JPH0463060A - Image reader - Google Patents

Abstract

PURPOSE:To suppress heat generation and radio trouble as much as possible to reduce the energy consumption by driving a clock signal with a picture element as the unit out of this clock signal and a clock signal with a line as the unit, which are outputted from a clock signal generating part, only at the time of reading a document. CONSTITUTION:A clock signal generating part 1 outputs a clock signal 1' with a picture element as the unit, which brings about problems of heat generation, radio trouble, or the like at the time of signal output, and a clock signal 2' with a line as the unit whose frequency is relatively low. A gate signal 4' is inputted. The clock signal 1' with a picture element as the unit is so controlled that it is driven only at the time of reading the document.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an image reading device, and particularly to an image reading device that is most suitable for devices such as electrophotographic machines and facsimiles that use a reading element such as a CCD to read documents. It is related to.

[Conventional technology]

An image reading device generally uses an image sensor such as a CCD to read an image of a document or the like through an optical system and performs photo-electrical conversion while moving the document and the image sensor relative to each other.
The converted signal is processed and stored as image data in a storage medium, or used for image display on a display, hard copy on a printer, etc. The reading operation of the image sensor is performed by a clock signal, and in order to generate this clock signal, the CPU (
The control unit, whose control center is a central processing unit, is equipped with a clock signal generation circuit or a timing generation circuit.

However, when the conventional image reading device is turned on, the CC
D and other various circuits are always in operation and are driven even when images are not actually required to be read. The CCD in such a device spends a long time in a standby state compared to the time used for image reading operation.
There is a problem that power is wasted and the temperature inside the device increases.

In order to solve these problems, the present applicant previously proposed an invention as described in Japanese Patent Application No. 1-213082.

In other words, the present invention provides an image reading device that reads images of documents, etc. using a CCD as a reading element. The image forming apparatus includes a gate circuit that selects whether or not to supply or stop the image, and a control means that opens the gate circuit when reading an image.

[Problem to be solved by the invention]

However, since this invention requires a gate circuit, the structure is complicated and the cost is high.

The present invention eliminates these drawbacks, and provides an image reading device that has a simple configuration, can reduce costs and size, can prevent radio wave interference (EMI countermeasures), and can reduce temperature rise and power consumption. is to provide.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention includes an image reading drive section that reads an image, an analog processing section that performs analog processing on the image signal read by the image reading drive section, An image reading device comprising a digital processing section that digitally processes an output signal from the analog processing section, and a clock signal generation section that outputs a clock signal for driving the image reading drive section, the analog processing section, and the digital processing section. The apparatus is characterized in that, of the pixel-by-pixel clock signal and the line-by-line clock signal output from the clock signal generating section, the pixel-by-pixel clock signal is configured to be driven only when reading an original. It is.

[Effect]

As mentioned above, there are two types of clock signals output from the clock generator: pixel-by-pixel clock signals and line-by-line clock signals. Heat generation during output and radio interference are problems. Therefore, if this pixel-by-pixel clock signal is output only when reading the original,
Heat generation and radio wave interference are suppressed, contributing to energy conservation.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings. The drawing is a block diagram of an image reading device, in which 1 is a clock signal generator, 2 is a gate circuit, 3 is a CPU, and 4 is a CCD.
5 is an analog processing section that performs analog processing on the image data (2) outputted from the image reading drive section 4, and 6 is a digital processing section that further digitally processes the image data (2) output from the analog processing section 5. This is the processing section.

As mentioned above, the clock signal generator 1 outputs the pixel-by-pixel clock signal (■) which causes problems such as heat generation and radio wave interference when outputting the signal, and the line-by-line clock signal (■) which has a relatively low frequency. ing. Note that ■ is a gate signal.

The clock signal (2) for each pixel is controlled so as to be driven only when reading an original.

〔Effect of the invention〕

As described above, the present invention is configured such that among the clock signals output from the clock signal generating section, the clock signal for each pixel is output only when reading an original.

Therefore, heat generation and radio interference are suppressed as much as possible, and an energy-saving image reading device can be provided.

[Brief explanation of the drawing]

The drawing is a block diagram of an image reading device.

Claims (1)

[Claims] An image reading drive unit that reads an image, an analog processing unit that performs analog processing on the image signal read by the image reading drive unit, and a digital processing unit that digitally processes the output signal from the analog processing unit. a processing section; the image reading drive section;
In an image reading device comprising a clock signal generation section that outputs a clock signal for driving an analog processing section and a digital processing section, a clock signal for each pixel and a clock signal for each line output from the clock signal generation section. An image reading device characterized in that the clock signal for each pixel is configured to be driven only when reading a document.