JPH10309835A - Page printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a work of copying to a band buffer when a preliminary development image is printed and efficiently carry out a printing process in a page printer. SOLUTION: A processor 1 divides one page to a plurality of bands, and registers an intermediate code 73 of each band to a printing position management table 7. When a printing engine 13 starts to print each band, the processor lends an image of the band to a band buffer 9 and transfers the image in the band buffer 9 to the printing engine 13 in a DMA. However, if a volume of the intermediate code of the band is considerably large, the processor 1 lends the image of the band to an external band buffer 11 beforehand. A print state management tug 91 is provided at the general band buffer 9, and a similar tug 111 is set to the external band buffer 11 as well.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to the handling of band image buffers in page printers.

[0002]

2. Description of the Related Art In a page printer, as shown in FIG.
Is divided into unit blocks 103 called “bands”, and in order to improve the memory efficiency, the image of each band 103 is converted into an intermediate code 105 and stored in the memory. When the intermediate code 107 of the image for one page is completed, the print engine is operated (printing is started). During the operation of the engine, the intermediate code 1 of each band is synchronized with the operation of the engine.
05 is rendered to the band buffer 109 (that is,
Image). The image developed in the band buffer 109 is transferred to the print engine by DMA. Note that the number of the band buffers 109 is fixed in advance to a minimum number within a range where rendering cannot be completed in time for transfer to the print engine (this is called “overrun”).

However, when a situation is detected in which the amount of intermediate codes in a certain band is likely to increase and an overrun is likely to occur,
Alternatively, upon detecting a situation in which the intermediate code is larger than the rendered image, the processor renders the image of the band to a location 111 different from the band buffer 109 in advance without synchronizing with the engine ( This is called "pre-deployment.") And
When printing the band, the pre-deployed image is copied from the storage location 111 to the band buffer 109.

[0004]

As described above, in the conventional page printer, when the pre-developed image is transferred to the engine, the image is copied from the storage location 111 to the band buffer 109, and then is transferred to the band buffer 109. To the engine. The reason is that the image in the band buffer 109 is cleared for rendering of the subsequent band after the transfer to the engine, whereas the pre-deployed image in the storage location 111 has an error such as a paper jam after the engine is transferred. This is because it is necessary to hold the data so that it can be printed again when it occurs.

However, copying a pre-deployed image from its storage location to a band buffer is a wasteful task and inefficient in rendering subsequent bands to the band buffer.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to eliminate the task of copying a pre-developed image to a band buffer in a page printer.

It is another object of the present invention to streamline rendering and transfer of band images to a print engine.

[0008]

SUMMARY OF THE INVENTION A page printer according to a first aspect of the present invention reserves in memory a memory, a print engine, and a normal band buffer for rendering a normal band image during printing. Means for securing an external band buffer in memory for pre-rendering the image of the pre-development band, and directing the image in the normal band buffer and the image in the external band buffer directly to the print engine at the time of printing. Transfer means for transferring, and after each transfer, clearing only the image in the normal band buffer in preparation for rendering the image of the next band.

A page printer according to a second aspect of the present invention comprises a memory, a print engine, means for securing each band buffer for rendering an image of each band in the memory, and an image in each band buffer. Transfer means for directly transferring to the print engine at the time of printing, the transfer means distinguishing whether the image in each band buffer is of a normal band or a pre-development band, and after each transfer, Only the normal band image in each band buffer is cleared in preparation for rendering the next band image.

In these page printers of the present invention, both the image of the pre-expanded band and the image of the normal band which has not been pre-expanded are directly transferred from the rendered band buffer (that is, transferred to another band buffer). Forwarded to the print engine (without going through a copy). Then, after transfer to the print engine, only the normal band image in the band buffer is cleared in preparation for rendering the next band image, and the pre-development band image needs to be reprinted later for error recovery Is held without being cleared in case of occurrence of.

In the present invention, the storage location of the image of the normal band (normal band buffer) and the storage location of the image of the pre-development band (external band buffer) are handled in the same manner with respect to the transfer to the print engine. For clearing after transfer, the normal band buffer and the external band buffer are handled differently. As one means for enabling such handling, a print state management tag can be provided in each band buffer. This tag indicates the identification number of each band buffer and the printing state. Here, the “print state” is a progress state of band buffer processing related to printing, for example, whether or not rendering has been completed and whether or not transfer to the engine has been completed. By using this print state management tag, it is possible to transfer images directly from the external band buffer to the engine in the same way as a normal band buffer, and to distinguish between the external band buffer and the normal band buffer. , Can be handled differently for clearing after transfer.

In the page printer of the present invention, preferably, there can be provided means for generating null data at the time of printing a null band (that is, a blank band having no image to be printed) and supplying the null data directly to the print engine. This eliminates the need to use a band buffer in memory for null bands, thus improving memory utilization and allowing band image rendering and transfer processes to be performed more efficiently.

[0013]

FIG. 2 shows a configuration of a main part of a page printer according to an embodiment of the present invention.

The processor 1 secures a reception buffer 5, a print position management table 7, and a normal band buffer (hereinafter simply referred to as "band buffer") 9 in the memory 3. The processor 1 also secures the external band buffer 11 in the memory 3 as needed.

The reception buffer 5 is a place for temporarily storing print commands received from the host computer. The print position management table 7 is used to manage the print position of each band and is a place where the intermediate code of each band is stored. In the printing position management table 7 in the figure, each line separated by a horizontal line indicates an area assigned to each band, and in each band area,
The numeral 71 in the left field indicates the printing order of each band on the paper, and the right field indicates the storage location (intermediate code buffer) of the intermediate code of each band. Here, a band in which “NULL” is written in the field on the right side means that printing is not performed on the band (being blank on paper) (the band is referred to as a “null band”). .

The band buffer 9 is a place where the image of each band rendered in synchronization with the operation of the print engine 13 is temporarily stored. In the band buffer 9 in the figure, each row separated by a horizontal line indicates an area assigned to each band. Each band area has a “print state management tag” for indicating the print state of each band image.
Has a portion 91 called a. Print status management tag 9
A field 93 shown on the right side of 1 indicates a storage location of an image of each band. The size of the band buffer 9 should be within the range normally expected without overrun,
Only the minimum number of bands (four bands in the illustrated example) is secured.

The external band buffer 11 is a place for storing an image of a pre-developed band, and is reserved for a band when the pre-deployment of the band becomes necessary. The external band buffer 11, like the band buffer 9, has a “print state management tag” 111 for indicating the print state of the band image. Field 11 shown on the right side of print state management tag 111
Reference numeral 3 denotes a storage location of the pre-developed band image.

The arrows in the figure show the schematic flow of data. First, the print command received from the host computer is stored in the reception buffer 5. Next, the processor 1 reads the print commands from the reception buffer 5 in the order of reception, interprets the print commands, generates intermediate codes for each band, and stores the intermediate codes in the print position management table 7.
Register and go. Note that for the null band, only an intermediate code indicating that the band is a null band is registered.

When the intermediate code for one page is completed in the print position management table 7, the processor 1 activates the print engine 13 and synchronizes with each band in the print position management table 7 in synchronization with the print engine 13. Is rendered into an image and written to the band buffer 9. Each band image in the band buffer 9 is transferred to the print engine 13 by the DMA. still,
For the null band, the processor 1 does not perform rendering to the band buffer 9, but instead generates null data (for example, data of a value “0”) by the size of the null band and sends the null data to the print engine 13.

In the process of generating the intermediate code of each band, the processor 1 monitors whether the amount of the intermediate code of the band exceeds a threshold value. If the threshold is exceeded, it means a situation in which an overrun is likely to occur, or a situation in which the amount of intermediate code is greater than the image. In that case, the processor 1 secures the external band buffer 11 for the band, pre-develops the image of the band in the external band buffer 11, and further includes one indicating that the band is a pre-development band. (In which the pointer of the external band buffer 11 is registered) is generated and registered in the intermediate code buffer of the band in the print position management table 7. For example, in the example shown in FIG. 2, the band in the fifth printing order is the pre-expanded band.

The image of the pre-development band in the external band buffer 11 is not copied to the band buffer 9 at the time of printing the band, and is not copied to the external band buffer 11.
3 is transferred to the print engine 13 by DMA.

The band image in the band buffer 9 is
When the transfer to the print engine 13 is completed, the page is cleared by the processor 1. However, the pre-developed band image in the external band buffer 11 is not cleared even after the transfer to the print engine 13 is completed, and the page (for double-sided printing) is not cleared. In this case, the data is stored until the required number of pages (the page on the opposite side of the page) have been printed and the printed sheet is discharged.

A particularly important function in the present embodiment shown in FIG. 2 is that the pre-development image in the external buffer 11 is directly transferred to the print engine 13 without passing through the band buffer 9. The configuration and processing operation adopted by the present embodiment to realize this function will be described in detail below.

FIGS. 3 and 4 show the print position management table 7.
Shows the configuration of the intermediate code registered in.

FIG. 3 shows the structure of an intermediate code of a normal band that is neither a pre-development band nor a null band. The intermediate code amount of a normal band varies depending on the band. The amount of intermediate code increases during the process of creation, and the amount of intermediate code cannot be determined from the beginning.
Therefore, as shown in FIG. 3, a plurality of intermediate code buffers 731 of a fixed size are connected and used. At the end of each intermediate code buffer 731, the next intermediate code buffer 7
A code called a “link code” which is a pointer to 31 is entered (the last intermediate code buffer 73 of each band).
The link code of 1 is a pointer to the first intermediate code buffer 731 of the next band).

FIG. 4 shows the structure of the intermediate code of the pre-expanded band. The intermediate code of the pre-expanded band includes one predetermined intermediate code 733 indicating that the band is a pre-expanded band and a link code 735 which is a pointer to the next band, and is stored in one intermediate code buffer 731. You. In the intermediate code 733 indicating that the band is a pre-developed band, a pointer to the external band buffer 11 storing the pre-developed image is registered. Therefore,
The external band buffer 11 can be referred to from the intermediate code 733.

As understood from the intermediate code structure shown in FIGS. 3 and 4, the intermediate code of one page is registered in the print position management table 7 in the form of a large number of serially linked intermediate code buffers 731. Therefore, all the intermediate codes from the top to the end of the page can be sequentially followed according to the link.

FIG. 4 further shows the configuration of the external band buffer 11 storing the image of the pre-development band.

The external band buffer 11 includes the print state management tag 111 and the storage location 113 of the pre-developed band image as described above. The print state management tag 111 includes an identification number 115 of the band buffer 11, a print state code 117, and a pointer 119 to a storage location 113 of the band image.

FIG. 5 shows the structure of a normal band buffer 9.

Each band buffer 9 also has a print state management tag 91 and a band image storage location 9 as described above.
And 3. The print state management tag 91 includes an identification number 95 of each band buffer 9 and a print state code 97.
And a pointer 99 to the storage location 93 of the band image.

As can be seen from a comparison between the external band buffer 11 of FIG. 4 and the band buffer 9 of FIG. 5, both have substantially the same configuration. Therefore, the external band buffer 1
1 can be handled in the same manner as a normal band buffer 9. The print status codes 117 and 97 in these buffers 11 and 9 indicate “rendering” indicating that the image is being rendered, “rendered” indicating that rendering has been completed and can be transferred to the engine, and Of the image is being transferred, and “empty” indicating that the image transfer to the engine has been completed.

FIG. 6 shows the overall flow of processing performed by the processor 1 for printing each page.

When receiving the print command from the host computer (S1), the processor 1 temporarily stores the print command in the receive buffer 5, reads the print commands from the receive buffer 5 in the order of reception, and interprets the print commands (S2). By interpreting the print command, the processor 1 generates an intermediate code (S4).

The details of the intermediate code generation processing in step S4 are as shown in FIG. First, one page is divided into a plurality of bands, and the printing position of the band currently being processed on the paper is determined (S11). Subsequently, an intermediate code is generated for the band currently being processed and registered in the print position management table 7 (S12), and the amount of the intermediate code generated so far for the band is calculated (S13). This intermediate code amount is used to determine whether or not it is necessary to pre-deploy.

Referring again to FIG. 6, after step S4,
The intermediate code amount of the band currently being processed is compared with a predetermined threshold value (S5). If the intermediate code amount does not exceed the threshold value, the above-described intermediate code generation process is continued. If the intermediate code amount of the band currently being processed exceeds the threshold, the band is pre-developed (S6).
The details of this pre-expansion processing will be described later.

As described above, each band is sequentially converted into an intermediate code. When all the intermediate codes of one page are registered in the print position management table 7 (Yes in S3), the processor 1 then proceeds to steps S7 and S8. Enter rendering processing. The processor 1 sequentially traces the intermediate codes registered in the print position management table 7, and first checks whether or not the band to be printed is a pre-developed band (S7). If the band is not a pre-development band, the processor 1 renders an image of the band in the image buffer 9 based on the intermediate code of the band (S8).

The details of the rendering processing in step 8 are as follows.
This is as shown in FIG. First, the print position management table 7
(S15), and if the state of the band buffer 9 allocated to the band to be printed becomes "empty" (S16, S17), the band image is rendered from the read intermediate code to render the band. Writing to the buffer 9 (S18). During rendering, the print status code 97 of the band buffer 9 is set to “rendering”, and when rendering is completed, the print status code 97 is changed to “rendered” (S19).

Referring to FIG. 6 again, when the rendering of the band to be printed is completed, the printing process of the band is performed (S9). The print processing is performed by sending the image in the band buffer 9 to the print engine 13 by DM.
The transfer is performed by A. If the band to be printed is a pre-developed band (Yes in S7), the printing process for that band can be started immediately. The printing process of this pre-developed band
As described above, this is performed by transferring the image in the external band buffer 11 to the print engine 13 by DMA. Details of this printing process will be described later.

The processing of rendering and printing for each band is repeated until the last band of one page (S10).

FIG. 9 shows the flow of the pre-expansion processing in step S6 in FIG.

The processor 1 first secures the external band buffer 11 in the memory 3 (S 21), and then renders an image of the band from the intermediate code of the band currently being processed and writes it in the external band buffer 11. (S2
2). Next, the processor 1 creates an intermediate code for the pre-development band as shown in FIG. 4, that is, a predetermined intermediate code in which the pointer of the external band buffer 11 is registered as an image, and creates the intermediate code. (S23).

FIG. 10 shows the flow of the printing process in step S9 of FIG. In the description of this processing, the “band buffer” means the external band buffer 11 for the pre-expanded band, and the band buffer 9 for the normal band that is neither the pre-expanded band nor the null band.

As shown in FIG. 10, first, the print status code 97 or 117 of the band buffer assigned to the band to be printed is checked (S31). The image in the buffer is transferred as video data to the print engine 13 by DMA (S32). During the transfer, the print status code 97 or 117 of the band buffer is set to “transferring”, and when the transfer is completed, the print status code is changed to “empty” (S33). Thereafter, if the band for which the image transfer has just been completed is not the pre-development band (No in S34), the band buffer 9 is cleared in preparation for rendering of the subsequent band (S35), but if it is the pre-development band (S34). Yes), and save the image without clearing it in case error recovery becomes necessary later. The determination in step S34 can be made, for example, from the identification numbers 95 and 115 in the print state management tags 91 and 11 of the band buffer.

If the band buffer of the band to be printed is not "rendered" in step S31, a predetermined process is performed as an overrun error (S36).

According to the above-described embodiment, since the pre-developed band image is directly transferred from the storage location to the print engine at the time of printing, there is no need to copy the pre-developed image to the band buffer. ,
Therefore, the memory use efficiency is improved, and the processing of rendering and transferring the image is made more efficient. For the null band, by sending null data from the processor to the engine, rendering to the band buffer is omitted, so that the memory use efficiency is also improved.

The above embodiment is for the purpose of describing the present invention, and is not intended to limit the scope of the present invention. The present invention can be implemented in various modes other than the specific configurations, functions, processes, and operations illustrated and described above. For example, in the above embodiment, the number of ordinary band buffers is fixedly determined, but this may be variable.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a conventional process.

FIG. 2 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of an intermediate code of a normal band.

FIG. 4 is a block diagram showing a configuration of an intermediate code of a pre-expanded band and a pre-expanded image.

FIG. 5 is a block diagram showing a configuration of a band buffer 9;

FIG. 6 is a flowchart showing an overall flow of processing of a processor 1;

FIG. 7 is a flowchart showing the flow of an intermediate code generation process.

FIG. 8 is a flowchart illustrating a flow of a rendering process.

FIG. 9 is a flowchart showing the flow of a pre-deployment process.

FIG. 10 is a flowchart illustrating the flow of a printing process.

[Explanation of symbols]

 1 Processor 3 Memory 5 Receive Buffer 7 Print Position Management Table 9 Band Buffer 11 External Band Buffer 13 Print Engine 73 Intermediate Code 91, 111 Print Status Management Tag 93, 113 Band Image

Claims (6)

[Claims] 1. A memory, a print engine, means for reserving a normal band buffer in the memory for rendering a normal band image at the time of printing, and a pre-development band image in the memory. Means for securing an external band buffer for pre-rendering, transferring the images in the normal band buffer and the external band buffer directly to the print engine at the time of each printing, and after each transfer, A transfer device for clearing only the image in the normal band buffer in preparation for rendering the image of the next band. 2. The page printer according to claim 1, wherein the normal band buffer and the external band buffer have a print state management tag indicating a respective identification number and a print state, and the transfer unit includes: A page printer that distinguishes the normal band buffer from the external band buffer based on a print state management tag of the normal band buffer and the external band buffer, and controls transfer of an image in each buffer. 3. The page printer according to claim 1, further comprising means for generating null data at the time of printing a null band and directly supplying the null data to the print engine. 4. A memory, a print engine, means for securing each band buffer in the memory for rendering an image of each band, and the image in each band buffer is sent to the print engine when the image is printed. Transfer means for directly transferring, the transfer means discriminates whether the image in each band buffer is of a normal band or a pre-development band, and after each transfer, in each of the band buffers A page printer that clears only the normal band's image in preparation for rendering the next band's image. 5. The page printer according to claim 4, wherein each of the band buffers has a print state management tag indicating a respective identification number and a print state, and the transfer unit manages a print state of each of the band buffers. A page printer that discriminates whether an image in each of the band buffers is from the normal band or the pre-deployed band buffer based on a tag, and controls each transfer. 6. The page printer according to claim 4, further comprising means for generating null data at the time of printing a null band and directly supplying the null data to the print engine.