JPH1058766A - Image data output control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a continuous output following continuous printing by a printer and facilitate error recovery even, if a main storage device has a small capacity. SOLUTION: A raster image generating means 31 generates raster image data from PDL and supplies to a main storage control means 32. The main storage control means 32 converts virtual addresses into physical addresses in accordance with information in an address conversion table 34 by means of an address conversion means 33 and stores raster image data developed in accordance with the physical addresses by prescribed blocks. At that time, when empty blocks cease to exist in a main storage 35, data are retreated to a secondary storage 37, releasing the blocks. A data transfer means 38, when development ends for one page's data, transmits raster image data returned to the main storage 35 from the secondary storage 37 in sequence block by block to an output device 40. The conversion table modification means 39, when transfer to the output device 40 ends, resets paging prohibition attributes of the address conversion table 34 block by block for releasing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a document processing system, and more particularly to an image data output control device for storing generated images and transferring / outputting the generated images to a printer.

[0002]

2. Description of the Related Art In recent years, with the development of information processing apparatuses, high-speed, high-quality images have been required for printers located in peripheral devices thereof. As a printing device for satisfying these requirements, an electrophotographic process printer using a laser has already been put into practical use. In recent years, 600 DPI and 135 pages / min in monochrome, and also in color, 400 DPI, full color 40 pages /
High-quality and high-speed printers such as minutes have also appeared. In these output devices, in order to perform high-speed output, a plurality of sheets are continuously conveyed to the output unit, and printing is sequentially performed.

In the above-described printer, when a document including a plurality of pages is continuously output, if a printer error such as a paper jam occurs during output, raster image data of the page in which the error occurred is lost. For this reason, it is necessary to request the host to retransmit the same page. If the host cannot respond, the printing operation in the printer is stopped in the worst case.

Therefore, conventionally, a raster image to be output to a printer is generated from printer data from a host, and raster image data of a plurality of pages is temporarily expanded in a main storage device such as a DRAM and then output to a printer. Data output control devices are known. In the image data output control device, images of a plurality of pages output to the printer are stored as raster image data, and when a printer error occurs, the raster image data of the page in which the error occurred is output to the printer again. This eliminates the need to re-develop the same page into a raster image. Therefore, the storage device of the output data output control device holds the raster image data of the page sent to the printer until it is completely output by the printer, and is released after the corresponding page is completely discharged.

As described above, the image data output control device described above requires a storage area for a plurality of pages. However, in order to store image data for one page, about 2 Mbytes are required for an A4 size 400 DPI, monochrome, binary image. In addition, full color (YM
CK, each component is expressed in 8-bit gradation), the data amount is as large as 64 Mbytes, and even if a storage area for one page is provided as well as a plurality of pages, it is realized in consideration of cost. There is a problem that is difficult.

Therefore, in order to avoid the above-mentioned problem,
For example, as disclosed in Japanese Patent Application Laid-Open No. 4-301478, a method / apparatus has been proposed in which raster image data is stored in a secondary storage device such as a hard disk whose bit unit price is lower than that of a DRAM and is output to a printer. .

[0007]

By the way, the output to the printer is, for example, relatively low speed 10 PPM, 400 D
16 MB / PI, full color printer
Requires bandwidth on the order of seconds. However, since the conventional image data output control device uses a secondary storage device having a lower transfer speed than the primary storage device (semiconductor memory), it uses DMA (Direct Memory Access).
It is necessary to output directly from the primary storage device (semiconductor memory: RAM). Therefore, in a conventional image data output control device, at least a primary storage device (semiconductor memory: R) for storing at least one page of raster image data.
AM). Also,
Since each process of image generation, storage, and output can only be performed sequentially, there is a problem that a great deal of time is required for output.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances. Even in a main storage device having a small storage capacity, an image can be continuously output following continuous printing by a printing device and error recovery can be easily performed. It is an object to provide a data output control device.

[0009]

In order to solve the above-mentioned problems, the present invention provides an input means for inputting a page description language, interprets the page description language input by the input means, and converts image data. Image generating means for generating;
A main storage unit that is divided into a plurality of regions and stores the image data generated by the image generation unit in units of the region, and a secondary storage unit that temporarily saves the image data stored in the main storage unit When there is no more usable area in the main storage means, a saving means for saving a part of the image data already stored in the main storage apparatus to the secondary storage apparatus and changing a corresponding area to an available area; When the generation of one page of image data is completed by the image generation means,
When a part of the image data of the page is saved in the secondary storage means, the saved image data is sequentially transferred from the top to the usable area of the main storage means, and the corresponding area cannot be used. And a transfer unit for transferring the image data stored in the main storage unit to the output device in order from the top and changing the area after the transfer to a usable area. And

According to the present invention, the image generating means interprets the page description language input by the input means and generates image data. The image data is stored in the main storage unit for each divided area. Here, when the available area is exhausted in the main storage unit, the saving unit saves a part of the image data already stored in the main storage device to the secondary storage device and changes the corresponding area to the available area. I do. And
When the generation of the image data for one page is completed, the restoring unit, when a part of the image data of the page is saved in the secondary storage unit, sequentially stores the saved image data in the main storage from the top. Transfer to the usable area of the means and change the corresponding area to the unusable area. Further, the transfer means transfers the image data stored in the main storage means to the output device in order from the top, and changes the area after the transfer to a usable area. Therefore, even if the main storage device has a small storage capacity, continuous output can be performed following continuous printing by the output device.

In addition, since all image data generated by the image generation means is held in the main storage means or the secondary storage means regardless of whether or not the data has already been output to the output device, the image data is not transferred by the transfer means. Even if an error occurs in the output device, the restoring unit sets the entire area of the main storage unit as an available area, and stores the image data after the page where the error occurred in the available area of the main storage unit in order from the secondary storage unit. After the transfer, the corresponding area is changed to an unusable area, and the image data stored in the main storage means is again transferred from the top to the output device by the transfer means, and the generation of the image data is executed again. This eliminates the necessity and facilitates error recovery.

[0012]

Embodiments of the present invention will now be described with reference to the drawings.

A. Configuration of Embodiment A-1. Document Processing System First, a document processing system using the image data output control device according to the present embodiment will be described. Here, FIG. 3 is a block diagram showing a configuration example of the document processing system. In the figure, a host computer 1 converts a created document composed of a figure, a bitmap image, a character, and the like into a page description language (PDL) at the time of printout, and then converts the document to an Ethernet (Small Computer).
The image data is transmitted to the image data output control device 2 via a communication line such as a system interface or a serial. The image data output control device 2 includes an input interface 3, a language interpretation / image processing unit (raster image processing: RIP) 4,
A frame buffer 5 and an output interface 6 are provided. The input interface 3 inputs data from the host computer 1 and converts the input data into
After temporarily storing it in an input buffer in the interface, it is supplied to the language interpretation / image processing unit 4. The language interpretation / image processing unit 4 interprets the PDL, generates raster image data (bitmap data), and supplies it to the frame buffer 5. The frame buffer 5 has a logical space of several gigabytes, for example, and stores raster image data for a plurality of pages. Specifically, for example, it is composed of a main storage device (physical space) of 16 Mbytes and an external storage device (physical space) of several Gbytes. to access. In addition, rasterization of raster image data and output to a printer as an output device are always performed only in the main storage device. In other words, the entire system is controlled as if the raster image data for a plurality of pages is stored in the main storage device. The output interface 6 outputs the raster image data developed in the frame buffer 5 to an output device (image output terminal: printer) 7 for each page.

A-2. Configuration of Image Data Output Control Device Next, the configuration of the above-described image data output control device will be described. FIG. 4 is a block diagram showing a configuration of the image data output control device 2. Address bus and control bus 1
0, a data bus 11, and an interrupt control signal 12 are signal lines for exchanging data between a CPU 22 described later and each interface described later. Interrupt control signal 1
Reference numeral 2 denotes a signal for notifying the CPU 22 of various events generated from each interface or device. The input / output interface 13 is an interface for inputting a PDL generated by a client computer. In the present embodiment, the input / output interface 13 is a LAN (Local Area Network) such as an Ethernet or a serial line.
k) It assumes an interface in the environment.

The SCSI interface 14 controls input and output of data to and from the hard disk device 15. The hard disk device 15 has a storage capacity of, for example, about several gigabytes. The address translation device 16 includes a memory management unit 17 and an address translation table 18. The memory management unit 17 uses the information of the address conversion table 18 to convert the virtual address supplied from the CPU 22 via the address bus into a D
The data is converted into a physical address for accessing a RAM (Dynamic Random Access Memory) 20 and supplied to the DRAM controller 19. The address conversion table 18
Will be described later in detail.

The DRAM controller 19 accesses the DRAM 20 according to the physical address. DRA
As described above, M has, for example, a storage capacity of about 16 Mbytes (1/4 of a normal size), is divided into a plurality of blocks in units of a fixed length area, and one block is formed as one block of 32 Kbytes. , 512 blocks. Basically, the raster image data is stored in the DRAM 2
However, when there is no free space in the DRAM 20, the data is transferred to the hard disk device 15. The DMA interface 21 outputs the raster image data developed in the virtual space (actually, DRAM) to the printer 23 which is an output device without passing through the CPU 22. This allows
Data to the printer 23 can be directly transferred from the DRAM 20 by the DMA method. The DMA interface 21 has a function of accessing the address conversion table 18, and rewrites information in the address conversion table 18 to store raster image data output to the printer 23 as an output device. (DRAM 20) can be released.
The details of this function will be described later.

A-3. Next, a description will be given of a data flow and a control flow (function) of the image data output control device described above.
Here, FIG. 1 is a block diagram showing a functional configuration of the image data output control device according to the embodiment of the present invention. In the figure, a data input unit 30 corresponds to the input / output interface 13 in FIG. 4 and inputs a PDL generated by a client computer. Raster image generating means 31
Corresponds to one function (program) of the CPU 22 of FIG. 4 or the language interpretation / image processing unit 4 shown in FIG. 3, interprets the PDL input from the data input unit 30, generates raster image data, and stores It is supplied to the management means 32. The main storage management means 32 corresponds to the address translation device 16 in FIG. 4, and the address translation means (corresponding to the memory management unit 17 in FIG. 4) 33 controls the memory area for storing the raster image data (in units of one page). The virtual address is converted into a physical address of the main storage device 35 in accordance with the information in the address conversion table (corresponding to the address conversion table 18 in FIG. 4) 34, and the physical address
5 is accessed, and the developed raster image data is stored.

As shown in FIG. 2, the address translation table 34 has a valid flag indicating whether the PTE (page table entry) of the address translation table 34 is valid for each divided block of the main storage device 35. (Attribute information) 34a, a paging prohibition attribute 34b indicating whether or not paging is possible (accessible), and a physical page number 34c indicating the location of the physical memory corresponding to the virtual address
Consists of When the virtual address cannot be converted into the physical address, in other words, when the main storage device runs out of free space, the main storage management unit 32 controls the input / output control unit (the SCSI interface in FIG. 4) by controlling The secondary storage device 37 is accessed, and the raster image data in the main storage device 35 is transferred to the secondary storage device 37.

The main storage device 35 corresponds to the DRAM 20 shown in FIG. 4 and has a storage capacity of 16 Mbytes, as described above, and is stored in a predetermined block unit (for example, 32 Kbytes).
When the raster image data at the time of DL development is stored and the raster image data is output to the output device 40, the raster image data of the predetermined page held in the secondary storage device 37 is stored in a free area (release area). It is transferred in units. Next, the secondary storage device 37
When the raster image data is stored exceeding the capacity of the main storage device 35 and corresponds to the hard disk device 15 in FIG. 4, the raster image data already expanded and stored in the main storage device 35 is transferred in block units. You. The data transfer means 38 corresponds to the DMA interface 21 of FIG. 4, reads out the raster image data which has been developed in a predetermined block unit (for example, 4 Kbytes or 8 Kbytes) and sends it to the output device 40. At this time, the data transfer means 38 transfers the raster image data stored in the main storage device 35.

That is, when the raster image data to be output is not in the main storage device 35, in other words, when the raster image data to be output is evacuated to the secondary storage device 37, The raster image data in the next storage device 37 is sequentially transferred in units of predetermined blocks (released blocks) in the main storage device 35. At this time, the main storage device 3
If there is no empty block in 5, the process waits. Further, when the raster image data is transferred to the output device 40, the data transfer unit 38 causes the conversion table changing unit 39 to release the block in which the raster image data is stored. Reset.

A-4. Functional Configuration of Memory Management Unit Next, FIG. 5 is a conceptual diagram showing a functional configuration (operation) of the address translation device according to the above embodiment. In the figure, a virtual address 50 is supplied from the CPU 22 or the printer interface described above, and a PTE (Page Table Entry) of the address translation table 18.
(Lower 16 bits) indicating the PTE number (upper 17 bits) indicating the lower 16 bits of the physical address
Bit) 52.

The address conversion table 18 is stored in the CPU 22
The attribute 53 and the high-order 17 bits 54 of the physical address are stored for each PTE number 51 (0000-1ffff) of the virtual address 50. Although the configuration of the address conversion table 18 has been described above, in more detail, as shown in FIG. 6, a valid flag (1 bit) 55 indicating whether the PTE is valid and indicating whether paging is possible. Paging prohibited attribute (1 bit) 56, access attribute (3 bits)
57, an unused area (10 bits) 58 and a physical page number (15 bits) 59. When the output of the raster image data of the block indicated by the corresponding physical address to the printer 23 is completed, the DMA interface 21 (data transfer means 38) resets the paging inhibition attribute 56,
Release the corresponding block. Further, as shown in FIG. 7, the physical page number 54 in the PTE indicates a block number obtained by dividing the DRAM 20 (main storage device 35) having a continuous storage area into fixed-length area units. . In the present embodiment, as described above, one block has an area of 32 Kbytes and 512 blocks.

B. Next, an operation of the image data output control device according to the present embodiment will be described. Here, FIGS. 8 to 10 and FIG.
5 is a flowchart for explaining the operation of the image data output control device. FIG. 11 is a timing chart for explaining the entire operation sequence of the expansion processing and the output processing. FIG. 12 is a conceptual diagram for explaining a process of returning from interruption due to a paper jam or the like in the middle of output of a printer as an output device.

B-1. Image Expansion and Output Processing Next, image expansion and output processing will be described with reference to FIG. In step Sa1 of FIG. 8, first, the address conversion table is initialized. This initialization is performed by setting all the PTEs in the address conversion table. At this time, the paging prohibition attribute of each PTE is reset, and the raster image data in those areas is permitted to be transferred (evacuated) to the hard disk as the secondary storage device as necessary.

Next, in step Sa2, the PDL, which is graphic description data, is read out, and in step Sa3, the PD
L is sequentially interpreted and expanded into a physical address of a physical memory (DRAM) obtained from a virtual address in an address conversion process described later. At this time, the raster image data is developed in block units (32 Kbytes) of the physical memory described above. If an attempt is made to access a virtual area to which no physical memory has been allocated during the development, an interrupt is generated from the memory management unit 17 to the CPU 22 in the address conversion processing described later. In this case, development to raster image data is waited until an assignable block is obtained in the physical memory. On the other hand, when the blocks that can be allocated are secured, expansion is continued for the secured physical memory blocks.

Also, during the development, the physical memory becomes insufficient,
Even when the free area is exhausted, the memory management unit 17 sends the C
An interrupt occurs to the PU 22. In this case, rasterization to raster image data is waited until a block in use in the physical memory is released, for example, by transferring the data to the hard disk device 15 as a secondary storage device in block units. On the other hand, when the block in use is released, the expansion of the released block of the physical memory is continued.

Next, in step Sa4, it is determined whether or not the development of one page has been completed. If not completed, steps Sa2 and Sa3 described above are repeatedly executed. When the rasterization of one page is completed, the raster image data for the page is transferred to the printer 23 as an output device by DMA transfer. The unit is saved in the hard disk device 15. Therefore, prior to the output, in step Sa5, the saved raster image data is read out one word at a time from the beginning for every 32 Kbytes of a physical page, which is a unit of division in the PTE, and stored in a predetermined block on the DRAM 20 as a physical memory. return. Further, in order to assure that the raster image data of the returned block is not paged during the output (processing for saving to the hard disk as the secondary storage device),
Perform page lock processing. This page lock processing is performed by returning the raster image data from the beginning to the physical memory, and then setting the paging prohibition attribute of the PTE of the address conversion table corresponding to the raster image data.

Further, the DRA from the hard disk device 15
When returning to M20, if the physical memory is insufficient and there is no free space, the memory management unit 17 interrupts the CPU 22 in the address conversion process described later, as described above. Therefore, in the case of the processing of the first page, the physical memory D
In the RAM 20, the developed block is transferred to the hard disk device 15 as a secondary storage device until the developed block is released, in other words, the block is waited for being released. In the case of the processing for the second and subsequent pages, in addition to the release of the block, the D
The transfer to the printer 23, which is an output device, by the MA interface 21 is completed, and the process waits until the block is released.

Next, in step Sa6, the DMA interface 21 is activated, and the DMA interface 21 is started.
Thus, the raster image data returned to the DRAM 20 as the physical page is sequentially output to the printer 23. The D
The MA interface 21 can queue a plurality of transfer start commands, and when the transfer to the printer 23 is completed, the DMA interface 21 resets the paging inhibition attribute of the PTE of the address translation table 18 for the block. I do. As a result, the block becomes a target of paging, so that the block can be reused. The raster image data saved in the hard disk device 15 can be returned to the block or the raster image data of the next page can be transferred to the block. Used to expand. Next, in step Sa7, it is determined whether the output of the raster image data for one page is completed,
If not completed, the process returns to step Sa5, and steps Sa5 to Sa6 are repeatedly executed for the same page. When the output of the raster image data for one page is completed, the process proceeds to step Sa8, and it is determined whether the output of the raster image data for all pages is completed.
If not, the process returns to step Sa2, and the above-described steps Sa2 to Sa6 are repeatedly executed. When the output of all pages is completed, the process ends.

B-2. Address Conversion Process Next, an address conversion process for converting a virtual address to a physical address in the above-described expansion process and output process will be described with reference to FIG. Step Sb1 in FIG.
Divides the 32-bit virtual address supplied from the CPU 22 into upper 17 bits and lower 15 bits,
Generate a PTE address with the upper 17 bits. Next, in step Sb2, the address conversion table 18 is accessed using the upper 17 bits (PTE address), and one PTE corresponding to the virtual address is extracted. Step S
In b3, it is determined whether the valid flag of the PTE is “false”. If the valid flag is “false”, there is no physical address for the virtual address. In other words, the physical address number is stored in the PTE. Since it has not been assigned, the process proceeds to step Sb5, where the CPU 22 is notified by generating an interrupt. When an interrupt occurs, the CPU 22 executes a paging interrupt process described later to secure a block to which a physical address can be assigned to the virtual address. However, if there is no block that can be allocated, development to raster image data is waited until it can be secured.

On the other hand, if the validity flag is true, the flow advances to step Sb4 to determine whether or not the access attribute of the PTE is "false". If the access attribute is "false", that is, for some reason, If the block of the physical address corresponding to the virtual address cannot be accessed, the process proceeds to step Sb5, and the CPU 22 is notified by generating an interrupt. The CPU 22
By the same processing as described above, a block to which a physical address for the virtual address can be allocated is secured. However, if there is no block that can be allocated, development to raster image data is waited until it can be secured.

If the valid flag and the access attribute are both true, the process proceeds to step Sb6, where the PTE
After the physical address PA corresponding to the virtual address is generated from the physical page number and the lower 15 bits of the virtual address, the process ends.

B-3. Paging Processing Next, paging processing executed by an interrupt in the above-described address conversion processing will be described with reference to FIG. First, in step Sc1 of FIG.
It is determined whether or not there is a block that can be assigned to the virtual address at 20. If there is a block that can be assigned, the process proceeds to step Sc4, where the address conversion table 18
Then, the physical address number of the block is set in the corresponding PTE, and the process ends.

On the other hand, if there is no block that can be allocated, the flow advances to step Sc2 to determine whether the raster image data is a block that can be expelled to the hard disk device 15 as a secondary storage device. Is searched for by checking the paging prohibition attribute of the corresponding PTE in the address conversion table 15. And
If there is a block that can be evicted, the process proceeds to step Sc3, where the raster image data of the block is saved in the hard disk device 15 as a secondary storage device, and in step Sc4, the corresponding PT in the address conversion table 18 is stored.
The block is set to E, and the process ends.

On the other hand, if there are no allocatable blocks or no eviction blocks, step Sc2 is repeatedly executed until an eviction block occurs. Therefore, as described above, rasterization to raster image data or DMA interface Printer 2 by 21
The process of returning to the DRAM 20 prior to the transfer to No. 3 is in a standby state.

B-4. Operation Sequence Next, an overall flow of the above-described expansion processing and output processing will be described with reference to FIG. First, in response to a request from the main thread, the PDL of the first page is input (S
Q1), it is developed into raster image data (SQ2). At this time, if there is no empty block, the raster image data already developed is saved in the hard disk device 15 and
The block can be used by resetting the paging prohibition attribute corresponding to the block. Therefore, the development into the raster image data is performed continuously. When the development of one page is completed, the developed raster image data is returned from the hard disk device 15 to the DRAM 20 in block units before being output to the printer 23, and paging is prohibited for the block. After that (SQ3), the DMA interface 21 is activated (SQ4). The DMA interface 21 synchronizes with the paging signal output from the printer 23 as an output device (SQ5), and converts the raster image data of the first page returned to the DRAM 20 into a predetermined block unit (2 Kbytes or 4 Kbytes). To start output (SQ6). On the other hand, the main thread executes 1
Subsequent to the development of the page, the PDL of the second page is input and developed into raster image data (SQ7,
SQ8).

At this time, if there are no more empty blocks in the DRAM 20, the DRAM 20 enters a paging waiting state (SQ9). When the DMA transfer of the first page proceeds, the DRAM
Since 20 is released in block units, as a result, paging processing is executed (SQ10), and the paging inhibition attribute of the corresponding PTE in the address translation table 18 is reset (SQ11). As a result, the expansion processing that has been in the waiting state is restarted (SQ12). By repeating such a series of operations, the main storage device DR
Even if the storage capacity of the AM 18 is at least and the hard disk device 15 as a secondary storage device is used as a save area for raster image data, continuous output can be performed following continuous printing by the printer 23 as an output device.

B-5. Error Recovery Process Next, a process of recovering from an interruption due to a paper jam or the like during output of a printer as an output device will be described with reference to FIGS. First, in FIG.
In the document of the page, the rasterization processing to the raster image data has already been completed for the first to fifth pages. Of these, two pages of the first and second pages are normally printed out, and the fourth page is output. Caused by a paper jam
This indicates that the third and subsequent pages were not output normally. According to the above-described embodiment, the image data output control device stores all the expanded pages in the document in the virtual space regardless of whether the output has been performed to the printer 23 as the output device. Therefore, only the initialization and restart of the PTE of the address conversion table 18 need to be performed after the paper jam is cleared.

That is, in step Sd 1 of FIG. 13, first, the paging inhibition attributes in all the PTEs of the address translation table 18 are reset. Next, step Sd2
Page where normal output was not obtained (page 3)
Thereafter, the raster image data saved in the hard disk device 15 is sequentially returned to the DRAM 20 in block units, and the paging inhibition attribute in the PTE of the address conversion table 18 for those blocks is set again and locked. Then, in step Sd3,
For pages after which normal output was not obtained, DM
The A interface 21 is activated, and DMA transfer is performed from the third page to the printer 23 as an output device.

For a block for which DMA transfer to the printer 23 has been completed by the DMA interface 21, the paging inhibition attribute in the PTE of the address conversion table 18 of the block is reset and released. Next, in step Sd4, it is determined whether or not output for one page has been completed.
Returning to d2, steps Sd2 and Sd3 are repeatedly executed. When the output of the raster image data for one page is completed, the process proceeds to step Sd4, where it is determined whether or not the DMA transfer has been performed for all the pages for which the output has not been completed. If the interface 21 has not been activated, steps Sd2 to Sd4
Are repeatedly executed, so that the fourth page, the fifth page,
The raster image data of the page is DMA-transferred to the printer 23 as an output device. Therefore, the printer 23 as an output device prints again from the third page onward. When the DMA transfer for all the pages for which the output has not been completed is completed, the process ends, and the process returns to the above-described expansion process and output process.

[0041]

As described above, according to the present invention, the image generating means interprets the page description language input from the input means, generates image data, and divides the image data into divided areas. When storing in the main storage unit in units,
When the usable area in the main storage unit is exhausted, the saving unit saves a part of the image data already stored in the main storage device to the secondary storage device, and sets the corresponding area as the usable area. When the generation of the image data is continued and the generation of the image data for one page is completed, if the image data is saved in the secondary storage unit by the return unit,
The image data of the evacuated page is sequentially transferred from the top to the usable area of the main storage means, locked by changing the corresponding area to an unusable area, and further stored in the main storage means by the transfer means. The transferred image data is transferred to the output device in order from the top, and the area after the transfer is changed to the usable area. Therefore, even if the main storage device has a small storage capacity, it can be used for continuous printing of the output device. There is an advantage that continuous output can be performed following the output.

Further, according to the present invention, all image data generated by the image generating means is held in the main storage means or the secondary storage means, regardless of whether or not the image data has already been output to the output device. Even if an error occurs in the output device during the transfer by the transfer means, the entire area of the main storage means is set as the usable area by the return means, and the image data after the page in which the error occurred is sequentially stored in the main storage means from the secondary storage means. After the transfer to the usable area of the apparatus, the corresponding area was changed to the unusable area, and the transfer means transferred the image data stored in the main storage means to the output device again in order from the beginning. In addition, there is no need to execute image data generation again, and the advantage that error recovery can be easily performed can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a functional configuration of an image data output control device according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram showing a configuration of an address conversion table.

FIG. 3 is a block diagram illustrating a configuration example of a document processing system.

FIG. 4 is a block diagram illustrating a configuration of an image data output control device.

FIG. 5 is a conceptual diagram showing a functional configuration (operation) of a memory management unit.

FIG. 6 is a conceptual diagram showing a more detailed configuration of an address conversion table.

FIG. 7 is a conceptual diagram showing a configuration of a block of a DRAM.

FIG. 8 is a flowchart for explaining an expansion process and an output process.

FIG. 9 is a flowchart illustrating an address conversion process.

FIG. 10 is a flowchart illustrating a paging process.

FIG. 11 is a timing chart for explaining the entire operation sequence of the expansion processing and the output processing.

FIG. 12 is a conceptual diagram for describing a process of recovering from interruption due to a paper jam or the like during output of a printer as an output device.

FIG. 13 is a flowchart illustrating a process of returning from interruption due to a paper jam or the like during output of a printer serving as an output device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 13 Input interface (input means) 15 Hard disk drive (secondary storage means) 16 Address conversion apparatus (save means, return means, address conversion means) 18 Address conversion table 20 DRAM (main storage means) 21 DMA interface (transfer means) 22 CPU (Image generating means, saving means, returning means) 23 Printer

Claims (5)

[Claims] An input unit for inputting a page description language; an image generation unit for interpreting the page description language input by the input unit to generate image data; and an image generation unit divided into a plurality of areas. Main storage means for storing the image data generated by the area unit, a secondary storage means for temporarily saving the image data stored in the main storage means, and no usable area in the main storage means Saving means for saving part of the image data already stored in the main storage device to the secondary storage device and changing the corresponding area to a usable area; and image data for one page by the image generating means. Is completed, when a part of the image data of the page is saved in the secondary storage means, the saved image data is sequentially used from the main storage means from the top. Transfer means for transferring the image data stored in the main storage means to the output device sequentially from the top to the output device, and transferring the image data stored in the main storage means to the usable area. An image data output control device, comprising: 2. An apparatus according to claim 1, further comprising address conversion means for converting a logical address for storing said image data, provided from said image generation means, into physical addresses corresponding to a plurality of areas of said main storage means. Claim 1
The image data output control device described in the above. 3. The method according to claim 2, wherein the address conversion unit assigns a paging prohibition attribute indicating whether the area is an available area or an unusable area to each of the plurality of areas. 3. The image data output control device according to claim 2, wherein by changing the paging prohibition attribute, the corresponding area is enabled or disabled. 4. The apparatus according to claim 1, wherein said address conversion means comprises:
An address conversion table having the physical address corresponding to the logical address, and a paging inhibition attribute indicating whether an area of the main storage unit indicated by the physical address is an available area or an unusable area; 3. The image data output control device according to claim 2, wherein said means comprises a conversion table changing means for changing a paging inhibition attribute of said address conversion table. 5. When an error occurs in the output device during the transfer by the transfer unit, the return unit sets the entire area of the main storage unit as a usable area, and stores the image data after the page in which the error has occurred. After sequentially transferring from the secondary storage means to the usable area of the main storage device, the corresponding area is changed to an unusable area, and the transfer means re-starts the image data stored in the main storage means again. 2. The image data output control device according to claim 1, wherein the image data is sequentially transferred to an output device from the first device, and the area after the completion of the transfer is changed to a usable area.