Image reading device and image forming device

Abstract

To provide an image reading device that can reduce deviation of an imaging position due to deformation of a substrate on which a solid-state image sensor is mounted.SOLUTION: An image reading device comprises: a solid-state image sensor 61 that converts reflected light reflected on a document into an electric signal; a substrate 71 that has the solid-state image sensor 61 mounted on one face; a support member 81 that is provided on the one face of the substrate 71 and determines the position of the solid-state image sensor 61; and a reinforcement member 91 that is provided on the other face of the substrate 71 to overlap the solid-state image sensor 61. The coefficient of linear expansion of the reinforcement member 91 is smaller than that of the substrate 71 and the same as that of the support member 91. The substrate 71 is fixed while being sandwiched between the reinforcement member 91 and the support member 81 on the outside of the ends of the solid-state image sensor 61.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an image reading device having a solid-state image sensor that converts light reflected from a document into an electrical signal, and an image forming apparatus having an image reading device. [Background technology]

[0002] In an image reading device that optically reads an original, light emitted from a light source is irradiated onto the original, the light reflected from the original is focused by an imaging lens onto a solid-state image sensor such as a CCD sensor, and the focused optical image is converted into an electrical signal to read the original.

[0003] The temperature around the solid-state imaging element may rise due to heat generated by the solid-state imaging element itself or the illumination lamp, and the heat may cause the circuit board on which the solid-state imaging element is mounted to deform. If the circuit board deforms in this way, the imaging position of the reflected light by the imaging lens on the solid-state imaging element may shift.

[0004] Generally, a CCD sensor is mounted on one surface of a substrate. A support plate for positioning the substrate is provided on one surface of the substrate. Patent Document 1 describes an image reading device having an elastic member provided on the other surface of the substrate. The elastic member has a pair of arms that engage with the support plate and the substrate, and a protrusion that presses the substrate against the support plate. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2009-278182 A Summary of the Invention [Problem to be solved by the invention]

[0006] The elastic member described in the above Patent Document 1 engages the substrate and the support plate with a pair of arms, and further presses the substrate against the support plate with a protrusion, thereby suppressing warping of the substrate, etc. However, since the elastic member itself is easily deformed in response to deformation of the substrate, there is a problem in that deformation of the substrate cannot be sufficiently suppressed.

[0007] SUMMARY OF THE PRESENT DISCLOSURE In consideration of the above circumstances, it is an object of the present invention to provide an image reading device and an image forming device that can reduce deviations in the imaging position caused by deformation of a board on which a solid-state image sensor is mounted. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, the image reading device of the present invention comprises a solid-state imaging element that converts light reflected from a document into an electrical signal, a substrate on one side of which the solid-state imaging element is mounted, a support member provided on the one side of the substrate for positioning the solid-state imaging element, and a reinforcing member provided on the other side of the substrate so as to overlap the solid-state imaging element, wherein the linear expansion coefficient of the reinforcing member is smaller than that of the substrate and is the same as that of the support member, and the substrate is fixed by being sandwiched between the reinforcing member and the support member outside the end of the solid-state imaging element.

[0009] In the image reading device of the present invention, the reinforcing member and the supporting member may be formed of the same material.

[0010] In the image reading device of the present invention, the solid-state imaging element may have a horizontally elongated rectangular planar shape, and the substrate may be fixed by being sandwiched between the reinforcing member and the supporting member on the outside of the longitudinal end of the solid-state imaging element.

[0011] In the image reading device of the present invention, the reinforcing member may be a plate having the same planar shape as the solid-state imaging element, and may have a bent piece bent at a substantially right angle from a long side.

[0012] An image forming apparatus according to the present invention includes the image reading device and an image forming section that forms an image on a sheet based on image data of a document read by the image reading device. Effect of the Invention

[0013] According to the present invention, deformation of the substrate when the temperature of the substrate increases can be suppressed, so that even when a solid-state imaging element is mounted on the substrate, the imaging position on the solid-state imaging element is less likely to shift. [Brief description of the drawings]

[0014] [Figure 1] 1 is a front view showing a schematic internal structure of an image forming apparatus according to an embodiment of the present invention; [Diagram 2] 1 is a front view showing a schematic internal structure of an image reading device according to an embodiment of the present invention; [Diagram 3] 1 is a perspective view, seen from the front side, of a substrate on which a solid-state imaging element is mounted in an image reading device according to an embodiment of the present invention. [Figure 4] 1 is a perspective view of a substrate on which a solid-state imaging element is mounted, as viewed from the back side, in an image reading device according to an embodiment of the present invention; [Diagram 5] 1 is a cross-sectional view showing a substrate on which a solid-state imaging element is mounted in an image forming apparatus according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] An image reading apparatus and an image forming apparatus according to an embodiment of the present invention will now be described with reference to the drawings.

[0016] First, the image forming apparatus will be described with reference to Fig. 1. Fig. 1 is a front view showing a schematic internal configuration of the image forming apparatus. In the following description, the front side of the paper in Fig. 1 is the front side (front side) of the image forming apparatus. L and R in each figure respectively indicate the left and right sides of the image forming apparatus.

[0017] As shown in FIG. 1, the image forming apparatus 1 includes an image forming unit 3 that forms an image on a sheet, and an image reading unit 5 that is disposed above the image forming unit 3 and reads the image (original document) formed by the image forming unit 3.

[0018] The image forming unit 3 includes a plurality of paper feed cassettes 11, a plurality of paper feed devices 13 that feed sheets from the plurality of paper feed cassettes 11, a toner image forming unit 15 that forms a toner image on the sheet, a fixing unit 17 that fixes the toner image on the sheet, and a discharge unit 19 that discharges the sheet. The image forming unit 3 also includes a discharge tray 21 formed below the discharge unit 19. The image forming unit 3 also includes a transport path 23 along which the sheet is transported from each paper feed device 13 through the toner image forming unit 15 and the fixing unit 17 toward the discharge unit 19.

[0019] A sheet fed by a corresponding paper feed device 13 from any of the paper feed cassettes 11 is transported along a transport path 23 to a toner image forming unit 15. The toner image forming unit 15 forms a toner image on the sheet based on the image read by the image reading unit 5. The sheet on which the toner image has been formed is transported along the transport path 23 to a fixing unit 17. The fixing unit 17 fixes the toner image on the sheet. The sheet is then discharged from a discharge unit 19 and stacked on a discharge tray 21.

[0020] Next, the image reading unit 5 will be described with reference to Figures 1 and 2. Figure 2 is a front view showing a schematic internal configuration of the reading unit of the image reading unit.

[0021] As shown in FIG. 1, the image reading unit 5 includes a reading unit 31 that reads an image of a document, and a transport unit 33 that is disposed above the reading unit 31 and transports the document to the reading unit 31.

[0022] 2, the reading unit 31 includes a contact glass 41 on which an original D can be placed, and a scanner unit 43 disposed below the contact glass 41 and configured to read an image of the original D. The reading unit 31 is an example of an image reading device of the present invention.

[0023] The scanner section 43 includes a first carriage 51 and a second carriage 53 which move in conjunction with each other in a predetermined direction (left-right direction), and an imaging unit 55 which is fixed at a predetermined position.

[0024] The first carriage 51 houses a light source 51a and a first mirror 51b. The first carriage 51 moves from a home position below the left end of the contact glass 41 to the right below the contact glass 41. The second carriage 53 houses second and third mirrors 53a and 53b. The second carriage 53 moves from a home position to the left of the home position of the first carriage 51 to the right below the first carriage 51.

[0025] The imaging unit 55 includes a CCD sensor 61, an imaging lens 63 that forms an optical image on the CCD sensor 61, and a housing 65 that accommodates the CCD sensor 61 and the imaging lens 63. The CCD sensor 61 is an example of a solid-state imaging element of the present invention. The CCD sensor 61 has a horizontally long rectangular shape and has a number of imaging elements arranged in the longitudinal direction. The imaging unit 55 is fixed below the right end of the contact glass 41 at the same height as the second carriage 53, with the CCD sensor 61 facing the second carriage 53.

[0026] The transport unit 33 (see FIG. 1) feeds the documents placed on the document tray one by one and transports them to a reading position. The reading position is a position where light is irradiated from the light source 51a of the first carriage 51 when the first carriage 51 and the second carriage 53 of the scanner unit 43 are stopped at their home positions. The transport unit 33 is vertically rotatable around a support shaft provided at the rear end of the reading unit 31.

[0027] Next, the reading operation by the image reading unit 5 will be described. When reading the document D (see FIG. 2) placed on the contact glass 41, the conveying unit 33 is rotated upward to expose the contact glass 41, and the document D is placed on the contact glass 41, and then the conveying unit 33 is rotated downward to fix the document D. Thereafter, the first carriage 51 moves rightward from the home position at a predetermined speed, and the second carriage 53 moves rightward from the home position at a speed half that of the first carriage 51. As a result, light is irradiated from the light source 51a of the first carriage 51 onto the entire surface of the document D. The light reflected by the document is reflected leftward by the first mirror 51b, and further reflected by the second and third mirrors 53a and 53b of the second carriage 53, and is imaged on the CCD sensor 65 by the imaging lens 63. The formed optical image is converted into an electric signal to form image data.

[0028] When reading a document transported by the transport unit 33, the transport unit 33 is rotated downward and the document is placed on the document tray. The first carriage 51 and the second carriage 53 of the reading unit 31 are each stopped at their home positions. The transport unit 33 transports the placed document one by one to the reading position. When the document passes the reading position, light is irradiated from the light source 51a of the first carriage 51. The light reflected by the document is reflected by the first mirror 51b of the first carriage 51, and is further reflected by the second and third mirrors 53a and 53b of the second carriage 53, and is imaged on the CCD sensor 61 by the imaging lens 63.

[0029] Next, the CCD sensor 61 will be described with reference to Fig. 3 to Fig. 5. Fig. 3 is a perspective view of the board on which the CCD sensor is mounted, seen from the front surface (left surface), Fig. 4 is a perspective view of the board on which the CCD sensor is mounted, seen from the back surface (right surface), and Fig. 5 is a cross-sectional view of the board on which the CCD sensor is mounted.

[0030] The CCD sensor 61 is mounted on the front surface of the substrate 71. As described above, the CCD sensor 61 has a horizontally long rectangular shape, and the substrate 71 also has a horizontally long rectangular shape. The terminals 61a (leads) of the CCD sensor 61 do not penetrate the substrate 71, but are soldered to approximately half of the substrate in the longitudinal direction. A connector 73 and the like are also mounted on the front surface of the substrate 71. The substrate 71 is formed of, for example, phenolic resin or epoxy resin.

[0031] A support member 81 for positioning the CCD sensor 61 in the housing 65 is provided on the front surface of the substrate 71. In addition, a reinforcing member 91 is provided on the back surface of the substrate 71.

[0032] 3, the support member 81 has a flat portion 83 in which an opening 83a is formed to expose the mounted CCD sensor 61. A plurality of support pieces 85 fixed to the housing 65 are formed around the flat portion 83. The support pieces 85 are bent at right angles to the flat portion 83. A support hole is formed in a part of the support piece 85. The support member 81 is made of a material (e.g., an iron plate) having a smaller linear expansion coefficient than the substrate 71.

[0033] 4, the reinforcing member 91 is a horizontally long rectangular plate piece, with a longitudinal length longer than the longitudinal length of the CCD sensor 61 and a lateral length equal to the lateral length of the CCD sensor 61. At least one long side of the reinforcing member 91 is formed with a bent piece 93 bent at a substantially right angle. The reinforcing member 91 is made of a material (e.g., an iron plate) having a smaller linear expansion coefficient than the substrate 71. The reinforcing member 91 is preferably made of the same material as the support member 81.

[0034] A recess 91a is formed on the other long side of the reinforcing member 91. Electrical elements and the like can be mounted on the rear surface of the substrate 71 through this recess 91a.

[0035] The support member 81 and the reinforcing member 91 are attached to the substrate 71 with a number of screws S (three in this example). The support member 81 is positioned on the front surface of the substrate 71 so that the CCD sensor 61 is exposed from the opening 83a, as shown in Fig. 3, and the flat portion 83 is in close contact with the front surface. The reinforcing member 91 is positioned on the back surface of the substrate 71 so as to overlap the CCD sensor 61, as shown in Fig. 4.

[0036] Both ends of the reinforcing member 91 in the longitudinal direction are fixed to the substrate 71 and the support member 81 with screws S from the back side of the substrate 71. In this way, the reinforcing member 91 is fixed to the substrate 71 and the support member 81 on both outer sides in the longitudinal direction of the CCD sensor 61. In other words, the substrate 71 is sandwiched and fixed between the support member 81 and the reinforcing member 91 on both outer sides in the longitudinal direction of the CCD sensor 61. Furthermore, the support member 81 and the substrate 71 are fixed with screws S from the back side of the substrate 71 at a position far from the two screws S.

[0037] When the reinforcing member 91 is made of metal, an insulating member is sandwiched between the substrate 71 and the reinforcing member 91. This makes it possible to prevent electrical continuity between a metal pattern formed on the rear surface of the substrate 71 and the reinforcing member 91. In this case, it is preferable to sandwich a conductive member between the insulating member and the reinforcing member 91, ground the conductive member, and ground the reinforcing member 91 via the conductive member.

[0038] In the imaging unit 55 of the reading section 31 having the above configuration, when the temperature of the substrate 71 rises due to heat emitted from the light source 51a or heat generated by the CCD sensor 61, the substrate 71 tends to deform so that the back surface becomes convex. However, the substrate 71 is fixed by being sandwiched between a support member 81 and a reinforcing member 91 on the outside of both ends in the longitudinal direction of the CCD sensor 61. The support member 81 and the reinforcing member 91 are made of a material with a smaller linear expansion coefficient than the substrate 71, and the degree of deformation due to heat is smaller than that of the substrate, so deformation of the substrate 71 can be suppressed.

[0039] As described above, according to the present invention, deformation of the substrate 71 when the temperature of the substrate 71 rises can be suppressed, so that even if the CCD sensor 61 is mounted on the substrate 71, the imaging position on the CCD sensor 61 is less likely to shift. Therefore, the image of the document can be accurately read by the CCD sensor 61.

[0040] In addition, since the reinforcing member 91 and the supporting member 81 have the same linear expansion coefficient, even if the temperature rises, the front and back surfaces of the substrate 71 can support the substrate 71 with equal force, making it difficult for the substrate 71 to bend. Note that the reinforcing member 91 and the supporting member 81 do not necessarily have to have the same linear expansion coefficient, and there may be some difference as long as it is smaller than the linear expansion coefficient of the substrate 71. In addition, the reinforcing member 91 and the supporting member 81 do not necessarily have to be made of the same material.

[0041] Furthermore, since the reinforcing member 91 has a bent piece 93 formed therein, it is possible to increase the strength of the reinforcing member 91. It is preferable that the bent piece 93 is formed at a position overlapping the CCD sensor 61. In this case, it is possible to further reduce the deformation of the substrate 71 between both outer sides of both longitudinal ends of the CCD sensor 61.

[0042] Furthermore, when the substrate 71 is deformed, the amount of misalignment between both ends of the CCD sensor 61 in the longitudinal direction becomes greater than the amount of misalignment between both ends in the lateral direction. Therefore, by sandwiching and fixing the substrate 71 between the support member 81 and the reinforcing member 91 on the outside of both ends of the CCD sensor 61 in the longitudinal direction, the misalignment between both ends in the longitudinal direction when the substrate 71 is deformed can be reduced. Note that the length of the reinforcing member 91 in the lateral direction (vertical direction) may be made longer than the length of the CCD sensor 61 in the lateral direction (vertical direction), and the reinforcing member 91 may be fixed to the substrate 71 and the support member 81 with screws on the outside of the lateral direction of the CCD sensor 61.

[0043] Although the present invention has been described with reference to specific embodiments, the present invention is not limited to the above embodiments, and those skilled in the art may modify the above embodiments without departing from the scope and spirit of the present invention. [Explanation of symbols]

[0044] 1. Image forming device 3. Image forming section 31 Reading unit (image reading device) 61 CCD sensor (solid-state image sensor) 71 Substrate 81 Support member 91 Reinforcement members 93 Bending piece

Claims

1. a solid-state image sensor having a horizontally elongated rectangular planar shape for converting light reflected from a document into an electrical signal; a substrate having the solid-state imaging element mounted on one surface thereof; a support member provided on the one surface of the substrate for positioning the solid-state imaging element; a reinforcing member having a horizontally elongated rectangular planar shape provided on the other surface of the substrate so as to overlap the solid-state imaging element; the reinforcing member has a bent piece bent at a right angle from a long side, and has a linear expansion coefficient smaller than that of the substrate and equal to that of the supporting member; An image reading device characterized in that the substrate is fixed between the reinforcing member and the support member outside the end of the solid-state imaging element, and the folded piece of the reinforcing member overlaps with the solid-state imaging element.

2. 2. The image reading device according to claim 1, wherein the reinforcing member and the supporting member are made of the same material.

3. An image reading device as described in claim 1 or 2, characterized in that the substrate is fixed by being sandwiched between the reinforcing member and the support member outside the longitudinal end of the solid-state imaging element.

4. An image reading device according to any one of claims 1 to 3, an image forming section that forms an image on a sheet based on image data of the document read by the image reading device.

5. An image forming apparatus as described in Claim 3, characterized in that both longitudinal ends of the reinforcing member are fixed to the substrate and the support member with screws from the other side of the substrate.

Images