JP2002354197A - Contact image sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a contact image sensor that can adjust its position with respect to a contact glass plate without modifying a sensor main body. SOLUTION: The contact image sensor main body 2 having a line sensor 5 applying photoelectric conversion to an original image, a light source 3 lighting an original, and a lens array 4 that forms a lighted original image on the line sensor, is supported by a sensor support member 9 whose cross section is L-shaped, an elastic member 7 that energizes the sensor support member and a base closely when the sensor support member and the base are parted is interposed between the sensor support member and the base 8 fixed to the image reader main body to support them, and a sensor position adjustment means 6 is placed to adjust an interval between the sensor support member and the base against an energizing force of the elastic member exerted to the sensor support member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact type image sensor used in an image reading apparatus, and more particularly, to a device for adjusting a position of a contact type image sensor.

[0002]

2. Description of the Related Art FIG. 5 is a view showing the structure of a scanner which is an image reading apparatus of this type. In FIG. 5, reference numeral 1 denotes a contact glass as a document table formed of a transparent glass material or the like; A sensor body 3, a light source for illuminating the original on the contact glass 1, a lens 4 as an optical lens for forming an image of the original illuminated by the light source 3 on a light receiving surface of a line sensor 5 as a photoelectric conversion element An array 6 is a height adjusting member screwed to the image sensor main body 2, and an elasticity 7 is supported by a base 8 fixed to the image reading apparatus main body and urges the image sensor main body 2 to press against the contact glass 1. It is constituted by a member 7. In this scanner, a document closely mounted on the contact glass 1 is transported in a direction (sub-scanning direction) orthogonal to the longitudinal direction (main scanning direction) of the line sensor 5 and synchronized with the transporting operation of the document. Image data is sequentially read. The image data photoelectrically converted by the line sensor 5 is transmitted to an image processing unit after A / D conversion.

[0003]

In the contact type image sensor used in this image reading apparatus, a light beam emitted from a light source 3 is reflected from a contact glass 1 (original image) and is incident on a lens array 4 so that a line is formed. In order to form an image on the sensor 5, it is necessary to separate the sensor and the contact glass (original document) by a predetermined distance unique to the sensor. If the separation distance is not accurate, the amount of light applied to the line sensor decreases. As a result, accurate reading of an image cannot be performed. In particular, when reading multi-tone data or a color image, these problems have been remarkably exhibited. In order to solve this problem, in a conventional apparatus, a mechanism for adjusting the distance between the sensor body and the contact glass, that is, a screw that can be screwed into and retracted from the sensor body at a portion of the sensor body 2 facing the contact glass 1. The distance between the sensor and the contact glass is adjusted by adjusting the amount of advance of the screw. However, in this adjustment mechanism, it is difficult to balance the urging force of the elastic member and the position adjustment mechanism in the longitudinal direction of the sensor. If the position adjustment is performed with only one of the ends, the sensor 2 may be twisted. As a result, the focal length of the line sensor is not uniform, and the density of the read image data is uneven. Further, since the sensor body is directly urged against the contact glass by the elastic member, when the sensor 2 is deformed by thermal contraction due to a change in the ambient temperature, the sensor body 2 is deformed so as to warp. This also causes a problem that the focal length of the line sensor cannot be made uniform.

The present invention has been made to solve these problems, and an object of the present invention is to provide a contact type image sensor that can adjust a position with respect to a contact glass without deforming a sensor main body.

[0005]

In order to solve the above-mentioned problems, the present invention provides a line sensor for photoelectrically converting an original image,
A contact-type image sensor main body having a light source for illuminating a document and a lens array for forming an image of the illuminated document on the line sensor is supported by a sensor support member having an L-shaped cross section, and the sensor support is provided. An elastic member is provided between the member and the base fixed to the main body of the image reading apparatus, and an elastic member for urging the sensor support member and the base closer to each other when the sensor support member separates from the base is supported by the sensor support member. And a sensor position adjusting means for adjusting the separation distance between the sensor support member and the base against the urging force of the elastic member.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A contact type image sensor according to the present invention will be described below with reference to the drawings. FIGS. 1 to 4 are diagrams showing the configuration of a contact image sensor of the present invention and an image scanner employing the same, and the same reference numerals are given to the same components as those of the above-described conventional device.

The image sensor according to the present invention generally includes a contact type image sensor main body 2, a sensor supporting member 9 for supporting the image sensor main body 2, a base 8 fixed to a frame or the like of the image scanner main body, and a sensor supporting member 9. And base 8
Leaf spring 7 as an elastic member interposed between and supporting each other
It consists of. As shown in FIG. 2, the image sensor main body 2 is integrally formed with protrusions 21 at both ends in the longitudinal direction (main scanning direction), and the protrusions 21 are formed on the sensor support member 9. It is supported by being inserted into the support hole 92. Further, on the opposite side of the image sensor main body 2 where the projection 21 is formed, a pressing member 91 formed according to the outer shape of the sensor main body 2 is fitted, and an end of the pressing member 91 is shown in FIG. By fixing the sensor main body 21 to the sensor support member 9 with screws as described above, the sensor main body 21 is provided so as to be supported by the sensor support member 9 without rotating around the protrusion 21. The sensor support member 9 supporting the image sensor main body 2 is attached to a base 8 fixed to a frame or the like of the image scanner main body via a leaf spring 7 as an elastic member. Further, the base 8 is provided with a screw 6 as a sensor position adjusting means which is screwed into the screw hole 81 and is provided so as to be able to advance and retreat.
The tip of the screw 6 is provided so as to penetrate the leaf spring 7 and contact the bottom surface of the sensor support member 9.

Next, the operation of adjusting the sensor position in the contact type image sensor of the present invention will be described. In the case shown in FIG. 4, it is assumed that the right portion of the sensor body 2 has a problem such as a large separation distance from the contact glass 1 and a small irradiation amount of the light source 3. At this time, the operator turns the screw 6 serving as the height adjusting member and screws it in the direction of the sensor main body 2 (the direction of the arrow in the figure). This allows
The sensor support member 9 in contact with the tip of the screw 6 is
It is pressed and displaced in the direction of the contact glass 1 against the restoring force of the leaf spring 7 (lower view in FIG. 4), whereby the sensor main body 2 and the contact glass 1 approach each other. At this time, one end of the sensor support member 9 is still supported, and only the right side of the figure receives the force due to the screwing of the screw 6, so that the sensor support member 9 receives the rotational force in the counterclockwise direction of the figure. It will be. However, as shown in FIGS. 1 and 2, the sensor support member 9 in the contact type image sensor of the present invention is formed in an L-shape in cross section having a vertical side 93 from a bottom surface thereof. In this sensor height position adjusting operation, the height adjusting member 6 and the elastic member 7 are used.
Even if a greater force is applied, the deformation can be reduced as much as possible because the second moment of area is large. Therefore,
The image sensor main body 2 does not warp in the main scanning direction, thereby making it possible to perform position adjustment while keeping the focal length of the line sensor 5 uniform. When the screw 6 is returned from the state shown in the lower view of FIG. 4, the sensor support member 9 moves in the direction of the base 8 in accordance with the return amount of the screw 6 due to the restoring force of the leaf spring 7, whereby the image sensor body is 2 and the contact glass 1 are separated from each other.

Further, by forming the sensor supporting member 9 by BMC (bulk molding compound) made of an unsaturated polyester resin which is a thermosetting molding material, it is possible to obtain a sensor supporting member having an extremely small deformation amount. This makes it possible to improve the adjustment accuracy.

Further, according to the contact type image sensor of the present invention, the deformation of the image sensor main body 2 can be allowed in the main scanning direction, whereby the image sensor main body 2 is moved in the main scanning direction due to a temperature change of the surrounding environment. Even in the case of contraction, the problems such as warpage or breakage of the sensor can be eliminated, and the focal length of the line sensor can be kept uniform.

[0011]

As described above in detail, in the contact type image sensor of the present invention, the line sensor for photoelectrically converting the original image, the light source for illuminating the original, and the illuminated original image are formed on the line sensor. A contact-type image sensor main body having a lens array is supported by a sensor support member having an L-shaped cross section, and the sensor support is provided between the sensor support member and a base fixed to the image reading apparatus main body. When the member and the base are separated from each other, an elastic member for urging the member and the base toward each other is interposed and supported by the elastic member, and acts on the sensor supporting member to oppose the urging force of the elastic member. The sensor position adjusting means for adjusting the separation distance of the sensor is provided, so that the position with respect to the contact glass can be adjusted without deforming the sensor body. An effect.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a scanner that employs a contact image sensor of the present invention.

FIG. 2 is a diagram illustrating a configuration of a contact image sensor according to the present invention.

FIG. 3 is a perspective view showing a configuration of a contact type image sensor of the present invention.

FIG. 4 is a diagram for explaining a sensor position adjusting operation in the contact type image sensor of the present invention.

FIG. 5 is a cross-sectional view illustrating a configuration of a conventional contact image sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Contact glass (document table) 2 Image sensor main body 3 Light source 4 Lens array 5 Line sensor 6 Sensor position adjusting member 7 Elastic member 8 Base 9 Sensor support member

Claims (1)

[Claims] A line sensor for photoelectrically converting a document image;
A light source for illuminating the original, and a contact-type image sensor main body having a lens array for forming an image of the illuminated original on the line sensor; a sensor support member having an L-shaped cross section for supporting the image sensor main body; An elastic member interposed between the sensor support member and a base fixed to the image reading apparatus main body, and for urging the sensor support member and the base closer to each other when the sensor support member separates from the base, acting on the sensor support member; And a sensor position adjusting means for adjusting the separation distance between the sensor support member and the base against the urging force of the elastic member.