JPH0326819B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a color printing device capable of performing color printing using television signals.

(Prior art and problems) Television signals (hereinafter referred to as TV signals)
As a color printing device that can perform color printing using a printer (hereinafter abbreviated as ), there is a device that was previously applied for a patent as Japanese Patent Application No. 1983-95627 by the applicant company, and this already proposed color printing device By using a television signal, it was possible to obtain high-quality color printed matter using television signals, but the color printing devices that have been proposed only use yellow, magenta, and cyan inks for printing. Because black ink was not used, some images were unsatisfactory depending on the content.

Therefore, we created a prototype color printing device that can always produce satisfactory printed matter by using four printing inks: yellow, magenta, cyan, and black.
Color printing apparatuses naturally require longer printing times than three-color printing apparatuses, so it was desired to shorten the printing time.

(Means for Solving the Problems) The present invention uses three primary color signals of red, green, and blue of a TV signal as R, G, and B, and each of the above primary color signals corresponds to a primary color with a saturation of 100%. When the state of
three color signals as respectively indicated by
Ye, M, Cy and the brightness signal Y of the TV signal is 100% white
If the state of is expressed as 1, then Bk≡1−
Obtain a black signal Bk as indicated by Y, and convert the three color signals Ye, M, Cy, and the black signal Bk described above into
When color printing is performed using yellow, magenta, cyan, and black inks that correspond to the three color signals and black signal described above, the three color signals used for color printing are as follows. The above-mentioned problems are solved by using a black signal consisting only of low-frequency signal components, and by using a black signal consisting only of high-frequency signal components for color printing. This allows for color printing to be obtained.

(Embodiment) Hereinafter, specific details of the color printing apparatus using TV signals of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a block diagram of essential parts of an embodiment of a color printing apparatus using TV signals according to the present invention.
In FIG. 1, 1 is an input terminal for a television signal to be printed in color, and in the illustrated example, the input terminal 1 is a band-sharing multiplexer for a luminance signal Y and a carrier color signal. A TV signal (for example, an NTSC composite color TV signal) is provided.

The TV signal supplied to the input terminal 1 is converted into a luminance signal Y and color difference signals R-Y, B-Y in a signal processing circuit (decoder) DEC, and then converted into a luminance signal Y and color difference signals R-Y, B-Y. -Y and other matrix circuits MTX
The primary color signals are R, G, and B.

The luminance signal Y is given to a high-pass filter HPF (hereinafter referred to as high-pass filter HPF), and from the high-pass filter HPF, a high-frequency signal component of the luminance signal Y, for example, a frequency band of 500 KHz to 4 MHz is output. luminance signal Yh
is output.

Also, the 3 output from the matrix circuit MTX
The three primary color signals R, G, and B are passed through low-pass filters (hereinafter referred to as low-pass filters) LPFr, LPFg, respectively.
The LPFb generates primary color signals Rl, Gl, and Bl occupying a frequency band of 500 KHz or less, for example.

Luminance signal Yh output from high-pass filter HPF
The primary color signals Rl, Gl, Bl, etc. output from the low-pass filters LPFr, LPFg, and LPFb are processed by individual analog-to-digital converters (hereinafter referred to as AD converters) ADCy, ADCr, ADCg, and ADCb, respectively. It is converted into digital signals Yhd, Rld, Gld, and Bld and stored in the digital memory DM.

AD converters ADCy, ADCr, ADCg, ADCb, digital memory DM, and changeover switch SW (described later)
Control signals necessary for the operation of each of the constituent parts are given to each of the above-mentioned constituent parts from the control signal generation circuit CSG, and each of the above-mentioned constituent parts performs the required operation at a predetermined timing.

The digital signals stored in the digital memory DM are read out in a predetermined order and sent to the signal conversion circuit SCD.
After being converted into a printing signal by Print on .

The manner in which signals are read from the digital memory DM depends on whether the recording (printing) manner in the recording unit RE is performed in a line-sequential manner, a field-sequential manner, or a dot-sequential manner. Needless to say, the switching mode of the changeover switch SW is adapted to the recording mode in the recording section RE described above.

The signal conversion circuit SCD described above converts red and red TV signals.
Let the three primary color signals of green and blue be R, G, and B, and when the state in which each of the above primary color signals corresponds to a primary color with 100% saturation is represented by 1, the above three primary color signals are M≡ Three signals Ye, as denoted by 1-G, Ye≡1-B, Cy≡1-R, respectively.
The digital signal Bld given to the signal conversion circuit SCD is converted into the printing signal Yeld from the signal conversion circuit SCD. The digital signal Gld is output as ≡(1-Bld) and is also given to the signal conversion circuit SCD.
is the printing signal Mld≡(1
−Gld), and further signal conversion circuit
The digital signal Rld applied to the SCD is outputted from the signal conversion circuit SCD as a printing signal Cyld≡(1−Rld).

In addition, the signal conversion circuit SCD converts the brightness signal Y of the TV signal into a black signal Bk as shown by Bk≡1−Y, where 1 represents a state in which the brightness signal Y of the TV signal is 100% white. Since the signal conversion circuit is configured to have conversion characteristics such as
The digital signal Yhd applied to the SCD is outputted from the signal conversion circuit SCD as a printing signal Bkhd≡(1−Yhd).

As in the configuration example shown in Figure 1, the high-frequency signal component Yh of the luminance signal Y and the low-frequency signal components Rl, Gl, Bl of each color signal R, G, B, etc. are converted into digital signals by an AD converter. In the case where signal processing is performed using a digital signal, an inexpensive digital memory can be used as the memory, and the signal conversion operation in the signal conversion circuit SCD can be performed extremely easily. When printing on paper with printing ink by giving a signal to the recording unit, an operation type that turns the recording element on and off is used, and the recording element corresponds to the digital value indicated by the printing signal. By operating the recording element a number of times, the ink adhesion area and/or ink adhesion amount (density) within one pixel (one picture element) can be changed according to the number of times the recording element is operated, so that the recorded image can have the desired gradation. It can be assumed that the

It goes without saying that the number of gradations obtained in the recorded image described above is determined by the number of bits of the printing signal, but if it is assumed that, for example, 64 gradations are required in the recorded image, In this case, the printing signal is a 6-bit digital signal, and the AD converter used is one that can convert the analog signal input thereto into a 6-bit digital signal.

By the way, it has been statistically confirmed that the signal level of the high-frequency signal component of a TV signal is lower than the signal level of the low-frequency signal component, so as mentioned above, the signal level of the high-frequency signal component is lower than 0.5MHz. Regarding the low-frequency signal component of the color signal that has been band-limited,
For example, if it is quantized with 6 bits as described above, the high-frequency signal component of the luminance signal having a band of 0.5 M to 4 MHz as described above may be quantized with, for example, 5 bits.

Therefore, as the AD converter ADCy, one that can convert the high frequency signal component Yh of the luminance signal Y into a 5-bit digital signal Yhd is used, and
The AD converters ADCr, ADCg, and ADCb convert the low-frequency signal components Rl, Gl, and Bl of each color signal R, G, and B into 6
It is possible to use a device that can be converted into bit digital signals Rld, Gld, and Bld.

As mentioned above, the digital signal Yhd obtained by AD converting the high-frequency signal component Yh of the luminance signal Y converts the low-frequency signal components Rl, Gl, and Bl of the color signals R, G, and B into AD.
If the converted digital signals Rld, Gld, and Bld are 1 bit less than the digital signals,
The number of bits of the printing signal corresponding to black ink is also one bit less than the number of bits of the printing signal corresponding to yellow, magenta, cyan, etc. inks, so the time required to print four colors is This means that it takes 3.5 times the time required to print one color.

In addition, in an AD converter, the maximum frequency of the analog signal targeted for AD conversion is
It is clear from the sampling theorem that sampling quantization must be performed at a sampling frequency that is more than double the sampling frequency. R, G, B
The highest frequency of low frequency signal components Rl, Gl, Bl is 0.5M
Hz, the sampling frequency in ADCy is 8MHz or more, AD converter ADCr,
The sampling frequency for ADCg and ADCb is
Must be 1MHz or higher.

As mentioned above, the sampling frequency in the AD converters ADCr, ADCg, ADCb, etc. for AD converting the low frequency signal component of the color signal is the same as that of the AD converter for AD converting the high frequency signal component of the luminance signal Y. Although it may be lower than the sampling frequency in ADCy, if the sampling frequency in AD converters ADCr, ADCg, and ADCb is also the same as that in AD converter ADCy, printing signals Yeld, Mld,
Since the Cyld transfer speed can be made the same as the print signal Bkhd transfer speed, printing time can be significantly shortened.

Recording unit that performs recording operations based on printing signals
The RE can be one that uses a thermal head as a recording element, one that uses an inkjet as a recording element, or one that uses various other recording elements. Regarding recording (printing) by
Color transfer paper can also be used.

Figure 2 shows analog memory DMa as memory.
In addition, as a signal conversion circuit, a signal conversion circuit SCDa (for example, a signal conversion circuit using an analog signal) (for example,
A similar configuration to the printing signal generation circuit SCT in No. 95627 may be used), and furthermore, depending on the size of the printing signal, the density of the ink or the amount of ink deposited within the pixel can be adjusted. Recording section RE using a recording element whose area can be changed
This shows an embodiment of the color printing apparatus using TV signals of the present invention, which is configured with the following.
The embodiment shown in the figure can also perform four-color printing in a short printing time. In addition, the signal conversion circuit SCDa outputs Bkh, Yel,
Ml and Cyl are output.

(Effects) As is clear from the detailed explanation above, in the color printing apparatus using TV signals of the present invention, the color signal used for color printing is composed only of low-frequency signal components. In addition, by using a black signal consisting only of high-frequency signal components as the black signal used in color printing, in the color printing apparatus using television signals of the invention of the present application, "the black signal used in color printing is Three color signals Ye, M,
Naturally, the "signal consisting only of low-frequency signal components of the three color signals Ye, M, and Cy used for color printing" used as "Cy" includes the high-frequency signals of the three color signals Ye, M, and Cy. Since it does not contain any color components, in printing using "three color signals Ye, M, Cy used for color printing" in the color printing apparatus using television signals of the invention of the present application, three color signals Ye, M, Cy are used. Fine parts of images are not printed, and therefore, in the color printing device using television signals according to the invention of the present application, the three color signals Ye generated when printing by conventional color printing devices including the device in the cited example are not printed. ，
Ye, M, printed by the high frequency components of M, Cy
Black and white printing is not performed due to color mixing in the minute area of Cy, and the black signal used during color printing in the color printing device using the television signal of the invention of the present application is ``three color signals used for color printing''. The signal consisting only of the high-frequency signal components of Ye, M, and Cy naturally does not include the low-frequency signal components of the three color signals Ye, M, and Cy. When a color printing device prints with "black component Bk consisting only of high-frequency signal components of the three color signals Ye, M, and Cy used for color printing," a large area of the image cannot be printed, and therefore, The color printing device using television signals according to the invention of the present application does not have the problem of overprinting due to black signals that occurs when printing by conventional color printing devices including the cited device, and can be performed using conventional color printing devices. Since the color printing device using television signals of the invention of the present application does not require removing the undercolor from the color signal that has been previously used, the color printing device of the present invention using television signals has good color reproduction. An image in which details are sharply defined by black outlines can be easily obtained in a short printing time, and according to the present invention, the above-mentioned conventional problems can be satisfactorily solved.

[Brief explanation of the drawing]

1 and 2 are block diagrams of different embodiments of the apparatus of the invention. DEC...decoder, MTX...matrix circuit, ADCy, ADCr, ADCg, ADCb...AD converter, DM...digital memory, DMa...analog memory, SCD, SCDa...signal conversion circuit, SW
...Selector switch, RE...Recording section (printing section),
CSG...Control signal generation circuit, P...Paper.

Claims (1)

[Claims] 1 Let the three primary color signals of red, green, and blue of a television signal be R, G, and B, and when 1 represents the state in which each of the above primary color signals corresponds to a primary color with 100% saturation, Ye≡ 1-B, M≡1-G, Cy≡1-R
three color signals as respectively indicated by
Ye, M, Cy and the brightness signal Y of the television signal
When the state of 100% white is expressed as 1,
A black signal Bk as shown by Bk≡1-Y is obtained, and the above three color signals Ye, M, Cy and a black signal Bk are converted into a yellow signal corresponding to each of the above color signals and the black signal. , magenta, cyan, and black ink in a color printing device using television signals, the three color signals used for color printing are the low-frequency signal components of the three color signals used for color printing. 1. A color printing device using a television signal, characterized in that a black signal used for color printing is made of only a high frequency signal component of the black signal.