Facsimile and static presentation processing – Static presentation processing – Attribute control
Reexamination Certificate
1997-04-09
2002-02-19
Zimmerman, Mark (Department: 2671)
Facsimile and static presentation processing
Static presentation processing
Attribute control
C358S001120, C358S001140, C358S001100, C358S501000, C358S503000, C358S518000, C345S440000
Reexamination Certificate
active
06348977
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to color data processing by which a color printer prints color data using Y (Yellow), M (Magenta), C (Cyan), K (blacK) colors, and a control program and memory medium therefor.
2. Related Background Art
FIG. 1
is a block diagram showing the arrangement of a system having a host computer and a color printer such as a color laser beam printer. Referring to
FIG. 1
, host computer
101
is connected to color laser beam printer control unit
100
(shown by broken line) in the color laser beam printer via an unnumbered connecter. Control unit
100
receives both commands (for example, a paper eject command) and data (for example, Red, Green and Blue data or black-and-white data) from host computer
101
, and processes the commands and data so as to cause an unnumbered print engine to print via print engine interface
105
.
CPU
103
controls the entire control unit
100
. Reception buffer
102
temporarily stores received information including commands and data and so forth received from host computer
101
. Program ROM
104
stores a control program shown by flow chart in
FIG. 2
, rendering program
108
(a rendering process in step S
205
in
FIG. 2
) and color converting program
109
(a converting process in step S
204
in FIG.
2
). Font ROM
106
stores character fonts to make character images. RAM
101
is used as a work area to store converted YMCK data and so on while the program is operating and image storage area
110
to store an image. Print unit
105
outputs YMCK image to the color printer engine. Furthermore, a system power supply (not shown) supplies power to control unit
100
.
An operation of color laser beam printer control unit
100
shown in
FIG. 1
will be described with reference to the flow chart shown in FIG.
2
.
FIG. 2
is a conventional flow chart showing the flow of color convert processing in color laser beam printer control unit
100
. The process steps shown in
FIG. 2
are stored program process steps that are stored in a computer readable memory medium, in this case in program ROM
104
.
In step S
201
, in response to initial applications of power, CPU
103
initializes image storage area
110
. In step S
202
, CPU
103
reads received information in single unit codes from reception buffer
102
, which stores commands and data received from host computer
101
. In step S
203
, CPU
103
determines if the read information is a paper eject command. If it is determined in step S
203
that the read information is not a paper eject command, or some other type of command, CPU
103
determines that the read information is data and converts the data into image data for use by the printer engine. Where the data is RGB color data, CPU
103
converts the RGB data into YMCK data as color space of the color printer engine using the color converting program
109
in step S
204
.
The color convert process to convert R (red), G (green), B (blue) data into YMCK data, is executed using the 4×3 matrix as follows.
[
Y
M
C
K
]
=
[
4
×
3
matrix
]
[
R
G
B
]
Further, if it is determined that the read data is black-and-white data, the black-and-white data is converted into YMCK data by converting the black-and-white data into K data only and by setting the YMC data to 0 in step S
204
.
In step S
205
, CPU
103
renders an image based on YMCK data converted in step S
204
using rendering program
108
, stores the image by color in image storage ares
110
and flow returns to step S
202
to receive new information.
On the other hand, if it is determined in step S
203
that the information is a paper eject command, CPU
103
outputs the rendered YMCK image in image storage area
110
to print unit interface
105
to print the YMCK image. The color laser beam printer engine prints YMCK image using Y (Yellow), M (Magenta), C (Cyan) and K (blacK) color toner.
In the above case, even if host computer
101
sends RGB data for a pure gray color in which the RGB components are equal (Red=Green=Blue), the RGB data will be converted into YMCK data. Thus, the gray color is expressed by mixed YMCK data. This causes a sense of incongruity as compared to the case where black color is expressed by K (black) data only.
In addition, black-and-white data is converted into YMCK data by converting the black-and-white data into K (black) data only and by setting the Y,M,C data to 0 (zero) in step S
204
.
This causes a problem that size of the converted black-and-white data (intermediate data) becomes four times as large as needed since the Y, C and M components are zero. The converted black-and-white data is stored in work area in RAM
101
. And then image is rendered based on the converted black-and-white data.
SUMMARY OF THE INVENTION
The present invention has been made in consideration of the above circumstances, and provides a color data processing apparatus, a method of controlling a process of converting color data, and/or a memory medium storing a controlling program, which discriminates the type of a received data, and which executes, based on the discriminated type of received data, a first process to convert the received data into Y (yellow), M (magenta), C (cyan) and K (black) color data, or an second process to convert the received data into K data.
In preferred embodiment of the invention, when the received data is color data for R (red), G (green) and B (blue) colors, and the color data for the R, G and B colors have equal or substantially equal values, the executing means executes the second process to convert the received data into K data, thereby rendering an image based on data converted by the second process.
Likewise, when the received data is color data for R, G and B colors, and the color data for the R, G and B colors do not have equal or substantially equal values, the executing means executes the first process to convert YMCK data, thereby rendering an image based on data converted by the first process.
It is also preferable, when the received data is black-and-white data, the executing means executes the second process to render an image based on data converted by the second process.
Likewise, when the received data is not black-and-white data, the executing means executes the first process to render an image based on data converted by the first process.
In particularly preferred embodiments, when the executing means renders an image based in data converted by the second process the executing means also sets values for Y, M and C data identically to 0.
Further objects, features and advantages of the present invention will become apparent from the following detailed description of the embodiments of the present invention with reference to the accompanying drawings.
REFERENCES:
patent: 5345320 (1994-09-01), Hirota
patent: 5729624 (1998-03-01), Tanioka et al.
patent: 5768411 (1998-06-01), Shu et al.
patent: 6118558 (2000-09-01), Ohashi et al.
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Sealey Lance W.
Zimmerman Mark
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