JP4487520B2 - Image forming apparatus and method - Google Patents

Description

  The present invention relates to an image forming apparatus and method, and more particularly to an image forming apparatus and method for efficiently using a memory area of a memory device in which image data is written and read in an image forming apparatus used in a color copying machine or the like. It is about.

  Conventionally, a recording apparatus that forms a latent electrostatic image by projecting a laser beam modulated in accordance with an input image signal onto a photosensitive drum as a photosensitive member, and develops the latent image with toner is used for yellow (Y) and magenta (M ), Cyan (C), and black (K) for each color, and according to the conveyance of the recording paper on the transfer belt, each color image is superimposed and transferred from the recording device corresponding to each color to obtain a color image. An image forming apparatus having a tandem configuration is known.

  In this type of apparatus, misalignment due to misalignment of image writing timing in the main scanning direction and sub-scanning direction in each color image due to a mechanical attachment error between the photosensitive drums of each color or a difference in optical path length of the laser beam corresponding to each color. In addition, since a change in magnification and a change in inclination occur in each color image, it is necessary to perform registration correction for each color image. That is, as shown in FIG. 10, in an image forming apparatus having a tandem configuration when registration correction is not performed, when the acquired image data 10 is transferred to the recording paper 11 without correction, the output image 12 is shifted. Will occur. Therefore, as shown in FIG. 11, by performing registration correction on the acquired image data 14, an image 16 having no deviation similar to the original image is transferred to the recording paper 11.

  As a specific method for performing this registration correction, for example, the following has been proposed. That is, prior to the copy operation of the original image, predetermined color pattern images are formed at two positions perpendicular to the transport direction on the transfer belt, and the pattern images are read by a sensor such as a CCD in the order of transport of each color, and stored in the memory. The image is taken into the apparatus to remove noise components on the transfer belt, and in order to calculate the center position of each color pattern image, a predetermined calculation is performed in the main scanning direction and the sub-scanning direction. The CPU controls the image writing timing, and the reflection mirror in the laser beam optical path is driven and controlled by the optical path correction mechanism (actuator) in the optical path direction and the rotation direction with respect to the optical path to perform magnification correction and inclination correction of each color image. (For example, see Patent Document 1 below).

JP-A-1-142672

  However, the conventional image forming apparatus has a problem that a large-scale memory device must be installed because the amount of image data to be written in the memory device increases when the correction amount for registration correction is large. Was.

  FIG. 12 is a diagram showing a state of the memory device 24 in which image data is written in the conventional image forming apparatus. For the sake of easy explanation, magenta (M) and cyan (C) are generated only in the sub-scanning direction. The case of correcting the deviation is illustrated. In FIG. 12, after capturing the input image 20, a predetermined image calculation 21 is performed, and the image data after deviation correction subjected to registration correction is shown as magenta (M) image data 22 M and cyan (C) image data 22 C. Yes.

  Here, the magenta (M) image data 22M in FIG. 12 indicates that the registration correction amount increases toward the left side of the page. In such a case, since the magenta (M) image data 22M and the cyan (C) image data 22C are written on the memory device 24, the image data on the left side of the paper with a large registration correction amount is stored in the memory device 24. Use capacity increases. On the other hand, the image data on the right side of the page requires less memory capacity than the left side image data. Therefore, when the writing range of the image data occupying the memory device 24 is schematically shown, the use area of the memory device 24 can be shown as a trapezoidal shape 26 in which the lower right side of the memory device 24 is cut off.

  As described above, the conventional image forming apparatus cannot efficiently use the memory device 24. Further, as described above, the correction amount for registration correction is caused by a mechanical error factor of the image forming apparatus. However, a maximum value of this correction amount is obtained in advance, and the correction amount corresponds to this maximum correction amount. Memory capacity had to be secured (for example, the range of reference numeral 28 in FIG. 12). Therefore, since the conventional image forming apparatus requires a large-scale memory corresponding to the correction amount, it has been extremely difficult to realize the image forming apparatus at a low cost.

  The present invention has been made in view of the above problems, and an object of the present invention is to efficiently use a memory area so that an image having an image quality equal to or higher than that of a conventional memory device can be obtained even with a small capacity memory device. It is to realize a forming apparatus.

An image forming apparatus according to the present invention acquires a two-dimensional address indicating a position in a main scanning direction and a sub-scanning direction of image data, and writes the image data in the memory device. Means for acquiring the two-dimensional address, specifying a reading range in the main scanning direction and the sub-scanning direction, and reading the image data from the memory device; and the two-dimensional acquired by the writing means or the reading means A control unit that converts an address into an address and controls writing or reading of image data to or from the memory device, wherein the control unit stores image data so as to fill a free area of the memory device. By performing write control, the address conversion of a two-dimensional address corresponding to the usage status of the memory device is performed.

  In other words, the usage status of the memory device in the present invention refers to the usage status of the memory area, and the memory area is efficiently used so that a free area does not occur in the memory area as much as possible. Even in the case of an apparatus, it is possible to obtain an image quality equivalent to or higher than that of the prior art.

  In the image forming apparatus according to the present invention, the image data includes a color misregistration correction amount based on relative misregistration correction information between colors in color image formation, and color misregistration correction is performed by the address conversion performed by the control unit. Image data writing control is performed so as to fill a free space of the memory device depending on the amount.

  That is, the image data targeted by the present invention includes those for which color registration correction is performed. The image data subjected to color registration correction includes a difference in the amount of image data depending on the amount of correction, and writing to the memory device as it is in the prior art results in useless free space in the memory device. End up. The present invention is characterized in that image data writing correction is performed so as not to generate this useless empty area.

Furthermore, as one aspect of the image forming apparatus according to the present invention, the memory device is configured as an aggregate of a plurality of memory ICs, and each of the memory ICs has an address corresponding to a position in the main scanning direction. In addition, the image data is divided into at least two write areas, and the image data is further divided into the number of areas corresponding to the number of divided write areas of the memory IC in the main scanning direction . Then, the control unit performs the write control so that the write start positions of the divided image data in the memory devices are different from each other, and one write area is filled. Thus, when image data that cannot be written is generated, control is performed so that the image data that cannot be written is written in an empty area of another writing area.

  Such an embodiment can be applied to an image forming apparatus having a laser scanner type optical scanning system using a semiconductor laser or a high resolution image forming apparatus using a surface emitting semiconductor laser VCSEL. By applying this aspect, it is possible to increase the efficiency of reading from the memory device, and high-speed processing is possible even with a high-resolution image forming apparatus.

  As another aspect of the image forming apparatus according to the present invention, the memory device is configured as an aggregate of a plurality of memory ICs, and the control unit sequentially instructs the image data to be written on the same memory IC. It is preferred not to.

  Such an embodiment is applicable to an image forming apparatus having an LED array type optical scanning system. The LED array type optical scanning system is configured by integrating about 8 to 16 infrared LEDs (light emitting diodes) per millimeter and arranging them in a linear array. By the way, in the memory device, there is a restriction that data cannot be read simultaneously when data of different addresses is written in the same memory IC. Therefore, in the memory device when the LED array type optical scanning system is used. Efficient image data reading becomes a problem. Therefore, in this aspect, the memory ICs are arranged in the vertical direction with respect to the image data writing direction, the image data is sequentially written to different memory ICs, and the image data is not continuously written to the same memory IC. With such a configuration, it is possible to efficiently read image data from the memory device.

  The image forming method according to the present invention stores acquired image data in a memory device, and when obtaining desired image data output by performing predetermined correction, the image data is efficiently stored in the memory device by a computer. A writing unit for writing image data to the memory device, obtaining a two-dimensional address indicating a position of the image data in the main scanning direction and the sub-scanning direction; and an image for the memory device. A step in which a control unit that performs data writing control converts the two-dimensional address acquired by the writing unit in accordance with a use state of the memory device, and performs image data writing control so as to fill an empty area of the memory device; And a control unit that performs read control of the image data to the memory device reads the image data from the memory device. A step of address-converting the acquired two-dimensional address of the reading means, and a step of the reading means acquiring the address-converted two-dimensional address and specifying a reading range in the main scanning direction and the sub-scanning direction; It is characterized by having.

  In the image forming method according to the present invention, the image data includes a color misregistration correction amount based on relative color misregistration correction information in color image formation, and the control unit performs a writing control step of the image data. In this case, the address conversion includes a step of performing writing control of image data so as to fill an empty area of the memory device caused by the color misregistration correction amount.

Furthermore, as one aspect of the image forming method according to the present invention, the memory device is configured as an aggregate of a plurality of memory ICs, and each of the memory ICs has an address corresponding to a position in the main scanning direction. In addition, the image data is divided into at least two write areas, and the image data is further divided into the number of areas corresponding to the number of divided write areas of the memory IC in the main scanning direction . In the step of performing the writing control, the control unit that performs the writing control performs the writing control so that the writing start positions of the divided image data in the memory devices are different from each other. In addition, when image data that cannot be written is generated because one write area is filled, control is performed so that the image data that cannot be written is written to an empty area of another write area.

  As another aspect of the image forming method according to the present invention, the memory device is configured as an assembly of a plurality of memory ICs, and the image data writing control step performed by the control unit includes the image data writing instruction. It is preferable that the same memory IC is not continuously performed.

  According to the present invention, since the memory area can be used effectively, registration correction can be realized with a memory device having a small capacity even when the maximum correction amount is the same as the conventional one. Therefore, it is possible to realize a low-cost image forming apparatus.

  The best mode for carrying out the present invention will be described with reference to the drawings.

Embodiment 1
In image forming apparatuses such as printers, facsimiles, and color copiers, two-dimensional images such as originals, photographs, and paintings stored on paper by a document scanner are separated into pixels and stored in a memory device for enlargement / reduction / correction. After the electrical editing, etc., a permanent visible image is formed on the recording paper using various energy such as light, heat, electricity, magnetism, chemical reaction, pressure, etc. Has been done. In particular, in recent image output systems, high-quality color copiers, printers, and the like have been developed by adopting optical output system image output technology.

  Therefore, in this embodiment, an image forming apparatus having a laser scanner type optical scanning system as shown in FIG. 1 will be described as an example. FIG. 1 is a diagram showing a configuration example of a general laser scanner type optical scanning system. Such a laser scanner has a rotating polygon mirror called a polygon mirror 30, and can scan the laser beam 32 by being directly connected to the scanner motor 31 and rotating. The laser beam 32 reflected by the polygon mirror 30 is projected onto an F-θ lens 35 including a spherical lens 33 and a toric lens 34. The F-θ lens 35 is a special lens for converting constant angular velocity information into constant velocity linear information, and is a lens in which the focal length F is proportional to the angle θ. The laser beam 32 projected onto the F-θ lens 35 is projected onto the photosensitive drum 37 via the reflection mirror 36.

  In the image forming apparatus having a general laser scanner type optical scanning system as described above, one or two laser beams 32 are projected on the photosensitive drum 37 in one scan, and the resolution thereof is about 600 dpi. As a memory device used in such an image forming apparatus, a memory device similar to that shown in the background art can be used. However, as a characteristic feature of the present embodiment, it differs from a conventional memory device. Since the memory area can be efficiently used effectively, the memory device can be downsized.

  FIG. 2 is a diagram for explaining a control method of the memory device according to the present embodiment. As described in the background art, when the image data written in the memory device 44 requires correction such as registration correction, the writing range of the image data occupying the memory device 44 is, for example, a trapezoidal shape 46. Will be shown. That is, image data that requires registration correction includes a color misregistration correction amount based on information for correcting relative positional deviation between colors in color image formation. Therefore, in the prior art, it was necessary to secure the range of the reference numeral 48, which is a memory capacity corresponding to the maximum correction amount.

  However, in the present embodiment, of the image data writing area to the memory device 44, the triangular area indicated by reference numeral 40 is an empty area of the memory IC (semiconductor memory element) (Mem5) in the fifth row. It was decided to move to a triangular area indicated by reference numeral 42. That is, according to the present embodiment, by effectively using the free space 47 of the memory device 44 that has not been used effectively, the memory IC (Mem1) of the first row to the memory IC ( It is possible to reduce the number of memory ICs required up to six until Mem6) to five from the first row of memory ICs (Mem1) to the fifth row of memory ICs (Mem5). Therefore, the range of the reference numeral 48, which is the memory capacity that must be ensured by the prior art, can be reduced to the range indicated by the reference numeral 49.

  In the case of the memory device 44 illustrated in FIG. 2, writing to the memory IC is performed by having a counter in the main scanning direction and a counter in the sub scanning direction. In the main scanning direction, each region has a main scanning direction counter of 76 to 116 counters. On the other hand, a two-dimensional address indicating the position of the image data in the main scanning direction and the sub-scanning direction is set on the image data side. Writing means for writing image data to the memory device 44 writes the image data on the memory device 44 after obtaining a two-dimensional address of the image data. When the writing area of the image data comes to the protruding area of the triangle indicated by reference numeral 40, the writing destination of the image data is moved from the protruding area of the triangle indicated by reference numeral 40 to the empty area of the triangle indicated by reference numeral 42. The writing destination is changed by converting the counter in the main scanning direction and the counter in the sub scanning direction in the protruding area indicated by reference numeral 40 into an empty area indicated by reference numeral 42 by calculation. At this time, the two-dimensional address indicating the position of the image data in the main scanning direction and the sub-scanning direction is also address-converted.

  On the other hand, when the image data written in the memory device 44 is read, correct image output is possible by performing reverse address conversion and counter calculation. That is, the reading means for reading image data from the memory device 44 can acquire the two-dimensional address and specify the reading range in the main scanning direction and the sub scanning direction.

  The address conversion and counter calculation are performed by the control unit 56 described later. The control unit 56 converts the two-dimensional address acquired by the writing unit or reading unit, and writes the image data to the memory device 44. Control or read control is performed.

  As described above, the write control of the image data is performed so as to fill the empty area of the memory device 44 by performing the address conversion of the two-dimensional address and the counter operation according to the usage state of the memory device 44, and the efficiency of the memory device 44 Use is realized.

  The specific contents of such address translation will be described with reference to the block diagram shown in FIG. FIG. 3 is a block diagram for explaining the overall configuration of the image forming apparatus.

  In the image forming apparatus according to the present embodiment, when each color data constituting the image data is input, the processing from the data format conversion 50 to the memory write data format conversion 53 is performed, and the memory device in which the correction in the main scanning direction is performed. The writable color data is formed. In the memory write interface 54, an address is given to each color data. Each color data to which an address is assigned is written into the memory device by the control unit 56 of the image forming apparatus. At this time, the control unit 56 performs an operation so that each color data is written to the memory device without waste. The control unit 56 also performs address conversion when reading each color data. Each color data is read by the memory read interface 58 and then subjected to the sub-scan correction 59 and is output as an appropriate color image by the data output 60.

Embodiment 2
In the first embodiment described above, the present invention has been described by exemplifying an image forming apparatus having a laser scanner type optical scanning system using a general semiconductor laser. In the present embodiment, an image forming apparatus having a high resolution using a surface emitting semiconductor laser VCSEL developed and put into practical use by the applicant will be described as an example.

  FIG. 4 is a diagram showing a device configuration of an image forming apparatus using the surface-emitting type semiconductor laser VCSEL 65 targeted by the present embodiment. The surface-emitting type semiconductor laser VCSEL 65 provided in such an image forming apparatus realizes multi-beam scanning laser light 66 and high-density integration of elements in order to improve the resolution from the conventional semiconductor laser. Conventionally, one or two laser beams are projected on the photosensitive drum in one scan, and the resolution is about 600 dpi. By adopting this surface emitting semiconductor laser VCSEL65, 32 laser beams per scan are used. Laser light 66 is projected onto the photosensitive drum 67 to achieve a resolution of 2,400 dpi.

  The memory device used in the image forming apparatus using the surface-emitting type semiconductor laser VCSEL65 realizing the high resolution as described above is required to have a more efficient memory control technique such as improvement of writing / reading efficiency. become.

  By the way, in the invention shown in the first embodiment, the image data located in the protruding area is written in an arbitrary empty area of the memory device by address conversion. However, the memory IC has a restriction that data cannot be read simultaneously when data at different addresses is written in the same memory IC. Further, in an image forming apparatus using the surface emitting semiconductor laser VCSEL65, it is required to read out 33 lines of image data simultaneously. The present embodiment provides a memory control technique that can realize a high-resolution image forming apparatus of 2,400 dpi in consideration of the above memory conditions.

  This embodiment will be described with reference to FIGS. FIG. 5 is a diagram showing image data written in the memory device 84 included in the image forming apparatus according to the present embodiment. For ease of explanation, magenta (M) and cyan (C) are only in the sub-scanning direction. The case where the generated deviation is corrected is illustrated. The image data shown in FIG. 5 is a magenta (M) image data 72M and a cyan (C) image data 72C obtained by performing a predetermined image calculation after taking an input image and performing registration correction. As shown. FIG. 6 is a diagram for explaining the image forming apparatus according to the present embodiment.

  What is characteristic in the present embodiment is that in the memory device 84 configured as an aggregate of a plurality of memory ICs (Mem1 to Mem6), the write area is divided into at least two or more for each memory IC. is there. In addition, the image data written in the memory device 84 is also divided into the number of areas corresponding to the divided writing areas of the memory device 84. Will be written for each embedded area. In the present embodiment, the case where the memory device 84 and the image data are divided into two parts will be described as an example. That is, in the case of the memory device 84 shown in FIG. 6, each memory IC (Mem1 to Mem6) is divided into two with the broken line 85 as a boundary line, and there are two write areas 85a and 85b. In the case of the image data shown in FIG. 5, the image data is divided into two with the broken line 75 as a boundary line, and there are two divided image data 75a and 75b.

  In the image data 75a and 75b divided into two as described above, the divided image data 75a is written in the writing area 85a and the divided image data 75b is written in the writing area 85b. In this embodiment, the divided image data 75b is stored in the memory of the first row in order to eliminate the restriction of the memory IC that data cannot be read simultaneously when data at different addresses is written in the same memory IC. Writing is started from the IC (Mem1), and the divided image data 75a is written from the memory IC (Mem5) on the fifth row. In such a configuration, the divided image data indicated by the reference numeral 75b has a larger correction amount than the divided image data indicated by the reference numeral 75a, and thus the capacity of the image data is large. Further, in such divided image data 75b having a large correction amount, an area 80 that cannot be written to the memory may occur. Thus, when the writing area of the divided image data 75b comes to the protruding area of the triangle indicated by reference numeral 80, the writing destination of the protruding image data is indicated by reference numeral 82 from the protruding area of the triangle indicated by reference numeral 80. Move to a triangular free area. The change of the writing destination is the same as that described in the first embodiment, and the control unit 56 sets the two-dimensional address of the image data in the protruding area indicated by the reference numeral 80, the counter in the main scanning direction, and the counter in the sub scanning direction. This is performed by converting the address into the empty area indicated by reference numeral 82 by the calculation performed by the above. That is, the control unit 56 generates image data (image data in the protruding area of the triangle indicated by reference numeral 80) that cannot be written by filling one writing area (the writing area 85b in FIG. 6). This image data that cannot be written is instructed to be written in a blank area in another writing area (a triangular blank area indicated by reference numeral 82). Since reading is also performed by address conversion similar to that in the first embodiment, detailed description thereof is omitted.

Embodiment 3
In the present embodiment, an image forming apparatus having an LED array type optical scanning system as shown in FIG. 7 will be described as an example. FIG. 7 is a diagram illustrating a configuration example of a general LED array type optical scanning system. The LED array 90 is formed by accumulating 8 to 16 infrared LEDs per millimeter and arranging them in a linear array, and is used in combination with the condensing optical fiber 92. This embodiment shows that the present invention can also be applied to an image forming apparatus having an LED array type optical scanning system as shown in FIG.

  This embodiment will be described with reference to FIG. FIG. 8 is a diagram for explaining the image forming apparatus according to the present embodiment.

  In the case of an LED array type optical scanning system, pixel-decomposed image data is written to the memory device 104 in units of line-shaped image data arranged in a line. Therefore, a problem in using the LED array type optical scanning system is a limitation of the memory IC that data cannot be read simultaneously when data of another address is written in the same memory IC. That is, as described above, if each memory IC is installed in parallel with the main scanning direction in which image data is written, data at different addresses is written to the same memory IC one by one. . With such a configuration, it takes a long time to read out image data.

  Therefore, in this embodiment, a plurality of memory ICs (Mem1 to Mem4) constituting the memory device 104 are arranged in a direction perpendicular to the main scanning direction in which image data is written, and image data is written by the same memory IC. It was decided not to do it continuously. By adopting such a writing method, image data can be read at a time in the order of decomposed pixels a, b, c, d, e, f,.

  Also in this embodiment, in order to efficiently use the writing area of the memory device 104, address conversion by the control unit is performed, and image data writing control is performed so as to fill the empty area generated in the memory device 104. It is possible. As described above, according to the image forming apparatus of the present invention, since the memory device 104 can be effectively used, it is possible to reduce the cost by downsizing the memory device 104.

  In the first to third embodiments described above, the image forming apparatus having the tandem configuration is shown, and the case where the image data includes a shift correction amount such as registration correction is described as an example. However, the present invention is not limited to those described in the first to third embodiments. For example, the present invention can be applied to image data including correction amounts such as rotation correction and enlargement / reduction correction, and is a multi-photosensitive color copying machine as shown in FIG. 9 and does not require registration correction. The present invention can also be applied to a type image forming apparatus.

  In the first to third embodiments, the case where a single-port SRAM (Static Random Access Memory) is adopted as the memory IC has been described as an example. However, the present invention is not limited to a dual-port SRAM or a DRAM (Dynamic Random Access Memory). The present invention is also applicable to a non-volatile magnetic memory such as a semiconductor memory such as) or an MRAM (Magnetic Random Access Memory).

It is a figure which shows the structural example of the optical scanning system of a general laser scanner system. 3 is a diagram for explaining a control method of the memory device in Embodiment 1. FIG. 1 is a block diagram for explaining an overall configuration of an image forming apparatus. It is a figure which shows the apparatus structure of the image forming apparatus using the surface emitting semiconductor laser VCSEL which 2nd Embodiment is object. 6 is a diagram illustrating image data written in a memory device included in an image forming apparatus according to a second embodiment. FIG. FIG. 4 is a diagram for explaining an image forming apparatus according to a second embodiment. It is a figure which shows the structural example of the optical scanning system of a general LED array system. FIG. 10 is a diagram for explaining an image forming apparatus according to a third embodiment. 1 is a diagram showing a multi-photosensitive color copying machine to which the present invention is applicable. It is a diagram showing a conventional tandem image forming apparatus when registration correction is not performed. It is a figure which shows the image forming apparatus of the conventional tandem structure in the case of performing registration correction. It is a figure which shows the state of the memory device which written image data in the conventional image forming apparatus.

Explanation of symbols

  10, 14 Acquired image data, 11 recording paper, 12 output image, 16 image without deviation, 20 input image, 21 image calculation, 22M, 72M magenta (M) image data, 22C, 72C cyan (C) image data 24, 44, 84, 104 Memory device, 26, 46 Trapezoidal shape, 30 Polygon mirror, 31 Scanner motor, 32, 66 Laser light, 33 Spherical lens, 34 Toric lens, 35 F-θ lens, 36 Reflecting mirror, 37 , 67 Photosensitive drum, Mem1 to Mem6 Memory IC, 47 Memory device free space, 50 Data format conversion, 53 Memory write data format conversion, 54 Memory write interface, 56 Control unit, 58 Memory read interface, 59 Sub-scan correction, 60 Data output, 65 pages Type semiconductor laser VCSEL, 75, 85 broken line, 75a, 75b divided image data, 85a, 85b writing area, 80 protruding area, 82 empty area, 90 LED array, 92 condensing optical fiber, a, b, c, d, e, f Decomposed pixels.

Claims (4)

A memory device for storing image data;
Writing means for obtaining a two-dimensional address indicating the position of the image data in the main scanning direction and the sub-scanning direction and writing the image data in the memory device;
Reading means for acquiring the two-dimensional address, specifying a reading range in a main scanning direction and a sub-scanning direction, and reading image data from the memory device;
A control unit that converts a two-dimensional address acquired by the writing unit or the reading unit and controls writing or reading of image data to or from the memory device, and fills an empty area of the memory device. A control unit that performs address conversion of a two-dimensional address according to the usage status of the memory device by performing data write control ;
Bei to give a,
The memory device is configured as an aggregate of a plurality of memory ICs,
Each of the memory ICs has an address corresponding to a position in the main scanning direction, and is divided into at least two write areas,
The image data is divided into the number of areas corresponding to the number of divided writing areas of the memory IC in the main scanning direction;
The control unit performs write control so that the write start positions in the memory devices of the divided image data are different from each other, and one write area is filled up. When image data that cannot be written is generated, control is performed so that the image data that cannot be written is written to an empty area of another writing area
An image forming apparatus. The image forming apparatus according to claim 1.
The image data includes a color misregistration correction amount based on the relative misregistration correction information between colors in color image formation,
An image forming apparatus, wherein the address conversion performed by the control unit performs image data writing control so as to fill an empty area of the memory device caused by a color misregistration correction amount. This is an image forming method used when storing acquired image data in a memory device and obtaining desired image data output by performing a predetermined correction to efficiently store image data in the memory device by a computer. And
  Writing means for writing image data into the memory device, obtaining a two-dimensional address indicating the position of the image data in the main scanning direction and the sub-scanning direction;
  A control unit that performs writing control of image data to the memory device converts the two-dimensional address acquired by the writing unit according to the usage status of the memory device, and fills an empty area of the memory device. Performing write control;
  A control unit that performs reading control of image data with respect to the memory device converts the two-dimensional address acquired by a reading unit that reads image data from the memory device;
  The reading means acquiring the address-converted two-dimensional address and specifying a reading range in a main scanning direction and a sub-scanning direction;
  Have
  The memory device is configured as an aggregate of a plurality of memory ICs,
  Each of the memory ICs has an address corresponding to a position in the main scanning direction, and is divided into at least two write areas,
  The image data is divided into the number of areas corresponding to the number of divided writing areas of the memory IC in the main scanning direction;
  In the step of performing the write control, the control unit that performs the write control performs the write control so that the write start positions of the divided image data in the memory devices are different from each other, and When image data that cannot be written is generated by filling one writing area, control is performed so that the image data that cannot be written is written to an empty area of another writing area.
  An image forming method. The image forming method according to claim 3 .
The image data includes a color misregistration correction amount based on the relative misregistration correction information between colors in color image formation,
The address conversion when the control unit performs the image data writing control step includes a step of performing image data writing control so as to fill an empty area of the memory device caused by a color misregistration correction amount. Forming method .

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