WO2016199261A1

WO2016199261A1 - Image reading device

Info

Publication number: WO2016199261A1
Application number: PCT/JP2015/066797
Authority: WO
Inventors: 翔吾宮野; 高畠　昌尚; 暁岩山
Original assignee: 株式会社Pfu
Priority date: 2015-06-10
Filing date: 2015-06-10
Publication date: 2016-12-15
Also published as: JPWO2016199261A1; JP6349034B2

Abstract

In order to easily change a light irradiation direction according to a reading position by a simple configuration, an image reading device is provided with: a line sensor 31 which linearly reads a medium P mounted on a mounting surface 11 in a main scanning direction of the mounting surface 11; a rotating mirror 51 which reflects and rotates a sensor optical axis S of the line sensor 31 to thereby move the sensor optical axis S in a sub-scanning direction of the mounting surface 11 with respect to the mounting surface 11; an illumination part 60 which irradiates at least a reading region of the line sensor 31 with light, and rotates in conjunction with the movement of the reading region; a rotating motor 55 which rotates the rotating mirror 51 and the illumination part 60; and a speed ratio conversion mechanism 80 which sets the rotation speed ratio between the rotating mirror 51 and the illumination part 60 to 1:2. A mirror rotating shaft 53 of the rotating mirror 51 coincides with a reflection surface 52 of the rotating mirror 51 and an illumination rotation axis L of the illumination part 60 when viewed from the main scanning direction, and the illumination part 60 applies light in a direction in which an illumination optical axis L coincides with the sensor optical axis S reflected by the reflection surface 52.

Description

Image reading device

This disclosure relates to an image reading apparatus.

Some image reading devices that use an image sensor that converts received light into an electrical signal to capture an image capture the position read by the line sensor using a so-called line sensor in which the image sensors are arranged in a line. Some devices perform reading while moving on a medium in a sub-scanning direction that is a direction orthogonal to the direction in which the elements are arranged. In addition, among image reading apparatuses that perform reading while moving the reading position in the sub-scanning direction in this way, the line sensor is enlarged by rotating a mirror that reflects the optical axis when reading is performed by the line sensor. There is one that moves the reading position on the medium without moving (for example, see Patent Documents 1 and 2).

JP 2005-86443 A Japanese Patent Laid-Open No. 9-181887

Here, when reading a medium using a line sensor, a reading position is irradiated by a light source, and light from the light source reflected by the medium is received by the line sensor, thereby obtaining a higher quality image. However, when the reading position is moved in the sub-scanning direction, it is necessary to change the irradiation direction of the light source in the sub-scanning direction in accordance with the movement of the reading position. In this case, a power source such as a drive motor for changing the irradiation direction of the light source is required, and the irradiation direction of the light source needs to be changed in accordance with the movement of the reading position. For this reason, changing the irradiation direction of the light source in accordance with the reading position by the line sensor leads to an increase in the number of parts and the manufacturing process, which causes a rise in manufacturing cost.

The present disclosure has been made in view of the above, and an object of the present disclosure is to provide an image reading apparatus that can easily change the irradiation direction of light according to a reading position with a simple configuration.

In order to solve the above-described problems and achieve the object, an image reading apparatus according to the present disclosure includes a line sensor that reads a medium placed on a placement surface in a line shape in the main scanning direction of the placement surface; A rotating mirror that reflects and rotates the sensor optical axis of the line sensor to move the sensor optical axis in a sub-scanning direction perpendicular to the main scanning direction on the mounting surface with respect to the mounting surface; Illuminating at least the reading area of the line sensor and rotating in conjunction with the movement of the reading area in the sub-scanning direction; and the rotating mirror and the illuminating part in parallel with the main scanning direction. Speed ratio conversion with a rotation speed ratio of 1: 2 between a rotary actuator that rotates about a rotation axis, the rotating mirror that rotates by a rotational force from the rotary actuator, and the illumination unit And the rotation axis of the rotating mirror coincides with the reflecting surface of the rotating mirror or an extension line of the reflecting surface when viewed from the main scanning direction, and illumination of the illumination unit The illumination unit coincides with the rotation axis, and the illumination unit reflects the illumination optical axis of the light emitted from the illumination unit in the main scanning direction with respect to the sensor optical axis reflected by the reflection surface of the rotation mirror. Irradiate light in the matching direction.

The image reading apparatus according to the present disclosure has an effect that the light irradiation direction can be easily changed according to the reading position with a simple configuration.

FIG. 1 is a perspective view of an image reading apparatus according to an embodiment. FIG. 2 is an AA arrow view of FIG. FIG. 3 is a schematic diagram showing the configuration of the image reading apparatus shown in FIG. FIG. 4 is a detailed view of part C of FIG. FIG. 5 is a schematic diagram showing the positional relationship between the illumination unit and the rotating mirror. 6 is a DD arrow view of FIG. FIG. 7 is a perspective view of the rotating mirror shown in FIG. FIG. 8 is a view taken along the line EE in FIG. FIG. 9 is a block diagram illustrating a main configuration of the image reading apparatus according to the embodiment. FIG. 10 is a schematic diagram of a speed ratio conversion mechanism. FIG. 11 is an explanatory diagram showing a state at the start of reading. FIG. 12 is an explanatory diagram showing a state at the end of reading. FIG. 13 is an explanatory diagram showing a state where the sensor optical axis and the illumination optical axis do not match. FIG. 14 is an explanatory diagram for reading a thick medium with the image reading apparatus shown in FIG. FIG. 15 is a modified example of the image reading apparatus according to the embodiment, and is an explanatory diagram when the mirror rotation axis is located above the reflection position of the sensor optical axis. FIG. 16 is a modified example of the image reading apparatus according to the embodiment, and is an explanatory diagram when the mirror rotation axis is located below the reflection position of the sensor optical axis. FIG. 17 is a modified example of the image reading apparatus according to the embodiment, and is an explanatory diagram when the mirror rotation axis is located at a position other than the reflection position of the sensor optical axis. FIG. 18 is a modified example of the image reading apparatus according to the embodiment, and is an explanatory diagram when the illumination rotation axis is located on a position other than the illumination optical axis. FIG. 19 is a modified example of the image reading apparatus according to the embodiment, and is an explanatory diagram showing a state where the mirror rotation axis is located at a position other than the reflection position of the sensor optical axis and coincides with the illumination rotation axis. FIG. 20 is an explanatory diagram when the mirror rotation axis and the illumination rotation axis are located at the reflection position of the sensor optical axis on the reflection surface and the sensor optical axis and the illumination optical axis coincide with each other. FIG. 21 is an explanatory diagram when the mirror rotation axis and the illumination rotation axis are positioned above the reflection position of the sensor optical axis on the reflection surface and the sensor optical axis and the illumination optical axis coincide with each other. FIG. 22 is an explanatory diagram when the mirror rotation axis and the illumination rotation axis are positioned below the reflection position of the sensor optical axis on the reflection surface and the sensor optical axis and the illumination optical axis coincide with each other. FIG. 23 is an explanatory diagram in the case where the mirror rotation axis and the illumination rotation axis are located on the extension line of the reflecting surface and the sensor optical axis and the illumination optical axis coincide with each other. FIG. 24 is an explanatory diagram of each coordinate when the angle of the rotating mirror is 45 °. FIG. 25 is an explanatory diagram of each coordinate of the illumination optical axis. FIG. 26 is a modification of the image reading apparatus according to the embodiment, and is a detailed view of an illumination unit in which a mirror is used. FIG. 27 is a schematic diagram of the speed ratio conversion mechanism in the case where power is transmitted to the illumination unit via the rotating mirror, which is a modification of the image reading apparatus according to the embodiment. FIG. 28 is a modification of the image reading apparatus according to the embodiment, and is a schematic diagram of a speed ratio conversion mechanism in the case where power is transmitted to a rotating mirror via an illumination unit. FIG. 29 is a modification of the image reading apparatus according to the embodiment, and is a schematic diagram of a speed ratio conversion mechanism when power is transmitted through different paths between the rotating mirror and the illumination unit. FIG. 30 is a modified example of the image reading apparatus according to the embodiment, and is an explanatory diagram when a plurality of reading units are provided.

Hereinafter, embodiments of an image reading apparatus according to the present disclosure will be described in detail based on the drawings. In addition, this invention is not limited by this embodiment. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same.

Embodiment
FIG. 1 is a perspective view of an image reading apparatus according to an embodiment. FIG. 2 is an AA arrow view of FIG. The image reading apparatus 1 shown in FIGS. 1 and 2 is an apparatus that reads the medium P by imaging the medium P from above. The image reading apparatus 1 includes a mounting table 10 on which a medium P is placed and a reading unit 20 that reads the medium P. The mounting table 10 is formed in a rectangular plate shape, and a mounting surface 11 on which the medium P is mounted is provided on the upper surface side. The reading unit 20 is disposed on the upper side of the mounting table 10, that is, on the upper side of the mounting surface 11, and is connected by an arm 15 that extends substantially in the vertical direction. The lower end side of the arm 15 is connected to the mounting table 10 and the upper end side is connected to the reading unit 20, so that the mounting table 10 and the reading unit 20 protrude in the same direction side with respect to the arm 15 in the horizontal direction. The arm 15 is connected to the mounting table 10 and the reading unit 20. The mounting table 10 and the reading unit 20 are arranged to face each other in the vertical direction by connecting the arm 15 in this way.

The reading unit 20 disposed to face the mounting table 10 is provided with an illumination unit 60 that can emit light toward the mounting surface 11 when the reading unit 20 reads the medium P. The illumination unit 60 is provided at two locations of the reading unit 20. When the reading unit 20 is viewed in the vertical direction, the two illumination units 60 are located at positions other than the portion where the arm 15 is connected in the reading unit 20 and at positions opposite to each other in the horizontal direction. Projecting in opposite directions to each other.

FIG. 3 is a schematic diagram showing the configuration of the image reading apparatus shown in FIG. The reading unit 20 includes a first optical unit 30 that reads the medium P, a second optical unit 40 that turns back the optical axis when the first optical unit 30 performs reading, and light that is turned back by the second optical unit 40. A third optical unit 50 that reflects the axis toward the mounting surface 11 of the mounting table 10. The first optical unit 30, the second optical unit 40, and the third optical unit 50 are all installed in the housing 21 of the reading unit 20.

Among these, the first optical unit 30 includes a line sensor 31 and a condenser lens 35 and is fixed to the housing 21, and the line sensor 31 places the medium P placed on the placement surface 11. The surface 11 can be read in a line shape in the main scanning direction. Note that the main scanning direction in this case refers to the direction in which the imaging elements are arranged in the line sensor 31 formed by arranging a plurality of imaging elements that capture an image. That is, the line sensor 31 can read the imaging target in a line shape by arranging a plurality of imaging elements in a linear shape. That is, the line sensor 31 having a plurality of image sensors can generate image data by converting light received by the image sensors into electronic data by photoelectric conversion.

The condensing lens 35 is disposed on the sensor optical axis S that is an optical axis when the line sensor 31 performs imaging, and the light that travels along the sensor optical axis S toward the line sensor 31 is transmitted to the line sensor 31. It is possible to form an image on 31 image sensors. The line sensor 31 receives the imaged light, and outputs an electric signal corresponding to the received light, thereby generating line-shaped image data in the main scanning direction. Note that the number of lines of the image sensor included in the line sensor 31 may be single or plural. In addition, since the line sensor 31 performs imaging using an imaging device in which a plurality are arranged in the main scanning direction, the sensor optical axis S when the line sensor 31 performs imaging is an optical axis that spreads in a plane in the main scanning direction. Yes.

The second optical unit 40 can turn back the sensor optical axis S by 180 ° when the line sensor 31 of the first optical unit 30 performs reading. FIG. 4 is a detailed view of part C of FIG. Specifically, the second optical unit 40 includes a pair of folding mirrors 42 and a carrier 41 that holds the folding mirrors 42. The folding mirror 42 is located on the sensor optical axis S from the first optical unit 30, and the first optical unit side mirror 43 reflecting the sensor optical axis S and the sensor light reflected by the first optical unit side mirror 43. And a third optical unit side mirror 44 which is located on the axis S and reflects the sensor optical axis S toward the third optical unit 50.

Among these, the first optical unit side mirror 43 is installed such that the reflection surface is inclined at an angle of 45 ° with respect to the sensor optical axis S, and thus the first optical unit side mirror 43 is configured to be the first optical unit. The sensor optical axis S from the unit 30 can be reflected by changing the direction of 90 °. Specifically, the first optical unit side mirror 43 can reflect the sensor optical axis S from the first optical unit 30 by changing the direction of 90 ° downward.

The third optical unit side mirror 44 is disposed below the first optical unit side mirror 43, and reflects the sensor optical axis S reflected downward by the first optical unit side mirror 43. The surface is installed so as to be inclined at an angle of 45 °. Accordingly, the third optical unit side mirror 44 can reflect the sensor optical axis S reflected by the first optical unit side mirror 43 by changing the direction by 90 °.

At that time, the third optical unit side mirror 44 can reflect the sensor optical axis S reflected by the first optical unit side mirror 43 to the side where the first optical unit 30 is located. . For this reason, the second optical unit 40 having the folding mirror 42 composed of the first optical unit side mirror 43 and the third optical unit side mirror 44 can fold the sensor optical axis S from the first optical unit 30 by 180 °. It is possible. The second optical unit 40 configured as described above is provided in the housing 21 so as to be movable in the optical axis direction between the first optical unit 30 and the second optical unit 40. That is, the moving direction of the second optical unit 40 is a direction facing the mounting surface 11 of the mounting table 10 when viewed from the main scanning direction, in other words, the moving direction of the second optical unit 40. Is in a direction parallel to the mounting surface 11.

FIG. 5 is a schematic diagram showing the positional relationship between the illumination unit and the rotating mirror. 6 is a DD arrow view of FIG. FIG. 7 is a perspective view of the rotating mirror shown in FIG. FIG. 8 is a view taken along the line EE in FIG. The third optical unit 50 rotates the sensor optical axis S folded by the second optical unit 40, so that the sensor optical axis S is orthogonal to the main scanning direction on the mounting surface 11 with respect to the mounting surface 11. It can be moved in the sub-scanning direction. The third optical unit 50 is positioned in the sub-scanning direction between the first optical unit 30 and the second optical unit 40 in the same direction. Specifically, the third optical unit 50 has a rotating mirror 51 that reflects the sensor optical axis S folded back by the second optical unit 40. The rotating mirror 51 is disposed on the sensor optical axis S folded back by the second optical unit 40, and the reflecting surface 52 is disposed on the second optical unit 40 side and in a direction facing the lower side. Has been. Accordingly, the rotating mirror 51 can reflect the sensor optical axis S folded back by the second optical unit 40 downward.

The rotating mirror 51 is rotatable about a mirror rotating shaft 53 that is a rotating shaft extending in the main scanning direction, and the mirror rotating shaft 53 is provided on the reflecting surface 52 of the rotating mirror 51. It has been. The mirror rotation axis 53 coincides with the reflection surface 52 of the rotation mirror 51 when viewed from the main scanning direction, and the sensor optical axis S folded back by the second optical unit 40 on the reflection surface 52 of the rotation mirror 51 is obtained. It is provided so as to be located in the vicinity of the reflecting position. That is, the mirror rotation axis 53 coincides with the position where the sensor optical axis S is reflected on the reflection surface 52 when viewed from the main scanning direction. Specifically, the mirror rotation shafts 53 are positioned at both ends of the rotation mirror 51 in the main scanning direction and extend in the main scanning direction, respectively. The axis of the mirror rotation shaft 53 positioned at both ends of the rotation mirror 51 is rotated. It is located on the reflection surface 52 of the mirror 51. The third optical unit 50 can move the reflection direction of the sensor optical axis S reflected by the rotation mirror 51 in the sub-scanning direction by rotating the rotation mirror 51 around the mirror rotation axis 53.

Further, the rotating mirror 51 is installed in a direction capable of reflecting the sensor optical axis S on the side where the second optical unit 40 is positioned in the sub-scanning direction from the position below the rotating mirror 51 in the vertical direction. . Accordingly, the third optical unit 50 moves the sensor optical axis S in the sub-scanning direction within a range not including the position where the angle of the sensor optical axis S with respect to the placement surface 11 when viewed from the main scanning direction is 90 °. It can be moved.

An opening 25 through which the sensor optical axis S between the third optical unit 50 and the placement surface 11 passes is formed in the housing 21 of the reading unit 20. The opening 25 is formed in the vicinity of the third optical unit 50 on the lower surface side of the housing 21 and faces the mounting surface 11. As a result, the opening 25 rotates even when the sensor optical axis S reflected by the rotating mirror 51 is positioned in any part of the moving range when the rotating mirror 51 moves in the sub-scanning direction. The sensor optical axis S between the mirror 51 and the mounting surface 11 can be passed. The third optical unit 50 provided in the reading unit 20 can reflect the sensor optical axis S folded back by the second optical unit 40 toward the placement surface 11 by passing through the opening 25. it can.

Illumination units 60 provided at two locations of the reading unit 20 are respectively disposed near both ends of the third optical unit 50 in the main scanning direction. Each of these illumination units 60 includes a light emitting unit 61 such as an LED (Light Emitting Diode), and a lens 62 that can irradiate light emitted from the light emitting unit 61 in a line shape. Thereby, the illumination unit 60 can irradiate the medium P with line-shaped light. Specifically, the illuminating unit 60 is directed to the mounting surface 11 along the sensor optical axis S that reflects light that is linear in the main scanning direction from the third optical unit 50 toward the mounting surface 11. Irradiation is possible. That is, the illuminating unit 60 aligns the illumination optical axis L of the light emitted from the illuminating unit 60 with the sensor optical axis S reflected by the reflecting surface 52 of the rotating mirror 51 when viewed in the main scanning direction. Irradiate light.

Further, the illumination unit 60 can rotate around an illumination rotation axis 63 that is a rotation axis of the illumination unit 60, and the illumination rotation axis 63 is oriented to extend in the main scanning direction. The illumination rotation axis 63 is disposed on the illumination optical axis L, that is, the illumination unit 60 is disposed on the illumination optical axis L when viewed from the main scanning direction. Thereby, when the illumination unit 60 rotates around the illumination rotation axis 63, the illumination optical axis L also rotates around the illumination rotation axis 63. For this reason, the illumination unit 60 can move the illumination optical axis L in the sub-scanning direction with respect to the placement surface 11 by rotating around the illumination rotation axis 63. It is possible to move the line-shaped light emitted from the mounting surface 11 in the sub-scanning direction of the mounting surface 11.

Further, in the illumination unit 60 that is rotatably provided in this way, the illumination rotation axis 63 is coaxial with the mirror rotation axis 53 of the third optical unit 50. That is, the illumination rotation shaft 63 of the illumination unit 60 is located on the extension line of the mirror rotation shaft 53 of the third optical unit 50 extending in the main scanning direction, and when viewed from the main scanning direction, the illumination rotation shaft 63 and The mirror rotation axes 53 coincide. For this reason, the illumination unit 60 can rotate around the illumination rotation axis 63 that is coaxial with the mirror rotation axis 53 of the rotation mirror 51 of the third optical unit 50.

At that time, the illumination unit 60 can rotate at a rotational speed twice that of the rotary mirror 51. Thereby, even when the sensor optical axis S reflected by the rotary mirror 51 moves in the sub-scanning direction in accordance with the rotation of the rotary mirror 51, the illumination unit 60 rotates around the illumination rotary axis 63, thereby The axis L can be moved along the sensor optical axis S along with the sensor optical axis S in the sub-scanning direction. In other words, the illumination unit 60 can irradiate at least the reading area of the line sensor 31 and rotate in conjunction with the movement of the reading area in the sub-scanning direction.

FIG. 9 is a block diagram illustrating a main configuration of the image reading apparatus according to the embodiment. In addition to the first optical unit 30, the second optical unit 40, the third optical unit 50, and the illumination unit 60, the reading unit 20 is provided with a U-turn motor 45, a rotation motor 55, and a speed ratio conversion mechanism 80. . Among these, the U-turn motor 45 is a moving actuator that moves the second optical unit 40 relative to the first optical unit 30 in the optical axis direction between the first optical unit 30 and the second optical unit 40. Is provided. That is, the U-turn motor 45 moves the second optical unit 40 close to or away from the first optical unit 30 by moving the second optical unit 40 along the optical axis direction between the first optical unit 30 and the second optical unit 40. It is possible to do.

The rotation motor 55 is provided as a rotation actuator that rotates the rotation mirror 51 and the illumination unit 60 of the third optical unit 50 around the mirror rotation axis 53 and the illumination rotation axis 63 parallel to the main scanning direction. Further, the speed ratio conversion mechanism 80 sets the rotation speed ratio between the rotating mirror 51 rotated by the rotating force from the rotating motor 55 and the illumination unit 60 to 1: 2, and the power generated by the rotating motor 55 with the rotating mirror 51. Transmission to the illumination unit 60 is possible. That is, among the rotary mirror 51 and the illumination unit 60 that are both rotated by the power transmitted from the rotary motor 55, the illumination unit 60 rotates with a change amount that is twice the change amount of the rotation angle of the rotary mirror 51. do.

The image reading apparatus 1 also includes a control circuit 70. The control circuit 70 is a CPU (Central Processing Unit) that functions as a controller that executes various processes, and a RAM (Random) that functions as a memory that stores various information. The computer has an Access Memory (ROM) and a ROM (Read Only Memory). All or part of each function of the control circuit 70 is realized by reading and writing data in the RAM or ROM by loading an application program held in the ROM into the RAM and executing it by the CPU. .

The control circuit 70 controls the line sensor 31 included in the first optical unit 30 to read an image, a motor control unit 72 that controls the U-turn motor 45 and the rotation motor 55, and an illumination unit 60. And an illumination control unit 73 that controls turning on and off. The control circuit 70 includes an image processing unit 74 that performs image processing of an image read by the image reading control unit 71 and a storage unit 75 that stores various types of information such as read image information. Furthermore, the control circuit 70 includes a communication unit 76 that communicates with an external device. The communication unit 76 is connected to an external device by wire or wireless, and can transmit and receive information. As the external device, for example, a PC (Personal Computer) 100 is used, and the communication unit 76 can communicate with the PC 100.

Further, the image reading apparatus 1 is provided with a scan switch 78 that causes the image reading apparatus 1 to perform a reading operation. For example, the scan switch 78 is disposed on the top surface of the mounting table 10, and when an input operation is performed by the user, the scan switch 78 transmits the fact to the control circuit 70, thereby reading the image reading apparatus 1. It is possible to make an action take place.

FIG. 10 is a schematic diagram of the speed ratio conversion mechanism. The speed ratio converting mechanism 80 combines the belt 95 that transmits power and a plurality of pulleys around which the belt 95 is wound, so that the power from the rotary motor 55 is changed with the rotation speed ratio and the rotating mirror 51 and the illumination unit. 60. Specifically, the speed ratio conversion mechanism 80 is a relay shaft for transmitting power from the rotary motor 55 to the rotary mirror 51 and the illumination unit 60, and is a drive transmission that is a rotary shaft extending in the main scanning direction. The power from the rotary motor 55 is transmitted to the rotary mirror 51 and the illumination unit 60 via the drive transmission rotary shaft 81. A second pulley 83 for driving transmission is attached to the rotation shaft 81 for driving transmission, and a first pulley 82 for driving transmission is attached to the output shaft of the rotary motor 55. A belt 95 is wound around the pulley 82 and the second pulley 83 for drive transmission.

The speed ratio conversion mechanism 80 needs to transmit the power from the rotary motor 55 to the rotary mirror 51 and the illumination unit 60 at an appropriate speed ratio, and therefore the belt 95 used in the speed ratio conversion mechanism 80. Are all so-called toothed belts, and the pulleys are all toothed pulleys corresponding to the toothed belts.

The power transmitted from the drive transmission rotary shaft 81 to the rotary mirror 51 includes a rotary mirror first pulley 91 attached to the drive transmission rotary shaft 81, a rotary mirror second pulley 92 attached to the rotary mirror 51, and It is transmitted by the belt 95 wound around the first pulley 91 for rotating mirror and the second pulley 92 for rotating mirror. The second pulley 92 for the rotating mirror is attached to one of the mirror rotating shafts 53 disposed at both ends of the rotating mirror 51 in the main scanning direction, and rotates integrally with the rotating mirror 51.

Further, the power transmitted from the drive transmission rotating shaft 81 to the illumination unit 60 includes an illumination first pulley 86 attached to the drive transmission rotation shaft 81, an illumination second pulley 87 attached to the illumination unit 60, and It is transmitted by the belt 95 wound around the first pulley 86 for illumination and the second pulley 87 for illumination. The first illumination pulley 86, the second illumination pulley 87, and the belt 95 are provided corresponding to each of the two illumination units 60 disposed near both ends of the rotary mirror 51 in the main scanning direction. ing. That is, two illumination first pulleys 86 are attached to the drive transmission rotating shaft 81, and the illumination second pulley 87 is attached to each of the two illumination units 60. As described above, each of the two illumination first pulleys 86 and the second illumination pulleys 87 is wound around each. The second illumination pulley 87 is attached to the illumination rotation shaft 63 of the illumination unit 60 and rotates integrally with the illumination unit 60.

The speed ratio converting mechanism 80 configured as described above is such that the ratio of the number of teeth of the second pulley for illumination 87 to the number of teeth of the first pulley for illumination 86 is the rotation mirror for the number of teeth of the first pulley 91 for the rotation mirror. This is 1/2 of the ratio of the number of teeth of the second pulley 92 for use. Thus, the rotational speed ratio when power is transmitted from the rotary motor 55 to the rotary mirror 51 and the illumination unit 60 is 1: 2, and the power is transmitted to the rotary mirror 51 to the illumination unit 60. Power is transmitted at a rotational speed twice that of the rotational speed.

The image reading apparatus 1 according to the present embodiment is configured as described above, and the operation thereof will be described below. FIG. 11 is an explanatory diagram showing a state at the start of reading. In the image reading apparatus 1, the control circuit 70 controls the reading unit 20 when the user performs an input operation on the scan switch 78 with the medium P placed on the placement surface 11 of the placement table 10. Thus, the reading unit 20 is caused to read the medium P. When the reading unit 20 performs a reading operation, the control circuit 70 controls the U-turn motor 45 and the rotation motor 55 by the motor control unit 72, thereby causing the second optical unit 40 and the third optical unit 50 to move. Then, the image reading control unit 71 obtains an image read by the line sensor 31 included in the first optical unit 30 in a reading start state.

Specifically, the control circuit 70 performs drive control of the U-turn motor 45 by the motor control unit 72, so that the second optical unit is located at the position farthest from the first optical unit 30 in the moving direction of the second optical unit 40. The unit 40 is moved. In addition, the control circuit 70 reflects the sensor optical axis S turned back by the second optical unit 40 by the rotary mirror 51 and moves the vertical position of the rotary mirror 51 in the movement range when moving the sensor optical axis S on the mounting surface 11 in the sub-scanning direction. The rotary mirror 51 is rotated at a rotation angle that directs the sensor optical axis S to a position closest to the lower side in the direction. That is, the control circuit 70 performs drive control of the rotation motor 55 by the motor control unit 72, so that the rotation mirror 51 is driven by the power generated by the rotation motor 55 and transmitted to the rotation mirror 51 through the speed ratio conversion mechanism 80. Rotate.

The transmission path of the power generated by the rotary motor 55 will be described. The power generated by the rotary motor 55 is transmitted through the first pulley 82 for driving transmission, the belt 95, and the second pulley 83 for driving transmission included in the speed ratio conversion mechanism 80. The drive transmission rotating shaft 81 is rotated by this power. The power transmitted to the drive transmission rotating shaft 81 is transmitted to the rotating mirror 51 through the first pulley 91 for the rotating mirror, the belt 95, and the second pulley 92 for the rotating mirror, and the rotating mirror 51 is rotated for driving transmission. The power transmitted via the shaft 81 rotates around the mirror rotation shaft 53.

The sensor optical axis S reflected by the reflecting surface 52 of the rotating mirror 51 moves in the sub-scanning direction on the mounting surface 11 as the reflected light rotates as the rotating mirror 51 rotates. In the image reading device 1, the position closest to the lower side in the vertical direction of the rotary mirror 51 in the moving direction of the sensor optical axis S that moves in the sub-scanning direction on the placement surface 11 in this way is the sensor optical axis S at the start of reading. It becomes the position. That is, the position closest to the arm 15 in the moving direction of the sensor optical axis S that is reflected by the rotating mirror 51 and moves in the sub-scanning direction on the mounting surface 11 is the position of the sensor optical axis S at the start of reading.

In this case, the illumination control unit 73 controls the illumination unit 60 to turn on the illumination unit 60, thereby irradiating the mounting surface 11 with linear light that spreads in the main scanning direction. Further, when drive control of the rotary motor 55 is performed by the motor control unit 72, the power generated by the rotary motor 55 is transmitted to the illumination unit 60 via the speed ratio conversion mechanism 80, whereby the illumination unit 60. Also rotates. That is, the power transmitted from the rotary motor 55 to the drive transmission rotating shaft 81 of the speed ratio conversion mechanism 80 is transmitted to the illumination unit 60 through the illumination first pulley 86, the belt 95 and the illumination second pulley 87. The illumination unit 60 rotates around the illumination rotation shaft 63 by this power transmitted via the drive transmission rotation shaft 81.

At that time, the speed ratio conversion mechanism 80 transmits power to the illumination unit 60 at a speed twice as high as the rotational speed when power is transmitted to the rotating mirror 51. On the other hand, when the rotating mirror 51 is rotated, the incident angle of the sensor optical axis S incident on the rotating mirror 51 from the second optical unit 40 and the sensor optical axis reflected by the rotating mirror 51 and directed toward the placement surface 11. Both the emission angle of S change together. For this reason, when the rotating mirror 51 rotates, the sensor optical axis S that is reflected by the rotating mirror 51 and travels toward the placement surface 11 rotates at an angle that is twice the angle that the rotating mirror 51 rotates. . Therefore, the illuminating unit 60 rotates the illuminating unit 60 at a rotational speed twice that of the rotating mirror 51 and rotates the rotating unit 51 at an angle twice the rotating angle of the rotating mirror 51, so that the illuminating unit 60 changes the illuminating optical axis L to the sensor optical axis. Rotate with S matched. As a result, the illumination unit 60 that is rotated by the power transmitted from the speed ratio conversion mechanism 80 emits light in a direction in which the illumination optical axis L coincides with the sensor optical axis S, and the sensor optical axis S is placed on the placement surface 11. Light is irradiated to the position that intersects with.

Since the irradiation light irradiated from the illumination unit 60 is a line-shaped light that spreads in the main scanning direction, the irradiation light irradiated onto the mounting surface 11 with the illumination optical axis L coincident with the sensor optical axis S is Irradiation is performed on the mounting surface 11 so as to overlap the sensor optical axis S extending in a line in the main scanning direction. That is, the illuminating unit 60 irradiates light onto a region that is read in a line shape in the main scanning direction on the placement surface 11 by the line sensor 31.

In this state, the control circuit 70 acquires an image read by the line sensor 31 by the image reading control unit 71, thereby acquiring line-shaped image information extending in the main scanning direction on the placement surface 11. That is, the medium P on the placement surface 11 irradiated with the light from the illumination unit 60 reflects this light, and a part of the reflected light enters the rotating mirror 51 along the sensor optical axis S. The rotating mirror 51 reflects this light along the sensor optical axis S toward the second optical unit 40, and the second optical unit 40 returns this light along the sensor optical axis S by the folding mirror 42. It is directed to the first optical unit 30. The first optical unit 30 transmits light traveling from the second optical unit 40 along the sensor optical axis S toward the first optical unit 30 through the condenser lens 35 and then received by the line sensor 31. The line sensor 31 converts the received light into an electrical signal, and transmits the converted electrical signal to the image reading control unit 71, whereby the image reading control unit 71 acquires the image information. As a result, the image reading control unit 71 acquires line-shaped image information extending in the main scanning direction on the placement surface 11.

The control circuit 70 controls the U-turn motor 45 and the rotary motor 55 by the motor control unit 72 while acquiring the line-shaped image information by the image reading control unit 71. As a result, the sensor optical axis S reflected by the rotating mirror 51 of the third optical unit 50 toward the mounting surface 11 is moved in the sub-scanning direction while the second optical unit 40 is moved in the direction approaching the first optical unit 30. , The rotating mirror 51 is rotated in the direction of moving away from the arm 15.

Further, when the rotating mirror 51 is rotated by the power generated by the rotating motor 55, the illumination unit 60 rotates at a rotational speed twice that of the rotating mirror 51. Thereby, the illumination optical axis L of the irradiation light emitted from the illumination unit 60 moves in the sub-scanning direction away from the arm 15 on the placement surface 11 together with the sensor optical axis S moving in the sub-scanning direction, and the illumination unit 60 irradiates the line-shaped light to the position where the sensor optical axis S is located. Thereby, the line sensor 31 reads the medium P on the placement surface 11 while scanning the placement surface 11 in the sub-scanning direction.

FIG. 12 is an explanatory diagram showing a state at the end of reading. The reading unit 20 moves the sensor optical axis S in the sub-scanning direction on the placement surface 11 as described above while reading with the line sensor 31, and the arm 15 is located in the movement range of the sensor optical axis S. The reading operation is finished when the end of the side is moved to the opposite end. That is, when the reading is finished, the control circuit 70 controls the U-turn motor 45 and the rotary motor 55 by the motor control unit 72 to move the second optical unit 40 to the position at the start of reading, and The rotating mirror 51 and the illumination unit 60 of the three optical units 50 are rotated to the rotation position at the start of reading.

That is, the second optical unit 40 is moved in the direction in which the second optical unit 40 is separated from the first optical unit 30 along the sensor optical axis S between the first optical unit 30 and the second optical unit 40. The rotating mirror 51 rotates the sensor optical axis S on the placement surface 11 in the sub-scanning direction in a direction approaching the arm 15, and the illumination unit 60 similarly illuminates the placement surface 11 in the sub-scanning direction. The optical axis L is rotated in the direction approaching the arm 15.

The image reading control unit 71 reads the image while moving the sensor optical axis S on the mounting surface 11 in the sub-scanning direction as described above, thereby converting the line-shaped image information extending in the main scanning direction into the sub-scanning direction. Are combined and read as a two-dimensional image in the main scanning direction and the sub-scanning direction. The image read as described above is subjected to image processing such as cropping by the image processing unit 74 so as to be an appropriate image as the image on the medium P, and stored in the storage unit 75. The image stored in the storage unit 75 is transmitted to the PC 100 via the communication unit 76 as necessary, and is stored in the PC 100 or performs arbitrary information processing.

The image reading apparatus 1 according to the above embodiment includes the speed ratio conversion mechanism 80 that sets the rotational speed ratio between the rotating mirror 51 that rotates by the rotational force from the rotating motor 55 and the illumination unit 60 to 1: 2. The illumination unit 60 can be rotated at a rotational speed twice that of the rotary mirror 51. Thereby, it is not necessary to control each using the power source which is different for the rotary mirror 51 and the illumination unit 60, and the rotation unit 51 always adjusts the rotation rate of the rotary mirror 51 with one rotary motor 55. It can be rotated at twice the rotation speed. Further, when viewed in the main scanning direction, the mirror rotation axis 53 coincides with the reflection surface 52 of the rotation mirror 51 and also coincides with the illumination rotation axis 63, so that the illumination unit 60 rotates the rotation mirror 51. Irrespective of the state, it is possible to irradiate light with the illumination optical axis L always aligned with the sensor optical axis S. As a result, the light irradiation direction can be easily changed in accordance with the reading position with a simple configuration.

In addition, since the irradiation light from the illumination unit 60 has a certain width in the sub-scanning direction, the illumination optical axis L is caused by the component tolerance of the illumination unit 60 and the like by matching the sensor optical axis S and the illumination optical axis L. Even if the deviation occurs, the sensor optical axis S can be accommodated in the irradiation light from the illumination unit 60. As a result, by aligning the sensor optical axis S and the illumination optical axis L, it is possible to easily align the reading position and the irradiation position of the irradiation light during manufacturing.

FIG. 13 is an explanatory diagram showing a state where the sensor optical axis and the illumination optical axis do not match. FIG. 14 is an explanatory diagram for reading a thick medium with the image reading apparatus shown in FIG. Further, the illumination optical axis L is not matched with the sensor optical axis S, but the sensor optical axis S and the illumination optical axis L are directed from the different directions toward the placement surface 11 so as to coincide on the placement surface 11. In this case, if the medium P to be read is a thin medium P, the illumination optical axis L can be positioned at the position of the sensor optical axis S on the medium P. However, when the medium P to be read is a thick medium P, the sensor optical axis S and the illumination optical axis L are respectively placed on the medium P at positions where the sensor optical axis S and the illumination optical axis L do not overlap. Cross. In this case, since the illumination optical axis L intersects the medium P at a position different from the position where the sensor optical axis S intersects the medium P, the illuminating unit 60 has a position read by the line sensor 31. Irradiates irradiation light to different positions. On the other hand, in the image reading apparatus 1 according to the present embodiment, since the illumination optical axis L is always coincident with the sensor optical axis S, the illuminating unit 60 applies to the medium P regardless of the thickness of the medium P to be read. The position where the sensor optical axes S intersect can be illuminated. As a result, a high-quality image can be obtained regardless of the thickness of the medium P.

Further, the mirror rotation axis 53 coincides with the position where the sensor optical axis S is reflected on the reflection surface 52 when viewed from the main scanning direction. Therefore, by rotating the rotation mirror 51, the mirror rotation axis 53 is rotated on the placement surface 11. The amount of movement when the sensor optical axis S is moved in the sub-scanning direction can be easily adjusted. As a result, reading control can be performed more easily.

In addition, the illumination unit 60 has the illumination rotation axis 63 disposed on the illumination optical axis L when viewed from the main scanning direction. Therefore, the illumination unit 60 is rotated to rotate the illumination optical axis on the placement surface 11. The amount of movement when moving L in the sub-scanning direction can be easily adjusted. As a result, the illumination optical axis L can be more easily matched with the sensor optical axis S.

[Modification]
In the image reading apparatus 1 according to the above-described embodiment, the mirror rotation shaft 53 coincides with the position where the sensor optical axis S is reflected on the reflection surface 52 of the mirror rotation shaft 53 when viewed from the main scanning direction. However, the mirror rotation axis 53 may be located on the reflection surface 52 other than the position where the sensor optical axis S is reflected. FIG. 15 is a modified example of the image reading apparatus according to the embodiment, and is an explanatory diagram when the mirror rotation axis is located above the reflection position of the sensor optical axis. FIG. 16 is a modified example of the image reading apparatus according to the embodiment, and is an explanatory diagram when the mirror rotation axis is located below the reflection position of the sensor optical axis. Even when the mirror rotation shaft 53 is located on the reflection surface 52 other than the position where the sensor optical axis S is reflected, the rotation mirror 51 is centered on the mirror rotation shaft 53 when the image reading device 1 reads an image. By rotating the rotary mirror 51, the sensor optical axis S can be moved on the placement surface 11 in the sub-scanning direction.

However, when the mirror rotation axis 53 is positioned on the reflection surface 52 other than the position where the sensor optical axis S is reflected, the position where the sensor optical axis S is reflected on the reflection surface 52 varies depending on the rotation angle of the rotation mirror 51. To do. For this reason, when the mirror rotation axis 53 is located at a position other than the position where the sensor optical axis S is reflected, the sensor optical axis S can be appropriately reflected regardless of the rotation angle of the rotation mirror 51. In addition, it is necessary to increase the size of the rotating mirror 51 to some extent. On the other hand, when the mirror rotation axis 53 is located at a position that reflects the sensor optical axis S, the sensor optical axis S reflects at the same position on the reflection surface 52 regardless of the rotation angle of the rotation mirror 51. . Therefore, in this case, the rotating mirror 51 can be reduced in size, and the reading unit 20 can be reduced in size. Therefore, the mirror rotating shaft 53 is located at a position where the sensor optical axis S is reflected. preferable.

Even when the mirror rotation axis 53 is positioned on the reflection surface 52 other than the position where the sensor optical axis S is reflected, the illumination rotation axis 63 of the illumination unit 60 is seen from the mirror rotation axis 53 when viewed in the main scanning direction. Is preferably matched. FIG. 17 is a modified example of the image reading apparatus according to the embodiment, and is an explanatory diagram when the mirror rotation axis is located at a position other than the reflection position of the sensor optical axis. FIG. 18 is a modified example of the image reading apparatus according to the embodiment, and is an explanatory diagram when the illumination rotation axis is located on a position other than the illumination optical axis. FIG. 19 is a modified example of the image reading apparatus according to the embodiment, and is an explanatory diagram showing a state where the mirror rotation axis is located at a position other than the reflection position of the sensor optical axis and coincides with the illumination rotation axis. Even when the mirror rotation axis 53 is located on the reflection surface 52 other than the position where the sensor optical axis S is reflected, the illumination rotation axis 63 of the illumination unit 60 coincides with the mirror rotation axis 53 when viewed in the main scanning direction. It is preferable to do so. In this case, the illumination rotation axis 63 of the illumination unit 60 is positioned not on the illumination optical axis L, but on the illumination light so that the illumination rotation axis 63 coincides with the mirror rotation axis 53 when viewed in the main scanning direction. It is arranged at a position displaced from the axis L. Thereby, when viewed in the main scanning direction, the mirror rotation axis 53 and the illumination rotation axis 63 can be made to coincide with each other, and the sensor rotation axis 53 and the illumination optical axis L can be made to coincide with each other. Further, by rotating the rotating mirror 51 and the illumination unit 60 around the illumination rotation axis 63, the sensor optical axis S and the illumination optical axis L can be kept matched regardless of the rotation angle.

The rotary mirror 51 and the illumination unit 60 have the mirror rotation axis 53 coincident with the illumination rotation axis 63 when viewed from the main scanning direction, and the mirror rotation axis 53 is the reflection surface 52 or the reflection surface of the rotation mirror 51. If it coincides with the extension line of 52, the sensor optical axis S and the illumination optical axis L can be kept coincident regardless of the rotation angle even if the sensor optical axis S is located at a position other than the reflection position. FIG. 20 is an explanatory diagram when the mirror rotation axis and the illumination rotation axis are located at the reflection position of the sensor optical axis on the reflection surface and the sensor optical axis and the illumination optical axis coincide with each other. FIG. 21 is an explanatory diagram when the mirror rotation axis and the illumination rotation axis are positioned above the reflection position of the sensor optical axis on the reflection surface and the sensor optical axis and the illumination optical axis coincide with each other. FIG. 22 is an explanatory diagram when the mirror rotation axis and the illumination rotation axis are positioned below the reflection position of the sensor optical axis on the reflection surface and the sensor optical axis and the illumination optical axis coincide with each other. FIG. 23 is an explanatory diagram in the case where the mirror rotation axis and the illumination rotation axis are located on the extension line of the reflecting surface and the sensor optical axis and the illumination optical axis coincide with each other. That is, if the mirror rotation axis 53 and the illumination rotation axis 63 coincide with each other and the mirror rotation axis 53 coincides with the reflection surface 52 or an extension line of the reflection surface 52, the mirror rotation axis 53 and the illumination rotation axis 63 correspond to the sensor. It is not only located at the reflection position of the optical axis S (FIG. 20), but also located above or below the reflection position of the sensor optical axis S (FIGS. 21 and 22), or on an extension line of the reflection surface 52. Even in the case (FIG. 23), the sensor optical axis S and the illumination optical axis L can be kept matched.

Next, when the mirror rotation axis 53 and the illumination rotation axis 63 coincide with each other and the mirror rotation axis 53 and the illumination rotation axis 63 are arranged on the reflection surface 52 or an extension line of the reflection surface 52 as described above, the rotation is performed. The fact that the sensor optical axis S and the illumination optical axis L coincide with each other regardless of the angle will be described. FIG. 24 is an explanatory diagram of each coordinate when the angle of the rotating mirror is 45 °. When the angle of the rotary mirror 51 is set to 45 ° and the sensor optical axis S and the illumination optical axis L are made to coincide with each other downward, the coordinates of the reflection position on the reflection surface 52 of the rotary mirror 51 are shown in FIG. It is assumed that (0, 0) as shown in FIG. Further, the coordinates of the mirror rotation axis 53 of the rotary mirror 51 are (a, b). At this time, the rotation angle of the rotating mirror 51 is θ, and the rotation angle of the illumination unit 60 is 2θ.

Further, when the rotating position of the rotating mirror 51 around the mirror rotating shaft 53 is rotated and the reflecting position when the reflecting surface 52 reflects the sensor optical axis S is (c, 0), c is expressed by the following equation (1). ).
c = a + b (tan (45 ° −θ)) (1)

Also, from the following equation (2), which is an additive theorem, and tan 45 ° = 1, the above equation (1) becomes the following equation (3).

Thereby, the sensor optical axis S passes through the coordinates of the following formula (4) and reflects at an angle of 2θ.

Next, the illumination optical axis L will be described. FIG. 25 is an explanatory diagram of each coordinate of the illumination optical axis. Assuming that the intersection coordinates of the illumination optical axis L with y = 0 are (d, 0), the equation of the illumination optical axis L when y = e · x + f when rotated by 2θ around (a, b) is The inclination e can be expressed by the following formula (5).

Here, in FIG. 25, (a, b), a perpendicular to the illumination optical axis L before rotation (l ₁ ), and a right angle connecting three points (0, f) passing through the illumination optical axis L after rotation. Triangles can be formed. Similarly, a right-angled triangle connecting three points (a, b), a perpendicular line (l ₁ ) to the illumination optical axis L after rotation, and (0, f) can be formed. The congruence condition of the right triangle is that the hypotenuse and the other one side are equal, but the two right triangles shown in FIG. 25 satisfy this condition, so the two right triangles are congruent. Therefore, the angle from (a, b) to (0, f) is θ. Therefore, the equation of the broken line portion V corresponding to the hypotenuse of the right triangle in FIG. 25 can be expressed as y = −tan θ · x + f, and since this straight line passes through (a, b), b = −a · tan θ + f, and f = a · tan θ + b. Therefore, by substituting f into the illumination optical axis L equation, it can be expressed by the following equation (6).

Since the above equation (6), which is an equation of the illumination optical axis L, passes through (d, 0), it can be expressed by the following equation (7).

Therefore, d = − (a · tan θ + b) × tan 2θ. Accordingly, the illumination optical axis L passes through (− (a · tan θ + b) × tan 2θ, 0) and is irradiated at an angle of 2θ.

Here, the condition for c = d is calculated. For this reason, the following formula (8) showing c = d is arranged.

If the above equation (8) is arranged, the following equation (9) is obtained.

Further rearranging the above equation (9) using the following equation (10), the following equation (11) is obtained, which can be further represented by the following equation (12).

a (1-tan ² (θ)) + b (1-tan (θ)) ² = −2a · tan ² (θ) −2b · tan (θ) (11)
a (tan ² (θ) +1) = − b (tan ² (θ) +1) (12)

Therefore, when the relationship of a = −b is established in the coordinates (a, b) of the mirror rotation axis 53, that is, when the mirror rotation axis 53 is on the reflection surface 52 when the rotation mirror 51 is 45 °, the sensor Both the optical axis S and the illumination optical axis L pass through the coordinates of the following equation (13) and overlap toward the mounting surface 11 at an angle of 2θ. As is clear from these, if the mirror rotation axis 53 and the illumination rotation axis 63 coincide with each other in the main scanning direction, and the mirror rotation axis 53 coincides with the reflection surface 52 or the extension line of the reflection surface 52, the rotation mirror 51. Regardless of the rotation angle between the illumination unit 60 and the illumination unit 60, the sensor optical axis S and the illumination optical axis L can be matched.

In the image reading apparatus 1 according to the above-described embodiment, the illumination unit 60 irradiates the placement surface 11 with light from the light emitting unit 61 in a line shape with the lens 62. You may make it irradiate toward the mounting surface 11 by changing the direction of the light from the light emission part 61. FIG. 26 is a modification of the image reading apparatus according to the embodiment, and is a detailed view of an illumination unit in which a mirror is used. For example, as illustrated in FIG. 26, the illumination unit 60 includes a reflection mirror 102 in addition to the light source unit 101, and the light source unit 101 and the reflection mirror 102 are formed integrally by being held by a holding member 103, These may be integrated so as to rotate around the illumination rotation shaft 63. In this case, the direction of the light emitted from the light source unit 101 is changed by being reflected by the reflection mirror 102, and the illumination optical axis L after the direction is changed becomes the direction that coincides with the sensor optical axis S. As described above, the illumination unit 60 may be configured to irradiate the placement surface 11 by changing the direction of the light from the light emitting unit 61, and rotates at twice the rotational speed of the rotary mirror 51. In addition, as long as the light from the light emitting unit 61 is finally irradiated in a direction that coincides with the sensor optical axis S, the configuration is not limited.

In the image reading apparatus 1 according to the above-described embodiment, the speed ratio conversion mechanism 80 transmits the power generated by the rotary motor 55 from the drive transmission rotary shaft 81 to the rotary mirror 51 and the illumination unit 60. The power generated by the rotary motor 55 may be transmitted to the other through one of them. FIG. 27 is a schematic diagram of the speed ratio conversion mechanism in the case where power is transmitted to the illumination unit via the rotating mirror, which is a modification of the image reading apparatus according to the embodiment. In the speed ratio conversion mechanism 80, for example, as shown in FIG. 27, the rotating mirror 51 is provided with rotating mirror direct coupling gears 110 that rotate integrally with the rotating mirror 51 at both ends in the main scanning direction. May be configured to transmit the power between the rotating mirror direct-coupled gear 110 and the illumination direct-coupled gear 115 by providing an illumination direct-coupled gear 115 that rotates integrally with the illumination unit 60. In this case, the power generated by the rotary motor 55 is transmitted from the drive transmission rotary shaft 81 to the rotary mirror 51 by the rotary pulley first pulley 91, the belt 95, and the rotary mirror second pulley 92. The rotating mirror 51 is rotated by the transmitted power.

Further, the transmission of power between the rotary mirror direct-coupled gear 110 and the illumination direct-coupled gear 115 is performed by rotating together with the first transmission gear 111 meshing with the rotary mirror direct-coupled gear 110 and the first transmission gear 111 and lighting. And the second transmission gear 112 meshed with the direct connection gear 115. These gears are paths that transmit power from the rotary mirror direct-coupled gear 110 to the illumination direct-coupled gear 115 via the first transmission gear 111 and the second transmission gear 112, and have a speed ratio that doubles the speed ratio. That is, the rotation speed ratio when power is transmitted to the rotating mirror 51 and the illumination unit 60 is 1: 2. As a result, power is transmitted to the illumination unit 60 at a rotational speed that is twice the rotational speed at which power is transmitted to the rotary mirror 51, and the illumination optical axis L of the irradiation light emitted from the illumination unit 60 is the rotational mirror. Regardless of the rotation angle between 51 and the illumination unit 60, it coincides with the sensor optical axis S reflected by the rotating mirror 51.

FIG. 28 is a modification of the image reading apparatus according to the embodiment, and is a schematic diagram of a speed ratio conversion mechanism when power is transmitted to a rotating mirror via an illumination unit. Alternatively, the speed ratio conversion mechanism 80 may be configured such that the power transmitted to the illumination unit 60 is transmitted to the rotating mirror 51, as shown in FIG. In this configuration, the rotating mirror direct-coupled gear 110, the first transmission gear 111, the second transmission gear 112, and the illumination direct-coupled gear 115 are one of the illumination units 60 disposed on both sides of the rotating mirror 51 in the main scanning direction. It is provided between the illumination unit 60 and the rotating mirror 51. The speed ratio conversion mechanism 80 configured as described above is configured so that the rotation motor 55 is connected to the illumination unit 60 by the first pulley 86 for illumination, the belt 95 and the second pulley 87 for illumination from the drive transmission rotating shaft 81. Is transmitted, and the illumination unit 60 is rotated by the transmitted power.

Of the power transmitted to the two illumination units 60, the power transmitted to the illumination unit 60 on the side where the illumination direct coupling gear 115 is provided is the illumination direct coupling gear 115, the second transmission gear 112, and the first transmission. It is transmitted to the rotating mirror 51 by the gear 111 and the rotating mirror direct connection gear 110, and the rotating mirror 51 is rotated by the transmitted power. These gears are paths that transmit power from the illumination direct coupling gear 115 to the rotary mirror direct coupling gear 110 via the second transmission gear 112 and the first transmission gear 111, and the speed ratio is halved. In other words, the rotational speed ratio when power is transmitted to the rotating mirror 51 and the illumination unit 60 is 1: 2. As a result, power is transmitted to the rotating mirror 51 at a rotational speed that is 1/2 the rotational speed at which power is transmitted to the illumination unit 60, and the rotational mirror 51 and the illumination unit 60 are mounted regardless of the rotational angle. The sensor optical axis S toward the placement surface 11 and the illumination optical axis L coincide.

In the image reading apparatus 1 according to the above-described embodiment, the speed ratio conversion mechanism 80 transmits the power generated by the rotary motor 55 from the drive transmission rotary shaft 81 to the rotary mirror 51 and the illumination unit 60. However, the power generated by the rotary motor 55 may be transmitted to the rotary mirror 51 and the illumination unit 60 through different paths. FIG. 29 is a modification of the image reading apparatus according to the embodiment, and is a schematic diagram of a speed ratio conversion mechanism when power is transmitted through different paths between the rotating mirror and the illumination unit. For example, as shown in FIG. 29, the speed ratio conversion mechanism 80 is provided with two worm gears of a first worm gear 121 and a second worm gear 122 on the motor output shaft 120, and the rotating mirror 51, the illumination unit 60, and the like from the two worm gears. However, power may be transmitted through separate paths.

In this case, a first worm wheel 126 is engaged with the first worm gear 121, and the first worm wheel 126 is connected to the first pulley 91 for rotating mirror so as to be rotatable integrally with the first worm wheel 126. Yes. A second pulley 92 for rotating mirror is attached to the rotating mirror 51, and a belt 95 is wound around the first pulley 91 for rotating mirror and the second pulley 92 for rotating mirror. On the other hand, the power extracted by the first worm gear 121 and the first worm wheel 126 is transmitted.

A second worm wheel 127 meshes with the second worm gear 122, and the second worm wheel 127 is connected to the first pulley 82 for drive transmission so as to be rotatable integrally with the second worm wheel 127. . The power thus extracted by the second worm gear 122 and the second worm wheel 127 is applied to the drive transmission rotating shaft 81 via the drive transmission first pulley 82, the belt 95, and the drive transmission second pulley 83. The drive transmission rotating shaft 81 is rotated by this transmitted power. Two first pulleys 86 for illumination are attached to the drive transmission rotating shaft 81 in correspondence with the two illumination units 60. The first pulley 86 for illumination and the illumination pulleys attached to the respective illumination units 60. When the belt 95 is wound around the second pulley 87, the illuminating unit 60 is transmitted with power from the drive transmission rotating shaft 81. As a result, the power extracted by the second worm gear 122 and the second worm wheel 127 is transmitted to the illumination unit 60.

As described above, the first worm gear 121 and the first worm wheel 126 that transmit power toward the rotating mirror 51, and the second worm gear 122 and the second worm wheel 127 that transmit power toward the illumination unit 60, The gear ratio is different. That is, the reduction ratio between the first worm gear 121 and the first worm wheel 126 is twice the reduction ratio between the second worm gear 122 and the second worm wheel 127. On the other hand, there is no speed change between the first pulley 91 for rotating mirror and the second pulley 92 for rotating mirror, and between the first pulley 86 for lighting and the second pulley 87 for lighting. The gear ratio is 1: 1. Thus, the rotation speed ratio when power is transmitted to the rotating mirror 51 and the illumination unit 60 is 1: 2. Accordingly, power is transmitted to the illumination unit 60 at a rotational speed that is twice the rotational speed at which power is transmitted to the rotary mirror 51, and the illumination optical axis L of the irradiation light emitted from the illumination unit 60 is determined by the rotary mirror 51. And the sensor optical axis S reflected by the rotary mirror 51, regardless of the rotation angle of the illumination unit 60.

Further, in the image reading apparatus 1 according to the above-described embodiment, the illumination units 60 are provided at two locations of the reading unit 20, but the illumination units 60 may be provided at two or more locations of the reading unit 20. For example, a plurality of illumination units 60 provided in the reading unit 20 may be provided on both sides in the main scanning direction with the rotating mirror 51 of the third optical unit 50 interposed therebetween. When viewed from the main scanning direction, the illumination unit 60 has the illumination rotation axis 63 coincident with the mirror rotation axis 53 and the illumination optical axis L coincides with the sensor optical axis S reflected by the reflection surface 52 of the rotation mirror 51. The number is not limited as long as it is configured to irradiate light in the direction in which the light is emitted.

In the image reading apparatus 1 according to the above-described embodiment, one reading unit 20 is provided, but a plurality of reading units 20 may be provided. FIG. 30 is a modified example of the image reading apparatus according to the embodiment, and is an explanatory diagram when a plurality of reading units are provided. For example, as shown in FIG. 30, two reading units 20 may be provided in one image reading apparatus 1. In this case, the two reading units 20 are arranged by being connected to one arm 15. In this way, by providing a plurality of reading units 20, a large medium P can be read by one reading unit 20, and when the medium P is a book, different pages can be read by each reading unit 20. Can do.

DESCRIPTION OF SYMBOLS 1 Image reader 10 Mounting stand 11 Mounting surface 15 Arm 20 Reading unit 30 1st optical unit 31 Line sensor 35 Condensing lens 40 2nd optical unit 42 Folding mirror 45 U-turn motor 50 3rd optical unit 51 Rotating mirror 52 Reflection Surface 53 Mirror rotation shaft 55 Rotation motor (rotary actuator)
DESCRIPTION OF SYMBOLS 60 Illumination part 63 Illumination rotating shaft 70 Control circuit 71 Image reading control part 72 Motor control part 73 Illumination control part 74 Image processing part 80 Speed ratio conversion mechanism 81 Rotating shaft for drive transmission

Claims

A line sensor that reads the medium placed on the placement surface in a line in the main scanning direction of the placement surface;
A rotating mirror that reflects and rotates the sensor optical axis of the line sensor to move the sensor optical axis in a sub-scanning direction perpendicular to the main scanning direction on the mounting surface with respect to the mounting surface; ,
Illuminating at least the reading area of the line sensor and rotating in conjunction with movement of the reading area in the sub-scanning direction; and
A rotary actuator that rotates the rotary mirror and the illumination unit around a rotation axis parallel to the main scanning direction;
A speed ratio converting mechanism that sets a rotational speed ratio of the rotating mirror that rotates by the rotational force from the rotary actuator and the illumination unit to 1: 2.
With
The mirror rotation axis of the rotating mirror coincides with the reflecting surface of the rotating mirror or an extension line of the reflecting surface when viewed from the main scanning direction, and coincides with the illumination rotating axis of the illumination unit,
The illumination unit emits light in a direction that matches an illumination optical axis of light emitted from the illumination unit with respect to the sensor optical axis reflected by the reflecting surface of the rotating mirror when viewed in the main scanning direction. Irradiating an image reading apparatus.
2. The image reading apparatus according to claim 1, wherein the mirror rotation axis coincides with a position where the sensor optical axis is reflected on the reflection surface when viewed from the main scanning direction.
3. The image reading apparatus according to claim 2, wherein the illumination unit has the illumination rotation axis disposed on the illumination optical axis when viewed from the main scanning direction.