JP4539459B2 - Image reading device - Google Patents

Description

  The present invention relates to the structure of an image reading apparatus employed in, for example, a multi-function device (MFD).

  In general, an image reading apparatus for reading a document as image data is mounted on a copying machine or a multifunction machine. This image reading apparatus includes an image sensor such as a charge coupled device (CCD) or a contact image sensor (CIS), and an image is read by such an image sensor scanning a document.

  FIG. 9 is a perspective view of a main part of a conventional image reading apparatus. The image reading apparatus 1 includes a contact image sensor 2. Although not shown in the figure, the image reading apparatus 1 includes a body frame formed in a box shape, and the contact image sensor 2 is disposed inside the body frame so that the upper surface 3 faces upward. Has been. Further, a contact glass plate is provided on the upper surface of the main body frame, and this contact glass plate constitutes a mounting table on which a document is placed. The contact image sensor 2 is arranged immediately below the contact glass plate and reads an image from a document placed on the contact glass plate while being moved in the direction of the arrow 4. At this time, if the contact image sensor 2 is inclined in the longitudinal direction or in the direction of the arrow 4, the contact image sensor 2 is inclined with respect to the contact glass plate on which the document is placed. As a result, the image cannot be accurately read from the document. Therefore, conventionally, roller units 5 and 6 for supporting smooth sliding are arranged at both ends of the contact image sensor 2 (see, for example, Patent Documents 1 to 3).

  FIG. 10 is an exploded perspective view of a main part of a conventional image reading apparatus, in which the roller units 5 and 6 are separated from the contact image sensor 2. The roller unit 5 includes a frame 7 and rollers 8 and 9 disposed at both ends of the frame 7. The frame 7 includes two engagement pins 10. However, in FIG. 10, only one engagement pin 10 is shown because of the angle relationship in the figure. The contact image sensor 2 has two engagement holes 11 at its end. The roller unit 5 is attached to one end of the contact image sensor 2 by fitting the two engagement pins 10 into the two engagement holes 11. The roller unit 6 has the same configuration as the roller unit 5 and includes a frame 12, rollers 8 and 9, and two engagement pins. However, in FIG. 10, the engagement pin is not illustrated because of the angle of the drawing. The roller unit 6 is attached to the other end of the contact image sensor 2 by fitting the two engagement pins into two engagement holes 13 provided at the end of the contact image sensor 2.

JP 2004-266314 A JP-A-11-98322 JP-A-9-261424

  By the way, in recent years, miniaturization of copying machines and multi-function machines has been promoted. In particular, in a multifunction machine or the like equipped with a flat bed type image reading device, various improvements have been made since the dimension in the direction of arrow 4 in FIG. 9 is reduced. For example, FIG. 11 is an exploded perspective view of a main part of another conventional image reading apparatus, and illustrates an improvement for miniaturization. That is, in this image reading apparatus, roller units 15 and 16 are attached to the contact image sensor 14. The roller unit 15 includes a pair of rollers 17 and 18, and the rollers 17 and 18 are shifted by a distance f in the longitudinal direction of the contact image sensor 14. The roller unit 16 also includes a pair of rollers 17 and 18, which are similarly displaced by a distance f in the longitudinal direction of the contact image sensor 14. As described above, the pair of rollers 17 and 18 provided in the roller units 15 and 16 are relatively shifted by the distance f, whereby a direction perpendicular to the longitudinal direction of the contact image sensor 14 (indicated by an arrow 4 in the figure). Direction) between the rollers 17 and 18 is shortened. Therefore, the external dimensions of the image reading apparatus are also reduced in the same direction, and consequently the overall external dimensions of the multifunction machine are reduced.

  However, since the rollers 17 and 18 are in contact with the contact glass plate and roll in the direction of the arrow 4 as described above, if the rollers 17 and 18 are shifted from each other by the distance f, the roller unit 15 , 16 and the contact glass plate, rattling between the roller units 15 and 16 and the contact image sensor 14 and between the contact image sensor 14 and the contact glass plate are likely to occur. Therefore, the contact image sensor 14 is inclined in the longitudinal direction or is easily inclined in the direction of the arrow 4, and as a result, the contact image sensor 14 may not be able to accurately read an image from the document.

  Therefore, an object of the present invention is to provide a compact image reading apparatus including a contact image sensor that can accurately read an image from a document.

(1) In order to achieve the above object, an image reading apparatus according to the present invention includes a main body frame having an opening on an upper surface, and a contact glass attached so that a surface constituting a document placement surface is exposed to the opening. A plate, a housing facing the back surface of the contact glass plate, a light source attached to the housing and arranged to face the back surface of the contact glass plate, and a plurality of juxtaposed in the longitudinal direction of the housing A contact image sensor provided in the body frame in a state of being movable in the lateral direction of the casing, and provided at an end portion in the longitudinal direction of the casing. a roller unit holding portion having a mounting surface extending in the longitudinal direction outward perpendicular to the vertical plane and the vertical plane extending downward from the top surface, accommodated in the roller unit holder, the contactor A pair of rollers that are in contact with the rear surface of the glass plate and can roll in the short direction of the housing include a roller unit arranged in parallel in the short direction of the housing. The roller unit includes a pair of support shafts that rotatably support the rollers, and a frame that supports the support shafts, and the frames are positioned and held on the vertical surface and the mounting surface, and The dimension of the roller unit holding portion in the short direction is set to be equal to or smaller than the dimension of the casing in the short direction.

  According to this configuration, the contact image sensor scans the document by moving in the short direction. A roller unit is provided at the end of the contact image sensor in the longitudinal direction, and the pair of rollers provided in the roller unit are arranged side by side in the lateral direction and are in contact with the back surface of the contact glass plate. . Therefore, when the contact image sensor moves, the end portion thereof is supported by the roller, and the contact image sensor is prevented from being inclined with respect to the back surface of the contact glass plate. The roller unit is housed in a roller unit holding portion provided at an end of the housing of the contact image sensor, and the short-side dimension of the roller unit holding portion is the same as that of the housing. Since the width dimension is set to be equal to or smaller than the short dimension, the roller unit does not protrude outward in the short direction from the casing. Therefore, in the design of the contact image sensor, the dimension in the short direction can be kept small.

The roller unit is not placed on the upper surface of the housing, but is placed on the placement surface so as to be dropped downward from the upper surface. Therefore, the roller unit is arranged on the housing such that the top of the roller protrudes slightly upward from the upper surface of the housing, so that the contact image sensor is positioned in a state of being very close to the contact glass plate. Is done. In addition, the placement surface described above enables accurate positioning of the roller unit in the vertical direction, and the vertical surface allows accurate positioning of the roller unit in the longitudinal direction. In addition, since the roller is supported by the frame, the mounting accuracy of the roller is improved. That is, the roller is accurately positioned without being displaced with respect to the housing of the contact image sensor .

(2) The roller unit holding part may be constituted by a groove having a pair of vertical surfaces that sandwich the frame in the longitudinal direction of the casing. In this case, more accurate positioning of the roller unit in the vertical direction and the longitudinal direction is realized.

( 3 ) It is preferable that the pair of rollers is disposed on a virtual straight line along the short direction. By arranging the pair of rollers on a virtual straight line along the short direction, when the contact image sensor moves, the roller unit is inclined relative to the contact image sensor, and the roller unit is contact glass. It is reliably prevented that the contact image sensor is inclined relative to the plate and the contact image sensor is inclined relative to the back surface of the contact glass plate.

(4) the support shaft is what is supported at both ends to the frame is preferred. Thereby, the mounting accuracy of the roller is further improved.

  According to the present invention, since the roller unit is housed in the housing of the contact image sensor and does not protrude from the housing in the short direction of the housing, the contact image sensor is designed to be compact, and as a result, the image The reading device can be downsized. In addition, since the roller unit includes a pair of rollers arranged in the short direction, the contact image sensor is prevented from tilting when moving in the short direction. Therefore, the distance between the contact image sensor and the contact glass plate is kept constant, and as a result, good image reading is realized.

  Hereinafter, the present invention will be described in detail based on preferred embodiments with appropriate reference to the drawings.

  FIG. 1 is an external perspective view of an image reading apparatus 30 according to an embodiment of the present invention.

  The image reading device 30 can be used, for example, as a scanner unit of a multi-function device (MFD) having a printer function and a scanner function integrally, and as an image reading unit of a copying machine. However, in the present invention, the printer function is an arbitrary mechanism. For example, the image reading device 30 may be configured as a flatbed scanner (FBS) having only a scanner function.

  As shown in the figure, the image reading apparatus 30 includes a reading table 31 that functions as an FBS, and a document pressing cover 33 is attached to the reading table 31 so as to be freely opened and closed. The document pressing cover 33 includes an auto document feeder (ADF) 32. The reading table 31 includes a substantially rectangular parallelepiped main body frame 34, a contact glass plate 35 provided on the top surface (upper surface) of the main body frame 34, and an image reading unit 36 built in the main body frame 34. The document is placed on the contact glass plate 35. When the document pressing cover 33 is closed, the document is fixed by the document pressing cover 33. The image reading unit 36 moves below the contact glass plate 35 along the contact glass plate 35, thereby reading an image from the original.

  An operation panel 37 is provided on the front side of the reading table 31. The operation panel 37 includes various operation buttons and a liquid crystal display unit. The image reading device 30 operates according to an instruction from the operation panel 37. When the image reading device 30 is configured as an MFD, a computer can be connected to the image reading device 30. In that case, the image reading apparatus 30 can operate not only by an instruction from the operation panel 37 but also by an instruction transmitted from the computer via a scanner driver or the like.

  As described above, the document pressing cover 33 includes the ADF 32 that continuously conveys documents from the document tray to the discharge tray. In the conveyance process by the ADF 32, the document passes through the platen 38, and the image reading unit 36 reads an image from the document below the platen 38. However, in the present embodiment, this ADF 32 may be omitted.

  FIG. 2 is a plan view of the reading table 31 and shows the internal structure of the reading table 31. FIG. 3 is a cross-sectional view of the reading mounting table 31.

As shown in FIGS. 1 and 3, the main body frame 34 of the reading table 31 includes a container-like lower frame 39 whose upper surface is open, and an upper cover 42 having an opening 41 on the upper surface 40. The main body frame 34 is configured by fitting the upper cover 42 onto the frame 39. The contact glass plate 35 is attached to the upper cover 42 so as to be exposed to the opening 41 .

  As shown in FIG. 2, the image reading unit 36 is disposed in the lower frame 39. Both the lower frame 39 and the upper cover 42 are made of synthetic resin. The lower frame 42 includes a base portion 43 constituting a bottom plate, a side wall 44 rising from the periphery of the base portion 43, and a partition plate 45, which are integrally formed. The partition plate 45 partitions a portion where the image reading unit 36 is disposed and a portion where the substrate of the operation panel 37 is disposed. The lower frame 39 includes support ribs for supporting the contact glass plate 35, bosses for screwing various members, through holes for electrical wiring, and the like. However, since these are appropriately designed according to the embodiment of the reading table 31, detailed description thereof is omitted.

  As shown in FIG. 2, the image reading unit 36 includes a CIS unit 50 (contact image sensor), a carriage 51, a guide shaft 52, and a belt driving mechanism 53. The image reading unit 36 includes a roller unit 58 not shown in the figure. The CIS unit 50 is a so-called contact type image sensor. The CIS unit 50 irradiates the original with light and receives reflected light from the original, and converts the received light into an electrical signal. As will be described in detail later, the CIS unit 50 includes an elongated rectangular parallelepiped casing 70, and the casing 70 is fitted into the carriage 51. The carriage 51 moves below the contact glass plate 35 (see FIG. 1).

  Specifically, the carriage 51 is fitted to a guide shaft 52 that extends over the width direction of the lower frame 39. The carriage 51 is driven by the belt drive mechanism 53 and slides on the guide shaft 52. The carriage 51 urges the carriage 51 to be in close contact with the contact glass plate 35 while holding the CIS unit 50. The means for urging the carriage 51 is known and will be described later. That is, the CIS unit 50 held by the carriage 51 is moved along the contact glass plate 35 in the short direction of the housing 70. Here, the “short direction” is a direction perpendicular to the longitudinal direction of the housing 70 and along the lower surface of the contact glass plate 35.

  As shown in FIG. 3, the carriage 51 is mounted with the CIS unit 50 so as to be carried on the upper side thereof. A shaft receiving portion 54 is formed on the lower surface of the carriage 51 so as to be fitted over the guide shaft 52 from above. The shaft receiving portion 54 and the guide shaft 52 are fitted to each other, and the carriage 51 is slidable in the axial direction of the guide shaft 52 while being supported by the guide shaft 52. Further, a belt gripping portion 55 projects downward from the side of the shaft receiving portion 54. The belt gripping portion 55 grips a timing belt 61 of a belt driving mechanism 53 described later. As a result, the timing belt 61 and the carriage 51 are connected. Then, the driving force is transmitted from the belt driving mechanism 53 to the carriage 51, so that the carriage 51 moves on the guide shaft 52.

  Also, spring receivers 56 are formed at two locations on the left and right sides of the carriage 51 on which the CIS unit 50 is mounted. The spring receiver 56 holds the coil spring 57 while positioning it. That is, the coil spring 57 is interposed between the CIS unit 50 and the carriage 51. The coil spring 57 urges the carriage 51 toward the contact glass plate 35, and the CIS unit 50 mounted on the carriage 51 is pressed against the lower surface of the contact glass plate 35.

  The roller unit 58 is provided on both ends of the CIS unit 50. The roller unit 58 will be described in detail later. As described above, the CIS unit 50 moves along the contact glass plate 35 as the carriage 51 moves while being pressed against the lower surface of the contact glass plate 35. The roller unit 58 supports the smooth movement of the CIS unit 50.

  FIG. 4 is a plan view of the reading mounting table 31 and shows a schematic configuration of the belt driving mechanism 53.

  As shown in FIG. 4, the belt drive mechanism 53 includes a drive pulley 59, a driven pulley 60, a timing belt 61 wound around these, and a motor (not shown). The timing belt 61 is an endless belt having teeth formed inside. The timing belt 61 is configured to make a circumferential motion when the motor rotates the driving pulley 59.

  As shown in the figure, the drive pulley 59 is disposed at the left rear of the lower frame 39. The timing belt 61 wound around the drive pulley 59 extends to the front side of the lower frame 39 and is wound around an intermediate pulley 62 disposed in front of the guide shaft 52. Further, the timing belt 61 is bent at a substantially right angle, extends along the guide shaft 52 to the right end of the lower frame 39, and is wound around a driven pulley 60 disposed near the right end of the lower frame 39. That is, the timing belt 61 is constructed in a substantially L shape as shown in FIG. The portion between the driven pulley 60 and the intermediate pulley 62 of the timing belt 61 wound in this way, that is, the portion along the guide shaft 52 is gripped by the belt gripping portion 55 of the carriage 51, thereby The timing belt 61 and the carriage 51 are connected. Of course, as the timing belt 61, in addition to the endless belt, an endless belt in which both end portions of the belt are fixed to the carriage 51 may be employed.

  FIG. 5 is an enlarged exploded perspective view of the CIS unit 50.

  The CIS unit 50 includes the casing 70 and a light source and a light receiving element provided in the casing 70.

  The housing 70 is made of, for example, a synthetic resin, and is formed in an elongated rectangular parallelepiped shape as shown in FIG. The housing 70 contains the light source and the light receiving element. The upper surface 74 of the housing 70 faces the rear surface 75 of the contact glass plate 35 as shown in FIG. Therefore, the light source and the light receiving element are also in close proximity to the back surface 75 of the contact glass plate 35.

  The light source typically includes an LED (Light Emitting Diode) and a light guide 73. This LED is not shown in the figure, but is disposed in the inner part of the housing 70. The light guide 73 is typically made of a transparent synthetic resin and extends in the entire longitudinal direction of the housing 70. The light guide 73 is exposed on the upper surface 74 of the housing 70, and light emitted from the LEDs is guided to the entire longitudinal direction of the housing 70 by the light guide 73. As a result, the light emitted from the LEDs is distributed substantially evenly over the entire length of the housing 70 and is irradiated onto the document.

  In the present embodiment, the housing 70 is provided with a plurality of light receiving elements. Each light receiving element is arranged in the longitudinal direction of the casing 70 at the inner bottom of the casing 70. Each light receiving element includes a condenser lens 72. These condenser lenses 72 are exposed on the upper surface 74 of the housing 70. The light irradiated and reflected on the original is condensed by each condenser lens 72 and received by each corresponding light receiving element. These light receiving elements are photoelectric conversion elements, and output electrical signals based on the received light. This electric signal is an image signal of the image shown on the document.

  Roller unit holding portions 76 and 77 are provided at both ends in the longitudinal direction of the housing 70. The roller unit holding portion 76 is composed of a step portion formed at a corner portion in the longitudinal direction of the housing 70. Specifically, this step portion is formed by a vertical surface 78 and a mounting surface 79 continuous therewith. The vertical surface 78 is a surface extending downward from the upper surface 74 of the housing 70. The mounting surface 79 is a surface extending perpendicularly to the lower end of the vertical surface 78 and extending outward in the longitudinal direction.

  The roller unit 58 is disposed along the vertical surface 78 and placed on the placement surface 79. The mounting surface 79 has a positioning hole 80 for positioning and fixing the roller unit 58. The roller unit 58 is positioned and fixed to the roller unit holding portion 76 when an engagement pin 81 described later is fitted into the positioning hole 80. In addition, the dimension W1 in the short direction of the roller unit holding part 76 is set to a predetermined dimension. The dimension W1 is variously changed according to the specifications of the CIS unit 50, but is set to be equal to or smaller than the dimension W2 in the short side direction of the housing 70. In addition, since the roller unit holding | maintenance part 77 is the structure similar to the roller unit holding | maintenance part 76, the description is abbreviate | omitted.

  FIG. 6 is a perspective view of the roller unit 58.

  The roller unit 58 includes a frame 82 and a pair of rollers 83 and 84. The frame 82 is configured as a block that supports the rollers 83 and 84. The frame 82 includes a pair of side plates 85 and 86 opposed to each other in the longitudinal direction and a pair of connecting plates 87 for connecting them, and these can be integrally formed of, for example, a synthetic resin. By providing the pair of side plates 85 and 86, roller accommodating portions 90 and 91 are formed between the side plates 85 and 86. The rollers 83 and 84 are accommodated in the roller accommodating portions 90 and 91, respectively. Although not shown in the drawing, the frame 82 includes a bottom plate, and the engagement pin 81 projects from the lower surface of the bottom plate. The side plates 85 and 86 are provided with bearing portions 88 and 89, respectively. The bearing portions 88 and 89 are formed by notched concave portions provided in the side plates 85 and 86, and rotatably support support shafts 92 and 93 provided on the rollers 83 and 84, respectively.

  The roller 83 has a disk shape and includes the support shaft 92. The support shaft 92 is provided at the center of the roller 83 and extends in the longitudinal direction. Both end portions of the support shaft 92 are fitted and supported by the bearing portions 88 of the side plates 85 and 86, so that the roller 83 is disposed in a rotatable state in the roller accommodating portion 90. Since the roller 84 has the same configuration as the roller 83, the description thereof is omitted. Further, the roller 83 and the roller 84 are arranged on an imaginary straight line 94. The virtual straight line 94 is a straight line that is virtually set along the short direction. That is, the pair of rollers 83 and 84 are arranged on a straight line and are not displaced in the longitudinal direction. Of course, the pair of rollers 83 and 84 may be displaced in the longitudinal direction.

  FIG. 7 is an enlarged perspective view of the CIS unit 50.

  With the pair of rollers 83 and 84 supported by the frame 82 (see FIG. 6), the engaging pin 81 of the frame 82 is fitted into the positioning hole 80 as described above. As a result, the roller unit 58 is positioned and fixed to the housing 70 as shown in FIG. In this state, as shown in FIG. 3, the rollers 83 and 84 of the roller unit 58 abut against the back surface 75 of the contact glass plate 35. The rollers 83 and 84 roll around the back surface 75 of the contact glass plate 35 by rotating around the support shafts 92 and 93.

  In the image reading apparatus 30 according to the present embodiment, as shown in FIG. 1, the surface 95 of the contact glass plate 35 constitutes a document placement surface on which a document is placed. The document is placed face down on the surface 95 of the contact glass plate 35. As shown in FIGS. 1 and 3, the original is scanned by moving the CIS unit 50 of the image reading unit 36 in the short direction.

  A roller unit 58 is provided at the longitudinal end of the CIS unit 50 (see FIG. 7), and the rollers 83 and 84 provided in the roller unit 58 are in contact with each other in a state of being arranged in parallel in the short direction. It is in contact with the back surface 75 of the glass plate 35. Therefore, the CIS unit 50 moves in a state where the end portions thereof are supported by the rollers 83 and 84, and therefore the CIS unit 50 moves smoothly without being inclined with respect to the back surface 75 of the contact glass plate 35. The roller unit 58 is housed in roller unit holders 76 and 77 provided in the casing 70 of the CIS unit 50, and as shown in FIGS. 5 and 7, the roller unit holder 76. 77, the dimension W1 in the short direction is set to be equal to or smaller than the dimension W2 in the short direction of the housing 70. Therefore, the roller unit 58 does not protrude outward from the casing 70 in the lateral direction, and as a result, the dimension in the lateral direction can be kept small in the design of the CIS unit 50.

  Thus, since the CIS unit 50 is designed to be compact in the short direction, the image reading device 30 can be downsized. Further, since the roller unit 58 includes the rollers 83 and 84, the CIS unit 50 is prevented from being tilted when moving, and the distance between the CIS unit 50 and the contact glass plate 35 is kept constant. As a result, good image reading is realized.

  In particular, in the present embodiment, the pair of rollers 83 and 84 are disposed on the virtual straight line 94. That is, the rollers 83 and 84 are arranged in parallel in the short direction. Therefore, there is an advantage that when the CIS unit 50 moves, the pair of rollers 83 and 84 is reliably prevented from being inclined relative to the CIS unit 50. Further, the pair of rollers 83 and 84 is reliably prevented from being inclined relative to the back surface 75 of the contact glass plate 35 and the CIS unit 50 is inclined relative to the back surface 75 of the contact glass plate 35. There is an advantage that.

  Further, in the present embodiment, the roller unit 58 is housed in roller unit holding portions 76 and 77 constituted by the above stepped portions (see FIG. 5). The roller unit 58 is not placed on the upper surface 74 of the housing 70 as in the prior art, but is placed on the placement surface 79 constituting the stepped portion so as to be dropped downward from the upper surface 74. Placed. Therefore, the roller unit 58 is disposed on the casing 70 such that the tops of the rollers 83 and 84 protrude slightly upward from the upper surface 74 of the casing 70. As a result, the CIS unit 50 is positioned in a state of being very close to the back surface 75 of the contact glass plate 35. As a result, the CIS unit 50 can accurately read an image from the original. In addition, since the CIS unit 50 is mounted on the mounting surface 79, the roller unit 58 can be positioned more accurately in the vertical direction. Further, since the CIS unit 50 is placed along the vertical surface 78 constituting the step portion, there is an advantage that the roller unit 58 can be accurately positioned in the longitudinal direction.

  In the present embodiment, as shown in FIG. 6, the rollers 83 and 84 are supported by the frame 82 via the support shafts 92 and 93, so that the mounting accuracy of the rollers 83 and 84 with respect to the housing 70 is improved. Will improve. That is, the rollers 83 and 84 are accurately positioned with respect to the casing 70 without being displaced. In addition, since the support shafts 92 and 93 are supported at both ends by the frame 82, the mounting accuracy of the casing 70 for the rollers 83 and 84 is further improved. As a result, when the CIS unit 50 moves, it is more reliably prevented from tilting with respect to the back surface 75 of the contact glass plate 35, and more accurate image reading is realized.

  FIG. 8 is a perspective view of a CIS unit 100 according to a modification of the present embodiment.

  The CIS unit 100 according to this modification differs from the CIS unit 50 according to the above embodiment in that in the CIS unit 50, roller unit holding portions 76 and 77 having stepped portions are formed at the longitudinal ends of the housing 70. On the other hand, in the present modification, a groove 101 is provided in the housing 70, and the roller unit 58 is fitted in the groove 101. That is, this groove 101 constitutes a roller unit holding part. Other configurations are the same as those of the CIS unit 50 described above.

  Also in this modified example, the roller unit 58 is provided at the end of the CIS unit 100 in the longitudinal direction, and the rollers 83 and 84 provided in the roller unit 58 are arranged in parallel in the short direction. It contacts the back surface 75 of the contact glass plate 35. Therefore, the CIS unit 100 moves in a state where the end portions thereof are supported by the rollers 83 and 84. Therefore, the CIS unit 100 is moved relative to the back surface 75 of the contact glass plate 35 or the roller unit 58. It does not tilt. Further, the CIS unit 100 can move smoothly without the roller unit 58 being inclined with respect to the back surface 75 of the contact glass plate 35. Further, the roller unit 58 is housed in a groove 101 (roller unit holding portion) provided in the housing 70 of the CIS unit 100, and the dimension W1 of the groove 101 in the short direction is the housing 70. Is set to a dimension W2 or less in the short direction. Therefore, the roller unit 58 does not protrude outward from the casing 70 in the lateral direction, and as a result, the dimension in the lateral direction can be kept small in the design of the CIS unit 100.

  Since the CIS unit 100 according to the present modification is also designed to be compact in the lateral direction as with the CIS unit 50 according to the above-described embodiment, the image reading device 30 can be downsized. Further, since the roller unit 58 includes the rollers 83 and 84, the CIS unit 100 is prevented from being tilted when moving, and the distance between the CIS unit 100 and the contact glass plate 35 is kept constant. . As a result, good image reading is realized.

  In this modified example, since the pair of rollers 83 and 84 are arranged on the virtual straight line 94, the rollers 83 and 84 are juxtaposed in the short direction. Therefore, the CIS unit 100 is There is an advantage that it is reliably prevented from being tilted with respect to the back surface 75 of the contact glass plate 35 when moving.

  Further, in this modification, the roller unit 58 is fitted into the groove 101, so that the roller unit 58 is attached to the casing 70 so that the tops of the rollers 83 and 84 protrude slightly upward from the upper surface 74 of the casing 70. Be placed. Thereby, the CIS unit 100 is positioned in a state of being very close to the back surface 75 of the contact glass plate 35. As a result, the CIS unit 100 can accurately read an image from the original. In particular, since the roller unit 58 is fitted into the groove 101, more accurate positioning in the vertical direction and the longitudinal direction is possible.

  The present invention can be applied to an image reading apparatus employed in a copying machine, a multifunction machine, or the like.

FIG. 1 is an external perspective view of an image reading apparatus according to an embodiment of the present invention. FIG. 2 is a plan view of the reading stage of the image reading apparatus according to the embodiment of the present invention. FIG. 3 is a cross-sectional view of the reading stage of the image reading apparatus according to the embodiment of the present invention. FIG. 4 is a plan view of the reading stage of the image reading apparatus according to the embodiment of the present invention, and shows the structure of the belt driving mechanism. FIG. 5 is an enlarged exploded perspective view of the CIS unit of the image reading apparatus according to the embodiment of the present invention. FIG. 6 is a perspective view of the roller unit of the image reading apparatus according to the embodiment of the present invention. FIG. 7 is an enlarged perspective view of the CIS unit of the image reading apparatus according to the embodiment of the present invention. FIG. 8 is an enlarged perspective view of a CIS unit according to a modification of the embodiment of the present invention. FIG. 9 is a perspective view of a main part of a conventional image reading apparatus. FIG. 10 is an exploded perspective view of a main part of a conventional image reading apparatus. FIG. 11 is an exploded perspective view of a main part of another conventional image reading apparatus.

DESCRIPTION OF SYMBOLS 30 ... Image reading device 31 ... Reading mounting stand 34 ... Main body frame 35 ... Contact glass plate 36 ... Image reading unit 39 ... Lower frame 40 ... Upper surface 41 ... Opening 42 ... upper cover 50 ... CIS unit 51 ... carriage 52 ... guide shaft 53 ... belt drive mechanism 54 ... shaft receiver 56 ... spring receiver 58 ... roller unit DESCRIPTION OF SYMBOLS 70 ... Housing 72 ... Light receiving element 73 ... Light guide 74 ... Upper surface of housing 75 ... Back surface of contact glass plate 76 ... Roller unit holding part 77 ... Roller unit holding Portion 78 ... Vertical surface 79 ... Mounting surface 80 ... Positioning hole 81 ... Engagement pin 82 ... Frame 83 ... Roller 84 ... Roller 85 ... Side plate 86 ... Side plate 88 ... Bearing part 89 ... Bearing part 92 ... Support shaft 93 ... Support shaft 94 ... Virtual straight line 95 ... Surface of contact glass plate 100 ... CIS unit 101 ... groove

Claims (4)

A body frame having an opening on the upper surface;
A contact glass plate attached so that the surface constituting the document placement surface is exposed to the opening;
A housing facing the back surface of the contact glass plate, a light source attached to the housing and arranged to face the back surface of the contact glass plate, and a plurality of light receiving elements arranged in parallel in the longitudinal direction of the housing A contact image sensor provided in the main body frame so as to be movable in a short direction of the casing;
A roller unit holding portion provided at an end portion in the longitudinal direction of the housing, and having a vertical surface extending downward from the upper surface of the housing and a mounting surface extending orthogonally to the vertical surface and extending outward in the longitudinal direction ;
A roller unit that is housed in the roller unit holding portion and that is in contact with the back surface of the contact glass plate and that can roll in the short direction of the housing; Have
The roller unit includes a pair of support shafts that rotatably support the rollers and a frame that supports the support shafts, the frames are positioned and held on the vertical surface and the mounting surface, and the rollers The image reading apparatus in which the dimension in the short direction of the unit holding unit is set to be equal to or smaller than the dimension in the short direction of the casing. The image reading apparatus according to claim 1, wherein the roller unit holding portion includes a groove having a pair of vertical surfaces that sandwich the frame in a longitudinal direction of the casing. The image reading apparatus according to claim 1 , wherein the pair of rollers are arranged on a virtual straight line along the short direction. The image reading apparatus according to claim 1 , wherein the support shaft is supported at both ends by the frame .

Images