JP2006205613A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device which achieves both high-image quality printing and high-speed printing while suppressing increase of loadage of line memories. <P>SOLUTION: The color printer 100 in a high-speed printing mode reads out image-processed data corresponding to three lines from an image processing section 50, and stores the data in the line memories 61K, respectively. Then in synchronization with output of fourth-line data, the data corresponding to the three lines are read out from the line memories 61K to be output to respective laser diodes (LD). In other words, the line memories 61K are for use as a buffer for multi-beam outputting in optical scanning. On the other hand, if the color printer is in a high-image quality printing mode, data under image processing, corresponding to three lines are stored in the line memories 61K. Then in synchronization with processing of a fourth-line data, they are output to an image processing section 50. In other words, the line memories 61K are for use as a buffer for processing an image in the image processing section 50. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus that forms an image by electrophotography. More specifically, the present invention relates to a multi-beam image forming apparatus that performs optical scanning using a plurality of light emitting elements.

  2. Description of the Related Art Conventionally, a multi-beam image processing apparatus that simultaneously writes images for a plurality of lines with a plurality of laser diodes has been proposed (for example, Patent Document 1). In a multi-beam image processing apparatus, image data is processed in parallel by a line memory and exposed to an image carrier such as a photosensitive member with a plurality of beams. Thereby, it is possible to cope with high-speed printing while suppressing the rotation speed of the polygon motor.

  In a multi-beam type image processing apparatus, output data is stored in a line memory, and data of a plurality of lines is collected and output to a laser diode group at a predetermined timing. For this reason, a line memory corresponding to at least n-1 beams is required for the print data output unit, which is the final data output means. That is, in the case of the four-beam configuration for each color, it is necessary to mount a memory of 3 (4 beams-1) × 4 (YMCK 4 colors) = 12 lines. Of course, as the number of beams increases, it is necessary to increase the number of memories accordingly.

On the other hand, the image processing unit also needs to process image data for a plurality of lines when performing filter processing such as smoothing and sharpness. Therefore, a line memory for a plurality of lines is required. In general, as the number of lines that can be processed simultaneously increases, image processing with higher accuracy can be performed. In recent image processing apparatuses, many line memories are mounted in order to meet the demand for higher image quality.
Japanese Patent Laid-Open No. 11-10943

  However, the conventional image processing apparatus described above has the following problems. In other words, in an ASIC based on pipeline processing, the line memory cannot be shared. For this reason, it is necessary to separately mount a line memory for image processing and a line memory for multi-beam output. For this reason, in a multi-beam image forming apparatus, it is necessary to increase the line memory in order to further improve the image quality. That is, in a multi-beam image forming apparatus, in order to cope with both high image quality and high speed printing, a very large number of line memories must be installed. Therefore, the configuration becomes complicated and the cost of the ASIC increases.

  The present invention has been made to solve the problems of the conventional image processing apparatus described above. That is, an object of the present invention is to provide an image forming apparatus that can cope with both high image quality and high-speed printing while suppressing an increase in the amount of line memory mounted.

  An image forming apparatus for solving this problem is an image forming apparatus that includes a light emitting unit including a plurality of light emitting elements and forms an image by scanning a light beam emitted from the light emitting unit. Image processing means for performing image processing, storage means for storing data, line data for reading data from the image processing means for each line, and selecting and storing a storage area in the storage means for each read data It is characterized by having input means and line data output means for reading out data line by line from the storage means means and selecting an output destination for each read data.

  An image forming apparatus according to the present invention is a multi-beam image forming apparatus including a plurality of light emitting elements, and includes image processing means for performing image processing (for example, filter processing such as smoothing) on image data; Storage means (for example, a line memory) for storing data for n lines (n is a natural number) for each line is provided. The capacity of the storage means may be only for one line or may be for a plurality of lines. The storage means stores data for each line of the image data in the main scanning direction.

  The image forming apparatus according to the present invention further includes a line data input unit for storing data in the storage unit, and a line data output unit for reading data from the storage unit. The line data input means reads image data line by line from the image processing means, and selects a storage area in the data storage means. Then, data is input to the storage area. The line data output means reads data from the storage means for each line. Then, an output destination is selected for each storage area.

  In other words, in the image forming apparatus of the present invention, the output means of the data stored in the storage means can be selected by the line data output means, so that the storage means can be used for a plurality of uses. For example, if the data output destination is a light emitting means, it can be used as a buffer for performing multi-beam output. That is, the printing speed can be increased. If the data output destination is an image processing unit, it can be used as a buffer for performing image processing. That is, the capacity of the line memory that can be used in the image processing unit is large, and high image quality can be achieved.

  Specifically, for example, it is possible to switch between a first mode that prioritizes printing speed (high-speed printing mode) and a second mode that prioritizes image quality (high image quality mode). In the first mode, the line data input means stores the image-processed data in the storage means, and the line data output means outputs the data stored in the storage means to the light emitting means. On the other hand, in the second mode, the data being processed by the line data input means is stored in the storage means, and the data stored in the storage means is output by the line data output means to the image processing means.

  That is, in the first mode, data after image processing is stored in the storage means by the line data input means. The line data output means outputs the stored data in the storage means to the light receiving means. Accordingly, the storage means is used as a buffer for multi-beam output in the light emitting means. That is, the printing speed can be increased. On the other hand, in the second mode, the data being processed by the line data input means is stored in the storage means. The line data output means outputs the stored data in the storage means to the image processing unit. Therefore, the storage means is used as a buffer for image processing in the image processing means. In other words, high image quality is achieved. Thus, the usage of the storage means can be switched by switching the operations of the line data input means and the line data output means for each mode. That is, the storage means can be used as a buffer for multi-beam output in the light emitting means or as a buffer for image processing in the image processing means. Therefore, both functions can be realized without increasing the capacity of the storage means.

  Further, for example, the line data input means stores the data being processed in the first area of the storage means, and stores the data after the image processing in the second area of the storage means. May output the data stored in the first area to the image processing means and output the data stored in the second area to the light emitting means.

  That is, the storage means is set with a first area and a second area, the first area is used as a buffer for image processing in the image processing means, and the second area is for multi-beam output. Used as a buffer for Thus, by switching the operation of the line data input means and the line data output means for each region, the storage means can be used as a buffer for multi-beam output in the light emitting means, or a buffer for image processing in the image processing means. Can also be used. Therefore, both functions can be realized without increasing the capacity of the storage means, and the cost increase is suppressed. Then, by making the occupation ratio between the first area and the second area variable, it is possible to perform a print setting with a high degree of freedom without increasing the capacity of the storage means.

  According to the present invention, the storage means (line memory) can be used both as a buffer for multi-beam output and as a buffer for image processing. Therefore, in the image forming apparatus of the present invention, both functions are realized by appropriately switching the use of the line memory, instead of providing a dedicated line memory for realizing both the high image quality and the high-speed printing functions. is doing. Accordingly, there is provided an image forming apparatus that can cope with both high image quality and high-speed printing while suppressing an increase in the amount of line memory mounted.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of an image forming apparatus according to the invention will be described with reference to the drawings. In this embodiment, the present invention is applied to a tandem type color printer.

  As shown in the configuration diagram of FIG. 1, the color printer 100 according to the present embodiment includes a scanning unit 10 that reads a document image, an AD conversion unit 20, and a printer controller 30 that acquires information from an external information terminal device (such as a PC). A color conversion unit 40 that converts RGB data into CMYK data, an image processing unit 50 that performs image processing such as smoothing processing and area correction processing, and print data output units 60C and 60M that output a print signal for each laser diode. , 60Y, 60K.

  Next, the operation of the color printer 100 will be described. First, an RGB image of a document read by the scanner unit 10 or an RGB image transmitted from a PC or the like is sent to the color conversion unit 40. That is, in the case of input from the scanner unit 10, a document image read and photographed by the scanner unit 10 is sent to the color conversion unit 40 via the AD conversion unit 20. In the case of input from an external information terminal device such as a PC, the RGB image is sent to the color conversion unit 40 via the printer controller 30.

  In the color conversion unit 40, the input RGB image is converted into CMYK data, and the CMYK data is output to the image processing unit 50. The image processing unit 50 performs various types of image processing, and outputs the results to the print data output units 60C, 60M, 60Y, and 60K corresponding to the respective colors. Each print data output unit outputs a plurality of lines of data simultaneously. The output data is converted into a beam output by a laser diode (LD). As a result, a latent image is formed on the photoreceptor, and an image is formed through development.

  The color printer 100 of this embodiment can select a high-speed printing mode that prioritizes printing speed and a high-quality mode that prioritizes image quality. The operations of the image processing unit 50 and the print data output units 60C, 60M, 60Y, and 60K are different for each mode. Hereinafter, the details of each operation will be described separately for the high-speed printing mode and the high-quality mode. For simplification of explanation, only the K color output is described in the following explanation. For other colors, the same operation as for the K color is performed.

  First, the high-speed printing mode will be described. FIG. 2 shows the flow of data when output is performed in a multi-beam configuration of 4 beams / 1 color in the high-speed printing mode. In the high-speed printing mode, the line memory 61K is used as a buffer for multi-beam output.

  The color printer 100 according to this embodiment includes four LD1, LD2, LD3, and LD4 for each color. The image processing unit 50 includes line memories 51 for n lines (n is a natural number). The image processing unit 50 uses the line memory 51 to develop a plurality of lines of data in parallel and perform image processing such as smoothing processing. The print data output unit 60K includes a line memory 61K for three lines, an input data control unit 62K that distributes data to each line memory, and an output destination of data stored in each line memory. And an output data control unit 63K for distribution.

  Data subjected to image processing by the image processing unit 50 is input to the input data control unit 62K line by line, and an appropriate storage destination is selected by the input data control unit 61K and sent to the line memory 61K. In the line memory 61K, data is written for each line. That is, the first line data is written into the line memory 1, the second line data is written into the line memory 2, and the third line data is written into the line memory 3. When the data on the fourth line is output toward the LD 4, the data written in the line memory 1, the line memory 2, and the line memory 3 are read simultaneously. That is, the data from the first line to the third line is stored in the line memory 61K, but the data on the fourth line is not stored in the line memory 61K but is sent to the LD 4 as it is. The data read from the line memory 61K is output to the LD1, LD2, and LD3, respectively, after an appropriate output destination is selected by the output data control unit 63K. As a result, data for four lines is output simultaneously, and printing speed is increased.

  Next, the high image quality mode will be described. FIG. 3 shows a data flow when the image is output in the high image quality mode and the beam configuration of 1 beam / 1 color. In the high image quality mode, the line memory 61K is used as a buffer for image processing. This is different from the high-speed printing mode used as a buffer when performing multi-beam output of data. Also, the point of output with a beam configuration of one beam is different from the high-speed printing mode of output with a beam configuration of four beams. That is, in this embodiment, only LD4 is used among LD1, LD2, LD3, and LD4, and other LDs are not used.

  In the high image quality mode, data being processed is input to the input data control unit 62K, and an appropriate storage destination is selected by the input data control unit 61K and sent to the line memory 61K. In the line memory 61K, data is written for each line. That is, the first line data is written into the line memory 1, the second line data is written into the line memory 2, and the third line data is written into the line memory 3. Then, when the data of the fourth line is processed in the image processing unit 50, the data written in the line memory 1, the line memory 2, and the line memory 3 are read. The data read from the line memory 61K is output to the image processing unit 50 after an appropriate output destination is selected by the output data control unit 63K. As a result, the image processing unit 50 can handle n + 3 line data. Therefore, high image quality can be achieved.

  The data processed by the image processing unit 50 is output to the LD 4 without going through the print data output unit 6K. The output data is converted into a beam output by the LD 4 and a latent image is formed on the photoconductor. In the high image quality mode, the number of LDs to be driven is ¼ compared to the high speed printing mode, so that a normal image is formed by setting the rotation speed of the photosensitive member to ¼.

[Application example]
When a plurality of lines can be stored in the line memory 61K as in the embodiment, the line memory 61K can be distributed and used by the image processing function and the print data output function. Hereinafter, as an application example, a case where the line memory 61K capable of storing three lines uses two lines for the image processing function and one line for the print data output function (intermediate mode) will be described. FIG. 4 shows the flow of data when the intermediate mode is output with the beam configuration of 2 beams / 1 color.

  In the intermediate mode, as in the high image quality mode, data being processed is input to the input data control unit 62K, and an appropriate storage destination is selected by the input data control unit 61K and sent to the line memory 61K. In the line memory 61K, the selected data is written for each line. In the intermediate mode of this embodiment, since only two lines of the line memory 61K are used, the first line data is written to the line memory 1 and the second line data is written to the line memory 2, respectively. Do not access

  Then, when the data for the third line is processed in the image processing unit 50, the data written in the line memory 1 and the line memory 2 are simultaneously read out and output to the image processing unit 50. As a result, the image processing unit 50 can handle n + 2 line data. Therefore, the image quality is improved as compared with the case where only the line memory 51 in the image processing unit 5 is used.

  Further, the first line of the data subjected to image processing by the image processing unit 50 is input to the input data control unit 62K, an appropriate storage destination is selected by the input data control unit 61K, and the line of the line memory 61K is selected. It is sent to the memory 3. Then, when the data of the second line is output toward the LD 4, the data written in the line memory 3 is read simultaneously. That is, the data for the first line is stored in the line memory 61K, and the data for the fourth line is sent to the LD 4 as it is without being stored in the line memory 61K. The data read from the line memory 61K is selected by the output data control unit 63K and then output to the LD3. As a result, the data for the first line is output simultaneously with the second line, and the printing speed can be increased compared to the case where only one LD is used.

  Data processed by the image processing unit 50 is converted into a beam output by the LD 3 and LD 4 to form a latent image on the photoreceptor. In the high image quality mode, the number of LDs to be driven is halved compared to the high speed printing mode, so that a normal image is formed by halving the rotational speed of the photoconductor.

  The distribution of the line memory 61K in the intermediate mode is not limited to this. For example, as the second intermediate mode, the line memory 1 may be used for image processing, and the line memory 2 and the line memory 3 may be used as print outputs.

  As described above in detail, the color printer 100 according to this embodiment stores data for three lines after image processing in the line memory 61K in the high-speed printing mode, and synchronizes with the output of the fourth line. It is going to output to. That is, the line memory 61K is used as a buffer for multi-beam output in optical scanning. On the other hand, in the high image quality mode, data for three lines during image processing is stored in the line memory 61K and is output to the image processing unit 50 in synchronization with the processing for the fourth line. That is, the line memory 61K is used as a buffer for image processing in the image processing unit 50.

  Thus, by switching the operation of the print data output unit 60K for each mode, the line memory 61K can be used as a buffer for multi-beam output or a buffer for image processing. Therefore, in the multi-beam image forming apparatus, it is possible to further improve the image quality without increasing the capacity of the line memory. Therefore, an image forming apparatus that can cope with both high image quality and high-speed printing while suppressing an increase in the amount of line memory mounted has been realized.

  Further, like the color printer of the application example, the line memory 61 may be distributed for image processing and multi-beam use. As a result, it is possible to adjust high-speed printing and high image quality, and it is possible to perform print settings with a high degree of freedom without increasing the capacity of the line memory.

  Note that this embodiment is merely an example, and does not limit the present invention. Therefore, the present invention can naturally be improved and modified in various ways without departing from the gist thereof. For example, in the embodiment, four LDs are provided, but the present invention is not limited to this. In other words, the present invention can be applied as long as it has two or more LDs and can perform a plurality of lines in one scan.

  Further, the present invention is not limited to a color laser printer. That is, any apparatus having an optical scanning device that simultaneously scans a plurality of light beams can be applied. For example, the present invention can be applied to a copying machine, a FAX, and the like. It can also be applied to a monochrome machine.

  In the embodiment, output data from the LD 4 is directly input from the image processing unit 50, but the present invention is not limited to this. For example, as shown in FIG. 5, the fourth line may be stored in the line memory, and all output data may be controlled by the output data control unit 62K.

1 is a diagram illustrating a module configuration of an image forming apparatus according to an embodiment. It is a figure which shows the data flow in ASIC in a high-speed printing mode. It is a figure which shows the data flow in ASIC in a high image quality mode. It is a figure which shows the data flow in ASIC in intermediate | middle mode. It is a figure which shows the flow of data when controlling all the outputs by an output data control part.

Explanation of symbols

50 Image processing unit (image processing means)
51 Line memory 60K Print data output unit 61K Line memory (storage means)
62K input data control unit (line data input means)
63K output data control unit (line data output means)
LD Laser diode (light emitting element)
100 color printer (image forming device)

Claims (4)

In an image forming apparatus having a light emitting means having a plurality of light emitting elements and forming an image by scanning a light beam emitted from the light emitting means,
Image processing means for performing image processing;
Storage means for storing data;
Line data input means for reading out data for each line from the image processing means, and selecting and storing a storage area in the storage means for each read data;
An image forming apparatus comprising: line data output means for reading out data for each line from the storage means and selecting an output destination for each read data. The image forming apparatus according to claim 1,
Switching between the first mode and the second mode is possible,
In the first mode,
The image data processed by the line data input means is stored in the storage means,
Outputting the data stored in the storage means to the light emitting means by the line data output means;
In the second mode,
The data being processed by the line data input means is stored in the storage means,
An image forming apparatus, wherein the line data output means outputs data stored in the storage means to the image processing means. The image forming apparatus according to claim 1,
The line data input means includes:
Storing the data being processed in the first area of the storage means;
Storing the image-processed data in the second area of the storage means;
The line data output means includes
Outputting data stored in the first area to the image processing means;
An image forming apparatus that outputs data stored in the second area to the light emitting unit. The image forming apparatus according to claim 3,
Switching between the first mode and the second mode is possible,
In the first mode,
The image data processed by the line data input means is stored in the second area of the storage means,
In the second mode,
An image forming apparatus characterized in that data during image processing is stored in the first area of the storage means by the line data input means.

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