JPH1010830A - Image forming device, electronic equipment, image forming method and storage medium storing program code capable of being read out by computer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transfer the images of different colors on an image carrier without causing positional deviation and to continuously form a high-quality color image without receiving the effect of secular change or the like by controlling the respective generation timing of plural image signals based on the respective positions of the plural position detecting images. SOLUTION: An image tip sensor is actuated in response to a generated prescribed reference signal. Then, the plural images 13a-13d of the different colors formed on a photoreceptive drum 12 by an image forming means are read and the positions thereof are detected by a sensor 11. Based on the detected positions, the positional deviation of the images of the respective colors formed by the image forming means is calculated by a CPU 60. Then, the generation timing of the reference signal is corrected based on the calculated positional deviation and transferred to a controller part. Besides, the image forming timing of the image forming means which should form the images of the respective colors in a sub-scanning direction is corrected. Thus, the transfer positions of the images of the respective colors in the sub-scanning direction are corrected and the color image without color slippage is formed.

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, an electronic apparatus, an image forming method, and a computer capable of forming a color image by transferring an image obtained by superimposing and transferring a developer of different colors on an image carrier to a recording medium. Relates to a storage medium storing a readable program code.

[0002]

2. Description of the Related Art FIG. 10 is a schematic sectional view illustrating the structure of an image forming apparatus of this type, and is a schematic sectional view of a color laser beam printer in which electrophotographic technology is applied to a printer. Hereinafter, the configuration and operation will be described.

An image signal sent from an external host computer 1000 is sent to a controller unit 14 of a printer, converted into a printable signal, and sent to a laser driver 61 via a CPU 60. Then, the light emission intensity of the laser light is modulated, the optical path is adjusted by the folding mirror 62, and an electrostatic latent image is formed on the photosensitive drum 12. The portion of the electrostatic latent image on the photosensitive drum 12 irradiated with the laser beam is
The image is selectively visualized by an electric field formed by the voltage applied to the developing sleeves of the developing units 64a to 64d and the surface potential of the photosensitive drum 12. The image density is substantially determined by the electric field strength, the characteristics of the toner, and the amount of toner on the developing sleeve. 63 is a charger for uniformly charging the photosensitive drum 12.

The image visualized on the photosensitive drum 12 is temporarily transferred to an intermediate transfer belt (hereinafter, referred to as a primary transfer roller 75) by a primary transfer roller 75.
An inverted image is formed on the ITB 73, and this operation is performed in yellow (hereinafter abbreviated as Y), magenta (hereinafter abbreviated as M), cyan (hereinafter abbreviated as C), and black (hereinafter abbreviated as C).
Bk) to form an inverted full-color image on the ITB 73. The transfer belt 73 is driven by rollers 74 to 76, 78.

The transfer material in the storage cassette 65 is taken out one by one by a paper feed roller 66,
7, the write timing is adjusted. Then, the toner image on the ITB 73 is transferred to the transfer material by the secondary transfer roller 77. After that, the image is made into a permanent fixed image by the fixing roller 69 and the pressure roller 70 via the transport belt 68, and is stacked on the tray 71. Here, the controller 14 separates the image signal into process colors (usually Y, M, C, and Bk) owned by the printer, and sends a drawing signal to the laser driver 61 with each toner. The color reproduction range is determined by the density of each toner and the method of superimposing them. Further, in order to control the displacement between the colors, the fixing strength between the photosensitive drum 12 and the ITB 73 is increased, and a flywheel (not shown) is attached to the photosensitive drum 12 to prevent adverse effects such as skipping of the drive gear. An approach has been attempted.

Here, as a method of controlling the density of each color toner, a light emitting element such as an LED and a photodiode (C
An optical sensor 11 composed of a light receiving element such as dS) is provided to measure the density of the toner transferred onto the photosensitive drum 12, transfer the value to the controller unit 14 to control the developing bias, and adjust the density due to factors such as environmental changes. To reduce the variation.
In some cases, the optical sensor 11 for controlling the density is installed on the ITB 73 to control the density.

[0007]

However, in the image forming apparatus having the conventional configuration, in order to reduce the color shift,
By taking measures such as adopting a flywheel and increasing the accuracy of individual parts, there have been problems such as an increase in cost and a decrease in throughput due to enhancement of rigidity. In addition, even those having a good level in the initial state of use have a problem that color shift is deteriorated due to environmental changes, durability, and the like.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to detect the amount of misregistration of a different color patch image formed on an image carrier and to detect the amount of misregistration of each color image. An image forming apparatus and an electronic apparatus capable of transferring a different-color image onto an image carrier without positional deviation and continuously forming a high-quality color image without being affected by aging or the like by correcting the formation timing Another object of the present invention is to provide an image forming method and a storage medium storing a computer readable program code.

[0009]

According to a first aspect of the present invention, a surface image is formed each time the image carrier makes one rotation based on a plurality of color image signals generated by a predetermined generating means. An image forming apparatus that forms a plurality of position detection images by performing a plurality of image forming operations on the image carrier in an image forming apparatus that forms a color image on the image carrier; Detecting means for detecting the position of each of the plurality of position detection images, and outputting a control signal for controlling the generation timing of each of the plurality of image signals by the predetermined generating means based on the position detected by the detecting means And output means for performing the operation.

According to a second aspect of the present invention, there is provided an image forming apparatus which forms a color image by superimposing on an image carrier based on a plurality of color image signals generated by an external generating means. Forming means for forming a plurality of position detection images by performing a plurality of image forming operations thereon; detecting means for detecting each position of the plurality of position detection images formed by the forming means; And output means for outputting information based on the position detected by the control means to the external generating means.

A third invention according to the present invention further comprises control means for controlling the generation timing of each of the plurality of color image signals by the predetermined generation means based on the control signal.

According to a fourth aspect of the present invention, the forming means forms the position detection image using a plurality of colors used for forming the color image.

According to a fifth aspect of the present invention, the forming means forms the position detection image using a smaller number of colors than a plurality of colors used for forming the color image.

According to a sixth aspect of the present invention, each position is detected by the detecting means by a single detecting means.

In a seventh aspect according to the present invention, each position by the detecting means is performed by a plurality of detecting means.

According to an eighth aspect of the present invention, a plane image is superimposed on the image carrier every time the image carrier makes one rotation based on image signals of a plurality of colors generated by predetermined generating means. In an image forming apparatus for forming an image, a first forming unit for forming a plurality of position detection images by performing a plurality of surface image forming operations on an image carrier, and a single surface on the image carrier. A second forming unit that forms a plurality of position detection images different from the plurality of position detection images formed by the first forming unit by performing an image forming operation;
Detecting means for detecting the positions of the plurality of position detection images formed by the forming means, and the plurality of position detection images formed by the second forming means, based on the positions detected by the detecting means. Output means for outputting a control signal for controlling the generation timing of each of the plurality of color image signals by the predetermined generation means.

According to a ninth aspect of the present invention, there is provided an image forming means for forming an image on an image carrier, and a plurality of developing means for developing the image formed by the image forming means with developers of different colors. A synchronization generating means for generating a synchronization signal in the main scanning direction with respect to the image carrier, operating in response to the synchronization signal, and reading a plurality of different color patch images formed on the image carrier by the image forming means. A plurality of detecting means for detecting an effective patch image area in a main scanning direction orthogonal to the moving direction of the image carrier; and a main scanning direction of each color image formed by the image forming means based on an output of each detecting means. Calculating means for calculating the amount of positional deviation; and main scanning direction of the image forming means for forming each color image after detecting the synchronization signal based on the amount of positional deviation in the main scanning direction calculated by the calculating means. In which a control means for correcting the image formation timing.

According to a tenth aspect of the present invention, there is provided an electronic apparatus for generating a plurality of surface image signals and outputting the image signals to an external image forming apparatus, wherein the external image forming apparatus includes a predetermined image carrier. A receiving unit that receives information based on a relative positional shift amount of each surface image forming operation when performing a plurality of surface image forming operations, and the plurality of surface images based on information received by the receiving unit. Control means for controlling the output timing of outputting each of the signals to the external image forming apparatus.

According to an eleventh aspect of the present invention, the electronic device is a computer that outputs a color image signal to the image forming apparatus.

According to a twelfth aspect of the present invention, there is provided an electronic apparatus for generating a plurality of plane image signals and outputting the plane image signals to an external image forming apparatus, wherein the external image forming apparatus has a predetermined image carrying signal. Receiving means for receiving information based on the relative positional deviation amount of each surface image formation when performing a plurality of surface image forming operations on the body, and display means for displaying according to the information received by the receiving means And

According to a thirteenth aspect of the present invention, a plane image is superimposed on the image carrier every time the image carrier makes one rotation based on image signals of a plurality of colors generated by predetermined generating means, In an image forming method for forming an image, a forming step of forming a plurality of position detection images by performing a plurality of image forming operations on the image carrier, and a position of each of the formed plurality of position detection images And an output step of outputting a control signal for controlling the generation timing of each of the plurality of image signals by the predetermined generation unit based on the detected position.

According to a fourteenth aspect of the present invention, there is provided an image forming method for forming a color image by superimposing on an image carrier based on a plurality of color image signals generated by an external generating means. By performing a plurality of image forming operations thereon, a forming step of forming a plurality of position detection images, a detection step of detecting each position of the formed plurality of position detection images, An output step of outputting information based on the information to the external generating means.

According to a fifteenth aspect of the present invention, a plane image is superimposed on the image carrier every time the image carrier makes one rotation based on image signals of a plurality of colors generated by predetermined generating means. In an image forming method for forming an image, a first forming step of forming a plurality of position detection images by performing a plurality of surface image forming operations on an image carrier; By performing the image forming operation, a second forming step of forming a plurality of position detection images different from the plurality of position detection images formed by the first forming means, and a plurality of position detection images formed by the first forming step A plurality of position detection images,
A detecting step of detecting positions of the plurality of position detection images formed in the second forming step, and respective generation timings of image signals of a plurality of colors by the predetermined generating unit based on the detected positions An output step of outputting a control signal for controlling

According to a sixteenth aspect of the present invention, a plane image is superimposed on the image carrier every time the image carrier makes one revolution based on image signals of a plurality of colors generated by predetermined generating means. In a storage medium storing a computer-readable program code for forming an image, a plurality of image forming operations are performed on the image carrier, thereby forming a plurality of position detection images. Based on the program code of the detecting step of detecting each position of the formed plurality of position detection images and the detected position, the generation timing of each of the plurality of image signals by the predetermined generation unit is controlled. A computer-readable program code including a program code of an output step of outputting a control signal is stored in a storage medium.

According to a seventeenth aspect of the present invention, a computer that performs image forming processing for forming a color image by superimposing on an image carrier based on a plurality of color image signals generated by an external generating means is readable. In the storage medium storing the program code, by performing a plurality of image forming operations on the image carrier, a program code of a forming step of forming a plurality of position detection images, and a program code of the formed plurality of position detection images A computer-readable program code including a program code of a detection step of detecting each position and a program code of an output step of outputting information based on the detected position to the external generating means, Is stored in.

According to an eighteenth aspect of the present invention, a surface image is superimposed on the image carrier every time the image carrier makes one rotation based on a plurality of color image signals generated by predetermined generating means, A program for a first forming step of forming a plurality of position detection images by performing a plurality of surface image forming operations on an image carrier in a storage medium storing a computer-readable program code for forming an image A second surface forming operation that forms a plurality of position detection images different from the plurality of position detection images formed by the first forming unit by performing a single surface image forming operation on the code and the image carrier;
And a program for a detecting step for detecting the positions of the plurality of position detection images formed in the first forming step and the plurality of position detection images formed in the second forming step A computer-readable program including a code and a program code of an output step of outputting a control signal for controlling generation timing of each of a plurality of color image signals by the predetermined generation unit based on the detected position. The code is stored in a storage medium.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION

[First Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a view for explaining a main configuration of an image forming apparatus according to a first embodiment of the present invention. The same components as those in FIG. 10 are denoted by the same reference numerals.

In the embodiment of the present invention, the screen image means each transfer image when an image formed on the photosensitive member is superimposed a plurality of times for each rotation of the transfer member.

In FIG. 1, reference numeral 11 denotes an optical sensor (sensor) including a light emitting element such as an LED and a light receiving element such as a photodiode CdS, 12 denotes photosensitive drums, 13a, 13b,
13c and 13d are patches of each color toner transferred on the photosensitive drum 12 (for example, magenta, cyan, yellow, and black), 60 is a one-chip microcomputer (hereinafter, referred to as CPU) with a built-in ROM, and t ₁ and t. ₂ ,
t ₃ and t ₄ represent the time from when the photosensitive drum 12 is stopped to when patches 13a, 13b, 13c and 13d are detected, respectively.

Patches 13a, 13b, 13c, 1 of each color
3d is formed so as to be continuous with the rotation direction A of the photosensitive drum 12, and the sensor 11 optically measures the density of the photosensitive drum 12 from the reflectance. At this time, the photosensitive drum 12 is rotating at a constant speed at a predetermined speed.
It is stored in the ROM in U60, and is formed on the photosensitive drum 12 without being shifted on the signal.

The sensor 11 in the present embodiment performs density detection, which is a known means, and
From the stopped state, the respective color patches 13a, 13b, 13
Times t ₁ , t ₂ , t ₃ , t until detection of c and 13d
Count _four .

Hereinafter, this embodiment will be described with reference to FIG.

In the first embodiment, an image forming means (laser scanning unit) for forming an image on an image carrier (photosensitive drum 12) and a developer of a different color for forming an image by the image forming means are used. A plurality of developing means (developing units 64a to 64d), a generating means (image leading end sensor not shown) for generating a predetermined reference signal in accordance with the rotational driving of the image carrier, A detecting means (sensor 11) which operates, reads a plurality of different color patch images formed on the image carrier by the image forming means, and detects respective positions thereof, and the image forming means based on an output of the detecting means First calculating means (CPU 60) for calculating the amount of displacement of each color image formed by
A first control for correcting the image forming timing in the sub-scanning direction of the image forming unit to form each color image after detecting the predetermined reference signal based on the positional shift amount calculated by the first calculating unit; Means (the CPU 60 controls the laser driver 61 by executing a control program stored in a ROM or the like), and operates in accordance with a predetermined reference signal (TOP signal) generated by the image leading edge sensor to perform the image formation. When the sensor 11 reads a plurality of different-color patch images formed on the photosensitive drum 12 by the means and detects their positions, the CPU 60 calculates the positional deviation amount of each color image formed by the image forming means based on the detected positions. And
The generation timing of the TOP signal is corrected based on the calculated positional shift amount and transferred to the controller unit 14, and the image forming timing in the sub-scanning direction of the image forming unit for forming each color image is corrected. By correcting the transfer position in the sub-scanning direction, a color image without color shift can be formed.

In the first embodiment, the image forming means forms each of the different-color patch images so as to be continuous along the moving direction of the image carrier (see FIG. 1). The means (sensor 11) can detect the transfer position deviation of each color image in the sub-scanning direction.

FIG. 2 is a characteristic diagram showing a change in density patch detection by the sensor 11 shown in FIG. 1. The vertical axis indicates density, and the horizontal axis indicates time.

In the figure, t _M , t _C , t _Y , and t _K indicate logical detection times. Here, t _M −t ₁ , t _C −t
₂ , t _Y −t ₃ and t _K −t ₄ are deviation amounts of the respective colors with respect to the logical values, and the respective correlations are recognized by the CPU 60 as the color deviation amounts, and the recognized color deviation amounts are determined by the command / status. To the controller unit 14 by
Command / status transmission / reception uses serial communication as shown in FIG.

FIG. 3 is a timing chart for explaining a communication process between the CPU 60 and the controller unit 14 shown in FIG.

The controller 14 sends a command to the CPU 6
0, and when the status is received from the CPU 60, the command BUSY signal line (/ CBSY signal line) is set to O.
N, and a 1-byte (8-bit) command
The 8th bit up to the 8th bit from the st bit is put on the status / command signal line (/ SC signal line), transmitted by eight synchronization pulses from the serial clock signal line (/ SCLK signal line), and then the / CBSY signal line is sent. Turn off.

Thereafter, the CPU 60 sets the status BUSY
The signal line (/ SBSY signal line) is turned on, and during this time, the status of 1 byte is transferred from the 1st bit to the 8th bit on the / SC signal line, and 8 bytes from the / SCLK signal line
The signal is transmitted by the generated synchronization pulse, and thereafter the / SBSY signal line is turned off.

The / CBSY signal line and / SBS described above
The Y signal line, the / SC signal line, and the / SCLK signal line connect the controller unit 14 and the CPU 60 via a video I / F.

FIGS. 4 and 5 show examples of commands / status between the CPU 60 and the controller unit 14 shown in FIG.

As shown in FIGS. 4 and 5, the commands are M sub-scanning color shift amount information command F1 (H), C sub-scanning color shift amount notification command F2 (H), and Y sub-scanning color shift amount command. A notification command F4 (H) and a sub-scanning color shift amount notification command F7 (H) of Bk, and each command includes an error bit, color shift amount data, and a parity bit.
Returns the status of the byte.

The color shift amount data is composed of a sign bit and data. The sign bit is positive when "0" and negative when "1". The data has a resolution of 10 .mu.sec and BIT4 (MS).
B) to BIT0 (LSB). The resolution can be arbitrarily changed depending on the degree of color shift.

For example, when the color shift amount is “+20” μsec, the color shift amount data becomes “000010 (B)”.
000100 (B), 04 (H) ".

When the color shift amount is “−40” μm, the color shift amount data becomes “100100 (B)”, and when an error bit and a parity bit are added, “01001001” is obtained.
(B), 49 (H) ".

When the color shift amount of each color is notified to the controller unit 14 in this way, the controller unit 14 adjusts the time from transmitting the video signal to the vertical synchronizing signal for each color to the offset for canceling the color shift. Correct by the amount.

In the present embodiment, the time is measured with reference to the stop position of the photosensitive drum 12, but the calculation of the color shift amount with reference to a patch of a specific color can be considered as a development example. . Further, the patch may be formed not only on the photosensitive member but also on the transfer member.

In this embodiment, the amount of displacement is detected by sequentially forming patches of four colors. However, the same applies when the patches are formed by rotating the photosensitive drum four times with one color instead of four colors. The effect is obtained. At that time, the shift amounts of the first, second, third, and fourth patches are calculated for the first color, the second color,
Similar processing may be performed for the displacement amounts of the third and fourth colors. Alternatively, four patches may be formed by switching between two colors and three colors instead of one color.

[Second Embodiment] FIG. 6 is a view for explaining the arrangement of an image forming apparatus according to a second embodiment of the present invention. In FIG. It is attached.

In the figure, reference numeral 11a denotes the optical sensor 11;
13d1, 13d2, an optical sensor (sensor) equivalent to
13d3 and 13d4 are patches of toner of a specific color (for example, black) transferred onto the photosensitive drum 12, and t ₁ ′,
At t ₂ ′, t ₃ ′, and t ₄ ′, the patches 13d1, 13d2, 13d3, 1
It represents the time until 3d4 is detected.

The sensors 11 and 11a are installed in parallel to the rotation direction of the photosensitive drum 12, and the color patches 13a and 13d1, the color patches 13b and 13d2, the color patches 13c and 13d3, and the colors 13d and 13d are provided.
d4 is also formed on the photosensitive drum 12 in parallel. These color patches 13a, 13b, 13c, 13d and patch 13d
1, 13d2, 13d3, 13d4 are formed on the photosensitive drum 12 without being shifted on the signal. Here, the patches 13d1, 13d2, 13d3, and 13d4 are formed in a specific color (for example, black), and the two optical sensors 11 and 11a detect the time from a state in which the photosensitive drum 12 is stopped at the same time as the parallel patches. I do.

Hereinafter, this embodiment will be described with reference to FIG.

In the second embodiment, an image forming means for forming an image on an image carrier and a plurality of developing means (developing units) for developing the image formed by the image forming means with developers of different colors 64a to 64d, a generating unit (image not-shown sensor not shown) for generating a predetermined reference signal in accordance with the rotational driving of the image carrier, operating in accordance with the reference signal, First detecting means (sensor 11) for reading a plurality of different-color patch images formed on the body and detecting their positions, respectively, and operating in accordance with the reference signal; forming on the image carrier by the image forming means; Second detecting means (sensor 11a) for reading the plurality of same-color patch images thus detected and detecting their positions, respectively, based on outputs of the first detecting means and the second detecting means. Second calculating means (CPU that calculates a positional shift amount of each color image formed by the image forming means
60) and correcting the image forming timing in the sub-scanning direction of the image forming unit to form each color image after detecting the predetermined reference signal based on the positional shift amount calculated by the second calculating unit. Second control means (CPU 60
M, etc., to execute correction control), and operates in response to a TOP signal generated by the image leading edge sensor, and a plurality of different colors formed on the image carrier by the image forming means. The sensor 11a reads a patch image and detects its position, and operates according to the reference signal. The sensor 11a reads a plurality of same-color patch images formed on the image carrier by the image forming means and reads the patch image. After detecting the positions, the CPU 60 calculates the amount of positional deviation of each color image formed by the image forming means based on the detected positions, and corrects the timing of generating the TOP reference signal based on the calculated amount of positional deviation. Then, the image data is transferred to the controller unit 14 to correct the image forming timing in the sub-scanning direction of the image forming unit for forming each color image. Since, it is possible to transfer position in the sub-scanning direction of each color image is accurately corrected to form a color image without color misregistration.

Further, the image forming means is arranged so that each different-color patch image and each same-color patch image are continuously formed along the moving direction of the image carrier, and each different-color patch image and each same-color patch image are formed as the image. Since it is formed so as to be juxtaposed along the direction orthogonal to the moving direction of the carrier, the transfer position deviation of each color image in the sub-scanning direction can be accurately detected by the plurality of detecting means (sensors 11 and 11a). .

Each of the different color patch images is formed by performing four image forming operations on the photosensitive drum 12 in the same manner as in the first embodiment, and each same color patch image is formed by one image forming operation. It is formed by performing.

FIG. 7 shows each of the sensors 11 and 11 shown in FIG.
FIG. 6 is a characteristic diagram illustrating a density change of each patch detected by a, where the vertical axis indicates density and the horizontal axis indicates time.

In the figure, t ₁ and t ₁ ′ indicate the respective detection times. The difference between the detection time t ₁ and the detection time t ₁ ′ is
There is a shift amount of any color for a particular color, similarly, the detection time t ₂ and the detection time t ₂ of the 'with the detection time t ₃ and detects the time t _3', the detection time t ₄ and the detection time t ₄ The CPU 60 calculates the difference between the two colors, and the shift amount between the colors is obtained. Then, the same processing as in the first embodiment is performed to correct the color shift.

In this embodiment, two optical sensors are used.
Although a plurality is provided, a plurality may be further provided. Like this
By installing a large number, it is possible to simultaneously read multi-color misregistration information, thereby improving the processing speed.

In the present invention, as described above, without forming the same color patches, the positional deviation between the first color, the second color, the third color, and the fourth color based on the first color of each different color patch is used as a reference. Upon detection, the same processing as in the first embodiment may be performed.

[Third Embodiment] In each of the embodiments described above, color shift correction in the sub-scanning direction has been described. However, the present invention is also applicable to color shift correction in the main scanning direction. Hereinafter, the embodiment will be described.

FIG. 8 illustrates the structure of an image forming apparatus according to a third embodiment of the present invention. The same reference numerals as in FIGS. 1 and 6 denote the same parts. 9 is a timing chart for explaining the operation shown in FIG. FIG. 8 corresponds to the periphery of the photosensitive drum 12 where a patch is created.

In the figure, 11b is the sensor 11, 1
An optical sensor (sensor) equivalent to 1a is arranged in the main scanning direction as shown.

The sensor 11 has a dashed line 3 around the dashed line 300b.
00a to the dashed line 300c, the sensor 11a
Are from the broken line 300b to the broken line 300d around the broken line 300c.
And the sensor 11b reads from the broken line 300c to the broken line 300e around the broken line 300d. The other configuration is the same as that of the above-described embodiment, and the description is omitted.

The patches 13a, 13b, 13c, 1
The width of 3d is the same as the sensor reading width.

For example, when the sensor reading width is 4 mm, the interval between the broken lines is 2 mm (half of 4 mm),
Each patch has a width of 4 mm.

The density read value is taken into an analog port (not shown) of the CPU 60, and becomes “5” v when the patch is located 100% within the read width, and becomes “0” v when all the patches are out of the read width. . During this time, it changes linearly. (For example, if the position is 50% of the patch reading width, the value is "2.5" v.) A density reading strobe is provided for each sensor, and the read value is determined at the falling edge of the strobe signal. Since the sensors are arranged in line, each density reading strobe takes time t300.
Delayed by minutes. t300 is determined by the width of the sensor and the process speed of the image recording apparatus.

A method of reading the density of the patches arranged on the photosensitive drum 12 shown in FIG. 8 and a method of calculating the deviation in the main scanning direction will be described. For example, in FIG. 8, the patches 13a of Bk, the patches 13b of M, the patches 13c of Y, and the patches 13d of C are arranged in this order. Sensor 11, 11
a and 11b read the density of each color in the above order. Here, it is assumed that the densities of the respective colors are at the same level. Since the method of unifying the concentration levels is a known technique, the description is omitted.

First, the sensors 11, 11a, 11b
Reads the density of the black (Bk) patch 13a. “2.5” v is obtained from the sensor 11, “5” v is obtained from the sensor 11a, and “2.5” v is obtained from the sensor 11b. The black (Bk) patch 13a is indicated by a broken line 300a.
From the broken line 300b to 50%, and from the broken line 300b to the broken line 3
It is located 100% within 00d and 50% within dashed line 300c to 300e.

Next, the sensors 11, 11a and 11b read the density of the magenta (M) patch 13b. "5" v from the sensor 11, "2.5" from the sensor 11a
v, “0” v is obtained from the sensor 11b, and the magenta (M) patch 13b
100% within c, and 5 from dashed line 300b to dashed line 300d
0% and 0% from the broken line 300c to the broken line 300e.

Next, the sensors 11, 11a and 11b read the density of the yellow (Y) patch 13c. “1.25” v from the sensor 11 and “3.
75 "v and" 3.75 "v are obtained from the sensor 11b, and the yellow (Y) patch 13c is 25% within the dashed line 300a to the dashed line 300c, and is 30% from the dashed line 300b.
75% in 0d, 7 from broken line 300c to broken line 300e
5%.

Finally, the sensors 11, 11a and 11b read the density of the cyan (C) patch 13d. Sensor 11
, "2.5" v is obtained from the sensor 11a, and "2.5" v is obtained from the sensor 11b.
The patch 13d of FIG.
0%, 100% within dashed line 300d from dashed line 300b, and 50% within dashed line 300e from dashed line 300c.

50 from the broken line 300a to the broken line 300c.
%, 100% within the dashed line 300d from the dashed line 300b, and 50% within the dashed line 300e from the dashed line 300c, the deviation amount of the black (Bk) patch 13a is "0" mm, and the magenta (M) The shift amount of the patch 13b is “−2 mm”, the shift amount of the yellow (Y) patch 13c is “+1” mm, and the shift amount of the cyan (C) patch 13d is “0” mm.

There is a method of notifying the amount of displacement to the controller unit 14 by notifying the distance and time. The method is previously determined with the controller unit 14. In the present embodiment, the notification is made by time, which is obtained by dividing the shift amount represented by the distance by the main scanning speed.
When 0 m / sec, the deviation time of black (Bk) is “0” μsec, and the deviation time of M is “−20” μsec.
The shift time of c and Y is “10” μsec, and the shift time of C is “0” μsec.

A black (Bk) main scanning shift time notification command is E0 (H), a magenta (M) main scanning shift time notification command is E3 (H), and a yellow (Y) main scanning shift time notification command is E5. (H), the main scanning shift time notification command of cyan (C) is set to E6 (H), and the resolution of the status data portion is set to 10 μsec. The method of transmitting / receiving the command / status is the same as that of the above-described embodiment, and thus the description is omitted.

In the controller section 14, the time from when the horizontal synchronizing signal for each color is transmitted to when the video signal is transmitted is determined.
The shift amount transferred from U60 is corrected.

Hereinafter, the present embodiment will be described.

In the third embodiment, an image forming means for forming an image on an image carrier and a plurality of developing means (developing unit) for developing the image formed by the image forming means with developers of different colors 64a to 64d), a synchronization generating unit (a BD sensor (not shown)) for generating a synchronization signal in the main scanning direction with respect to the image carrier, operating in response to the synchronization signal, and operating on the image carrier by the image forming unit. A plurality of detecting means (sensors 11, 11 a, 1) for reading the formed plurality of different color patch images and detecting the effective patch image areas in the main scanning direction orthogonal to the moving direction of the image carrier.
1b are arranged at the intervals shown in the figure), a calculating means (CPU 60) for calculating the amount of displacement in the main scanning direction of each color image formed by the image forming means based on the output of each detecting means, Control means for detecting the synchronizing signal based on the amount of displacement in the main scanning direction calculated by the calculating means and correcting the image forming timing in the main scanning direction of the image forming means for forming each color image (not shown by CPU 60) A correction program is executed by executing a control program stored in a ROM), and operates in response to a synchronization signal (BD signal) generated from a BD sensor, and is formed on the image carrier by the image forming means. Each of the sensors 11, 11a, and 11b reads a plurality of different-color patch images, and detects an effective patch image area in the main scanning direction orthogonal to the moving direction of the image carrier. Based on the detection output, the CPU 60 calculates the amount of displacement in the main scanning direction of each color image formed by the image forming means, detects a BD signal based on the calculated amount of displacement in the main scanning direction, and then converts each color image. Since the image forming timing of the image forming means to be formed in the main scanning direction is corrected, the misregistration area of each different color patch in the main scanning direction is reliably detected, and the transfer position of each color image in the main scanning direction is accurately detected. Correction can form a color image without color misregistration.

In order to improve the accuracy of the color misregistration measurement in the main scanning direction, a sensor having a narrow reading width is used, a plurality of sensors are narrowed in a row, and the width of a patch in the main scanning direction is increased. It becomes possible by narrowing.

In this embodiment, the sensor is 3
However, it is needless to say that in an image forming apparatus in which the sensor reading width and the patch width are the same and the deviation amount is minute, the same operation can be performed by disposing the edge of the patch at the center of the sensor reading. No.

The present invention may be applied to a system composed of a plurality of devices or an apparatus composed of one device. Needless to say, the present invention can be applied to a case where the present invention is achieved by supplying a program to a system or an apparatus. In this case, by reading a storage medium storing a program represented by software for achieving the present invention into the system or the apparatus, the system or the apparatus can enjoy the effects of the present invention. .

Further, by downloading and reading out a program represented by software for achieving the present invention from a database on a network by a communication program, the system or apparatus can be
It is possible to enjoy the effects of the present invention.

Further, in each of the embodiments, a light emitting section for emitting a laser beam modulated on an image carrier based on image information, and a rotary polygon mirror for deflecting the laser beam emitted from the light emitting section are provided. And an optical system for forming an image of the deflected laser beam on the image carrier. Further, the image carrier includes a photosensitive drum and an intermediate transfer material to which an image developed on the photosensitive drum is transferred.

According to each of the above-described embodiments, it is possible to prevent the image blur and the image from appearing double due to the color misregistration.
Image quality can be improved. In addition, it is possible to correct deterioration in the amount of color misregistration in the sub-scanning direction and the main scanning direction due to mechanical differences between image forming apparatuses, differences due to environmental changes, and deterioration of components due to durability.

Further, since the sensor 11 also serves as a density sensor, no new circuit or component is required for the patch image detecting mechanism, so that the cost of the patch image detecting mechanism can be reduced.

Further, since the image forming apparatus performs the correction processing in a short time at a predetermined timing (when the power is turned on, each time a predetermined number of images are formed, every time after a predetermined time elapses, etc.), the user always has an image without any positional displacement. Can be continuously formed.

In the above embodiment, the position shift of each color is controlled by changing the output timing of the image signal from the controller unit 14. However, each direction described in the above embodiment is controlled. (Main scanning / Sub scanning)
The information on the shift amount of each color is
), And the load on the printer body can be reduced if the external image signal generator controls the image signal output timing.

Further, the computer 1000 (see FIG. 10) may display on the monitor in accordance with the shift amount, and may display the shift amount of each color as it is, determine whether or not to cancel the output of the image signal, and the like. Performing display or the like for selection is also included in the present invention. That is, the present invention includes performing some processing for the amount of deviation by an external image signal generating device.

[Other Embodiments of the Present Invention] Even if the present invention is applied to a system composed of a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), one device (for example, a copying machine, Facsimile machine).

Further, in order to realize the functions of the above-described embodiments, a device connected to the various devices or a computer in a system is operated so as to operate various devices so as to realize the functions of the above-described embodiments. The present invention also includes programs implemented by supplying the program code of the software described above and operating the various devices according to a program storing a computer (CPU or MPU) of the system or apparatus.

In this case, the software program code itself implements the functions of the above-described embodiment, and the program code itself and means for supplying the program code to a computer, for example, the program The storage medium storing the code constitutes the present invention.

As a storage medium for storing such a program code, for example, a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, magnetic tape, nonvolatile memory card, ROM or the like can be used.

When the computer executes the supplied program code, not only the functions of the above-described embodiment are realized, but also the OS (operating system) in which the program code operates in the computer, or Needless to say, the program code is also included in the embodiment of the present invention when the functions of the above-described embodiment are realized in cooperation with other application software or the like.

After the supplied program code is stored in a memory provided in a function expansion board of a computer or a function expansion unit connected to the computer, the function expansion board or the function expansion unit is specified based on an instruction of the program code. It goes without saying that the present invention also includes a case where the CPU or the like provided in the first embodiment performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

[0095]

As described above, according to the present invention,
A control signal for controlling a timing for detecting a plurality of position detection images formed on the image carrier and generating a plurality of color image signals by performing a plurality of surface image forming operations is generated in a predetermined or external manner. Since the output is output to the means, it is possible to start the formation of the surface image of each color at a timing at which the positional deviation of the plurality of position detection images formed on the image carrier is canceled out, so that the surface image of each color can be superimposed accurately. .

Further, according to the present invention, by performing a plurality of surface image forming operations, a plurality of position detection images formed so as to be juxtaposed on the image carrier are detected to generate a plurality of color image signals. A control signal for controlling the timing for output is output to a predetermined or external generating means, so that the surface image formation of each color is started at a timing at which the positional deviation of the plurality of position detection images formed on the image carrier is offset. Thus, the surface images of the respective colors can be superimposed with high accuracy.

Further, by performing a plurality of surface image forming operations, a plurality of position detection images formed on the image carrier are detected, and a control signal for controlling timing for generating a plurality of color image signals is externally provided. Since the electronic device receives and the electronic device controls the output timing of a plurality of color image signals,
On the image forming apparatus side, it is possible to start image formation based on the surface image information of each color received at the timing at which the positional deviation of the plurality of position detection images formed on the image carrier is canceled, and the surface image of each color is It can be superimposed with high accuracy.

Further, according to the present invention, each detecting means operates in response to a synchronizing signal generated from a synchronizing means, and reads a plurality of different color patch images formed on the image carrier by the image forming means. The effective patch image area in the main scanning direction orthogonal to the moving direction of the image carrier is detected respectively, and based on each detection output, the calculating means shifts the main scanning direction position shift of each color image formed by the image forming means. Since the control means detects the synchronizing signal based on the calculated positional deviation amount in the main scanning direction, the image forming timing in the main scanning direction of the image forming means to form each color image is corrected. A misregistration area in the main scanning direction of each different color patch can be reliably detected, and a transfer position of each color image in the main scanning direction can be accurately corrected to form a color image without color misregistration.

Therefore, it is possible to obtain a high quality color image by transferring a different color image onto the image carrier without displacement, without being affected by a change over time.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a main configuration of an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a characteristic diagram showing a change in density patch detection by the sensor shown in FIG. 1;

FIG. 3 is a timing chart illustrating a communication process between a CPU and a controller unit illustrated in FIG. 1;

FIG. 4 is a diagram illustrating an example of a command / status between a CPU and a controller unit illustrated in FIG. 1;

FIG. 5 is a diagram illustrating an example of a command / status between a CPU and a controller unit illustrated in FIG. 1;

FIG. 6 is a diagram illustrating a configuration of an image forming apparatus according to a second embodiment of the present invention.

FIG. 7 is a characteristic diagram illustrating a density change of each patch detected by each sensor illustrated in FIG. 6;

FIG. 8 is a diagram illustrating a configuration of an image forming apparatus according to a third embodiment of the present invention.

9 is a timing chart illustrating the operation shown in FIG.

FIG. 10 is a schematic sectional view illustrating the configuration of this type of image forming apparatus.

[Explanation of symbols]

 Reference Signs List 11 sensor 12 photosensitive drum 13a patch 13b patch 13c patch 13d patch 60 CPU

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location G03G 21/14 G03G 21/00 372 H04N 1/46 H04N 1/46 Z

Claims (18)

[Claims] An image forming apparatus that forms a color image by superimposing a surface image on an image carrier every time the image carrier makes one rotation based on image signals of a plurality of colors generated by predetermined generating means. Forming means for forming a plurality of position detection images by performing a plurality of image forming operations on the image carrier; detecting means for detecting each position of the plurality of position detection images formed by the forming means And an output unit for outputting a control signal for controlling generation timing of each of the plurality of image signals by the predetermined generation unit based on the position detected by the detection unit. . 2. An image forming apparatus which forms a color image by superimposing on an image carrier based on a plurality of color image signals generated by an external generating means, wherein a plurality of image forming operations are performed on the image carrier. Forming means for forming a plurality of position detection images, detecting means for detecting respective positions of the plurality of position detection images formed by the forming means, and a position detected by the detecting means. An output unit that outputs information to the external generating unit. 3. The image according to claim 1, further comprising control means for controlling the generation timing of each of the plurality of color image signals by said predetermined generation means based on said control signal. Forming equipment. 4. The image forming apparatus according to claim 1, wherein the forming unit forms the position detection image using a plurality of colors used for forming the color image. 5. The image according to claim 1, wherein the forming unit forms the position detection image using a smaller number of colors than a plurality of colors used for forming the color image. Forming equipment. 6. The image forming apparatus according to claim 1, wherein the detection of each position by the detection unit is performed by a single detection unit. 7. The image forming apparatus according to claim 1, wherein each position by said detecting means is performed by a plurality of detecting means. 8. An image forming apparatus which forms a color image by superimposing a surface image on an image carrier each time the image carrier makes one rotation based on image signals of a plurality of colors generated by predetermined generating means. By performing a plurality of surface image forming operations on the image carrier,
A first forming means for forming a plurality of position detection images, and a plurality of position detection images formed by the first forming means by performing a single surface image forming operation on the image carrier; A second forming unit for forming a plurality of position detection images, a plurality of position detection images formed by the first forming unit, and positions of the plurality of position detection images formed by the second forming unit And output means for outputting a control signal for controlling the generation timing of each of the image signals of a plurality of colors by the predetermined generating means based on the position detected by the detecting means. Characteristic image forming apparatus. 9. An image forming means for forming an image on an image carrier, a plurality of developing means for developing an image formed by the image forming means with developers of different colors, and a main scan on the image carrier. A synchronization generating means for generating a direction synchronization signal, operating in response to the synchronization signal, reading a plurality of different color patch images formed on the image carrier by the image forming means, and moving the image carrier. A plurality of detecting means for respectively detecting an effective patch image area in the orthogonal main scanning direction; and calculating means for calculating a main scanning direction positional deviation amount of each color image formed by the image forming means based on an output of each detecting means. And correcting the image forming timing in the main scanning direction of the image forming unit to form each color image after detecting the synchronization signal based on the main scanning direction displacement calculated by the calculating unit. An image forming apparatus comprising: 10. An electronic apparatus for generating a plurality of surface image signals and outputting the image signals to an external image forming apparatus, wherein the external image forming device performs a plurality of surface image forming operations on a predetermined image carrier. A receiving unit for receiving information based on a relative positional shift amount of each surface image formation when performing, and each of the plurality of surface image signals is output to the external image based on information received by the receiving unit. Control means for controlling output timing for outputting to the forming apparatus. 11. The electronic device according to claim 10, wherein the electronic device is a computer that outputs a color image signal to the image forming apparatus. 12. An electronic apparatus for generating a plurality of plane image signals and outputting the plane image signals to an external image forming apparatus, wherein the external image forming apparatus forms a plurality of plane image signals on a predetermined image carrier. It has a receiving means for receiving information based on a relative displacement amount of each surface image formation when performing an operation, and a display means for performing display according to the information received by the receiving means. Electronics. 13. An image forming method for forming a color image by superimposing a surface image on an image carrier every time the image carrier makes one rotation based on image signals of a plurality of colors generated by predetermined generating means. A forming step of forming a plurality of position detection images by performing a plurality of image forming operations on the image carrier, a detection step of detecting each position of the formed plurality of position detection images, An output step of outputting a control signal for controlling generation timing of each of the plurality of image signals by the predetermined generation unit based on the detected position. 14. An image forming method for forming a color image by superimposing on an image carrier based on image signals of a plurality of colors generated by an external generating means, wherein a plurality of image forming operations are performed on the image carrier. Performing, a forming step of forming a plurality of position detection images, a detection step of detecting each position of the formed plurality of position detection images, and information based on the detected positions, And an output step of outputting to the generating means. 15. An image forming method for forming a color image by superimposing a surface image on an image carrier every time the image carrier makes one rotation based on image signals of a plurality of colors generated by predetermined generating means. By performing a plurality of surface image forming operations on the image carrier,
A first forming step of forming a plurality of position detection images, and performing a single surface image forming operation on the image carrier, thereby different from the plurality of position detection images formed by the first forming unit. A second forming step of forming a plurality of position detection images, positions of the plurality of position detection images formed in the first forming step, and a plurality of position detection images formed in the second forming step And an output step of outputting a control signal for controlling the generation timing of each of the image signals of a plurality of colors by the predetermined generation unit based on the detected position. Image forming method. 16. A computer for forming a color image by superimposing a surface image on the image carrier each time the image carrier makes one rotation based on image signals of a plurality of colors generated by predetermined generating means. A storage medium storing a possible program code, wherein a plurality of image forming operations are performed on the image carrier to form a plurality of position detection images; A program code for a detecting step of detecting each position of the image; and an output step of outputting a control signal for controlling generation timing of each of the plurality of image signals by the predetermined generating means based on the detected position. A storage medium storing a computer readable program code including the program code. 17. A computer-readable storage medium storing a computer-readable program code for performing an image forming process of forming a color image by superimposing on an image carrier based on image signals of a plurality of colors generated by an external generating means. A program code for a forming step of forming a plurality of position detection images by performing a plurality of image forming operations on the image carrier; and a detecting step of detecting respective positions of the formed plurality of position detection images. A computer-readable storage medium for storing a computer-readable program code including: a program code for outputting a program code; and a program code for an output step of outputting information based on the detected position to the external generating means. 18. A computer for forming a color image by superimposing a plane image on the image carrier every time the image carrier makes one revolution based on image signals of a plurality of colors generated by predetermined generating means, and reading the color image. By performing a plurality of surface image forming operations on an image carrier in a storage medium storing possible program codes,
A program code for a first forming step of forming a plurality of position detection images, and a plurality of position detection images formed by a first forming unit by performing one surface image forming operation on the image carrier. A program code of a second forming step for forming a plurality of position detection images different from the plurality of position detection images, a plurality of position detection images formed in the first forming step, and a plurality of position detection images formed in the second forming step A program code for a detection step of detecting a position with respect to the position detection image; and an output for outputting a control signal for controlling the generation timing of each of the plurality of color image signals by the predetermined generation means based on the detected position. A storage medium storing a computer readable program code including a process program code.