JP6071953B2 - Illumination apparatus, image sensor unit, image reading apparatus, and image forming apparatus - Google Patents

Description

  The present invention relates to an illumination device, an image sensor unit, an image reading device, and an image forming device.

  Some illuminating devices used in image sensor units convert a point light source into a linear light source (linearized) using a rod-shaped light guide. Some light guides are provided with a diffusion pattern for diffusing light on the outer peripheral surface thereof in order to make the light irradiation intensity uniform in the longitudinal direction. As the diffusion pattern, for example, a prism pattern (see Patent Document 1) or a printing pattern protruding outward is applied. Further, the light guide may be provided with a light guide cover that covers the surface on which the above-described diffusion pattern is provided. For example, the light guide cover is provided with an opening for inserting the light guide, and the light guide cover is inserted into the light guide by sliding the light guide through the opening. Installing.

  However, in such a configuration, in the step of attaching the light guide cover to the light guide, the diffusion pattern provided on the light guide may come into contact with the light guide cover and the diffusion pattern may be worn out. If the gap between the diffusion pattern and the light guide cover is increased in order to prevent the wear of the diffusion pattern, the relative positional relationship between the light guide and the light guide cover increases. Becomes unstable. If it does so, there exists a possibility that the characteristic of the light irradiated through a light guide may become unstable.

JP 2014-033440 A

  In view of the above situation, the problem to be solved by the present invention is to suppress the wear of the diffusion pattern without destabilizing the characteristics.

The illuminating device of the present invention includes a light source, a light diffusion surface provided with a diffusion pattern for diffusing light emitted from the light source, and at least a part of the normal direction of the light diffusion surface relative to the diffusion pattern when viewed in the longitudinal direction. with a high protrusion to said light source and light guide rod-shaped is line light source of the light emitted is insertable the light guide body sliding from a predetermined direction, a part of the light guide A bar-shaped light guide cover that covers the light guide, and the light emitted from the light guide through the diffusion pattern on the inner peripheral side of the light guide cover, facing the light diffusion surface of the light guide The projections are provided on both sides of the diffusion pattern as viewed in the longitudinal direction, and the diffusion patterns are held by the projections so as not to contact the light reflection surface. characterized in that that.

  The image sensor unit of the present invention receives an illuminating device, a condensing body that collects reflected light emitted from the illuminating device and reflected by an illuminated body, and reflected light collected by the condensing body. And an image sensor for converting into an electrical signal, and a circuit board on which the image sensor is mounted, wherein the lighting device is the lighting device of the present invention.

  The image reading apparatus of the present invention is an image reading apparatus that reads reflected light from the illuminated body while relatively moving the image sensor unit and the illuminated body, and the image sensor unit is It is an image sensor unit.

  The image forming apparatus of the present invention includes an image reading unit that reads reflected light from the illuminated body while relatively moving the image sensor unit and the illuminated body, and an image forming unit that forms an image on a recording medium. The image sensor unit is an image sensor unit of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, it can suppress that a diffused pattern contacts a light guide cover and wears out, without enlarging the margin of the clearance gap between a diffused pattern and another member. Therefore, wear of the diffusion pattern can be suppressed without deteriorating the characteristics.

FIG. 1 is an exploded perspective view schematically illustrating a configuration example of a lighting device. FIG. 2 is an external perspective view schematically showing a configuration example of the lighting device. FIG. 3 is a perspective view schematically showing a configuration example of the light guide. FIG. 4 is an external perspective view of the vicinity of the end portions of the light guide and the light guide cover. FIG. 5 is a schematic cross-sectional view of the light guide and the light guide cover, and shows a state before the light guide cover is attached to the light guide. FIG. 6 is a schematic cross-sectional view of the light guide and the light guide cover, and shows a state where the light guide cover is attached to the light guide. FIG. 7 is a cross-sectional view schematically illustrating a configuration example of the diffusion pattern and the protruding portion of the light guide. FIG. 8 is an exploded perspective view schematically showing the configuration of the image sensor unit. FIG. 9 is an external perspective view schematically showing the configuration of the image sensor unit. FIG. 10 is a cross-sectional view schematically showing the internal structure of the image sensor unit. FIG. 11 is an external perspective view of the image reading apparatus according to the embodiment of the present invention. FIG. 12 is an external perspective view of the image forming apparatus according to the embodiment of the present invention. FIG. 13 is a perspective view showing an image forming unit provided in the housing of the image forming apparatus according to the embodiment of the present invention.

  Hereinafter, embodiments to which the present invention can be applied will be described in detail with reference to the drawings. In an embodiment of the present invention, an illumination device, an image sensor unit to which the illumination device is applied, and an image reading device and an image forming device to which the image sensor unit is applied are shown. In each figure, three-dimensional directions are indicated by X, Y, and Z arrows. The X direction is the main scanning direction of the image sensor unit. The Y direction is the sub-scanning direction of the image sensor unit. The Z direction is the vertical direction of the image sensor unit. Here, the side of the document P, which is an example of the illuminated body, is the upper side. The image sensor unit according to the embodiment of the present invention irradiates light on the document P by the illumination device while moving relative to the document P in the sub-scanning direction, and reads an image of the document P by the reflected light.

(Lighting device)
First, a configuration example of the illumination device 9 will be described. FIG. 1 is an exploded perspective view schematically showing a configuration example of the illumination device 9. FIG. 2 is a perspective view schematically showing an example of the assembly configuration of the lighting device 9. As shown in FIGS. 1 and 2, the lighting device 9 includes a light source 6, a light guide 3, and a light guide cover 8.

  The light source 6 includes, for example, light emitting elements having emission wavelengths of red (R), green (G), and blue (B). Various known LEDs can be applied to the light emitting elements having the emission wavelengths of the respective colors. The configuration of the light source 6 is appropriately set according to the specifications of the image sensor unit 1 and is not particularly limited. Further, the configuration (for example, the emission wavelength band) and the number of light emitting elements included in the light source 6 are not particularly limited. For example, the light source 6 may include an element that emits infrared rays or ultraviolet rays in addition to the light emitting elements of red, green, and blue as described above.

  The light guide 3 is an optical member that converts light emitted from the light source 6 into a linear light source (linearized). The light guide 3 has a rod-like configuration elongated in the main scanning direction, and is integrally formed from a transparent resin material such as an acrylic resin. At the end of the light guide 3 in the main scanning direction (longitudinal direction), a light incident surface 31 on which light emitted from the light source 6 is incident is provided. On the side surface of the light guide 3, there are provided a light diffusion surface 33 (see FIG. 3) for diffusing the incident light, and a light emission surface 32 that emits the light toward the outside (a document P which is an example of an illuminated body). It is done. Both of the light diffusion surface 33 and the light emission surface 32 have a strip shape elongated in the main scanning direction.

  The light guide cover 8 is a member that is attached to the light guide 3 and covers a part of the light guide 3. Similar to the light guide 3, the light guide cover 8 has a rod-like configuration that is long in the main scanning direction. The light guide cover 8 is integrally formed of a material having a high light reflectivity, such as white polycarbonate mixed with titanium oxide powder. The cross-sectional shape of the light guide cover 8 cut by a plane perpendicular to the longitudinal direction (main scanning direction) is substantially U-shaped, and one side in a predetermined direction perpendicular to the longitudinal direction is open. For this reason, the light guide 3 can be slidably inserted into the inner peripheral side of the light guide cover 8 from a predetermined direction (that is, the opening side) perpendicular to the main scanning direction.

  As shown in FIG. 2, the light guide cover 8 is attached to the light guide 3, and the light source 6 is provided at a position where the light incident surface 31 of the light guide 3 can be irradiated with light. If the illumination device 9 is configured to be applied to the image sensor unit 1, the light source 6 is mounted on the upper surface of a circuit board 5 (described later) of the image sensor unit 1, as shown in FIG. The light emitted from the light source 6 enters the light guide 3 from the light incident surface 31, diffuses at the light diffusing surface 33, and finally exits from the light emitting surface 32 toward the outside (original P). To do. Since the light emission surface 32 has a strip shape elongated in the main scanning direction, the light emitted from the light source 6 is converted into a linear light source (linearized) by the light guide 3 so as to be long in the main scanning direction. The

  Next, details of the configuration of the light guide 3 and the light guide cover 8 will be described with reference to FIGS. 3 and 4. FIG. 3A is a perspective view schematically showing the configuration of the light diffusion surface of the light guide 3, and is an enlarged view showing the vicinity of the end in the longitudinal direction (main scanning direction). FIG.3 (b) is the III-B part enlarged view of Fig.3 (a). FIG. 4 is a perspective view schematically showing the configuration of the light guide 3 and the light guide cover 8, and is an enlarged view showing the vicinity of one end in the longitudinal direction (main scanning direction). An arrow F in FIG. 4 indicates a direction in which the light guide 3 is inserted into the light guide cover 8. This direction is referred to as “insertion direction F”. The insertion direction F will be described later.

  The light incident surface 31 is provided at the end of the light guide 3 in the longitudinal direction. In the present embodiment, a configuration in which light incident surfaces 31 are provided at both ends in the longitudinal direction of the light guide 3 is shown (see FIG. 1). In this case, the illuminating device 9 has the two light sources 6, and each of the two light sources 6 is arrange | positioned in the position which can irradiate light toward each of the light-incidence surface 31 of both ends. However, the light incident surface 31 may be provided only at one end in the longitudinal direction. In this case, the illumination device 9 has one light source 6, and this one light source 6 is disposed at a position where light can be emitted toward the light incident surface 31 provided at one end of the light guide 3. The

  The light emitting surface 32 is provided on the side surface of the light guide 3. And the light-projection surface 32 has an elongate shape (for example, strip | belt shape) in a longitudinal direction. The length (longitudinal dimension) of the light emitting surface 32 is set according to the width (main scanning direction dimension) of the document P to which the image sensor unit 1 corresponds. For example, when corresponding to reading of an A3 size document P, the length of the light exit surface 32 is set to a dimension corresponding to the width of the A3 size document P. The light emitting surface 32 is formed in a curved surface that is convex toward the reading line O of the document P, for example, so that the reading line O (see FIG. 10) of the document P can be irradiated.

  The light diffusion surface 33 is also provided on the side surface of the light guide 3. The light diffusing surface 33 also has an elongated shape (for example, a belt shape) in the main scanning direction. As shown in FIGS. 3A and 3B, the light diffusion surface 33 is provided with a plurality of diffusion patterns 331. In the present embodiment, a prism structure that emits light incident from the light incident surface 31 toward the outside (in particular, a light reflecting surface 831 of the light guide cover 8 described later) is applied as the diffusion pattern 331. Specifically, the prism structure has a substantially triangular shape in cross section, and has a rib-like configuration protruding from the surface of the light diffusion surface 33 and extending in a direction perpendicular to the longitudinal direction. In addition, the inclination angle of the surface of the prism structure (the angle with respect to the surface of the light diffusion surface 33) is set to an angle at which the light incident from the light incident surface 31 and reaching the prism structure is not totally reflected. This angle is appropriately set according to the wavelength band of light emitted from the light source 6, the relative positional relationship between the light incident surface 31 and the prism structure, and the like. According to such a configuration, at least a part of the light that has entered the light incident surface 31 and reached the prism structure is emitted from the prism structure to the outside. The number and interval of the prism structures as the diffusion pattern 331 are not particularly limited. Further, the size and interval of the prism structure as the diffusion pattern 331 may not be uniform. Further, the diffusion pattern 331 may be a printed pattern made of paint that diffuses light. As the print pattern, for example, a dot pattern can be applied.

  The light diffusion surface 33 is inclined with respect to the insertion direction F of the light guide cover 8 when the light guide 3 is viewed in the longitudinal direction. The light diffusion surface 33 may not be parallel to the insertion direction F of the light guide cover 8 in the longitudinal direction of the light guide 3, and the inclination angle with respect to the insertion direction F of the light guide cover 8 is not particularly limited.

  The light guide cover 8 has a function of diffusing light incident on the light guide 3 and a function of improving light use efficiency. In the configuration in which the illumination device 9 is applied to the image sensor unit 1, the light guide cover 8 also has a function of positioning the light guide 3 on a frame 2 (described later) of the image sensor unit 1.

  The light guide cover 8 has a rod-like configuration. The cross-sectional shape of the light guide cover 8 cut by a plane perpendicular to the longitudinal direction (main scanning direction) is substantially U-shaped, and one side in a predetermined direction perpendicular to the longitudinal direction is open. For this reason, the light guide 3 can be inserted into the inner peripheral side of the light guide cover 8 from a predetermined direction perpendicular to the longitudinal direction. Specifically, it is as follows. Here, the description will be made based on the orientation of the state in which the light guide cover 8 is assembled to the image sensor unit 1. The light guide cover 8 includes a side wall portion 81, an upper wall portion 82, and a lower wall portion 83. The side wall 81 has a strip-like configuration that rises in the vertical direction and is long in the main scanning direction. The upper wall portion 82 has a flat plate-like or tongue-like configuration protruding from the upper end edge of the side wall portion 81 in one of the sub-scanning directions (the normal direction of the surface of the side wall portion 81). The lower wall portion 83 has a flat plate-like or tongue-like configuration protruding from the lower end edge of the side wall portion 81 in one of the sub-scanning directions (the same direction as the upper wall portion 82). For this reason, the light guide cover 8 has a substantially U-shaped cross section in which one side in the sub-scanning direction is opened. According to such a configuration, the direction perpendicular to the longitudinal direction and parallel to the protruding direction of the upper wall portion 82 and the lower wall portion 83 (in other words, the normal direction of the surface of the side wall portion 81) is inserted. The direction F is a predetermined direction perpendicular to the longitudinal direction. Then, the light guide 3 can be inserted into the inner peripheral side of the light guide cover 8 (a region surrounded by the side wall 81, the upper wall 82, and the lower wall 83) from a predetermined direction perpendicular to the longitudinal direction. It is. When the state in which the light guide cover 8 is assembled to the image sensor unit 1 is used as a reference, the light guide 3 can be inserted into the inner peripheral side of the light guide cover 8 from one side in the sub-scanning direction.

  However, the insertion direction F of the light guide 3 is not limited to a direction parallel to the sub-scanning direction. For example, the light guide 3 may be configured to be slidable in the main scanning direction from the end of the light guide cover 8 in the longitudinal direction (main scanning direction). Specifically, block-like or plate-like support portions that support the both end portions of the light guide 3 are provided at both ends in the longitudinal direction of the light guide cover 8, and these support portions penetrate in the longitudinal direction. A configuration in which a through hole is formed can be applied. With such a configuration, the light guide 3 can be slidably inserted into the light guide cover 8 by inserting the light guide 3 through a through hole formed in the support portion. In this case, the insertion direction F is a direction parallel to the main scanning direction.

  A light reflection surface 831 is provided on the inner peripheral side of the lower wall portion 83 of the light guide cover 8. The light reflecting surface 831 has a surface property that diffusely reflects light. The light reflecting surface 831 has an elongated shape (for example, a belt shape) in the longitudinal direction (main scanning direction) of the light guide cover 8. When the light guide 3 is inserted into the light guide cover 8, the light reflecting surface 831 and the light diffusion surface 33 provided on the light guide 3 face each other in parallel. However, it may be substantially parallel and may not be strictly parallel. In order to realize such a configuration, the light reflection surface 831 has the same angle as the light diffusion surface 33 of the light guide 3 with respect to the insertion direction F (a predetermined direction perpendicular to the longitudinal direction) of the light guide cover 8. (Or approximately the same angle).

  Thus, when the light guide 3 is inserted on the inner peripheral side of the light guide cover 8, the light diffusion surface 33 of the light guide 3 faces the light reflection surface 831 of the light guide cover 8. A part of the side surface of the light guide 3 is opposed to the inner peripheral surface of the side wall portion of the light guide cover 8. On the other hand, the light incident surface 31 and the light emitting surface 32 of the light guide 3 are exposed without being covered by the light guide cover 8. That is, when the light guide 3 is inserted on the inner peripheral side of the light guide cover 8, a part of the outer periphery of the light guide 3 is covered with the light guide cover 8.

  When the light guide 3 is inserted into the light guide cover 8, light incident from the light incident surface 31 of the light guide 3 can be diffused. Specifically, it is as follows. The diffusion pattern 331 provided on the light diffusion surface 33 has a shape in which light incident from the light incident surface 31 is not totally reflected. For this reason, at least a part of the light incident from the light incident surface 31 and reaching the diffusion pattern 331 is emitted from the surface of the diffusion pattern 331 to the outside. The light emitted to the outside from the diffusion pattern 331 is diffusely reflected on the light reflection surface 831 and enters the light guide 3 again from the light diffusion surface 33. Thus, since the light irregularly reflected on the light reflecting surface 831 is incident on the light guide 3 again, the light incident on the light guide 3 can be diffused. According to such a configuration, the illuminance distribution in the main scanning direction of the light emitted from the light emitting surface 32 can be made uniform.

  The light guide 3 and the light guide cover 8 are provided with positioning portions 35 and 84, respectively. As the positioning part 35 of the light guide 3, for example, a protrusion protruding in the insertion direction F from the side surface is applied. On the other hand, as the positioning portion 84 of the light guide cover 8, a through hole or a recess in which the positioning portion 35 of the light guide 3 can be engaged is applied. Then, the light guide 3 is positioned with respect to the light guide 3 by fitting the positioning portion 35 of the light guide 3 into the positioning portion 84 of the light guide cover 8.

  By the way, in this embodiment, the light guide 3 can be inserted into the inner peripheral side of the light guide cover 8 from a predetermined direction (one in the sub-scanning direction) perpendicular to the longitudinal direction of the light guide cover 8. When the light guide 3 is inserted into the inner peripheral side of the light guide cover 8, if the diffusion pattern 331 comes into contact with the inner peripheral surface of the light guide cover 8 (particularly, the inner peripheral surface of the lower wall portion 83), diffusion occurs. The pattern 331 may be worn out. Even in the configuration in which the light guide 3 is inserted into the light guide cover 8 by sliding it in the main scanning direction, the diffusion pattern 331 may be similarly worn out.

  Then, the structure which suppresses abrasion of the diffusion pattern 331 is demonstrated with reference to FIGS. 5 and 6 are diagrams schematically showing cross-sectional configurations of the light guide 3 and the light guide cover 8, and are views cut along a plane perpendicular to the longitudinal direction. 5 shows a state before the light guide 3 is inserted into the light guide cover 8, and FIG. 6 shows a state after the light guide 3 is inserted into the light guide cover 8. FIG. 7 is a cross-sectional view schematically showing the configuration of the light diffusion surface 33 of the light guide 3 and the vicinity thereof.

  The light diffusion surface 33 of the light guide 3 and the light reflection surface 831 of the light guide cover 8 are inclined with respect to the insertion direction F (sub-scanning direction in the present embodiment) in the longitudinal direction. Therefore, when the light guide 3 is inserted into the inner peripheral side of the light guide cover 8, the diffusion pattern 331 provided on the light diffusion surface 33 of the light guide 3 is formed on the inner peripheral surface of the light guide cover 8. Do not touch. Therefore, wear of the diffusion pattern 331 can be suppressed or prevented.

  Further, the light guide 3 is provided with a protruding portion 36 that protrudes outward (downward in FIGS. 5 to 7) in a direction perpendicular to the insertion direction F from the diffusion pattern 331. In particular, as shown in FIG. 6, the surface 361 of the protrusion 36 is parallel to the insertion direction F (that is, parallel to the longitudinal direction and the insertion direction F) when the light guide 3 is viewed in the longitudinal direction. And the surface 361 of the protrusion part 36 and its extended surface A (refer FIG. 7) pass through the vertex (the highest point from the surface of the light-diffusion surface 33) of the diffusion pattern 331, and are more than the surface B parallel to the insertion direction F. It is located outside (lower side in FIGS. 5 to 7).

  With such a configuration, when the light guide 3 is slidably inserted into the inner peripheral side of the light guide cover 8, the surface 361 of the projecting portion 36 is inside the lower wall portion 83 of the light guide cover 8. Contact the peripheral surface. For this reason, the diffusion pattern 331 is held by the protruding portion 36 so as not to contact the inner peripheral surface of the lower wall portion 83. Therefore, wear (for example, wear) due to contact of the diffusion pattern 331 can be suppressed. Further, even when the light guide 3 is accommodated in the light guide cover 8, the diffusion pattern 331 is held by the protrusion 36 so as not to contact the light reflecting surface 831. In addition, the protrusion part 36 is provided over the full length of a longitudinal direction. For this reason, the wear of the diffusion pattern 331 can be suppressed over the entire area of the light diffusion surface 33. According to such a configuration, wear of the diffusion pattern 331 can be suppressed without increasing the margin between the light diffusion surface 33 and the light reflection surface 831. Therefore, it is possible to suppress the characteristic from becoming unstable due to the enlargement of the margin.

  Further, the surface 361 of the protruding portion 36 contacts the inner peripheral surface of the light guide cover 8 when the light guide 3 is inserted into the light guide cover 8. Here, when the surface 361 of the protrusion 36 is parallel to the insertion direction F, the light guide 3 can be inserted smoothly.

  5 to 7 show the configuration in which the entire surface 361 of the protrusion 36 is located outside the diffusion pattern 331 in the direction perpendicular to the insertion direction F, the present invention is not limited to such a configuration. That is, it is only necessary that at least a part of the surface 361 of the protruding portion 36 is located outside the diffusion pattern 331 in the direction perpendicular to the insertion direction F. In short, the light guide 3 may have a configuration in which at least a part of the light guide 3 is provided with a protrusion 36 that protrudes outward in a direction perpendicular to the insertion direction F from the diffusion pattern 331.

  This configuration can also be explained as follows. As shown in FIG. 7, the diffusion pattern 331 protrudes outward from the light diffusion surface 33. A position C in FIG. 7 indicates the light diffusion surface 33 and its extended surface, and a position D indicates the highest position (position where the distance in the normal direction is the largest) from the light diffusion surface 33 of the diffusion pattern 331. . Further, the position E indicates the position of the protrusion 36 having the longest distance in the normal direction from the light diffusion surface 33. Note that the normal direction here refers to the normal direction of the light diffusion surface 33. As shown in FIG. 7, the position E is farther from the light diffusion surface 33 and its extended surface (position C) than the position D. In other words, the protruding portion 36 has a portion protruding in the normal direction from the light diffusion surface 33 and its extended surface. The maximum protruding height of this portion is larger than the maximum protruding height in the normal direction from the position C of the diffusion pattern 331. According to such a configuration, when the light guide 3 is inserted into the light guide cover 8 in a sliding manner from the insertion direction F, the diffusion pattern 331 of the light guide 3 is arranged on the inner peripheral side of the light guide cover 8. Do not touch the surface. Furthermore, even when the light guide 3 is inserted into the light guide cover 8 in a sliding manner in the longitudinal direction, the diffusion pattern 331 is formed on the inner peripheral surface of the light guide cover 8 (particularly, the light reflecting surface 831). Do not touch. With such a configuration, the diffusion pattern 331 can be prevented from contacting the inner peripheral surface of the light guide cover regardless of the direction in which the light guide 3 is inserted into the light guide cover 8. Therefore, wear of the diffusion pattern 331 can be suppressed.

  Moreover, as shown in FIG. 7, the protrusion part 37 is provided also in the opposite side to the side in which the protrusion part 36 is provided. The protruding portion 37 is a portion protruding in the normal direction from the light diffusing surface 33 and its extended surface rather than the position D. The position G indicates the position of the protrusion 37 that has the longest distance in the normal direction from the light diffusion surface 33 (position C). According to such a configuration, when the light guide 3 is inserted into the light guide cover 8, the diffusion pattern 331 of the light guide 3 does not contact the inner peripheral surface of the light guide cover 8.

  Thus, in this embodiment, the protrusion height from the diffusion surface 33 (the height in the normal direction of the diffusion surface 33) is the maximum protrusion of the diffusion pattern 331 on both sides of the light diffusion surface 33 in the longitudinal direction. Protrusions 36, 37 that are larger (or have larger portions) than the height (position D) are provided. When the protrusions 36 and 37 are provided on both sides of the diffusion surface 33 in the longitudinal direction, the protection of the diffusion pattern 331 is enhanced.

  Note that the protrusions 37 are not necessarily provided on both sides of the diffusion surface 33. That is, when the light guide 3 is inserted into the light guide cover 8, the surface of the outer peripheral surface of the light guide 3 that is parallel to the insertion direction F easily rubs against the inner peripheral surface of the light guide cover 8. . In the present embodiment, the lower surface in FIG. 7 is likely to rub against the inner peripheral surface of the light guide cover 8. Therefore, if the protrusion 36 is formed on one side of the diffusion surface 33 in the longitudinal direction as viewed from the lower side of the light guide 3, the diffusion pattern 331 has the inner periphery of the light guide cover 8. Contact with the surface is suppressed or prevented and protected. On the other hand, the surface on the opposite side is less likely to rub against the inner peripheral surface of the light guide cover 8 at the time of insertion compared to the lower surface. For this reason, the protrusion part 37 does not need to be provided in the opposite side. However, if the protrusions 36 and 37 are provided on both sides in the longitudinal direction, the protection of the diffusion pattern 331 is enhanced.

  On the other hand, when the insertion direction F is parallel to the main scanning direction, the diffusion surface 33 is parallel to the insertion direction F. For this reason, in this case, it is preferable that the protrusions 36 and 37 are provided on both sides of the diffusion surface 33 when viewed in the longitudinal direction. According to such a configuration, when the light guide 3 is inserted into the light guide cover 8, the diffusion pattern 331 is suppressed from rubbing against the inner peripheral surface of the light guide cover 8.

  Further, if the print pattern is applied as the diffusion pattern 331, the height of the protrusion 36 may be made larger than the thickness of the print pattern.

(Image sensor unit)
Next, a configuration example of the image sensor unit 1 will be described with reference to FIGS. FIG. 8 is an exploded perspective view schematically showing a configuration example of the image sensor unit 1. FIG. 9 is an external perspective view schematically showing a configuration example of the image sensor unit 1. FIG. 10 is a cross-sectional view schematically showing an example of the internal structure of the image sensor unit 1, and is a view cut along a plane perpendicular to the main scanning direction. As shown in FIGS. 8 to 10, the image sensor unit 1 has a rectangular parallelepiped configuration that is long in the main scanning direction. The image sensor unit 1 includes a lighting device 9, a frame 2, a light collector 4, and a circuit board 5. An image sensor 7 is provided on the circuit board 5.

  The frame 2 is a housing of the image sensor unit 1. The frame 2 accommodates and attaches the light guide 3 to which the light guide cover 8 is attached, the light collector 4, and the circuit board 5 on which the image sensor 7 and the light source 6 are mounted. The frame 2 is integrally formed of, for example, a resin material having a light shielding property colored in black. For example, polycarbonate can be used as the resin material.

  The frame 2 has a rectangular parallelepiped shape that is long in the main scanning direction. In the frame 2, a light guide housing chamber 27, a light collector housing chamber 28, and a circuit board housing chamber 29 (see FIG. 10) are formed. The light guide housing chamber 27 is an area opened on the upper side, and is configured to accommodate the light guide 3 to which the light guide cover 8 is attached. The light collector housing chamber 28 is an area opened on the upper side, and is configured to accommodate the light collector 4. The circuit board accommodation chamber 29 is an area opened on the lower side, and is configured to accommodate the circuit board 5 on which the light source 6 and the image sensor 7 are mounted. The frame 2 is formed with an opening S that allows light to pass through the light collector housing chamber 28 and the circuit board housing chamber 29. In addition, a presser claw 21 for positioning and fixing the light guide cover 8 accommodated in the light guide accommodation chamber 27 is formed on the frame 2. The holding claw 21 is an elastically deformable structure that protrudes toward the inside of the light guide housing chamber 27 and is integrally formed with the frame 2.

  The condenser 4 is an optical member that forms an image of the reflected light from the document P on the surface of the image sensor 7. For example, a rod lens array having a configuration in which a plurality of erecting equal-magnification imaging type imaging elements (rod lenses) are linearly arranged in the main scanning direction is applied to the condenser 4. The condensing body 4 is not limited as long as the imaging elements are linearly arranged. For example, the light collector 4 may have a configuration in which a plurality of imaging elements are arranged. Further, the light collector 4 may be an optical member having various conventionally known light collecting functions, such as various microlens arrays.

  The image sensor 7 converts the reflected light imaged by the light collector 4 into an electrical signal. For example, an image sensor IC array is applied to the image sensor 7. The image sensor IC array is configured by mounting a plurality of image sensor ICs linearly on the surface of the circuit board 5 in the main scanning direction. The image sensor IC includes a plurality of light receiving elements (sometimes referred to as photoelectric conversion elements) corresponding to the reading resolution of the image sensor unit 1. Thus, the image sensor 7 is configured by arranging a plurality of image sensor ICs (light receiving elements) in a straight line in the main scanning direction. The image sensor 7 only needs to have a configuration in which a plurality of image sensor ICs are arranged in a straight line, and other configurations are not particularly limited. For example, the image sensor ICs may be arranged in a plurality of rows like a staggered arrangement. In addition, conventionally well-known various image sensors and image sensor ICs are applicable to the image sensor IC which comprises the image sensor 7 and an image sensor IC array.

  The circuit board 5 has a rectangular configuration that is long in the main scanning direction. An image sensor 7 and a light source 6 are mounted on the upper surface of the circuit board 5. As shown in FIG. 8, the two light sources 6 are mounted in the vicinity of the end of the circuit board 5 in the main scanning direction so that light can be emitted toward the center in the main scanning direction. The image sensor 7 is mounted with the light receiving surface facing upward so that light from the light collector 4 can be received. Furthermore, connectors for connecting wiring with the outside are mounted on the circuit board 5.

  In addition, the image sensor unit 1 includes an attaching portion for attaching to the image reading apparatus 10 (described later) or the image forming apparatus 50 (described later), a connector for electrically connecting to the image reading apparatus 10 or the image forming apparatus 50, and the like. Is provided. In addition, the structure of an attaching part or a connector is not specifically limited. The attachment portion may be configured so that the image sensor unit 1 can be attached to the image reading apparatus 10 or the image forming apparatus 50. The connector may be configured to connect the image sensor unit 1 and a predetermined device of the image reading apparatus 10 or the image forming apparatus 50 so as to be able to transmit and receive power and electric signals.

  As shown in FIGS. 8 to 10, the light guide 3 to which the light guide cover 8 is attached is accommodated in the light guide accommodation chamber 27 of the frame 2. Then, the pressing claws 21 provided on the frame 2 engage with the light guide cover 8. Thereby, the light guide 3 and the light guide cover 8 are held in a state of being accommodated in the light guide accommodation chamber 27. Further, as shown in FIG. 10, the side surface of the light guide 3 is maintained in contact with the inner peripheral surface of the light guide housing chamber 27 by the biasing force of the biasing portion 85 of the light guide cover 8. . Thereby, the light guide 3 and the light guide cover 8 are positioned on the frame 2.

  Further, the light collector 4 is housed in the light collector housing chamber 28 of the frame 2. Further, the circuit board 5 on which the light source 6 and the image sensor 7 are mounted is accommodated in the circuit board accommodating chamber 29.

  When the light guide 3 is accommodated in the light guide accommodating chamber 27 and the circuit board 5 on which the two light sources 6 are mounted is accommodated in the circuit board accommodating chamber 29, each of the two light sources 6 is converted into the light guide 3b. It faces each of the light incident surfaces 31 formed at both ends. When the circuit board 5 on which one light source 6 is mounted is housed in the circuit board housing chamber 29, the one light source 6 faces the light incident surface 31 at one end of the light guide 3. Therefore, the light emitted from one or two light sources 6 enters a light incident surface 31 formed at one or both ends of the light guide 3.

  When irradiating the original P with light, the light source 6 sequentially turns on the light emitting elements of the respective colors. The light emitted from the light source 6 enters the light entrance surface 31 of the light guide 3 and propagates through the light diffusing surface 33 and other reflecting surfaces. Then, the light is emitted from the light emitting surface 32 of the light guide 3 toward the reading line O of the document P. As shown in FIG. 10, when the image sensor unit 1 is incorporated in the image reading apparatus 10 or the image forming apparatus 50, a document support 105 is disposed above the image sensor unit 1 (described later). . The illumination device 9 of the image sensor unit 1 irradiates light toward the reading line O of the document P placed on the document support 105. Reflected light from the reading line O of the original P is imaged on the surface of the image sensor 7 by the light collector 4. The image sensor 7 converts an optical image formed by the light collector 4 into an electrical signal. The image sensor unit 1 performs such an operation while moving relative to the document P in the sub-scanning direction. Thereby, the image sensor unit 1 can read the document P.

(Image reading device)
Next, an image reading apparatus 10 according to an embodiment of the present invention will be described with reference to FIG. The image sensor unit 1 according to the embodiment of the present invention is applied to the image reading apparatus 10 according to the embodiment of the present invention. FIG. 10 is an external perspective view of the image reading apparatus 10 according to the embodiment of the present invention. As shown in FIG. 10, the image reading apparatus 10 according to the embodiment of the present invention is a flat bed type scanner, and the image sensor unit 1 according to the embodiment of the present invention is incorporated therein. The image reading apparatus 10 includes a housing 102, a unit table 100, and a unit table driving mechanism.

  The unit table 100 is a member on which the image sensor unit 1 is mounted. The unit base drive mechanism is a mechanism for moving the unit base 100 on which the image sensor unit 1 is mounted in the sub-scanning direction. For example, the unit table drive mechanism includes a drive motor 103, a wire 104 that transmits power of the drive motor 103 to the unit table 100, and a guide shaft 107 that guides the unit table 100. The configurations of the unit base 100 and the unit base drive mechanism are not particularly limited, and conventionally known configurations can be applied. A document support 105 that supports a document P, which is an example of an illuminated body, is provided on the upper surface of the housing 102. For example, a transparent glass plate is applied to the document support 105. Further, a pressure plate 106 is attached to an end of the housing 102 in the sub-scanning direction so as to be opened and closed by a hinge or the like. The pressure plate 106 has a function of pressing the document P placed on the upper surface of the document support 105.

  The operation and use method of the image reading apparatus 10 is as follows. On the upper surface of the document support 105, the document P is placed downward, and the pressure plate 106 is closed. Then, the image sensor unit 1 is moved in the sub-scanning direction by driving the drive motor 103 and moving the wire 104. At this time, the unit table 100 is guided by the guide shaft 107. As a result, the image sensor unit 1 moves relative to the document P in the sub-scanning direction. Then, the image of the original P is read for each reading line while moving the image sensor unit 1. The image read by the image sensor unit 1 is subjected to image processing as necessary in the signal processing unit 109 and then stored as image data. Thereby, reading of the original P is completed.

  Note that, in the image reading apparatus 10 according to the embodiment of the present invention, the same configuration as that of a conventionally known image reading apparatus can be applied to portions where the description is omitted. Further, although the flat bed type scanner has been described as the image reading apparatus 10, the present invention can also be applied to a sheet feed type scanner.

(Image forming device)
Next, an image forming apparatus 50 according to an embodiment of the present invention will be described with reference to FIGS. The image sensor unit 1 according to the embodiment of the present invention is applied to the image forming apparatus 50 according to the embodiment of the present invention. FIG. 12 is an external perspective view of the image forming apparatus 50 according to the embodiment of the present invention. FIG. 13 is a perspective view illustrating the image forming unit 51 provided inside the housing of the image forming apparatus 50 according to the embodiment of the present invention. As shown in FIGS. 12 and 13, the image forming apparatus 50 is a multi-function printer (MFP) including a flatbed scanner and an inkjet printer. The image forming apparatus 50 includes an image reading unit 59 as an image reading unit that reads an image, and an image forming unit 51 as an image forming unit that forms an image. The image reading unit 59 of the image forming apparatus 50 incorporates the image sensor unit 1 according to the embodiment of the present invention. Note that the image reading unit 59 of the image forming apparatus 50 can be configured in common with the image reading apparatus 10 described above. Therefore, the same components as those of the image reading apparatus 10 are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 12, the image forming apparatus 50 is provided with an operation unit 501. The operation unit 501 is provided with a display unit 502 that displays an operation menu, various messages, and the like, and various operation buttons 503 for operating the image forming apparatus 50.

  As illustrated in FIG. 13, an image forming unit 51 is provided inside a housing 504 of the image forming apparatus 50. The image forming unit 51 includes a conveyance roller 52, a guide shaft 53, an ink jet cartridge 54, a motor 55, and a pair of timing pulleys 56. The conveyance roller 52 is rotated by the driving force of the driving source, and conveys the printing paper R as a recording medium in the sub scanning direction. The guide shaft 53 is a rod-shaped member, and is fixed to the housing of the image forming apparatus 50 so that its axis is parallel to the main scanning direction of the printing paper R. The ink jet cartridge 54 can reciprocate in the main scanning direction of the printing paper R by sliding on the guide shaft 53. The ink jet cartridge 54 includes, for example, an ink tank 541 (541C, 541M, 541Y, 541K) having cyan C, magenta M, yellow Y, and black K inks, and an ejection head 542 provided in each of these ink tanks 541. (542C, 542M, 542Y, 542K). One of the pair of timing pulleys 56 is attached to the rotation shaft of the motor 55. The pair of timing pulleys 56 are provided at positions separated from each other in the main scanning direction of the printing paper R. The timing belt 57 is wound around the pair of timing pulleys 56 in parallel, and a predetermined portion is connected to the ink jet cartridge 54.

  The image reading unit 59 of the image forming apparatus 50 converts the image read by the image sensor unit 1 into an electrical signal in a format suitable for printing. Then, the image forming unit 51 of the image forming apparatus 50 drives the conveyance roller 52, the motor 55, and the ink jet cartridge 54 based on the electrical signal converted by the image sensor unit 1 of the image reading unit 59, and prints an image on the printing paper R. Form. In addition, the image forming unit 51 of the image forming apparatus 50 can form an image based on an electric signal input from the outside. In the image forming apparatus 50, the configuration and operation of the image forming unit 51 can be the same as those of various conventionally known printers. Therefore, detailed description is omitted.

  As mentioned above, although embodiment of this invention was described in detail, above-mentioned embodiment is only a specific example in implementing this invention. The technical scope of the present invention is not limited to the above-described embodiment. The present invention can be variously modified without departing from the spirit of the present invention.

  For example, the image reading apparatus according to the present invention is not limited to the image scanner having the configuration described in the above embodiment. Further, the image forming apparatus is not limited to the ink jet system, and may be any system such as an electrophotographic system, a thermal transfer system, and a dot impact system, and is limited to the multifunction device described in the above embodiment. is not. Copiers and facsimile machines to which the image sensor unit according to the present invention is applied are also included in the present invention.

  In the embodiment, a configuration in which an illumination device having a light source and a light guide is used as a light source for reflection with respect to a document P, which is an example of a body to be illuminated, is shown, but the present invention is not limited to this configuration. For example, the structure which uses an illuminating device as a light source for transmission may be sufficient.

  INDUSTRIAL APPLICABILITY The present invention is effectively used for an illuminating device having a light guide, and an image sensor unit, an image reading device, and an image forming device to which the illuminating device is applied (for example, an image scanner, a facsimile machine, a copier, a multifunction machine, etc.). It can be done. And according to this invention, it suppresses or prevents that another member contacts the diffusion pattern of a light guide, without enlarging the margin of the clearance gap between a light guide and the other member attached to a light guide. it can. Therefore, wear of the diffusion pattern can be suppressed or prevented without degrading the characteristics.

1: Image sensor unit, 2: Frame, 3: Light guide, 31: Light incident surface, 32: Light emission surface, 33: Light diffusion surface, 331: Diffusion pattern, 4: Light collector, 5: Circuit board, 6: Light source, 7: Image sensor, 8: Light guide cover, 81: Side wall, 82: Upper wall, 83: Lower wall, 831: Light reflecting surface, 9: Illumination device, P: Document, O: Reading line

Claims (7)

A light source;
A light diffusion surface provided with a diffusion pattern for diffusing the light emitted from the light source, and a protrusion that is at least partially higher in the normal direction of the light diffusion surface than the diffusion pattern in the longitudinal direction, A rod-shaped light guide that converts light emitted from the light source into a linear light source;
The light guide can be slidably inserted from a predetermined direction, and a rod-shaped light guide cover that covers a part of the light guide,
A lighting device comprising:
On the inner peripheral side of the light guide cover, a light reflection surface is provided that faces the light diffusion surface of the light guide and reflects light emitted through the diffusion pattern,
The protrusions are provided on both sides of the diffusion pattern when viewed in the longitudinal direction,
The diffusing pattern is held by the protrusion so as not to contact the light reflecting surface . The light guide cover has a U-shaped cross section which opens the perpendicular predetermined direction in the longitudinal direction, said light guide to claim 1, characterized in that it is insertable from said predetermined direction The lighting device described. On the inner peripheral side of the light guide cover, a light reflecting surface that is inclined with respect to the predetermined direction is provided,
The light diffusion surface of the light guide is inclined with respect to the predetermined direction;
The lighting device according to claim 2 , wherein the light diffusion surface of the light guide is opposed to the light reflection surface of the light guide cover. The lighting device according to claim 2 , wherein the protrusion has a surface parallel to the predetermined direction. A lighting device;
A condenser for collecting the reflected light emitted from the illumination device and reflected by the illuminated body;
An image sensor that receives the reflected light collected by the light collector and converts it into an electrical signal;
A circuit board on which the image sensor is mounted;
Have
The lighting device, an image sensor unit, which is a lighting device according to any one of claims 1 4. An image reading device that reads reflected light from the object to be illuminated while relatively moving the image sensor unit and the object to be illuminated,
The image sensor unit according to claim 5 , wherein the image sensor unit is an image sensor unit. Image reading means for reading reflected light from the illuminated body while relatively moving the image sensor unit and the illuminated body;
Image forming means for forming an image on a recording medium;
An image forming apparatus comprising:
The image forming apparatus according to claim 5 , wherein the image sensor unit is an image sensor unit according to claim 5 .

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