JP3203660B2 - Image recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording apparatus capable of outputting texts and graphics in a page description language.

[0002]

2. Description of the Related Art In recent years, when texts and graphics created by a computer or the like are output using a printer, a page description language PDL has begun to be used as information communication means between the two. A page description language, for example, in the case of outputting text, communicates to a printer a font type, an output size, a position on an output sheet, and the like in a predetermined format. Some are called by Interpress. A printer control unit that processes such a page description language interprets the information and converts the information into a format that can be output on paper such as pixel-based data, and controls the printer based on the format.

FIG. 8 shows a conventional example of an image recording apparatus for fetching and processing digital information in a page description language (Japanese Unexamined Patent Publication No.
No. 67159), an outline of which will be described below.

In the example shown in FIG. 8, when the page description language is sent from the host computer 21 via a standard interface such as GP-IB or SCSI, the translation unit 2
3 is sequentially decoded by the CPU 24 on the
The editing information stored in the screen configuration information table in the table is sequentially rewritten by the CPU 24. As described above, the translation unit 23 includes the screen configuration information table, and editing information other than video data such as drawing, characters, drawing, and information from the host computer 21 is stored in the same pixel as the page memory 26 in the bitmap format. Is written so as to correspond to one body. When the editing is completed and a print request is made, various types of graphic data and text data such as coordinate conversion, characters, graphics, and density are synchronized with the video clock CLK generated from the memory driver 25 based on the screen configuration information table. Image processing is performed, and the image is sent to the memory driver 25 in real time. The memory driver 25 generates an address and records video data corresponding to the position information from the translation unit 23 in the R, G, and B page memories 26. The page memory 26 is configured in a so-called bitmap format in which a pixel position on the output paper and each bit of the memory have a one-to-one correspondence, and one pixel has a bit number according to the expression capability of the printer. Page memory 2
The full-color image information developed on 6 is given a raster scan address synchronized with the recording unit 82 to the page memory 26 from the printer driver 27, and is read as a raster image.

[0005]

However, when an image is output to a laser printer or the like in the above-described image recording apparatus, pixel data must be expanded in a page memory for one page, and a large memory is required. There is a problem of doing. Further, when pixel data for one page is held as multi-gradation data, for example, at 256 gradations, each pixel needs to have a depth of 8 bits, and the above problem becomes more remarkable. When it comes to a color image, three sheets of R (red), G (green), and B (blue), and for a full color toner, Y (yellow), M (magenta),
Four page memories of C (cyan) and K (black) are required, and a huge memory capacity of about 100 megabytes is required for A3 size.

In view of the above, it is an object of the present invention to provide an image recording apparatus which can decode a sentence or figure described in a page description language, develop it with a small amount of memory, and hold and output the result. is there.

[0007]

Therefore, the image recording apparatus of the present invention can decode a sentence or figure described in a page description language, develop it into image information, and output it as image information. In an image recording apparatus, means for decoding a sentence or figure described in a page description language and expanding it into image information, means for compressing the expanded image information, or means for compressing /
It is characterized in that it comprises means for decompressing and means for holding compressed data, and is configured to hold the decompressed image information as compressed data.

[0008]

According to the image recording apparatus of the present invention, means for decoding a sentence or figure described in a page description language and expanding it into image information, means for compressing expanded image information or means for compressing / expanding, Is provided, image information obtained by expanding texts and graphics described in the page description language can be stored as compressed data, and the memory capacity can be reduced.

[0009]

Embodiments will be described below with reference to the drawings.

FIG. 1 is a diagram showing an embodiment of an image recording apparatus according to the present invention, FIG. 2 is a diagram showing an example in which an output image is divided into 16 blocks, and FIG. It is a figure for explaining.

In FIG. 1, a communication unit 1 is connected to, for example, a host computer, and a page description language sent from the host computer is decoded by a translation unit 2 via the communication unit 1 and developed into image information. . The block management unit 3 manages image information from the translation unit 2 and the compression / decompression unit 5 by dividing the image information into predetermined blocks. The buffer memories 4-1 and 4-2 store the divided block sizes. It is a buffer of a bitmap format. The compression / decompression unit 5 compresses the image information sent from the block management unit 3 in block units, stores the compressed image information in the compressed data holding memory 6, and reads out the compressed data from the compressed data holding memory 6 in block units. The compressed data is decompressed and sent to the block management unit 3 or the compressed data is read from the compressed data holding memory 6 in synchronism with the clock from the recording unit 8 and decompressed and sent to the line buffer 7. That is, when a sentence or graphic described in the page description language is developed in a predetermined block in the buffer memory 4-1 or 4-2,
The compressed data at the position corresponding to the block is read from the compressed data holding memory 6, expanded by the compression / expansion unit 5, and synthesized. Then, the synthesized image information is compressed /
The data is compressed by the decompression unit 5 and written into the compressed data holding memory 6. Then, when outputting the compressed data in the compressed data holding memory 6 to the recording unit 8, the compressed data is read from the compressed data holding memory 6, expanded by the compression / expansion unit 5, and stored in the line buffer 7.

Next, the processing of the image recording apparatus of the present invention will be described by taking as an example a case where an output image is set in 16 blocks as shown in FIG. 2 (a).

When the output image is divided into blocks as shown in FIG. 2A, the buffer memories 4-1 and 4-2 store
The compressed data holding memory 6, which has the same size as the one block, is also divided into blocks each having a size for holding compressed data of a size corresponding to this block, as shown in FIG.

Therefore, the blocks (1, 1), (1, 2), (2, 2) in FIG.
When it is instructed to draw a circle at a position straddling 1) and (2, 2), when this is expanded into pixels, expansion, synthesis, and compression processing are performed in the flow shown in FIG. Done. First,
Assuming that the circle starts from the block (1, 1) and is drawn counterclockwise, the block management unit 3 keeps the expanded pixels within the range of the block (1, 1) as shown in FIG. The image information is developed in the buffer memory 4-1. Then, when the developed pixel exceeds the range of the block (1, 1) and enters the range of the block (2, 1), the developed pixel is developed in the buffer memory 4-2 as shown in FIG. Switch. Note that the contents of the buffer memory 4-1 at this time are combined with the data obtained by expanding the block (1, 1) of the compressed data holding memory 6 by the compression / expansion unit 5, and the result is compressed to obtain the buffer memory 4-2. Write processing is performed on the block (1, 1) of the compressed data holding memory at the same time as the data is expanded.

Similarly, the developed pixels are divided into blocks (2,
When entering the range of the block (2, 2) beyond the range of 1), switching is performed so as to be developed in the buffer memory 4-1 as shown in FIG. Also at this time, the contents of the buffer memory 4-2 are combined with the data obtained by expanding the block (2, 1) of the compressed data holding memory 6 by the compression / expansion unit 5, and the result is compressed to obtain the compressed data holding memory. Write to block 6 (2, 1).

In this manner, the data is alternately developed in the buffer memories 4-1 and 4-2, as shown in FIG.
By performing the processing of (e), blocks (2, 2) and (1, 2)
When the result of the decompression is compressed and finally written in the block (1, 2) of the compressed data holding memory 6, the operation of interpreting and decompressing the page description language relating to the circle is completed.

The above processing is repeated for each page description language. Therefore, each block of the compressed data holding memory 6 is a block which is repeated every time there is an expansion of a sentence or graphic described in the page description language in the buffer memory 4-1 or 4-2 from a white background to pixels. , The compressed data is read out from the storage unit, decompressed by the compression / decompression unit 5, synthesized, and the result is updated by compressing and writing the result again.

FIG. 4 is a diagram showing an embodiment of block division suitable for processing text information such as characters, and FIG. 5 is another image recording apparatus according to the present invention suitable for processing text information such as characters. It is a figure showing an example composition.

A block is developed in all directions when it comes to graphic information such as an image, but it is usually developed in a horizontal direction at a constant width when it comes to text information such as a character.
The block division shown in FIG. 4 is such that the blocks have the length in the horizontal direction of the output image range, and are configured so as to be suitable for processing of text information such as characters. In other words, when such block division is used, when the output image is a horizontally written sentence, the probability that the developed pixels enter the same block increases, so that the number of times of block switching can be reduced. Therefore, for example, the size of each block is reduced by dividing the block so that the vertical and horizontal lengths become the number of pixels of the power of 2, and the capacity of the buffer memory is reduced. By reducing the number of memories (the minimum is two), the memory capacity used for the buffer memory can be reduced.

Further, as shown in FIG. 5, a character code translating unit 9 is provided to add a conventional character font generating function, so that information transmitted in a conventional character code other than the page description language can be converted into a character font. When the image data is expanded into a buffer, the buffer memory can be used as a line buffer without using compression / decompression.

FIGS. 6 and 7 show another embodiment of the image recording apparatus according to the present invention.

In the above embodiment, the compressed data holding memory is also divided into blocks in accordance with the block division of the output image, and two buffer memories of the size corresponding to the block are provided to alternately expand and contract as described above. Added compression processing. Also, one compression / decompression unit and one memory for holding compressed data are provided. In contrast, compression /
FIG. 11 is a block diagram showing an example in which a switching unit 10 is added so as to have two or more decompression units and two or more compressed data holding memories, and to combine the decompressed pixel data and continuously output the data to a recording unit. 6 is FIG. Thereby, when the operation speed of the compression / decompression is slower than the other operation speeds, a partial parallel operation is performed, thereby making it possible to reduce the trouble due to the difference in the operation speed. In this case, the selection of the buffer memory to be stored in the compressed data holding memory is performed in order from the oldest history of the history expanded last.

FIG. 7 shows an example in which the read image and the page description are obtained by combining the image recording apparatus of the present invention with a copying machine including an image reading section 11, an image processing section 12, and a recording section 13. It is constructed so that the result of interpreting and expanding the language can be synthesized and output.

It should be noted that the present invention is not limited to the above embodiment, and various modifications are possible. For example, in the above embodiment, the image information is expanded in the buffer memory in a certain order. However, if there is a buffer memory holding the image information of the same block as the block to be expanded, the image is synthesized and expanded. If such a buffer memory does not exist, the buffer memory may be expanded to an available buffer memory. Further, each block of the compressed data holding memory has a register for holding whether or not each block is a blank in a state where characters, graphics, etc. are not expanded, and
If the corresponding block is blank with reference to this register, the contents of the buffer memory may be directly compressed without writing the decompression and combination processing and written to the corresponding block of the compressed data holding memory.

[0025]

As is clear from the above description, according to the present invention, the compressed data after the output image is divided into blocks and the page description language is expanded and compressed in block units is compressed data holding memory. Therefore, the storage capacities of the buffer memory and the compressed data holding memory can be reduced.

As an example, when a color laser printer compatible with a page description language of 24 bits per pixel and 400 pixels per inch is used, it is necessary to use an expansion memory to output A3 size image information by a conventional method. Is about 9
You need 6 megabytes. On the other hand, if the compression ratio is 10:
In the configuration of the present invention in which three 1-megabyte buffer memories are used as 1, the memory usage of about 13 megabytes is required. Therefore, the memory capacity and cost can be reduced.

When it is necessary to hold the image information of a plurality of pages, the system using the present invention can cope with the problem by increasing the memory for holding the compressed data. , A3 size can save about 86 Mbytes per page, and the effect is even more remarkable.

[Brief description of the drawings]

FIG. 1 is a diagram showing one embodiment of an image recording apparatus according to the present invention.

FIG. 2 is a diagram illustrating an example of a case where an output image is divided into 16 blocks.

FIG. 3 is a diagram for explaining a compression storage process.

FIG. 4 is a diagram showing an embodiment in which blocks are divided so as to be suitable for processing of text information such as characters.

FIG. 5 is a diagram showing another embodiment of an image recording apparatus suitable for processing text information such as characters.

FIG. 6 is a diagram showing the configuration of another embodiment of the image recording apparatus according to the present invention.

FIG. 7 is a diagram showing the configuration of another embodiment of the image recording apparatus according to the present invention.

FIG. 8 is a diagram illustrating a conventional example of an image recording apparatus that captures and processes digital information in a page description language.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Communication part, 2 ... Translation part, 3 ... Block management part, 4-1 and 4-2 ... Buffer memory, 5 ... Compression / decompression part, 6 ...
Memory for holding compressed data, 7: line buffer, 8: recording unit

──────────────────────────────────────────────────の Continued on front page (51) Int.Cl. ⁷ Identification code FI H04N 1/41 G06F 15/66 330A

Claims (12)

(57) [Claims] An image recording apparatus capable of decoding a sentence or figure described in a page description language, developing it into image information, and outputting it as image information. It is provided with a means for decoding a figure and expanding it into image information, a means for compressing expanded image information, and a means for holding compressed data, and configured to hold the expanded image information as compressed data. An image recording apparatus, comprising: 2. The image recording apparatus according to claim 1, wherein a memory space of one page in which the image information is expanded by the expansion unit is divided into blocks, and compression is performed in block units. 3. The image processing apparatus according to claim 2, wherein the expanding unit has at least two buffer memories each having a size equivalent to one block obtained by dividing a memory space of one page into which image information is expanded. 2. The image recording apparatus according to 2. 4. The image recording apparatus according to claim 2, wherein the size of the block is a number of pixels whose length and width are powers of two. 5. When a page description language is decoded by the expansion means and expanded into image information, the image data is expanded in one of the buffer memories, and a coordinate of a character or a graphic to be expanded is expanded. 4. The image recording apparatus according to claim 3, wherein when the size of the memory is exceeded, the image is switched to another buffer memory and developed. 6. An image recording apparatus capable of decoding a sentence or figure described in a page description language, developing it into image information, and outputting the image information as a sentence or figure described in a page description language. Means for decompressing a figure to expand it into image information, means for compressing / expanding the expanded image information, and means for holding compressed data, so that the expanded image information is held in compressed data. An image recording apparatus characterized by comprising. 7. The image recording apparatus according to claim 6, wherein a memory space of one page in which the image information is expanded by the expansion unit is divided into blocks, and compression / expansion is performed in block units. . 8. The image processing apparatus according to claim 1, wherein said developing means has at least two buffer memories each having a size equivalent to one block obtained by dividing a memory space of one page into which image information is developed. 8. The image recording device according to 7. 9. The decompression means selects one or more of the buffer memories for which decompression work has been completed, combines them with decompressed data of the corresponding block in the compressed data holding memory, and compresses / decompresses them. 9. The image recording apparatus according to claim 8, wherein the combining unit compresses the combined result, stores the compressed result in the corresponding block, and makes a buffer memory usable. 10. The decompressing means decompresses compressed data in a compressed data holding memory corresponding to a block to be decompressed by a decompressing / decompressing means and stores the decompressed data in a buffer memory. 9. The image recording apparatus according to claim 8, wherein the image information is developed. 11. Compression / expansion means and means for holding compressed data are respectively provided in two or more, and compression / expansion work of a plurality of buffer memories can be performed in parallel, and pixel data after expansion is combined. 7. The image recording apparatus according to claim 6, wherein the image can be output to a recording unit. 12. The apparatus has two or more means for compressing / expanding and means for holding compressed data, and reads out compressed data from the holding means in synchronization with a clock from a recording unit to perform the compression / expansion. 7. The image recording apparatus according to claim 6, wherein the image data is expanded by means and sent to a line buffer.