JPH0935073A - Printing equipment - Google Patents

Abstract

(57) [Abstract] [Problem] It is impossible to output a high quality image when rendering cannot be performed according to the engine speed. A printing apparatus that performs high-quality output with a small capacity by recognizing an object that requires complicated drawing and performing compression and expansion according to an area corresponding to the object instead of a band.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing apparatus, and in particular, data used in multimedia processing such as CAD (Computer Aided Design), CG (Computer Graphics), Design, DTP (Desktop Publishing) field in business. The present invention relates to a printing device that prints and records in high definition.

[0002]

Conventionally, in practically used image printers, the PDL sent from the host computer is analyzed, one page is rendered in the full paint memory, and the sheet is discharged.

However, in order to save memory, in recent years, a rendering method by band control (hereinafter referred to as band processing) is performed in which a small band memory is rendered at a high resolution in accordance with the conveyance of paper. With this method, the sent PDL is divided into types such as characters, lines, polygons, images, etc., and one page of information is accumulated as an intermediate language (object) that has information such as the rendering position and the band to draw. It is conceivable that the sheet is held until the sheet is ejected while performing band control with high resolution.

However, when there is an object that performs complicated drawing, the time for drawing the object for a specific band may not be in time for the sheet discharge speed. At this time, it automatically shifts to full-paint mode, which draws the entire page in memory, and saves the objects held up to that point.
Draw in low resolution in order from the first band. Objects that are no longer needed after being drawn are deleted from the memory, and the memory for one page is secured by allocating the memory for full memory, and when all writing is completed, the paper is ejected. Hereinafter, the process of executing the full paint drawing mode at such a low resolution will be referred to as "degrade".

In the above example, it is impossible to render in synchronization with the engine speed when a complicated object such as a curve that takes time to render, or a very large number of objects are drawn in the same band. For this reason, it is transitioning to full paint mode. However, in the full paint mode, there is a problem that high-definition output cannot be performed by making full use of engine performance.

[0006]

In consideration of the above-mentioned problems, the present invention discriminates the overlapping of the drawing areas of the respective objects on the page, and pre-renders the densely overlapping areas. When this method is used, the processing becomes complicated, but since it is possible to consider the area without depending on the bandwidth, it is possible to perform more adaptive and highly efficient compression / decompression processing and memory management. Becomes

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a block diagram showing the basic construction of the "printing apparatus" of the embodiment. A rough flow of processing is shown using this figure.

[Overall Configuration] Reference numeral 1 in the figure is a WS (computer) that creates print information as an application, converts corresponding print data into a PDL format, and sends the data to the recording device controller 14.

Here, PDL data flows between the computer and the recording device. Here, the communication mode may be serial, network, bus connection, or the like, but in terms of performance, a high-speed communication path is desirable. Sent
PDL data is stored in input buffer 2 and program ROM6
The input data is scanned by the PDL command parser in. Reference numeral 3 is a font ROM that stores character bit patterns or outline information, and character baseline and character metric information, and is used when printing characters. The panel IOP 4 is an I / O processor and firmware that controls switch input on the panel attached to the printer body and displays on the LCD, and a low-cost CPU is used. The expansion I / F 5 is an interface circuit with the expansion module (font ROM, program ROM, RAM, hard disk) of the printer. Reference numeral 6 denotes a ROM that stores the software of the present invention, and the CPU 12 reads this data and executes the processing. Reference numeral 7 is a management area for software, which stores data obtained by analyzing the input PDL and converting it into an intermediate data format (object), global information, and the like.

The hard renderer 8 executes the rendering process
By executing with SIC hardware, rendering processing is performed in real time in synchronization with video transfer of the printer engine 13 (LBP), and band processing with a small memory capacity is realized. This may be a region rather than a band. Hereinafter, the band processing is representatively called.
The page buffer 9 is an area for storing an image developed by the PDL language, and it is necessary to secure a memory of at least two bands (page width 256 or band height of about 512) for performing the above band processing. .

The printer interface 10 and the printer engine 13 transfer the contents of the page buffer 9 as video information in synchronization with the horizontal / vertical synchronizing signals on the printer side.

In this interface, between the printer and
Sends commands to the printer and receives status from the printer.

The compression / expansion hardware 11 compresses the band pre-rendered in the page buffer, and expands the band held in the management RAM in a compressed form at the time of pre-rendering or shipping.

The CPU 12 is an arithmetic unit for controlling the processing inside the printer controller. 13 is a printer engine for printing the video signal sent from the controller, and 14
Is the entire controller that realizes this process.

[Processing Flow] The arrows in FIG. 1 indicate the processing flow relating to various drawing information. Figure 2 shows the flow of this process.
This will be described with reference to the flowchart of.

First, the PDL data is loaded into the input buffer. The PDL data captured in step 101 is analyzed in step 102 according to the language specification to generate an object for drawing. Then, in step 103, it is checked in which band on the page the input PDL data is drawn. The detailed flow of step 104 is shown in FIG.

In step 201, for one or a plurality of bands in which the object is to be drawn (it goes without saying that it may be read as a certain area as described above), it is determined whether or not each band is already pre-rendered. To check. If pre-rendered,
In step 202, the pre-rendered and compression-held band is decompressed by 11 compression / decompression hardware, and an object is rendered to the decompressed band in step 203.

The band for which rendering has been completed is compressed again in step 204 and held in the management memory.

In step 205, it is checked again whether there is another band that has been pre-rendered in the same manner as 201.
If so, repeat from step 202.

In step 105, the time for drawing the object is predicted. The prediction is determined by the complexity of drawing the object using a predetermined formula.
In step 106, the time predicted in step 105 is added to the band drawing predicted time of each band in which the object is drawn.

The detailed flow of the next step 107 is shown in FIG. First, in step 301, for the band to which the prediction time has been added in step 106, it is checked whether the drawing prediction time of the band exceeds the shipping time. If it exceeds, it is impossible to perform banding processing, and therefore the band is rendered in advance before the start of shipping (step 302).

The rendered band is memory intensive because it is raster data for a portion of the page. Therefore, compress this and hold it in the management memory.
(Step 303).

By thus pre-drawing a band having a long drawing time, it is possible to realize the generation of a page in synchronization with the engine speed at the time of shipping and prevent the banding process from becoming impossible.

In step 304, it is checked whether all the objects to be processed have been completely prerendered. An object for which drawing has been completed does not need to be drawn at the time of shipping, and is deleted from the management memory (step 305). The detailed flow of step 108 is shown in FIG.

In step 401, it is checked whether the object has filled the management memory. In the past, when the management memory became full, a degradation occurred, and low resolution full page drawing was performed.

In this method, first, in step 402, the data currently being stored in the management memory is searched for data that greatly presses the memory. Next step
At 403, pre-render the retrieved objects into bands. The pre-rendered band is compressed and stored in the management memory (step 404). The size of the band after this compression is smaller than the size of the original object or objects.

When the drawing is completed, the object is deleted from the management memory (step 405). By deleting a large object from the memory, the management memory can be reused.

After performing these processes for all the input PDL data, the printing process by the banding process is started. If the band to be drawn here is a band that has already been pre-rendered, the band is decompressed using decompression hardware and written to the page buffer. In the case of a band that has not been pre-rendered, the object is rendered in real time by the hard renderer as in the case of normal banding processing.

In the above-described embodiment, the band unit is used, but the regions may be replaced as described above. The region in which each object is drawn on the page is examined, and the region where the drawing time is long is determined by the degree of overlap. Then, it is also possible to pre-render that part. In this case, as described above, the band in each flowchart should be read as a certain area.

A detailed description will be given with reference to FIG.

Here, the objects A, B, C are added to the page.
Consider the case of drawing as shown in Figure 6-a.

The upper and lower limits of the vertical drawing area of each object are examined, and the drawing predicted time is accumulated in the overlapping unit of the area of each object.

As a result, the drawing area of the page is divided into five as shown in FIG. 6-b. A value, which is distributed in proportion to the area height, is assigned to each drawing area.

When the predicted drawing time for each area exceeds the drawing time of the engine with respect to the area height, it is determined that the area cannot be drawn in real time at the time of shipping, and pre-rendering is performed.

The pre-rendered area is compressed and held in the management memory.

At the time of banding processing, the pre-rendered area is expanded and expanded in the page buffer to proceed with the processing.

By thus determining the band-independent area, a complicated drawing area can be accurately obtained without depending on the band, so that the overhead due to compression / expansion can be reduced and wasteful pre-rendering can be performed. Instead, it becomes possible to effectively use the management memory.

For the compression / decompression processing, the compression / decompression at 11 in FIG.
I used decompression hardware, but if 12 CPUs are fast enough, I'll use R for 6 programs instead of dedicated hardware
It is also possible to use compression / decompression processing software installed in OM. This makes it possible to prevent an increase in cost due to the use of dedicated hardware.

As described above, according to the present embodiment, the page description language (PDL) sent from the host computer is input and analyzed, an intermediate language for recording is created, stored in the memory, and stored in the intermediate language. On the other hand, the rendering means that enables the rendering by the high resolution band unit at the same time as the page output by the printer engine, the means for switching to the low resolution rendering by software when the rendering process cannot be executed in time, and each drawing object. A method of calculating the predicted drawing time for each and calculating which partial area in the page area consumes the most drawing time, and shipping starts for the part that consumes the calculated drawing time. Pre-render before being done,
(EN) A printing apparatus provided with means for compressing a rendered part and storing it in a memory, and for a region compressed during shipping, means for outputting a page each time the precompressed data is expanded. It has become possible.

[0041]

According to the present invention, it is possible to perform high resolution output with a small installed memory capacity without degrading an object that requires complicated drawing.

[Brief description of drawings]

FIG. 1 is a block diagram showing the basic configuration of a data printing / recording apparatus according to the present embodiment,

FIG. 2 is a diagram showing an outline of an overall algorithm of the present invention,

FIG. 3 shows drawing of an object on a band that has already been pre-rendered,

FIG. 4 is a diagram showing pre-rendering when the predicted drawing time exceeds the shipping time;

FIG. 5 is a diagram showing pre-rendering of an object that occupies a large amount of memory when the management memory is filled with the object;

[FIG. 6] By overlapping of drawing areas for each object,
FIG. 6 is a diagram showing how to determine a region for pre-rendering.

[Explanation of symbols]

 9 page (band) buffer 10 printer interface 11 compression / expansion hardware 12 CPU 14 controller

Claims (2)

[Claims] 1. A page description language (PDL) sent from a host computer is input and analyzed, an intermediate language for recording is created and held in a memory, and a page by a printer engine is stored for the intermediate language. A rendering method that enables rendering in units of high resolution bands at the same time as output, a method that switches to low resolution rendering by software when execution of the rendering process is not in time, and a predicted rendering time for each rendering object A method for calculating and calculating which sub-region of the page area is the one that spends a lot of drawing time, and rendering the calculated drawing-time consuming portion before starting shipping, For the means to compress the rendered part and store it in memory, and for the area compressed during shipping. Pre-rendered means for page output each time extending the compressed data, the printing apparatus comprising: a metropolitan. 2. The printing apparatus according to claim 1, wherein the partial area is an area including a complicated drawing object.