JPS6349432B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to a facsimile device that performs transmission and recording in two colors, black and red, using thermal recording paper that changes color from white to black and then from black to red as the amount of heat applied increases. This relates to an image signal processing method applied to. [Prior Art] Fig. 1 is a timing chart of a conventional example showing the operating status of the transmitting side, in which the scanning light (b) is ), the scanning image is irradiated alternately with the green light GL and the red light RL, and the image signal (c)
As shown, once corresponding to green light GL, red light RL
Correspondingly, two scans are performed on the image sensor, and as shown in (d) the memory access situation, the image signal from the image sensor based on the green light GL from the first scan is written and transferred to the memory by WT. Store and read out the image signal from the image sensor based on the red light RL from the second scan
The contents of the memory taken out by RD are combined and sent as black image signal B by sending (e), and the image signal from the image sensor based on the red light RL from the third scan is taken out in the same way. After combining it with the contents of the memory, it is transmitted as a red image signal R. The reflectance of white, black, and red on the scanning surface corresponding to green light GL and red light RL is as shown in the table below, and each transmitted image signal B , R are determined.

[Summary of the invention]

The purpose of the present invention is to fundamentally eliminate such drawbacks of the conventional art. On the transmitting side, first, an image signal based on light of a wavelength with a low reflectance for black and red is stored in a memory, and a black image signal is stored in a memory. Next, an image signal based on light with a wavelength that has a low reflectance for black and a high reflectance for red is synthesized with the contents of the memory, and is transmitted as a red image signal, and the image signal is transmitted as a red image signal for one cycle of the main scanning cycle. The image sensor scans 2
At the same time, the transmission image signal is transmitted continuously, and on the receiving side, recording is performed using the heat amount of black coloring according to the received black image signal,
The present invention provides an extremely effective image signal processing system in which red is recorded on top of the black printed first time using the amount of heat of red color development in accordance with the next transmitted red image signal. [Example] The details of the present invention will be explained below with reference to FIG. 2 and subsequent figures showing an example. FIG. 2 is a timing chart showing the operating status of the transmitting side, in which the scanning light (b) is
At the same time as the green light GL switches to the red light RL, the image sensor is scanned twice, and the image signal (c) is generated twice in response to this, and the image signal (c) is generated twice. As shown in the access status (d) and transmission (e), the image signal (c) from the image sensor based on the green light GL from the first scan is:
As well as being stored in memory by writing WT,
The image signal (c) from the image sensor, which is sent as a black image signal B by the transmission (e) and is based on the red light RL from the next second scan, is synthesized with the memory content retrieved by the readout RD. , send(e)
The image signal R is transmitted as a red image signal R, and this is repeated in accordance with the generation of the main scanning periodic pulse (a). Therefore, the image signals B and R are transmitted continuously, and the image sensor scans only twice in one cycle, making it possible to shorten the main scanning cycle, thereby reducing the time required for scanning. The transmission speed of the image signals B and R is increased. FIG. 3 is a block diagram showing the image signal processing circuit on the transmitting side, and the output of the image sensor IS, which performs scanning based on the clock pulse CLK, is
AND gate G ₁ , memory MM and synthesis circuit SNS
green light from the first scan
The image signal from the image sensor IS based on GL is
The green gate signal GS G generated in response to the lighting of the green light source is stored in the memory MM in response to the clock pulse CLK and the control signal W/R generated at the same timing as shown in _FIG .
1 as "H" (high level) and the gate _G1 turns on, it is sent to the output OUT via the gate _G1 and OR gate _G3 , and a black image is sent to the receiving side via the transmitting circuit. It is transmitted as signal B. Next, when the red light source lights up, the red gate signal GS _R becomes "H" and the AND gate _G2 is turned on, so that the image based on the red light RL from the image sensor IS in the second scan is signal and memory read by control signal W/R
The contents of MM, that is, the image signal based on the green light GL, are synthesized by the synthesis circuit SNS according to the control signal CS, and sent to the output OUT via AND gate G ₂ and OR gate G ₃ , and the red image is generated as before. It is transmitted as signal R. On the other hand, on the receiving side, in synchronization with the transmitting side, a signal with a short pulse width that is the amount of heat for black coloring is applied to the recording head in accordance with the first black image signal B in a predetermined order. After that, in response to the received red image signal R, a signal with a long pulse width that is the amount of heat for red coloring is similarly applied, and only the necessary pixels are printed on the black top that was printed the first time. Record the red color. Note that the synthesis circuit SNS shown in FIG. 3 performs synthesis based on the logical conditions shown in the table above, and if the scanning surface is only black, the red image signal R is not sent out. Therefore, if the scanned surface is only black, only black recording will be performed on the receiving side, and if the scanned surface is red, the black recording will be updated to red recording on the receiving side. Recording is performed in the same manner as in the past by periodic scanning and high-speed transmission. In addition, in order to realize the operation shown in Figure 2 and the operation on the receiving side, it is only necessary to slightly change the conventional circuit configuration. It is sufficient to use a combination of gates. However, the AND gates G ₁ and G ₂ in Figure 3 are
It may be replaced with a NAND gate, an inhibit gate, a switch circuit, etc., and the same effect can be obtained by using a NAND gate, a mixed circuit, etc. in place of the OR gate _G3 , and various modifications are possible. Although the above embodiments have been explained using green light and red light, the present invention is not limited to these lights, and instead of green light, light with a wavelength having a small reflectance for black and red may be used, or red light may be used instead of green light. Instead of light, light having a wavelength that has a low reflectance for black and a high reflectance for red may be used. [Effects of the Invention] As is clear from the above description, according to the present invention, the number of scans of the image sensor is reduced, the time required for scanning is reduced, and the transmission image signal is transmitted continuously, which increases the transmission speed. improved,
A remarkable effect can be obtained in a facsimile apparatus that transmits and records in two colors, black and red.

[Brief explanation of the drawing]

Fig. 1 is a timing chart of a conventional example showing the operating status of the transmitting side, Fig. 2 and subsequent figures show embodiments of the present invention, Fig. 2 is a timing chart showing the operating status of the transmitting side, and Fig. 3 is a timing chart of the transmitting side. FIG. 2 is a block diagram showing an image signal processing circuit of FIG. IS...Image sensor, MM...Memory,
SNS...Synthesis circuit, _G1 , _G2 ...AND gate, _G3
………OR gate, GS _G …green gate signal,
GS _R ...Red gate signal.

Claims (1)

[Claims] 1. In a facsimile machine that transmits and records in two colors, black and red, using heat-sensitive recording paper that changes color from white to black and from black to red as the amount of heat applied increases, the transmitting side uses one rotation of the main scanning period. Scanning is performed twice in a period, and in the first scan, an image signal based on light of a wavelength with a small reflectance for black and red is stored in a memory and transmitted as a black image signal,
In the next scan, the content of the memory is combined with an image signal based on a wavelength of light that has a low reflectance for black and a high reflectance for red, and is transmitted as a red image signal, and the receiving side receives the first received signal. Recording is performed using the amount of heat that produces black color in response to the black image signal, and then, in response to the received red image signal, red is recorded on top of the black that was recorded the first time using the amount of heat that produces red color. An image signal processing method characterized by: