Reading device and image forming device

Abstract

To provide a reading device that can prevent the occurrence of color unevenness in a main scanning direction of a read image compared with a case where an optical filter is arranged in parallel with an end face of a light guide, and an image forming apparatus.SOLUTION: A reading device comprises: a light source; a film-like optical filter that inhibits, of the rays of light from the light source, light with a predetermined wavelength; and a cylindrical light guide that guides light passing through the optical filter and incident on one end face to the other end face, and irradiates a body to be irradiated with light emitted from a side face. Diffusion patterns for diffusing the light are arranged on the side face of the light guide on the opposite side not facing the body to be irradiated. The optical filter is arranged at a position facing the end face of the light guide, and is arranged obliquely to the end face of the light guide.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a reading device and an image forming device. [Background technology]

[0002] Patent Document 1 discloses an image sensor that includes a light source, a phosphor that emits white light using light from the light source, an optical filter that blocks light from the phosphor that has wavelengths longer than those in a predetermined visible light region, a columnar light guide that transmits light that passes through the optical filter and enters one end to the other end and irradiates the illuminated object with light that exits from its side, and a sensor IC that receives light reflected from the illuminated object and converts it into an electrical signal.

[0003] Patent document 2 discloses an image sensor unit comprising a light source, an imaging element that forms an image of reflected light from an illuminated object, and a sensor substrate on which a photoelectric conversion element that converts the reflected light formed by the imaging element into an electrical signal is mounted, wherein a resin containing an infrared absorbing dye is provided in the light path between the light emitting surface of the light source and the light receiving section of the photoelectric conversion element.

[0004] Patent Document 3 discloses an image reading device that includes a light guide extending in the main scanning direction, which receives light from a light source at its end face in the main scanning direction and emits light toward a reading object moving relatively in the sub-scanning direction, an optical filter that is provided between the end face in the main scanning direction of the light guide and the light source and blocks or attenuates light of a specific wavelength from the light emitted from the light source, a lens body that converges the light reflected from the reading object and forms an image on a photoreceptor that converts the reflected light into an electrical signal, and a lens holder that holds the light guide, the optical filter, and the lens body, wherein the lens holder includes a first positioning unit that determines the position of the light guide in a height direction perpendicular to the main scanning direction and the sub-scanning direction and the position in the sub-scanning direction, and a second positioning unit that determines the position of the optical filter in a height direction perpendicular to the main scanning direction and the sub-scanning direction and the position in the sub-scanning direction. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-028617 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-239031 [Patent Document 3] Patent No. 6732154 Summary of the Invention [Problem to be solved by the invention]

[0006] When an optical filter blocks infrared light from a light source, the angle dependency of the optical filter also blocks some red light in the red light region depending on the angle of light emission from the light source to the optical filter. Therefore, when light is emitted from a light source at a high inclination angle relative to an optical filter arranged parallel to the end face of a light guide, more red light is blocked than when light is emitted at a low inclination angle. As a result, compared to the central portion of the light guide in the longitudinal direction where light emitted from a light source at a low inclination angle passes through the optical filter and reaches, there is insufficient red light at the end portions of the light guide in the longitudinal direction where light emitted at a high inclination angle passes through the optical filter, resulting in color unevenness in the main scanning direction of the scanned image.

[0007] The present invention aims to provide a reading device and an image forming device that can prevent color unevenness in the main scanning direction of a read image, compared to when an optical filter is arranged parallel to the end face of a light guide. [Means for solving the problem]

[0008] The reading device according to the first aspect comprises a light source, a film-like optical filter that blocks light of a predetermined wavelength from the light source, and a cylindrical light guide that guides light that passes through the optical filter and enters one end face to the other end face and irradiates the light that exits from the side face onto an illuminated body, and a diffusion pattern that diffuses the light is arranged on the side of the light guide opposite the illuminated body, and the optical filter is arranged in a position facing the end face of the light guide and at an angle to the end face of the light guide.

[0009] In the reading device of the second aspect, the optical filter is arranged at an angle so that the position on the end face of the light guide facing the diffusion pattern is farther from the light guide than the position facing the illuminated body.

[0010] In the reading device of the third aspect, the optical filter is positioned so that the angle between the light from the light source and the normal to the plane of the optical filter is smaller on the side of the end face of the light guide facing the diffusion pattern than on the side facing the illuminated body.

[0011] In the reading device according to the fourth aspect, two light guides are provided in parallel, a light source is disposed for each light guide, and one optical filter is disposed on one of the end faces of the two light guides.

[0012] In the reading device according to a fifth aspect, two of the light guides are provided in parallel, the light source is disposed for each of the light guides, and the optical filter is disposed for each of the light guides.

[0013] In the reading device according to a sixth aspect, the optical filters are disposed on the one end surface and the other end surface of the light guide.

[0014] In the reading device of the seventh aspect, the diffusion pattern is arranged on the side of the two light guides opposite to the illuminated body and away from the other light guides, and the optical filter is arranged diagonally so that the position on the end face of the light guide facing the diffusion pattern and away from the other optical filters is farther from the light guide than the position facing the illuminated body.

[0015] An image forming apparatus according to an eighth aspect includes the reading device according to any one of the first to seventh aspects. [Effects of the Invention]

[0016] The first aspect has the advantage that it is possible to prevent color unevenness in the main scanning direction of the read image, compared to when an optical filter is arranged parallel to the end face of the light guide.

[0017] The second aspect has the advantage of being able to prevent color unevenness in the main scanning direction of the read image, compared to when the optical filter is positioned at an angle so that the position not facing the diffusion pattern is away from the light guide.

[0018] According to the third aspect, the optical filter has the advantage of being able to prevent color unevenness in the main scanning direction of the read image, compared to when the optical filter is positioned so that the angle between the light from the light source and the normal to the plane of the optical filter is larger on the side of the end face of the light guide facing the diffusion pattern than on the side facing the irradiated body.

[0019] According to the fourth aspect, there is an effect that the assembly of the reading device can be made easier than when an optical filter is provided for each light guide.

[0020] According to the fifth aspect, there is an effect that the inclination of each optical filter can be adjusted for each light guide.

[0021] The sixth aspect has the advantage that it is possible to prevent color unevenness in the main scanning direction of the read image, compared to when an optical filter is disposed on one of the end faces.

[0022] According to the seventh aspect, there is an effect that each optical filter can be disposed for each light guide at an angle toward the diffusion pattern side.

[0023] According to the eighth aspect, it is possible to provide an image forming apparatus that can prevent color unevenness from occurring in the main scanning direction of a read image, compared to when an optical filter is arranged parallel to the end face of a light guide. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a schematic configuration diagram showing an image forming apparatus according to a first embodiment of the present invention. [Figure 2] 1 is a configuration diagram showing an image reading unit of an image forming apparatus according to a first embodiment of the present invention. [Figure 3] 1 is a perspective view showing an image reading device according to a first embodiment of the present invention. [Figure 4] 1 is an exploded perspective view showing an image reading device according to a first embodiment of the present invention. [Figure 5] 10B is a cross-sectional view (cross-section taken along line 10B-10B in FIG. 6) showing the image reading device according to the first embodiment of the present invention. [Figure 6] 10A is a cross-sectional view (cross-section taken along line 10A-10A in FIG. 5) showing an image reading device according to a first embodiment of the present invention. [Figure 7] FIG. 2 is an explanatory diagram for explaining a diffusion pattern and light emitted from a light emitting element according to the first embodiment of the present invention. [Figure 8] FIG. 2 is an explanatory diagram illustrating a state in which the optical filter according to the first embodiment of the present invention is disposed obliquely with respect to the end face of the light guide. [Figure 9] FIG. 2 is a diagram showing the spectral characteristics of the light receiving element according to the first embodiment of the present invention. [Figure 10]FIG. 2 is a diagram showing the spectral characteristics of the light-emitting element according to the first embodiment of the present invention. [Figure 11] FIG. 2 is a diagram showing the spectral characteristics of the optical filter according to the first embodiment of the present invention. [Figure 12] FIG. 2 is a diagram showing the spectral characteristics of the image reading device according to the first embodiment of the present invention. [Figure 13] FIG. 10 is a diagram showing the relative value of the red output distribution when the angle of incidence is changed relative to when the optical filter according to the first embodiment of the present invention is not provided. [Figure 14] FIG. 10 is an explanatory diagram for explaining the arrangement of a light guide and an optical filter according to a second embodiment of the present invention. [Figure 15] FIG. 10 is an explanatory diagram for explaining the arrangement of a light guide and an optical filter according to a third embodiment of the present invention. [Figure 16] FIG. 10 is an explanatory diagram for explaining the arrangement of a light guide and an optical filter according to a fourth embodiment of the present invention. [Figure 17] FIG. 10 is an explanatory diagram for explaining the arrangement of a light guide and an optical filter according to a fifth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0025] (First embodiment) An example of an embodiment of the present disclosure will be described below with reference to the drawings. In each drawing, identical or equivalent components and parts are designated by the same reference numerals. The dimensional proportions in the drawings are exaggerated for the sake of explanation and may differ from the actual proportions. In the drawing, arrow H indicates the up-down direction (vertical direction) of the device, arrow W indicates the width direction (horizontal direction) of the device, and arrow D indicates the depth direction (horizontal direction) of the device.

[0026] (Overall composition) As shown in FIG. 1, the image forming apparatus 10 according to the first embodiment is provided with, from bottom to top in the vertical direction (direction of arrow H), a storage section 14 in which a sheet material P as a recording medium is stored, a transport section 16 that transports the sheet material P stored in the storage section 14, an image forming section 20 that forms an image on the sheet material P transported from the storage section 14 by the transport section 16, and an image reading section 60 that reads an image formed on a document G.

[0027] (Storage section) The storage unit 14 is provided with a storage member 26 that can be pulled out from the housing 10A of the image forming apparatus 10 toward the front in the device depth direction, and sheet materials P are stacked on this storage member 26. Furthermore, the storage unit 14 is provided with a delivery roll 30 that sends out the topmost sheet material P stacked on the storage member 26 to a conveying path 28 that constitutes the conveying unit 16.

[0028] (Transportation section) The conveying section 16 is provided with a plurality of conveying rolls 32 that convey the sheet material P along the conveying path .

[0029] (Image forming section) The image forming section 20 is provided with four image forming units 18Y, 18M, 18C, and 18K for yellow (Y), magenta (M), cyan (C), and black (K). In the following description, when there is no need to distinguish between Y, M, C, and K, the terms Y, M, C, and K may be omitted.

[0030] The image forming units 18 for each color are detachably attached to the housing 10A. Each image forming unit 18 for each color includes an image carrier 36, a charging roll 38 that charges the surface of the image carrier 36, and an exposure device 42 that irradiates the charged image carrier 36 with exposure light. Each image forming unit 18 for each color also includes a developing device 40 that develops the electrostatic latent image formed by the exposure device 42 exposing the charged image carrier 36 to light, thereby visualizing the electrostatic latent image as a toner image.

[0031] 1, and a primary transfer roll 44 that transfers the toner images formed by the image forming units 18 of each color onto the transfer belt 22. The image forming unit 20 also includes a secondary transfer roll 46 that transfers the toner images transferred onto the transfer belt 22 onto a sheet member P, and a fixing device 50 that applies heat and pressure to the sheet member P onto which the toner images have been transferred to fix the toner images onto the sheet member P.

[0032] (Image reading unit) 2, the image reading unit 60 includes a first transparent plate 62 (so-called platen glass) on which a sheet of original G is placed when the image of the sheet of original G is read, and a second transparent plate 72 disposed on one side of the first transparent plate 62 in the device width direction (left side in FIG. 2). The first transparent plate 62 and the second transparent plate 72 are fitted into the upper part of a housing 60A of the image reading unit 60.

[0033] An opening / closing cover 66 is disposed above the first transparent plate 62 and the second transparent plate 72, and opens or closes the first transparent plate 62 and the second transparent plate 72. Inside the opening / closing cover 66, a transport device 64 (a so-called ADF device) is provided, which transports multiple sheets of original G along a transport path 70 inside the opening / closing cover 66 and passes the original G through an original reading position R above the second transparent plate 72.

[0034] An image reading device 100 is provided in the internal space 88 of the housing 60A to read an image of the document G placed on the first transparent plate 62 and an image of the document G transported to the document reading position R by the transport device 64. Here, the image reading device 100 is an example of a reading device. Furthermore, the image reading unit 60 is provided with a drive device 74 that drives the image reading device 100 in the device width direction.

[0035] As shown in FIG. 2, the drive device 74 includes a shaft 76 extending in the device width direction (the direction of movement of the image reading device 100), and a sliding member 78 attached to the underside of the housing 114 of the image reading device 100 and slidably supported on the shaft 76.

[0036] Furthermore, the drive device 74 includes a motor 80, a drive pulley 84 that is rotated by the driving force transmitted from the motor 80, a driven pulley 86 that rotates in response to the motor 80, and an endless belt 82 that is wound around the drive pulley 84 and the driven pulley 86. The drive pulley 84 is attached to one end of the shaft 76, and the driven pulley 86 is attached to the other end of the shaft 76.

[0037] The image reading device 100 will be described in detail later.

[0038] (Action of image forming device) In the image forming apparatus 10, an image is formed as follows.

[0039] First, the image reading unit 60 reads an image of the original G. Specifically, when reading an image of the original G being transported by the transport device 64, the driving force of the motor (not shown) is transmitted to the image reading device 100 via the endless belt 82, and the image reading device 100 moves to the transport reading position on the other side in the device width direction and stops there, as shown in Fig. 2. Then, the image reading device 100 arranged at the transport reading position reads an image of the original G being transported by the transport device 64.

[0040] Furthermore, when reading an image of the original G placed on the first transparent plate 62, although not shown, the image reading device 100 moves in the device width direction along the first transparent plate 62 by the drive device 74 from the reading start position toward the reading end position while reading the image of the original G.

[0041] Next, based on the image information read by the image reading unit 60, the exposure device 42 irradiates the surface of the image carrier 36 of each color, which has been charged by the charging roll 38, with exposure light to form an electrostatic latent image (see FIG. 1).

[0042] As a result, an electrostatic latent image corresponding to the data is formed on the surface of the image carrier 36 of each color. The developing device 40 of each color then develops this electrostatic latent image, making it visible as a toner image. The toner image formed on the surface of the image carrier 36 of each color is then transferred to the transfer belt 22 by the primary transfer roll 44.

[0043] Therefore, the sheet material P sent out from the storage member 26 to the conveying path 28 by the delivery roll 30 is sent to the transfer position T where the transfer belt 22 and the secondary transfer roll 46 come into contact. At the transfer position T, the sheet material P is conveyed between the transfer belt 22 and the secondary transfer roll 46, so that the toner image on the surface of the transfer belt 22 is transferred to the sheet material P.

[0044] The toner image transferred to the sheet member P is fixed to the sheet member P by the fixing device 50. Then, the sheet member P on which the toner image has been fixed is discharged by the transport roll 32 to the outside of the housing 10A.

[0045] (Main part configuration) Next, the image reading device 100 will be described in detail.

[0046] 3 to 7, the image reading device 100 includes a light emitting device 124 that emits light toward the document G, a light receiving unit 42 that receives the light, a rod lens array 112 that guides the light to the light receiving unit 42, and a glass plate 122. The document G is an example of an irradiated object. The image reading device 100 reads the image formed on the document G using a known CIS (Contact Image Sensor) method.

[0047] (Light receiving part) The light receiving unit 42 has a light receiving substrate 102 and a plurality of light receiving elements 126 arranged in the depth direction of the device. As shown in Fig. 4, the thickness direction of the light receiving substrate 102 is the up-down direction. When viewed from above, the light receiving substrate 102 has a rectangular shape extending in the depth direction of the device, and is disposed below the housing 114. In addition, a plurality of light receiving elements 126 are formed on the upper surface of the light receiving substrate 102.

[0048] (rod lens array) Rod lens array 112 is made of a transparent material (e.g., glass), is formed in a rectangular parallelepiped shape extending in the depth direction of the device, and is housed in lens housing section 114B (described later) of the housing as shown in Fig. 5. Rod lens array 112 is configured to collect light onto light receiving element 126, the light being emitted from side surface 110B of light guide 110 (described later) and reflected from document G on which an image is formed.

[0049] (glass plate) The glass plate 122 has a thickness in the up-down direction and a rectangular shape extending in the depth direction of the device when viewed from above. As shown in Fig. 5 , the glass plate 122 is fixed to the housing 114 by a fixing means (not shown) with the edge of the glass plate 122 in contact with the step portion 115 of the housing 114, and is disposed so as to cover the top surface of the housing 114.

[0050] (Light-emitting device) Next, the light emitting device 124 will be described in detail.

[0051] 4 and 5, the light emitting device 124 has a light guide 110, an irradiation unit 103, and a housing 114 that constitutes the device main body. The light emitting device 124 has two light guides 110, which are arranged in parallel and symmetrical with respect to the center of the housing 114 in the device width direction.

[0052] (light guide) As shown in Fig. 4, the light guide 110 is formed in a cylindrical shape using a transparent material (e.g., acrylic resin), and extends with its longitudinal direction aligned with the depth direction of the device. The light guide 110 is housed in a light guide housing portion 114A (see Fig. 5) described later of a housing 114 (see Fig. 4). The light guide 110 causes light that has passed through an optical filter 130 described later and entered one end surface 110A to travel in the longitudinal direction, and irradiates light that has exited from a side surface 110B onto the document G.

[0053] 5 to 7, the light guide 110 is provided with a diffusion pattern 111 that diffuses light incident from an end surface 110A of the light guide 110 and causes it to travel in the longitudinal direction, and also emits the light toward above the rod lens array 112 (in the direction of arrow B in the drawings). As shown in FIG. 5, the diffusion pattern 111 is disposed on one of the side surfaces 110B of the light guide 110 opposite to the document G. More specifically, the diffusion pattern 111 is disposed on one of the side surfaces 110B of the two light guides 110 opposite to the document G and away from the other light guide 110. That is, the diffusion pattern 111 is not disposed directly below the light guide 110 in the device downward direction, but is disposed such that the center of the fan-shaped diffusion pattern 111 in the device width direction passes through the center of the light guide 110 and is offset toward the document reading position R. 7, the diffusion patterns 111 are provided at predetermined intervals along the longitudinal direction of the light guide 110. Here, the diffusion patterns 111 are made of, for example, solidified white paint, and diffuse the light traveling inside the light guide 110 and direct it toward the upper surface side of the light guide 110 (the document G side).

[0054] (Irradiation unit) As shown in FIG. 4, the irradiation unit 103 includes a wiring substrate 104, an element substrate 106, a light emitting element 128, and an optical filter 130.

[0055] The wiring boards 104 are so-called flexible flat cables, and a pair of them are provided as shown in Fig. 4. One wiring board 104 has a base end connected to an end of the light receiving board 102 on the far side in the device depth direction (left side in Fig. 4), and the other wiring board 104 has a base end connected to an end of the light receiving board 102 on the near side in the device depth direction (right side in Fig. 4).

[0056] The element substrate 106 is a so-called flexible printed circuit (FPC) and has a thickness direction aligned with the depth direction of the device. The element substrate 106 is a rectangular substrate when viewed from above and in the depth direction of the device, and a pair of element substrates 106 are provided as shown in FIG. 4. One element substrate 106 is connected to the leading end of one wiring substrate 104, and the other element substrate 106 is connected to the leading end of the other wiring substrate 104. LED light-emitting elements 128 (hereinafter referred to as "light-emitting elements 128") are mounted on one surface of each element substrate 106 and aligned in the width direction of the device. The light-emitting elements 128 are an example of a light source. The element substrate 106 may be flexible. For example, flexibility means that a substrate with a width of 10 mm is supported in a cantilevered state and a portion 10 mm from the supporting end is pressed from above with a force of 9.8 N, and the amount of deflection is 1 mm or more.

[0057] 5, the light emitting elements 128 are arranged on the surface of the element substrate 106 facing the light guides 110, for every two light guides 110, so as to face the end faces 110A of the light guides 110. Each light emitting element 128 emits light and irradiates the end faces 110A with light.

[0058] The optical filter 130 is disposed between the light emitting element 128 and the end surface 110A of the light guide 110, and is formed in the shape of a flat film to block light of a predetermined wavelength from the light emitting element 128. In this embodiment, the optical filter 130 is an IR Cut Filter that blocks light of a predetermined wavelength, for example, light with a wavelength greater than approximately 670 nm, such as infrared light. As shown in FIG. 5, one optical filter 130 is disposed for each of the two light guides.

[0059] 5 to 8, the optical filter 130 is disposed at a position facing the end surface 110A of the light guide 110, and is disposed at an angle relative to the end surface 110A of the light guide 110. That is, the optical filter 130 is disposed at an angle such that a position of the end surface 110A of the light guide 110 facing the diffusion pattern 111 (a lower side of the device) is farther away from the light guide 110 than a position of the end surface 110A of the light guide 110 facing the document G (a higher side of the device). More specifically, as shown in FIG. 8, the optical filter 130 is disposed such that an angle A formed between the light from the light source and a normal to the plane of the optical filter 130 on the side facing the diffusion pattern 111 is smaller than an angle B formed between the end surface 110A of the light guide 110 facing the document G.

[0060] The oblique placement of the optical filter 130 will be described in detail with reference to FIGS.

[0061] Figure 9 is a diagram illustrating an example of the spectral characteristics of the blue sensor, green sensor, and red sensor provided in each light-receiving element. The blue sensor uses blue (475 nm), green (525 nm), and red (640 nm) as predetermined reading colors. Each sensor selectively receives each color, but when reading red, nearby infrared light causes noise. In addition, the spectral sensitivity of the light-receiving section of the sensor chip 6, which has a C-MOS configuration using silicon semiconductors, also receives light on the long wavelength side, such as infrared light, as shown in the diagram.

[0062] 10 is a diagram showing the spectral characteristics of light-emitting element 128. As shown in Fig. 10, the light source made of an LED also outputs infrared light with a wavelength longer than red, and each sensor also receives infrared light with a wavelength longer than red, which affects image quality.

[0063] In order to remove such infrared light, the optical filter 130 is provided, and as shown in Fig. 11, it can be seen that the optical filter 130 has the property of cutting red light when the optical filter 130 is at 20 degrees (angle C in Fig. 8) with respect to the end face 110A of the light guide 110, compared to when the optical filter 130 is parallel to the end face 110A of the light guide 110 (angle C in Fig. 8) (so-called blue shift). Therefore, as shown in Fig. 12, there is no or very little change in the spectral characteristics of blue and green when the angle of the optical filter 130 with respect to the end face 110A of the light guide 110 is changed from 0 degrees to 20 degrees, but the spectral characteristics of red change when the angle is changed from 0 degrees to 20 degrees, and the red color is cut off.

[0064] 13 shows the relative values ​​of the red output distribution from the center (0 mm) to the ends (+150 mm, −150 mm) in the longitudinal direction of the light guide 110 for the following cases: when the optical filter 130 is not provided (no IRCF), when the optical filter 130 is provided parallel to the end face 110A of the light guide 110 (with IRCF), when the optical filter 130 is tilted by 5 degrees relative to the end face 110A of the light guide 110 (IRCF 5 degrees), and when the optical filter 130 is tilted by 10 degrees relative to the end face 110A of the light guide 110 (IRCF 10 degrees). The length of the light guide 110 used here is approximately 300 mm, as it is long enough to fit an A3 paper size (297 mm × 420 mm). In addition, when the optical filter 130 is tilted by 5 degrees with respect to the end face 110A of the light guide 110, the optical filter 130 facing the lower surface of the light guide 110 is tilted by 5 degrees so as to be away from the end face 110A of the light guide 110, based on the optical filter 130 being arranged parallel to the end face 110A of the light guide 110 (angle C in Figure 8).

[0065] 13, the red output is smallest when the optical filter 130 is provided parallel to the end surface 110A of the light guide 110 (with IRCF). Specifically, at the longitudinal center (0) of the light guide 110, the red output distribution is the same or only slightly different from when the optical filter 130 is not provided (without IRCF), but the red output distribution decreases with increasing distance from the center (0), and the output distribution is approximately -18% from around 70 mm (+70 mm, -70 mm) to the ends (+150 mm, -150 mm). Furthermore, when the optical filter 130 is tilted by 5 degrees relative to the end face 110A of the light guide 110 (IRCF 5 degrees), as with the case where the optical filter 130 is provided parallel to the end face 110A of the light guide 110 (with IRCF), the red output distribution at the longitudinal center (0) of the light guide 110 is the same as or only slightly different from the case where the optical filter 130 is not provided (without IRCF), but the red output distribution decreases with distance from the center (0), and the output distribution is approximately -14% from approximately 70 mm (+70 mm, -70 mm) to the ends (+150 mm, -150 mm). This difference in the red output distribution between the longitudinal center and ends of the light guide results in color unevenness.

[0066] On the other hand, when the optical filter 130 is tilted by 10 degrees with respect to the end face 110A of the light guide 110 (IRCF 10 degrees), the red output distribution decreases even when the optical filter 130 is disposed parallel to the end face 110A of the light guide 110 (with IRCF) or when the optical filter 130 is tilted by 5 degrees with respect to the end face 110A of the light guide 110 (IRCF 5 degrees), even when the optical filter 130 is farther from the center (0), but remains at approximately -7%. This shows that it is desirable to tilt the optical filter 130 by approximately 10 degrees with respect to the end face 110A of the light guide 110. However, this does not exclude tilting the optical filter 130 by more than 10 degrees.

[0067] (Housing) As shown in Fig. 4, the housing 114 is box-shaped and extends in the device depth direction. As shown in Fig. 5, the housing 114 is formed with a pair of light guide housing sections 114A in which the pair of light guides 110 are respectively housed, and a lens housing section 114B formed between the pair of light guide housing sections 114A and in which the rod lens array 112 is housed. Furthermore, the housing 114 is formed with a substrate housing section 114C in which the element substrate 106 and a part of the pressing member 120 are housed.

[0068] 4 and 5, a pair of light guide receiving portions 114A are formed side by side in the width direction of the device, and each light guide receiving portion 114A extends in the depth direction of the device. Furthermore, a cross section of each light guide receiving portion 114A intersecting the longitudinal direction is semicircular with an open upper portion.

[0069] 5, the lens housing portion 114B is formed between the pair of light guide housing portions 114A in the device width direction and penetrates in the up-down direction. The lens housing portion 114B is formed with a pair of protrusions 116 that support the end portions of the lower surface of the rod lens array 112 in the device width direction.

[0070] As shown in Fig. 4, a pair of substrate accommodating portions 114C are formed on the rear side and the front side in the device depth direction relative to the light guide accommodating portion 114A, and each of the substrate accommodating portions 114C penetrates in the up-down direction as shown in Fig. 6. Specifically, the substrate accommodating portions 114C are formed between the wall portions 119 at both ends in the longitudinal direction of the housing 114 and the light guide accommodating portion 114A, and a flange 118 that comes into contact with the lower end of the element substrate 106 from below is formed below the substrate accommodating portion 114C.

[0071] (Second embodiment) Next, a second embodiment will be described with reference to FIG. In the first embodiment described above, one optical filter 130 is provided on each end of the light guide 110, and one optical filter 130 is arranged for each of the two light guides 110, one on one side of the light guide 110 and the other side of the light guide 110. In contrast, in the second embodiment, two optical filters 130 are provided on each end of the light guide 110, and an optical filter 130 is arranged for each light guide 110. The following description will focus on the differences from the first embodiment described above, and descriptions of overlapping parts will be simplified or omitted.

[0072] FIG. 14 is a schematic diagram illustrating the arrangement of the light guide 110 and the optical filter 130 in this embodiment. In this embodiment, as shown in Fig. 14, one optical filter 130 is disposed on each end surface 110A of two light guides 110. With this configuration, the size of the optical filter 130 can be made smaller than when one optical filter 130 is disposed for two light guides 110. Also, the optical filter 130 is disposed at an angle, similar to the first embodiment described above (see Fig. 6).

[0073] (Third embodiment) Next, a third embodiment will be described with reference to FIG. In the second embodiment described above, the optical filter 130 is arranged at an angle so that the position on the end face 110A of the light guide 110 facing the diffusion pattern 111 (toward the bottom of the device) is farther from the light guide 110 than the position on the end face 110A facing the document G (toward the top of the device). In the third embodiment, however, the optical filter 130 is arranged at an angle so that the position on the end face 110A of the light guide 110 facing the diffusion pattern 111 and farther from the other optical filters 130 is farther from the light guide 110 than the position on the end face 110A facing the document G. The following description will focus on the differences from the second embodiment described above, and a description of overlapping parts will be simplified or omitted.

[0074] FIG. 15 is a schematic diagram illustrating the arrangement of the light guide 110 and the optical filter 130 in this embodiment. 15 , in this embodiment, the optical filter 130 is disposed obliquely so that the end surface 110A of the light guide 110 faces the diffusion pattern 111 rather than the original G, and the position farther from the other optical filters 130 is farther from the light guide 110. Specifically, the flat optical filter 130 is disposed so that the central corner 130A of the optical filter 130 is closest to the end surface 110A of the light guide 110 and the end corner 130B is farthest from the end surface 110A of the light guide 110. This allows the red component of the light emitted toward the diffusion pattern 111 to reach the diffusion pattern 111 without being cut off. The light that reaches the diffusion pattern 111 is diffused and irradiated onto the original G, enabling the original G to be read without color unevenness.

[0075] (Fourth embodiment) Next, a fourth embodiment will be described with reference to FIG. In the first to third embodiments described above, the optical filter 130 is formed as a flat plate, but in the fourth embodiment, the optical filter 130 is formed as an approximately semi-cylindrical shape with its side facing the end surface 110A of the light guide 110. The following description will focus on the differences from the first to third embodiments described above, and a description of overlapping parts will be simplified or omitted.

[0076] FIG. 16 is a schematic diagram illustrating the arrangement of the light guide 110 and the optical filter 130 in this embodiment. In this embodiment, as shown in FIG. 16 , the optical filter 130 is formed in a substantially semi-cylindrical shape, and the side surface of the substantially semi-cylindrical shape is disposed facing the end surface 110A of the light guide 110. Here, as shown in FIG. 16 , the substantially semi-cylindrical shape is formed in a curved shape such that the light emitting element 128 is located at the center of the cylinder, and the angle D between the light emitted from the light emitting element 128 to the optical filter 130 and the normal to the plane of the optical filter 130 is the same. The angle at which the light emitted from the light emitting element 128 enters the optical filter 130 is substantially the same regardless of the position. Therefore, there is no influence from the angle dependency of the optical filter 130, and the red light blocked by the optical filter 130 is not biased, preventing color unevenness in the main scanning direction of the scanned image.

[0077] The optical filter 130 formed in a roughly semi-cylindrical shape may be arranged so that one filter is provided for two light guides as in the first embodiment, or one filter is provided for each light guide as in the second and third embodiments.

[0078] (Fifth embodiment) Next, a fifth embodiment will be described with reference to FIG. In the first to third embodiments described above, the optical filter 130 is formed as a flat plate, but in the fifth embodiment, the optical filter 130 is formed in a spherical crown shape that protrudes toward the end face 110A of the light guide 110. The following description will focus on the differences from the first embodiment described above, and descriptions of overlapping parts will be simplified or omitted.

[0079] FIG. 17 is a schematic diagram illustrating the arrangement of the light guide 110 and the optical filter 130 in this embodiment. In this embodiment, as shown in Fig. 17, the optical filter 130 is formed in a spherical crown shape that protrudes toward the end surface 110A of the light guide 110. Here, as in the fourth embodiment described above, the spherical crown shape is formed in a curved shape such that the light emitting element 128 is located at the center of the sphere and the angle D formed between the light emitted from the light emitting element 128 to the optical filter 130 and the normal to the plane of the optical filter 130 is the same. The angle at which the light emitted from the light emitting element 128 enters the optical filter 130 is substantially the same regardless of the position. Therefore, there is no influence from the angle dependency of the optical filter 130, and the red light blocked by the optical filter 130 is not biased, preventing color unevenness in the main scanning direction of the scanned image.

[0080] The optical filter 130 formed in a spherical crown shape is disposed for each light guide, as in the second and third embodiments.

[0081] (Sixth embodiment) Next, a sixth embodiment will be described. In the first to fifth embodiments described above, the optical filter 130 is arranged at an angle, but in this sixth embodiment, the diffusion pattern 111 arranged at the center of the longitudinal direction of the light guide is formed by printing using ink that absorbs infrared light. The following description will focus on the differences from the first to fifth embodiments described above, and a description of overlapping parts will be simplified or omitted.

[0082] In this embodiment, the diffusion pattern 111 disposed on the longitudinal center side of the light guide 110 is formed by printing using ink that absorbs infrared light. Here, the longitudinal center side of the light guide 110 is a portion where red is output more strongly than other portions, for example, a portion located +50 mm and −50 mm from the longitudinal center of the light guide 110 (see FIG. 13 ). By absorbing infrared light from such portions of the light guide 110 where red is output more strongly than other portions, the difference in red output between the end sides where red is output less than the central side is reduced, thereby preventing color unevenness in the main scanning direction of the scanned image.

[0083] In this embodiment, the optical filter 130 of the first to fifth embodiments described above may be disposed, or the optical filter 130 may not be disposed.

[0084] Furthermore, in this embodiment, the diffusion pattern 111 arranged at the center of the longitudinal direction of the light guide 110 is not limited to being printed using ink that absorbs infrared light, but rather, before printing the diffusion pattern 111, infrared light absorbing ink may be applied to the center of the longitudinal direction of the light guide 110 in the printing area of ​​the diffusion pattern 111.

[0085] The present invention is not limited to the above-described embodiment, and various modifications and applications are possible within the scope of the gist of the present invention.

[0086] For example, in the above-described embodiment, two light guides 110 are provided, but one or three or more may be provided.

[0087] Furthermore, light emitting elements 128 are arranged on both ends of the light guide 110 to irradiate the light guide 110 with light, but this is not limited to this, and the light emitting elements 128 may be arranged on only one side. [Explanation of symbols]

[0088] 10 Image forming device 100 Image reader 110 Light guide 110A end face 110B Side 111 Diffusion Pattern 128 Light-emitting element 130 Optical Filter

Claims

1. A light source and a film-like optical filter that blocks light of a predetermined wavelength from the light source; a cylindrical light guide that guides light that has passed through the optical filter and entered one end surface to the other end surface, and that irradiates light that has exited from a side surface onto an illuminated object; a diffusion pattern for diffusing the light is disposed on the side of the light guide opposite to the illuminated object; the optical filter is disposed at a position facing the end surface of the light guide and obliquely disposed with respect to the end surface of the light guide, A reading device in which the optical filter is positioned so that the angle between the light from the light source and the normal to the plane of the optical filter is smaller on the side of the end face of the light guide facing the diffusion pattern than on the side facing the irradiated object.

2. The reading device according to claim 1 , wherein the optical filter is arranged at an angle so that the position of the end face of the light guide facing the diffusion pattern is farther from the light guide than the position facing the illuminated object.

3. Two of the light guides are provided in parallel, The light source is disposed for each of the light guides, 3. The reading device according to claim 1, wherein one optical filter is disposed on one of the end faces of the two light guides.

4. Two of the light guides are provided in parallel, The light source is disposed for each of the light guides, 4. The reading device according to claim 1, wherein the optical filter is disposed for each of the light guides.

5. The reading device according to claim 4 , wherein the optical filters are disposed on the one end surface and the other end surface of the light guide.

6. the diffusion pattern is disposed on one of the side surfaces of the two light guides, the side opposite to the object to be illuminated and away from the other light guide; The reading device described in claim 4 or claim 5, wherein the optical filter is arranged at an angle so that the end face of the light guide faces the diffusion pattern side rather than the side facing the illuminated body, and the position away from other optical filters is farther away from the light guide.

7. An image forming apparatus comprising the reading device according to any one of claims 1 to 6.

Images