JPH09314912A - Color printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To print relatively simple color data with a few number of colors at a high speed. SOLUTION: A color printer 205 has a constitution wherein RGB data 204 inputted from a higher level computer 201 are converted into CMYK data 211 by means of a CMYK converting function 208 of a printer controller 206 and they are printed on a paper fed from a paper feeding part through a laser 212, a photosensitive body 213, multi-color toners 215 and an intermediate transfer drum 214. On a printer controller 206, a color discriminating means 207 for discriminating the number of colors of coming RGB data, a CMYK converting table 209 for converting data of the RGB data into specified one or two colors (process colors) of the CMYK data 211 and a CMYK forcibly converting function 210 are provided and by reducing the number of motions of bonding of each color toner 215 to the photosensitive body 213, high speed color printing of the RGB data 204 with a few number of colors is realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color printing technique, and in particular, as a result of identifying a color included in original data, it is determined that the color is not black and there is no inconvenience in the color print output result. In this case, the present invention relates to a color printing technique capable of realizing high-speed color printing by forcibly converting the color into a process color (C, M, or Y).

[0002]

2. Description of the Related Art For example, SoftBank Corp., 19
Published on February 20, 1996, "Multimedia Encyclopedia" P21
As described in documents such as 7 to P218, P713, etc., a color display device or the like used in an information processing device such as a computer usually uses an RGB color system, while a color printing device , CMYK color system is used. Therefore, when outputting color data created on a computer with a color printing device,
Data conversion is required.

A color printing control method according to the prior art will be described below with reference to FIGS. 6 and 7. FIG. 6 is a flowchart showing an example of a possible conventional color printing process, and FIG. 7 is a conceptual diagram showing an example of a possible configuration of a conventional computer and a color printing apparatus.

RGB data 704 created by various applications 702 of a computer 701 such as a PC (personal computer) is transmitted to a printer controller 706 in a color printing device 705 via a printer driver 703 (step 61). .
This sending data is RGB data 704 whose color information is shown by RGB representation.

The printer controller 706 identifies the colors used in the RGB data by the color identifying means 707, and uses the CMYK conversion function 708 to identify each identified color as the process color of the color printing apparatus 705.
After conversion into K representation (step 62), bitmap data 709 (709C, 709M, 70) of each process color
9Y, 709K) is generated (step 63).

The laser 710 is driven based on the bit map data 709 of each process color created above (step 64). Here, in order to facilitate understanding, the following processing will be described using the case where the process color is yellow (Y) as an example.

The laser 710 is driven (step 6
4) After forming a yellow latent image on the photoconductor 711 (step 65), the latent image is developed with yellow toner 713Y (step 66). Thereafter, the yellow toner 713Y is placed on the intermediate transfer drum 712 to generate a yellow color image (step 67). The processing (steps 64 to 6)
7) is performed for other process colors (C, M, K) to form a full-color image on the intermediate transfer drum 712 (step 68). Therefore, the photoconductor 711 operates four times in total to form a color image on the intermediate transfer drum 712.

At this time, the processing (steps 64 to 6)
The order of performing 7) does not matter from any process color. Finally, the paper is pulled out from the paper feed unit 714, and the printing process is completed (step 69).

[0009]

When a document is created on the computer 701, it is extremely difficult to express the color by using the process colors of the color printing device 705. For example, “red” used in the document is a color different from magenta (M) which is the process color (CMYK color system) of the color printing device 705. Therefore, when one color “red” is generated by the color printing device 705, two process colors, yellow (Y) and magenta (M), must be used.

In the above-mentioned prior art, even when the application 702 uses only one color or two colors,
When performing printing processing on the color printing apparatus 705 side, it is necessary to use three process colors, and since the photoconductor 711 is operated for each process color, CMYK
There is a technical problem that the printing speed becomes slower as the number of process colors used in the data increases.

In the current business document, a part of the document is
In many cases, only one color other than black is used, and even in the case of such relatively simple color data, in the conventional technique, full-color printing is performed at the time of printing output, not only the printing speed is slowed down, but also color toner and the like are used. Resources such as printing materials are wasted.

An object of the present invention is to provide a color printing technique capable of realizing high-speed color printing by reducing the number of operations of the photoconductor by suppressing the number of process colors used during printing to a necessary minimum. To do.

Another object of the present invention is to provide a color printing technique capable of printing simple color data having a relatively small number of colors at high speed.

Another object of the present invention is to provide a color printing technique capable of saving resources such as color toner.

[0015]

The color printing apparatus of the present invention forcibly processes data other than black (C, M, or Y) when converting received RGB data into CMYK data. ) By converting to CM
The number of process colors used in YK data is suppressed to a necessary minimum, the number of operations of the photoconductor for forming a latent image for each color is reduced, and high-speed color printing can be realized.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

(Embodiment 1) FIG. 1 is a flowchart showing an example of the operation of the color printing apparatus according to the first embodiment of the present invention, and FIG. 2 shows the color printing apparatus of the present embodiment. It is a conceptual diagram which shows an example of a structure.

As illustrated in FIG. 2, the color printing apparatus 205 according to the present embodiment includes a printer controller 206 that performs control operations such as data exchange with the host computer 201, and a printer controller 206. The photoconductor 21 based on the generated bitmap data
3, a laser 212 for forming an electrostatic latent image on the photosensitive member 21,
An image of each process color formed by attaching color toner of each process color to the electrostatic latent image on 3 is transferred,
It includes an intermediate transfer drum 214 for printing on a sheet of paper coming from a paper feed section 216.

In this case, the printer controller 206
Is the application 2 on the high-level computer 201
A color identification unit 207 that extracts information such as the number of colors included in the RGB data 204 from the RGB data that is created in 02 and that arrives via the printer driver 203, and the incoming RGB data for full-color printing by normal conversion. CMYK conversion function 20 to convert to CMYK data
8, the CMYK conversion table 209 described later is referred to, and the RGB data 204 is converted into one or two process colors according to the number of colors included in the RGB data 204 and the mixed state of a plurality of colors. CMYK forcibly converted to
The forced conversion function 210 is provided.

An example of the operation of the color printing apparatus according to this embodiment will be described below.

In the flow chart illustrated in FIG. 1, document data created by the computer 201 by various applications 202 is converted into RGB data via the printer driver 203.
The process on the color printing device 205 side after the data 204 is created and transmitted to the color printing device 205 is shown.

First, the printer controller 206 receives the RGB data 204 (step 11).

Next, the printer controller 206 discriminates the color used in the received RGB data 204 by the color discriminating means 207 (step 12) and judges whether the color used is only black (step 12). 13).

When the color used in the RGB data 204 is only black (branch 13A), the CMYK conversion function 208 changes the normal RGB data 204 to CM.
After conversion into YK data 211 (step 15), bitmap data is generated (step 17). Here, it is judged whether the end of the data has been reached (step 18), and if it is not the end of the data (branch 18A), the printer controller 206 receives the next data (step 11), and then performs the above-mentioned processing (steps 12-18). Repeat until the end of data. When the data is completed (branch 18B), the printing process (step 19) is performed.

When the color used in the RGB data 204 is not only black (branch 13B), it is judged whether a color other than black can be converted into each process color (C, M, or Y) (step 14). . Specific criteria for determining whether or not conversion is possible will be described later with reference to FIG.

As an example of conversion, there is a case where a color other than black is used as a point color in a document, such as a ruled line of a table or an emphasis of a significant item description.

If conversion is possible (branch 14A), R
The colors used in the GB data 204 are forcibly converted into respective process colors by the CMYK forced conversion function 210, for example, by using the CMYK conversion table 209 (step 16), and then bitmap data is generated ( Step 17) is performed. Here, it is judged whether the end of the data has been reached (step 18), and if it is not the end of the data (branch 18A), the printer controller 206 receives the next data (step 11), and then repeats the processes 12 to 18 until the end of the data. repeat. When the data is completed (branch 18B), the latent image is formed on the photoconductor 213 by the laser 212, the toner 215 is applied, and the intermediate transfer drum 21 is formed.
Printing processing such as formation of a color image on the recording medium 4 and transfer of the color image onto paper is performed (step 19).

The conversion process to the forced process color executed by the color printing device 205 can be carried out, for example, by providing the CMYK conversion table 209 in the color printing device 205. The CMYK conversion table 209
The example will be described below with reference to FIG.

The CMYK conversion table 209 in this embodiment is a) basic form according to the mixture ratio of RGB colors,
It can be roughly divided into three types, b) expanded type and c) full color mode.

When one color in the RGB data is 100% and the other colors are not mixed, the basic form of a) is used and R
Convert each GB color into each process color.

When one color in the RGB data is mixed at a ratio of 90% or more and the other color is 10% or less, RGB is mixed.
When all the three colors are mixed at a ratio of 90% or more or 10% or less, the expanded form of b) is used to convert each RGB color into each process color.

If neither of the above applies,
In the full-color mode of c), the forced conversion process by the color printing device is not performed, and the received data is printed faithfully.

The process colors after conversion shown in Tables a) and b) are merely examples, and may be converted into other process colors.

If conversion is not possible (branch 14B),
After converting the normal RGB data 204 to CMYK data 211 using the CMYK conversion function 208 (step 1
5), generate bitmap data (step 17). Here, it is judged whether the end of the data (step 1
8), if not the end of data (branch 18A),
After receiving the next data (step 11), the printer controller 206 repeats the processes 12 to 18 until the end of the data. When the data is completed (branch 18B), the printing process (step 19) is performed (including the case of c)).

In the above description, step 1 in FIG.
In the process of No. 4, if the conversion cannot be performed by the CMYK conversion table 209 (branch 14B), the CM
Although the normal data conversion processing using the YK conversion function 208 is performed, the present invention is not limited to this, and the RG is not restricted by the conversion conditions set in the CMYK conversion table 209.
The number of process colors used in the CMYK data 211 may be suppressed by forcibly converting a color other than black in the B data 204 into each process color by the CMYK forcible conversion function 210 (step 16). .

As described above, according to the color printing apparatus of this embodiment, the CMYK forced conversion function 210 is newly provided in addition to the ordinary CMYK conversion function 208, and the number of colors included in the RGB data 204 coming from the outside is included. The RGB data 204 according to the process color C,
Since any one of M and Y is forcibly converted to a combination of two colors or a maximum of two colors, the number of process colors used in the actual printing operation can be minimized to reduce the number of operations of the photoconductor 213. Therefore, high-speed color printing can be realized.

For example, the small color printing device 205 can print relatively simple color data containing only a small number of colors other than black at high speed.

Further, resources such as color toner can be saved.

(Embodiment 2) Next, referring to FIG.
A color printing apparatus according to the second embodiment of the present invention will be described. FIG. 4 shows a printer controller 40 for controlling data exchange with a host computer 401 in a color printing apparatus according to a second embodiment of the present invention.
It is a conceptual diagram which takes out and shows 2. The configuration other than the printer controller 402 is the same as that of the above-described first embodiment, and therefore the illustration thereof is omitted.

In the above-described first embodiment, the CMYK conversion table 408 (209 in FIG. 2 described above) and CMY.
When forced conversion is performed by the K forced conversion function 409 (210 in FIG. 2 described above), all process colors may be used as a result. In this case, CMYK
Since it is difficult to realize high-speed printing by suppressing the number of process colors used in the data 412, it is better to execute normal full-color printing based on the original data 403 to obtain a print result that meets user needs. Is considered to be obtained.

Therefore, in the second embodiment, when all the process colors are used, the CMYK compulsory conversion function 409 sets the process color bitmap data 412.
When creating (412C, 412M, 412Y, 412K), used color flags 410 (410C, 410M, etc.) of each process color provided in the printer controller 402.
410Y, 410K), the used color grasping function 411 grasps the number of process colors used in the CMYK data. When all process colors are used, C by CMYK forced conversion function 409
Cancel the forced conversion process to MYK data.

At this time, the original data 4 is stored in the data buffer 405 existing in the printer controller 402.
If 03 remains, based on that data, CMY
Normal CMYK conversion processing using the K conversion function 407 is executed to create process color bitmap data 412.

If the original data 403 does not remain, the communication means 404 is used to make the computer 40.
At the same time as requesting 1 to retransmit the original data 403, the retransmission request flag 414 is turned ON. The resend request flag 414 is used to identify the original data 403 previously sent and the resent original data 403 ′. When the resend request flag is ON, resend original data 40
After the color 3'is used to identify the color used in the RGB data by the color identification means 406, a normal CMYK conversion process using the CMYK conversion function 407 is executed to create full-color bitmap data 412.

The printing process such as color latent image formation by the laser 413 after the creation of the bit map data 412 is the same as the case where the CMYK forced process is executed in the first embodiment described above.

(Third Embodiment) FIG. 5 is a conceptual diagram showing an example of the configuration of a printer controller in a color printing apparatus according to a third embodiment of the present invention. In the case of the third embodiment, the application 502 and the printer driver 503 on the host computer 501 are used.
The data that arrives at the color printing apparatus via the CMYK data 504 is already the first
Is different from the embodiment of the present invention.

Correspondingly, the printer controller 506 of the present embodiment has the color identification means 507 for identifying the number of colors in the CMYK data 504 and the CMYK data 504.
A plurality of colors other than black in the image are forcibly converted into CMYK data 504 'of one or two colors, and the bitmap data 508 (508C, 508M, 50C) of the process color is forcibly converted.
8Y, 508K) generating CMYK forced conversion function 50
5 is provided.

Thus, even when the data coming from the high-order computer 501 is already in the CMYK data 504 format, high-speed color printing can be realized in the case of relatively simple color data with a small number of colors. Will be possible.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above-mentioned embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say.

For example, in each of the above-described embodiments, the case where RGB data is converted into CMYK data or CMYK data is converted into CMYK data by the printer controller in the color printing apparatus has been described.
It is also included in the present invention to execute the above-mentioned forced conversion processing by a printer driver operating on a computer such as C. It is obvious that the same effect can be obtained in this case as well.

[0050]

According to the color printing apparatus of the present invention, the number of operation of the photoconductor is reduced by suppressing the number of process colors used during printing to a necessary minimum, and high-speed color printing can be realized. The effect is obtained.

Further, there is an effect that simple color data having a relatively small number of colors can be printed at high speed.

Further, there is an effect that resources such as color toner can be saved.

[Brief description of drawings]

FIG. 1 is a flowchart showing an example of the operation of a color printing apparatus according to a first embodiment of the present invention.

FIG. 2 is a conceptual diagram showing an example of a configuration of a color printing apparatus according to the first embodiment of the present invention.

FIG. 3 is a conceptual diagram showing an example of a CMYK conversion table in the color printing apparatus according to the first embodiment of the present invention.

FIG. 4 is a conceptual diagram showing a printer controller for controlling transmission / reception of data with a host computer in a color printing apparatus according to a second embodiment of the present invention.

FIG. 5 is a conceptual diagram showing an example of a configuration of a printer controller in the color printing apparatus according to the third embodiment of the present invention.

FIG. 6 is a flowchart showing an example of a possible conventional color printing process.

FIG. 7 is a conceptual diagram showing an example of a configuration of a possible conventional computer and a color printing apparatus.

[Explanation of symbols]

201 ... Computer, 202 ... Application, 2
03 ... printer driver, 204 ... RGB data, 20
5 ... Color printing device, 206 ... Printer controller,
207 ... Color identification means, 208 ... CMYK conversion function (first
CMYK conversion function), 209 ... CMYK conversion table, 210 ... CMYK forced conversion function (second CMYK conversion function), 211 ... CMYK data, 212 ... Laser, 213 ... Photoconductor, 214 ... Intermediate transfer drum, 215
... Toner, 216 ... Paper feeding section, 401 ... Computer, 4
02 ... printer controller, 403 ... original data, 403 '... resend original data, 404 ... communication means, 405 ... data buffer, 406 ... color identification means, 4
07 ... CMYK conversion function, 408 ... CMYK conversion table, 409 ... CMYK forced conversion function, 410 ... Used color flag, 411 ... Used color grasping function, 412 ... CMYK data (bitmap data), 413 ... Laser, 414
... resend request flag, 501 ... computer, 502 ... application, 503 ... printer driver, 504 ...
CMYK data, 504 '... CMYK data, 505 ...
CMYK forced conversion function (third CMYK conversion function), 5
06 ... Printer controller, 507 ... Color identification means.

Claims (3)

[Claims] 1. A color identification means for identifying color information represented by RGB contained in original data input from the outside, and the RG for the color information in the original data.
A first CMYK conversion function for converting the B expression into a full-color CMYK expression, and a color other than black included in the color information is one of cyan (C), magenta (M), and yellow (Y) or A color printing apparatus having a second CMYK conversion function for forcibly converting into two process colors. 2. The color printing apparatus according to claim 1, wherein the second CMYK conversion function is R (red), G (green), B (blue) obtained from color information by the RGB representation.
The color printing apparatus is characterized in that the color mixture is converted into one or two process colors by comparing the mixture ratio of each color with a predetermined threshold value. 3. A color identifying means for identifying color information in CMYK representation included in original data input from the outside, and a color other than black included in the color information in the original data as cyan (C). And a third CMYK conversion function for forcibly converting into one or two process colors of magenta (M) and yellow (Y).