JPH07137353A - Color printer - Google Patents

Abstract

PURPOSE:To realize a color logic drawing at a low cost while keeping an accu racy to some degree by a method wherein When an advanced color logic draw ing is assigned to intermediate information formed by analyzing color page description information, a high-speed hardware rendering is changed over to a software rendering. CONSTITUTION:An object converted by an interpreter is inputted. If the inputted object is a drawing command and the drawing command assigns a processing, such as an overlap drawing or a transmission, that can be performed by a high-speed rendering, a hardware rendering is started. On the other hand, an advanced logic drawing is assigned, a software rendering is executed. Namely, color information in a full-page buffer 407 and a present background object 405 are received and subjected to a logic operation. Thereafter, the result is stored in the full-page buffer 407. In this manner, rendering can be performed at a low cost at a high speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color printing apparatus,
CAD (Computer Aided Design), CG (Computer Graphics), Design, Color D in Business
The present invention relates to a color printing apparatus that prints / records color data used in multimedia processing such as TP (Desktop Publishing) field with high definition.

[0002]

2. Description of the Related Art With the recent advent of high-performance workstations and personal computers, an environment has been established in which full-color characters, figures, and image data can be easily handled. As a result, documents using color,
Color information is used in a wide range of fields such as OHP (overhead projector), slide, art, and design.

[0003]

As described above, the application using the color information on the host computer side is used in a wide range of fields. However, when the color information created on the host side is recorded on the printing device, conventionally, the CPU power (processing function) on the host side is used to match the characters, images, and graphics on the host side with the resolution of the recording device. In general, a so-called dumb printer or video printer is used, which is to develop an image and send it to a color printer. This processing method is characterized by simplifying the mechanism on the printer side and executing a lot of processing on the host side, but when handling color information, it takes a lot of time for communication because of the large amount of data. However, there is a problem that throughput may drop significantly.

On the other hand, in a monochrome printer, a page description language (Page Description Language) is used.
This is an abbreviation for "age" and hereinafter abbreviated as PDL. ) Method, characters, figures, and images are sent as a language from the host side, the printer interprets the PDL language, and various types of information are scan-converted (scan-converted) into a raster memory.
A method of generating a page image is general. Recently, color PDL printers in which the main scanning method is applied to color printers have begun to spread.

However, the color PDL printer follows the language architecture (structure) of the conventional black and white PDL printer, and already renders the black and white, that is, 1-bit information.
The architecture was such that operations such as SET, OR, XOR, etc. are performed for each bit between the information (destination) g) and the figure, image, and character information (source) to be rendered. However, a color printer has a depth for each color plane, for example, RGB (red, green, blue) (for example, 1, 2, 4, 8 bits), and the conventional SET, OR, XOR.
There is a problem that the desired color cannot be obtained if the operation of is performed bit by bit, and therefore, it is called color logical drawing (A
A logical operation function such as dd, Sub, Max, Min, Blend) in consideration of the bit depth is introduced.

However, the above-described color logical drawing has a problem to be solved that it is a very expensive process because it needs to calculate information having color depth for three or four planes. It was

Therefore, in view of the above points, an object of the present invention is to provide a color printing apparatus which can realize color logical drawing at a low cost while maintaining a certain degree of accuracy.

[0008]

In order to achieve the above object, the present invention provides a means for inputting color page description information, and analyzes the input color page description information to create intermediate information for recording. Means, means for performing high-speed hardware rendering on the intermediate information by hardware, and in the case of advanced color logical drawing that cannot be supported by the hardware, the high-speed hardware rendering is switched to software rendering. And means.

In one aspect of the present invention, the high-speed hardware rendering is realized by rendering a YMCK color object on a YMCK page buffer, and the high-level logical rendering is performed on an RGB color page buffer of an RGB color object. It is possible to realize by the rendering of and to automatically switch between both modes according to the data.

As another aspect of the present invention, the high-speed hardware rendering is realized by rendering a YMCK color object on a YMCK page buffer, and in the advanced logical drawing, a YMCK color object and a YMCK color page buffer are used. This is realized by converting each data from YMCK color to RGB color, executing a logical operation in the RGB color space, and then converting the operation result to YMCK color and storing it in the YMCK color page buffer. Can be automatically switched according to the data.

[0011]

According to the present invention, the color logical drawing function is realized at a high cost without sacrificing the color reproducibility to some extent, that is, by lowering the resolution and gradation. That is,
High-speed rendering with hardware enables logical rendering with high-speed rendering in hardware (here, high resolution,
High gradation), logical drawing that cannot be supported by hardware is realized by software. As a result, it is possible to support a wide range of logical drawing functions at a certain printing speed, and it becomes possible for the printing apparatus to execute the rendering processing that was conventionally performed only on the host side as an image printer. As a result, the load on the CPU of the host is reduced, and it is easy to expand to CPU-intensive (intensive) multimedia processing, which is expected to spread in the future.

[0012]

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

FIG. 1 shows the basic arrangement of an image processing system of a color printing apparatus according to an embodiment of the present invention. A rough flow of processing in the embodiment of the present invention will be described with reference to this figure.

(Overall Structure) In FIG. 1, reference numeral 1 denotes color information as a color application, color and data corresponding to this color information are converted into a PDL format, and the converted PDL data is recorded in a color printing apparatus. It is a host computer (workstation) for sending to the device controller 14. Here, PDL data flows between the host computer 1 and the recording device 14. There is no problem in the communication form of the PDL data, such as serial, network, bus connection, etc., but it is desirable to use a high-speed communication path in terms of performance. The color PDL data sent to the recording device controller 14 is temporarily stored in the input buffer (data input buffer) 2, and the input data is scanned by the PDL command analysis program in the program ROM 6. A font ROM 3 stores a bit pattern or outline information of a character, and a character baseline or character metric information, which is used when printing a character. A panel IOP (input / output processor) 4 is an I / O processor and firmware (panel I / O processor) that controls switch input in a panel mounted on the printer body and displays on an LCD (liquid crystal display). A low-cost CPU is used. The expansion I / F (interface) 5 is a printer expansion module (font ROM, program ROM,
It is an interface circuit with RAM, hard disk).

The program ROM 6 is a memory for storing the processing procedure (software) as shown in FIG. 2 according to the present invention, and the CPU 12 reads the main color PDL data according to the software and executes the processing. Reference numeral 7 denotes a RAM in a management area for software, in which data obtained by analyzing input color PDL data and converted into an intermediate data format (page object), global information, and the like are stored in the main management RAM 7.

The color conversion hardware 8 is used in the ink processing of the printer from RGB (additive color mixture) of red, green, and blue of the color system of the monitor normally used in the workstation (WS) to yellow, magenta, and cyan. , Hardware for converting black to YMCK (subtractive color mixture). This color conversion process requires a great deal of calculation power for non-linear log conversion, 3 × 3 matrix calculation, etc. in pursuit of color accuracy. Therefore, in terms of hardware, the table lookup process is used to increase the speed. . This color conversion parameter is initially adjusted to the optimum value for the printer engine. However, if the host requests the color conversion method to be changed, the color conversion algorithm can be changed to that defined by the user by changing the value in the table. It is possible to change.

The hard renderer (hardware rendering circuit) 9 executes color rendering processing by ASIC (application specific IC) hardware,
Color printer (for example, laser beam printer) 13
The rendering process is performed in real time in synchronism with the video transfer, and the banding process is realized with a small memory capacity. The page (band) buffer 10 is PDL
This is an area for storing images developed by the language, and is a memory of at least two bands for performing the above-mentioned banding processing (page width * 256 or band height at the 512th place * 3 (RGB) or 4 (YMC) as the number of planes.
K) * bit depth), or resolution and / or color gradation in devices that need to transfer images in synchronism with the printer engine, such as LBP (laser beam printer) when banding processing cannot be performed. It is necessary to secure full-color bitmap memory that has dropped. However, in the case of a mechanism in which the controller side can control the movement of the recording head, such as an inkjet printer, the above 2
The memory of the band is the minimum.

A printer interface (I / F) 11 synchronizes the contents of the page buffer 10 with a color printer (color recording device) 13, for example, a color LBP, in synchronization with horizontal / vertical synchronizing signals on the printer side, and outputs video information. To transfer. Alternatively, head control in the color inkjet printer and transfer of video information according to head sizes of a plurality of lines are performed. Further, the printer interface 11 transmits commands to the color printer 13 and receives statuses from the printer. A CPU (Central Processing Unit) 12 is an arithmetic unit that controls the processing inside the recording device controller 14.
The color printer 13 prints the video signal sent from the controller 14 in color on a recording medium. The color printer 13 may be an electrophotographic color LBP or an inkjet printer.

(Processing Flow) The arrows in FIG. 1 indicate the processing flow from the host computer 1 to the printer 13 regarding various drawing information. The flow of this processing will be described with reference to the flowchart of FIG.

First, in step 101, color PDL data is fetched into the input buffer 2 by interrupt processing or the like, and then in step 102, the input PDL command is interpreted according to the language specification.
As a result of the interpretation, when the input data is a drawing command, for example, a character, a straight line, or an image drawing in step 103, the page object format supported by the hardware (or software) / rendering circuit (software) 9 is displayed in step 104. Convert.

(Rendering Model) To understand the following description, the rendering model in this embodiment will be briefly described with reference to the schematic diagram of FIG. This model includes geometrical information of various drawing data, that is, mask information 151 indicating which part is a drawing target, background information 152 indicating what color the mask should be painted, and logic. Drawing method 153 (SET, O
R, XOR, BLEND, ADD, etc.). When clipping with an arbitrary shape, the shape data is first clipped, and only the area remaining after this clipping is used as a mask. As a result, an example of the rendered image is shown at 154.

(Mask) The mask information supported in this embodiment is assumed to be run length (one scan line in the X direction), a convex polygon with no edges intersecting, a bitmap image, and a bitmap font. As can be seen, the mask information has a structure suitable for high-speed hardware rendering. For example, the pentagon shown in FIG. 4A has the intersection shown in FIG. Do not divide into 5 triangles (In this example, the fill is even-o
dd (odd-even method) rule is applied). Further, in the line connection processing unit shown in FIG. 4C, after applying the DDA algorithm in this module to develop the line connection portion in another area, the final external shape is changed to the Y scan line. Each time minx and maxx are held by the run length method, and thereafter, high-speed rendering (step 11
Prepare for 1).

Since each mask object finally generated is rendered with a memory capacity smaller than the full page memory, that is, banding, the page memory is divided into a plurality of bands (height is preferably a power of 2;
2 dots is optimal. ), Each mask object is sorted into each band, and each mask object is displayed in each band as shown in FIG.
The linked list shown in FIG. At this time, regarding polygons that straddle the bands, polygon information is shared by each band. In step 105, the decoding time and rendering time of the data required at the time of rendering are added to each band for the mask divided into each band. This is retained for each band i, and pre
d-decode (i), pred-render
(I). Here, the decoding time is almost proportional to the data amount of the created object. But band 3
As for the decoding time of the triangles 1 and 4 (see (B) of FIG. 4) in, an extra time is required to obtain the offset of the start point of band 3 from the start point of the previous band 2.

The rendering time is calculated by the following formula: mask area in band × background color depth × number of color planes × calculation factor depending on the type of logical drawing.

Returning to FIG. 2, if the input data is not a drawing command, it is determined in step 106 whether the input data is various attribute (background, logical drawing) setting command. If YES (affirmative determination), the corresponding current state setting processing is executed in step 107, but these attribute setting commands are converted into data formats (page objects) that can be read by the hardware (or software) renderer. It is for. Further, as in the present embodiment, since the color logical drawing function is not supported by hardware, when such attribute setting command information is detected, the full paint flag (full-p-lag) is set in step 107. As a result, in step 102, the resolution and / or gradation of printing is forcibly reduced and rendering in the full paint mode is performed. Similarly, the banding process is also impossible for commands such as Flood Fill (point-designated fill).

(Background) The background information indicates how to add color and shade to the mask. As the type of background information, it is possible to specify a background pattern that is attached to the mask without repeating the image and a tile pattern that is attached to the mask by repeating the pattern in the vertical and horizontal directions.
In this embodiment, since a color printing apparatus is assumed, color information can be designated for images, patterns, and tiles.

In step 108, the current state is dumped for the purpose of debugging, for example. In the next step 109, it is determined whether or not the processing of the interpreter 120 has finished parsing the PDL command for one page, and if it is finished, the processing shifts to the renderer 121 of step 110. If not, the process returns to step 102 and the analysis of the next command is repeated. The processing up to this point is basically the data filtering task from the PDL to the page object, and the subsequent processing is the rendering task for drawing in the page buffer 10. These two tasks are implemented as separate tasks on the real-time OS (operating system) because the rendering task requires real-time processing, and the latter rendering task is more important than the former interpreter task. Operates with a high priority set.

In (band rendering) step 110, it is determined whether or not band rendering (banding) processing is possible as pre-processing for rendering the page object. The cases where this banding process is impossible are listed below.

The above-mentioned Flood Fill instruction or the like exists in the page.

Management RAM by inputting a large amount of images
Information of 7 overflowed.

The color printer 13 is an electrophotographic LB
As with P and LED (light emitting diode) printers, once paper is fed and recording is started, the banding process needs to perform video signal transfer to the printer 13 and rendering to the band in parallel. 105
Rendering time pred-d for each band calculated in
Regarding ecode (i) and pred-render (i), one of the bands exceeds a predetermined threshold.

If the above conditions are met, banding cannot be executed, so the resolution or gradation is reduced and a full paint memory is secured in the memory of the page buffer 10 for rendering. On the other hand, in an apparatus such as an ink jet printer in which the movement of the recording head can be controlled by the controller side, the rendering time (the third condition) is not limited to the above, and the movement of the head is reduced when the rendering speed decreases. By delaying, banding processing is possible.

The banding process will be described below with reference to FIG. In band rendering, the page object information created in the management RAM 7 by the PDL analysis task 201 of the interpreter is read by the hardware or software renderer 9 activated by the rendering task 202, and the scan line information at the Y coordinate is read from the mask information. (X min, x max) is extracted, and the corresponding background information is written in the page buffer (band buffer) 10 with reference to the current background information and the logical drawing mode. Then, the Y information is changed so as to correspond to the Y coordinates of all the masks, and the rendering is executed. Since this system assumes a color printer, the page buffer has four sides, that is, Y.
There is an MCK plane, and each color information is rendered for each plane.

Here, there are the following three types of logical drawing that can be supported by the hard renderer, where the source pattern (S) and the destination pattern (D) are used. These do not support processing that requires computing power, such as inputting both information between patterns S and D, computing between both and setting to pattern D. This is because it is necessary to refer to four color planes, and when each plane has 4 to 8 bits, the amount of data calculation becomes very large.

Overwrite (D = S) -Transparent, do not draw on D (D = D) -White (D = 0) Normally, it is assumed that advanced color logical drawing data is not frequently sent from the host computer. In order to speed up data processing that can be supported by this hardware as much as possible, or because the color model of the printer is YMCK, the color information of the background is YMCK. In step 107, the R sent from the host when the background information is analyzed and the data is stored in the management RAM.
Y for GB data using color conversion hardware 8
It is converted to MCK color and held as background information. Although it is conceivable that the color conversion is realized by software instead of hardware, it is preferable to use hardware for speeding up the processing.

In this way, the hardware renders the page object with the band number i according to the mask information, the background information, and the logical drawing method, and at the same time, the horizontal synchronization signal sent from the printer 13 is converted. At the same time, the band information of the band number i-1 which has already been rendered is sent to the printer 13 through the printer interface 11 as a color video signal (YMCK). In this banding process, the page data consisting of the above-described three color logical drawings can be printed at a sufficiently high speed. Also, the page description languages PostScript, LIPS, etc., which are currently widely used, are
Since it complies with this simple color drawing logic, much data can be rendered at high speed by this banding process.

(Logic drawing) A method for realizing an advanced logic drawing function which is not supported by the hard renderer 9
This will be described with reference to the flowcharts of FIGS. 6 and 7 showing the flow of color information. At the time of this logical drawing, the color background information (RG
(B data) 401 is a page object format (RGB) that rendering hardware or software can handle.
obj) 405.

(Page Object Conversion) First, in order to realize the following high-level logical rendering, in a printing apparatus that requires real-time rendering such as LBP, the resolution and / or gradation are reduced instead of band rendering. Rendering is performed on the full page buffer 10. Further, since the hard renderer 9 is required to simplify and speed up the processing, it is not possible to execute run-time or real-time resolution conversion of convex polygon information at the time of rendering. Therefore, the following processing is necessary, but this is not the case in inkjet printers and the like.

As the preprocessing for rendering, for example, 60
When reducing the resolution from 0 DPI (dots / inch) to 300 DPI, the run length is 1 for 2 lines at a time.
Two run lengths, and convex polygons perform recalculation of vertex information. This is executed by the interpreter task 201 for all mask information in the page buffer. The run length is x _l (i), x _r (i), x _l (i + 1), x at the start and end points of the X coordinates of two lines i and i + 1, for example, at 600 DPI.
Assuming _r (i + 1), one start and end point in the new 300 DPI is as follows.

[0040]

## EQU1 ## new- _xl (i) = min.1 / 2 (x
_l (i), x _l (i + 1)), new−x _r (i) = max · 1/2 (x _r (i), x
With respect to the _r (i + 1)) image, the image information itself of the page object does not change, and the scaling factors in the x and y directions are set to 1/2.

On the other hand, even if the gray level of the page buffer is lowered, the renderer can easily cope with it by using 1, 2, 4,
Since it supports 8-bit rendering, the load of interpreter preprocessing is not heavy.

(Full Paint Rendering) FIG. 7 is a flowchart showing the processing procedure of the portion related to rendering after this processing. The object converted by the interpreter in step 501 is input, and it is determined in step 502 whether the input object is a drawing command. If it is not a drawing command, in step 505 the background information and (logical) drawing mode are substituted into the global variables holding the current information. Next, the process proceeds to step 507 described below.

If the input object is a drawing command, the current logical drawing mode is checked in step 503. If the drawing mode is a process capable of high-speed rendering by hardware such as overwriting and transparency, the hard rendering is activated in step 506. This is the same processing as the high-speed hard renderer by banding, which has already been explained. The only difference is that in the case of high-speed banding processing, rendering is performed in YMCK colors, and in this full page mode rendering is performed in RGB colors, so different dither matrices must be loaded in advance.

On the other hand, when advanced logic drawing is designated, software rendering is executed in step 504. This is a page buffer (D, destination) 40 of a full page as indicated by 406 in FIG.
7 and the current background object (S, source) 405 color information is fetched (acquired),
After performing the logical operation, the result is stored in the full page buffer 407. Here, as a typical logical operation processing, the following operation is performed for each RGB component in consideration of the bit depth. In software rendering, the source image is created by applying the same algorithm as the hard renderer 9 to apply the logical drawing described below. A page buffer access library is created for each logical drawing method. . Since soft rendering and hard rendering are mixed, when hard rendering ends, an interrupt occurs in the CPU 12,
This is a mechanism for the CPU 12 to continuously fetch the next page object.

Addition, D = S + D Subtraction, D = D-S Blend value is specified by user, D = α × S + (1-
α) × D ・ Maximum value, D = Max (S, D) ・ Minimum value, D = Min (S, D) This advanced logic drawing is generally performed by the host computer 1 by C
It is calculated on the RGB data used in the RT (cathode ray tube) display. Therefore, in order to perform the same color reproduction as that of the host computer, it is necessary to realize it on the RGB color model even inside the printer. Therefore, in the logical paint full paint mode, the page buffer 407
Must be an RGB color model. Also, the page object information 405 needs to be an RGB color model.

As described above, in the high-speed banding processing, the background information in the page object information is held by the YMCK color model.
You also need to have a GB color. As a result, step 50
When the rendering process of the data for one page is completed in step 7, after converting all the information in the page buffer 10 from RGB to YMCK in step 508,
The YMCK video data is sent to the printer 13 through the printer interface 11 in step 509.

(Printing example of color logical drawing) Finally, FIG.
Is used to show the result of logical drawing. Although this original drawing is in color, it cannot be attached as a drawing, so the colors are indicated by hatching for convenience. In the figure, R is red (red), G is green (green),
B is blue, Y is yellow.
w) and M are magenta, C is cyan, and W is white. This is an example in which a logical operation is performed in consideration of the bit depth of D = S + D, and shows the principle of additive color mixture of CRT. Cyan = Green + Blue, Yel in the figure
low = Red + Green, Mazenta = Red
+ Blue, White = Red + Green + Blue
It is generated by adding e.

(Color Recording Device 13) FIG. 9 shows the appearance of a color ink jet printer device IJRA as an example of the color recording device 13 to which this embodiment can be applied. still,
Controllers other than the color recording device 13 in FIG. 1 are not shown in FIG. In FIG. 9, a drive motor 5013
Driving force transmission gears 5011, 500
The carriage HC is engaged with the spiral groove 5004 by the lead screw 5005 that rotates via 9. The carriage HC has a pin (not shown) that engages with the spiral groove 5004.
, And thereby reciprocates in the directions of arrows a and b. An inkjet cartridge IJC is mounted on the carriage HC. A paper pressing plate 5002 presses the paper against the platen 5000 along the moving direction of the carriage HC. Reference numerals 5007 and 5008 are photo-couplers, and are home position detecting means for confirming the existence of the lever 5006 of the carriage HC in this area and switching the rotation direction of the motor 5013. 5016 is an inkjet cartridge IJC
Is a cap member for capping (covering) the entire surface of the recording head, and 5015 is a suction means for sucking the inside of the cap member 5016.
The suction recovery of the recording head is performed via 023. 501
Reference numeral 7 denotes a cleaning blade, and reference numeral 5015 denotes a member that allows the cleaning blade to move in the front-rear direction, which are supported by a main body support plate 5018. Needless to say, as the cleaning blade, not only this form but also a known cleaning blade can be applied. Reference numeral 5012 is a lever for starting suction for suction recovery, and the cam 50 with which the carriage HD is engaged.
The movement of the drive motor 5013 is controlled by the known transmission means for switching the clutch. These capping, cleaning, and suction recovery are performed by the action of the lead screw 5005 when the carriage HC comes to the area on the home position side.
Although the desired processing can be performed at the corresponding positions, the operations may be performed at timings other than these.

(Other Embodiments) The structure of another embodiment of the present invention is shown in FIG. In the above-described embodiment shown in FIG. 6, an example in which a YMCK page object and a YMCK page buffer are held during high-speed rendering by banding, and an RGB page buffer and an RGB page object are held during advanced logical drawing is shown. . In this example, it is necessary to have page objects in both RGB and YMCK color modes.
Consumes a large area of the management RAM 7. Therefore, in FIG.
In the present embodiment shown in FIG. 0, an example in which the recording area is reduced by holding the page buffer and the page object in YMCK during both the high speed banding process and the logical drawing is shown.

Since the upper half high speed banding process in FIG. 10 is the same as that shown in FIG. 6, the description thereof will be omitted, and the lower half logical drawing path will be described. When rendering by advanced logical drawing of color, the color conversion unit 605 first sets the background data 603 of the page object corresponding to the source (S) to Y.
Reverse conversion from MCK to RGB. Similarly, the portion of the page buffer (D) 604 that has already been rendered and that is logically drawn with the source is similarly converted into the color conversion unit 60.
Reverse conversion at 8.

The problem here is the color conversion processing 602.
Inverse conversion can be easily calculated by performing a simple log conversion when converting from RGB to YMCK in the color conversion processing of, but when UCR (under color removal processing) and masking processing are performed, RG without losing accuracy from YMCK completely
It is impossible to convert back to B. Moreover, the amount of calculation is too large to perform such conversion in real time.

Therefore, in the processing of this embodiment, an approximate conversion table from YMCK to RGB is previously obtained by simulation for each of the patterns 2, 4 and 8 of each bit depth and is obtained by using this approximate conversion table. RG
The B data is used as the inverse conversion data. When the approximate conversion table has 2 bits, the table has 256 bytes and 4
In bits, the table is 65,536 bytes,
These are achievable memory sizes. However, since the amount of data is too large in the case of 8 bits, whether to sacrifice color accuracy by using a 4 bit table, or whether to calculate by software with the intention of increasing the calculation time,
The user should be able to select.

Then, after performing a logical operation 606 based on the information of S and D in the RGB model obtained as described above, the obtained RGB data is converted into YMCK data using the color conversion hardware 8. Then, it is stored in the page buffer 10. Finally, the stored data is transferred as a video signal to the color recording device 13 through the printer interface 11.

[0054]

As described above, according to the present invention,
About printing color PDL (Page Description Language) information,
Simple logical drawing (SET, OR, transparent) etc. is performed at high speed by using hardware rendering, and the advanced logical operation function reduces the resolution and gradation slightly by separating the functions of hardware rendering and software rendering. Since we aimed to reproduce colors to some extent, the effect of being able to render at low cost and at high speed is obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a basic configuration of a color printing apparatus according to an embodiment of the present invention.

FIG. 2 is a flowchart showing an outline of an entire algorithm according to an embodiment of the present invention.

FIG. 3 is a configuration diagram showing an imaging model according to an embodiment of the present invention.

FIG. 4 is an explanatory diagram related to various mask information according to an embodiment of the present invention.

FIG. 5 is a diagram showing a concept of band rendering according to an embodiment of the present invention.

FIG. 6 is an architecture diagram related to color processing in logical drawing according to an embodiment of the present invention.

FIG. 7 is a flowchart showing a procedure of logical drawing in full paint rendering according to an embodiment of the present invention.

FIG. 8 is a diagram showing a result of color logical drawing according to an embodiment of the present invention.

FIG. 9 is a perspective view showing a mechanism of a color recording apparatus applicable to the present invention.

FIG. 10 is an architecture diagram related to color processing at the time of logical drawing in another embodiment of the present invention.

[Explanation of symbols]

 1 host computer 2 data input buffer (input buffer) 3 font ROM 4 panel I / O processor (panel IOP) 5 extended interface (extended I / F) 6 program ROM 7 management RAM 8 color conversion hardware (color conversion H) / W) 9 hardware rendering circuit (hard renderer) 10 page (band) buffer 11 printer interface (printer I / F) 12 CPU 13 color recording device (printer) 14 controller

Claims (3)

[Claims] 1. A means for inputting color page description information, a means for analyzing the input color page description information to create intermediate information for recording, and a high-speed hardware rendering by hardware for the intermediate information. And a means for switching the high-speed hardware rendering to a software rendering in the case of advanced color logical drawing that cannot be supported by the hardware, the color printing apparatus. 2. The high speed hardware rendering is Y
It is realized by rendering an MCK color object on a YMCK page buffer, and the advanced logical drawing is RG.
The color printing apparatus according to claim 1, wherein the color printing apparatus is realized by rendering a B color object on an RGB color page buffer, and automatically switches between modes of both in accordance with data. 3. The high speed hardware rendering is Y
This is realized by rendering an MCK color object on a YMCK page buffer, and in the advanced logical drawing, the data of the YMCK color object and the data of the YMCK color page buffer are respectively converted from YMCK color to R.
After converting to GB color, logical operation is executed in RGB color space, then the operation result is converted to YMCK color and stored in the YMCK color page buffer, and it is realized automatically between both modes according to the data. The color printing apparatus according to claim 1, wherein the color printing apparatus is changed over.