JP2005059408A - Image formation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To raise expandability of a use of a printer controller in which a plurality of lines of images are simultaneously transferred in parallel to a printer. <P>SOLUTION: An image forming device includes the printer PTR for performing image writing based on data of each line by one or more a-pieces of writing means 31y by receiving data of a plurality of lines simultaneously by generating a control signal XWRSYNC Y for transferring the image based on a synchronizing signal DEPT Y of a line writing period; and a printer controller 100 for transferring to the printer simultaneously in parallel with data XIPUDAT Y1, XIPUDAT Y2 of a plurality of b (the b is a or more) of lines. When the a is less than the b, the printer generates a control signal XWRSYNC Y in a period of b/a times as large as a synchronizing signal DEPT Y, gives to the printer controller, and writes each one line by each writing means 31y during one period of the synchronizing signal DEPT Y based on image data of b-line received from the printer controller. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus that realizes surface recording by repeating line scanning. In particular, although not intended to be limited to this, an electrostatic latent image is formed on a photosensitive member by optical writing using laser scanning on the photosensitive member. The present invention also relates to a laser exposure electrophotographic image forming apparatus that develops and transfers the electrostatic latent image onto a sheet. The image forming apparatus of the present invention is used in, for example, a printer, a copying machine, or a facsimile machine.

  For example, a copying machine or a facsimile apparatus using a laser printer which is an electrophotographic image forming apparatus of laser exposure is a system controller for writing to an image memory and image data to the laser printer and reading the image data to the laser printer in addition to the laser printer Alternatively, a printer controller (sometimes referred to as a copy application board, a printer application board, or a facsimile application board) is provided. The laser printer for single color (white / black) recording uses a laser beam generated by one laser diode (LD) on the surface of the photoconductor with a polygon mirror, and the width direction (main scanning direction; in the case of a photoconductor drum, the rotation axis is In the meantime, the laser diode driving current is modulated (including ON / OFF) with the image data.

  A laser sensor is located outside the effective scanning (image forming) area in the main scanning direction of the laser reflected from the polygon mirror. The laser printer is based on the laser detection signal (pulse) generated by this sensor. Generates a line synchronization signal for defining the starting point of each main scanning line, generates a control signal for requesting transfer of image data addressed to each line based on the line synchronizing signal, and supplies the control signal to the printer controller. In addition to receiving image data, the image data is LD corresponding to the laser scanning position (main scanning position = pixel position on one line, sub-scanning position = line position on one page (frame)) based on the line synchronization signal and the pixel clock. Output to the driver (modulation drive circuit). The printer controller transfers image data for one line from the image memory to the printer for each laser scanning by the polygon mirror, that is, for each main scanning line. That is, one line of image data is output to the printer per one cycle of the line synchronization signal.

  In the case of a typical color laser printer, for example, as shown in FIG. 2, four sets of imagers mainly composed of a photosensitive member 6 and a developing unit 7 are arranged in tandem along the moving direction of the transfer belt 10. Lasers are individually emitted from four LDs for each recording color (yellow Y, magenta M, cyan C, and black K), reflected by a polygon mirror, and scanned and projected onto each photoconductor. Each color toner image formed on each photoconductor is transferred onto a sheet of paper.

  Recently, the use of general-purpose buses for image data transfer has increased, and the parallel transfer capability (the number of bits of the bus) that can be used for image data transfer has also increased. In order to increase the optical writing speed, one-color multi-laser scanning using a plurality of LDs for laser scanning for image formation of one color has also been proposed.

Japanese Patent Application Laid-Open No. 8-149241 describes that an image forming apparatus and its peripheral devices are connected by a general-purpose bus of a system controller to easily realize system expansion.

In Japanese Patent Laid-Open No. 11-220574, even if one-color multi-laser scanning is adopted, image data is transferred for one line per one-line scanning (one cycle of laser scanning synchronization signal) by a polygon mirror. In the case of control, since the image data transfer bus needs to be expanded, in order to avoid this, a pseudo line synchronization signal is generated during one cycle of the synchronization signal of laser scanning, and the image data is synchronized with this. An image forming apparatus that multiplies the transfer amount of image data during one period of a synchronization signal of laser scanning by performing transfer is proposed.

In Japanese Patent Laid-Open No. 2002-127498, the print pixel density (dpi) has become diverse, such as 1200, 600, 400, 300, 200, and the like. A method of doubling by using a line memory or the like for the difference between the pixel density and the writing density is 1200 dpi, which is the least common multiple of the pixel density. As the / F becomes complicated, a control signal based on the main scanning line trigger signal is sent from the printer to the application board, and the application board presents an image forming apparatus that transfers image data to the printer according to the control signal. .

  Multi-writing that enables use of general-purpose bus or bus with multi-bit simultaneous transfer capability for image data transfer, and writing of multiple lines during one period of one-line scanning synchronization signal for one-color image formation However, the consistency of the combination of the image data transfer capability of the image data transfer bus and the write capability of how many lines are written during one period of the synchronization signal for one line scanning for one-color image formation is low. . For example, the printer controller has a specification that simultaneously transfers two lines of 8-bit image data addressed to one pixel on a parallel 16-bit bus, and two laser printers for one-color image formation. In case of multi-writing that uses LD to write two lines at the same time, 8 bits addressed to one pixel from the printer controller in parallel with the synchronization signal of one line scan via a parallel 16-bit bus. Two lines of the image data of the configuration can be transferred simultaneously in parallel, and two lines can be written simultaneously by two LDs, thereby forming an image at high speed. However, this printer controller cannot be applied to a laser printer having one LD for one-color image formation.

  An object of the present invention is to enhance the expandability of the use of a printer controller that simultaneously transfers a plurality of lines of image data in parallel.

(1) Generate a control signal (XWRSYNC Y) for image data transfer based on a synchronization signal (DETP Y) generated in the line writing cycle, and simultaneously receive a plurality of lines of image data. In response to the control signal (XWRSYNC Y), a plurality of lines b and b are a or more lines of image data (XIPUDAT Y1) in response to the control signal (XWRSYNC Y). , XIPUDAT Y2) simultaneously and in parallel to the printer (PTR), a printer controller (100);
When the a is less than b, the printer (PTR) generates the control signal (XWRSYNC Y) at a cycle of b / a times the synchronization signal (DETP Y) and gives it to the printer controller (100). One line is written by each writing means during one period of the synchronization signal (DETP Y) based on the b-line image data received from the printer controller (100). Forming equipment.

  In addition, in order to make an understanding easy, the code | symbol of the corresponding element or the corresponding matter of the Example shown in drawing and mentioned later in parentheses is added for reference for the illustration. The same applies to the following.

  Conventionally, in a copy application by a printer controller, in order to execute image processing such as filter processing (MTF correction processing, smoothing processing) at high speed on image information read by a scanner, a printer write controller (111) When two identical circuits are provided and image processing is performed simultaneously, image information for odd lines and image information for even lines are output simultaneously, and then an image transfer rate conversion memory is used and the image read frequency is set to 2 of the write frequency. The two-line parallel image information is converted into one-line serial image information and transferred to the image forming apparatus. According to this embodiment, the printer (PTR) is a semiconductor laser (writing means) 31y), when the number of used a is less than the number of lines b for simultaneous and parallel transfer, the control signal (XWRSYNC Y) is generated at a cycle of b / a times the synchronizing signal (DETP Y) and printed. 1 line is written by each semiconductor laser (31y) during one period of the synchronization signal (DETP Y) based on the b line image data received from the printer controller (100) and received from the printer controller (100). Do. Therefore, in the printer controller (100), the existing control of the writing controller (111) can be performed without changing the transfer control for simultaneously transferring the image data of a plurality of lines in parallel, and thus without unnecessary image memory. Image information can be exchanged at low cost using a memory.

  (2) Even when a = b, the printer (PTR) generates the control signal (XWRSYNC Y) at a cycle of b / a times the synchronization signal (DETP Y) to generate the printer controller (100 ) And writing data for each line by each writing means during one period of the synchronization signal (DETP Y) based on the b-line image data received from the printer controller (100); The image forming apparatus according to 1). In this case, there are a plurality of semiconductor lasers (31y) as writing means, and each line is written using each line of a plurality of lines of image data transferred in parallel. The image forming speed is increased.

  (3) The printer (PTR) includes an exposure unit that scans and exposes the photosensitive member using one photosensitive member (6a), a semiconductor laser (31y), and a writing controller (111) that drives to emit light. (5), a synchronization detection means (38ym) for detecting the synchronization of the exposure means, and the control signal at a period of b / a times the period based on the synchronization detection signal (DETP Y) from the synchronization detection means A laser exposure electrophotographic printer having control signal generation means (102) that generates (XWRSYNC Y) and supplies the generated signal to the printer controller (100); image formation according to (1) or (2) above apparatus.

  (4) a is plural, and the synchronization detection means (38ym) detects a scanning exposure laser generated by the a number of semiconductor lasers (31y); the printer (PTR) further includes the synchronization detection means The image forming apparatus according to (3), further comprising: synchronization separation means (107) that generates a synchronization detection signal addressed to each laser based on the detection signals of the a scanning exposure lasers generated by (38ym).

  (5) A plurality of one-color image forming mechanisms including the photoconductor (6a) and the image forming mechanism are provided for different color image formation, and each color image formed by each image forming mechanism is provided on one sheet of paper. The color image forming apparatus according to any one of the above (1) to (4), further comprising means (10, 11) for superimposing and transferring to the image.

  (6) an image pickup means (300) for taking an image and generating image data representing the image; and the printer controller (100) is an image memory for storing image data generated by the image pickup means (300) ( 116), and transfers the image data of the image memory (116) to the printer (PTR); The image forming apparatus according to any one of (1) to (5).

(7) a photosensitive member (6a), one or more semiconductor lasers (31y) and a writing controller (111) for driving the light emitting device to expose and expose the photosensitive member (5); Based on synchronization detection means (38ym) for detecting synchronization, printer controller (100), and synchronization detection signal (DETP Y) from the synchronization detection means, image information from the printer controller (100) is obtained at a predetermined timing. Transfer trigger signal generating means (102) for generating a main scanning line trigger signal (XRWSYNC Y) and a sub-scanning effective area trigger signal (XFSINC Y) for transfer to the writing controller (111), and the printer The controller (100) at least receives the main scan line sync signal (XIPUSYNC Y) from the main scan line trigger signal (XRWSYNC Y), and the sub scan valid area signal (XIPUFGT Y) from the sub scan valid area trigger signal (XFSINC Y) Generate image information in sync with these In an image forming apparatus for transferring information (IPUDAT Y) to the exposure means (5),
When it is necessary to transfer multiple lines of image information (IPUDAT Y1, IPUDAT Y2) simultaneously due to the internal processing of the printer controller (100), the semiconductor laser (31y) used in the exposure means (5) The main scanning line trigger signal (XRWSYNC Y) cycle is included in one cycle of the main scanning line trigger signal (XRWSYNC Y) based on the number of used and synchronization detection signal (DETP Y) cycles. An image characterized in that the number of transfer lines of image information is variable so as to be equal to a number obtained by multiplying the number of periods of the synchronization detection signal (DETP Y) within the one period by the number of semiconductor lasers (31y) used. Forming equipment.

  In order to execute image processing such as filter processing (MTF correction processing, smoothing processing) at high speed on image information read by a scanner with a conventional copy application, the write controller (111) has two identical circuits. When performing image processing at the same time, after simultaneously outputting the image information of the odd lines and the image information of the even lines, an image transfer speed conversion memory is used and the image read frequency is set to twice the write frequency. The information is converted into one-line serial image information and transferred to the image forming apparatus. According to this embodiment, the main scanning line trigger signal (XRWSYNC Y) is included in one cycle of the synchronization detection signal ( DETP Y) and the number of used semiconductor lasers (31y) used in the exposure means (5) to be equal to the number multiplied. Affection Information transfer (IPUDAT Y1, IPUDAT Y2) at the same time without changing the transfer control, and therefore without the need for unnecessary image memory, and using the existing memory of the write controller (111) to transfer image information at low cost Can be done.

  FIG. 1 shows the appearance of a multi-function full-color digital copying machine according to an embodiment of the present invention. This full-color copying machine is roughly constituted by units of an automatic document feeder (ADF) 400, an operation board 610, a color scanner 300, a color printer PTR, and a paper feed table 200. A LAN (Local Area Network) connected to a personal computer PC is connected to a system controller (not shown) in the machine. The system controller of the copying machine can be connected to a communication network (Internet), and can exchange data by communicating with a management server of a management center (not shown) via the communication network. A facsimile controller FCU (not shown) in the machine can perform facsimile communication via the exchange PBX and the public communication network PN.

  FIG. 2 shows an image forming mechanism of the color printer PTR shown in FIG. In the figure, photosensitive drums 6a to 6d that form images of different colors (yellow: Y / y, magenta: M / m, cyan: C / c, black: K / bk) convey transfer paper 8. Are arranged in a line along the conveyor belt 10. In accordance with the image signal for recording, the exposure device 5 is placed on the photosensitive drums 6a, 6b, 6c and 6d for Y, M, C, and K recording, which are uniformly charged by the charging charger. Then, a laser beam modulated by an image signal for K recording is scanned and projected to form an electrostatic latent image. Each electrostatic latent image is developed with each of Y, M, C, and K toners by the developing devices 7a, 7b, 7c, and 7d to form toner images (visualized images: visible images) of the respective colors.

  On the other hand, the transfer paper is conveyed from the paper feed cassette 8 onto the transfer belt 10 of the transfer belt unit, and each color image (developed image) developed and formed on each photosensitive drum is transferred to the transfer units 11a, 11b, 11c and 11d. Are sequentially transferred onto the transfer paper, and after being superimposed, are fixed by the fixing device 12. After the fixing, the transfer paper is discharged out of the machine.

  The transfer belt 10 is a translucent endless belt supported by a drive roller 9, a tension roller 13a, and a driven roller 13b, and the tension roller 13a pushes down the belt 10 with a spring (not shown). The tension of the belt 10 is substantially constant.

  FIG. 3 is a plan view of the optical unit constituting the exposure unit 5 in FIG. 2 as viewed from above. In the figure, light beams from a laser diode unit (LD unit) 31bk and an LD unit 31y including a laser diode and a laser driver that modulates the laser light pass through cylinder lenses 32bk and 32y, and are reflected by a reflecting mirror 33bk and a reflecting mirror 33y. Is incident on the lower surface of the polygon mirror 34, and the polygon mirror 34 rotates to deflect the light beam, pass through the fθ lens 35bkc and the fθ lens 35ym, and are folded back by the first mirror 36bk and the first mirror 36y.

  On the other hand, the light beams from the LD unit 31c and the LD unit 31m pass through the cylinder lenses 32c and 32m, enter the upper surface of the polygon mirror 34, and the polygon mirror 34 rotates to deflect the light beam, and the fθ lens. The light passes through 35bkc and the fθ lens 35ym and is folded back by the first mirror 36c and the first mirror 36m.

  Cylinder mirrors 37bkc and 37ym and sensors 38bkc and 38ym are provided upstream from the writing position in the main scanning direction, and the light beam that has passed through the fθ lenses 35bkc and 30ym is reflected and collected by the cylinder mirrors 37bkc and 37ym, It is configured to be incident on the sensors 38bkc and 38ym. These sensors 38bkc and 38ym are synchronization detection sensors for synchronizing in the main scanning direction.

  In the detection of light beams from the LD units 31bk and 31c, a common sensor 38bkc is used on the writing side. Similarly, for the detection of light beams from the LD units 31y and 31m, a common sensor 38ym is used on the writing side. Since two color imaging light beams are incident on the same sensor, the timing at which each light beam is incident on each sensor can be set by making the incident angles of the polygon mirrors 34 different from each other. Instead, it is output as a pulse train in time series. As can be seen from the figure, K (bk) and C (c) and Y (y) and M (m) are scanned in the opposite directions. Regarding the method of separating the output from the synchronous detection sensor common to the two colors into the respective color components, various methods have been announced so far, and will not be described in the description of this embodiment.

  FIG. 4 shows a block diagram of a control circuit of the printer PTR shown in FIG. In the figure, a copy application (copy application) 115 temporarily stores the image data obtained from the document scanner 300 in the image memory 116 and reads the timing read from the image memory 116 for each color by the timing Y generation circuit 102 and the timing M generation. The timing is determined based on timing signals generated by the circuit 103, the timing C generation circuit 104, and the timing K generation circuit 105. The printer controller 100 includes a printer application and a facsimile application. Image data sent from the outside is also stored in the image memory 116 and then read out and printed by the printer PTR. Print data (character information) given from an external PC (personal computer) is developed into image data by the printer controller 100 and stored in the image memory 116, and then read out and printed by the printer PTR.

  The synchronization separation (Y) 107 and the synchronization separation (M) 108 shown in FIG. 4 separate and generate a laser exposure synchronization signal (scan line base point signal) addressed to each color y and m from the output of the sensor 38ym of FIG. Similarly, the synchronization separation (C) 109 and the synchronization separation (K) 110 are circuits that separate and generate each synchronization signal from the output of the sensor 38bkc.

  An LD unit 31y is connected to a laser diode control board (hereinafter referred to as LDB (Y)) 111 which is a writing controller. Similarly, an LD unit 31m is connected to an LDB (M) 112 and an LDB (C). The LD unit 31c is connected to 113, and the LD unit 31bk is connected to the LDB (K) 114.

  Next, a description will be given with reference to the timing chart shown in FIG. Sync detection signal (hereinafter referred to as DETP) Y from sync separation (Y) 107, DETP M from sync separation (M) 108, DETP C from sync separation (C) 109, and DETP K from sync separation (K) 110 are output Is done. DETP Y, DETP M, DETP C, and DETP K are relatively asynchronous signals. This is because the same mirror surface is not used on the Y, M side and the C, K side, and the position of the LD light emitted from each LD unit 31y, m, cbk is different. However, the period indicated by X in FIG. 5 includes a period in which the assert edge of each DETP does not come, and can be derived from the component accuracy of the optical system.

  The LDB (Y) 111 in FIG. 4 outputs a signal DPSYNC Y synchronized with the write clock of the Y LD from the DETP Y to the reference selection circuit 106. Similarly, LDB (M) 112 outputs DPSYNC M, LDB (C) 113 outputs DPSYNC C, and LDB (K) 114 outputs DPSYNC K. The reference selection circuit 106 arbitrarily selects DPSYNC of Y, M, C, and K, and generates CNT LD (reference signal) in an arbitrary period of the DPSYNC. The timing Y generation circuit 102 delays the XSTART output from the registration sensor 101 to CNT LD, counts with DPSYNC Y for the number of lines set to PFGDY Y, asserts the frame synchronization signal XFSYNC Y, and outputs the image data transfer synchronization signal XWRSYNC. Along with Y, it is transferred to the copy application 115. Similarly, the other XFSYNC M is asserted by counting with the number of set lines DPCNT M from CNT LD to PFGDLY M, XFSYNC C is DPSYNC C with the number of set lines from CNT LD to PFGDY C, and XFSYNC K is CNT DPSYNC K is asserted for each set number of lines from LD to PFGDYLY K, and transferred to the copy application 115 together with XWRSYNC M, XWRSYNC C, and XWRSYNC K.

  The copy application 115 generates the image data transfer frame gate signal XIPUFGT shown in FIG. 6 from the XFSYNC for each color, and generates the line synchronization signal XIPULSYNC for the image data transfer from XWRSYNC. In synchronism with this, the image data IPUDAT is read from the image memory 116 and returned to the LDBs 111 to 114 corresponding to the respective colors, and the LDBs 111 to 114 expose the photoconductors 6a to 6d based on the image information from the copy application 115. . The timing is shown in FIG. The exposure period of each line is shown by hatching.

  Further, the copy application 115 performs various image processing on the normal document image. For example, in the case of a character original, MTF correction processing (resolution improvement) is performed to enhance the amplitude of the read image on the image read by the scanner 300, and on the contrary, the amplitude of the read image is smoothed for the photo original. Although smoothing processing (moire reduction) is generally used well, recent image processing has become complicated, and the number of cases where computation processing takes time has increased. As a countermeasure, in order to execute complex calculations at high speed, it has a plurality of circuits for performing digital filter calculations, and outputs image information for a plurality of lines in the sub-scanning direction at the same time, and the printer PTR has one line of image information. Since it can only be received, there is an increasing number of cases where the image memory is used to make one line and output to the printer PTR. In the first place, the printer has an image memory for converting an image, for example, an actual LD lighting frequency, and an image memory for performing pattern matching for performing a smoothing process for a plurality of lines. This is only due to the I / F specifications of the copy application 115 and the printer PTR, and requires an extra image memory.

  In the first embodiment of the present invention for solving this problem, each of the LDBs 111 to 114 is equipped with one LD, and each of the LDBs 111 to 114 has two circuits for performing digital filter operation, and is a copy. The application 115 outputs image data for two lines to the printer PTR (111 to 114) in the sub-scanning direction at the same time. An example of this is shown in FIG. For convenience of explanation, only the Y color timing is shown, but the explanation is omitted because the image data is transferred in the same manner for the other M, C, and K colors.

  In the first embodiment of the present invention, the copy application 115 asserts XIPUFGT Y in response to XWRSYNC Y immediately after XFSYNC Y is input from the LDB (Y) 111, but at this timing, the timing Y generation circuit 102 The XWRSYNC Y cycle is twice as long as DETP Y, which is the synchronization signal of one line of laser scanning (decimation), and IPUDAT Y1 and IPUDAT Y2 are transferred to the LDB (Y) 111 in one cycle of XIPUSYNC Y. The image memory for making one line on the copy application 115 side can be omitted.

  The LDB (Y) 111 uses an internal image memory for converting to an actual LD lighting frequency and an image memory for performing pattern matching for performing smoothing processing, and IPUDAT Y2 is delayed to the next DETP Y by line delay. As a final IPUDAT Y line, the light emission modulation of the semiconductor laser 31y is performed based on the IPUDY Y. The image memory configuration of the LDB (Y) 111 and the writing and reading of image data to and from the memory are output to the light emission modulator for one line (preceding line) of the two lines of image data transferred in parallel. And writing another line (following line) to the image memory, reading the image data for the succeeding line from the image memory triggered by the next generated DETP Y, and outputting to the light emitting modulator Then, two lines of image data are transferred (received) in parallel with the next generated DETP Y as a trigger.

  Next, two LDs are mounted on each of the LDBs 111 to 114, and there are two circuits for performing digital filter operation. The copy application 115 transfers image data for two lines in the sub-scanning direction to the printer PTR at the same time. An example of the second embodiment of the present invention is shown in FIG.

  The second embodiment of the present invention is different from the first embodiment using one LD in that two LD lasers hit the sensor 38ym only for y writing, and therefore one cycle of the synchronization detection signal DETP Y. There are two “L” periods (DETP Y in FIG. 8), and the rotation speed is adjusted so that image information for two lines can be printed by one rotation of the polygon mirror. Conventionally, since one line of image information is required for one XWRSYNC Y cycle, the relationship between the cycle of XWRSYNC Y and DETP Y can be changed to 2: 1, and image information is used using an image memory. Must be serialized into two lines.

  On the other hand, in the second embodiment of the present invention, the printer PTR transfers image information for two lines in one cycle of XWRSYNC Y. Therefore, the periods of DETP Y and XWRSYNC Y are the same (no thinning is performed). If the image information for two lines is transferred in one cycle of XWRSYNCY, the writing condition for one line is the same as when one LDB LD is mounted. Here, when the IPUDAT is transferred in 8-bit parallel, the image information input unit of the LDBs 111 to 114 needs to receive image information for two lines at the same time in the present invention, so a 16-bit input unit is required.

  In the second embodiment, in the printing mode in which each LDB 111 to 114 performs optical writing with only one semiconductor laser, the LDBs 111 to 114 are switched to the above-described functions of the first embodiment. Also, if there is an LDB in which one of the two semiconductor lasers or one of the laser drivers is defective in the LDBs 111 to 114, in the printing mode using the LDB, another normal LDB is also one semiconductor. It is switched to the aforementioned function of the first embodiment, in which only the laser is used for optical writing. Therefore, in the second embodiment, it is possible to selectively perform the high-speed and low-speed printing modes by always utilizing the parallel simultaneous transfer function of the two lines of the printer controller 100, or of course, one semiconductor laser or one in the LDB. Even in the case of a failure of two laser drivers, the printout can be reliably performed at a low speed.

  Since the printer controller 100 having the same function can be used in both the first embodiment and the second embodiment, the use expandability of the printer controller 100 is high.

1 is a front view showing an appearance of a full-color copying machine that is an embodiment of the present invention. FIG. 2 is an enlarged longitudinal sectional view showing an outline of an image forming mechanism of an image forming unit PTR of the printer PTR shown in FIG. 1. FIG. 3 is an enlarged plan view of the exposure device 5 shown in FIG. 2. FIG. 2 is a block diagram showing an outline of a control circuit of the printer PTR shown in FIG. 1 and a printer controller 100 in the copier shown in FIG. 1 for transferring image data thereto. FIG. 5 is a time chart showing timing signals and control signal generation timings generated in each part of the control circuit of the printer PTR shown in FIG. 4, and the horizontal axis is the time axis. 5 is a time chart showing timings of generation of timing signals, control signals and transfer image data generated by the control circuit of the printer PTR and the copy application 115 shown in FIG. 4, and the horizontal axis is a time axis. 4 is a time chart showing timing signals, control signals, image data generation timings, and transfer timings generated by the LDB (Y) 111 and the copy application 115 shown in FIG. 4 in the first embodiment of the present invention. Is the axis. 4 is a time chart showing timing signals, control signals, image data generation timings and transfer timings generated by the LDB (Y) 111 and the copy application 115 shown in FIG. Is the axis.

Explanation of symbols

5: writing unit 6a to 6d: photosensitive drums 7a to 7d: developing device 8: paper feed cassette 9: driving roller 10: transfer belt 11a to 11d: transfer device 12: fixing device 13a: tension roller 13b: driven roller 20r, 20f: Optical sensors 31y, 31m, 31c, 31bk: Laser diode unit (LD unit)
3231ym, 32c, 32bk: cylinder lens 33bk, 33y: reflection mirror 34: polygon mirror 35bkc, 35ym: fθ lens 36y, 36m, 36c, 36bk: first mirror 37bkc, 37ym: cylinder mirror 38bkc, 38ym: sensor 39bkc, 39ym : Cylinder mirror 40bkc, 40ym: Sensor

Claims (6)

A control signal for transferring image data is generated based on a synchronization signal generated in a line writing cycle, simultaneously receiving image data of a plurality of lines, and converting the image data of each line into each of one or more a writing means. An image forming apparatus comprising: a printer that performs writing based on; and a printer controller that, in response to the control signal, simultaneously transfers image data of a plurality of lines b and b of a or more lines to the printer in parallel.
When the a is less than b, the printer generates the control signal at a cycle of b / a times the synchronization signal, gives it to the printer controller, and based on the b-line image data received from the printer controller. Each writing unit performs writing for each line during one period of the synchronization signal.   Even when a = b, the printer generates the control signal at a cycle of b / a times the synchronization signal, gives it to the printer controller, and based on the b-line image data received from the printer controller. The image forming apparatus according to claim 1, wherein each writing unit performs writing for each line during one cycle of the synchronization signal.   The printer includes one photosensitive member, an a number of semiconductor lasers and an exposure unit that scans and exposes the photosensitive member using a writing controller that drives the semiconductor laser, and a synchronization detection unit that detects synchronization of the exposure unit, A laser exposure electrophotographic printer comprising: control signal generation means for generating the control signal at a cycle of b / a times the cycle based on the synchronization detection signal from the synchronization detection means and supplying the control signal to the printer controller. The image forming apparatus according to claim 1 or 2.   A is plural, and the synchronization detection means detects a scanning exposure laser generated by the a number of semiconductor lasers; and the printer further detects the a scanning exposure lasers generated by the synchronization detection means. 4. The image forming apparatus according to claim 3, further comprising synchronization separation means for generating a synchronization detection signal addressed to each laser based on the signal.   A plurality of sets of one-color image forming mechanisms including the photoconductor and a mechanism for forming images on the photosensitive member for different-color image forming, and each color image formed by each image forming mechanism being transferred and superimposed on a sheet of paper; The color image forming apparatus according to claim 1, further comprising: Imaging means for taking an image and generating image data representing the image; and the printer controller includes an image memory for storing image data generated by the imaging means, and the image data in the image memory is transferred to the printer. The image forming apparatus according to any one of claims 1 to 5.

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