JPS6034313B2 - CRT hard copy device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a CRT hard copy device used in computer output printing devices, display printers, etc., and more particularly to a device for obtaining hard copies from television signals.

When an input television signal is displayed in brightness on a CRT (cathode ray tube) and a hard copy of this displayed image is obtained by electrophotography, as the size of the hard copy increases, the number of scanning lines of the television signal increases. becomes a problem.

For example, in the Nippon Television standard system, the number of effective screen scanning lines is 483, so the hard copy size is A4.
(210 x 299 fences), the number of scanning lines is about 2.7, which makes the scanning lines noticeable and degrades the quality of the hard copy. An object of the present invention is to provide a CRT hard copy device that is improved so that the scanning lines are not noticeable when the input television signal is made into a hard copy when the number of scanning lines is small compared to the hard copy size. It's about doing.

When an image displayed in brightness on a CRT is image-formed and exposed on an electrophotographic photoreceptor using an optical system to obtain a static exposure latent image corresponding to the image displayed on the CRT, the electron beam of the CRT is directed perpendicular to the scanning direction of the scanning line. If the scanning line is periodically reciprocated by an amount that does not exceed the neighboring scanning line in the direction of , the scanning line will no longer be noticeable.

A commonly used method for this method employs a spot-to-obbling method in which the electron beam is varied at a relatively high frequency as a reimaging technique. For example, a frequency of 29 MHZ is used as a spot-to-ring frequency in a television standard format conversion device for converting from a 525-line 3-line system to a 625-line 29-line system. In order to deflect the electron beam at such a high frequency, it has been usual to use a deflection coil for spot wobbling in addition to that for line scanning and field scanning. If such a method is adopted, not only a deflection coil for spot wobbling but also a 29 MHz oscillator will be required, which will complicate the circuit configuration and cause an increase in cost. However, the image displayed on the CRT brightness is imaged and exposed on an electrophotographic photoreceptor using an optical system, and CRT
When obtaining a static latent image corresponding to the displayed image on RT, 0.
Since an exposure time of 1 second or more is usually required, 1 to 2 seconds is required.
Instead of the above-mentioned spot wobbling method, there is a spot wobbling method in which the displayed image on the CRT is slowly moved back and forth in a direction perpendicular to the scanning direction of the scanning line, in other words, the line shift method makes the scanning line less noticeable on hard copies. The same effect as the bling method can be obtained.

If the line shift method is adopted, this can be achieved simply by superimposing a signal with an amplitude corresponding to the amount of line shift on the field scanning signal applied to the deflection coil that deflects the electron beam in a direction perpendicular to the scanning direction of the scanning line. There is no need for something similar to a deflection coil for spot-to-object rings. Also,
Since this line shift signal can be generated from the field scanning signal, a hard copy with inconspicuous scanning lines can be obtained without complicating the circuit configuration.
The present invention will be explained in detail below with reference to the drawings.

Figure 1 shows the Walcup method (US Patent No. 28) as an electrophotographic method.
25814, 1958), and FIGS. 2 and 3 show system diagrams of a CRT hard copy apparatus according to the present invention.
In FIG. 1, a television signal applied to an input terminal 1 is sent to a process amplifier 2 and a sync separation circuit 4. The process amplifier 2 performs video processing necessary to obtain the optimum image for a CRT hard copy device, such as automatic gain control, DC reproduction, aperture compensation, etc., and sends it to the video amplifier 3, where it is amplified to the optimum level for the CRT 12. do. On the other hand, the synchronization separation circuit 4 separates the line scanning pulse 7 and the field scanning pulse 6 from the input television signal and sends them to the deflection amplifier 5, and the line scanning signal 9 is sent to the line scanning deflection coil 11 for field scanning. The signal 8 is applied to a field scanning deflection coil 10', and a two-dimensional image of the input television signal is transmitted to the phosphor screen 13 of the CRT 12.
to be displayed. This display image is focused on the photoconductive layer 16 of the electrophotographic photoreceptor 15 by the optical system 14, and a voltage of several hundred volts is applied between the photoreceptor 15 and the back electrode 19, thereby changing the display image on the CRT. A corresponding static latent image is formed on the recording paper 18. Then, feed the recording paper to the left in the figure, cut it to the appropriate paper size using the cutter 20', and then use the developing machine 20'.
At step 1, the static exposure latent image is visualized, and at fixing section 22, the image is fixed on recording paper, and the completed hard copy is sent out in the direction of arrow 23. 17 is a roll recording paper.

In such a state, the television image on the fluorescent screen 13 of the CRT 12 is directly formed on the recording paper, so as the recording size becomes larger, the scanning lines of the television image become more noticeable. Approximately 2 for A4 size standard television image
．． 7 lines/sail scanning line, which is a sight to behold. According to the embodiment of the invention of FIGS. 2 and 3, the above-mentioned drawbacks can be eliminated relatively easily and hard copies with less noticeable scan lines can be obtained.

In FIG. 2, the explanation up to the arrow 23 indicating the direction in which the recording paper is sent out from the input terminal 1, which overlaps with that in FIG. 1, will be omitted. The frame pulse is separated by the synchronization separation circuit 4 shown in FIG. 2, and the frequency is divided by an integer by the counter 24. Take out the output from the flip-flops in each stage of the counter 24,
A staircase wave signal is formed in the matrix circuit 25. By adjusting the amplitude with the adjuster 26 and superimposing it on the field scanning signal 8, the displayed image on the phosphor screen 13 is shifted in the field scanning direction frame by frame. This amount of deviation can be changed by the adjuster 26, and between the two images that are most often shifted in opposite directions, the scanning line of a certain image does not overlap with the scanning line next to the other image, and Adjust the adjuster 26 so that it does not occur. In this way, assuming that the exposure time is sufficiently longer than the frame period, the number of scanning lines when a hard copy is made will appear to be the reciprocal of the frequency division ratio determined by the counter 24. That is, if the counter 24 is a 1/2 frequency divider consisting of one stage of flip-flops and the matrix circuit 25 passes through, the amount of image shift is set to 1/2 between adjacent scanning lines. This makes the image apparently equivalent to twice as many scanning lines.
For standard television format, the recording size of A4 is approximately 5.4
As a result, you can obtain a hard copy with almost no noticeable scan lines. When the frequency division ratio of the counter 24 is set to 1/integer (3 or more), each level of the staircase wave signal output from the matrix circuit 25 is made to be different within one cycle of the staircase wave signal. However, it is desirable that the intervals between each level be equal when considering one entire cycle of the staircase wave signal. For example, the simplest and most appropriate method is to use a staircase wave that monotonically increases or decreases step by step, with the steps being equal for each step. Next, the embodiment shown in FIG. 3 will be described. In FIG. 3, parts that are repeated from FIG. 1 are omitted.

In FIG. 3, an oscillator 27 is provided which is independent of the input television signal, and the output signal of this oscillator 27 is sent to a regulator 28.
By superimposing the field scanning signal 8 on the field scanning signal 8 via the phosphor screen 13, the displayed image on the phosphor screen 13 can be shifted in the field scanning direction. The regulator 28 is the regulator 26 in FIG.
Similarly, when shifting, adjust so that it does not exceed the adjacent scanning line. In FIG. 3, since the oscillator 27 is independent of the input television signal, it is preferable that the signal superimposed on the field scanning signal 8 be a sine wave. The reason for this is that the input television signal and the signal from the oscillator 27 are constantly fluctuating in phase because they are independent oscillators. This state is called normal flow. Therefore, if a sine wave is used, the displayed image will gradually shift, so the front non-rainy image will be shifted continuously instead of discontinuously as in the embodiment shown in FIG.
Ideally it would be possible to obtain a hard copy without scanning lines. For example, if the current input is a standard television signal and the oscillation frequency of the oscillator 27 is 50Hz, the displayed image will be 3
It returns to its original position at frame number. Therefore 3
This is equivalent to an image with twice as many scanning lines. If the exposure time is longer than 1 second, the oscillation frequency of the oscillator 27 may be set to a value slightly different from the frame frequency of the input television signal, such as 29Hz or 31Hz, so that the displayed image can be adjusted to 3
It returns to its original position in the 07th frame. That is 3
It becomes equivalent to the image of the scan line of the sound, and the scan line can no longer be found on the hard copy. As described above, according to the present invention, a CRT capable of producing hard copies with inconspicuous scanning lines can be realized using a very simple circuit and without requiring any additional special parts such as deflection coils for spot warping. Hard copy equipment can be provided.

Although the above explanation has been given only to the Walcup method as an electrophotographic method, it is clear that it is not limited to the Walcup method and can be applied to any electrophotographic method that performs long exposure (approximately 0.1 seconds or more). .

Furthermore, it is clear that the present invention is not limited to CRTs that display plane images, but can also be applied to CRTs that display -dimensional images such as OFT (optical fiber tube).

[Brief explanation of the drawing]

Figure 1 is a system diagram of a conventional CRT hard copy device;
The figure is a system diagram showing one embodiment of the present invention, and FIG. 3 is a partial system diagram of another embodiment of the invention. In the figure, 1: input terminal, 2: process amplifier,
3: Video amplifier, 4: Sync separation circuit, 5: Deflection amplifier, 6: Field scan pulse, 7: Line scan pulse,
8: Field scanning signal, 9: Line scanning signal, 10:
Deflection coil for field scanning, 11: Deflection coil for line scanning, 12: CRT, 13: Fluorescent screen of CRT, 14:
Optical system, 15: Electrophotographic photoreceptor, 16: Photoconductive layer, 17
: Roll recording paper, 18: Recording paper, 19: Back electrode, 20
: cutter, 21: developer, 22: fixing section, 23: hard copy sending direction, 24: counter, 25: matrix circuit, 26, 28: level adjuster, 27: oscillator. 1 corner' figure Hiiragi Z figure Buchi 3 figure

Claims (1)

[Scope of Claims] 1 A television signal is displayed in brightness on a CRT, and this displayed image is imaged and exposed on an electrophotographic photoreceptor using an optical system to obtain an electrostatic latent image corresponding to the displayed image, and this In a CRT hard copy device in which an electrostatic latent image is visualized using a developer to obtain a hard copy, a first deflecting means deflects an electron beam of the CRT in a predetermined direction; a second deflection means for deflecting an electron beam of a CRT using a deflection signal having a frequency lower than the first deflection frequency; A CRT hard copy device characterized in that a shift signal for shifting the electron beam is superimposed thereon. 2. The signal superimposed on the deflection signal applied to the second deflection means is a staircase wave signal that changes every cycle of the deflection signal applied to the second deflection means, and one cycle of the staircase wave signal is different from the second deflection signal. 2. The CRT hard copy device according to claim 1, wherein each level of the staircase wave signal is an integral multiple of the period of the deflection signal applied to the deflection means and is different within one period. 3. C according to claim 1, wherein the signal superimposed on the deflection signal applied to the second deflection means is an output signal of an oscillator independent of the deflection signal applied to the second deflection means.
RT hardcopy device.