JPH01241973A - Linear image sensor - Google Patents

Abstract

PURPOSE:To attain ease of adjustment and forming inexpensively and to attain high device with optical utilization efficiency by arranging an optical sensor sensing a reflected light on an original on an image forming focus line in parallel with an image forming focus line of a light beam sweep mechanism. CONSTITUTION:A light beam 8 radiated from a laser diode 1 enters a condenser lens 11, where it is converged and the light is swept as AA' linearly on an original 5 by a sweeping polygon mirror 2 and an image forming lens 12. Then the reflected light in response to the contrast of a character/drawing of each dot on the original 5 to be swept is caused in this case. The reflected light is detected by a photosensor 4, then the linear image in the original 5 is resolved into dots and the contrast is read electrically. Thus, the cost is reduced, the adjustment is made easy and the optical utilizing efficiency is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a linear image sensor device used for reading documents such as facsimiles.

[Conventional technology]

Conventionally, this type of linear image sensor device uses a CCD as an optical sensor. FIG. 2 shows a linear image sensor device using a CCD. A one-dimensional image of a document 24 sent by a feed roller 25 is illuminated by a fluorescent lamp 23 and passed through a reduction imaging lens 22 to a CCD 2.
1, which is converted into an electrical signal and read by a CCD.

[Problem to be solved by the invention]

This kind of linear image sensor device is used for facsimiles and
It is widely used in CR1 copying machines, personal computer image input devices, etc. However, the CCD linear image sensor device has the following problems. Firstly, CCD
is expensive.

The CCD is a large-scale analogue IC obtained using high-density IC technology, and is expensive in terms of cost. In addition, the accuracy increases significantly as the number of pits increases. Second, 8 pieces/m
Adjustment of the lens part that reduces and forms a high-precision image of 16 lines/mm requires a high degree of skill, which affects the yield and cost of the device. Thirdly, of the amount of light reflected from the original, the amount of light that enters the lens is extremely small.
Light usage efficiency is poor. Fourthly, fluorescent lighting lamps have a limited lifespan, and replacement and maintenance is unavoidable.

An object of the present invention is to overcome the above problems and provide a linear image sensor device that is inexpensive, easy to adjust and manufacture, and has high light utilization efficiency.

[Means to solve the problem]

The linear image sensor device of the present invention includes a laser diode, a light beam sweeping mechanism including a polygon mirror that reflects the light beam from the laser diode, and a lens for converging and imaging the light beam without distortion; The image forming apparatus includes an optical sensor arranged parallel to the imaging focal line so as to detect light reflected from the original on the imaging focal line.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a conceptual diagram showing an embodiment of the present invention, FIG. 1(a) is a perspective view, and FIG. 1(b) is a view when viewed from the right side. A light beam 8 emitted from a laser diode 1 is focused by a focusing lens 11, and swept one-dimensionally over the original 5 by a sweeping polygon mirror 2 and an imaging lens 12 in the shape of AA'. At this time, each dot on the swept document 5 sequentially generates reflected light corresponding to the shade of the characters and figures on that dot. When the reflected light is detected by the optical sensor 4, the one-dimensional image on the original 5 can be broken down into dots and the density can be electrically read, thereby forming a linear image sensor device. 6 is a feed roller that feeds the original. The light beam sweeping mechanism is the same as that of a conventionally widely used laser beam printer, and the present invention can be easily achieved by adding a single optical sensor component to it. As the optical sensor, inexpensive components such as amorphous silicon and chalcogenide sintered bodies (CdS, etc.) can be widely used.

〔Effect of the invention〕

The present invention has the following advantages over the conventional example. First, unlike IC components such as CCDs, the laser diode and optical sensor used in the present invention are individual electrical components, so their cost is approximately 1/10 to 1/100 of that of a CCD.
And it is cheap. In addition, polygon mirrors can be obtained at low cost through mechanical processing, and lenses are also very inexpensive due to their small beam diameters. In addition, the laser beam can be imaged on the document as a minute spot of 10-odd micrometers or less, and the number of spots from 8 to 1
Since it is possible to set up to a high-definition type of 6 lines/mm or more by simple electrical adjustment of timing, etc., even if the reading density increases and the number of bits increases, the cost will hardly increase.

In addition, the present invention does not require lighting such as fluorescent lamps, reducing costs.
It is advantageous in terms of maintenance.

The second laser beam originally has a minute diameter of 1 mm or less, and its focusing and imaging are quite easy compared to forming a large image in the case of a CCD type. Thirdly, the reflected light from the original is diffusely reflected in all directions, but in the present invention, the optical sensor can be set close to the reflective surface, so the proportion of reflected light that enters the optical sensor is reduced to a distant lens like a CCD type. It is extremely large compared to the proportion that enters. If the same optical sensor 4' is added parallel to the optical sensor 4 as shown by the dotted line in FIG. 1(b) and operated in parallel, the sensitivity will be doubled. This indicates that the present invention has significantly higher light utilization efficiency than the CCD type, has higher sensitivity, or can configure the reading function with lower power. Fourthly, as a secondary but very significant effect and usefulness of the present invention, the present image sensor device can be used as a laser beam printer as it is by replacing the document paper portion with a photosensitive drum. In other words, this image sensor device can be used as a device for both recording and reading purposes. Having the same recording and reading mechanism in applications such as facsimiles and copying machines means that the cost will be halved and the size of the device will be reduced by half compared to conventional systems, making it practical. It is extremely useful.

[Brief explanation of the drawing]

FIG. 1(a) is a conceptual diagram showing an embodiment of the present invention, FIG. 1(b) is a view of FIG. 1(a) seen from the right, and FIG. 2 is a conventional CCD type linear image sensor. FIG. 2 is a conceptual diagram of the device. 1...Racer diode, 2...Polygon mirror, 4...
Light 6-sensor, 5, 24... original, 6.25... feed roller, 8... light beam, 11... condensing lens, 12...
...Imaging lens, 21...CCD, 22...Lens, 23...Fluorescent lamp.

Claims (1)

[Claims] a light beam sweeping mechanism consisting of a laser diode, a polygon mirror that reflects the light beam from the laser diode, and a lens for converging and imaging the light beam; and an imaging focal point parallel to the imaging focal line of the light beam sweeping mechanism. 1. A linear image sensor device comprising: an optical sensor arranged to detect light reflected from a document on a line.