JPH0825716A - Electrophotographic page printer - Google Patents

Abstract

PURPOSE:To enable precision in printing to be maintained by enabling reduction of a manufacturing cost to be achieved. CONSTITUTION:A page data buffer 1 wherein one page content of a printing data is stored in a code state, a developing mechanism part 3 wherein a bit map image data D2 is developed from the printing data D1, and a frame buffer 4 is provided for storing a fraction. of one page of the bit map image data in the developed bit map image D2. A data compressing part 6 wherein the image data D2 is successively stored by compressing, and one page content of compressed data D3 is restored, and a compression data buffer 7 are provided. When time required for development is judged to be within specific time with the control part 2, the image data D2 of the frame buffer 4 is successively printed with a printing mechanism part 9. Further, when time required for development is judged to be outside the specific time, one page content of the image data D2 restored with a compressed data-restoring part 8 is printed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic page printer capable of printing one page of print data at a time.

[0002]

2. Description of the Related Art In an electrophotographic page printer, the process of printing operation cannot be stopped midway.
This is because there are processes such as exposure to the photosensitive material, transfer of toner, fixing of toner, etc. during the process of the printing operation, so if the speed of this process is changed or stopped, the characteristics of those processes will be affected. Because a big change will occur. That is, the printing cannot be performed, the printing density and the positional accuracy are extremely lowered, or the paper is deformed due to excessive heat applied to a part of the paper. Therefore, most of the current electrophotographic printers print in the minimum unit that can perform the above process at one time, that is, in page units. Further, in order to guarantee that "the printing operation is not stopped in the middle of a page", at least one page of data is completely received, and printing is started after the data of that page is confirmed.

Conventionally, as electrophotographic page printers for printing such one page, one having a frame buffer for storing one page of data, one having a frame buffer for storing a part of data, compressed data There are three types of printers for printing.

An electrophotographic page printer having a frame buffer for storing data for one page has 0 pages of image information, which is a printing unit, without performing any processing.
Alternatively, it is provided with a frame buffer that stores information of 1. This printer receives print data from a higher-level device, analyzes the print data, develops data such as characters and graphics into printable image data as it is, and draws it in a frame buffer. The printing operation is started when all the data for one page has been drawn. Therefore, at the time of the printing operation, one page of data is ready for printing as it is, and there is no need to stop the printing operation on the way.

Further, the printing mechanism of the electrophotographic page printer having a frame buffer for storing a part of data is as follows. For example, in Japanese, JIS
If the character code defined by the above is used, the storage capacity of 2 bytes per character will suffice. However, if this is expressed in the form of image data on the frame buffer, a capacity of 100 to 1000 bytes is required.

Therefore, in this type of printer, instead of storing one page of data in the frame buffer, a page data buffer for storing the character code is newly provided, and the capacity of the frame buffer is reduced to several minutes. The load is reduced by setting one page to several tens of minutes. As a result, it has become possible to significantly reduce the amount of memory required.

In this electrophotographic page printer, the data received from the host device is stored in the page data buffer as it is or after a certain process (conversion) is performed on the data. Then, the reception of the data for one page is completed, and when the data is gathered in the page data buffer, the drawing to the frame buffer is started. At this time, since the capacity of the frame buffer is not enough for one page, only the data corresponding to the upper end portion of the paper is first drawn.

When the printing operation progresses and a printed portion is generated in the frame buffer, the drawing of the data immediately after the first drawn portion is started. This drawing is
It is completed by the time the printing of the first drawn portion is completed. Therefore, at the same time as the printing of the first drawn portion is completed, the printing of the subsequent portion can be continuously performed.
By simultaneously performing drawing and printing using a limited memory in this way, drawing and printing for one page are performed.

Further, the electrophotographic page printer for printing with compressed data has a memory corresponding to a frame buffer capable of storing a bit image for one page, and the image data for one page is stored therein by image processing. It is compressed and stored. For this compression, a method such as MH, MR, MMR adopted in a facsimile or the like or a compression method used in an image filing system or the like is used. As a result, the memory corresponding to the frame buffer can be made extremely small.

[0010]

However, the above-mentioned conventional electrophotographic page printer has the following problems. An electrophotographic page printer having a frame buffer that stores one page of data must be equipped with a frame buffer that has a sufficient amount of memory to store one page of print data in a bit image state. . This memory imposes a heavy burden on the printer, occupies a considerable proportion of the printer manufacturing cost, and causes a problem of cost increase.

Further, an electrophotographic page printer having a frame buffer for storing a part of data has an advantage that printing can be performed with a small memory, but in some cases it may not be possible to actually print correctly. That is, when drawing a character in an outline font or a complicated figure, the drawing time is long. When these time-consuming drawing operations are performed simultaneously with the printing operation, there occurs a situation in which the drawing of the portion following the band that is currently being printed is not completed by the end of printing. In such a situation,
Printing cannot be stopped just because the drawing is not completed, so the data of the part where the drawing could not be completed is made blank or all the subsequent parts are made blank ("Overrun" is printed). ")).

Further, in an electrophotographic page printer which prints with compressed data, generally, the compression rate of data at the time of image data compression changes depending on the content of the image. In an extreme example, the data amount may not decrease at all or may increase. The printer must be able to print any kind of data, and it becomes difficult to save memory when dealing with such an extreme case. Further, considerable processing is required for compression and decompression of image data. Generally, in order to achieve a practical compression ratio, it is often necessary to perform compression and decompression by hardware. Particularly in the case of a printer, the restoration process must be performed at the same time as the printing operation and at a speed not lower than the printing speed. If this cannot be realized, the restoration process will not be in time and an overrun will occur.

As described above, the above-mentioned conventional electrophotographic page printer has a big problem in terms of manufacturing cost and printing accuracy. As technologies similar to the above-mentioned conventional electrophotographic page printer, there are technologies described in Japanese Patent Application Laid-Open Nos. 2-184344 and 2-177421. However, these technologies do not solve the above problems. Absent.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an electrophotographic page printer capable of reducing the manufacturing cost and maintaining the printing accuracy. .

[0015]

In order to achieve the above object, an electrophotographic page printer of the present invention includes a page data buffer for storing print data for one page in a code state, and printing in the page data buffer. An expansion mechanism unit that expands and generates bitmap image data from the data, a frame buffer that can store bitmap image data that is a fraction of one page out of the bitmap image data expanded and generated by the expansion mechanism unit, The bitmap image data of this frame buffer is sequentially compressed and stored, and compressed data for one page can be restored / compressed.
Based on the restoring means, the print data in the page data buffer, a control unit that determines whether or not the expansion required time in the expansion mechanism unit is within a specified time, and the controller requires a expansion time within the specified time. When it is determined that the bit map image data of the frame buffer is sequentially printed, and when it is determined that the required expansion time is out of the specified time,
A printing mechanism unit that prints the bitmap image data for one page is provided.

According to another aspect of the electrophotographic page printer of the present invention, the compression / decompression means compresses the bitmap image data of the frame buffer.
A configuration including a compressed data buffer that sequentially stores the compressed data compressed and formed by the data compression unit, and a compressed data decompression unit that decompresses the compressed data for one page in the compressed data buffer into the original bitmap image data. There is.

An electrophotographic page printer according to a third aspect of the present invention includes a hard disk capable of storing at least one page of bitmap image data in the frame buffer, and the control unit is based on the print data in the page data buffer. It is determined whether or not the expansion required time in the expansion mechanism unit is within the specified time, and when it is determined that the expansion required time is outside the specified time, the compression ratio in the compression / decompression means is further restored. It is to judge whether the operation is proper or not, and the printing mechanism section, in the control section, sequentially prints the bitmap image data of the frame buffer when it is judged that the required development time is within a specified time, Also, the required expansion time is outside the specified time, and the compression ratio and the restoration operation in the compression / decompression means are correct. When it is determined that one page of bitmap image data restored by the compression / decompression means is printed, the required expansion time is outside the specified time and the compression ratio or the decompression operation in the compression / decompression means is performed. 1 in the above hard disk when is determined to be non-
The configuration is such that bitmap image data for pages is printed.

According to a fourth aspect of the present invention, in the electrophotographic page printer, based on the judgment of the control section, the bitmap image data in the frame buffer is transferred to the printing mechanism section,
The configuration is such that a compression / decompression means and a selection means for leading to either the hard disk are provided.

[0019]

According to the above electrophotographic page printer, when the print data for one page is stored in the page data buffer in the code state, it is expanded into the bitmap image data by the expansion mechanism section, and the bitmap image is generated. Bit map image data corresponding to a fraction of one page of the data is stored in the frame buffer. And
When the control unit determines that the required expansion time in the expansion mechanism unit is within the specified time, the printing mechanism unit sequentially prints the bitmap image data in the frame buffer. Further, when the control unit determines that the required expansion time is out of the specified time, the compression / decompression unit sequentially compresses and stores the data, and the restored bitmap image data for one page is printed by the printing mechanism unit. .

According to the electrophotographic page printer of the second aspect, the data compression section of the compression / decompression means compresses the bitmap image data in the frame buffer, and the compressed data is sequentially stored in the compressed data buffer. When one page of compressed data is stored in the compressed data buffer, the compressed data decompression unit decompresses the original bitmap image data.

According to the electrophotographic page printer of the third aspect, when the control unit determines that the required development time is within the specified time, the printing mechanism unit sequentially prints the bitmap image data in the frame buffer. ,
If it is determined that the required expansion time is outside the specified time and the compression ratio and the decompression operation in the compression / decompression unit are correct, the printing mechanism unit restores one page decompressed by the compression / decompression unit. The bitmap image data of is printed. When it is determined that the expansion required time is outside the specified time and the compression ratio or the decompression operation in the compression / decompression means is non-existent, the printing mechanism unit copies the bitmap image data for one page in the hard disk. Printed.

According to another aspect of the electrophotographic page printer of the present invention, the selecting means selects the bitmap image data in the frame buffer from the printing mechanism section, the compression / decompression means, and the hard disk based on the judgment of the control section. Lead to crab.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. First embodiment. FIG. 1 is a block diagram showing an electrophotographic page printer according to a first embodiment of the present invention. As shown in FIG. 1, the electrophotographic page printer of this embodiment includes a page data buffer 1, a control unit 2, a decompression mechanism unit 3, a frame buffer 4, a switching unit 5 as a selection unit, and a data compression unit. It includes a unit 6, a compressed data buffer 7, a compressed data decompression unit 8, and a printing mechanism unit 9.

The page data buffer 1 is a memory for storing the print data D1 received from the higher-level device in the state of a code instead of an image, and the print data D for one page.
It has a capacity capable of storing 1.

The control unit 2 has a function of switching the switching unit 5 in consideration of the amount of print data D1 stored in the page data buffer 1. Specifically, the print data D1 stored in the page data buffer 1 is monitored,
From the content of the print data D1, the time T required for the print data D1 to be expanded by the expansion mechanism unit 3 is predicted. That is, when the expansion of the print data D1 is, for example, the expansion of an outline font or complicated graphic data, the expansion time in the expansion mechanism section 3 becomes long.

Further, the expansion time differs depending on the amount of data per page. Therefore, the control unit 2
Checks whether the print data D1 does not include the above data, and if it is determined that the print data D1 includes the above data,
A control signal C for connecting the frame buffer 4 and the data compression unit 6 is output to the switch 5.

When it is determined that the frame is not included, the control signal C for connecting the frame buffer 4 and the printing mechanism section 9 is output to the switch 5. This judgment is based on the specified time T which is the preset necessary time T.
It is performed depending on whether it is greater than 0.

The expansion mechanism section 3 includes a page data buffer 1
It has a function of inputting the print data D1 in the code state stored in, generating bit map image data corresponding to the data content, and storing it in the frame buffer 4.

The frame buffer 4 is a memory for storing the bit map image data D2 from the expansion mechanism section 3, and is a small capacity memory capable of storing the bit map image data D2 of a fraction of one page.

The switch 5 is switched by the control signal C from the control section 2 so as to send the output of the frame buffer 4 to the data compression section 6 or the printing mechanism section 9.

The data compression unit 6 has a function of compressing the printable bitmap image data D2 from the frame buffer 4 and storing the compressed data D3 in the compressed data buffer 7.

The compressed data decompression unit 8 inputs the compressed data D3 in the compressed data buffer 7 and receives the compressed data D3.
Is restored to the original bitmap image data D2. The decompression function by the compressed data decompression unit 8 and the compression function by the data compression unit 6 are achieved by hardware. However, the invention is not limited to this, and the compression and decompression functions can be achieved by software.

The printing mechanism unit 9 is for printing the bitmap image data D2 from the frame buffer 4 or the compressed data decompression unit 8 on a recording medium (not shown). Specifically, when the printing mechanism unit 9 is directly connected to the frame buffer 4 via the switch 5, a small amount of bitmap image data D2 stored in the frame buffer 4 is sequentially read and printed. . If the printing mechanism unit 9 is not connected to the frame buffer 4 but is connected to the compressed data decompression unit 8, the one page of bitmap image data D2 decompressed by the compressed data decompression unit 8 is used. It is designed to print at once.

Next, the operation of this embodiment will be described.
FIG. 2 is an operation flowchart of the present embodiment. When the print data D1 for one page received from the host device is stored in the page data buffer 1 in the code state, the print mechanism D3 reads the print data D1.
It is developed into bitmap image data D2 corresponding to the data content and stored in the frame buffer 4 (steps S1 to S3 in FIG. 2). At this time, since the frame buffer 4 can store only a fraction of the bitmap image data D2 of one page, the bitmap image data D2 indicating the portion corresponding to the band near the top of the page is stored in the frame buffer 4 ( Below "drawing"
That).

In parallel with this operation, the control unit 2
Print data D1 stored in page data buffer 1
Is monitored, and the time T required for the print data D1 to be expanded by the expansion mechanism section 3 is predicted from the contents of the print data D1 (step S4 in FIG. 2).

If the expansion by the expansion mechanism unit 3 is not the expansion of outline fonts or complicated graphic data, or the expansion of a small amount of data per page, the expansion necessary time T is less than the specified time T0. Therefore, the control signal C connecting the frame buffer 4 and the printing mechanism unit 9 is output from the control unit 2 to the switch 5 (YES in step S4 of FIG. 2).

As a result, the bitmap image data D2 in the frame buffer 4 is sequentially read by the printing mechanism unit 9 and printed. That is, when the data corresponding to the band near the top of the page is written in the frame buffer 4, the bitmap image data D2 is read and printed by the printing mechanism unit 9. And
After drawing the bitmap image data D2 showing the data of the portion following the band near the top of the page where the drawing is performed in the empty frame buffer 4, the bitmap image data D2 is read and printed. This operation is sequentially repeated to complete drawing and printing for one page (step S9 in FIG. 2).

As described above, when the expansion by the expansion mechanism unit 3 is not the outline font or the expansion of complicated graphic data, or the expansion of a small amount of data per page, the bitmap image data D2
Is sequentially written to and read from the frame buffer 4, and the bitmap image data D2 is printed in synchronization therewith, so that the above-mentioned "overrun" phenomenon does not occur.

If the expansion by the expansion mechanism unit 3 is expansion of outline fonts or complicated graphic data, or expansion of a large amount of data per page, the expansion necessary time T is the specified time. Since it becomes larger than T0, the control signal C for connecting the frame buffer 4 and the data compression unit 6 is output from the control unit 2 to the switch 5, and the bit map image data D2 in the frame buffer 4 is output by the data compression unit 6. After being compressed, the compressed data D3 is stored in the compressed data buffer 7 (NO in step S4 of FIG. 2 and steps S5 and S6).

That is, when the data corresponding to the band near the top of the page is written in the frame buffer 4,
The bitmap image data D2 is read out and sent to the data compression unit 6 via the switch 5. And
After this data is compressed by the compression unit 6, it is stored in the compressed data buffer 7 as compressed data D3. Next, after drawing the bitmap image data D2 showing the data of the portion following the band near the top of the page where the drawing has been performed in the vacant frame buffer 4, the bitmap image data D2 is read and compressed. It is stored in the compressed data buffer 7. This process is sequentially repeated (NO in step S7 of FIG. 2, steps S5 and S).
6).

When the compressed data D3 for one page is stored in the compressed data buffer 7, the compressed data D3 for one page is read out from the compressed data buffer 7, and the compressed data decompression unit 8 sets a bitmap. After being restored to the image data D2, the printing mechanism unit 9 prints at once (YES in step S7 of FIG. 2, steps S8 and S9). The decompression operation in the compressed data decompression unit 8 is performed in synchronization with the printing operation of the printing mechanism unit 9.

As described above, when the expansion by the expansion mechanism unit 3 is the expansion of the outline font or the complicated graphic data, or the expansion of a large amount of data per page, it is compressed and compressed. 1 in data buffer 7
Since the page is stored and one page is printed at a time, the above-mentioned "overrun" phenomenon does not occur.

Further, the memory capacity of the frame buffer 4 should be reduced to a fraction of one page, and the memory capacity of the compressed data buffer 7 should be reduced to a fraction of one to several tenths when storing uncompressed data. Therefore, the memory can be saved, and as a result, the cost can be reduced.

Second embodiment. FIG. 3 is a block diagram showing an electrophotographic page printer according to the second embodiment of the present invention. The same elements as those of FIG. 1 will be described with the same reference numerals. This embodiment is different from the first embodiment in that a hard disk is provided. That is, the first
In the embodiment, normal printing is possible by compressing and decompressing data that requires time for expansion and drawing.
The following problems may occur in printing by this compression and decompression.

First, depending on the content of the print data D1, the compression rate of the data compression section 6 may not be sufficient, and in such a case, the compressed data buffer 7 contains a bitmap image for one page. The data D2 cannot be stored. Second, the compressed data decompression unit 8
Restoring operation and the printing operation of the printing mechanism unit 9 must be synchronized, and the restoring speed must not be lower than the printing speed. However, the restoring speed may not catch up with the printing speed depending on the content of the print data D1. . Compressed data decompression unit 8
If such a situation is configured by hardware, the occurrence of such a situation can be considerably suppressed, but in the case where the decompression operation of the compressed data decompression unit 8 is to be achieved by software for simplification of the device, There are many situations in which it becomes a serious problem. Therefore, in this embodiment, as the configuration shown in FIG.
It was decided to avoid the above situation and ensure normal printing.

The control unit 10 in FIG. 3 has a function of switching the switch 20 between three stages in consideration of the content and amount of the print data D1 stored in the page data buffer 1. Specifically, the time T required for the print data D1 to be expanded by the expansion mechanism unit 3 is predicted from the contents of the print data D1, and if the expansion necessary time T is within the specified time T0, the frame buffer 4 A control signal C for connecting to the printing mechanism unit 9 is output to the switch 20.

When the required expansion time T is longer than the specified time T0, the control unit 10 examines the contents of the print data D1. As a result, the compression rate of the data compression unit 6 is sufficient, and the compressed data When it is determined that the restoring operation of the restoring unit 8 is synchronized with the printing operation of the printing mechanism unit 9 (“Yes”), the control signal C for connecting the frame buffer 4 and the data compressing unit 6 is output to the switch 20. . vice versa,
As a result of the data content examination, when it is determined that the compression ratio of the data compression unit 6 is insufficient and the decompression operation of the compressed data decompression unit 8 cannot catch up with the printing operation of the printing mechanism unit 9 (“non”). ), Frame buffer 4 and hard disk 3
It has a function of outputting a control signal C for connecting 0 to the switch 20. At least one hard disk 30
It has a capacity capable of storing bitmap image data D2 for pages.

Next, the operation of this embodiment will be described.
When the print data D1 for one page received from the host device is stored in the page data buffer 1 in the code state,
The data is read by the expansion mechanism unit 3 and expanded into bitmap image data D2 corresponding to the data content,
It is stored in the frame buffer 4.

In parallel with this operation, the control unit 10 monitors the print data D1 stored in the page data buffer 1 and determines whether the expansion necessary time T in the expansion mechanism unit 3 is within the specified time T0. . When the control unit 10 determines that the required development time T is within the specified time T0, the frame buffer 4 and the printing mechanism unit 9 are connected, and the bitmap image data D2 in the frame buffer 4 is transferred to the printing mechanism unit 9 Are sequentially read out and printed.

Then, the control unit 10 judges that the expansion required time T is longer than the specified time T0, and as a result of examining the contents of the print data D1, the compression ratio of the data compression unit 6 is sufficient, and the compressed data When it is determined that the restoration operation of the restoration unit 8 is synchronized with the printing operation of the printing mechanism unit 9, the frame buffer 4 and the data compression unit 6 are connected, and the bitmap image data D2 in the frame buffer 4 is data-compressed. After being compressed by the unit 6, the compressed data D3 is stored in the compressed data buffer 7. When the compressed data D3 for one page is stored in the compressed data buffer 7, the compressed data D3 for one page is read from the compressed data buffer 7 and restored to the bitmap image data D2 by the compressed data decompression unit 8. After printing, the printing mechanism unit 9 prints at once.

On the contrary, as a result of the data content examination by the control unit 10, the compression ratio of the data compression unit 6 is insufficient,
When it is determined that the decompression operation of the compressed data decompression unit 8 cannot catch up with the printing operation of the printing mechanism unit 9, the control signal C is output to the switch 20 to connect the frame buffer 4 and the hard disk 30. To be As a result, when the data corresponding to the band near the top of the page is written in the frame buffer 4, the bitmap image data D2 is read out and stored in the hard disk 30 via the switch 20.

The drawing and storing processes are repeated in sequence, and 1
When the bitmap image data D2 for one page is stored in the hard disk 30, the bitmap image data D2 for one page is read from the hard disk 30 and printed by the printing mechanism unit 9 at once.

As described above, in the present embodiment, the compression rate of the data compression section 6 cannot sufficiently cope with it, and the decompression operation of the compressed data decompression section 8 cannot catch up with the printing operation of the printing mechanism section 9. Even when the print data D1 having such contents is input, the printing operation can be normally performed. The rest of the configuration, functions and effects are the same as those of the first embodiment, so description thereof is omitted.

[0054]

As described above, according to the electrophotographic page printer of the present invention, when the expansion of the print data is the expansion of the outline font or the complicated graphic data, or the expansion of a large amount of data per page. If
The control unit determines that the required expansion time is out of the specified time, and the compression / decompression means sequentially compresses and stores the data, and the decompressed one page of bitmap image data is printed. Therefore, the so-called "overrun" phenomenon occurs. Does not happen. As a result, the present invention exhibits an excellent effect that the printing accuracy can be improved.

Further, since the frame buffer is set to a small capacity sufficient to store the bit map image data of a fraction of one page, the memory can be saved, and as a result, the cost of the apparatus can be reduced. The effect is that you can.

Further, by providing a hard disk capable of storing at least one page of bitmap image data, the compression rate of the compression / decompression means is insufficient, and the decompression operation cannot catch up with the printing operation of the printing mechanism section. There is an effect that print data having such contents can be printed.

[Brief description of drawings]

FIG. 1 is a block diagram showing an electrophotographic page printer according to a first embodiment of the present invention.

FIG. 2 is an operation flow chart of the first embodiment.

FIG. 3 is a block diagram showing an electrophotographic page printer according to a second embodiment of the present invention.

[Explanation of symbols]

 1 page data buffer 2 control unit 3 decompression mechanism unit 4 frame buffer 5 switcher 6 data compression unit 7 compressed data buffer 8 compressed data decompression unit

Claims (4)

[Claims] 1. A page data buffer for storing print data for one page in a code state, an expansion mechanism unit for expanding and generating bitmap image data from the print data in the page data buffer, and the expansion mechanism unit. A frame buffer capable of storing bitmap image data that is a fraction of one page out of the generated bitmap image data, and the bitmap image data of this frame buffer are sequentially compressed and stored, and compressed data for one page Based on the print data in the page data buffer, and
A control unit that determines whether the required expansion time in the expansion mechanism unit is within a specified time, and the bitmap image data in the frame buffer when the expansion unit determines that the required expansion time is within the specified time. And a printing mechanism that prints one page of bitmap image data decompressed by the compression / decompression means when it is determined that the required expansion time is outside the specified time. A featured electrophotographic page printer. 2. A compression / decompression means for compressing bitmap image data in the frame buffer, a compression data buffer for sequentially storing compression data formed by the data compression unit, and the compression unit. The electrophotographic page printer according to claim 1, further comprising a compressed data decompression unit that decompresses the compressed data for one page in the data buffer into the original bitmap image data. 3. A hard disk capable of storing at least one page of bitmap image data of the frame buffer, wherein the control unit requires expansion in the expansion mechanism unit based on print data in the page data buffer. In addition to determining whether the time is within a specified time, it is further determined whether or not the compression ratio in the compression / decompression means and the decompression operation are performed when it is determined that the necessary expansion time is outside the specified time. Yes, the printing mechanism unit, in the control unit, sequentially prints the bitmap image data of the frame buffer when it is determined that the required development time is within the specified time,
In addition, the expansion required time is outside the specified time and the compression /
When it is determined that the compression ratio and the decompression operation in the decompression means are correct, one page of bitmap image data decompressed by the compression / decompression means is printed, and the decompression time is outside the specified time. 3. The one-page bitmap image data in the hard disk is printed when it is determined that the compression rate or the decompression operation in the compression / decompression means is non-conforming.
The described electrophotographic page printer. 4. A selection means for guiding bit map image data in the frame buffer to any one of the printing mechanism section, compression / decompression means, and hard disk based on the judgment of the control section. An electrophotographic page printer according to claim 3.