JP2006129007A - Print controller, data processing method of print controller, and storage medium having computer readable program stored therein - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To quicken trapping, to enable a user to easily designate a trapping parameter, and to realize trapping of high image quality. <P>SOLUTION: A print controller includes; a determination means for determining an object classification of an inputted drawing command; an object classification information bit map generation means for generating a bit map provided with determined object classification information; and a trapping position determination means which has a means for referring to the object classification information bit map to switch processing and a trapping parameter change means for changing a trapping parameter per object classification. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a color bitmap generation unit that generates a color bitmap from an input drawing command, a unit that generates a color separation for output to a printing apparatus from the generated bitmap, and an edge in the bitmap Edge detecting means for detecting the trap, trapping judging means for judging whether or not trapping should be generated on the edge, trapping color determining means for determining the color of the trapping, and trapping position determining means for determining the position where the determined color is placed. A printing control apparatus comprising:

  Color bitmap generation means for generating a color bitmap from the input drawing command, means for generating a color separation for output to the printing apparatus from the generated bitmap, and an edge for detecting an edge in the bitmap Print control comprising: detection means; trapping determination means for determining whether or not trapping should be generated at an edge; trapping color determination means for determining a color of trapping; and trapping position determination means for determining a position where the determined color is placed. The apparatus employs a trapping technique to correct plate misalignment that occurs when printing a plurality of color separations on the same paper medium.

  FIG. 4 shows an example of misregistration.

  FIG. 4A illustrates a printing result without misregistration in a printing apparatus that performs printing using four colors of Yellow, Magenta, Cyan, and Black. The magenta circle is overwritten on the cyan rectangle, and the cyan rectangle and the magenta circle touch each other.

  FIG. 4B shows the result of misregistration. Here, only magenta is shifted to the right. This results in a blue (magenta + cyan) line to the right of the magenta circle and a paper color (white) line to which no toner is placed on the left.

  A method for correcting misregistration is already known. In general, one of the border plates is expanded to fill the border with the color determined to minimize the visual impact when printed.

  FIG. 5 shows an example of trapping.

  5-1, when the edge of the circle is expanded outward (the color of the circle is expanded outward), this is called spread and wrap.

  In 5-2, when the edge of the circle is reduced inward (rectangular color is enlarged toward the circle), this is called a choke trap. Therefore, when trapping is performed, in an ideal printing press, the contour is a mixed color of upper and lower colors.

  FIG. 6 shows a trapping flowchart.

  In step S601, a color bitmap is generated and input to the trapping means.

  In step S602, an edge in the image is detected. Specifically, the pixel of interest is compared with the pixel on the right of the pixel of interest and the pixel above the pixel of interest for each pixel while scanning the scan line from the upper left to the lower right of the image. If the relationship between the pixel of interest P (Yp, Mp, Cp, Kp) and the comparison pixel Q (Yq, Mq, Cq, Kq) on either the right side or the upper side satisfies the following, it is determined as an edge. Here, Yp is the yellow component of the target pixel P, Mp is the magenta component of the target pixel P, Cp is the cyan component of the target pixel P, and Kp is the black component of the target pixel P.

  If both the target pixel, the right pixel, and the left pixel of the target pixel are determined to be edges, the larger of | (A−B) |

A = Yp + Mp + Cp + Kp
B = Yq + Mq + Cq + Kq
| (A-B) |> M
If it is an edge, the process proceeds to step S603. If it is not an edge, the process returns to step S602 to advance the target pixel to the next pixel and perform edge detection.

  In step S603, it is determined whether or not to perform a trapping process. Here, the following calculation may be used.

  If (A = Yp + Mp + Cp + Kp)> N or (B = Yq + Mq + Cq + Kq)> N, no operation is performed.

  If so, the process proceeds to step S604. If not, the process returns to step S602 to advance the target pixel to the next pixel and perform edge detection.

  In step S604, a replacement color is calculated. For example, the trapping color T (Yt, Mt, Ct, Kt,) is calculated by the following formula.

Yt = Yp + Yq
Mt = Mp + Mq
Ct = Cp + Cq
Kt = Kp + Kq
In step S605, a trapping position is determined. Here, the target pixel may be set as the trapping position.

In step S606, color correction is performed. The target pixel is replaced with the value calculated in step S604. (However, since the values before replacement are used for the upper pixel and the right pixel used when detecting an edge in step S602, it is necessary to hold the value before replacement.)
In step S607, it is determined whether the entire color bitmap has been processed.

  If the entire color bitmap has been processed, the process ends.

If the entire color bitmap has not been processed, the process returns to step S602 to advance the target pixel to the next pixel and perform edge detection.
JP-A-9-247476

  However, a conventional color bitmap generation unit that generates a color bitmap from an input drawing command, a unit that generates a color separation for output to the printing apparatus from the generated bitmap, and an edge in the bitmap Edge detecting means for detecting the trap, trapping judging means for judging whether or not trapping should be generated on the edge, trapping color determining means for determining the color of the trapping, and trapping position determining means for determining the position where the determined color is placed. However, the printing control apparatus having the following problems has the following problems.

  1. At the time of edge detection in step S602, since processing is performed on each pixel of the color bitmap image, there is a problem that processing time is required. This becomes conspicuous when the number of peripheral pixels referred to at the time of edge detection is increased.

  2. In the edge detection in step S602, the trapping determination in step S603, the trapping color determination in step S604, and the trapping position determination in S605, since only the color bitmap image is referred to, parameters suitable for object attributes such as characters, graphics, and images There was a problem that it could not be set.

  3. For the reason “2” above, there has been a problem that high-quality processing suitable for object attributes such as characters, graphics, and images cannot be performed.

  According to a first aspect of the present invention, a color bitmap generation unit that generates a color bitmap from an input drawing command, and a unit that generates a color separation for outputting to the printing apparatus from the generated bitmap. An edge detection means for detecting an edge in the bitmap, a trapping determination means for determining whether or not to generate trapping on the edge, a trapping color determination means for determining the color of the trapping, and a position for placing the determined color In a printing control apparatus comprising a trapping position determination means for determining, a determination means for determining an object type of an input drawing command, an object type information bitmap generation means for generating a bitmap including the determined object type information, Edge detection means, trapping judgment means, trapping color determination hand , The trapping position determining means, is characterized in that it has a means for switching processing by referring to the object type information bitmap, respectively, and a trapping parameter changing means for changing the trapping parameters for each type of object.

  According to a second aspect of the present invention, the color bitmap generation means for generating a color bitmap from the input drawing command is a means for generating a color bitmap in an RGB color space. It is what.

  According to a third aspect of the present invention, the color bitmap generation means for generating a color bitmap from the input drawing command is a means for generating a color bitmap in the YMCK color space. It is what.

  According to a fourth aspect of the present invention, the determination means for determining the object type of the input drawing command is a determination means for determining the object type of a character, graphic, line, or image. Is.

  According to a fifth aspect of the present invention, the determining means for determining the object type from the drawing command and the threshold value is a determining means for determining an object type such as a small character or other characters according to the character point size. It is characterized by being.

  According to a sixth aspect of the present invention, the determination means for determining the object type from the drawing command and the threshold value is a determination means for determining whether the object type is a thin line or other line according to the line width of the line. It is characterized by being.

  A seventh invention according to the present invention is characterized in that the trapping parameter changing means for changing the trapping parameter for each object type specifies whether or not to perform the trapping process.

  According to an eighth aspect of the present invention, the trapping parameter changing means for changing the trapping parameter for each object type is an adjacent color used by the trapping determining means for determining whether or not to generate trapping at the edge. A threshold value for discriminating a color difference between them is designated.

  According to a ninth aspect of the present invention, the trapping parameter changing means for changing the trapping parameter for each object type is replaced with a trapping color by trapping used in the trapping position determining means for determining the position where the determined color is placed. The number of pixels to be specified is specified.

  According to a tenth aspect of the present invention, the trapping parameter changing means for changing the trapping parameter for each object type is replaced with a trapping color by trapping used in the trapping position determining means for determining the position where the determined color is placed. The direction to perform is specified.

  The eleventh aspect of the present invention is characterized in that the trapping parameter changing means for changing the trapping parameter for each type of object designates automatic determination.

  In a twelfth aspect of the present invention, the means for switching processing with reference to the object type information bitmap is used by a trapping position determining means for determining a position where the determined color is to be placed if the object type is a lowercase letter. The direction in which the trapping color is replaced by the trapping is set to a direction in which characters are spread.

  In a thirteenth aspect of the present invention, the means for switching processing with reference to the object type information bitmap is used by a trapping position determining means for determining a position where the determined color is placed if the object type is a thin line. The direction in which the trapping color is replaced by the trapping is the direction in which the fine line is spread.

  In a fourteenth aspect of the present invention, the means for switching processing with reference to the object type information bitmap uses a parameter that does not make the trapping effect conspicuous if the object type is an image. It is what.

  According to a fifteenth aspect of the present invention, the trapping color determining means for determining the trapping color is controlled so as not to exceed a predetermined toner loading amount of the object. is there.

  According to a sixteenth aspect of the present invention, the trapping position determining means for determining the position where the determined color is placed is based on a density difference between adjacent pixels if the adjacent object type of the edge is the same edge. The direction of replacement with the trapping color is determined by trapping.

  According to a seventeenth aspect of the present invention, there is provided a color bitmap generating means for generating a color bitmap from an input drawing command, and means for generating a color separation for outputting to the printing apparatus from the generated bitmap. An edge detection means for detecting an edge in the bitmap, a trapping determination means for determining whether or not to generate trapping on the edge, a trapping color determination means for determining the color of the trapping, and a position for placing the determined color An object for generating a bitmap including a determination means for determining an object type of an input drawing command, and a data processing method for the print control apparatus including a trapping position determination unit for determining and an object type of an input drawing command Type information bitmap generation means, edge detection means, track The tracking determination means, the trapping color determination means, and the trapping position determination means each have means for switching processing with reference to the object type information bitmap, and trapping parameter changing means for changing the trapping parameter for each object type. It is characterized by.

  According to an eighteenth aspect of the present invention, a color bitmap generation unit that generates a color bitmap from an input drawing command, and a unit that generates a color separation for output to the printing apparatus from the generated bitmap. An edge detection means for detecting an edge in the bitmap, a trapping determination means for determining whether or not to generate trapping on the edge, a trapping color determination means for determining the color of the trapping, and a position for placing the determined color An object for generating a bitmap including a determined object type information and a determination means for determining an object type of an input drawing command in a storage medium storing a computer readable program having a trapping position determining unit for determining Type information bitmap generation means and edge detector The trapping determination means, trapping color determination means, and trapping position determination means each have means for switching processing with reference to the object type information bitmap, and trapping parameter change means for changing the trapping parameter for each object type. Is.

  As described above, according to the first invention, the color bitmap generation means for generating a color bitmap from the input drawing command, and the color separation for outputting the generated bitmap to the printing apparatus are provided. Means for generating, edge detecting means for detecting an edge in the bitmap, trapping determining means for determining whether or not trapping should be generated for the edge, trapping color determining means for determining the color of the trapping, and the determined color In a printing control apparatus comprising a trapping position determining means for determining a position for placing an object, a determination means for determining an object type of an input drawing command, and an object type information bitmap for generating a bitmap including the determined object type information Generation means, edge detection means, trapping determination means, trapping The tracking color determination means and the trapping position determination means each have a means for switching processing with reference to the object type information bitmap and a trapping parameter change means for changing the trapping parameter for each object type. The trapping parameter can be realized by the user, and trapping with high image quality can be realized.

  According to the second invention, the color bitmap generation means for generating a color bitmap from the input drawing command is a means for generating a color bitmap in the RGB color space, so that the trapping can be performed at high speed. Can be realized.

  According to the third invention, the color bitmap generation means for generating a color bitmap from the input drawing command is a means for generating a color bitmap in the YMCK color space, so that it can be trapped at high speed. Can be realized.

  According to the fourth aspect of the present invention, the determination means for determining the object type of the input drawing command is a determination means for determining the object type of a character, graphic, line, or image. be able to.

  According to the fifth invention, the determining means for determining the object type from the drawing command and the threshold value is a determining means for determining an object type such as a small character or other characters according to the character point size. , Trapping can be realized at high speed.

  According to the sixth invention, the determination means for determining the object type from the drawing command and the threshold value is a determination means for determining the object type such as a thin line or another line according to the line width of the line. , Trapping can be realized at high speed.

  According to the seventh invention, the trapping parameter changing means for changing the trapping parameter for each object type designates whether or not to perform the trapping process, so that the trapping can be realized at a high speed and the trapping can be realized. Parameters can be easily specified by the user.

  According to the eighth invention, the trapping parameter changing means for changing the trapping parameter for each type of object is a trapping judgment means for judging whether or not trapping should be generated at the edge. Since the threshold value for discriminating the difference in color is specified, it is possible to realize trapping at high speed and the user can easily specify the trapping parameter.

  According to the ninth invention, the trapping parameter changing means for changing the trapping parameter for each object type is a pixel used for trapping color replacement by trapping used in the trapping position determining means for determining the position where the determined color is placed. Since the number is specified, the trapping can be realized at high speed, and the trapping parameter can be easily specified by the user.

  According to the tenth aspect of the invention, the trapping parameter changing means for changing the trapping parameter for each object type is used in the trapping position determining means for determining the position where the determined color is placed, and is the direction in which the trapping color is replaced by trapping. Therefore, trapping can be realized at high speed, and the trapping parameter can be easily specified by the user.

  According to the eleventh aspect of the invention, the trapping parameter changing means for changing the trapping parameter for each object type designates automatic determination, so that the trapping parameter can be realized at high speed and the trapping parameter can be realized. Can be easily specified by the user.

  According to the twelfth invention, the means for switching the processing with reference to the object type information bitmap is the trapping position determining means for determining the position where the determined color is to be placed if the object type is lowercase. Since the direction of replacement with the trapping color is the direction in which characters are spread, the trapping color can be realized at high speed, and the trapping parameter can be easily specified by the user.

  According to the thirteenth aspect, the means for switching the processing with reference to the object type information bitmap is the trapping position determining means for determining the position where the determined color is placed if the object type is a thin line. Since the direction to be replaced with the trapping color is the direction in which the thin line is spread, the trapping color can be realized at a high speed, and the trapping parameter can be easily specified by the user.

  According to the fourteenth aspect of the present invention, the means for switching processing with reference to the object type information bitmap uses parameters that do not make the trapping effect conspicuous if the object type is an image. The trapping parameter can be easily specified by the user.

  According to the fifteenth aspect of the present invention, the trapping color determining means for determining the trapping color is controlled so as not to exceed the predetermined toner loading amount of the object, so that high-quality trapping can be realized. .

  According to the sixteenth aspect of the present invention, the trapping position determining means for determining the position where the determined color is placed is that the trapping position is determined by the density difference between the adjacent pixels if the adjacent object type of the edge is the same edge. Since the direction of replacement with the trapping color is determined by this, trapping can be realized at high speed, and the trapping parameter can be easily specified by the user, and high-quality trapping can be realized.

  According to the seventeenth aspect, a color bitmap generation unit that generates a color bitmap from an input drawing command, a unit that generates a color separation for output to the printing apparatus from the generated bitmap, and a bit Edge detection means for detecting an edge in the map, trapping determination means for determining whether or not to generate trapping on the edge, trapping color determination means for determining the color of the trapping, and trapping for determining the position where the determined color is placed Object type information for generating a bitmap including a determination means for determining an object type of an input drawing command and a data type of the input drawing command in a print control apparatus and a data processing method for the print control apparatus including a position determination unit Bitmap generation means, edge detection means, trapping The disconnecting means, the trapping color determining means, and the trapping position determining means each have means for switching processing with reference to the object type information bitmap, and trapping parameter changing means for changing the trapping parameter for each object type. Trapping can be realized at high speed, the trapping parameter can be easily specified by the user, and high-quality trapping can be realized.

  According to the eighteenth aspect of the invention, a color bitmap generation unit that generates a color bitmap from an input drawing command, a unit that generates a color separation for output to the printing apparatus from the generated bitmap, and a bit Edge detection means for detecting an edge in the map, trapping determination means for determining whether or not to generate trapping on the edge, trapping color determination means for determining the color of the trapping, and trapping for determining the position where the determined color is placed Object type information for generating a bitmap including the determined object type information and a determination unit for determining the object type of the input drawing command in a storage medium storing a computer readable program having position determining means Bitmap generation means, edge detection means, The tapping determination means, the trapping color determination means, and the trapping position determination means each have means for switching processing with reference to the object type information bitmap, and trapping parameter changing means for changing the trapping parameter for each object type. Trapping can be realized at high speed, trapping parameters can be easily specified by the user, and high-quality trapping can be realized.

Example 1
Hereinafter, the present invention is applied to a laser beam printer (hereinafter abbreviated as LBP) and will be described in more detail with reference to the drawings.

  Before describing the configuration of the present embodiment, the configuration of the LBP to which the present embodiment is applied will be described with reference to FIGS.

  FIG. 1 is a cross-sectional view showing the internal structure of the LBP of the embodiment.

  FIG. 2 is a block diagram illustrating a control configuration of the main body shown in FIG.

  In the figure, reference numeral 100 denotes an LBP main body, and corresponding character patterns according to a character print command, various graphic drawing commands, an image drawing command, a color designation command, etc. supplied from a host computer (201 in FIG. 2) connected to the outside. An image is formed on a recording sheet that is a recording medium.

  Reference numeral 151 denotes an operation panel on which a switch for operation and an LED display or an LCD display for displaying the status of the printer are arranged.

  A printer control unit 101 controls the entire LBP 100 and analyzes a character printing command supplied from a host computer.

  The LBP in this embodiment converts RGB color information into M (magenta) C (cyan) Y (yellow) K (black), and forms and develops them in parallel. Has a development mechanism. The printer control unit 101 generates a print image for each MCYK, converts it into a video signal, and outputs it to each MCYK laser driver.

  The M (magenta) laser driver 110 is a circuit for driving the semiconductor laser 111, and switches on and off the laser beam 112 emitted from the semiconductor laser 111 in accordance with an input video signal. The laser beam 112 is swung in the left-right direction by the rotary polygon mirror 113 to scan the electrostatic drum 114. As a result, an electrostatic latent image of a character or figure pattern is formed on the electrostatic drum 114. The latent image is developed by a developing unit (toner cartridge) 115 around the electrostatic drum 114 and then transferred to a recording sheet.

  C (cyan), Y (yellow), and K (black) have the same image formation / development mechanism as M (magenta), and 120, 121, 122, 123, 124, and 125 are C (cyan) images. Formation / development mechanism, 130, 131, 132, 133, 134, 135 are Y (yellow) image formation / development mechanisms, 140, 141, 142, 143, 144, 145 are K (black) image formation / development mechanisms. Development mechanism. The individual functions are the same as those of the M (magenta) image forming / developing mechanism, and a description thereof will be omitted.

  A cut sheet is used as the recording paper, and the cut sheet recording paper is stored in a paper feed cassette 102 mounted on the LBP and is kept at a certain height by a spring 103. A paper feed roller 104 and transport rollers 105 and 106 are used. Are taken into the apparatus, are placed on the sheet conveying belt 107, and pass through each image forming / developing mechanism of MCYK.

  Each MCYK toner (powder ink) transferred to the recording paper is fixed to the recording paper by heat and pressure by the fixing unit 108, and the recording paper is output to the upper part of the LBP main body by the conveying rollers 109 and 150.

  FIG. 2 is a block diagram showing a schematic configuration of the LBP control system 101 shown in FIG.

  This LBP control system inputs data 218 consisting of characters, graphics, image drawing commands and color information sent from the host computer 201, which is the source of print information, and provides document information and the like in units of pages. To print.

  An input / output interface unit 202 exchanges various types of information with the host computer 201, and an input buffer 203 temporarily stores various types of information input via the input / output interface unit 202.

  Reference numeral 204 denotes a character pattern generator, which includes a font information part 222 storing attributes such as character width and height, and the address of the actual character pattern, a character pattern part 223 storing the character pattern itself, and a reading thereof. However, it consists of a control program.

  The reading control program is included in the ROM 219, and has a code conversion function for calculating the address of the character pattern corresponding to the character code when the character code is input.

  Reference numeral 205 denotes a RAM which has a font cache area 207 for storing character patterns output from the character pattern generator 204, and a storage area 206 for storing external character fonts and form information sent from the host computer 201 and the current printing environment. Contains.

  In this way, by storing the pattern information once developed into a character pattern in the font cache area 207 as a font cache, it is not necessary to decode the same character again and develop the pattern when printing the same character. Deployment to patterns is faster.

  Reference numeral 208 denotes a CPU for controlling the entire control system of the printer, and the entire apparatus is controlled by a control program of the CPU 208 stored in the ROM 219.

  An intermediate buffer 209 stores an internal data group generated based on the input data 218.

  After reception of data for one page is completed, the data is converted into simpler intermediate data and stored in the intermediate buffer, then rendered by the renderer 210 in units of several lines, and output to the band buffer 211 as a print image. .

  The renderer 210 generates a rendering bitmap image of RGB for each color of 8 bits / pixel in units of several lines. At the same time, when R = G = B, 3 bits / pixel indicating whether each pixel is a character, graphic, or image. It is possible to generate an object type information image of a total of 4 bits / pixel including 1 bit / pixel indicating whether to print with only K or YMCK mixed colors.

  The band buffer 211 can store at least eight lines of RGB drawing bitmap images and object type information images. At this time, the drawing bitmap image and the object type information image are compressed separately.

  The image output to the band buffer 211 is compressed in units of several scan lines by the compression unit 212 and stored in the page memory 213.

  After rendering of the intermediate buffer memory for one page is completed and stored in the page memory 213, the decompression unit 214 reads and decompresses it in units of several lines. At this time, the drawing bitmap image and the object type information image are read out separately and decompressed.

  Next, the decompressed data is converted by the color conversion unit 215 from a bitmap image of 8 bits / pixel for each color of RGB to a bitmap image of 4 bits / pixel for each color of YMCK. More specifically, a bitmap image of 8 bits / pixel for each RGB color is converted to 10 bits / pixel for each color of YMCK, and a bitmap image of 10 bits / pixel for each YMCK color is converted to 10 bits / pixel for each YMCK color using gamma correction. Then, the YMCK color 10 bits / pixel bitmap image is converted to YMCK color 4 bits / pixel using halftoning processing. At this time, when color-converting each pixel of the drawing bitmap image, the color conversion method is switched depending on the type of the corresponding object type information pixel.

  Specifically, first, 8 bits / pixel of each RGB color is converted to 10 bits / pixel of each YMCK color using information of 1 bit / pixel indicating whether printing is performed only with K or mixed color of YMCK. Next, 10 bits / pixel of each color of YMCK is converted into 4 bits / pixel of YMCK using information of 3 bits / pixel indicating whether each pixel is a character, a graphic, or an image.

  Next, it is converted into a video signal by the output interface unit 216 and output to the printer printing unit 217.

  Reference numeral 217 denotes a print mechanism portion of a page printer that prints image information based on a video signal from the output interface unit 216.

  As described above with reference to FIG. 2, in the LBP according to the present embodiment, MCYK image formation / development is performed in parallel. Therefore, the output interface unit 216 includes an M output interface unit, a C output interface unit, a Y output interface unit, K Each of the four interface units of the output interface unit independently acquires dot data from the color conversion unit 215, converts it into a video signal, and outputs it to the laser drivers 110, 120, 130, 140 of each plane.

  Reference numeral 220 denotes a non-volatile memory composed of a general EEPROM or the like, and is hereinafter referred to as NVRAM (Non Volatile RAM). The NVRAM 220 stores panel setting values designated on the operation panel 151 and the like.

  Data 221 is transmitted from the LBP to the host computer 201.

  The ROM 215 is used for analysis of data input from the host computer 201, generation of intermediate data, control program for the printing mechanism main body 213, and color conversion from 8 bits / pixel for each YMCK color to 4 bits / pixel for each YMCK color. A table to be used is also included.

  In this embodiment, a color laser printer is described as an example of a printing apparatus. However, a color printer such as a color inkjet printer or a color thermal transfer printer may be used.

  Although the renderer 210 generates a rendering bitmap image of 8 bits / pixel for each color of RGB, the renderer 210 may generate a rendering bitmap image of 8 bits / pixel for each color of YMCK in units of several lines. The renderer 210 may generate a rendering bitmap image of gray 8 bits / pixel in units of several lines.

  Further, the bit / pixel of each color may be any value.

  In this case, the band buffer 211, the compression unit 212, the page memory 213, and the decompression unit 214 only need to correspond to the color space and bits / pixel generated by the renderer 210.

  Furthermore, the decompressed data may be any data that the color converter 215 converts the data generated by the renderer 210 into a color space and bits / pixel corresponding to the output interface 216.

  When the renderer 210 generates a rendering bitmap image of gray 8 bits / pixel, the compression unit 212 and the expansion unit 214 compress and expand gray 8 bits / pixel data, and the color conversion unit 215 performs gray 8 bits. / Pixel data is converted to K4 bit / pixel data.

  FIG. 3A shows intermediate data stored in the intermediate buffer 209.

  FIG. 3B shows a drawing bitmap image generated by the renderer 210.

  FIG. 3C shows an object type information image generated by the renderer 210.

  FIG. 3-4 illustrates a second bitmap image generated by the color conversion unit 215.

First. It is determined whether the input command is a character command, a graphic command, an image command, whether to print with only K or mixed color of YMCK, and each intermediate data stored in the intermediate buffer 209 has a flag. (Figure 3-1)
Specifically, the object 1 includes an attribute: a character, a color attribute: K, a print position (X, Y), a font, a size, a character code, a color, and a drawing logic, and an object 2 includes an attribute: a figure, a color attribute: K , Printing position (X, Y), shape (circle), radius, color, drawing logic, and as object 3, attribute: image, color attribute: YMCK, printing position (X, Y), image width, height, Provides pointers to image entities and drawing logic.

  Here, the drawing logic of all objects is S (overwrite) designation.

  Thus, the intermediate data includes information on the shape, color, and print position of each drawing object.

  When the intermediate data is drawn by the renderer 210, an object type information image (FIG. 3-3) is obtained together with a drawing bitmap image (FIG. 3-2).

  Here, the drawing bitmap image (FIG. 3-2) is obtained by drawing the intermediate data at 8 bits / pixel for each color of RGB. A portion where nothing is drawn is represented by white RGB = (0xff, 0xff, 0xff).

  Here, the object type information image (FIG. 3-3) is drawn at 4 bits / pixel using the intermediate data attribute and color attribute.

  Specifically, the contents of 4 bits / pixel are as follows.

Bit 0: 1 if the color attribute is K, 0 if YMCK
Bit 1: 1 if attribute is image, 0 if other
Bit 2: 1 if attribute is graphic, 0 if other
Bit 3: 1 if attribute is character, 0 if other
Therefore, the example character area is drawn as 0x9, the graphic area is drawn as 0x5, and the image area is drawn as 0x2. The part where nothing is drawn is represented by 0x0.

  In addition, the rendering unit 112 obtains a second bitmap having attributes corresponding to each pixel of the printing result (FIG. 3-4).

  Here, when the second bitmap image of FIG. 3-4 is generated from the drawing bitmap image of FIG. 3-2, the processing parameter is changed according to the attribute result of FIG. 3-3.

  Specifically, first, using bit 0 of the object type information image (1 bit / pixel information indicating whether printing is performed only with K or mixed color of YMCK), RGB colors 8 bits / pixel are converted into YMCK colors. Convert to 10 bits / pixel.

  Here, the pixel of the drawing bitmap image corresponding to the pixel whose bit 0 of the object type information image is K is RGB using a Look Up Table that guarantees Y = M = C = 0 when R = G = B. To YMCK.

  The pixel of the drawing bitmap image corresponding to the pixel whose bit 0 of the object type information image is YMCK is changed from RGB to YMCK using a Look Up Table that does not guarantee Y = M = C = 0 when R = G = B. Converted.

  Next, 10 bits / pixel of each color of YMCK is converted to 4 bits / pixel of YMCK using bits 1 to 3 of the object type information image (3 bits / pixel information indicating whether each pixel is a character, graphic, or image). .

  Here, the pixel of the drawing bitmap image corresponding to the pixel whose bit 1 of the object type information image is 1 converts YMCK 10 bits / pixel into YMCK 4 bits / pixel using an image halftone parameter.

  A pixel of the drawing bitmap image corresponding to a pixel whose bit 2 of the object type information image is 1 converts YMCK 10 bits / pixel into YMCK 4 bits / pixel using a halftone parameter for graphics.

  The pixel of the drawing bitmap image corresponding to the pixel whose bit 3 of the object type information image is 1 converts YMCK 10 bits / pixel into YMCK 4 bits / pixel using the halftone parameter for characters.

  In this way, the second bitmap image can be generated using the color conversion parameter and the halftone parameter that are optimal for each region.

  When the renderer 210 generates a rendering bitmap image of gray 8 bits / pixel, bit 0 of the object type information image is ignored and converted from gray 8 bits / pixel to K10 bits / pixel.

  Further, 10 bits / pixel of each K color is converted into K4 bits / pixel using bits 1 to 3 (information of 3 bits / pixel indicating whether each pixel is a character, a graphic, or an image) of the object type information image.

  FIG. 7 shows a user interface for setting various parameters for each type of object.

  The following settings are possible for each character, figure, and image.

  Whether to trap or not, or automatically.

  Whether to increase the detection rate for trapping color judgment, moderate, lower, or automatically.

  Whether the trapping width is wide, medium, thin, or automatic.

  Whether to spread, choke, or automatically as the trapping direction.

  Gray compensation: Yes (guaranteed to print only with K when RGB colors are equivalent), or not (do not guarantee to print only with K when RGB colors are equivalent), or automatically Or?

  Whether the total amount of toner applied to YMCK is increased, decreased, or automatically.

  FIG. 8 shows a flowchart of this embodiment.

  In step S801, the color bitmap decompressed by the decompression unit 214, the object type information bitmap, and the object-specific processing parameters are input to the trapping means. Here, the object-specific processing parameter means information input from the operation panel 151 attached to the host computer or the printing apparatus by various settings by the user interface shown in FIG.

  In step S802, an edge in the image is detected. Specifically, the following processing is performed on the target pixel for each pixel while scanning the scan line from the upper left to the lower right of the image.

  1. The object type information bitmap is searched, and it is determined whether or not the pixel is set to be trapped in the object-specific processing parameters.

  2. If the pixel does not need to be trapped, it is determined as a non-edge and this step is terminated.

  3. If the pixel is to be trapped, the object type information bitmap is referred to, and for each pixel, the pixel of interest is compared with the pixel to the right of the pixel of interest, above the pixel of interest, and to the left of the pixel of interest.

4. If the value of the object type information bitmap is different, it is determined as an edge and this step is terminated. 5. If the value of the object type information bitmap is the same, the following processing is performed on the color bitmap. Do.

  For each pixel, the pixel of interest is compared with the pixel to the right of the pixel of interest, above the pixel of interest, and to the left of the pixel of interest. If the relationship between the pixel of interest P (Yp, Mp, Cp, Kp) and the comparison pixel Q (Yq, Mq, Cq, Kq) on either the right, top, or left side satisfies the following, it is determined as an edge. Here, Yp is the yellow component of the target pixel P, Mp is the magenta component of the target pixel P, Cp is the cyan component of the target pixel P, and Kp is the black component of the target pixel P. Here, the YMCK 10-bit value converted by the color conversion unit 215 is used as the pixel value.

  If both the target pixel, the right pixel, and the left pixel of the target pixel are determined to be edges, the larger of | (A−B) |

A = Yp + Mp + Cp + Kp
B = Yq + Mq + Cq + Kq
| (A-B) |> M
If it is an edge, the process proceeds to step S803. If it is not an edge, the process returns to step S802 to advance the target pixel to the next pixel and perform edge detection.

  Here, the value of M is variable depending on the object type of the target pixel and the trapping detection rate parameter of the processing parameter for each object.

  In step S803, it is determined whether or not to perform trapping processing. The determination method is performed according to the following procedure.

  1. Referring to the object type information bitmap, it is determined whether the pixel of interest or the pixel of the reference pixel is an area (0x0) where nothing is drawn.

  2. If the area is not drawn (0x0), it is determined that trapping is not necessary, and this step is terminated.

  3. If it is not a non-drawn area (0x0), it is determined whether or not to perform trapping according to the following equation.

  If (A = Yp + Mp + Cp + Kp)> N or (B = Yq + Mq + Cq + Kq)> N, no operation is performed.

  If so, the process proceeds to step S804. If not, the process returns to step S802 to advance the target pixel to the next pixel and perform edge detection.

  Here, the value of N is variable depending on the object type of the target pixel and the trapping detection rate parameter of the processing parameter for each object.

  In step S804, a replacement color is calculated. For example, the trapping color T (Yt, Mt, Ct, Kt,) is calculated by the following formula.

Yt = Yp + Yq
Mt = Mp + Mq
Ct = Cp + Cq
Kt = Kp + Kq
In step S805, the trapping position is determined. Here, the target pixel may be set as the trapping position.

In step S806, color correction is performed. The target pixel is replaced with the value calculated in step S604. (However, since the value before replacement is used for the upper pixel and the right pixel used when detecting an edge in step S802, it is necessary to hold the value before replacement.)
In step S807, it is determined whether the entire color bitmap has been processed.

  If the entire color bitmap has been processed, the process ends.

  If the entire color bitmap has not been processed, the process returns to step S802 to advance the target pixel to the next pixel and perform edge detection.

  As described above, by using the object type information bitmap and the processing parameters for each object for trapping, the trapping can be realized at high speed, and the user can easily specify the trapping parameters, and the image quality is high. Trapping can be realized.

(Example 2)
In the first embodiment, the attribute of the object type information image (FIG. 3-3) is as follows.
Bit 0: 1 if the color attribute is K, 0 if YMCK
Bit 1: 1 if attribute is image, 0 if other
Bit 2: 1 if attribute is graphic, 0 if other
Bit 3: 1 if attribute is character, 0 if other
A line may be added to bit 4.

  A thin line may be added to bit 5.

  Further, a lowercase letter may be added to bit 6.

  As described above, by using the object type information bitmap and the object-specific processing parameters for trapping, the trapping process according to the object type can be performed.

(Example 3)
In the first embodiment, when the trapping position is determined in step S805, only the target pixel is set as the trapping position, and the trapping pixel width is set to 1. The pixel width may be determined based on the original. For example, it may be 3 pixels if the width setting is thick, 2 pixels if it is medium, or 1 pixel if it is thin.

  As described above, the trapping process with higher image quality can be performed by using the object type information bitmap and the object-specific processing parameters for trapping.

Example 4
In the first embodiment, when the trapping position is determined in step S805, only the target pixel is set as the trapping position, and the trapping pixel width is set to 1. Therefore, the trapping direction is irrelevant. The trapping method may be determined based on the trapping direction parameter of the processing parameter.

  In this case, the following rules may be followed.

  1. If the edge is an edge adjacent to the same object attribute, the spread is made in the darker one.

  2. If the edge is an edge adjacent to a different object attribute and the trapping direction parameter differs between different objects, the direction is determined according to the direction designation.

  3. The edge is an edge adjacent to different object attributes, and if the trapping direction parameter is the same between different objects, the edge is spread to the darker side if different.

  As described above, the trapping process with higher image quality can be performed by using the object type information bitmap and the object-specific processing parameters for trapping.

(Example 5)
In the first embodiment, when various trapping designations of the image object are set to automatic in FIG. 7, the following behavior may be performed so that the trapping effect is small.

  No image trapping.

  When image trapping is to be performed, the detection rate of the trapping color determination is lowered.

  When image trapping starts, the trapping width is narrowed.

  As described above, the trapping process with higher image quality can be performed by using the object type information bitmap and the object-specific processing parameters for trapping.

(Example 6)
In the first embodiment, even when the fine line is not designated in FIG. 7, the thin line may be specially processed. Specifically, the thin line trapping direction is always a spread. This is to prevent the thin line from being replaced with another color when the choke process is performed, so that the original color is not retained.

(Example 7)
In the first embodiment, even when there is no designation of lowercase letters in FIG. 7, special processing may be performed for lowercase letters. Specifically, the lowercase trapping direction is always spread. This is in order to prevent the lower case character from being replaced with another color and the original color not being retained when the choke process is performed.

(Example 8)
In step S804, the color to be replaced is calculated as follows. However, an object type information bitmap, and an application amount control parameter such as an object-specific processing parameter may be used.

Yt = Yp + Yq
Mt = Mp + Mq
Ct = Cp + Cq
Kt = Kp + Kq
FIG. 9 shows a conversion method for the applied amount control.

  FIG. 14 shows a parameter B conversion method for converting YMCK (Y, M, C, K) into YMCK (Y ′, M ′, C ′, K ′). Here, the input / output of YMCK is 8 bits for each color.

  In step S901, the YMCK values are summed and compared with a threshold value N.

  If larger than N, the process proceeds to S902.

  If smaller than N, the process proceeds to S906.

  In S902, the minimum value of YMC is set as the UCR value using the following equation.

UCR = min (Y, M, C)
In S903, the Under Color Removal process is performed using the UCR value calculated in S902 using the following equation.

K '= min (255, K + UCR)
Y = Y− (K′−K)
M = M− (K′−K)
C = C- (K'-K)
K = K '
In step S904, the YMCK values are summed and compared with the threshold value N. Here, N can be changed according to the amount control value of the object-specific processing parameter.

  If it is larger than N, the process proceeds to S905.

  If smaller than N, the process proceeds to S906.

  In step S905, the YMC value is reduced at the same rate using the following equation.

Y '= Yx (NK) / (Y + M + C)
M ′ = M x (N−K) / (Y + M + C)
C ′ = C x (NK) / (Y + M + C)
Y = Y ′; M = M ′; C = C ′;
In S906, the calculated (Y, M, C, K) is substituted for YMCK (Y ′, M ′, C ′, K ′).

  As described above, the trapping process with higher image quality can be performed by using the object type information bitmap and the object-specific processing parameters for trapping.

Example 9
In the first embodiment, trapping edge detection, trapping determination, trapping color determination, and color correction are performed in the YMCK color space. However, an RGB color space may be used.

  In the case of the RGB color space, in step 802, if the values of the object type information bitmap are the same, the following processing is performed on the color bitmap.

  For each pixel, the pixel of interest is compared with the pixel to the right of the pixel of interest, above the pixel of interest, and to the left of the pixel of interest. If the relationship between the pixel of interest P (Rp, Gp, Bp) and the comparison pixel Q (Rq, Gq, Bq) on either the right side, the upper side, or the left side satisfies the following, it is determined as an edge.

Lp = Func (Rp, Gp, Bp)
Lq = Func (Rq, Gq, Bq)
| (Lp, Lq) |> M
Func is a conversion formula to CIELV.

  If it is an edge, the process proceeds to step S803. If it is not an edge, the process returns to step S802 to advance the target pixel to the next pixel and perform edge detection.

  Here, the value of M is variable depending on the object type of the target pixel and the trapping detection rate parameter of the processing parameter for each object.

  In step 803, if the area is not drawn (0x0), RGB is converted into CIE LUV. If the distance in the UV space is greater than N, the process proceeds to step S804. If it is not larger, the process returns to step S802 to advance the target pixel to the next pixel and perform edge detection.

  Here, the value of N is variable depending on the object type of the target pixel and the trapping detection rate parameter of the processing parameter for each object.

  In step S804, a replacement color is calculated. For example, the trapping color T (Rt, Gt, Bt) is calculated by the following formula.

Rt = (Rp + Rq) / 2
Gt = (Gp + Gq) / 2
Bt = (Bp + Bq) / 2
In step S806, color correction is performed. The target pixel is replaced with the value calculated in step S604. (However, since the value before replacement is used for the upper pixel and the right pixel used when detecting an edge in step S802, it is necessary to hold the value before replacement.)
At this time, the object type information bitmap corresponding to the pixel whose color is to be replaced is also replaced by the object attribute to be spread.

  As described above, by using the object type information bitmap and the processing parameters for each object for trapping, the trapping can be realized at high speed, and the user can easily specify the trapping parameters, and the image quality is high. Trapping can be realized.

FIG. 1 is a cross-sectional view showing the internal structure of the LBP of the embodiment. FIG. 2 is a block diagram illustrating a control configuration of the main body shown in FIG. FIG. 3A shows intermediate data stored in the intermediate buffer 209. FIG. 3B shows a drawing bitmap image generated by the renderer 210. FIG. 3C shows an object type information image generated by the renderer 210. FIG. 3-4 illustrates a second bitmap image generated by the color conversion unit 215. FIG. 4 shows an example of misregistration. FIG. 5 shows an example of trapping. FIG. 6 shows a trapping flowchart. FIG. 7 shows a user interface for setting various parameters for each type of object. FIG. 8 shows a flowchart of this embodiment. FIG. 9 shows a conversion method for the applied amount control.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Printer body 101 Printer control unit 102 Paper feed cassette 103 Spring for lifting paper 104 Paper feed roller 105 Paper transport roller 106 Paper transport roller 107 Paper transport belt 108 Fixing device 109 Paper transport roller 110 Laser driver (for magenta)
111 Semiconductor laser emitting device (for magenta)
112 Laser beam (for magenta)
113 Rotating polygon mirror (for magenta)
114 Electrostatic drum (for magenta)
115 Toner cartridge (for magenta)
120 Laser driver (for cyan)
121 Semiconductor laser emitting device (for cyan)
122 Laser beam (for cyan)
123 Rotating polygon mirror (for cyan)
124 Electrostatic drum (for cyan)
125 toner cartridge (for cyan)
130 Laser driver (for yellow)
131 Semiconductor laser emitting device (for yellow)
132 Laser beam (for yellow)
133 Rotating polygon mirror (for yellow)
134 Electrostatic drum (for yellow)
135 Toner cartridge (for yellow)
140 Laser driver (for black)
141 Semiconductor laser emitting device (for black)
142 Laser beam (for black)
143 Rotating polygon mirror (for black)
144 Electrostatic drum (for black)
145 Toner cartridge (for black)
150 Paper Conveying Roller 151 Operation Panel 201 Host Computer 202 Input / Output Interface Unit with Host Computer 203 Input Buffer 204 Character Pattern Generator 205 RAM
206 Storage area for storing various registration data, printing environment, etc. 207 Font cache area 208 CPU
209 Storage area for storing print data 210 Renderer 211 Band buffer for generating final output image 212 Compression unit 213 Page memory 214 Expansion unit 215 Color conversion unit 216 Output interface unit to printing mechanism unit 217 Printing mechanism unit 218 Input data from the host computer 219 ROM
220 NVRAM
221 Data transmitted from LBP to host computer 222 Font information part 223 Character pattern part

Claims (18)

Color bitmap generation means for generating a color bitmap from the input drawing command;
Means for generating a color separation for output to the printing apparatus from the generated bitmap;
Edge detection means for detecting edges in the bitmap;
Trapping determination means for determining whether or not trapping should be generated at an edge;
Trapping color determination means for determining the color of the trapping;
A printing control apparatus comprising: a trapping position determining means for determining a position where the determined color is placed;
Determining means for determining the object type of the input drawing command;
Object type information bitmap generating means for generating a bitmap comprising the determined object type information;
The edge detection means, trapping determination means, trapping color determination means, and trapping position determination means each have means for switching processing with reference to the object type information bitmap,
And a trapping parameter changing means for changing the trapping parameter for each type of object. The color bitmap generation means for generating a color bitmap from the input drawing command is:
The printing control apparatus according to claim 1, wherein the printing control apparatus is a unit that generates a color bitmap of an RGB color space. The color bitmap generation means for generating a color bitmap from the input drawing command is:
The print control apparatus according to claim 1, wherein the print control apparatus is a unit that generates a color bitmap of a YMCK color space. The determination means for determining the object type of the input drawing command is:
The print control apparatus according to claim 1, wherein the print control apparatus is a determination unit that determines an object type of a character, a figure, a line, and an image. The determination means for determining the object type from the drawing command and the threshold is:
The print control apparatus according to claim 1, wherein the print control apparatus is a determination unit that determines an object type such as a small character or another character according to a character point size. The determination means for determining the object type from the drawing command and the threshold is:
The print control apparatus according to claim 1, wherein the print control apparatus is a determination unit that determines an object type such as a thin line or another line according to a line width. The trapping parameter changing means for changing the trapping parameter for each object type is as follows:
The print control apparatus according to claim 1, wherein trapping processing is specified. The trapping parameter changing means for changing the trapping parameter for each object type is as follows:
The printing control apparatus according to claim 1, wherein a threshold value for determining a difference in color between adjacent colors is used, which is used by a trapping determination unit that determines whether or not trapping should be generated at an edge. The trapping parameter changing means for changing the trapping parameter for each object type is as follows:
2. The print control apparatus according to claim 1, wherein the number of pixels to be replaced with the trapping color by the trapping is specified, which is used in the trapping position determining means for determining the position where the determined color is placed. The trapping parameter changing means for changing the trapping parameter for each object type is as follows:
The printing control apparatus according to claim 1, wherein a direction for replacing the trapped color by trapping is specified, which is used by a trapping position determining unit that determines a position where the determined color is placed. The trapping parameter changing means for changing the trapping parameter for each object type is as follows:
The print control apparatus according to claim 1, wherein automatic printing is designated. The means for switching processing with reference to the object type information bitmap is as follows:
12. The printing according to claim 11, wherein if the object type is a lowercase letter, the direction of replacing the trapping color by the trapping used in the trapping position determining means for determining the position where the determined color is placed is the direction of spreading the characters. Control device. The means for switching processing with reference to the object type information bitmap is as follows:
12. The printing according to claim 11, wherein if the object type is a fine line, the direction for replacing the trapped color by the trapping used in the trapping position determining means for determining the position where the determined color is placed is the direction in which the fine line is spread. Control device. The means for switching processing with reference to the object type information bitmap is as follows:
12. The print control apparatus according to claim 11, wherein if the object type is an image, a parameter that does not make a trapping effect conspicuous is used. The trapping color determining means for determining the trapping color is as follows.
The print control apparatus according to claim 1, wherein control is performed so as not to exceed a predetermined toner loading amount of the object. The trapping position determining means for determining the position to place the determined color is
The printing control apparatus according to claim 1, wherein if the adjacent object type of the edge is the same edge, the direction of replacement with the trapping color is determined by trapping based on the density difference with the adjacent pixel. Color bitmap generation means for generating a color bitmap from the input drawing command;
Means for generating a color separation for output to the printing apparatus from the generated bitmap;
Edge detection means for detecting edges in the bitmap;
Trapping determination means for determining whether or not trapping should be generated at an edge;
Trapping color determination means for determining the color of the trapping;
In a printing control apparatus and a data processing method for a printing control apparatus, comprising: a trapping position determination unit that determines a position where the determined color is placed;
Determining means for determining the object type of the input drawing command;
Object type information bitmap generating means for generating a bitmap comprising the determined object type information;
The edge detection unit, the trapping determination unit, the trapping color determination unit, and the trapping position determination unit each include a unit that switches processing with reference to the object type information bitmap.
And a trapping parameter changing means for changing a trapping parameter for each type of object. Color bitmap generation means for generating a color bitmap from the input drawing command;
Means for generating a color separation for output to the printing apparatus from the generated bitmap;
Edge detection means for detecting edges in the bitmap;
Trapping determination means for determining whether or not trapping should be generated at an edge;
Trapping color determination means for determining the color of the trapping;
A storage medium storing a computer-readable program comprising: a trapping position determining means for determining a position where the determined color is placed;
Determining means for determining the object type of the input drawing command;
Object type information bitmap generating means for generating a bitmap comprising the determined object type information;
The edge detection means, trapping determination means, trapping color determination means, and trapping position determination means each have means for switching processing with reference to the object type information bitmap,
A storage medium storing a computer-readable program having trapping parameter changing means for changing a trapping parameter for each object type.

Images