JPH11188927A - Print processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a print processor in which time lag of starting transfer of toner image is absorbed efficiently at the image forming sections (photoreceptor) for respective colors by a tandem color image output means. SOLUTION: Print data describing writing elements, e.g. characters, figures and images, inputted from a print data input means 1 is converted by an intermediate data generating means 2 into an intermediate data which is stored in an intermediate data storing means 3. The intermediate data is read out sequentially by intermediate data developing means 5a-5n according to a time series corresponding to the distance between the image forming sections while being written in an intermediate data butter means 4. When the final intermediate data developing means 5n finishes reading, a newly developed intermediate data is written in a memory area where the intermediate data of that band had been written. Since a memory for storing an image data from the intermediate data developing means 5a-5n is not required, cost can be reduced.

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 more particularly, to an image forming section (photoreceptor) corresponding to a plurality of printing colors.
And a print processing apparatus for a tandem-type color image output apparatus in which full-color printing is completed in one pass.

[0002]

2. Description of the Related Art Conventionally, when performing color printing, a host computer connected to an image output device transfers generated coded data or video data which can be transferred at high speed to a desired image output device and performs coding. In the case of the converted data, the processing unit in the output device converts the desired coded data into a raster image, that is, video data corresponding to YMCK (yellow, magenta, cyan, black) which is a printing color, It is supplied to the image output device and printed.

FIG. 24 is a block diagram schematically showing the configuration of a conventional color laser printer. In the figure, a color laser printer includes an interface unit 1002 for inputting an output of a host computer 1001, a central processing unit (CPU) 1003, and a RAM (Random A).
access memory) 1004, a frame buffer memory 1005, a print control device 1006,
It comprises a YMCK printing unit 1007 and a bus line 1008.

Coded data generated by the host computer 1001 passes through an interface 1002 and is stored in a RAM 1004 via a bus line 1008. The data is converted by a CPU 1003 into bitmap data corresponding to Y, M, C, and K. After that, it is stored in the frame buffer memory 1005. The stored MCKY data is sent to the YMCK printing unit 1 by the print controller 1006.
007 are sequentially transferred and printed out via the YMCK printing unit 1007. The YMCK printing unit 1007 has a general configuration, and sequentially prints YMCK data for each sheet.

In recent years, some color printers employ a tandem system capable of high-speed printing as compared with a single system in which printing of a plurality of colors is performed by a single photosensitive member. The tandem system of the image output unit is provided with a paper transport mechanism for transporting paper in a fixed direction, a frame memory for storing one frame of output image for each color, and a predetermined interval along the paper transport path. It is composed of a plurality of printing units for performing one-color printing.

A functional feature of the tandem-type image output device is that printing is performed simultaneously and in parallel for each color, and printing is completed in one pass. The photoconductors of each color are sequentially arranged at predetermined intervals with respect to the transport path. Therefore, there is a difference in the transfer start time of each color depending on the interval between the photoconductors of each color, and it is necessary to adjust the print time difference. Here, in the case where the photoconductors are arranged in the order of YMCK in the paper transport direction, the transfer start time of the transfer process for each color is shown in a time chart below.

FIG. 25 is a time chart showing a transfer start time difference in the tandem transfer process. The photoconductor is YMC
When the sheets are arranged in the order of K, the transfer of the Y toner image is first performed on the sheet, and subsequently, M,
The transfer of the C and K toner images is sequentially performed. A buffer for storing raster image data for each color of YMCK until the start of transfer, separately from the RAM used in the printer, due to the time lag of the transfer of the toner image for each photoconductor of each color arranged in parallel. A memory is prepared for each color, and at the start of transfer of each color, raster image data is output as a toner image from a buffer memory to perform transfer.

In recent years, in order to reduce the buffer memory for each color under cost reduction, raster image data is divided into bands in the scanning direction so as to correspond to the distance between the photoconductors of each color, and the band is generated. Data is now handled on a case-by-case basis. The handling of data for each band has been adopted in many print processing methods.

For example, Japanese Patent Application Laid-Open No. 8-192542 discloses a color image forming apparatus using a technique for reducing the required memory content when a tandem system is used as a color printer for a workstation. According to this color image forming apparatus, coded data sent from a workstation is stored in a disk device, and the stored coded data is converted into raster image data for each color by a central processing unit. And stores the data of each of the YMCKs of a plurality of pages in the frame buffer memory. The data for each color is transferred to the Y intermediate memory buffer, the M intermediate memory buffer, the C intermediate memory buffer, and the K intermediate memory buffer in band units via the system bus. The YMCK data is transferred in parallel according to the printing speed of the printing unit.

Japanese Patent Application Laid-Open No. Hei 6-227049 discloses a color image forming apparatus using a technique of reducing the page memory capacity to one page. According to this color image forming apparatus, page description language (PDL) data input from the interface circuit is temporarily stored in the RAM. The stored data is stored in ROM by the central processing unit.
By executing the program read from (Read Only Memory), the data is converted into bitmap data before color conversion. The bitmap data before color conversion is divided into bands and stored in each page memory.
Further, the video interface circuit reads the stored bitmap data from the head address of the page memory designated by the central processing unit, performs color conversion for each color, and outputs a YMCK video signal to the image output device. .

[0011]

However, when the print processing method in the color image forming apparatus described in Japanese Patent Application Laid-Open No. 8-192542 is used, the total buffer memory used for each color is relatively small. However, high speed is required for data transfer using a bus connecting the disk device and the buffer memory, and high speed is also required for the read performance of the disk device itself, which leads to an increase in cost. was there.

According to the print processing method described in JP-A-6-227049, a buffer memory for storing bitmap data needs at least one page, and the resolution of the image output device is 600 DPI (dots).
per inch) and 1200 DPI, which leads to a significant cost increase.

SUMMARY OF THE INVENTION The present invention has been made in view of the foregoing, and has been made in consideration of the above-described problems, and is intended to transfer a toner image for each color photoconductor arranged in parallel to a tandem type full-color image output device having a plurality of photoconductors. An object of the present invention is to provide a print processing apparatus that efficiently absorbs a start time lag.

[0014]

According to the present invention, in order to solve the above-mentioned problem, n color components of print data are individually expanded and processed from image data to n individual image forming units. In a print processing apparatus for a tandem-type color image output apparatus that forms one full-color image by forming an image of a component, a print described by a predetermined drawing instruction that describes a drawing element of a character, a figure, and an image Print data input means for inputting data, intermediate data generating means for dividing drawing elements included in the print data for each band region and converting the data into an intermediate data format,
Intermediate data storage means for storing the intermediate data generated by the intermediate data generation means for each band area in page units, and the intermediate data input from the intermediate data storage means for n images of the color image output device Intermediate data buffer means for storing a capacity determined based on the number of bands corresponding to the largest distance between the forming units, and the intermediate data to be developed and drawn in a time series according to the distance between the n image forming units Input from the intermediate data buffer means for rendering and drawing, and n intermediate data developing means for outputting image data corresponding to individual color components to n image forming units of the color image output device; And a print processing apparatus provided with:

According to such a print processing apparatus, the print data input to the print data input means is input to the intermediate data generating means, where the drawing elements included in the print data are divided for each band area, Intermediate data converted to a generic data format is generated. The generated intermediate data is stored in the intermediate data storage means for each band area in page units. The intermediate data buffer means sequentially writes the intermediate data stored in the intermediate data storage means for each band area in page units. The intermediate data written in the intermediate data buffer is sequentially read into n intermediate data developing units in a time series according to the distance between the image forming units, and is developed for each color component. The developed image data is output to the image forming unit of the corresponding color component of the color image output unit.

Here, in the intermediate data buffer means, the same intermediate data is read out n times by n intermediate data developing means according to a time series corresponding to the distance between the image forming units. After the end, the intermediate data of the band becomes unnecessary, so that the intermediate data newly developed from the intermediate data storage means is written in the buffer area of the band. This makes it possible to efficiently absorb the image formation start time lag for each image forming unit of each color arranged in parallel, so that the intermediate data buffer means has one page of data in an intermediate data format with a high degree of abstraction. Because
The memory capacity can be reduced.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram showing the principle of a print processing apparatus according to the present invention. The print processing apparatus according to the present invention includes:
The present invention is applied to a tandem-type color image output unit 6 for forming one full-color image on a recording medium by sequentially forming n color images in n image forming units. Print data input means 1, intermediate data generation means 2, intermediate data storage means 3, intermediate data buffer means 4, and n intermediate data development means 5a.
To 5n.

The print data input means 1 includes characters, figures,
Print data described by a predetermined drawing command that describes a drawing element such as an image is input. The print data input to the print data input unit 1 is input to the intermediate data generation unit 2, and the intermediate data generation unit 2 divides the drawing elements included in the print data for each band area and converts them into an intermediate data format. Is done. This intermediate data generating means 2
The intermediate data generated in step (1) is input to the intermediate data storage means 3 and stored in page units for each band area. The intermediate data buffer means 4 stores the intermediate data from the intermediate data storage means 3 by a capacity determined based on the number of bands corresponding to the largest distance between the plurality of image forming units of the color image output means 6, It is written for each band area in units. The intermediate data written in the intermediate data buffer means 4 is composed of n intermediate data developing means 5a to 5
n are sequentially read and expanded for each color component. These intermediate data developing means 5a to 5n are provided with color image output means 6
And develops intermediate data read from the intermediate data buffer means 4 into bitmap image data of each color component,
The image data of each color component is output to the corresponding color component image forming unit.

Writing and reading of the intermediate data to and from the intermediate data buffer means 4 is managed as a ring buffer in band units, and is read out by the intermediate data developing means 5n which reads the intermediate data last among a plurality of intermediate data developing means 5a to 5n. Immediately thereafter, intermediate data to be newly developed from the intermediate data storage means 3 is written into the buffer area read by the intermediate data developing means 5n.

Next, the print processing method of the present invention is applied to four colors (YM
An embodiment in which the printing unit of (CK) is applied to a tandem-type full-color printing processing system arranged along the sheet conveyance direction will be described.

FIG. 2 is a block diagram showing an example of the configuration of the print processing system. In FIG. 2, the print processing system is roughly divided into three blocks. One is an output asynchronous processing unit 11, one is an output synchronous processing unit 12, and one is a pre-deployment processing unit 13. The output asynchronous processing unit 11 includes a document creation unit 14, a spool unit 15, and a lexical interpretation unit 1.
6, an intermediate data generation unit 17 and an intermediate data storage unit 18, which operate asynchronously with the output synchronization processing unit 12. The document creation unit 14 is realized on, for example, a client host computer, and the spool unit 15, the lexical interpretation unit 16, the intermediate data generation unit 17, and the intermediate data storage unit 18 are realized on, for example, a server host computer. The unit 15 is connected, for example, by a network. The processing in the output asynchronous processing unit 11 is performed asynchronously with the processing in the output synchronous processing unit 12 by storing the processing result in a storage device. The output synchronization processing unit 12 includes the temporary storage unit 1
9, an expansion processing unit 20, and an output unit 21.
And a dedicated hardware processing device that performs processing in synchronization with the hardware. In addition, the pre-deployment processing unit 13 uses a storage unit inside the output synchronization processing unit 12 to perform asynchronous processing with the output unit 21 in some cases, and to perform synchronization with the output unit 21 in some cases. This is a dedicated hardware processing device that performs various processing.

In the output asynchronous processing unit 11, the document creation unit 14 converts print data described in a description language from document data generated by an application program for processing document creation and editing in a personal computer or a workstation. It has a function to create. The description language targeted in the present embodiment is, for example, GDI (Graphical Device).
e Interface, trademark of Microsoft Corporation), Acrobat (Portable Doc) represented by Acrobat (trademark of Adobe Systems).
document Format), PostScript
(Page description language) such as Adobe Systems, Inc.
uage).

The spool section 15 is provided for the document creation section 1
Communication function for inputting the print data generated in step 4,
Alternatively, it has a function of temporarily storing print data until the print data is output to the lexical interpretation unit 16.

The lexical interpretation unit 16 cuts out the print data input from the spool unit 15 as a token in accordance with the syntax of a predetermined description language, and outputs the token to the intermediate data generation unit 17.

The intermediate data generation unit 17 includes a lexical interpretation unit 16
Receives and interprets the token output from the CPU, executes a rendering command, generates intermediate data in the form of a trapezoid as a basic unit for each rendering command, and stores the intermediate data in the intermediate data storage unit 18 or the temporary storage unit 19 of the output synchronization processing unit 12. send. The purpose of generating the intermediate data is to enable high-speed expansion processing synchronized with the output unit 21 in the expansion processing unit 20,
This is to ensure that the development processing time in is completed within a predetermined time. For this reason, the intermediate data is simplified so that the drawing time can be predicted.

The intermediate data storage unit 18 stores the intermediate data input from the intermediate data generation unit 17 for one page for each band, and sends out the intermediate data one band at a time in response to a request from the temporary storage unit 19. .

In the output synchronization processing section 12, a temporary storage section 19 is a buffer for temporarily storing a part of the intermediate data stored in the intermediate data storage section 18. The expansion processing unit 20 inputs the intermediate data temporarily stored in the temporary storage unit 19, and synchronizes with the output processing of the output unit 21.
The output unit 21 expands the output into bitmap data that can be directly printed and outputs the bitmap data.

The output unit 21 receives the print data output from the band buffer memory of the expansion processing unit 20,
It prints on recording paper and outputs it. More specifically, cyan (C), magenta (M), yellow (Y),
This is a color page printer using a laser scanning type electrophotographic system capable of performing exposure, development, and transfer in parallel for each black (B _k ) color and outputting a full-color image.
Next, as a configuration example of the output unit 21, a basic tandem-type color image forming apparatus using an electrophotographic system of a laser scanning system will be described.

FIG. 3 is a diagram showing the overall configuration of the color image forming apparatus. The color image forming apparatus includes a system control unit 2
11, the output of the expansion processing unit 20 and the system control unit 2
11, four interface units 212y, 212 connected to
12m, 212c, and 212k and four image data writing devices (Raster Output Scanner).
r; ROS) 213y, 213m, 213c, 213k
And four image forming units Y, M, C, and K corresponding to printing of four colors of cyan, magenta, yellow, and black.
And a paper transport unit that transports the paper.
Each image data writing device 213y, 213m, 213
Reference numerals c and 213k each include a polygon mirror that scans laser light under control of a controller (not shown) and a laser optical system, and a laser light irradiation window (not shown) is provided below the polygon mirror. The image forming units Y, M, C, and K of each color of the color image forming apparatus are arranged in this order in the sheet conveying direction. Image forming units Y, M,
Since C and K are the same in structure, here, only the yellow image forming unit Y will be mainly described. The image forming unit Y includes a drum-shaped photoconductor 214, a charger 21
5, developing unit 216, static elimination lamp 217, transfer unit 218,
It comprises a static eliminator 219 and a cleaning device 220. As the photoconductor 214, a photoconductive photoconductor and a dielectric can be used, and an organic photoconductor and a dielectric according to the material of the carrier can also be used. The paper transport section
It includes contact rollers 221 and 222, a charger 223, a transfer belt 224, a static eliminator 225, a roller unit 226, a belt cleaning unit 227, and a fixing unit 228.

The image data expanded by the expansion processing section 20 is input to the image data writing device 213y via the interface section 212y. Image data writing device 2
Reference numeral 13y is driven by a signal from the system control unit 211, and the image forming unit Y transfers image data. The image data writing device 213y uses an optical element such as an LD, an LED, and an LCD according to the characteristics of the photoconductor 214, and when the photoconductor 214 is a dielectric, uses direct writing such as ion flow to write the photoconductor 214 to the photoconductor 214. Form a latent image.

The photosensitive member 214 disposed below the image data writing device 213y is negatively charged by a charger 215 arranged as shown in the figure, and then a latent image is formed by the image data writing device 213y. Developing device 21 installed at a specific position around photoconductor 214
6 supplies toner to the photoconductor 214 on which the latent image has been formed,
The latent image formed on the photoconductor 214 is visualized as a toner image.

On the other hand, at the upstream end of the sheet transport section, a roller section 226 supporting the transfer belt 224 and a sheet 229
Downstream of the transfer direction of the transfer belt 224, a contact roller 222 for bringing the sheet 229 into close contact with the transfer belt 224, and a charger 223 disposed on the back surface of the transfer belt with respect to the roller. A suction device is provided for electrostatically attracting the sheet 229 to the transfer belt 224 by the suction device.

In the paper transport section, a belt cleaning section 227 including a cleaning brush and a blade is provided upstream of a roller section 226 supporting the transfer belt in the paper transport direction. Stain such as residual toner adhered to the surface is removed. The static eliminator 225 disposed upstream of the roller unit 226 in the transfer belt driving direction is for setting the potential of the transfer belt 224 to zero. The transfer belt 224 is
The charge for keeping the transfer roller 29 in close contact with the transfer belt 224 and the charge applied to the transfer belt 224 when transferring the toner image are removed by the charge remover 225, and then the belt cleaner 227 cleans the charge. The effect of holding another sheet is improved.

The toner image visualized on the photoreceptor 214 is irradiated with light from the neutralization lamp 217 to reduce the adhesion of the toner, and the transfer belt 218 is discharged by the transfer unit 218.
The image is transferred to the sheet 229 being conveyed by the reference numeral 24.
The toner remaining on the surface of the photoconductor 214 after the toner image is transferred to the paper 229 is discharged by the static eliminator 219 to the photoconductor 214.
After the residual potential of the photosensitive member 214 is reduced to zero, the photosensitive member 214 is removed by a cleaning device 221 disposed in the latter half of the rotation. Then, uniform charging is newly performed by the charger 215. When the process of the image forming unit Y is completed, the image forming unit M, the image forming unit C, and the image forming unit K transfer the remaining colors in the same process as the image forming unit Y.

In this way, the toner images of each color are transferred to the sheet 229 being conveyed by the transfer belt 224,
A desired toner image is formed on the sheet 229. Thereafter, the toner image is fixed on the paper 229 on which the toner image is formed by a fixing device 228 having two rollers. The fixing unit 228 melts the toner of the color image formed on the paper 229 by desired heat and pressure, thereby forming the paper 22.
9 to fix the transferred toner image.
A color image is printed on paper.

The outline of the print processing system has been described above. Next, details of a main part of the print processing system will be described. First, the details of the intermediate data generation unit 17 in the output asynchronous processing unit 11 will be described.

FIG. 4 is a block diagram showing a configuration example of the intermediate data generation unit. The intermediate data generation unit 17 includes a token interpretation unit 17a, an instruction execution unit 17b, an image processing unit 17c
Drawing state storage unit 17d, vector data generation unit 17
e, the font management unit 17f, and the matrix conversion unit 1
7g, a short vector generation unit 17h, a trapezoidal data generation unit 17i, a band decomposition unit 17j, a band management unit 17
k.

The token interpreter 17a is provided with a lexical interpreter 16
, And converts the token into an internal instruction and sends it to the instruction execution unit 17b. The command execution unit 17b transfers the command to the image processing unit 17c, the drawing state storage unit 17d, and the vector data generation unit 17e according to the command sent from the token interpretation unit 17a. The image processing unit 17c performs various types of image processing based on the input image header and image data, generates an output image header and output image data, and transfers the output image header and the output image data to the band decomposition unit 17j. The drawing state storage unit 17d stores information necessary for drawing given by a command from the command execution unit 17b. The vector data generation unit 17e generates vector data to be drawn using the command of the command execution unit 17b and information added thereto, information from the drawing state storage unit 17d, and information from the font management unit 17f. Transfer to the conversion unit 17g. Font management unit 17f
Manages and stores outline data of various fonts,
Provide character outline data on request. The matrix conversion unit 17g includes a vector data generation unit 17e.
Is affine-transformed by the conversion matrix of the drawing state storage unit 17d and transferred to the short vector generation unit 17h. Short vector generator 1
7h approximates the vector for the curve in the input vector with a plurality of straight line vector sets (short vectors), and sends it to the trapezoid data generation unit 17i. Trapezoid data generator 17i
Generates trapezoidal data to be drawn from the input short vector and transfers it to the band decomposition unit 17j. The band decomposing unit 17j divides the trapezoidal data over a plurality of bands from the input trapezoidal data into trapezoidal data of each band, and sends the trapezoidal data to the band management unit 17k in band units.
The band management unit 17k adds the management information and the color information input from the drawing state storage unit 17d and the image processing unit 17c to the trapezoidal data input for each band, and outputs the information to the intermediate data storage unit 18 as intermediate data. I do. It should be noted that the token interpreter 17a described above transmits the data from the intermediate data storage 1
The process up to writing to 8 is repeated each time a drawing command is input. The transfer of the intermediate data from the intermediate data storage unit 18 to the output synchronization processing unit 12 is performed after the intermediate data for one page is stored.

Hereinafter, the operation of each unit of the intermediate data generation unit 17 will be described in more detail while showing the actual data structure. The token interpreting unit 17a interprets the token input from the lexical interpreting unit 16, converts the token into an internal instruction or its argument, and converts a set of the internal instruction and the argument into an instruction executing unit 17b.
Transfer to For example, the internal commands include a drawing command for executing drawing of characters / graphics / images and a drawing state command for setting information necessary for drawing such as color and line attribute.

The instruction execution unit 17b includes a token interpretation unit 17
Execute the internal instruction sent from a. The commands executed here mainly include a drawing command and a drawing state command. For example, there are three types of drawing commands as shown in Table 1 below, and information necessary for each drawing is shown. Of these, the information with an underline is given as an argument in the drawing command, and the other information is stored in the drawing state storage unit 17d in advance by initial setting or a preceding command. In executing the drawing command, the received drawing command other than the image drawing is transferred to the vector data generating unit 17e as it is. In the case of image drawing, the received drawing command is transferred to the image processing unit 17c, and the vertical and horizontal sizes of the image header are determined by the vector data generating unit 17e.
Transfer to For the drawing state command, the command is transferred to the drawing state storage unit 17d.

[0041]

[Table 1]

The image processing unit 17c converts the input image header and the input image data, which are the arguments of the command input from the command execution unit 17b, using the conversion matrix and the color space information acquired from the drawing state storage unit 17d. A data structure to be output to the output synchronization processing unit 12 is generated and transferred to the band division unit 17j. This data structure will be described in detail in the following description of the trapezoidal data generation unit 17i.

The drawing state storage unit 17d stores the instruction execution unit 17
For example, the values of the information without the underline shown in Table 1 are set with the values of the arguments included in the instruction received from b, and the values are stored. The image processing unit 17
c, vector data generation unit 17e, matrix conversion unit 1
7g, short vector generation unit 17h, band decomposition unit 17
Transfer those values according to the request such as j.

The vector data generating unit 17e generates vector data for new drawing except for the solid drawing by using the command and argument sent from the command executing unit 17b and the value of the drawing state storage unit 17d. I do. First, the case of character drawing will be described. The character code given by the argument and the font ID obtained from the drawing state storage unit are transferred to the font management unit 17f to obtain character outline data. Since the acquired outline data does not include information on the drawing origin (current point), by adding the offset of the current point acquired from the drawing state storage unit 17d to the outline data,
Generate the desired vector data. In the case of image drawing,
A rectangular vector corresponding to the vertical and horizontal sizes of the image header given by the argument is generated, and the target vector data is generated by adding the offset of the current point acquired from the drawing state storage unit 17d. In the case of stroke drawing, the vector given by the argument and the drawing state storage unit 17d
An outline vector is generated from various line attributes acquired from.

FIG. 5 is an explanatory diagram of the outline vector. Two connected straight lines L by stroke drawing
1 and L2, the vector given by the argument of the center line indicated by the broken line and the drawing state storage unit 17d
An outline vector is generated from various line attributes of the contour data acquired from. That is, the center line and its thickness and 2
By specifying the process of connecting the straight lines L1 and L2 (in the illustrated example, a circle is arranged at the intersection of the center lines), an outline of a line having a thickness as shown in FIG. A vector is generated. The vector generated in this manner (in the case of the solid drawing, the vector directly received from the instruction execution unit 17b) is transferred to the matrix conversion unit 17g.

The font management unit 17f stores outline vector data for various fonts,
Based on the given character code and font ID, outline vector data for the character is provided.

The matrix conversion unit 17g affine-transforms the vector data received from the vector data generation unit 17e using the conversion matrix obtained from the drawing state storage unit 17d. The main purpose of the affine transformation is to convert the resolution (coordinate system) of the application to the resolution (coordinate system) of the printer. A 3 × 3 matrix as shown in the following equation (1) is used for the conversion matrix. The input vector data (Xn, Yn) is converted into output vector data (Xn ′, Yn ′), and the short vector generator It is sent to 17h.

[0048]

(Equation 1)

If the input vector includes a curve vector, the short vector generation unit 17h replaces the curve vector with the error fl obtained from the drawing state storage unit 17d.
A process of approximating with a plurality of short vectors is performed so as to be smaller than the attens value. This will be described with reference to FIG.

FIG. 6 is an explanatory diagram showing recursive division of a curve. For example, a Bezier curve represented by four control points indicated by black circles in FIG. 6 is used as a curve vector. In this case, in the process of converting into a short vector, the distance between the control points of the original Bezier curve indicated by black circles is divided into midpoints, and the division position is set as a new Bezier curve control point. This control point is indicated by a black square symbol. Furthermore, the Bezier curve can be represented by a plurality of shorter vectors by further dividing the distance between these control points into midpoints. In this way, the Bezier curve is recursively divided, and the division is terminated when the height (distance d) of the triangle formed by the divided control points becomes smaller than the value given by flatness. Then, by connecting the start point and the end point of each of the divided Bezier curves in order, the short vectorization is completed. The generated short vector is sent to the trapezoid data generator 17i.

The trapezoid data generation section 17i generates a set of trapezoid data indicating a drawing area from the input vector data. An example of generating trapezoid data from this vector data will be described with reference to FIG.

FIGS. 7A and 7B are explanatory diagrams for representing a polygon by trapezoidal data. FIG. 7A shows a state in which the polygon is divided into trapezoids, and FIG. 7B shows data representing the trapezoid. For example, a polygon vector indicated by a thick line shown in FIG. 7A is decomposed into four trapezoidal drawing areas by dividing each vertex by a horizontal line passing through the vertices. Therefore, these trapezoids are trapezoids having two sides parallel to the scan line of the output unit 21. One trapezoid is
As shown in FIG. 7B, the starting point coordinates (sx, s
y), base length (x0), distance (x1, x2) from x coordinate of both ends of the base to x coordinate of both ends of the top, and distance from y coordinate of bottom to y coordinate of top (H) -6
Data (sx, sy, x0, x1, x2, h). If the divided drawing area is a triangle,
Since the triangle is a trapezoidal special shape that satisfies the condition “x0 = x1 + x2”, the data structure is represented by the same data as the trapezoid. Next, the generated trapezoid data is sent to the band decomposition unit 17j.

The band decomposing unit 17j divides the trapezoidal data spanning a plurality of bands from the input trapezoidal data into trapezoidal data for each band, and transfers the trapezoidal data for each band to the band management unit 17k.

FIGS. 8A and 8B are explanatory diagrams of band division of trapezoidal data. FIG. 8A shows a state where a band boundary crosses the trapezoid, and FIG. 8B shows a trapezoid further divided at the band boundary. . According to FIG. 8, (A) shows the above-described polygon divided by four trapezoids, and indicates that two of the divided trapezoids are on the band boundary. In such a case, the band decomposition unit 17j divides the polygon consisting of the four trapezoid data at the band boundary, so that the polygon is divided into six trapezoid data as shown in FIG. .

The band management unit 17k generates intermediate data by adding additional information to the trapezoidal data input for each band, and writes the intermediate data to the intermediate data storage unit 18 for each band. Here, the additional information is management information for managing the intermediate data, and color information indicating in what color the trapezoid data is painted. The management information includes information related to the entire band and information different for each drawing object. The management information on the entire band is the data size of the intermediate data of the band. The management information for the character / graphic drawing command is an object ID.
(Identifier), the type of object, and the number of trapezoids. For example, the value of CMYK is color information.

FIG. 9 is a diagram showing an image generated by a drawing command and its intermediate data. FIG. 9A shows data for a character / graphic command, and FIG. 9B shows data for an image command. . First, a character / graphic drawing command is a command for drawing a deformed rectangle such as that shown in (A), and the rectangle is a trapezoid data generation unit 1.
It is assumed that the data is divided into three trapezoidal data by 7i. In the data format in this case, first, an object ID (OID) for identifying a square figure, an object type (OType) of a character or a figure, color information (Color), and information on the number of divided trapezoids are managed. Added as information,
The data of each trapezoid (sx, sy, x
0, x1, x2, h). The object ID contains a value incremented in the order of the drawing command, the type of the object contains the identifier of the graphic object, the color information contains the value of CMYK, and the number of trapezoids is "3" here.
Enters.

On the other hand, when the image generated by the image drawing command is a parallelogram as shown in FIG. 3B and is divided into three trapezoidal data, the data format is the object of the image. Management information includes data of ID (OID), image object (OType), and number of trapezoids. For each of the divided trapezoids, trapezoidal data (sx, sy, x0, x1, x2, h) and before development An image header RH including parameters for processing performed by the processing unit 13 and image data RD as color information are added. One image header RH and one image data RD are added to each of the trapezoidal data for each band generated by the drawing command. The image header RH is
If necessary, the image includes an affine transformation coefficient and a color space transformation coefficient for the image. The image header RH and the image data RD are input from the image processing unit 17c.

FIGS. 10A and 10B are diagrams showing image data added as intermediate data. FIG. 10A shows image data for the minimum rectangle of a vector, and FIG. 10B shows image data for the minimum rectangle of trapezoidal data. ing. Image header RH
And the image data RD are input from the image processing unit 17c, but the image data added as intermediate data is
This is image data corresponding to a minimum rectangle of a vector indicating an image converted as shown in FIG. The image processing unit 17
The image data converted by c is, as shown in (B),
Image data for the minimum rectangle for each trapezoid may be used. Further, since the image data has a large capacity, it may be stored in a compressed form.

The above trapezoidal data is grouped for each band, and EOD (End Of) is added to the final data of each band.
Data) is added to clarify the end of the band data.

Next, a more detailed configuration of the output synchronization processing section 12 will be described. FIG. 11 is a block diagram illustrating a configuration example of the output synchronization processing unit. 11, a temporary storage unit 19 includes a communication unit 19a, a work memory 19b, a work memory management unit 19c, and an intermediate data buffer management unit 1.
9 d and an intermediate data buffer unit 19 e, and the working memory management unit 19 c is connected to the pre-deployment processing unit 13. The expansion processing unit 20 includes a Y component expansion unit 20a
, An M component developing unit 20b, a C component developing unit 20c, and K
The output of each of these color component developing units is connected to an output unit 21 which is a tandem type color output device.

In the temporary storage section 19, the communication section 19a communicates with the intermediate data generation section 17 or the intermediate data storage section 18 and stores the intermediate data in the working memory 19b or the intermediate data buffer section 19e. In some cases, the data is output to the working memory management unit 19c or the intermediate data buffer management unit 19d.

The work memory 19b is a storage area used as a work area when the pre-decompression processing unit 13 performs, for example, decompression processing of compressed data. Working memory management unit 19c
Is the intermediate data generation unit 17 or the intermediate data storage unit 18
Communication between the work memory 19b and the work memory 19b, data communication between the work memory 19b and the pre-deployment processing unit 13,
It manages data communication between the working memory 19b and the intermediate data buffer 19e.

The intermediate data buffer section 19e comprises a buffer memory for temporarily storing intermediate data expanded by the expansion processing section 20. Intermediate data buffer management unit 19d
Is the intermediate data generation unit 17 or the intermediate data storage unit 18
Data communication between the data and the intermediate data buffer 19e;
It manages data communication between the intermediate data buffer unit 19e and the expansion processing unit 20, and data communication between the intermediate data buffer unit 19e and the work memory 19b.

In the expansion processing section 20, the Y component expansion section 2
0a, the M component developing unit 20b, the C component developing unit 20c, and the K component developing unit 20d each include an intermediate data buffer unit 19e.
The intermediate data to be expanded is read out from, the intermediate data is expanded, a corresponding color component is extracted, a video signal is generated, and the video signal is output to the output unit 21.

Next, the configuration and use of the intermediate data buffer 19e will be described. Intermediate data buffer unit 19
The logical configuration of e is a memory that can be accessed continuously or randomly in word units by one linear address space.

FIG. 12 is a diagram showing a state of the intermediate data buffer unit when the head of the paper is immediately before the photosensitive member of the Y component. In FIG. 12, the upper end of the intermediate data buffer unit 19e represents the start address 0 which is the first address to write the intermediate data, and the lower end represents the end address MADR which is the last address to write the intermediate data. When printing is to be performed, the intermediate data of YMCK is previously stored in the intermediate data buffer unit 19e from the intermediate data storage unit 18.
Is written up to, for example, address W1. When the head of the paper to be printed is moving immediately before the Y-component photoconductor 214, the Y-component developing unit 20a outputs the intermediate data buffer 1
The intermediate data to be developed is read from the start address 0 of the memory 9e. As described above, writing of the intermediate data to the intermediate data buffer unit 19e is always Y
This is performed before the component developing unit 20a reads out the intermediate data. The writing of the intermediate data and the reading of the intermediate data by the Y component developing unit 20a are performed for each band. Therefore, the intermediate data buffer unit 19e
Write at least one band is required for the preceding data to the intermediate data.

FIG. 13 is a diagram showing the state of the intermediate data buffer unit when the head of the paper is immediately before the photosensitive member of the M component. In FIG. 13, when the head of the paper to be printed is moving immediately before the photoconductor of the M component, the M component developing unit 20b
Reads the intermediate data to be developed from the start address 0 of the memory forming the intermediate data buffer unit 19e. Y
The component developing unit 20a reads intermediate data to be developed from the address RY2. When the M component developing unit 20b reads the intermediate data, the write address of the intermediate data from the intermediate data storage unit 18 precedes the address W2.

FIG. 14 is a diagram showing the state of the intermediate data buffer unit when the head of the paper is immediately before the photosensitive member of the C component. In FIG. 14, when the head of the paper to be printed is moving immediately before the photoconductor of the C component, the C component developing unit 20c
Reads the intermediate data to be developed from the start address 0 of the memory forming the intermediate data buffer unit 19e. M
The component developing unit 20b reads intermediate data to be developed from the address RM3. The Y component developing unit 20a reads intermediate data to be developed from the read address RY3. Further, the intermediate data from the intermediate data storage unit 18 is written to the address W3.

FIG. 15 is a diagram showing the state of the intermediate data buffer unit when the head of the paper is immediately before the K component photosensitive member. In FIG. 15, when the head of the paper to be printed is moving immediately before the photoconductor of the K component, the K component developing unit 20d
Reads the intermediate data to be developed from the start address 0 of the memory forming the intermediate data buffer unit 19e. C
The component developing unit 20c reads intermediate data to be developed from the start address RC4 of the memory forming the intermediate data buffer unit 19e. The M component developing unit 20b reads intermediate data to be developed from the read address RM4. The Y component developing unit 20a reads intermediate data to be developed from the read address RY4. Further, the intermediate data from the intermediate data storage unit 18 is written to the address W4.

FIG. 16 is a diagram showing the state of the intermediate data buffer section a little later than the state of FIG. As the writing of the intermediate data into the intermediate data buffer 19e proceeds, the address at which the intermediate data is written reaches the end address MADR of the intermediate data buffer 19e. At this time, since the K component developing unit 20d has finished reading the intermediate data, after that, the K component developing unit 20d of the intermediate data buffer unit 19e writes the intermediate data from the start address 0 where the reading has been completed. become.

FIG. 17 is a diagram showing a state of the intermediate data buffer section which has been further advanced from the state of FIG. When the Y component expansion unit 20a reaches the end address MADR of the intermediate data buffer unit 19e, the intermediate data from the intermediate data storage unit 18 has already been written from the start address 0 of the intermediate data buffer unit 19e. Returning to the start address 0 of the intermediate data buffer unit 19e,
The intermediate data is read from the start address 0. Also in the time after FIG. 17, the development processing unit for each color component repeats the same processing.

FIG. 18 is a diagram showing the state of the intermediate data buffer unit when the end of the paper to be printed is moving immediately after the Y-component photosensitive member. At this time, the Y component developing unit 20a has already completed the developing process. In FIG. 18, the address END is the address where the last intermediate data of the page being printed is stored. This address E
The intermediate data stored from ND to the intermediate data write address W6 is the intermediate data of the page to be printed next. Further, the address RM6 from which the M component developing unit 20b reads out the intermediate data, the address RC6 from which the C component developing unit 20c reads out the intermediate data, and the address RK6 from which the K component developing unit 20d reads out the intermediate data sequentially advance in the direction of END.

As described above with reference to FIGS. 12 to 18, the intermediate data buffer section 19e does not need to have a capacity for storing all the intermediate data of the entire page to be printed, but a capacity for storing a part thereof. I just need to bring it. here,
The capacity BSize of the intermediate data buffer 19e will be described. The capacity BSize is represented by the following equation.

[0074]

BSize = BS _YK + BSP (2) where BS _YK is the capacity of intermediate data corresponding to the physical distance D _YK between the Y component photoconductor 214 and the K component photoconductor.
BSP is the capacity of the buffer area for guaranteeing that the writing of the intermediate data is performed before the reading of the intermediate data by the Y component developing unit 20a. BS _YK
Is represented by the following equation.

[0075]

BS _YK = RS _wh × D _YK ÷ D _wh ÷ CRatio (3) where RS _wh is the capacity of video data with respect to the entire paper,
D _wh is the length of the paper in the direction in which the paper is conveyed by the transfer belt 224. CRatio is a compression ratio of bitmap (or video) data of intermediate data,
This is several tens to 100 times or more when trapezoidal data is used as intermediate data for characters and figures, and JPEG (Joint P
photographic Experts Grou
Since the compression rate varies depending on the adopted format, such as about 10 times when a cosine-transformed compression format such as p) is used, the minimum compression rate is
It must be adopted as the value of Ratio.

Next, the expansion processing section 20 will be described in detail. In the expansion processing unit 20, a Y component expansion unit 20a for expanding the Y component, an M component expansion unit 20b for expanding the M component, a C component expansion unit 20c for expanding the C component,
Since all the K component expansion units 20d for expanding the K component have the same configuration, the internal configuration and operation of the Y component expansion unit 20a will be described here as a representative.

FIG. 19 is a block diagram showing a configuration example of the Y component developing unit. The Y component developing unit 20 a
, A refresh control unit 202, an intermediate data transfer control unit 203, a print data transfer control unit 204, an arbitration unit 205, and a memory unit 206. The memory unit 206 includes two band buffers A207 and B208. And a work area 209.

The intermediate data buffer unit 1 of the temporary storage unit 19
The intermediate data stored in 9e is read into the drawing unit 201 by the intermediate data transfer control unit 203. Drawing unit 20
Reference numeral 1 denotes a band buffer A 207 or a band buffer B 20 of the memory 206 for expanding the input intermediate data.
Draw on 8. The print data transfer control unit 204 includes a band buffer A 207 or a band buffer
The print data expanded from 208 is read, and the read data is converted into serial data for each read data unit (word).
Output to the output unit 21 in synchronization with the serial output clock signal. The refresh control unit 202 controls the band buffer A
207, band buffer B208 and work area 20
9 is refresh-controlled. The arbitration unit 205 includes a drawing unit 201, a refresh control unit 202, an intermediate data transfer control unit 203, and a print data transfer control unit 204, each of which is a memory unit 2.
When accessing 06, arbitration control is performed according to the access priority of each block.

A method of using the two band buffers A 207 and B 208 will be described. When the rendering unit 201 renders intermediate data for a certain band i in one band buffer, the other band buffer stores the rendered bitmap data for the previous band (i-1). The data transfer control unit 204 reads out the data from this and outputs a video signal to the output unit 21. This print data transfer control unit 20
When the output of the video signal by the control unit 4 is completed, the roles of the two band buffers A207 and B208 are switched. One band buffer is used for data output by the print data transfer control unit 204, and the other band buffer is used for the next band buffer. Used for drawing band (i + 1).

The drawing unit 201 draws a trapezoidal area based on the input trapezoidal data (sx, sy, x0, x1, x2, h), and then the drawing unit 201
Will be described.

FIG. 20 is a block diagram showing a configuration example of the drawing unit, and FIG. 21 is an explanatory diagram showing trapezoid data converted by the drawing unit. The drawing unit 201 includes an intermediate data input unit 231 and
It comprises a coordinate calculation unit A232 and a coordinate calculation unit B233, and an edge drawing unit 234.

The drawing unit 201 stores trapezoidal data (sx, sy, x0, x1, x2, h) as input intermediate data.
Are converted to four points (P ₀ , P ₁ , P ₂ ,
It is converted into a data format consisting of P ₃₎ to draw a trapezoidal region. First, the intermediate data input unit 231 is
, And reads the data forming each trapezoid, and outputs the trapezoid data to the coordinate calculator A232 and the coordinate calculator B233. Coordinate calculation unit A232 is responsible for coordinate calculation of the trapezoidal left edge (the edge P ₀ -P _1), and outputs sequentially toward the coordinate value on the edge from P ₀ to P _1. Coordinate calculation section B233 is trapezoidal right edge (the edge P ₂ -P
Responsible for the coordinate calculation of _3), and outputs sequentially toward the coordinate value on the edge from P ₂ to P _3. The edge drawing unit 234
A straight line parallel to the x-axis of the trapezoid is drawn based on the coordinate values input from the coordinate calculation unit A232 and the coordinate calculation unit B233.

Here, the detailed configurations of the coordinate calculator A232, the coordinate calculator B233, and the edge drawing unit 234 will be described below. First, since the coordinate calculator A232 and the coordinate calculator B233 have the same configuration, only one of them will be described as a representative.

FIG. 22 is a block diagram showing a configuration example of the coordinate calculation unit. The coordinate calculation unit is a DDA (Digital
(Differential Analyzer) parameter calculator 241, DDA processor 242, and coordinate updater 243.

The DDA parameter calculator 241 converts the input trapezoidal data (sx, sy, x0, x1, x2, h) into four points of trapezoidal data (P ₀ , P ₁ , P ₂ , P ₃ ). And DDA parameters such as initial values of slope and residual (first-order difference coefficient used for calculating the coordinates of a straight line) are calculated.
Output to the A processing unit 242. The DDA processing unit 242 performs DDA processing based on the input parameters, and outputs a moving direction and a moving amount with respect to the last obtained point. The coordinate updating unit 243 updates the currently held coordinate values based on the input movement direction and movement amount, and outputs the updated coordinate values. It is assumed that the initial values of the coordinates are set in advance by a CPU (not shown) or the like.

FIG. 23 is a block diagram showing a configuration example of the edge drawing section. The edge drawing unit 234 inputs the coordinate values A / B and the image data and paints the trapezoidal internal region. The address drawing unit 251 and the mask calculation unit 252
, A data operation unit 253, and RmodW (Read m
modify and write) processing unit 254.

The address calculator 251 receives the coordinate values A / B and calculates the address of the edge component to be drawn.
The mask calculation unit 252 inputs the values of the coordinate values A / B,
Outputs a mask representing valid bits in the word to be drawn. The data operation unit 253 determines that the input data is a character /
In the case of a figure, color data representing a fixed color by a trapezoidal area is input, and screen processing is performed using this value to output. If the input data is image data, screen processing is performed on the input image data and the image data is output.
The RmodW processing unit 254 performs drawing by performing the following processing using the input address, mask, and data. First, the band buffer is read by the address. Assuming that the read data is Source, the mask data is Mask, and the drawing data is Data, (Mask * Data + Mask # * Source)
Calculate the value of e) and write it back to the same address. However,
* Indicates logical product, + indicates logical sum, and # indicates logical negation. This process is repeatedly performed for each word including the edge to be drawn.

[0088]

As described above, according to the present invention, intermediate data buffer means for temporarily storing one page of intermediate data is provided before developing intermediate data generated from print data for each color component. The written intermediate data is read out by the intermediate data developing means in a time series according to the distance between the image forming units, and after the last intermediate data developing means finishes reading, the intermediate data is newly developed in the area where the intermediate data was written. The intermediate data to be written is written from the intermediate data storage means. Thus, the image formation start time lag for each image forming unit (photoconductor) of each color arranged in parallel can be efficiently absorbed, and the intermediate data buffer means has the data for one page. In addition, the memory capacity is reduced, and the cost of the memory can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing the principle of a print processing apparatus according to the present invention.

FIG. 2 is a block diagram illustrating a configuration example of a print processing system.

FIG. 3 is a diagram illustrating an overall configuration of a color image forming apparatus.

FIG. 4 is a block diagram illustrating a configuration example of an intermediate data generation unit.

FIG. 5 is an explanatory diagram of an outline vector.

FIG. 6 is an explanatory diagram showing recursive division of a curve.

FIGS. 7A and 7B are explanatory diagrams illustrating polygons represented by trapezoidal data, wherein FIG.
(B) shows data representing a trapezoid.

FIG. 8 is an explanatory diagram of band division of trapezoidal data,
(A) shows a state where the band boundary crosses the trapezoid,
(B) shows a trapezoid further divided at the band boundary.

9A and 9B are diagrams showing an image generated by a drawing command and intermediate data thereof, wherein FIG. 9A shows data for a character / graphic command and FIG. 9B shows data for an image command.

10A and 10B are diagrams showing image data added as intermediate data, wherein FIG. 10A shows image data for a minimum rectangle of a vector, and FIG. 10B shows image data for a minimum rectangle of trapezoidal data. .

FIG. 11 is a block diagram illustrating a configuration example of an output synchronization processing unit.

FIG. 12 is a diagram illustrating a state of the intermediate data buffer unit when the head of the paper is immediately before the photoconductor of the Y component.

FIG. 13 is a diagram illustrating a state of the intermediate data buffer unit when the head of the paper is immediately before the photoconductor of the M component.

FIG. 14 is a diagram illustrating a state of the intermediate data buffer unit when the head of the paper is immediately before the photosensitive member of the C component.

FIG. 15 is a diagram illustrating a state of the intermediate data buffer unit when the head of the paper is immediately before the photoconductor of the K component.

FIG. 16 is a diagram showing a state of the intermediate data buffer unit a little later than the state of FIG. 15;

FIG. 17 is a diagram showing a state of the intermediate data buffer section further advanced from the state of FIG. 16;

FIG. 18 is a diagram illustrating a state of the intermediate data buffer unit when the end of the paper to be printed is moving immediately after the Y-component photoconductor.

FIG. 19 is a block diagram illustrating a configuration example of a Y component developing unit.

FIG. 20 is a block diagram illustrating a configuration example of a drawing unit.

FIG. 21 is an explanatory diagram showing trapezoid data converted by a drawing unit.

FIG. 22 is a block diagram illustrating a configuration example of a coordinate calculation unit.

FIG. 23 is a block diagram illustrating a configuration example of an edge drawing unit.

FIG. 24 is a block diagram schematically showing a configuration of a conventional color laser printer.

FIG. 25 is a time chart showing a transfer start time difference in the tandem transfer process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Print data input means 2 Intermediate data generation means 3 Intermediate data storage means 4 Intermediate data buffer means 5a to 5n Intermediate data development means 6 Color image output means

Claims (4)

[Claims] 1. An image forming unit in which n color components of print data are individually expanded and processed to form one full-color image by forming an image of each color component in an image forming unit arranged side by side. In a print processing device for a tandem-type color image output device, a print data input unit for inputting print data described by a predetermined drawing command that describes a drawing element of a character, a figure, or an image; Intermediate data generating means for dividing drawing elements to be drawn for each band area and converting the data into an intermediate data format, and intermediate data storing means for storing the intermediate data generated by the intermediate data generating means for each band area in page units And the largest intermediate data input from the intermediate data storage means between the n image forming units of the color image output device. Intermediate data buffer means for storing a capacity determined based on the number of bands corresponding to the separation, and the intermediate data buffer means for storing the intermediate data to be developed and drawn in a time series according to the distance between the n image forming units And an intermediate data expanding unit that outputs image data corresponding to each color component to the n image forming units of the color image output apparatus. Print processing device. 2. The printing process according to claim 1, wherein the intermediate data buffer means determines the maximum capacity of the stored intermediate data by a minimum compression ratio of the intermediate data to the image data. apparatus. 3. The n intermediate data developing means reads the same intermediate data written in the intermediate data buffer means in a time series according to a distance between the n image forming units, and reads the n intermediate data. The print processing apparatus according to claim 1, wherein image data corresponding to a print color corresponding to the image forming unit is generated. 4. The method according to claim 1, wherein the intermediate data buffer means includes the n data buffer.
Immediately after the intermediate data expanding unit that reads the intermediate data among the intermediate data expanding units reads the intermediate data, the intermediate data to be newly expanded from the intermediate data storing unit is written to the buffer area that has been finally read. 2. The print processing apparatus according to claim 1, wherein the print processing is managed as a ring buffer in band units.