JP2020120238A - Image reading device and image forming apparatus including the same - Google Patents

Abstract

To provide an image reading device that can read irregularities of an object to be read, while preventing an increase in size in the vertical direction, and an image forming apparatus including the same.SOLUTION: An image reading device 10 comprises: a contact glass 11; an illumination unit 20 that illuminates a document Q with light; a CCD sensor 16 that receives reflected light from the document Q; plate-like prism sheets 70 that change the direction of travel of light emitted from the illumination unit 20 to change the angle of incidence of the light with respect to the document Q; and a sheet moving mechanism 90 that moves the prism sheets 70. The illumination unit 20 has a first light guide member 21 and a second light guide member 22, and light sources 27. The prism sheets 70 are selectively arranged by the sheet moving mechanism 90 at angle changing positions to change the direction of travel of the light emitted from the illumination unit 20 to change the angle of incidence of the light with respect to the document Q, and retracted positions not to change the direction of travel of the light emitted from the illumination unit 20 not to change the angle of incidence of the light with respect to the document Q.SELECTED DRAWING: Figure 8

Description

The present invention relates to an image reading device used for a digital copying machine, an image scanner, or the like for reading an image of an object to be read and an image forming apparatus including the image reading device.

Conventionally, a contact glass on which a document (read object) is placed, an illuminating device including a light source disposed under the contact glass, a CCD sensor which receives reflected light from the document and converts it into an electric signal, and the like. An image reading device including a photoelectric conversion unit is known.

The image reading device usually reads an image recorded on a flat surface such as a printed matter or a photograph, but is also required to read unevenness (emboss information) formed on a credit card, a Braille document or the like.

Therefore, in a normal reading mode for reading an image of an original having no unevenness on the surface, a first illuminating device that irradiates the original with light from the front side, and a credit card or Braille document having an unevenness on the surface (read target) An image reading apparatus is known that includes a second illuminating device that irradiates an object to be read with light from an oblique direction in an emboss reading mode for reading unevenness of a body (see, for example, Patent Document 1). The first illumination device includes eight first light sources and a concavely curved reflecting plate that reflects the light from the first light source toward the original. The second illumination device includes ten second light sources and two lenses that guide light from the second light source to the object to be read. The diffusion plate is arranged so as to cover the first light source, the second light source, and the lens.

In this image reading apparatus, when the first illuminating device is used, a shadow is generated by irradiating the document with light from the front direction even if the document has wrinkles or folds. Since the above can be suppressed, the image of the document can be read. Further, when the second illumination device is used, by irradiating the object to be read with light from an oblique direction, a shadow is generated according to the unevenness of the object to be read, so that the unevenness can be read.

JP, 2007-48046, A

However, in the above-mentioned conventional image reading apparatus, the reflecting plate curved in a concave shape is arranged so as to cover the first light source, the second light source, and the upper part of the lens, so that the image reading apparatus becomes large in the vertical direction. There was a problem that it would end up.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an image capable of reading unevenness of a read object while suppressing an increase in size in the vertical direction. A reading device and an image forming apparatus including the reading device are provided.

In order to achieve the above-mentioned object, an image reading apparatus according to a first aspect of the present invention is provided with a contact glass on which an object to be read is placed and below the contact glass, and irradiates the object to be read with light. The illumination unit, the photoelectric conversion unit that receives the reflected light from the object to be read, converts the received reflected light into an electric signal and outputs the electric signal, and is disposed between the illumination unit and the contact glass and emitted from the illumination unit. A flat prism sheet that changes the traveling direction of light to change the incident angle of light on the object to be read, and a sheet moving mechanism that moves the prism sheet. The illumination unit extends in the main scanning direction and is arranged on one side and the other side of the sub-scanning direction with respect to the optical axis of the light reflected by the object to be read and received by the photoelectric conversion unit. A first light guide member and a second light guide member which are emitted toward the object to be read while being guided along, and one end of the first light guide member in the main scanning direction and the other end of the second light guide member in the main scanning direction. And a light source arranged to face a light incident surface formed at each end. The prism sheet uses a sheet moving mechanism to change the traveling direction of the light emitted from the illumination unit and the angle changing position for changing the incident angle of the light on the object to be read, and the traveling direction of the light emitted from the illumination unit. Instead, it is selectively arranged at a retracted position where the incident angle of light with respect to the object to be read is not changed.

According to the image reading device of the first aspect of the present invention, the prism sheet has an angle at which the sheet moving mechanism changes the traveling direction of the light emitted from the illumination unit to change the incident angle of the light on the object to be read. The change position and the retracted position that does not change the traveling direction of the light emitted from the illumination unit and does not change the incident angle of the light with respect to the reading target are selectively arranged. Accordingly, even when the object to be read has wrinkles or folds, it is possible to prevent the shadow from being generated by irradiating the object to be read with light from the front direction. The image on the reader can be read. Further, by irradiating the object to be read with light from an oblique direction, a shadow is generated in accordance with the unevenness of the object to be read, so that the unevenness can be read.

Further, since the flat prism sheet is arranged between the illuminating section and the contact glass, the image reading device is arranged in the vertical direction as compared with the conventional image reading device in which the reflecting plate curved in a concave shape is arranged above the light source. It is possible to suppress the increase in size.

Since the first light guide member and the second light guide member that extend in the main scanning direction and emit light toward the object to be read while guiding the light along the main scanning direction are used to illuminate the object to be read. Unlike the case where the object to be read is directly illuminated by a plurality of light sources arranged along the main scanning direction (for example, in the case of the conventional image reading apparatus described above), the object to be read can be uniformly illuminated in the main scanning direction. it can.

FIG. 1 is a front sectional view showing an internal configuration of an image forming apparatus including an image reading device according to an embodiment of the present invention. It is a front sectional view showing an internal configuration of an image reading apparatus according to an embodiment of the present invention. 1 is a top view of an image reading device according to an embodiment of the present invention. It is a figure which shows the structure of a 1st light guide member and a 2nd light guide member periphery of the image reading apparatus of one Embodiment of this invention, and is a figure which shows the advancing direction of light when a prism sheet is arrange|positioned in a retracted position. .. It is a figure which shows the structure of a 1st light guide member and a 2nd light guide member periphery of the image reading apparatus of one Embodiment of this invention, and is an image figure which shows the advancing direction of light when a prism sheet is arrange|positioned in a retracted position. .. It is a figure which shows the internal structure of the optical unit of the image reading apparatus of one Embodiment of this invention. FIG. 3 is a top view showing the internal structure of the optical unit of the image reading apparatus according to the embodiment of the present invention. It is a figure which shows the structure around the 1st light guide member and the 2nd light guide member of the image reading apparatus of one Embodiment of this invention, and is a figure which shows the advancing direction of light when a prism sheet is arrange|positioned at an angle change position. is there. It is a figure which shows the structure of the 1st light guide member and 2nd light guide member periphery of the image reading apparatus of one Embodiment of this invention, and is an image figure which shows the advancing direction of light when a prism sheet is arrange|positioned in an angle change position. is there. FIG. 3 is an enlarged view showing the structure of the prism of the prism sheet of the image reading device according to the embodiment of the present invention. FIG. 3 is an enlarged view showing the structure of the prism of the prism sheet of the image reading device according to the embodiment of the present invention. FIG. 6 is a diagram of the light emitted from the first light guide member and the second light guide member when the prism sheet of the image reading apparatus according to the embodiment of the present invention is arranged at the retracted position, as viewed from the sub-scanning direction. FIG. 7 is a diagram of light emitted from the first light guide member and the second light guide member when the prism sheet of the image reading apparatus according to the embodiment of the present invention is arranged at the angle changing position, as viewed from the sub-scanning direction. FIG. 3 is a block diagram showing an example of a control path of the image reading apparatus according to the embodiment of the present invention.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a front sectional view showing an internal configuration of an image forming apparatus 100 including an image reading apparatus 10 according to an embodiment of the present invention, and FIG. 2 is an image reading apparatus 10 according to an embodiment of the present invention. FIG. 3 is a front cross-sectional view showing the internal structure, and FIG. 3 is a top view of the image reading device 10 according to the embodiment of the present invention.

As shown in FIG. 1, the image forming apparatus 100 includes a sheet feeding unit 1 disposed at a lower portion of the apparatus main body, a sheet conveying unit 2 disposed on the right side and an upper side of the sheet feeding unit 1, and a sheet conveying unit. The image forming section 3 arranged above the section 2, the fixing section 4 arranged downstream of the image forming section 3 in the sheet conveying direction, and the fixing section 4 arranged above the image forming section 3 and the fixing section 4. The image reading device 10 is provided, and the document feeding device 6 is provided above the image reading device 10.

The sheet conveying section 2 conveys the sheet (recording medium) fed from the sheet feeding section 1 toward the image forming section 3, and further conveys the sheet on which the image is formed in the fixing section 4 from the image forming section 3. The sheet is discharged onto the discharge tray 7.

The image forming unit 3 forms a predetermined toner image on the sheet based on the image data of the document read by the image reading apparatus 10 by the electrophotographic process. The fixing unit 4 fixes the toner image on the sheet on which the toner image is transferred by the image forming unit 3.

The document feeder 6 automatically feeds the documents placed on the document tray 8 one by one in response to the input of a command to start copying (copying), and the document discharge tray ( The original is read by a so-called sheet-through method, in which the original is discharged (not shown).

The image reading device 10 reads the image information of the document by irradiating the document conveyed by the document conveying device 6 or the document placed on the contact glass with light and converting the reflected light into an electric signal. The image data corresponding to the original image is generated.

As shown in FIG. 2, the image reading apparatus 10 includes an illumination unit 20 that irradiates the image surface of the document Q (the lower surface in FIG. 2) with light, and a reflected light (image light) from the document Q that receives electricity. A CCD sensor (photoelectric conversion unit) 16 for converting into a signal is provided, and it is possible to read the image of the document Q and the unevenness described later. Note that, in FIG. 2, the optical path of the reflected light of the document is shown by a one-dot chain line.

As shown in FIGS. 2 and 3, the contact glass 11 is provided on the upper surface of the image reading device 10, and the left end of the document Q (one end of the sub scanning direction (arrow Y direction) when reading the document Q by the document fixing method). A positioning member 12 for abutting and positioning the left end of FIG. 2 and a positioning member for abutting and positioning the rear end of the document (one end in the main scanning direction (arrow X direction), the upper end in FIG. 3). 13 and are provided. A white reference plate 14 is fitted under the positioning member 12.

The contact glass 11 includes a first image reading unit R1 arranged on one side (left side in FIG. 2) of the positioning member 12 in the sub-scanning direction and another side of the positioning member 12 in the sub-scanning direction (right side of FIG. 2). ), and a second image reading unit R2 disposed in (1). In the case of the sheet-through method in which the document Q is automatically conveyed by the document conveying device 6 and is read, the document Q is conveyed to the first image reading unit R1 by the document conveying device 6 and passes through the first image reading unit R1. The image of the document Q is read. On the other hand, in the original fixing method that does not use the original conveying device 6, the original conveying device 6 is opened and closed every time the reading is performed, and the originals are replaced one by one in the second image reading portion R2 of the contact glass 11 to perform the reading.

As shown in FIG. 2, an illumination unit 20 is provided below the contact glass 11, an optical unit 30 capable of reciprocating in the sub-scanning direction, and light reflected from the document Q is reflected and reciprocating in the sub-scanning direction. A movable reflection unit 40, a photoelectric conversion unit 15 having a CCD sensor 16 for receiving light from the reflection unit 40, a drive mechanism 50 having a drive motor 51 for moving the optical unit 30 and the reflection unit 40 in the sub-scanning direction. (See FIG. 14), and the like are provided.

The optical unit 30 has, in addition to the illuminating section 20, a first mirror 31 that directly receives the reflected light emitted from the illuminating section 20 and reflected by the document Q, and reflects the reflected light in a predetermined direction (left direction in FIG. 2). The detailed structure around the illumination unit 20 will be described later.

As shown in FIG. 2, the reflection unit 40 receives the reflected light from the first mirror 31 and reflects it, and receives the reflected light from the second mirror 41 and reflects it toward the photoelectric conversion unit 15. And a third mirror 42.

The photoelectric conversion unit 15 includes a lens group 17 that introduces and collects the reflected light from the reflection unit 40, a CCD sensor 16 that receives the reflected light of the document collected by the lens group 17 and converts the reflected light into an electric signal. And is fixed to the frame 10 a of the image reading device 10.

Here, the illumination unit 20 and the first mirror 31 are integrally fixed to the housing 30a (see FIG. 6) of the optical unit 30, and the second mirror 41 and the third mirror 42 are the housing of the reflection unit 40 ( The optical unit 30 and the reflection unit 40 are independent of each other but are capable of reciprocating in cooperation with each other.

That is, when the document image reading operation is performed by the above-described sheet-through method, the optical unit 30 moves directly below the first image reading unit R1, and the optical path length of the document reflected light is maintained at a predetermined length. On the other hand, in the case of the document fixing method, the optical unit 30 and the reflection unit 40 reciprocate in the second image reading unit R2 while maintaining the optical path length of the document reflected light at the predetermined length.

Under such a configuration, the original reflected light that is emitted from the illumination unit 20 and reflected on the image surface of the original Q is reflected by the first mirror 31, the second mirror 41, and the third mirror 42 and is reflected by the lens group 17. It is introduced, is condensed by the lens group 17, and forms an image on the CCD sensor 16. The CCD sensor 16 converts the received reflected light into an electric signal and outputs it.

Next, the detailed structure of the illumination unit 20 will be described.

The illumination unit 20 is configured by a rod-shaped (here, substantially cylindrical) first light guide member 21 and a second light guide member 22 extending in the main scanning direction, and two light sources 27. The light source 27 includes a light emitting element such as an LED.

As shown in FIG. 2, the first light guide member 21 and the second light guide member 22 are on one side (left side) in the sub-scanning direction with respect to the optical axis L of the light reflected by the document Q and received by the CCD sensor 16. ) And the other side (right side). As shown in FIG. 3, the first light guide member 21 is formed at the light incident surface 21a formed at one end in the main scanning direction (lower end in FIG. 3) and at the other end in the main scanning direction (upper end in FIG. 3). And an opposite surface 21b. The second light guide member 22 has a light incident surface 22a formed at the other end in the main scanning direction (upper end in FIG. 3) and an opposite surface 22b formed at one end in the main scanning direction (lower end in FIG. 3). Have.

A light source 27 is arranged opposite to the light incident surface 21 a of the first light guide member 21 and the light incident surface 22 a of the second light guide member 22. On the opposite surface 21b of the first light guide member 21 and the opposite surface 22b of the second light guide member 22, a reflection sheet 28 made of aluminum tape or the like that reflects light is attached. The light emitted from the light source 27 enters the first light guide member 21 and the second light guide member 22 and is guided in the main scanning direction.

As shown in FIG. 4, each of the first light guide member 21 and the second light guide member 22 has a prism region 23 extending in the main scanning direction at a lower portion (a portion opposite to the document Q) and an upper portion (the document Q). And a light emitting region 25 extending in the main scanning direction.

As shown in FIGS. 4 and 5, the prism area 23 reflects the light emitted from the light source 27 and incident on the light incident surfaces 21 a and 22 a toward the light emitting area 25. The light emitting area 25 emits the light from the prism area 23 toward the document Q.

In the prism area 23, as shown in FIG. 5, a plurality of concave prisms 23a are provided along the main scanning direction. The prism 23a is arranged substantially perpendicular to the main scanning direction and a reflecting surface 23b that is inclined with respect to the main scanning direction and reflects the light incident on the light incident surfaces 21a and 22a toward the light emitting area 25. And a vertical surface 23c. Therefore, the light emitted from the light source 27 and incident on the first light guide member 21 and the second light guide member 22 is reflected by the prism region 23 and emitted from the light emission region 25 toward the document Q.

Here, in the present embodiment, as shown in FIGS. 6 and 7, in the optical unit 30, the light emitted from the illumination unit 20 is disposed between the illumination unit 20 and the contact glass 11 (see FIG. 4). A flat prism sheet 70 that changes the traveling direction to change the incident angle of light with respect to the document Q, and a sheet moving mechanism 90 that moves the prism sheet 70 are provided. Note that in FIG. 7, the prism sheet 70 is indicated by a chain double-dashed line to facilitate understanding.

As shown in FIGS. 8 and 9, the prism sheet 70 is disposed between the first light guide member 21 and the contact glass 11, and changes the traveling direction of the light emitted from the first light guide member 21. It includes a sheet 71 and a second sheet 72 that is disposed between the second light guide member 22 and the contact glass 11 and that changes the traveling direction of the light emitted from the second light guide member 22.

A plurality of convex prisms 75 (see FIG. 10) that change the traveling direction of light (refract light) are formed on substantially the entire upper surfaces of the first sheet 71 and the second sheet 72. The prism 75 is an example of the “prism” in the present invention.

As shown in FIGS. 8 and 10, the prism 75 has a first inclined surface 75a that is inclined with respect to the sub scanning direction. As a result, the incident angle of the light incident on the document Q is changed when viewed from the sub-scanning direction. Here, when viewed from the sub-scanning direction, the incident angle of the light incident on the document Q becomes large (see FIGS. 4 and 8). In the first sheet 71 and the second sheet 72, as shown in FIG. 8, the inclination direction of the first inclined surface 75a of the prism 75 is symmetrical with the sub-scanning direction.

Further, as shown in FIGS. 9 and 11, the prism 75 has a second inclined surface 75b that is inclined with respect to the main scanning direction. As a result, the incident angle of the light incident on the document Q is changed when viewed from the main scanning direction. Here, when viewed from the main scanning direction, the incident angle of the light incident on the document Q becomes large (see FIGS. 12 and 13). In the first sheet 71 and the second sheet 72, as shown in FIG. 9, the inclination direction of the second inclined surface 75b of the prism 75 is symmetrical to the main scanning direction.

The first sheet 71 and the second sheet 72 are angle changing positions (positions in FIG. 8) where the sheet moving mechanism 90 changes the traveling direction of the light emitted from the illumination unit 20 to change the incident angle of the light with respect to the document Q. And a retracted position (position in FIG. 4) that does not change the traveling direction of the light emitted from the illumination unit 20 and does not change the incident angle of the light with respect to the document Q. The first sheet 71 is moved to one side (left side in FIG. 8) in the sub-scanning direction from the angle changing position to be placed in the retracted position, and the second sheet 72 is placed in the sub-scanning direction from the angle changing position. By being moved to the other side (right side in FIG. 8), it is arranged at the retracted position.

Further, as shown in FIG. 4, the optical axis of the light traveling from the first light guide member 21 to the document Q and the light traveling from the second light guide member 22 to the document Q in the state where the prism sheet 70 is arranged at the retracted position. The intersection P23 with the optical axis of is arranged on the upper surface of the contact glass 11 or at a position slightly above the upper surface of the contact glass 11. On the other hand, as shown in FIG. 8, when the prism sheet 70 is arranged at the angle changing position, the optical axis of the light traveling from the first light guide member 21 to the document Q and from the second light guide member 22 to the document Q. An intersection P24 with the optical axis of the traveling light is arranged at a position below the lower surface of the contact glass 11 by a predetermined distance. Therefore, the distance L23 (see FIG. 4) between the intersection P23 and the upper surface of the contact glass 11 is shorter than the distance L24 (see FIG. 8) between the intersection P24 and the upper surface of the contact glass 11.

As shown in FIG. 6, the sheet moving mechanism 90 includes holding members 91a and 91b, biasing members 92a and 92b, wires 93a and 93b, a take-up pulley 94, and a take-up drive motor 95. ..

The holding members 91a and 91b hold the first sheet 71 and the second sheet 72, respectively.

The biasing members 92a and 92b are tension springs. One ends of the biasing members 92a and 92b are attached to the holding members 91a and 91b, respectively, and the other ends of the biasing members 92a and 92b are attached to the housing 30a of the optical unit 30. The urging members 92a and 92b urge the holding members 91a and 91b in the direction from the angle changing position toward the retracted position (outward in the sub-scanning direction).

One ends of the wires 93a and 93b are attached to the holding members 91a and 91b, respectively. The other ends of the wires 93a and 93b are wound around a winding pulley 94. The winding pulley 94 winds the wires 93a and 93b, so that the wires 93a and 93b move the first sheet 71 and the second sheet 72 from the retracted position to the angle changing position against the biasing force of the biasing members 92a and 92b. In the sub scanning direction (inward in the sub-scanning direction).

As shown in FIGS. 6 and 7, the biasing members 92a and 92b, the wires 93a and 93b, and the take-up pulley 94 are provided one on each side in the main scanning direction. The pair of winding pulleys 94 are fixed to both ends of one rotating shaft 96. A pulley 97 is fixed to the rotating shaft 96. A belt 98 that transmits a rotational force is wound around the pulley 97 and the pulley 95a of the winding drive motor 95. When the winding drive motor 95 rotates normally and reversely, the rotation shaft 96 rotates normally and reversely. The first sheet 71 and the second sheet 72 move in the sub scanning direction. The take-up pulley 94, the take-up drive motor 95, the rotary shaft 96, the pulley 97, and the belt 98 constitute a take-up device for taking up the wires 93a and 93b.

FIG. 14 is a block diagram showing an example of a control path of the image reading device 10. As shown in FIG. 14, the control unit (movement control unit) 80 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like, and an operation panel (acquisition unit). It is configured to receive an input signal from 60. The control unit 80 controls the entire image reading device 10. The control unit 80 may be capable of communicating with a main body control unit (not shown) that controls the image forming apparatus 100, and may be configured to control only the image reading apparatus 10 or the image forming apparatus. It may be configured to also serve as a main body control unit that controls the apparatus 100.

For example, the control unit 80 transmits a control signal to the drive motor 51 of the drive mechanism 50 according to the set program to control the drive of the optical unit 30 and the reflection unit 40, and also controls the light emission timing of the light source 27 of the illumination unit 20. Control. Further, the control unit 80 controls the driving of the sheet moving mechanism 90 by transmitting a control signal to the winding drive motor 95 of the sheet moving mechanism 90 according to the set program. Further, the control unit 80 creates image data by subjecting the electric signal from the CCD sensor 16 to resolution processing, scaling processing or gradation processing as necessary.

Information on the type of document Q is input to the operation panel 60 by the user. Specifically, the user inputs information regarding the size of the document Q on the operation panel 60. Further, on the operation panel 60, a normal reading mode for reading an image of a document Q or the like having no surface unevenness is executed, or the unevenness of a document Q or the like having surface unevenness (for example, a credit card or a braille document) and The user inputs whether to execute the emboss reading mode for reading an image. Then, the operation panel 60 transmits the acquired information to the control unit 80.

In the image reading apparatus 10, when executing the normal reading mode, the control unit 80 arranges the prism sheet 70 at the retracted position. As a result, as shown in FIGS. 4 and 5, since the document Q and the like are illuminated from the front direction (direction with a small incident angle), even when the document Q and the like have wrinkles or folds, It is possible to suppress the generation of shadows.

On the other hand, when executing the emboss reading mode, the control unit 80 arranges the prism sheet 70 at the angle changing position. As a result, as shown in FIGS. 8 and 9, the document Q or the like (for example, a credit card or Braille document) is illuminated from an oblique direction (direction with a large incident angle), so that a shadow corresponding to the unevenness of the document Q or the like is generated. As a result, the unevenness of the document Q or the like and the image can be read.

When the document Q or the like having unevenness on the surface is illuminated from an oblique direction, the illumination light is deviated from the optical axis by the level difference of the unevenness. At this time, since the incident angle of light with respect to the document Q and the like is large, the amount of deviation (deviation angle) of the illumination light from the optical axis becomes large, and the amount of irradiation light decreases. Therefore, a shadow corresponding to the unevenness is generated.

In the present embodiment, as described above, the prism sheet 70 has an angle changing position where the sheet moving mechanism 90 changes the traveling direction of the light emitted from the illumination unit 20 to change the incident angle of the light with respect to the document Q and the like. , And the retracted position where the traveling direction of the light emitted from the illumination unit 20 is not changed and the incident angle of the light with respect to the document Q or the like is not changed. As a result, even when the document Q or the like has wrinkles or folds, it is possible to prevent the shadow from being generated by irradiating the document Q or the like with light from the front direction. Images such as Q can be read. Further, by irradiating the document Q or the like with light from an oblique direction, a shadow is generated in accordance with the irregularity of the document Q or the like, so that the irregularity can be read.

Further, since the plate-shaped prism sheet 70 is arranged between the illumination section 20 and the contact glass 11, the image reading device is different from the conventional image reading device in which the reflecting plate curved in a concave shape is arranged above the light source. It is possible to prevent the 10 from becoming large in the vertical direction.

The first light guide member 21 and the second light guide member 22 that extend in the main scanning direction and emit light toward the document Q while guiding light along the main scanning direction are used to illuminate the document Q and the like. Therefore, unlike the case where a document is directly illuminated by a plurality of light sources arranged along the main scanning direction (for example, in the case of the conventional image reading apparatus described above), the document Q or the like can be uniformly illuminated in the main scanning direction. it can.

Further, as described above, in the normal reading mode for reading the image of the document Q or the like, the control unit 80 arranges the prism sheet 70 at the retracted position and reads the unevenness of the document Q or the like having unevenness on the surface and the emboss reading. In the mode, the prism sheet 70 is arranged at the angle changing position. Thus, in the normal reading mode, the original Q and the like can be easily irradiated with light from the front side, so that the image of the original Q and the like can be easily read. Further, in the emboss reading mode, the original Q and the like can be easily irradiated with light from an oblique direction, so that the unevenness can be easily read.

Further, as described above, in the normal reading mode, the intersection P23 between the optical axis of the light traveling from the first light guide member 21 to the original Q and the like and the optical axis of the light traveling from the second light guide member 22 to the original Q and the like, The distance L23 between the upper surface of the contact glass 11 and the optical axis of the light traveling from the first light guide member 21 to the original Q or the like in the emboss reading mode and the optical axis of the light traveling from the second light guide member 22 to the original Q or the like. Is shorter than the distance L24 between the intersection point P24 and the upper surface of the contact glass 11. As a result, in the embossed reading mode (the state in which the prism sheet 70 is arranged at the angle changing position), it is possible to increase the decrease in the irradiation light amount according to the step (height) of the unevenness of the document Q or the like, and thus the document Q or the like It is possible to further generate a shadow corresponding to the unevenness of the. Therefore, the unevenness can be read more easily.

Further, as described above, the prism sheet 70 is provided with a plurality of prisms 75 having the first inclined surface 75a inclined with respect to the sub-scanning direction. This makes it possible to easily change the incident angle of the light incident on the document Q or the like when viewed from the sub-scanning direction.

Further, as described above, the prism 75 has the second inclined surface 75b inclined with respect to the main scanning direction. This makes it possible to easily change the incident angle of the light incident on the document Q or the like when viewed from the main scanning direction.

Further, as described above, the first sheet 71 is placed in the retracted position by being moved from the angle changing position to one side in the sub-scanning direction, and the second sheet 72 is placed in the other position in the sub-scanning direction from the angle changing position. By being moved to the side, it is arranged at the retracted position. Thereby, compared with the case where both the first light guide member 21 and the second light guide member 22 are moved from the angle changing position to, for example, one side in the sub-scanning direction, the first light guide member 21 and the second light guide member 22. 22 can be moved to the angle changing position and the retracted position with a small movement distance.

In addition, as described above, the sheet moving mechanism 90 moves the prism sheet 70 in the direction from the angle changing position to the retracted position and the biasing members 92a and 92b that move the prism sheet 70 from the retracted position to the angle changed position. It has wires 93a and 93b and a winding device (winding pulley 94, winding drive motor 95, rotating shaft 96, pulley 97, belt 98) for winding the wires 93a and 93b. Accordingly, the prism sheet 70 can be easily moved to the angle changing position and the retracted position.

It should be understood that the embodiments disclosed this time are exemplifications in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of the claims, and further includes meanings equivalent to the scope of the claims and all modifications within the scope.

For example, as the image forming apparatus in which the image reading apparatus of the present invention is mounted, only a digital multi-function peripheral is shown here, but the present invention is not limited to the analog type copying machine or color copying machine. Alternatively, it is of course applicable to an image scanner separate from the image forming apparatus.

Further, in the above embodiment, the incident angle of light with respect to the document Q or the like when the prism sheet 70 is arranged at the angle changing position is the incident angle of light with respect to the document Q or the like when the prism sheet 70 is arranged at the retracted position. However, the present invention is not limited to this. The incident angle of light with respect to the document Q or the like when the prism sheet 70 is arranged at the angle changing position may be smaller than the incident angle of light with respect to the document Q or the like when the prism sheet 70 is arranged at the retracted position. .. In this case, the prism sheet 70 may be placed at the angle changing position in the normal reading mode, and the prism sheet 70 may be placed in the retracted position in the emboss reading mode.

3 image forming part 10 image reading device 11 contact glass 16 CCD sensor (photoelectric conversion part)
20 illumination unit 21 first light guide member 21a, 22a light incident surface 22 second light guide member 27 light source 70 prism sheet 71 first sheet 72 second sheet 75 prism 75a first inclined surface 75b second inclined surface 80 control unit ( Movement control unit)
90 sheet moving mechanism 92a, 92b biasing member 93a, 93b wire 100 image forming apparatus L optical axis L23, L24 distance P23, P24 intersection Q document (read object)

Claims (8)

A contact glass on which the object to be read is placed,
An illumination unit arranged below the contact glass and irradiating the object to be read with light.
A photoelectric conversion unit that receives reflected light from the object to be read, converts the received reflected light into an electric signal, and outputs the electric signal.
A flat prism sheet disposed between the illumination unit and the contact glass, and changing the traveling direction of the light emitted from the illumination unit to change the incident angle of the light with respect to the object to be read,
A sheet moving mechanism for moving the prism sheet,
Equipped with
The lighting unit is
While extending in the main scanning direction, they are arranged on one side and the other side of the sub-scanning direction with respect to the optical axis of the light reflected by the object to be read and received by the photoelectric conversion unit, respectively, and direct the light in the main scanning direction. A first light guide member and a second light guide member which are emitted toward the object to be read while being guided along
A light source disposed opposite to a light incident surface formed at one end of the first light guide member in the main scanning direction and at the other end of the second light guide member in the main scanning direction,
Have
The prism sheet is configured to change the traveling direction of the light emitted from the illumination unit by the sheet moving mechanism to change the incident angle of the light with respect to the object to be read, and an angle changing position of the light emitted from the illumination unit. An image reading apparatus, wherein the image reading apparatus is selectively arranged at a retracted position where the traveling direction is not changed and the incident angle of light with respect to the object to be read is not changed. Further comprising a movement control unit for controlling the seat moving mechanism,
The incident angle of light with respect to the object to be read when the prism sheet is arranged at the angle changing position is larger than the incident angle of light with respect to the object to be read when the prism sheet is arranged at the retracted position. ,
The movement control unit,
In the normal reading mode for reading the image of the object to be read, the prism sheet is arranged at the retracted position,
The image reading apparatus according to claim 1, wherein the prism sheet is arranged at the angle changing position in an emboss reading mode in which the image of the unevenness of the object to be read and the image having unevenness on the surface are read. In the normal reading mode, an intersection of an optical axis of light traveling from the first light guide member to the object to be read and an optical axis of light traveling from the second light guide member to the object to be read, and an upper surface of the contact glass And the distance between and is the intersection of the optical axis of light traveling from the first light guide member to the object to be read and the optical axis of light traveling from the second light guide member to the object in the emboss reading mode. The image reading apparatus according to claim 2, wherein the distance is shorter than the distance between the contact glass and the upper surface of the contact glass. The image reading apparatus according to claim 1, wherein the prism sheet is provided with a plurality of prisms each having a first inclined surface that is inclined with respect to the sub-scanning direction. The image reading apparatus according to claim 4, wherein the prism further includes a second inclined surface that is inclined with respect to the main scanning direction. The prism sheet is disposed between the first light guide member and the contact glass, and changes the traveling direction of the light emitted from the first light guide member, and the second light guide member. A second sheet that is disposed between the contact glass and changes a traveling direction of light emitted from the second light guide member,
The first sheet is arranged at the retracted position by being moved from the angle changing position to one side in the sub-scanning direction,
The image according to any one of claims 1 to 5, wherein the second sheet is arranged at the retracted position by being moved from the angle changing position to the other side in the sub-scanning direction. Reader. The sheet moving mechanism includes a biasing member that biases the prism sheet in a direction from the angle changing position toward the retracted position, and the prism sheet from the retracted position against the biasing force of the biasing member. The image reading device according to claim 1, further comprising: a wire that moves in a direction toward the angle changing position; and a winding device that winds the wire. An image reading apparatus according to any one of claims 1 to 7,
An image forming unit that forms an image on a recording medium based on image data read by the image reading device;
An image forming apparatus comprising: