JP2001134034A - Device for detecting deviation of color image forming position and image forming device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for detecting the deviation of a color image forming position and an image forming device using the same capable of not only drastically reducing the detection error of a pattern for detection caused by the rotation fluctuation of an intermediate transfer body or an image carrier but also accurately detecting the deviation of a color registration associated with the sampling of the pattern for detection without causing the complication of constitution and drastic cost rising. SOLUTION: At least two marks of the pattern for detecting the deviation of a color image forming position are formed in the same color, and the pattern for detecting the deviation of the color image forming position formed in the same color is detected by a pattern detection means. Based on the distance measured value of the pattern for detecting the deviation of the color image forming position formed in the same color, the error in the case of detecting the pattern for detecting the deviation of the color image forming position is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile or the like to which an electrophotographic system or an electrostatic recording system is applied, and more particularly to a color image forming apparatus. And a registration control system for controlling the registration.

[0002]

2. Description of the Related Art In recent years, color processing of documents processed in offices and the like is rapidly progressing, and image forming apparatuses such as copiers, printers, and facsimile machines that handle these documents are also rapidly being colored. At present, these color devices have been further improved in image quality and speed in accordance with higher quality and faster office processing in offices and the like. As a color device that can meet such a demand, for example, each color image of black (K), yellow (Y), magenta (M), and cyan (C) has an image forming unit, and is formed by each image forming unit. Various types of so-called tandem-type color image forming apparatuses for forming a color image by transferring multiple images having different colors onto a transfer material or an intermediate transfer body to be conveyed have been proposed and actually commercialized. .

A tandem type color image forming apparatus of this type is, for example, as follows. As shown in FIG. 14, this tandem type color image forming apparatus includes a black image forming unit 200K for forming a black (K) image and a yellow image forming unit 200Y for forming a yellow (Y) image. And a magenta image forming unit 200M for forming a magenta (M) color image
And four image forming units, a cyan image forming unit 200C for forming a cyan (C) color image. These four image forming units 200K, 200
Y, 200M, and 200C are horizontally arranged at a fixed interval from each other. Further, the toners sequentially formed by the image forming units 200K, 200Y, 200M, and 200C are provided below the black (K), yellow (Y), magenta (M), and cyan (C) image forming units. An intermediate transfer belt 201 for transferring images in a state of being superimposed on each other is arranged rotatably in the direction of the arrow. The intermediate transfer belt 201 is formed of, for example, a flexible synthetic resin film such as polyimide having a belt shape,
An endless belt is formed by connecting both ends of the synthetic resin film formed in a belt shape by means such as welding. Therefore, as shown in FIG. 15, the intermediate transfer belt 201 necessarily has a seam portion 201a which is a connection portion of the synthetic resin film.

The black (K), yellow (Y), magenta (M), and cyan (C) image forming units 200K,
200Y, 200M, and 200C are all configured similarly, and these four image forming units 200K, 200K,
In 00Y, 200M, and 200C, as described above, black, yellow, magenta, and cyan toner images are sequentially formed. Each of the image forming units 200K, 200Y, 200M,
200C includes a photosensitive drum 202. After the surface of the photosensitive drum 202 is uniformly charged by a scorotron 203 for primary charging, the image exposure device 20
By 4, the laser light for image formation is scanned and exposed according to the image information, and an electrostatic latent image is formed. The photosensitive drum 2
The electrostatic latent image formed on the surface of each of the image forming units 200K, 200Y, 200M, and 200C is
05, a visible toner image is developed by toners of black, yellow, magenta, and cyan, respectively, and these visible toner images are transferred to the transfer charger 206.
Is transferred onto the intermediate transfer belt 201 in a state of being superimposed on each other. The black, yellow, magenta, and cyan toner images that are multiply transferred onto the intermediate transfer belt 201 are collectively transferred onto transfer paper 207, and then subjected to a fixing process by a fixing device 208. ,
A color image is formed.

In FIG. 14, reference numeral 209 denotes a photoreceptor cleaner, and 210 denotes an intermediate transfer belt cleaner.

The tandem-type color image forming apparatus constructed as described above multiplexes the toner images sequentially formed by the plurality of image forming units 200K, 200Y, 200M, and 200C on the intermediate transfer member 201. Because it is a transfer method, it is possible to greatly speed up,
Image forming units 200K, 200Y, 200 for each color
M, the transfer position of the image formed by 200C is easily shifted,
The alignment of images of each color, that is, color registration, tends to frequently deteriorate, and it is difficult to maintain high image quality. This is performed as an initial operation by each of the image exposure devices 204K, 204Y, 204M, and 204C, or each of the image forming units 200K, 200Y, and 200M.
Due to manufacturing tolerance of 200C, mounting tolerance, etc.,
Further, as time elapses, the image forming units 200K, 200Y, 20Y,
This is due to thermal expansion or displacement of the members that make up 0M and 200C. Of these, changes in the internal temperature and external force are inevitable. For example, daily operations such as a supply operation of a transfer sheet and a recovery from a paper jam apply an external force to the color image forming apparatus.

Therefore, as a conventional technique, as shown in FIG. 15, a pattern 211 for detecting a color registration shift (hereinafter, abbreviated as “color registration shift”) is formed on the intermediate transfer member 201. Various techniques for sampling the color registration misregistration detection pattern 211 by the detector 212 and correcting the misregistration of the toner image of each color have already been proposed and introduced into actual machines.

[0008] As a technique for detecting these color registration deviations, when sampling a color registration deviation detection pattern, a low-cost detector is used to detect the color registration deviation with a sufficient resolution and sufficient resolution. Can be detected, for example, in JP-A-6-1187
No. 35 has already proposed this.

In the image forming apparatus disclosed in Japanese Patent Application Laid-Open No. 6-118735, as shown in FIG. 16, multicolor chevron marks 213K, 213Y... It is configured to use the combined pattern. The color registration deviation amount is detected such that when the chevron pattern 211 formed on the intermediate transfer belt 210 moves along with the movement of the intermediate transfer belt 201, both ends of the pattern 211 pass below it. Detectors 212 located at
a, 212b, these two detectors 212a,
Each interval of the pattern 211 is measured at the timing when the pattern 211 passes below 12b, and the amount of color registration deviation is detected.

[0010] As shown in FIG.
a is T1A, the time interval between the detection of the mark 213K (for example, black) of the detection reference color and the detection of the mark 213Y (for example, yellow) of the detection target color, and the detection of the mark 213Y of the detection target color. After that, the time interval between the detection of the next detection reference color mark 213K is T1.
B, the mark 213 of the detection reference color is detected by the second detector 212b.
The time interval between the detection of K and the detection of the mark 213Y of the detection target color is T2A, from the detection of the mark 213Y of the detection target color to the detection of the mark 213Y of the next predetermined detection target color. Assuming that the time interval is T2B, the color registration deviation amount Lerr in the main scanning direction and the color registration deviation amount Perr in the sub-scanning direction are described in Japanese Patent Laid-Open No. 6-11873.
As disclosed in Japanese Unexamined Patent Application Publication No. 5-5, it is calculated by the following calculation formula. Lerr = (T2A-T1A) ÷ 2 Perr = (T2B-T1B) -Lerr

The intermediate transfer belt 201 on which the detection pattern 211 is formed has a periodic fluctuation due to the eccentricity of a driving roll for driving the intermediate transfer belt 201, and the like. Each of the image forming units 200K, 200Y, 200M, and 200C that form the detection pattern 211 of each predetermined color on the top is also
The photosensitive drum 202 also has a periodic fluctuation due to eccentricity and the like. Therefore, the intermediate transfer belt 20
1, even if the detection patterns 211 of the respective colors are formed at predetermined intervals, the time intervals T1A, T1B, T1A, T1B of the mark 213K of the detection reference color and the mark 213Y of the detection target color detected by the two detectors 212a, 212b. T2A,
T2B and the like will include periodic fluctuations.

Therefore, the detection reference color mark 21
A time interval T1A between 3K and the mark 213Y of the detection target color,
If T1B, T2A, T2B, etc. are detected as they are,
The detected time intervals T1A, T1B, T2A, T2B, and the like contain periodic fluctuation components, and the color registration deviation amounts Lerr, Perr in the main scanning direction and the sub-scanning direction cannot be accurately detected.

Therefore, the detection of the detection pattern 211 is generally designed so as not to be affected by the periodic fluctuation of the color registration deviation. More specifically, the frequency (the number of repetitions and the interval) of the detection pattern 211 is set so as not to be synchronized with the frequency that is not affected by the detection, and the number of samplings is increased, or the number of samples for one period is increased. The sampling parameters are designed to be synchronized with each other, and the average of a plurality of sampled detection values is reduced to reduce the influence of the periodic color registration deviation fluctuation to calculate the final detection values.

[0014]

However, the prior art described above has the following problems. That is, as disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 6-118735, by using a pattern in which multicolor chevron marks 213 are combined as shown in FIG. The pattern 211 for detecting the color registration deviation can be detected with sufficient resolution by the price detector, and the registration deviation of the toner image of each color can be corrected to form a high-quality color image. .

However, even if the sampling parameters are designed to eliminate the influence of the specific frequency as described above,
There is a concern that the following problems may occur. That is, when there is a long-term variation represented by the cycle of the intermediate transfer belt 201, it is necessary to synchronize the sample length with this cycle, but the detection pattern 211 is changed by the seam portion 201a of the intermediate transfer belt 201 or the like. Since there is a region that cannot be formed, synchronization with a specific frequency cannot be performed, or even if synchronization is performed, as shown in FIG. 17, a seam portion 201a of the intermediate transfer belt 201, a scratch or dirt on the belt surface, etc. At a certain position (phase) due to the defect 201b
Inevitably occurs when the detection pattern 211 cannot be detected. In this case, even if a large number of detection patterns 211 are sampled and averaged to prevent the influence of the periodic color registration deviation fluctuation, a certain position (phase) can be detected. Due to the lack of the sampling data of the pattern 211, the average color registration shift amount shifts by ΔV, and the intermediate transfer belt 20
One rotation of the photosensitive drum 202, one rotation of the photosensitive drum 202, etc.
There is a problem that a detection error affected by the long cycle fluctuation occurs. Thus, the detection pattern 211
When a detection error of ΔV occurs in the sampling data of the image forming units 200K,
200Y, 200M, and 200C cannot accurately correct the registration error of a color image, and there is a problem that image quality such as color error is reduced.

Even if the frequency components that are not to be detected are designed to minimize the influence by setting the sampling parameters (frequency and number), the influence is not strictly eliminated at all, but in particular the fluctuation is not affected. When there are a large number of frequencies having large amplitudes, the averaged color registration shift amount is also shifted due to the influence of the large amplitude fluctuations, and a detection error occurs to a considerable extent.

In order to solve these problems, the production of the intermediate transfer belt and the driving roll for driving the intermediate transfer belt can be made more precise, or the intermediate transfer belt can be reduced. It is conceivable to reduce detection errors caused by rotation fluctuations of the intermediate transfer belt and the photosensitive drum by taking measures such as complicated and highly accurate feedback control for driving the belt and the photosensitive drum.

However, in this case, not only the manufacturing cost is significantly increased, but also the configuration of the apparatus becomes complicated, and in any case, a new problem is caused in that the cost is greatly increased. Further, the above-described means cannot avoid the effects of scratches, stains, and the like that are subsequently generated on the intermediate transfer belt.

Therefore, the present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide an intermediate transfer member without complicating the structure and significantly increasing the cost. The detection error of the detection pattern resulting from the rotation fluctuation of the image and the image carrier can be greatly reduced, and the detection of the color registration deviation due to the sampling of the detection pattern is performed with high accuracy. It is an object of the present invention to provide an image forming apparatus capable of performing the above.

[0020]

In order to solve the above-mentioned problems, the invention described in claim 1 comprises a first mark composed of a first color and a second mark composed of a second color. A color image formation position shift detection pattern including a mark and a third mark including the first color and the second color is defined as:
A color image forming position shift detecting device for detecting a color image forming position shift amount by forming the color image forming position shift detecting pattern on a surface of an object to be detected and detecting the color image forming position shift detecting pattern by pattern detection means; At least two marks of the misregistration detection pattern are formed in the same color, and the color image formation misregistration detection pattern formed in the same color is detected by the pattern detection means, and is formed in the same color. A color image forming position shift detecting device, wherein an error in detecting a color image forming position shift detecting pattern is obtained based on an interval measurement value of the color image forming position shift detecting pattern.

According to the first aspect of the present invention, at least two marks of the color image forming position deviation detecting pattern are formed in the same color, and the color image forming position deviation formed in the same color is detected. Pattern detection means for detecting a color image formation position shift detection pattern based on the interval measurement value of the color image formation position shift detection pattern formed of the same color. With such a configuration, by forming at least two marks of the color image formation position shift detection pattern in the same color, the color image formation position shift detection pattern formed in the same color has the basic Since there is no positional deviation during color image formation, a color image forming positional deviation detection pattern formed with the same color is not used. The measurement value should originally be equal to a predetermined value, and the difference between the space measurement value of the color image formation position shift detection pattern formed of the same color and the predetermined value is the color image formation position shift detection. This is a detection error when detecting the use pattern.

Therefore, by correcting the color image forming position shift detected by the color image forming position shift detecting pattern based on the detection error, the color image forming position shift can be accurately detected. It becomes possible.

According to a second aspect of the present invention, there is provided a cycle for determining an error in detecting a color image forming position deviation detecting pattern. In this cycle, all of the color image forming position deviation detecting patterns are used. A pattern for detecting a color image forming position shift formed by the same color is detected by a pattern detecting unit, and an interval between the color image forming position shift detecting patterns formed by the same color is measured. 2. The color image forming position deviation detecting device according to claim 1, wherein an error in detecting the color image forming position deviation detecting pattern is obtained based on the value.

According to the second aspect of the present invention, in the error detection cycle, the color image forming position shift detecting patterns are all formed in the same color, and the color image forming position shift formed in the same color is used. The detection pattern is detected by the pattern detection means, and an error in detecting the color image formation position shift detection pattern based on the interval measurement value of the color image formation position shift detection pattern formed in the same color is detected. Since the color image formation position shift detection patterns are all formed in the same color, the number of samples of the interval measurement values of the color image formation position shift detection patterns formed in the same color is configured. By performing processing such as averaging as necessary, a pattern for detecting a color image formation position shift can be detected. The error detection accuracy at the time of, it is possible to very high.

Further, according to a third aspect of the present invention, when a color image forming position shift is detected, the color image forming position shift detecting pattern is measured based on a measured distance between marks formed in the same color. 2. The color image forming position shift detecting device according to claim 1, wherein an error in detecting the forming position shift detecting pattern is obtained.

According to the third aspect of the present invention, when the color image forming position deviation is detected, the color image forming position deviation detecting pattern is measured based on the measured distance between marks formed in the same color. Since the configuration is such that an error in detecting the pattern for detecting the formation position deviation is determined, there is no need to provide a special error detection cycle, and the error in detecting the pattern for detecting the color image formation position deviation can be detected quickly. Therefore, it is possible to detect the amount of displacement of the color image forming position and correct the amount in a short time.

[0027] Still further, the invention described in claim 4 is:
An image forming apparatus capable of forming a color image by multiplexly transferring toner images of different colors onto an intermediate transfer body or a transfer material carried on a transfer material carrier,
A first mark of a first color, a second mark of a second color, and a first color and a second color on the intermediate transfer member or the transfer material carrier. A color image forming position shift detecting pattern composed of a third mark is formed, and the color image forming position shift detecting pattern is detected by a pattern detecting means to correct the color image forming position shift. In the image forming apparatus, at least two marks of the color image formation position shift detection pattern are formed in the same color on the intermediate transfer body or the transfer material carrier, and are formed in the same color. The color image formation position shift detection pattern is detected by the pattern detection unit, and based on the interval measurement value of the color image formation position shift detection pattern formed with the same color, An image forming apparatus characterized by obtaining an error in detecting the color image forming position shift detecting pattern.

The invention described in claim 4 has the same operation as the invention described in claim 1.

[0029]

Embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 FIG. 2 is a schematic configuration diagram showing a tandem-type color electrophotographic copying machine as an image forming apparatus according to Embodiment 1 of the present invention.

In FIG. 2, reference numeral 1 denotes a main body of a tandem type digital color copying machine, and a document reading device 4 for reading an image of a document 2 is provided on an upper portion of one end of the digital color copying machine main body. It is arranged. Further, inside the digital color copying machine main body 1, image forming units 13K, 13Y, 13M, and 13C of respective colors of black (K), yellow (Y), magenta (M), and cyan (C) are provided.
They are arranged at regular intervals along the horizontal direction.
Further, the above four image forming units 13K, 13Y,
Below 13M and 13C, an intermediate transfer belt 25 for transferring toner images of each color sequentially formed by these image forming units in a state of being superimposed on each other is arranged rotatably in the direction of the arrow. ing. Then, the toner images of the respective colors transferred in a multiplex manner on the intermediate transfer belt 25 are collectively transferred onto a transfer sheet 34 as a transfer material fed from a sheet cassette 39 or the like, and then are fixed to a fixing device 37. Is fixed on the transfer paper 34 and discharged to the outside.

FIG. 3 shows the configuration of a tandem type color electrophotographic copying machine as an image forming apparatus according to Embodiment 1 of the present invention in further detail.

Here, the configuration of the present invention will be described using a tandem type color electrophotographic copying machine, but the present invention is also effective in a color printer / facsimile. The same applies to the following second and third embodiments.

In FIG. 3, reference numeral 1 denotes a main body of a tandem-type digital color copying machine, and a platen for pressing an original 2 onto a platen glass 5 is provided on an upper portion of one end of the digital color copying machine main body 1. A cover 3 and a document reading device 4 that reads an image of the document 2 placed on the platen glass 5 are provided. The document reading device 4 illuminates a document 2 placed on a platen glass 5 with a light source 6 and reflects a reflected light image from the document 2 on a full-rate mirror 7.
And scanning and exposure on an image reading element 11 such as a CCD through a reduction optical system including half rate mirrors 8 and 9 and an image forming lens 10, and a color material reflected light image of the original 2 by the image reading element 11. A predetermined dot density (for example, 1
(6 dots / mm).

The color material reflected light image of the original 2 read by the original reading device 4 is, for example, original reflectance data of three colors of red (R), green (G), and blue (B) (8 bits each). IPS12 (Image Processes
ng System), and in this IPS 12,
Shading correction for the reflectance data of Document 2
Predetermined image processing such as position shift correction, brightness / color space conversion, gamma correction, frame erasure, color / movement editing, and the like are performed.

The image data that has been subjected to the predetermined image processing by the IPS 12 as described above is an original of four colors of yellow (Y), magenta (M), cyan (C), and black (K) (each of 8 bits). The image forming units 13K, 13Y, and 1Y are converted into color material gradation data, and each of the image forming units 13K, 13Y, and 1C of black (K), yellow (Y), magenta (M), and cyan (C) is
3M, 13C ROS 14K, 14Y, 14M, 14C
(Raster Output Scanner), and these ROS 14K, 14Y, 14M, 14C
In, image exposure with laser light is performed according to original color material gradation data of a predetermined color.

By the way, as described above, four image forming units of black (K), yellow (Y), magenta (M), and cyan (C) are provided inside the tandem type digital color copying machine body 1. 13K, 13Y, 13
M and 13C are arranged in parallel at a constant interval in the horizontal direction.

These four image forming units 13K,
13Y, 13M, and 13C have the same configuration, and are roughly divided into a photosensitive drum 15 that rotates at a predetermined rotation speed in the direction of an arrow, and a primary drum that uniformly charges the surface of the photosensitive drum 15. A scorotron 16 for charging, a ROS 14 for exposing an image corresponding to each color on the surface of the photosensitive drum 15 to form an electrostatic latent image, and a photosensitive drum 1
The developing device 17 includes a developing device 17 for developing the electrostatic latent image formed on the developing device 5 and a cleaning device 18.

As shown in FIG. 3, the ROS 14 modulates the semiconductor laser 19 according to the original color material gradation data, and emits a laser beam LB from the semiconductor laser 19 according to the gradation data. The laser beam LB emitted from the semiconductor laser 19 is deflected and scanned by the rotating polygon mirror 22 via the reflection mirrors 20 and 21, and again the image is carried via the reflection mirrors 20 and 21 and the plurality of reflection mirrors 23 and 24. Scanning exposure is performed on a photosensitive drum 15 as a body.

From the IPS 12, the ROS of the image forming units 13K, 13Y, 13M, and 13C of each color of black (K), yellow (Y), magenta (M), and cyan (C) are provided.
14K, 14Y, 14M, and 14C sequentially output image data of each color.
A laser beam LB emitted from each of the photoconductor drums 15K and 15C is emitted from each of the photoconductor drums 15K and 15C.
Scanning exposure is performed on the surfaces of Y, 15M, and 15C to form an electrostatic latent image. Each of the photosensitive drums 15K, 15Y, 15
The electrostatic latent images formed on M and 15C are the developing devices 17K and 1K.
7Y, 17M, and 17C develop toner images of black (K), yellow (Y), magenta (M), and cyan (C), respectively.

Each of the image forming units 13K, 13Y,
13M, 13C photoconductor drums 15K, 15Y, 15
The toner images of the respective colors of black (K), yellow (Y), magenta (M), and cyan (C) sequentially formed on M and 15C are image forming units 13K, 13Y, 13M, and 1M.
The primary transfer rolls 26K, 26Y, 26 are placed on an intermediate transfer belt 25 as an intermediate transfer member disposed below 3C.
M, multiplexed by 26C. The intermediate transfer belt 25 is wound around a drive roll 27, a stripping roll 28, a steering roll 29, an idle roll 30, a backup roll 31, and an idle roll 32 with a constant tension. A drive roll 27, which is rotationally driven by a dedicated drive motor having excellent constant speed (not shown), is circulated at a predetermined speed in the direction of the arrow. As the transfer belt 25, for example, an endless belt is formed by forming a synthetic resin film such as a polyimide having flexibility in a belt shape and connecting both ends of the synthetic resin film formed in a belt shape by means such as welding. What was formed in the shape is used. Therefore, as shown in FIG. 4, the intermediate transfer belt 25 necessarily has a seam portion 25a which is a connection portion of a synthetic resin film.

The toner images of each color of black (K), yellow (Y), magenta (M), and cyan (C) transferred on the transfer belt 25 in a multiplex manner are pressed against a backup roll 31 by a secondary transfer roll. The transfer paper 34 onto which the toner images of the respective colors are transferred by the secondary transfer belt 3 by the pressure contact force and the electrostatic force by the
The sheet is conveyed to the fixing device 37 by 5 and 36. And
The transfer paper 34 onto which the toner images of the respective colors have been transferred undergoes fixing processing by heat and pressure by a fixing device 37 and is discharged onto a discharge tray 38 provided outside the copying machine main body 1.

The transfer paper 34 is, as shown in FIG.
A sheet of a predetermined size from any of the plurality of sheet cassettes 39, 40, and 41 is fed to a sheet transport path 4 including a sheet feed roller 42 and a pair of sheet transport rollers 43, 44, and 45.
6, and is once conveyed to a registration roll 47.
The transfer paper 34 supplied from any of the paper feed cassettes 39, 40, and 41 is transferred to the intermediate transfer belt 2 by a registration roll 47 that is rotated at a predetermined timing.
5 sent out.

The four image forming units 13K and 13 for the above black, yellow, magenta and cyan colors
In Y, 13M, and 13C, as described above, black, yellow, magenta, and cyan toner images are sequentially formed at predetermined timings.

The photosensitive drums 15K, 15Y,
15M and 15C, after the toner image transfer step is completed,
The residual toner and paper dust are removed by the cleaning devices 18K, 18Y, 18M, and 18C to prepare for the next image forming process. Further, the residual toner is removed from the intermediate transfer belt 25 by the belt cleaner 48.

In this embodiment, a pattern for detecting a color registration deviation is formed on the intermediate transfer belt 25 at a predetermined timing, and the pattern for detecting a color registration deviation is detected. , 13
A color image is formed after correcting the color registration misregistration of Y, 13M, and 13C.

As shown in FIG. 6, the color registration misregistration detection pattern 50 includes a first chevron mark 51KK consisting of a first reference color and a second chevron mark 51KK consisting of a second color to be measured.
A pattern is used in which all the colors to be measured are combined using the third chevron mark 51YY, the third chevron mark 51KY mark including the first color and the second color, as one unit. The combination of the patterns 50 shown in FIG. 5 is one block of the reference color and the target color. When this pattern is actually used, as shown in FIG. 6, it is repeatedly formed for several blocks and sampled. Here, the first embodiment of the present invention will be described assuming a sample for one round of the intermediate transfer belt 25.

FIG. 7 is a perspective view showing the pattern detector 60 for detecting the color registration deviation.

In FIG. 7, reference numeral 61 denotes a pattern detector 60.
62a and 62b are two light emitting elements respectively illuminating the pattern 50 for color registration misregistration detection formed on the intermediate transfer belt 25, and 63a and 63b
Reference numerals 64a and 64b denote two sets of light receiving elements for receiving light reflected from different chevron marks 51 of the color registration misregistration detection pattern 50 formed on the intermediate transfer belt 25, respectively. The above two light emitting elements 62
As the light emitting elements a and 62b, for example, LEDs that emit light of a specific wavelength or light having a predetermined wavelength distribution are used. These light emitting elements 62a and 62b are provided at one detection position on the intermediate transfer belt 25. Are illuminated from opposite oblique directions that are inclined by a predetermined angle from each other. The two sets of light receiving elements 63a, 63b and 64a, 64b are arranged in such a manner that their central portions are in contact with each other and both ends are inclined downward by a predetermined angle with respect to the horizontal direction. , 63b and 64a, 6
4b, and each light receiving element 63a, 63b and 64
As shown in FIG. 1, a and 64b are set such that the detection timing and the detection angle of the reflected light are different from each other.

When the pattern detector 60 detects the color registration misregistration detection pattern 50 formed on the intermediate transfer belt 25, as shown in FIG. By 51
As shown in FIG. 8A, one of the light receiving elements 63b outputs a smooth mountain-shaped waveform first, and with some delay, the other light receiving element 63a also outputs the waveform shown in FIG. 8B. Thus, a smooth mountain-shaped waveform is output. Then, by amplifying the waveforms output from these two light receiving elements 63b and 63a and then taking the difference, or taking the difference and amplifying the difference, the waveform once becomes large as shown in FIG. 8 (c). After falling, an output waveform that rises in a large mountain shape is obtained. Therefore, the two light receiving elements 63
By calculating the difference between the waveforms output from the a and 63b, a linear mark of the color registration misregistration detection pattern 50 can be obtained as shown in FIG. 8D without using a high-precision sensor such as a CCD. 51 can be detected with high resolution and high accuracy.

FIG. 9 is a block diagram showing an embodiment of the color registration misalignment correcting apparatus according to the first embodiment.

In FIG. 9, reference numeral 70 denotes a CPU for controlling the image forming operation of the tandem-type digital color copying machine, detection and calibration of color registration deviation, and 71 a CP.
The ROM 72 stores a software program for controlling the image forming operation performed by the U70, the detection of the color registration deviation and the calibration operation, and the like.
An LED driver 73 for turning on the LEDs constituting the light emitting elements 62a and 62b of 0, and a PWM circuit (pulse width modulation circuit) 73 for controlling a threshold for sampling data by the light receiving elements 63a, 63b and 64a and 64b of the pattern detector 60 , 60 are pattern detectors for detecting color registration misregistration detection patterns formed at, for example, three places at both ends and a center part in the width direction of the intermediate transfer belt 25 (only the two ends may be formed as necessary). Reference numeral 74 denotes a counter for measuring the time interval between predetermined pulses (rising) at the time of detecting the color registration misregistration detection pattern output from the pattern detector 60 based on the reference clock pulse. Reference numeral 75 denotes a command from the CPU 70. Based on yellow (Y),
Image forming units 13Y, 13M, 13C, 13B of each color of magenta (M), cyan (C), and black (BK)
An image output circuit for outputting the image information of the document 2 or the image information for forming the color registration misregistration detection pattern 50 to the ROSs 14Y, 14M, 14C, and 14BK of K at a predetermined timing. Registration pattern storage RO storing 50 image information in advance
M are shown.

In this embodiment, the CPU
70 controls the image forming operation of the tandem-type digital color copying machine, as well as immediately after the power of the tandem-type digital color copying machine is turned on, or when the temperature in the copying machine main body 1 reaches a predetermined temperature. At a predetermined timing, such as when the above changes, when a predetermined number of copies are made by the copying machine, when the front cover is opened and closed, etc., the CPU 70 moves the intermediate transfer belt 25 onto the intermediate transfer belt 25 as shown in FIGS. The color registration misregistration detection pattern 50 is formed, the color registration misregistration detection pattern 50 is detected by the pattern detector 60, and the target image forming units 13Y and 13Y are used for the reference color pattern.
The color registration misregistration detection pattern 50 formed by M and 13C is configured to detect how much the pattern is misaligned, and to perform control for correcting the color registration misregistration.

By the way, as shown in FIG. 9, the CPU 70 controls the ROS 14 of the image forming units 13K, 13Y, 13M, 13C of each color via the image output circuit 75.
4 to 6 by outputting predetermined image information to the intermediate transfer belt 25.
The color registration misregistration detection pattern 50 shown in FIG.

The interval at which the color registration misregistration detection pattern 50 is repeatedly formed, that is, the frequency of the color registration misregistration detection pattern 50 is generally designed so as to eliminate a periodic variation in image formation. Have been. For example, when the circumferential length of the photosensitive drum 15 is 250 mm and the circumferential length of the belt driving roll 27 is 100 mm, the periodic fluctuation caused by the photosensitive drum 15 occurs every 250 mm, and the periodic fluctuation caused by the belt driving roll 27 occurs every 100 mm. Will be. In the case of a fluctuation of a relatively long period, such as the period of one rotation of the photosensitive drum 15, the period of one pattern block is shortened as much as possible, and the color registration misalignment within the fluctuation of one rotation of the photosensitive drum 15 It is desirable to set so that the detection pattern 50 is sampled as much as possible. Further, in the case of a fluctuation of a relatively short cycle as in the case of the belt driving roll 27, it is desirable to set a frequency that is asynchronous with this cycle.

At the time of actual image output, the photosensitive drum 15
In this embodiment, the frequency of the color registration misregistration detection pattern 50 is high, and the pattern 50 is asynchronous with the cycle of the belt driving roll 27. (Cycle) is set. Due to the structure of the pattern 50, the pattern is limited by the detected color registration deviation amount and the characteristics of the pattern detector 60. For example, the formation length of the minimum block that can be formed at the minimum pattern interval is 50 mm (here, the reference color and three target colors If three blocks are combined as one block), this 50 mm cycle is the highest frequency in the pattern cycle shown in FIG. 6, but is not desirable because it is synchronized with the frequency of the belt driving roll 27. Therefore, 60-70
Since the minimum block formation length of mm is not synchronized with the belt driving roll 27 and has a high frequency, this is an appropriate setting value. Assuming that one round of the intermediate transfer belt 25 is 2000 mm, 33 blocks of the color registration misregistration detection pattern 50 can be formed in one round of the belt with a block length of 60 mm. Here, the design of the block frequency of the pattern 50 has been described with respect to the two fluctuation factors of the photosensitive drum 15 and the belt driving roll 27. However, in an actual image forming apparatus, the photosensitive drum 15 and the belt driving roll 27 are driven. It is necessary to consider other fluctuation factors, such as the drive system to be used.

However, even if the design parameters of the pattern 50 are designed so as to reduce the detection error due to the periodic fluctuation, as described in the problem of the prior art, a long-period fluctuation (for example, Drum, belt, etc.), at a specific phase of a belt seam portion 25a or a defect 25b such as a scratch on the belt in that cycle,
When the color registration misregistration detection pattern 50 cannot be detected, the detection values of the main scanning direction color registration misregistration amount Lerr and the sub-scanning direction color registration misregistration amount Perr based on the color registration misregistration detection pattern 50 are: It is expected to have some detection error. For example, as shown in FIG. 10, the color registration fluctuation due to the periodic fluctuation of the photosensitive drum 15 and the intermediate transfer belt 25 is several tens to one hundred and several tens μm.
, It is considered that the detection error due to these fluctuations is about tens to several μm.

In some cases, it is difficult to set the pattern cycle of the color registration misregistration detection pattern 50 so that the effect of the periodic fluctuation caused by the photosensitive drum 15 and the intermediate transfer belt 25 is zero. In such a case, an inappropriate pattern frequency may be set to cause a large detection error.

Therefore, in this embodiment, the color registration deviation amount Lerr in the main scanning direction and the color registration deviation amount P in the sub-scanning direction based on the above-described color registration deviation detecting pattern are described.
The err detection error is reduced as follows. The procedure will be described below.

In the first embodiment, calibration of a detection error at the time of reading caused by an inappropriate pattern frequency will be described.

That is, in the first embodiment, prior to the operation of detecting the color registration deviation amount Lerr in the main scanning direction and the color registration deviation amount Perr in the sub-scanning direction based on the color registration deviation detection pattern 50, FIG. As shown in the figure, a chevron mark 51 in which all blocks of the pattern 50 for color registration misregistration detection are replaced with a single color (for example, black).
The pattern block 55 consisting of
The operation for forming the belt on the intermediate transfer belt 25 is performed at the same interval as the above.

The pattern 55 to be replaced with a single color (for example, black) formed on the intermediate transfer belt 25
Are detected by the pattern detector 60, and the time intervals T1A, T1B,
T2A, T2B are determined, and these time intervals T1A, T1
Based on B, T2A, and T2B,
Color registration deviation amount Ler in the main scanning direction for each pattern 55
r and the color registration deviation amount Perr in the sub-scanning direction are calculated. Lerr = (T2A-T1A) ÷ 2 Perr = (T2B-T1B) -Lerr

Then, over the entire circumference of the surface of the intermediate transfer belt 25, the color registration deviation amount Lerr in the main scanning direction calculated based on the blocks of the single color patterns 55 formed at a predetermined block frequency, and the sub scanning direction The value of the color registration deviation amount Perr is arithmetically averaged. Then, in the block of the single-color pattern 55 formed by the same image forming unit 13BK, the linear marks 56 of each pattern 55 should be formed on the intermediate transfer belt 25 at a predetermined interval. Belt 25 and photosensitive drum 2
5 are removed by arithmetic averaging, the resulting main scanning direction color registration deviation Lerr and the sub-scanning direction color registration deviation P
The values of err should both be zero.

Here, as shown in FIG. 10, if a deviation ΔV of about several tens to several μm is calculated, as shown in FIG. 10, the value is calculated based on the seam portion 25 a of the intermediate transfer belt 25, a scratch on the belt surface, or the like. Can be said to be a detection error caused by the defect 25b.

More specifically, the intermediate transfer belt 25
As shown in FIG. 1, the blocks of the single-color patterns 55 formed at a predetermined block frequency over the entire circumference of the surface are formed by the same image forming unit 13BK. In the blocks, there is no so-called color registration shift, and as in the case where the block of the pattern 50 is formed by the black image forming unit 13BK and the yellow image forming unit 13Y, etc.
The amount of color registration deviation Le in the main scanning direction due to a positional deviation between image forming units, a deviation in image forming timing, and the like.
rr and the color registration deviation amount Perr in the sub-scanning direction do not occur.
The value of r and the color registration deviation amount Perr in the sub-scanning direction should be originally zero.

However, when the pattern detector 60 detects a block of each pattern 55 of a single color formed on the intermediate transfer belt 25, the block is caused by rotation fluctuation of the intermediate transfer belt 25 and the photosensitive drum 15. Since the positional shift naturally occurs even in the block of each pattern 55 of the single color, the measured color registration shift amount Le in the main scanning direction is measured.
rr and the value of the color registration deviation amount Perr in the sub-scanning direction are:
As shown in FIG. 10, it fluctuates periodically.

Therefore, as shown in FIG. 1, a block of each pattern 55 of a single color is formed at a predetermined block frequency over the entire circumference of the surface of the intermediate transfer belt 25, and based on the block of each pattern 55 of the single color. The main scanning direction color registration deviation amount Lerr and the sub-scanning direction color registration deviation amount Perr are obtained, and the arithmetic operation of the main scanning direction color registration deviation amount Lerr and the sub-scanning direction color registration deviation amount Perr is performed. When the average is obtained, the factors based on the periodic fluctuations are canceled out, and the values of the color registration deviation amount Perr in the main scanning direction and the color registration deviation amount Perr in the sub-scanning direction obtained as a result of the arithmetic average are essentially zero. Should be.

Therefore, the value of the color registration deviation amount Lerr in the main scanning direction and the value of the color registration deviation amount Perr in the sub-scanning direction obtained as a result of the arithmetic averaging are as shown in FIG.
If it does not become zero, the value ΔV itself is detected based on the fact that the block of the monochromatic pattern 55 could not be detected due to the seam portion 25a of the intermediate transfer belt 25 or a defect 25b such as a scratch on the belt surface. It becomes an error.

Therefore, before the actual color registration misregistration detection cycle, the detection error amount measurement cycle using the single-color pattern block is provided, and the detection error amount ΔV is grasped. By calibrating the amount of deviation calculated in the actual color registration deviation detection cycle using detection error data grasped in advance, it is possible to detect a color registration deviation that does not include a detection error.

A specific description will be given. In the detection error amount measurement cycle, the color registration deviation detection error amount corresponding to the detection target color of the reference color is 7 μm in the process direction,
5 μm, the amount of color registration deviation of the color to be detected with respect to the reference color in the color registration deviation detection cycle is process-56.
If it is assumed to be μm and lateral 42 μm, calibration may be performed based on the detection error amount, and the final color registration deviation detection value may be set to process-49 μm and lateral 37 μm.

By doing so, the intermediate transfer belt 25 can be used without complicating the configuration and significantly increasing the cost.
In addition, the detection error of the detection pattern 50 due to the fluctuation of the rotation of the photosensitive drum 15 and the like can be greatly reduced, and the detection of the deviation of the color registration accompanying the sampling of the detection pattern 50 can be improved. It is possible to perform with high accuracy.

Second Embodiment FIG. 11 shows a second embodiment of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals and described. Although the detection error detection cycle is provided before the color registration deviation detection cycle, the second embodiment is configured so that the detection error using the color registration deviation detection cycle and the calibration of the detection data are simultaneously performed. Things. This relates to calibration of a detection error that occurs when the sample length is not synchronized with a long-period fluctuation.

FIG. 11 shows an arrangement in which patterns 50 used for color registration misregistration detection are partially omitted by the number of blocks to be detected. In the figure, TIA2 / T2A2 indicates the interval in the color pattern to be detected second. Here, the interval data T2B1 and T1 of the pattern 50
Pay attention to C1. These intervals T2B1 and T1C1 are:
For example, the intervals between patterns of the same color such as yellow and black are shown. That is, T2B1 is an interval formed between target colors (for example, yellow) for color registration deviation detection, and T1C1 is also an interval between reference colors (for example, black). If there is no periodic variation between the reference color and the detection target color, the difference between the measurement value and the design value of the same color should be the same value (the difference between the measurement value and the design interval value is It occurs due to the difference between the design value of the rotation speed of the photosensitive drum / belt and the actual speed.) When the difference between the measured value and the design value in the two interval data is different, the difference is caused by the periodic color registration fluctuation amount of the color registration detection target color with respect to the reference color.

The detection error is calculated from the periodic color registration fluctuation calculated from these interval data. Hereinafter, a specific example will be described.

Assume that the block length of the pattern 50 is 60 mm, the circumferential length of the intermediate transfer belt 25 is 2000 mm, the sample length is 1800 mm, and the designed value interval between T2B1 and T1C1 is 3 mm. T2B1 / T for each block
An error between a design value of the pattern interval of 1C1 and an actually measured value is calculated, and error data for the number of samples at a sample length of 1800 mm is averaged. If the error of T2B1 after averaging is 30 μm and the error of T1C1 is 25 μm, the difference of 5 μm is the detection error due to color registration fluctuation. These detection errors are calculated before calculating the actual color registration deviation amount, and the color registration deviation amount is calculated after calibrating the interval data. That is, for the data of T2B1 / T1C1 detected for each block, the detection error of the color registration deviation is subtracted by 5 μm from the actually measured data. If the color registration misregistration amount is calculated from the calibrated interval data, the color registration misregistration amount from which the detection error has been removed can be calculated.

As described above, using the normal color registration misregistration detection pattern 50, the mark interval of the reference color and the mark interval of the same detection target color are used to determine the mark interval of the reference color. By subtracting the mark interval between the same detection target colors from, the detection error of the color registration deviation of the target color can be obtained simultaneously with the normal pattern detection. Therefore, the calibration operation of the color registration deviation amount can be performed quickly, and the time required for the calibration operation and the correction operation of the entire color registration deviation amount can be reduced.

In the second embodiment, the pattern interval is described as a distance for convenience of explanation. However, the pattern interval may be performed at a time interval.

Other configurations and operations are the same as those in the first embodiment, and therefore, description thereof will be omitted.

Third Embodiment FIG. 12 shows a third embodiment of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals and described. Unlike Embodiment 1, the toner images formed by the respective image forming units on the intermediate transfer body belt are not once transferred in a multiplex manner, but are carried on a transfer material transport belt 90 as a transfer material carrier. The toner image formed by each image forming unit is directly and multiplexly transferred onto the transfer paper 34.

In the drawing, reference numerals 91 and 92 denote drive rolls and driven rolls for stretching the transfer material transport belt 90, and 93 denotes a paper transport roll for transporting the transfer paper 34 onto the transfer material transport belt 90. It is.

The other configuration and operation are the same as those of the first embodiment, and the description is omitted.

Fourth Embodiment FIG. 13 shows a fourth embodiment of the present invention. Unlike the first embodiment, the fourth embodiment differs from the first embodiment in that a photosensitive drum as an image carrier is provided on the photosensitive drum. In this configuration, toner images of different colors are sequentially formed for each rotation of the body drum, and the toner images are transferred onto the intermediate transfer member in a state of being superimposed on each other.

FIG. 13 shows a color electrophotographic copying machine as an image forming apparatus according to Embodiment 4 of the present invention. Here, the configuration of the present invention will be described using a copying machine, but the present invention is also effective in a color printer / facsimile.

In FIG. 13, reference numeral 101 denotes a main body of a color electrophotographic copying machine, and an original 102 is automatically conveyed to the upper portion of the main body 101 of the color electrophotographic copying machine in a state where the originals 102 are separated one by one. Automatic document feeder 103
And a document reading device 104 for reading an image of the document 102 conveyed by the automatic document conveying device 103. The original reading device 104 illuminates an original 102 placed on a platen glass 105 with a light source 106, and reflects a reflected light image from the original 102 from a full-rate mirror 107, half-rate mirrors 108 and 109, and an imaging lens 110. Scanning exposure is performed on an image reading element 111 such as a CCD via a reduction optical system, and the image reading element 111 converts a color material reflected light image of the original 2 at a predetermined dot density (for example, 16 dots / mm). It is designed to read.

The color material reflected light image of the original 2 read by the original reading device 4 is, for example, original reflectance data of three colors of red (R), green (G), and blue (B) (8 bits each). Is transmitted to the image processing device 112, and the image processing device 112 performs shading correction, position shift correction, lightness / color space conversion, gamma correction, frame erasure, color / movement editing on the reflectance data of the document 2. And other predetermined image processing.

The image data subjected to the predetermined image processing by the image processing device 112 as described above includes yellow (Y), magenta (M), cyan (C), and black (B
K) ROS 113 (Raster Output Scan) as original color material gradation data of four colors (each of 8 bits)
ROS 113, and the ROS 113 performs image exposure using laser light according to the original color material gradation data.

An image forming means A capable of forming a plurality of toner images of different colors is provided inside the main body 101 of the color electrophotographic copying machine. The image forming means A mainly includes a photosensitive drum 117 as an image carrier on which an electrostatic latent image is formed, and a plurality of images having different colors by developing the electrostatic latent image formed on the photosensitive drum 117. Developing device 11 as a developing means capable of forming a toner image
9.

As shown in FIG. 13, the ROS 113 modulates a semiconductor laser (not shown) according to the original reproduction color material gradation data, and emits a laser beam LB from the semiconductor laser according to the gradation data. The laser light LB emitted from the semiconductor laser is applied to a rotating polygon mirror 114.
Drum 11 serving as an image carrier through the f · θ lens 115 and the reflection mirror 116
7 is scanned and exposed.

The ROS 113 causes the laser beam LB
The photosensitive drum 117 is scanned and exposed at a predetermined speed in a direction indicated by an arrow by a driving unit (not shown). The surface of the photosensitive drum 117 is charged to a predetermined polarity (for example, a negative polarity) and a potential by a scorotron 118 for primary charging in advance, and then the laser beam LB according to the original reproduction color material gradation data.
Are scanned and exposed to form an electrostatic latent image.
The electrostatic latent image formed on the photoconductor drum 117 has four color developing units 119Y, 119M, and 119 of yellow (Y), magenta (M), cyan (C), and black (BK).
C, a rotary developing device 11 equipped with 119BK
As a result, the toner image is reversely developed with a toner (charged color material) charged to a negative polarity having the same polarity as the charged polarity of the photosensitive drum 117, thereby forming a toner image of a predetermined color. still,
The toner image formed on the photosensitive drum 117 is charged with a negative polarity by the pre-transfer charger 120 as necessary, so that the charge amount is adjusted.

The toner images of each color formed on the photosensitive drum 117 are transferred onto an intermediate transfer belt 121 as an intermediate transfer member disposed below the photosensitive drum 117.
Multiple transfer is performed by a primary transfer roll 122 as a first transfer unit. The intermediate transfer belt 121 is moved at the same moving speed as the peripheral speed of the photosensitive drum 117 by a driving roll 123, a driven roll 124 a, a tension roll 124 b, and a backup roll 125 as an opposing roll constituting a part of the secondary transfer unit. , So as to be rotatable along the arrow direction.

On the intermediate transfer belt 121, yellow (Y), magenta (M), cyan (C), and black (BK) are formed on the photosensitive drum 117 according to the color of the image to be formed. All or some of the toner images of the four colors are transferred by the primary transfer roll 122 in a state of being sequentially superimposed. The toner image transferred onto the intermediate transfer belt 121 is transferred onto a transfer sheet 126 as a recording medium conveyed to a secondary transfer position at a predetermined timing on a backup roll 125 supporting the intermediate transfer belt 121.
Then, the image is transferred by the pressing force and the electrostatic attraction force of the secondary transfer roll 127 which constitutes a part of the second transfer means that presses against the backup roll 125. Transfer paper 12
As shown in FIG. 13, reference numeral 6 denotes a predetermined size from one of a plurality of paper feed cassettes 128, 129, 130, and 131 as a plurality of recording medium accommodating members disposed in the lower portion of the color electrophotographic copying machine main body 101. Is the feed roll 12
8a, 129a, 130a, and 131a. The fed transfer paper 126 is transported by a plurality of transport rolls 1.
The intermediate transfer belt 121 is conveyed to the secondary transfer position of the intermediate transfer belt 121 at a predetermined timing by the resist roller 32 and the registration roll 133. As described above, the intermediate transfer belt 12 is transferred onto the transfer paper 126 by the backup roll 125 and the secondary transfer roll 127 as a secondary transfer unit.
1, a toner image of a predetermined color is collectively transferred from above.

The transfer paper 126 on which the toner image of a predetermined color has been transferred from the intermediate transfer belt 121 is separated from the intermediate transfer belt 121 and then transferred to the transport belt 134.
Is transported to the fixing device 135 by the fixing device 1.
The toner image is fixed on the transfer paper 126 by heat and pressure by 35, and in the case of single-sided copying, the toner image is discharged onto the discharge tray 136 as it is, and the color image copying process ends.

On the other hand, in the case of double-sided copying, the transfer paper 126 on which the color image is formed on the first surface (front surface) is not discharged onto the discharge tray 136 as it is, but is transported downward by a reversing gate (not shown). The triroll 137 and the reversing roll 13 whose directions are changed and three rolls are pressed against each other
8, the sheet is once conveyed to the reversing path 139. Then, the transfer sheet 126 is conveyed to the two-sided passage 140 by the reversing roll 138 that is reversed this time, and once conveyed to the registration roll 133 by the conveying rolls 141 provided in the two-sided passage 140 and stopped. The transfer paper 126 is conveyed again by the registration roll 133 in synchronization with the toner image on the intermediate transfer belt 121, and the transfer / fixing process of the toner image on the second surface (back surface) of the transfer paper 126 is performed. After the discharge tray 1
36.

In FIG. 13, reference numeral 142 denotes a cleaning device for removing residual toner, paper dust and the like from the surface of the photosensitive drum 117 after the completion of the transfer process, and 143, for cleaning the intermediate transfer belt 121. Reference numeral 144 denotes a manual transfer tray.

The other configuration and operation are the same as those of the first embodiment, and the description is omitted.

[0096]

As described above, according to the present invention, the detection of the detection pattern caused by the rotation fluctuation of the intermediate transfer member and the image bearing member can be performed without complicating the structure and significantly increasing the cost. A color image forming position deviation detecting apparatus and a color image forming position deviation detecting apparatus capable of detecting the deviation of the color registration accompanying the sampling of the detection pattern with high accuracy as well as the error can be greatly reduced. An image forming apparatus can be provided.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a color registration misregistration detection pattern used in a color image formation misalignment detection device according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram showing a digital color copying machine as an image forming apparatus to which the color image forming position deviation detecting apparatus according to the first embodiment of the present invention is applied.

FIG. 3 is a configuration diagram showing a digital color copying machine as an image forming apparatus to which the color image forming position deviation detecting device according to the first embodiment of the present invention is applied.

FIG. 4 is a perspective view showing an intermediate transfer belt.

FIG. 5 is an explanatory diagram showing a color registration misregistration detection pattern used in the color image forming position misalignment detection device according to the first embodiment of the present invention;

FIG. 6 is an explanatory diagram showing a color registration misregistration detection pattern used in the color image formation misalignment detection device according to the first embodiment of the present invention.

FIG. 7 is a perspective configuration diagram showing a pattern detector.

FIG. 8 is an explanatory diagram showing a detection state of a pattern detector.

FIG. 9 is a block diagram showing a color registration deviation correction circuit.

FIG. 10 is an explanatory diagram illustrating a detection state of a detection error of the color registration deviation correction circuit.

FIG. 11 is an explanatory diagram showing a color registration misregistration detection pattern used in the color image forming position misalignment detection device according to the second embodiment of the present invention.

FIG. 12 is a configuration diagram showing a digital color copying machine as an image forming apparatus to which a color image forming position deviation detecting apparatus according to Embodiment 3 of the present invention is applied.

FIG. 13 is a configuration diagram showing a digital color copying machine as an image forming apparatus to which a color image forming position deviation detecting apparatus according to Embodiment 4 of the present invention is applied.

FIG. 14 is a configuration diagram showing a digital color copying machine as an image forming apparatus to which a conventional color image forming position shift detecting apparatus is applied.

FIG. 15 is an explanatory diagram showing a color registration misregistration detection pattern used in a conventional color image formation misalignment detection device.

FIG. 16 is an explanatory diagram showing a color registration misregistration detection pattern used in a conventional color image formation misalignment detection device.

FIG. 17 is an explanatory diagram illustrating a detection state of a detection error of the color registration deviation correction circuit.

[Description of Signs] 50: Color registration misregistration detection pattern, 51KK: First
, 51YY: second mark, 51KY: third mark, 55: color registration misregistration detection pattern of the same color, 56K: mark.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 21/14 B41J 3/00 B 5B057 G06T 1/00 G03G 21/00 372 5C074 H04N 1/29 G06F 15 / 66 310 5C079 1/46 H04N 1/46 ZF term (reference) 2C061 AP03 AP04 AQ06 AR01 AS02 KK18 KK22 KK26 2C262 AA05 AA24 AA26 AA27 AB15 FA13 GA04 GA36 GA40 2F065 AA20 BB27 FF41 Q08 Q13 JJ07HH05Q08 QJHH05Q08 DE02 DE07 DE09 EB04 EC03 EC06 EC20 ED06 ED08 ED16 ED24 EE01 EE02 EE07 EF09 HA12 2H030 AA01 AB02 AD05 AD12 AD17 BB02 BB23 BB24 BB42 BB44 BB56 5B057 AA11 BA02 CA01 CA08 CA12 CB01 CB12 ACO3 CB01 A0712 EE11 FF02 FF15 GG14 HH02 HH04 5C079 HA19 HB03 KA18 LA01 LA24 MA10 NA03 NA25 NA29 PA0 1 PA02 PA03

Claims (4)

[Claims] A first mark of a first color;
A second mark of a second color, a first mark of a second color
Forming a color image formation position shift detection pattern composed of a third mark having the above-mentioned color on the surface of the detection target, and detecting the color image formation position shift detection pattern by pattern detection means. Thus, in the color image forming position shift detecting device for detecting the color image forming position shift amount, at least two marks of the color image forming position shift detecting pattern are formed in the same color and formed in the same color. The color image forming position shift detecting pattern is detected by the pattern detecting means, and the color image forming position shift detecting pattern is detected based on the interval measurement value of the color image forming position shift detecting pattern formed in the same color. A color image forming position shift detecting device for calculating an error when the color image forming process is performed. 2. A cycle for determining an error in detecting a color image forming position shift detecting pattern is provided. In this cycle, all of the color image forming position shift detecting patterns are formed in the same color, and the same color is used. The color image forming position shift detecting pattern formed by the color is detected by the pattern detecting means, and the color image forming position shift is detected based on the interval measurement value of the color image forming position shift detecting pattern formed by the same color. 2. The color image forming position deviation detecting device according to claim 1, wherein an error in detecting the detection pattern is obtained. 3. A method for detecting a color image forming position shift detection pattern based on a measured value of a space between marks formed in the same color of the color image forming position shift detection pattern when the color image forming position shift detection is performed. 2. The color image forming position deviation detecting apparatus according to claim 1, wherein an error of the color image forming position is obtained. 4. An image forming apparatus capable of forming a color image by multiplexly transferring toner images of different colors onto an intermediate transfer member or onto a transfer material carried on a transfer material carrier. A first mark composed of a first color, a second mark composed of a second color, and a first mark composed of a first color and a second color formed on the intermediate transfer member or the transfer material carrier. The third
A color image forming position shift detecting pattern formed by the second mark and the color mark forming position shift detecting pattern, and detecting the color image forming position shift detecting pattern by pattern detecting means to correct the color image forming position shift. In the image forming apparatus, at least two marks of the color image formation position shift detection pattern are formed in the same color on the intermediate transfer body or the transfer material carrier, and the color formed in the same color is formed. The pattern for detecting an image forming position shift is detected by a pattern detecting means, and the pattern for detecting a color image forming position shift is detected based on the measured interval of the color image forming position shift detecting pattern formed of the same color. An image forming apparatus, wherein an error at the time is obtained.