JPH0225191A - Color printer - Google Patents

Abstract

PURPOSE:To print out a still picture led in succession in a print time by providing a storage means able to store a color video signal over at least one field to a color printer configuration. CONSTITUTION:A color video signal is separated into a luminance signal Y and a chrominance signal C at a separator circuit 34, after the signal C is demodulated into color difference signals R-Y, G-Y, B-Y by a demodulation circuit 35, the result is stored in a memory 39 in a form of a digital signal via an A/D converter circuit 36. On the other hand, the signal Y is stored in a memory 40 in a form of a digital signal via an A/D converter 37. The signal Y and the signals R-Y, G-Y, B-Y read out of the memories 39, 40 able to store a color video signal by one field are added by adder circuits 41-43 and the synthesized primary color signals R, G, B are sent to a printer 45 sequentially by a multiplexer 44.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is applied to a color printing device, for example, a video playback device, etc., in which a color video signal is stored once, and after being stored, it is read out to produce an image corresponding to the color video signal. The present invention relates to a color printing device that prints images.

Related Art 2 (2I is a block diagram of a conventional color printing apparatus 1. The conventional color printing apparatus 1 includes an analog signal processing section 2 and a digital signal processing section 3. The color video signal to be printed, which is an analog signal, is
When inputted from an input terminal 4 connected to a video output terminal of a video playback device or the like, the color video signal is inputted to a separation circuit 5 via a signal line sl1.

In order to generate primary color signals R, G, and B of red, green, and blue necessary for printing an image corresponding to the color video signal, the input color video signal is processed in the separation circuit 5 in the separation circuit 5. (The l signal is separated into a luminance signal Y representing the brightness of the color and a chroma signal C representing the saturation and hue of the color.

The chroma signal C is sent to the demodulation circuit 6 via the signal line se2. In the demodulation circuit 6, the chroma signal C is demodulated into primary color signals of red, green, and blue hues, and becomes color difference signals RY, G-Y, and BY.

The color difference signals R-Y, G-Y, and B-Y demodulated to produce the primary color signals R, , G, and B are sent to signal lines sl, respectively.
3. sl 4. The luminance signal Y is sent to the RGB matrix circuit 7 via sl 5, and the luminance signal Y separated by the separation circuit 5 is sent to the l'2GB matrix circuit 7 via signal line s16.

On the other hand, each of the color difference signals R-Y, G-Y, B-Y and the luminance signal Y are connected to a signal line sl7. sl 8,
sl9. The signal is sent via sl 10 to another video processing circuit 8 for processing. Other video processing circuits 8, such as a CRT (cathode ray tube), perform operations such as displaying still images to be printed.

Luminance signal Y input to R, G B matrix circuit 7
and each color difference signal R-Y, G-Y, B-Y is synthesized,
Derive primary color signals R, G, and B. The carried primary color signals R, G, and B are transmitted to each signal line sl11. sl 1
2. It is sent to the switch unit 9 via sl 1.3.

The switch part is made up of an analog switch such as a transistor, and when the analog switch is switched under the control of a control part (not shown), the input primary color signals R, G, and B are sequentially sent to the switch part by IFJ. 9
are sent to the analog/digital converter (hereinafter referred to as "A/D9: converter J") 10 via the signal line 5e14.Each primary color signal R, sent to the A/D converter 10
G and B are converted from analog signals to digital signals.

The primary color signals R, G, and B converted into digital signals are sent to the printing device 11 via a signal line 5115, and a printing operation is performed.

In the color printing apparatus 1 described above, the primary color signals R and GB necessary for printing are directly derived from the color video signal input to the input terminal 4 without being stored in the storage means, and the printing operation is performed. It is difficult to print a subsequently derived still image within the printing operation time determined by the configuration of the color printing apparatus 1.

In order to solve the above-mentioned problems, the configuration of the conventional color printing apparatus 1 is further provided with a storage means capable of storing at least one field worth of color video signals, so that the color image signals can be stored continuously within the printing operation time. It is now possible to print still images derived from

No. 3 [] is a block diagram of the configuration of Ike's conventional color printing device 14, and No. 2 c? This is a configuration in which a storage means is inserted into the structure of the color printing apparatus 1 of I.

From FIG. 2 onwards, the same reference numerals indicate the same or corresponding parts.

In the color printing apparatus 1 shown in FIG. 2, the storage means is provided on the signal line where the amount of information of the color video signal to be stored is as small as possible. ! :14 is taken into consideration. As a result, the luminance signal Y on the signal line 816 input to the RGB matrix @path 7 and each signal line sZ 3. The sum of the color difference signals R-Y and G-Y B-Y on sl 4 and sl 5 is the signal with the least amount of information among the color video signals representing one still video, so these The luminance signal Y and each of the color difference signals R-Y, G-Y, and B-Y are stored in a storage means on the line, and then the derived still image is printed.

The storage means is a random access memory RA that can store and read color video signals as digital signals.
A memory 20.21 such as M is used. Since the memory 20.21 for digital signal processing is inserted into the analog signal processing unit 2, the input side of the memory 20.21 has an A/
A D converter 22, 23 is provided, and the memory 20.
On the output side of 21, there is a digital/analog converter (hereinafter referred to as
[D/A conversion converter-U) 24.25 is provided.

Therefore, the configuration of the color printing device 14 includes a first analog signal processing section 15, a first digital signal processing section 16, a second analog signal processing section 17, and a second digital signal processing section 1.
Contains 8.

By the same process as the second [21st color printing device 1],
Separated and fl Fl each color difference signal R-YG-
Y, B-Y and luminance signal Y are transmitted through signal lines s13 and sl4, respectively. The signals are input to A/D converters 22, 23 via sl 5 and signal input s16, and are converted from analog signals to digital signals. Each color difference signal R, -Y is converted into a digital signal.

G Y, B Y and the luminance signal Y are connected to the signal line sl 16. st' 17. via sl 18 and signal line 8119 to memory 20.21.

Part 1, each color difference signal read out R-Y, G'l'B-
Y and the luminance signal Y are on signal line 5120, sN 2
1. sl! 22 and signal line 5123,
The signals are input to D/A converters 24 and 25 and converted from digital signals to analog signals.

Each color difference signal R-Y is converted into an analog signal again.

G-Y, B-Y and luminance signal Y are connected to signal line sl
24 sl 25. sZ 26 and signal line 5f
27, the primary color signals R, G, and B are sent to the RGB matrix circuit 7, and as in the conventional color printing apparatus 1 described above, the primary color signals R, G, and B are combined. The images are sequentially sent one by one to the printing device 11 via the A/D converter 10, and a printing operation is performed.

Problems to be solved by the inventionConventional color photographic bag r! ! , 14, it is possible to print a still image that is subsequently derived within the printing operation time, but the conversion process is difficult due to the process of signal conversion from analog to digital and from digital to analog, which is performed several times. Conversion errors occurring in subsequent signals tend to increase, and as a result, the image quality of printed still images tends to deteriorate.

The purpose of the present invention is to solve the above-mentioned problems,
To provide a color printing device capable of reducing the number of signal conversions, reducing conversion errors, preventing deterioration of the image quality of printed color development, and improving the quality of the printing device.

Means for Solving the Problems The present invention provides a signal conversion means for converting an analog luminance/color difference signal representing a color image into a digital luminance/color difference signal, and a storage means for storing the digital luminance/color difference signal from the signal conversion means. a means for synthesizing a digital color signal from the digital luminance/color difference signals read from the storage means; a switching means for sequentially switching and outputting each of the plurality of color signals output from the synthesizing means; and the switching means. This is a color printing apparatus characterized in that it includes a printing means for performing a printing operation based on a digital color signal from a color printing apparatus.

Function According to the present invention, after the analog luminance/color difference signal representing color development is converted into a digital luminance/color difference signal by the signal conversion means, the digital color signal is stored by the storage means. Each digital color signal is synthesized from the digital luminance/color difference signals read from the storage means for printing, and is sequentially switched by the switching means and output to the printing means. In the printing means, a printing operation is performed based on each digital color signal. Therefore, the number of A/D or D/A conversions of video signals is reduced, signal errors caused by conversion are also reduced, and color images with good image quality can be printed.

Embodiment FIG. 1 is a block diagram of a color printing apparatus which is an embodiment of the present invention. The color printing device 30 includes an analog signal processing section 31 and a digital signal processing section 32. When the color video signal to be printed, which is an analog signal, is input to the input terminal 33 connected to the video output terminal of a video playback device, etc., the signal line 5Z30
The signal is input to the separation circuit 34 via.

In order to generate primary color signals R, G, and B required for printing an image corresponding to the color video signal as described later, the input color video signal is processed by the separation circuit 34 to determine the brightness of the color. and a chroma signal C, which represents the saturation level and hue of the color. The chroma signal C is sent to the demodulation circuit 3 via the signal line 5131.
5. In the demodulation circuit 35, the chroma signal C
The hue is demodulated into primary color signals of red, green, and blue.
The color difference signals are R-Y, G-Y, and B-Y.

The demodulated color difference signals R-Y, G-Y, B-Y are transmitted to each signal line sl 32. sl 33. s7! 34 to an A/D converter 36, and is converted from an analog signal to a digital signal for subsequent processing in the digital signal processing section 32. Further, the luminance signal Y separated in the separation circuit 34 is sent to A via a signal line 5135.
The signal is sent to the /D converter 37, where it is similarly converted from an analog signal to a digital signal. On the other hand, the color difference signals R-Y, G-Y, B-Y and the luminance signal Y, which are analog signals, are transmitted through the signal lines sl 36, 5137. It is also sent to other video processing circuits 38 for processing via st'38 and signal line 5N39. The other video processing circuit 38 uses, for example, a CRT (cathode ray tube) to display a still image of a color video to be printed.

Each color difference signal R-Y, G-Y, B-Y passed through the A/D converter 36 and converted into a digital signal is transmitted to each signal line sl.
40. sl 41. sl 42 to three memories, such as random access memory RAM, for storage. Further, the 1-variant signal Y that has passed through the A/D 2ffi unit 37 is also sent to a similar memory 40 and stored therein via the signal line and 5Z43. The memory 39.
40 has a storage capacity capable of storing at least one field's worth of color video signals.

The stored color difference signals RY, G-Y, B-Y and luminance signal Y are read out and the color difference signals RY are read out.

In order to print an image corresponding to the color video signal which is the source of G-Y, B-Y and the luminance signal Y, the necessary information for printing is calculated from the color difference signals RY, GY, B-Y and the luminance signal Y. The primary color signals R, G, and B are combined. In this embodiment, first, the red color difference signal R-Y is sent from the three memories to the adder circuit 41 via the signal line 5144, and the luminance signal Y is sent from the memory 40 to the signal line 5144.
147s148 to the adder circuit 41. In the addition circuit 41, addition processing is performed between the input color difference signal R-Y and the luminance signal Y, and a red primary color signal R is synthesized. Through similar processing, in the adder circuit 42, the green color difference signal G-Y is inputted from the three memories via the signal line 5145, and the luminance signal Y from the memory 40 is inputted to the signal line sl47. sl 49, addition processing is performed between the input color difference signal G-Y and the input luminance signal Y, and a green primary color signal G is synthesized.

Further, in the adder circuit 43, the blue color difference signal B-Y is inputted from the memory 39 via the signal line 3146, and the luminance signal Y is inputted from the memory 40 via the signal line Sρ47.
．． An addition process is performed between the color difference signal B-Y and the luminance signal Y inputted through the sZ 50, and a blue primary color signal B is synthesized.

The obtained primary color signals R, G, and B are sent to each adding circuit 41.4.
2.43 to each signal line st'51. s152, se
53 to the multiplexer 44. A switching means is provided in the multiplexer 44,
The input primary color signals R1G and B are sequentially switched and sent one by one to the printing device 45 via the signal line sl 54. In this printing device 45,
The primary color signals R, G, and B input sequentially are processed by the printing device 45 as complementary colors (cyan, magenta,
After the signal is converted into a signal corresponding to (yellow), the cyan, magenta, and yellow inks on the color ink sheet are attached to the printing position on the photographic paper by controlling a thermal printer head, etc., and the colors are mixed together. An action is taken.

The above-mentioned adhesion operation is performed for each of the three colors cyan, magenta, and yellow of the color ink sheet for each horizontal scanning line of a still image of a color image to be printed, and is repeated for the number of horizontal scanning lines, so that The printing motion fj of one still image is completed.

According to the above-described structure, it is possible to print still images that are subsequently derived within the printing operation time by intervening a memory that stores signals.

Furthermore, since the signal is A/D converted only once, conversion errors occurring in the signal can be minimized. Therefore, deterioration of the image quality obtained by printing can be suppressed.

Effects of the Invention According to the present invention, the AlO2 conversion of the signal from inputting the color video signal to the digital color signal at the time of printing is only performed at a stage before the signal is stored in the storage means. , A/D conversion, and D/A conversion can be minimized, thereby suppressing deterioration of the image quality of printed color images and improving the quality of the printing apparatus.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a color printing device according to an embodiment of the present invention, FIG. 2 is a block diagram of a conventional color printing device 1, and FIG. 3 is another conventional color printing device 1.
FIG. 4 is a configuration block diagram of No. 4. 30...Color printing device, 36.37...A/D converter, 39.40...Memory, 44...Multiplexer, 45...Printing device agent Patent attorney Keiichi Saikyo

Claims (1)

[Scope of Claims] Signal conversion means for converting analog luminance/color difference signals representing color images into digital luminance/color difference signals; storage means for storing the digital luminance/color difference signals from the signal conversion means; and the storage means. means for synthesizing a digital color signal from digital luminance and color difference signals read out from the digital luminance and color difference signals; a switching means for sequentially switching and outputting a plurality of color signals output from the synthesizing means; and a digital color signal from the switching means. 1. A color printing apparatus, comprising: a printing means that performs a printing operation based on the above.