Document transport device

Abstract

To provide a document feeder capable of preventing postural change and deformation of a paper feed tray when a document is loaded.SOLUTION: A document feeder 120 comprises: a paper feed tray 44 on which a document is stacked; a discharge tray 43 which is disposed below the paper feed tray 44; a delivery roller which delivers the document one by one from the paper feed tray 44; a first lifting mechanism 33 which supports both ends of the paper feed tray 44 in a width direction crossing a document conveyance direction Z, and lifts / lowers the paper feed tray 44 so that a top surface of the document is brought into contact with the delivery roller; a conveyance mechanism 32 which conveys the document delivered by the delivery roller to the discharge tray 43 via a reading position; a support member 23 which supports the paper feed tray 44 on the upstream side of the first lifting mechanism 33 in the conveyance direction Z; and a second lifting mechanism which lifts / lowers the support member 23 in synchronization with the paper feed tray 44.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a document transport device that transports a document to a reading position. [Background technology]

[0002] In recent years, there has been an increasing demand for a document transport device provided in a document reading device with a larger capacity, and technologies for realizing this are being considered. For example, Patent Document 1 proposes that a sheet transport mechanism transports stacked sheets on a liftable paper feed tray to an ejection tray, thereby raising the paper feed tray and expanding the stacking space between the ejection tray and the paper feed tray. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-167545 Summary of the Invention [Problem to be solved by the invention]

[0004] In the configuration described in Patent Document 1, a downstream portion of the paper feed tray in the transport direction is supported on the main body of the document feeder so as to be able to move up and down. Because the center of gravity of a stack of sheets loaded on the paper feed tray is located upstream of the supported portion of the paper feed tray in the transport direction, a downward bending moment acts on the paper feed tray with the supported portion as a fulcrum. The larger the size of the sheets in the transport direction, the greater the bending moment, since the center of gravity is located further upstream in the transport direction. As the number of sheets that can be loaded on the paper feed tray increases due to increased capacity, the paper feed tray may change in position or become deformed, potentially reducing the accuracy of transport.

[0005] SUMMARY OF THE INVENTION In consideration of the above circumstances, an object of the present invention is to provide a document transport device that can suppress changes in the posture and deformation of a paper feed tray when documents are loaded. [Means for solving the problem]

[0006] In order to solve the above problem, the document transport device of the present invention comprises a paper feed tray on which documents are loaded, an output tray provided below the paper feed tray, a feed roller that feeds the documents one by one from the paper feed tray, a first lifting mechanism that supports both ends of the paper feed tray in a width direction that intersects with the document transport direction and raises and lowers the paper feed tray so that the top surface of the document contacts the feed roller, a transport mechanism that transports the document fed by the feed roller to the output tray via a reading position, a support member that supports the paper feed tray upstream of the first lifting mechanism in the transport direction, and a second lifting mechanism that raises and lowers the support member in synchronization with the paper feed tray.

[0007] The support member may support a rear end of the paper feed tray in the width direction.

[0008] The support member may be in contact with the lower surface of the paper feed tray.

[0009] The document transport device may include a drive unit that drives the first lifting mechanism, and a distribution unit that distributes a driving force generated by the drive unit to the second lifting mechanism.

[0010] The second lifting mechanism may include a pinion that rotates by the driving force distributed from the distribution section, and a rack that is arranged with the vertical direction as its longitudinal direction and engages with the pinion, and the support member may be connected to the rack. [Effects of the Invention]

[0011] According to the present invention, it is possible to suppress changes in the posture and deformation of the paper feed tray when documents are loaded. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a front view schematically illustrating an internal configuration of an image forming apparatus according to an embodiment of the present invention. [Figure 2]1 is a perspective view showing the appearance of a document transport device according to an embodiment of the present invention; [Figure 3] FIG. 2 is a perspective view showing a support member and its surrounding area according to an embodiment of the present invention. [Figure 4] FIG. 2 is a front view schematically showing a paper feed mechanism and a transport mechanism according to an embodiment of the present invention. [Figure 5] FIG. 2 is a front view schematically showing a transport mechanism and a first lifting mechanism according to an embodiment of the present invention. [Figure 6] FIG. 2 is a front view schematically showing a transport mechanism and a first lifting mechanism according to an embodiment of the present invention. [Figure 7] FIG. 4 is a rear view schematically showing a second lifting mechanism and a drive unit according to an embodiment of the present invention. [Figure 8] FIG. 8 is an enlarged view of the main part of FIG. 7. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, a document transport device 120 and an image forming apparatus 100 according to an embodiment of the present invention will be described with reference to the drawings.

[0014] First, the overall configuration of image forming apparatus 100 will be described. Fig. 1 is a front view that schematically shows the internal configuration of image forming apparatus 100. In the following description, the front side of the paper in Fig. 1 is the front side (front side) of image forming apparatus 100, and left and right directions will be described based on the direction when image forming apparatus 100 is viewed from the front. In each figure, U, Lo, L, R, Fr, and Rr represent up, down, left, right, front, and rear, respectively.

[0015] The image forming apparatus 100 includes a printer 1, a scanner 110, and a document feeder 120. The scanner 110 is provided above the printer 1, and the document feeder 120 is provided above the scanner 110. The document feeder 120 feeds a document G via a reading position of the scanner 110. The scanner 110 is a flatbed image scanner that reads the document G and generates image data. The printer 1 forms an image on a sheet S based on the image data. Note that, although this embodiment shows an example in which the printer 1 forms an image using an electrophotographic method, the printer 1 may also be configured to form an image using an inkjet method.

[0016] The printer 1 includes a rectangular parallelepiped main body housing 3. At the bottom inside the main body housing 3 are a paper feed cassette 4 that stores sheets S, and a paper feed roller 5 that feeds sheets S from the paper feed cassette 4 to the right. Above the paper feed cassette 4 is an imaging device 6 that forms a toner image using an electrophotographic method, and above and to the right of the imaging device 6 is a fixing device 7 that fixes the toner image to the sheet S. Above the fixing device 7 are an ejection roller 8 that ejects the sheet S with the fixed toner image, and an ejection tray 9 on which the ejected sheet S is stacked.

[0017] Inside the main body housing 3, there is provided a conveyance path 10 that runs from the paper feed roller 5 through the image forming device 6 and the fixing device 7 to the discharge roller 8. The conveyance path 10 is mainly formed of plate-like members that face each other with a gap therebetween to allow the sheet S to pass through, and conveyance rollers 17 that sandwich and convey the sheet S are provided at multiple locations in the conveyance direction Y. A registration roller 18 is provided upstream of the image forming device 6 in the conveyance direction Y. To the right of the fixing device 7, there is provided a reversing conveyance path 10R that branches off from the conveyance path 10 downstream of the fixing device 7 in the conveyance direction Y and merges with the conveyance path 10 upstream of the registration roller 18 in the conveyance direction Y.

[0018] The control unit 2 includes a calculation unit and a storage unit (not shown). The calculation unit is, for example, a CPU (Central Processing Unit). The storage unit includes storage media such as a ROM (Read Only Memory), a RAM (Random Access Memory), and an EEPROM (Electrically Erasable Programmable Read Only Memory). The calculation unit performs various processes by reading and executing control programs stored in the storage unit. Note that the control unit 2 may be realized by an integrated circuit only, without using software.

[0019] A display operation unit (not shown) is provided on the front side of the scanner 110. The display operation unit includes a display panel, a touch panel superimposed on the display surface of the display panel, and a keypad adjacent to the display panel (not shown). The control unit 2 displays screens showing operation menus and statuses of the printer 1 and scanner 110 on the display panel, and controls each part of the printer 1 and scanner 110 in response to operations detected by the touch panel and keypad.

[0020] The basic image formation operation of the printer 1 is as follows: When a print job for single-sided printing is input to the printer 1 from the display operation unit or an external computer, the paper feed rollers 5 feed the sheet S from the paper feed cassette 4 to the transport path 10, the registration rollers 18, which have stopped rotating, correct any skew in the sheet S, and the registration rollers 18 feed the sheet S to the image creating device 6 at a predetermined timing. The image creating device 6 forms a toner image on the sheet S using an electrophotographic method. Next, the fixing device 7 fuses the toner image onto the sheet S while clamping and transporting the sheet S, and the discharge rollers 8 discharge the sheet S onto the discharge tray 9. In the case of double-sided printing, the sheet S with the toner image fixed on its first side is sent into the transport path 10 via the reverse transport path 10R, where the toner image is transferred to the second side.

[0021] [scanner] The scanner 110 comprises a first carriage 81 equipped with a light source and a reflecting mirror, a second carriage 82 equipped with two reflecting mirrors, a lens 83 that focuses the light, an image sensor 84 that converts the focused light into image data, and a contact glass 85 on which the original G is placed.

[0022] The basic document reading operation of the scanner 110 is as follows: When a user places a document G on the top surface of the contact glass 85 and gives a reading command to the scanner 110, the first carriage 81 moves to the right at a speed V, and in conjunction with this, the second carriage 82 moves to the right at a speed V / 2. During this time, the light source irradiates light onto the document G, and the light reflected by the document G is reflected by the reflecting mirrors of the first carriage 81 and the second carriage 82 and directed to the lens 83, where it is imaged on the imaging element 84 and converted into an image signal. The image signal is output to the control unit 2 of the printer 1 and converted into image data.

[0023] [Document transport device] Next, the document transport device 120 will be described. FIG. 2 is a perspective view showing the exterior of the document transport device 120. FIG. 3 is a perspective view showing the support member 23 and its surrounding area. FIG. 4 is a front view schematically showing the paper feed mechanism 31 and the transport mechanism 32. FIGS. 5 and 6 are front views schematically showing the transport mechanism 32 and the first lifting mechanism 33. Of these, FIG. 5 shows the state where the paper feed tray 44 is located at the upper limit position, and FIG. 6 shows the state where the paper feed tray 44 is located at the lower limit position. FIG. 7 is a rear view schematically showing the second lifting mechanism 34 and the drive unit 78. FIG. 8 is an enlarged view of the main parts of FIG. 7.

[0024] The document transport device 120 includes a paper feed tray 44 on which documents G are loaded, a discharge tray 43 provided below the paper feed tray 44, a feed roller 51 that feeds documents G one by one from the paper feed tray 44, a first lifting mechanism 33 that supports both ends of the documents G in the width direction intersecting the transport direction Z of the documents G in the paper feed tray 44 and raises and lowers the paper feed tray 44 so that the top surface of the documents G contacts the feed roller 51, a transport mechanism 32 that transports the documents G fed by the feed roller 51 to the discharge tray 43 via a reading position, a support member 23 that supports the paper feed tray 44 upstream of the first lifting mechanism 33 in the transport direction Z, and a second lifting mechanism 34 that raises and lowers the support member 23 in synchronization with the paper feed tray 44.

[0025] The document transport device 120 (see FIG. 2) has a flat, generally rectangular bottom 40 and a first wall 41 and a second wall 42 that face each other in the front-to-rear direction (the width direction intersecting with the transport direction Z of the document G). The rear edge of the bottom 40 is hinged to the rear of the contact glass 85 of the scanner 110. The bottom 40 also functions as a pressure plate that presses down the document G on the contact glass 85. The first wall 41 is provided from the left end of the front edge of the bottom 40 to the center. The second wall 42 is provided across the entire rear edge of the bottom 40. The cover 46 covers the upper and left sides of the space between the first wall 41 and the second wall 42. The lower left end of the cover 46 is hinged to the left end of the bottom 40.

[0026] [Paper Tray] The paper feed tray 44 is provided to the right of the center in the left-right direction of the document transport device 120 and in front of the second wall portion 42. The paper feed tray 44 is a plate-shaped member that is inclined so that the left side is lower. A pair of cursors 45 that align the front and rear ends of the document G are provided on the top surface of the paper feed tray 44.

[0027] [Output tray] The discharge tray 43 is provided below the paper feed tray 44. The discharge tray 43 is integral with the bottom portion 40. An inclined surface is provided in the center of the left-right direction of the discharge tray 43, with the left side being lower.

[0028] [Paper feed mechanism] The paper feed mechanism 31 (see FIG. 4) is provided in the space between the first wall portion 41 and the second wall portion 42. The paper feed mechanism 31 has a box-shaped holder 53 that is open at the bottom. Inside the holder 53, a feed roller 51, a driven roller 55, a drive roller 52, and an endless belt 56 are arranged with their axial direction aligned in the front-to-rear direction. The driven roller 55 is provided to the left of the feed roller 51. The drive roller 52 is provided to the left of the driven roller 55. The endless belt 56 is wound around the drive roller 52 and the driven roller 55. An auxiliary roller 57, whose axial direction is aligned in the front-to-rear direction, is pressed against the underside of the lower part of the endless belt 56.

[0029] The front and rear ends of the drive shaft 54 ​​of the drive roller 52 are supported by the first wall portion 41 and the second wall portion 42, and are connected to a drive unit (not shown) including a motor and a reduction gear. The holder 53 is supported by the drive shaft 54 ​​and can swing around the drive shaft 54. The driving force of the drive shaft 54 ​​is transmitted to the feed roller 51 by a transmission mechanism (not shown), such as a gear train or an endless belt.

[0030] The sensor 58 detects whether the paper feed tray 44 is positioned at a height that allows the document G to be fed. The sensor 58 is a transmission or reflection type optical sensor, and is provided on the inner surface of the cover portion 46. A light shielding plate 59 that protrudes upward or to the side is provided on the upper portion of the holder 53.

[0031] [First lifting mechanism] The first lifting mechanism 33 (see FIGS. 5 to 8) is provided on the front surface of the first wall portion 41 and the rear surface of the second wall portion 42. The drive pulley 71 and the driven pulley 72 (see FIGS. 7 and 8) are provided above and below the center of the rear surface of the second wall portion 42, respectively. The driven pulley 73 is provided at a height between the drive pulley 71 and the driven pulley 72 and to the left of the drive pulley 71 and the driven pulley 73. The guide pulley 76 is provided above and to the left of the driven pulley 72 and to the right of the driven pulley 73. The endless belt 70 is wound around the drive pulley 71, the driven pulleys 72 and 73, and the guide pulley 76. The drive unit 78 includes a motor 78M, a worm gear 78W, an idler gear 78i, and a drive gear 71G. The drive gear 71G is coupled to the shaft of the drive pulley 71.

[0032] The driven pulleys 91, 92, 93 and the guide pulley 96 (see FIG. 5) are provided on the front surface of the first wall portion 41 at positions facing the drive pulley 71, the driven pulleys 72, 73 and the guide pulley 76, respectively. The endless belt 90 is wound around the driven pulleys 91, 92, 93 and the guide pulley 96. The driven pulley 93 and the driven pulley 73 are connected to a common shaft.

[0033] The sliding portion 74 (see FIG. 8) is provided at the left end of the rear edge of the paper feed tray 44. The second wall portion 42 is provided with a first slit 421 whose longitudinal direction is in the up-down direction. The first slit 421 is provided at a position corresponding to the left end of the rear edge of the paper feed tray 44. The sliding portion 74 passes through the first slit 421 and is coupled to a portion of the endless belt 70 between the drive pulley 71 and the driven pulley 72.

[0034] A lift guide 75 is provided on the rear surface of the second wall 42. The lift guide 75 is a rail-shaped member with its longitudinal direction extending in the vertical direction. The sliding part 74 is slidable in the vertical direction along the lift guide 75.

[0035] The sliding portion 94 (see FIG. 5) is provided at the left end of the front edge of the paper feed tray 44. The sliding portion 94 is coupled to the endless belt 90 at a portion between the driven pulley 91 and the driven pulley 92.

[0036] An elevation guide portion 95 is provided on the front surface of the first wall portion 41. The elevation guide portion 95 is a rail-shaped member whose longitudinal direction is the up-down direction. The sliding portion 94 is slidable in the up-down direction along the elevation guide portion 95.

[0037] The basic operation of the first lifting mechanism 33 is as follows: The driving force generated by the motor 78M is transmitted to the drive gear 71G via the worm gear 78W and the idler gear 78i. The rotation of the drive pulley 71 together with the drive gear 71G causes the endless belt 70 to rotate, which in turn causes the driven pulleys 72 and 73 to rotate. The rotation of the driven pulley 93 together with the driven pulley 73 causes the endless belt 90 to rotate in synchronization with the endless belt 70. Because the paper feed tray 44 is connected to the endless belts 70 and 90 via the sliding portions 74 and 94, the forward and reverse rotation of the motor 78M causes the paper feed tray 44 to move up and down.

[0038] The control unit 2 causes the first lifting mechanism 33 to raise the paper feed tray 44 on which the document G is stacked. When the top surface of the document G is pressed against the feed roller 51, the holder 53 swings upward. When the holder 53 swings upward by a predetermined amount, the light shielding plate 59 blocks the light from the sensor 58. At this time, an appropriate load acts between the top surface of the document G and the feed roller 51, allowing the document G to be fed out by the feed roller 51.

[0039] [Transport mechanism] The transport mechanism 32 (see FIG. 4) includes a transport path 61 extending from the paper feed mechanism 31 to the opening 40A, a transport path 64 extending from the opening 40A to a discharge roller 69, and a plurality of transport rollers 62 disposed on the transport paths 61 and 64. The opening 40A is an example of a reading position where the scanner 110 reads the document G. The opening 40A is a slit with its longitudinal direction extending in the front-to-rear direction, provided in an area of ​​the bottom 40 facing the first carriage 81 (see FIG. 1) positioned at the home position. The transport paths 61 and 64 are primarily formed of plate-like members facing each other with a gap therebetween that allows the document G to pass through. At the reading position, an opening 61A corresponding to the opening 40A is provided in the plate-like member below the transport path 61, and the underside of the document G being transported is exposed through the openings 40A and 61A.

[0040] The transport roller 62 includes a drive roller and a driven roller. A driven pulley 62P (see FIG. 5) is coupled to the shaft of the drive roller. The drive pulley 63P is connected to a drive unit (not shown) including a motor and a reduction gear. The endless belt 60 is wound around the drive pulley 63P, multiple driven pulleys 62P, and a guide pulley 65. When the drive pulley 63P is driven, the multiple driven pulleys 62P rotate synchronously as the endless belt 60 rotates, and therefore the multiple transport rollers 62 also rotate synchronously.

[0041] [Supporting member] The support member 23 (FIGS. 2, 3, 5 to 8) supports the paper feed tray 44 upstream of the first lifting mechanism 33 in the transport direction Z of the originals G. Specifically, the support member 23 is provided in front of the second wall portion 42 (see FIGS. 2 and 3), and supports the rear end of the paper feed tray 44 in the width direction. The user faces the front of the image forming apparatus 100 to load originals G onto the paper feed tray 44, remove originals G from the discharge tray 43, operate the display operation unit, etc. The rear end of the paper feed tray 44 in the width direction is the rear end of the paper feed tray 44 as seen by the user, i.e., the rear end of the paper feed tray 44.

[0042] The support member 23 supports a portion of the rear end of the paper feed tray 44 that is slightly to the left of the right end. The underside of the paper feed tray 44 is inclined so that the left side is lower. A contact portion 44C that protrudes downward is provided on the underside of the paper feed tray 44 at a position slightly to the left of the right end of the rear end. The underside of the contact portion 44C is formed approximately horizontally. The support member 23 is shaped like a quadrangular pillar and has an approximately horizontal upper surface. The upper surface of the support member 23 contacts the underside of the contact portion 44C of the paper feed tray 44.

[0043] [Second lifting mechanism] The second lifting mechanism 34 is provided on the rear surface of the second wall portion 42 (see FIGS. 7 and 8). The second lifting mechanism 34 is, for example, a rack and pinion. The second wall portion 42 has a second slit 422 with its longitudinal direction extending in the up-down direction formed in a position corresponding to the support member 23 (see FIGS. 2, 3, 7 and 8). The rack 21 with its longitudinal direction extending in the up-down direction is provided behind the second slit 422. Teeth are formed on the left surface of the rack 21, and the pinion 24 is provided to the left of the rack 21.

[0044] Rack guide portions 22 that guide the rack 21 are provided above and below the second slit 422. The rack guide portions 22 restrict horizontal movement of the rack 21 and guide vertical movement of the rack 21. The rack 21 and the support member 23 face each other with the second slit 422 in between. A rack coupling portion 21C that protrudes forward is provided at the front of the rack 21 (see FIG. 3). The rack coupling portion 21C passes through the second slit 422 and is coupled to the support member 23.

[0045] The distributor 26 (see FIGS. 7 and 8) distributes the driving force generated by the driver 78 to the second lifting mechanism 34. Specifically, the drive pulley 26D is provided on the shaft of the driven pulley 72. The driven pulley 26N is provided on the shaft of the pinion 24. A guide pulley 26G is provided to the right of the drive pulley 26D and to the left of the pinion 24. An endless belt 26B is wound around the drive pulley 26D, the driven pulley 26N, and the guide pulley 26G.

[0046] The operation of the document transport device 120 is as follows: In Fig. 8, when the endless belt 70 is driven clockwise, the sliding portion 74 rises, and the paper feed tray 44 rises. At this time, the pinion 24 is also driven clockwise via the endless belt 26B, and the support member 23 rises together with the rack 21.

[0047] On the other hand, when the endless belt 70 is driven counterclockwise, the sliding portion 74 descends, and the sheet feed tray 44 descends. At this time, the pinion 24 is also driven counterclockwise via the endless belt 26B, and the support member 23 descends together with the rack 21.

[0048] In either case, the upper surface of the support member 23 contacts the lower surface of the paper feed tray 44, so the load acting on the paper feed tray 44 (gravity acting on the stacked documents G) is distributed to the first lifting mechanism 33 and the second lifting mechanism 34. As a result, changes in the posture and deformation of the paper feed tray 44 can be suppressed compared to when the load is supported by only the first lifting mechanism 33.

[0049] The document transport device 120 according to the present embodiment described above includes a paper feed tray 44 on which documents G are stacked, a discharge tray 43 provided below the paper feed tray 44, a feed roller 51 that feeds documents G one by one from the paper feed tray 44, a first lifting mechanism 33 that supports both ends of the documents G in the width direction intersecting the transport direction Z of the documents G in the paper feed tray 44 and lifts and lowers the paper feed tray 44 so that the top surface of the documents G contacts the feed roller 51, a transport mechanism 32 that transports the documents G fed by the feed roller 51 to the discharge tray 43 via a reading position, a support member 23 that supports the paper feed tray 44 upstream of the first lifting mechanism 33 in the transport direction Z, and a second lifting mechanism 34 that lifts and lowers the support member 23 in synchronization with the paper feed tray 44. This configuration can suppress changes in posture and deformation of the paper feed tray 44 when documents G are stacked thereon.

[0050] Furthermore, according to the document transport device 120 of this embodiment, the support member 23 supports the rear end in the width direction of the paper feed tray 44. This configuration prevents the support member 23 from interfering with the work of the operator.

[0051] Furthermore, according to the document transport device 120 of this embodiment, the support member 23 is in contact with the lower surface of the paper feed tray 44. With this configuration, the paper feed tray 44 can be supported with a simple configuration.

[0052] Furthermore, the document transport device 120 according to this embodiment includes a drive unit 78 that drives the first lifting mechanism 33, and a distributor 26 that distributes the drive force generated by the drive unit 78 to the second lifting mechanism 34. With this configuration, the second lifting mechanism 34 can be driven without providing a drive unit 78 in the second lifting mechanism 34 separately from the first lifting mechanism 33.

[0053] Furthermore, according to the document transport device 120 of this embodiment, the second lifting mechanism 34 includes the pinion 24 that rotates by the driving force distributed from the distribution unit 26, and the rack 21 that is provided with the vertical direction as its longitudinal direction and that meshes with the pinion 24, and the support member 23 is coupled to the rack 21. This configuration allows the second lifting mechanism 34 to have a highly rigid structure.

[0054] The above embodiment may be modified as follows.

[0055] In the above embodiment, an example is shown in which the support member 23 supports the rear end of the paper feed tray 44 in the width direction, but a support member 23 may be provided that supports the front end in addition to the rear end of the paper feed tray 44 in the width direction.

[0056] In the above embodiment, an example has been shown in which the support member 23 is in contact with the underside of the paper feed tray 44, but the support member 23 may be connected to the paper feed tray 44. In that case, it is desirable that the support member 23 be connected by a pin so that no bending moment is generated in the paper feed tray 44.

[0057] In the above embodiment, an example in which the distribution unit 26 is provided has been shown, but instead of the distribution unit 26, a drive unit 78 that drives the second lifting mechanism 34 may be provided.

[0058] In the above embodiment, an example was shown in which the second lifting mechanism 34 is a rack and pinion, but the second lifting mechanism 34 may be a cam, a ball screw, or the like. [Explanation of symbols]

[0059] 120 Document transport device 21 racks 23 Support member 24 Pinion 26 Distribution section 32 Transport mechanism 33 First lifting mechanism 34 Second lifting mechanism 43 Output tray 44 Paper tray 51 Feed roller 78 Drive Unit

Claims

1. a paper feed tray on which documents are loaded; an ejection tray provided below the paper feed tray; a feed roller that feeds the originals one by one from the paper feed tray in a predetermined transport direction; a first lifting mechanism that supports a rear side and a front side of the paper feed tray in a width direction intersecting the conveyance direction of the document, and lifts and lowers the paper feed tray so that an upper surface of the document contacts the feed roller; a conveying mechanism that conveys the document fed by the feed roller to the discharge tray via a reading position; a support member that supports the rear end of the paper feed tray upstream of the first lifting mechanism in the conveyance direction; a second lifting mechanism that lifts and lowers the support member in synchronization with the paper feed tray, the first lifting mechanism includes an upper first pulley and a lower second pulley arranged vertically near a downstream end of the paper feed tray in the conveying direction on the rear side and the front side, a first endless belt wound around the first pulley and the second pulley, and a drive unit that transmits a drive force to one of the first pulley and the second pulley, The document transport device is characterized in that the second lifting mechanism comprises a third pulley that is arranged coaxially with the second pulley at the rear and rotates synchronously with it, a fourth pulley that is arranged upstream of the third pulley in the transport direction, and a second endless belt that is wound around the third pulley and the fourth pulley.

2. 2. The document transport device according to claim 1, wherein the support member is in contact with a lower surface of the paper feed tray.

3. The second lifting mechanism is a pinion that rotates in synchronization with the rotation of the fourth pulley; a rack that is provided with its longitudinal direction in the up-down direction and that meshes with the pinion, 3. The document transport device according to claim 1, wherein the support member is connected to the rack.

Images