JP2003316102A - Image forming device and control method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make effective function of minute misregistration correction by determining whether or not the quantities of misregistration in recording at a plurality of image forming parts are beyond an allowable range. <P>SOLUTION: The device having a structure in which the image forming parts corresponding to color components for forming a color image are arranged in order is provided with sensors located downstream from the corresponding image forming parts. The device performs a recording operation for a misregistration detecting pattern which is composed of a first pattern for detecting rough misregistration and a second pattern for detecting minute registration. As a result, in the case that the rough misregistration pattern is detected and it is beyond the permissible range (S2), a signal indicating an error is input and detection of minute misregistration and correction processing are not carried out. In the case that the rough misregistration pattern is within the permissible range, a quantity of minute misregistration is detected with the second pattern and correction is carried out (S6, S8). <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color printer,
More particularly, the present invention relates to an image recording apparatus having a plurality of image forming units such as a color copying machine and a control method thereof.

[0002]

2. Description of the Related Art An electrophotographic color image forming apparatus has a plurality of image forming portions for speeding up and sequentially transfers images of different colors onto a recording material held on a conveyor belt. Have been proposed.

By the way, as a problem of the apparatus having a plurality of image forming sections, due to mechanical precision and the like, there are uneven movements of a plurality of photosensitive drums and a conveyor belt, and the outer peripheral surface of the photosensitive drum at the transfer position of each image forming section. And the amount of movement of the transport belt are different for each color, and when the images are superposed, they do not match and a color shift (positional shift) occurs. In particular, in an apparatus having a plurality of image forming units having a laser scanner and a photosensitive drum, there is an error in the distance between the laser scanner and the photosensitive drum in each image forming unit. A difference occurs in the scanning width of the laser on the drum, which causes color misregistration.

An example of color misregistration is shown in FIG. Reference numeral 7 indicates an original image position, and 8a to 8d indicate image positions when color misregistration occurs. Further, FIGS. 9A, 9B, and 9C show the case where there is a color shift in the scanning direction, but for the sake of explanation, the two lines are drawn separately in the carrying direction.

Hereinafter, the figure will be described in more detail. Figure 2
(A) shows an inclination shift of the scanning line, which occurs when there is an inclination between the optical unit and the photosensitive drum. In this case, for example, the positions of the optical unit and the photosensitive drum and the position of the lens are adjusted to make correction in the arrow direction.

FIG. 1B shows a color shift due to variations in scanning line width, which is caused by a difference in distance between the optical section and the photosensitive drum. This is likely to occur when the optical unit is a laser scanner. For example, the image frequency is finely adjusted (the frequency is increased when the scanning width is long), and the length of the scanning line is changed to correct in the arrow direction.

FIG. 1C shows a writing (exposure) position error in the scanning direction. For example, if the optical unit is a laser scanner, correction is made in the arrow direction by adjusting the writing timing from a known beam detection signal (so-called BD signal).

FIG. 3D shows the writing start position error in the paper transport direction. Correction is made in the arrow direction by adjusting the writing timing of each color from the detection of the leading edge of the paper.

In order to correct these color misregistrations, a color misregistration detection pattern is formed for each color on the conveyor belt 3 and detected by a pair of optical sensors provided on both sides of the downstream side of the conveyor belt. The various adjustments described above are performed according to the detected shift amount.

FIG. 3 shows an example of a color shift detection pattern. Here, 9x to 20x (x is a, b, c, d ...) Are patterns for detecting the amount of color misregistration in the paper transport direction and the scanning direction.

The color misregistration detection patterns 9 to 12 are pattern 1, the color misregistration detection patterns 13 to 16 are pattern 2, and the color misregistration detection patterns 17 to 20 are pattern 3.
And Further, a, c, e, and g represent K (hereinafter, K: black) that is a reference color, and b, d, and f are Y, M, and C (hereinafter, Y: yellow, M: magenta, which are detection colors), respectively. , C: cyan). taf1-7, tar
1-7, tbf1-7, tbr1-7, tcf1-7,
tcr1 to 7, tdf1 to 7, and tdr1 to 7 indicate the detection timing of each pattern, and the arrows indicate the moving direction of the conveyor belt 3. The moving speed of the conveyor belt 3 is v [mm / s], and K is a reference color.

The color shift amount δep1 of each color in the transport direction in the color shift detection pattern of pattern 1 (the letters Y, M, and C at the end of each value indicate the color components), δep1Y = v * [{ (taf2-taf1)-(taf3-taf2) + (tbf2-tbf1)-(tbf3-tbf2)} / 4 + {(tar2-tar1)-(tar3-tar2) + (tbr2-tbr1)-(tbr3-tbr2 )} / 4] / 2 Equation 1 δep1M = v * [{(taf4-taf3)-(taf5-taf4) + (tbf4-tbf3)-(tbf5-tbf4)} / 4 + {(tar4-tar3)- (tar5-tar4) + (tbr4-tbr3)-(tbr5-tbr4)} / 4] / 2… Equation 2 δep1C = v * [{(taf6-taf5)-(taf7-taf6) + (tbf6-tbf5)- (tbf7-tbf6)} / 4 + {(tar6-tar5)-(tar7-tar6) + (tbr6-tbr5)-(tbr7-tbr6)} / 4] / 2 ... Equation 3 is obtained.

Similarly, the color shift amount δep2 of each color in the transport direction in the color shift detection pattern of pattern 2 and the color shift amount δep3 of each color in the transport direction in the color shift detection pattern of pattern 3 are calculated.

Therefore, the color shift amount δep of each color in the carrying direction
Is δepY = (δep1Y + δep2Y + δep3Y) / 3 Equation 4 δepM = (δep1M + δep2M + δep3M) / 3 Equation 5 δepC = (δep1C + δep2C + δep3C) / 3 Equation 6 and the deviation direction from the positive / negative of the calculation result can be determined.

Next, a method of calculating the color shift amount in the scanning direction will be described. The color shift amounts δesf1 and δesr1 of the respective colors in the scanning direction in the color shift detection pattern of pattern 1 are δesf1Y = v * {(taf2-taf1)-(taf3-taf2)-(tbf2-tbf1) + (tbf3-tbf2 )} / 4 Equation 7 δesf1M = v * {(taf4-taf3)-(taf5-taf4)-(tbf4-tbf3) + (tbf5-tbf4)} / 4 Equation 8 δesf1C = v * {(taf6-taf5 )-(taf7-taf6)-(tbf6-tbf5) + (tbf7-tbf6)} / 4… Equation 9 δesr1Y ＝ v * {(tar2-tar1)-(tar3-tar2)-(tbr2-tbr1) + (tbr3 -tbr2)} / 4 Equation 10 δesr1M = v * {(tar4-tar3)-(tar5-tar4)-(tbr4-tbf3) + (tbr5-tbf4)} / 4 Equation 11 δesr1C = v * {(tar6 -tar5)-(tar7-tar6)-(tbr6-tbr5) + (tbr7-tbr6)} / 4 Equation 12 is obtained.

Similarly, the color shift amount δes2 of each color in the scanning direction in the color shift detection pattern of pattern 2 and the color shift amount δes3 of each color in the scanning direction in the color shift detection pattern of pattern 3 are calculated. Therefore, the amount of color shift δes of each color in the scanning direction is δesY = (δesf1Y + δesf2Y + δesf3Y + δesr1Y + δesr2Y + δesr3Y) / 6 ... Formula 14 δesC = (δesf1C + δesf2C + δesf3C + δesr1C + δesr2C + δesr3C) / 6 Formula 15 is obtained, and the deviation direction from the positive or negative of the calculation result can be determined.

Further, the color shift amount δep of each color to be the scanning width
Is δepY = (δesr1Y-δesf1Y + δesr2Y-δesf2Y + δesr3Y-δesf3Y) / 3 Formula 16 δepM = (δesr1M-δesf1M + δesr2M-δesf2M + δesr3M-δesf3Mes) 3C-17 Formula 3 -δesf2C + δesr3C-δesf3C) / 3 Equation 18 is obtained.

If there is an error in the scanning width, the writing position is calculated not only by δess, but also by taking into account the amount of change in the image frequency that has changed due to the scanning width correction.

[0019]

In the following, when the color shift detecting pattern of FIG. 3 is handled, the line width of the color shift detecting pattern is 35 dots, the length in the scanning direction of the pattern is 100 dots, and the blank portion between the patterns is present. If it is described as 50 dots, there have been the following problems so far.

When the amount of color misregistration is large due to the adjustment of the main body before assembly or the failure of parts, the conventional method causes the color misregistration detection pattern shown in FIG. 3 to overlap the reference color K and the detection colors Y, M, and C. The color shift amount cannot be detected. Further, if the allowable color shift amount is increased and the entire pattern interval is widened, downtime occurs in the color shift detection operation. Further, if the color misregistration detection pattern shown in FIG. 3 is not transferred onto the conveyor belt 3, information about which color is not transferred is not known, which may cause confusion for the user and the service person.

The present invention has been made to solve the above problems, and determines whether or not the recording position deviation amount in a plurality of image forming portions exceeds an allowable range.
(EN) An image recording apparatus and a control method thereof for effectively performing a minute positional deviation correction.

[0022]

In order to solve such a problem, for example, an image recording apparatus of the present invention has the following structure. That is, an image recording apparatus that forms an image by sequentially arranging a plurality of image forming units and superposing the images formed by the image forming units on a conveyor belt or a recording medium conveyed by the conveyor belt. For detecting the recording position shift of the image formed by the image forming unit, a detection unit provided downstream of the image forming unit for detecting the recorded image, and a detecting unit for detecting the recording position shift of each image forming unit. Generating means for generating a positional deviation detecting pattern composed of a first pattern for detecting a coarse positional deviation of a recorded image and a second pattern for detecting a minute positional deviation by each image forming unit, and the generating means. A detection unit that causes the plurality of image forming units to execute an image forming process with the generated detection pattern, and the detection unit detects the recorded image; and the detection unit, the first pattern When detecting the corresponding image, if the image of each by the plurality of image forming unit can not be detected, it is determined that there is an image forming unit which exceeds the allowable range,
The detection of the minute positional deviation amount by the second pattern is stopped, and when the images corresponding to the first pattern are detected, if the respective images by the plurality of image forming units can be detected, the second pattern is detected. And a control unit that detects a minute positional deviation amount in each image forming unit by detecting an image corresponding to the pattern.

[0023]

DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings.

<First Embodiment> FIG. 9 is a block diagram of a copying machine (color copying machine) according to the embodiment. In the figure, 101 is a CPU that controls the entire apparatus. 10
2 is an R that stores the processing procedure (program) of the CPU
This is an OM, and a color misregistration detection pattern described later is stored inside. 103 is a RAM used as a work area of the CPU 101. An operation panel 104 is composed of various switches, buttons, a liquid crystal display, and the like. Reference numeral 105 denotes an interface connected to the PC because it functions as a printer of the PC, and is a parallel or serial interface, a USB, a network interface, or the like. Reference numeral 106 denotes a reader unit for reading an original, and 107 denotes various image processing (image processing such as correction processing and trimming) on the read original image.
This is an image processing unit for performing the above, and is internally provided with an image memory for storing an image. Reference numeral 108 denotes a printer interface, which outputs a result processed by the image processing unit 107 to a printer engine 109 (this configuration will be described with reference to FIG. 1). Reference numeral 110 denotes an adjustment unit that adjusts the positions of the photosensitive drum of each color in the printer engine 109 and the position of the laser scanner unit for sweeping the laser light on the drum. This adjusting unit has a plurality of motors, and by driving each of them under the control of the CPU 101, the position in the printer engine 109 is adjusted and the color misregistration described later is corrected. Since the adjusting unit 110 itself is known,
Detailed description here is omitted.

FIG. 1 shows the main configuration of the printer engine according to this embodiment.

The present embodiment shows a color image forming apparatus having image forming portions of four colors, that is, yellow Y, magenta M, cyan C, and black K. In FIG. 1, 1 is an electrostatic latent image. Photosensitive drums (a, b, c,
d is for K, C, M, and Y), 2 is a laser scanner that forms an electrostatic latent image on the photosensitive drum 1 by performing exposure according to an image signal, and 3 is a sheet of paper for each color image forming unit. Endless conveyor belt that doubles as a transfer belt and that sequentially conveys 4
Is a drive roller which is connected to a drive means (not shown) including a motor and a gear, drives the conveyor belt 3, and 5 is a driven roller which rotates according to the movement of the conveyor belt 3 and applies a constant tension to the conveyor belt 3, 6 is provided on the downstream side of the image forming unit and the conveyor belt to detect the color misregistration detection pattern formed on the conveyor belt 3, and 1 for detecting the toner images at both side positions of the conveyor belt. It is a pair of optical sensors.

In the above structure, the document image read by the reader unit 106 is read, various image processes are performed, and a print image is generated. Also, when print data is received from a PC or the like, the print data is interpreted,
A print image is generated by the image processing unit 107. In any case, when the print image is generated, the supply of the paper is started from the paper cassette (not shown), and the image formation is started at the timing of each color component. That is, the image signal of each color is sent to each laser scanner 2,
An electrostatic latent image is formed on the photosensitive drum 1, and the toner image is transferred onto the conveyor belt 3. The toner formed on the conveyor belt 3 is transferred onto the conveyed recording paper via a transfer roller (not shown) in contact with the conveyor belt 3 and finally fixed by a heat fixing device, and then externally. Is discharged to.

Now, in the above configuration, when the power of the apparatus is turned on or when a color misregistration adjustment process is instructed on the operation panel 104, the CPU 101 causes the ROM 10 to operate.
Based on the color shift detection pattern data stored in 2,
The image processing unit 107 is caused to generate a print image, the result is output to the printer engine 109, and the sensor 6a in FIG.
The signal from 6b is received via the printer interface, and the color shift amount in the image forming unit for each color is calculated. Then, based on the calculated result, the adjusting unit 110 is controlled to correct the color misregistration.

The principle of color misregistration detection will be described below. Such a configuration is composed of the sensors 6a and 6b, the CPU 101, and various processing units, and a conceptual diagram thereof is shown in FIG. become. The configuration shown in the figure is called a pattern reading processing unit.

The pattern reading processing section includes a sensor 6a,
A pattern detection unit 22 (including two) including an LED light emitting unit of 6b, a photo sensor light receiving unit, and the like, an A / D unit 23 that digitizes an analog signal from the sensor, and digital data is arithmetically processed to obtain a color shift amount. And a calculation unit 24 that calculates a correction value, an image output unit 25 that forms an image according to the calculation result, and timing adjustment and various settings of each unit,
It is composed of a timer 21 and a CPU 101. Hereinafter, the processing of the figure will be described.

A color misregistration detection pattern as shown in FIG. 5 is formed on the conveyor belt 3 and read by a pair of sensors 6a and 6b provided on both sides of the conveyor belt, and the center value of the color misregistration detection pattern is read. To detect.

In FIG. 5, 27 to 34 are horizontal line patterns (width: 50 dots) for coarse adjustment, 27 and 28 are Y, 29 and 30 are M, 31 and 32 are C, 33 and 34 are K.
Each ingredient is shown. Further, 35 to 46 are fine adjustment patterns, which are color shift detection patterns of FIG. In the rough adjustment pattern, if the theoretical distance between each color and the K pattern is dpYmm, dpMmm, and dpCmm, the transfer direction color shift amount δEP of the rough adjustment pattern.
Is δEPY = dpY-v * {(tgf4-tgf1) + (tgr4-tgr1)} / 2 Equation 19 δEPM = dpM-v * {(tgf4-tgf2) + (tgr4-tgr2)} / 2 Equation 20 ΔEPC = dpC-v * {(tgf4-tgf3) + (tgr4-tgr3)} / 2 Equation 21 is obtained.

Here, it is assumed that the amount of color misregistration in the transport direction of each color that occurs before adjustment during assembly of the main body is smaller than 100 dots, and the center of the coarse adjustment pattern is set to Y from the image writing position.
(27,28): 100dot, M (29,30): 2
50 dot, C (31, 32): 400 dot, K (3
3, 34): 550dot is the theoretical distance.

Next, the procedure of color misregistration correction processing will be described. The color misregistration correction process is performed according to the procedure shown in FIG.

First, an image forming process using the color shift correction pattern is executed (step S1). As a result, the toner of the color misregistration detection pattern is formed on the conveyor belt 3 and is conveyed, so that it can be detected by the sensors 6a and 6b.

Then, it is determined whether the coarse adjustment pattern is within the allowable range (step S2). Specifically, since it is assumed that the amount of color misregistration in the transport direction of each color that occurs is smaller than 100 dots, the coarse adjustment pattern for each color is within ± of the theoretical distance.
It may be determined that it is within 50 dots. Therefore, the center value of the coarse adjustment pattern for each color is Y from the image writing position.
(27, 28): +50 dot to +150 dot, M
(29, 30): + 200dot to + 300dot, C
(31, 32): +350 dot to +450 dot, K
(33, 34): It may be determined whether it is within the range of +500 dots to +600 dots.

If even one color of the rough adjustment pattern is out of the above range, it is considered that the color misregistration detection pattern has not been transferred onto the conveyor belt 3 and the color outside the range is regarded as an error color. The image having the message set as is printed by using the color determined to be within the normal range (step S3), and the user and the service person can be notified of the error content and the error color.

On the other hand, if all the color misregistration detection patterns are within the above range, it is next determined whether or not the fine adjustment pattern can be detected (step S4). This determination method may be performed by detecting the number of fine adjustment patterns detected.
Here, when the amount of color misregistration is large and the patterns for color misregistration detection overlap and the number of detected lines is less than the number of patterns for color misregistration detection, the amounts of color misregistration in the transport direction of the rough adjustment patterns are given by the expressions 19 to 21. Is calculated (step S5). Then, based on the detected color misregistration amount in the transport direction, the adjusting unit 11
0 is controlled and corrected, and the color misregistration correction process is executed again (step S6). The adjustment is performed not only by the adjustment unit 110, but also by adjusting the output timing of each color component generated by the image processing unit 107 and the clock at that time, as necessary.

On the other hand, if it is determined that the fine adjustment pattern can be detected, the color misregistration amounts of the fine adjustment pattern in the carrying direction and the scanning direction are calculated by the formulas 1 to 18 (step S).
7). Then, the detected color misregistration amounts in the transport direction and the scanning direction are corrected (step S8), and the color misregistration correction system ends.

Here, the color component Y (yellow) is not transferred onto the conveyor belt due to a component failure or the like, and M,
When C and K are not displaced in the transport direction compared with the theoretical distance from the image writing position, the conventional method cannot detect the color misregistration detection pattern. Furthermore, because the error color that failed to be detected (the color shift amount is large) cannot be determined,
This may lead to confusion among users and service personnel. However, when this method is adopted, it is possible to determine the error color (Y) that has failed to be detected (the color shift amount is large) in the rough adjustment pattern, and thus the error color (Y) can be avoided without causing confusion for the user and the service person. Can inform you.

Further, the color misregistration amount in the Y-K transport direction is + 50d.
If there is no color misregistration amount in the transport direction of ot, MK, and CK,
The conventional method cannot detect the color shift detection pattern. Furthermore, since the error color that has failed to be detected (the amount of color misregistration is large) cannot be determined, there is a risk of confusion between the user and the service person. However, if this method is adopted,
The amount of color misregistration in the transport direction is detected and corrected using the coarse adjustment pattern. After that, the color shift detection pattern is formed again, and the color shift amounts of the fine adjustment pattern in the carrying direction and the scanning direction are detected and corrected. Therefore, using the color shift detection pattern of FIG. 5,
When this method is adopted, the color shift amount can be detected and corrected even when the color shift amount in the transport direction is large.

<Second Embodiment> A second embodiment will be described. The publicly known device in the second embodiment is the same as that in the first embodiment (FIGS. 1 and 9). The color shift detection pattern is shown in FIG. 47 to 54 are horizontal line patterns (width: 50 dots) for coarse adjustment, 55 to 6
2 is a diagonal pattern (width: 50 dots) for rough adjustment, 47, 48, 55, 56 are Y, 49, 50, 57,
58 is M, 51, 52, 59, 60 is C, 53, 54,
Reference numerals 61 and 62 denote K color components. Also 63-7
Reference numeral 4 denotes a fine adjustment pattern, which is the color shift detection pattern of FIG. In the rough adjustment pattern, the transport direction color shift amount δEP is expressed by Expressions 19 to 21. The color shift amount δES in the scanning direction is δESY = v * {(tof4-tnf4)-(tof1-tnf1) + (tor4-tnr4)-(tor1-tnr1)} / 4 Equation 22 δESM = v * {(tof4 -tnf4)-(tof2-tnf2) + (tor4-tnr4)-(tor2-tnr2)} / 4 Equation 23 δESC = v * {(tof4-tnf4)-(tof3-tnf3) + (tor4-tnr4)- (tor3-tnr3)} / 4 Equation 24 is obtained.

Here, it is assumed that the amount of color misregistration in the transport direction and the scanning direction of each color that occurs before adjustment during assembly of the main body is smaller than 100 dots, and the center of the coarse adjustment pattern is set to Y (47, 48) from the image writing position: 100 dot, M (49, 5
0): 250dot, C (51,52): 400do
t, K (53, 54): 550 dot, Y (55, 5)
6): 800 dots, M (57, 58): 1050 do
t, C (59, 60): 1300 dot, K (61, 6)
2): The theoretical distance is 1550 dots.

Next, the color misregistration correction process shown in FIG. 6 will be described.

First, an image is formed by the color misregistration correction pattern (step S1). Then, it is determined whether the coarse adjustment pattern (horizontal line pattern) is within the allowable range (step S2). Specifically, since it is assumed that the color shift amount of each color in the transport direction and the scanning direction is smaller than 100 dot, the coarse adjustment pattern (horizontal line pattern) of each color is ±± from the theoretical distance.
It may be determined that it is within 50 dots. Therefore, the center value of the coarse adjustment pattern for each color is Y from the image writing position.
(47, 48): +50 dot to +150 dot, M
(49, 50): + 200dot to + 300dot, C
(51, 52): +350 dot to +450 dot, K
(53, 54): It may be determined whether it is within the range of +500 dots to +600 dots. Here, if even one color of the rough adjustment pattern is out of the above range, it is considered that the color misregistration detection pattern has not been transferred onto the conveyor belt 3, and the out-of-range color color is displayed as a message image regarding the error color. To
It is formed using the color components in the normal range (step S3), and the error content and the error color are notified to the user and the service person.

On the other hand, if all the color misregistration detection patterns are within the above range, it is determined whether the fine adjustment pattern can be detected (step S4). This determination method may be performed by detecting the number of fine adjustment patterns detected. If the amount of color misregistration is large and the patterns for color misregistration detection overlap, and the number of detected lines is less than the number of color misregistration detection patterns, the amount of color misregistration in the transport direction of the rough adjustment pattern is scanned by equations 19 to 21. The color misregistration amount in the direction is calculated by the expressions 22 to 24 (step S5). Then, adjustment is performed based on the detected color misregistration amounts in the transport direction and the scanning direction (step S
6) Then, the color misregistration correction process is executed again.

On the other hand, if it is determined that the fine adjustment pattern can be detected, the color shift amounts of the fine adjustment pattern in the carrying direction and the scanning direction are calculated by the equations 1 to 18 (step S).
7). Then, an adjustment process is performed based on the detected color misregistration amounts in the transport direction and the scanning direction (step S8), and this process ends.

If there is no color misregistration amount in the Y-K transport direction and the scanning direction +50 dot, and in the M-K and C-K transport directions and the scanning direction, the conventional method is for detecting the color misregistration. The pattern could not be detected. Furthermore, since the error color that has failed to be detected (the amount of color misregistration is large) cannot be determined, there is a risk of confusion between the user and the service person. However, when this method is adopted, the amount of color misregistration in the carrying direction and the scanning direction is detected and corrected by the rough adjustment pattern. After that, the color shift detection pattern is formed again, and the color shift amounts of the fine adjustment pattern in the carrying direction and the scanning direction are detected and corrected. Therefore, if this method is adopted using the color shift detection pattern of FIG. 5, the color shift amount can be detected and corrected even when the color shift amount in the carrying direction and the scanning direction is large.

<Third Embodiment> The color misregistration detection pattern for coarse adjustment in the third embodiment is that shown in FIG. 8 (the fine adjustment pattern is the same as in the first and second embodiments). ). The device configuration is similar to that of the first and second embodiments, and the description thereof is omitted.

In FIG. 8, 75 and 76 are patterns for rough adjustment. a and h are Y, b and c are M, d and e are C, f and g are K, and a, b and c, d and e,
The patterns of f, g, and h overlap. The pattern width δEW of a, b and c, d and e, f and g, h is δEWYM = v * {(tvf2-tvf1) + (tvr2-tvr1)} / 2 Equation 25 δEWCK = v * {(tvf4- tvf3) + (tvr4-tvr3)} / 2 ... Equation 26 δEWKY = v * {(tvf6-tvf5) + (tvr6-tvr5)} / 2 ... Equation 27 δEWYM = v * {(tvf8-tvf7) + (tvr8- tvr7)} / 2 ... Equation 28 is obtained.

Here, it is assumed that the amount of color misregistration in the carrying direction of each color that occurs before adjustment during assembly of the main body is smaller than 50 dots, the width of each pattern is 105 dots, and the pattern width where two different colors overlap is 50 dots. .

Next, the problem of whether the coarse adjustment pattern in the color misregistration correction process shown in FIG. 6 is within the allowable range will be described.

First, the image forming process of the color misregistration correction pattern is executed. Then, it is determined whether the pattern width of the rough adjustment pattern is within the allowable range. Specifically, since it is assumed that the color misregistration amount of each color in the carrying direction is smaller than 50 dots, the pattern width of the coarse adjustment pattern is +110 to +160 dots.
It may be determined that it is within the range. Therefore, the pattern width of the rough adjustment pattern is YM (a, b): +110 to +
160 dot, MC (c, d): +110 to + 160d
ot, CK (e, f): +110 to +160 dot, K
Y (g, h): It is determined whether it is within the range of +110 to +160 dots. Here, in the rough adjustment pattern, YM (a,
If b) and KY (g, h) are out of the above range, it is considered that the color misregistration detection pattern has not been transferred onto the conveyor belt 3, and the out-of-range color color (Y) is set as an error color. However, the user and the service person can be notified of the error content and the error color. Similarly, YM (a, b) and MC
If (c, d) is out of the range, the color color not transferred in the color misregistration detection pattern is M, and MC (c,
If d) and CK (e, f) are out of the range, the color color not transferred in the color misregistration detection pattern is C,
If CK (e, f) and KY (g, h) are out of the range, the color color not transferred in the color misregistration detection pattern is K.

Here, when Y is not transferred onto the conveyor belt due to a component failure or the like, and M, C, and K are not displaced in the conveying direction compared with the theoretical distance from the image writing position, The method could not detect the color shift detection pattern. Further detection failed (large amount of color shift)
Since the error color cannot be determined, there is a risk of confusion between the user and the service person. However, when this method is adopted, the pattern width for rough adjustment is YM (a, b): 105d.
ot, MC (c, d): 160 dot, CK (e,
f): 160 dots, KY (g, h): 105 dots. From this result, it is possible to determine the error color (Y) that has failed to be detected (the color shift amount is large) in the rough adjustment pattern, and thus the user and the service person are not confused.
The error color (Y) can be notified.

As described above, the first, second, third
According to the embodiment, the color misregistration detection pattern has a coarse adjustment pattern and a fine adjustment pattern including the patterns of the respective color colors, and is transferred onto the endless belt by the detection signal of the coarse adjustment pattern. It is possible to discriminate an error color such as discrimination of a color color that is not present.

Further, as in the first and second embodiments, by using only the horizontal line pattern as the coarse adjustment pattern,
The amount of color misregistration can be detected in a short time. By using only the diagonal pattern for the fine adjustment pattern, it is possible to accurately detect the color shift amount.

The color misregistration detection patterns shown in the embodiments are not limited to those shown in FIGS. 5, 7 and 8 and may be changed as appropriate.

In the embodiment, the color copying machine has been described as an example, but it may be a printer or may be a printer having a plurality of image forming portions, so that it is not necessarily a color printer.

Further, in the embodiment, the printer engine in which the toner images of respective colors are formed on the endless belt and the toner on the belt is transferred to the recording paper has been described as an example, but not on each belt, but on the recording paper. Alternatively, the toner on the photosensitive drum may be directly transferred. In this case, the sensor 6a,
6b only detects the image on the recording paper.

[0060]

As described above, according to the present invention, it is possible to effectively operate the minute positional deviation correction by determining whether the recording positional deviation amount in the plurality of image forming portions exceeds the allowable range. It will be possible.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a main configuration of a printer engine according to an embodiment.

FIG. 2 is a diagram showing a state of recording position deviation.

FIG. 3 is a diagram showing a color shift detection pattern.

FIG. 4 is a configuration diagram of a positional deviation detection processing unit in the embodiment.

FIG. 5 is a diagram showing a color shift detection pattern in the embodiment.

FIG. 6 is a flowchart illustrating a processing procedure of color misregistration correction processing according to the embodiment.

FIG. 7 is a diagram showing a pattern for detecting color misregistration in the second embodiment.

FIG. 8 is a diagram showing a coarse color shift detection pattern in the third embodiment.

FIG. 9 is a block configuration diagram of an apparatus to which an embodiment is applied.

Claims (5)

[Claims] 1. An image recording apparatus for forming an image by arranging a plurality of image forming units in order and superposing the images formed by the image forming units on a conveyor belt or a recording medium conveyed by the conveyor belt, In order to detect the recording position shift of the image formed by each image forming unit, a detection unit provided downstream of the image forming unit for detecting the recorded image and a recording position shift of each image forming unit are detected. Therefore, generating means for generating a positional deviation detection pattern composed of a first pattern for detecting a coarse positional deviation of a recorded image by each image forming unit and a second pattern for detecting a minute positional deviation, A detection unit that causes the plurality of image forming units to execute an image forming process using the detection pattern generated by the generation unit, and that detects the recorded image by the detection unit; and the detection unit that detects the first pattern. When the images corresponding to the image are detected, if the respective images by the plurality of image forming units cannot be detected, it is determined that there is an image forming unit that exceeds the allowable range, and the minute positional deviation amount due to the second pattern is detected. When detection of the image corresponding to the first pattern is stopped when detection of each image by the plurality of image forming units is possible, the image corresponding to the second pattern is detected. An image recording apparatus comprising: a control unit that detects a minute positional deviation amount in each image forming unit. 2. The image recording apparatus according to claim 1, wherein the plurality of image forming units form an image of each color component of a color image. 3. The image recording device according to claim 1, wherein the detection unit includes a plurality of sensors that detect images at different positions orthogonal to the conveyance direction of the conveyance belt. apparatus. 4. The first pattern is a straight line pattern orthogonal to the carrying direction, and the second pattern is a straight line pattern oblique to the carrying direction, and the direction is different depending on the position of each sensor. The image recording apparatus according to claim 3, wherein 5. A method for controlling an image recording apparatus, wherein a plurality of image forming units are arranged in order and an image is formed by superposing the images formed by the image forming units on a conveyor belt or a recording medium conveyed by the conveyor belt. Therefore, in order to detect the recording position deviation of each image forming unit, it is composed of a first pattern for detecting a coarse position deviation of a recorded image by each image forming unit and a second pattern for detecting a minute position deviation. And a detection pattern generated in the generating step, the image forming process is executed in the plurality of image forming sections, and the image forming process is performed on the downstream side of the plurality of image forming sections. A detecting step of detecting a recorded image by using a predetermined detecting means for detecting an image to be recorded, and the detecting step detects an image corresponding to the first pattern, When the respective image formation units cannot detect the respective image formation units, it is determined that there is an image formation unit that exceeds the allowable range, the detection of the minute positional deviation amount by the second pattern is stopped, and the image corresponding to the first pattern is detected. When each image can be detected by the plurality of image forming units when detecting, the minute positional deviation amount in each image forming unit is detected by detecting the image corresponding to the second pattern. A method for controlling an image recording apparatus, comprising: a control step.