JPH0583540A - Recorder - Google Patents

Abstract

PURPOSE:To provide a color printer preventing the color slurring of the printed results of binary black-and-white images or the reduction of resolution in the case of printing image data prepared by synthesizing color images such as natural picture, etc., and binary black-and-white image data such as characters or line drawings, etc. CONSTITUTION:The corresponding bit of a bit map 12 is turned to '1' when a line drawing extracting circuit 20 extracts the dots constituting a black character/black line drawing from synthetic image data prepared by synthesizing color image data and binary black-and-white image data. A color output control circuit 15 turns the CMY (three primary colors) of chrominance signals top '0' when the bit of the bit map memory 12 is '1' corresponding to the dots of chrominance signals from a color correction circuit, 14, K (black) is transformed to a maximum value and outputted, and a printer engine 16 executes printing only with K ink.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording device, for example, a recording device such as a color printer.

[0002]

2. Description of the Related Art Conventionally, in the field of color printing, in order to improve color reproducibility, printing is performed using K (black) ink in addition to Y (yellow), M (magenta) and C (cyan) primary color inks. The method of doing has been taken. This is originally YMC
If each ink is printed in the same amount, it should become black due to the principle of subtractive color mixing. However, even if three colors are combined, pure black is not obtained, and K ink is used separately.

Further, for other colors, color correction such as masking and UCR (undercolor removal) is performed to improve color reproducibility. Here, a specific printer will be described as an example. A printer capable of expressing 256 gradations in each YMC can express 256 cubes, or approximately 16 million colors. It is expressed that the smaller the YMC value is, the lighter each color is, and the larger the YMC value is, the darker each color is.
For example, the color mixture represented by Y = M = C = 0 is white, and conversely,
The color mixture represented by Y = M = C = FF (hexadecimal number) is black.

Therefore, for example, the color information of black characters in a document is Y = M = C = FF. Y =
When the color information of M = C = FF is passed through the color correction circuit described above, the ink amount of each color is adjusted to express a color closer to black. Of course, in the case of black included in a color image, the color reproducibility is improved by performing color correction to bring it closer to pure black. However, it is desirable that black characters and the like be printed only by K without color correction in order to prevent color shift and deterioration of resolution.

Therefore, in addition to the YMC color information, binary black-and-white bit map information Bi is added. When Bi = 1, the binary black-and-white image is black.
When i = 0, the color image is black.
There was a method of printing at an appropriate ratio of MCK.

[0006]

However, for example, if an existing color image file on a computer is used,
When synthesizing a binary black-and-white image file of an existing document or the like, after the binary black-and-white image data is converted into RGB data or the like so as to fit the color image file, the color image file and the binary black-and-white image file are combined. Are generally combined into a single composite image file.

The composite image file cannot distinguish between black in a color image and black in a binary black-and-white image. Therefore,
When the composite image file is printed by a color printer, 2
A value black-and-white image cannot be printed with only K, and there are problems such as a noticeable color shift and a decrease in resolution in a binary black-and-white image such as a document or a black line drawing.

[0008]

SUMMARY OF THE INVENTION The present invention is intended to solve the above problems, and has the following structure as one means for solving the above problems. That is, first extracting means for extracting binary image data from image data, and second extracting means for extracting binary image data of a specific color from the binary image data extracted by the first extracting means. And a binary image data extracted by the second extracting means is recorded in a single color without color correction, and the other than the binary image data is color-corrected and recorded in a mixed color.

[0009]

With the above arrangement, it is possible to provide a recording apparatus for extracting binary image data from image data and recording the image without color correction. For example, it is possible to provide a recording apparatus that does not cause color misregistration or reduction in resolution in the recording result of a binary image.

[0010]

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

[0011]

[First Embodiment] FIG. 1 is a block diagram showing a configuration example of the first embodiment. Reference numeral 200 is an external device such as a host computer that sends image data, and 100 is a color printer that prints an image from the image data sent from the external device 200.

A bit map memory 12 stores black line drawing data. 13 is a full color memory for storing image data. Reference numeral 14 is a color correction circuit that performs color correction on the image data. A color output control circuit 15 controls color output. 16 is a printer engine. Reference numeral 20 is a line drawing extraction circuit including a line drawing extraction circuit 21 and a black line drawing detection circuit 22. The operation will be described below along with the flow of signals.

The image data sent from the external device 200 is input to the line drawing extraction section 20. Although the details of the operation will be described later, the line drawing extraction section 20 detects dots forming a black character black line drawing from the input image data, stores the black line drawing data (Bi) in the bit map memory 12, and stores the image data. Stored in the full color memory 13. When a dot forming a black character black line drawing is detected, the bit corresponding to the dot in the bit map memory 12 is set to 1
(Bi = 1). The bit corresponding to the dot that does not form the black character black line drawing of the bit map memory 12 is 0.
(Bi = 0).

Next, the image data read out from the full color memory 13 is masked or UCed by the color correction circuit 14.
It becomes a color signal of YMCK that has been subjected to color correction such as R and is sent to the color output control circuit 15. The color output control circuit 15
The black line image data (Bi) is read from the bit of the bit map memory 12 corresponding to the dot of the color signal sent from the color correction circuit 14. The color output control circuit 15 uses Bi =
When it is 0, the input color signal is sent to the printer engine 16 as it is. When Bi = 1, YMC of the input color signal is set to 0 and K is converted to the maximum value, and then the printer engine 16 is converted. send.

Accordingly, the printer engine 16 prints black characters and black line drawings with only K (black) ink, and prints images other than black characters and black line drawings with four inks of YMCK. Next, an operation example of the line drawing extraction unit 20 will be described with reference to FIG. FIG. 2 is a flow chart showing an operation example of the line drawing extraction unit 20. The line drawing extraction unit 20 stores the image data of 8 × 8 dots from the image data sent from the external device 200 (S1). In order to obtain the brightness of each dot, the color information of the 8 × 8 dot image data stored in the memory is
The Y space is converted to the YUV space (S2).

Generally, a character or a line drawing is composed of continuous pixels of the same color. Therefore, a character or a line drawing has the characteristic that the pixel of interest and the surrounding pixels of the pixel of interest have the same color except for the edge of the image, and the luminance of the edge greatly changes. In the present embodiment, the character line drawing is extracted below by utilizing the luminance change of the characteristic. Specifically, the difference in brightness δ1 between the target pixel and the pixel to the left of the target pixel and the difference in brightness δ2 between the target pixel and the pixel immediately above and adjacent to the target pixel are checked (S3). Next, δ1
Alternatively, δ2 is compared with a predetermined value D (S4, S5). δ
When 1 ≧ D or δ2 ≧ D (y), the process proceeds to step S6. When δ1 <D and δ2 <D (n), it is determined to be other than the character line drawing (S12).

In step S6, the luminance L3 of the pixel of interest and the pixel adjacent to the right of the pixel of interest and the luminance L4 of the pixel of interest and the pixel adjacent to the pixel underneath the pixel of interest are checked, and subsequently L3 or L4 and the luminance L0 of the pixel of interest are checked. Are compared (S7, S8). L3 = L
When 0 or L4 = L0 (y), the process proceeds to step S9. When L3 ≠ L0 and L4 ≠ L0 (n), it is determined that the line drawing is not a character line drawing (S12).

The above steps from S1 to S8 are executed by the line drawing extraction circuit 21. Next, at step S9, when the luminance L0 = 0 of the pixel of interest (y) (y), the process proceeds to step S10. When the luminance L0 ≠ 0 of the pixel of interest (n), it is determined to be other than the black character black line drawing (S11). Next, in step S10, it is determined that the character is a black character black line drawing, and the bit corresponding to the pixel of interest in the bit map memory 12 is set to 1.

The above steps S9 and S10 are executed by the black line image detection circuit 22. As described above, according to this embodiment, a black character or a black line drawing is extracted from a composite image file in which a color image and a binary monochrome image sent from an external device are combined, and the black character or the black line drawing is K ( It can be printed with black ink only. Therefore, even if the composite image data is printed by a color printer, it can
Value There is no color misregistration or reduction in resolution in the black and white image print result.

[0020]

[Second Embodiment] A second embodiment of the present invention will be described below. In the second embodiment, the same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. The difference between the second embodiment and the first embodiment is that the first embodiment is a color printer that stores a full-color image as it is in a memory and prints it, whereas the second embodiment compresses the full-color image. It is a color printer that stores in memory, expands and prints.

FIG. 3 is a block diagram showing a configuration example of the second embodiment. In FIG. 3, 31 is a compression circuit for compressing a full-color image, and 32 is a decompression circuit for decompressing the compressed full-color image. The operations of the compression circuit 31 and the decompression circuit 32 are the same as those described in Japanese Patent Application Laid-Open No. 03-096685 "Image Coding Device", and detailed description thereof will be omitted.

Reference numeral 12 is a bit map memory for storing the line drawing data of the black character black line drawing among the line drawings extracted by the line drawing extracting unit 20, and 17 is a line drawing other than the black character black line drawing among the line drawings extracted by the line drawing extracting unit 20. It is a bit map memory + color memory that stores data. Generally, a composite image in which a character line drawing is combined with a full-color image such as a natural image is
There is a sharp edge on the boundary between the full-color image and the character / line drawing, and the compressed and expanded image has a problem that noise is generated around the character / line drawing or the compression ratio is not increased.

Therefore, in the second embodiment, a method of not compressing and expanding a character line drawing for the composite image is used. That is,
Before compressing the composite image, a character line drawing is extracted and separated from the composite image, and the black character black line drawing is stored in the bit map memory 12.
Character line drawings other than black character black line drawings are temporarily stored in the bit map memory + color memory 17, respectively.

In the composite image from which the character line drawing has been extracted and separated, the character line drawing portion is replaced with the surrounding background color, and then the compression circuit 31.
And stores it in the full-color memory 13. The image decompressed by the decompression circuit 32 and the character line drawing other than the black character black line drawing of the bit map memory + color memory 17 are combined by the color correction circuit 14 to form a color signal. The color output control circuit 15
A black character black line image is read from the bit of the bit map memory 12 corresponding to the dot of the color signal sent from the color correction circuit 14. When the black character black line drawing data exists in the bit, the color output control circuit 15 converts YMC of the input color signal into 0 and converts K into the maximum value, and sends them to the printer engine 16.

Therefore, the printer engine 16 prints black characters and black line drawings with only K (black) ink, and prints images other than black characters and black line images with four inks of YMCK. As described above, according to this embodiment, the first
Similar to the embodiment, even when the composite image data in which the color image and the binary black-and-white image are combined is printed by the color printer, the print result of the binary black-and-white image such as a document or a line drawing causes a color shift or a reduction in resolution. Absent. Further, even if the color image is compressed and expanded, noise does not occur around the character line drawing, and the compression rate can be improved.

[0026]

[Third Embodiment] A third embodiment of the present invention will be described below. In the third embodiment, the same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. The difference between the third embodiment and the first embodiment is that the character line drawing to be extracted is one black color in the first embodiment.
6 colors of green, blue, yellow, magenta and cyan (hereinafter abbreviated as business color) and black character line drawing YMC
It is to decompose into K and extract.

FIG. 4 is a block diagram showing a configuration example of the second embodiment. In FIG. 4, a business color / black line drawing detection circuit 23 detects dots forming a character line drawing of either a business color or black from the input image data. For example, when dots forming a yellow character line drawing are detected, yellow line drawing data (BYi = 1)
Is stored in the corresponding bit of the bit map memory (Y) 33, and the image data is stored in the full color memory 13. Further, for example, when the dots forming the character line drawing of green are detected, the green is separated into the three primary colors of YMC, and the yellow line drawing data (BYi = 1) is stored in the corresponding bit of the bit map memory (Y) 33. Then, the cyan line drawing data (BCi = 1) is stored in the corresponding bit of the bit map memory (C) 35, and the image data is stored in the full color memory 13.

That is, in the case of dots of character line images of yellow, magenta, cyan, and black that can be printed in a single color, the line image data is stored in any one of the bit map memories 33 to 36, and the red, which prints in mixed colors, Bitmap memory 33-35 for green and blue dot drawings
The line drawing data is stored in two of them. The bit corresponding to the dot which does not form the character line drawing of the bit map memories 33 to 36 is 0.

Next, the color output control circuit 15 reads the line drawing data from the bits of the bit map memories 33 to 36 corresponding to the dots of the color signals sent from the color correction circuit 14. When all the line drawing data read from the bit map memories 33 to 36 are 0, the color output control circuit 1
Reference numeral 5 denotes the printer engine 1 that directly receives the input color signal.
Send to 6.

For example, when the magenta line drawing data (BMi) read from the bit map memory (M) 34 is 1,
When the line drawing data read from the other bit map memories 33, 35 and 36 is 0, the color output control circuit 15
Converts M of the input color signal to the maximum value, and outputs Y, C,
K is set to 0 and sent to the printer engine 16 to print a character line drawing with only M (magenta) ink. Further, for example, the yellow line drawing data (BY) read from the bit map memory (Y) 33 and the bit map memory (M) 34.
i) and magenta line drawing data (BMi) is 1 and line drawing data read from the other bit map memories 35 and 36 is 0, the color output control circuit 15 outputs Y and M of the input color signals. Is converted to a maximum value, C and K are set to 0, the value is sent to the printer engine 16, and a red character line drawing is printed with Y (yellow) ink and M (magenta) ink.

In other words, yellow, magenta, cyan, and black characters and line drawings are printed with only one ink of YMCK, and red, green, and blue characters and line drawings are Y.
Printing is performed with a mixed color of two inks of MC. As described above, according to the present embodiment, business color or black characters or line drawings are extracted from a composite image file in which a color image and a binary image sent from an external device are combined, and yellow, magenta, Cyan, black letters and line drawings are YMCK
It is possible to print with any one of the inks, and the letters, line drawings of red, green, and blue can be printed with a mixed color of any two inks of YMC. Therefore, even if the composite image file is printed by a color printer, no color shift or deterioration in resolution occurs in the print result of a binary image such as a document or a line drawing. Further, when printing a business color character or line drawing, a normal color printer needs to print four times with four colors of YMCK, but in the present embodiment, one color of YMCK once or two colors. It is possible to improve the printing speed by printing twice.

[0032]

As described above, according to the present invention, it is possible to provide a recording apparatus for extracting binary image data from image data and recording without performing color correction.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration example of an embodiment according to the present invention.

FIG. 2 is a flowchart showing an operation example of a line drawing extraction circuit in this embodiment.

FIG. 3 is a block diagram showing a configuration example of a second embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration example of a third embodiment of the present invention.

[Explanation of symbols]

 12 bit map memory 13 full color memory 14 color correction circuit 15 color output control circuit 16 printer engine 17 bit map memory + color memory 20 line drawing extraction unit 21 line drawing extraction circuit 22 black line drawing detection circuit 23 business color / black line drawing detection circuit 33 to 36 Bitmap memory 100 Color printer 200 External device

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H04N 1/46 9068-5C

Claims (1)

[Claims] 1. A first extracting means for extracting binary image data from image data, and a second extracting means for extracting binary image data of a specific color from the binary image data extracted by the first extracting means. A recording means for recording the binary image data extracted by the second extracting means without color correction and recording the other than the binary image data with color correction. apparatus.