JPS62263771A - Image forming device - Google Patents

Abstract

PURPOSE:To transfer an image signal to plural printers and to form plural images at the same time by correcting a transfer timing to the succeeding printer of the image signal read synchronously with a preceding image writing permission signal. CONSTITUTION:The control unit 8 of a successive unit 7 decides the order of the image writing permission signals ITOPA and ITOPB from the position sensors 11a, 12a of color printers 11, 12 and outputs an image reading start signal RSTART to a color reader 51 synchronously with the ITOPA, for instance, when the ITOPA precedes to the ITOPB. A synchronization control part 9 controls the transmission of the image signal VIDEO transmitted from the color reader 51 and written in a successive memory 10 to the synchronizing memory 12b of the printer 12. Synchronization control parts 11c and 12c read the image signals from synchronization memories 11B, 12b and output an ON and OFF signal to the semiconductor lasers 11e, 12e through gradation control circuits 11d, 12d.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention consists of a reader that converts an optical image into an electrical signal, and a printer that forms an image based on the digital signal output from the reader. The present invention relates to an image forming apparatus.

[Conventional technology]

Conventionally, when obtaining a hard copy of a color image, for example, a color printer using a thermal transfer method or an electrophotographic method typically prints Y (yellow), 2M (magenta), C (cyan), and BK.
A hard copy of a full-color (golden) image is obtained by a so-called subtractive color mixing method in which (black) color developing materials are successively superimposed. In this case, it is necessary to accurately match the Y image, 2M image, and C image onto the recording medium (recording paper).

Therefore, when printing color image information read by a color image reading device (color reader) one after another in real time, or when there is no image memory,
A synchronized control method for superimposing color images between a color reader and a color printer was needed.

FIG. 8 is a sectional view illustrating the outline of a color copying machine, which has a color reader 51 at the top and a color printer 52 at the bottom. This color reader 51 reads the color image information of the document for each color using color separation means and a photoelectric conversion element such as CCb, which will be described later, and converts it into an electrical digital signal. The color printer 52 is an electrophotographic laser beam printer that reproduces a color image in each color according to the digital image signal and records the image by transferring it to recording paper multiple times in the form of digital dots.

First, an overview of the color reader 51 will be explained.

Reference numeral 53 denotes a document, and 54 denotes a document scanning unit that scans the document 53. The document scanning unit 54 includes a rod array lens 552, a same-magnification color separation line sensor (color image sensor) 56, and an N-light lamp 57.

58 is the wiring code for the document scanning unit 5°4; 59
is a cooling fan, and Boa is a signal processing board, which performs signal processing for sending the output of the color image sensor 56 to the image processing unit 60b through the wiring cord 58.

When the document scanning unit 54 moves and scans in the direction of arrow A in the figure to read the image of the document 53 on the document table, the exposure lamp 57 in the document scanning unit 54 is turned on at the same time.
Reflected light from the original 53 is guided by a rod array lens 55 and focused on a color image sensor 56, which is a color information reading sensor.

Further, 61 is an actuator provided at the bottom of the document scanning unit 54, and 62a and 82b are position sensors.
The scanning position of the document scanning unit 54 is detected via the actuator 61 . Position sensors 62a, 62
b is composed of a micro switch and the like.

Next, an outline of the color printer 52 will be explained.

71 is a scanner, a laser output unit that converts the image signal from the color reader 51 into an optical signal, and a polygon mirror 72 of a polyhedron (for example, dodecahedron). A motor (not shown) that rotates this polygon mirror 72 and an imaging lens 73
etc. A reflecting mirror 74 changes the optical path of the laser beam. 75 is a photosensitive drum, 76 is a primary charger, 77 is a separation static eliminator, 78 is a full-surface exposure lamp, and 79 is a cleaner section that collects residual toner that has not been transferred.

80 is a pre-transfer charger, and these members are connected to the photosensitive drum 75.
are arranged around.

A developing unit 81 develops an electrostatic latent image formed on the surface of the photosensitive drum 75 by laser exposure. 82 is a screw for transporting the developing material. 83y, 83M
, 83C, and 838 have toner hoppers that hold spare toner, and 84Y.

84M, 84C, and 848 are developer units 8 that directly perform development by contacting the photosensitive drum 75 with developing sleeves.
1 is the screw 82. Toner hopper 83Y,
83M, 83c, 838 and developing sleeves 84Y, 84s, 84c, 84ox, and these members are arranged around the rotation axis P of the developing unit 81. For example, when forming a yellow toner image, The figure is yellow, wearing the position shown in the figure.

When performing toner development to form a magenta toner image,
The developing unit 81 is rotated about the P axis shown in FIG. 1, and the developing sleeve 84M in the magenta developing unit is placed in contact with the photosensitive drum 75. Cyan and block development operate in the same way.

A transfer drum 85 transfers the toner image formed on the photosensitive drum 75 onto recording paper. 86 is an actuator plate that detects the moving position of the transfer drum 85. A position sensor 87 detects when the transfer drum 85 has moved to the home position by coming into contact with the actuator plate 86. 88 is a transfer drum cleaner, 89 is a paper press roller, and 9o is a transfer charger.

On the other hand, 92 and 93 are paper feed cassettes that accommodate recording paper. Paper feeding rollers 92a and 93a feed recording paper.

Timing rollers 94a to 94c determine the timing of paper feeding and conveyance. A paper guide 95 causes a gripper to carry the fed recording paper and wrap it around the transfer drum 85, thereby moving it to the image forming process.

A peeling claw 96 removes the recording paper from the transfer drum 85 after the image forming process is completed, and a transport belt 97 transports the removed recording paper. Reference numeral 98 denotes an image fixing section, and the image fixing section 98, which fixes the recording paper conveyed by the conveyance belt 97, is composed of a pair of heat pressure rollers 98a and 98b.

Next, the image forming operation will be explained with reference to FIGS. 9(a) and 9(b).

FIGS. 9(a) and 9(b) are operation explanatory diagrams illustrating image forming timing.

In these figures, T is the leading edge of the document 53. The reflected light from the surface of the original 53 is guided to the rod array lens 55 of the original scanning unit 54, and the image is sequentially read and captured by the color image sensor 56.

On the other hand, an actuator 61 is attached to the lower part of the document scanning unit 54, and a position sensor (DTOP sensor) 62a fixedly installed on the main body and a DTOP
A position signal is obtained from the sensor 62bc7).Normally, stopping is performed based on the output signal of the DTOP sensor 62a, and reading of the document is performed based on the output of the DTOP sensor 62b.

In the color printer 52, an image is written at a laser exposure position PH on the photosensitive drum 75. Further, on the circumference of the transfer drum 85, there is a position sensor (ITOP-1) 100 fixedly installed on the main body, and a position sensor (ITOP-1) installed on the circumference of the transfer drum 85.
The actuator plate 86 attached to the actuator plate 8 is arranged so that the leading edge of the recording paper to which the toner image is transferred is placed on the actuator plate 86 attached to the actuator plate 8.
6 is held by a gripper at point a.

Also, the circumferential length of the actuator plate 86 is a fixed intersection + α
and the DTOP sensor 62 in the color reader 51
It is slightly longer than between a and 62b.

First, when the ITOP sensor Too detects the tip a of the seven cutter plates 86 on the transfer drum 85, which is rotating at a constant speed in the direction of the arrow in the figure (clockwise direction), the scanning movement of the document scanning unit 54 is started. (see FIG. 9(a)), when the document scanning unit 54 comes to the DTOP sensor 62b, the document is read and therefore the synchronous memory has the following information:
The color-separated image whose reading is started from the leading edge T of the document is stored line by line.

On the other hand, on the color printer 52 side, when the rear end of the actuator plate 86 on the circumference of the transfer drum 85 is detected, reading from the beginning of the above-mentioned synchronous memory is performed from the time of detection of the rear end. Image writing onto the drum 75 is started (see FIG. 9(b)).

In this way, when the ITOP sensor 100 detects the leading edge a of the actuator plate 86 of the transfer drum 85, the exposure scanning of the original scanning unit 54 is started, and when the DTOP sensor 62b detects the leading edge T of the original 53, the original While reading the image and writing to the synchronous memory starts, the ITOP sensor 10 at the rear end of the actuator plate 86
At the same time as 0 is detected, image data is read from the synchronous memory.

[Problem that the invention seeks to solve]

However, when a plurality of color printers 52 are connected to one color reader 51, the following problems occur.

That is, the color printer 52 and the image forming apparatus that wraps the recording paper around the transfer drum 85 and transfers the image include an ITOP that determines the writing start position of the transfer drum 85.
A sensor 100 is provided, and after inputting image forming commands to a plurality of printers at the same time, initial setting operations such as pre-rotation are performed in preparation for normal image formation. At this time, ITO
The image writing start signal sent from the P sensor 100 to the color reader 51 varies from printer to printer, and some attempts have been made to absorb the variation with a large capacity memory means such as a page memory and send it to each printer. However, there were problems such as a significant increase in costs.

The present invention has been made to solve the above-mentioned problems, and is an image signal that is read out in synchronization with the preceding image write permission signal by determining the destination of each image write permission signal that is output before and after. It is an object of the present invention to provide an image forming apparatus that can transfer image signals read by a reader to a plurality of printers and simultaneously form a plurality of images by correcting the timing of transfer to a printer that is delayed.

[Means for solving problems]

The image forming apparatus according to the present invention includes a determining means for determining the destination of the image writing permission signal sequentially outputted from each image forming section, and outputting the image writing permission signal after receiving the first image writing permission signal outputted to the determining means. measuring means for determining the output interval of the image writing permission signal to be output by a total of ΔlII; A correction means for correction is provided.

[Effect]

In this invention, the discriminating means determines what comes after the image writing permission signal, and the image reading section starts reading the image in synchronization with the preceding image writing permission signal determined by the determining means, and the read image signal is transferred to the preceding image forming section. Further, the correction means corrects the timing at which the image signal read by the image reading section is transferred to the delayed image forming section in synchronization with the preceding image writing permission signal.

〔Example〕

FIG. 1 is a block diagram illustrating a control configuration of an image forming apparatus showing an embodiment of the present invention, and the same components as in FIG. 1 are given the same reference numerals.

In this figure, reference numeral 1 denotes an analog processing unit which processes B from the cyan signal (C signal), green signal (C signal), and yellow signal (Y signal) sequentially output from one chip of the color image sensor 56 for each pixel. (CG) signal, R(Y
- G) Create a signal. Since the output potential of the signal processed by the analog processing section 1 changes linearly with respect to the concentration, it is converted into a digital signal by, for example, an 8-bit A/D converter (not shown) in preparation for high-speed processing. 2 is a tunaki memory which synthesizes the digital signals processed by the analog processing section 1 and splices them into a 5-channel video signal within a horizontal synchronization signal section. 3 is the image processor unit)
(IPU) performs a shading correction process 9 to correct the light distribution of the video signal sent from the Tsunaki memory 2 and a masking process to correct the color tone. After completing each process, the IPU 3 converts it into an image signal VIDEO of 8 bits or less and outputs it to the multiplex unit 7. 4 is a synchronization signal processing section that synchronizes signal processing of the image processing section 60b in accordance with commands from the control unit 5. Reference numeral 6 denotes an operation unit for inputting various image processing modes.

The multiple unit 7 has a control unit 8. The control unit 8 is composed of a synchronous control section 99 and a multiple memory 10, and the control unit 8 receives image writing permission signals ITOPA and ITO sent from the ITOP sensors 11a and 12a of each color printer 11.12.
Determine the destination with PB, for example, send an image write permission signal I.
When TOPA precedes image writing permission signal ITOPB, image reading start signal RSTART is sent to color reader 5 in synchronization with image writing permission signal ITOPA.
1 control unit 5. After receiving the image writing permission signal ITOPA, the synchronization control unit 9 which also serves as the measurement and determination means of the present invention outputs the image writing permission signal ITOPA.
The time until receiving PB is counted by the horizontal synchronization signal RH5YNC generated by the color reader 51, and the image signal is written in the multiplex memory 10, which constitutes the correction means of the present invention, in synchronization with the image write permission signal ITOPA. Controls sending of VIDEO to the synchronous memory 12b of the color printer 12. Note that the image writing permission signal ITO
If PA is slower than the image write permission signal ITOFB, the above description is reversed and the image write permission signal ITO
When PA and the image write permission signal ITOPB are applied at the same time, the image signal VIDEO is synchronized with the image write permission signal ITOPA or the image write permission signal ITOPB.
is written to the synchronous memories 11b and 12b.

11e and 12c are synchronization control units, which control the color printer 11.
The horizontal synchronization signal PH3YNC for 12 and the clock PCLK for image transport are generated, and the synchronous memories 11b and 1
The gradation control circuit 11d reads out the image signal VI DEO stored in the gradation control circuit 11d.

12d performs known gradation processing, such as dither processing, and the semiconductor laser 11e of the scanner 71.

An on/off signal is output to 12e. 11f.

12f is a horizontal synchronizing signal (BD) sensor that receives the laser beams sent out from the semiconductor lasers 11a and 12e before image writing, and controls the BD double signal control units I1g and 12;
Output to g.

FIG. 2 is a block diagram illustrating the configuration of the control unit 8 shown in FIG.
The color printers 11, 12 (7) ITOP-t! Nsa lla,
Image writing permission signal ITOPA sent from 12a
, ITOPB, and the latch pulses LA, LB
is output to the subsequent latches 22a and 22b. A counter 23 counts the horizontal synchronization signal RH3YNC sent from the synchronization signal processing section 4, and is connected to a latch 22a.

A count signal is output to 22b. A comparator 24 compares the outputs of the latches 22a and 22b, determines the output order of the image write permission signals ITOPA and ITOPB, and outputs a comparison output CA.

CP, which will be described later, when the following conditions are met for CB and CC
Output to tJ31.

That is, the comparator output CA is output when the image write permission signal ITOPA is output before the image write permission signal TOFB, and the other comparator outputs CB and CC become "0". Also, comparator output C
B is output when the image write permission signal ITOPB is output before the image write permission signal ITOPA, and the other frequency outputs CA and CC are "0".

Furthermore, the comparator output CC1 is output when the image write permission signal ITOPA and the image write permission signal ITOPB are output at the same time, and the other comparator output C
A and CB become rOJ. 25a and 25b are by
7y, the outputs of latches 22a and 22b and their inverted outputs are held. 26 is an adder, eight buffers 25a,
25b is calculated, and the added value signals ADDE, A are calculated.
DDD is output to the control unit 8 and the synchronization control section 9.

Note that the counter 23 is cleared by the image reading start signal RSTART sent from the control unit 8.

3 [IN(a) is a block diagram illustrating the sending control operation of the image data VIDEO stored in the multiplexed memory 10 shown in FIG. 1, and the same parts as in FIG. are doing.

In this figure, 3] is a CPU constituting the data control means of the present invention, which is provided in the control unit 8 and receives comparator outputs CA, CB, CC and an addition value signal ADDE. 41a, 41b.

42 is a gate circuit with comparator outputs CA, CB, and C.
The image signal VIDEO stored in the ffI''a memory 10 or the direct image signal VIDEO sent from the IPU 3 is gated in accordance with the gate circuit 4 in the subsequent stage.
At 3.44, the video signal VIDEO is output. The gate circuits 43 and 44 have a comparator output CA from the CPU3.
, CB, CC, the control signal inputs a and b are output, and the image signal VIDEO is stored in the multiple memory 10.
Or direct image signal V sent from IPU3
Synchronous memory 11b of IDEO color printer 1i12
, , 12b is controlled according to the color mode signal. 45a and 45b are AND gates, and an image reading start signal R3TART that causes the color reader 51 to start reading an image when the first image writing permission signal ITOPA and image writing permission signal ITOPB are output from the color printers 11 and 12. mask the transmission of One end of the AND gates 45a and 45b is connected to a control signal c for masking the transmission of the image reading start signal R3TART.
, d are output from the CPU 31, and the AND gate 45a
, 45b are output to the OR gate 46.

FIG. 3(b) is a detailed block diagram illustrating the relationship between the synchronization control unit 9 and the multiple memory 10 shown in FIG. 3(a),
The same reference numerals are given to those performing the same a moat as in FIG.

In this figure, ADCOT is an address control unit, and the L
BMI NLBMN for a line determined by the difference between the first image write permission signal ITOPA and the image write permission signal ITOPB, that is, the horizontal synchronization signal RHSY
LB of the line buffer memory for a predetermined line according to the difference between the first image write permission signal ITOPA and the image write permission signal ITOPB counted by the NC.
Select MI to LBMN. VICOT is an image control unit that counts the horizontal synchronization signal RHSYNC and
LBMI of the line buffer memory where the address control unit ADCOT selects the image signal VIDEO sent from 3.
~Write to LBMN. Note that the address control unit ADCO
T secures a memory area for n+1 (1<n+1<N) lines when the number of differential lines between the first image write permission signal ITOPA and the image write permission signal ITOPB is n.

Next, the image forming control operation based on the difference between the first image writing permission signal ITOPA and the image writing permission signal ITOPB will be described.

When a print key (not shown) is pressed from the operation section 6, an operation command is sent from the control unit 5 of the color reader section 51 to the control units 11g and 12g of the color printer 11.12.

As a result, the color printer 11.12 starts a predetermined pre-rotation process, and the first image writing permission signal ITOPA is output from the ITOP sensors 11a and 12a.
and image writing permission signal engineer TOFB to color reader 51
The CPU 31 shown in FIG. 3(a) outputs the control signals c and d to the AND gates 45a and 45b so as not to output them to the AND gates 45a and 45b. On the other hand, the first image write permission signal ITOPA and the image write permission signal ITOPB output from the ITOP sensors lla and 12a are applied to the latch 2 shown in FIG.
It is also output to 1a and 21b. The horizontal synchronization signal R generated by the synchronization signal processing section 4 of the color reader 51 is sent to the latches 21a and 21b before the first image write permission signal ITOPA and image write permission signal ITOPB are sent.
H3YNC is input to the clock terminal CK. The latches 21a and 21b are the first image writing permission signal I.
When TOPA and the image write permission signal ITOPB are input, the latch pulses LA and LB are sent to the latch 22a in the subsequent stage.
, 22b. While the horizontal synchronizing signal RH3YNC is being sent to the latches 22a and 22b, the count signal sent from the counter 23 is sent out, and in synchronization with the latch pulses LA and LB, the count signal comparator 24 that has counted up to that point outputs the respective counts. The values are compared and the image write permission signal ITOPA and the image write permission signal I
If the image write permission signal ITOPA is output before the image write permission signal ITOPB, the comparator output CA is
On the other hand, the output of the latch 22b is sent to the buffer 25b, and based on this, the adder 26 sends the differential value signals ADDE and ADDD to the CPU 31 and synchronously. It is output to the control section 9. In response, the address control unit ADCOT of the synchronization control unit 9 reserves a predetermined line of the line buffer memories LBMI to LBMN in the multiplexed memory 1o for storing the image signal VIDEO. Then,
A second control unit for starting image reading from the control unit 8.
The second image writing permission signal, that is, the preceding image writing permission signal ITOPA, is output to the color reader 51 at a predetermined timing. As a result, the color reader 51 turns on the exposure lamp 57 and the document scanning unit 5
The reflected light is color-separated by the color image sensor 56, processed by the IFU 3 in response to the horizontal synchronization signal RH5YNC, and then sent to the preceding color printer 1.
], the processed image signal VIDEO is sent to the multiple unit 7
The data is sent directly to the synchronous memory 11b line by line via the synchronous memory 11b. On the other hand, the added value signal ADDE (line difference) calculated by the adder 26 is output to the address control unit ADCOT of the synchronization control unit 9. For example, if it is determined that there is a difference of 3 lines, the address control unit ADCOT Line buffer memories LBMI to LB in the multiple memory 10
Since a memory area for M4 (number of lines + 1 line) is secured, the image signals V1. When DEO is written to the line buffer memories LBMI to LBM4, for example, line buffer memories LBM4, LBM3, and LBM2, and the next horizontal synchronization signal RH3YNC is input, the image signal V for one line written to the line buffer memory LBM4 is I DEOl is read, and in parallel with this reading, the fourth
Write the image signal VIDEO4 of the th line, then read the image signal VIDEO2 for l life written to the line buffer memory LBM3, and in parallel with this reading, write the image signal of the 5th line to the line buffer memory LBM4. The operation of writing VIDEO5 is performed sequentially in synchronization with the horizontal synchronization signal RH3YNC. The image signals VIDEO written to the line buffer memories LBM1 to LBMN are sequentially written to the synchronous memory 12b of the delayed color printer 12, image formation in the first color mode is performed, and the image writing permission signal ITOPA is sent from the color printer 11. The image is output again, and image formation in the second color mode is performed in the same manner as described above. That is, the color mode specified on the operation unit 6 + one image writing permission signal ITOPA, the image writing permission signal I
TOPB is input to AND gates 45a and 45b,
Image reading is performed in synchronization with the preceding image writing permission signal ITOPA, and the image signal VIDEO for each line is read.
is sent to color printers 11 and 12 as described above.

Note that the image signal VI DEO is the color printer 11.1.
2, the horizontal synchronization signal PH3YNC and image signal VI generated by the synchronization control units 11c and 12c in the color printer 11.12
The processing speed is converted by the clock signal PCLK for conveying the DEO.

Next, referring to FIGS. 4 to 6, the control units 5, 8 . The operations of l1g and 12g will be explained.

FIG. 4 is a flowchart illustrating the operation of the control unit 5 in the color reader 51 shown in FIG. In addition,
(1) to (9) indicate each step.

First, execute the initial display routine 1), color reader 519 multi-unit unit 7, color printer 11.12
2) Wait for the start of startup to become OK.
When the print key (not shown) on the operation section 6 is pressed, the control unit 5 waits for the print key (not shown) to be pressed (3), and when it is pressed, the control unit 5 activates the control unit 8. color reader 1
1. Send the pre-scan operation command via the control unit 12) Ilg, 12g4), the control unit 11g,
A drive start signal is sent from 12g to the rotation drive system of the transfer drum to start the pre-rotation. As a result, image writing permission signals ITOA,
Wait for ITOPB to be sent5), and if No, send image write permission signals ITOA and ITO within a certain period of time.
PB is sent out, but it is necessary to judge whether it has been output or not.8.
), if NO, return to step (5), and if YES, execute the error handling routine (7).

On the other hand, in step (5), the image writing permission signal ITOP is
A, if ITOPB is sent out, multiple unit 7
The sequence according to the color mode is executed (8), and it is determined whether the color mode sequence is finished (9). If NO, the process returns to step (8), and if YES, the process returns to step (2).
).

FIG. 5 is a flowchart illustrating the operation of the control unit 8 of the multiple unit 5 shown in FIG. In addition, (1
) to (9) indicate each step.

First, execute the initial display routine 1), color reader 512 multi-unit unit 7, color printer 11.
2) If it is YES, the system will wait for the print key (not shown) on the operation panel 6 to be pressed. 4) , the first image writing permission signals ITOPA and ITOPB are masked by AND gates 45a and 45b so that they are not sent to the color reader 51 (5). Next, the calculated number of differential lines is the number of line buffer memories of the multiple memory 10, that is, LBM.
It is determined whether the full state exceeds N (6), and if YES, the control unit of the color printers 11 and 12 sends a command to move the output position of the image writing permission signals ITOPA and ITOPB output from the color printers 11 and 12. Output to 11g and 12g 7), step (2
), if No, outputs the second image writing permission signal, for example, the preceding image writing permission signal ITOPA, to the color reader 51, and also outputs the image signal VIDEO corresponding to the color mode to the color printer 11 or color printer 12. Gate circuit 43.44 to output
Turn on (8). Next, it is determined whether the designation of the gate circuits 43 and 44 has been completed (9). If NO, the process returns to step (8), and if YES, the process returns to step (4).

FIG. 6 is a flowchart for explaining the operations of the control units 11g and 12g of the color printer 11[deg.]2 shown in FIG. Note that (1) to (10) indicate each step.

First, execute the initial display routine 1), wait for the multi-unit unit 7 to be connected to the color printer 11, 12 2), wait for the end of warm-up after it is connected, 3), and if the printer has warmed up, Checks for toner out, and stores developed colors that cannot be formed by each color printer 11 and 12 in the internal memory of the control units 11g and 12g (
RAM) (4). Next, the system waits for the print key to be pressed (5), and when the print key is pressed, the pre-rotation process is executed (6), and as described above, the image writing permission signals ITOPA and ITOPB are sent to the control unit 8 of the multiple unit 7. will be sent to. Next, an image write permission signal I is output when the number of differential lines between the image write permission signals ITOPA and ITOPB exceeds the maximum number of lines in the line buffer memory of the multiple memory 10.
Determine whether a command to move the output position of TOPA and ITOPB has been output (7), and if YES, move the transfer drum to that output position (8).
, Return to step (5), and if No, execute the color mode designation process 3), determine whether image formation based on the color mode designation process is completed 10), and if NO, return to step (9), If YES, return to step (2).

FIG. 7 is a timing chart of signals of each part shown in FIG. 1, and the same components as in FIGS. 1 to 3 are given the same reference numerals.

c7) In Figure 2, VSYNCA and VSYNCB are vertical synchronization signals, VIDEOA and VIDEOB are image signals. This shows a state in which signal B is sent to the color printer 12. Note that the image signal A and the image signal B are the same image signal, and the image signal B is sent out from the multiple memory 10.

In the above embodiment, the difference line is measured when the first image writing permission signals ITOPA and ITOPB are sent, and the first image writing permission signal ITOFA is
, when transmitting ITOPB, main image formation is not performed, and furthermore, difference line correction is not performed until image formation in the set color mode is completed, but every time image formation in a predetermined color is completed. It goes without saying that if the difference line measurement control is interrupted and the difference line is corrected again, the accuracy of preventing image shift can be further improved.Also, in the embodiment described in L, a color printer is used as an example. As described above, the present invention can be easily applied to an image forming apparatus that performs multiple transfers by winding transfer paper.

Further, in the above embodiment, the case where the image signal VI DEO read by the color reader 51 is sent to the color printers 11 and 12 was explained, but up to N printers can be connected, and when N printers are connected, for,
It is sufficient to provide N+1 heavy/counterfeit units 7.

[Effects of the Invention] As described above, the present invention includes a discriminating means for discriminating between image writing permission signals successively outputted from the image forming section, and a discriminating means that receives the first image writing signal outputted to the discriminating means. measuring means for measuring the output interval of the image writing permission signal that is output after the image writing permission signal is output after the image writing permission signal is output after the image writing permission signal is outputted after the image writing permission signal is outputted after the image writing permission signal is outputted after the image writing permission signal is outputted after the image writing permission signal is outputted after the image writing permission signal is outputted after the image writing permission signal is outputted after the image writing permission signal is outputted after the image writing permission signal is outputted after the image writing permission signal is outputted after the image writing permission signal is outputted after the image writing permission signal is outputted from the image writing unit; Since a correction means for correcting the transfer timing is provided, image signals read from one reader can be sent simultaneously to multiple printers with different image writing timings, and multiple images can be simultaneously created by different printers. It has the advantage of being able to

[Brief explanation of drawings]

FIG. 1 is a block diagram explaining the control configuration of an image forming apparatus showing an embodiment of the present invention, FIG. 2 is a block diagram explaining the configuration of the control unit shown in FIG. 1, and FIG.
) is a block diagram explaining the sending control operation of the image signal stored in the multiplexed memory shown in Figure 1, and Figure 3(b) is a block diagram showing the synchronization control unit and multiplexed memory shown in Figure 3(a). 4 to 6 are flowcharts to explain the operation of each control unit shown in FIG. 1, and FIG. 7 is a detailed block diagram explaining the relationship between the two control units, and FIG. 7 shows the timing of signals of each part shown in FIG. 1. The chart, FIG. 8 is a sectional view illustrating the outline of the color copying machine, and FIGS. 9(a) and 9(b) are operation explanatory diagrams illustrating image forming timing. In the figure, 1 is the analog processing section, 2 is the Tsunagi memory, and 3 is the I
PU, 4 is a synchronization signal processing unit, 5 is a control unit, 6 is an operation unit, 7 is a multiple unit, 8 is a control unit (y), 10 is a multiple unit memory, 11.12 is a color printer, 11a, 12
a is an ITOP sensor, 11b and 12b are synchronous memories, I
lc and 12C are synchronization control units, 11f and 12f are BD sensors, 11g and 12g are control units, and 51 is a color reader. Figure 3 (a) Figure 3 (b) Figure 4 Figure 5 Figure 6 Figure 7 IDEOB

Claims (4)

[Claims] (1) In an image forming apparatus consisting of an image reading section that converts an image into an electrical signal and reads it, and a plurality of image forming sections that write the image signals read by this image reading section, each image forming section sequentially outputs the a measuring means for measuring an output interval of an image writing permission signal outputted after receiving a first image writing permission signal outputted to the determining means; An image forming apparatus comprising: a correction means for correcting the timing at which an image signal read by the image reading section is transferred to a delayed image forming section in synchronization with a preceding image writing permission signal determined by the means. (2) Claim (1) characterized in that the image signal read by the image reading section is directly transferred to the preceding image forming section in synchronization with the preceding image writing permission signal determined by the determining means. The image forming apparatus described above. (3) The image forming apparatus according to claim (1), wherein N-1 correction means are provided for N image forming units. (4) The image forming apparatus according to claim (1), wherein the correction means corrects the transfer timing of the image signal for a line corresponding to the delay time counted by the measurement means.