JPH06197370A - Crt printer - Google Patents

Abstract

PURPOSE:To provide the CRT printer able to print out a color picture with high resolution even when a time required for print is short. CONSTITUTION:In the CRT printer having a black/white CRT 8 receiving individually red, green and blue signals being color picture signals and an optical filter 9 arranged to a tube side of the CRT 8 switched into respectively a red, a green or a blue filter and exposing red, green and blue picture lights obtained individually from the optical filter 9 individually and overlapping onto an instant film 12 through a shutter 11 and an optical system 10, the luminance of a green signal fed to the CRT 8 is set lower than the luminance of the red and blue signals and the exposure time of the red, green and blue picture lights onto the instant film 12 is set so as to obtain an excellent color picture accordingly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CRT printer which prints a color image by separately exposing an instant film with image light of each color using a black and white CRT and an optical filter of each color.

[0002]

2. Description of the Related Art In a black-and-white CRT used in such a CRT printer, when the brightness is increased, the spot of the electron beam on the phosphor becomes large and the focus characteristic is deteriorated, so that the resolution of the color image printed on the instant film is lowered. Therefore, the luminance of each color signal supplied to the CRT is prevented from becoming too high.

Incidentally, the red, green and blue signals R, as shown in FIG. 3, are so arranged that the characteristics of the brightness of the red, green and blue colors of the instant film with respect to the luminance levels of the red, green and blue signals respectively become substantially straight lines. G and B are γ-corrected by the drive circuit of the CRT and then supplied to the CRT. Further, the peak luminance levels of the red, green and blue signals R, G and B are adjusted by the contrast adjusting circuit of the drive circuit of the CRT.

[0004]

However, when the luminance of the luminance signal of each color supplied to the CRT is lowered as in the above-mentioned conventional example, red, green and blue images are obtained so that a good color image can be obtained accordingly. Each exposure time of the light to the instant film has to be lengthened, resulting in a longer printing time.

In view of the above point, the present invention is to provide a CRT printer capable of printing a high resolution color image even if the printing time is short.

[0006]

SUMMARY OF THE INVENTION The present invention is a black and white CRT to which the red, green and blue signals of a color image signal are supplied separately.
8 and an optical filter 9 arranged on the tube surface side of the CRT 8 which can be switched to the red, green and blue filters accordingly, and the red, green and blue images respectively obtained from the optical filter 9 are provided. In a CRT printer in which light is separately superimposed and exposed on the instant film 12 through the shutter 11 and the optical system 10, the brightness of the green signal supplied to the CRT 8 is made lower than the brightness of the red and blue signals, and in accordance therewith, good brightness is obtained. The exposure time of the red, green, and blue image light to the instant film is set so that a color image can be obtained.

[0007]

According to the present invention described above, the brightness of the green signal supplied to the CRT 8 is made lower than the brightness of the red and blue signals, and the red, green and blue image lights are supplied so that a good color image can be obtained accordingly. The exposure time for the instant film 12 is set.

[0008]

Embodiments of the present invention will be described in detail below with reference to FIG. Red, green and blue signals of color image signals are supplied to the black and white CRT 8 separately. On the tube surface side of the CRT 8, there is arranged an optical (color) filter 9 which can be switched to the red, green and blue filters respectively by rotating. Then, the red, green and blue image lights respectively obtained from the optical filter 9 are converted into an optical system (for example, a magnifying lens) 1
0 and a shutter 11 are used to separately expose the color instant film 12 so that a color image is printed. The color filter 9
The rotation and the opening time of the shutter 11 and its timing are controlled by the system controller 13.

Next, the signal system will be described. The color image signal from the input terminal 1 is supplied to the RGB encoder 2 to be converted into red, green and blue signals R, G and B, and then supplied to the A / D converter 3 to be converted into an 8-bit digital signal, for example. After the conversion, it is supplied to and stored in the field memory 4. Digital red read from the field memory 4,
The green and blue signals are supplied to the selector 5 and selected.
The selector 5 can switch between the field mode and the frame mode, and in the frame mode, the frame signal is obtained by the interpolation processing of the field signal of each color.

Digital field (or frame) signals of red, green and blue signals from the selector 5 are individually supplied to a table ROM 6 for brightness control, and as shown in FIG.
The brightness of the green signal G supplied to the RT8 is the red and blue signals R and B.
Brightness (the brightness of the red signal R is higher than that of the blue signal B) and the brightness of the red, green and blue colors of the color instant film 12 with respect to the brightness levels of the red, green and blue signals R, G and B. The red, green, and blue signals R, G, and B are γ-corrected so that the characteristics of are substantially linear, and then supplied to the D / A converter 7 to be converted into an analog signal and supplied to the black and white CRT 8. To do. Further, according to the conversion of the brightness levels of the red, green and blue signals R, G and B by the ROM 6, the exposure time of the red, green and blue image light to the instant film 12 (of the shutter 11 so that a good color image can be obtained). Set the opening time).

The writing and reading of the field memory 4 and the timing thereof are controlled by the system controller 13. The selection of the selector 5 and the switching between the field mode and the frame mode are controlled by the system controller 13.

According to the above-described embodiment, the brightness of the green signal G supplied to the CRT 8 is made lower than the brightness of the red and blue signals R and B by the brightness control table ROM 6 and the shutter 11, and a good color image is obtained accordingly. Instant film of red, green and blue image light to get
The exposure time (opening time of the shutter 11) for 2 is set respectively, and the characteristics of the brightness of the red, green and blue colors of the color instant film 12 with respect to the brightness levels of the red, green and blue signals R, G and B are set. The red, green and blue signals R, G and B are respectively set to γ so that they become substantially straight lines.
Since the correction is performed, the resolution of the color image formed by printing the instant film 12 can be increased and the blue signals R and B can be increased even if the luminance levels of the red and blue signals R and B supplied to the CRT 8 are high. Since the exposure time can be shortened, the time required for printing can be shortened. When the time required for the conventional printing described at the beginning is 12 seconds (8 seconds for red, 2 seconds for blue, and 2 seconds for green), the time required for printing is 5 seconds (3 seconds for red, 3 seconds for red,
It was 1 second for blue and 1 second for green).

In the above embodiment, the γ correction characteristics for the red, green and blue signals may be set so that the exposure times of the red, green and blue image lights on the instant film 12 are equal. . In this case, since the opening times of the shutter 11 for the red, green and blue image lights become equal, the shutter 11 can be easily controlled.

[0014]

According to the present invention described above, it is possible to obtain a CRT printer capable of printing a high-resolution color image even if the time required for printing is short.

[Brief description of drawings]

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

FIG. 2 is a characteristic curve diagram showing input / output luminance characteristics of the example.

FIG. 3 is a characteristic curve diagram showing a conventional input / output luminance characteristic.

[Explanation of symbols]

 1 Color image signal input terminal 2 RGB encoder 3 A / D converter 4 Field memory 5 Selector 6 Luminance control table ROM 7 D / A converter 8 Monochrome CRT 9 Color filter 10 Optical system 11 Shutter 12 Instant film 13 System control apparatus

Claims (4)

[Claims] 1. A black and white CRT to which red, green and blue signals of a color image signal are respectively supplied, and optics arranged on the tube surface side of the CRT which can be switched to a red, green and blue filter accordingly. A CRT printer having a filter, wherein red, green, and blue image lights respectively obtained from the optical filter are separately overlapped and exposed on an instant film through a shutter and an optical system, and are supplied to the CRT. The brightness of the green signal is made lower than the brightness of the red and blue signals, and the exposure times of the red, green and blue image lights to the instant film are set so that a good color image can be obtained accordingly. CRT printer. 2. The red, green and blue signals are respectively set to γ so that the characteristics of the brightness of the red, green and blue colors of the instant film with respect to the luminance levels of the red, green and blue signals are substantially linear. 2. The CRT printer according to claim 1, further comprising a [gamma] correcting means for correcting. 3. The CRT printer according to claim 2, wherein a table ROM is used as the γ correction means. 4. The gamma correction characteristic for each of the red, green and blue signals is set so that the exposure times of the red, green and blue image lights on the instant film become equal. The CRT printer according to 2 or 3.