JPH0452157A - Image formation device - Google Patents

Abstract

PURPOSE:To control superimposition of images by a method wherein presence of each of output color elements is judged with a first image composed of a plurality of output color elements, each of the output color elements is synthesized with priority given either to the first or a second image, and formation of the image is made according to the result of the synthesization. CONSTITUTION:Image signals 13-1-4 for each of color elements are read out of image memories 7-1-4 according to a vertical synchronizing signal VSYNC and a horizontal synchronizing signal HSYNC and after selection is made with a color selector, a signal Vout114 for a first output color element is sent out. At the same time, a signal VI21 indicating presence of an image is sent from a circuit that generates said signal. Then switchover is made, according to the signal 21 indicating the presence of the image, between a signal Vout229 for a second output color element read out with a color scanner 23 and the signal Vout114, and a synthesized image signal Vout328 is sent out. Switchover is made, according to the signal VI indicating the presence of the image, between the signal Vout1 and the signal Vout2. Therefore clear solid images can be obtained because scanner-read images are eliminated from a marginal part P1 as well as a black part P2 and a red part P3 of PDL images.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming apparatus, and particularly to an image forming apparatus that forms an image by combining a binary image and a multivalued image.

[Prior art] Conventionally, color PDL (Pag) is transmitted from a host computer, etc.
The printer that receives (Description Language) data and forms a color image includes a controller section 37 and a color printer 11, as shown in FIG.
It is made up of.

As shown in the figure, the color PDL data sent from the host computer 18 via the interface 17 and the external interface 5 is stored in the PDL data memory 6.
After being stored in , the CPU 1 develops the data into color image data, and writes the data into the image memories 7-1 to 7-4, respectively.

On the other hand, the color printer 11 has a plurality of output color components (C:
Cyan, M: Magenta, Y:
This is a color printer that performs image formation in a field-sequential manner for (yellow, k: black), and is configured such that each output color component C, M, Y, and K corresponds to each image memory 7-1 to 7-4. The address generator 9 generates read addresses from each of the image memories 7-1 to 7-4 based on the synchronization signal 16-1 from the color printer 11.

In addition, in the color printer 11, depending on which output color component is being formed, the read target memory is
Only one output color component data selected by No. 1 and read from one image memory is sent to the color printer 11 to form an image. This is then repeated for the four color components to obtain a color image.

Generally, color PDL data is color characters.

Since the main target is figures, illustrations, etc., 300
Although a high-definition image memory with a dpi to 400 dpi is required, gradation is not so necessary, so each image memory 7-1 to 7-4 is configured with two values (1 bit) for each output color component. Often.

[Problem to be solved by the invention] However, in the above conventional example, color characters are used.

Although it is suitable for printing binary images of each color such as figures and illustrations, a color copying machine is used instead of the color printer 11, and the image read by the scanner section of the color copying machine and the controller section 18 are Color P generated
When trying to print by compositing DL images, there was a drawback that the compositing did not work properly.

That is, as shown in FIG. 3(a), an image 32 read by a scanner and a color PDL image 31 ("1" green: C
+Y, r2J black: and r3J red: M+Y) to obtain a composite image 33, the controller unit 18 sends each color component image sequentially as shown in FIG. 3(b). Therefore, if an attempt is made to switch and synthesize the color PDL image 31 and the scanner-read image 32 based on these signals, for example, while forming a magenta component image, 36-1 will be output as the color PDL image. Therefore, the scanner-read images are output for the portions "1" and "2".

Therefore, the "1" part is not solid green, and the "2"
The parts are not solid black.

Therefore, such pixel-by-pixel synthesis is not possible; instead, a separate area signal generation circuit is provided and the area signal is used for switching and synthesis, or the color PDL image and the scanner-read image are synthesized so that they do not overlap.

The present invention was made to solve the above problems, and
An object of the present invention is to provide an image forming apparatus that can suppress overlapping of images when forming images by combining first and second images having a plurality of output color components.

[Means for Solving the Problems] In order to achieve the above object, an image forming apparatus of the present invention has the following configuration. That is, the image forming apparatus combines first and second images each having a plurality of output color components to form an image of each output color component, and determines the presence or absence of each output color component from the first image. a determining means for combining each output color component with priority given to the first or second image according to the result of the determining means; and an image forming means for forming an image.

Preferably, the first image is binary for each output color component, and the second image is multivalued for each output color component.

Furthermore, preferably, one aspect is that the image formation is performed in a field-sequential manner.

[Operation] In the above configuration, the presence or absence of each output color component is determined from the first image having a plurality of output color components, and depending on the result, priority is given to the first or second image, and each output color component is Synthesize. Then, image formation is performed based on the combined output color components.

[Embodiments] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<First Embodiment> FIG. 1 is a block diagram showing a color copying machine compatible with color PDL in a first embodiment.

As shown in the figure, the color PDL data sent from the host computer 18 via the interface 17 and the external interface 5 is stored in the PDL data memory 6.
After being stored in , the CPU 1 develops the data into color image data, and writes the data into the image memories 7-1 to 7-4, respectively.

On the other hand, the color printer 11 is, for example, a color printer that sequentially forms images for a plurality of output color components (C, M, Y, k), and has an image memory 7 for each output color component.
-1 to 4 correspond.

Further, the address generation section 9 generates read addresses for each of the image memories 7-1 to 7-4 based on the synchronization signal 16-1 from the color printer 11.

Each color component image data 13 read out according to this read address is selected by a color selector 19 depending on which output color component is being formed in the color printer 11, and sent to the full-color scanner/printer 11.

Further, each color component image data 13 is input to an image presence signal generation circuit 20, which generates an image presence signal 21 indicating the presence or absence of an image for each pixel. This image presence signal generation circuit 20 is a circuit that determines whether each input color component signal 13 belongs to a predetermined valid image group or an invalid image group. For example, invalid image group: each output color. Valid image group in which all components are “0”: If other than that, the image presence signal generation circuit 20 is as shown in FIG. 2(b).
It is configured as shown in .

The serial interface 10 is a full color scanner/
This is for serial communication between the printer 11 and the CPUI, and the ROM2. The RAM 3 stores program data, control data, etc. executed by the CPUI. The font ROM 4 also holds font data for developing color characters in PDL data into image data.

FIG. 2(a) is a schematic block diagram showing the internal configuration of the full-color scanner/printer 11. As shown in FIG.

As shown in the figure, the image data 14 of each output color component sent from the controller section 37 is transferred to the binary/multi-value conversion section 24.
The data is converted from binary data to multi-value data 3°, and is input to the selector 25. On the other hand, the color scanner unit 23
The image data 29 of each output color component read by is also input to the selector 25, and the two output color component signals are switched by the above-mentioned image presence signal 21, combined, and sent to the color printer 26.

The synchronization signal 27 sent from the color printer 26 is
It is sent to the controller section 37 via the sequence controller 22, and is also sent to the color scanner unit 23.
It will also be sent to

As shown in FIG. 3(a), the color scanner unit 2
A multilevel scanner read image 32 read in step 3,
When combining the images read out by the controller unit 37 pixel by pixel to obtain a composite image 33, the controller unit 37 uses 36 pixels shown in FIG. 3(b) corresponding to each output color component.
Each output color component image -1 to -4 is read out, and at the same time, a signal obtained by calculating the logical sum of each color component is read out as an image presence signal 21, as shown in 36-5 shown in FIG. 3(b).

FIG. 4(a) is a timing chart during composite printing.

In the figure, the vertical synchronization signal VSYNC and the horizontal synchronization signal HSYNC are part of the synchronization signal 16-1 from the printer 11. Based on these synchronization signals, each color component image signal 13-1 to 4 is read out from each image memory 7-1 to 7-4, and selected by the color selector 19 to become the first output color component signal V, t. , 14 are sent out. At the same time, the image presence signal Vi2 is output from the image presence signal generation circuit 20.
1 is sent.

On the other hand, the second image read by the color scanner unit 23
The output color component signal is ■. ut229 and the above-mentioned V,
, t114 are switched based on the image presence signal 21 and synthesized to form an image signal (■). ut! 28 is sent out.

FIG. 4(b) is a detailed timing chart of section 2 shown in FIG. 4(a).

As shown in the figure, V 0utl and V
0ut2 can be switched. Therefore, in addition to the edge portion P1 in the PDL image, the black portion P2. Since the scanner read image is also removed from the red portion P3, a clear solid image can be obtained.

Next, the processing procedure at the time of composite printing will be explained below according to the flowchart shown in FIG.

First, in step 5IOI, the PDL data is received from the host computer 18 via, for example, the R5-232G interface 17 and the external interface 5, and the
Insert into DL data memory 6.

Next, in step 5102, the data is developed in the image memories 7-1 to 7-4, respectively.

Next, in step 5103, the color selector 19 is
configuring to select component images, followed by step 510
4, the color printer 26 is activated. Then, the color scanner 23 reads the original image in synchronization with the synchronization signal 27.16-1 from the color printer 26, and at the same time reads one composite portion data from the image memory 7. Combine images and form an image for one composite. Then, in step 5105, M, C
A full-color image is formed by determining whether image forming processing has been performed for each color component of , Y, and repeating the above-described processing for all color components.

Second Embodiment Next, a second embodiment according to the present invention will be described below with reference to FIGS. 7 and 8.

FIG. 7 is a schematic block diagram showing the configuration of an image forming apparatus in a second embodiment.

The difference from the first embodiment shown in FIG. 1 described above is that an image presence signal memory 7-5 is provided in place of the image presence signal generation circuit 20, and the readout signal from the memory 7-5 is used as an image presence signal. This point was set at 21. The image presence signal memory 7-5 contains the result of determining whether each pixel belongs to a valid pixel group or an invalid image group when the CPU 1 develops PDL data and writes it to the image memories 7-1 to 7-4. Write. This embodiment requires one extra memory brain compared to the first embodiment, but on the other hand,
It has the advantage that halftones can be expressed using a dither method or the like for each color component image memory.

However, when using the dither method, the halftones can be set to rOJ and “1”.
'', therefore, if used in the first embodiment, the scanner image will be synthesized for the rOJ portion.

Therefore, in the second embodiment, even for the part that becomes "0" by the dither method, for the part that has an image on the PDL data before expansion, the image presence signal memory 7-5 is stored as "0".
By writing "1" (with image), the dither method can be used.

FIG. 8 is a block diagram of the full color memory/printer 11 of the second embodiment. The difference from the first embodiment is that
Instead of the color scanner unit 23, the readout image 42 from the full color image memory 38 and the PDL image 3
This is the point where 0 is synthesized.

The full color image memory 38 has R (Red) G (Gr
It is composed of three color components, een) and B (Blue), and requires a lower resolution than an image memory, but each color component has multiple values (for example, 8 bits). The RGB image read from the full-color image memory is converted by the RGB/CMYk conversion circuit 39 into output color component data corresponding to each color component formed by the color printer 26.

As described above, according to the above-described embodiment, when combining an image from an external host computer and an image read by a scanner, the host computer image is converted into a scanner by extracting an image presence signal from the computer image. It can be inserted into the scanned image. In particular, in the embodiment, when image formation is performed in a frame-sequential manner, it is possible to reliably erase the natural image portion of the portion where the computer images are combined, so that a composite image with good image quality can be obtained.

Note that a color laser beam printer, a color tod printer, a color inkjet printer, or the like can be used as the printer.

Further, the computer image is not limited to binary data, and may be multi-value data.

[Effects of the Invention] As explained above, according to the present invention, it is possible to suppress the overlap of images when forming an image by combining the first and second images each having a plurality of output color components. can.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram showing the configuration of a color image forming apparatus in the first embodiment, FIG. 2(a) is a detailed block diagram showing the configuration of a color scanner/printer, and FIG. 2(b) is an image FIG. 3(a) is a diagram showing the configuration of the signal generation circuit. FIG. 3(a) is a diagram explaining image synthesis. FIG. 3(b) is a diagram showing images of each color component outputted in sequence. FIG. , (b) is a timing chart of image composition, FIG. 5 is a flowchart showing image composition, FIG. 6 is a schematic block diagram showing the configuration of a general color image forming apparatus, and FIG. 7 is a diagram of the second embodiment. FIG. 8 is a schematic block diagram showing the configuration of a color image forming apparatus. FIG. 8 is a detailed block diagram showing the configuration of a full color memory/printer. In the figure, 1...CPU, 2...ROM, 3...RA
M. 4... Font ROM, 5... External interface, 6... PDL data memory, 7-1 to 7-4...
Image memory, 9...Address generator, 10...Serial interface, 11...Full color scanner/
Printer, 18...Host computer, 19...
Color selector 20... Image presence signal generation circuit. Patent applicant Canon Co., Ltd. agent Patent attorney Yasunori Otsuka (and 1 other person) Figure 4 (b)

Claims (3)

[Claims] (1) An image forming apparatus that composes first and second images each having a plurality of output color components and forms an image of each output color component, which determines the presence or absence of each output color component from the first image. a determining means for determining, a combining means for combining each output color component with priority given to the first or second image according to the result of the determining means, and a combining means for combining each output color component combined by the combining means An image forming apparatus comprising an image forming means for forming an image based on the image forming means. (2) The image according to claim 1, wherein the first image is binary for each output color component, and the second image is multivalued for each output color component. Forming device. (3) The image forming apparatus according to claim 1, wherein the image formation is performed in a frame-sequential manner.