JP2013063540A - Optical scanning device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the accuracy of the total lighting time of a light source used in an optical scanning device.SOLUTION: A GAVD 310 or a CPU 320 calculates the lighting time of a semiconductor laser device 200 in an image formation area based on image data from a scanning device part 302. Also, the number of times of scanning of a laser beam L emitted from the semiconductor laser device 200 in a main scan direction is calculated and based on the number of times of the scanning and the previously set lighting time of the semiconductor laser device 200 per one scan in the area other than the image formation area, the lighting time of the semiconductor laser device 200 in the area other than the image formation area by the calculated number of times of the scanning is calculated. Then, the calculated lighting time of the semiconductor laser device 200 in the image formation area is added to the calculated lighting time of the semiconductor laser device 200 in the area other than the image formation area to obtain the total lighting time of the semiconductor laser device 200.

Description

  The present invention relates to an optical scanning device that deflects and scans a light beam from a light source, and a laser that forms an image (electrostatic image) by writing an image on the surface of an image carrier with the light beam deflected and scanned by the optical scanning device. The present invention relates to an image forming apparatus such as a printer, a digital copying machine, a facsimile machine (FAX), and a digital multifunction machine (MFP).

The image forming apparatus as described above includes an image forming process unit provided with respective units for charging, exposing, developing, and transferring around a photoconductor as an image carrier, and includes, for example, a series including the following image forming Image forming (hereinafter also referred to as “printing”) processing.
That is, first, the image forming region (surface) of the photosensitive member, which is a drum-like or belt-like image carrier that moves in the sub-scanning direction, is uniformly charged by the charging unit. The movement of the drum-shaped photosensitive member (rotating member) in the sub-scanning direction is also referred to as “rotating” or “rotating”. Further, the movement of a member (belt member) such as a belt-shaped photoconductor in the sub-scanning direction is also referred to as “turning”.

  Next, in an optical scanning device as an exposure unit, a light beam modulated in accordance with image data emitted from a light source is periodically used by deflecting means such as a rotary polygon mirror (hereinafter also referred to as “polygon mirror”). Deflection is performed, and the charged image forming area (charged surface) of the photosensitive member is repeatedly scanned (main scanning) in the main scanning direction orthogonal to the sub-scanning direction for exposure. As a result, an electrostatic image (also referred to as an “electrostatic latent image”) by a light beam is written on the charged surface of the photoreceptor. Then, the electrostatic image is developed with toner from the developing unit to form a toner image, and the transfer unit transfers the electrostatic image directly to a sheet as a recording medium, or transfers it onto an intermediate transfer belt and then transfers it to the sheet. The sheet on which the toner image is transferred is fixed to the toner image through the fixing unit and is discharged outside the apparatus.

On the other hand, in order to grasp the writing timing of the light beam in the main scanning direction, a synchronization detection signal is generated by a synchronization detection sensor as a synchronization detection means, and processing such as generation processing of a drive control signal to the light source is synchronized. This is called “synchronization detection”.
The light beam deflected by the deflecting unit is incident on the synchronization detection sensor, for example, immediately before the writing start position of the electrostatic image (or immediately after the writing end position) other than the image forming area of the photosensitive member. When the light beam is incident, the synchronization detection sensor outputs a synchronization detection signal.

Further, “auto power” automatically adjusts the light amount of the light source at a predetermined timing (for example, immediately after synchronization detection) so that the light amount of the light beam emitted from the light source (light amount of the light source) becomes a preset target value. Control (Auto Power Control: APC) ".
Furthermore, since unnecessary charges remain in the image forming area of the photoconductor after being transferred by the transfer unit, the residual charges are emitted from the light source of the optical scanning device at a predetermined timing (for example, at the end of one print job). "Light static elimination" is performed to eliminate the static electricity by exposure with a light beam.

  By the way, the light source of the optical scanning device as described above has a lifetime that is a lighting possible time until failure, for example, the lifetime of the semiconductor laser is longer than the lifetime of the image forming apparatus. Therefore, there are cases where only the semiconductor laser can be recycled (reused). When the semiconductor laser is recycled, it is necessary to determine whether or not the semiconductor laser can be recycled. For that purpose, it is important to grasp the lifetime of the semiconductor laser.

  Therefore, for example, as can be seen in Patent Document 1, lighting on / off data, which is image data for one main scanning line (hereinafter also simply referred to as “one line”), is counted for each pixel in order to determine the lifetime of the light source. There has been proposed an optical scanning device that performs (counting) and calculates the lighting time of the light source from the pixel count value.

In an image forming apparatus equipped with an optical scanning device, in order to perform the above-described synchronization detection, APC, light neutralization, etc., it is necessary to turn on the light source outside the image forming region.
However, for the calculation of the lighting time of the light source as described above, the lighting of the light source outside the image forming region, for example, the lighting of the light source for synchronous detection (synchronous lighting) or the lighting of the light source for APC (APC) Time calculation such as lighting (lighting) and lighting of the light source (lighting discharge) is not included.

Therefore, there is a problem that the accuracy of the total lighting time of the light source is lowered and the accuracy of the light source life determination is also lowered.
The present invention has been made in view of the above points, and an object thereof is to improve the accuracy of the total lighting time of a light source used in an optical scanning device.

  The present invention periodically deflects a light beam emitted from a light source based on image data using a deflecting unit, and forms an image forming area of an image carrier that moves in the sub-scanning direction in a direction orthogonal to the sub-scanning direction. An optical scanning apparatus that writes an image with a light beam in an image forming area by repeatedly scanning in a scanning direction. In order to achieve the above object, each means shown in the following (1) to (5) Is provided.

(1) First lighting time calculation means for calculating the lighting time of the light source in the image forming area based on the image data. (2) Information related to image formation of the image forming apparatus equipped with the optical scanning device is stored. Information storage means (3) scanning number calculation means for calculating the number of scans of the light beam in the main scanning direction based on the information relating to the image formation (4) the number of scans calculated in advance by the scanning number calculation means Second lighting for calculating the lighting time of the light source outside the image forming region for the calculated number of scans based on the set lighting time of the light source outside the image forming region per scan. Time calculation means (5) The lighting time of the light source in the imaging area calculated by the first lighting time calculation means and the imaging area other than the imaging area calculated by the second lighting time calculation means The total lighting time acquiring means for acquiring a total lighting time of the light source by adding the lighting time of the light source

  According to the optical scanning device of the present invention, the lighting time of the light source in the image forming area is calculated based on the image data. Further, the number of scans in the main scanning direction of the light beam emitted from the light source is calculated based on information relating to image formation of the image forming apparatus on which the optical scanning device is mounted. Further, based on the number of times of scanning and the lighting time of the light source outside the preset image forming area per scan, the lighting time of the light source outside the image forming area corresponding to the calculated number of scanning is calculated. Then, the total lighting time of the light source is obtained by adding the lighting time of the light source in the calculated imaging area and the lighting time of the light source outside the calculated imaging area. Therefore, the accuracy of the total lighting time of the light source is improved, and the accuracy of the light source life determination is also improved.

1 is a schematic diagram illustrating an example of a mechanical configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a perspective view showing a schematic configuration example of an optical system for exposing a photosensitive drum 104a in the optical scanning device 102 of FIG. FIG. 2 is a block diagram illustrating a schematic configuration example of a control unit of the image forming apparatus 100 illustrated in FIG. 1. FIG. 4 is a block diagram illustrating a configuration example of a function for calculating a total lighting time of each semiconductor laser element 200 in a region other than an image forming region by a main control unit 330 or GAVD 310 in FIG. 3. The rotation time of the main motor controlled by the I / O control unit 329 in FIG. 3, the sub-scanning gate signal FGATE indicating the effective image area in the sub-scanning direction of the printing paper generated by the GAVD 310, and each lighting state of the semiconductor laser element 200 It is a timing diagram which shows an example of a relationship. FIG. 4 is a block diagram illustrating a configuration example of a function of measuring the number of lines from the end of initialization lighting of the semiconductor laser element 200K to the image forming timing by the GAVD 310 and the main control unit 330 of FIG. 3.

Hereinafter, embodiments for carrying out the present invention will be described.
In the following embodiments, in order to determine the lifetime of a semiconductor laser (LD) that is a light source, the lighting time of the semiconductor laser is calculated in addition to the image forming area and also outside the image forming area.

Therefore, the above feature will be specifically described with reference to FIGS.
FIG. 1 is a schematic diagram illustrating an example of a mechanical configuration of an image forming apparatus according to an embodiment of the present invention.
The image forming apparatus 100 is an image forming apparatus such as a tandem digital color copying machine, a digital color multifunction peripheral, a color facsimile apparatus, and a color printer, and is configured as follows.

  That is, optical elements such as a semiconductor laser element 200 (see FIG. 2) for each color of black (K), cyan (C), magenta (M), and yellow (Y), which are a plurality of light sources, and a polygon mirror 102a. An optical scanning device 102 is included. In addition, a color image forming unit 112 including image forming process units 104, 106, 108, and 110 for K, C, M, and Y colors is also provided. Furthermore, a transfer unit 122 including an intermediate transfer belt 114 that is an endless transfer medium (endless moving member) is provided. That is, they constitute a color image forming unit (color image forming means).

  The image forming process units 104, 106, 108, and 110 of the color image forming unit 112 are drum-shaped photoconductors (hereinafter referred to as “photosensitive drums”) that are image carriers denoted by a, 104, 106, 108, and 110, respectively. 104a, 106a, 108a, 110a. Further, developing devices 104c, 106c, 108c, 110c, and d, which are developing means indicated by adding charging units 104b, 106b, 108b, 110b, c, which are charging means indicated by b arranged around them, are provided. Also provided are primary transfer rollers 104d, 106d, 108d, 110d, etc., which constitute transfer means.

  The optical scanning device 102 constitutes a post-object type optical scanning device that does not use an fθ lens, and the laser beam L that is a light beam emitted from each semiconductor laser element 200 is once temporarily associated with the first cylindrical beam. The light is collected by the lens 202 (see FIG. 2). Then, the light is deflected to the corresponding reflecting mirror 102b by the polygon mirror 102a (other deflecting means such as a vibrating mirror may be used).

  In this embodiment, the laser beams L deflected by the polygon mirror 102a are reflected by the corresponding reflecting mirrors 102b because of the numbers corresponding to the respective colors K, C, M, and Y, and by the corresponding second cylindrical lenses 102c. It is condensed again. Thereafter, image forming areas (hereinafter simply referred to as photosensitive drums 104a, 106a, 108a, 110a) that rotate in the sub-scanning direction of the respective image forming process units 104, 106, 108, 110 as a laser beam L used for exposure. The surface is also repeatedly scanned in the main scanning direction by the polygon mirror 102a and exposed.

Since the irradiation of the laser beam L onto the surfaces of the photosensitive drums 104a, 106a, 108a, and 110a is performed using a plurality of optical elements as described above, timing synchronization is performed in the main scanning direction and the sub-scanning direction. .
The “main scanning direction” is defined as the scanning direction of the laser beam L, and the “sub-scanning direction” is a direction orthogonal to the main scanning direction. In this image forming apparatus 100, the photosensitive drums 104a, 106a, 108a, 110a. Is defined as the direction of rotation, that is, the direction of movement of their surfaces.

Each of the photosensitive drums 104a, 106a, 108a, and 110a includes a photoconductive layer including at least a charge generation layer and a charge transport layer on a conductive drum such as aluminum.
Each of the photoconductive layers is uniformly charged by being given surface charges by chargers 104b, 106b, 108b, and 110b each composed of a corotron, a scorotron, a charging roller, or the like. The surfaces of the charged photoconductive layers of the photosensitive drums 104a, 106a, 108a, and 110a are imagewise exposed by the laser beam L from the optical scanning device 102, respectively, and are two-dimensional electrostatic latent images (electrostatic images). Is formed. In this embodiment, the electrostatic latent image and the toner image described later are formed in the order of Y, M, C, and K.

  The electrostatic latent images formed on the surfaces of the photosensitive drums 104a, 106a, 108a, and 110a are respectively developed by the developing devices 104c, 106c, 108c, and 110c including a developing sleeve, a developer supply roller, and a regulating blade. Development is performed with toner, which is a developer of each color of K, C, M, and Y, and a toner image (developed image) of each color is formed. The toner images of the respective colors face the primary transfer rollers 104d, 106d, 108d, and 110d, which are transfer means to which the photosensitive drums 104a, 106a, 108a, and 110a are respectively applied with a transfer bias voltage across the intermediate transfer belt 114. Are transferred onto the intermediate transfer belt 114 moving in the direction indicated by the arrow A in the order of Y, M, C, and K.

The intermediate transfer belt 114 is stretched around the transport rollers 114a, 114b, and 114c, and one of the intermediate transfer belts 114 is rotated in the direction indicated by the arrow A by the transport rollers 114a or 114c, which are driving rollers, and Y, M, C, and K toner images are formed. In a state where a full-color toner image that has been superimposed and transferred is carried, the toner image is conveyed to the secondary transfer unit.
The secondary transfer unit includes a secondary transfer belt 118 that is transported in the direction indicated by the arrow B by transport rollers 118a and 118b. The conveyance roller 114b of the intermediate transfer belt 114 also functions as a secondary transfer counter roller.

A sheet-like recording medium 124 such as high-quality paper or a plastic sheet is supplied to the secondary transfer unit from a recording medium storage unit 128 such as a paper feed cassette by a conveying roller 126. Then, a secondary transfer bias is applied to the conveyance roller 114 b that also functions as a secondary transfer counter roller, and the full-color toner image carried on the intermediate transfer belt 114 is held by suction on the secondary transfer belt 118. Transfer to the recording medium 124.
The recording medium 124 onto which the full-color toner image has been transferred is conveyed to the fixing device 120 by the rotation of the secondary transfer belt 118 in the arrow B direction.

The fixing device 120 is configured to include a fixing member 130 such as a fixing roller including silicone rubber or fluorine rubber, and pressurizes and heats the recording medium 124 together with the toner image to fix the toner image to the recording medium 124. After that, the printed matter 132 is discharged to the outside of the image forming apparatus 100.
After the toner image is transferred, the transfer residual toner is removed from the surface of the intermediate transfer belt 114 by a cleaning unit 116 including a cleaning blade, and the surface is prepared for the next image forming process.

Since unnecessary charges remain on the surfaces of the photosensitive drums 104a, 106a, 108a, and 110a after the toner image is transferred, the residual charges are generated at a predetermined timing (for example, at the end of one print job). The static electricity is removed by exposure with each laser beam L from the optical scanning device 102. This is referred to as “LD charge removal (light charge removal)” in this embodiment.
Further, the light quantity of each semiconductor laser element 200 is set at a predetermined timing so that the light quantity of the laser beam L emitted from each semiconductor laser element 200 (the light quantity of the semiconductor laser element 200) becomes a preset target value. Automatic adjustment (immediately after synchronization detection in this embodiment). This is called “APC”.

FIG. 2 is a perspective view showing a schematic configuration example of an optical system for exposing the photosensitive drum 104a in the optical scanning device 102 of FIG.
The laser beam L emitted from the K-color semiconductor laser element 200 (200K) is collected by the first cylindrical lens 202 used for shaping the laser beam bundle, and passes through the reflection mirror 204 and the imaging lens 206. After that, it is deflected by the polygon mirror 102a.
The polygon mirror 102a is rotationally driven by a spindle motor (not shown) that rotates several thousand to several tens of thousands.

The laser beam L reflected by the polygon mirror 102a is reflected by the K-color reflection mirror 102b and then reshaped by the second cylindrical lens 102c, and the surface of the photosensitive drum 104a is moved in the main scanning direction by the polygon mirror 102a. Exposure is repeated scanning.
In order to synchronize the writing timing of the laser beam L in the main scanning direction (also referred to as “main scanning image writing timing”), a reflection mirror 208 is disposed.

  The reflection mirror 208 is other than the image forming area in the main scanning direction of the photosensitive drum 104a (hereinafter also simply referred to as “other than the image forming area”), for example, before starting the scanning of the laser beam L in the main scanning direction (main scanning image writing). Just before the position), the laser beam L is reflected toward a synchronization detection device (synchronization detection sensor) 210 which is a synchronization detection means including a photodiode and the like, and is incident on the synchronization detection device 210 to be detected.

  When the synchronization detection device 210 (210K) detects the laser beam L, the synchronization detection device 210 (210K) serves as a reference for image writing control by the laser beam L in the main scanning direction in order to start main scanning of the laser beam L (main scanning image writing position). A synchronization detection signal (hereinafter also referred to as “tip synchronization detection signal”) is generated to synchronize processing such as generation of a drive control signal to the semiconductor laser element 200. This is called “synchronization detection”.

The semiconductor laser element 200 is driven by a pulse signal sent from a GAVD 310 (see FIG. 3) to be described later, and the laser beam L is exposed at a position corresponding to a predetermined image bit of image data (image information) as will be described later. Then, an electrostatic latent image is formed on the photosensitive drum 104a (image data is written by the laser beam L).
In addition, each part (except for the polygon mirror 102a) including the semiconductor laser element 200 and the synchronization detection device 210 described above is actually mounted for each color.

FIG. 3 is a block diagram illustrating a schematic configuration example of the control unit of the image forming apparatus 100 illustrated in FIG. 1.
This control unit is configured as a scanner unit 302, a printer unit 308, and a main control unit 330.
The scanner unit 302 reads an image of a document by performing a scanning process using an optical system including a solid-state imaging device such as a CCD color image sensor or a CMOS color image sensor. The scanner unit 302 includes a VPU (Video Processing Unit) 304 and an IPU (Image Processing Unit) 306.

The VPU 304 performs A / D conversion on the analog image signal output from the solid-state image sensor to acquire image data that is a digital image signal, and performs black offset correction, shading correction, and pixel position correction on the image data.
The IPU 306 performs image processing for digitally converting the image data from the VPU 304 as image data in the RGB color system to the CMYK color system. Note that “R” indicates red, “G” indicates green, and “B” indicates blue.

  The scanner unit 302 is communicably connected to the GAVD 310 via an image data interface (image data IF) 318. Therefore, when the image transfer request signal MFSYNC_N signal of each color is received from the GAVD 310 via the image data interface 318, the scan process can be started by the IPU 306. Further, the image data of each color subjected to image processing by the IPU 306 can be transmitted to the printer unit 308 via the image data interface 318.

The printer unit 308 includes a GAVD (Gate Array Video Driver) 310, LD drivers 312 (312K, 312C, 312M, 312Y) for each color, and the optical scanning device 102. The optical scanning device 102 includes a semiconductor laser element 200 (200K, 200C, 200M, 200Y) for each color and a synchronization detection device 210 (210K, 210C, 200M, 200Y).
When the GAVD 310 transmits an image transfer request signal MFSYNC_N signal of each color to the scanner unit 302 and receives image data of each color from the scanner unit 302, the GAVD 310 performs processing based on the image data of each color. That is, a drive control signal for performing drive control of each semiconductor laser element 200 via each LD driver 312 is generated.

Each LD driver 312 supplies a current for driving the corresponding semiconductor laser element 200 to the semiconductor laser element 200 by a drive control signal from the GAVD 310.
Each semiconductor laser element 200 is two-dimensionally arranged.
The scanner unit 302 and the printer unit 308 are connected to the main control unit 330 via the system bus 316, and image reading and image formation are controlled by commands from the main control unit 330.

The main control unit 330 includes a central processing unit (hereinafter referred to as “CPU”) 320 and a RAM 322 that provides a processing space used by the CPU 320 for processing.
The CPU 320 can be any CPU known so far, for example, CISC (Complex Instruction Set Computer) such as PENTIUM (registered trademark) series or compatible CPU, Reduced Instruction Set Computer (RISC) such as MIPS, etc. Can be used.

The CPU 320 expands the program stored in the ROM 324 in the RAM 322 at startup. After that, an instruction from the user (actually an operation unit not shown or an external device such as a personal computer not shown) is received from the RAM 322 via the interface 328, and a program for executing processing corresponding to the instruction is called from the RAM 322. Then, processing such as copying, facsimile, scanner, and image storage is executed.
Further, the main control unit 330 includes a ROM 324, and stores initial setting data, control data, programs, and the like of the CPU 320 so that the CPU 320 can use them.

The non-volatile memory 325 is a non-volatile storage unit that stores various data such as print information, which will be described later, and holds stored contents even when the power is turned off. As the nonvolatile memory 325, a nonvolatile RAM in which a backup circuit using a RAM and a battery is integrated, various nonvolatile memories such as an EEPROM and a flash memory can be used.
The image storage 326 is configured as a fixed or detachable memory device such as a hard disk device, an SD card, or a USB memory, stores image data acquired by the image forming apparatus 100, and can be used for various processes by the user. Yes.

In the I / O control unit 329, drive control of various motors including the above-described photosensitive drums 104a, 106a, 108a, 110a, the intermediate transfer belt 114, and the like, and a spindle motor that rotates the polygon mirror 102a, Detection is performed by various sensors.
Further, the color misregistration correction regarding the error deviation of the sub-scanning direction magnification (sub-scanning magnification) and the sub-scanning direction magnification (sub-scanning magnification) is performed by the I / O control unit 329 based on the correction amount. 106a, 108a, 110a and the motor speed of the conveying roller 114a are adjusted. In this embodiment, the conveyance roller 114 a functions as a driving roller for the intermediate transfer belt 114.

In the image forming apparatus 100 configured as described above, when the printer unit 308 is driven based on the image data from the scanner unit 302 to form an electrostatic latent image on the photosensitive drum 104a and the like and the image is output, the CPU 320 Performs position control in the main scanning direction and the sub-scanning direction of a recording medium such as high-quality paper and plastic film.
The CPU 320 outputs a start signal to the GAVD 310 when starting scanning in the sub-scanning direction on the document.

When the GAVD 310 receives a start signal from the CPU 320, the image transfer request signal MFSYNC_N signal of each color is output to the IPU 306 in the scanner unit 302 via the image data interface 318, so that the IPU 306 starts the scanning process.
After that, when receiving image data of each color from the IPU 306, the GAVD 310 stores them in a memory (not shown), processes the received image data of each color, generates a drive control signal, and outputs it to each LD driver 312. .

Each LD driver 312 generates a current for driving the semiconductor laser element 200 when receiving a drive control signal from the GAVD 310.
Thereafter, each LD driver 312 supplies the generated current to the semiconductor laser element 200 to turn on the semiconductor laser element 200.
Each LD driver 312 drives the semiconductor laser element 200 using pulse width modulation (PWM) control or power modulation (PM) control.

FIG. 4 is a block diagram showing a configuration example of a function for calculating the total lighting time of each semiconductor laser element 200 outside the image forming region by the main control unit 330 or GAVD 310 of FIG. Here, the recording medium is assumed to be printing paper (paper).
The main control unit 330 functions as a print information storage unit 501, a scan count calculation unit 502, a time calculation unit 503, and a time storage unit 504.

The print information storage unit 501 is an information storage unit that stores print information that is information related to printing (image formation). The print information refers to the number of printed sheets, the print paper size, the main motor rotation time, the number of print jobs, and the print pixel density (for example, pixel density in the sub-scanning direction) set in advance by a command from the user.
All of these pieces of print information are not necessarily required, and it is only necessary to have print information necessary for calculating the number of times of scanning and the lighting time of each semiconductor laser element 200 outside the image forming area described later.

The content of the print information varies depending on the lighting time calculation method.
In the case of the method of calculating the lighting time of each semiconductor laser element 200 outside the image forming area for each print job and finally calculating the total lighting time, the following is performed. In other words, information such as the number of printed sheets, print paper size, and print pixel density is updated to that for the print job each time a new print job is executed. The number of print jobs is updated by adding “1” each time a new print job is executed.

  In the case of a method of finally calculating the total lighting time without calculating the lighting time of each semiconductor laser element 200 outside the image forming area for each print job, the following is performed. That is, information for the print job is added each time a new print job is executed as information such as the number of printed sheets, print paper size, and print pixel density. The number of print jobs is updated by adding “1” each time a new print job is executed.

  The scan number calculation unit 502 receives each of the semiconductor laser elements 200 (200K, 200C, 200M, 200Y) based on the print information in the print information storage unit 501 for each print job or when a predetermined notification is received. It is a scanning number calculation means for calculating the number of times (scanning number) that the emitted laser beam L is scanned by the polygon mirror 102a.

  The time calculation unit 503 receives each scan count calculated by the scan count calculation unit 502 and a semiconductor other than a preset image forming area per scan when receiving a predetermined notification for each print job. Based on the lighting time of the laser element 200, second lighting time calculation means for calculating the lighting time of each semiconductor laser element 200 outside the imaging area corresponding to each of the calculated number of scans. The lighting time of each semiconductor laser element 200 outside the image forming area per scan includes a synchronous lighting time, an APC lighting time, and an LD charge-off lighting time, which will be described later.

  The time storage unit 504 calculates the lighting time of each semiconductor laser element 200 in an area other than the image forming area for each number of scans calculated by the time calculating section 503 (hereinafter also simply referred to as “other than the image forming area”). Each is a lighting time storage means for storing the lighting time of each semiconductor laser element 200 outside the calculated image forming area. The lighting time may be accumulated and stored for each print job, or may be stored as it is for each print job and accumulated later.

  Here, the print information storage unit 501 and the time storage unit 504 correspond to the nonvolatile memory 325 of FIG. Further, the functions as the scanning number calculation unit 502 and the time calculation unit 503, that is, the functions as the scanning number calculation unit and the second lighting time calculation unit can be realized by the CPU 320 executing a program. Alternatively, the GAVD 310 can be provided.

  Although not shown or described in detail because it is a well-known technique, the CPU 320 or GAVD 310 calculates the lighting time of each semiconductor laser element 200 in the image forming area based on the image data for each color for each print job. For example, the number of pixels of the image data for each color is counted (counted), and the lighting time of each semiconductor laser element 200 in the image forming area is calculated based on the counted number of pixels. The calculated lighting times may be accumulated for each print job and stored in the time storage unit 504, or may be stored as they are in the time storage unit 504 for each print job, and may be accumulated later.

Therefore, in the method of calculating the lighting time of each semiconductor laser element 200 outside the image forming region for each print job and finally calculating the total lighting time, the total lighting time of each semiconductor laser element 200 is set to the following. It can be obtained as follows.
That is, the lighting time of each semiconductor laser element 200 in the image forming area accumulated and stored for each print job in the time storage unit 504 and each semiconductor laser element other than the image forming area accumulated and stored for each print job 200 lighting times are added.

Alternatively, the lighting time of each semiconductor laser element 200 in the image forming area stored as it is for each print job in the time storage unit 504 and the lighting time of each semiconductor laser element 200 outside the image forming area stored as it is for each print job Are added to each other.
Alternatively, the total lighting time is added to the time storage unit 504 by adding the lighting time of each semiconductor laser element 200 in the image forming area and the lighting time of each semiconductor laser element 200 outside the image forming area for each print job. Remember. At this time, the total lighting time may be accumulated and stored for each print job, or may be stored as it is in the time storage unit 504 for each print job and accumulated later.

On the other hand, in the method of finally calculating the total lighting time without calculating the lighting time of each semiconductor laser element 200 outside the image forming area for each print job, the total lighting time of each semiconductor laser element 200 is calculated. It can be obtained as follows.
Based on the print information updated for each print job, the number of scans is calculated and stored in the nonvolatile memory 325 (corresponding to the scan number storage means) in FIG. 3 or stored as it is.

After that, for example, when the machine is finally collected, the following processing is performed by receiving a predetermined command from outside such as the operation unit (notifying that the machine has been collected). That is, based on the number of scans stored in the non-volatile memory 325 and the lighting time of each semiconductor laser element 200 other than the image formation area per scan, the image is recorded in a region other than the stored image formation region for the number of scans. The lighting time of each semiconductor laser element 200 is calculated and stored in the time storage unit 504.
To do.

The lighting time of each semiconductor laser element 200 in the image forming area accumulated and stored for each print job in the time storage unit 504, and each semiconductor laser element other than the image forming area for the number of scans stored above 200 lighting times are added.
Alternatively, the lighting time of each semiconductor laser element 200 in the image forming area stored as it is for each print job in the time storage unit 504 and the semiconductor laser elements 200 other than the image forming areas for the number of scans stored above. Add the lighting time respectively.

Furthermore, the semiconductor laser element 200 corresponding to the GAVD 310 can be turned on at the timing at which the laser beam L can be detected (detected) by each of the synchronization detection devices 210 (synchronization detection executable timing).
Furthermore, the APC can be performed by turning on the semiconductor laser element 200 corresponding to the GAVD 310 at the execution timing of the APC.
In addition, the semiconductor laser device 200 corresponding to the GAVD 310 can be turned on at the timing of executing the LD neutralization, and the LD neutralization can be performed.

Therefore, functions as first and second lighting time calculation means, scanning number calculation means, total lighting time acquisition means, first, second and third lighting control means, light amount adjustment means, static elimination means, and information update means Can be realized by the CPU 320 executing a program. Alternatively, the GAVD 310 can be provided.
Furthermore, each of the storage units and functions described above can be provided in the optical scanning device 102.

Next, the timing of each operation including the operation of the main motor, and the calculation of the lighting type and lighting time of the semiconductor laser element 200 will be described.
5 is a sub-scanning gate signal (sub-scanning direction of the laser beam L) indicating the rotation time of the main motor controlled by the I / O control unit 329 of FIG. 3 and the effective image area in the sub-scanning direction of the printing paper generated by the GAVD 310. FIG. 6 is a timing chart showing an example of the relationship between FGATE and each lighting state of the semiconductor laser element 200 (also serving as a sub-scanning image writing timing signal indicating the writing timing).

For convenience of explanation, the type of lighting of the semiconductor laser element 200 and the calculation of the lighting time thereof will be described only for the semiconductor laser element 200K for K color, but the semiconductor laser elements 200C and 200M for C, M, and Y are described. , 200Y, the description thereof will be omitted. In practice, the semiconductor laser element 200K is turned on to expose the surface of the photosensitive drum 104a to form an electrostatic latent image, which is developed with toner to form a toner image. A toner image is drawn on the printing paper (transfers the toner image). However, here, in order to make the explanation of the timing easy to understand, it is assumed that when the printing paper is conveyed to a predetermined position, the semiconductor laser element 200K is turned on (image lighting) is started.
Table 1 below shows the type of lighting at each operation timing.

(1) Immediately after the start of the main motor rotation In the image forming apparatus 100 of this embodiment, when the printing operation starts, the main motor for rotating various drive parts such as the transport roller 126 starts to rotate. Almost simultaneously with this timing, initialization lighting (LDD initialization lighting) of the semiconductor laser element (hereinafter also referred to as “LD”) 200K for initializing the LD driver (hereinafter also referred to as “LDD”) 312K in FIG. 3 starts. . Here, since the initialization lighting can be calculated from the type of the LD driver 312K and peripheral circuit constants, the lighting time (initialization lighting time) of the semiconductor laser element 200K is known in advance at the design stage. ms order.
Therefore, the total initialization time of the semiconductor laser element 200K can be calculated by multiplying the preset lighting time of the semiconductor laser element 200K by the number of print jobs.

(2) After completion of initialization lighting of the semiconductor laser element 200K until image formation timing (at start-up)
After the initialization lighting of the semiconductor laser element 200K is finished, the semiconductor laser element 200K is turned on synchronously (tip-synchronized lighting) and APC lighting is 1 line until the printing paper reaches a predetermined position and starts image formation. This is done once every or every few lines. The above-mentioned synchronous lighting is lighting of the semiconductor laser element 200K for detecting a tip synchronization detection signal for obtaining the main scanning image writing timing. The above APC lighting is lighting for adjusting the semiconductor laser element 200K to a target output.

In the example of FIG. 5, these lightings are illustrated separately, but may be performed simultaneously. The tip synchronous lighting and APC lighting per line are lighting whose lighting time is known in advance at the design stage because the lighting time can be calculated from the scanning time or pixel frequency of one line.
Therefore, if the number of lighting lines (number of scans) of the semiconductor laser element 200K can be calculated, the total lighting time in which the tip synchronous lighting and the APC lighting are performed can also be calculated.
The tip synchronous lighting and APC lighting are lighting performed continuously from (2) to (5). However, depending on the method of LD static elimination lighting, it may not be implemented in (5).

Here, the line number Lb from the end of the initialization lighting of the semiconductor laser element 200K to the image formation timing will be described.
FIG. 6 is a block diagram illustrating a configuration example of a function for measuring the number of lines from the end of the initialization lighting of the semiconductor laser element 200K by the GAVD 310 and the main control unit 330 in FIG. 3 to the image forming timing.

The main control unit 330 has functions as a main motor control unit 511, an image region control unit 512, and a measurement unit 513.
The main motor control unit 511 controls the main motor, and outputs a signal (main motor ON / OFF signal) for turning the main motor on (ON) / off (OFF) to the main motor and the measurement unit 513. . The function as the main motor control unit 511 is included in the I / O control unit 329 in FIG.

The image area control unit 512 controls the image area (image forming area), generates a sub-scanning gate signal (also serving as a sub-scanning image writing timing signal) FGATE, and outputs it to the measurement unit 513. The GAVD 310 in FIG. 3 has the function as the image area control unit 512.
The measuring unit 513 is based on the main motor ON / OFF signal from the main motor control unit 511 and the sub-scanning gate signal FGATE from the image area control unit 512, and after the completion of initialization lighting of the semiconductor laser element 200K until the image forming timing. Is measured using a counter (not shown). The function as the measurement unit 513 can be realized by the CPU 320 executing a program.

As described above, the initialization lighting of the semiconductor laser element 200K starts almost simultaneously with the start of the rotation of the main motor, but since the initialization lighting ends, it is in the order of us to several ms. The start of rotation and the end of initialization lighting can be considered almost simultaneously.
The time from the start of rotation of the main motor to the assertion of the sub-scanning gate signal (sub-scanning image writing timing signal) FGATE can be considered as the time from the end of initialization lighting of the semiconductor laser element 200K to the image formation timing.

Therefore, the number of lines Lb from the end of initialization lighting of the semiconductor laser element 200K to the image forming timing can be calculated by the scanning number calculation unit 502 of FIG.
Lb [mm] = {(Time from start of main motor rotation to FGATE assertion [s]
× A [mm / s]) / 25.4 [mm]} × B [dpi]
A = Line speed [mm / s]
B = Sub-scanning pixel density [dpi (dots / inch)]
1 [inch] = 25.4 [mm]

  If the semiconductor laser element 200K has a multi-beam configuration in which a plurality of laser beams (multi-beams) are emitted, a plurality of lines may be turned on simultaneously in one scan, so that division is also necessary in consideration of the number of beams. It is. For example, in the case of two-beam simultaneous scanning (simultaneous two-line scanning), a numerical value obtained by dividing the calculated number of lines Lb by the number of beams is the number of lines lit per one beam.

(3) During image formation, (4) Between papers During image formation, the lighting time (image lighting time) of the semiconductor laser element 200K in the image forming area (portion where the toner image is drawn on the printing paper) is a well-known pixel count function. Calculate using. That is, the CPU 320 in FIG. 3 reads image data for one line from the GAVD 310, counts the image data for each pixel using a counter (not shown), and counts the number of pixels. A 200K image lighting time is calculated.
The time for leading edge synchronous lighting and APC lighting can be obtained by calculating the number of lines from the size of the printing paper in the sub-scanning direction.
Since the inter-paper distance is determined at the design stage, the number of lines can be calculated.

The number Lc of lines between the image forming and the paper is calculated by the following equation.
Number Lc [mm] = Number of pixels in the sub-scanning direction [dot]
= [{C [mm] × E [sheets] + D [mm] × (E [sheets] −1 [sheets])}
/25.4 [mm]] × B [dpi]
C = size of printing paper in the sub-scanning direction [mm]
D = Paper spacing [mm]
E = Number of printed sheets [sheets]

(5) At the time of static elimination from LD
The LD charge removal is usually performed by causing the semiconductor laser element 200K to turn on about the photosensitive drum 104a1 rotation + α.
As a method for performing LD charge removal, there are methods shown in the following (a) and (b).
(A) Method of keeping the semiconductor laser element 200K in a forced lighting state and continuing lighting for a predetermined time (b) Method similar to drawing a pattern (see FIG. 5)

Method (a) Disregarding tip synchronous lighting and APC lighting, the semiconductor laser element 200K is kept on and the lighting time is determined in advance, so the total lighting time for LD static elimination is calculated by multiplying the number of jobs. it can.
Method (b) There are two types of pattern part calculation methods.
1. Since the lighting time of the semiconductor laser element 200K in the pattern portion at the time of performing the LD neutralization is determined in advance, it is obtained by multiplying the number of jobs.
2. The pattern portion is calculated using a known pixel count function.

The number of lines Ld for calculating the time of tip synchronous lighting and APC lighting is obtained by the following equation.
Number of lines Ld [mm] = [{F [mm] + (α [ms] × A [mm / s])}
/25.4 [mm]] × B [dpi]
F = around photosensitive member 104a [mm]
α = plus α lighting time [s]

In order to correct the magnification of the image data in the main scanning direction, synchronization detection may be performed on the rear end side of the main scanning direction to generate a synchronization detection signal (rear end synchronization detection signal). Since the lighting time of the semiconductor laser element 200K in this case (rear end synchronized lighting) can be calculated in the same manner as in the case where the front end synchronized lighting is performed as described above, description thereof is omitted.
In addition, if the time of synchronous lighting and APC lighting is simply calculated, the number of lines within the time may be calculated from the rotation time of the main motor by the following equation.
Number of lines = {(main motor rotation time [s] × A [mm / s])
/25.4 [mm]} × B [dpi]

Further, the calculation method of each lighting time described above may be the following method, but may be performed at any time as long as the operation does not cause a problem.
(A) Method of calculating, storing and integrating at the end of each job (B) Accumulating time from the start of main motor rotation to FGATE assertion, integrating the number of lines, integrating the number of jobs, Method to calculate when the machine is finally collected

As described above, in the image forming apparatus of this embodiment, the lighting time of the semiconductor laser element 200 in the image forming area is calculated based on the image data. Further, the number of scans in the main scanning direction of the laser beam emitted from the semiconductor laser element 200 is calculated based on the print information (information relating to image formation). Further, based on the number of times of scanning and the lighting time of the semiconductor laser element 200 outside the image forming area per scan set in advance, the semiconductor laser element 200 is turned on outside the image forming area corresponding to the calculated number of scans. Calculate time. Then, the total lighting time of the semiconductor laser element 200 is obtained by adding the lighting time of the semiconductor laser element 200 in the calculated image forming area and the lighting time of the semiconductor laser element 200 outside the calculated image forming area. .
Therefore, the accuracy of the total lighting time of the semiconductor laser element 200 is improved, and the accuracy of determining the lifetime of the semiconductor laser element 200 is also improved.

  As described above, the present invention is applied to an indirect transfer type image forming apparatus in which the toner images of the respective colors are sequentially transferred from the respective photoreceptors onto the intermediate transfer belt and then transferred to the recording medium. Although the embodiment has been described, the present invention is not limited to this. That is, the present invention can be applied not only to a direct transfer type image forming apparatus that directly transfers a toner image of each color from each photoconductor to a recording medium, but also to other types of image forming apparatuses. Alternatively, the present invention can also be applied to a monochromatic image forming apparatus such as monochrome, or an image forming apparatus having two or three colors.

In an image forming apparatus with a small P / J (number of printed sheets per job) such as a low-speed machine, lighting outside the image forming area becomes important (dominant). Is big.
Further, the present invention is not limited to the above-described embodiment, and it goes without saying that all the technical matters included in the technical idea described in the claims are covered.

100: Image forming apparatus 102: Optical scanning apparatus 102a: Polygon mirrors 102b, 204, 208: Reflection mirror 102c: Second cylindrical lenses 104, 106, 108, 110: Image forming process units 104a, 106a, 108a, 110a: Photoconductor Drum 104b, 106b, 108b, 110b: charger 104c, 106c, 108c, 110c: developing device 112: color image forming unit 114: intermediate transfer belt 114a, 114b, 114c: transport roller 118: secondary transfer belt 120: fixing device 122: transfer unit 124: recording medium 130: fixing member 132: printed matter 200 (200K, 200C, 200M, 200Y): semiconductor laser element 202: first cylindrical lens 206: imaging lens 210 (210K, 210C, 210M, 21) 0Y): synchronization detection device 302: scanner unit 304: VPU 306: IPU 308: printer unit 310: GAVD
312 (312K, 312C, 312M, 312Y): LD driver 320: CPU
322: RAM 324: ROM 325: Non-volatile memory 326: Image storage 328: Interface 329: I / O control unit 330: Main control unit 501: Print information storage unit 502: Scan count calculation unit 503: Time calculation unit 504: Time Storage unit 511: Main motor control unit 512: Image area control unit 513: Measurement unit

Japanese Unexamined Patent Publication No. 2000-180764

Claims (7)

The light beam emitted from the light source is periodically deflected using the deflecting means based on the image data, and the image forming area of the image carrier that moves in the sub-scanning direction is repeated in the main scanning direction orthogonal to the sub-scanning direction. An optical scanning device that writes an image with a light beam in the image forming region by scanning,
First lighting time calculation means for calculating a lighting time of the light source in the image forming area based on the image data;
Information storage means for storing information relating to image formation of an image forming apparatus equipped with the optical scanning device;
A scanning number calculation means for calculating the number of scanning times of the light beam in the main scanning direction based on the information relating to the image formation;
Based on the number of scans calculated by the number-of-scans calculation unit and a preset lighting time of the light source outside the image forming area per one scan, except for the calculated image forming area for the number of scanning times. Second lighting time calculation means for calculating the lighting time of the light source;
The lighting time of the light source in the image forming area calculated by the first lighting time calculating means and the lighting time of the light source outside the image forming area calculated by the second lighting time calculating means. An optical scanning device comprising: a total lighting time acquisition means for adding and acquiring the total lighting time of the light source. The optical scanning device according to claim 1,
Synchronization detecting means for detecting the light beam scanned in the main scanning direction outside the image forming region, and generating and outputting a synchronization detection signal serving as a reference for image writing control by the light beam;
Providing a first lighting control means for lighting the light source at a timing at which the light beam can be detected by the synchronization detection means;
The light scanning device in which the lighting time of the light source outside the image forming area per scan is the lighting time of the light source by the first lighting control means. The optical scanning device according to claim 1,
A light amount adjusting means for adjusting the light amount of the light source so that the light amount of the light source becomes a preset target value;
A second lighting control unit for lighting the light source at a timing when the light amount adjustment of the light source is performed by the light amount adjusting unit;
The lighting time of the light source outside the image forming area per scan is a lighting time of the light source by the second lighting control means. The optical scanning device according to claim 1,
Neutralizing means for exposing and neutralizing the image forming area of the image carrier by scanning with the light beam;
A third lighting control means for lighting the light source at a timing when the static elimination is performed by the static elimination means;
An optical scanning device characterized in that the lighting time of the light source outside the image forming area per scan is the lighting time of the light source by the third lighting control means.   5. An optical scanning device according to claim 1, and an image carrier having an image forming region in which the optical beam is scanned by the optical scanning device, and using the optical scanning device, the optical scanning device. An image forming apparatus, wherein an image is written by a light beam in an image forming region of an image carrier to form an image on a recording medium. The image forming apparatus according to claim 5.
Providing an information updating means for updating the information relating to image formation to information for a new image forming job for each image forming job;
The first lighting time calculating means is means for calculating a lighting time of the light source in the image forming area for each image forming job.
The number-of-scanning calculating means is means for calculating the number of times the light beam is scanned in the main scanning direction based on information relating to the image formation updated by the information updating means for each image forming job;
The second lighting time calculation unit is a unit that calculates a lighting time of the light source outside the image forming area for each image forming job.
The total lighting time acquisition means is calculated by the lighting time of the light source in the image forming area calculated by the first lighting time calculation means and the second lighting time calculation means for each image forming job. A means for obtaining a total lighting time of the light source by adding a lighting time of the light source outside the image forming area,
For each image forming job, the lighting time of the light source in the imaging area calculated by the first lighting time calculation means and the imaging area other than the imaging area calculated by the second lighting time calculation means. An image forming apparatus comprising: a lighting time storage unit that stores a lighting time of the light source or a total lighting time of the light source acquired by the total lighting time acquisition unit. The image forming apparatus according to claim 5.
As information related to the image formation, information for a new image formation job is added for each image formation job, and information update means for updating the number of image formation jobs is provided,
The first lighting time calculating means is means for calculating a lighting time of the light source in the image forming area for each image forming job.
The number-of-scanning calculating means is means for calculating the number of times the light beam is scanned in the main scanning direction based on information relating to the image formation updated by the information updating means for each image forming job;
Lighting time storage means for storing the lighting time of the light source in the imaging area calculated by the first lighting time calculation means for each image forming job;
Scanning number storage means for storing the number of scanning times calculated by the scanning number calculation means for each image forming job;
The second lighting time calculation means is based on the number of scans stored in the scan number storage means and the lighting time of the light source outside the image forming area per one scan in response to a predetermined notification from the outside. And means for calculating a lighting time of the light source outside the image forming area corresponding to the stored number of scans,
The total lighting time acquisition means is calculated by the lighting time of the light source in the image forming area stored in the lighting time storage means and the second lighting time calculation means by the predetermined notification from the outside. An image forming apparatus characterized in that the total light-on time of the light source is obtained by adding the light-on time of the light source outside the image forming area for the stored number of scans.

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