JPH04148949A - Vector image printing apparatus - Google Patents

Abstract

PURPOSE:To accurately reproduce the impression of a vector image without damaging the effect of anti-aliasing processing by inputting image data and characteristic data in synchronous relationship and selecting the printing system of a multivalue printer so as to print the image data concerned in the optimum state on the basis of the characteristic data. CONSTITUTION:A printing system selection means 30 inputs the image data stored in an image data memory means 10 and the characteristic data stored in a characteristic data memory means 20 in synchronous relationship and outputs the edge part pixel concerned to a photosensitive body 50 using a power modulation system in the case of characteristic data '0' and outputs the edge part pixel concerned to the photosensitive body 50 using a pulse width modulation system in the case of characteristic data '1'. In other words, in the case of vector data whose inclination is 45 deg. or more and a right edge, the edge part pixel concerned is outputted as a vertically oblong dot and in after cases as a horizontally oblong dot to print image data in the optimum state.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a vector image printing device that develops a hector image into image data and prints it with a multilevel printer. This invention relates to an image printing device that enables optimal printing.

[Conventional technology]

In the field of computer graphics, when displaying an image on a CRT, which is an output medium, a technique called anti-aliasing processing is used to make the displayed image more beautiful. This process applies brightness modulation to the jagged part (called alias) of the second staircase as shown in Fig. 22(a), and visually changes the displayed image as shown in Fig. 22(b).
) as shown in the figure.

In conventional graphic processing apparatuses, (1) uniform averaging method, (2) weighted averaging method, (2) convolution integral method, etc. are generally applied as anti-aliasing processing methods.

■The uniform averaging method calculates each pixel by N*M (N,
After decomposing the image into sub-vixels (M is a natural number) and performing rask calculation at high resolution, the luminance of each pixel is determined by taking the average of N*M sub-pixels. Figure 23(a)
, (b), anti-aliasing processing using the uniform averaging method will be specifically explained. If the edge of the image overlaps a certain pixel (here, it is assumed that the image is connected to the lower right of the diagonal line), and when anti-aliasing processing is not performed, as shown in Figure (a),
The brightness kid of this pixel is assigned the highest brightness of the displayable gradations (for example, kid·255 for 256 gradations). When performing anti-aliasing processing on this pixel by the uniform averaging method of N=M-7, the same figure (
As shown in b), the vixel is decomposed into 7*7 sub-vixels, and the number of sub-vixels covered by the image is counted. The brightness of that pixel is calculated by dividing the count number (28) by the total number of sub-vixels in one pixel (49 in this case) and multiplying the normalized (averaged) result by the maximum brightness (255). In this way, in the uniform averaging method, the brightness of each pixel is determined by taking into consideration how the image covers each pixel.

■Weighting is an averaging method The weighting and averaging method is a partial modification of the uniform averaging method. In contrast to the weighting method, which simply counts the number of sub-vixels in the image, the averaging method assigns a weight to each sub-vixel, so that the influence on the brightness kid of that sub-vixel differs depending on which sub-vixel the image falls on. I have to. Note that the weight at this time is given using a filter.

With reference to FIGS. 24(a) and (b), FIG. 23(a)
An example is shown in which the same image data is weighted using the same dividing method (N=M=7) and the averaging method.

FIG. 24(a) shows a filter (here, conef
ilter), and the corresponding sub-vixel is given the same weight as this characteristic. For example, the weight of the sub-vixel in the upper right corner is 2. If an image is applied to each Zab Bixel, the heavier value given by the filter characteristics will be the direct value of that Zab Bixel. The same figure (b
) shows the display pattern of the image changed depending on the weight of the sub-vixels. In this case, when the weighted sub-vixels of the image are added to Callan 1, the result is 199. This value is averaged by dividing it by the sum of the filter values (336 in this case) corresponding to the uniform averaging, and multiplied by the maximum brightness to calculate the brightness of this pixel. In addition, as a filter, FIG. 25(a),
(b), (c), (d) are well known.

■Convolution Integration Method The convolution integration method is a method that refers to the appearance of surrounding pixels when determining the brightness of one pixel. That is, the area around one pixel whose brightness is to be determined is N
It is assumed that the 'XN' pixel corresponds to the pixel of the equal-averaging method or the weighting/averaging method. 26th
The figure shows a convolution method with 3×3 pixel references. In this figure, the pixel whose brightness is to be determined is 2601
Indicated by The image continues to the bottom right of the diagonal line, and the sub-vixels painted in black are the sub-vixels that are counted.

Each pixel is divided into 4*4. Therefore, in this case, a 12*12 filter will be used. This method has the effect of removing high frequency components contained in a vector image.

On the other hand, a publishing system using a personal computer,
So-called DTP (Desk 1-Publishing)
With the spread of computer graphics, vector image printing devices that print vector images such as those used in computer graphics have come into wide use. As a vector image printed by a vector image printing device, for example, there is one using Adobe's Post Script. Bost Script is a page description language (Page Descriptor).
on Language: Hereafter, P D 1. It belongs to a language genre called ``Document 1-'', and includes the text (letter part) and graphics included in it, as well as their arrangement and format. It is a programming language for writing, and uses VectorFmento as the character font. Therefore, with a vector image printing device that prints vector images, even if the characters are scaled, the printing quality is significantly improved compared to when a human map font is used (for example, a conventional word processor). 1: Another advantage is that character fonts, graphics, and images can be mixed and printed.

However, the resolution of the multilevel laser printer used in these vector image printing devices is 240 dp at most.
Many of them have a resolution of i to 400 clpi, and like CRT displays of computer graphics, there is a problem in that aliasing occurs due to the low resolution. For this reason, even in printing using a hexagonal image printing device, anti-aliasing processing is performed to improve the quality of the printed image.

Further, as a printing method of a multilevel laser printer in a vector image printing device, a power modulation method and a pulse modulation method are generally used.

[Problem to be solved by the invention]

However, vector image printing devices that use the power modulation method use dots with a constant length in the main scanning direction, and change the density (gradation value) by changing the thickness of the dots. For example, the electrostatic latent images of vector images A and B CDE, which are not shown in FIG.
)), and as shown in the figure, there was a problem in that the portion surrounded by the broken line was formed with a different impression from the original vector image ABCDE.

On the other hand, vector image printing devices that use the pulse modulation method use vertically elongated dots with the left end of the pixel as the starting point, and change the density (gradation value) by changing the length of this dot in the main scanning direction. For example, Fig. 27 (
The electrostatic latent image of vector image ABCDE shown in a) is shown in the same figure (
As shown in C), there was a problem in that the portion surrounded by the broken line was formed with a different impression from the original hector image ABCDE as shown in the figure.

Also, in the pulse width modulation method, dots with low density are formed at positions on the left side of the figure, so the density in that area becomes even thinner, and the effect of anti-aliasing processing is not fully realized. There was also a problem.

The present invention has been made in view of the above, and an object of the present invention is to accurately reproduce the impression of a vector image without impairing the effect of anti-aliasing processing.

[Means for solving the problem] In order to achieve the above object, the present invention utilizes DTP (desk
A vector image printing device that uses anti-aliasing processing to develop a vector image created by a company such as Top Publishing) into image data, performs predetermined image processing, and then prints it on a multilevel printer. an image data storage means for storing applied image data; a feature information storage means for storing feature information of the image data; image data stored in the image data storage means; and features stored in the feature information storage means. Provided is a vector image printing device equipped with a printing method selection means that inputs information in synchronization and selects a printing method of a multilevel printer so that corresponding image data is printed in an optimal state based on characteristic information. It is something to do.

[Effect]

In the vector image printing device of the present invention, the image data stored in the image data storage means and the feature information stored in the feature information storage means are synchronously input to the printing method selection means, and the feature information is Based on this, the printing method of the multilevel printer is selected so that the corresponding image data is printed in an optimal state.

〔Example〕

Hereinafter, an image forming system to which the vector image printing device of the present invention is applied will be described as an example. ■Outline of the present invention; ■Block diagram of the image forming system; ■Configuration and operation of the PDL controller; ■Configuration and operation of the image processing device. , ■The configuration and operation of a multivalued color laser printer, and ■The multivalued drive of the driver will be explained in detail in this order.

■Overview of the present invention First, the schematic configuration of the hector image printing apparatus of the present invention will be explained with reference to FIG.

In FIG. 1, 10 is an image data storage means for storing image data subjected to anti-aliasing processing, and 20 is characteristic information of the image data (details will be described later).
The feature information storage means 30 stores the image data stored in the image data storage means 10 and the feature information stored in the feature information storage means 20 in synchronization, and based on the feature information, Printing method selection means for selecting a driving method (printing method) of the multilevel printer so that the corresponding image data is printed in an optimal state; 40, a laser diode for outputting a laser beam; 50, a device for forming a latent image; Photoreceptor ■ is shown.

Here, in the feature information storage means 20, if the vector data has an inclination of 45 degrees or more and is a right edge, "1" is stored in advance as the feature information of the corresponding pixel; otherwise, "1" is stored as the feature information of the corresponding pixel. “0” is stored as pixel feature information.

In this embodiment, the slope information of the vector data and the type of edge (whether the edge pixel is on the right or left side of the figure) are used as feature information, but the present invention is not limited thereto. Furthermore, the method of setting the feature information is not limited to this.

In the above configuration, the printing method selection means 30 synchronizes and inputs the image data stored in the image data storage means 10 and the feature information stored in the feature information storage means 20, and the feature information is 0'', the corresponding edge pixel is applied to the photoreceptor 50 using a power modulation method.
If the feature information is "1", the corresponding edge pixel is output to the photoreceptor 50 using the pulse modulation method.

In other words, if the slope of the vector data is 45 degrees or more and it is a right edge, the corresponding edge pixel is output as a vertically long dot; otherwise, the corresponding edge pixel is output as a horizontally long dot. to print the image data in the optimal condition.

■Block diagram of image forming system The image forming system of this embodiment is DTr' (desk/I
-Page Description Lang% output from Tsubu Publishing)
This configuration is capable of image formation of image information of both hector data written in PDI language (hereinafter referred to as PDI language) and image images read by an image reading device. The configuration of the image forming system J of this embodiment will be described below with reference to FIG.

The image forming system 1, the host computer 1 which creates a document written in the PDL language (in this embodiment, the BostScrib 1 language is used), and the host computer 100 sent in pages from the host computer 100. P [1■-
Anti-aliasing the g word and changing it from 2 to red (
A PDL controller 200 that develops images in three colors: R), green (G), and blue (B), and an image reading device 30 that reads image information via an optical system unit.
0, PDL controller 200. Alternatively, an image processing device 400 that inputs the image output from the image reading device 300 and performs multi-value gradation processing, etc., and a multi-value color laser that prints the multi-value image data output from the image processing device 400.・Printer 500, PDL controller 2001, image reading device 300°, image processing device 40
0. and a system control section 600 that controls the multivalued color laser printer 500.

■Configuration and operation of PDL controller FIG. 3 shows the configuration of the PDL controller 200, which includes a receiving device 201 that receives the PDL language sent from the post computer 100, and a storage device for the PDL language received by the receiving device 201. A CPU 202 that performs control and anti-aliasing processing, and an internal system bus 20
3 and the receiving device 201 via the internal system bus 203.
RAM 204 that stores the PDL language to be transferred from
and RO that stores antialiasing programs, etc.
M205, a page memory 206 that stores multivalued RGB image data subjected to anti-aliasing processing, and a transmitting device 207 that transfers the RGB image data stored in the page memory 206 to the image processing device 400;
I10 device 20 that performs transmission and reception with the system control unit 600
It consists of 8.

Here, the CPU 202 receives the P received by the receiving device 201.
DL language is transmitted to RA, M2 through internal system bus 203 according to the program stored in ROM 205.
Store in O4. After that, when one page's worth of PDT-language is received and stored in the R, AM 204, anti-aliasing processing is applied to the graphic elements in the RA, M2O4 based on flowchart 1, which will be described later, and the multivalued ROB is The image data is stored in the brain memory section of the page memory 206.

As shown in FIG. 3(b), the page memory 206 includes a plain memory section 206a for R, G, and B, and a feature information storage memory section that stores feature information specifying the printing method of each pixel. 206b.

The data in the page memory 206 is then transferred to the transmitter 2
07 to the image processing device 400.

The operation of the PDL controller 200 will be described below with reference to FIGS. 4(a) and 4(b).

FIG. 4(a) shows a flowchart of processing performed by the CPU 202. As described above, the PDL controller 200 performs anti-aliasing processing on the PDL language sent page by page from the host computer 100, and converts it into red (R).

It is developed into three-color image data: green (G) and blue (B).

In the PDL language, graphics and characters are all described using vector data, and as the name "page description language" indicates, image information is processed in units of pages. Further, one page is made up of at least one bus, each of which is made up of one or more elements (graphic elements and character elements).

First, when the PDT-language is input, it is determined whether the element is a curved line vector, and if it is a curved vector, it is approximated to a straight line vector and registered as a straight line element (line) in the work area. This is performed for all graphic and character elements within one bus, and linear elements are registered in the work area for each bus (processing 1).

Then, the linear elements of the work area registered in this path unit are sorted by the starting X coordinate of the straight line (Processing 2
).

Next, in process 3, while updating the X coordinate one by one,
Performs filling processing using scanning lines. For example, in Figure 4 (
When performing the bus filling process shown in b), the elements on the side across which the scanning line yc to be processed and the real value of the X coordinate across the scanning line yc (x, χ2,
X4) and AET (8active Edge Tab
le: table for recording the X coordinate of the edge portion appearing on the scanning line). Here, the order of the elements registered in the work area is the order in which they were registered in process 1, so they are not necessarily registered in order of decreasing X coordinate across the scanning line yc. For example, in process 1, if a straight line element passing through scanning lines yc and X3 in FIG. 4 is processed first, X3 is first registered in AET as the be done.

Therefore, after the AET is registered, the elements on each side within the AET are sorted in descending order of X coordinate. Then, make the first two elements of AET bare and fill in the space between them.

Anti-aliasing processing In the filling process of a cigarette, this is achieved by adjusting the density and brightness of the pixels at the edges according to the approximate area ratio. Then, remove the processed edge from the AET, update the scanline (update the Repeat the process.

Above processing 1. Processing 2. The work in process 3 is executed pass by pass and repeated until all buses for one page are completed.

Next, the antialiasing process executed during the scan line filling process of process 3 described above will be described in detail with reference to the flowchart of FIG. 4(C).

Here, for example, in process 1 of FIG. 4(a),
), this figure has the following elements.

(B) Line vectors of the five trees AB, BC, CD, DE, and EA (represented by real numbers) (D) Color and brightness values inside the figure This figure is created as shown in Figure 5 (l) by the above-mentioned operation. The image is divided into seven straight line vectors (expressed as real numbers) extending in the main scanning direction. At this time, in this embodiment, the following information is added to the starting points and ending points of the seven straight line vectors.

That is, (c) Starting point coordinate values (real number expression) of the vector elements ((a) above) forming the starting point and ending point of the straight line vector (d) Slope information (near ) Information on the starting point and ending point of the straight line vector (right edge,
Left edge, end point of figure, ], line below F' cut,
(intersections of straight lines, etc.) In the scan line filling process,
) executes the anti-aliasing process shown in flowchart 1.

First, in subpixel filling processing, a filling area for each subpixel is calculated using a 3*3 subpixel division method (S401). This process is repeated for all vectors crossing the scanning line (S, 102).

Next, in the density determination process, the approximate area ratio of each pixel is calculated in order from the first pixel of the target scanning line using a filter of the uniform averaging method (anti-aliasing processing method) (S4.03 ).

Next, in the feature information setting process, the slope of the straight line vector is set to 45 based on the slope information of the straight line vector in (2) and the type of edge (right edge or not) in (e).
If the pixel is "more than" - and the right edge, "1" is set as the feature information of the corresponding pixel, and "0" is set as the feature information of the pixel in other cases (S404).

The gradation value (density) of each color (four colors of BKR and 02B) of the figure is calculated in the overwriting process described later.

Here, if the figure in FIG. 5(a) has a white background color (
The figure color is red (maximum brightness: 25) on top of
5), from the approximate area ratio k (see Figure 6), the brightness values Kr (red), Kg for each color of the figure
(green), (blue) are calculated based on the following formula.

K, = K,,X k 1KR2X(1-k)K9
= KGIXk +KG2X(1-k)Kb =
KBI × k -t KB□X(], -k
) However, K□, K, , I (II is respectively]
The color of the figure given in II (II) (respectively red, green,
□ indicates the luminance value of each previously painted color. Furthermore, KRz, Kcm
, KH2 refers to data in each plane memory section corresponding to RGB in the vegetable memory 206 (5405).

After that, in page memory drawing processing, the gradation value of each color is written to the plain memory section 206a of the page memory 206, and the feature information C is written to the feature information storage memory section 206b (
S406).

Furthermore, the processes from 5403 to 5406 described above are repeatedly executed for all pixels of one line (3407).

The CPU 202 repeats the above process up to the last pixel of the scanning line (y coordinate). The approximate area ratio of the figure in FIG. 5(a) obtained by the anti-aliasing process in this way has a value as shown in FIG. 6, and the feature information C of each pixel obtained by the feature information setting process is The values will be as shown in the figure.

In addition, the brightness values of the brightness values Kr1K, . is stored as RGB image data.

(2) Configuration of Image Processing Apparatus The configuration of the image processing apparatus 400 will be explained with reference to FIG. 9.

The image processing device 400 is a CC in the image reading device 300.
Black (BK) necessary for recording the three-color image signals read by D7r, 7g, and 7b.

Yellow (Y'), magenta (M), and cyan (C
) into each certified edition. In addition, the aforementioned PDL
Similarly, the RGB image data given from the controller 200 is divided into black (BK), yellow (Y),
It is converted into magenta (M) and cyan (C) recording signals. Here, the mote that inputs the image signal from the image reading device 300 is set to copy machine mode, PDL, :rnt D-
The mode in which RC;B image data is input from the controller 200 is called graphics mode.

Image processing device 400, CCD 7r, 7g, and 7b
The color gradation data obtained by A/D converting the output signal of 8 hints is input, and the optical illumination unevenness of the color gradation data
A shading correction circuit 40 that performs correction for variations in sensitivity of the internal 5III elements of 7r, 7g, and 7b.
1, and a multiplexer 4 that selectively outputs either the color gradation data output from the shading correction circuit 401 or the color gradation data (RC; B image data) output from the PDL controller 200 according to the above-described mode.
02, a γ correction circuit 403 that inputs the 8-bit data (color gradation data) output from the multiplexer 402, changes the gradation according to the characteristics of the photoreceptor, and outputs it as 6-bit data, and a γ correction circuit. Output from 403 (R)
, ? r: Converts 6-bit gradation data indicating the gradation of $ (G) and blue (B) into gradation data (6 bits) of their respective complementary colors, cyan (C), magenta (M), and yellow (Y). A complementary color generation circuit 405 performs conversion, a masking processing circuit 406 performs predetermined masking processing on each Y, M, and C gradation data output from the complementary color generation circuit 405, and each Y, M, and C gradation after masking processing. Enter data and UCR
A UCR processing/black generation circuit 407 that executes processing and black generation processing, and Y and M output from the UCR processing/black generation circuit 407.

A gradation unit that converts each 6-bit gradation data of C1 and BK into 3-bit gradation data YLMI, CL, and BKI, and outputs it to the laser drive processing section 502 inside the multi-valued color laser printer 500. A synchronization control circuit 4 for synchronizing the adjustment processing 408 and each circuit of the image processing device 400
09.

Although details will be omitted, the γ correction circuit 403 has a configuration in which the gradation can be arbitrarily changed using an operation button on the console 700.

In addition, the gradation processing circuit 408 has L U
Y and M output from the UCR processing/black generation circuit 407 in synchronization with the line synchronization signal and pixel clock.
, C, and BK, the count value of the main scanning counter 408a, and the sub-scanning counter 408a.
08b and the edge section information sent from the edge section information storage memory section 206b of the page memory 206 in synchronization with the line synchronization signal and the pixel clock, 3-bit gradation data YLM], , C1, and B
Convert to KI and output.

In this embodiment, it is assumed that the gradation processing circuit 408 uses a Heyer type 3×3 multilevel dither matrix, not shown in FIG. Therefore, the number of gradations of the multilevel color laser printer 500 is the product of the area gradation of 3 x 3 and the multilevel level of 3 bits (that is, 8 levels), which is 3 x 3 x 8 = 72 (8 rounds of floors). .

Next, the processing of the masking processing circuit 406 and the UCR processing/black generation circuit 407 will be explained.

Generally, the arithmetic expression for the masking process of the masking process circuit 406 is as follows: Y, , M, , C,: data before masking process Yo, M
o, Co: Data after masking processing Also, the calculation formula for UCR processing of the UCR processing/black generation circuit 407 is also generally used. Therefore, in this embodiment, the product of both coefficients is used from these formulas to find new coefficients. There is.

In this embodiment, a new coefficient (such as "all") that performs this masking processing and UCR processing at the same time is calculated in advance, and
Furthermore, using the new coefficients, the masking processing circuit 40
6 scheduled input values Y, , M, , C0 (6 bits each)
An output value (such as yo'': a value that is the calculation result of the UCR processing/black generation circuit 407) corresponding to is obtained and stored in a predetermined memory in advance.

Therefore, in this embodiment, the masking processing circuit 406 and U
The CR processing/black generation circuit 407 is composed of a set of ROMs, and the data at the address specified by the inputs Y, M, and C of the masking processing circuit 406 is given as the output of the tJcR processing/black generation circuit 407.

In addition, for fishing on a boat, the masking processing circuit 406 performs Y,
It corrects M and C signals, and performs UCR processing and
The black generation circuit 407 performs correction for color balance in overlapping toners of each color. After passing through the UCR processing/black generation circuit 407, black component data BK is generated by combining the input three color data of Y, M, and C, and the output data of each color component of Y, M, and C is black. The value is corrected by subtracting the component data BK.

In the above configuration, the T correction circuit 403 executes processing based on the γ correction conversion graph shown in FIG. Suppose that processing is executed based on the generation conversion graph, and then the masking processing circuit 406 and the UCR processing/black generation circuit 407 execute processing based on the following equation.
Figure 8(a).

The RGB image data shown in (b) and (C) is T
Correction circuit 403. Complementary color generation circuit 405. Masking processing circuit 406. Then, it passes through the OCR processing/black generation circuit 407 and is converted as shown in FIGS. 12(a), (b), (C), and (d).

Furthermore, if the gradation processing circuit 408 uses a Bayer type 3×3 multilevel dither matrix shown in FIG.
Y in Figure 12 (a), (b), (c), (d),
The MCBK data is shown in Figure 14 (a) and (b), respectively.
), fc) is converted into the data shown in (d).

■Configuration of multivalued color laser printer First, the 15th
The schematic configuration of the multivalued color laser printer 500 will be described with reference to the control block diagram shown in the figure.

A photoreceptor development processing unit 501 uniformly charges the surface of a photoreceptor drum (described later), exposes the charged surface to a laser beam to form a latent image, develops the latent image with toner, and transfers it to recording paper. The details will be explained later, but the development and development of BK data is
A blank developing/transfer section 501bk that performs transfer, a cyan developing/transfer section 501c that develops and transfers C data, and a magenta developing/transfer section 5 that develops and transfers M data.
01m and a yellow developer that develops and transfers Y data.
The transfer unit 501y is provided with a transfer unit 501y.

The laser drive processing unit 502 includes the image processing device 4 described above.
The 3-bit data of Y, M, C, and BK output from 00 (here, image density data) and the page memory 2
A buffer memory that inputs characteristic information C from the characteristic information storage memory section 206b of 06, selects a printing method, and outputs a laser beam, and inputs 3-bit data of Y, M, and C and characteristic information C. 503y, 503m50
3c, and laser diodes 504y and 504 that output laser beams corresponding to Y, M, C, and BK, respectively.
m, 504c, 504bk and laser diode 50
Drivers 505y, 505m, 505c, and 505b drive 4y, 504m, 504C, and 504bk, respectively.
It consists of k.

In addition, the black development transfer section 50 of the photoreceptor development processing section 501
1bk, the laser drive processing section 502, the laser diode 504bk, and the driver 505bk are called a black recording unit BKU (see FIG. 16).

Similarly, the combination U of the cyan developing/transfer section 501c, laser diode 1ζ 504c, driver 505c, and buffer memory 503c is connected to the cyan recording unit CU (see FIG. 16) and the magenta developing/transfer section 501m.
, laser diode 504m, driver 50
5m and buffer memory 503m, magenta recording unit iMU (see Figure 16), yellow developing
Transfer section 501y, laser diode 504y,
Driver 505 M, and.

The combination of buffer memories 503y is called a yellow recording unit I-YU (see FIG. 16). As shown in the figure, each of these recording units is connected to a conveyor belt 50 that conveys the recording paper.
A black recording unit BKU, a cyan recording unit CU, a magenta recording unit MU, and a yellow recording unit YU are arranged around the recording paper 6 in this order from the conveying direction of the recording paper.

Due to this arrangement of each recording unit, the laser diode 5 for black exposure starts exposure first.
04bk, and the laser diode 504y for yellow exposure starts exposure last. Therefore,
There is a time difference in the order of exposure start between each laser diode,
Data recorded during the time difference (output of the image processing device 400)
In order to hold the data, the laser drive processing unit 502 includes the three sets of buffer memories 503y, 503m, and 503c described above.
is provided.

Next, the configuration of the multivalued color laser printer 500 will be specifically explained with reference to FIG.

The multi-value color 1-noser printer 500 includes a conveyor belt I□ 506 that generally feeds the recording paper once, and each recording unit YU arranged around the conveyor belt 506 as described above.
, MU, CU, BKU, and paper feed power cellars l-507a, 507b, which house recording paper. :, Paper feeding power 7h507a
, 507b, the paper feed roller 50 does not feed the recording paper from each of them.
8a, 508b, the register 1 to roller 509 that aligns the recording paper sent out from the paper feed force rollers h507a, 507b, and the conveyor belt 506 to sequentially convey the recording units +3 KU, CU, MU, YU and transfer them. a fixing roller 510 that fixes the printed image on the recording paper, and a paper discharge roller 5 that discharges the recording paper to a predetermined discharge section (not shown).
11. Here, each recording unit 1-YU
, MU, CU, BKU are photosensitive drums 512y, 51
2m, 5], 2c, and 512bk, and chargers 513y, 513m, 513c, and 513b that uniformly charge the photoreceptor drums 512y, 512m, 512c, and 512bk, respectively.
k, photosensitive drums 512y, 51.2m, 512c
Polygon mirrors 514y, 514m, 514c, 514bk and morphs 51.5y, 515m, 515c, 515bk for guiding the laser beam to 512bk,
Photosensitive drum 512y, 5], 2m, 512c, 512
toner developing devices 516y, 516 that develop the electrostatic latent images formed on bk using toners of corresponding colors;
m, 516c, 516bk, and transfer chargers 517y, 517m, 517c that transfer the developed toner image to recording paper.
, 517bk, and photosensitive drum 5 after transfer], 2y, 5
12m, 512c, 5], cleaning device for removing toner remaining on 2bk W518y, 518m.

It consists of 518c and 518bk. In addition, 51.9
y 519m, 519c, 519bk, photoreceptor drums 512y, 512m, 512c, 512bk, respectively
CC for reading the predetermined pattern provided on J2
A D-line sensor is shown, and although its details are omitted, it detects the process status of the multivalued color laser printer 500.

In the above configuration, the operations of the yellow recording units 1 to YU will be explained using exposure, development, and transfer as examples.

Figure 17 (a) and (b) are yellow recording Unisol l-Y
The configuration of the exposure system of U is shown. In the same figure, a laser beam emitted from a laser diode 504y is reflected by a polygon mirror 514y, and then passes through an r-θ lens 520.
y, is further reflected by a mirror 521y522y, and is irradiated onto a photoreceptor drum 512y through a dustproof glass 523y. At this time, since the polygon mirror 514y is rotated at a constant speed by the motor 515y, the laser beam is
It moves in the direction along the axis of the photosensitive drum 512y (main scanning direction). Furthermore, in this embodiment, a photosensor 524y is provided to detect the base point for tracking the scanning position of the main scan, so that the laser beam at the non-exposed position is detected. Since the laser diode 1'' 504y is activated to emit light based on the recorded data (3-bit data from the image processing device 400), multivalue exposure corresponding to the recorded data is applied to the surface of the photoreceptor drum 504y. Performed. Photoreceptor drive J, 5
The surface of 04y is uniformly charged in advance by the charger 513y as described above, and an electrostatic latent image corresponding to the original image is formed by the exposure. The electrostatic latent image is developed by a yellow developing device 516y to become a yellow toner image. This toner image is stored in the cassette 507 as shown in FIG.
a (or 507b) by the paper feed roller 508a (or 508b), and the registration roller 509
In synchronization with the toner image formation in the black recording unit BKU, the toner image is transferred onto the recording paper conveyed by the conveyor heel 1-506.

Other recording units BKtJ, CU, and MU have similar configurations and perform similar operations, but black recording unit l-B
The K U is equipped with a black toner developing device 516bk to form and transfer a black toner image, and the cyan recording unit CU is equipped with a cyan toner developing device 516C to form and transfer a cyan toner image. -MU is equipped with a magenta toner developing device 516m, and forms and transfers a magenta toner image.

■ Multi-value drive drivers 505y, 505m, 505c, 505bk, YM, C, BK sent from the image processing device 400
The corresponding laser diodes 504y, 504m, 504c, and 504 are
This is to perform control for multi-value driving of bk using the optimal printing method. Specifically, when the feature information C is "1",
The corresponding edge pixels are output to the photoreceptor drums 512y, 512m, 512c512bk using the pulse 11 modulation method, and when the characteristic information C is "O", the corresponding edge pixels are output using the power modulation method.

Hereinafter, the multi-value drive driver applied in this embodiment will be described as the 18th driver.
This will be explained in detail with reference to FIG. 22. In addition, Triba 505y, 505m, 505c505bk and,
Laser diode 504y.

504m 504c, 504. bk are the same.
Therefore, here, the driver 505y3'? and the laser diode 504y will be explained as an example.

As shown in FIG. 18(a), the driver 505y turns the laser diode 504y on and off based on a predetermined LD drive clock.
n10ff circuit 550 and 3-bit image density data (
Here, the D/A converts Y data) into an analog signal.
a converter 551; a constant current circuit 552 that inputs an analog signal based on the image density value from the D/A converter 551 and supplies a current Id for driving the laser diode 504y (LD drive current) to the laser diode on10ff circuit 550; Based on image density data, LD
A pulse modulation circuit 553 that modulates the pulse width of the drive clock; a selector 554 that selects the output Vd from the D/A converter 55 or a predetermined value Vd based on the characteristic information C; It is composed of a selector 555 that selects the LD drive clock (2) after pulse modulation and the LD drive clock not subjected to pulse modulation.

Here, the LD drive clock is “ON at 1” o
" is defined as off, and as shown in FIG. 18(b), the laser diode on10ff circuit 550 turns off the laser diode 504y accordingly.

Furthermore, since there is a proportional relationship between the LD drive current 1d and the laser beam power, by generating the I and D drive currents 1d based on the image density data value during power modulation, the laser beam power corresponding to the image density data value can be adjusted. You will get the output. For example, as shown in FIG. 18(b),
When the image density data value is "4'", the constant current circuit 5
A corresponding LD drive current 1d is supplied by 52,
The laser beam power of the laser diode 504y is level 4. Further, when the image density data value is "7", the corresponding I7D drive current 1d is supplied by the constant current circuit 552, and the laser beam power of the laser diode 504y becomes level 7.

Next, FIG. 18(C) shows the configuration of the pulse modulation circuit 553. In this circuit, the image density data is Do,
DI, D2. Input the 4-bit data of D3 and set it to 0 (of
Five levels of values including f) are selected by the D latch 553a. Furthermore, D.

(Same as LD drive clock) represents on/off of the laser beam; when it is 0, the laser beam is off, and when it is 1, it is on.

Furthermore, only when the laser beam is on, one of seven pulses is selected using the 3 bits (image density data) of DLD2 and D3. Below, seven types of adjustments during the pulse will be explained.

First, the LD drive clock is connected to the delay element 553b,
553c and 553d to generate three types of signals, CI, C2°C3. Next, LD drive clock and C
The AI signal is obtained by the NAND 553e of 1, and by passing this and the LD drive clock to the AND 553h, a Pl of about 177 duty is obtained. In the same way, AND from the D drive crosshair and C2, C3 signals.
553f, 553g, and 553i, 553j with a duty of about 277 and about 377. Get P3.

Furthermore, a signal P5 of approximately 13/14 duty is obtained by OR553k of the 2D drive clock and C1. In the same way, from the I, D drive clock and C2, C3 signals, 5
Approximately 9/14 via 53ff, 553m. Approximately 11/14
Duty signal P6. Get P7. On the other hand, the L L drive clock itself becomes Pn with a duty of about 50%. PI, P2. P3. Pn, P5. P6. P7 is input to the data selector 553n, and is image density data DI.

D2. One of them is selected based on D3.

Then, by using A and ND553o, Pn (n is 1 to 7) only when I)0 is on is the LD after 8 cycles of the medium pulse.
Output as drive clock ■.

The laser beam from the laser diode 504y is
Based on the level (corresponding to the gradation value), a latent image as shown in FIG. 18(d) is formed on the photosensitive drum 512y.

Next, referring to FIG. 19(a), the laser diode o
n10ff circuit 550. A specific circuit configuration of the D/A converter 551 and the constant current circuit 552 is shown. Note that, in order to simplify the explanation, the selector 554 and the like will not be described here.

The laser diode on10ff circuit 550 is TTL
Inverters 553 and 554, differential switching circuits 555 and 556 that perform onloff toggle operation, and V
When GI>VO2, the differential switching circuit 555
n, differential switching circuit 556 is off, VGI<
When VO2, the differential switching circuit 555 is off,
Resistors R, , R forming a voltage dividing circuit that generates VO2 that satisfies the conditions for the differential switching circuit 556 to be turned on.
It consists of 3. Therefore, when the LD drive clock is "°1", the output of the inverter 554 generates VGI, the above condition (VGI>VO2) is satisfied, the differential switching circuit 555 is on, and the differential switching circuit 556 is on. of fl, and laser diode t' 50
4 Turn on y. Conversely, when the LD drive clock is O"", there is no output from the inverter 554, so
The differential switching circuit 555 satisfies the above condition (VO2, 2 1 < VO2).
is off, the differential switching circuit 556 is on,
Turn off the laser diode 504y.

The D/A converter 551 includes a latch 557 that latches the input image density data while the LD drive clock is "1", and a V rof that provides the maximum output value V rGf.
Generator 558, image density data and maximum output value V r
It is composed of a 3-bit D/A converter 559 that outputs analog data Vd based on cf. Here, Vd, image density data, and maximum output value V r e f
The relationship with is expressed by the following equation.

The constant current circuit 552 includes the laser diode 50 in the laser diode ON10ff circuit 550 as described above.
4y of current, and the transistor 56
0, and resistors R4 and R1. The output Vd from D/A converter 551 is applied to the base of transistor 560 to determine the voltage applied to resistor R4. In other words, since the current flowing through the resistor R4 is approximately equal to the collector current of the transistor 560, the current Id flowing through the laser diode 504y is controlled by Vd.

FIG. 19(b) shows the output of the latch 557 mentioned above.

Timing charts 1 to 1 show the relationship between VGI, Vd, and Id. Here, Vd is Vrer based on image density data (3 bit data: 8 gradation data from 0 to 7).
X takes values in eight stages from O/7 to 7/7, and Id indicates eight levels from 16 to D based on the value of Vd. The laser diode 504y selects the 19th level on the photosensitive drum 512y according to the 8 levels of this Id (No. - Level 011 - Levelt..., I7 - Level 7).
A latent image as shown in Figure (C) is formed.

In the image forming system to which the vector image printing device of the present invention is applied, the configuration and operation described above are implemented as shown in FIG.
), the 20th pentagon ABCDE is finally
A toner image shown in the figure is formed on recording paper 1. As is clear from the illustration, anti-aliased pixels can be printed more accurately.

In the embodiment described above, the plain memory section 206a and the feature information storage memory section 206b for storing the feature information C were provided separately in the page memory 206, but the present invention is not particularly limited to this.

For example, it is also possible to allocate the -L-order 1 bit of the brain memory section 206a as a feature information storage memory section. In this case, image density near pi 1-1 feature information: 1 bit x 3. Therefore, the γ correction circuit 403 in the image processing device 400 may perform processing as shown in FIG. 21.

〔Effect of the invention〕

As explained above, the screen printing device of the present invention can be used for DTP (Desk 1-Tub Publishing).
The vector image created by the above process is developed into an image deck while being subjected to anti-aliasing processing, and after the specified image processing is performed, the vector image printing device prints it on a multilevel printer. The image data storage means for storing the image data, the feature information storage means for storing the feature information of the image data, the image data stored in the image data storage means, and the feature information stored in the feature information storage means are synchronized. and a printing method selection means for selecting the printing method of the multilevel printer so that the corresponding image data is printed in an optimal state based on the characteristic information, so that the effect of anti-aliasing processing is not impaired. The impression of a vector image can be accurately reproduced.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a schematic configuration of a vector image printing apparatus according to the present invention, FIG. 2 is an explanatory diagram showing a configuration of an image forming system according to the present embodiment, and FIG. An explanatory diagram showing the configuration of the controller, FIG. 3(b) is an explanatory diagram showing the page memory, FIG. 4(a) is a flowchart showing the operation of the PDL controller, and FIG. 4(b) shows bus filling processing. Explanatory diagram, the 4th UA (C) does not show anti-aliasing processing, and the 5th UA
Figures (a) and (b) are explanatory diagrams showing linear solid line division of a figure, Figure 6 is an explanatory diagram showing the approximate area ratio after anti-aliasing processing, and Figure 7 is a feature information storage memory. Explanatory diagram showing characteristic information stored in the section, FIG. 8(a)
, (t)) (C) is an explanatory diagram showing RGB image data stored in the brain memory section of the page memory, FIG. 9 is an explanatory diagram showing the configuration of the image processing device, and FIG.
The figure is an explanatory diagram showing a conversion graph for γ correction of the γ correction circuit, and FIGS. 11(a), 11(b), and 11(C) are complementary color schemes. An explanatory diagram showing a conversion graph for complementary color generation used in the generation circuit,
Figure 12 (a), (b), (C), (d) is the 8th
13 is an explanatory diagram showing the state in which the RGB image data shown in (a), (b) and (C) is output from the UCR processing/black generation circuit. Explanatory diagram showing 71-Rix, Fig. 14(a), (
b), (C), (d) are shown in Figure 12 (a), (b)
, (C), explanatory diagram showing the state in which the Y, M, C, BK data of (d) is converted by the gradation processing circuit, No. 15
The figure is a control block diagram showing a multivalued color laser printer, Fig. 16 is an explanatory diagram showing the configuration of a multivalued color laser blink, and Figs. 17(a) and (t)) are exposure of the yellow recording unit. An explanatory diagram showing the configuration of the system, FIG. 18(a) is an explanatory diagram showing the configuration of a multi-value drive driver,
Figures 8(b), (C), and (d) are explanatory diagrams showing multi-value drive by pulse [11 modulation; Figures 19(a) and (b)
, (C) is an explanatory diagram showing multi-value drive by power modulation,
FIG. 20 is an explanatory diagram showing the final toner image of the pentagon ABCDE shown in FIG. 5(a), FIG. 21 is an explanatory diagram showing the processing of the γ correction circuit in another embodiment, and FIG. )
, (b) are explanatory diagrams showing conventional anti-aliasing processing, Figures 23 (a) and (b) are explanatory diagrams showing anti-aliasing processing using the uniform averaging method, and Figure 24 (a)
), (b) is an explanatory diagram showing anti-aliasing processing using the weighted averaging method, and Fig. 25 (a), (b),
(C) and (d) are explanatory diagrams showing examples of filters used in the weighted averaging method, Fig. 26 is an explanatory diagram showing a convolution method with 3 x 3 pixel reference, and Fig. 27 is a conventional vector image FIG. 4 is an explanatory diagram showing four problems of the power modulation method and the pulse modulation method in the printing device. Explanation of symbols 1, 00 --- Bost communication 200--- PDL controller 201 --- Receiving device 202 --- CP U2O5 --- Internal system bus 204 --- RAM, 205 ---, R0M20
6---One page memory transmitting device 208-------1 /○ device Image reading device Image processing device Multivalued color laser printer

Claims (1)

[Claims] A vector image created by DTP (desk top publishing) or the like is developed into image data while being subjected to anti-aliasing processing, and after predetermined image processing is performed, it is printed using a multilevel printer. In the vector image printing device, an image data storage means for storing the image data subjected to the anti-aliasing process;
a feature information storage means for storing feature information of the image data; and inputting the image data stored in the image data storage means and the feature information stored in the feature information storage means in synchronization; 1. A vector image printing device comprising: printing method selection means for selecting a printing method of a multilevel printer based on characteristic information so that corresponding image data is printed in an optimal state.