JPH0263222B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Technical Field> The present invention relates to a device that separates document information into color signals and reads them, and is used, for example, in color facsimiles, color scanners, and the like.

<Problem to be solved> The applicant sequentially switches fluorescent lamps of the three primary colors of red, green, and blue to illuminate the document to be read, forms an image of this transmitted light or reflected light with a lens, and creates a single image on the imaging surface. We have already proposed a color reading system that uses one CCD sensor.

When this device is used for color facsimile, for example, the amount of color information in one scan changes with each scan, so the time for one scan changes, and the transmission speed changes accordingly. When used for this purpose, there is a characteristic that the time required for one scan changes depending on the receiving speed of the other machine. As described above, since the emission states of the red, green, and blue fluorescent lamps change depending on the color state of the original image, there is a risk that the accuracy of color separation may decrease.

Fluorescent lamps generally involve some delay from when a lighting signal is applied until they are fully lit. In FIG. 3, A indicates the lighting signal, and B indicates the light output of the fluorescent lamp. This delay time t becomes longer as the lighting pause time T from the previous lighting time becomes longer, and the light output becomes smaller. This is related to the temperature of the fluorescent lamp filament, gas temperature, etc. In this way, changes in pause time due to differences in documents affect the accuracy of color separation.

<Objective of the Invention> The object of the present invention is to stably obtain uniform light output by driving each fluorescent lamp to emit light after a substantially constant rest time has elapsed, regardless of the color state of the original drawing. The object of the present invention is to provide a color reading device.

<Solution Means> In order to achieve this object, the present invention is characterized by providing means for lighting all the fluorescent lamps at a predetermined time immediately before the sequential switching drive of the fluorescent lamps.

<Example> FIG. 1 shows an overall configuration diagram of the present invention. Three fluorescent lights 2, 3, and 4 of red, green, and blue are arranged to illuminate the document 1 to be read, and an optical system consisting of a mirror 5 and a convex lens 6 illuminates the image plane of the document.
A CCD sensor 7 is provided. CCD sensor 7
The output signal is amplified by an amplifier circuit 8 and introduced into a control circuit 9. The control circuit 9 outputs a lighting signal to the fluorescent lamp lighting circuit 10 at a predetermined timing synchronized with the control of the CCD sensor. lighting circuit 10
causes each fluorescent lamp to emit pulses.

The present invention is characterized by the means by which the control circuit 9 outputs the lighting signal. This characteristic part will be explained together with the operation of the present invention.

FIG. 2 is a time chart showing the operation of the embodiment of the present invention. The charges in the light receiving section are transferred in parallel to each bit of the analog shift register by the transfer pulse Φ _T to the CCD, and then serially led out by the shift register, and the CCD output signal is read out via the amplifier circuit 8. In synchronization with this transfer pulse Φ _T , the control circuit outputs a red lighting signal T _R , a green lighting signal T _G , and a blue lighting signal T _B , and accordingly each of the red, green, and blue fluorescent lights 2, 3, and 4 emit light.
Normally, light emission is controlled by switching sequentially, for example, in the order of red, green, and blue. Emission pause time T due to page turning of the original, etc.
At a predetermined time K, such as when the time lengthens, all the lighting signals T _R , T _G , and T _B are output simultaneously, and all the fluorescent lamps emit light at the same time. The charge generated in the CCD at this time is transferred to the shift register by the next transfer pulse, and a large CCD output k' is obtained, but this output signal k' is not used for data processing. Continuing,
The lighting signals T _R , T _G , and T _B are outputted in the above-described predetermined order and color separation is performed. Since the lighting of the fluorescent lamps immediately after simultaneous lighting is very short, the delay time t shown in FIG. 3 is small and no decrease in light emission output is observed.

The predetermined time k for outputting the lighting signals all at once may be set immediately before each lighting for document irradiation,
Alternatively, the downtime may be compared with a preset time and set only when the set time is exceeded.

<Effects of the Invention> According to the present invention, even when the light emission is stopped for a long time, the light emission for reading the document is performed after all the fluorescent lamps emit light at the same time, so that the lighting delay time of the fluorescent lamps can be kept within a certain range. It is possible to perform color separation with high accuracy.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram of an embodiment of the present invention, FIG. 2 is an explanatory diagram of the operation of the embodiment, and FIG. 3 is an explanatory diagram of the problem to be solved. 1... Manuscript, 2, 3, 4... Fluorescent light, 7...
CCD sensor, 9... control circuit, 10... lighting circuit.

Claims (1)

[Claims] 1 Using a plurality of fluorescent lamps with mutually different wavelength characteristics for illuminating the original to be read and a single sensor arranged on the imaging plane of the original, the fluorescent lamps are sequentially switched and driven. 1. A color reading device for color-separating a document, characterized in that the color reading device is provided with means for turning on all the fluorescent lamps at a predetermined time immediately before the sequential switching drive of the fluorescent lamps.