JP6740796B2 - Information processing device, pixel setting method, and program - Google Patents

Description

The present invention relates to an information processing device, a pixel setting method, and a program.

An image forming apparatus that prints and forms an image on recording paper includes a light source that emits light for forming a latent image on a photosensitive drum or the like, and an information processing apparatus that controls the light source. In such an information processing apparatus, the light amount of the light source is switched off, normal exposure, and strong exposure stronger than normal exposure in order to cope with thinning of an image and the like. The information processing device supplies an overshoot current and an undershoot current to the light source in order to improve the rising and falling characteristics of the current for driving the light source.

However, since the normal exposure current and the strong exposure current change greatly depending on the process conditions and the passage of time, there is a large deviation from the ideal values of the overshoot current and the undershoot current, and the overshoot current and the undershoot current can be accurately measured. There is a problem that it is difficult to correct.

The present invention has been made in view of the above, and relates to an information processing device, a pixel setting method, and a program that can easily correct an overshoot current and an undershoot current.

In order to solve the above-mentioned problems and achieve the object, the information processing apparatus according to the present invention is configured such that a first light source emits light for forming a latent image according to a first image based on first image data. A region including the first pixel, which is in contact with a boundary between a first pixel which is a pixel irradiated with a light amount and a second pixel which is a pixel irradiated with a second light amount stronger than the first light amount A first detection unit that detects a first boundary area; and a first pixel in the first boundary area, which is converted into an extinguished pixel that is a pixel in which the light source is extinguished, to convert the first pixel and the second pixel. It is converted by the post-processing unit using the post-processing unit for arranging the extinguished pixel in between, the overshoot current supplied to the rising of the current supplied to the light source, and the undershoot current supplied to the falling of the current. And a light source drive unit for switching the light amount of the light emitted by the light source according to the first image data to the first light amount, the second light amount, and turning off the light source to drive the light source.

According to the present invention, it is possible to accurately correct the overshoot current and the undershoot current.

FIG. 1 is an overall configuration diagram of the image forming apparatus according to the embodiment. FIG. 2 is a top view showing the configuration of the optical system of the optical scanning unit. FIG. 3 is a side view showing the configuration of the optical system of the optical scanning unit. FIG. 4 is a diagram showing the configuration of an information processing device that controls the optical scanning unit. FIG. 5 is a block diagram showing the hardware configuration of the interface unit. FIG. 6 is a functional block diagram showing the configuration of the image processing unit. FIG. 7 is a diagram of a schematic configuration of the drive control unit. FIG. 8 is a block diagram illustrating the function of the light source modulation data generation unit. FIG. 9 is a block diagram illustrating the function of the light source driving unit. FIG. 10 is a diagram showing the relationship between the drive current flowing through the light source and the control signal. FIG. 11 is a diagram illustrating the first image processing. FIG. 12 is a diagram showing conversion of the light amount in the first image processing of FIG. FIG. 13 is a diagram illustrating the second image processing after the first image processing. FIG. 14 is a diagram showing conversion of the light amount in the second image processing of FIG. FIG. 15 is a flowchart of the light amount adjustment process. FIG. 16 is a diagram for explaining the timing of light amount adjustment. FIG. 17 is a flowchart of a pixel setting process performed by the drive control unit of the information processing device.

Similar reference numerals are given to similar components in the following exemplary embodiments and the like, and redundant description will be appropriately omitted.

<Embodiment>
FIG. 1 is an overall configuration diagram of an image forming apparatus 10 of the embodiment. As shown in FIG. 1, the image forming apparatus 10 includes a housing 12, a paper feeding unit 14, an optical scanning unit 16, a plurality of image forming stations 18K, 18C, 18M and 18Y, a transfer unit 20, and a fixing unit. A roller 21, a density detector 22, a communication controller 24, and a printer controller 26 are provided. When it is not necessary to distinguish the image forming stations 18K, 18C, 18M, and 18Y, they are referred to as the image forming station 18.

The housing 12 has a hollow shape. The housing 12 houses, for example, a paper feeding unit 14, an optical scanning unit 16, a plurality of image forming stations 18, a transfer unit 20, a fixing roller 21, a density detection unit 22, a communication control unit 24, and a printer control device 26. To do. A part of the upper surface of the housing 12 functions as a paper discharge tray 12a for discharging the printed recording paper.

The paper feed unit 14 has a paper feed tray 14a and a paper feed transport unit 14b. The paper feed tray 14a stores recording paper before printing. The paper feed/conveyance unit 14 b feeds the recording paper in the paper feed tray 14 a to the transfer unit 20.

The optical scanning unit 16 scans and irradiates the photoconductor drum 34 of the image forming station 18 described later with light to form a latent image on the surface of the photoconductor drum 34 that rotates in a charged state.

The number of image forming stations 18K, 18C, 18M, and 18Y is determined according to the number of colors to be printed, and is four, for example. The image forming stations 18K, 18C, 18M, and 18Y form images of different colors (for example, black, cyan, magenta, and yellow).

Each image forming station 18 includes a charging unit 28, a toner cartridge 30, a developing roller 32, a photosensitive drum 34, a cleaning unit 36, and a position detecting unit 38.

The charging unit 28 is provided near the surface of the photosensitive drum 34. The charging unit 28 uniformly charges the surface of the rotating photosensitive drum 34.

The toner cartridge 30 stores toner. The toner cartridge 30 uniformly applies toner to the surface of the developing roller 32.

The developing roller 32 supplies the toner applied to the surface to the photosensitive drum 34 while rotating. As a result, the developing roller 32 forms a toner image on the photosensitive drum 34 by developing the latent image on the surface of the photosensitive drum 34 with the toner.

The photoconductor drum 34 carries a latent image formed on its surface by being irradiated with light by the light scanning unit 16 in a charged state. The surface of the photoconductor drum 34 holds a toner image formed by supplying toner while carrying a latent image. The photoconductor drum 34 transfers the toner image onto a transfer belt 44 of the transfer unit 20 described later. The central axis direction of the photosensitive drum 34 (that is, the Y direction) is referred to as the "main scanning direction". The X direction is referred to as the "sub-scanning direction".

The cleaning unit 36 removes the toner remaining on the surface of the photosensitive drum 34 after the transfer onto the transfer belt 44.

The position detector 38 detects the home position (that is, the reference position) of the photosensitive drum 34 in the rotation direction.

The transfer unit 20 includes a plurality of (for example, three) rotating rollers 40, a transfer roller 42, and a transfer belt 44.

The plurality of rotation rollers 40 rotate while applying tension to the transferred transfer belt 44.

The transfer roller 42 presses the transfer belt 44 onto the recording paper fed from the paper feeding unit 14.

The transfer belt 44 is rotated by the rotating roller 40 while being in contact with the photosensitive drum 34. As a result, the toner image is transferred from the photosensitive drum 34 to the transfer belt 44. The transfer belt 44 transfers the toner image onto the recording paper pressed by the transfer roller 42.

The fixing roller 21 applies heat and pressure to the toner image transferred to the recording paper to fix the toner image on the recording paper and print it. The fixing roller 21 discharges the recording paper on which the toner image is fixed to the paper discharge tray 21a.

The density detector 22 detects the density of the toner image transferred to the transfer belt 44.

The communication control unit 24 controls bidirectional communication between the higher-level device 99 such as an external computer connected via a network and the printer control device 26.

The printer control device 26 controls overall control of the image forming apparatus 10. The printer control device 26 includes a CPU (Central Processing Unit), a ROM that stores a program described by a code executed by the CPU and various data used when the program is executed, a RAM that is a working memory, It has an AD conversion circuit and the like for converting analog data into digital data. The printer control device 26 controls each unit in response to a request from the host device 99, and sends the image data from the host device 99 to the optical scanning unit 16.

FIG. 2 is a top view showing the configuration of the optical system of the optical scanning unit 16. FIG. 3 is a side view showing the configuration of the optical system of the optical scanning unit 16. As shown in FIGS. 2 and 3, the optical scanning unit 16 includes a plurality of light source units 46K, 46C, 46M, 46Y and a scanning unit 48. When it is not necessary to distinguish the light source units 46K, 46C, 46M, and 46Y, the light source units 46 will be referred to.

The number of light source units 46K, 46C, 46M, and 46Y is four, which is the same as the number of image forming stations 18, that is, the number of colors to be printed. Each light source unit 46 is associated with one of the image forming stations 18. Specifically, the light source units 46K, 46C, 46M, and 46Y irradiate the photoconductor drums 34 of the image forming stations 18K, 18C, 18M, and 18Y with light. The light source unit 46 includes a light source 50, a coupling lens 52, an aperture plate 54, and a cylindrical lens 56.

The light source 50 has an array structure in which a plurality of light emitting elements are two-dimensionally arranged at equal intervals. An example of the light emitting element is a surface emitting laser such as a vertical cavity surface emitting laser (VCSEL: Vertical Cavity Surface Emitting LASER). The light source 50 irradiates the coupling lens 52 with light (for example, laser light).

The coupling lens 52 is arranged on the optical path of the light emitted from the light source 50. The coupling lens 52 irradiates the aperture plate 54 with the light from the light source 50 as parallel light.

The aperture plate 54 is arranged on the optical path of the parallel light emitted from the coupling lens 52. An opening is formed in the opening plate 54. The aperture plate 54 shapes the parallel light from the coupling lens 52 by the aperture and irradiates the cylindrical lens 56.

The cylindrical lens 56 is arranged on the optical path of the light shaped by the aperture plate 54. The cylindrical lens 56 forms an image on the reflecting surface of the polygon mirror 58 of the scanning unit 48 described later.

The scanning unit 48 has a polygon mirror 58, scanning lenses 60a, 60b, 60c and 60d, and folding mirrors 62a, 62b, 62c, 62d, 62e and 62f.

The polygon mirror 58 is arranged on the optical path of the light emitted from the light source unit 46. The polygon mirror 58 is rotatably supported around the Z axis. The polygon mirror 58 has two sets of mirror surface members 58a and 58b having four mirror surfaces that function as deflecting/reflecting surfaces. The mirror surface member 58a reflects the light of the light source units 46K and 46Y to the scanning lenses 60a and 60d, respectively. The mirror surface member 58b reflects the light of the light source units 46C and 46M to the scanning lenses 60b and 60c, respectively. Here, the polygon mirror 58 moves the reflection direction of the light from the light source unit 46 by rotating the mirror surface members 58a and 58b around the Z axis. As a result, the polygon mirror 58 scans the photosensitive drum 34 with light.

The scanning lens 60a and the folding mirror 62a are arranged on one side (the -X direction side) of the reflection direction of the mirror surface member 58a. The scanning lens 60a guides the light emitted by the light source unit 46K and reflected by the polygon mirror 58 to the folding mirror 62a. The folding mirror 62a reflects the light from the scanning lens 60a to the photosensitive drum 34 of the image forming station 18K.

The scanning lens 60b and the folding mirrors 62b and 62c are arranged on one side (the -X direction side) of the reflection direction of the mirror surface member 58b. The scanning lens 60b guides the light emitted by the light source unit 46C and reflected by the polygon mirror 58 to the folding mirror 62b. The folding mirrors 62b and 62c reflect the light from the scanning lens 60b to the photosensitive drum 34 of the image forming station 18C.

The scanning lens 60c and the folding mirrors 62d and 62e are arranged on the other side (+X direction side) in the reflection direction of the mirror surface member 58b. The scanning lens 60c guides the light emitted by the light source unit 46M and reflected by the polygon mirror 58 to the folding mirror 62d. The folding mirrors 62d and 62e reflect the light from the scanning lens 60c to the photosensitive drum 34 of the image forming station 18M.

The scanning lens 60d and the folding mirror 62f are arranged on the other side (+X direction side) in the reflection direction of the mirror surface member 58a. The scanning lens 60d guides the light emitted by the light source unit 46Y and reflected by the polygon mirror 58 to the folding mirror 62f. The folding mirror 62f reflects the light from the scanning lens 60d to the photosensitive drum 34 of the image forming station 18Y.

Here, as the polygon mirror 58 rotates, the direction of light moving on the photoconductor drum 34 is the main scanning direction. The main scanning direction is the central axis direction of the photosensitive drum 34 and is the Y direction.

The folding mirrors 62a, 62b, 62c, 62d, 62e, 62f are arranged so that the optical paths from the polygon mirror 58 to the photosensitive drum 34 are substantially equal.

FIG. 4 is a diagram showing the configuration of the information processing device 63 that controls the optical scanning unit 16. As shown in FIG. 4, the information processing device 63 of the optical scanning unit 16 includes an interface unit 64, an image processing unit 66, and a drive control unit 68.

The interface unit 64 acquires the image data transmitted from the higher-level device 99 from the printer control device 26. The interface unit 64 sends the image data to the image processing unit 66. The interface unit 64 transmits the image data of the RGB format, the resolution of 1200 dpi, and the bit number of 8 bits to the image processing unit 66, for example.

The image processing unit 66 converts the image data acquired from the interface unit 64 into image data compatible with the printing method. For example, the image processing unit 66 converts the RGB format image data into image data having a tandem format (CMYK format), a resolution of 2400 dpi (=first resolution) and a bit number of 1 bit. The image processing unit 66 generates tag information indicating whether the pixel data included in the image data is a character or a line. The image processing unit 66 transmits the generated image data to the drive control unit 68.

The drive control unit 68 is a one-chip integrated circuit provided near the light source unit 46. The drive control unit 68 is arranged farther from the light source unit 46 than the interface unit 64 and the image processing unit 66. The drive control unit 68 is connected to the image processing unit 66 by a cable.

The drive control unit 68 converts the image data including the tag information acquired from the image processing unit 66. For example, the drive control unit 68 converts the resolution of the image data to increase it. Specifically, the drive control unit 68 converts the image data having a tandem format (CMYK format), a resolution of 2400 dpi and a bit number of 1 bit into a tandem format (CMYK format), a resolution of 4800 dpi (=second resolution, second resolution). Is higher than the first resolution) and image data having a bit number of 1 bit.

The drive control unit 68 modulates the converted image data into a clock signal indicating the light emission timing, and colors (that is, the photoconductor drums 34 of the image forming stations 18K, 18C, 18M, and 18Y and the light source units 46K and 46C). , 46M, 46Y) and independent modulation signals are generated. The drive control unit 68 independently controls the light sources 50 of the light source units 46K, 46C, 46M, and 46Y to emit light based on the generated modulation signal. The drive control unit 68 may integrally perform resolution conversion and generation of a modulation signal.

FIG. 5 is a block diagram showing the hardware configuration of the interface unit 64. As shown in FIG. 5, the interface unit 64 includes a flash memory 70, a RAM (Random Access Memory) 72, an IF circuit 74, a CPU (Central Processing Unit) 76, and a bus 78. The flash memory 70, the RAM 72, the IF circuit 74, and the CPU 76 are connected to each other by a bus 78.

The flash memory 70 stores a program executed by the CPU 76 and various data necessary for executing the program.

The RAM 72 functions as a work area when the CPU 76 executes a program.

The IF circuit 74 is an interface that controls bidirectional communication with the printer control device 26. The IF circuit 74 acquires image data from the printer control device 26, for example.

The CPU 76 executes the program stored in the flash memory 70 to control the optical scanning unit 16.

FIG. 6 is a functional block diagram showing the configuration of the image processing unit 66. As shown in FIG. 6, the image processing unit 66 includes an attribute separation unit 80, a color conversion unit 81, a black generation unit 83, a gamma correction unit 84, a position correction unit 87, a gradation processing unit 88, and The tag generation unit 86. Part or all of the attribute separation unit 80, the color conversion unit 81, the black generation unit 83, the gamma correction unit 84, the position correction unit 87, the gradation processing unit 88, and the tag generation unit 86 are ASIC (Application Specific Integrated Circuit) or It is realized by a hardware circuit such as FPGA (Field-Programmable Gate Array). The image processing unit 66 may be, for example, a computer having a processor. In this case, in the image processing unit 66, the processor reads the program so that the attribute separation unit 80, the color conversion unit 81, the black generation unit 83, the gamma correction unit 84, the position correction unit 87, the gradation processing unit 88, and the tag generation. It functions as the unit 86.

The attribute separating unit 80 acquires the image data from the interface unit 64. The acquired image data has, for example, an RGB format, a resolution of 1200 dpi, and a bit number of 8 bits. The image data has a plurality of pixel data. Each pixel data has attribute information. The attribute information indicates the type of object that is the source of the pixel. For example, if the pixel is a part of a character, the pixel data has attribute information (for example, text) indicating “character”. If the pixel is a part of a line, the pixel data has attribute information (for example, line) indicating “line”. If the pixel is a part of a figure, the pixel data has attribute information indicating “figure”. If the pixel is a part of a photograph, the pixel data has attribute information indicating “photograph”.

The attribute separation unit 80 separates the attribute information from the image data and outputs it to the tag generation unit 86. The attribute information is, for example, data having the same resolution of 1200 dpi as the acquired image data and a bit number of 2 bits. The attribute separating unit 80 outputs the image data in which the attribute information is separated to the color converting unit 81. The image data output to the color conversion unit 81 is, for example, in the RGB format, has a resolution of 1200 dpi, and has a bit number of 8 bits.

The color conversion unit 81 converts 8-bit RGB format image data into 8-bit CMY format image data. The color conversion unit 81 outputs the image data converted into the CMY format to the black generation unit 83.

The black generation unit 83 generates a black component from the image data converted into the CMY format to generate CMYK format image data. The black generation unit 83 outputs the CMYK format image data to the gamma correction unit 84.

The gamma correction unit 84 corrects the level of each color of the CMYK format image data by linear conversion based on a predetermined correction table or the like. The gamma correction unit 84 outputs the corrected image data to the position correction unit 87.

The tag generation unit 86 generates tag information indicating whether or not each pixel of the 1200 dpi image data forms a character or a line based on the attribute information. For example, the tag generation unit 86 sets the tag information indicating that a character or a line is formed to “1”. The tag generation unit 86 sets the tag information indicating that a character or line such as a background is not formed to “0”. The tag information may be multi-bit. The tag generation unit 86 uses the image data and the attribute information of the image data described above to add the tag information to the pixel data of the target area in order to perform the image processing described later. The tag generation unit 86 adds tag information indicating a character or a line to pixel data of a black pixel having attribute information of the character or the line. The black pixel is a pixel having a pixel value of 1 when the number of gradations is reduced to 1 bit. Light from the light source 50 irradiates the region of the photosensitive drum 34 corresponding to the black pixel. The white pixel is a pixel having a pixel value of 0 when the number of gradations is reduced to 1 bit. The light source 50 does not irradiate the region of the photosensitive drum 34 corresponding to the white pixel. The tag generation unit 86 outputs the generated tag information to the position correction unit 87. The tag generator 86 may output the generated tag information to the gradation processor 88.

The position correction unit 87 corrects noise or image distortion of the image data acquired from the gamma correction unit 84. The position correction unit 87 scales or shifts the image to correct the position of the image. The position correction unit 87 converts the resolution of the image data from 1200 dpi to 2400 dpi. Accordingly, the position correction unit 87 generates 2400 dpi CMYK format image data in which one pixel is represented by a plurality of bits (for example, 8 bits). Further, the position correction unit 87 performs a process of increasing the resolution of the image data from 1200 dpi to 2400 dpi and a process of position correction on the tag information. As a result, the position correction unit 87 assigns tag information to each pixel data whose resolution has been increased. The position correction unit 87 outputs the CMYK format image data and the tag information to the gradation processing unit 88.

The gradation processing unit 88 performs pseudo intermediate processing on the 2400 dpi CMYK format image data by dither processing, error diffusion processing, or the like. As a result, the gradation processing unit 88 generates 1-bit area gradation data from 8-bit image data. For example, the gradation processing unit 88 uses, for example, a binary or multi-valued dither matrix for each CMYK to determine the number of pixels and the pixel values in the area continuously in a halftone cell or line structure. Convert to a different gradation. The gradation processing unit 88 outputs image data including 1-bit area gradation data of 2400 dpi and 1-bit tag information of 2400 dpi to the drive control unit 68 in one pass. For example, the gradation processing unit 88 outputs to the drive control unit 68 2-bit data of 2400 dpi in which the upper bits are CMYK format image data and the lower bits are tag information.

FIG. 7 is a diagram of a schematic configuration of the drive control unit 68. As illustrated in FIG. 7, the drive control unit 68 includes a clock generation unit 90, a light source modulation data generation unit 92 that is an example of an information processing device, and a light source drive unit 94.

The clock generation unit 90 generates a clock signal (or pixel clock signal) indicating the light emission timing of the pixel. For example, the clock generation unit 90 generates a clock signal capable of modulating image data with a resolution corresponding to 4800 dpi. The clock generation unit 90 outputs the clock signal to the light source modulation data generation unit 92.

The light source modulation data generation unit 92 acquires image data and tag information from the image processing unit 66. The light source modulation data generation unit 92 increases the resolution of the acquired image data and tag information. For example, the light source modulation data generation unit 92 generates CMYK format, 4800 dpi and 1-bit image data and tag information based on CMYK format, 2400 dpi and 1-bit image data and tag information. The light source modulation data generation unit 92 modulates the generated image data into a clock signal acquired from the clock generation unit 90 to generate light source modulation data for forming a 4800 dpi image, and outputs it to the light source drive unit 94. To do.

Specifically, the light source modulation data generation unit 92 divides the image data acquired at the resolution of 2400 dpi into the main scanning direction and the sub-scanning direction, and converts it into the image data of 4800 dpi. The light source modulation data generation unit 92 calculates the timing to start writing the image data for each of the image forming stations 18K, 18C, 18M, and 18Y based on the output signal of the synchronization detection sensor. The light source modulation data generation unit 92 superimposes the image dot data of the light emitting units of the light sources 50 of the light source units 46K, 46C, 46M, and 46Y on the clock signal acquired from the clock generation unit 90 in synchronization with the writing start timing. At the same time, based on the information acquired from the image processing unit 66, the light source modulation data independent for each light emitting unit is generated. The light source modulation data generation unit 92 sets an image dot based on matching pattern information for each image section obtained by dividing a pixel when converting the image data to 4800 dpi, and thus the thin line subjected to the thinning process is performed. Generate the image data. The light source modulation data generation unit 92 refers to the tag information and controls the light emission of the light source 50 (for example, power modulation control) to perform the thinning process.

The light source drive unit 94 acquires the light source modulation data corresponding to the image data of 4800 dpi from the light source modulation data generation unit 92. The light source driving unit 94 drives the light sources 50 of the corresponding light source units 46K, 46C, 46M, and 46Y according to the individual light source modulation data for each color output by the light source modulation data generating unit 92. As a result, the light source drive unit 94 causes the light source units 46K, 46C, 46M, and 46Y to emit light with a light amount corresponding to the light source 50.

FIG. 8 is a block diagram illustrating the function of the light source modulation data generation unit 92. As shown in FIG. 8, the light source modulation data generation unit 92 includes a resolution conversion unit 100, a strong exposure data generation unit 102, and a drive current setting unit 104.

The resolution conversion unit 100 includes a buffer memory unit 106, a pattern matching unit 108 that is an example of a second detection unit, an image processing unit 110, a buffer memory unit 112, and a pattern matching unit 114 that is an example of a first detection unit. And a post-processing unit 116.

The buffer memory unit 106 acquires an image matrix including image data and tag information in a region including a target pixel and pixels around the target pixel. The buffer memory unit 106 acquires 2400 dpi and 2-bit data output from the image processing unit 66, and stores the data for a plurality of main scanning lines. The buffer memory unit 106 passes the accumulated 2400 dpi and 2-bit data to the downstream pattern matching unit 108 in response to the reading from the downstream image processing unit 110.

The buffer memory unit 106 stores the 2400-dpi 2-bit data (the upper bits are CMYK format image data and the lower bits are tag information) output by the image processing unit 66. The buffer memory unit 106 passes the accumulated image data and tag information to the pattern matching unit 108 or the image processing unit 110 according to the reading from the image processing unit 110.

The pattern matching unit 108 includes image data (second image data of the second image data) including pixels (hereinafter, “normal pixels”) that are illuminated in normal exposure in the image matrix to pixels that are in an off state (hereinafter, “off pixels” (also referred to as white pixels)). Based on an example) and the arrangement of tag information, it is determined whether or not the target pixel is a pixel forming a line such as a thin line and a character. The normal pixel is an example of the first pixel. Specifically, the pattern matching unit 108 pattern-detects a pixel corresponding to an image processing target of a signal corresponding to an image dot of 2400 dpi and 1 bit by using an image matrix. If there is tag information indicating the attribute of the image data, the pattern matching unit 108 performs pattern matching on the required image area based on the attribute of the image, and detects the boundary of the image. For example, the pattern matching unit 108, based on the image data, has a boundary area (an example of a second boundary area) where the normal pixel is switched to the extinguished pixel, and a boundary area (an example of the second boundary area) where the extinguished pixel is switched to the normal pixel. ) Is detected. Here, the image attribute is, for example, a character, a photograph, a figure, or the like. After that, the pattern matching unit 108 outputs to the image processing unit 110, a signal indicating pattern information indicating whether the pixel is a determination result of a line or a character.

The image processing unit 110 includes an image data generation unit 118, a pixel width setting unit 120, and a light amount information generation unit 122.

The image data generation unit 118 generates thinned image data that has been subjected to thinning processing for thinning the end pixels of the image data by a first pixel width described below. The image data generation unit 118 sequentially selects target pixels from the 2400 dpi image data and converts the image data into high-resolution image data for each target pixel. Specifically, the image data generation unit 118 converts the image data of 2400 dpi into high resolution image data of a pattern defined corresponding to the output of the pattern matching unit 108 by the resolution conversion process. The image data generation unit 118 raises the resolution of the pixels detected by the pattern matching to convert, for example, 2-bit image data of 2400 dpi into 1-bit image data of 4800 dpi, and 1 pixel is 2×. Divide into 2 pixels. The image data generation unit 118 sets the image data subjected to the thinning processing (that is, the thinned image data) by setting the pixel dots based on the pattern information that matches the image sections obtained by dividing the pixels. It is generated and stored in the buffer memory unit 112. That is, the image data generation unit 118 sequentially selects target pixels from the acquired 2400 dpi image data, converts 2400 dpi image data into high-resolution 4800 dpi image data for each target pixel, and performs thinning processing. The thinned image data is generated.

The pixel width setting unit 120 sets the second pixel width at the end of the thinned image data generated by the image data generation unit 118 so that the ratio between the first pixel width and the second pixel width is constant. The first pixel width and the second pixel width will be described later. The first pixel width and the second pixel width may be set in advance.

When the ratio (or ratio) of the light amount of strong exposure (an example of the second light amount) that is stronger than the light amount of the normal exposure to the light amount of the normal exposure (an example of the first light amount) is double, the pixel width setting unit 120 The ratio of the 1-pixel width to the second-pixel width is set to be 1:1. When the ratio of the light amount of the strong exposure (hereinafter, the strong exposure amount) to the light amount of the normal exposure (hereinafter, the normal light amount) is 1.5 times, the pixel width setting unit 120 sets the ratio between the first pixel width and the second pixel width. Is set to be 1:2.

The light amount information generation unit 122 has a normal light amount for exposing pixels that are not included in the second pixel width set by the pixel width setting unit 120 and a strong exposure amount that is larger than the normal light amount for exposing pixels that are included in the second pixel width. The light amount information including and is set. The high exposure dose may have multiple light intensity levels. For example, the light amount information generation unit 122 may set the strong exposure amount to 125%, 150%, 200%, 250%, 300%, etc., which is greater than 100% when the normal light amount is 100%. ..

The light amount information generation unit 122 generates light amount information as power modulation information (or power modulation control pulse signal information) and stores it in the buffer memory unit 112.

For example, the light quantity information generation unit 122 exposes all pixels of the image data before conversion for which the thinning process is performed with the normal light quantity, and all pixels not included in the second pixel width with the normal light quantity. The light amount information is set so that the sum of the integrated value of the light amount and the integrated value of the light amount with which all pixels included in the second pixel width are exposed with the strong exposure amount becomes equal. That is, the light amount information generation unit 122 sets the light amount information so that the integrated value of the light amount becomes equal before and after the conversion by the thinning process, and generates the image data (an example of the first image data).

The light amount information generation unit 122 generates light amount information in which the ratio of the strong exposure amount to the normal light amount is 1 to 3 times. The light amount information generation unit 122 preferably generates the light amount information in which the ratio of the strong exposure amount to the normal light amount is in the range of 1.5 times to 2 times. The light amount information generation unit 122 may individually set the normal light amount and the strong exposure amount (hereinafter, the first setting), or may set the normal light amount and the strong exposure amount with a ratio based on one of the normal light amount and the strong exposure amount. Alternatively, the normal light amount and the strong exposure amount may be set by selecting the first setting and the second setting.

The buffer memory unit 112 generates the thinned image data generated by the image data generation unit 118 performing the thinning process for thinning the end pixels of the image indicated by the image data by the first pixel width, and the light amount information generation unit 122. The obtained power modulation information (power modulation control pulse signal information) is acquired from the image processing unit 110 and stored.

The pattern matching unit 114 acquires the image matrix of the thinned image data and the power modulation information, which is the information of the target pixel and the surrounding pixels in the main scanning direction. The pattern matching unit 114 determines whether or not the target pixel is a conversion target pixel based on the arrangement of the thinned image data and the power modulation information in the image matrix. Specifically, the pattern matching unit 114 performs pixel matching on the basis of the image data (thin line image data or power modulation information) generated by the image processing unit 110, and thereby pixels that are irradiated with strong exposure (hereinafter, strongly exposed pixels). A boundary area (an example of a first boundary area) that is an area including a normal pixel that is in contact with a boundary between the normal pixel and The strongly exposed pixel is an example of the second pixel. The boundary area, which is an area including a normal pixel that is in contact with the boundary between the strong-exposure pixel and the normal pixel, is a boundary area that is an area that includes a normal pixel in contact with the boundary that switches from the strong-exposure pixel to the normal pixel, and the normal pixel to the strong-exposure. It includes a boundary area that is an area including normal pixels that are in contact with a boundary that switches to a pixel. The pattern matching unit 114 outputs a signal indicating pattern information based on the determination result to the post-processing unit 116 together with the thinned image data and the power modulation information.

The post-processing unit 116 converts the thinned image data and the power modulation information based on the pattern information acquired from the pattern matching unit 114. Specifically, the post-processing unit 116 converts the normal pixel in the boundary area detected by the pattern matching unit 114 into a light-off pixel, and arranges the light-off pixel between the strong-exposure pixel and the normal pixel. For example, the post-processing unit 116 sets a part of the normal pixels in the boundary area to a strongly exposed pixel in the setting of the light-off pixel in the boundary area, and sets the remaining normal pixels as the unlit pixels. The post-processing unit 116 converts a part of the normal pixels in the boundary area into strong-exposure pixels so that the integrated values of the light amounts before and after the setting of the light-off pixels in the boundary area become equal, and turns off the remaining normal pixels. It is preferable to set to pixels. The post-processing unit 116 outputs the converted thinned image data and power modulation information to the strong exposure data generation unit 102. The post-processing unit 116 may set the normal light amount and the strong exposure amount when setting the normal pixel and the strong exposure pixel. In this case, the post-processing unit 116 may individually set the normal light amount and the strong exposure amount (first setting), or may set the normal light amount and the strong exposure amount based on one of the ratios. Alternatively, the normal light amount and the strong exposure amount may be set by selecting (second setting) or the first setting and the second setting.

The strong exposure data generation unit 102 controls the light source modulation signal (for example, a light source modulation pulse signal) that controls the light emission of the light source 50 of the light source unit 46 according to the thinned image data, and the power modulation generated by the light amount information generation unit 122. A power modulation control pulse signal (for example, a drive current switching signal) is generated based on the information.

The strong exposure data generation unit 102 has a pulse generation unit 123. The pulse generator 123 outputs a light source modulation pulse signal and a power modulation control pulse signal, which are obtained by serially converting the thinned image data and the power modulation information based on a high frequency clock. The strong exposure data generation unit 102 outputs a light source modulation pulse signal including a strong exposure signal, an undershoot ON signal, a bias signal, an overshoot ON signal, and a lighting control signal to the light source drive unit 94. The strong exposure data generation unit 102 outputs to the drive current setting unit 104 a power modulation control pulse signal that functions as a switching signal for switching the selector 130 described later.

The drive current setting unit 104 switches the light source applied current data (for example, drive current data) applied to the light source 50 of the light source unit 46 in association with the normal light amount and the strong exposure amount based on the power modulation control pulse signal. Output. The drive current setting unit 104 performs light source applied current modulation (for example, power modulation) that changes the exposure intensity for thin lines and characters. The drive current setting unit 104 includes a power modulation value holding unit 124, a power modulation current setting unit 126, a normal current setting unit 128, and a selector 130.

The power modulation value holding unit 124 holds data of a magnification (for example, a power modulation value) for changing the normal light amount to obtain a strong exposure amount.

The power modulation current setting unit 126 scales the normal light amount with reference to the magnification held by the power modulation value holding unit 124, and sets the strong exposure amount. The power modulation current setting unit 126 sets the strong exposure amount so that the integrated value of the normal light amount and the strong exposure amount becomes equal before and after the first image processing described later or before and after the second image processing described later. May be. The power modulation current setting unit 126 sets the second light source applied current data, which is the data of the current applied to the light source 50 to output the strong exposure amount, and outputs it to the selector 130.

The normal current setting unit 128 sets the first light source applied current data, which is the data of the current applied to the light source 50 to output the normal light amount, and outputs it to the selector 130.

The selector 130, based on the power modulation control pulse signal acquired from the strong exposure data generation unit 102, the first light source applied current data for outputting the normal light amount, and the second light source application for outputting the strong exposure amount. One of the current data is selected and output to the light source drive unit 94.

FIG. 9 is a block diagram illustrating the function of the light source driving unit 94. As shown in FIG. 9, the light source drive unit 94 includes a DAC (Digital To Analog Converter) 132 and switches 134, 136, 138, 140, 142. In the example shown in FIG. 9, the light source 50 is described as a single laser diode, but it is not limited to this. For example, the light source 50 may be an LDA (Laser Diode Array) or a VCSEL (Vertical Cavity Surface Emitting LASER).

In the example shown in FIG. 9, the light source drive unit 94 switches on and off the connection with the current source 98 that supplies a forward current to the light source 50 based on the light source applied current data and the light source modulation pulse signal, The amount of current flowing through the light source 50 is controlled.

The DAC 132 digitally sets the current applied to the light source 50 by a DAC (Digital To Analog Converter) code based on the light source applied current data output by the light source modulation data generation unit 92.

The switch 134 controls ON/OFF of the connection with the current source 98 based on the lighting control signal included in the light source modulation pulse signal output from the light source modulation data generation unit 92, so that the light source 50 has a desired lighting pattern. A switching current Isw is supplied to control the emission and extinction of the light source 50. The lighting control signal determines the time width of the switching current Isw flowing through the light source 50 in the normal exposure state.

The switch 136 supplies the overshoot current Iov by controlling ON/OFF of the connection with the current source 98 based on the overshoot ON signal included in the light source modulation pulse signal output from the light source modulation data generation unit 92. And the stop are switched to control the amount of current flowing through the light source 50. The overshoot ON signal determines the time width of the overshoot current Iov flowing through the light source 50 when the current rises in order to switch to the light emitting state.

The switch 138 controls ON/OFF of the connection with the current source 98 based on the bias signal included in the light source modulation pulse signal output from the light source modulation data generation unit 92, thereby supplying and stopping the bias current Ib. Is switched to control the amount of current flowing through the light source 50. The bias signal determines the time width of the bias current Ib flowing through the light source 50 in the off state.

The switch 140 supplies the undershoot current Iud by controlling the on/off of the connection with the current source 98 based on the undershoot ON signal included in the light source modulation pulse signal output from the light source modulation data generation unit 92. And the stop are switched to control the amount of current flowing through the light source 50. The undershoot ON signal determines the time width of the undershoot current Iud flowing through the light source 50 at the fall of the current in order to switch it to the off state.

The switch 142 supplies the strong exposure current Ist by controlling the on/off of the connection with the current source 98 based on the strong exposure signal included in the light source modulation pulse signal output from the light source modulation data generation unit 92. The amount of current flowing through the light source 50 is controlled by switching between stop and stop. The strong exposure signal determines the time width of the strong exposure current Ist flowing through the light source 50 in the strong exposure state.

As a result, the light source driving unit 94 causes the light source 50 to irradiate the light source 50 with a normal amount of light, and the bias current Ib supplied to the light source 50 for irradiating light for forming a latent image on the photosensitive drum 34 according to the image to be formed. Switching current Isw supplied for that purpose, strong exposure current Ist supplied for irradiating the light source 50 with a strong exposure amount of light, overshoot current Iov supplied for the rising of the current, and undershoot current Iud supplied for the falling of the current. Using, the light amount of the light emitted from the light source 50 is switched to the normal light amount, the strong exposure amount, and the extinction according to the image data converted by the post-processing unit 116, and the light source 50 is driven. Further, the light source drive unit 94 corrects the overshoot current Iov and the undershoot current Iud. For example, the light source drive unit 94 corrects the overshoot current Iov with reference to the current before rising, and corrects the undershoot current Iud with reference to the current before falling. Here, the light source driving unit 94 may correct the overshoot current Iov and the undershoot current Iud when the normal light amount and the strong exposure amount are changed by the light amount information generating unit 122 or the post-processing unit 116.

FIG. 10 is a diagram showing the relationship between the drive current flowing through the light source 50 and the control signal. In FIG. 10, the horizontal axis represents time. In the upper diagram of FIG. 10, the vertical axis represents the magnitude of current. In the lower diagram of FIG. 10, the vertical axis represents the magnitude of the signal (for example, corresponding to assert and negate). The light source drive unit 94 supplies each current to the light source 50 based on the bias signal, the overshoot ON signal, the undershoot ON signal, the lighting control signal, and the strong exposure signal.

The bias current Ib is a drive current that improves the rise of light emission of the light source 50 without affecting development. The bias current Ib flows through the light source 50 while the bias signal is in the asserted state, for example.

The switching current Isw is a drive current that is added to the bias current Ib to irradiate the light source 50 with the normal light amount required for development. The switching current Isw flows through the light source 50 while the lighting control signal is in the asserted state, for example.

The overshoot current Iov is a drive current that improves dullness of the drive current due to parasitic capacitance and the like (for example, dull rise of the switching current Isw). The overshoot current Iov flows to the light source 50 while the overshoot ON signal is in the asserted state, for example.

The undershoot current Iud is a driving current that improves dullness of the driving current due to parasitic capacitance and the like (for example, dullness of the falling edge of the switching current Isw). The undershoot current Iud flows through the switch 140 while the undershoot ON signal is in the asserted state, for example.

The strong exposure current Ist is a drive current that is added to the bias current Ib and the switching current Isw to irradiate the light source 50 required for development with a strong exposure amount of light. The strong exposure current Ist flows to the light source 50 while the strong exposure signal is in the asserted state, for example.

The bias current Ib, the switching current Isw, the overshoot current Iov, the undershoot current Iud, and the strong exposure current Ist should be corrected by process control control in order to optimize the current amount under developing conditions such as temperature. Is preferred.

FIG. 11 is a diagram illustrating the first image processing. In FIG. 11, the vertical direction indicates the sub scanning direction, and the horizontal direction indicates the main scanning direction. The model shown in FIG. 11 is a pixel row (see N line) extracted in a region in which the pixel width in the main scanning direction is 9 pixels and the pixel width in the sub scanning direction is 1 pixel. The first image processing is executed by the buffer memory unit 106, the pattern matching unit 108, and the image processing unit 110.

The upper bits of the data stored in the buffer memory unit 106 before the conversion of the first image processing by the image processing unit 110 are the image data, and the lower bits are the tag information. The upper bits of the data converted by the first image processing are the image data, and the lower bits are the power modulation control pulse signal. The number to the left of each pixel in parentheses is the pixel bit. The pixel bit “0” indicates a white pixel, and the pixel bit “1” indicates a black pixel. The numerical value on the right side in parentheses of each pixel before conversion is a tag bit. The tag bit “1” indicates a character or a line. The numerical value on the right side in parentheses of each pixel after conversion is the power modulation control pulse signal bit. "1" of the power modulation control pulse signal bit indicates strong exposure, and "0" indicates normal exposure. The resolution before conversion is 2400 dpi. The resolution after conversion is 4800 dpi.

The normal light amount is a light amount when the strong exposure process is off (for example, the strong exposure current Ist does not flow). When the normal light amount is 100%, the strong exposure amount is higher than 100%, for example, 125%, 150%, 200%, 250%, or 300%.

The first image processing, which is thinning processing, will be described. As shown in FIG. 11, in the thinning process, the pattern matching unit 108 determines in advance the pixels that are the ends of the characters or lines from the data stored in the buffer memory unit 106. In the image data stored in the buffer memory unit 106, the pattern matching unit 108 is provided at both ends of a region of normal pixels including normal pixels (for example, two normal pixels) that are in contact with a boundary between a non-lighted pixel and a normal pixel. Certain boundary areas Ara1 and Ara2 are detected. The image data generation unit 118 of the image processing unit 110 narrows the boundary regions Ara1 and Ara2 at the ends of the image (for example, the black pixel region) indicated by the image data by the first pixel width, that is, the boundary regions at the ends. The normal pixels on the unlit pixel side of Ara1 and Ara2 are changed to unlit pixels (for example, white pixels) by the first pixel width. The first pixel width may be a preset arbitrary value.

In the example shown in FIG. 11, in the 7 pixels (see N line) in the main scanning direction in which the value of the pixel before conversion is (1,1), the image data generation unit 118 of the image processing unit 110 causes (For example, thinning processing is performed to change the first pixel width (for example, one pixel width before conversion) of the boundary areas Ara1 and Ara2 that switch from the extinguished pixel to the tagged state from the normal light amount to the extinguished state. The pixel width setting unit 120 of the image processing unit 110 makes the ratio of the first pixel width to the second pixel width of the second pixel width at the end of the thinned image data generated by the image data generation unit 118 constant. To set. The light amount information generation unit 122 of the image processing unit 110 determines the light amount of the second pixel width (for example, one pixel before conversion) of the boundary regions Ara1 and Ara2 of the thinned image data newly generated by the thinning process. , Change to a strong exposure amount with a larger light amount than the normal light amount. The first pixel width shown in FIG. 11 is the same as the second pixel width, but is not limited to this. The image processing unit 110 also converts the N lines into N lines and N+1 lines by increasing the resolution.

FIG. 12 is a diagram showing conversion of the light amount in the first image processing of FIG. As shown in FIG. 12, the normal light amount is applied to seven pixels of the N line in which the pixel value is (1,1) before conversion by the first image processing. After the conversion by the first image processing, the strong exposure amount is applied to the strong exposure regions of N line and N+1 line indicated by the second pixel width, and the normal light amount is between the strong exposure region and the strong exposure region. Is irradiated to the area. Further, the area of the first pixel width at the end of the area of the normal pixel before conversion is turned off.

FIG. 13 is a diagram illustrating the second image processing after the first image processing. In FIG. 13, the vertical direction indicates the sub scanning direction, and the horizontal direction indicates the main scanning direction. The model shown in FIG. 13 is a pixel row (see n line) extracted in a region in which the pixel width in the main scanning direction is 18 pixels and the pixel width in the sub scanning direction is 1 pixel. The pixel width here is the pixel width after the first image processing and is twice the pixel width before the first image processing. The second image processing is executed by the buffer memory unit 112, the pattern matching unit 114, and the post-processing unit 116.

In the example shown in FIG. 13, among the pixels having the pixel values of (1, 1), the pixels with fine dot hatching are the strongly exposed pixels (see the fifth, sixth, etc. from the left of the n line in the above figure). Among the pixels having the pixel value of (1, 1), the pixels with coarse dot hatching are the normal pixels (see the 7th to 12th from the left of the n line in the above figure). Pixels having a pixel value of (0,0) are extinguished pixels (see the first to fourth positions from the left on the n line in the above figure).

In the second image processing, the pattern matching unit 114 performs pattern matching only in the main scanning direction. The pattern matching unit 114 outputs the data output by the image processing unit 110 and stored in the buffer memory unit 112 (the upper bits after the conversion of the first image processing are the image data, and the lower bits are the power modulation control pulse signal). Pattern matching). The pattern matching unit 114 causes one end of the area of the normal pixel including the normal pixel that is in contact with the boundary where the strongly-exposed pixel is switched to the normal pixel by the pattern matching (for example, the 7th and 8th positions from the left of the n line in the above figure are shown. A boundary area Arb1 including two normal pixels, and the other end of the area of the normal pixel including the normal pixel in contact with the boundary where the normal pixel is switched to the strongly exposed pixel (for example, from the right of the n line in the above figure, 7, A boundary area Arb2) including the second normal pixel for two pixels is detected.

In the second image processing, the post-processing unit 116, as shown in the converted n line in the lower diagram of FIG. 13, in the normal exposure area, changes from the normal exposure detected by the pattern matching unit 114 to the strong exposure. In the boundary area Arb1, the normal pixel on the strong exposure side is converted into the strong exposure pixel, and the normal pixel on the center side of the normal exposure area is converted into the extinguished pixel. In the normal exposure region, the post-processing unit 116 converts the normal pixel on the strong exposure side into the strong exposure pixel in the boundary region Arb2 at the end portion where the normal exposure detected by the pattern matching unit 114 is switched to the strong exposure, and The normal pixel on the center side of the exposure area is converted to a non-lighted pixel.

FIG. 14 is a diagram showing conversion of the light amount in the second image processing of FIG. As shown in FIG. 14, as shown in a boundary region Arb1 including two normal pixels at one end of the normal pixel region, the strong exposure is switched to the extinguished state, and then the extinguished state is switched to the normal exposure. Further, as shown in a boundary area Arb2 including two normal pixels at the other end of the normal pixel area, the normal exposure is switched to the extinguished state, and then the extinguished state is switched to the strong exposure. As a result, the post-processing unit 116 inserts an extinguished pixel between the strong-exposure pixel and the normal pixel, and the strong-exposure that is easily affected by the deviation from the ideal value due to the correction of the overshoot current and the undershoot current. The area where the normal exposure is switched to the normal exposure and the area where the normal exposure is switched to the strong exposure are reduced. In other words, the post-processing unit 116 reduces the area where the unstable switching current is switched to the overshoot current and the undershoot current, and the area where the overshoot current and the undershoot current are switched to the switching current.

FIG. 15 shows a flowchart of the light amount adjustment processing. As shown in FIG. 15, in the light amount adjustment process, the light source drive unit 94 adjusts the normal light amount based on the light source modulation pulse signal including the bias signal and the lighting control signal (S102). The light source drive unit 94 adjusts the strong exposure amount based on the light source modulation pulse signal including the strong exposure signal, the bias signal, and the lighting control signal (S104). The light source drive unit 94 adjusts the overshoot current based on the light source modulation pulse signal including the overshoot ON signal (S106). The light source drive unit 94 adjusts the undershoot current based on the light source modulation pulse signal including the undershoot ON signal (S108). After that, the light source drive unit 94 repeats the light amount adjustment processing.

FIG. 16 is a diagram for explaining the timing of light amount adjustment. The horizontal axis shown in FIG. 16 represents time, and the vertical axis represents signal magnitude (Upper is Low, Lower is High). The FGATE_Ye_N signal is a yellow print area of the image of one page in the sub-scanning direction. The FGATE_Ma_N signal, the FGATE_Cy_N signal, and the FGATE_K_N signal are magenta, cyan, and black print areas in the sub-scanning direction of the image of one page, respectively. The light source drive unit 94 executes light amount adjustment processing (for example, light amount correction) for each color outside the color printing area in the tandem color machine, which is the Low period of each FGATE_N signal shown in FIG. The light source drive unit 94 may correct the overshoot current Iov and the undershoot current Iud between the recording papers on which an image is printed. As a result, the information processing device 63 can suppress the reduction in printing speed.

FIG. 17 is a flowchart of the pixel setting process performed by the drive control unit 68 of the information processing device 63. The pixel setting process is an example of a pixel setting method. As shown in FIG. 17, in the pixel setting process, the pattern matching unit 108 of the drive control unit 68 detects the boundary area between the normal pixel and the unlit pixel of the image based on the image data stored in the buffer memory unit 106. Yes (S202). The image processing unit 110 changes a part of the normal pixels in the boundary area into strongly exposed pixels, and changes the rest into extinguished pixels (S204). The pattern matching unit 114 detects the boundary area between the normal pixel and the strongly exposed pixel of the image based on the image data stored in the buffer memory unit 112 (S206). The post-processing unit 116 changes some of the normal pixels in the boundary area to strongly exposed pixels, and changes the rest to extinguished pixels (S208).

As described above, the information processing device 63 of the image forming apparatus 10 sets the extinguished pixel between the normal exposure and the strong exposure, so that the overshoot current and the undershoot current can be set based on the bias current. .. As a result, the information processing device 63 can accurately correct the overshoot current and the undershoot current.

In the information processing device 63, in the first image processing, the image processing unit 110 converts the normal pixels into the extinguished pixels and the strongly exposed pixels so that the integrated values of the light amounts before and after the conversion become equal. The image quality can be improved while suppressing an increase in power consumption.

In the information processing device 63, in the second image processing, the post-processing unit 116 converts the normal pixel into the extinguished pixel and the strongly exposed pixel so that the integrated value of the light amount becomes equal before and after the conversion. The image quality can be improved while suppressing an increase in power consumption.

In the information processing device 63, the post-processing unit 116 selects the first setting, the second setting, or the first setting and the second setting to set the normal light amount and the strong exposure amount. The degree of freedom in setting the normal light amount and the strong exposure amount can be improved.

In the information processing device 63, the pattern matching unit 108 detects the boundary area between the normal pixel and the extinguished pixel by pattern matching, so that the boundary area can be detected more accurately.

Since the information processing device 63 corrects the overshoot current Iov and the undershoot current Iud when the normal light amount and the strong exposure amount are changed, it is possible to more appropriately irradiate the normal light amount and the strong exposure amount.

The function, connection relationship, number, arrangement, etc. of each configuration of the above-described embodiments may be changed as appropriate.

For example, the information processing device 63 of the embodiment may be a computer. In this case, part or all of the interface unit 64, the image processing unit 66, and the drive control unit 68 may be realized as a function of the information processing device 63 that has read the program for pixel setting processing. The program for pixel setting processing executed by the information processing device 63 includes the above-described units (the interface unit 64, the image processing unit 66, and a part of the drive control unit 68, for example, the resolution conversion unit 100 of the drive control unit 68). A module configuration including a buffer memory unit 106, a pattern matching unit 108, an image processing unit 110, a buffer memory unit 112, a pattern matching unit 114, a post-processing unit 116, a strong exposure data generation unit 102, and a light source driving unit 94). ing. The actual hardware of the information processing device 63 may be the same as that shown in FIG. 5, and the CPU reads out and executes the program for pixel setting processing from a storage unit such as a ROM, so that the above units are stored in the main storage device. Loaded. As a result, the above-mentioned units are generated in the main storage device, and these functions are realized by the computer.

For example, the program for the pixel setting process executed by the information processing device 63 of the present embodiment is provided by being pre-installed in the ROM or the like. The program for pixel setting processing executed by the information processing apparatus 63 of the present embodiment is a file in an installable format or an executable format, and is a CD-ROM, a flexible disk (FD), a CD-R, a DVD (Digital Versatile). It may be configured to be recorded and provided in a computer-readable recording medium such as a disk).

Furthermore, the program for pixel setting processing executed by the information processing apparatus 63 of the present embodiment is stored in a computer connected to a network such as the Internet and is configured to be provided by being downloaded via the network. Is also good. Further, the program for pixel setting processing executed by the information processing apparatus 63 of the present embodiment may be provided or distributed via a network such as the Internet.

The above embodiments are presented as examples and are not intended to limit the scope of the present invention. The novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. The embodiments and modifications of the embodiments are included in the scope and the gist of the invention, and are also included in the invention described in the claims and the scope equivalent thereto.

10... Image forming device 16... Optical scanning unit 18, 18C, 18K, 18M, 18Y... Image forming station 46, 46C, 46K, 46M, 46Y... Light source unit 50... Light source 63... Information processing device 64... Interface unit 66... Image Processing unit 68... Drive control unit 94... Light source drive unit 100... Resolution conversion unit 102... Strong exposure data generation unit 104... Drive current setting unit 108... Pattern matching unit 110... Image processing unit 114... Pattern matching unit 116... Post-processing unit 118... Image data generation unit 120... Pixel width setting unit 122... Light amount information generation units Ara1, Ara2, Arb1, Arb2... Border region Ib... Bias current Iov... Overshoot current Ist... Strong exposure current Isw... Switching current Iud... Undershoot Electric current

Japanese Patent No. 4984525 JP, 2005-232698, A

Claims (10)

A first pixel, which is a pixel to which a first light amount is emitted based on the first image data from a light source that emits light for forming a latent image according to an image to be formed, and a second light amount which is stronger than the first light amount. A first detection unit that detects a first boundary region that is a region including the first pixel that is in contact with a boundary with a second pixel that is a pixel emitted from the light source,
A post-processing unit that converts the first pixel of the first boundary region into an extinguished pixel that is a pixel for extinguishing the light source, and arranges the extinguished pixel between the first pixel and the second pixel; ,
The light source irradiates according to the first image data converted by the post-processing unit by using an overshoot current supplied at the rising edge of the current supplied to the light source and an undershoot current supplied at the falling edge of the current. A light source drive unit that drives the light source by switching the light amount of the light to the first light amount, the second light amount, and the light extinction;
An information processing apparatus including. A second detection unit that detects a second boundary region that is a region that includes the first pixel and that is in contact with a boundary between the first pixel and the extinguished pixel in the second image data that includes the first pixel and the extinguished pixel;
An image processing unit that generates the first image data obtained by converting a part of the first pixel in the second boundary region into the extinguished pixel and the second pixel so that the integrated values of the light amounts before and after the conversion become equal. When,
Further equipped with,
The information processing apparatus according to claim 1, wherein the first detection unit detects the first boundary region based on the first image data. In the setting of the extinguished pixels in the first boundary area, the post-processing unit converts a part of the first pixels in the first boundary area into the second pixels and sets the rest into the extinguished pixels. The information processing apparatus according to claim 1. The post-processing unit converts a part of the first pixels in the first boundary area into the second pixels so that integrated values of light amounts before and after the setting of the extinguished pixels in the first boundary area become equal to each other. The information processing apparatus according to claim 3, wherein the rest is set to the extinguished pixels. The post-processing unit,
A first setting for individually setting the first light amount and the second light amount, or
A second setting that is set at a ratio based on one of the first light amount and the second light amount, or
The information processing apparatus according to claim 1, wherein either the first setting or the second setting is selected to set the first light amount and the second light amount. The information processing apparatus according to claim 1, wherein the first detection unit detects the first boundary area by pattern matching. The information processing device according to claim 1, wherein the light source driving unit corrects the overshoot current and the undershoot current when the first light amount and the second light amount are changed. The information processing device according to claim 1, wherein the light source drive unit corrects the overshoot current and the undershoot current between the paper on which the image is printed. A first pixel, which is a pixel to which a first light amount is emitted based on the first image data from a light source that emits light for forming a latent image according to an image to be formed, and a second light amount which is stronger than the first light amount. A first detection step of detecting a first boundary area that is an area including the first pixel that is in contact with a boundary with a second pixel that is a pixel emitted from the light source,
A post-processing step of converting the first pixel of the first boundary region into an extinguished pixel that is a pixel for extinguishing the light source, and arranging the extinguished pixel between the first pixel and the second pixel; ,
The light source irradiates according to the first image data converted in the post-processing step by using an overshoot current supplied at a rising edge of a current supplied to the light source and an undershoot current supplied at a falling edge of the current. A light source driving step of driving the light source by switching the light amount of the light to the first light amount, the second light amount, and the light extinction;
And a pixel setting method. In the computer provided in the image forming apparatus,
A first pixel, which is a pixel to which a first light amount is emitted based on the first image data from a light source that emits light for forming a latent image according to an image to be formed, and a second light amount which is stronger than the first light amount. A first detection function of detecting a first boundary area that is an area including the first pixel that is in contact with a boundary with a second pixel that is a pixel emitted from the light source,
A post-processing function of converting the first pixel of the first boundary region into an extinguished pixel which is a pixel in which the light source is extinguished, and arranging the extinguished pixel between the first pixel and the second pixel; ,
The light source emits light according to the first image data converted by the post-processing function, using an overshoot current supplied at the rising edge of the current supplied to the light source and an undershoot current supplied at the falling edge of the current. A light source driving function of driving the light source by switching the light amount of the light to the first light amount, the second light amount, and the light extinction;
A program that realizes.

Images