JP2014012594A - Sheet conveyance device and image reading apparatus, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet conveyance device capable of conveying sheets, which differ in thickness, in a compact and simple configuration and an image reading apparatus, and an image forming apparatus.SOLUTION: A sheet conveyance device has a conveyance path 114 for conveying sheets formed therein by a main unit 102 and a counter unit 109 opposing the main unit 102. In the sheet conveyance device and an image reading apparatus and an image forming apparatus, spacing of the conveyance path 114 can be changed by changing a relative position between the counter unit 109 and the main unit 102, and can be changed in a simple and compact configuration.

Description

  The present invention relates to a sheet conveying apparatus, an image reading apparatus, and an image forming apparatus that convey sheets.

  Generally, devices such as scanners, fax machines, copiers, and printers are equipped with, for example, an image reading unit that reads an image formed on a sheet and a sheet conveying device that conveys a sheet to an image forming unit that forms an image on a sheet. Has been.

  Such a sheet conveying apparatus is required to have a high sheet conveying performance that can convey various sheets such as a thin sheet and a thick sheet. In particular, scanners that are also used in window work, etc., are required to be able to transport not only thin paper such as OA (Office Automation) paper, checks, and tracing paper, but also thick sheets such as plastic cards. It is done.

  Therefore, conventionally, a scanner has been devised in which a driven roller and an image reading unit provided on one side of a sheet conveying path are attached to a frame via a spring so that sheets having different thicknesses can be conveyed stably. (See Patent Document 1). As described above, when the spring is interposed between the frame and the frame, the roller and the reading unit can be moved according to the thickness of the sheet, and sheets having different thicknesses can be stably conveyed.

JP 2011-254251 A

  However, if the movable part is configured by contracting a spring between the frame as in the scanner described in Patent Document 1, many parts such as a spring are required, and the structure becomes complicated. . In addition, since each member is independently movable, the number of parts is larger and the structure is complicated.

  Further, it is necessary to secure a space for contracting the spring and a space for moving the driven roller and the image reading unit in the frame, which increases the size of the apparatus. Further, if the movable range is expanded in order to convey a thicker sheet, there is a problem that the above-described apparatus is further increased in size.

  SUMMARY An advantage of some aspects of the invention is that it provides a sheet conveying apparatus, an image reading apparatus, and an image forming apparatus that are capable of conveying sheets having different thicknesses with a small and simple configuration.

  The sheet conveying apparatus according to the present invention is a conveying path that conveys a sheet, a main body that forms one surface of the conveying path, and a counter that is disposed to face the main body and forms the other surface of the conveying path. A conveyance path interval changing unit is provided that changes a relative position between the unit and the main body portion and the opposing unit to change a distance between the one surface and the other surface of the conveyance path.

  According to the present invention, the sheet conveying apparatus can change the interval between the conveying paths by changing the relative position between the main body and the opposing unit by the conveying path interval adjusting means. For this reason, the space | interval of a conveyance path can be changed with the simple structure which changes the relative position of a main-body part and an opposing unit, Therefore, a number of parts can also be decreased. Further, the entire sheet conveying apparatus can be made compact.

1 is an external view showing a document scanner according to a first embodiment of the present invention. FIG. 2 is a schematic diagram showing a configuration of the document scanner of FIG. 1. FIGS. 2A and 2B are schematic diagrams illustrating a conveyance path of the document scanner in FIG. 1, in which FIG. 1A shows a state where the conveyance path is narrow, and FIG. It is a schematic diagram which shows the conveyance path space | interval change part which concerns on the 1st Embodiment of this invention, Comprising: (a) is a case where a conveyance path is narrowed, (b) is a case where a conveyance path is widened. It is a schematic diagram which shows operation | movement of the knob of the conveyance path change part of FIG. 4, Comprising: (a) is a case where a conveyance path is narrowed, (b) is a case where a conveyance path is widened. It is a figure which shows the positional relationship of the driven roller and conveyance roller which concern on the 1st Embodiment of this invention, Comprising: (a) is a case where a conveyance path is narrow, (b) is a case where a conveyance path is wide. It is a schematic diagram which shows the conveyance path space | interval change part which concerns on the 2nd Embodiment of this invention, Comprising: When (a) narrows a conveyance path and (b) widens a conveyance path. It is a schematic diagram which shows the document scanner which concerns on the 3rd Embodiment of this invention, Comprising: (a) is a state with a narrow conveyance path, (b) is a state with a wide conveyance path.

  Hereinafter, a sheet conveying apparatus according to an embodiment of the present invention and an image reading apparatus equipped with the sheet conveying apparatus will be described with reference to the drawings. In the following description, the sheet is not limited to a paper document such as a thick paper and a thin paper, but includes an OHP sheet, a plastic card (credit card or driver's license), and the like. A direction orthogonal to the sheet conveying direction is referred to as a width direction, and a direction perpendicular to the sheet conveying direction is referred to as a vertical direction.

<First Embodiment>
<Schematic configuration of document scanner>
As shown in FIGS. 1 and 2, a document scanner 100 as an image reading apparatus is a small document scanner, and is used by being placed on a desk or being carried outside. As shown in FIG. 2, the document scanner 100 includes a sheet conveying device 130 and an image reading unit 140, and an image reading unit (image reading unit) 140 converts an image of the sheet F conveyed by the sheet conveying device 130. And output to an external device or built-in memory.

  The sheet conveying device 130 includes a main body frame 102 that constitutes the main body of the sheet conveying device 130 and the document scanner 100, and a counter unit 109 that is disposed to face the main body frame (main body) 102. . The main body frame 102 and the opposing unit 109 form a conveyance path 114 for conveying the sheet F and constitute the outer shape of the document scanner 100.

  More specifically, the upper surface 108 of the main body frame 102 forms one side of the conveyance path of the sheet F, and conveyance rollers 103 and 104 that convey the sheet F are provided. The conveyance rollers 103 and 104 are provided so as to sandwich the image reading unit 140 on the upstream side and the downstream side in the sheet conveyance direction of the image reading unit 140, respectively. Is transported. Further, the sheet F from which the image has been read is discharged by the downstream conveying roller 104.

  The opposing unit 109 has a lower surface 110 that constitutes the other side of the conveyance path 114 of the sheet F conveyed by the conveyance rollers 103 and 104, and is driven so as to face the conveyance rollers 103 and 104. Rollers 111a and 111b are provided. These driven rollers 111a and 111b are pressing portions that contact and press the sheet F from the opposing unit side, and the sheet F is stably conveyed by the conveying rollers 103 and 104 while being pressed by the driven rollers 111a and 111b. Is done. Note that the opposing unit 109 of the present embodiment is formed of a plate-like member (for example, an aluminum alloy plate) that does not have a drive system, and the main body frame 102 is provided with a drive system such as a transport roller 103. . Thereby, it is possible to realize a very thin and compact conveying structure as a whole. When an aluminum alloy plate is used as the plate-like member, not only rigidity can be ensured but also weight reduction can be realized. Since the opposing unit 109 made of such a plate-like member does not have a drive system, it may be provided detachably with respect to the main body frame 102. Accordingly, maintenance of the image reading unit 140 (for example, cleaning of the contact glass surface) can be easily performed, and an abnormal document can be quickly removed when a jam or the like is poorly conveyed.

  The image reading unit 140 includes an image reading sensor 106 provided on the main body frame (main body unit) 102 between the conveyance rollers 103 and 104, and reads an image of a sheet conveyed by the sheet conveyance device 130. It has become a means. In this embodiment, the image reading sensor 106 that reads an image on the sheet F uses a contact image sensor (CIS). As the image reading sensor 106, any other sensor system such as a CCD (Charged Coupled Devices) sensor may be used.

  In addition, the image reading sensor 106 is provided with a rod lens array 107 that forms an image of the sheet F on the photoelectric conversion element array of the image reading sensor 106. The white reference plate 115 is arranged. More specifically, the white reference plate 115 is provided at a position facing the rod lens array 107, which is an image reading position, and when the sheet F is not present, the density is read by the image reading sensor 106, and the image is read. This is a reference plate for calibrating (setting) the reading conditions. That is, the light amount correction, shading correction, and white reference correction of the image reading sensor 106 are performed using the density of the white reference plate 115 as a reference. The white reference plate 115 may be composed of only a white plate, but in this embodiment, the reference plate protection glass 116 is attached to the upper surface of the white reference plate 115 to improve the antifouling performance.

  Since the document scanner 100 is configured as described above, as illustrated in FIG. 2, when the sheet F is inserted into the entrance of the conveyance path 114, the sheet F is detected by the entrance sensor 113 provided in the main body frame 102. To do. When the user presses a print start button (see FIG. 1), the control unit (not shown) starts driving the transport roller 103 and sets the image reading unit 140 to an image reading standby state.

  When the conveyance roller 103 starts to rotate, the sheet F is conveyed to the image reading unit 140 while being sandwiched between the conveyance roller 103 and the driven roller 111a, passes over the rod lens array 107, and is imaged by the image reading sensor 106. Is read. The read image data is stored in an external device or an internal / external storage unit, and the sheet F on which the image has been read is transported in conjunction with the transport roller 103 and the image reading unit 140. It is discharged by 104.

  The reading of the image may be started in accordance with an instruction from an external device, or the reading operation may be started simultaneously with the entrance sensor 113 detecting the sheet. The inlet sensor 113 may be any sensor such as a reflection type optical sensor, a transmission type optical sensor, a lever type contact sensor, or the like.

<Roller configuration>
Next, the configuration of the conveying rollers 103 and 104 and the driven rollers 111a and 111b as conveying sections that convey the sheet F will be described with reference to FIG. Regarding the shape of the rollers, there is no difference between the transport rollers 103 and 104 and the driven rollers 111a and 111b on the upstream and downstream sides in the transport direction. Therefore, when not distinguished in the following description, the conveyance roller 103 and the driven roller 111a on the conveyance upstream side will be described as an example, and the description of the conveyance roller 104 and the driven roller 111b on the conveyance downstream side will be omitted.

  As shown in FIG. 3A, the conveyance roller 103 is a comb-like roller, and a cylindrical roller portion 151 with respect to a roller shaft 150 extending in the width direction orthogonal to the conveyance direction of the sheet F. Are provided with a predetermined interval.

  More specifically, the roller shaft 150 is rotatably supported by the main body frame 102, and the transport roller 103 is configured by fixing four roller units 155 to the roller shaft 150. In the roller unit 155, three roller portions 151 are connected via a connecting shaft portion 154. Therefore, the transport roller 103 has an uneven shape in the axial direction. Moreover, the roller part 151 which forms these uneven | corrugated shaped convex parts is comprised with high friction members, such as rubber | gum. That is, a comb-like conveyance roller 103 is provided on the conveyance path side of the main body frame 102 (main body portion). In other words, the comb-like conveyance roller 103 is fixed to one surface of the conveyance path 114. In this embodiment, the unevenness of the conveying roller 103 is set to about 8 to 15 mm, but it may be longer than this. Further, the interval between the concaves and convexes is not necessarily constant.

  On the other hand, a plurality of driven rollers 111 a are also arranged in a line in the axial direction, like the roller portion 151 of the transport roller 103. As shown in FIG. 2, the driven roller 111 a is disposed so that at least a part of the driven roller 111 a overlaps with the conveyance roller 103 in the sheet conveyance direction D <b> 1, and forms a conveyance nip together with the conveyance roller 103. That is, the transport roller 103 is a pressing portion provided on the transport path side of the opposing unit 109 where the lower surface 110 of the transport path 114 forms the other surface. The upstream driven roller 111a is located upstream of the rotation center of the conveying roller 103 facing the upstream side in the sheet conveying direction, and the downstream driven roller 111b is rotated by the conveying roller 104 opposed to the rotation center thereof. The center is also downstream. Further, the driven rollers 111a and 111b are configured not to come into direct contact with the transport roller 103 even though the transport rollers 103 and 104 form a transport nip.

<Configuration of conveyance path interval changing unit>
Next, the configuration of a conveyance path interval changing unit (conveyance path interval changing unit) 160 that is a mechanism for changing the interval of the conveyance path 114 of the sheet F will be described with reference to FIGS. 3A is a diagram illustrating the conveyance path 114 of the sheet F in a state where the interval is narrowed, and FIG. 3B is a diagram illustrating the conveyance path 114 of the sheet F in a state where the interval is widened.

  As shown in FIG. 3A and FIG. 4A, the opposing unit 109 described above has a first end 109a in the width direction fitted to the main body frame 102, and the opposite first unit 109a. The two end portions 109b are fitted in the knob 117 constituting the operation portion 161. The opposing unit 109 is fitted and held by the fitting between the main body frame 102 and the knob 117 so that it does not come off the main body frame 102 when receiving a reaction force from the sheet F during document conveyance. .

  Further, the first and second end portions 109a and 109b of the opposing unit 109 have contact surfaces 163 and 165 with the main body frame 102 formed as inclined surfaces. Furthermore, the contact surfaces 164 and 166 of the main body frame 102 that are in contact with the contact surfaces 163 and 165 are also formed as inclined surfaces corresponding to the inclination of the contact surfaces 163 and 165 of the opposing unit 109 (see FIG. 4). Therefore, the opposing unit 109 is movable along the inclination of the contact surfaces 164 and 166 of the main body frame 102, and the contact surfaces 163 to 166 are moved up and down while sliding the opposing unit 109 by the contact surfaces 163 to 166. The interval 114 can be changed.

  That is, the contact surfaces 163 to 166 serve as a direction changing unit 162 that converts the moving force in the sliding direction D2 with respect to the main body frame 102 (main body portion) of the opposing unit 109 into a direction D3 different from the sliding direction.

  More specifically, the contact surfaces 163 to 166 are inclined toward the axial direction of the transport roller 103 and are configured to be able to slide the opposing unit 109 in the axial direction of the transport roller 103. Further, the contact surfaces 163 to 166 are inclined at an angle such that the amount of movement of the facing unit 109 in the sliding direction is greater than the amount of elevation (the amount of movement in the vertical direction). In other words, the inclination angles of the contact surfaces 163 to 166 are set such that the ratio of the amount of elevation relative to the amount of movement in the sliding direction is less than 1.

  On the other hand, the knob 117 into which the second end 109b of the opposing unit 109 is fitted is an operation unit 161 for sliding the opposing unit 109 to change the interval of the transport path 114, and the direction described above. A conveyance path interval changing unit 160 is configured together with the conversion unit 162. Specifically, as shown in FIG. 5, the knob 117 has an elliptical shape, is rotatable with respect to the opposing unit 109, and forms an elliptical cam with the side surface of the main body frame 102. . Therefore, when the knob 117 is rotated from the position shown in FIG. 5A to the position shown in FIG. 5B, the knob 117 moves outward in the width direction, and FIG. 3A and FIG. 4A. From this position, the position becomes the position of FIG. 3B and FIG. 4B. When the knob 117 moves in the width direction, the opposing unit 109 fitted to the knob 117 is also slid in the width direction.

  As shown in FIG. 6A, when the opposing unit 109 is located at the narrowest position where the conveyance path 114 is the narrowest, the driven roller 111 a of the opposing unit 109 is a roller portion 151 in the axial direction of the conveyance roller 103. It is in the position which overlaps with the recessed part 156 in between. At this time, the driven roller 111a is positioned so as to overlap the roller portion 151 in the vertical direction perpendicular to the sheet conveying direction. That is, when the interval of the conveyance path 114 is changed narrowly by the conveyance path interval changing unit 160, the driven roller (pressing portion) 111a faces the concave portion of the comb-like conveyance roller 103 or the vicinity thereof. Further, in the state where the conveyance path interval is the narrowest (the conveyance path interval is d1), the driven roller 111a of the facing unit 109 is positioned at the axial center of the recess 156 of the conveyance roller 103.

  On the other hand, FIG. 6B is a diagram illustrating a case where the facing unit 109 is at the widest position where the interval d2 of the transport path 114 is the widest (d2> d1). In the widest position where the interval of the conveyance path 114 is widened, the driven roller 111 a of the facing unit 109 is in a position overlapping the roller portion 151 between the roller portions 151 in the axial direction of the conveyance roller 103. That is, when the interval of the conveyance path 114 is widely changed by the conveyance path interval changing unit 160, the driven roller (pressing unit) 111 a faces the roller portion 151 of the comb-like roller 103 or the vicinity thereof. At this time, the driven roller 111a does not overlap the roller portion 151 in the vertical direction perpendicular to the sheet conveying direction. The variable amount of the conveyance path interval is set to be 1 to 2 mm in the present embodiment, but is almost equal to the difference between the maximum value and the minimum value of the thickness of the sheet F that can be conveyed. You can do it.

  Next, the operation of the conveyance path interval changing unit 160 will be described. As described above, the conveyance path interval changing unit 160 changes the relative position between the main body frame (main body part) 102 and the opposing unit 109 to be the upper surface 108 and the other surface of the main body frame 102 which is one side of the conveyance path. The distance from the lower surface 110 of the opposing unit 109 is changed. More specifically, the conveyance path interval changing unit 160 moves the counter unit 109 along the axial direction of the conveyance roller 103 to change the conveyance path interval. Therefore, since the sheet conveying apparatus 130 is configured to be able to change the interval of the conveying path 114, when the sheet F is a thin sheet F 1, the user adjusts the knob 117 to move the opposing unit 109 to the position shown in FIG. ) To the narrowest position. When the facing unit 109 is at the narrowest position, the positions of the conveying roller 103 and the driven roller are offset in the vertical direction. Therefore, the sheet F1 is elastically deformed by the driven roller 111a, so that the conveying roller 103 and driven roller are It enters between the rollers 111a. The sheet F1 is pressed toward the conveying roller 103 with a force that the driven roller 111a attempts to return. A frictional force is generated between the sheet F1 and the conveying roller 103 by the pressing force, and the sheet F1 is not slipped by the conveying roller 103. Be transported.

  When the sheet F is a thick sheet F2 such as a plastic card, the user rotates the knob 117. At this time, when the opposing unit 109 slides from the narrowest position in the axial direction of the conveying roller 103 by the rotation of the knob 117, as shown in FIGS. 3 (b) and 4 (b), the opposing unit 109 goes up the contact surfaces 164 and 166 of the main body frame 102. That is, the moving force in the axial direction D2 of the conveying roller 103 from the knob 117 is converted by the contact surfaces 163 to 165 into a conveying path interval changing direction D3 different from the axial direction. While maintaining the parallel state, the interval of the conveyance path 114 is widened.

  When the interval of the conveyance path 114 is widened, the user inserts the thick sheet F2 into the entrance of the conveyance path 114 and conveys the sheet by the conveyance roller 103. In this case, since the interval of the conveyance path 114 is wide, even if the sheet to be conveyed is a thick sheet F2, the sheet is conveyed by the conveyance roller 103 and the driven roller 111a without applying an unnecessarily large clamping pressure. can do. Further, at this time, the driven roller 111a and the conveying roller 103 are at positions facing each other in the axial direction, and therefore, there is little escape of the force that presses the sheet F2. Therefore, for example, even if a sheet slightly thicker than the distance between the conveyance roller 103 and the driven roller 111a is slightly deformed during conveyance, a sufficient conveyance force can be expected.

  Furthermore, even if the tip of the driven roller 111a is at a position opposite the roller portion 151 of the transport roller 103, a sufficient distance d3 can be secured between them, so that the two come into contact even if the opposing unit 109 is slightly deformed. Can be prevented.

  As described above, the document scanner 100 (sheet conveyance device 130) according to the present embodiment can change the interval of the conveyance path 114 by moving the counter unit 109 up and down by the conveyance path interval changing unit 160 while sliding it. . For this reason, the interval of the conveyance path 114 can be changed according to the thickness of the sheet F with a simple configuration in which the opposing unit 109 is simply slid.

  Further, in addition to a simple configuration in which the opposing unit 109 is moved (slid) while maintaining a parallel relationship with the axis of the comb-like conveying roller 103, the entire opposing unit slides in accordance with the interval of the conveying path 114. Combined with raising and lowering, the entire apparatus can be made compact.

  In particular, when the conveyance roller 103 is configured by a comb-like roller and the opposing unit 109 is slid in the axial direction to narrow the interval between the conveyance paths 114, the driven roller 111a enters the recess 156 of the conveyance roller 103. It is For this reason, the entire apparatus can be stored compactly by setting the opposing unit 109 to the narrowest position.

  Furthermore, since the driven roller 111a is located in the axial center of the concave portion 156 of the transport roller 103 at the narrowest position, the driven roller 111a does not move the transport roller 103 even if the transport path interval slightly changes. Contact with the roller portion 151 can be prevented. For this reason, it is possible to sufficiently maintain the conveyance performance of a thin document even if the accuracy of the components is slightly reduced.

  In addition, since the conveyance path interval changing unit 160 is configured to move the opposing unit 109 so that the ratio of the lifting amount to the moving amount in the sliding direction is less than 1, the moving amount in the sliding direction is increased. I can. For this reason, the inclination angle of the contact surfaces 163 to 166 can be relaxed, and the opposing unit 109 can be smoothly moved with respect to the main body frame 102.

  In the above description, the opposing unit 109 is fitted to the main body frame 102 and is also fitted to the knob 117. For example, the first end 109a of the opposing unit 109 and the main body frame 102 You may make it arrange | position an elastic member between these. In this case, the knob 117 does not need to be fitted to the opposing unit 109, and the interval of the conveyance path 114 can be changed only by changing the position of pressing the opposing unit 109 pressed by an elastic member such as a spring. . The opposing unit 109 may be held with respect to the main body frame 102 by using an elastic member, magnetic force, a guide member, or the like. For example, when magnetic force is used, a magnet is provided near the contact surfaces 164 and 166 of the main body frame, and the opposing unit contact surfaces 163 and 165 are made of a magnetic member. Thereby, the opposing unit 109 can be held on the main body frame 102 by the magnetic force between them.

  In this embodiment, the interval of the conveyance path 114 is operated by rotating the elliptical knob 117. However, the interval of the conveyance path may be changed by sliding the opposing unit 109 by another operation. . For example, it is also preferable to directly operate the opposing unit 109 by providing a protrusion on the surface of the opposing unit.

<Second Embodiment>
Next, a sheet conveying apparatus according to the second embodiment of the present invention will be described. The sheet conveying apparatus according to the second embodiment is different from the sheet conveying apparatus according to the first embodiment in that a conveyance path interval changing unit is configured using a parallel link mechanism. Since this is the same, description thereof is omitted.

  As shown in FIG. 7, in the sheet conveying apparatus 130A, the direction changing unit 162A of the conveying path interval changing unit 160A is configured by a parallel link mechanism 180. The parallel link mechanism 180 is configured by link arms 181 and 182 connected to the first and second ends of the opposing unit 109, respectively, and connects the opposing unit 109 and the main body frame 102 so as to be relatively movable. Yes.

  Specifically, the link arms 181 and 182 are configured to be rotatable in the axial direction of the transport roller with the connecting portion of the main body frame 102 as a fulcrum, and when the knob 117 is operated and pulled in the axial direction. Rotate and move up and down while sliding the opposing unit 109. In addition, the link arms 181 and 182 are set such that the length and the attachment position thereof have a slide amount larger than the lift amount.

  As described above, the parallel link including the link arms 181 and 182 can also change the interval of the conveyance path 114 while sliding the opposing unit 109 while maintaining the parallelism between the opposing unit 109 and the main body frame 102. .

<Third Embodiment>
Next, a document scanner according to the third embodiment of the invention will be described. The document scanner according to the third embodiment is different from the document scanner according to the first embodiment in the sliding direction of the counter unit and the configuration of the image reading apparatus. Accordingly, in the following description, only the above differences will be described, and description of other configurations will be omitted.

  As shown in FIG. 8, in the document scanner 100A, the conveyance path interval adjustment unit 160 of the sheet conveyance device 130B inclines the contact surface of the direction changing unit along the sheet conveyance direction, and the opposing unit 109 slides in the sheet conveyance direction. It is comprised so that it may be raised / lowered.

  Therefore, the position of the opposing unit 109 in the sheet conveyance direction differs according to the interval of the conveyance path 114. Specifically, as shown in FIG. 8A, when the opposing unit 109 is at the narrowest position, the upstream driven roller 111 a has a rotation center that is a distance d4 from the rotation center of the transport roller 103. It is offset upstream in the sheet conveying direction. Further, the downstream driven roller 111 b has its rotation center offset from the rotation center of the conveyance roller 103 by a distance d5 to the downstream side in the sheet conveyance direction.

  On the other hand, as shown in FIG. 8B, when the opposing unit 109 is at the widest position, the upstream driven roller 111a has a rotation center at a distance d6 from the rotation center of the conveyance roller 103 in the sheet conveyance direction. It is offset upstream. Further, the downstream driven roller 111 b has its rotational center offset from the rotational center of the conveying roller 103 by a distance d7 to the downstream side in the sheet conveying direction.

  Here, the offset amount of the upstream driven roller 111a is set such that the distance d4 is larger than the distance d6 and decreases as the distance between the conveyance paths 114 increases (d4> d6). For this reason, the conveyance of a thin sheet can be stabilized in a state where the conveyance path interval is narrow, and the conveyance of a thick sheet is easily stabilized in a state where the conveyance path interval is wide.

  On the other hand, the offset amount of the downstream driven roller 111b is set so that the distance d7 is larger than the distance d5, and the offset amount increases as the conveyance path interval increases (d7> d5). For this reason, it is possible to mitigate the impact when the leading edge of a hard and thick document comes into contact with the conveying roller 104.

  Further, the image reading device 140A of the document scanner 100A has an illumination device 121 that illuminates the conveyed sheet F, and the light reflected by the sheet F via the rod lens array 107 is converted into the photoelectric of the sensor substrate 120. The conversion element is configured to receive light.

  Further, a white reference plate 115A, which is provided at a position facing the image reading position of the image reading sensor 106 of the opposing unit 109 and is read by the image reading sensor 106 when calibrating image reading conditions, is a sheet. A density difference is provided in the transport direction.

  That is, when the facing unit 109 slides in the sheet conveyance direction, the relative position between the white reference plate 115A and the rod lens array 107 changes, and the density of the portion of the white reference plate 115A facing the image reading position changes. It has become. Specifically, when the conveyance path interval is narrow, the dark side of the white reference plate 115A faces the optical axis center of the rod lens array 107, and when the conveyance path interval is wide, the thin side of the white reference plate 115A is the rod lens array. It faces the center of the optical axis. As described above, the conveyance path interval is changed, and the density of the white reference plate 115A is changed in accordance with the change, so that the light amount of the illumination unit can be accurately adjusted even if the conveyance path interval is changed.

  In the above-described embodiment, the opposing unit 109 is configured to be movable in the sheet conveying direction or the axial direction of the conveying roller 103. However, if the direction is orthogonal to the vertical direction, the opposing unit 109 can be moved in any direction. You may make it slide. Further, the conveyance path interval changing unit (conveyance path interval changing means) 160 may change the interval of the conveyance path 114 by moving the main body frame 102 along the axial direction of the conveyance roller 103. That is, the conveyance path interval changing unit 160 may change the interval of the conveyance path 114 by moving at least one of the main body frame (main body unit) 102 and the opposing unit 109 along the axial direction of the conveyance roller 103. In this case, as described above, it is desirable that the change amount of the interval of the conveyance path 114 is small with respect to the movement amount of at least one of the main body frame 102 and the opposing unit 109. Further, the driven roller 111 a as the pressing portion does not necessarily exist, and the conveyance roller 103 may form a nip with the lower surface 110 of the facing unit 109.

  The interval between the two conveying surfaces constituting the conveying path 114 is intentionally created to be wide or narrow in order to correspond to the type of sheet (document) to be conveyed. However, the conditions of the sheet to be conveyed are limited. If so, they may be configured at regular intervals. In general, the image reading apparatus is configured such that the conveyance path interval is narrowed around the image reading sensor, and conversely, the document is widened in the vicinity of the document feeding unit and in the vicinity of the sheet discharging unit so that the document can be easily inserted.

  Further, as the reference plate, a black reference plate may be used instead of the white reference plate. When a black reference plate is used as the reference plate, the density is read with the illumination turned off. In addition, the inventions described in the above-described embodiments may be combined in any way, and the above-described sheet conveying device is conveyed by the sheet conveying device 130 as well as the document scanner. The image forming apparatus can be mounted on a fax machine, a copier, a printer, and an image forming apparatus of a composite machine of these having image forming means for forming an image on a sheet.

102: Main body (main body frame), 103, 104: Conveying roller, 106: Image reading sensor, 109: Opposing unit, 111a, 111b: Pressing part (driven roller), 115, 115A: Reference plate (white reference plate), 130: Sheet conveying device, 151: Roller unit, 156: Concave portion, 160, 160A: Conveyance path interval changing means (conveying path interval changing unit), 162, 162A: Direction changing unit

Claims (14)

A conveyance path for conveying a sheet;
A main body forming one surface of the transport path;
An opposing unit disposed opposite the main body and forming the other surface of the transport path;
A sheet conveying apparatus comprising: a conveyance path interval changing unit configured to change a distance between the one surface and the other surface of the conveyance path by changing a relative position between the main body and the opposing unit. A comb-like conveyance roller is provided on the conveyance path side of the main body,
A pressing portion is provided on the conveyance path side of the opposing unit corresponding to the concave portion of the comb-shaped conveyance roller,
The sheet conveying apparatus according to claim 1, wherein the conveying path interval changing unit changes the interval of the conveying path by moving the counter unit along an axial direction of the conveying roller. When the interval of the conveyance path is changed narrowly by the conveyance path interval changing unit, the pressing portion faces the concave portion of the comb-like conveyance roller or the vicinity thereof,
The said pressing part faces the roller part of the said comb-tooth-shaped roller, or its vicinity when the space | interval of the said conveyance path is changed widely by the said conveyance path space | interval change means, Sheet conveying device. A conveyance roller is provided on the conveyance path side of the main body,
2. The transport path interval changing unit changes the transport path interval by moving at least one of the main body and the opposing unit along an axial direction of the transport roller. The sheet conveying apparatus according to the description.   5. The sheet conveying apparatus according to claim 4, wherein a change amount of the interval of the conveyance path is small with respect to a movement amount of at least one of the main body and the opposing unit by the conveyance path interval changing unit. . A conveyance roller is provided on the conveyance path side of the main body,
The sheet conveying apparatus according to claim 1, wherein the conveying path interval changing unit changes the interval of the conveying path by moving the counter unit along an axial direction of the conveying roller.   The sheet conveying apparatus according to claim 1, wherein the conveying path interval changing unit changes the interval of the conveying path by moving the counter unit along a sheet conveying direction. A conveyance path for conveying a sheet;
A comb-like conveyance roller fixed to one side of the conveyance path;
An opposing unit forming the other surface of the transport path;
A sheet conveying apparatus comprising: a conveying path interval changing unit configured to change the interval of the conveying path by moving the opposing unit while maintaining a parallel relationship with the shaft of the comb-shaped conveying roller. A transport roller for transporting the sheet;
A main body that forms one side of a conveyance path of a sheet conveyed by the conveyance roller;
An opposing unit that is disposed to face the main body and forms the other side of the transport path;
A conveyance path having a direction conversion unit that converts a movement force in a sliding direction relative to the main body of the counter unit to a direction different from the slide direction, and changing the interval between the conveyance paths by moving the counter unit up and down while sliding. A sheet conveying apparatus comprising: an interval changing unit; The conveying roller is a comb-like roller in which a plurality of cylindrical roller portions are provided at a predetermined interval with respect to a roller shaft extending in a width direction perpendicular to the sheet conveying direction,
The opposing unit has a pressing part that contacts and presses the sheet from the opposing unit side,
The transport path interval changing means slides the opposing unit in the axial direction of the transport roller, and at the narrowest position of the opposing unit where the transport path interval is the narrowest, The sheet conveying apparatus according to claim 9, wherein the sheet conveying apparatus overlaps the concave portion between the roller portions in the axial direction and overlaps the roller portion in a vertical direction perpendicular to the sheet conveying direction.   3. The sheet conveying apparatus according to claim 1, wherein the conveying path interval changing unit moves the counter unit so that a ratio of an ascending / descending amount to an amount of movement in the sliding direction is less than one. A sheet conveying device according to claim 9;
An image reading sensor that is provided in the main body and reads an image of a sheet;
A reference plate provided at a position facing the image reading position of the image reading sensor of the opposing unit, and read by the image reading sensor when calibrating image reading conditions;
The image reading apparatus according to claim 1, wherein the reference plate is provided with a density difference in a sliding direction of the opposing unit.   An image reading apparatus comprising the sheet conveying apparatus according to claim 1, further comprising an image reading unit configured to read an image of a sheet conveyed by the sheet conveying apparatus.   An image forming apparatus comprising the sheet conveying apparatus according to claim 1, further comprising an image forming unit that forms an image on a sheet conveyed by the sheet conveying apparatus.

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