Image reading device and image forming apparatus

Abstract

To provide an image reading device that can read an image of a document with a size longer than a predetermined size in a document fixation system.SOLUTION: An image reading device comprises: a document platen 41; a reading unit that scans a placed document in a main scanning direction to read an image; a reading unit moving section that moves the reading unit in a reading direction along a sub-scanning direction intersecting the main scanning direction and a direction opposite thereto from a home position; a cursor 47 that is abutted with an edge, on a reading starting side in the sub-scanning direction, of the document placed on the document platen 41; and a cursor moving section 49 that reciprocates the cursor 47 along the sub-scanning direction. The cursor moving section 49 can extend an image readable range in the sub-scanning direction by moving the cursor 47 in the opposite direction from a reference position in conjunction with the movement of the reading unit in the opposite direction from the home position.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to an image reading device that reads an image of a document placed on a document table, and an image forming apparatus that includes the image reading device. [Background technology]

[0002] Image reading devices may be configured to read images of documents using two types of document reading methods: a sheet-through method and a fixed document method. In the sheet-through method, a document is automatically transported to a reading position on a document table by a document transport device, and the image of the document is read by a reading sensor at the reading position. In the fixed document method, a document is placed on the document table, and the image of the placed document is read by moving the reading sensor.

[0003] To position the document in the fixed document method, the image reading device is equipped with a stop reference plate that regulates the document reading start position, as described in Patent Document 1. The user places the document on the document table and positions it by stopping the edge of the document from which reading will begin against the stop reference plate. The reading sensor then moves to read the image of the placed document. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-078720 Summary of the Invention [Problem to be solved by the invention]

[0005] In the image reading device described above, the reference plate is immovable, so the size of the document that can be placed is limited. For example, the maximum size is the size of an A4-size (210 mm x 297 mm) document placed vertically (the longitudinal direction of the document is along the sub-scanning direction). In this case, there is a problem that it is impossible to read, for example, a legal-size (215.9 mm x 355.6 mm) document using the fixed document method.

[0006] SUMMARY OF THE INVENTION In consideration of the above circumstances, it is an object of the present invention to provide an image reading device and an image forming device that are capable of reading an image on a document that is longer than a predetermined size in a document fixed system. [Means for solving the problem]

[0007] In order to achieve the above object, the image reading device of the present invention comprises a document table on which a document is placed, a reading unit arranged below the document table and configured to scan the placed document in a main scanning direction to read an image, a reading unit movement section which moves the reading unit from a home position in a reading direction along a sub-scanning direction that intersects with the main scanning direction and in the opposite direction, a cursor against which the edge of the document placed on the document table at the start of reading in the sub-scanning direction is abutted, and a cursor movement section which moves the cursor back and forth along the sub-scanning direction, wherein the cursor movement section moves the cursor from a reference position in the opposite direction in conjunction with the movement of the reading unit from the home position in the opposite direction, thereby making it possible to extend the image readable range in the sub-scanning direction.

[0008] In the present invention, the reading unit may include an image reading sensor, a holder that supports the reading sensor, and a reading unit side rack gear that is provided on the holder along the sub-scanning direction, and the cursor moving section may include a drive gear that can mesh with the reading side rack gear, a one-way clutch that is provided coaxially with the drive gear, a cursor side rack gear that is provided on the cursor along the sub-scanning direction, a pulley that can mesh with the cursor side rack gear, and a timing belt that connects the pulley and the one-way clutch, and when the reading unit passes a predetermined position in the opposite direction from a home position, the reading unit side rack gear meshes with the drive gear to rotate the drive gear, and the rotation of the drive gear is transmitted from the one-way clutch to the pulley via the timing belt, and the rotation of the pulley moves the cursor in the opposite direction together with the cursor side rack gear.

[0009] In the present invention, the cursor movement unit may further include a fixing mechanism that fixes the cursor side rack gear so that it cannot move when the cursor moves to a position away from the reference position in the opposite direction, and a biasing member that biases the pulley in a direction opposite to the rotational direction of the one-way clutch, and when the fixing of the cursor side rack gear by the fixing mechanism is released, the biasing member causes the pulley to rotate, and the cursor returns to the reference position together with the cursor side rack gear.

[0010] In the present invention, the reading unit moving section may be characterized in that after moving the reading unit in the opposite direction, it moves the reading unit in the reading direction until the reading unit side rack gear separates from the drive gear, and then image reading by the reading unit begins.

[0011] The image forming apparatus of the present invention may be characterized by including the image reading device and an image forming section that forms an image on a sheet based on image data of a document read by the image reading device. [Effects of the Invention]

[0012] According to the present invention, the cursor moving unit moves the cursor in the opposite direction in conjunction with the movement of the reading unit in the opposite direction to the reading direction, thereby making it possible to extend the image reading range of the document positioned by the cursor in the sub-scanning direction. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a front view schematically illustrating an internal structure of an image forming apparatus according to an embodiment of the present invention. [Figure 2] 1 is a perspective view showing a reading unit of an image reading device according to an embodiment of the present invention; [Figure 3] FIG. 2 is a front view showing a reading unit moving section of the image reading device according to the embodiment of the present invention. [Figure 4] FIG. 2 is a plan view showing a cursor of the image reading device according to the embodiment of the present invention. [Figure 5A] 1 is a perspective view showing a front end portion of a cursor of an image forming apparatus according to an embodiment of the present invention; [Figure 5B] FIG. 2 is a perspective view showing the rear end of a cursor of the image forming apparatus according to the embodiment of the present invention. [Figure 6] 1 is a perspective view showing a cursor movement unit of an image reading device according to an embodiment of the present invention; [Figure 7] 1 is a front view schematically showing a cursor movement unit of an image reading device according to an embodiment of the present invention; [Figure 8] 2 is a cross-sectional view showing a reading unit (home position) and a cursor (first reference position) in the image reading device according to one embodiment of the present invention. FIG. [Figure 9] 2 is a cross-sectional view showing a reading unit (at a conveyed document reading position) and a cursor (at a first reference position) in an image reading device according to one embodiment of the present invention. FIG. [Figure 10]1 is a cross-sectional view showing a reading unit (from a transported document reading position to a maximum opposite position) and a cursor (from a first reference position to a second reference position) in an image reading device according to an embodiment of the present invention. [Figure 11] 4 is a cross-sectional view showing the reading unit (at the maximum opposite position) and the cursor (at the second reference position) in the image reading device according to one embodiment of the present invention. FIG. [Figure 12] 4 is a cross-sectional view showing the reading unit (legal reading start position) and the cursor (second reference position) in the image reading device according to one embodiment of the present invention. FIG. [Figure 13] 2 is a plan view showing the positions of a reading unit and a cursor in the image reading device according to the embodiment of the present invention; FIG. DETAILED DESCRIPTION OF THE INVENTION

[0014] An image reading apparatus and an image forming apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

[0015] First, the image forming apparatus 1 will be described with reference to Fig. 1. Fig. 1 is a front view schematically showing the internal configuration of the image forming apparatus 1. In each drawing, Fr, Rr, L, and R indicate the front, rear, left, and right sides of the image forming apparatus 1, respectively.

[0016] The image forming apparatus 1 includes an image forming unit 3 that forms an image on a sheet, and an image reading unit 5 that is disposed above the image forming unit 3 and reads the image (original) formed by the image forming unit 3.

[0017] First, we will explain the image forming unit 3. The image forming unit 3 includes a plurality of paper feed cassettes 11, a plurality of paper feed devices 13 that feed sheets from the plurality of paper feed cassettes 11, a toner image forming unit 15 that forms a toner image on the sheet, a fixing unit 17 that fixes the toner image on the sheet, and a discharge unit 19 that discharges the sheet. The image forming unit 3 also includes a discharge tray 21 formed below the discharge unit 19. The image forming unit 3 also includes a transport path 23 along which the sheet is transported from each paper feed device 13, through the toner image forming unit 15 and the fixing unit 17, toward the discharge unit 19.

[0018] A sheet fed from one of the paper feed cassettes 11 by the corresponding paper feed device 13 is transported along a transport path 23 to a toner image forming unit 15. The toner image forming unit 15 forms a toner image on the sheet based on the image read by the image reading unit 5. The sheet on which the toner image has been formed is transported along the transport path 23 to a fixing unit 17. The fixing unit 17 fixes the toner image on the sheet. The sheet is then discharged from a discharge unit 19 and stacked on a discharge tray 21.

[0019] Next, we will explain the image reading unit 5. The image reading unit 5 includes a reading unit 31 that reads an image of a document, and a transport unit 33 that is disposed above the reading unit 31 and transports the document to the reading unit 31.

[0020] First, the reading unit 31 will be described with reference to FIG. 2. FIG. 2 is a perspective view showing the reading unit 31. The reading unit 31 includes a document table 41 on which a document is placed, a reading unit 43 (see FIG. 1) arranged below the document table 41, a reading unit moving section 45 (not shown in FIGS. 1 and 2, but will be described later with reference to FIG. 3) that moves the reading unit 43 back and forth, a cursor 47 (see FIG. 2) that positions the document placed on the document table 41, and a cursor moving section 49 (see FIG. 2) that moves the cursor 47 back and forth. These components are supported by a housing 51.

[0021] First, the housing 51 will be described. As shown in FIG. 2, the housing 51 has a rectangular box shape composed of a top plate 61, a bottom plate, front and rear side plates, and left and right side plates. A substantially rectangular opening 63 that is long in the left-right direction is formed in the top plate 61. The opening 63 has a rectangular main opening 63a and a rectangular left opening 63b that is longer in the front-to-rear direction than the main opening 63a. With this configuration, front and rear step surfaces 63c are formed along the front-to-rear direction between the front and rear side surfaces of the main opening 63a and the front and rear side surfaces of the left opening 63b.

[0022] 2, front and rear rails 65F, 65R are formed along the left-right direction at the front and rear edges of the left opening 63b. The front and rear rails 65F, 65R are L-shaped in side view, with upright walls standing upright from the front and rear edges of the left opening 63b and horizontal walls bending in opposing directions from the upper ends of the upright walls. In addition, a bent piece (not shown) bending downward from the tip is formed on the horizontal wall of the front rail 65F.

[0023] Next, the document table 41 will be described with reference to FIG. 2. The document table 41 is rectangular and made of transparent glass. The document table 41 is supported by the housing 51 so as to be exposed to an opening 63 from below a top plate 61 of the housing 51. A portion 41X exposed from a main opening 63a of the opening 63 is an original placement surface on which an original is placed in the document fixed method. A portion 41Y exposed from a left opening 63b of the opening 63 is a reading position where an image of the original is read in the sheet-through method.

[0024] Next, the reading unit 43 will be described with reference to FIG. 1. The reading unit 43 includes a contact image sensor (CIS) 71 and a holder 73 that holds the CIS 71. The CIS 71 includes a light source that irradiates light toward the image to be read and a number of light receiving elements that photoelectrically convert light reflected from the document. The number of light receiving elements are aligned in the main scanning direction X1, which in this example is the front-to-rear direction. A reading unit side rack gear 75 is formed in the center of the front-to-rear direction of the holder 73, facing downward and aligned along the sub-scanning direction X2 (left-to-right direction in this example) that is perpendicular to the main scanning direction X1.

[0025] Next, the reading unit moving section 45 will be described with reference to FIG. 3. FIG. 3 is a side view that schematically shows the reading unit moving section 45. The reading unit moving section 45 moves the reading unit 43 from the home position HP in a reading direction Y1 (to the right in this example) along the sub-scanning direction X2 (left-right direction) and in the opposite direction Y2 (to the left in this example). The home position HP is a position below the left end of the document placement surface of the document table 41 (portion 41X exposed from the main opening 63a in FIG. 2), and is the position where document reading begins when using the document fixing method.

[0026] The reading unit moving section 45 includes a drive pulley 81 and a driven pulley 83 spaced apart in the sub-scanning direction X2, a motor 85 that rotates the drive pulley 81, and a timing belt 87 wound around the pulleys 81 and 83. The drive pulley 81 is supported at one end (the right end in this example) in the sub-scanning direction X2 so as to be rotatable about a rotation axis extending in the vertical direction. The motor 85 rotates the drive pulley in one direction and the other. The driven pulley 83 is supported at the other end (the left end in this example) in the sub-scanning direction X2 so as to be rotatable about a rotation axis extending in the vertical direction. The timing belt 87 is wound around the rotation axis of the drive pulley 81 and the driven pulley 83. The holder 73 of the reading unit 43 is connected to the track portion on the front side of the timing belt 87.

[0027] The drive pulley 81 is driven by the motor 85 to rotate in one direction and the other, causing the timing belt 87 to circulate in one direction and the other, and the reading unit 43 to move back and forth along the sub-scanning direction X2. Specifically, when the drive pulley 81 rotates a predetermined number of times in the counterclockwise direction CCW in FIG. 3, the timing belt 87 circulates in the counterclockwise direction, and the reading unit 43 moves in the reading direction Y1 from the home position HP to a predetermined movement end position P1. This enables the image of a document placed on the document placement surface to be read in the fixed document method. On the other hand, when the drive pulley 81 rotates a predetermined number of times in the clockwise direction CW in FIG. 3, the timing belt 87 circulates in the clockwise direction, and the reading unit 43 moves in the opposite direction Y2 from the home position HP to a transported document reading position P2 below the reading position in the sheet-through method. This enables the image of a document transported to the reading position to be read in the sheet-through method.

[0028] In this way, the reading unit 43 is movable from the home position HP in the reading direction Y1, and is also movable from the home position HP in the direction Y2 opposite to the reading direction Y1.

[0029] Next, the cursor 47 will be described with reference to FIGS. 2, 4, 5A, and 5B. FIG. 4 is a perspective view of the cursor 47, and FIGS. 5A and 5B are perspective views showing the end of the cursor 47. The cursor 47 has a plate-shaped main body 91 whose length in the front-to-rear direction is equal to the length of the platen 41, and a guide portion 93 whose cross-sectional shape is triangular and whose length is equal to that of the main body 91. The top and bottom surfaces of the main body 91 are horizontal. One long side surface of the main body 91 is formed perpendicular to the top and bottom surfaces. This long side surface is an abutment surface 95 against which the edge of the document on the reading start side in the sub-scanning direction X2 abuts. A scale indicating the size of the document is marked on the top surface of the main body 91. The scale indicates the length (length along the main scanning direction X1) of a document of a given size from a reference position Z (see FIG. 4) at one end in the longitudinal direction. A shading plate (not shown) for adjusting the CIS is embedded in the lower surface of the main body 91.

[0030] The guide portion 93 is fixed to the long side surface opposite the abutment surface 95 of the main body portion 91. The underside of the guide portion 93 is continuous with the underside of the main body portion 91. The guide portion 93 is taller than the main body portion 91 and has a guide surface that is inclined upward toward the main body portion 91. A document that has passed the reading position in the sheet-through method is guided downstream along this guide surface.

[0031] 5A, two guide walls 97 are formed along the left-right direction on the upper surface of the front end of the main body 91, standing at a predetermined distance in the front-rear direction. Furthermore, a cursor-side rack gear 99 is provided on the lower surface of the front end of the main body 91, facing downward along the left-right direction. The cursor-side rack gear 99 extends from the lower surface of the main body 91 in the direction opposite to the guide part 93.

[0032] As shown in Fig. 5B, two recesses are formed on the upper surface of the rear end of the main body 91, spaced apart in the left-right direction. Each recess houses a pulley 101 that can rotate about a rotation axis along the front-to-rear direction, protruding from the upper surface. Furthermore, a locking piece 103 is formed on the upper surface, inside (toward the center) of the recesses. The locking piece 103 has an upright wall that rises vertically from the upper surface and a horizontal wall that bends rearward from the upper end of the upright wall.

[0033] As shown in FIG. 2, cursor 47 is placed on the upper surface of platen 41 in a position along the main scanning direction X1 (front-rear direction). The rear end of main body 91 fits under the horizontal wall of rear rail 65R provided on top plate 61 of housing 51, and locking piece 103 (see FIG. 5B) provided on the upper surface of main body 91 rests on the horizontal wall of rear rail 65R. In addition, cursor-side rack gear 99 (see FIG. 5A) provided on the front end of main body 91 protrudes downward from the front of platen 41 (see FIG. 6). Furthermore, a bent piece of front rail 65F provided on top plate 61 of housing 51 fits between two guide walls 97 provided on the upper surface of the front end of main body 91.

[0034] In this way, the cursor 47 is movable on the top surface of the platen 41 in the sub-scanning direction X2 (left-right direction). Specifically, the cursor 47 is movable in the opposite direction Y2 (leftward) from a first reference position R1 (see the solid line in FIG. 2 ) where the abutment surface 95 abuts against the stepped surface 63 c of the top panel 61 of the housing 51 to a second reference position R2 (see the two-dot chain line in FIG. 2 ) where the left edge of the guide portion 93 abuts against the left side surface 63 d of the left opening 63 b of the top panel 61 of the housing 51. By moving the abutment surface 95 in the opposite direction Y2 in this way, the size of the document that can be placed on the platen 41 can be extended in the sub-scanning direction X2. For example, an A4 portrait-sized document can be placed at the first reference position R1, and a legal-sized document can be placed at the second reference position R2.

[0035] The first reference position R1 is a position downstream of the home position HP of the reading unit 43 in the reading direction Y1.

[0036] Next, the cursor movement unit 49 will be described with reference to Figs. 6 and 7. Fig. 6 is a perspective view showing the cursor movement unit 49, and Fig. 7 is a front view showing the cursor movement unit 49. The cursor movement unit 49 moves the cursor 47 back and forth along the sub-scanning direction X2 (left-right direction). In particular, the cursor movement unit 49 moves the cursor 47 from the first reference position R1 to the second reference position R2 in conjunction with the movement of the reading unit 43 from the home position HP in the opposite direction Y2 (leftward).

[0037] The cursor moving unit 49 includes a drive gear 111 that can mesh with the reading unit side rack gear 75 of the reading unit 43, a one-way clutch 115 provided on the rotating shaft 113 of the drive gear 111, a pulley 117, a timing belt 119 that connects the pulley 117 and the one-way clutch 115, a fixing mechanism 121 for the cursor 47, and a spiral spring 123 that is arranged between the pulley 117 and the housing 51.

[0038] First, the drive gear 111 will be described. The drive gear 111 is disposed at the left end inside the housing 51 and is supported so as to be rotatable integrally with a rotation shaft 113 that extends in the front-to-rear direction. When the reading unit 43 has moved to the home position HP, the reading-unit-side rack gear 75 of the holder 73 and the drive gear 111 are not engaged. After the reading unit 43 moves in the opposite direction Y2 from the home position HP and passes below the reading position in the sheet-through method, the reading-unit-side rack gear 75 of the holder 73 engages with the drive gear 111. Then, when the reading unit 43 moves further in the opposite direction Y2, the drive gear 111 rotates counterclockwise CCW.

[0039] Next, we will explain the one-way clutch 115. The one-way clutch 115 is fixed to the other end of the rotary shaft 113. Only the rotational force in the counterclockwise direction CCW of the rotary shaft 113 is transmitted to the one-way clutch 115, causing it to rotate in the counterclockwise direction, but the rotational force in the clockwise direction of the rotary shaft 113 is not transmitted to the one-way clutch 115.

[0040] Next, the pulley 117 will be described. The pulley 117 is disposed so as to mesh with a cursor-side rack gear 99 provided on the cursor 47, and is supported by the housing 51 so as to be rotatable about a rotation axis along the front-to-rear direction. In other words, when the pulley 117 rotates, the cursor-side rack gear 99, i.e., the cursor 47, moves in the left-right direction (sub-scanning direction X2).

[0041] Next, a description will be given of the timing belt 119. The timing belt 119 is wound around the pulley 117 and the one-way clutch 115, and transmits the rotation of the one-way clutch 115 to the pulley 117.

[0042] When the drive gear 111 rotates counterclockwise (CCW), causing the rotary shaft 113 to rotate counterclockwise (CCW), the counterclockwise rotation of the rotary shaft 113 is transmitted to the one-way clutch 115, causing the one-way clutch 115 to rotate counterclockwise (CCW). The rotation of the one-way clutch 115 is transmitted to the pulley 117 via the timing belt 119, causing the pulley 117 to rotate counterclockwise (CCW). As a result, the cursor 47 moves in the opposite direction Y2 (leftward) together with the cursor-side rack gear 99. On the other hand, when the drive gear 111 rotates clockwise (CW), causing the rotary shaft 113 to rotate clockwise (CW), the clockwise rotation of the rotary shaft 113 is not transmitted to the one-way clutch 115, and the one-way clutch 115 does not rotate. That is, the cursor 47 does not move either.

[0043] Next, the fixing mechanism 121 will be described with reference to Fig. 7. The fixing mechanism 121 meshes with the cursor-side rack gear 99 when the cursor 47 moves to the second reference position R2, thereby fixing the cursor-side rack gear 99, i.e., the cursor 47, so that it cannot move. The fixing mechanism 121 includes gear teeth 131 that can mesh with the cursor-side rack gear 99, and a button 133 that is provided integrally with the gear teeth 131.

[0044] The gear teeth 131 have a generally triangular shape in cross section that can engage with the tooth grooves of the cursor-side rack gear 99. The button 133 is disposed in an opening formed in the top plate 61 of the housing 51, and is biased upward by a coil spring 135. The gear teeth 131 are provided integrally with the button 133 by an arm 137.

[0045] When the cursor 47 moves to the second reference position R2, the gear teeth 131 engage with the tooth groove of the cursor side rack gear 99 in the most opposite direction Y2, restricting the movement of the cursor side rack gear 99. On the other hand, when the button 133 is pressed, the gear teeth 131 move downward away from the cursor side rack gear 99 (see the two-dot chain line in FIG. 7), allowing the cursor side rack gear 99, i.e., the cursor 47, to move.

[0046] Next, spiral spring 123 will be described with reference to Figure 6. The center end of spiral spring 123 is fixed to the rotation shaft of pulley 117, and the outer end is fixed to housing 51. When pulley 117 rotates counterclockwise (CCW), spiral spring 123 is wound up and deformed so that its outer diameter decreases. Thereafter, when the force rotating pulley 117 is released, spiral spring 123 deforms so that its outer diameter increases. As a result of this deformation, spiral spring 123 is unwound, causing pulley 117 to rotate clockwise.

[0047] Next, referring again to FIG. 1 , the transport unit 33 will be described. The transport unit 33 has a transport path 145 that transports a document placed on the document tray 141 to the discharge tray 143 via the reading position. At the reading position, a reading guide 147 is supported so as to be movable in the vertical direction. The transport unit 33 is rotatable in the vertical direction around a support shaft provided at the rear end of the reading unit 31. When the transport unit 33 is rotated upward, the document table 41 is opened, allowing a document to be placed on the document table 41 or removed from the document table 41. When the transport unit 33 is rotated downward, the document placed on the document table 41 is fixed by the transport unit 33.

[0048] The image reading operation (document fixed method) in the reading section 31 having the above configuration will be described with reference to Fig. 2 etc. and Figs. 8 to 12. Figs. 8 to 11 are front views showing the cursor 47 and the reading unit 43. Fig. 12 is a plan view showing the positions of the cursor 47 and the reading unit 43.

[0049] As shown in FIG. 8 , in the standby state, the reading unit 43 is moved to the home position HP. The cursor 47 is located at the first reference position R1. As described above, the first reference position R1 is located downstream of the home position HP of the reading unit 43 in the reading direction Y1. When reading an image of an A4-sized document, the transport unit 33 is rotated upward to expose the document table 41, and the document is placed on the document placement surface. At this time, the left rear corner of the document is positioned to align with the angle between the side of the main opening 63a of the top panel 61 of the housing 51 and the abutment surface 95 of the cursor 47. The transport unit 33 is then closed to secure the document on the document table 41.

[0050] When a command to start reading is given, the motor 85 (see FIG. 3) of the reading unit moving section 45 is driven, causing the drive pulley 81 to rotate counterclockwise CCW. This causes the timing belt 87 to run counterclockwise, and the reading unit 43, with the holder 73 fixed to the timing belt 87, moves from the home position HP in the reading direction Y1. The reading unit 43 moves to the movement end position P1, causing the image of the document to be read by the CIS 71. After the reading unit 43 moves to the movement end position P1 (see FIG. 13), the motor 85 stops, and then the motor 85 is driven to rotate the drive pulley 81 clockwise CW, causing the timing belt 87 to run clockwise, and the reading unit 43 returns to the home position HP.

[0051] Next, the case of reading a legal-size document will be described. When information that the document size is legal is input, first, motor 85 (see FIG. 3) of reading unit movement section 45 is driven to drive drive pulley 81 in the clockwise direction CW. Then, timing belt 87 runs clockwise, and reading unit 43 starts to move in the opposite direction Y2.

[0052] 9, when the reading unit 43 moves in the opposite direction Y2 to the transported document reading position P2, the reading-unit-side rack gear 75 meshes with the drive gear 111 of the cursor movement section 49. Then, as shown in FIG. 6, the drive gear 111 rotates counterclockwise CCW, and the rotation shaft 113 rotates counterclockwise CCW together with the drive gear 111. The counterclockwise CCW rotation of the rotation shaft 113 is transmitted to the one-way clutch 115, which rotates counterclockwise CCW. The rotation of the one-way clutch 115 is transmitted to the pulley 117 via the timing belt 119, which rotates the pulley 117 counterclockwise CCW. As a result, the cursor 47 starts to move in the opposite direction Y2 from the first reference position R1 together with the cursor-side rack gear 99 meshing with the pulley 117. Furthermore, as pulley 117 rotates, spiral spring 123 is wound up and deformed so that its outer diameter becomes smaller.

[0053] At this time, the front and rear ends of the cursor 47 are guided by the front and rear rails 65F, 65R provided on the housing 51. At the front end of the cursor 47, the bent piece of the front rail 65F fits between two guide walls 97 (see FIG. 5A) provided on the upper surface of the main body 91. This allows the cursor 47 to be reliably guided in the left-right direction (sub-scanning direction X2). At the rear end of the cursor 47, the horizontal wall of the locking piece 103 (see FIG. 5B) provided on the main body 91 rests on the horizontal wall of the rear rail 65R, and the two pulleys 101 abut against the lower surface of the horizontal wall, thereby reducing friction between the cursor 47 and the rail 65R. In this way, the cursor 47 moves stably in the left-right direction (sub-scanning direction X2).

[0054] The reading unit 43 moves further in the opposite direction Y2 beyond the area below the reading position. As the reading unit 43 moves, the cursor 47 also moves further in the opposite direction Y2 together with the cursor-side rack gear 99. As shown in FIG. 10 , when the cursor 47 passes the reading position, the reading guide 147 of the transport section 33 is pushed up by the guide section 93 of the cursor 47.

[0055] 11, when the reading unit 43 moves to the maximum opposite position P3, the motor 85 of the reading unit moving section 45 stops. As the reading unit 43 moves, the cursor 47 moves to the second reference position R2. At the second reference position R2, the cursor 47 is immovably fixed by the fixing mechanism 121, as described above. That is, the gear teeth 131 of the fixing mechanism 121 engage with the tooth grooves of the cursor-side rack gear 99.

[0056] Thereafter, the motor 85 of the reading unit moving section 45 is driven to rotate the drive pulley 81 counterclockwise CCW, the timing belt 87 runs counterclockwise, and the reading unit 43 moves from the maximum opposite position P3 in the reading direction Y1. As shown in FIG. 12, the reading unit 43 moves until the reading unit side rack gear 75 separates from the drive gear 111 of the cursor moving section 49. The position of the reading unit 43 at this time is defined as the legal reading start position P4 (see FIG. 12). The legal reading start position P4 is a position between the maximum opposite position P3 and the transported document reading position P2, and is a position upstream of the second reference position R2 of the cursor 47 in the reading direction Y1.

[0057] 6, when the reading unit 43 moves in the reading direction Y1, the drive gear 111 meshing with the reading unit side rack gear 75 rotates in the clockwise direction CW, and the rotating shaft 113 rotates in the clockwise direction CW. At this time, the clockwise rotation of the rotating shaft 113 is not transmitted to the one-way clutch 115, so the one-way clutch 115 does not rotate. In other words, the rotational force of the rotating shaft 113 is not transmitted to the pulley 117.

[0058] Thereafter, the transport unit 33 is opened to expose the document table 41, and the document is placed on the document placement surface. At this time, the left rear corner of the document is positioned to align with the corner between the side of the main opening 63a of the top panel 61 of the housing 51 and the abutment surface 95 of the cursor 47. Thereafter, the transport unit 33 is rotated downward.

[0059] Then, when an instruction to start reading is given, the motor 85 of the reading unit moving section 45 is driven, and the drive pulley 81 rotates counterclockwise CCW (see FIG. 3). This causes the timing belt 87 to run counterclockwise CCW, and the reading unit 43 moves from the legal reading start position P4 in the reading direction Y1. The reading unit 43 moves to the movement end position P1, and the image of the document is read by the reading unit 43. After the reading unit 43 moves to the movement end position P1, the motor 85 stops, and then the motor 85 is driven, and the drive pulley 81 rotates clockwise CW, and the timing belt 87 runs clockwise CW, and the reading unit 43 returns to the home position HP.

[0060] After the legal-size document has been read, button 133 of fixing mechanism 121 is pressed down, as shown in FIG. 7 . This moves gear teeth 131 downward away from cursor-side rack gear 99. This releases cursor-side rack gear 99, i.e., cursor 47, allowing pulley 107 to rotate freely. This unwinds spiral spring 123, deforming it so that its outer diameter increases, causing pulley 117 to rotate clockwise. As a result, cursor 47 moves in reading direction Y1 together with cursor-side rack gear 99. Cursor 47 returns to first reference position R1, where abutment surface 95 abuts against step surface 63c of opening 63 in top panel 61 of housing 51. In this manner, spiral spring 123 is an example of a biasing member that biases one-way clutch 115 in the direction opposite to its rotational direction.

[0061] As described above, according to the present invention, the cursor movement unit 49 moves the cursor 47 in the opposite direction Y2 to the reading direction Y1 in conjunction with movement of the reading unit 43 in the opposite direction Y2. This makes it possible to lengthen the image reading range of the document positioned by the cursor 47 in the sub-scanning direction X2. For example, if the cursor 47 is provided to fit an A4 portrait-sized document, the cursor 47 can be moved to a position where a legal-sized document can be read.

[0062] 13, for an A4 portrait size document, the position on the side where reading starts is the first reference position R1, and the reading unit 43 moves from the HP to the movement end position P1 to read the image of the document (movement distance W1). For a legal size document, the position on the side where reading starts is the second reference position R2, and the reading unit 43 moves from the legal reading start position P4 to the movement end position P1 to read the image of the document (movement distance W2>W1).

[0063] Furthermore, the cursor movement unit 49 moves the cursor 47 in the opposite direction Y2 only in conjunction with movement of the reading unit 43 in the opposite direction Y2, and is not linked to movement of the reading unit 43 in the reading direction Y1. Therefore, during image reading, the reading unit 43 can be stably moved in the reading direction Y1 while maintaining the cursor 47 at a predetermined reference position. Meanwhile, by simply pressing the button 133, the spiral spring 123 of the cursor movement unit 49 can be used to move the cursor 47 in the reading direction Y1 and automatically return it to the first reference position R1.

[0064] The document positioned at the second reference position R2 may be a document other than a legal size document.

[0065] Although the present invention has been described with reference to specific embodiments, the present invention is not limited to the above embodiments, and those skilled in the art may modify the above embodiments without departing from the scope and spirit of the present invention. [Explanation of symbols]

[0066] 1. Image forming device 3 Image forming unit 31 Reading unit (image reading device) 41 manuscript table 43 Reading unit 45 Reading unit moving part 47 Cursor 49 Cursor movement section 71 Image reading sensor 73 Holder 75 Reading unit side rack gear 111 Drive gear 115 One-way clutch 117 Pulley 119 Timing Belt 121 Fixing mechanism 123 Spiral spring (biasing member)

Claims

1. a document table on which a document is placed; a reading unit disposed below the document table, for scanning the document placed thereon in a main scanning direction to read an image; a reading unit moving section that moves the reading unit from a home position in a reading direction along a sub-scanning direction intersecting the main scanning direction and in the opposite direction; a cursor against which an edge of the document placed on the document table on a side where reading starts in the sub-scanning direction is abutted; a cursor moving unit that moves the cursor back and forth along the sub-scanning direction, An image reading device characterized in that the cursor movement unit moves the cursor from a reference position in the opposite direction in conjunction with the movement of the reading unit from a home position in the opposite direction, thereby making it possible to extend the image readable range in the sub-scanning direction.

2. The reading unit includes: an image reading sensor; a holder for supporting the read sensor; a reading unit side rack gear provided in the holder along the sub-scanning direction, The cursor movement unit a drive gear capable of meshing with the reading-side rack gear; a one-way clutch provided coaxially with the drive gear; a cursor-side rack gear provided on the cursor along the sub-scanning direction; a pulley that can mesh with the cursor side rack gear; a timing belt connecting the pulley and the one-way clutch; Equipped with 2. The image reading device according to claim 1, wherein when the reading unit passes a predetermined position in the opposite direction from the home position, the reading unit side rack gear meshes with the drive gear, causing the drive gear to rotate, and the rotation of the drive gear is transmitted from the one-way clutch to the pulley via the timing belt, causing the pulley to rotate, thereby moving the cursor in the opposite direction together with the cursor side rack gear.

3. The cursor movement unit a fixing mechanism that fixes the cursor-side rack gear so as to be immovable when the cursor moves to a position away from the reference position in the opposite direction; a biasing member that biases the pulley in a direction opposite to the rotation direction of the one-way clutch, 3. The image reading device according to claim 2, wherein when the fixing mechanism releases the cursor-side rack gear, the biasing member rotates the pulley, and the cursor returns to the reference position together with the cursor-side rack gear.

4. The image reading device described in claim 2, characterized in that after moving the reading unit in the opposite direction, the reading unit moving section moves the reading unit in the reading direction until the reading unit side rack gear separates from the drive gear, and then image reading by the reading unit begins.

5. The image reading device according to claim 1; an image forming section that forms an image on a sheet based on image data of the document read by the image reading device.

Images