JPH049974A - Image forming device - Google Patents

Abstract

PURPOSE:To output a color resolving plate at the spot of an output line where the number of bits is the largest and to prevent the information of Y, M and C data from being lost by forming an image by using the image forming medium of a single color which is excellent in resolution out of plural color image forming signals. CONSTITUTION:An image processing part 102 performs the various correction to the image information of R, G and B from a scanner 101 to convert into the information signals of Y, M, C and Bk. A gradation processing part 204 in the processing part 102 outputs the color resolving plate for the C data which secures three bits. In the case that the color resolving plate is off, the output of a C gradation conversion circuit 301C is outputted to a data line C and Y, M and Bk data is outputted in a state where three and one bit of information are respectively held. In the case that the plate is on, the output of a multiplexer 302 is outputted to the line C and one color is selected according to an output color specifying signal. However, the line C is three bits, the other data need not be compressed and the information is prevented from being lost.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image creating apparatus for creating a negative or bond film for creating printing plates for offset printing, for example.

[Conventional technology]

BACKGROUND ART Prepress printing technology has greatly advanced with the development of electronics, and electronic prepress has become mainstream today.

This electronic plate-making process photoelectrically converts the a-light of the original image, performs predetermined processing on the electrical signal to change the intensity of the light, exposes the photosensitive material (film), and develops it. , the production process is very complicated, and the equipment itself is also large, which results in the printing process being very complicated. The production of negative or positive film as the basis for the original plate had to be extremely expensive.

Conventionally, a document is optically scanned and read as multiple types of color signals, and each color signal obtained thereby is converted into a multiple color image forming signal. An image forming apparatus (Japanese Unexamined Patent Publication No. 85648/1983) has been proposed in which an image is formed using a laser printer using a single color toner in response to one of the image forming signals.

By using this technique, it is possible to shorten the printing time of a film for producing a printing original plate, and to produce the film at low cost.

[Problem to be solved by the invention]

However, in the above-mentioned conventional image forming apparatus, the full-color offset printing original plate is usually three R, G, and B plates of an additive color mixture system, or Y, M, and C plates of a subtractive color mixture system.
, 4 BK plates are output as ink boards (BK plates), so
If the number of gradations of each color is different and the number of gradations of other color data is greater than the number of gradations of Bx data, there is a problem that information will be lost if the separated version is output as a BK version. There is. For example, BK data has many text manuscripts, and 2
Since we are dealing with value data, we prepare only 1 focus, and for other color data, we prepare 2 focus, or more, since many photo manuscripts are used.
- If a number is prepared and B is output as a decomposed version, there is a problem that the information of Y, M, and C data will be lost.

In more detail, the above problem will be explained using FIG. 5 showing the conventional gradation processing section 500 and FIGS. 6 (a), (b), and (C) showing the operation.

FIG. 5 shows a gradation processing section 500 that is provided in an image processing section (not shown) and executes gradation conversion on an image.
A Y gradation conversion circuit 501Y that inputs the Y data signal output from a correction section (not shown), an M gradation conversion circuit 501 that inputs the M data signal, and a C gradation conversion circuit that inputs the C data signal. It is composed of a circuit 501C, a B8 gradation conversion circuit 5018 that manually inputs a BK data signal, and a multiplexer 502 that inputs each of the above data signals and performs data selection processing. Also, as shown in the figure, each of the Y, M, and C data lines has 3 bits, and the BK data line has 1 bit.
It's bit.

In the case of the color separation version OFF signal, the output to the BK gradation conversion circuit 5018 is output as is to the Bx data line, and the Y, M, and C data are also output while holding 3 bits of information each. .

On the other hand, in the case of the color separation ON signal, the BK data line becomes the output of the multiplexer 502, and one color is selected from Y, M, C, and B according to the table below according to the output color designation signal. Since the BK data line is 1 bit, the Y, M, and C data must also be compressed to 1 bit in order to match the BX data line.

A compression circuit (not shown) for compressing this data is provided in each gradation conversion circuit 501.
It is configured to be switched by an FF signal.

In the above configuration (FIG. 5), a state in which information is lost when 3-focus information is changed to 1-bit information will be explained using FIG. 6.

As shown in Figure 6(a), 6-bit information is 64 pixels per pixel.
Can represent gradations. When this is compressed into 3-bit information as shown in Figure 6(b), one pixel can only represent 8 gradations, so this is expressed by the number of pixels (
area gradation conversion). Furthermore, as shown in Figure 6(C), when data that would normally be 3 bits is compressed to 1 bit, 1 pixel of 3 bits corresponds to 8 pixels of 1 bit, and the information becomes 1 bit.
It becomes /8.

The present invention has been made in view of the above, and outputs color separation plates to the part of the output line with the largest number of bits to produce Y, M, and M colors.
, the purpose is to prevent information loss of C data.

[Means to solve the problem]

In order to achieve the above object, the present invention optically scans a document,
A scanning means for reading the contents of a document as a plurality of types of color signals, a color conversion means for converting each color signal read by the scanning means into image forming signals of a plurality of colors, and a plurality of color images converted by the color conversion means. The present invention provides an image forming apparatus including a printing means for forming a C two-side image on an image forming medium using a single color image forming medium having excellent resolution among forming signals.

Further, the image forming medium is a single color toner, and the printing means performs image formation according to one image forming signal among the plural color image forming signals converted by the color converting means. A forming device is provided.

[Function] The image forming apparatus of the present invention converts each color signal obtained by the color conversion means into a single color image forming medium with excellent resolution, that is, the first bit number of the output line, among the plural color image forming signals. Image formation is performed on the image forming medium by outputting color separation plates in areas with a large amount of color.

〔Example〕

Hereinafter, the image forming apparatus of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the overall configuration of an image forming apparatus according to the present invention, in which image information or reflectance information of RlG and B is taken from a color original, and 7" (R
) a scanner 101 that outputs an information signal, a green (G) information signal, and a blue (B) information signal;
inputs each image information signal from , executes various correction processes, and converts it into a yellow (Y) information signal, magenta (M) information signal, cyan (C) information signal, black (BK) information signal, or density information signal. an image processing unit 102 that converts and outputs the image;
A memory 103 for storing image information signals from the image processing section 102 is input, and the image information signals from the image processing section 102, or each image information signal stored in the memory 103 are inputted, and the image information signals from the image processing section 102 are input. Printer 1.04 that prints a predetermined image on recording paper based on an image information signal
It is composed of.

FIG. 2 is a block diagram showing the configuration of the image processing unit 102 shown in FIG. a color correction unit 201 that converts a green (G) information signal and a blue (B) information signal into a yellow (Y) information signal, a magenta (M) information signal, and a cyan (C) information signal; Information belief υ
7. Generate a blank (BX) information signal (black version) from the magenta (M) information signal and the cyan (C) information signal. )
A UCR section 202, a yellow (Y) information signal, a magenta (M) information signal output from the UCR section 202,
A T correction unit 203 adjusts the gamma of the cyan (C) information signal and black (BK) information signal, and gradation processing (image compression such as dither processing) is performed on the image information gamma corrected by the γ correction unit 203. and a gradation processing unit 204 that executes the following operations.

FIG. 3 is a block diagram showing the configuration of the gradation processing section 204. The basic configuration is the same as that explained using FIG. , color separation plates may be output for Y and M data for which 3 focal points are secured).

The gradation processing section 204 includes a Y gradation conversion circuit 301Y that manually converts the Y data signal output from the γ correction section 203;
~1 gradation conversion circuit 301M inputting the M data signal;
A C gradation conversion circuit 301C that manually converts the C data signal, and B
It is comprised of a Bx gradation conversion circuit 3018 that manually inputs the K data signal, and a multiplexer 302 that inputs each of the above data signals and performs data selection processing. Further, as shown in the figure, each of the Y, M, and C data lines has 3 hits, and the Bx data line has 1 bit.

In the above configuration, in the case of the color separation plate OFF signal,
The output of the above C gradation conversion circuit 301C is output as is to the C data line, and the Y and ~1 data are output with 3 bits of information each held, and the BK data is output with 1 viat information held. Ru.

On the other hand, in the case of the color separation ON signal, the C data line becomes the output of the multiplexer 302, and one color is selected from Y, M, C, and BK according to the output color designation signal.
Since the C data line is 3 bits, there is no need to compress the Y, M, and BK data.

FIG. 4 shows another embodiment of the present invention, in which color separation plates may be output for BK data (in addition, color separation plates may be output for M and C data for which 3 hits are secured. However, color separation plates may be output for Y data is 2 bits, so in this embodiment, color separation plates are not output.

The gradation processing unit 204 in this embodiment includes a Y gradation conversion circuit 401Y that inputs the Y data signal output from the T correction unit 203 as in the above embodiment, and an M gradation conversion circuit 401Y that inputs the M data signal. 401M, a C gradation conversion circuit 401C that inputs a C data signal, a BK gradation conversion circuit 401Eh that inputs a B8 data signal, and a multiplexer 402 that inputs each of the above data signals and performs data selection processing. Ru. Further, as shown in the figure, each of the M and C1BK data lines is 3 bits each, and the Y data line is 2 bits.

In the above configuration, in the case of the color separation plate OFF signal,
The output of the above Bx gradation conversion circuit 401BX is BK as it is.
Output to the data line, M and C data are each 3 bits,
The Y data is output with the information of two nodes held.

On the other hand, in the case of the color separation ON signal, the BK delineation becomes the output of the multiplexer 402, and one color is selected from Y, M, C, and BK according to the output color designation signal. In that case, since the BK data line is 3 bits, there is no need to compress each of the Y, M, and C data.

Moreover, based on the present invention, in the embodiment, the color conversion means is
It is configured to form a halftone dot pattern regardless of the type of each color signal obtained by optically scanning a document.

In other words, the laser writing of digital color copying machine is 1.
Since only about 3 bits of information can be stored per pixel, gradation processing (image compression such as dither processing) is performed at the final stage of the image processing unit 102.
Execute. For this reason, we change the processing pattern to create rich gradations for photo originals, sharp edges for text originals, and avoid moiré for printed originals, but for offset printing originals, we change the processing pattern. Regardless of the type of document, most documents are output with a halftone pattern. Therefore, in this embodiment, when outputting as a separated version, a configuration is adopted in which a halftone dot pattern is forcibly selected, ignoring processing pattern switching.

〔Effect of the invention〕

As explained above, according to the image forming apparatus of the present invention, among the plural color image forming signals converted by the color converting means, a single color image forming medium having excellent resolution is used to transfer the image forming signals to the image forming medium. In order to perform image formation on
Information loss of M and C data can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the overall configuration of the image forming apparatus according to the present invention, FIG. 2 is a block diagram showing the configuration of the image processing section shown in FIG. 1, and FIG. 3 is the gradation level shown in FIG. 2. FIG. 4 is a block diagram showing the configuration of the gradation processing section shown in FIG. 2, and FIG. 5 is a block diagram showing the configuration of the conventional gradation processing section. Figure, Figure 6(a)
, (b), and (C) are explanatory diagrams pointing out problems in the conventional gradation processing section. Explanation of symbols 101 Scanner 102 Image processing section 103/Nomori 104 Printer 204 - Gradation processing section 30] Y, 401 Y-Y gradation conversion circuit 301M, 401M ~1 gradation conversion circuit 301C, 4
01C-C gradation conversion circuit 3018K, 401B, -BK gradation conversion circuit 302.
402 multiplexer

Claims (2)

[Claims] (1) a scanning means for optically scanning a document and reading the contents of the document as multiple types of color signals; a color conversion means for converting each color signal read by the scanning means into image forming signals of multiple colors; and the color conversion and printing means for forming an image on the image forming medium using a single color image forming medium having excellent resolution among the plural color image forming signals converted by the means. Image forming device. (2) In claim 1, the image forming medium is a single color toner, and the printing means responds to one image forming signal among the plurality of color image forming signals converted by the color converting means. An image forming apparatus characterized in that an image forming apparatus executes image formation.