtained data, and the color with which the phase data in this speed fluctuation can be obtained with the highest accuracy. Is the reference color. For the selection of the reference color, for example, by selecting the one having the largest displacement amplitude of the photosensitive drum 1, it is possible to perform phase alignment with higher accuracy.
ここで具体的に手順を説明する。画像形成装置の感光体ドラム１が交換されたとき、あるいはユーザが手動にて選択したとき感光体ドラム１の位相調整行程が開始される。位相調整行程では、はじめに図３のような各色の位相ずれ検出パターンを中間転写ベルト３上に順次描き、パターン検知センサ（例えばセンサ７）によりパターンの絶対位置情報が機械に備わるメモリ（図示せず）に記録される。なおこのパターンは、中間転写ベルト３の速度変動による位置ずれへの影響を無効化するため、どの色もベルト３の同じ位置からパターンが描かれ始め、ベルト３の１周以上にわたりパターンを描くものとしている。 Here, the procedure will be specifically described. When the photosensitive drum 1 of the image forming apparatus is replaced or when the user manually selects the phase adjustment process of the photosensitive drum 1 is started. In the phase adjustment process, first, a phase shift detection pattern of each color as shown in FIG. 3 is sequentially drawn on the intermediate transfer belt 3, and a memory (not shown) in which the pattern absolute position information is provided by the pattern detection sensor (for example, sensor 7). ) Is recorded. In this pattern, in order to invalidate the influence on the positional deviation due to the speed fluctuation of the intermediate transfer belt 3, the pattern starts to be drawn from the same position of the belt 3 for every color, and the pattern is drawn over one or more rounds of the belt 3. It is said.
またこのとき、図４に示す各感光体ドラム１の駆動ギヤ１１に取り付けられた位置検出用のフィラー１３から、各色感光体ドラム１の現状における位相差も同時に測定されることとなる。図中１２は位置検出センサ（フォトインタラプタ）である。 At this time, the current phase difference of each color photosensitive drum 1 is also measured simultaneously from the position detection filler 13 attached to the drive gear 11 of each photosensitive drum 1 shown in FIG. In the figure, reference numeral 12 denotes a position detection sensor (photo interrupter).
次にメモリに記録されたパターン位置情報から、各色の位置ずれ変動を求める。位置ずれ変動の求め方は公知であるため省略する。そして求めた各色の位置ずれ変動から、図５の「Ｍ」のように、その振幅が最も大きいものを感光体ドラム１の位相差を求める際の基準色とする。図５において、Ｋはブラック、Ｃはシアン、Ｍはマゼンタ、Ｙはイエローの各色を表す。 Next, the positional deviation fluctuation of each color is obtained from the pattern position information recorded in the memory. Since the method for obtaining the positional deviation variation is well known, it will be omitted. Then, from the obtained positional deviation variation of each color, the one having the largest amplitude as shown by “M” in FIG. 5 is set as a reference color for obtaining the phase difference of the photosensitive drum 1. In FIG. 5, K represents black, C represents cyan, M represents magenta, and Y represents yellow.
なおこの位置情報であるが、コヒーレント積分により感光体ドラム１の１回転周期分毎にデータを足しあわせることで感光体ドラム１の速度変動成分が強調され、その他の速度変動成分が打ち消される。このデータを元に位置ずれ変動が最も大きいもの、つまり感光体ドラム１による位置変動振幅が最も大きいものを選択して基準色とすれば、より精度を高められる。またこの演算を行うために、位置ずれ検出パターンの描く距離を、感光体ドラム周長の整数倍にしておくと扱いやすい。 Note that this position information is added by data for every one rotation cycle of the photosensitive drum 1 by coherent integration, so that the speed fluctuation component of the photosensitive drum 1 is emphasized and other speed fluctuation components are canceled. If the reference color is selected by selecting the data having the largest positional deviation fluctuation based on this data, that is, the one having the largest positional fluctuation amplitude due to the photosensitive drum 1, the accuracy can be further improved. In order to perform this calculation, it is easy to handle if the distance drawn by the misregistration detection pattern is an integral multiple of the circumferential length of the photosensitive drum.
また、感光体ドラム１による位置ずれ量が概略最大となる色が複数あった場合には、次に感光体ドラム１の回転周期の整数倍の色ずれ量に注目する。感光体ドラム１は駆動伝達機構の構成やガタ等により、１回転周期の整数倍でも速度変動が生じる場合がある。この整数倍の速度変動による位置ずれ量が大きいと、図６に示すような合成波となり、本来の感光体ドラム１回転の位相に比べて位相がずれて検知されてしまう恐れがある。このことから、感光体ドラム１の１回転周期の整数倍の色ずれ量は少ない方が精度良い位相を検出できる。また、この整数倍における位置ずれ量は高次になる程振幅が小さくなる傾向にあるので、少なくとも感光体ドラム周期の２次（２倍）成分による位置ずれ量までを考慮すれば十分である。 In addition, when there are a plurality of colors in which the amount of positional deviation due to the photosensitive drum 1 is approximately maximum, attention is next paid to the amount of color deviation that is an integral multiple of the rotation period of the photosensitive drum 1. The photosensitive drum 1 may vary in speed even if it is an integral multiple of one rotation cycle due to the structure of the drive transmission mechanism, backlash, or the like. If the amount of position shift due to this integral multiple speed fluctuation is large, a composite wave as shown in FIG. 6 is generated, and the phase may be detected with a phase shift as compared to the original rotation of the photosensitive drum. From this, it is possible to detect the phase with higher accuracy when the color misregistration amount is an integral multiple of one rotation period of the photosensitive drum 1. Further, since the positional deviation amount at an integral multiple tends to decrease in amplitude as the order increases, it is sufficient to consider at least the positional deviation amount due to the secondary (double) component of the photosensitive drum cycle.
これまで述べてきた基準色の決定は、各感光体ドラム１間の色ずれが最も少なくなる最適位相差を求める過程の一工程である。基準色が決定された後、画像形成装置は各色位置ずれ検出パターンの相対差から、その時点の感光体ドラムの位相差における色ずれ量を割り出し、この色ずれ量が最も少ない位相差を最適位相差として、感光体ドラムの位相関係を制御する。 The determination of the reference color described so far is one step in the process of obtaining the optimum phase difference that minimizes the color shift between the photosensitive drums 1. After the reference color is determined, the image forming apparatus calculates the color misregistration amount in the phase difference of the photosensitive drum at that time from the relative difference of each color misregistration detection pattern, and determines the phase difference with the smallest color misregistration amount as the optimum position. As the phase difference, the phase relationship of the photosensitive drum is controlled.
ここで感光体ドラム１の位置ずれ変動量が小さいと位相を判断することは難しいが、色ずれに対する感光体ドラムの寄与は少なくなることに注目する。そこであらかじめ決められた値よりも感光体ドラム１の位置ずれ量（変動振幅）が小さい場合、その後の位相差検出のための演算及び感光体ドラムの位相制御を行わずに印刷動作を始めることで、演算および感光体ドラムの位相制御にかかる時間を省略できる。 Here, it is difficult to determine the phase if the variation amount of the positional deviation of the photosensitive drum 1 is small, but it is noted that the contribution of the photosensitive drum to the color deviation is reduced. Therefore, when the amount of positional deviation (fluctuation amplitude) of the photosensitive drum 1 is smaller than a predetermined value, the printing operation is started without performing calculation for subsequent phase difference detection and phase control of the photosensitive drum. The time required for the calculation and the phase control of the photosensitive drum can be omitted.
また、感光体ドラム１による位置ずれ量が最初の色から３つの色が連続してあらかじめ決められた値よりも小さい場合は、位置ずれ量の相対差を求める対象が無くなる。そこで、このような場合は最後の色の位置ずれ量を演算しないことで、位置ずれ量の演算にかかる時間を省略できる。 In addition, when the amount of positional deviation due to the photosensitive drum 1 is smaller than a predetermined value for three colors continuously from the first color, there is no object for obtaining the relative difference of the positional deviation amounts. Therefore, in such a case, the time required for calculating the positional deviation amount can be omitted by not calculating the positional deviation amount of the last color.
また前述してきた各色の相対的な位置ずれ量を求めるための基準色と、感光体ドラム１の位相を制御するための基準色を同じとすれば、演算により求められた最適位相差の数値をそのまま使用できるので、簡単に位相合わせが行える。また各色の相対的な位置ずれ量を求めるための基準色と、感光体ドラムの位相を制御するための基準色を別として扱えば、感光体ドラムの位相制御装置を従来と同様のものでできるので、コストの負担を少なくできる。例えば、色ずれ検知パターンの検出結果からＭが色ずれの基準、となった場合、それぞれの最適位相差は、Ｋ−Ｍ、Ｃ−Ｍ、Ｙ−Ｍで求められる。このとき感光体ドラムの位相制御の基準は従来通りに決められた色であれば、感光体ドラムでの位相差は、（Ｋ−Ｍ）−（Ｋ−Ｍ）、（Ｃ−Ｍ）−（Ｋ−Ｍ）、（Ｙ―Ｍ）−（ＫーＭ）となり、従来の制御手段で色ずれ最小となる制御を行える。 If the reference color for obtaining the relative displacement amount of each color described above and the reference color for controlling the phase of the photosensitive drum 1 are the same, the numerical value of the optimum phase difference obtained by the calculation can be obtained. Since it can be used as it is, phase adjustment can be performed easily. Further, if the reference color for obtaining the relative positional deviation amount of each color and the reference color for controlling the phase of the photosensitive drum are handled separately, the phase control device for the photosensitive drum can be the same as the conventional one. Therefore, the cost burden can be reduced. For example, when M becomes a reference for color misregistration from the detection result of the color misregistration detection pattern, the respective optimum phase differences are obtained by KM, CM, and YM. At this time, if the standard of phase control of the photosensitive drum is a color determined in the conventional manner, the phase difference at the photosensitive drum is (KM)-(KM), (CM)-( KM) and (YM)-(KM), and the control that minimizes the color shift can be performed by the conventional control means.
なお以上説明してきた実施例においては、使用する感光体ドラム等を図１や図７に示すようなプロセスカートリッジとして構成すれば、簡単に感光体ドラムの着脱ができ、ドラムの着脱によっても色ずれの少ない画像を得ることができる。図中２００Ａは感光体ユニット、２００Ｂは現像ユニット、２１０は現像装置、２２０は帯電装置、２３０はクリーニング装置である。 In the embodiments described above, if the photosensitive drum to be used is configured as a process cartridge as shown in FIGS. 1 and 7, the photosensitive drum can be easily attached and detached, and color misregistration can also be achieved by attaching and detaching the drum. An image with less can be obtained. In the figure, 200A is a photosensitive unit, 200B is a developing unit, 210 is a developing device, 220 is a charging device, and 230 is a cleaning device.
すなわち、像担持体に静電潜像を形成する静電潜像形成装置と、像担持体上の静電潜像に基づいて可視画像を形成する現像手段と、像担持体に駆動部材を係合させて回転駆動する駆動手段と、駆動手段の回転速度の制御を行う制御手段とを有し、搬送体に沿って複数個配置された像担持体を含む電子写真プロセス部によって形成された画像を、搬送体により搬送される単一の記録媒体上に順次重ね合わせて転写することにより記録媒体上に画像を得る画像形成装置において、搬送体上に描いた位置ずれ検出パターンから各色の位置ずれ情報を検出し、不揮発性メモリ等の記録媒体に格納することで、各像担持体の速度変動振幅の相対差による色ずれが少なくなり、高品質の印刷画像を提供できる。 That is, an electrostatic latent image forming apparatus that forms an electrostatic latent image on the image carrier, a developing unit that forms a visible image based on the electrostatic latent image on the image carrier, and a drive member on the image carrier. An image formed by an electrophotographic process unit that includes a driving unit that rotates in combination and a control unit that controls the rotational speed of the driving unit, and includes a plurality of image carriers arranged along the conveyance body. In an image forming apparatus that obtains an image on a recording medium by sequentially superimposing and transferring the image on a single recording medium conveyed by the conveyance body, the positional deviation of each color from the positional deviation detection pattern drawn on the conveyance body By detecting information and storing it in a recording medium such as a non-volatile memory, the color shift due to the relative difference in velocity fluctuation amplitude of each image carrier is reduced, and a high-quality printed image can be provided.
またこのような画像形成装置において、記録媒体に格納された位置ずれ情報から、各色の相対的な位置ずれ量を求める為の基準となる基準色を選定することで、精度の高い位相合わせを行うことができるため、前記各像担持体の速度変動振幅の相対差による色ずれと位置ずれが少なくなる。また、像担持体の回転周期による位置ずれ量の最大値から、基準色を選定することで、簡単に精度の高い位相合わせを行うことができるため、各像担持体の速度変動振幅の相対差による色ずれが少なくなる。 In such an image forming apparatus, highly accurate phase alignment is performed by selecting a reference color as a reference for obtaining a relative positional shift amount of each color from the positional shift information stored in the recording medium. Therefore, the color shift and the position shift due to the relative difference in the speed fluctuation amplitude of each image carrier are reduced. In addition, by selecting a reference color from the maximum value of the amount of displacement due to the rotation period of the image carrier, it is possible to easily perform highly accurate phase alignment. Color shift due to is reduced.
そして、基準色の位置ずれ情報と、検出色を像担持体の所定の位相差に対応するデータ数だけずらした位置ずれ情報から検出色の相対位置ずれを求める演算手段を有し、基準色に対する検出色の像担持体の位相を少なくとも１周変化させ、相対位置ずれ量の総和が最小となる場合のデータのずらし量から得られる回転位相を最適位相とし、像担持体の回転位相を最適位相と判断された位相関係に調整することで、前記各像担持体の速度変動振幅の相対差による色ずれが少なくなる。相対位置ずれ量の偏差が最小となる場合のデータのずらし量から得られる回転位相を最適位相とし、像担持体の回転位相を最適位相と判断された位相関係に調整することで、前記各像担持体の速度変動振幅の相対差による色ずれが少なくなる。検出色の位置ずれ量の最大値が決められた設定値よりも低い場合に、検出色の相対位置ずれを求める演算を行わないことで、短時間に色ずれの少ない高品位の画像作成を実現できる。 And calculating means for calculating a relative positional deviation of the detected color from the positional deviation information of the reference color and the positional deviation information obtained by shifting the detected color by the number of data corresponding to the predetermined phase difference of the image carrier. The phase of the image carrier of the detected color is changed at least once, and the rotation phase obtained from the amount of data shift when the sum of the relative displacements is minimized is the optimum phase, and the rotation phase of the image carrier is the optimum phase. By adjusting the phase relationship determined to be, the color shift due to the relative difference in the speed fluctuation amplitude of each image carrier is reduced. The rotational phase obtained from the data shift amount when the deviation of the relative positional deviation amount is minimized is set as the optimal phase, and the rotational phase of the image carrier is adjusted to the phase relationship determined to be the optimal phase, whereby each image The color shift due to the relative difference in the speed fluctuation amplitude of the carrier is reduced. When the maximum amount of detected color misregistration is lower than the set value, high-quality image creation with little color misregistration is realized in a short time by not calculating the relative misregistration of the detected color. it can.
また検出色の位置ずれ量の最大値が決められた設定値よりも低いものが３つあるとき、その他の色の位置ずれ量の演算を行わないことで、短時間に色ずれの少ない高品位の画像作成が可能になる。そして相対的な位置ずれ量を求めるための基準色と、像担持体の位相差を制御するための基準色が等しいことで、短時間に色ずれの少ない高品位の画像を作成できるし、相対的な位置ずれ量を求めるための基準色と、像担持体の位相差を制御するための基準色が異なることで、低コストで色ずれの少ない高品位の画像を形成できる。 In addition, when there are three detection color misregistration maximum values that are lower than the set value, it is possible to obtain high quality with little color misregistration in a short time by not calculating misregistration amounts of other colors. Image creation becomes possible. Since the reference color for obtaining the relative displacement amount is equal to the reference color for controlling the phase difference of the image carrier, a high-quality image with little color displacement can be created in a short time. Since the reference color for determining the amount of positional displacement and the reference color for controlling the phase difference of the image carrier are different, a high-quality image with little color shift can be formed at low cost.
１ 感光体ドラム
２ 感光体ドラムギア
３ 中間転写ベルト
４ 中間転写ローラ
５ 位相差検出センサ
６ 感光体ドラム駆動モータの軸
７ 像担持体上画像読取センサ
８ 中間転写ベルト駆動ローラ
９ ２次転写ローラ
１０ 感光体ドラムの軸
１１ 感光体ドラムギア
１２ 位置検出センサ（フォトインタラプタ）
１３ 位置検出用のフィラー
３０ 作像ユニット
２００Ａ 感光体ユニット
２００Ｂ 現像ユニット
２１０ 現像装置
２２０ 帯電装置
２３０ クリーニング装置
DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Photosensitive drum gear 3 Intermediate transfer belt 4 Intermediate transfer roller 5 Phase difference detection sensor 6 Photosensitive drum drive motor shaft 7 Image reading sensor on image carrier 8 Intermediate transfer belt drive roller 9 Secondary transfer roller 10 Photosensitive Body drum shaft 11 Photosensitive drum gear 12 Position detection sensor (photo interrupter)
13 Filler for position detection 30 Image forming unit 200A Photoconductor unit 200B Developing unit 210 Developing device 220 Charging device 230 Cleaning device
Claims (10)
前記像担持体に静電潜像を形成する静電潜像形成装置と、
前記像担持体上の静電潜像に基づいて可視画像を形成する現像手段と、
前記像担持体の駆動部材を係合させて前記像担持体を回転駆動する駆動手段と、
前記駆動手段の回転速度の制御を行う制御手段とを有し、
前記像担持体を記録媒体の搬送体に沿って複数個配置して電子写真プロセス部を構成し、
該電子写真プロセス部の前記複数個の像担持体に形成された前記像担持体ごとの各色の画像を、前記搬送体により搬送される単一の記録媒体上に順次重ね合わせて転写することにより、前記記録媒体上に画像を得る画像形成装置において、
前記制御手段は、前記搬送体上に描いた位置ずれ検出パターンから、前記各色の画像の相対的な位置ずれ量が最も少なくなるように前記複数の像担持体の回転位相を制御し、
また前記制御手段は、前記各色の画像の相対的な位置ずれ量を求める際に、予め得ておいた前記像担持体の回転速度変動による位置ずれ検出パターンのデータを元に、前記各色の画像の位相データがもっとも精度良く得られる色を基準色として選定する、
ことを特徴とする画像形成装置。 An image carrier;
An electrostatic latent image forming apparatus for forming an electrostatic latent image on the image carrier;
Developing means for forming a visible image based on an electrostatic latent image on the image carrier;
Driving means for rotating the image carrier by engaging a drive member of the image carrier;
Control means for controlling the rotational speed of the drive means,
A plurality of the image carriers are arranged along a recording medium conveyance body to constitute an electrophotographic process section,
The image of each color of each of the plurality the image carrier has been made form the image bearing member of the electrophotographic process unit, be transferred sequentially superimposed onto a single recording medium conveyed by the conveying member In the image forming apparatus for obtaining an image on the recording medium,
The control means, from the positional deviation detecting patterns drawn on the carrier, Gyoshi control the rotational phase of the relative positional deviation amount is smallest so as to the plurality of image bearing members for the respective colors of the image,
Also the control means, said in determining the relative positional deviation amount of each color of the image, based on data of the position displacement detection pattern that by the rotational speed variation of previously obtained in advance said image bearing member, wherein each color phase data of the image is selected most accurately the resulting color as a criteria color,
An image forming apparatus.
10. The image forming apparatus according to claim 1, wherein at least the image carrier and the developing unit are formed as a process cartridge which is an integrated image forming unit.
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| JP2010151947A (en) * | 2008-12-24 | 2010-07-08 | Kyocera Mita Corp | Image forming apparatus |
| JP4905517B2 (en) | 2009-07-31 | 2012-03-28 | ブラザー工業株式会社 | Image forming apparatus |
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