JP6488717B2 - Image reading device - Google Patents

Description

  The present invention relates to an image reading apparatus used for a scanner or the like.

  Adoption of LED illumination has been advanced for a light source for irradiating a read original in a scanner or the like. There are two types of LED lighting: an array type in which a plurality of LED chips are arranged in the longitudinal direction and a light guide type. In the case of the light guide type, a high-intensity LED is arranged at the end, and the emitted light from the LED is totally reflected in the light guide extending in the longitudinal direction, and is configured to irradiate the document surface with a prism. The

  There are two types of scanner reading methods: mirror scan and unit scan. In contrast to the mirror scan that scans the document surface by scanning a total of three folding mirrors placed on the two sliders, the unit scan integrates the illumination, folding mirror, lens, and CCD into one module. It is read by scanning it.

  In mirror scanning, the weight of the slider to be scanned is light, and it is easy to scan the document surface at high speed. For this reason, mirror scanning is the mainstream in high-speed machines with high reading speed. On the other hand, the unit scan is excellent in image quality stability because it reads a document while maintaining a constant optical path. However, the unit scan has been adopted for a low-speed machine having a relatively low reading speed because the unit weight to be scanned becomes heavy.

  However, in recent years, CCD substrates and lenses have been reduced in size due to reduction in CCD pixel size and higher illumination of LED lighting. Therefore, it is possible to reduce the size and weight of the reading unit in the unit scan, and it is considered that the adoption of the unit scan is advanced even in the high-speed machine region. In unit scanning, it is necessary to adjust and position optical components with high accuracy, and therefore, a method for constructing a unit with little distortion and deformation is an important issue.

  In the light guide type LED illumination, in order to irradiate the original surface with the correct light distribution, it is important that the light guide is accurately arranged. However, the light guide is made of a resin such as transparent acrylic. Made. Therefore, a holding member that restricts the warpage and performs positioning is required.

  Therefore, for example, as disclosed in Patent Document 1, the LED, the light guide, and the holding member are generally positioned and fixed with respect to a base made of sheet metal, and configured as an LED module. By fixing each component with high accuracy in this way, light incident on the light guide from the LED can be diffused by the prism and emitted to the document surface with accurate light distribution.

  Here, the configuration of a conventional LED module (one form of illumination module) disclosed in Patent Document 1 will be specifically described with reference to FIG. The configuration of this configuration is a light guide type, and an LED 102 is disposed at an end portion in the longitudinal direction, and light emitted therefrom is made incident on the light guide 101. The light travels while being totally reflected in the light guide, but a prism is engraved on the light guide, and the light hitting the prism is diffused and applied to the document surface.

  Since the illumination used in the image reading apparatus requires a uniform and stable light distribution, the light guide type creates a light distribution by tuning and optimizing the shape of the prism and the light guide. However, since the light guide used in the light guide type is made of transparent acrylic having a high transmittance, there is a problem that warpage is likely to occur during molding or temperature change.

  In order to correct this warpage, the light guide is corrected and held by the holding member 105. These parts are positioned and held with respect to a metal base 120 having sufficient rigidity. For the CCD module, the light distribution center of illumination is aligned with the object plane position of the reduction optical system created by the CCD module by directly positioning and holding the base.

  On the other hand, the CCD module that is assembled under the LED module and holds the optical components necessary for reading is in a state in which the line-of-sight position adjustment and MTF adjustment are performed with the LED module attached, and the target reading performance is achieved. Is assembled to the scanner housing and shipped after image inspection.

JP 2010-107757 A Japanese Patent No. 5470310

  In the market after shipment, parts may be replaced when LED lighting reaches the end of its life or when a problem occurs. At that time, if only the LED module is replaced while leaving the unit as it is, there is a slight shape error between the old LED module and the new one.

  For this reason, the CCD module is pulled by the rigidity of the LED module, and distortion occurs before and after replacement. As a result, the positional accuracy of the optical component attached to the optical component is out of order, which causes a decrease in reading performance. In order to avoid this, since it is necessary to replace the reading unit with the LED module, the cost for the replacement becomes very large.

  For example, even in the conventional device described above, when the LED module is assembled on the CCD module, the CCD module is pulled by the rigidity of the LED module due to the backlash of the component accuracy of each other, and a minute distortion occurs. At the time of assembly, the optical performance of each reading unit can be adjusted to the target value in a state where the CCD module and the LED module are combined, and the minute distortion is not particularly problematic.

  However, in the market, the LED module may be replaced as a single unit due to the end of life or trouble of the LED. At that time, if a new LED module is attached to the CCD module, the CCD module will be distorted differently from the original. In order to correct the deterioration of the optical performance due to the distortion, it is necessary to readjust the reading unit, which makes it difficult to respond in the market.

  In order to solve this, there is a method of replacing the reading unit as described above. However, it is costly to replace an expensive lens and a CCD module including a CCD each time an abnormality occurs in the LED. Very wasteful. In addition, by making the rigidity of the reading unit extremely large compared to the LED module, it is possible to reduce the distortion caused by the replacement of the LED module, but for that purpose, it is necessary to increase the thickness of the sheet metal constituting the unit, This leads to an increase in unit weight and cost.

  In view of the above-described problems, an object of the present invention is to provide an image reading apparatus in which an illumination module can be replaced while maintaining optical performance without increasing unit weight and cost.

  An image reading apparatus according to the present invention includes an illumination module that irradiates light from a light source onto a document via a light guide member, and reflected light from the document by a plurality of reflecting members, and forms an image on an image sensor by a lens. An image reading apparatus including an imaging module constituting a reduction optical system, wherein the imaging module has a box shape extending in a predetermined longitudinal direction by fastening and fixing a lower housing and an upper housing at a plurality of positions. A shape is formed, and the reflecting member and the lens are held in the box shape, and a resin holding member that holds the light guide member is arranged in the longitudinal direction with respect to the upper housing. It is configured to be supported so that movement is regulated in a predetermined direction at a plurality of locations.

  According to this configuration, the illumination module can be replaced while maintaining the optical performance without increasing the unit weight or cost.

  More specifically, in the above configuration, the light guide member is formed so as to reflect the light from the LED and irradiate the document surface with a prism, and a CCD is used as the imaging element. It is good also as composition which has.

  More specifically, the holding member has a plurality of protrusions in the longitudinal direction, and the protrusions are inserted into holes in the upper housing so as to be orthogonal to the longitudinal direction. The restriction may be made in the height direction and the short direction. More specifically, as the above configuration, at least a part of the protrusion may be formed as a claw-shaped hooking claw.

  More specifically as the above configuration, an extension projecting from the box shape is provided at the end in the longitudinal direction of the upper housing and the lower housing, and the lighting module includes the extension It is good also as a structure which has the heat radiating member fastened and held by the said upper housing or the said lower housing.

  More specifically, the light guide member has a first light guide and a second light guide, and the light from the light source is branched by these light guides in the longitudinal direction. It is good also as a structure which is formed so that it may guide and irradiates light to the original from both the 1st light guide and the 2nd light guide.

  According to the image reading apparatus of the present invention, the illumination module can be replaced while maintaining the optical performance without increasing the unit weight or cost.

1 is a configuration diagram of an image reading apparatus according to an embodiment. It is sectional drawing of the reading unit in this embodiment. It is a perspective view of the LED module which concerns on this embodiment. It is a perspective view of the CCD module which concerns on this embodiment. It is an enlarged view of the edge part vicinity of the longitudinal direction in FIG. It is a perspective view of the back surface side of the LED module which concerns on this embodiment. It is an enlarged view of the edge part vicinity of the longitudinal direction in FIG. It is a top view of the LED module which concerns on this embodiment. It is explanatory drawing regarding the conventional LED module.

  Embodiments of the present invention will be described below with reference to the drawings. However, the content of the present invention is not limited to the embodiment.

  FIG. 1 is a configuration diagram (schematic cross-sectional view seen from the side) of an image reading apparatus 1 according to the present embodiment. As shown in the figure, the image reading apparatus 1 includes a platen glass 3 on which a document 2 is placed, and a reading unit 4.

  The reading unit 4 is movably attached inside the image reading apparatus 1. The reading unit 4 is configured to scan the lower part of the document 2 placed on the platen glass 3 and read the document 2.

  FIG. 2 is a cross-sectional view of the reading unit 4 in the present embodiment. The reading unit 4 includes an LED module M1 (one form of a light source module) that irradiates the document 2 and a CCD module M2 (one form of an imaging module) that forms an image of reflected light from the document 2 on an image sensor.

  The CCD module M2 includes a CCD substrate 11 provided with a mirror (reflecting member) 9, a lens (imaging member) 10, and a CCD (imaging device). In the present embodiment, a plurality of mirrors (9a to 9e) are provided as the mirror 9. The reflected light from the surface of the document 2 illuminated by the LED module M1 is folded by a plurality of mirrors (9a to 9e) and imaged by the lens 10 onto the light receiving surface of the CCD.

  FIG. 3 is a perspective view of the LED module M1. The LED module M1 is a light guide type, and has a shape extending in a predetermined longitudinal direction (corresponding to the depth direction in FIG. 2; the same applies hereinafter). The LED module M <b> 1 has an LED (light source) 12 disposed at an end in the longitudinal direction, and a light guide (light guide member) 5 is supported by a holding member 6.

  With the above configuration, the LED module M <b> 1 irradiates the document 2 with light from the LED 12 through the light guide 5. The light guide 5 is formed so as to reflect the light from the LED 12 inside and to irradiate the document 2 with a prism. The holding member 6 is made of resin and has low rigidity, and the holding member 6 is not designed to correct warpage of the light guide 5 alone.

  FIG. 4 is a perspective view of the CCD module M2. FIG. 5 is an enlarged view of the vicinity of the end in the longitudinal direction in FIG. The LED module M1 is attached to the CCD module M2 shown in FIG. At that time, the LED module M1 is attached to the CCD module M2 so that the holding member 6 is positioned with respect to the upper housing 7 of the CCD module M2, and the warp direction is corrected at a plurality of positions in the longitudinal direction. become.

  The CCD module M2 has high rigidity by forming a box shape in which the upper housing 7 is fastened at a plurality of locations on the lower housing 8 made of sheet metal, and extends in the longitudinal direction. Note that the above-described mirror 9 and lens 10 are held in the box shape.

  The CCD module M2 has a high rigidity by forming a box shape as described above. Therefore, even if there is a minute difference between the shapes of the holding member 6 and the upper housing 7, the upper housing 7 and the CCD module M2 side are not easily affected by distortion. On the other hand, since the holding member 6 is regulated by the upper housing 7 having high rigidity, it is possible to correct the warp of the light guide 5 and to directly position the CCD module M2, so that the holding member 6 is highly accurate. The image plane of the reduction optical system can be irradiated.

  In the present embodiment, the resin-made holding member 6 that holds the light guide 5 is supported with respect to the upper housing 7 so as to be restricted in a predetermined direction at a plurality of positions in the longitudinal direction. Hereinafter, this point will be described more specifically.

  FIG. 6 is a perspective view of the back side of the LED module M1. FIG. 7 is an enlarged view of the vicinity of the end in the longitudinal direction in FIG. As shown in these drawings, a plurality of hooking claws 16 and restriction projections 17 are provided on the back surface of the holding member 6. The hooking claw 16 is formed in a claw shape so that it can be hooked into the hole. As shown in FIG. 6, the hooking claws 16 are provided with a plurality of hooking claws (16 a to 16 f), and the restriction protrusions 17 are provided with a plurality of restriction protrusions (17 a to 17 g).

  A protrusion 18 projecting in the longitudinal direction is provided at an end of the LED module M1 in the longitudinal direction. The CCD module M <b> 2 is provided with an engagement hole 19 corresponding to the protrusion 18, and the protrusion 18 can be fitted into the engagement hole 19.

  The restriction protrusion 17 has a cylindrical shape, and is positioned with respect to the restriction hole 15 provided in the upper housing 7 to restrict movement in the short direction. Here, the short direction corresponds to the left-right direction in FIG. 2 (perpendicular to the longitudinal direction). As shown in FIG. 4, the restriction holes 15 are provided with a plurality of restriction holes (15 a to 15 g) so as to correspond to the restriction protrusions (17 a to 17 g).

  The hooking claw 16 is attached so as to be hooked in the hooking hole 14 provided in the upper housing 7, and can restrict the movement of the holding member 6 in the height direction. Here, the height direction corresponds to the vertical direction in FIG. 2 (perpendicular to both the longitudinal direction and the short direction). As shown in FIG. 4, the hooking holes 14 are provided with a plurality of hooking holes (14 a to 14 f) so as to correspond to the hooking claws (16 a to 16 f).

  Due to the two restrictions by the restriction protrusion 17 and the hooking claw 16 described above, it is possible to suppress the warpage that occurs in the height / short direction of the holding member 6 and the light guide 5. At this time, the restriction hole 15 and the hooking hole 14 are not restricted in that direction because there is a gap in the longitudinal direction of the holding member 6.

  Thereby, even if a temperature change occurs and the resinous light guide 5 and the holding member 6 are thermally expanded, a difference in length from the metal upper housing 7 can be caused to escape in the longitudinal direction. . Therefore, it is possible to prevent the generation and deformation of stress.

  As described above, the holding member 6 has a plurality of protrusions (the hooking claws 16 and the restricting protrusions 17) in the longitudinal direction. The protrusions are inserted into the holes (the hooking holes 14 and the restriction holes 15) in the upper housing 7, thereby restricting the movement in the height direction and the short direction perpendicular to the longitudinal direction.

  As shown in FIGS. 4 to 5, the upper housing 7 and the lower housing 8 constituting the CCD module M <b> 2 are arranged at the longitudinal ends (the ends opposite to the side where the engagement holes 19 are provided). The non-box-shaped extension 20 protrudes from the box shape. By fastening and fixing the heat radiating member 13 at the end of the LED module M1 to the extension portion 20 with screws, the heat emitted from the heat radiating member 13 can be released to the upper and lower housings (7, 8), and the heat radiating performance is improved. Is possible.

  The optical components in the CCD module M2 are arranged in the box-shaped portion of the upper and lower housings (7, 8). For this reason, the distortion generated by screwing the extension portion 20 does not affect the optical performance of the optical component.

  As described above, the extended portions 20 protruding from the box shape are provided at the longitudinal ends of the upper housing 7 and the lower housing 8. The LED module M <b> 1 has a heat radiating member 13 that is fastened and held to the upper housing 7 or the lower housing 8 in the extension portion 20.

  FIG. 8 shows a top view of the LED module M1. As shown in the figure, in the LED module M1, as the light guide 5, two light guides (first light guide 5a and second light guide 5b) which are divided into left and right and extend in the longitudinal direction are provided. ing. Each of these light guides (5a, 5b) is configured to totally reflect the light from the LED 12, guide it in the longitudinal direction, and irradiate the document 2 with the prism. Thereby, the light from the LED 12 is branched and guided in the longitudinal direction by the respective light guides (5a, 5b), and is irradiated onto the document 2.

  The LED module M1 is configured to irradiate the document 2 with light from both the first light guide 5a and the second light guide 5b. As a result, in the present embodiment, since the document 2 is irradiated from both sides of the first light guide 5a and the second light guide 5b, the normally provided reflecting mirror is unnecessary, and the positioning and holding of the reflecting mirror is not necessary. Absent.

  Therefore, the components constituting the LED module can be only four components of the LED 12, the heat radiating member 13, the light guide 5, and the holding member 6, which is suitable for the implementation of the present invention. The light emitted from each light guide (5a, 5b) becomes reflected light from the document 2, and reaches the mirror 9 through between the first light guide 5a and the second light guide 5b.

  As described above, the image reading apparatus 1 uses the LED module M1 that irradiates light from the LED 12 to the document 2 via the light guide 5 and the reflected light from the document 2 by the plurality of mirrors 9 to return the lens 10. And a CCD module M2 constituting a reduction optical system that forms an image on the CCD.

  The CCD module M2 has a box shape extending in the longitudinal direction by fastening the lower housing 8 and the upper housing 7 at a plurality of positions, and the mirror 9 and the lens 10 are held in the box shape. It has a configuration. In addition, a resin holding member that holds the light guide 5 is supported by the upper housing 7 so as to be restricted in a predetermined direction at a plurality of locations in the longitudinal direction. Therefore, according to the image reading apparatus 1, the LED module M1 can be replaced while maintaining the optical performance without increasing the unit weight or cost.

  As mentioned above, although the specific example was given and demonstrated about embodiment of this invention, this invention is not limited to the content. The present invention can be implemented in various specific forms without departing from the spirit of the present invention.

  The present invention can be used for a scanner or the like.

DESCRIPTION OF SYMBOLS 1 Image reader 2 Original 3 Platen glass 4 Reading unit 5 Light guide 5a 1st light guide 5b 2nd light guide 6 Holding member 7 Upper housing 8 Lower housing 9, 9a-9e Mirror 10 Lens 11 CCD board 12 LED
13 Heat radiation member 14, 14a-14f Hooking hole 15, 15a-15g Restriction hole 16, 16a-16f Hook claw 17, 17a-17g Restriction projection 18 Projection 19 Engagement hole 20 Extension part M1 LED module M2 CCD module

Claims (5)

An illumination module that irradiates the original with light from the light source via the light guide member;
An image reading apparatus comprising: an imaging module that constitutes a reduction optical system that folds reflected light from the document by a plurality of reflecting members and forms an image on an image sensor with a lens;
The imaging module is
A box shape extending in a predetermined longitudinal direction is formed by fastening and fixing the lower housing and the upper housing at a plurality of positions, and the reflection member and the lens are held in the box shape. ,
A resin-made holding member that holds the light guide member is supported with respect to the upper housing so that movement is restricted in a predetermined direction at a plurality of locations in the longitudinal direction ,
At the end in the longitudinal direction of the upper housing and the lower housing, an extension projecting from the box shape is provided,
The illumination module includes an image reading apparatus which is characterized that you have a heat dissipation member that is fastened retained on said housing or the lower housing in the extended portion. The light guide member is formed so as to reflect light from the LED, which is the light source, and irradiate the document surface with a prism.
The image reading apparatus according to claim 1, wherein a CCD is used as the imaging element. The holding member has a plurality of protrusions in the longitudinal direction,
The image reading apparatus according to claim 1, wherein the restriction is performed in a height direction and a short direction perpendicular to the longitudinal direction by inserting the protrusion into a hole in the upper housing.   The image reading apparatus according to claim 3, wherein at least a part of the protrusion is formed as a claw-shaped hooking claw. The light guide member is
Having a first light guide and a second light guide, each of these light guides is formed to guide the light from the light source in the longitudinal direction;
The image reading apparatus according to any one of claims 1 to 4 for irradiating light to the document from both the first light guide body and the second light guide body.