JPS6022864A - Image reading device - Google Patents

Abstract

PURPOSE:To attain miniaturization and light weight of an image reading device by arranging the 1st mirror receiving a reflected light from an original between the 2nd mirror receiving the reflected light from the 1st mirror and a photoelectric converting element. CONSTITUTION:The image information on the original 5 is reflected on the 1st mirror 7 arranged between the photoelectric converting element 9 and the 2nd mirror 11 and on the 2nd mirror 11 arranged at the opposite side to the photoelectric converting element 9 by taking the 1st mirror as a boundary and the image is formed on the photoelectric converting element 9 through a lens 8. The 1st mirror 7, the 2nd mirror 11, the lens 8 and the photoelectric converting element 9 and a shading plate 13 are fixed to a support 12, a pin 15 is inserted to a hole 16a provided to a stay 16 to restrict the turning of the support 12. The miniaturization of the device and then the light weight of the device are attained through the arrangement.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to an image reading device, and more particularly to an image reading device with an improved configuration of a reading optical system.

Prior Art The configuration of the reading optical system of a conventional image reading device is as follows.
As shown in the figure.

In FIG. 1, reference numerals 31 to 34 indicate transport rollers that transport the original 35 along guides 45 and 46.

When the document 35 comes to the reading position, it is irradiated by a light source 36, and the reflected light is guided to a lens 38 by a mirror 37 located below.

The mirror 37 is fixed to a side plate 44 on the device main body side via a mirror stay 43, and the lens 38 is fixed to a side plate 44 on the side of the main body of the device via a mirror stay 43.
1 to the side plate 44 of the main body of the apparatus.

A shading plate 42 is fixed to the lens stay 41, and a photoelectric conversion element 39 is fixed on a support plate 40 fixed via a stud 41a.

In the structure shown below, the main body side plate 44, mirror stay 43, and lens stay 41 are directly attached to the device main body, so if their rigidity is insufficient, the distortion of the device main body due to external force will be read as is. This has the disadvantage that it appears as a defective image. In addition, when adjusting the light source system, there are many adjustment items such as reference reading position, reading start position, focus, output uniformity, slice level, etc. Furthermore, adjustment must be done within the device itself, which reduces work efficiency during adjustment. There was also a drawback.

Part II of the present invention was made in order to eliminate the above-mentioned drawbacks of the conventional art, and provides an image reading device that has a unitized image reading system with increased rigidity, is compact, and has high adjustment work efficiency. It is intended to.

EXAMPLES Hereinafter, the present invention will be explained in detail based on examples shown in the drawings.

In the figure, reference numerals 1 to 4 are document conveying rollers, reference numeral 5 is a document, and reference numeral 6 is a light source. A first mirror designated by numeral 7 that reflects the original image is located between a photoelectric conversion element designated by 9 and a second mirror designated by 11, and this arrangement is perpendicular to the main scanning direction of the entire apparatus. This contributes to reducing the dimensions in the direction of The one indicated by the symbol 8 is a wide-angle lens, the symbol 1o
The one shown is the pudding that controls the photoelectric conversion element]・
The substrate, denoted by reference numeral 12, is a support for holding the optical system;
The reference numeral 13 indicates a shading plate for making the amount of light incident on the photoelectric conversion element 9 uniform. 14 is a set screw, and 15 is a support 12.
This is a pin that restricts the rotation of the This pin is fixed to an L bracket 12b fixed to the support 12. code 16
Reference numerals 18 and 19 indicate stays fixed to the side plates 17 and 20 of the main body of the apparatus, and pins 18 and 19 rotatably support the support body 12.

Next, the operation of the embodiment of the present invention configured as described above will be explained. When the original 5 is conveyed to the image reading position by the original conveyance roller 3.4, the image information of the original 57 is transferred to the first mirror disposed between the photoelectric conversion element 9 and the second mirror 11.
The light is reflected by the mirror 7 and the second mirror 11 placed on the opposite side of the photoelectric conversion element 9 with the first mirror 7 as the boundary, and the amount of peripheral light is corrected by the shading plate 13 placed directly below the first mirror 7. , an image is formed on the photoelectric conversion element 9 through a lens 8 disposed between the photoelectric conversion element 9 and the shading plate 13. The support body 12 that holds the first mirror 7, the second mirror 11, the shading plate 13, the lens 8, and the photoelectric conversion element 9 is fixed to the side plate 20 and a pin 19 fixed to the support body 12 between the device body side plates 17 and 20. The pin 15 fixed to the support 12 fits into the hole 16a provided in the stay 16, and the support 1
The rotation of 2 is regulated.

Next, in the configuration of the optical system described above, how the size can be reduced in the direction orthogonal to the main scanning direction will be explained using an example.

When the reduction ratio is approximately 1/10, the effective reading width in the main scanning direction is 25.6 mm, the half angle of view of the wide-angle lens 8 is 25 degrees, and the total optical path length is 310 + nm, as shown in Fig. 5. The distance a between the original 5 and the first mirror 7 is 29 mm, the distance between the first mirror 7 and the second mirror 11 is 110 mm, and the distance C between the second mirror 11 and the photoelectric conversion element 9 is 171 mm. 2nd mirror 1 compared to reading width
It can be seen that the distance C between 1 and the photoelectric conversion element is small. In addition, C0 due to the use of a wide-angle lens with a half-angle of view of 25 degrees.
The shading plate 13 also reduces the amount of peripheral light due to the 84θ law.
It is possible to sufficiently correct it by arranging it directly below the first mirror 7. Note that the hole 13a of the shading plate 13 becomes smaller as the shading plate 13 approaches the lens.
(See FIG. 4) The R (radius) of the side edges that make up the lens becomes smaller and becomes larger as the distance from the lens increases. In this configuration, the shading plate 13 is arranged directly below the first mirror 7 in consideration of ease of manufacturing and assembly.

Since this embodiment is configured as follows, the length between the second mirror and the photoelectric conversion element is smaller than the width in the scanning direction (1), which includes the effective reading width, in the shape of the support 12. This has the effect of contributing to miniaturization of equipment that uses the image 1 reading device, for example, the main body of a facsimile machine.

In addition, since the image reading device is separated from the device wooden cup except for the light source and configured as a unit, distortion of the device body due to external force as in conventional image devices does not directly cause defects in the read image. This has the effect of reducing the weight of the entire device and contributing to the use of plastic. Further, because of this unitization, the adjustment of the device can be carried out completely separately from the device itself, which has the effect of greatly improving work efficiency.

As is clear from the above explanation, according to the present invention, the image reading device can be made smaller and lighter, and can be made of plastic, and the work efficiency of adjusting the device can also be improved. This effect can be obtained.゛

[Brief explanation of the drawing]

Figure 1 is a longitudinal sectional view to explain the conventional structure, Figure 2~
5 is for explaining one embodiment of the present invention, FIG. 2 is a longitudinal sectional view, FIG. 3 is a view taken along the line A-A in FIG. 2, and FIG. FIG. 5, a sectional view taken along the line B-B, is an explanatory diagram of the optical system. 7... First mirror 11... Second mirror 8... Lens 9... Photoelectric conversion element 12... Support body 15.
18.19...Pin 13...Shading plate Fig. 1 Fig. 2 Fig. 4 Fig. 3 Fig. 5

Claims (3)

[Claims] (1) A first mirror that receives the light obtained from the original, a second mirror that receives the reflected light from this first mirror, a lens that receives the reflected light from this second mirror, and a lens that receives the reflected light from the second mirror. An image reading device comprising a photoelectric conversion element on which a document image is formed, the first mirror being disposed between the second mirror and the photoelectric conversion element. (2) The image reading device according to claim 1, wherein the mirror of '51, the second mirror, the lens, and the optical 7IL conversion element are mounted on a common support. (3) The shading plate that corrects the amount of peripheral light in the read image is located directly under the second mirror and is mounted on a common support.
2. The image reading device according to claim 2, wherein the image reading device is provided at 1-.