JPS619075A - Color reader having black and white mode - Google Patents

Abstract

PURPOSE:To execute the reading at white/black mode at a high speed than that at color mode by providing a lighting control means lighting sequentially while switching three fluorescent lights at the color mode selection and lighting simultaneously the fluorescent lights at white/black mode selection. CONSTITUTION:Figure shows the time chart at color mode selection. An electric charge at photodetecting section is transferred in parallel with each bit of an analog shift register by using a transfer pulse PHIT to a CCD and a CCD output signal is read via an amplifier circuit 8. A red lighting signal TR, a green lighting signal TG and a blue lighting signal TB are outputted sequentially from the control circuit in synchronizing with the transfer pulse PHIT and the red/green/ blue three fluorescent lights 2-4 are lighted sequentially according to the said output. On the other hand, the lighting signals TR, TG, TB are outputted simultaneously to the three fluorescent lights 2-4 at white/black mode selection, they are lighted simultaneously and the simultaneous lighting is executed at each period of the transfer pulse PHIT. Thus, the time width of the lighting signal is decreased to 1/3 at the color mode.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to an apparatus for reading document information, and more particularly to a reading apparatus that has two modes: color reading that separates the information into color signals, and black and white reading that does not separate the information into color signals.

<Prior art> Conventionally, in a color reading device such as a drum scanner, color reading is performed by providing red, green, and blue filters and three photoelectric conversion elements that receive the transmitted light of each filter. The fourth part receives the transmitted light.
Many devices are equipped with photoelectric conversion elements to perform black-and-white and halftone reading.

However, in this conventional example, not only is it extremely difficult to relatively align the three color photoelectric conversion elements, but also another set of filters and photoelectric conversion elements are required for the monochrome mode. There were drawbacks that I had to prepare for.

<Objective of the Invention> An object of the present invention is to enable both color reading and black-and-white reading modes to be performed using a single photoelectric conversion element, and to perform reading in the black-and-white mode faster than in the color mode. An object of the present invention is to provide a color reading device having a black and white mode.

<Solution Means> In order to achieve the above object, the present invention provides three fluorescent lamps each having a peak value in the red, green, and blue wavelength bands for illuminating the original to be read, and a real image i of the original. a single photoelectric conversion element disposed at the real image position; a mode selection means for selecting a color mode or a black and white mode; and when the color mode is selected, the three fluorescent lamps are sequentially switched to emit light. , when the above black and white mode is selected, the above 3
It is characterized by having a light emission control means for causing all the fluorescent lamps to emit light at the same time.

<Example> FIG. 1 shows an overall configuration diagram of the present invention. Three fluorescent lights 2, 3, red, edge, and blue, for illuminating the document 1 to be read.
4 is disposed, and a COD and a sensor 7 are disposed on the image forming surface of the original by an optical system consisting of a mirror 5 and a convex lens 6. The output signal of the CCD sensor 7 is
The signal is amplified by the amplifier circuit 8 and introduced into the 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.

The lighting circuit 10 causes each fluorescent lamp to emit pulsed light. A mode selection button 11 is connected to the control circuit 9.

Next, the action will be explained.

FIG. 2 shows a time chart when selecting the color mode.

The charge in the light receiving section is transferred in parallel to each bit of the analog shift register by the transfer pulse Φ to the COD, and then serially led out by the shift register, and the CCD output signal is read out via the amplifier circuit 8. This transfer pulse Φ
In synchronization with T, a red lighting signal TR1, a green lighting signal TQ, and a blue lighting signal TB are sequentially output from the control circuit, and the three red, green, and blue fluorescent lamps 2.3.4 sequentially emit light accordingly. do. Each time width of the lighting signals TN, Tq, and T is determined in advance according to the luminous intensity of each fluorescent lamp.

Due to this sequential switching of light emission, the COD changes to red, green, blue, for each period separated by the transfer pulse Φτ.
Outputs glossy separated color signals.

FIG. 3 shows a time chart when black and white mode is selected. This mode differs from the color mode described above in 3 ways.
The lighting signal Tlt,' for the fluorescent lamps 2.3.4
rq, 'rB are output all at once and emit light at the same time, the simultaneous light emission is executed during all periods of each transfer pulse Φ1, and the time width of the lighting signal is different from that in the color mode described above. It is now 1/3 shorter. As a result, the scanning speed of the original is three times faster than when the color mode is selected, and since the size of the CCD output is the same as when the color mode is selected, the CCD output signal can be processed in common. .

<Effects of the Invention> As described above, according to the present invention, both color reading and black-and-white reading can be performed by using a single COD, and since a single COD is used, the COD reading can be performed easily. There is no need for alignment, and there is no need to provide special parts for monochrome mode, simplifying both the configuration and manufacturing process. Furthermore, the scanning speed when the monochrome mode is selected is three times faster than when the color mode is selected, and since the CCD outputs are the same, the signal processing circuit can be shared.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of an embodiment of the present invention, FIG. 2 is an explanatory diagram of the operation when the color mode is selected, and FIG. 3 is an explanatory diagram of the operation when the monochrome mode is selected.

Claims (2)

[Claims] (1) Three fluorescent lamps with peak values in the red, green, and blue wavelength bands for illuminating the original to be read, an optical system for obtaining a real image of the original, and an optical system installed at the position of the real image. A single photoelectric conversion element, a mode selection means for selecting a color mode or a black and white mode, and when the color mode is selected, the three fluorescent lamps are sequentially switched to emit light, and when the black and white mode is selected, the three fluorescent lamps are turned off. A color reading device with a monochrome mode and a light emission control means that causes light to emit light all at once. (2) The color reading device according to claim 1, wherein the time width of the drive signal for the fluorescent lamp when the monochrome mode is selected is 1/3 that of the color mode.