JPS62263773A - Image forming device - Google Patents

Abstract

PURPOSE:To successively form an image by an optional color when a developing material based on a chrominance picture signal is not stored in a printer by outputting only the chrominance signal capable of being formed based on remaining developing material information. CONSTITUTION:The picture processing part 60b of a color reader 51 forms a B(C-G) signal, an R(Y-G) signal from C, G, Y signals outputted from a color image sensor 56 and outputs a picture signal VIDEO. The control units 11g, 12g of the color printers 11, 12 check the absence from the output of toner remaining quantity detecting sensors 13, 14 and transmit a developing color which cannot be formed by the printers 11, 12 to the control unit 8 of a successive unit 7. The control unit 8 outputs a picture reading start signal RSTART to the color reader 51 and controls the transmission of the picture signal VIDEO written in a successive memory 10 to the synchronizing memory 12b of the color printer 12.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an image forming system consisting of a league that converts an optical image into an electrical signal and a printer that forms an image based on the digital signal output from this reader. It is related to the device.

[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), 9M (magenta), C (cyan), or BK.
A hard copy of a full-color (extra color) image is obtained by the so-called subtractive color mixing method in which (black) color developing materials are successively superimposed. In this case, it is necessary to accurately superimpose the Y image, the 2M image, and the C image on 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. The 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 a CCD, which will be described later, and converts the information into electrical digital signals. 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 represents an original, and 54 represents an original scanning unit that scans the original 53. The document scanning unit 54 includes a rod array lens 559, a same-magnification color separation line sensor (color image sensor) 56, and an exposure lamp 57. 58 is a wiring code for the document scanning unit 54; 59
60a is a cooling fan, and 60a is a signal processing board, which performs signal processing for sending the output of the color image sensor 56 to the image processing section 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 62b are position sensors.
The scanning position of the document scanning unit 54 is detected via the actuator 61 . The position sensors 62a and 62b are composed of microswitches 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. 8゛2
is a screw that transports the developing material. 83y, 83
8. Toner hoppers 83C and 838 hold spare toner. 84Y.

Developing sleeves 84M, 84c, and 848 contact the photosensitive drum 75 to directly perform development. The developing unit 81 includes the screw 82. Toner hopper 83y
, 83M, 83c, 838 and developing sleeves 84y, 84M, 84c, 848, these members are connected to the rotation axis P of the developing unit 81.
are arranged around. For example, when forming a yellow toner image, yellow toner development is performed at the position shown in this figure, and when forming a magenta toner image, the developing unit 81 is rotated around the P axis in the figure and exposed to light. A developing sleeve 84- in the magenta developing device is placed in contact with the 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 90 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 dot 85 to move 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. An image fixing section 98 fixes the recording paper conveyed by the conveyor belt 97. The image fixing section 98 is composed of a pair of thermopressure 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 images are sequentially read 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 based on the position of the sensor 62b. Normally, stopping is performed based on the output signal of the DTOP sensor 62a, and document reading 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, a position sensor (ITOP sensor) 100 fixedly installed on the main body and an actuator plate 86 attached to the transfer drum 85 are disposed on the circumference of the transfer drum 85, and a position sensor (ITOP sensor) 100 is disposed on the circumference of the transfer drum 85. The tip is held by a gripper at a point a at the tip of the actuator plate 86.

Also, the circumferential length of the actuator plate 86 is a fixed value + 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 100 detects the tip a of the actuator plate 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. (Refer to FIG. 9(a)), when the document scanning unit 54 comes to the DTOP sensor 62b, the document is read, and the synchronous memory stores the color-separated image line by line starting from the leading edge T of the document. Go.

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 seventh cutter plate 86 of the transfer drum 85, the exposure scanning of the original scanning unit 54 is started, and when the D-TOP sensor 82b detects the leading edge T of the original 53. At the same time, the rear end of the actuator plate 86 starts reading the original image and writing it to the synchronous memory.
At the same time as 00 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 recording paper around the transfer drum 85 and transfers the image are provided with an ITOP sensor 100 that determines the writing start position of the transfer drum 85, but when multiple printers are simultaneously After inputting an image formation command, initial setting operations such as pre-rotation are performed in preparation for normal image formation. At this time, ITOP
The image writing start signal sent from the 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. Furthermore, if there is more than one color of developing material corresponding to the color image signal in the color image signal, the printer determines that image formation is not possible and stops color image formation.
Even though development is possible with the remaining developing material, there are problems such as the system is treated as a downtime and the image forming efficiency is significantly reduced, or the recording medium of the photoreceptor is damaged when the image is formed.

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. By correcting the timing of transfer to the printer that is delayed, it is possible to transfer the image signal read by the reader to multiple printers and form multiple images at the same time. To provide an image forming device capable of continuing image formation in arbitrary colors when no material is stored in a printer.

[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. a measuring means for measuring the output interval of the image writing permission signal based on a synchronization signal generated by the image reading section; and an image reading section in synchronization with the image writing permission signal of the preceding image writing detector determined by the determining means. A correction means for correcting the transfer timing of the color image signal read by the image forming section to the image forming section, which is delayed, and an arbitrary color image signal among the color image signal sent from the correction means and the color image signal read by the image reading section. and a data control means for erasing the remaining color image signal and transmitting the remaining color image signal to the image forming section 5. [Operation] In the present invention, the determination 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 transfers the read image signal 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 image writing permission signal of the preceding image writing detector. Furthermore, the data control means erases any color image signal among the color image signals output from the image reading section or the correction means, and outputs the remaining color image signals to the plurality of image forming sections.

〔Example〕

FIG. 1 is a process 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 section, which processes cyan signals (C signals), green signals (G signals), and yellow signals (Y signals) that are sequentially output from one chip of the color image sensor 56 for each pixel.

Create a B (C-G) signal and an R (Y-G) 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 Tsunagi memory, analog processing section 1
The processed digital signals are synthesized and spliced into a five-channel video signal within the horizontal synchronization signal section. Reference numeral 3 denotes an image processor unit (IPU) that performs shading correction processing for correcting the light distribution of the video signal sent from the trunk memory 2, and masking processing for correcting color tint. After completing each process, the IPU 3 converts it into an image signal VIDEO of 8 beats 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. 6 is the operation section,
Enter various image processing modes.

The multiple unit 7 has a control unit 8. The control unit 8 is composed of a synchronization control section 97 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.
If TOPA precedes the image writing permission signal IToPB, the image reading start signal R3TART is sent to the color reader 5 in synchronization with the 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 PB is received is counted by the horizontal synchronization signal RHSYNC generated by the color reader 51, and the image signal is written in the multiple 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 writing permission signal TOFB, the above description is reversed and the image writing permission signal ITO
When PA and image write permission signal ITOPB are applied at the same time, one image value number VIDEO is generated in synchronization with image write permission signal ITOPA or image write permission signal ITOPB.
is written to the synchronous memories 11b and 12b.

12c is a synchronization control unit that controls the color printer 11.
The horizontal synchronizing signal PH5YNC for 12 and the clock PCLK for image transport are generated, and the synchronous memory llb, 1
The gradation control circuit 11d reads out the image signal VIDEO stored in the gradation control circuit 2b.

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 11e and 12e before writing an image, and controls the BD double signal control units 11g and 12.
Output to g. 137.13m, 13c, 13
bk is a toner detection sensor that detects the presence or absence of each developer in the color printer 11.

14y, 14m, 14c, and 14bk detect the presence or absence of each developer in the color printer 12.

FIG. 2 is a block diagram illustrating the configuration of the control unit 8 shown in FIG.
Image writing permission signals ITOPA, ITO are sent from the ITOP sensors 11a, 12a of the color printer 11.12 in response to the horizontal synchronization signal RH3YNC sent from the
It latches PB and outputs latch pulses LA and LB to the subsequent latches 22a and 22b. 23 is a counter which receives the horizontal synchronization signal RHSYN which is also sent out from the synchronization signal processing section 4.
Count C and latch 22a.

A count signal is output to 22'b. 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 U31.

That is, the -comparison output CA is output when the image write permission signal ITOPA is output before the image write permission signal ■TOPB, and the other comparison outputs CB and CC become rQJ. Also, comparator output CB
is output when the image write permission signal ITOPB is output before the image write permission signal ITOPA,
Other comparator outputs CA and CC become rQJ. Furthermore, the comparator output CC1 image write permission signal I
It is output when TOPA and image write permission signal ITOPB are output at the same time, and multiple comparison outputs CA
, CB becomes "0". 25a, 25b are bar/7
7, the outputs of latches 22a and 22b and their inverted outputs are held. 26 is an adder, buffers 25a, 25
The relative difference of b is calculated and an added value signal ADDE 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.

FIG. 3(a) is a block diagram illustrating the transmission control operation of the image data VIDEO stored in the multiplexed memory 0 shown in FIG. 1, and the same parts as in FIG. are doing.

In this figure, numeral 31 denotes a CPU serving as data control means of the present invention, which is provided in the control unit 8 and outputs comparator outputs CA, CB, CC and addition value signals ADDE,
receive. 41a, 41b.

42 is a gate circuit with comparator outputs CA, CB, and C.
Image signal VID stored in the multiple memory 1o according to G
A gate circuit 43.4 gates the direct image signal VIDEO sent out from the EO or IPU3, and
A video signal VIDEO is output to 4. Gate circuit 43
．． 44 is the comparator output CA, CB from the CPU 31.
, CC, the control signals a and b are output, and the image signal VIDEO or the control signal P stored in the multiple memory 10 is output.
Synchronous memory 11b, i2b of color printer 11.12 for direct image signal VIDEO sent from U3
a45 to control the output to the color mode signal according to the color mode signal.
a + 45 b is an AND gate, which is an image reading start signal 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 printer 11.12. Masks the transmission of R3TART. Control signals c and d for masking the transmission of the image reading start signal R5TART are output from the CPU 31 to one end of the /node gate 45a and 45b.
The outputs of a, 4' and 5b 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 the same parts as in FIG.

In this figure, ADCOT is an address control unit, and L of an n-stage line buffer memory that constitutes a single-layer memory 10
BMI to LBMN as the first image writing permission signal I
The line determined by the difference between TOPA and image write permission signal ITOPB, that is, horizontal synchronization signal RH5YN
The LBM of the line buffer memory for a predetermined line is calculated according to the difference between the first image write permission signal ITOPA and the image write permission signal ITOPB after counting at C.
Allow I-LBMN to be selected. VICOT is an image control unit that counts the horizontal synchronization signal RH3YNC and outputs the IPU3
The image signal VIDEO sent from the address control unit A
LBMI of line buffer memory selected by DCOT~
Write to LBMN. Note that the address control unit ADCOT
secures a memory area for n+1 (1<n+1<N) lines when the number of lines of difference 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 on the operation section 6, an operation command is sent from the control unit 5 of the color league 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 'I T
In order not to output the OP A and the image writing permission signal ITOFB to the color reader 51, the CP shown in FIG.
Control signals c and d from U31 are sent to AND gates 45a and 45
Output to +. On the other hand, ITOP sensors 11a and 12a
The first image writing permission signal ITO output from
PA and image write permission signal ITOPB are also output to latches 21a and 21b shown in FIG. latch 21a,
21b is the first image writing permission signal ITOPA.
A horizontal synchronizing signal RH5YNC generated by the synchronizing signal processing section 4 of the color reader 51 is input to the clock terminal CK before the image writing permission signal ITOPB is sent. When the latches 21a and 21b receive the first image write permission signal ITOPA and the image write permission signal ITOPB, they output latch pulses LA and LB to the subsequent latches 22a and 22b. While the horizontal synchronizing signal RH3YNC is being sent to the latches 22a and 22b, the counter 2
A count signal is sent from 3, and the count value counted up to that point is output to the comparator 24 in synchronization with the latch pulses LA and LB. In response to this, the comparator 24 compares the respective count values,
It is determined whether the image write permission signal ITOPA and the image write permission signal ITOPB are sequential or simultaneous, and the image write permission signal ITOPA is set as the image write permission signal ITOPB.
If it is output earlier than the comparator output CA
is output to the CPU 31 and also to the buffer 25a. On the other hand, the buffer 25tl has a latch 22b.
Based on this, the adder 26 sends the calculated value signals ADDE and ADDD, which are the difference, to the CPU 31.
and output to the synchronization control section 9. In response to this, the address control unit ADCOT of the synchronization control unit 9
A predetermined line portion of the line buffer memories LBM1 to LBMN is reserved for storing the image signal VIDEO. Next, the control unit 8 outputs a second image writing permission signal for starting image reading, that is, a preceding image writing permission signal ITOPA, to the color reader 51 at a predetermined timing. As a result, the color reader 51 turns on the exposure lamp 57 and starts scanning the document scanning unit 54, and the reflected light is color-separated by the color image sensor 56, and the horizontal synchronization signal RHSYN is
The image signal VIDEO is processed by the IFU 3 in synchronization with C, and the processed image signal VIDEO is directly sent to the preceding color printer 11 line by line to the synchronous memory 11b via the multiplex unit 7. 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 ADCO
T is the line buffer memory LBMI in the multiple memory 10
- Since a memory area for LBM4 (the number of lines + 1 line) is secured, the image signal VIDEO of each line sent out in synchronization with the horizontal synchronization signal RH3YNC is stored in the line buffer memories LBM1 to LBM4', for example, to the line buffer. Memory LBM4, LBM3, LBM2
When the next horizontal synchronizing signal RH3YNC is input, the image signal V I DEO1 for one line written in the line buffer memory LBM4 is read out.
In parallel with this reading, line buffer memories I and B are
Writes the fourth line of image signal VIDEO4 to MI, then reads one line of image signal VIDEO2 written to line buffer memory LBM3,
In parallel with this reading, the line buffer memory LBM
The operation of writing the image signal VIDEO5 of the fifth line to S'y RH5YNC is sequentially performed in synchronization with the Mizuno synchronization signal S'y RH5YNC. The image signals VIDEO written to line 7' buffer memories LBM1 to N 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. 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 by the operation unit 6 + one image writing permission signal ITOPA and the image writing permission signal ITOPB are outputted by the AND gate 45a,
45b, the preceding image writing permission signal IT
Image reading is performed in synchronization with OPA, and the image signal VIDEO for each line is sent to the color printer 11 as described above.
゜12. Note that the image signal VIDEO is sent to the synchronous memory 11b of the color printer 11.12.

12b, the horizontal synchronization signal P generated by the synchronization control units 11c and 12c in the color printers 11 and 12
The processing speed is converted by the clock signal PCLK for conveying H3YNC and the image signal VIDEO.

Next, the operation of the control units 5, 8, 11g and 12g shown in FIG. 1 will be explained with reference to FIGS. 4 to 6.

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 511 multi-unit unit 7, color printer 11.1
The system waits until the start of startup is OK (2), and when the start of startup is OK, the system waits for the print key (not shown) on the operation unit 6 to be pressed (3), and when it is pressed, the control unit 5 Control unit 8 of unit 7. Send the Briscan operation command via the control units 11g and 12g of the color reader 11.12 4), the control unit 11g
, 12g sends a drive start signal to the rotation drive system of the transfer drum to start pre-rotation. As a result, the ITOP sensor lla, 12a sends the image writing permission signal 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 difficult to judge whether it has been output or not.8)
, if NO, return to step (4); 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
Execute the sequence according to the color mode 8), judge whether the color mode sequence is finished 9), if No, return to step (8), if YES, step (2)
).

FIG. 5 is a flowchart illustrating the operation of the control unit 8 of the multiple unit 5 shown in FIG. wS1. In addition,(
1) to (9) indicate each step.

First, execute the initial display routine 1), color reader 511 multi-unit 7, color printer 11.
2) , , N
If YES, the error processing routine will be executed (3), and if YES, the system will wait for the print key (not shown) on the operation unit 6 to be pressed (4), and when it is pressed, the first image writing permission signals ITOPA and ITOPB will be activated. color reader 51
AND gates 45a, 45b so that the
(5). Next, it is determined whether the calculated number of differential lines exceeds the line buffer memory number of the multiplexed memory 1o, that is, LBMN, and is in a full state8).
If YES, the color printer 11.12 sends a command to move the output position of the image writing permission signals ITOPA and ITOPB output from the color printer 11.12.
7), return to step (2), and if No, output the second image writing permission signal, for example, the preceding image writing permission signal ITOP.
The gate circuit 43 outputs the image signal VIDEO corresponding to the color mode to the color printer 11 or the color printer 12 while outputting the image signal A to the color reader 51.
．． Turn on 44 (8). Next, gate circuit 43.
Determine whether or not the specification of 44 has been completed (9). If no, return to step (8); if YES, proceed to step (4).
Return to

FIG. 6 is a flowchart for explaining the operation of the control units I1g and 12g of the color printers 11 and 12 shown in FIG. Note that (1) to (12) 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, Toner remaining amount detection sensor 13y provided in each color printer 11.12
, 13m, 13c.

13bk, 1”41, 14m, 14c,
14bk output is checked for toner absence, and the developed color that cannot be formed by each color printer 11.12 is stored in the control unit 11a, 12a (7) internal memory (RAM) (4) 0 Then, the color is stored in the internal memory. Determine whether a color image signal is being sent by the developer material5.
), if YES, the CPU 31 serving as data control means limits the transmission of the color image signal (8).

On the other hand, if the judgment in step (5) is NO, the system waits for the print key to be pressed (7), and when the print key is pressed, the pre-rotation process is executed (8), and the image writing permission signal is sent as described above. ITOPA and ITOPB are sent to the v control unit 8 of the multiple unit 7. Next, the output position of the image write permission signals I TOPA and ITOPB, which are output when the number of differential lines between the image write permission signals I TOPA and I TOPB exceeds the maximum line number of the line buffer memory of the multiplexed memory 1o, is moved. 9)
, if YES, move each transfer drum to the output position (10) and return to step (7); if NO, execute color mode designation process 11), and check whether image formation based on the color mode designation process has been completed. 12)
, if No, return to step (11); if YES, return to step (2). In addition, color printer 11.12
In this case, system efficiency can be greatly improved by allowing image formation to continue using formable color toners unless all color toners are present.

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.

In this figure, VSYNCA and VSYNCB indicate vertical synchronization signals, and VIDEOA and VIDEOB indicate image signals. This shows the state in which the image 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 signals ITOPA and ITOPB are measured.
, 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 differential line measurement control is interrupted and the differential line is corrected again, the accuracy of preventing image shift can be further improved.

Further, although the above embodiments have been described using a color printer as an example, the present invention can be easily applied to an image forming apparatus that performs multiple transfer by wrapping transfer paper.

Furthermore, the above embodiment is a color printer 1].

12, the image signal VI D read by the color reader 5]
Although the case where EO is sent out has been described, up to N printers can be connected, and when N printers are connected, N+1 multiple units 7 may be provided.

〔Effect of the invention〕

As described above, the present invention includes a determining means for determining the destination of image writing permission signals sequentially outputted from each image forming section, and a determining means for determining which image writing permission signal is outputted after receiving the first image writing signal outputted to the determining means. A measuring means for measuring the output interval of the image writing permission signal determined by the determining means, and correcting the transfer timing of the color image signal read by the image reading section to the delayed image forming section in synchronization with the preceding image writing permission signal determined by the determining means. out of the color image signal sent from the correction means and the color image signal read by the image reading section, any color image signal is erased, and the remaining color image signal is used to form an image. Since the printer is equipped with a data control means for transmitting data to the printer, the magenta, cyan, yellow signals and the black signal in the color image signal can be sent to different printers, allowing image formation specific to the color mode. . Furthermore, since image formation can be continued unless all of the color toners of each printer are present, this method has excellent advantages such as greatly improving the image forming efficiency of the printer.

[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, 10 is a multiple unit memory, 11.12 is a color printer, lla, 12
a is an ITOP sensor, llb, 12b is a synchronous memory, 1
1c and 12C are synchronization control units, 11f and i2f are BD-t
'7s, 11g, and 12g are control units, and 51 is a color reader. Figure 3 (a) Figure 3 (b) Figure 4 Figure 5 S6 Figure 7 IDEOB

Claims (4)

[Claims] (1) In an image forming apparatus consisting of an image reading unit that converts a color image into an electrical signal and reads it, and a plurality of image forming units that write the color image signals read by this image reading unit, a determining means for determining the output of the image writing permission signal; a measuring means for measuring the output interval of the image writing permission signal outputted after receiving the first image writing permission signal outputted to the determining means; a correction means for correcting the transfer timing of a color image signal read by the image reading section to a delayed image forming section in synchronization with the preceding image writing permission signal discriminated by the discrimination means; and a color output from the correction means. An image comprising a data control means for erasing an arbitrary color image signal among the image signal and the color image signal read by the image reading section and transmitting the remaining color image signal to an image forming section. Forming device. (2) The image forming apparatus according to claim (1), wherein N-1 correction means are provided for N image forming units. (3) 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. (4) The data control means outputs only formable color image signals to the image forming section from among the color image signals output from the image reading section based on the residual developing material information output from the image forming section. Claim No. 1 (1) characterized by
).