JP2002237924A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reader, that can surely suppress radiation of an unwanted electromagnetic waves by surely grounding a ground terminal of a board on which a photoelectric conversion element consisting of a CCD sensor or the like is mounted, even when the mounting position of the photoelectric conversion element consisting of the CCD sensor or the like is made adjustable. SOLUTION: The image reader is provided with the photoelectric conversion element, whose position is fitted adjustably is provided via an elastic member to a mount member onto which optical components are fixedly fitted, and reads an image formed by the optical components by using the photoelectric conversion element. The reader is also provided with a support member, that supports the photoelectric conversion element and is electrically connected to the ground terminal of a drive circuit which drives the photoelectric conversion element, and a conductive member that conducts the support member and a conductive shield at a plurality of points, is placed between the photoelectric conversion element, and the conductive shield covering the drive circuit and is elastically deformed with a force smaller than that of the elastic member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus for optically reading an image of a black-and-white or color original, and more particularly, to a CC which is a photoelectric conversion element of the image reading apparatus.
The present invention relates to an image reading apparatus that can effectively suppress emission of unnecessary electromagnetic waves when driving a D sensor or the like.

[0002]

2. Description of the Related Art Conventionally, as an image reading apparatus of this type, an apparatus configured as follows is generally used. As shown in FIG. 8, the image reading apparatus illuminates an image of a document (not shown) placed on a platen glass 101 with a light source 102 and a reflector 103, and reflects a reflected light image from the document on a full-rate mirror. The image is reduced and formed on a photoelectric conversion element 108 such as a CCD (Charge Coupled Device) sensor or the like by an imaging lens 107 via a 104 and half-rate mirrors 105 and 106, and a document is formed by the CCD sensor 108 as the photoelectric conversion element. Is configured to read the image. FIG.
Reference numeral 110 denotes a platen cover for holding down a document.

In the above-described image reading apparatus, a driving circuit including an IC, an LSI, and the like for driving a CCD sensor serving as a photoelectric conversion element is provided together with the CCD sensor. The driving circuit controls the CCD sensor. A control signal such as a clock has a very high frequency of several tens of MHz due to an increase in reading speed and an increase in resolution, and thus tends to strongly emit unnecessary electromagnetic waves. When unnecessary electromagnetic waves are emitted from the drive circuit that controls the CCD sensor, the electromagnetic waves become noise, causing malfunctions or deteriorating the image reading device or a copying machine equipped with the image reading device. There is a fear that.

In such a case, the CCD sensor and the driving circuit, which are sources of unnecessary electromagnetic waves, are securely covered with a metal shield, and the ground terminal of the substrate on which the CCD sensor is mounted is connected to the surrounding metal. Means for suppressing radiated electromagnetic waves by conducting (grounding) the shield at multiple points is employed.

[0005]

However, the prior art described above has the following problems. That is, in the case of the above-described conventional image reading apparatus, FIG.
As shown in FIG. 2, the substrate on which the CCD sensor 108 is mounted is placed on another imaging lens 1 so that an image is correctly formed.
It is necessary to adjust the position with respect to an optical component such as 07.
Therefore, the CCD sensor 108 cannot be fixed, and it is necessary to adjust the tilt angle, the vertical position, and the like. Therefore, it is difficult to reliably ground the ground terminal in the substrate on which the CCD sensor is mounted with screws or the like. At present, one point is grounded by a conducting wire having the following. As a result, the other of the ground terminals in the substrate on which the CCD sensor is mounted is in an open state, and the other ground terminal in the open state serves as an antenna to reliably suppress the emission of unnecessary electromagnetic waves. There was a problem that it was not possible.

Accordingly, the present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to make it possible to adjust a mounting position of a photoelectric conversion element such as a CCD sensor. However, an object of the present invention is to provide an image reading device that can reliably ground a ground terminal of a substrate on which a photoelectric conversion element including the CCD sensor or the like is mounted, and can reliably suppress emission of unnecessary electromagnetic waves. .

[0007]

That is, according to the first aspect of the present invention, there is provided a photoelectric conversion element in which the position is adjustable via an elastic member to a mounting member to which an optical component is fixed. In an image reading device that reads an image formed by the optical component by a photoelectric conversion element, the image reading apparatus holds the photoelectric conversion element and is electrically connected to a ground terminal of a driving circuit that drives the photoelectric conversion element. Between the holding member and the conductive shield covering at least the photoelectric conversion element and the drive circuit, a member for conducting the holding member and the conductive shield at a plurality of points, with a smaller force than the elastic member. It is configured to provide a conductive member that is elastically deformed.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 FIG. 2 is a schematic diagram showing an image reading apparatus according to Embodiment 1 of the present invention.

As shown in FIG. 2, the image reading apparatus has an image reading apparatus main body 1 having an open upper surface, and a document (not shown) is placed in the upper opening of the image reading apparatus main body 1. Platen glass 2 is attached. A document (not shown) is placed on the platen glass 2 at a predetermined position with an image to be read facing downward. A platen cover 3 for pressing a document onto a platen glass 2 is provided at an upper portion of the image reading apparatus main body 1 so as to be openable and closable.

A lamp 4 as an illuminating means for illuminating an image of a document (not shown) placed on a platen glass 2 and a light radiated from the lamp 4 are provided inside the image reading apparatus main body 1. A reflector 5 for efficiently condensing the document surface, a full-rate mirror 6 for horizontally reflecting the reflected light image from the document, and two half-rate mirrors for reflecting the reflected light image from the full-rate mirror 6 in a folded manner. 7, 8 and these two half-rate mirrors 7,
Imaging lens 9 as an optical component for reducing and imaging the reflected light image from 8, and sagittal stopper 11 as a light shielding means
And a line image sensor 12 as a photoelectric conversion element such as a CCD (Charge Coupled Device) image sensor for converting a light image formed by the imaging lens 9 into an electric signal. As the imaging lens 9, for example, a double Gauss type lens is used. In order to read a color image, a color CCD image sensor that reads a color image in three colors of B (blue), G (green), and R (red) is used as the CCD image sensor 12.

The lamp 4 and the reflector 5 and the full-rate mirror 6 are mounted on a full-rate carriage (not shown), and the full-rate carriage is configured to move at a predetermined speed V along the sub-scanning direction. I have. The two half-rate mirrors 7 and 8 are
It is mounted on a half-rate carriage (not shown),
The half-rate carriage is also configured to move at half the speed of the full-rate carriage 1/2 V in the sub-scanning direction. As a result, the original placed on the platen glass 2 has a lamp 4, a reflector 5 and a full rate mirror 6 moving at a predetermined speed,
By using the two half-rate mirrors 7 and 8, the entire image is scanned and exposed on the CCD image sensor 12 via the imaging lens 9 without changing the optical path length.

In the above image reading apparatus, FIG.
As shown in FIG. 2, an image of a document placed on the platen glass 2 is illuminated by light emitted from a lamp 4 and collected by a reflector 5, and a reflected light image from the document is reflected by a full-rate mirror 6. Half-rate mirror 7,
The image is reduced and imaged on the CCD image sensor 12 by the image forming lens 9 via 8. At this time, a part of the reflected light image from the document, which is reduced and formed on the CCD image sensor 12 by the image forming lens 9, is shielded by the sagittal stopper 11. At this time, the CCD image sensor 12 performs photoelectric conversion according to the intensity of incident light for each pixel, thereby obtaining an image signal (RGB signal) corresponding to a document image.

By the way, in this embodiment, a photoelectric conversion element, whose position is adjustable via an elastic member, is provided on a mounting member to which the optical component is fixed, and an image is formed by the optical component. An image reading device that reads the image obtained by the photoelectric conversion element, a holding member that holds the photoelectric conversion element and is electrically connected to a ground terminal of a driving circuit that drives the photoelectric conversion element, and the photoelectric conversion element A conductive member that conducts the holding member and the conductive shield at a plurality of points between the conductive member and the conductive member that is elastically deformed with a smaller force than the elastic member. I have.

FIG. 1 is an exploded perspective view showing an image reading section of the image reading apparatus.

In FIG. 1, reference numeral 9 denotes an imaging lens as an optical component. The imaging lens 9 is provided on a lens plate 10 as an attachment member and a metal band 13.
And is attached in a fixed state by screwing. The lens plate 10 is slidably mounted on guide rails 14 and 15 arranged in parallel on both sides in the width direction. A CCD image sensor 12 is provided on the lens plate 10.
Sensor mounting plate 16 as mounting member for mounting
Are attached while being fixed by screws. The sensor mounting plate 16 is formed by bending a sheet metal pressed into a predetermined shape into a predetermined shape.

As shown in FIGS. 1 and 3, the sensor mounting plate 16 has a base portion 17 fixed on the lens plate 10 by screws, and the base portion 17 is provided on the CCD image sensor 12 side. The end portion is provided with an upright plate portion 18 which is bent in a vertically upright state. The upright plate portion 18 of the sensor mounting plate 16 is provided at its upper end with a horizontal plate portion 19 that is bent horizontally toward the imaging lens 9 side. The distal end portion 20 is configured to be bent downward to increase the rigidity of the horizontal plate portion 19.

Further, on the horizontal plate 19 of the sensor mounting plate 16, a sensor holding bracket 21 as a holding member which is mounted with the substrate of the CCD image sensor 12 fixed is used to adjust the mounting position of the CCD image sensor 12. Mounted as possible. The sensor holding bracket 21 is formed by bending a sheet metal pressed into a predetermined shape into a predetermined shape.

The sensor holding bracket 21 is shown in FIG.
As shown in FIGS. 3 and 4, a horizontal plate portion 22 is provided in parallel with the horizontal plate portion 19 of the sensor mounting plate 16, and the horizontal plate portion 22 is vertically disposed on the CCD image sensor 12 side. A downwardly bent hanging plate portion 23 is provided. As shown in FIG. 4, the horizontal plate portion 22 of the sensor holding bracket 21 is bent such that a central portion 22a is slightly lower than left and right end portions 22b and 22c. As shown in FIG. 3, the left and right ends of the horizontal plate 22 are bolts 24 inserted from below into the horizontal plate 19 of the sensor mounting plate 16 and the horizontal plate 19 of the sensor mounting plate 16. Bolt 24 on top
Of the sensor mounting plate 16 by a holding spring 25 formed of a compression spring provided in a state where the sensor mounting plate 16 is For the plate 19,
The position in the up-down direction is attached so that adjustment is possible.

The sensor holding bracket 21
As shown in FIG. 3, a vertical plane perpendicular to the optical axis of the CCD image sensor 12 attached to the sensor holding bracket 21 is adjusted by adjusting the amount of tightening of the adjusting screws 26 provided on both right and left ends. It is possible to adjust the vertical position and the inclination angle in the inside.

A control board 27 on which the CCD image sensor 12 is mounted is fixed to the sensor holding bracket 21 in a fixed state. At both ends of the sensor holding bracket 21, there are provided legs 28 bent in an L-shape so as to face each other toward the CCD image sensor 12 side. The control board 27 to which the image sensor 12 is attached is attached by screws 29 so as to be parallel to the hanging plate portion 23 of the sensor holding bracket 21. At this time, the sensor holding bracket 21
Are electrically connected to ground terminals printed on the control board 27 on which the CCD image sensor 12 is mounted.

The control board 27 on which the CCD image sensor 12 is mounted emits unnecessary electromagnetic waves because a control signal such as a clock for driving the CCD image sensor 12 has a very high frequency. Cheap.
Therefore, in order to suppress this unnecessary electromagnetic wave, the ground level of the control board 27 to which the CCD image sensor 12 is attached is set to be substantially the same as the potential of the stable (less fluctuating) lens frame 10, A so-called shield is provided to make the potential substantially the same as the potential of the frame 10 or to cover the periphery with a metal having substantially the same potential as the lens frame 10. Therefore, as shown in FIGS. 1, 4, and 5, on the lens plate 10,
A metal lens cover 30 serving as a conductive shield is attached by screws so as to cover the entire image forming lens 9, the CCD image sensor 12, and the control board 27. In FIG. 5, reference numeral 40 denotes an adjustment hole for performing an adjustment as needed after the metal lens cover 30 is attached.

Further, in this embodiment, the central portion 22a of the horizontal plate portion 22 of the sensor holding bracket 21 is provided.
Between the sensor holding bracket 21 and the metal lens cover 30, at least two points are provided.
More preferably, a leaf spring 31 as a conductive member which is a member that conducts at three or more points and is elastically deformed with a smaller force than the holding spring 25 as the elastic member is provided by means such as screwing. Have been. This leaf spring 31
Is formed by a thin plate member made of, for example, phosphor bronze, and has two small contact points 32 on both sides at one end and one narrow contact point at the center as shown in FIG. A wide contact 33 is provided. The wide contact 33 of the leaf spring 31 is provided with a large cut-out portion 34 at the center so as to reduce the spring constant.
The contact 32 and the contact 33 of the leaf spring 31 are formed in an arc shape so that the tips thereof surely contact the inner surface of the metal lens cover 30. When not in contact with the inner surface, its length and inclination angle are set so as to protrude above the inner surface of the lens cover 30.

In the above configuration, the image reading apparatus according to this embodiment includes the CCD sensor and the like even when the mounting position of the photoelectric conversion element such as the CCD sensor can be adjusted as follows. The ground terminal of the substrate on which the photoelectric conversion element is mounted can be reliably grounded, and the emission of unnecessary electromagnetic waves can be reliably suppressed.

That is, in the image reading apparatus according to this embodiment, as shown in FIG. 2, the image of the original placed on the platen glass 2 is read by the lamp 4 and the reflector 5.
The reflected light image from the original is reduced and formed on the CCD image sensor 12 by the imaging lens 9 via the full-rate mirror 6 and the half-rate mirrors 7 and 8 while illuminating the full-rate mirror 6 and the half-rate mirrors 7 and 8. By moving the half-rate mirrors 7 and 8 in the sub-scanning direction, the entire image of the document is scanned and exposed on the CCD image sensor 12, and the CCD image sensor 12 converts the document image into an electric signal and reads it. It has become.

At this time, in the image reading apparatus, as shown in FIGS.
A drive circuit (not shown) including an IC, an LSI, and the like for driving the D image sensor 12 is provided on the drive board 27 together with the CCD image sensor 12. The drive circuit controls the CCD image sensor 12 by a control signal such as a clock. Since the reading frequency has become very high at several tens of MHz with the increase in reading speed and resolution, there is a tendency that unnecessary electromagnetic waves are radiated strongly.

In this embodiment, as shown in FIGS. 5 and 6, the ground terminal of the control board 27 on which the CCD image sensor 12 is mounted is connected to the sensor holding bracket 21 on which the control board 27 is mounted, and The metal lens cover 30 can be brought into contact with the metal lens cover 30 at multiple points via a leaf spring 31 provided on the sensor holding bracket 21, and the metal lens cover 30 is attached to the lens plate 30 via mounting screws. There are surely multiple points of contact. Therefore, the ground terminal of the control board 27 to which the CCD image sensor 12 is attached is connected to the frame of the image reading device via the lens plate 10 and grounded, or the potential of the lens plate 10 is set to substantially the same potential. And a stable ground level can be obtained. The sensor holding bracket 2
1 is a CCD using a holding spring 25 and an adjusting screw 26.
The trick position of the image sensor 12 can be adjusted. Therefore, even when the mounting position of the photoelectric conversion element such as a CCD sensor can be adjusted, the base on which the photoelectric conversion element such as the CCD sensor is mounted is mounted.
The ground terminal of the plate can be reliably grounded, and the emission of unnecessary electromagnetic waves can be reliably suppressed.

What is important here is that the position of the control board 27 on which the CCD image sensor 12 is mounted can be adjusted within a range adjustable with respect to the lens plate 10.
Holding spring 25 that enables adjustment of the position of control board 27
The force of the leaf spring 30 for realizing the contact with the lens plate 10 is weaker than the spring force described above, and does not affect the position adjustment.

Second Embodiment FIG. 7 shows a second embodiment of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals and described. , The photoelectric conversion element 12
A conductive member 31 provided between the conductive member 30 and the conductive shield 30 for covering the holding member 21 and the conductive shield 3- at a plurality of points. However, it is configured not to be a leaf spring formed on a thin plate member made of phosphor bronze but to be made of a conductive sponge.

The other configuration and operation are the same as those of the above-described embodiment, and the description thereof will be omitted.

Although the above embodiment has been described with reference to the case where the elastically deformable conductive member provided between the holding member and the conductive shield is provided on the holding member side, the invention is not limited to this. Of course, the conductive member may be provided on the conductive shield side.

[0032]

As described above, according to the present invention, the substrate on which the photoelectric conversion element is mounted can be grounded to the conductive shield at a plurality of points, so that the mounting position of the photoelectric conversion element can be adjusted. Even when it is possible, the ground terminal of the substrate on which the photoelectric conversion element is mounted can be reliably grounded, and the emission of unnecessary electromagnetic waves can be reliably suppressed.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a main part of an image reading apparatus according to Embodiment 1 of the present invention.

FIG. 2 is a schematic configuration diagram showing an image reading device according to Embodiment 1 of the present invention.

FIG. 3 is an exploded side view showing a main part of the image reading apparatus according to Embodiment 1 of the present invention.

FIG. 4 is an exploded perspective view showing a main part of the image reading device according to the first embodiment of the present invention.

FIG. 5 is a perspective view showing a main part of the image reading apparatus according to the first embodiment of the present invention.

FIG. 6 is a partially broken side view showing a main part of the image reading apparatus according to Embodiment 1 of the present invention.

FIG. 7 is a perspective view showing a conductive member of the image reading apparatus according to Embodiment 2 of the present invention.

FIG. 8 is a schematic configuration diagram showing a conventional image reading apparatus.

[Explanation of symbols]

9: imaging lens (optical component), 10: lens plate (mounting member), 12: CCD image sensor (photoelectric conversion element), 16: sensor mounting plate (mounting member), 2
1: sensor holding bracket (holding member), 30: metal lens cover (conductive shield), 31: leaf spring (conductive member).

Claims (1)

[Claims] 1. An image forming apparatus according to claim 1, further comprising: a photoelectric conversion element attached to the mounting member fixed with the optical component fixed thereto via an elastic member so as to adjust the position thereof. In an image reading device that reads by an element, a holding member that holds the photoelectric conversion element and is electrically connected to a ground terminal of a driving circuit that drives the photoelectric conversion element, and covers at least the photoelectric conversion element and the driving circuit An image, characterized in that a conductive member that conducts the holding member and the conductive shield at a plurality of points and that is elastically deformed with a smaller force than the elastic member is provided between the conductive member and the conductive shield. Reader.