Sheet conveying device, image reading device, and image forming apparatus

Abstract

To improve workability when setting various sheets having different sizes in a width direction on a loading section.SOLUTION: A sheet conveying device of the present invention is provided with a pair of first side fences 51, which are respectively installed at both ends in a width direction of a loading section 50. In addition, a pair of second side fences 52, which can regulate a width direction position of a document D loaded on the loading section 50, are installed on a width direction center side relative to the pair of first side fences 51 so as to be movable in the width direction. A compression spring 54 is provided to force the second side fence 52 to move toward the side of the center in the width direction. Furthermore, a guide fence 53, having the inclination angle relative to the first side fence 51 variable in conjunction with the width direction movement of the second side fence 52, is installed so as to relay between an end portion on the upstream side in a transport direction of the second side fence 52 and a position on the first side fence 51 upstream of the end portion in the transport direction.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a sheet transport device that transports sheets such as documents and paper, an image reading device equipped with the same, and an image forming apparatus such as a copying machine, a printer, a facsimile machine, or a combination machine or printing machine thereof. [Background technology]

[0002] 2. Description of the Related Art Conventionally, in image forming apparatuses such as copiers, printers, and printing machines, sheet conveying devices that convey sheets such as documents and papers placed on a placement portion in a predetermined conveying direction have been widely known (see, for example, Patent Document 1).

[0003] On the other hand, Patent Document 1 discloses a technique for installing a foldable second paper guide on the paper feed tray in addition to a first paper guide that can slide in the width direction. When normal size paper is set on the paper feed tray, the first paper guide regulates the width direction position of the paper with the second paper guide in the folded position. On the other hand, when small size paper such as business card size is set on the paper feed tray, the second paper guide is in the raised position and the second paper guide regulates the width direction position of the paper. Summary of the Invention [Problem to be solved by the invention]

[0004] Conventional sheet transport devices have been inconvenient when a user places sheets of different width sizes on a sheet placement unit. In particular, the technology of Patent Document 1 had poor workability because the second paper guide had to be raised or lowered depending on the width size of the sheet to be set on the placement table (paper table). Also, when trying to set a sheet with a large width size while the second paper guide was raised, the sheet could collide with the second paper guide and be damaged.

[0005] The present invention has been made to solve the above-mentioned problems, and aims to provide a sheet conveying device, an image reading device, and an image forming device that provide good operability when setting various sheets of different width sizes on the loading section. [Means for solving the problem]

[0006] The sheet conveying device of the present invention is a sheet conveying device that conveys a sheet in a predetermined conveying direction, and includes a placement section on which a sheet is placed, a pair of first side fences respectively installed at both widthwise ends of the placement section, a pair of second side fences installed so as to be movable in the width direction on the widthwise central side of the pair of first side fences and capable of regulating the widthwise position of the sheet placed on the placement section, a biasing member that biases the second side fences to move towards the widthwise central side, and a guide fence installed to relay between an upstream end of the second side fence in the conveying direction and a position on the first side fence upstream of the end, and whose inclination angle with respect to the first side fence is variable in conjunction with the widthwise movement of the second side fence. Effect of the Invention

[0007] According to the present invention, it is possible to provide a sheet conveying device, an image reading device, and an image forming device that provide good operability when setting various sheets having different widthwise sizes on the loading section. [Brief description of the drawings]

[0008] [Figure 1] 1 is an overall configuration diagram showing an image forming apparatus according to a first embodiment of the present invention. [Diagram 2] FIG. 1 is a diagram illustrating a configuration of an image reading device. [Diagram 3] FIG. 2 is a top view showing the sheet conveying device. [Figure 4] 11 is a top view showing an operation when a small-sized original is set on the sheet conveying device. FIG. [Diagram 5]11 is a top view showing an operation when a large-sized original is set on the sheet transport device. FIG. [Figure 6] 11 is a top view showing a problem when a small-sized document is set in a sheet conveying device as a comparative example. FIG. [Figure 7] 13 is a front view illustrating an operation when the second side fence is released from a locked state by a stopper portion in the sheet conveying device of the first modified example. FIG. [Figure 8] 13 is a front view illustrating an operation when the second side fence is released from a locked state by the stopper portion in the sheet conveying device of the second modified example. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the embodiments of the present invention will be described in detail with reference to the drawings. In each drawing, the same or corresponding parts are denoted by the same reference numerals, and the duplicated description will be appropriately simplified or omitted.

[0010] First, the overall configuration and operation of an image forming apparatus will be described with reference to FIGS. In Fig. 1, reference numeral 1 denotes a copying machine serving as an image forming apparatus, and reference numeral 10 denotes an image reading device that optically reads image information of an original D. Referring to Fig. 2, the image reading device 10 is composed of a scanner unit 2 in which a first CIS 80 serving as an image reading unit is installed, a sheet conveying device 60 (automatic original conveying device), and the like. Also, reference numeral 3 denotes an exposure section (writing section) that irradiates exposure light L based on image information read by image reading device 10 onto photosensitive drum 5, reference numeral 4 denotes an image creating section that forms a toner image (image) on the surface of photosensitive drum 5, and reference numeral 7 denotes a transfer section (image forming section) that transfers the toner image formed on photosensitive drum 5 onto paper P (paper). Also, 12 and 13 indicate feeding sections capable of storing approximately 500 sheets of paper P as sheets, 14 indicates a large-capacity feeding section capable of storing a large volume of paper P, and 15 indicates a manual feed section in which paper P for manual feeding can be set. Also, reference numeral 17 denotes registration rollers (timing rollers) that transport the paper P toward the transfer unit 7, 20 denotes a fixing device that fixes the toner image (unfixed image) carried on the paper P, 21 denotes a fixing roller installed in the fixing device 20, and 22 denotes a pressure roller installed in the fixing device 20. Also, reference numeral 31 denotes a discharge tray on which the paper P discharged from the image forming apparatus main body 1 is stacked.

[0011] With reference to FIG. 1, the operation of the image forming apparatus main body 1 during normal image formation will be described. First, in the image reading device 10, the document D as a sheet is transported (fed) from the placement unit 50 (document table) and passes through the first CIS 80 (a contact image sensor) as an image reading unit. At this time, the first CIS 80 optically reads the image (image information) formed on the surface of the document D passing through that position. The optical image information read by the first CIS 80 is converted into an electrical signal and then transmitted to the exposure unit 3 (writing unit). The exposure unit 3 then emits exposure light L, such as a laser beam, based on the image information of the electrical signal toward the surface of the photoconductor drum 5 of the imaging unit 4.

[0012] Meanwhile, in the image creating unit 4, the photosensitive drum 5 rotates clockwise in the figure, and after going through a predetermined image creating process (charging process, exposure process, and development process), an image (toner image) corresponding to the image information is formed on the photosensitive drum 5. Thereafter, the image formed on the surface of the photosensitive drum 5 is transferred onto the paper P conveyed by the registration rollers 17 in a transfer section 7 serving as an image forming section.

[0013] On the other hand, the paper P transported to the transfer unit 7 (image forming unit) operates as follows. First, one of the multiple feed units 12-15 in the image forming apparatus 1 is automatically or manually selected (for example, the topmost feed unit 12 in the apparatus body 1 is selected). Then, the topmost sheet of paper P stored in the feed unit 12 is fed by the feed mechanism 30 (comprised of a feed roller, a pickup roller, a backup roller, etc.) and conveyed toward the conveying path. Thereafter, the paper P passes through the conveying path on which multiple conveying rollers are arranged, and reaches the position of the registration rollers 17.

[0014] The paper P that has reached the position of the registration rollers 17 is transported toward a transfer unit 7 (image forming unit) in time for alignment with the image formed on the photosensitive drum 5. After the transfer process, the paper P passes through the transfer section 7, and then reaches the fixing device 20 via a transport path. The paper P that has reached the fixing device 20 is fed between the fixing roller 21 and the pressure roller 22, and the toner image is fixed to the paper P by the heat from the fixing roller 21 and the pressure from both members 21 and 22 (the fixing process). After the fixing process, the paper P with the fixed toner image is sent out from between the fixing roller 21 and the pressure roller 22 (the fixing nip), and then discharged from the image forming apparatus main body 1 and stacked on the discharge tray 31 as an output image. In this way, a series of image forming processes is completed.

[0015] In the image forming apparatus 1 according to the present embodiment, a large-capacity feeder 14 is provided on the side of the apparatus body. When the large-capacity feeder 14 is selected as the feeder, the paper P set in the large-capacity feeder 14 is fed from the large-capacity feeder 14, and the image forming process is carried out in the same manner as described above. Moreover, in the image forming apparatus 1 of the present embodiment, a manual feed section 15 is provided above the large-capacity feed section 14. When the manual feed section 15 is selected as the feed section, the paper P set in the manual feed section 15 is fed from the manual feed section 15, and the image forming process is carried out in the same manner as described above.

[0016] Next, the image reading device 10 will be described in detail with reference to FIG. 2, FIG. As shown in FIG. 2, the image reading device 10 is mainly composed of a scanner unit 2 and a sheet conveying device 60 (automatic document conveying device). The scanner unit 2 is composed of a first CIS 80 as an image reading unit, a first contact glass 81, a second contact glass 82, and the like. The sheet conveying device 60 is composed of a loading section 50 (original table), an original discharge section 62 (paper output tray), a pickup roller 63, a separation roller 64, a feed roller 65, multiple pairs of conveying rollers 66-72, a second CIS 90 as a second image reading section, a pressure plate 75, etc.

[0017] Here, the placement section 50 has an open space formed at the top, and is configured so that a user can place an original document D (a document in the form of a sheet) along the placement surface from the upstream side in the transport direction (configured so that a stack of multiple original documents D can be stacked). Further, the placement section 50 is configured such that a part of it can be raised and lowered so that the height position of the uppermost document D among the multiple documents D stacked thereon is always constant. In the present embodiment, the loading section 50 is provided with first and second side fences 51, 52, etc., which determine the position of the document D set on the loading section 50 in the width direction (perpendicular to the paper surface of Figures 1 and 2, and up and down in Figures 3 to 5); this will be described in detail later using Figures 3 to 5, etc.

[0018] The document discharge section 62 is disposed below the loading section 50, and is configured so that the document D (or the hard document CD) after the image has been read by the first CIS 80 or the second CIS 90 is discharged and loaded thereon (so that a stack of multiple documents is discharged and loaded thereon).

[0019] Further, on transport paths K1, K3 leading from the placement section 50 to the document discharge section 62, there are provided, in order from the upstream side, a pickup roller 63, an FRR type feeding mechanism (feed roller 65, separation roller 64), and a plurality of transport roller pairs 66-69, 72. These members 63-69, 72 function as a transport means that transports the document D placed on the placement section 50 toward the first CIS 80 and the second CIS 90, and then transports the document D toward the document discharge section 62.

[0020] The first CIS as an image reading section is a contact image sensor, and reads, via the first contact glass 81, image information of the document D that is conveyed by the conveying means and passes the position of the first contact glass 81. Moreover, the first contact glass 81 serving as the opposing plate is made of a light-transmitting material such as glass, and is placed on the transport path.

[0021] Hereinafter, an operation of reading only an image formed on one side of the document D set on the placement unit 50 (single-sided reading operation) in the image reading device 10 configured as above will be described. First, on the placement section 50, the original D (with an image formed on its upper surface) is loaded with its leading edge (leading edge in the transport direction) abutting against the reference wall. Then, when an instruction to read the image of the original D (copy instruction) is given by operating an operation panel (not shown), the originals D are transported by the pickup roller 63, starting from the top one on the placement section 50, toward the FRR type feeding mechanism (feed roller 65, separation roller 64). At this time, although there is a possibility that multiple sheets of the original D are transported, only the topmost original D is separated by separation in the FRR type and sent to the downstream transport path. Thereafter, the document D conveyed to the conveying path hits the nip portion of the pull-out roller 66, which is in a stopped state of rotation, and is subjected to skew correction (oblique feed correction). The skew-corrected document D is then conveyed downstream by the pull-out roller 66, which has started to rotate, and is conveyed to the position of the first CIS 80 (and the first contact glass 81) by the first and second conveying roller pairs 67 and 68. The image (image information) of the document D is then optically read by the first CIS 80. Thereafter, the document D from which the image has been read is discharged to the document discharge section 62 by a pair of transport rollers 69 and a pair of discharge rollers 72 . Such a series of document transport operations is repeated for all documents D loaded on the document loading section 50.

[0022] When reading an image formed on the back side of the document D in addition to the image formed on the front side, the document D, whose image on the front side has been read by the first CIS 80 (and the first contact glass 81), is then transported to the position of the second CIS 90 (which is a contact image sensor).Then, the image on the back side of the document D is optically read by the second CIS 90. Thereafter, the document D, from which the image on the back side has been read, is discharged to the document discharge section 62 by the pair of discharge rollers 72. The first and second CISs 80 and 90 extend in the width direction (perpendicular to the paper surface of Figures 1 to 4) and are configured to include at least the entire width of the maximum size original document D (so that the image of the maximum size original document D can be read across the width).

[0023] Here, the image reading device 10 in this embodiment is configured to read images even when the original D is fixed and not transported, rather than reading images while the original D is automatically transported by the sheet transport device 60. More specifically, a second contact glass 82 on which the document D can be placed in a substantially horizontal state is provided on the upper surface of the scanner unit 2 (the surface facing the bottom surface of the sheet transport device 60). The second contact glass 82 is made of a light-transmitting material such as glass, and is configured so that the height of its upper surface is substantially the same as the height of the upper surface of the scanner unit 2. Further, the sheet conveying device 60 is configured so that the upper part of the second contact glass 82 can be opened and closed, and a pressure plate 75 (which has appropriate elasticity, similar to known ones) is installed on the lower surface thereof.

[0024] When reading the image of the original D placed on the upper surface of the second contact glass 82 (when the original D is fixed and image reading is performed), the original D is sandwiched between the second contact glass 82 and the pressure plate 75. Specifically, the sheet transport device 60 in the closed state is opened, and the original D (with the front surface (image reading surface) facing down) is set on the upper surface of the exposed second contact glass 82. Thereafter, the sheet transport device 60 in the open state is closed so that the original D set on the second contact glass 82 is sandwiched between the pressure plate 75. Then, when an instruction to read an image of original D (copy instruction) is given by operating an operation panel (not shown), the first CIS 80 (or a dedicated CIS) moves to the right in FIG. 2 (the scanning direction) while in contact with the underside of the second contact glass 82, and the image of the entire surface of original D is optically read.

[0025] Hereinafter, the characteristic configuration and operation of the sheet conveying device 60 (image reading device 10, image forming device 1) in this embodiment will be described in detail with reference to FIGS. 3 to 5 etc. As previously described with reference to FIG. 2 and the like, the sheet transport device 60 transports the document D as a sheet in a predetermined transport direction. As shown in Figure 3, the sheet conveying device 60 in this embodiment is provided with a loading section 50 (original table), a pair of first side fences 51, a pair of second side fences 52, a pair of compression springs 54 as urging members, a pair of guide fences 53, and the like.

[0026] The placement section 50 is a portion on which the document D as a sheet is placed. The document D placed on the placement section 50 is transported by a pickup roller 63 in a transport direction (the direction of the black arrow in FIG. 3).

[0027] The pair of first side fences 51 are provided at both ends of the placement portion 50 in the width direction. The pair of first side fences 51 are fence-like members formed to stand vertically from the placement surface of the placement section 50 and extend in the transport direction. The pair of side fences 51 are fixed at positions spaced equal distances from a position (position indicated by a dashed line in FIG. 3) corresponding to the center position in the width direction of the document D (sheet) placed on the placement section 50 toward both ends in the width direction. The pair of first side fences 51 regulate (determine) the widthwise position of the document DL (see FIG. 5) of the maximum size that can be conveyed. That is, the pair of first side fences 51 sandwich both ends of the document D in the widthwise direction to determine its position. More specifically, when a pair of second side fences 52 (described later) are in close proximity to the pair of first side fences 51 (as shown in FIG. 5(B)), the widthwise position of the maximum size document DL (sheet) that can be transported is restricted. That is, the side fences 51 are linked and integrated with the guide fence 53 and the second side fence 52 so that the side fences 51 can move to a widthwise position of the maximum size document DL, and determine and restrict that position.

[0028] The pair of second side fences 52 are each a fence-like member that stands vertically from the placement surface of the placement section 50 and extends in the conveying direction. The pair of second side fences 52 are installed so as to be movable in the width direction on the widthwise central side (inside the pair of side fences 51) relative to the pair of first side fences 51, and are configured to be able to regulate the widthwise position of the document D (sheet) placed on the placement section 50.

[0029] Specifically, the pair of second side fences 52 sandwich both widthwise ends of the document D to determine its position. The second side fences 52 are formed so that their length in the transport direction is shorter than the length in the transport direction of the first side fence 51. The position of the end of the second side fence 52 on the downstream side in the transport direction (the left side in FIG. 3) is substantially the same as the position of the end of the first side fence 51 on the downstream side in the transport direction. Although not shown, the second side fence 52 is configured so that multiple bosses formed on its bottom fit into grooves formed to extend in the width direction on the mounting surface of the mounting section 50, allowing it to slide along the grooves. The second side fence 52 is configured so as to be movable within the range of the grooves (between the first side fence 51 and the position of the second side fence 52 shown in FIG. 3). The position of the second side fence 52 shown in FIGS. 3 and 4 is a position that determines the widthwise position of a document DS of the smallest size (eg, business card size) that can be conveyed.

[0030] The compression spring 54 functions as a biasing member that biases the second side fence 52 toward the center in the width direction. More specifically, one end of the compression spring 54 is connected to the inner wall surface of the first side fence 51, and the other end is connected to the outer wall surface of the second side fence 52. The biasing force of the compression spring 54 is set to a force that is not strong enough to bend the document D placed on the placement section 50, but is strong enough to move the second side fence 52 toward the center in the width direction. 3 as a reference position when no document D is set on the placement section 50. When a document D with a width size larger than the minimum size is set on the placement section 50, the second side fence 52 moves in the width direction according to the width size of the document D, and the width position of the document D is determined. In this embodiment, the compression spring 54 is used as the urging member, but the urging member is not limited to this, and a leaf spring, elastic rubber, or the like can also be used as the urging member.

[0031] The guide fence 53 is installed so as to relay between the end portion upstream in the conveying direction of the second side fence 52 (the position of the first connecting portion 53a) and a position on the first side fence 51 upstream in the conveying direction of the above-mentioned end portion (the position of the second connecting portion 53b). 5 and other figures, the inclination angle of the guide fence 53 relative to the first side fence 51 is varied in conjunction with the movement of the second side fence 52 in the width direction.

[0032] In detail, the guide fence 53 is a fence-like member that stands vertically from the loading surface of the loading section 50 and is formed so that its inner wall surface is connected to the inner wall surface of the first side fence 51 and the inner wall surface of the second side fence 52. The second side fence 52 and the guide fence 53 are connected by a first connecting portion 53a. This first connecting portion 53a is a hinge mechanism or the like, and is configured to rotate the guide fence 53 relative to the second side fence 52. The first side fence 51 and the guide fence 53 are connected by a second connecting portion 53b. This second connecting portion 53b is configured to be movable in the conveying direction (the left-right direction in FIGS. 3 and 4) along a guide portion formed on the first side fence 51.

[0033] Hereinafter, an example of the operation (operation) for setting the document DS having the smallest width size on the placement unit 50 will be described with reference to FIG. First, the user, while holding the smallest-sized document DS, pushes the document DS from the right side (upstream side in the transport direction) to the left side (downstream side in the transport direction) in FIG. 4. At this time, even if the document DS is pushed in with the corner of the leading edge positioned between the first side fence 51 and the second side fence 52 as shown in FIG. 4(A), the corner of the document DS will come into contact with the guide fence 53. Then, as shown in FIG. 4(B), the document DS moves in the direction of the diagonal arrow while the corner of the document DS follows the inclined surface of the guide fence 53, and is guided between the pair of second side fences 52. Then, the document DS is pushed in in this state and is finally inserted between the pair of second side fences 52, and the position of the document DS in the width direction is determined.

[0034] 6 as a comparative example, in which no guide fence 53 is provided, if the document DS is pushed in with the leading edge corner positioned between the first side fence 51 and the second side fence 52, the leading edge of the document DS will hit the second side fence 52 and be damaged. To avoid such a problem, the task of setting the document DS so that it fits between the pair of second side fences 52 is a difficult task that requires great care.

[0035] Hereinafter, the operation (operation) of setting the document DL having the maximum width size on the placement unit 50 will be described with reference to FIG. First, the user, holding the maximum-sized document DL, pushes the document DL from the right side (upstream side in the conveying direction) to the left side (downstream side in the conveying direction) in FIG. 5. At this time, as shown in FIG. 5(A), the corner of the leading edge of the document DL comes into contact with the guide fence 53 (located close to the first side fence 51). Then, while being pushed by the document DL, the guide fence 53 changes its inclination angle so as to follow the first side fence 51. Then, with such displacement of the guide fence 53, as shown in FIG. 5(B), the second side fence 52 moves toward the end in the width direction, and the document DL is guided between them. Finally, the document DL is inserted between the pair of the first and second side fences 51 and 52, and the position of the document DL in the width direction is determined. When an original document D smaller than the maximum size and larger than the minimum size is set on the placement section 50, the second side fence 52 moves to match the widthwise size of the original document D through an operation basically similar to that shown in Figure 5, and the widthwise position of the original document D is determined at that position.

[0036] In this manner, the sheet conveying device 60 in this embodiment is provided with the first side fence 51 for large size sheets and the second side fence 52 for small size sheets, as well as the compression spring 54 for biasing the second side fence 52 and the guide fence 53 for relaying the first side fence 51 and the second side fence 52. Therefore, it is not necessary to raise or lower the second side fence 52 according to the width direction size of the document D set on the placement section 50, and the document D does not collide with the second side fence 52 as described above with reference to FIG. 6, and the workability when setting the document D on the placement section 50 is improved. In other words, regardless of the width direction size of the document D set on the placement section 50, the workability when setting the document D on the placement section 50 is improved for all documents D of various width direction sizes.

[0037] <Variation 1> As shown in FIG. 7, the sheet conveying device 60 in the first modification is provided with a stopper portion 57 serving as a locking mechanism, and an operating portion 93 (cam mechanism) serving as an unlocking mechanism. 7 is a front view of the placement unit 50 as viewed from the downstream side in the conveying direction, similar to FIG. 8 which will be used in the description of the second modified example below. As shown in Fig. 7(A), the stopper portion 57 functions as a locking mechanism for maintaining a locked state in which the second side fence 52 is close to the first side fence 51 against the bias of the compression spring 54 (biasing member). More specifically, the stopper portion 57 engages with the lower end portion of the second side fence 52 at a position below the mounting surface of the mounting portion 50, thereby restricting the movement of the second side fence 52 toward the center in the width direction due to the bias of the compression spring 54. Note that the stopper portion 57 is configured to be rotatable about a support shaft as the center, as shown in Figs. 7(B) and (C). On the other hand, the operating unit 93 is provided as a part of the cam mechanism and functions as an unlocking mechanism for manually releasing the locked state by the stopper unit 57 (locking mechanism). More specifically, the cam mechanism is configured to engage with the stopper unit 57 and rotate the stopper unit 57 around the support shaft. The operating unit 93 is configured to manually operate the cam mechanism. With this configuration, the user can manually operate the operating unit 93 to operate the cam mechanism, switching between a state in which the second side fence 52 is locked by the stopper portion 57 as shown in Figure 7(A) and a state in which the second side fence 52 is unlocked from the lock state by the stopper portion 57 as shown in Figure 7(B). Thus, for a user who rarely uses small-sized documents DS, the ease of setting a large-sized document DL for that user can be improved by maintaining the second side fence 52 in a locked state close to the first side fence 51 as shown in Fig. 7(A). When setting a small-sized document DS that is used infrequently on the placement section 50, the user operates the operation section 93 to release the locked state of the second side fence 52, and sets the small-sized document DS in the setting method as previously described with reference to Fig. 4 etc.

[0038] As shown in FIG. 7, the sheet conveying device 60 in the first modified example is provided with a pair of second guide fences 55 in addition to the above-mentioned guide fence 53 (first guide fence). The second guide fence 55 is installed so as to relay between the upper end portion of the second side fence 52 (the position of the first second connecting portion 55a) and a position on the first side fence 51 higher than the above-mentioned upper end portion (the position of the second second connecting portion 55b). The inclination angle of the second guide fence 55 with respect to the first side fence 51 is variable in conjunction with the movement of the second side fence 52 in the width direction. More specifically, the second guide fence 55 is a fence-like member formed such that its inner wall surface is connected to the inner wall surface of the first side fence 51 and the inner wall surface of the second side fence 52. The second guide fence 55 is a fence member having an inclined surface that widens in the conveying direction. The second side fence 52 and the second guide fence 55 are connected by a first second connecting portion 55a. This first second connecting portion 55a is a hinge mechanism or the like, and is configured to rotate the second guide fence 55 relative to the second side fence 52. The first side fence 51 and the second guide fence 55 are connected by a second second connecting portion 55b. The second second connecting portion 55b is configured to be movable in the up and down direction along a guide portion formed on the first side fence 51. With this configuration, as shown in FIG. 7C, when the user sets the document D (a document larger than the small size) from above to below on the placement section 50 with the second side fence 52 unlocked by the stopper section 57, the corners at both ends of the document D in the width direction first come into contact with the second guide fence 55. Then, the second guide fence 55 changes its inclination angle so as to approach the first side fence 51 while being pushed by the document D. Then, with such displacement of the second guide fence 55, the second side fence 52 moves toward the end in the width direction, and guides the document D between them. Finally, the document D is inserted between the pair of second side fences 52, and the position of the document D in the width direction is determined. Incidentally, when a small-sized original DS or a large-sized original DL is set from above, the original is set using the same operating principle as that previously explained using Figures 4, 5, etc., although there is a difference between the up-down direction and the transport direction. Therefore, regardless of the width direction size of the document D to be set on the placement section 50, the workability when setting the document D on the placement section 50 is improved.

[0039] <Variation 2> As shown in FIG. 8, a sheet conveying device 60 in the second modification is also provided with a stopper portion 57 as a locking mechanism and a second guide fence 55, similarly to the one shown in FIG. Unlike variant 1, variant 2 is provided with a motor 94 (cam mechanism) that functions as an unlocking mechanism, and a detection sensor 95 as detection means that can detect whether or not the stopper portion 57 (locking mechanism) is in a locked state. 8(A) to (C), motor 94 is provided as a part of a cam mechanism that automatically operates the cam mechanism, and functions as an unlocking mechanism for automatically releasing the locked state caused by stopper portion 57 (locking mechanism). More specifically, the cam mechanism is configured to engage with stopper portion 57 and rotate stopper portion 57 about a support shaft. Motor 94 is configured to be able to drive the cam mechanism. With this configuration, the user can drive the motor 94 by operating an operation panel (not shown) to switch between a state in which the second side fence 52 is locked by the stopper portion 57 as shown in Figure 8(A) and a state in which the second side fence 52 is unlocked by the stopper portion 57 as shown in Figure 8(B). As a result, similarly to what has been explained above in the first modification, it is possible to improve usability for users who rarely use small-sized documents DS. In the second modification, a detection sensor 95 such as a distance measuring sensor capable of optically detecting the distance from the stopper portion 57 is provided below the stopper portion 57 (which is a portion that is particularly subject to large displacement). This detection sensor 95 detects a state in which the stopper portion 57 has rotated to an upper position (locked position) as shown in Figures 8(A) and (C) and a state in which the stopper portion 57 has rotated to a lower position (unlocked position) as shown in Figure 8(B), while controlling the drive of the motor 94 to prevent switching failure between the locked state and the unlocked state.

[0040] As described above, the sheet conveying device 60 in this embodiment is a sheet conveying device that conveys a sheet in a predetermined conveying direction, and includes a placement section 50 on which a document D (sheet) is placed, and a pair of first side fences 51 that are respectively installed at both ends in the width direction of the placement section 50. A pair of second side fences 52 that can regulate the width direction position of the document D placed on the placement section 50 are installed on the side of the width direction center portion relative to the pair of first side fences 51 so as to be movable in the width direction. A compression spring 54 (urging member) that urges the second side fence 52 to move toward the width direction center portion is also provided. Furthermore, a guide fence 53 whose inclination angle with respect to the first side fence 51 is changed in conjunction with the width direction movement of the second side fence 52 is installed so as to relay between an end portion on the upstream side of the second side fence 52 in the conveying direction and a position on the first side fence 51 upstream of the end portion in the conveying direction. This improves the ease of operation when setting various documents D (sheets) having different widthwise sizes on the placement section 50.

[0041] In this embodiment, the present invention is applied to a sheet conveying device 60 (image reading device 10) installed in a monochrome image forming apparatus 1, but the present invention can naturally also be applied to a sheet conveying device (image reading device) installed in a color image forming apparatus. Furthermore, in this embodiment, the present invention is applied to a sheet conveying device 60 (image reading device 10) installed in an electrophotographic image forming apparatus 1, but the application of the present invention is not limited to this, and the present invention can also be applied to a sheet conveying device (image reading device) installed in other types of image forming apparatus (for example, an inkjet image forming apparatus, a stencil printing machine, etc.). In addition, in this embodiment, the present invention is applied to a sheet conveying device 60 that conveys a document D as a sheet, but the application of the present invention is not limited to this, and for example, the present invention can also be applied to feeding sections 12-15 that serve as sheet conveying devices that convey paper P as a sheet. Even in such cases, the same effects as those of this embodiment can be obtained.

[0042] It is clear that the present invention is not limited to the present embodiment, and that the present embodiment may be modified as appropriate within the scope of the technical concept of the present invention in addition to the modifications suggested in the present embodiment. Furthermore, the number, position, shape, etc. of the components are not limited to the present embodiment, and may be any number, position, shape, etc. suitable for implementing the present invention.

[0043] In this application, the term "sheet" is defined to include not only the original document D set in the sheet conveying device 60 of the image reading device 10, but also paper P placed in the feeding sections 12, 13, the large-capacity feeding section 14, or the manual feeding section 15. [Explanation of symbols]

[0044] 1 Image forming apparatus (image forming apparatus main body), 2 Scanner unit, 10 Image reader, 50 placement portion, 51 first side fence (first regulating member), 52 second side fence (second regulating member), 53 Guide fence (guide member), 53a, 53b connection part, 54 compression spring (biasing member), 55 Second guide fence, 55a, 55b second connection part, 57 Stopper part (locking mechanism), 60 sheet conveying device, 93 Operation unit (unlock mechanism), 94 Motor (unlock mechanism), 95 Detection sensor (detection means), D, DS, DL manuscript (sheet).

[0045] The present invention can also be embodied in the following combinations of Supplementary Notes 1 to 8. (Appendix 1) A sheet conveying device that conveys a sheet in a predetermined conveying direction, a placement section on which a sheet is placed; A pair of first side fences are provided at both ends of the placement section in the width direction, a pair of second side fences that are installed on the width direction center side of the pair of first side fences so as to be movable in the width direction and that can regulate the width direction position of the sheet placed on the placement section; a biasing member that biases the second side fence toward a width direction center portion; a guide fence provided to relay an end portion of the second side fence on an upstream side in the conveying direction and a position on the first side fence upstream of the end portion in the conveying direction, the guide fence having an inclination angle with respect to the first side fence varied in response to movement of the second side fence in a width direction; A sheet conveying device comprising: (Appendix 2) The sheet conveying device described in Appendix 1, characterized in that the pair of first side fences are fixed at positions spaced equal distances from each other toward both widthwise ends from a position corresponding to the widthwise center position of the sheet placed on the stacking section. (Appendix 3) The sheet conveying device described in Appendix 1 or Appendix 2, characterized in that when the pair of second side fences are in close proximity to the pair of first side fences, the widthwise position of a sheet of the maximum size that can be conveyed is regulated. (Appendix 4) a locking mechanism for maintaining a locked state in which the second side fence is close to the first side fence against the biasing force of the biasing member; an unlocking mechanism for releasing the locked state by the locking mechanism; 4. The sheet conveying device according to claim 1, further comprising: (Appendix 5) The sheet conveying device according to claim 4, wherein the lock release mechanism is a mechanism for manually or automatically releasing the locked state set by the lock mechanism. (Appendix 6) The sheet conveying device according to claim 4 or 5, further comprising a detection unit capable of detecting whether or not the locking mechanism is in the locked state. (Appendix 7) A sheet conveying device according to any one of Supplementary Note 1 to Supplementary Note 6, an image reading unit that reads an image formed on a surface of the sheet conveyed by the sheet conveying device; An image reading device comprising: (Appendix 8) 7. An image forming apparatus comprising the sheet conveying device according to claim 1. [Prior art documents] [Patent documents]

[0046] [Patent Document 1] Japanese Patent Application Laid-Open No. 10-291695

Claims

1. A sheet conveying device that conveys a sheet in a predetermined conveying direction, a placement section on which a sheet is placed; A pair of first side fences are provided at both ends of the placement section in the width direction, a pair of second side fences that are disposed on the width direction center side of the pair of first side fences so as to be movable in the width direction and that can regulate the width direction position of the sheet placed on the placement section; a biasing member that biases the second side fence toward a width direction center portion; a guide fence provided to relay an end portion of the second side fence on an upstream side in the conveying direction and a position on the first side fence upstream of the end portion in the conveying direction, the guide fence having an inclination angle with respect to the first side fence varied in response to movement of the second side fence in a width direction; A sheet conveying device comprising:

2. 2. The sheet conveying device according to claim 1, wherein the pair of first side fences are fixed at positions spaced apart from each other by an equal distance from a position corresponding to a widthwise center position of the sheet placed on the stacking section toward both widthwise ends.

3. 3. The sheet conveying device according to claim 1, wherein when the pair of second side fences are adjacent to the pair of first side fences, a widthwise position of a sheet of a maximum size that can be conveyed is restricted.

4. a locking mechanism for maintaining a locked state in which the second side fence is close to the first side fence against the biasing force of the biasing member; an unlocking mechanism for releasing the locked state by the locking mechanism; 3. The sheet conveying device according to claim 1, further comprising:

5. 5. The sheet transport device according to claim 4, wherein the lock release mechanism manually or automatically releases the locked state set by the lock mechanism.

6. 5. The sheet conveying apparatus according to claim 4, further comprising a detection means for detecting whether or not the locking mechanism is in the locked state.

7. The sheet conveying device according to claim 1 or 2, an image reading unit that reads an image formed on a surface of the sheet conveyed by the sheet conveying device; An image reading device comprising:

8. 3. An image forming apparatus comprising the sheet conveying device according to claim 1.

Images