JPS6313461A - Original reader - Google Patents

Abstract

PURPOSE:To improve the S/N of an image signal output by providing a first transmitting means to supply a power and a driving signal to a light source and a photoelectric transducer string and a second transmitting means to transmit the output signal of the photoelectric transducer string. CONSTITUTION:In a sensor unit 2, a photoelectric transducer string and a light source exist, and by the power and a driving clock supplied from a case side through a cable 8, a reading action is executed. On the other hand, the image signal output obtained by the photoelectric transducer string is outputted to a case side by an optical fiber cable 8. Thus, since a cable 7 to transmit the power and the driving signal supplied to the sensor unit and an optical fiber cable 8 to transmit the image signal output are separated, even when a high speed driving signal is supplied to the sensor unit 2, the mixing of the noise from the cable 7 to the optical fiber cable 8 is not executed, and a sufficient S/N can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is used in document image processing systems using workstations, digital PPC, G4 FAX, etc., and converts documents by moving a photoelectric conversion element such as a CCD. The present invention relates to a document reading device.

Conventional technology In recent years, document reading devices have been used to automatically input handwritten characters and drawings,
Research and development is actively underway for purposes such as compositing documents created with word processors and images. Particularly those that perform high-speed and high-resolution reading operations are 04FAX and digital PP.
This is essential for C, etc.

An example of a conventional document reading device will be described below with reference to the drawings.

FIG. 3 is a schematic perspective view of a conventional document reading device. Third
In the figure, 11 is a housing, 12 is a sensor unit having a photoelectric conversion element array and a light source, and 13 is a sensor unit 12.
14 is a motor that drives the sensor unit, 15 is a wire, 16 is a document R placing glass,
17 is a cable connecting the sensor unit and the housing.

The operation of the document reading device configured as above will be described below.

First, read the original so that the surface is in close contact with the original placing glass 16! At the same time as the light source is turned on at the 0th position, a drive signal is supplied to the photoelectric conversion element array, the motor 14 is activated, and the sensor unit 12 moves while being guided by the rail 13 to read the original.

The light source and photoelectric conversion element on the sensor unit 12 are supplied with power and drive signals from the outside through a cable 17, and the output of the photoelectric conversion element is outputted through the same cable 17.

Problems to be Solved by the Invention However, in the above configuration, the power to the sensor unit, the drive signal, and the output signal are transmitted through the same cable, so noise from the drive signal and power supply is mixed into the output signal. However, there is a problem in that the S/N ratio of the image signal deteriorates and the number of gradations during halftone reading cannot be increased.

In view of the above-mentioned problems, the present invention provides a document reading device configured so that a sufficient S/N ratio can be obtained in the output signal even when the photoelectric conversion element is driven particularly at high speed.

Means for Solving the Problems In order to solve the above problems, the document reading device of the present invention includes a light source, a photoelectric conversion element array, a driving means, and a power supply and a driving signal for the light source and the photoelectric conversion element array. The device includes a first transmission means for supplying the photoelectric conversion element, and a second transmission means for transmitting the signal output from the photoelectric conversion element array.

Effects of the Invention With the above-described configuration, the present invention improves the S/N ratio of the image output signal, provides rich gradation, and enables high-speed reading.

Embodiment Hereinafter, an embodiment of the document reading device of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic perspective view of a document reading device according to a first embodiment of the present invention. In this figure, 1 is a housing, 2 is a sensor unit having a photoelectric conversion element array and a light source, and 3 is a sensor. A rail that guides the unit 2, 4 a motor that drives the sensor unit 2, 5 a wire that connects the sensor unit 2 and the motor 4, 6 a document placement glass,
7 is a cable that supplies power and drive signals to the sensor unit from the housing side, and 8 is an optical fiber cable that outputs image signals from the sensor unit.

The operation of the document reading apparatus of the present invention will be described below using this figure. In FIG. 1, a sensor unit 2 is moved along a rail 3 by a motor 4 and a wire 5. The sensor unit 2 includes a photoelectric conversion element array and a light source, and performs a reading operation using power and a drive clock supplied from the housing side through a cable 8. On the other hand, the image signal output obtained by the photoelectric conversion element array is output to the housing side via the optical fiber cable 8. According to this embodiment, since the cable 7 that transmits power and drive signals supplied to the sensor unit and the optical fiber cable 8 that transmits image signal output are separated, when a high-speed drive signal is supplied to the sensor unit 2. However, there is no noise mixing from cable 7 to optical fiber cable 8, and sufficient S
/N is obtained.

FIG. 2 is a schematic perspective view of a document reading device according to a second embodiment of the present invention. In this figure, only the points different from the first embodiment will be explained. Reference numeral 9 represents a light emitting element whose amount of light emitted changes depending on the output of an image signal, and reference numeral 10 represents a light receiving element that receives light emitted from the light emitting element. According to this embodiment, there is no noise mixed into the image signal output by the sensor cable 7, and the resistance of the cable, which is a problem when moving the sensor unit, can be greatly reduced.

Effects of the Invention As described above, the present invention provides a light source, a photoelectric conversion element array, a driving means, a first transmission means for supplying power and a driving signal to the light source and the photoelectric conversion element array, and an output of the photoelectric conversion element array. By having a second transmission means for transmitting signals, it is possible to reduce noise mixed in the output signal even when using a high-speed drive signal, and significantly improve the S/N of the image signal output. can be done.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view showing a first embodiment of a document reading device of the present invention, FIG. 2 is a schematic perspective view showing a second embodiment, and FIG. 3 is a schematic perspective view of a conventional document reading device. FIG. 1... Housing, 2... Sensor unit, 7... Cable, 8... Optical fiber cable, 9... Light emitting element, 10・・・・・・
·Light receiving element.

Claims (3)

[Claims] (1) a light source that illuminates a document; a photoelectric conversion element array that photoelectrically converts an image on the document illuminated by the light source;
a driving means for moving the photoelectric conversion element array and the light source in a direction perpendicular to the photoelectric conversion element array; a first transmission means for supplying power and a drive signal to the photoelectric conversion element array and the light source; a second transmission means for outputting an image information signal from the conversion element array, the first transmission means and the second transmission means;
A document reading device characterized in that a transmission means and a transmission means are provided separately. (2) The second transmission means has a light receiving element supported on the driving side of the driving means, and a light emitting element supported on the driven side of the driving means.
The document reading device described in section 1). (3) The document reading device according to claim (1) or (2), wherein the second transmission means includes a light emitting element, a light receiving element, and an optical fiber cable.