JP2011042110A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the following problems: when a gradation pattern is copied and diverted, it is necessary to update the gradation pattern when the color value of the gradation pattern to be diverted is changed in a sub-scanning direction, and processing speed becomes low since rendering is performed on a per-pixel rendering basis. <P>SOLUTION: As a gradation pattern forming method, an image forming apparatus includes: a means for storing the gradation as a plurality of monochromatic paint-out data; and a means for switching the processing according to the number of changed color channels when the color value is changed in the sub-scanning direction. The gradation pattern forming method is characterized in that, by using a monochromatic paint-out link structure, color value data is not stored for each of pixels. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image forming apparatus, an image forming method, and a program for executing the image forming method.

  In general, gradation drawing includes a drawing method in which the color gradation changes in the horizontal direction of the paper and a drawing method in which the color gradation changes in the vertical direction. In addition, the gradation includes a gradation whose color changes in an oblique direction and a gradation whose gradation changes in a circular shape toward the center of the object to be drawn. In the scanline renderer, when drawing various gradations, it is necessary to calculate for each gradation of pixels on the scanline. Therefore, a technique for changing the drawing method according to the type of gradation has been proposed.

  As a conventional gradation drawing method, there is a drawing method for enlarging a one-pixel-wide image vertically or horizontally by drawing as an image instead of a gradation when the same color value continues in the horizontal and vertical directions (Patent Document). 1). In this method, by enlarging the image, it is possible to draw an enlarged width with only the amount of calculation for one pixel, and high-speed drawing is possible. As for the method of drawing an oblique gradation, the gradation pattern on the first line is used to draw the gradation pattern shifted in the main scanning direction for drawing the gradation following the sub-scanning direction (Patent Document 2). As a result, it is possible to reduce processing for calculating and creating an oblique gradation for each line in the sub-scanning direction.

JP 2008-279626 A JP 2003-223644 A

  However, the following problems can be considered in the above method.

  In Patent Document 2, which is a method for increasing the speed of diagonal gradation, when the color value is different from the gradation of the first line in the sub-scanning direction, the gradation pattern cannot be used for drawing (FIG. 11). Further, when the gradation pattern data to be created in advance is large, a large amount of memory capacity is required to hold it in the memory.

  When drawing data with a horizontal gradation on the entire background, the method of Patent Document 1 has a problem in that performance deteriorates when performing a scanline renderer. The scan line renderer needs to calculate and draw the color information of each pixel when the color gradation differs in the scanning direction. For this reason, in the scanline renderer, if a horizontal gradation is generated in 1-pixel-wide image data and enlarged in the sub-scanning direction, the processing becomes slow.

  In the present invention, as a technique for solving the above problem, a method of creating a gradation pattern when the gradation of an oblique gradation changes in the sub-scanning direction and a method of switching the gradation drawing method according to the color difference in the sub-scanning direction are proposed. . We also propose a method for drawing a gradation at high speed when the entire background of the page has a horizontal gradation.

When drawing a horizontal gradient,
Means (502) for generating a gradation pattern for one line from the gradation start position;
When drawing a gradation of a pattern different from the gradation pattern created above in the sub-scanning direction (FIG. 11),
In the above means, when adding the color difference of each color channel in the sub-scanning direction, if the number of pixels of each color different in color difference is within a certain threshold (506), the means for adding the color difference for each pixel of the gradation pattern; ,
In the above means, when the color difference of the color channels is added, if the number of color channels and the number of pixels of each color differ from each other when the color difference is updated with a threshold value or more, a new gradation pattern for one line is drawn (507) )When,
An image forming apparatus (102) comprising:

When drawing a horizontal gradation (501), as a method (502) for generating a gradation pattern for one line from the start position of the gradation,
Means for converting the gradation into a plurality of single-color fill data (FIG. 6);
Means for holding a pixel number (602) and a color value (601) in which the color value of each pixel is equivalent;
Means (606) for generating a structure for linking the information of the filled area in the order of drawing in the main scanning in the means;
Means (504) for copying and drawing the gradation pattern generated by the means for each line;
An image forming apparatus (102) comprising:

When the entire print data is a gradation (801, 803) that changes the gradation in the scanning direction,
Means (901) for detecting the gradation;
Means (902) for changing the orientation of the paper using the gradation by 90 degrees;
Means (903) for processing the background as a one pixel wide image (1001) in the main scanning direction by the means;
In the means, means (904) for switching processing (1002) so as to fill in the main scanning direction for each scan line;
Means (905) for returning to the original paper orientation after filling all the pixels by the means;
An image forming apparatus (102) characterized by comprising:

  In the present invention, when drawing a gradation in the horizontal direction, it is possible to select a high-speed drawing method for a gradation in which the color gradation changes in the sub-scanning direction. Also, by changing the gradation to a plurality of single color fills, it is possible to reduce the data cache memory because it does not hold color information in pixel units. As for the gradation of the entire background, the gradation can be drawn at a high speed as an image having a width of 1 pixel by rotating the orientation of the page by 90 degrees.

1 is a block diagram illustrating a configuration of a printer that is an embodiment of a printing apparatus according to the present invention. It is a block diagram which shows the structural example of the controller unit of each apparatus in embodiment. It is a figure which shows an example of a structure of the controller software in embodiment. It is a figure which shows the example of a structure of the scanline renderer in embodiment. It is the flowchart figure which showed the process branch for every gradation pattern of the gradation drawing method in embodiment. It is a figure which shows the structure of the link flat color (LFC) in embodiment. It is the figure which showed the preparation method of the diagonal gradation in embodiment, and the subject of the conventional method. It is a figure when the gradation image of the whole page in embodiment rotates 90 degree | times to the direction of a page. It is the flowchart figure which showed the drawing method of the gradation image of the whole page in execution form. It is the figure which showed the drawing method of the image of 1 pixel width in embodiment. It is the figure which showed the gradation which a color difference produces in the subscanning direction in embodiment.

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

"Printer configuration"
FIG. 1 is a block diagram illustrating a configuration of a printer that is an embodiment of a printing apparatus that implements the present invention.

  A printer controller unit 103, a printer engine unit 105, and an operation panel unit 104 are provided. The printer controller 103 receives code data (various page description languages (hereinafter referred to as PDL)) from an external device 101 such as a host computer (hereinafter referred to as a host). Image data (page information) is generated by analyzing the code data. The generated image data is transmitted to the printer engine unit 105 via the interface. The printer engine unit 105 forms an image indicated by the image data generated by the printer controller unit 103 on a sheet by an electrophotographic process. The printer engine unit 105 includes each mechanism and an engine control unit that performs control related to each printing process (for example, paper feed processing) by each mechanism. The operation panel unit 104 serves as an interface with the user, and constitutes an operation unit for performing an input operation for instructing a desired operation on the printer 102.

“Configuration of Printer Controller”
Next, the configuration of the printer controller unit 103 will be described with reference to FIG.

  The printer controller unit 103 is a CPU 202 for controlling the entire printer controller unit 103, and constitutes an input / output unit for signals exchanged with the external device 101. A RAM 204 is a system work memory for the CPU 202 to operate, and is also an image memory for temporarily storing input image data. Further, the ROM 205 stores system control codes. In addition, the printer controller unit includes a host I / F 203 that performs communication control with the external device 101.

  A raster image processor (RIP) 206 expands PDL data and the like into bitmap data. From the code data input via the host I / F 203, the CPU 202 creates bitmap data that can be processed by the printer engine unit 105 from the RIP 206 according to the control code stored in the ROM 205.

  The bitmap data is transferred to the printer engine unit 105 as a video signal via the engine I / F unit 207. The engine I / F unit 207 constitutes an input / output unit for signals exchanged with the printer engine unit 105 and controls communication with the printer engine unit 105.

  Instructions relating to mode setting and the like issued by operation input from the panel unit 104 (shown in FIG. 1) are input via the operation panel I / F unit 201, and the operation panel I / F unit 201 is connected to the panel unit 104 and the CPU 202. Configure the interface between.

  The CPU 202 controls each block described above according to the mode instructed from the panel unit 104, and this control is executed based on the control code stored in the ROM 205. Each block including the CPU 202 is connected to the system bus 208 so that the CPU can access it. An HDD 209 is a hard disk drive, and stores system software for various processes, input image data, and the like. The gradation drawing method is held in the HDD 209 and can be drawn by storing the program code of this patent in the RAM 204.

"Configuration of controller software"
FIG. 3 is a block diagram illustrating a configuration of controller software that controls the operation of the printing apparatus.

  The printer interface 301 is a means for input / output with the outside. The protocol control unit 302 is means for performing communication with the outside by analyzing and transmitting a network protocol.

  The vector data generation unit 303 generates (vectorizes) vector data that is a rendering description independent of resolution from PDL data.

  The PDL data analysis unit 304 is means for analyzing the PDL data and converting it into intermediate description data (DISPLAY LIST) in a format that is easier to process. The intermediate code generated in the PDL data analysis unit 304 is transferred to the data drawing unit 305 and processed. The data drawing unit 305 expands the intermediate code into bitmap data, and the expanded bitmap data is sequentially drawn in the page memory 306. Here, when there is gradation drawing data in the DISPLAY LIST, the drawing method of this patent is performed.

  The page memory 306 is a volatile memory that temporarily holds bitmap data developed by the renderer.

  The panel input / output control unit 307 controls input / output from the operation panel. The document storage unit 308 is a means for storing a data file including a DISPLAY LIST for each block (job) of the input document, and is realized by a secondary storage device such as a hard disk.

  A scan control unit 309 performs various processes such as correction, processing, and editing on the image data input from the scanner.

  The print control unit 310 converts the content of the page memory 306 into a video signal and transfers the image to the printer engine unit 311. The printer engine unit 311 is a printing mechanism unit for forming a received video signal on a recording sheet as a visible image.

"Configuration of the scanline renderer"
FIG. 4 is a block diagram illustrating a configuration of the scanline renderer 402 in the data drawing unit 305.

  DISPLAY LIST 401 is intermediate code obtained by converting PDL data by the PDL data analysis unit 304. The scanline renderer 402 uses the DISPLAY LIST 401 as input data, and generates bitmap data 407 through the contour writing processing unit 403, the overlap alignment processing unit 404, the color painting processing unit 405, and the color composition processing unit 406. The bitmap data 407 is held in the page memory 306.

  The contour writing processing unit 403 is processing for acquiring contour information from a drawing object included in the DISPLAY LIST 401. The contour information indicates two pieces of information, that is, the starting position of the contour of the drawing object and the contour width. When the contour information acquired by the contour writing processing unit 403 is aligned for one scan line of the image data, the contour coordinate information is sent to the next overlap alignment processing unit 404.

  The overlapping alignment processing unit 404 performs alignment processing so that the drawing objects are arranged in the correct order on the paper surface based on the information on the contour coordinates and the vertical relationship between the overlapping of the drawing objects. The aligned contour information is sent to the color painting processing unit 405 after being aligned for one scan line of the image data.

  The color painting processing unit 405 adds color information to each section divided by the outline with respect to the aligned outline information. The gradation pattern used in the present invention is generated by the color painting processing unit 405. The aligned contour information to which the color information generated by the color processing unit 405 is added is sent to the color composition processing unit 406 after one scan line is prepared.

  The color compositing processing unit 406 includes regions that are separated by contours based on the aligned contour information to which color information is added, and portions that overlap with regions that are separated by other contours. The overlap rule according to DISPLAY LIST 401 is applied to. Overlapping rules include ROP (RasterOPerator) and alpha blending. ROP is a logical operation performed by bits expressing color values on the entire surface side and the back surface side in a region where regions overlap each other. When ROP is specified as the overlapping rule, a result of logical operation performed between color values representing the entire area side and the back area is output. Alpha blending designates the ratio of the ratios of the colors of the entire side and the back side of the two, which are overlapped in the areas delimited by the outline, when the colors are output. The color composition processing unit 406 uses an overlap rule to determine what color is to be output from the entire overlapped area and the back area. Bitmap data 407 is output from the data generated by the color composition processing unit 406 as color information for each pixel of the image data.

  In this embodiment, the efficiency of the gradation drawing speed and the improvement of the speed will be described with reference to the flowchart of FIG. The gradation drawing position is detected based on the DISPLAY LIST 401 generated by the PDL analysis unit 304. It is detected 501 whether the gradation drawn from the data of the DISPLAY LIST 401 is a gradation having different gradations in the horizontal direction. This detection method detects whether there is a difference in gradation in the rasterizing direction by using a calculation formula for creating gradation pixel data in the color painting processing unit 405. The gradation color difference variable is Cxi in the horizontal direction and Cyi (i = 0 to 3) in the vertical direction, and the gradation is changed by adding the respective values. Whether the gradation changes in the sub-scanning direction may be determined from the value of Cyi. Information such as whether the gradation is horizontal or vertical may be added to the DISPLAY LIST 401 in advance. If the gradation does not change in the horizontal direction in the determination 501, the conventional gradation drawing method 507 is used. Conventional gradation drawing methods include a drawing method in units of pixels and a process of enlarging in a rasterizing direction as a one-pixel-wide image.

  When the gradation changes in the horizontal direction, a link flat color (hereinafter referred to as LFC) is created (502). Refer to FIG. 6 for the LFC creation method. The LFC is configured to update the gradation color information 601 and the number of pixels 602 followed by the color information every time the gradation changes. Since LFC does not need to store data for each pixel when reusing gradation pattern drawing data, the cache size can be reduced compared to the conventional case. Also, when drawing, since data to be drawn as image data for each pixel is not sent to the data drawing unit 305 but sent as a plurality of single-color fill data, processing can be reduced when drawing a gradation. . In the LFC configuration method, after detecting the gradation pattern, the color information 601 and the pixel number 602 of the data to be drawn are detected from the rasterizing direction. When the LFC detects a gradation pattern having a plurality of pixels (603, 604, 605), each color value and the number of pixels are linked in the order of rasterization (606). ). Next, when the creation of the LFC is completed, it is determined 503 whether the gradation shift is not monotonous in the sub-scanning direction and the addition method is not constant. When drawing a gradation, the gradation is different in both the x direction in the main scanning direction and the y direction in the sub scanning direction, and the gradation pattern generated on the first line cannot be diverted. Every time it changes, it is necessary to create a gradation pattern. If the color information is not updated in the sub-scanning direction, the LFC is used as a gradation pattern (504). When the shift in gradation is not monotonous in the vertical direction and conversion in the sub-scanning direction as well as the main scanning direction is necessary, the processing content is changed according to the number of color channel updates (505).

  FIG. 7 shows a state of processing when a conventional diagonal gradation is drawn. The gradation pattern 701 in FIG. 7 is a method of drawing from the position 702 where the same gradation is shifted in the direction of each sub-scan, and each time the start position is changed, the gradation of the region 703 to be actually drawn is expressed diagonally. The drawing area 704 can be drawn obliquely when there is no change in the color value in the sub-scanning direction. Assume that the color difference in the sub-scanning direction of the gradation pattern is Cy1, Cy2, Cy3, and Cy4 for each color channel. When the same color area is not updated in the sub-scanning direction, these four values are Cy1 = 0, Cy2 = 0, Cy3 = 0, and Cy4 = 0, and the same value may be maintained in the sub-scanning direction. However, when color differences such as Cy1 = 1, Cy2 = 4, Cy3 = 1, and Cy4 = 1 are added for each color channel (value other than 0), the color values 1101 of the gradation pattern are different as shown in FIG. The copy means cannot be used (1102). If the color channel needs to be added also in the sub-scanning direction, if up to two threshold values need to be updated, a color difference is added to each color information of the gradation pattern (506). If three or more updates are necessary, a new gradation is generated and processed as before (507). This is because when the gradation of the gradation is updated in the sub-scanning direction, if there are three or more color channels, the amount of calculation when calculating a new gradation pattern is equivalent.

  In updating the LFC, addition processing for the number of pixels is omitted, so when the color difference in the sub-scanning direction is changed, it may be added to the color information regardless of the threshold value. Since the color information is held not by gradation but by a plurality of single-color fills, there is no arithmetic processing for each pixel, and high-speed processing is possible.

  As described above, when the gradation pattern cannot be copied, the update method processing is changed depending on the number of variables to be added to the color channel, whether or not to add color difference information to the first line cache data. To do. Color channel types include RGB, CMYK, etc., and are not dedicated to specific channels.

  Further, in the present invention, drawing using LFC as a gradation pattern generation method eliminates the process of calculating gradation color values for each pixel, thereby enabling high-speed processing. LFC also reduces the cache size by holding the gradation pattern with multiple single-color fill data.

  In a state where a gradation image is attached to the entire background, a method of switching the page orientation is used in order to effectively draw the scanline renderer when drawing. In FIG. 8, the paper orientation of the gradation page whose gradation changes in the horizontal direction in the background of the page is changed to the horizontal orientation 802 for the vertical page 801. Also, the paper orientation is changed to the vertical direction with respect to the horizontal page orientation gradation 803 (804). When the PDL analysis unit 304 generates the DISPLAY LIST 401, the page background image can be rendered as a 1-pixel wide image by rotating the page orientation by 90 degrees (FIG. 10). . When the gradation pattern becomes a gradation 1001 having a width of 1 pixel, enlargement processing 1002 is performed as a single color fill in the main scanning direction. Changing the page orientation eliminates the need to acquire color information for each pixel, improving the processing speed. FIG. 9 is a flowchart of page orientation switching in the PDL analysis unit 304. First, it is detected that gradation (801, 803) exists in the entire page in the main scanning direction to be rasterized (901). Next, a DISPLAY LIST 401 is generated by rotating the page direction by 90 degrees (902). Here, the PDL analysis unit 304 generates a DISPLAY LIST 401 assuming that the gradation background is an enlarged image of 1 pixel width (903). The data rendering unit 305 renders the image having a width of 1 pixel as image data that is enlarged as a whole (904). The page data drawn in the page memory 306 is returned to the original page orientation, and the print control unit 310 prints the page. As a result, when the gradation is applied to the entire background and the color changes on the scan line, the conventional image enlargement process of 1 pixel width can be performed by changing the orientation of the paper, and the processing speed is increased. The effect of can be obtained.

103 Printer Controller 104 Operation Panel 105 Printer Engine

Claims (6)

When drawing a horizontal gradient,
Means (502) for generating a gradation pattern for one line from the gradation start position;
When drawing a gradation with a pattern different from the gradation pattern created above in the sub-scanning direction,
In the above means, when adding the color difference of each color channel in the sub-scanning direction, if the number of pixels of each color different in color difference is within a certain threshold (506), the means for adding the color difference for each pixel of the gradation pattern; ,
In the above means, when the color difference of the color channels is added, if the number of color channels and the number of pixels of each color differ from each other when the color difference is updated with a threshold value or more, a new gradation pattern for one line is drawn (507) )When,
An image forming apparatus (102) comprising: When drawing a horizontal gradation (501), as a method (502) for generating a gradation pattern for one line from the start position of the gradation,
Means for converting the gradation into a plurality of single color fill data;
Means for holding a pixel number (602) and a color value (601) in which the color value of each pixel is equivalent;
Means (606) for generating a structure for linking the information of the filled area in the order of drawing in the main scanning in the means;
Means (504) for copying and drawing the gradation pattern generated by the means for each line;
An image forming apparatus (102) comprising: When the entire print data is a gradation (801, 803) that changes the gradation in the scanning direction,
Means (901) for detecting the gradation;
Means (902) for changing the orientation of the paper using the gradation by 90 degrees;
Means (903) for processing the background as a one pixel wide image (1001) in the main scanning direction by the means;
In the means, means (904) for switching processing (1002) so as to fill in the main scanning direction for each scan line;
Means (905) for returning to the original paper orientation after filling all the pixels by the means;
An image forming apparatus (102) characterized by comprising: When drawing a horizontal gradient,
Means (502) for generating a gradation pattern for one line from the gradation start position;
When drawing a gradation with a pattern different from the gradation pattern created above in the sub-scanning direction,
In the above means, when adding the color difference of each color channel in the sub-scanning direction, if the number of pixels of each color different in color difference is within a certain threshold (506), the means for adding the color difference for each pixel of the gradation pattern; ,
In the above means, when the color difference of the color channels is added, if the number of color channels and the number of pixels of each color differ from each other when the color difference is updated with a threshold value or more, a new gradation pattern for one line is drawn (507) )When,
An image forming method comprising: When drawing a horizontal gradation (501), as a method (502) for generating a gradation pattern for one line from the start position of the gradation,
Means for converting the gradation into a plurality of single color fill data;
Means for holding a pixel number (602) and a color value (601) in which the color value of each pixel is equivalent;
Means (606) for generating a structure for linking the information of the filled area in the order of drawing in the main scanning in the means;
Means (504) for copying and drawing the gradation pattern generated by the means for each line;
An image forming method comprising: When the entire print data is a gradation (801, 803) that changes the gradation in the scanning direction,
Means (901) for detecting the gradation;
Means (902) for changing the orientation of the paper using the gradation by 90 degrees;
Means (903) for processing the background as a one pixel wide image (1001) in the main scanning direction by the means;
In the means, means (904) for switching processing (1002) so as to fill in the main scanning direction for each scan line;
Means (905) for returning to the original paper orientation after filling all the pixels by the means;
An image forming method comprising:

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