JPS6336191B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention particularly relates to a simple color facsimile transmission system with an improved scanning system.

As is well known, a color facsimile transmitter has a means for scanning an original as in a normal facsimile machine, and also transmits the scanned signal in three colors.
A means is required to divide the signal into primary colors (red, blue, green) and transmit these signals through a transmission path by time division, frequency division, or the like. FIG. 1 shows this conventional color facsimile device, in which 1 is a document drum, 2 is a synchronous motor, 3 is a lens, 4 is a red filter, 5 is a green filter, 6 is a blue filter, and 7
1 is a photoelectric conversion element, 8 is a switching device, 9 is a half mirror, 10 is a light source, 11 is a line, and 12 is a modulation/demodulation device.

In the operation of this conventional apparatus, first, the original drum 1 is rotated by the synchronous motor 2, and the original wound on the original drum 1 is illuminated by the light source 10. Then, the reflected light is divided into three by a half mirror 9, and each of the divided lights is passed through a red filter 4, a green filter 5, and a blue filter 6, whereby the optical signal on the original is separated into three primary colors. Further, the photoelectric conversion elements 7 provided in each of these are converted into electrical signals according to the respective color signals. Further, these signals are switched by a switching device 8 for parallel to serial conversion, and then sent to a modem device 12.
The signal is modulated by the signal and sent to the line 11.

The conventional device configured as described above has disadvantages in that the number of photoelectric conversion elements is increased and the sensitivity is reduced due to the use of a half mirror.

On the other hand, a conventional example as shown in FIG. 2 is also known as a simplified system of the above-mentioned conventional device. That is, in FIG. 2, 1 is the original drum, 2
is a synchronous motor, 3 is a lens, 7 is a photoelectric conversion element,
8 is a switching device, 11 is a line, 12 is a modem device, 13 is a red light source, 14 is a green light source, 15 is a blue light source, and 16 is a power source for the light source.

The operation of this conventional example is to first transfer the document to the document drum 1.
The synchronous motor 2 gives a constant rotation. The document is then illuminated by three light sources 13, 14, and 15 of the three primary colors of light, and the reflected light is focused by the lens 3, and the photoelectric conversion element 7 converts it into an electrical signal according to the intensity of the reflected light. Convert. In this case, the three light sources 13, 14, and 15 of the three primary colors of light are sequentially connected to the power source 16 by the switching device 8 every time the document cylinder 1 rotates for a certain period of time. The lights are scanned so that they are turned on in sequence. As a result, the color signals on the original are sequentially input to the modem 12 and the line 11
sent to.

The conventional system configured as described above has a simpler configuration than the conventional device described above, but for example, there are LEDs known as solid-state light sources that emit red or green light, but no one that emits blue light has been found. However, it was difficult to create a light source of three primary colors.

The present invention provides a color facsimile transmission system in which color signals are obtained using two primary color lights in order to eliminate the drawbacks of the conventional example. Hereinafter, embodiments will be described in detail with reference to the drawings.

FIG. 3 shows an embodiment of the present invention.
is the document drum, 2 is the synchronous motor, 3 is the lens, 7
is a photoelectric conversion element, 8 is a switching device, 11 is a line,
12 is a modulation/demodulation device, 13 is a red light source, 14 is a green light source, 16 is a power source for the light source, and 17 is a white light source.

Next, the operation of this embodiment will be explained. First, a document is wound around a document drum 1 and a synchronous motor 2 rotates the document at a constant speed. Then, this document is illuminated with two types of light sources 13 and 14 among the three light sources of the three primary colors of light and a white light source 17, and the reflected light is converted into an electrical signal according to the intensity. In this case, document drum 1
The light sources 13, 14, and 17 are sequentially connected to the power source 16 by the switching device 8 every rotation, and scanning is performed so that the red light source 13, the green light source 14, and the white light source 17 are sequentially turned on. At this time, the remaining signal when the electric signal obtained during the period when the red light source 13 and green light source 14 are turned on is subtracted from the electric signal obtained during the period when the white light source is turned on. It is equivalent to the electrical signal obtained by
At this time, the positions scanned during the lighting period of the red light source 13, green light source 14, and white light source 17 must of course be the same, so in this embodiment, so-called sub-scanning in the facsimile is stopped until the document drum rotates three times. There is a need. However, if the sub-scanning speed is sufficiently slower than the main scanning speed, the sub-scanning may be performed in a normal manner. In addition, in this embodiment, the red light source 1
3. Using green light source 14 and white light source 17, 3.
It has been shown that it is possible to obtain an electrical signal with characteristics equivalent to those illuminated by another primary color, blue light source, but the electrical signal obtained by this method is transmitted in the same manner as the second conventional example. be able to.

Another transmission method is to frequency-divide or divide the electrical signals obtained by lighting the red light source 13, the electrical signals obtained by lighting the green light source 14, and the electrical signals obtained by lighting the white light source 17, respectively. Of course, it is also possible to obtain the blue information by transmitting it to the receiver using a time division method and performing the above-mentioned calculations within the receiver. Furthermore, although this example shows red and green as two of the three primary colors of light, this example can also be realized using other combinations, such as red and blue, blue and green light sources, and a white light source. can do. In addition, in this embodiment, the lighting period of each light source is set to 1 on the document drum 1.
Although the example is shown in which the switching is performed every rotation, this period is not limited to this. In addition, in the above embodiment, the main scanning part is explained as follows for convenience of explanation.
We have explained the so-called cylindrical scanning method using the document drum 1 and the synchronous motor 2, but the CCD sensor
Of course, the present invention can also be applied to a so-called solid-state scanning system that uses a photoelectric scanning element such as a MOS image sensor.

Note that in an actual device, a circuit for creating other primary colors from the two primary colors is required using an analog delay circuit as shown in FIG. That is, FIG. 4 shows another embodiment of the present invention, and the same reference numerals as in FIG.
8 and 19 are analog delay circuits, 20 is a subtraction circuit for subtracting electrical signals corresponding to red and blue from electrical signals corresponding to reflected light when irradiated by a white light source, 21 is an OR circuit, and 22 and 23 are It is a switching circuit and operates as follows. Switching device 8
As a result, the light sources 13, 14, and 17 are turned on in sequence, and the photoelectric conversion element 7 sequentially outputs electrical signals corresponding to each light source. These signals are input to the modulation/demodulation circuit 12 by the switching circuits 22 and 23 synchronized with the switching device 8 as follows.

First, the signal corresponding to the light source 14 is transmitted to the switching circuit 2
2 enters the delay circuit 18, while switching circuit 2
3, the signal is directly input to the modulation/demodulation circuit 12 through the OR circuit 21. Next, the signal corresponding to the light source 13 similarly enters the delay circuit 19, and at the same time is inputted directly to the modulation/demodulation circuit 12 via the OR circuit 21 by the switching circuit 23. The signal corresponding to the light source 17 is not output from the switching circuit 23, but is input to the modulation/demodulation circuit 12 after being subtracted from the signal corresponding to the light sources 13 and 14 by the subtraction circuit 20.

As explained above, according to the present invention, since a half mirror is not used, the disadvantage of low sensitivity is eliminated, and there is an advantage that color transmission can be performed without using a light source of three primary colors.

[Brief explanation of the drawing]

1 and 2 are block diagrams of a conventional color facsimile apparatus, and FIGS. 3 and 4 are block diagrams of an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Original drum, 2... Synchronous motor, 7... Photoelectric conversion element, 8... Switching device, 11... Line, 12... Modulation/demodulation device, 13... Red light source, 14... Green light source, 1
6... Power source for light source, 17... White light source.

Claims (1)

[Claims] 1. In a color facsimile transmission system in which a color original is scanned to sequentially obtain color signals separated into primary colors, two facsimile transmission systems that emit light corresponding to two of the three primary colors are provided. a primary color light source; one white light source; means for sequentially lighting up the two primary color light sources and the one white light source at regular intervals of main scanning; A single photoelectric conversion means that converts reflected light from a document into an electrical signal, and three types of electrical signals corresponding to the two primary color light sources and the white light source sequentially output from the photoelectric conversion means, respectively. parallel output means for simultaneously outputting three types of signals by holding at least two types of signals that are earlier in time for a certain period of time; A color facsimile transmission system characterized by being provided with arithmetic means for creating a signal equivalent to a signal of other primary color lights by subtraction.