JP3264257B2 - Printing system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a printing system, and more particularly to a printing system capable of generating a raster image at high speed by parallel processing.

[0002]

2. Description of the Related Art In recent years, page printers that obtain a raster image from page description data described in a page description language (PDL) and print the raster image have become widespread.
When such a page printer is used as a server, print requests from many host devices are received and printed, and therefore, it is demanded to reduce a waiting time from a print request to printing.

For this reason, in order to execute image formation at high speed, there has been proposed a method of executing a drawing operation as a plurality of processes in parallel. An example of a conventional parallel print data processing system is described in Japanese Patent Application Laid-Open No. H10-58770. As shown in FIG. 9, this conventional printing system includes a program dividing unit 42, a divided PDL program 40a,
40b, 40c and band dividing units 20a, 20b, 20
c, PDL interpreters 34a, 34b, 34c,
Linearization processing units 30a, 30b, and 30c;
It is composed of

A conventional printing system having such a configuration operates as follows. That is, the PDL program 2 sent from the host device is divided into the program division unit 4
Sent to 2. The program dividing unit 42 divides the received PDL program 2 and generates a plurality of independently drawable divided PDL programs 40a to 40c. The PDL programs 40a to 40c divided into three are divided into band dividing units 20a to 2 of the respective processing devices (CPUs).
0c, where the image of one page is divided into a plurality of band regions (bands) by a boundary line perpendicular to the moving direction of the sheet, and stored in each band memory as a plurality of divided PDL data 32a to 32i. You.

The divided PDL data 32a to 32c correspond to the band at the upper part of the page, the divided PDL data 32d to 32f correspond to the band at the center of the page, and the divided PDL data 32g to 32i.
Represents the band at the bottom of the page. Divided PDL data 32a
To 32c are PDL interpreters 34a, divided PDL data 32d to 32f are PDL interpreters 34b, and divided PDL data 32g to 32i are PDL interpreters 3
4c, the interpreted intermediate code 28a is interpreted and executed.
~ 28c are generated.

[0006] The divided intermediate codes 28a to 28c are converted into vector data 22a to 22c by linearization processing units 30a to 30c, and thereafter, are painted and overlapped by processing units 4a to 24c.
After being stored in the block memories 26a to 26c as bitmap data through the processing in step c, the data is sequentially taken out, output to the printing device 14, and printed.

[0007]

However, the prior art printing system described in Japanese Patent Application Laid-Open No. H10-58770 has the following problems.

[0010] That is, the first problem is that the drawing process is assigned to each band, so that the speed cannot be increased depending on the contents of the page description. The reason is that the drawing object may be biased to a specific band.

A second problem is that the start of printing cannot always be started quickly because drawing processing is assigned to the processor in band units. The reason is that even if many processors (central processing units) are implemented, in the conventional system, drawing of the first band at the head in the printing direction ends first, that is, the block memory 26a in FIG.
Since there is no guarantee that the completion of the printing will be performed first, the printing system that performs the drawing and the operation of the printing device 14 in parallel to end printing at a high speed requires a longer drawing processing time than a single processor. This is because it is difficult to increase the speed.

The present invention has been made in view of the above circumstances, and has as its object to provide a printing system capable of drawing a raster image at high speed.

[0011]

According to a first aspect of the present invention, there is provided a printing system for printing a raster image obtained from page description data described in a page description language. a page description interpretation unit for creating an independent drawing objects by interpreting the description data, the drawing object, the drawing object editing unit that creates a drawing object list order to create a link overlap the bounding rectangle, the Multiple drawing options that can be drawn from the drawing object list
Select each object independently and create a raster image
And an object drawing unit for drawing in parallel .

According to the invention having such a configuration, drawing objects are linked by dependency, and a drawing object that can be drawn by the object drawing section is selected from the linked drawing object list and drawn.
By using a plurality of object drawing units and processing them independently, parallel drawing can be performed without causing bias and drawing of a print image can be speeded up.

[0013]

[0014]

3. The printing system according to claim 2, wherein the object drawing section is an independent drawing object having no overlap or an undrawn child drawing object having an overlap, and a parent drawing object on the front side in the overlapping order. Are configured to select a child drawing object that has already been drawn.

According to the invention having such a configuration, the processing speed can be increased as a whole without causing a bias in the processing amount with respect to the object drawing processes which are independently processed in parallel.

According to a third aspect of the present invention , in the printing system, the page description interpretation unit and the drawing object editing unit include:
A band dividing unit is provided for dividing the drawing object into a plurality of bands, and the drawing object editing unit creates a drawing object list from the drawing objects divided into the bands.

According to the invention having such a configuration, it is possible to increase the speed of a printing apparatus that simultaneously performs drawing and printing.

In a fourth aspect of the present invention, the printing system includes a host device and a printing device, and the page description interpretation section in the printing device interprets the page description data obtained from the host device.

According to the invention having such a configuration, since the above-described printing system is provided in the printing apparatus, it is effective as a print server.

A printing system according to claim 5, comprising a host device and a printing device, wherein the host device is a page description interpreting unit, the drawing object editing unit, and a drawing object created by the drawing object. An object list conversion unit that converts a list into a drawing object description language, wherein the printing apparatus includes an object list restoration unit that restores an original drawing object list from the drawing object description language, and the object drawing unit There is.

According to the invention having such a configuration, since the printing system is divided into the host device and the printing device, the burden on the printing device is reduced, and the speed of the printing device can be further increased.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the printing system according to the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram showing a first embodiment of the printing system of the present invention. The printing system 100 includes a host device 101 such as a client and a printing device 102 such as a print server, and these are connected via a communication line or the like.

The host device 101 has a page description generator 1011 such as a word processor or a printer driver.
In accordance with the format and grammar of the page description language 121 that can be interpreted by the printing apparatus 102, single or plural page description data is generated and sent to the printing apparatus 102.

The printing device 102 has a drawing object 1
A drawing description interpreting unit 1021 for generating a drawing object 22, a drawing object editing unit 1022 for generating a drawing object list 123, and an object drawing unit 102 for drawing a drawing object 122 on a raster image buffer 124.
3 and a print engine 1024 are included.

The page description interpreter 1021 is configured to construct one or a plurality of page images using the page description language 121, and sends the page description language 121 sent from the higher-level device 101. Is interpreted, and from the description for each page, a set of drawing objects, which is an internal representation form of the object to be actually drawn, is created. One drawing figure and one character are developed as one drawing object, and each page is represented as a group of one or more drawing objects 122.

The drawing object editing unit 1022 determines the overlap between the drawing objects 122 based on the boundary rectangle of the objects, and if it is determined that there is an overlap, determines that there is a drawing dependency between the drawing objects. At this time, the drawing object editing unit 1022 expresses the dependency depending on the order of occurrence as a link structure. That is, the drawing description interpreting unit 1021 determines the overlapping of the individual drawing objects 122 generated, and draws the overlapping drawing objects in a list structure having a directionality capable of determining which drawing object should be drawn first. Convert to an object list 123.

For example, as shown in FIG. 2, using the page description language shown in FIG. 2A, a rectangle is drawn as shown in an actual image image shown in FIG. If you draw a character on top, the character will have a dependency on a rectangle. As shown in FIG. 2C, the drawing object list 123 is represented by a link relationship indicating that the drawing object 2 representing a character depends on the drawing object 1 representing a rectangle.

Dependency means that a character cannot be drawn until a rectangle is drawn. When there is such a dependency, in the present specification, the rectangle on the dependent side is referred to as a parent drawing object, and the character on the dependent side is referred to as a child drawing object. If the page description is such that the rectangle and the character are drawn at a completely separated place, there is no dependency between the two drawing objects and the drawing object list is 2.
Each drawing object is generated as a separate list, and indicates that each drawing object can be drawn independently.

In the object drawing unit 1023, from the drawing object list 123, a drawable drawing object, that is, an independent object having no overlap, or a parent drawing which must be drawn before drawing a child drawing object The raster image buffer 12 selects one of the two types of drawing objects, that is, the drawing object in which the object is already drawn and the drawing object that has been drawn or is not being drawn.
4 to a raster image.

The object drawing unit 1023 functions as a program process corresponding to the number of processors that can be allocated for drawing on the printing apparatus 102, and obtains drawing objects 122 that can be drawn independently from the drawing object list 123. And draw.

The print engine 1024 generates a hard copy from the raster image data stored in the raster image buffer 124.

Next, the process of the printing system will be described in detail. First, the page description generation unit 1011 in the higher-level device 101 generates single or multiple page description data according to the format and grammar of the page description language 121 that can be interpreted by the printing apparatus 101. Generate and send to the printing device 102.

The page description interpretation unit 10 in the printing apparatus 102
Reference numeral 21 denotes a drawing object 122 which interprets the page description language 121 received from the higher-level device 101 in 1-page units, and is an internal representation of figures and character information to be actually drawn.
Perform the page interpretation process to convert to.

Next, the drawing object editing process performed by the drawing object editing unit 1022 will be described with reference to FIG. First, in step 201, the drawing object list 123 is initialized, and the drawing object list
In the state 3, no drawing object 122 is registered.

Next, at step 202, it is determined whether or not there is an unprocessed drawing object 122. If there is, at step 203, the drawing objects 122 to be processed are registered in the order registered by the page description interpretation unit 1021. Take out. If there is no unprocessed drawing object 122, the process ends.

In step 204, the extracted drawing object obtains, based on the position and size of the drawing object, the coordinate information of a rectangle (referred to as a bounding rectangle) circumscribing a figure or a character to be drawn by the drawing object. It is calculated and stored in the drawing object 122. At this time, in step 205, the drawing object list 12
It is determined whether or not the drawing object 122 is registered in No.3. If nothing is registered, step 20
In step 6, the extracted drawing object is registered in the drawing object list 123 as a root drawing object that is the first object. The root drawing object is the first drawing object in which there is no drawing object that must be drawn before the drawing object.

On the other hand, if the drawing object 122 is already registered in the drawing object list 123, at step 207, the drawing object currently being processed overlaps the boundary rectangle among the registered drawing objects. Sort drawing objects.

Next, at step 208, it is determined whether or not there are any drawing objects having overlapping border rectangles.
At 06, it is registered in the drawing object list 123 as a root drawing object.

On the other hand, if there is an overlapping drawing object, the number of overlapping drawing objects is determined again in step 209. If there is only one, in step 211,
The link information is mutually saved as the drawing object under processing as a child drawing object depending on the registered overlapping parent drawing object, and registered in the drawing object list 123. If there are a plurality of overlapping drawing objects, at step 210, a multiple drawing object overlapping process described below is called.

As shown in FIG. 4, in the multiple-drawing-object overlapping process, first, in step 2101, for a plurality of rendering objects on which the rendering object being processed overlaps, the respective link lists are approached to obtain a root rendering object. . Next, in step 2102,
The number of overlapping drawing objects belonging to each root drawing object is determined. If there is one for each root drawing object, in step 2103 the drawing object being processed is registered as a child drawing object of each overlapping drawing object. In this case, this child drawing object has a plurality of parent drawing objects.

On the other hand, if there are a plurality of overlapping drawing objects belonging to each root drawing object, that is, if there is a group having a plurality of overlapping drawing objects in a group for each root drawing object, in step 2104, the most Select the overlapping object at the end and remove the parent candidate in the same link row. In step 2105, the drawing object being processed is linked and registered as a child drawing object of the drawing object left as a selection.

The object drawing unit 1023 is started up as a number of processes usable for drawing, out of the number of processors of the printing apparatus 102. Each object drawing process of the object drawing unit 1023 independently selects a drawable drawing object from the drawing object list, and writes a raster image as a buffered raster image.

The conditions of the drawing object that can be drawn are as follows:
Whether (1) the drawing process is not being performed by another process or (2) the drawing process is not completed, and (3) the drawing object (parent drawing object) having no dependency, that is, the root drawing object, 4) Judgment is made on condition that all parent drawing objects have been drawn.

When all the drawing objects 122 have been drawn and a raster image has been formed in the raster image buffer, the raster image is finally sent to the print engine 1024.
And a print (hard copy) is generated.

If it is necessary to draw in parallel with the operation of the print engine 1024 in order to increase the speed of the specification or the processing of the print engine 1024, as shown in FIG. Before the processing by 1022, a band dividing unit 1025 for dividing the drawing object 122 of one page into a plurality of bands may be provided, and the band dividing unit 1025 may perform a process of determining to which band the drawing object 122 belongs. it can. In this case, the drawing object editing unit 1022 creates drawing object lists 123a and 123b for the drawing objects belonging to each band.

Next, the processing of the printing system will be described using a specific example. Page 3 as shown in FIG.
It is assumed that the page description generation unit 1011 of the higher-level apparatus 101 has generated 00. This page image 300 includes a first rectangle 301, a first character 302, a second rectangle 303,
It is assumed that the page description language 121 is composed of five characters 304 and a circle 305 and is described in this order. At this time, the page description interpretation unit 1021 generates five drawing objects 122 in the order in which they appear. This drawing object corresponds to each of the drawing objects 301 to 305 in FIG.
01, drawing object 302, drawing object 30
3, drawing object 304 and drawing object 3
05.

The drawing object editing unit 1022 sequentially processes the drawing objects 301 to 305 in accordance with the flowcharts of FIGS. As a result, FIG.
The drawing object list as shown in is completed. Here, drawing objects 301 and 303 are root drawing objects, drawing object 301 is a parent drawing object of drawing objects 302 and 305, and drawing object 303 is drawing object 304.
The drawing object 305 has both the drawing object 301 and the drawing object 303 as parent drawing objects.

It is assumed that the printing apparatus 102 has two central processing units that can be used, and therefore the object drawing unit 1023 is being executed as two independent processes. Process A and Process B
Call. When the drawing object list 123 is completed in the state of FIG. 7, the processes A and B independently start searching for a drawable object. If the search condition is the order of appearance in the page description, that is, the descending order from the drawing object, the process A searches for a drawable object, selects the drawing object 301 which is the root drawing object, and starts drawing.

Process B also searches for a drawable object, drawing object 301 is being drawn, and drawing object 302 is the root drawing object because drawing object 301, which is the parent drawing object, has not been drawn yet. And select
Start drawing. Process A is a drawing object 301
Is completed, the next drawable object is searched, and the child drawing object 302 that has become drawable because the parent drawing object 301 has been drawn is selected.
Start drawing.

On the other hand, the process B that has finished drawing the drawing object 303 searches for the next drawable object, and since the drawing object 301 has been drawn and the drawing object 302 is being drawn, the parent drawing object 3
The child drawing object 304 that has become drawable because 03 has been drawn is selected, and drawing is started. When the process A finishes drawing the drawing object 302, the drawing object 305 in which both parent drawing objects 301 and 303 have already been drawn is selected and drawing is started. In this way, all drawing is performed in processes A and B.
Complete by The completed raster image is printed by the print engine 1024.

According to the printing system of the first embodiment, drawing objects are linked by dependency, and a plurality of drawing processes independently select drawing objects from the linked drawing objects. , So parallel drawing is possible,
Drawing of print images can be accelerated.

Further, since the central processing units that perform the object drawing process select and render drawing objects that can be independently drawn, the number of central processing units can be freely increased or decreased. It is possible to construct a printing system according to the number.

Further, when the dependency is concentrated on a specific drawing object, the drawing object is divided into bands to reduce the multiplicity and to increase the parallelism in order to reduce the multiplicity of the dependent link. Can be speeded up.

Next, a printing system according to a second embodiment of the present invention will be described in detail with reference to FIG. The printing system 110 includes a host device 111 and a printing device 112. The host device 111 includes a page description interpretation unit 1111 that generates a drawing object 122, a drawing object editing unit 1112 that generates a drawing object list 123, and an object list conversion unit that converts the drawing object list 123 into a drawing object description language 125. 1113 is included.

The printing apparatus 112 includes an object list restoring unit 1026 for restoring the drawing object list 123 from the drawing object description language 125, an object drawing unit 1023 for drawing a drawing object on the raster image buffer 124, and a print engine 1024. included.

Each of these operates roughly as follows. The page description interpreting unit 1111 generates one or a plurality of page images and a set of drawing objects 122 for each page on an internal storage. The drawing object editing unit 1112 includes the page description interpreting unit 111.
1 determines the overlapping of the individual drawing objects 122 generated, and converts the overlapping drawing objects into a drawing object list 123 having a list structure having a directionality capable of determining which should be drawn first. The object list conversion unit 1113 converts the drawing object list 123 into a form of a drawing object description language 125, which is a byte string that can be restored.
Send to printing device 112.

In the printing apparatus 112, the drawing object description language 125 is restored by the object list restoring unit 1025 into the same drawing object list 123 as the original. The object drawing unit 1023 reads, from the drawing object list 123, a drawing object that can be drawn, that is, an independent object having no overlap or a drawing object that must be drawn before drawing the drawing object. The selected drawing object that is not drawn or is not in the middle of a drawing is selected and converted into a raster image on the raster image buffer 124. The object drawing unit 1023 functions as a program process for the number of processors that can be allocated for drawing on the printing device 112, acquires drawing objects that can be drawn independently from the drawing object list 123, and draws them. . The print engine 1024 is connected to the raster image buffer 1
A hard copy is generated from the raster image in 24.

The printing system 110 of the second embodiment
Is basically the same as the printing system 100 of the first embodiment except that the drawing object editing unit 1112 is simply moved from the printing apparatus 112 to the host apparatus 111.

According to this printing system, the drawing object is generated and its link is performed by the host device 111.
Since the processing gravity of object drawing in the processing of the printing apparatus 112 is increased, in a printing apparatus having a plurality of processors, parallelism can be improved and a printing result can be obtained at high speed.

[0061]

As described above, according to the printing system of the present invention, a print image can be drawn at a high speed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a first embodiment of a printing system according to the present invention.

FIG. 2 is a schematic diagram illustrating an example in which a drawing object list is created.

FIG. 3 is a flowchart illustrating a drawing object process.

FIG. 4 is a flowchart showing a process of overlapping a plurality of drawing objects.

FIG. 5 is a configuration diagram illustrating a printing apparatus when a drawing object is divided into bands.

FIG. 6 is a schematic diagram illustrating an image for explaining processing in the printing system.

FIG. 7 is an explanatory diagram illustrating an example of a created drawing object list.

FIG. 8 is a configuration diagram illustrating a second embodiment of the printing system of the present invention.

FIG. 9 is a configuration diagram illustrating a conventional printing system.

[Explanation of symbols]

 Reference Signs List 101 Upper device 1011 Page description generator 102 Printing device 121 Page description language 122 Drawing object 123 Drawing object list 124 Raster image buffer 1021 Page description interpreter 1022 Drawing object editing unit 1023 Object drawing unit 1024 Print engine

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 1/38-1/393 B41J 5/30 B41J 21/00

Claims (5)

(57) [Claims] 1. A printing system for printing a raster image obtained from page description data described in a page description language, comprising: a page description interpreting unit for interpreting the page description data to create independent drawing objects; wherein the drawing object, the drawing object editing unit that creates a drawing object list to create a link in the order of overlap of the boundary rectangle, rendering more drawable from the drawing object list
Select each object independently and create a raster image
And an object drawing unit for drawing in parallel . 2. The printing system according to claim 1 , wherein the object drawing unit is an independent drawing object having no overlap, or an undrawn child drawing object having an overlap, and a parent parent in the order of the overlap. A printing system, wherein a child drawing object in which all of the drawing objects are already drawn is selected. 3. The printing system according to claim 1 , further comprising: a band division unit that divides the drawing object into a plurality of bands, between the page description interpretation unit and the drawing object editing unit. A printing system, wherein a drawing object editing unit creates a drawing object list from the drawing objects divided into the bands. 4. The printing system according to claim 1, further comprising a host device and a printing device, wherein the page description interpretation unit in the printing device acquires a page description acquired from the host device. A printing system characterized by interpreting data. 5. The printing system according to claim 1, further comprising a higher-level device and a printing device, wherein the higher-level device includes the page description interpretation unit, the drawing object editing unit, An object list conversion unit that converts a drawing object list created by a drawing object into a drawing object description language, wherein the printing apparatus restores an original drawing object list from the drawing object description language; A printing system comprising the object drawing unit.