JP2000099290A - Device and method for controlling print - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable print-out at all the time even when continuous printing is requested to a printer by executing the comparison of sizes between the size of a compressed data memory and a compressed image data size and further determining whether or not compression processing is to be executed again. SOLUTION: At the time of initial setting, a print control part 42 detects the size of a compressed image buffer memory 45 to input compressed images. When a print request instruction comes, the decomposition of first page and compression of image are performed by a decomposing part 43 and compression part 44. When the first page is completely compressed by the compression part 44, a size discriminating part 421 in the print control part 42 judges the compressed data size and when the size exceeds an evaluation value, compression is performed again. When the compressed data are completely generated, a printer 48 is activated and the compressed data are outputted to the printer 48 through the compressed image buffer memory 45, a storage device 47 as needed and an extension/transfer part 46.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for interpreting and decomposing an image data file expressed in, for example, a PDL (Page Description Language), compressing the data as compressed data, decompressing the data, and outputting it to an output device. The present invention relates to a print control apparatus and a print control method having a compression unit that converts a compressed image format into a compressed image format that can be expanded at an output speed required by a printer as an output device.

[0002]

2. Description of the Related Art Printing apparatuses for performing printing using an electrophotographic system are widely used, including copying machines. Such electrophotographic printing is widely used not only for copying machines but also for printers connected to computers and for printing images. A typical example of such a printer is a laser beam printer. The laser beam printer prints data by expanding coded image data or compressed image data into image data for each pixel.

FIG. 1 shows a schematic configuration of a print control unit for a conventional monochrome laser printer. FIG. 2 shows the control flow.

First, from a client or an application on a computer, a request reception storage unit 11 receives control information for printing on an output device such as a printer 16 and a file described in a page description language (PDL).
Received at

Next, the control information and the PDL file received by the request receiving and storing
Then, the PDL file is output to the decomposing unit 13. The decomposing unit 13 decomposes the input PDL file, develops it into bitmap data for each pixel, and stores it in a bitmap memory (also called a page memory).
14 is stored.

[0006] Finally, an instruction for printing and an instruction for an interface for transferring bitmap data are given to the printer 16, and the bitmap is transferred to the printer 16 via a transfer I / F (interface) 15. 16 for printing.

In such a bitmap transfer, when several pages are continuously printed in the printer 16, it is necessary to continuously output bitmaps corresponding to the number of output sheets. Therefore, data transfer is repeatedly performed for the number of prints.

The conventional print control flow shown in FIG. 2 will be briefly described. First, the print control device waits for data input (step 201), and when data is input, stores the data in the storage unit (the request reception storage unit 11 in FIG. 1). The stored data is sent to the control unit 12 and the decompose unit 13 as described above. If it is determined in step 203 that there is data to be printed, a decompose instruction is output from the control unit 12 to the decompose unit 13 (step 204), and the decompose unit 1
3 decomposes the input PDL file according to the instruction. The control unit 12 outputs a data transfer print instruction to the transfer interface 15 based on the decomposed state and the output preparation state in the printer (step 205). The bitmap data decomposed by the decomposing unit 13 and stored in the bitmap memory 14 is output to the printer 16 via the transfer I / F 15 in accordance with the output instruction.

[0009]

In an electrophotographic printer, generally, paper that has been sent once cannot be stopped in the middle of printing, and therefore, when printing different pages continuously or when performing double-sided printing, The bitmap memory for a plurality of pages for continuous printing is held in the bitmap memory, and the data for the plurality of pages for continuous printing stored in the bitmap memory is synchronized with the output speed of the printer as an output device. Output is required. For this reason, the bitmap memory needs to have a capacity enough to store bitmaps for a plurality of pages continuously printed by the printer. For example, the bitmap is 600
The A4 size color is about 140 MB in dpi (dot per inch). To prepare this for a plurality of pages, the memory size increases, and the cost and power consumption of the apparatus become too high.

As a conventional method for solving the above-mentioned problem, Japanese Patent Laid-Open Publication No. Hei 7-137360 discloses a method of performing double-sided printing, that is, having a limited capacity when printing by a printer cannot be interrupted. A configuration that switches the resolution only for double-sided printing in order to hold all bitmap data on both sides in the bitmap memory.In the case of double-sided printing, the compression rate is higher than that for single-sided printing, and the data per page is increased. Disclosed is a configuration in which a bitmap of a double-sided page is stored in a bitmap memory with a reduced amount, and low-resolution bitmap data can be continuously output from the memory to a printer to perform double-sided printing. . The method described in JP-A-7-137360 is based on the premise that image data is stored in a bitmap memory, and a bitmap memory for one page is required. Even when this method is used, depending on the content of image data on a page, all data on both pages may exceed the memory capacity. Errors may occur, and it does not guarantee complete double-sided printing or continuous printing.

Further, as a method of avoiding an increase in the bitmap memory capacity, there has been proposed a print control method of recompressing (also called re-encoding) data that can be output to a printer in real time by a decomposing unit.
FIG. 3 shows the configuration of this prior art.

The configuration of FIG. 3 will be described briefly. FIG.
In the same manner as in the configuration described above, control information and a page description language (hereinafter referred to as PD) for printing from an application on a client or
The file described in L) is received in the request reception storage unit 31. The control information and the PDL file received by the request reception storage unit 31 are stored in the control unit 32 as P
The DL file is output to the decompose unit 33. The decomposing unit 33 decomposes the input PDL file, and outputs this to the compression unit 34 to perform data compression. This is a data format that can be output to a printer 38 in real time, and the compressed data is transferred to a decompression unit / transfer unit 36 via a compressed image buffer memory 35.
After the compressed data is decompressed, the data is transferred to the printer 38. Information such as each data transfer timing is output to each device by an output signal from the print control unit 32. If necessary, a storage device 37 is provided for storing the compressed data generated by the compression unit 34.

The compression method in the case of the print control apparatus having the configuration shown in FIG. 3 includes a case where the compression ratio is prioritized and a case where the image quality is prioritized. For example, JP-A-9-81
No. 763 discloses a method for keeping the compression ratio at a constant value. Such a configuration in which the compression ratio is kept constant has a disadvantage that the image quality deteriorates when a complicated image is input.

In Japanese Patent Application Laid-Open No. 9-222969, data of a predetermined page is stored in accordance with the size of compressed data that can be input into a memory, that is, the capacity of a page that can be input into a memory. A method is described in which only a few minutes of printing is continuously printed by a printer, and an overflow is printed in the next cycle. This configuration has a drawback that printing is interrupted, for example, when the total size of both sides is larger than the buffer memory for storing the compressed image.

In view of the above-mentioned drawbacks of the prior art, the present invention can always perform print output even when continuous printing is required in a printer, for example, when performing double-sided printing. It is another object of the present invention to provide a print control device and a print control method that can optimize the print control.

[0016]

To achieve the above object, a print control apparatus according to the present invention comprises: a decomposing means for interpreting input image data; a compression means for compressing image data interpreted by the decomposing means; Compression data memory for storing compressed image data compressed by the compression means, decompression processing means for executing decompression processing of the compressed image data stored in the compression data memory, and output means for outputting the data decompressed by the decompression processing means A size of a compressed data memory holding compressed image data generated by the compression means and a size of a compressed image data size generated by the compression means in the print control apparatus having a transfer means for transferring the compressed image data generated by the compression means. The compression processing is executed again based on the determination by the determination unit and the size determination unit. And having a control means for determining Luke.

Further, in the print control apparatus according to the present invention, when the input image data is double-sided print data, the size determining means determines the size of the compressed data memory,
The compression unit is configured to compare the compressed image data size of the front (front) surface of the compressed image data generated by the compression unit with the double-sided data size which is the sum of the compressed image data sizes of the back surface. I do.

Further, in the print control apparatus according to the present invention, when the input image data is double-sided print data and the compression process is executed again, the control means performs a recompression process on only one side or a recompression process on both sides. It is characterized by having a configuration for selecting which one to execute.

Further, in the print control apparatus according to the present invention, the size determining means sets the size of the compressed data memory to b.
s, the compressed data size of one page or one color of image data compressed by the compression means is fs, the compressed data size of the front (front) surface compressed by the compression means is fs1, and the compressed data size of the back surface is fs2. At this time, a comparison formula composed of functions f (bs), g (bs), fs1, and fs2 of the compressed data memory size bs, f (bs)> =
The size comparison is performed based on fs and g (bs)> = fs1 + fs2.

Further, in the print control apparatus of the present invention, the function f (bs) of the compressed data memory size: bs,
g (bs) is characterized in that it is defined as f (bs) = bs, g (bs) = bs.

Further, in the print control apparatus of the present invention, the function f (bs) of the compressed data memory size: bs,
g (bs) is f (bs) = bs / 2, g (bs) = b
It is characterized by being defined as s.

Further, in the print control apparatus of the present invention, the function f (bs) of the compressed data memory size: bs,
g (bs) is f (bs) = any fixed value, g (bs)
= Defined as any fixed value

Further, in the print control apparatus according to the present invention, when the input image data is continuous page print data, the size determination means determines the size of the compressed data memory and the continuous page print of the compressed image data generated by the compression means. It is characterized in that the configuration is such that the sum of the compressed image data size of each page of data is compared with the total page data size.

Further, in the print control apparatus according to the present invention, the recompression processing when the control means determines recompression processing based on the determination by the size determination means is applied to the compression processing executed by the compression means. The compression parameter is changed.

Further, in the print control apparatus according to the present invention, when the input image data is color print data, the size determination means determines the size of a compression data memory for each color provided for each output color in the output means, A means for comparing the data size of the compressed image data for each color generated by the means with the data size.

Further, in the print control apparatus according to the present invention, when the input image data is color print data, the size determination means determines the size of a compressed data memory provided for each predetermined combination of output colors in the output means;
The present invention is characterized in that a comparison is made with the data size of compressed image data for each predetermined combination of output colors generated by the compression means.

Further, in the print control apparatus of the present invention, when the control means determines that recompression is necessary for any of the output colors based on the determination by the size determination means,
The present invention is characterized in that it has a configuration in which recompression applying the same compression parameter to all output colors is performed by the compression means.

Further, according to the print control method of the present invention, an interpreting step for interpreting the input image data, a compression processing step for compressing the image data interpreted in the interpreting step, and a process for compressing the compressed image data compressed in the compression processing step. A storage step for storing in a compressed data memory;
In a print control method having a decompression processing step of executing decompression processing of compressed image data stored in a compression data memory and a transfer step of transferring data decompressed in the decompression processing step to output means, The size of the compressed data memory holding the compressed image data to be compressed and the size of the compressed image data generated in the compression processing step. It is characterized in that it is determined whether or not to execute the processing again.

Further, in the print control method according to the present invention, when the input image data is double-sided print data, the size determining step includes a table of the size of the compressed data memory and the compressed image data generated in the compression processing step. The front side is characterized in that a comparison is made between a two-sided data size, which is the sum of the compressed image data size of the front side and the compressed image data size of the back side.

[0030]

[First Embodiment] FIG. 4 is a block diagram showing an embodiment of a print control apparatus and a print control method according to the present invention. FIG. 5 shows a print control flow according to this embodiment.
Shown in

An embodiment of the print control apparatus of the present invention shown in FIG. 4 will be described. The request reception storage unit 41 receives control information for printing on an output device such as the printer 48 and a file described in a page description language (PDL) from a client or an application on a computer. Regarding the control information and the PDL file received by the request reception storage unit 41, the control information is output to the control unit 42 and the PDL file is output to the decomposing unit 43. The decomposing unit 43 decomposes the input PDL file, and outputs this to the compression unit 44 to perform data compression.

Data compression in the print control apparatus of the present invention is performed according to the following procedure. (1) First, the print control unit 42 detects the size of the compressed image buffer memory 45 in which the compressed image is stored (at the time of initialization). This process is performed only at the time of the initial setting. After the size of the compressed image buffer memory 45 is detected, the detected size is stored and held, and thereafter, it is not necessary to execute the process. (2) When a print request instruction is received, first, the first page is decomposed and the image is compressed.
3 and the compression section 44. (3) When the compression of the first page is completed in the compression section 44, the size determination section 421 in the print control section 42
, The compressed data size is determined, and if the size exceeds the evaluation value, recompression is performed. Size determination unit 4
The determination of the compressed data size, the evaluation value, and the recompression in 21 will be described later in detail. (4) In the case of a double-sided printing request, after the front (front) surface is compressed, the back surface is further compressed by the compression unit 44, and the size determination unit 421 in the print control unit 42 determines the front and back surfaces. Is determined, and if the size exceeds the evaluation value, recompression is performed. (5) The above steps (2) to (2) until the generation of the compressed data related to the page necessary for starting the printer 48 is completed.
Repeat (4). (6) Activate the printer 48 and output the compressed data to the printer 48 via the compressed image buffer memory 45, the storage device 47, and the decompression / transfer unit 46 as necessary. (7) Repeat steps 2 to 6 until the last page.

The compressed data generated by compression in the compression section 44 or recompression performed based on the determination of the size determination section 421 has a data format that can be output to the printer 48 in real time.
Decompression / transfer unit 4 via compressed image buffer memory 45
6, the compressed data is decompressed, and then transferred to the printer 48. Information such as each data transfer timing is output to each device by an output signal from the print control unit 42. If necessary, a storage device 47 is provided for storing the compressed data generated by the compression unit 44.

In steps (3), (4) and (3) described above, when the compression of the first page is completed in the compression section 44, the size determination section 421 in the print control section 42
, The compressed data size is determined, and if the size exceeds the evaluation value, recompression is performed. (4) In the case of a double-sided printing request, after the front (front) surface is compressed, the back surface is further compressed by the compression unit 44, and the size determination unit 421 in the print control unit 42 determines the front and back surfaces. Is determined, and if the size exceeds the evaluation value, recompression is performed. The determination of the compressed data size, the evaluation value, and the recompression in the size determination unit 421 will be described in detail.

First, regarding the above step (3), when the size of the compressed image buffer memory 45 in the print control apparatus of the present invention shown in FIG. The data size is fs. At this time, the size determination unit 421 of the print control unit 42 determines that a function represented by bs, f (bs)> = fs. . . . . . (1) It is determined whether or not.

The size determination unit 421 determines that the data size when one page or one color of image data is compressed by the compression unit 44 does not satisfy the above equation (1), f (bs)> = fs. The print control unit 42 sends an instruction to recompress this page or one color image data to the compression unit 4.
4, and the compression unit 44 executes recompression in accordance with the recompression instruction from the print control unit 42. The compression unit 44
The recompression is performed, and the size determination unit 421 also performs the above equation (1), f (bs)> =
fs is determined, and recompression is repeated until this equation (1) is satisfied.

Next, in the step (4) of executing re-compression in double-sided printing, if the double-sided printing is specified, the size of the compressed image buffer memory 45 in the print control unit is bs and the compression unit 44 compresses the image. The compressed data size of the front (front) surface is fs1, and the compressed data size of the back surface is fs2. At this time, the size determination unit 42 of the print control unit 42
1 is a function represented by bs, g (bs)> = fs1 + fs2. . . . . . (2) It is determined whether or not.

When the size determination unit 421 determines that the data size when the image data on both sides is compressed by the compression unit 44 does not satisfy the above expression (2), g (bs)> = fs1 + fs2, the print control unit Reference numeral 42 outputs an instruction to recompress the image data on the back or front and back to the compression unit 44, and the compression unit 44 executes recompression according to the instruction for recompression from the print control unit 42. The compression unit 44 performs recompression, and the size determination unit 421 also performs the above equation (2), g (bs)> = fs1 + on the recompressed data.
The determination of fs2 is performed, and the recompression is repeated until this equation (2) is satisfied.

FIG. 5 shows a print control flow in the print control apparatus of the present invention described above. Hereinafter, each step of the control flow will be described.

First, as an initial setting, the print control device executes the detection of the buffer memory amount (bs) in step 501. This is a step of detecting the capacity of the compressed image buffer memory 45 in FIG. 4 as described above. If the detected capacity is registered in the print control unit 42 by executing this step, the execution of this step 501 is omitted in the subsequent printing operation.

Waiting for data input to the request reception storage unit 41 of FIG. 4 (step 502), the input data is stored in the request reception storage unit 41 (step 503).
When data is input to the request reception storage unit 41, the print control unit 42 receives control information and determines whether or not data is present (step 504). Step 502,
Reference numeral 503 denotes processing in the request reception storage unit 41. Since the flow after step 504 is mainly performed by the print control unit, the flow is divided and shown.

If it is determined in step 504 that there is data, the P
The DL file is decomposed and the compression unit 4
At 4, the compression process is performed. Next, the data size of the data compressed by the compression unit 44 is determined (Step 506). This data size judgment is
This is performed in the size determination unit 421 in the print control unit 42. The determination performed in step 506 is a determination based on the above-described expression (1), and the size of the compressed image buffer memory 45 is set to bs, the data size when one page or one color image data is compressed by the compression unit 44. Is set to fs, and the determination of Expression (1), f (bs)> = fs, for the function f (bs) represented by bs is executed.

If it is determined in step 506 that the above equation (1) is Yes, the process proceeds to step 507, and
If it is, the process proceeds to step 510.

In step 510, the compression parameter in the compression processing executed by the compression section 44 is changed. The size of the compressed data differs due to the change in the compression parameter. When the compression parameter is changed in step 510, recompression using the changed compression parameter is performed in the compression unit 44.

Further, the expression (1) and the determination of f (bs)> = fs are performed in step 506 for the recompressed compressed data size. The above steps are repeated in step 506 until equation (1) is satisfied.

If the determination in step 506 is Yes,
Proceeding to step 507, it is determined whether or not the compressed data is data on the back side. If it is determined that it is the back side, the process proceeds to step 511, where the size of the compressed image buffer memory 45 in the print control device is set to bs,
The compressed data size of the front (front) surface when compressed by the compression unit 44 is fs1, and the compressed data size of the back surface is fs2, and the size determination unit 421 performs a function represented by bs, g (bs)> = fs1 + fs2. . . . . . (2) It is determined whether or not.

The determination in step 511 is No,
If the result of the double-sided compression does not satisfy Expression (2), the process proceeds to step 512. In step 512, it is determined whether to recompress both surfaces or only one surface. This determination is based on fs1 + fs2 used for the comparison in step 511.
Is determined on the basis of the data size and the like. Or fs1
The determination is made based on a predetermined criterion, such as based on the difference between the data sizes of the data and fs2.

For example, f (bs) = bs, g (bs) =
bs, the compressed image size on the front (front) surface is fs1
= Bs * 3/4, compressed image size on the back side is fs2 = bs
In the case of * 1/2, the expression (2) is not satisfied when the back surface data is created. In this case, not the back surface but only the front (front) surface is recompressed. To obtain the same image quality on both the front (front) surface and the back surface, both are recompressed.

When performing double-sided compression, step 51
Proceeding to 3, the compression parameters on both sides are changed, and recompression based on the changed parameters is returned to step 505 to execute compression on each side. If it is determined in step 512 that recompression is performed on one side, the process proceeds to step 510, in which the parameters are changed on only one side and recompression is performed. These steps are repeated until the determination in step 511 becomes Yes.

If the determination in step 511 is Yes, that is, if g (bs)> = fs1 + fs2 is satisfied, the flow advances to step 508 to determine whether the scheduled data processing has been completed.
Alternatively, it is determined whether the total compressed data has reached a predetermined appropriate amount, for example, the capacity of the compressed image buffer memory 45, or the capacity determined based on the capacity of the compressed image buffer memory 45 and the storage device 47. If not, return to step 504 and repeat the same steps. If it is determined in step 508 that the scheduled processing has been completed, the process proceeds to step 509, where the compressed data accumulated in the compressed image buffer memory is transferred to the decompression / transfer unit 4.
The print data is transferred to the printer 48 through the decompression process in step 6, and printing by the printer 48 is started.

The above is the basic configuration and basic flow in the print control apparatus of the present invention. Print control unit 42
The size determination unit 421 determines the size of the compressed image buffer memory 45 as bs, 1
The data size when the page or one color image data is compressed by the compression unit 44 is fs, the compressed data size of the front (front) surface when compressed by the compression unit 44 is fs1, and the compressed data size of the back surface is fs2. And f (bs)> = fs. . . . . . (1) g (bs)> = fs1 + fs2. . . . . . (2) The comparison shown in is performed, where f
The print control apparatus of the present invention has different aspects depending on how the relation between (bs) and g (bs) and the capacity of the compressed image buffer memory: bs is set. Less than,
The various aspects will be described.

[Example 1] The above equations (1) and (2) f (bs)> = fs. . . . . . (1) g (bs)> = fs1 + fs2. . . . . . In (2), it is assumed that f (bs) = bs and g (bs) = bs.

By setting f (bs) = bs and g (bs) = bs, f (bs) and g (bs) become the buffer size itself. As a result of this setting, by satisfying the above expression (1) or (2), even for one page alone, the compressed data: fs is equal to or smaller than the compressed image buffer memory size, and the compressed data for two pages: fs1 + fs2 is also equal to or smaller than the buffer size. be able to.

A method of executing such a determination of the compressed data size in the size determination unit 421 to determine whether or not the compressed data is larger than the compression buffer memory size, and to execute recompression when the size is larger. As a result, it is possible to perform appropriate compression according to the capacity of the buffer memory, it is possible to guarantee data output to the printer without performing excessive compression, and a low compression ratio giving priority to image quality is low. A configuration can be realized.

Example 2 Equations (1), (2), f (bs)> = fs. . . . . . (1) g (bs)> = fs1 + fs2. . . . . . In (2), it is assumed that f (bs) = bs / 2 and g (bs) = bs.

Thus, f (bs) = bs / 2, g (b
By setting s) = bs, the same compression ratio is obtained on one side or both sides.

Example 3 Formulas (1), (2), f (bs)> = fs. . . . . . (1) g (bs)> = fs1 + fs2. . . . . . In (2), f (bs) = an arbitrary fixed value, and g (bs) = an arbitrary fixed value.

Thus, f (bs) = any fixed value, g
By setting (bs) = arbitrary fixed value, the compression result can be set to a fixed fixed size regardless of the buffer size. For example, by adding a buffer memory, printing can be realized at higher speed. become.

Although the above embodiment has been described mainly with respect to double-sided printing, the present invention is not limited to double-sided printing. In the printer 48 (FIG. 4), recompression is performed in consideration of the capacity of the compressed image buffer memory 45 and the number of pages to be continuously printed. Can be determined.

In this case, the determination of the above equation (2) is different. When continuous page printing is specified, the size of the compressed image buffer memory 45 in the print control device is bs, the compressed data size of the first page when compressed by the compression unit 44 is fs1, and the compressed data size of the second page To fs2. . . Hereinafter, the compressed data size of the nth page is fsn. At this time, the size determination unit 421 of the print control unit 42 outputs a function represented by bs, g (bs)> = fs1 + fs2 +. . . . . . fn. . . . . (3) It is determined whether or not.

The size determination unit 421 determines that the data size when the image data of the continuous page is compressed by the compression unit 44 is the above equation (2), g (bs)> = fs1 + fs2
+. . . . . . If it is determined that fn is not satisfied, the print control unit 42 outputs an instruction to recompress these image data to the compression unit 44, and the compression unit 44
The recompression is executed in accordance with the recompression instruction from Step 2. Note that the compression in this case can be set to any predetermined setting such as only the last page or all pages. The compression unit 44 performs a predetermined recompression, and the size determination unit 421 also performs the above equation (3), g (bs)> = fs1 + fs2 on the recompressed data.
+. . . . . . The determination of fn is performed, and re-compression is repeated until Expression (3) is satisfied.

Embodiment 2 Hereinafter, another embodiment of the print control apparatus of the present invention will be described. This embodiment relates to a color printer.

In the case of a color printer, it is necessary to prepare compressed data for four or six colors used for the printer. When compression processing is performed for each color, decompression processing can also be performed for each color. By configuring a decompression device for each color, it is possible to determine the compressed data size independently for each color, and it is also possible to calculate the added data size by combining the compressed data of multiple colors Becomes

FIG. 6 shows a four-color printer of four colors, for example, C (cyan), M (magenta), Y (yellow), and K (black). An example of determining gender will be described.

An embodiment of the print control apparatus of the present invention shown in FIG. 6 will be described. A request reception storage unit 601 receives control information for printing on an output device such as a printer 608 and a file described in a page description language (PDL) from a client or an application on a computer. Request receiving storage unit 60
In the control information and PDL file received in step 1, the control information is output to the print control unit 602, and the PDL file is output to the decomposing unit / compression unit 603. Decompose part
The compression unit 603 decomposes the input PDL file and further compresses it.

The data compressed by the decomposing section / compressing section 603 is stored in two compressed image buffer memories 60.
4 is output. For example, in C (cyan), M (magenta), Y (yellow), and K (black), in this example, one set of C (cyan) and M (magenta), and one set of Y (yellow) and K (black)
The data is combined as a set of data and output to each compressed image buffer memory 604.

The size determination unit 6021 determines whether C (cyan),
One set of data of M (magenta), Y (yellow), K (black)
Size determination is executed for each of the set of data. These determinations are similar to the method described in the first embodiment.

However, in this configuration example, two decompressors 605
And a buffer memory for each decompressor is prepared. For example, when the decompressor 605 is used in time division or in parallel for two channels, for example, the sum of black and yellow is equal to or less than the buffer size: bs (or It is sufficient that the size of the compressed data of black is fsk, and the size of the compressed data of yellow is fsy.
Then, f (bs)> = fsk + fsy. . . . . . (4)

The compression may be performed so as to satisfy the above expression (4). Similarly, in the case of double-sided data, if the compressed data size of the black table is fs1k, the back is fs2k, the compressed data size of the yellow table is fs1y, and the back is fs2y, then g (bs)> = fs1k + fs2k + fs1y + fs2y. . . . . . (5)

The execution of recompression may be determined depending on whether or not the above expression (5) is satisfied.

Based on the above equations (4) and (5), the size determination unit 421 makes a determination, and the compressed data generated by compression or recompression has a data format that can be output to the printer 608 in real time. . The compressed data is supplied to the decompression unit 6 via the compressed image buffer memory 604.
The data is sent to the memory 606 for each color, and is output to the printer 608 via the transfer unit 607. Information such as each data transfer timing is output to each device by an output signal from the print control unit 602.

[Embodiment 3] Another embodiment of the print control apparatus of the present invention in a color printer will be described.

In the second embodiment, if the compressed data does not satisfy the condition of the above equation (4) or (5), recompression is performed until each equation is satisfied. If one color is recompressed, the image quality of only that color may be degraded.

Embodiment 3 is a configuration in which the deterioration of each color is prevented and the image quality of each color is substantially the same. In order to prevent deterioration for each color and to achieve the same image quality for each color, the present configuration compresses each color using the same compression parameter. With this configuration, the image quality of each color can be averaged.

That is, in this configuration, in FIG. 6, when only one of the two compressed image memories 604 does not satisfy the above equations (4) and (5),
Instead of changing the compression parameter of only the color data stored in any of the memories and performing recompression of only one of the colors (or a set of colors), the compression of one of the colors (or the set of colors) is not performed. If you need to perform recompression,
Perform recompression of all colors (or sets of colors) using the same compression parameters.

According to the configuration of this embodiment, compression processing is performed using the same parameters without using different parameters for each color, so that there is no difference in image quality deterioration for each color, and natural color Reproduction is possible.

[0077]

As described above, according to the print control apparatus and print control method of the present invention, for example, in a high-speed and high-quality laser printer, the size of the compressed image data is compared with the size of the buffer memory for storing the image. And recompressed as needed,
It is possible to realize a print control method capable of reliably performing printing on both sides or continuous pages.

According to the print control apparatus and the print control method of the present invention, recompression is performed as needed based on the size of the buffer memory, so that excessive compression can be prevented and the compression ratio can be optimized. And the image quality can be optimized. Also, when considering a change in the compression ratio due to the addition of a buffer memory, by comparing the changed buffer memory size with the compressed image data, it is possible to obtain an optimal image quality according to the buffer memory size. This makes it possible to perform data transfer accompanied by optimal compression / decompression processing in accordance with the printing speed.

[Brief description of the drawings]

FIG. 1 is a configuration example of a conventional print control device (part 1).
FIG.

FIG. 2 is a diagram illustrating a print control flow of a conventional print control device.

FIG. 3 is a configuration example of a conventional print control device (part 2).
FIG.

FIG. 4 is a diagram illustrating a configuration (first embodiment) of a print control apparatus according to the present invention.

FIG. 5 is a diagram showing a print control flow of the print control device of the present invention.

FIG. 6 is a diagram illustrating a configuration (second embodiment) of a print control apparatus according to the present invention.

[Explanation of symbols]

 41 request reception storage unit 42 print control unit 43 decomposition unit 44 compression unit 45 compressed image buffer memory 46 decompression unit / transfer unit 47 storage device 48 printer 421 size determination unit 601 request reception storage unit 602 print control unit 603 decompose unit 604 compressed image Buffer memory 605 Decompression unit 606 Memory 607 Transfer unit 608 Printer 6021 Size determination unit

Claims (14)

[Claims] A decomposing means for interpreting input image data; a compression means for compressing image data interpreted by the decomposing means; a compressed data memory for storing compressed image data compressed by the compression means; A print control apparatus comprising: a decompression processing unit for performing decompression processing of compressed image data stored in a compression data memory; and a transfer unit for transferring data decompressed by the decompression processing unit to an output unit. A size determination unit that performs a size comparison between the size of the compressed data memory that holds the compressed image data generated in step S1 and the size of the compressed image data generated by the compression unit; Control means for determining whether or not to execute the compression process again. A print control device comprising: 2. The method according to claim 1, wherein the size determining unit determines a size of the compressed data memory and a front side of the compressed image data generated by the compressing unit when the input image data is double-sided print data. 2. A configuration for performing a comparison of a double-sided data size, which is a sum of a compressed image data size of the back surface and a compressed image data size of the back surface, with the double-sided data size.
The print control device as described in the above. 3. When the input image data is double-sided print data and the compression process is executed again, the control unit selects whether to execute one-side recompression process or two-side recompression process. 3. The print control device according to claim 2, further comprising: 4. The apparatus according to claim 1, wherein the size determination unit determines a size of the compressed data memory as bs, and a size of compressed data of one page or one color image data compressed by the compression unit as fs.
Assuming that the compressed data size of the front (front) surface compressed by the compression means is fs1 and the compressed data size of the back surface is fs2, the function f (b) of the compressed data memory size bs
s), a comparison formula composed of g (bs) and the fs1 and fs2, f (bs)> = fs, and g
3. The print control device according to claim 2, wherein the size comparison is performed based on (bs)> = fs1 + fs2. 5. The function f (bs) and g (bs) of the compressed data memory size: bs is f (bs) = bs, g
5. The print control apparatus according to claim 4, wherein (bs) = bs. 6. The function f (bs) and g (bs) of the compressed data memory size: bs is f (bs) = bs / 2,
5. The print control apparatus according to claim 4, wherein g (bs) = bs. 7. The functions f (bs) and g (bs) of the compressed data memory size: bs are defined as f (bs) = any fixed value and g (bs) = any fixed value. 5. The print control device according to claim 4, wherein: 8. When the input image data is continuous page print data, the size determination unit determines the size of the compressed data memory and each of the continuous page print data of the compressed image data generated by the compression unit. 2. The print control apparatus according to claim 1, wherein a comparison is made between the total sum of the compressed image data sizes of the page and the total page data size. 9. A method according to claim 9, wherein:
2. The re-compression process when the control unit determines re-compression process is performed by changing a compression parameter applied to a compression process performed by the compression unit. Print control device. 10. When the input image data is color print data, the size determination unit determines a size of a compressed data memory for each color provided for each output color in the output unit, and the size of the compressed data memory generated by the compression unit. 2. The print control apparatus according to claim 1, wherein the print control apparatus is configured to perform comparison with the data size of the compressed image data for each color. 11. When the input image data is color print data, the size determination unit determines the size of a compressed data memory provided for each predetermined combination of output colors in the output unit, and the size generated by the compression unit. 2. The print control apparatus according to claim 1, wherein a comparison is made with the data size of the compressed image data for each predetermined combination of the output colors. 12. The control unit, if it is determined that recompression is required for any of the output colors based on the determination by the size determination unit, the control unit applies the same compression parameter to all of the output colors. The print control device according to claim 10, further comprising a control unit configured to control compression to be performed by the compression unit. 13. An interpreting step for interpreting input image data, a compression processing step for compressing the image data interpreted in the interpreting step, and storing the compressed image data compressed in the compression processing step in a compressed data memory. A print control method, comprising: a storage step; a decompression processing step of performing decompression processing of compressed image data stored in the compressed data memory; and a transfer step of transferring data decompressed in the decompression processing step to output means. A size determination step of performing a size comparison between a size of the compressed data memory holding the compressed image data generated in the compression processing step and a size of the compressed image data generated in the compression processing step; For the judgment in the judgment step A print control method for determining whether or not to execute the compression process again on the basis of the result. 14. The size judging step, wherein, when the input image data is double-sided print data, a size of the compressed data memory and a table (front) of compressed image data generated in the compression processing step 2. The configuration according to claim 1, wherein a comparison is made between the size of the compressed image data on the front side and the size of the double-sided data composed of the sum of the sizes of the compressed image data on the back side.
3. The print control method according to 3.