CN106919024B

CN106919024B - Controller

Info

Publication number: CN106919024B
Application number: CN201610986794.2A
Authority: CN
Inventors: 武田庄司; 山崎克之
Original assignee: Canon Inc
Current assignee: Canon Inc
Priority date: 2015-11-20
Filing date: 2016-11-08
Publication date: 2019-12-27
Anticipated expiration: 2036-11-08
Also published as: CN106919024A; JP6784561B2; JP2017100440A

Abstract

The invention discloses a controller. A setting unit of a controller mounted on a control board sets a first mode for generating PWM data representing a pattern for causing LD to emit light from image data and transmitting to a laser drive board, or a second mode for transmitting image data before generation of the PWM data to the laser drive board. A data conversion unit converting the input image data into N PWM data respectively corresponding to the N LDs in the first mode, and converting the input image data into image data for each scan line in the second mode. The P/S conversion unit converts the data output from the data conversion unit from a serial format to a parallel format, and transmits the converted data to the laser driving board as control data.

Description

Controller

Technical Field

The present invention relates to a controller for an electrophotographic image forming apparatus.

Background

The following electrophotographic image forming apparatuses are known: which deflects a light beam (laser beam) emitted from a laser light source by rotating a polygon mirror and scans a photosensitive member by the deflected laser beam to form an electrostatic latent image on the photosensitive member. In such an image forming apparatus, generally, image data generated by a control board mounted with a system controller as an integrated circuit is transmitted to a laser driving board mounted with a laser driver for driving a laser light source, which drives the laser light source based on the received image data.

Further, the following multi-beam type image forming apparatus is known: which includes, as a light source, a plurality of light emitting elements for emitting a plurality of light beams that respectively scan different rows in parallel on a photosensitive member, in order to achieve high-speed image forming speed and high-resolution image. There are the following problems: in such a multi-beam type image forming apparatus, as the number of light emitting elements increases, the number of signal lines (including printing wiring and cables) between the system controller and the laser driver also increases. In this regard, japanese patent application laid-open No. 2011-31451 describes a technique of performing data serial transmission between a system controller and a laser driver, and the number of signal lines can be reduced by using the serial transmission.

There are the following situations: in accordance with manufacturing costs and the like, a laser driver incorporating a laser driving board including a conversion circuit for converting image data into a PWM signal or a laser driver incorporating a conversion circuit is installed in an image forming apparatus, and there are cases where: a laser driving board not including such a conversion circuit is mounted. Therefore, regardless of whether or not the PWM signal is generated on the system controller side and serial transmission of the PWM signal is performed to the laser driver, the design of the system controller must be changed to match the configuration of the laser driver or the laser driving board installed in the image forming apparatus. On the other hand, it is necessary to realize a system controller that is not affected by the configuration of the laser driver or the laser driving board.

Disclosure of Invention

The present invention has been conceived in view of the above problems. The present invention provides a technique for improving versatility of a controller relating to a driver board for driving a light emitting element.

According to an aspect of the present invention, there is provided a controller mounted on a control board of an image forming apparatus, the image forming apparatus including: an optical scanning device including a drive board on which a laser light source having a light emitting element that emits a light beam and a laser driver that drives the laser light source based on drive data are mounted, and the control board that transmits data to the drive board via a cable, the controller including: a setting unit configured to set, as an operation mode, a first mode in which drive data representing a pattern for causing the light emitting elements to emit light is generated based on image data and transmitted to the drive board, and a second mode in which the image data is transmitted to the drive board without converting the image data into the drive data, wherein the drive data is binary data configured according to data for causing the light emitting elements to turn on and data for causing the light emitting elements to turn off, and the image data is multivalued data representing density gradation; a data conversion unit configured to, in the first mode, convert input image data into drive data of the number of light emitting elements that the laser light source has and output the converted drive data to the drive board, and in a second mode, convert the input data into image data of each scan line in scanning of a photosensitive member by the light beam and output the converted image data; and a transmission unit configured to continuously transmit the data output from the data conversion unit to the driving board.

According to another aspect of the present invention, there is provided a controller mounted on a control board of an image forming apparatus, the image forming apparatus including: an optical scanning device including a driving board on which a laser source having a light emitting element that emits a light beam and a laser driver that drives the laser source are mounted, and the control board that transmits data to the driving board via a cable, the controller including: a setting unit configured to set a first pattern of outputting drive data to the drive board and a second pattern of outputting density data to the drive board, wherein the drive data is binary data configured according to data to turn on the light emitting elements and data to turn off the light emitting elements, and the density data is multivalued data representing density gradation; a data conversion unit configured to convert input image data into the drive data in the first mode, and to convert input image data into density data corresponding to each of a plurality of light emitting elements that the laser light source has mounted on the drive board in a second mode; and a transmission unit configured to transmit the driving data converted by the data conversion unit to the driving board in the first mode, and transmit the density data corresponding to each of the plurality of light emitting elements converted by the data conversion unit to the driving board from the same output terminal in the second mode.

By the present invention, it becomes possible to improve the versatility of the controller relating to the driving board for driving the light emitting element.

Other features of the present invention will become apparent from the following detailed description of exemplary embodiments with reference to the attached drawings.

Drawings

Fig. 1 is a sectional view illustrating an example of a hardware configuration of an image forming apparatus.

Fig. 2 illustrates an example of a hardware configuration of the exposure unit.

Fig. 3 illustrates an example configuration of a control board and a laser driving board.

Fig. 4 illustrates an example configuration of a control board and a laser driving board.

Fig. 5 illustrates an example of a relationship between image data (density value) and PWM data of one pixel.

Fig. 6 illustrates a modification of the laser driving board illustrated in fig. 4.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the following embodiments are not intended to limit the scope of the appended claims, and not all combinations of features described in the embodiments are essential to the solution of the present invention.

< arrangement of image Forming apparatus >

Fig. 1 is a sectional view illustrating an example of a hardware configuration of an image forming apparatus 100 according to an embodiment. The image forming apparatus 100 may also be an image forming apparatus that forms a monochrome image, but it is assumed here that the image forming apparatus 100 is an image forming apparatus that forms a multicolor image using multicolor toner (developing material). The image forming apparatus 100 may also be any one of, for example, a printing apparatus, a printer, a copying machine, a multifunction peripheral (MFP), and a facsimile apparatus. Note that Y, M, C and K at the end of the reference numerals denote that the colors of the toners having the counterparts as their targets are yellow, magenta, cyan, and black, respectively. In the following description, reference numerals with Y, M, C and K omitted at the end are used in cases where color discrimination is not required.

The image forming apparatus 100 includes four image forming units (image forming stations) that form images (toner images) using toners of Y color, M color, C color, and K color, respectively. The image forming units corresponding to these colors include photosensitive drums (photosensitive members) 102Y, 102M, 102C, and 102K, respectively. Around the photosensitive drums 102Y, 102M, 102C, and 102K, there are disposed charging units 103Y, 103M, 103C, and 103K, exposure units (optical scanning devices) 104Y, 104M, 104C, and 104K, and developing units 105Y, 105M, 105C, and 105K, respectively. Note that around the photosensitive drums 102Y, 102M, 102C, and 102K, drum cleaning units (not shown) are also arranged, respectively.

An endless belt-shaped intermediate transfer belt (intermediate transfer medium) 107 is disposed below the photosensitive drums 102Y, 102M, 102C, and 102K. The intermediate transfer belt 107 is wound around a driving roller 108 and driven rollers 109 and 110. During image formation, with rotation of the driving roller 108, the outer surface of the intermediate transfer belt 107 moves in the arrow direction illustrated in fig. 1. Primary transfer bias blades 111Y, 111M, 111C, and 111K are arranged at positions facing the photosensitive drums 102Y, 102M, 102C, and 102K via the intermediate transfer belt 107. The image forming apparatus 100 further includes a secondary transfer bias roller 112 for transferring the toner image formed on the intermediate transfer belt 107 onto a sheet, and a fixing unit 113 for fixing the toner image transferred onto the sheet. Note that the sheet may also be referred to as recording paper, a recording material, a recording medium, paper, a transfer material, a transfer sheet, or the like.

Next, an image forming process from the charging process to the developing process in the image forming apparatus 100 having the above-described configuration is described. Note that image forming processes respectively performed by the image forming units corresponding to the respective colors are similar. Therefore, the image forming process in the image forming unit corresponding to the Y color will be described below as an example, and the description of the image forming process in the image forming units corresponding to the M color, the C color, and the K color will be omitted.

First, the charging unit 103Y of the image forming unit corresponding to the Y color charges the surface of the rotated photosensitive drum 102Y. The exposure unit 104Y emits a plurality of laser beams (light beams), and scans the surface of the charged photosensitive drum 102Y with the plurality of laser beams to expose the surface of the photosensitive drum 102Y. Accordingly, an electrostatic latent image is formed on the rotating photosensitive drum 102Y. The developing unit 105Y develops the electrostatic latent image formed on the photosensitive drum 102Y with Y color toner. Thereby, a toner image of Y color is formed on the photosensitive drum 102Y. Further, in the image forming units corresponding to the M color, C color, and K color, respectively, the toner images of the M color, C color, and K color are formed on the photosensitive drums 102M, 102C, and 102K, respectively, by processes similar to those of the image forming units corresponding to the Y color.

The image forming process from the transfer process will be described below. In the transfer process, first, the respective primary transfer bias blades 111Y, 111M, 111C, and 111K apply a transfer bias to the intermediate transfer belt 107. Thereby, the toner images of the four colors (Y color, M color, C color, and K color) formed on the photosensitive drums 102Y, 102M, 102C, and 102K are transferred onto the intermediate transfer belt 107 in superposition, respectively.

With the movement of the outer surface of the intermediate transfer belt 107, the toner image including four color toners formed in an overlapped manner on the intermediate transfer belt 107 is conveyed to a secondary transfer nip between the secondary transfer bias roller 112 and the intermediate transfer belt 107. The sheet is conveyed from the paper feed cassette 115 to the secondary transfer nip portion simultaneously with the timing of conveying the toner image formed on the intermediate transfer belt 107 to the secondary transfer nip portion. In the secondary transfer nip, the toner image formed on the intermediate transfer belt 107 is transferred onto a sheet by a transfer bias applied by a secondary transfer bias roller 112 (secondary transfer).

Thereafter, the toner image formed on the sheet is fixed to the sheet by heating of the fixing unit 113. The sheet on which the multicolor image is formed in this way is discharged to the discharge unit 116.

Note that after the transfer of the toner image to the intermediate transfer belt 107 is completed, the toner remaining on the photosensitive drums 102Y, 102M, 102C, and 102K is removed by the above-described drum cleaning unit (not shown). When a series of image forming processes is completed in this way, then an image forming process corresponding to the next sheet is started.

< arrangement of Exposure Unit >

Fig. 2 illustrates an example of the configuration of the exposure unit 104 according to the present embodiment. The exposure unit 104 (optical scanning device) includes a laser drive board 210 connected to a control board 220 as a system controller of the image forming apparatus 100, and various optical components 202 to 206 (collimator lens 202, cylindrical lens 203, polygon mirror (rotary polygon mirror) 204, and f θ lenses (scanning lenses) 205 and 206). The laser driving board 210 includes a laser driver 200, a laser light source 201, and a Beam Detection (BD) sensor 207.

The laser driver 200 drives the laser light source 201 by a drive current supplied to the laser light source 201. A laser light source (hereinafter, simply referred to as "light source") 201 generates and outputs (emits) a laser beam (light beam) having optical power in accordance with a drive current. The laser light source 201 includes N Laser Diodes (LDs) as light emitting elements. Here, N is an integer greater than or equal to 2. That is, the image forming apparatus 100 employs a multi-beam system in which the photosensitive element 102 is scanned by a plurality of laser beams emitted from a plurality of LDs. In the present embodiment, as shown in fig. 3 and 4, N is assumed to be 4.

The laser driver 200 performs Pulse Width Modulation (PWM) on a drive current supplied to each LD of the laser light source 201 based on image data to cause each LD to emit light. In the present embodiment, a PWM signal generated from image data by any one of the circuit in the control board 220 or the circuit in the laser drive board 210 according to the configuration of the laser drive board 210 mounted in the image forming apparatus 100 is input to the laser driver 200. The laser driver 200 supplies a drive current to each LD of the laser light source 201 according to the input PWM signal.

The collimator lens 202 makes the laser beam emitted from the light source 201 in the shape of parallel light. The cylindrical lens 203 focuses the laser beam passing through the collimator lens 202 in the scanning direction (direction corresponding to the rotation direction of the photosensitive drum 102). The laser beam passing through the cylindrical lens 203 is incident on one of the plurality of reflection surfaces included in the polygon mirror 204. The polygon mirror 204 reflects the laser beam in each reflecting surface while rotating in the arrow direction illustrated in fig. 2 to turn the incident laser beam at a continuous angle. The laser beam turned by the polygon mirror 204 is sequentially incident on f θ lenses 205 and 206. After passing through the f θ lenses 205 and 206, the laser beam becomes a scanning beam that scans the surface of the photosensitive drum 102 at a constant speed.

The exposure unit 104 includes a mirror (mirror for simultaneous detection) 208, and the mirror 208 is located at a position on the scanning path of the laser beam passing through the f θ lens 205 and on the initial side of the laser beam scanning. The laser beam passing through the end of the f θ lens is incident on the mirror 208. The BD sensor 207 is arranged in the reflection direction of the laser beam from the mirror 208, and is used as an optical sensor for detecting the laser beam. In this way, the BD sensor 207 is arranged on the scanning path of the laser beam deflected by the polygon mirror 204. That is, the BD sensor 207 is arranged on a scanning path when the surface of the photosensitive drum 102 is scanned for a plurality of laser beams emitted from the light source 201.

< control Unit operation mode >

Fig. 3 and 4 illustrate two kinds of laser driving boards 210 respectively having different configurations, which are to be installed in the image forming apparatus is determined according to specifications of the image forming apparatus and the optical scanning apparatus. The difference between these two types of laser driving boards 210 is whether or not a conversion circuit that converts image data for each scanning line that the laser beam scans the photosensitive drum 102 into N pieces of PWM data corresponding to the N LDs, respectively, is included. The control board 220 of the present embodiment has a configuration common to both of the laser driving boards 210. Note that an example in which the light source 201 includes four LDs (LD _ a, LD _ B, LD _ C, and LD _ D) (i.e., the number N of light emitting elements is 4) is illustrated in fig. 3 and 4.

A control board 220 is installed in the image forming apparatus 100. The control unit 300 installed in the control board 220 has two operation modes for performing an operation in accordance with the configuration of the laser driving board 210 connected to the control board 220, and operates in any operation mode set. The first mode is an operation mode in which PWM data is generated from image data and transmitted to the connected laser driving board. The second mode is an operation mode of transmitting image data before PWM data generation to the connected laser driving boards. The control unit 300 is set to the first mode if the laser driving board not including the conversion circuit for generating the PWM data is connected. On the other hand, if the laser driving board including the conversion circuit for generating the PWM data is connected, the control unit 300 is set to the second mode. Note that the PWM data corresponds to drive data for representing a pattern for causing the LD to emit light.

When the control board 220 and the laser driving board 210 are embedded in the image forming apparatus 100, the operation mode setting of the control unit 300 is performed on the control board 220 in advance. In the present embodiment, an example is illustrated in which a set value representing the first mode or the second mode is stored in advance in a memory, and the operation mode is set in accordance with the set value stored in the memory.

< first mode operation >

Fig. 3 illustrates an example of the configuration of a control board 220 as a system controller of the image forming apparatus 100 of the present embodiment, and the configurations of laser driving boards 210Y, 210M, 210C, and 210K corresponding to Y, M, C and K, respectively, connected to the control board 220. The laser driving boards 210Y, 210M, 210C, and 210K respectively correspond to a plurality of driving boards for image formation of different colors (Y, M, C and K). Fig. 3 illustrates an operation of the case where the control board 220 is set to the first mode to match the configuration of the laser driving boards 210Y, 210M, 210C, and 210K.

The control board 220 includes a control unit 300 (controller), a serial/parallel (S/P) conversion unit 307, and a BD detection unit 308. The control unit 300 is configured by one Integrated Circuit (IC), and the control unit 300 includes an image processing unit 301, a data conversion unit 302, a parallel/serial (P/S) conversion unit 303 (transmission unit), a setting unit 304, a ROM 305, and a RAM 306. Thus, at least the setting unit 304, the data conversion unit 302, and the P/S conversion unit 303 are mounted in the control board 220 as one IC. The control unit 300 may be configured to include an S/P conversion unit 307 and a BD detection unit 308.

In the control board 220, the image processing unit 301 and the data conversion unit 302 are connected by four data transmission lines corresponding to the four colors Y, M, C and K. The data conversion unit 302 and the P/S conversion unit 303 are connected by four data transfer lines corresponding to four (N) LDs for Y, M, C and K colors, and are connected by a total of 16(═ 4 × N) data transfer lines for the four colors.

The control board 220 is connected to the laser driving board 210 through four cables corresponding to four (N) LDs for Y, M, C and K colors. To describe the relationship between the control board 220 and the laser driving board 210Y specifically as an example, the control unit 300 is connected to a connector 309a mounted on the control board 220 by a print wiring. The control unit 300 includes one terminal for receiving data related to the BD signal output from the laser driving board 210Y and a plurality of terminals for outputting data to the laser driving board 210Y. The control unit 300 of the present embodiment includes four terminals (a first terminal, a second terminal, a third terminal, and a fourth terminal) as a plurality of terminals for outputting data to the laser driving board 210Y. These four terminals are connected to the connectors 309a mounted on the control board 220 by printed wiring. The connector 309a includes one terminal for receiving the BD signal from the laser driving board 210Y and four terminals for outputting data to the laser driving board 210Y. The connector 309a is connected to the connector 310a mounted in the laser driving board 210Y through the above-described cable.

The laser driving board 210 includes a laser driver 200, a light source 201, and a BD sensor 207. Note that the BD sensor 207 may be arranged on a substrate other than the laser driving board 210, but a BD signal generated by the BD sensor 207 or data related to the BD signal is transmitted to the control unit 300 via the laser driving board 210. On the other hand, the laser driving board 210 illustrated in fig. 3 does not include a conversion circuit (which corresponds to the data conversion unit 312 illustrated in fig. 4) that converts image data for each scanning line in which the laser beam scans the photosensitive drum 102 into N pieces of PWM data corresponding to N LDs, respectively.

The connector 310a mounted in the laser driving board 210Y includes a terminal for outputting a BD signal to the control board 220 and four terminals for receiving data output from the control unit 300. A terminal for outputting a BD signal to the control board 220 is connected to the BD sensor 207Y. Four terminals for receiving data output from the control unit 300 are connected to four different terminals of the laser driver 200Y through print wirings, respectively. Note that connectors 309b, 309c, and 309d similar to the connector 309a are mounted on the control board 220. The connector 309b is configured to transmit and receive signals between the control unit 300 and the laser driving board 210M. The connector 309C is configured to transmit and receive signals between the control unit 300 and the laser driving board 210C. The connector 309d is configured to transmit and receive signals between the control unit 300 and the laser driving board 210K. In fig. 3, the connectors 309b, 309c, and 309d are not illustrated as including terminals for receiving BD signals, but they include terminals similar to the connector 309 a.

Image data received from an external PC or the like or image data generated by an original reading unit in the case where the image forming apparatus 100 includes the original reading unit is input into the image processing unit 301 inside the control board 220. The image data is, for example, PDL data. The image processing unit 301 performs predetermined image processing (color space conversion, gamma conversion, dither processing, and the like) on the input image DATA to generate Y, M, C and image DATA (DATA _ Y, DATA _ M, DATA _ C and DATA _ K) of each color of K. In this embodiment, a density value expressed by 5 bits per pixel is generated as image data for each color. The image processing unit 301 outputs the generated image data of each color to the data conversion unit 302.

The data conversion unit 302 operates in an operation mode according to the setting data output from the setting unit 304. The operation mode of the control unit 300 is determined in advance according to the configuration of the laser driving board 210, and a setting value indicating the first mode or the second mode is stored in the ROM 305. The setting unit 304 sets an operation mode according to a setting value stored in the ROM 305, and outputs setting data indicating the set operation mode to the data conversion unit 302. In fig. 3, a set value indicating the first mode is stored in the ROM 305. Accordingly, the data conversion unit 302 performs the operation of the first mode according to the setting data output from the setting unit 304. Note that the setting unit 304 uses the RAM306 as a temporary storage area.

The DATA conversion unit 302 converts the image DATA of Y color received from the image processing unit 301 into four PWM DATA corresponding to the four LDs (PWM DATA _ YA, PWM DATA _ YB, PWM DATA _ YC, and PWM DATA _ YD), respectively, and outputs the converted PWM DATA. These four PWM data are output from four output ports (YA1, YB1, YC1, and YD1) respectively corresponding to the four LDs to four corresponding input ports (YA2, YB2, YC2, and YD2) of the P/S conversion unit 303.

Here, fig. 5 illustrates an example of PWM data generated by the data conversion unit 302. The density value (density data) in fig. 5 is multi-valued data representing density gradation. On the other hand, the PWM data is binary data configured according to data for turning on the LD and data for turning off the light emitting element. The data conversion unit 302 converts 5-bit image data (density value) of one pixel into PWM data of one pixel in a parallel format of 40 bits according to the conversion pattern illustrated in fig. 5. Further, the data conversion unit 302 outputs 40-bit PWM data (parallel data) to the P/S conversion unit 303 by parallel transmission.

The P/S conversion unit 303 converts the data output from the data conversion unit 302 from a parallel format to a serial format for serial transmission, and transmits the converted data as control data to the laser driving board 210 via the connector 309a and a cable. Specifically, the P/S conversion unit 303 converts the four PWM DATA (PWM DATA _ YA, PWM DATA _ YB, PWMDATA _ YC, and PWM DATA _ YD) for the Y color into the PWM signals (PWM Signal _ YA, PWM Signal _ YB, PWM Signal _ YC, and PWM Signal _ YD) in the serial format, respectively. Further, the P/S conversion unit 303 transmits four PWM signals as converted serial data to the laser driving board 210Y via four cables from four output ports (YA3, YB3, YC3, and YD3), respectively.

In the laser driving board 210Y, the laser driver 200Y drives four LDs (LD _ A, LD _ B, LD _ C and LD _ D) according to four PWM signals received via four cables and the connector 310a, respectively. Thereby, the photosensitive drum 102Y is scanned in parallel by the N laser beams emitted from the four LDs, and an electrostatic latent image is formed on the photosensitive drum 102Y. Note that the data conversion unit 302 and the P/S conversion unit 303 also perform operations similar to the above-described operations on the M color, C color, and K color other than the Y color. Further, the laser driving boards 210M, 210C, and 210M perform similar operations to the laser driving board 210Y.

In fig. 3, only the laser drive board 210Y is shown as having the BD sensors 207Y arranged therein, but actually, BD sensors are arranged for each color in each laser drive board or in a board other than each laser drive board. Note that, depending on the configuration of the exposure unit 104, only the BD sensor 207Y may be configured in the laser driving board 210Y. The BD sensor 207Y outputs a signal for detecting a laser beam emitted from one LD (e.g., LD _ a) of the four LDs. The signal output from the BD sensor 207 is output from the laser driving board 210Y to the control board 220 by serial transmission, and is input into the S/P conversion unit 307. The S/P conversion unit 307 converts the input signal from a serial format to a parallel format, and outputs the converted signal to the BD detection unit 308. The BD detection unit 308 extracts a beam detection signal (BD signal) indicating detection of the laser beam from the input signal, and outputs the obtained BD signal to the data conversion unit 302. Thereby, the data conversion unit 302 generates four PWM data simultaneously with the BD signal.

< second mode operation >

Fig. 4 illustrates an example of the configuration of a control board 220 as a system controller of the image forming apparatus 100 of the present embodiment, and the configurations of laser drive boards 210Y, 210M, 210C, and 210K corresponding to Y, M, C and K, respectively, connected to the control board 220. Fig. 4 illustrates an operation of the case where the control board 220 is set to the second mode to match the configuration of the laser driving boards 210Y, 210M, 210C, and 210K.

The configuration of the control board 220 is the same for both the first mode and the second mode. In fig. 4, the S/P conversion unit 307 and the BD detection unit 308, which are not used in the second mode, are not illustrated, and a data transmission line, which is not used in the second mode, among data transmission lines between the data conversion unit 302 and the P/S conversion unit 303, is not illustrated. In fig. 4, a set value indicating the second mode is stored in the ROM 305. The setting unit 304 sets the second mode to the operation mode according to the setting value stored in the ROM 305, and outputs setting data indicating the set second mode to the data conversion unit 302. Thereby, the data conversion unit 302 performs the operation of the second mode according to the setting data output from the setting unit 304.

The operation of the image processing unit 301 is the same as that of the first mode explained using fig. 3. The DATA conversion unit 302 converts the image DATA (density DATA) of the Y color received from the image processing unit 301 into image DATA (LINE DATA _ Y) of a scanning LINE for scanning the photosensitive drum 102 with a laser beam, and outputs the converted DATA. Thereby, the data conversion unit 302 outputs the image data of the Y color to the P/S conversion unit in a state where the image data of the Y color is not converted into the PWM data. At this time, unlike the first mode, the data conversion unit 302 outputs the image data for each scan line to the P/S conversion unit 303 using one of four data transfer lines for the Y color between the data conversion unit 302 and the P/S conversion unit 303. In fig. 4, an example of a transmission line between one specific output port using the data conversion unit 302(YA1) and one corresponding input port using the P/S conversion unit 303(YA2) is illustrated.

The operation of the P/S conversion unit 303 is substantially the same as that of the first mode explained using fig. 3. However, only the operation corresponding to the input/output port being used is performed. Specifically, the P/S conversion unit 303 converts the image DATA (LINE DATA _ Y) for each scan LINE of the Y color into serial format DATA. Further, the P/S conversion unit 303 transmits the converted serial data from one output port (YA3) to the laser driving board 210Y via a terminal connected to the output port and a cable. That is, the control unit 300 outputs image data to the laser driving board 210Y from a common terminal regardless of which light emitting element the image data corresponds to.

In the laser driving board 210Y, four LDs (LD _ A, LD _ B, LD _ C and LD _ D) are driven based on image data of respective scanning lines received via one cable. Unlike the configuration of fig. 3, the laser driving board 210Y of fig. 4 includes an S/P converting unit 311Y, a data converting unit 312Y, P/S converting unit 313Y, S/P converting unit 317Y, and a BD detecting unit 318Y. These circuits (devices) are used to realize the functions of the control board 220 in fig. 3 on the laser driving board 210Y side. Note that in fig. 4, the connector on the laser driving board 210 is omitted due to the spatial relationship of the drawing.

The S/P conversion unit 311Y converts the image data of each scan line received from the control board 220 via one cable from a serial format to a parallel format, and outputs the converted data to the data conversion unit 312. The DATA conversion unit 312 converts the image DATA for each scan line of the Y color into four PWM DATA (PWM DATA _ YA, PWM DATA _ YB, PWM DATA _ YC, and PWMDATA _ YD) respectively corresponding to the four LDs by an operation similar to that of the DATA conversion unit 302 in the first mode, and outputs the converted PWM DATA.

The P/S conversion unit 313Y converts the four PWM DATA (PWM DATA _ YA, PWM DATA _ YB, PWM DATA _ YC, and PWM DATA _ YD) of the Y color into PWM signals (PWM Signal _ YA, PWM Signal _ YB, PWM Signal _ YC, and PWM Signal _ YD) of each serial format by an operation similar to the operation of the P/S conversion unit 303 in the first mode. Further, the P/S conversion unit 313Y outputs four PWM signals as converted serial data to the laser driver 200Y.

The laser driver 200Y drives four LDs (LD _ A, LD _ B, LD _ C and LD _ D) according to the four PWM signals output from the P/S conversion unit 313Y. Thereby, the photosensitive drum 102Y is scanned in parallel by the N laser beams emitted from the four LDs, and an electrostatic latent image is formed on the photosensitive drum 102Y. Note that the data conversion unit 302 and the P/S conversion unit 303 also perform operations similar to the above-described operations on the M color, C color, and K color other than the Y color. Further, the laser driving boards 210M, 210C, and 210M perform similar operations to the laser driving board 210Y.

Similar to the configuration of fig. 3, the laser driving board 210Y of fig. 4 includes a BD sensor 207Y. The BD sensor 207Y outputs a signal for detecting a laser beam emitted from one LD (e.g., LD _ a) of the four LDs. The S/P conversion unit 317 converts the output signal from the BD sensor 207Y from the serial format to the parallel format, and outputs the converted signal to the BD detection unit 318Y. The BD detection unit 318Y extracts a BD signal from the input signal and outputs the obtained BD signal to the data conversion unit 312Y and also to the control board 220.

Thereby, the data conversion unit 302 of the control board 220 generates image data for each scanning line simultaneously with the BD signal transmitted from the laser driving board 210Y. Further, the data conversion unit 312Y of the laser driving board 210Y generates four PWM data simultaneously with the BD signal output from the BD detection unit 318Y.

As described above, the control unit 300 of the present embodiment includes the setting unit 304 that sets the operation mode of the control unit 300, the data conversion unit 302 that operates according to the operation mode set by the setting unit, and the P/S conversion unit 303 for serial transmission. The setting unit 304 sets a first mode for generating PWM data representing a pattern for causing the LD to emit light from the image data and transmitting the generated PWM data to the laser driving board, or a second mode for transmitting the image data before the PWM data generation to the laser driving board. In the case where the first mode is set, the data conversion unit 302 converts the input image data into N PWM data corresponding to the N LDs, respectively, and outputs the converted data. On the other hand, in the case where the second mode is set, the data conversion unit 302 converts the input image data into image data for each scan line, and outputs the converted data. The P/S conversion unit 303 converts the data output from the data conversion unit 302 from a parallel format to a serial format for serial transmission, and outputs the converted data to the laser driving board 210 as control data.

The operation mode of the control unit 300 can be set to match the configuration of the laser driving board 210 connected to the control board 220. In this way, it becomes possible with the present embodiment to use the common control board 220 for the laser drive boards having different configurations mounted in the image forming apparatus 100. Therefore, the versatility of the control board 220 with respect to the laser driving board can be improved.

(modification example)

Fig. 6 is a modification of the laser driving board 210 illustrated in fig. 4. In fig. 4, it is illustrated that the S/P conversion circuit 311Y, the data conversion unit 312Y, and the P/S conversion circuit 313Y are mounted on the laser driving board 210Y as units different from the laser driver 200Y. However, as illustrated in fig. 6, the laser 600 (as a module) mounted in the laser driving board 220Y may include the S/P conversion circuit 311Y, the data conversion unit 312Y, and the P/S conversion circuit 313Y illustrated in fig. 4.

In addition, it is illustrated in fig. 4 and 6 that the laser driving board 210 drives a plurality of LDs, but the laser driving board 210 of fig. 4 and 6 may drive only one LD.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. An integrated circuit mounted on a control board of an image forming apparatus, the image forming apparatus comprising: an optical scanning device including a drive board on which a laser light source having a light emitting element that emits a light beam and a laser driver that drives the laser light source based on drive data are mounted, and the control board that transmits data to the drive board via a cable, characterized in that the integrated circuit includes:

a setting unit configured to set, as an operation mode, a first mode in which drive data representing a pattern for causing the light emitting elements to emit light is generated based on image data and transmitted to the drive board, and a second mode in which the image data is transmitted to the drive board without converting the image data into the drive data, wherein the drive data is binary data configured according to data for causing the light emitting elements to turn on and data for causing the light emitting elements to turn off, and the image data is multivalued data representing density gradation;

a data conversion unit configured to, in the first mode, convert input image data into drive data of the number of light emitting elements that the laser light source has and output the converted drive data to the drive board, and in a second mode, convert the input data into image data of each scan line in scanning of a photosensitive member by the light beam and output the converted image data; and

a transmission unit configured to continuously transmit the data output from the data conversion unit to the driving board.

2. The integrated circuit of claim 1, further comprising:

a memory configured to store a setting value representing the first mode or the second mode,

wherein the setting unit sets the operation mode according to a setting value stored in the memory.

3. The integrated circuit of claim 2,

setting values representing the first pattern are stored in the memory in a case where a drive board not including a conversion circuit that converts image data for each scanning line into N pieces of drive data is connected to the control board, and setting values representing the second pattern are stored in the memory in a case where a drive board including the conversion circuit that converts image data for each scanning line into N pieces of drive data is connected to the control board, the N being an integer greater than or equal to 2.

4. The integrated circuit of any of claims 1 to 3,

connecting the integrated circuit with drive boards that drive N light-emitting elements that respectively emit light beams that scan the photosensitive member, N being an integer greater than or equal to 2, and

in the first mode, the transmission unit transmits the N drive data to the drive board via N corresponding cables; and

in the second mode, the transmission unit transmits the image data for each scan line to the driving board via one cable.

5. The integrated circuit of any of claims 1 to 3,

connecting the data conversion unit and the transmission unit through N data transmission lines corresponding to N light emitting elements, N being an integer greater than or equal to 2, an

In the first mode, the data conversion unit outputs N driving data to the driving board using N corresponding data transmission lines; and

in the second mode, the data converting unit outputs image data for each scan line to the driving board using one of the N data transfer lines.

6. The integrated circuit of any of claims 1 to 3,

the driving board includes an optical sensor outputting a signal for detecting a light beam emitted from one of the N light emitting elements, and

in the first mode of operation,

the data conversion unit generates N drive data simultaneously with a detection signal representing detection of a light beam included in a signal output from the optical sensor and transmitted from the drive board, an

In the second mode of operation, the first mode of operation,

the data conversion unit generates image data for each scan line simultaneously with the detection signal transmitted from the driving board, an

The detection signal is generated in the driving board based on a signal output from the optical sensor and transmitted to the control board, and image data for each scanning line is converted into N pieces of driving data simultaneously with the detection signal by a conversion circuit of the driving board.

7. The integrated circuit of any of claims 1 to 3,

the integrated circuit is one integrated circuit including the setting unit, the data conversion unit, and the transmission unit.

8. The integrated circuit of any of claims 1 to 3,

connecting a plurality of driving boards formed for respective different color images with the control board, and

a data conversion unit converts image data for each input color into N drive data corresponding to the plurality of drive plates, respectively, and outputs the converted drive data in the first mode, and converts image data for each input color into image data for each scan line corresponding to each of the plurality of drive plates and outputs the converted image data in the second mode, and

the transmission unit converts data corresponding to each of the plurality of driving boards output from the data conversion unit from a parallel format to a serial format, and transmits the converted data to the corresponding driving board.

9. An integrated circuit mounted on a control board of an image forming apparatus, the image forming apparatus comprising: an optical scanning device including a drive board on which a laser light source having a light emitting element that emits a light beam and a laser driver that drives the laser light source are mounted, and the control board that transmits data to the drive board via a cable, characterized in that the integrated circuit includes:

a setting unit configured to set a first pattern of outputting drive data to the drive board and a second pattern of outputting density data to the drive board, wherein the drive data is binary data configured according to data to turn on the light emitting elements and data to turn off the light emitting elements, and the density data is multivalued data representing density gradation;

a data conversion unit configured to convert input image data into the drive data in the first mode, and to convert input image data into density data corresponding to each of a plurality of light emitting elements that the laser light source has mounted on the drive board in a second mode; and

a transmission unit configured to transmit the driving data converted by the data conversion unit to the driving board in the first mode, and transmit the density data corresponding to each of the plurality of light emitting elements converted by the data conversion unit to the driving board from the same output terminal in the second mode.

10. The integrated circuit of claim 9,

11. The integrated circuit of claim 9 or 10, further comprising:

wherein the setting unit sets the first mode or the second mode according to a setting value stored in the memory.