JP2006082525A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize an image forming device excellent in expandability of application boards, and providing a high-quality image free from color shift and high-quality security management. <P>SOLUTION: The image forming device has a process cartridge, and is provided with a transfer trigger signal generating means for generating a main scanning line trigger signal and a subscanning effective area trigger signal from a synchronization detection signal detected by a synchronization detection means. The device generates a main scanning line synchronization signal and a subscanning effective area signal from a main scanning line trigger signal and a subscanning effective area trigger signal generated by the transfer trigger signal generating means, transfers image information to an exposure means, synchronizing with the main scanning line synchronization signal and the subscanning effective area signal, and changes a period of the main scanning line trigger signal from information stored in a storing means mounted in the cartridge, according to a print mode of the image information transferred from an application board. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus using a semiconductor laser as image writing means.

  Conventionally, image processing apparatuses such as copiers, facsimile machines, and laser printers used as computer output devices are rapidly increasing in memory capacity, high-speed processing, high image quality, high functionality, and low price in controllers. In addition, not only binary printing by so-called monochrome printing, but also a method of converting multi-value image data into binary image data and outputting the converted print data has been adopted.

  In addition, a pulse width modulation method has been proposed and put into practical use as a technique for achieving both resolution and halftone reproducibility at a higher level. However, with this technology, due to the characteristics of electrophotography, it is necessary to perform pulse width modulation for several dots at a time in order to obtain a good halftone image, but the resolution when printing characters, line drawings, etc. is reduced. There was a problem.

  In view of this, there has been proposed a printer having different resolutions for printing a halftone image such as a photograph and for printing a text (binary) image such as a character line drawing. In this technique, text image printing is performed at 300 dpi, and multi-level image printing is performed at 150 dpi using pulse width modulation. All text images are written in binary image memory, and image images are stored in multi-level image memory. Each image is output in a superimposed manner so that both the character image portion and the image image portion have high quality. However, in this technique, a difference in resolution between images becomes a problem, and there is a case where a gap occurs at the outline portion of the character or the boundary between the character and the image or the image looks unnatural.

  In order to solve such a problem, an “image forming apparatus” described in Patent Document 1 is presented. According to this technique, when binary image data and multi-value image data are mixed, in a frame memory configured with 4 bits per image, the lower 1 bit is represented as binary image data representing the monochrome of the binary image. The binary values “0” and “1” are assigned, the remaining 2 to 15 (14-value image density of 0/13 to 13/13 per pixel) are assigned as multi-value image data, and the data is developed. The boundary portion between the binary image and the multi-valued image is made clear.

  In addition, a multifunctional image forming apparatus in which a printer function, a scanner function, a copier function, and a facsimile function are combined has been proposed. Each function has its own control program, and each control program is not compatible. Therefore, in order to combine each function, the software and hardware aspects of the control program need to be changed and replaced, which takes time to construct the system, and further complicates and increases costs. It was.

  In particular, in color copiers, there is a difference between the reading characteristics in the scanner section and the output characteristics in the printer section, and in the CRT, the display, reading, and printing colors differ depending on the monitor characteristics. A correction circuit is incorporated in the apparatus so that the image data has linear characteristics. Therefore, when the above functions are combined, a correction circuit must be mounted on each function, and there is a concern that the device is expensive and large.

In response to such a problem, a “composite image forming apparatus” described in Patent Document 2 has been proposed.
According to this technique, a host computer is installed as a system unit, and an image processing terminal having functions of a printer, a scanner, a facsimile machine, and a copying machine is connected to a general-purpose bus. Since each of these image processing terminals shares a general-purpose bus, the system can be expanded as necessary. The image processing terminal is connected to the host computer based on a data request from each image processing terminal. Further, the image quality is corrected according to the image data input from the image processing terminal, and the correction data is changed according to the connected image terminal to cope with the image quality correction of a plurality of image processing terminals.

  In addition, as a multicolor image forming apparatus that performs color printing, for example, an image forming unit that performs printing of yellow (Y), magenta (M), cyan (C), and black (BK) is disposed, and printing of each color is sequentially performed. A tandem multicolor image forming apparatus is known. In this apparatus, yellow (Y), magenta (M), cyan (C), and black (BK) toners are sequentially transferred onto a sheet as a transfer material to form a color image. The accuracy of the installation position is important. This is because if the accuracy is poor, the formed image will be misaligned, resulting in a decrease in print quality.

  In order to prevent this color image misalignment, a technique has been proposed in which a detecting unit is provided in the apparatus, the passage of the transfer material is detected to drive the printer mechanism, and the timing of image transfer is measured. In addition, a marker image is written on the transfer material by the laser writing system of the first unit of the plurality of image forming units, and the marker image written on the transfer material is detected by a detector disposed in the subsequent forming unit. There has been proposed a technique for preventing an image shift by timing the transfer of the image.

  However, these proposed techniques can prevent color misregistration in the transfer material transport direction, that is, the sub-scanning direction, but can prevent color misregistration in the main scanning direction and the oblique direction perpendicular to the sub-scanning direction. There wasn't.

  Regarding this problem, a “multicolor image recording apparatus” described in Patent Document 3 is presented. The technology of this device electrically aligns the tandem color printer in the sub-scanning direction, main-scanning direction, and diagonal direction, and this method reduces mechanical accuracy, assembly and adjustment time. It was possible to reduce the cost. In addition, a high-quality multicolor image recording apparatus is realized by accurately superimposing images in the sub-scanning direction.

  In recent years, printers with a cost reduction function such as a toner saving mode are generally used. This printer with a cost reduction function is designed so that the operator can select toner saving, energy saving, and paper saving modes of the printer by inputting from the client PC. However, in this technique, for example, switching of the printer driver to the toner saving mode has to be performed using a client PC connected to the printer.

  Further, when a plurality of client PCs are connected via a network and share one printer, each connected client PC has to switch to the toner saving mode.

  Regarding this problem, an “image forming apparatus, process cartridge, and set value storage medium” disclosed in Patent Document 4 is presented. An image forming apparatus according to this technique has a device configuration in which a process cartridge in which a setting value change trigger for changing an image forming condition is recorded is detachable, and a detection unit that detects a setting value change trigger from the process cartridge, Change means for changing the set value recorded in advance in the storage means to a set value corresponding to the set value change trigger.

According to the proposed image forming apparatus, by using a process cartridge in which a set value change trigger is recorded or a storage medium in which a set value change is recorded, an image can be obtained simply by mounting the process cartridge or the storage medium. The forming apparatus can easily set a toner saving mode, an energy saving mode, a duplex printing mode, and the like, and an operator can perform these mode settings without troublesome operations.
JP 7-38752 A JP-A-8-149241 Japanese Patent No. 3353629 JP 2002-2069 A

  However, in these conventional image forming apparatuses, it is not possible to realize cost reduction or downsizing because the operator must input correction data or an additional hardware part. . Even when a device such as a process cartridge is used, the setting conditions are stored in advance in the memory of the image forming apparatus, and the memory cannot be effectively used. Further, when an unsuitable process cartridge is set, a problem that a low-quality image is formed occurs, and in some cases, a problem such as toner scattering occurs.

  An object of the present invention is to provide an image forming measure that is capable of forming a high-quality image with excellent extensibility of an application board and no color shift.

  The invention described in claim 1 includes at least one photosensitive member, at least one exposure unit that scans and exposes an electrostatic latent image on the photosensitive member, and at least one synchronization detection unit that detects synchronization of the exposure unit, An image forming apparatus in which at least one image forming member is formed into a cartridge, and a transfer trigger for generating a main scanning line trigger signal and a sub-scanning effective area trigger signal from a synchronization detection signal detected by the synchronization detection means A main scanning line synchronization signal and a sub-scanning effective area signal are generated from a signal generation means and the main scanning line trigger signal and the sub-scanning effective area trigger signal generated by the transfer trigger signal generation means, and the main scanning line synchronization signal The image information is transferred to the exposure means in synchronization with the sub-scanning effective area signal, and the print mode of the image information transferred from the application board is set. Flip and wherein the varying the period of the main scanning line trigger signal from the information stored in the onboard memory means to said cartridge.

  According to a second aspect of the present invention, in the first aspect of the present invention, the image information stored in the storage unit depends on a pixel density of image information transferred from the application board and an exposure density of the exposure unit. It is information for changing the period of the main scanning line trigger signal.

  According to a third aspect of the present invention, in the second aspect of the present invention, at least the sub-scanning effective area signal from the application board is at least during a period in which the transfer trigger signal generating means varies the period of the main scanning line trigger signal. It is a period indicating an effective area.

  According to the first aspect of the present invention, the image forming apparatus main body does not have the image delay means for correcting the difference in LD exposure position of each color, and the function is applied to an application board such as a printer controller, a copier application, a FAX application, or the like. By letting the main body side notify the timing of transferring the image information for each color, the image memory can be used effectively, and the cost of the entire system can be reduced.

  According to the invention of claim 2, when the application board is, for example, a printer controller, the pixel density is 1200 dpi, 600 dpi, or 300 dpi. The copier app is 600 dpi, and the fax app is 16 / mm.

  Therefore, the LD writing density is fixed to 1200 dpi, the main and sub-scanning pixel densities are doubled by the LDB (LD control board), and the I / F with the application board is sent from the application board to the XDPSYNC (synchronization detection signal) from the LDB. By varying the image information according to the pixel density of the transferred image information, it is possible to obtain a simple and clear I / F in which image information for one line is transferred by one main scanning line synchronization signal.

  Furthermore, by writing the number of lines of image information for one main scanning line synchronization signal corresponding to the pixel density in advance in the nonvolatile memory built in the process cartridge and generating XDPSYNC from the LDB based on this Since normal output images can be obtained only with process cartridges that ensure quality, it is possible to prevent deterioration of images due to setting of non-suitable cartridges, and to maintain output image quality at all times. It becomes.

  According to the third aspect of the present invention, even if the next print job occurs immediately, it is possible to respond immediately by performing the process of matching the pixel density and the writing density only during the assertion period of XIPUFGT output from the application board. It becomes possible to do.

  FIG. 1 shows the configuration of an embodiment of the image forming apparatus of the present invention. This apparatus is a configuration example of a color image forming apparatus called a general tandem type in which image forming units are arranged along a conveyance belt.

  This apparatus mainly includes a conveyance belt 2 that conveys the transfer paper 1, conveyance rollers 3 and 4 for moving the conveyance belt 2 at a predetermined speed, a paper feed tray 5 that stores the transfer paper, and yellow (Y), An image forming unit 100 that forms an image of each color of magenta (M), cyan (C), and black (K); an exposure unit 8 that exposes an image forming unit of each color of the image forming unit 100; a transfer unit 120; And a resist sensor 14.

Here, an outline of the operation of the present apparatus will be described.
Image forming sections 100 that form images of different colors (yellow: Y, magenta: M, cyan: C, black: K) are arranged in a line from the upstream to the downstream in the transport direction along the transport belt 2 that transports the transfer paper 1. It is arranged. One of the conveyor belts 2 is a drive roller that is driven to rotate, and the other is driven by conveyor rollers 3 and 4 that are driven rollers that are driven to rotate. The conveyor belt 2 is rotationally driven in the direction of the arrow by the rotation of the conveyor rollers.

  A paper feed tray 5 in which the transfer paper 1 is stored is disposed below the conveyance belt 2. The transfer sheet 1 at the uppermost position among the transfer sheets 1 stored in the sheet feed tray 5 is fed at the time of image formation, and is timed with each unit by a registration sensor 14 on the way. To be adsorbed. The adsorbed transfer sheet 1 is conveyed to the first image forming unit (yellow) 101 of the image forming unit 100, where yellow image formation is executed.

  The first image forming unit (yellow) 101 includes a photosensitive drum 6Y, and a charger 7Y, an exposure unit 8, a developing unit 9Y, and a photosensitive cleaner 10Y disposed around the photosensitive drum 6Y. Yes. The surface of the photosensitive drum 6Y is uniformly charged by the charger 7Y, and then exposed by the exposure device 8 with the laser beam 11Y corresponding to the yellow image, thereby forming an electrostatic latent image.

  The formed electrostatic latent image is developed by the developing device 9Y, and a toner image is formed on the photosensitive drum 6Y. This toner image is transferred by the transfer device 12Y at a position (transfer position) in contact with the photosensitive drum 6Y and the transfer paper 1 on the transport belt 2, and a single color (yellow) image is formed on the transfer paper 1. After the transfer, the photosensitive drum 6Y is cleaned of unnecessary toner remaining on the surface of the photosensitive drum 6Y by the photosensitive cleaner 10Y to prepare for the next image formation.

  As described above, the transfer sheet 1 on which the single color (yellow) is transferred by the first image forming unit 101 is conveyed to the second image forming unit (magenta) 102 by the conveying belt 2. Similar to the first image forming apparatus 101, the second image forming apparatus 102 includes a photosensitive drum 6M, a charger 7M disposed around the photosensitive drum 6M, an exposure device 8, a developing device 9M, and a photosensitive member. It is composed of a cleaner 10M. The surface of the photosensitive drum 6M is uniformly charged by a charger 7M, and then exposed by a laser beam 11M corresponding to a magenta image by an exposure device 8 to form an electrostatic latent image.

  The formed electrostatic latent image is developed by the developing device 9M, and a toner image is formed on the photosensitive drum 6M. This toner image is transferred by the transfer device 12M at a position (transfer position) in contact with the photosensitive drum 6M and the transfer paper 1 on the transport belt 2, and is transferred onto the transfer paper 1 in an overlapping manner. After the transfer, the photosensitive drum 6M is cleaned with unnecessary toner remaining on the surface of the photosensitive drum 6M by the photosensitive cleaner 10M to prepare for the next image formation.

  The transfer sheet 1 on which magenta has been transferred by the second image forming unit 102 is conveyed to the third image forming unit (cyan) 103 by the conveying belt 2. Similar to the first image forming apparatus 101 and the second image forming apparatus 102, the third image forming apparatus 103 includes a photosensitive drum 6C, a charger 7C disposed around the photosensitive drum 6C, and an exposure unit 8. And a developing device 9C and a photoreceptor cleaner 10C. The surface of the photosensitive drum 6C is uniformly charged by the charger 7C, and then exposed by the exposure device 8 with the laser light 11C corresponding to the cyan image to form an electrostatic latent image.

  The formed electrostatic latent image is developed by the developing device 9C, and a toner image is formed on the photosensitive drum 6C. This toner image is transferred by the transfer device 12C at a position (transfer position) in contact with the photosensitive drum 6C and the transfer paper 1 on the conveyor belt 2, and is transferred onto the transfer paper 1 in an overlapping manner. After the transfer, the photoreceptor drum 6C is cleaned with unnecessary toner remaining on the surface of the photoreceptor drum 6C by the photoreceptor cleaner 10C to prepare for the next image formation.

  The transfer paper 1 on which cyan has been transferred by the third image forming unit 103 is conveyed to the fourth image forming unit (black) 104 by the conveying belt 2. Similar to the first image forming apparatus 101, the second image forming apparatus 102, and the third image forming apparatus 103, the fourth image forming apparatus 104 is disposed around the photosensitive drum 6K and the photosensitive drum 6K. The charging unit 7K, the exposure unit 8, the developing unit 9K, and the photoconductor cleaner 10K. The surface of the photosensitive drum 6K is uniformly charged by a charger 7K, and then exposed by a laser beam 11K corresponding to a cyan image by an exposure unit 8, thereby forming an electrostatic latent image.

  The formed electrostatic latent image is developed by the developing device 9K, and a toner image is formed on the photosensitive drum 6K. This toner image is transferred by the transfer device 12K at a position (transfer position) in contact with the photosensitive drum 6K and the transfer paper 1 on the conveying belt 2, and transferred onto the transfer paper 1 in an overlapping manner. After the transfer, the photoreceptor drum 6K is cleaned with unnecessary toner remaining on the surface of the photoreceptor drum 6K by the photoreceptor cleaner 10K to prepare for the next image formation.

  In this way, a color image is formed on the transfer paper 1 by the first image forming apparatus 101 to the fourth image forming apparatus 104 of yellow, magenta, cyan, and black. Next, the transfer paper 1 on which the color image is formed is peeled off from the transport belt 2, fixed by the fixing device 13, and then discharged.

2 and 3 show a configuration example of another embodiment of the image forming apparatus using the present invention.
In this embodiment, the image forming member is formed into a cartridge. FIG. 2 is an enlarged view of the process cartridge 201, and FIG. 3 is a block diagram of the entire image forming apparatus 300 in which the process cartridge of FIG. Has been.

The configuration of the process cartridge (yellow) 201 in FIG. 2 will be described.
The image forming apparatus 300 incorporates yellow, magenta, cyan, and black process cartridges 301 to 304, and the process cartridges have the same configuration.
The process cartridge 301 is mainly composed of a photoreceptor unit 200A and a developing unit 200B. 200A and 200B may have an integral structure.

  The photosensitive drum 206 is rotated clockwise by a driving device (not shown), and the surface thereof is charged to a predetermined potential by a charging roller 207. Further, the charging roller 207 is provided with a cleaning roller 207B to clean the surface of the charging roller 207. The uniformly charged photosensitive drum 206 is exposed with a light beam L from an optical unit (not shown) to form a latent image.

  The developing unit 200B is equipped with a developing roller 241, a conveying screw 242 and 243, a developing doctor 244, and a toner concentration sensor 245, which are arranged so as to be partially exposed from the opening of the developing case 240, and is a toner storage container 350 in FIG. The toner can be supplied from the toner.

  The developing case 240 contains a two-component developer (hereinafter simply referred to as a developer) containing a magnetic carrier and a negatively charged toner. The developer is frictionally charged while being agitated and conveyed by the conveying screws 242 and 243 and then carried on the surface of the developing roller 241.

  Next, the developer carried on the surface of the developing roller 241 has its layer thickness regulated by the developing doctor 244 and is conveyed to the developing position facing the photosensitive drum 206. Therefore, toner adheres to the electrostatic latent image formed on the photosensitive drum 206. By this toner attaching operation, a predetermined color toner image is formed on the photosensitive drum 206.

  The developer that has consumed toner by the development is returned to the developing case 240 as the developing roller 241 rotates. The toner density of the developer in the developing case 241 is detected by the toner density sensor 245, and the toner is replenished from the toner container 350 shown in FIG. 3 to the space above the screw 243 as necessary.

  The process cartridge 200 is provided with holes (not shown) provided in the flanges at both ends of the photosensitive drum 206 as positioning main reference portions as a reference when the cartridge is attached to and detached from the image forming apparatus main body 300. Positioning reference portions (not shown) are provided on the frame on the front side and the back side of the drum 206, respectively. When the photoconductor unit 200A is mounted on the image forming apparatus main body 300, the reference unit and the engaging portion provided on the main body are formed so that the photoconductor unit 200A can be reliably positioned at a predetermined mounting position. Yes.

  The photosensitive drum 206 is in contact with the intermediate transfer belt 302 of the transfer unit disposed above the photosensitive drum 206 to form a transfer nip as a transfer position. The toner developed on the photosensitive drum 206 is transferred onto the intermediate transfer belt 302, and the toner remaining on the photosensitive member 206 without being transferred is removed by the cleaning blade 210B and is not shown by the toner conveying auger 210C. It is transported to the storage unit.

  In the above embodiment, the case of a tandem type color laser printer has been described. However, the present invention can also be applied to a monochrome laser printer including a set of toner image forming units using black toner. The present invention can also be applied to other image forming apparatuses such as copying machines, printers, and facsimile machines.

FIG. 4 is a block diagram of an optical unit related to an image forming apparatus using the present invention. The configuration and operation will be described with reference to the configuration diagram of FIG.
Light beams from the LD unit BK431 and the LD unit Y432 pass through the cylinder lenses CYL_BK433 and CYL_Y434, enter the lower surface of the polygon mirror 437 by the reflection mirror BK435 and the reflection mirror Y436, and deflect the light beam by rotating the polygon mirror 437. Then, the light passes through the fθ lens BKC438 and the fθ lens YM439 and is folded back by the first mirror BK440 and the first mirror Y441.

  On the other hand, the light beams from the LD unit C442 and the LD unit M443 pass through the CYL_C444 and CYL_M445, enter the upper surface of the polygon mirror 437, and the polygon mirror 437 rotates to deflect the light beam, thereby fθ lenses BKC438 and fθ. It passes through the lens YM439 and is folded back by the first mirror C446 and the first mirror M447.

  Cylinder mirrors CYM_BKC448 and CYM_YM449, and further sensors BKC450 and YM451 are provided upstream from the writing position in the main scanning direction. It is configured to enter the sensor BKC450 and the sensor YM451. These sensors are synchronization detection sensors for synchronizing in the main scanning direction.

In addition, the light beams from the LD unit BK431 and the LD unit C432 use the common CYM_BKC448 and sensor BKC450. The same applies to the LD unit Y432 and the LD unit M443. Since two color light beams are incident on the same sensor, by changing the incident angles of the light beams of the respective colors to the polygon mirror 437, the timing at which each light beam enters the sensor is changed. It is output in series as a pulse train. As shown in FIG. 4, BK and C and Y and M are scanned in the reverse direction.
In addition, about the method of isolate | separating the output from the synchronous detection sensor common to two colors into each color component, since various methods are proposed conventionally, it abbreviate | omits in description of a present Example.

FIG. 5 is a block diagram showing a control circuit of the image forming apparatus of the present embodiment.
6 to 8 show timing charts of the control circuit of FIG.
The copier application 500 transfers image data to be printed by the image forming apparatus to the timing_Y generation circuit 502, the timing_M generation circuit 504, the timing_C generation circuit 503, and the timing_K generation circuit 505 for each color.

  The synchronization separation (Y) 507 and the synchronization separation (M) 508 are circuits that separate the output of the sensor YM451 described in FIG. 4 into respective synchronization signals. Similarly, the synchronization separation (C) 509 and the synchronization separation (C) The separation (K) 510 is a circuit that separates the output of the sensor BKC 450 into each synchronization signal. Further, the LDB (Y) 511 is built in the LD unit Y532. Similarly, the LDB (M) 512 is built in the LD unit M543, the LDB (C) 513 is built in the LD unit C542, and the LDB (K) 514 is built in the LD unit BK531. Has been.

Next, the timing chart of FIG. 6 will be described.
DETP_Y is output from the synchronization separation (Y) 507, DETP_M from the synchronization separation (M) 508, DETP_C is output from the synchronization separation (C) 509, and DETP_K is output from the synchronization separation (K) 510. DETP_Y, DETP_M, DETP_C, and DETP_K are asynchronous signals. This is because the same mirror surface is not used on the YM side and the CK side, and the position of the LD light emitted from each LD unit is different.

  However, the period indicated by X in FIG. 6 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. LDB (Y) outputs a signal DPSYNC_Y synchronized with the write clock of LD from DETP_Y to Y to the reference selection circuit 506. Similarly, LDB (M) 512 outputs DPSYNC_M, LDB (C) 513 outputs DPSYNC_C, and LDB (K) 514 outputs DPSYNC_K. The reference selection circuit 506 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 502 delays XSTART output from the registration sensor 501 until CNT_LD, counts DPSYNC_Y by the number of lines set to PFGDY_Y, asserts XFSYNC_Y, and transfers it to the copier application 500 together with XWRSYNC_Y.

  Similarly, other XFSYNC_Ms are asserted by counting with DPSYNC_M for the set number of lines from CNT_LD to PFGDL_M. Also, XFSYNC_C is asserted by counting DPCNT_C from CNT_LD to the number of set lines PFGDLY_C, and XFSYNC_K is asserted by DPSYNC_K by the number of lines set from CNT_LD to PFGDY_K, and is transferred to XWRSYNC_M, XWRSYNC_C, XWRSYNC_K, and XWRSYNC_K. The

  The copier application 500 generates XIPUFGT from the XFSYNC of each color, generates XIPULSYC from the XWRSYNC, returns IPUDAT to the LDB corresponding to each color, and exposes the image information from the copier application 500. FIG. 7 shows a timing chart thereof. In this example, the pixel density on the application side and the writing density on the image forming apparatus side are the same.

  In this embodiment, an example in which a copier application (copier application board) 500 is connected has been described. However, even if the copier application is replaced or added to a printer controller or a fax application, the same I / F is obtained. Image formation can be easily performed. For example, in the case of expansion, a selection signal for selecting an application is provided, and the output of an unselected application is set to Hi-z.

  Further, in the case of three types of applications, ie, a copier application, a printer controller, and a FAX application, the pixel density of image information differs due to the difference in function of the application. For example, 1200, 600, and 300 dpi are the mainstream printer controllers, but 600 dpi for copier apps, and the main / mm resolution is the mainstream for fax apps, not the dpi resolution, and pixel densities vary widely.

  Therefore, in order for the image forming apparatus to cope with these, it is necessary to variably control the rotational speed of the polygon motor and the frequency at which the LD is turned on each time. A method is generally used in which the writing density of the image forming apparatus is 1200 dpi, which is the least common multiple of the pixel density, and the difference between the pixel density and the writing density is doubled using a line memory or the like. However, with such a configuration, the above-described mismatch occurs between the application board and the image forming apparatus, and the I / F also varies.

  Therefore, in the present invention, the fixed DETP signal is used as a reference, line thinning is performed based on the pixel density, and one XWRSYNC is generated as the basis of the main scanning line synchronization signal (XIPULSYC) output from the application side. It realizes a simple and understandable I / F in which one line of data is transferred to the application side for XWRSYNC.

FIG. 8 shows a timing chart of an example in which the pixel density on the application side is ½ of the writing density, that is, the pixel density is 600 dpi and the writing density is 1200 dpi.
Here, the difference between the pixel density and the writing density described above is that the timing generation circuit corresponding to each color asserts XFSYNC and then performs ½ decimation based on XLDSYNC and outputs it to the application board as XWRSYNC. Is done.

  When these XFSYNC and XWRSYNC are input, the application board starts transfer so that XIPUFGT, XIPULSYC, and IPUDAT become 1: 1 based on them. The XIPUFGT negates the XIPUFGT when the transfer of the image information for a predetermined number of lines is completed.

  When the XIPUFGT is negated, the timing generation circuit stops the XWRSYNC thinning process, returns to the normal timing, and waits for the next image formation. Here, the LDB uses a line memory to perform 1200 dpi by doubling processing, and exposes the photosensitive drum.

  Other pixel densities can be dealt with by applying this method. Also, regarding the density of 16 lines / mm system used in the FAX application, when converted to dpi, it becomes 406 dpi, and a polygon motor and fine adjustment are necessary. However, the timing generation circuit approximates the pixel density of 400 dpi, and performs a doubling process three times. It becomes possible to cope by doing.

  In this embodiment, a printed circuit board having a nonvolatile memory 201 mounted in a cartridge is incorporated. In this nonvolatile memory, information on how many lines of XWRSYNC are to be output to the XLDSYNC1 line is stored in advance based on the pixel density on the application side and the writing density on the image forming apparatus side. Based on this information, the control circuit shown in FIG. 5 described above executes an operation, and appropriate image exposure is performed.

  Therefore, by not disclosing and disclosing this information for cartridges that cannot guarantee proper quality, it becomes impossible to perform proper image exposure, and it is possible to eliminate poor products.

  In this embodiment, a non-volatile memory board is used. However, instead of the non-volatile memory board, a contact type printed circuit board mounted with an IC chip, or a printed circuit board or non-contact type IC mounted with a non-contact type IC chip. A card may be mounted.

1 is a configuration diagram of a first embodiment of an image forming apparatus of the present invention. 2 is a diagram illustrating a configuration example of a process cartridge (yellow) 201. FIG. 1 is a diagram illustrating an overall configuration of an image forming apparatus 300 in which a process cartridge is incorporated. 1 is a configuration diagram of an optical unit of an embodiment of an image forming apparatus of the present invention. It is a figure which shows the structural example of a control circuit. 6 is a timing chart showing signal operations of the control circuit of FIG. 5. 6 is a timing chart showing signal operations of the control circuit of FIG. 5. 6 is a timing chart showing signal operations of the control circuit of FIG. 5.

Explanation of symbols

2 Conveying belt 3, 4 Conveying roller 5 Paper feed tray 6, 6 Y Photosensitive drum 8 Exposure unit 120 Transfer unit 13 Fixing unit 14 Registration sensor

Claims (3)

At least one photosensitive member, at least one exposure unit that scans and exposes the electrostatic latent image on the photosensitive member, at least one synchronization detection unit that detects synchronization of the exposure unit, and at least one imaging member Is an image forming apparatus in a cartridge,
Transfer trigger signal generating means for generating a main scanning line trigger signal and sub-scanning effective area trigger signal from the synchronization detection signal detected by the synchronization detecting means, and the main scanning line trigger signal generated by the transfer trigger signal generating means And a sub-scanning effective area trigger signal to generate a main scanning line synchronization signal and a sub-scanning effective area signal, and transfer image information to the exposure means in synchronization with the main scanning line synchronization signal and the sub-scanning effective area signal. An image forming apparatus, wherein a period of a main scanning line trigger signal is varied from information stored in a storage unit mounted on the cartridge according to a printing mode of image information transferred from a board.   The image information stored in the storage means is information that varies the period of the main scanning line trigger signal according to the pixel density of the image information transferred from the application board and the exposure density of the exposure means. The image forming apparatus according to claim 1, wherein:   3. The period in which the transfer trigger signal generation unit varies the period of the main scanning line trigger signal is a period in which the sub-scanning effective area signal from the application board indicates at least an effective area. Image forming apparatus.

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