JP4675347B2 - Image reading apparatus and image forming apparatus having the same - Google Patents

Description

  The present invention relates to an image reading apparatus such as a digital copying machine, a facsimile, and an image scanner, and an image forming apparatus including the image reading apparatus.

In a digital copying machine, a facsimile, an image scanner, and the like, a CCD sensor is often used to read an image of a document. Of course, a CCD sensor used for such a purpose needs to maintain a certain position with respect to the lens. Therefore, the problem is the deformation of the mounting substrate due to heat generation of components including the CCD sensor itself, heat of the lamp, and the like.

  In the apparatus as described above, although a cooling fan is provided, the internal temperature of the optical system unit including the image reading device becomes 40 ° C. or higher when continuously operated. The temperature of the substrate on which the CCD sensor is mounted is close to 60 ° C. When the temperature rises to this extent, the mounting board of the CCD sensor is warped by heat, and the position of the CCD sensor attached to the mounting board also changes. When the distance between the CCD sensor and the lens changes, the image is out of focus and the image is out of focus. In order to solve this problem, various proposals have been made so far. Examples thereof can be seen in Patent Documents 1 and 2.

  In the image reading apparatus described in Japanese Patent Application Laid-Open No. H10-228707, the outer shape of the CCD is held and bonded to the concave portion of the spacer to regulate the position of the CCD. The spacer is fixed to the position adjustment bracket with a fixing screw common to the electrical board. The CCD is soldered to the electrical board. The position adjustment bracket is fixed to the lens unit holding the lens and incorporated in the apparatus main body. Since the CCD is held by the spacer, the CCD is not misaligned even if the electrical substrate is warped or deformed.

In the image reading apparatus described in Patent Document 2, a substrate on which a solid-state image sensor array is mounted is fixed to a support member in a state where the substrate is bent in advance using a correction means. Thereby, even if the temperature rises or falls in the image reading apparatus, the substrate maintains a certain shape.
JP 2001-245098 A JP 2003-115978 A

  Conventional measures for preventing the displacement of the CCD have the following problems. First, in the case of the thing of patent document 1, the hand which prevents the curvature of an electrically equipped board | substrate is not given. While the CCD is held by the spacer and does not move, when the electrical substrate is warped away from the spacer, stress is applied to the soldered portion between the CCD lead and the electrical substrate. If the stress is excessive or the cumulative number of stresses increases, the soldered part is destroyed and there is a risk of causing poor contact.

  In the case of the device described in Patent Document 2, stress is generated in the solid-state image sensor array, which may affect the flatness of the imaging surface. In addition, the elasticity of the circuit board deteriorates due to secular change, and a warped state becomes natural, and if the temperature rises or falls, the shape of the board may change.

  The present invention has been made in view of the above points. A CCD that can keep the position of the CCD sensor constant regardless of the temperature change of the image reading apparatus and does not affect the mounting state of the CCD sensor on the substrate. An object is to provide a sensor mounting structure. It is another object of the present invention to provide an image forming apparatus that can stably form an image with good image quality by including such an image reading apparatus.

In order to achieve the above object, according to the present invention, there is provided an image reading apparatus for converging reflected light from a document surface onto a CCD sensor by means of a lens. A mounting substrate is disposed, the CCD mounting substrate is fixed to the support plate, the lead of the CCD sensor is inserted into the CCD mounting substrate through a through hole formed in the support plate and the insulating member, and the edge of the support plate is An elastic member having a pair of arms to be held is engaged with a support plate from the back of the CCD mounting substrate, and the pair of arms of the elastic member are fitted into notches formed at the edges of the support plate, respectively. The CCD mounting substrate is pressed against the support plate by the protrusion formed on the elastic member.

According to this configuration, since the CCD mounting substrate is pressed by the elastic member toward the support plate, the CCD mounting substrate does not warp in the direction away from the support plate, and the position and shape of the CCD mounting substrate do not vary. As a result, the position of the CCD sensor mounted on the CCD mounting substrate is also fixed. The mounting state of the CCD sensor on the CCD mounting substrate is also unchanged. Further, since the pair of arms of the elastic member are respectively fitted into the notches formed on the edge of the support plate, the elastic member does not shift after the arm holds the edge of the support plate.

According to the present invention, in the image reading apparatus configured as described above, the through-hole formed in the support plate is characterized in that two long holes through which the CCD sensor leads pass one by one are arranged in parallel. Yes.

  According to this configuration, the area of the through hole formed in the support plate is suppressed, and the strength of the support plate can be maintained.

According to the present invention, in the image reading apparatus configured as described above, the CCD mounting substrate is fixed to the support plate with a plurality of screws, and the driver element of the CCD sensor is located at the center of the CCD mounting substrate rather than the screws. It is characterized by being mounted at a far position .

  The driver element of the CCD sensor is a heat generating component. Since this driver element is mounted not at the center of the CCD mounting substrate on which the CCD sensor is disposed, but at a location farther than the screw that fixes the CCD substrate to the support plate, the heat generated by the driver element causes the mounting portion of the CCD sensor to There are few cases where the CCD sensor is distorted due to thermal deformation.

The present invention is also characterized in that the image forming apparatus includes a traveling body support device for an optical system configured as described above.

  According to this configuration, it is possible to provide an image forming apparatus that can stably form an image with good image quality.

  According to the present invention, the warpage of the CCD mounting substrate itself can be suppressed, the position of the CCD sensor can be fixed, and the mounting state of the CCD sensor with respect to the CCD mounting substrate can also be made unchanged. As a result, the image forming apparatus can stably form an image with good image quality.

  An embodiment of the present invention is shown in FIGS. 1-6. 1 is a schematic partial sectional view of an image forming apparatus equipped with the image reading apparatus of the present invention, FIG. 2 is a perspective view of the image reading apparatus, FIG. 3 is a perspective view of the image reading apparatus viewed from a different direction from FIG. FIG. 5 is a perspective view of the CCD mounting substrate fixed to the support plate, FIG. 5 is a perspective view of the CCD mounting substrate fixed to the support plate viewed from a different direction from FIG. 4, and FIG. 6 is an exploded perspective view of the components. .

  FIG. 1 shows an electrostatic copying machine 1 as an example of an image forming apparatus. What is depicted in FIG. 1 is a portion of the scanner unit 10 at the top of the electrostatic copying machine 1, and its outline will be described below. An opening 12 for exposing a document is formed on the top surface of the housing 11 of the scanner unit 10, and the opening 12 is covered with a contact glass 13. A cover 14 is disposed on the contact glass 13 to press the document against the contact glass 13 and prevent the document illumination light from leaking outside. The lid 14 is attached to the housing 11 so as to open and close with a side far from the operator as a fulcrum.

  A first traveling body 20 and a second traveling body 30 are disposed under the contact glass 13. The first traveling body 20 and the second traveling body 30 are held by a rail (not shown) so as to be slidable in the horizontal direction. It is a combination of a wire and a pulley that gives power for traveling to the first traveling body 20 and the second traveling body 30, but this is a well-known technique and is not a gist of the invention, so it will not be described in detail.

  The first traveling body 20 includes a light source 21, a collecting mirror 22 that collects light emitted from the light source 21 on the document surface on the contact glass 13, and reflected light from the document surface in the direction of the second traveling body 30. A first mirror 23 is mounted. The second traveling body 30 is mounted with a second mirror 31 and a third mirror 32 that sequentially reflect the reflected light from the first mirror and project it in the direction of the image reading device 40.

  The image reading device 40 includes a lens 41 that receives light from the third mirror 32 and a CCD sensor 42 that receives the light converged by the lens 41 and connects the images. The structure of the image reading device 40 will be described in detail later.

  When a “copy” button (not shown) of the electrostatic copying machine 1 is pressed, the first traveling body 20 moves by the set document width while projecting onto the document surface on the contact glass 13. . The second traveling body 30 sends the reflected document light from the first traveling body 20 to the image reading device 40 while following the first traveling body 20 at half speed. The reflected light converged by the lens 41 forms an image on the imaging surface of the CCD sensor 42. The image is digitally processed and a well known electrostatographic process is performed.

  The center of assembly of the image reading apparatus 40 is a chassis 43 made of sheet metal. A lens 41 is horizontally mounted on the upper surface of the chassis 43 by a lens mount 44, and an imaging surface of the CCD sensor 42 is disposed so as to face the emitting portion of the lens 41.

  The CCD sensor 42 is mounted on a CCD mounting board 50, the CCD mounting board 50 is fixed to a support plate 60, and the support plate 60 is supported on the chassis 43 by a suspension mechanism or a pulling mechanism using a spring. Since the suspension mechanism and the traction mechanism are not the main points of the present invention, they will not be described in detail. Hereinafter, the shape of each component will be described mainly with reference to FIG.

  The support plate 60 is formed by press-molding a sheet metal, is horizontally long, has a substantially rectangular shape, and is supported vertically with respect to the chassis 43. A bracket 61 for attaching to the suspension device and a hook 62 for engaging the tension coil spring of the traction device protrude from one surface of the support plate. A pair of brackets 61 is provided at both left and right ends of the support plate 60, and a pair of hooks 62 is provided at a position inside the bracket 61. Bending edges 63 and 64 are formed on the upper and lower sides of the support plate 60. The bending direction of the bending edges 63 and 64 is the same as the direction in which the bracket 61 protrudes. Notches 63 a and 64 a for engaging the elastic member 70 are formed at the centers of the bent edges 63 and 64.

  In addition to this, two screw holes 65 into which the screws 80 are screwed are formed in the support plate 60 at intervals on the left and right. A through hole 66 through which the lead 42 a of the CCD sensor 42 passes is formed between the two screw holes 65. Since the CCD sensor 42 is arranged with the imaging surface vertical, the leads 42a protrude from the upper and lower edges one row at a time. Correspondingly, the through-hole 66 has two elongated holes that pass through the leads 42a one by one, and are arranged in parallel in the vertical direction. Instead of providing one large through hole, the area of the through hole 66 can be suppressed by providing two smaller elongated holes, and the bridge portion 67 exists between the elongated holes, so that the strength of the support plate 60 can be reduced. Does not drop so much. The bridge portion 67 also serves as a receiving member for receiving the CCD mounting substrate 50 when the elastic member 70 presses the CCD mounting substrate 50 toward the support plate 60 as will be described later.

  The CCD sensor 42 and the CCD mounting substrate 50 are arranged so as to sandwich the support plate 60. The CCD sensor 42 is disposed on the side facing the lens 12, and the CCD mounting substrate 50 is disposed on the opposite side. In the CCD mounting substrate 50, through holes 51 into which the leads 42a of the CCD sensor 42 are inserted are formed by the number of the leads 42a, and through holes 52 through which the screws 80 are passed are formed one by one on the left and right. In order to absorb manufacturing errors of parts, one of the through holes 52 is a horizontally long slot. Needless to say, the CCD mounting board 50 is a printed wiring board, a circuit pattern is formed on the surface, and predetermined parts are mounted at predetermined positions.

  As described above, since the CCD mounting substrate 50 has a circuit pattern on the surface, a short circuit occurs when directly contacting the sheet metal support plate 60. Therefore, the insulating member 90 is sandwiched between the CCD mounting substrate 50 and the support plate 60. The insulating member 90 has a sheet shape, and is punched into substantially the same outer shape as the support plate 60, and a through hole 91 corresponding to the screw hole 65 and a through hole 92 corresponding to the through hole 66 are formed.

  The elastic member 70 is a metal thin plate used as a leaf spring, for example, a spring steel or phosphor bronze thin plate formed into a predetermined shape by press working, and is disposed on the outermost side as viewed from the side where the lens 12 is located. The At the upper and lower edges of the elastic member 70, arms 71 and 72 that hold the bent edges 63 and 64 of the support plate 60 beyond the upper and lower edges of the CCD mounting substrate 50 and the insulating member 90 are formed. The arms 71 and 72 are formed with constricted portions 71a and 72a that fit into the notches 63a and 64a of the bent edges 63 and 64, respectively. For this reason, after the arms 71 and 72 hold the bent edges 63 and 64, the elastic member 70 does not shift left and right.

  The elastic member 70 is formed with a protrusion 73 that presses the CCD mounting substrate 50 toward the support plate 60. The protrusion 73 has a ridge having a mountain-shaped cross section, and extends horizontally at a height corresponding to the bridge portion 67 of the support plate 60.

  The procedure for attaching the CCD sensor 42 is as follows. First, the insulating member 90 and the CCD mounting substrate 50 are overlapped on the support plate 60, and the screws 80 are screwed into the screw holes 65 through the through holes 52 and 91, and tightened firmly. Thereafter, the lead 42a of the CCD sensor 42 is inserted into the through hole 51 of the CCD mounting substrate 50 through the through holes 66 and 92, and soldering is performed. Next, the arms 71 and 72 of the elastic member 70 are engaged with the bent edges 63 and 64 of the support plate 60 from behind the CCD mounting substrate 50. Then, the protrusion 73 of the elastic member 70 presses the CCD mounting substrate 50 toward the support plate 60, particularly toward the bridge portion 67. The support plate 60 that has supported all the components related to the attachment of the CCD sensor 42 in this way is attached to the chassis 43 using the above-described suspension device or traction device.

  By appropriately designing the material, thickness, size, shape, etc. of the elastic member 70, the CCD mounting substrate 50 is strongly pressed against the support plate 60, and even if the CCD mounting substrate 50 warps due to temperature change, it is pressed down. Thus, it can be prevented from leaving the support plate 60. As a result, the position of the CCD sensor 42 with respect to the lens 12 does not move, and image deterioration can be prevented. Further, since there is no relative movement between the CCD sensor 42 and the CCD mounting substrate 50, the electrical connection of the lead 42a is not impaired.

  Of the components mounted on the CCD mounting substrate 50, the driver element of the CCD sensor 42 is mounted at a position farther than the screw 80 when viewed from the center of the CCD mounting substrate 50. By doing so, it is less likely that the heat generated by the driver element causes the mounting portion of the CCD sensor 42 to be thermally deformed and the position of the CCD sensor 42 is distorted.

  FIG. 7 shows comparison data examined for focus. Focus is expressed in units of “points”, and the better the focus is, the smaller the value. When the elastic member of the present invention is used, the numerical value is improved from the conventional structure that does not use the elastic member, and it is further accompanied by the movement of the driver element (moving to a place farther from the mounting screw as viewed from the center of the CCD mounting board). The numerical value improved.

  Although the embodiments of the present invention have been described above, various modifications can be made without departing from the spirit of the invention.

  The present invention can be widely used in image reading apparatuses such as digital copying machines, facsimile machines, and image scanners.

Schematic partial cross-sectional view of image forming apparatus Perspective view of image reading apparatus The perspective view which looked at the image reading apparatus from the direction different from FIG. Perspective view of the CCD mounting substrate fixed to the support plate The perspective view which looked at what fixed the CCD mounting substrate to the support plate from the direction different from FIG. Disassembled perspective view of components Comparison data table for focusing

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 40 Image reader 43 Chassis 41 Lens 42 CCD sensor 42a Lead 50 CCD mounting board 60 Support plate 66 Through hole 70 Elastic member 71, 72 Arm 73 Protrusion part

Claims (4)

In an image reading apparatus that converges reflected light from a document surface on a CCD sensor by a lens,
A through hole formed in the support plate and the insulating member, the CCD sensor is disposed on one side of the support plate, and the CCD mounting substrate is disposed on the opposite side with the insulating member interposed therebetween, and the CCD mounting substrate is fixed to the support plate. Through which the lead of the CCD sensor is inserted into the CCD mounting substrate, and an elastic member having a pair of arms holding the edge of the supporting plate is engaged with the supporting plate from the back of the CCD mounting substrate . The image reading apparatus is characterized in that each of the arms fits into a notch formed on the edge of the support plate, and the CCD mounting substrate is pressed against the support plate by a protrusion formed on the elastic member.   2. The image reading apparatus according to claim 1, wherein the through-hole formed in the support plate is formed by arranging two long holes through which the leads of the CCD sensor pass one by one in parallel. The CCD mounting substrate is fixed to the support plate with a plurality of screws,
3. The image reading apparatus according to claim 1 , wherein the driver element of the CCD sensor is mounted at a position farther from the center of the CCD mounting substrate than the screw .   An image forming apparatus comprising the image reading apparatus according to claim 1.

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