JP2946121B2 - Contact image sensor - Google Patents

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 mainly used for an image reader, a facsimile or the like.

[0002]

2. Description of the Related Art Conventionally, as shown in FIGS. 6 and 7, a contact type image sensor of this type has a reading glass 102, a reading glass 102, a frame 101 made of an aluminum alloy which is a conductor.
Although optical components such as a bottom plate 103, a side plate 104, an LED array 105, a selfoc lens 106, and a sensor substrate 107 are incorporated, the frame 101 is processed into its final shape, and has an adverse effect on an optical system. In order to avoid surface oxidation, a non-conductive black alumite treatment is applied. Therefore, the frame 101 and
Electrical continuity with the bottom plate 103, the side plate 104, and the like covering the optical component was not established.

[0003]

For this reason, even if the above-mentioned bottom plate 103, side plate 104, etc. are mounted so as to surround the frame 101, the power of shielding radio waves is weak.
On the contrary, when the close contact type image sensor is incorporated in an apparatus such as an image reader as described above due to the antenna effect, the following problem may occur.

That is, when the contact image sensor operates, a radio wave generated on the sensor substrate 107 is transmitted to the frame 10.
It is difficult to confine by the configuration of the bottom plate 103, the side plate 104, and the like, and radio waves are likely to leak to the outside, so that radiation noise characteristics may deteriorate. In addition, for the same reason, since the power of shielding radio waves that have entered from outside the contact type image sensor is weak,
The operation of the contact type image sensor may become unstable. If the ground wire is frequently used or radio wave shielding tape is used as a countermeasure against such a problem, this causes a cost increase.

[0005] The above-mentioned problems are to respond to the recent tightening of radiation noise regulations and to increase the operating clock of the contact image sensor in order to improve the reading resolution and reading speed. It has become a more serious problem in responding to the increase, enhancement, reduction in resistance to external noise, and the like.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and when the frame is connected and fixed to a member fixed to the frame, an electric conduction state is easily exhibited, and a high frequency noise blocking effect is obtained. It is an object of the present invention to provide a close contact type image sensor having the following configuration.

[0007]

Therefore, in the present invention,
Illuminating means for illuminating the image information surface of the original; imaging means for imaging the reflected light from the image information surface of the original by the illuminating unit at an equal magnification; and A light receiving element that performs photoelectric conversion and reads image information, and the illumination unit, the image forming unit, and a frame that integrally holds the light receiving element,
In a contact image sensor having a member fixed to the frame, the frame is made of a conductive material,
In addition, a non-conductive film is formed on the surface of the frame, and the member fixed to the frame has at least a surface made of a conductive material, and the frame and the member fixed to the frame are Are fixed so that they are electrically connected to each other.

[0008] Alternatively, the frame and the member fixed to the frame are each made of a conductive material, and each of them has a non-conductive film formed on its surface. The members are fixed to each other so that the members fixed to the frame have electrical continuity.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIGS. 1 (a), 1 (b) and 2, reference numeral 1 denotes a frame of a contact type image sensor, on which a reading glass 2 and a sensor element 4 as a light receiving element are provided. The sensor board 3, selfoc lens 5, side plates 9, 10 as imaging means, bottom plate 16 and mounting plate 22 as members fixed to the frame 1, LED array 20 as lighting means, etc. are mounted. is there. In particular, in this embodiment, the self-fox lens 5 is fixed with lens fixing screws 6, 7, and 8, the side plates 9, 10 are fixed with side plate fixing screws 11, 12, and the bottom plate 16 has engaging portions on both sides thereof. 17 and 18 which are fixed in a state where they are engaged with engaging portions formed on both sides of the frame 1. The sensor substrate 3 is connected to the frame 1 via a sensor substrate fixing rubber shaft 19. And the bottom plate 16, and the LED array 20 is fixed at 21 with LED array fixing screws. The frame 1 is adhered and fixed to the mounting plate 22 via a mounting plate adhesive 23, and the mounting plate 22 is fixed to the apparatus main body 26 by a contact type image sensor fixing screw 27. Reference numeral 24 denotes a mounting plate side document guide, 25 denotes a lens side document guide, and 28 denotes a document.

The frame 1 is formed by extruding an aluminum alloy into a final shape by subjecting the extruded material to a secondary processing such as a cutting process. In order to avoid an adverse effect on an internal optical system and surface oxidation, the frame 1 is black. Anodizing is performed, and as a result, a non-conductive film is formed on the surface of the frame 1.

The reading glass 2 is chamfered on the document inflow side to prevent the document from being caught. Side plate 9,1
Reference numeral 0 denotes a plate spring made of stainless steel, which is fixed to the frame 1 by side plate fixing screws 11 and 12, respectively. Further, the reading glass 2 includes reading glass adhesive layers 13, 14,
15, the center of the frame 1, the side plate 9,
It is fixed to 10. The bottom plate 16 is formed by extruding an aluminum alloy into a final shape by performing a cutting process. The surface of the bottom plate 16 is subjected to alumite treatment in order to avoid a change in surface state such as oxidation.

The LED array 20 has L on its substrate.
An ED chip, a cylindrical lens, and the like are mounted. The mounting plate 22 is a sheet metal made of steel,
In order to avoid a change in the surface state such as oxidation, and to improve the conductivity, a surface treatment having high high-frequency conductivity such as nickel plating, tin plating, and aluminum plating is performed.

In the configuration of the present embodiment, the mounting plate-side document guide 24 is a guide plate for allowing a document to flow smoothly into the reading glass 2, and is fixed to the apparatus main body 26. In the configuration of the present embodiment, the lens-side document guide 25 is a guide plate for allowing a document to flow out smoothly from the reading glass 2, and is fixed to the apparatus main body 26.

The original 28 smoothly flows into the reading glass 2 along the original guide 24 on the mounting plate, and flows out of the reading glass 2 along the original guide 25 on the lens. At this time, the light beam emitted from the LED array illuminates the reading glass 2 side of the original 28 on the reading glass 2, and an image drawn on the original 28 is formed on the sensor element 4 by the Selfoc lens 5. You. Thus, the image photoelectrically converted by the sensor element 4 is amplified on the sensor substrate 3 and output to the outside of the contact type image sensor.

The side plates 9 and 10 are made of stainless steel, so that their surfaces are conductive. The side plate fixing screws 11 and 12 for fixing this to the frame 1 are also made of steel, and the surface thereof is plated with nickel having good conductivity. Normally, as shown in FIG. 3A, the formation (tapping) of the tapping pilot hole 29 and the screw hole 30 of the frame 1 is performed before the alumite treatment. However, in this embodiment, as shown in FIG. 3B, after the tapping pilot hole 30 is formed in the frame 1, anodizing is performed, and then tapping is performed on the frame 1. Is removed. As described above, in this embodiment, since the tapping process is performed only after the alumite treatment in order to establish electrical conduction, there is an advantage that the cost is not increased due to an increase in the number of processes.

When the screws are fixed in this way, it is possible to establish electrical continuity between the frame 1 and the side plate through the side plate fixing screws 11 and 12. If necessary, not only conduction by the side plate fixing screws 11 and 12 but also conduction from the contact surfaces 31 and 32 between the frame 1 and the side plates 9 and 10 may be performed to increase the conduction area. In this case, it is necessary that a conductive ground is exposed on the side of the frame 1 instead of the alumite film. There are two types of means for exposing the background as described below.

In the means shown in FIG. 4, first, after the alumite treatment is performed on the frame 1, a necessary portion is subjected to secondary processing to remove the alumite film. The secondary processing includes, for example, milling. Also, removal of the alumite film by the tapping is one type of the secondary processing.

The feature of this processing is that the shape of the portion where the background is exposed changes. Therefore, if the necessary secondary processing is performed for another purpose, and at the same time the background at the required location can be exposed, the special processing for exposure of the background required in the present invention can be omitted. Will be.

In the means shown in FIG. 5, an alumite film is not formed on a necessary portion during the alumite treatment. That is, in the portion of the frame 1 where the background is exposed,
This is a field in which masking is performed in advance, and after alumite processing, the mask is removed. As a result, the ground at the required location is exposed without undergoing the alumite treatment. The masking is performed by applying a resist not affected by the alumite treatment,
This is performed by attaching a masking tape or the like.

The feature of this processing is that the shape of the portion exposing the background does not change. It is also suitable for exposing a wide range.

In any of the processing means, the effect of exposing the background is a portion which receives the pressure due to the tightening of the screw, and in this embodiment, is around the tap. Further, it is desirable that the exposure range be wider in the contact surface, and it is desirable that the exposure range be at least larger than the contact area of the screw bearing surface.

In this embodiment, the bottom plate 16 is made of the same aluminum alloy as the frame 1 and is alumite-treated, so that its surface is not conductive. In this case, in order to enable electrical conduction between the frame 1 and the bottom plate 16, it is necessary to make the contact surfaces 33 and 34 electrically conductive. For this reason, it is necessary to expose the whole or a part of the background of the contact surface, and the above-described two means can be selectively used as the background exposure means for this purpose. As in the case described above, the exposed part of the background is particularly effective in the part receiving the pressure, and the exposed area is preferably wider in the contact surface.

The surface of the mounting plate 22 is conductive. When bonding this to the frame 1, the bonding surface 3
It is necessary to establish electrical continuity via 5. For this, first, the alumite film on the bonding surface is removed, and then, a conductive adhesive 23 is applied in a layer form. The adhesive used here may be an ordinary adhesive mixed with a conductive substance such as copper powder or carbon powder. It is desirable that the area from which the alumite film is removed is large in view of its conductivity and also in consideration of the risk of the film peeling off. Further, as for screws for fixing non-conductive parts, such as lens fixing screws 6, 7, 8 which are not described in the above embodiment, the order of processing of non-conductive film treatment and tapping does not matter. A convenient processing / processing order may be adopted in the process of manufacturing the image sensor.

In the above embodiment, the side plate is made of stainless steel, the screw is made of iron and steel, and the mounting plate is made of steel plate with conductive plating. The above materials can be changed. For example, the side plate may be formed by conductive plating on an iron steel plate, and the screws and the mounting plate may be made of stainless steel. These may be copper or another metal material, or may be a plastic material mixed with copper powder or carbon powder to have conductivity. Further, a non-conductive plastic or the like which is provided with a conductive plating such as nickel may be used.

The material of the frame is not limited to aluminum alloy as long as it is a conductive material, and the surface film may be formed by a method other than alumite treatment such as painting if non-conductive. It does not matter.

[0026]

As described above, when a frame in which a conductive material is applied with a non-conductive film is used in a contact type image sensor, electrical conduction between the frame and a member to be mounted on the frame is established. By taking this, when the close contact image sensor is operated, the radio wave generated on the sensor substrate can be confined by the frame, the bottom plate, the side plate, etc., and the antenna effect is less likely to occur, so the leakage of the radio wave to the outside is reduced, Radiation noise characteristics do not deteriorate. Further, for the same reason, the force for shielding radio waves coming from outside the contact type image sensor becomes stronger, and the possibility that the operation of the contact type image sensor becomes unstable due to the radio waves coming from the outside is also eliminated. . As a countermeasure for this problem,
There is no need to use a ground wire or radio wave shielding tape, and the cost is not increased.

[Brief description of the drawings]

FIG. 1 (a) is a front view of one embodiment of the present invention.

FIG. 1 (b) is an enlarged front view of a main part thereof.

FIG. 2 is an enlarged vertical sectional side view of the present invention.

FIG. 3A is an explanatory diagram of an alumite processing sequence.

FIG. 3B is an explanatory diagram of the order of tapping processing.

FIG. 4 is an explanatory view of a processing procedure for obtaining a ground without an alumite film.

FIG. 5 is an explanatory diagram of another processing procedure for producing a ground without an alumite film.

FIG. 6 is a front view of a conventional contact image sensor.

FIG. 7 is an enlarged side view of a conventional contact image sensor.

[Explanation of symbols]

 Reference Signs List 1 frame 2 reading glass 3 sensor substrate 4 sensor element (light receiving element) 5 selfoc lens (imaging means) 6, 7, 8 lens fixing screw 9, 10 side plate 11, 12 side plate fixing screw 13, 14, 15 reading glass bonding Layer 16 Bottom plate (member fixed to frame) 17, 18 Engagement portion of bottom plate 19 Sensor substrate fixing rubber shaft 20 LED array (illumination means) 21 LED array fixing screw 22 Mounting plate (fixed to frame) 23) Adhesive of mounting plate 24 Mounting plate-side document guide 25 Lens-side document guide 26 Device body 27 Close-contact type image sensor fixing screw 28 Document 29 Tapping pilot hole of frame 1 30 Screw hole 31, 32 Between frame 1 and side plate Contact surface 33, 34 Contact surface between frame 1 and bottom plate 35 Adhesion surface of mounting plate 22

Claims (6)

(57) [Claims] An illumination unit configured to illuminate an image information surface of the original; an imaging unit configured to form a reflection light from the image information surface of the original by the illumination unit at an equal magnification; A contact type image sensor having a light receiving element for photoelectrically converting the reflected light and reading image information, a frame integrally holding the illuminating means, the image forming means, and the light receiving element, and a member fixed to the frame. The frame is made of a conductive material, has a non-conductive film formed on its surface, and is configured in a state where there is no non-conductive film on a part or all of a contact surface with a member fixed to the frame. The member fixed to the frame has at least a surface made of a conductive material, and the frame and the member fixed to the frame are separated from each other via the contact surface by pressure due to elasticity of the member. A contact-type image sensor, which is fixed by contact so as to have electrical continuity. 2. The method according to claim 1, wherein the contact surface is formed by forming a mask beforehand when forming the non-conductive film on the frame, and removing the mask after forming the film. The contact type image sensor according to claim 1, wherein: 3. The close contact according to claim 1, wherein the contact surface is formed by forming the non-conductive film on the frame and then subjecting the non-conductive film to secondary processing. Type image sensor. 4. An illuminating means for illuminating an image information surface of a document, an image forming means for forming light reflected from the image information surface of the document by the illuminating unit at an equal magnification, and A contact type image sensor having a light receiving element for photoelectrically converting the reflected light and reading image information, a frame integrally holding the illuminating means, the image forming means, and the light receiving element, and a member fixed to the frame. The frame is made of a conductive material, has a non-conductive film formed on its surface, and is configured in a state where there is no non-conductive film on a part or all of a contact surface with a member fixed to the frame. At least the surface of the member fixed to the frame is made of a conductive material, and the frame and the member fixed to the frame are electrically connected to each other via a conductive adhesive at the contact surface. A contact image sensor which is fixed so as to be conductive. 5. When forming the non-conductive film on a member fixed to the frame and the frame, the contact surface is masked in advance, and after forming the film,
The contact type image sensor according to claim 4, wherein the contact type image sensor is configured by removing the masking. 6. The contact surface is formed by forming the non-conductive film on the frame and a member fixed to the frame, and then subjecting the corresponding portion to secondary processing. The contact type image sensor according to claim 4, wherein: