JPH06218989A - Image processor - Google Patents

Abstract

PURPOSE:To provide an image processor in which a plane of color component data except black is effectively used for developing black component data. CONSTITUTION:PDL data sent from a host computer 12 is developed to raster image data by a CPU 1, CMYK are respectively formed of planes of 400dpi, 1 bit/pixel in a full-color mode, four planes are gathered to one in a black mode, and written in an image memory 7C of a full page to become an image memory for a k component of 400dpi, 4 bits/pixel. An LUT 16 multi-values any of four color component data read from an image memory 7 to 8 bits in response to the color component formed by an image forming unit 8 in the full-color mode and multi-values K component data of 4 bits read from the memory 7 to 8 bits in the black mode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus, for example, an image processing apparatus for processing data described in a page description language (hereinafter referred to as "PDL") and outputting it as image data.

[0002]

2. Description of the Related Art FIG. 10 is a block diagram showing the configuration of a printer of Conventional Example 1. The printer shown in the figure forms an image represented by PDL (Page Description Language) data received from the outside, and as shown in the figure, is sent from a host computer 112 via an interface 111 and an external interface 106. PDL data is
Once stored in the PDL buffer 113, the CPU 10
1 is expanded into raster image data and written in the full page image memory 107. The ROM 102
Holds a program executed by the CPU 101, and a RAM
Reference numeral 103 denotes a work memory of the CPU 101, a font ROM 104 holds information for developing a character code included in PDL data into a bit image, and a dither pattern ROM 105 uses a dither method which is one of binarization methods. Holds the dither pattern when used. The RAM and ROM and the CPU 101 are the CPU bus 110.
Tied together.

The image memory 107 is a memory for holding raster image data, and for each of the four color components (cyan C, magenta M, yellow Y, black K), planes 107c, 107m, 1 bit / pixel of 107 bits, respectively. 107
y, 107k. That is, since the raster image data is stored in the image memory 107 as binary data for each color component, the multi-valued data included in the input PDL data is subjected to area gradation by the binarization method such as the dither method described above. Then, the data is written in the image memory 107.

On the other hand, the image forming unit 108 is a color printer engine which forms an image in sequence with respect to a plurality of output color components (C, M, Y, K), and each output color component is stored in the image memory 107. The planes correspond to each other, and image formation is performed based on the image signal 153 read from the image memory 107 and processed. The address generator 109 generates a read address signal 152 for the image memory 107 based on the synchronization signal 151 from the image forming unit 108.
The selector 114 selects any one of the four color component data read from the image memory 107 according to which color component image the image forming unit 108 forms. The binary multi-value converter 115 multi-values the binary color component data output from the selector 114 for passing to the image forming unit 108. This multi-value conversion is "0" when the input is "0".
When the input is "1", "FF" should be output.

Generally, the printing speed of an electrophotographic printer is high, and reading from the image memory 107 needs to be remarkably high as compared with writing to the image memory 107. Further, generally, in an electrophotographic printer, it is not possible to stop halfway until one print is completed, so raster image data for one page needs to be expanded in the image memory.

FIG. 11 is a block diagram showing the structure of the printer of the second conventional example. In addition, in the conventional example 2 shown in FIG. 11, about the same structure as the conventional example 1 shown in FIG. 10, the same code | symbol is attached | subjected and the detailed description is abbreviate | omitted. Figure 1
1, the image forming unit 120 is an electrophotographic black and white binary printer, and forms an image based on the image signal read from the full page image memory 119.

[0007]

However, the above-mentioned conventional example 1
However, there were the following problems. Color PDL
In addition to the full-color mode in which all color components are used, the printer is generally provided with a black mode in which only black components are used in order to obtain the same output as in a black-and-white printer. In this black mode, the plane for developing the black component data is the same as in the full color mode, and the planes for other color components are not used at all, or are used only for the purpose of developing the next page. It was

Needless to say, the higher the number of planes of each color component is, the higher the quality of image output can be obtained, and it has been desired to increase the number of planes as much as possible within the limited memory capacity. Further, in the above-mentioned conventional example 2,
There were the following problems. The above-mentioned Conventional Example 2 is for a monochrome binary printer, but when this is applied to a full-color printer, there arises a problem that the number of bits of each pixel increases. Assuming that the full-color printer has four color components and that each pixel corresponding to the resolution of the image forming unit 120 on a one-to-one basis has 8 bits, it is 32 bits compared to a monochrome binary printer having the same resolution. It requires double the image memory capacity.

Further, when the image memory 119 is constructed with a resolution lower than that of the image forming section 120 and the resolution is enlarged at the time of printing, the character image is deteriorated.
Furthermore, if the number of bits per color component is reduced for each pixel, the number of gradations in the gradation image is reduced.

[0010]

SUMMARY OF THE INVENTION The present invention is intended to solve the above problems, and has the following structure as one means for solving the above problems. That is, in an image processing device for processing image data described in a page description language, a rasterizing unit for rasterizing the image data into raster image data, and raster image data rasterized by the rasterizing unit for each color component data. And a conversion means for converting the color component data read from each plane of the storage means into a predetermined number of bits, the storage means including the number of planes to be assigned to each color component data. Is an image processing apparatus that sets according to the processing mode.

[0011]

With the above arrangement, the raster image data expanded from the image data described in the page description language is stored in a plurality of planes for storing each color component data, and the color components read from each plane are stored. In an image processing apparatus that converts data into a predetermined number of bits, the number of planes assigned to each color component data can be set according to the processing mode.

For example, with the above configuration, a color PD
In the black mode of the L printer, it is possible to provide an image processing apparatus that can effectively use a plane of color component data other than black for developing black component data.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An image processing apparatus according to an embodiment of the present invention will be described in detail below with reference to the drawings.

[0014]

[First Embodiment] FIG. 1 is a block diagram showing the arrangement of an image processing apparatus according to the first embodiment. The image processing apparatus is a color PDL.
It corresponds to. In the figure, the image processing apparatus 50 according to the present exemplary embodiment has a PDL (Page Description) received from the outside.
(Language) data to form an image, and as shown in the figure, an interface 11 and an external interface 6
P sent from the host computer 12 via
The DL data is once stored in the PDL buffer 13 and then expanded into raster image data by the CPU 1,
It is written in the full-page image memory 7. In addition, ROM
2 holds a program executed by the CPU 1, and RAM 3
Is a work memory of the CPU 1, and the font ROM 4 holds information for developing a character code included in PDL data into a bit image, and is a dither pattern ROM.
Reference numeral 5 holds a dither pattern when the dither method, which is one of the binarization methods, is used. RAM, ROM and C
It is connected to the PU1 by the CPU bus 10.

The image memory 7 is a memory for holding raster image data. In the full color mode, four color components (cyan C, magenta M, yellow Y,
Plane 7 of 1 bit / pixel for black K)
It is composed of c, 7m, 7y and 7k. That is, in the full color mode, the raster image data is stored in the image memory 7 as binary data for each color component, so that the multi-valued data included in the input PDL data is
It is written in the image memory 7 after area gradation is performed by a binarization method such as the dither method described above.

In the black mode, the details of which will be described later, in this embodiment, the four planes of the image memory 7 are combined into one image memory for the K component. Therefore,
In the black mode, this embodiment uses 400 dpi, for example.
Since it has a gradation of 4 bits / pixel at a resolution of 16 and has 16 values (4 bits) for the K component, multivalued 16-value conversion such as multivalued dither method is performed, and halftone is multivalued area gradation. Expressed by the method. In general, the multi-value area gradation method using 16-value data has higher image quality than the area gradation method using binary data.

On the other hand, the image forming section 8 is a color printer engine for forming an image, and in the full color mode, forms an image in a frame sequential manner with respect to a plurality of output color components (C, M, Y, K). In this case, each plane of the image memory 7 corresponds to each output color component, and an image is formed based on the image signal 53 read from the image memory 7 and processed. Further, the image forming unit 8 forms an image only for the K component in the black mode.

The address generator 9 generates a read address signal 52 for the image memory 7 based on the synchronizing signal 51 from the image forming section 8. The LUT 16 is a lookup table whose conversion table is set by the CPU 1, and is composed of, for example, a RAM. In the full color mode, the LUT 16 passes any one of the four color component data read from the image memory 7 to the image forming unit 8 in accordance with which color component image the image forming unit 8 forms. For example, the value is multi-valued to 8 bits. In addition, LUT16
In the black mode, the 4-bit K component data read from the image memory 7 is multi-valued into, for example, 8 bits in order to be transferred to the image forming unit 8.

FIG. 2 is a diagram for explaining an example of the conversion table set in the LUT 16. FIG. 11A shows a conversion table set in the LUT 16 when the image forming unit 8 forms an image of the C component. That is, if the C component data sent from the image memory 7 is "0", "0" is output, and if the data is "1", "FF" is output. The same applies to other color components. For example, in the case of forming a K component image in the full color mode,
When the conversion table shown in FIG. 7B is set and the transmitted K component data is "0", "0" is output, and when the data is "1", "FF" is output.

On the other hand, FIG. 7C shows an example of the conversion table set in the LUT 16 in the black mode. That is, if the 4-bit data of the K component sent from the image memory 7 is "0", it is "0", if the data is "1", it is "11", and if the data is "2". If the data is “F”, “FF” is output.

FIG. 3 is a diagram for explaining general PDL data. The PDL typified by the PostScript (registered trademark) language of Adobe Systems Inc. is, as shown in FIG. 3A, (i) image description by character code, (ii) image description by graphic code, (iii) raster. This is a language for describing an image of one page by combining elements such as image description by image data, and the data described by this is PDL data.

FIG. 2B shows an example of a description by a character code, and a portion indicated by 1100 is a description for designating a character color, and the parentheses represent R, G and B intensities in order. The minimum brightness is 0.0 and the maximum brightness is 1.0.
That is, the description specifies the black character color. Next, the part indicated by 1101 is a character string "IC" to the variable string1.
, 1102 is a description for designating the layout of the character string. The first and second parameters are the xy coordinates of the layout start position, the third parameter is the character size, and the fourth is the fourth. The parameter indicates the character spacing, and the fifth parameter indicates the character string to be laid out. That is, the instruction is to lay out the character string stored in the variable string1 with the size of 0.3 from the coordinate (0.0, 0.0) and the character spacing of 0.1.

FIG. 6C shows an example of description by a graphic code, and the portion indicated by 1103 specifies the line color in the same manner as 1100 described above, and the description specifies the red line color.
Next, the portion indicated by 1104 is a description that specifies that a line is drawn, and the first and second parameters are the start position of the line and the third
And the fourth parameter is the xy coordinate of the end position, and the fifth parameter indicates the line thickness. That is, it is an instruction to draw a line with a thickness of 0.1 from the coordinates (0.9, 0.0) to the coordinates (0.9, 1.0).

FIG. 3D shows an example of the description of the raster image.
The part indicated by 105 is a description for substituting the raster image into the variable image1, the first parameter is the image type and the number of color components of the raster image, the second parameter is the number of bits per color component, and the third and fourth parameters. Represents the number of image data in the xy direction of the raster image. The fifth and subsequent parameters are raster image data, and the number of the image data is the product of the number of color components forming one pixel and the number of image data in the xy directions. In the example shown in 1105, the RGB image has three color components. Since it is composed of R, G, and B, the image data is 3 × 5 ×
5 = 75. Next, a portion indicated by 1106 is a description for specifying formation of a raster image. The first and second parameters are start positions of raster image formation, the third and fourth parameters are image sizes in xy directions, and the fifth parameter is. 3 shows a raster image formed by the. That is, it is an instruction to form the image stored in the variable image1 with a size of 0.5 in the x direction and 0.5 in the y direction from the coordinates (0.0, 0.5).

FIG. 4 is a diagram showing a state in which the PDL data shown in FIG. 3 is interpreted and developed into one page of raster image data. In the figure, R100 is the character code of FIG. 3 (b), R101 is the graphic code of FIG. 3 (c), and R102 is the raster image of FIG. 3 (d). In the present embodiment, these PDs are used in the full color mode.
The L data is expanded into raster image data of four color components of CMYK. For example, R100 is expanded into a plane for K component, and R101 is expanded into a plane for M component and Y component. On the other hand, in the case of the black mode, since these PDL data are expanded into raster image data of K color component, each color image data is converted into monochrome by the following formula,
The image is expanded in the image memory 7.

K = (R + G + B) / 3 FIG. 5 is a flow chart showing an example of the image processing procedure of this embodiment. For example, this procedure is executed by the CPU 1 when the power supply of this embodiment is turned on. Is. In the figure, in step S1, the CPU 1 reads the processing mode (full color mode or black mode) instructed by the operation unit (not shown) and sets it as the processing mode. In addition, the processing mode is specified by the host computer 1.
It can be done by command from 2 or P
It can also be embedded in the DL data as a command.

Subsequently, in step S2, the CPU 1 judges whether or not a PDL data reception request is received from the host computer 12, and if there is no such request, the process returns to step S1. If there is such a request, the PDL is received in step S3. Receive one unit of data. Note that one unit may be several bytes or one page, but a size suitable for processing is desirable, and for example, one line unit shown in FIG. 3 is preferable.

Subsequently, the CPU 1 determines in step S4 whether or not it is necessary to develop the received PDL data into a raster image. If it is necessary, the process proceeds to step S5, and if not necessary, step S8. Go to step S9 to execute "other processing" in the same step, and then go to step S9.
The PDL data that needs to be expanded is, for example, as shown in FIG.
1102 in (b), 1104 in (c), and (d) in FIG.
1105, etc., and the PDL data that does not need to be expanded corresponds to, for example, 1100 in FIG. 3A, and in this case, processing such as setting an internal variable is performed in step S8.

When it is necessary to develop a raster image,
In step S5, the CPU 1 determines the set processing mode, and branches to step S6 in the black mode or to step S7 in the full color mode. In the black mode, the CPU 1 executes step S6.
Then, the image memory 7 is used as a 4-bit K component memory to develop K component raster image data. On the other hand, in the case of the full color mode, the image memory 7 is commercialized in step S7.
The raster image data of the CMYK components is expanded by using it as 4 planes of 1 bit each for YK.

Subsequently, the CPU 1 proceeds to step S9, where 1
It is judged whether or not the expansion for one page is completed. If it is completed, the process proceeds to step S10, and if it is not completed, the process returns to step S3, and the development for one page is completed at step S3.
The procedure from step S9 to step S9 is repeated. In addition, normal P
Since the DL data includes information indicating the end of the page such as an EOF (End of File) symbol and information instructing the start of printing, the DL data is used for the determination.

When the development for one page is completed, the CPU 1
In step S10, the conversion table corresponding to the processing mode is set to L
The UT 16 is set, the raster image data read from the image memory 7 is processed by the LUT 16 in step S11, and then the process returns to step S1. If there is the second page or later, the CPU 1 repeats the procedure from step S1 to step S11.

The image forming section 8 which receives the raster image data from this embodiment forms an image of one page. As described above, according to the present embodiment, the image data is expanded from the PDL data with one CMYK bit / pixel in the full color mode, but in the black mode, four planes including three planes for CMY components are included. By expanding the K component data in the image memory for the plane, the image data can be expanded with 4 bits / pixel, so that a high-quality image with 16 gradations can be obtained.

[0033]

[Second Embodiment] Next, a second embodiment according to the present invention will be described. In the second embodiment, the same components as those in the first embodiment are designated by the same reference numerals and detailed description thereof will be omitted. FIG. 6 is a block diagram showing a configuration example of the image processing apparatus of the second embodiment.

The second embodiment shown in FIG. 6 and the first embodiment shown in FIG.
The first difference from the embodiment is that the PDL data is received from the host computer 12 or the like in the first embodiment by communication, but in the second embodiment, from the floppy disk set in the internal floppy disk drive FDD59. PD
It is to read L data. A hard disk drive or the like may be used instead of the floppy disk drive, and PDL data created by an application program (not shown) may be transferred on the main memory.

The second difference is that the image memory 7 in the first embodiment is set to 4 in 1 bit for each of CMYK in the full color mode.
Assigned to a plane, 4 bits K in black mode
Although all the components are assigned, the image memory 7 of the second embodiment has a memory capacity of 12 pages at 1 bit / pixel, and the image memory 7 is assigned to 4 planes of 4 bits each for RGB in the full color mode to obtain a single color ( In the red, green, blue, black) mode, 8 planes are allocated to the monochromatic component of 8 bits (the remaining 4 planes are unused), and in the 2-color mode such as the red / black 2 color mode, 6 bit both color components are allocated. Allocating 6 planes.

In this embodiment, the processing mode has an automatic color mode in addition to these modes. In this automatic color mode, the input PDL data is temporarily read for one page, and the color component used for the one page is determined. Then, the number of planes assigned to each color component is determined according to the determination result. For example, when only red and black are used, it is the same as the above red / black two-color mode, and even when all the color components are used, if the number of gradations of the B component is small, the B component is small. Reduce the number of planes assigned to and increase the number of planes of other color components.

In this embodiment, the RGB and K component data read out from the image memory 7 are respectively stored in the LUT1.
After being converted into 7 bits, for example, in 7, the masking circuit 1
8 is input. The LUT 17 has, for example, 12-bit input and 32-bit output, and a conversion table substantially similar to the conversion table shown in FIG. 2 is set according to the allocation status of the image memory 7.

The masking circuit 18 receives the input RGB signals.
After converting the K component data into CMYK data, the K component data is transferred to the image forming unit 8. The masking circuit 18 is 4
The masking process is executed by a matrix operation of × 4, and the masking coefficient is the form of the image data expanded in the image memory 7 (for example, RGB, RGB and K,
RK, etc.) and determined and set by the CPU 1. Further, which color component data of CMYK the masking circuit 18 outputs depends on which color component of CMYK the image forming unit 8 forms an image.
1 is set.

As described above, according to this embodiment,
In full color mode, image data is expanded from PDL data with RGB and K 3 bits / pixel, but in other processing modes, it should be used for expansion of color component data using a memory plane for unused color components. Thus, the number of bits per pixel of the color component data can be increased as much as possible, and a high quality image with more gradation can be obtained.

In each of the above embodiments, the image forming section 8 and the image processing section 50 are separated from each other.
It is also possible to integrate these. Further, in each of the above embodiments, the image transfer using the so-called video I / F for sending an image by the image signal 53 synchronized with the synchronizing signal 51 is shown, but a general-purpose interface such as GPIB or SCSI is used. You may use and transfer. This general-purpose interface is also used when sending a print start command or the like to the image forming unit 8. In this case, since the transfer speed of the general-purpose interface is generally slower than the image forming speed of the image forming unit 8, the image forming unit 8 requires an image memory for speed conversion.

[0041]

Third Embodiment Next, a third embodiment according to the present invention will be described. In the second embodiment, the same components as those in the first embodiment are designated by the same reference numerals and detailed description thereof will be omitted. FIG. 7 is a block diagram showing a configuration example of the image processing apparatus of the second embodiment.

In the figure, the image processing apparatus 5 of the present embodiment.
0 is the PDL (Page Description Lang) received from the outside.
uage) forms an image represented by the data, and as shown in the figure, the PDL sent from the host computer 12 via the interface 11 and the external interface 6.
Once the data is stored in the PDL buffer 13, C
The raster image data is expanded by the PU 1 and written in the full-page image memory 21 or the image memory 22.

The image memory 21 is an image memory for the K component, and for example, 40 corresponding to the resolution of the image forming section 8.
It has a resolution of 0 dpi and a gradation number of 4 bits per pixel. The image memory 22 is composed of an image memory 22c for C, an image memory 22m for M and an image memory 22y for Y, and has, for example, a resolution of 200 dpi and a gradation number of 8 bits for each color component of one pixel. The PDL data forming one page is expanded in any image memory for each color component according to the resolution and the number of gradations of each image memory.

Each color component memory is constructed so as to have the same number of gradations and the same resolution when viewed from the CPU 1. That is, of the 8 bit data written from the CPU 1, for example, the upper 4 bits are supplied to the image memory 15. Further, of the horizontal and vertical addresses when the CPU 1 performs writing, the lower one bit is removed and supplied to the image memory 22. By configuring the image memory in this way, the CPU 1 can develop raster image data for all color components by the same process.

When the CPU 1 performs the expansion processing for each color component, the image memory may be configured to have different gradation numbers and different resolutions as viewed from the CPU 1. In this case, C
PU1 can perform an optimal expansion process according to the number of gradations and resolution of each image memory. For example, when the number of gradations is 4 bits,
In order to increase the number of apparent gradations, a multi-value area gradation method such as a multi-value dither method can be used.

The raster image data expanded in the two image memories are read out at the time of printing, and the output from the image memory 22 is adjusted to the resolution of the image forming section 8 by the enlarging circuit 23 and then sent to the image forming section 8. To be Enlargement circuit 2
3 is for linearly expanding the number of pixels in each of the vertical and horizontal directions.
For example, 200 dpi image data input from the image memory 22 is adjusted to 400 dp according to the resolution of the image forming unit 8.
Expand to i.

The image forming section 8 is a color printer engine for forming an image, and in the full color mode,
Image formation is performed for a plurality of output color components (C, M, Y, K) in a frame sequential manner. In this case, the image memory 22 is added to each output color component.
And the image memory 21 correspond to each other, and an image is formed based on the image signal 53 read from the image memory and processed.

The address generator 9 generates a read address signal 52 for each image memory based on the synchronizing signal 51 from the image forming section 8. The selector 24 selects one of the four color component data read from the image memory 21 or the image memory 22 according to which color component image is formed by the image forming unit 8 by the CPU 1.

In this embodiment, the K component of the PDL data described with reference to FIGS. 3 and 4 is expanded into raster image data of high resolution and low gradation, and many color components are converted into low resolution and high gradation. Expand to several raster image data. Therefore, according to this embodiment, the character expressed in black is printed with high resolution and low gradation. This is because the character is often expressed in black, and the character portion does not require gradation.

FIG. 8 is a flow chart showing an example of the image processing procedure of this embodiment. For example, this procedure is executed by the CPU 1 when the power supply of this embodiment is turned on. In the figure, the CPU 1 performs PD in step S21.
Receive one unit of L data. Note that one unit may be several bytes or one page, but a size suitable for processing is desirable, and for example, one line unit shown in FIG. 3 is preferable.

Subsequently, the CPU 1 proceeds to step S22,
It is determined whether or not the received PDL data needs to be expanded into a raster image, and if necessary, the process proceeds to step S23, and the raster image data is expanded into the image memory in the same step, and if not necessary, the step is performed. In step S24, "other processing" is executed in the same step. The PDL data that needs to be expanded is, for example, 1102 in FIG.
PDL data such as 1104 in FIG. 3C, 1105 in FIG.
1a of (a) corresponds, and in this case, step S24
Perform processing such as setting internal variables with.

Then, the CPU 1 proceeds to step S25,
It is judged whether or not the expansion for one page has been completed, and if it has been completed, the operation proceeds to step S26, and if it has not been completed, the operation returns to step S21 and returns from step S21 until the expansion for one page is completed. The procedure up to step S25 is repeated. In addition,
The normal PDL data includes information indicating the end of the page such as an EOF (End of File) symbol and information for instructing the start of printing, and the judgment is made based on these.

When the development for one page is completed, the CPU 1
In step S26, the raster image data read out from the image memory is processed and selected and sent to the image forming section 8, and then the process returns to step S21. If there is a second page or later, the CPU 1 repeats the procedure from step S21 to step S26. The image forming unit 8 that has received the raster image data from this embodiment forms an image of one page.

In the above description, an example is described in which low-resolution color components are subjected to enlargement processing to match the resolution with other color components, but in the image forming section 8 where the resolution of each color component is originally different. Can be directly transferred without being enlarged. As described above, according to the present embodiment, with regard to the image memory for storing each color component data expanded from the color PDL data, the K component image memory has a high resolution and a low gradation number, and is used for other color components. Since the image memory of 1 has a low resolution and a high number of gradations, it is possible to reduce the memory capacity required for the image memory while maintaining the high resolution and the high number of gradations of the image to be formed.

[0055]

Fourth Embodiment Next, a fourth embodiment according to the present invention will be described. In the fourth embodiment, the same components as those in the first and third embodiments are designated by the same reference numerals and detailed description thereof will be omitted. FIG. 9 is a block diagram showing a configuration example of the image processing apparatus of the fourth embodiment.

The fourth embodiment shown in FIG. 9 and the third embodiment shown in FIG.
The first difference from the embodiment is that the PDL data is received from the host computer 12 or the like in the third embodiment by communication, but in the fourth embodiment, from the floppy disk set in the internal floppy disk drive FDD59. PD
It is to read L data. A hard disk drive or the like may be used instead of the floppy disk drive, and PDL data created by an application program (not shown) may be transferred on the main memory.

The second difference is that in the third embodiment, the image memory is composed of CMYK, the image memory for the K component has a high resolution and a low gradation number, and the image memories for the other color components have a low resolution. Although the number of gradations is high, in the present embodiment, the image memory is R
The image memory 25 for B component has a low resolution and a low gradation number, and the image memory 26 for other color components has a high resolution and a high gradation number. B component is Y
Image forming unit 8 which is a complementary color of CMYK and forms an image in CMYK
Since the same component is reproduced in Y, the characteristic is used in which the deterioration of the image quality is not noticeable even if the B component has a lower resolution and a lower gradation number than the other components.

The image memory 25 for B is, for example, 200 dpi,
With 6 bits / pixel, the other color component memory 26 has, for example, 4 bits.
It is composed of 00 dpi and 8 bits / pixel. Image memory 25
The B component raster image data read from the
In step 3, the image is interpolated to 400 dpi, for example, and is input to the masking circuit 27 together with the RG component raster image data read from the image memory 26. The masking circuit 27 is R
After converting the GB image data into CMYK image data, it is sent to the image forming unit 8.

As described above, according to this embodiment,
Regarding the image memory for storing each color component data expanded from the color PDL data, the image memory for the B component has a low resolution and a low gradation number, and the image memories for other color components have a high resolution and a high gradation number. Thus, it is possible to reduce the memory capacity required for the image memory while maintaining the high resolution and the high number of gradations of the image to be formed.

The present invention may be applied to a system composed of a plurality of devices or an apparatus composed of one device. Further, it goes without saying that the present invention can also be applied to the case where it is achieved by supplying a program to a system or an apparatus.

[0061]

As described above, according to the present invention, raster image data expanded from image data described in a page description language is stored in a plurality of planes for storing each color component data and read from each plane. In an image processing apparatus for converting color component data into a predetermined number of bits, the number of planes assigned to each color component data can be set according to the processing mode.

Further, according to the present invention, for example, in the image processing apparatus for processing PDL data, the color component data to be used is expanded in the memory plane for the unused color component data according to the processing mode. , Increase the number of bits per pixel of color component data as much as possible,
It is possible to obtain a high quality image with more gradation.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration example of an image processing apparatus of a first embodiment according to the present invention.

FIG. 2 is a diagram illustrating an example of a conversion table set in an LUT of this embodiment.

FIG. 3 is a diagram illustrating general PDL data.

FIG. 4 is a diagram showing how the PDL data shown in FIG. 3 is interpreted and expanded into raster image data for one page.

FIG. 5 is a flow chart showing an example of an image processing procedure of the present embodiment.

FIG. 6 is a block diagram showing a configuration example of an image processing apparatus of a second embodiment according to the present invention.

FIG. 7 is a block diagram showing a configuration example of an image processing apparatus according to a third embodiment of the present invention.

FIG. 8 is a flow chart showing an example of an image processing procedure of the third embodiment.

FIG. 9 is a block diagram showing a configuration example of an image processing apparatus of a fourth embodiment according to the present invention.

FIG. 10 is a block diagram showing a configuration of a printer of Conventional Example 1.

FIG. 11 is a block diagram showing a configuration of a printer of Conventional Example 2.

[Explanation of symbols]

 1 CPU 6 External Interface 7, 21, 22, 25, 26 Image Memory 8 Image Forming Section 9 Address Generator 12 Host Computer 16, 17 LUT 18, 27 Masking Circuit 23 Enlargement Circuit 24 Selector

Claims (11)

[Claims] 1. An image processing apparatus for processing image data described in a page description language, comprising rasterizing means for rasterizing the image data into raster image data, and colorizing the raster image data rasterized by the rasterizing means. The storage means comprises a plurality of planes for storing each component data, and a conversion means for converting the color component data read from each plane of the storage means into a predetermined number of bits, the storage means assigning to each color component data. An image processing apparatus, wherein the number of planes is set according to a processing mode. 2. The image processing apparatus according to claim 1, wherein the color components are CMYK. 3. The image processing apparatus according to claim 2, wherein a color component forming an image is selected from the CMYK in accordance with the processing mode. 4. The image processing apparatus according to claim 1, wherein the color components are RGB and K. 5. The image processing apparatus according to claim 4, wherein color components forming an image are selected from the RGB and K according to the processing mode. 6. The image according to claim 3, wherein the processing mode includes a black mode using only the K component, and in the black mode, all of the planes are allocated for the K component. Processing equipment. 7. An image processing apparatus for processing image data described in a page description language, wherein data of a first color component included in the image data is first
Raster image data of a second resolution and raster data of a second color component different from the first color component included in the image data is raster image data of a second resolution different from the first resolution. Developing means, first storage means for storing the raster image data of the first color component developed by the developing means, and storing raster image data of the second color component developed by the developing means And a second storage unit for performing the image processing. 8. The image processing according to claim 7, further comprising conversion means for converting the raster image data of the second resolution read from the second storage means into the first resolution. apparatus. 9. An image processing apparatus for processing image data described in a page description language, wherein data of a first color component included in the image data is first
Of raster image data having a number of gradations of 2 to 3 and data of a second color component different from the first color component contained in the image data having a second number of gradations different from the first number of gradations. Rasterizing means for rasterizing raster image data, first storing means for storing raster image data of the first color component rasterized by the rasterizing means, second color component rasterizing by the rasterizing means And a second storage unit for storing the raster image data of 1. 10. The image processing apparatus according to claim 7, wherein the first color component is black and the second color component is other than black. . 11. The method according to claim 7, wherein the first color component is blue or yellow, and the second color component is other than blue or yellow. Image processing device.