IMAGE FORMING APPARATUS, AND SHEET FEEDING DEVICE

Abstract

An image forming apparatus includes an image forming section that forms an image on a recording material, and a feeder that feeds the recording material to the image forming section, wherein the feeder includes a recording material accommodating unit that accommodates recording materials, a suction device that sucks air, forming members that are provided with an opening formed close to the recording materials accommodated in the recording material accommodating unit, and form a negative-pressure space, which has negative pressure due to suction by the suction device, together with the recording material facing the opening, partition members that include edge portions formed close to the opening, are formed so as to extend from the edge portions toward the inside of the negative-pressure space, and partition the negative-pressure space into two or more spaces, and feeding members that feed the recording material pulled toward the forming members when the negative-pressure space has negative pressure.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2012-155053 filed Jul. 10, 2012.

BACKGROUND

Technical Field

[0002] The present invention relates to an image forming apparatus, and a sheet feeding device.

SUMMARY

[0003] According to an aspect of the invention, there is provided an image forming apparatus including: an image forming section that forms an image on a recording material; and a feeder that feeds the recording material to the image forming section, wherein the feeder includes a recording material accommodating unit that accommodates recording materials, a suction device that sucks air, forming members that are provided with an opening formed close to the recording materials accommodated in the recording material accommodating unit, and form a negative-pressure space, which has negative pressure due to suction performed by the suction device, together with the recording material positioned at a position facing the opening, partition members that include edge portions formed close to the opening, are formed so as to extend from the edge portions toward the inside of the negative-pressure space, and partition the negative-pressure space into two or more spaces, and feeding members that feed the recording material pulled toward the forming members when the negative-pressure space has negative pressure.

BRIEF DESCRIPTION OF THE DRAWINGS

[0004] Exemplary embodiments of the present invention will be described in detail based on the following figures, wherein:

[0005] FIG. 1 is a schematic view showing the structure of an image forming apparatus according to an exemplary embodiment of the invention;

[0006] FIG. 2 is a view illustrating a sheet feeding device;

[0007] FIGS. 3A, 3B, and 3C are views illustrating the operation of the sheet feeding device;

[0008] FIG. 4 is a perspective view showing a sheet moving mechanism when the sheet moving mechanism is seen from below and from the upstream side in a sheet transport direction;

[0009] FIG. 5A to 5D are views showing the internal state of the sheet moving mechanism when a sheet is sucked;

[0010] FIGS. 6A and 6B are views showing another example of the structure of the sheet moving mechanism;

[0011] FIGS. 7A and 7B are views showing another example of the structure of the sheet moving mechanism;

[0012] FIGS. 8A and 8B are views showing another example of the structure of the sheet moving mechanism;

[0013] FIGS. 9A and 9B are views showing the sheet moving mechanism when the sheet moving mechanism is seen from the bottom of a box;

[0014] FIG. 10 is a view showing the sheet moving mechanism when the sheet moving mechanism is seen from a third side wall of the box; and

[0015] FIG. 11 is a view showing the sheet moving mechanism when the sheet moving mechanism is seen from the bottom portion.

DETAILED DESCRIPTION

[0016] An exemplary embodiment of the invention will be described in detail below with reference to the accompanying drawings.

[0017] FIG. 1 is a schematic view showing the structure of an image forming apparatus according to the exemplary embodiment of the invention.

[0018] An image forming apparatus 1 shown in FIG. 1 is an intermediate transfer type image forming apparatus that is called a tandem type image forming apparatus. The image forming apparatus 1 is provided with plural image forming units 1Y, 1M, 1C, and 1K that form toner images having respective color components by an electrophotographic method. Further, the image forming apparatus 1 is provided with primary transfer sections 10 that sequentially transfer (primarily transfer) the respective color toner images, which are formed by the respective image forming units 1Y, 1M, 1C, and 1K, to an intermediate transfer belt 15.

[0019] Furthermore, the image forming apparatus 1 is provided with a secondary transfer section 20 that collectively transfers (secondarily transfers) the superimposed toner images, which are transferred to the intermediate transfer belt 15, to a sheet. Moreover, the image forming apparatus 1 is provided with a fixing device 60 that fixes the secondarily transferred toner images to the sheet. In addition, the image forming apparatus 1 is provided with a controller 40 and an UI (User Interface) 70. The controller 40 controls the operation of each device (each section). The UI 70 is formed of a display panel or the like, receives information from a user, and displays information to the user. Further, the image forming apparatus 1 is provided with a sheet feeding device 54 that includes a sheet accommodating unit 53 as an example of a recording material accommodating unit.

[0020] Each of the image forming units 1Y, 1M, 1C, and 1K is provided with the following electrophotographic devices. First, a charger 12, which charges a photoreceptor drum 11, is provided around the photoreceptor drum 11 that rotates in the direction of arrow A. Further, a laser exposure unit 13 (an exposure beam shown in FIG. 1 is denoted by reference character Bm), which writes an electrostatic latent image on the photoreceptor drum 11, is provided. Furthermore, a developer unit 14, which changes the electrostatic latent image formed on the photoreceptor drum 11 into a visible image by using toners, is provided. Moreover, a primary transfer roll 16, which transfers each color toner image formed on the photoreceptor drum 11 to the intermediate transfer belt 15 at a primary transfer section 10, is provided. In addition, a drum cleaner 17, which removes the toner and the like remaining on the photoreceptor drum 11, is provided.

[0021] The intermediate transfer belt 15 is circularly driven at a predetermined speed in the direction of arrow B shown in FIG. 1. The primary transfer section 10 includes the primary transfer roll 16 that is disposed so as to face the photoreceptor drum 11 with the intermediate transfer belt 15 interposed therebetween. Further, the toner images formed on the respective photoreceptor drums 11 are sequentially and electrostatically attracted to the intermediate transfer belt 15, so that superimposed toner images are formed on the intermediate transfer belt 15.

[0022] The secondary transfer section 20 includes a back-up roll 25 and a secondary transfer roll 22 that is disposed on the toner image supporting surface of the intermediate transfer belt 15. Here, the secondary transfer roll 22 is disposed so as to be urged against the back-up roll 25 with the intermediate transfer belt 15 interposed therebetween. Furthermore, a secondary transfer bias is generated between the secondary transfer roll 22 and the back-up roll 25, so that the toner images are secondarily transferred to the sheet that is transported to the secondary transfer section 20.

[0023] Next, a basic image forming process of the image forming apparatus 1 according to this exemplary embodiment will be described. In the image forming apparatus 1 according to this exemplary embodiment, image data is output from an image reader (not shown) or the like. Further, the image data is subjected to image processing by an image processing device (not shown), are converted into gradation data of four color (Y, M, C, and K) materials, and are output to the laser exposure unit 13.

[0024] At the laser exposure units 13, the respective photoreceptor drums 11 of the image forming units 1Y, 1M, 1C, and 1K are irradiated with exposure beams Bm emitted from, for example, semiconductor lasers according to the input gradation data of color materials. The surfaces of the respective photoreceptor drums 11 are scanned and exposed by the laser exposure units 13 after being charged by the chargers 12. Accordingly, electrostatic latent images are formed on the photoreceptor drums 11. Furthermore, after toner images are formed on the photoreceptor drums 11 by the developer units 14, the toner images are transferred to the intermediate transfer belt 15 at the primary transfer sections 10 where the respective photoreceptor drums 11 come into contact with the intermediate transfer belt 15.

[0025] After the toner images are sequentially and primarily transferred to the surface of the intermediate transfer belt 15, the toner images are transported to the secondary transfer section 20 by the movement of the intermediate transfer belt 15. At the secondary transfer section 20, the secondary transfer roll 22 is pressed against the back-up roll 25 with the intermediate transfer belt 15 interposed therebetween. At this time, a sheet, which is transported from the sheet accommodating unit 53, is interposed between the intermediate transfer belt 15 and the secondary transfer roll 22.

[0026] Accordingly, the unfixed toner images, which are supported on the intermediate transfer belt 15, are collectively and electrostatically transferred to the sheet at the secondary transfer section 20. On the other hand, a sheet is transported to the secondary transfer section 20 from the sheet accommodating unit 53 (sheet feeding device 54) by the transport rolls 52 that are provided on a sheet transport path. After that, the sheet to which the toner images have been electrostatically transferred is transported to a transport belt 55, which is provided on the downstream side of the secondary transfer roll 22 in a sheet transport direction, after being separated from the intermediate transfer belt 15. Further, the transport belt 55 transports the sheet to the fixing device 60.

[0027] FIG. 2 is a view illustrating the sheet feeding device 54.

[0028] The sheet feeding device 54 of this exemplary embodiment functions as a part of a feeder that feeds a sheet as an example of a recording material to an image forming section including the image forming units 1Y, 1M, 1C, and 1K and the like. Here, the sheet feeding device 54 is provided with the sheet accommodating unit 53 in which plural sheets are loaded and accommodated. Moreover, the sheet feeding device 54 is provided with feed rolls 59. The feed rolls 59 are formed of a pair of roll-shaped members, and function as feeding members for feeding a sheet, which is pulled toward first to fourth plates 601 to 604 (of which the detail will be described below), toward the downstream side.

[0029] Further, the sheet feeding device 54 includes a sheet moving mechanism 58 that holds the uppermost sheet among the plural sheets accommodated in the sheet accommodating unit 53 by suction and moves this sheet to the feed rolls 59. Here, the sheet accommodating unit 53 includes a housing 531. Furthermore, the sheet accommodating unit 53 is provided with a bottom plate 532 that is received in the housing 531, supports the loaded plural sheets from below, and moves the sheets to the upper side in FIG. 2.

[0030] On the other hand, the sheet moving mechanism 58 includes a box 580 that is formed in the shape of a rectangular parallelepiped. Here, this box 580 includes a first side wall 581 that is disposed along the sheet transport direction, a second side wall 582 (not shown in FIG. 2) that is similarly disposed along the sheet transport direction and disposed on the side opposite to the first side wall 581, a third side wall 583 that is disposed on the downstream side in the sheet transport direction and disposed along a direction orthogonal to the sheet transport direction, and a fourth side wall 584 that is disposed on the upstream side in the sheet transport direction and disposed along the direction orthogonal to the sheet transport direction.

[0031] Further, the box 580 includes a box-like base part 586 that includes a rectangular opening at the lower portion thereof, and a bottom plate 587 that closes the opening of the base part 586. Furthermore, in this exemplary embodiment, suction ports (not shown in FIG. 2), which are used for the suction of a sheet, are formed in the bottom plate 587. Moreover, the sheet moving mechanism 58 includes first to fourth plates 601 to 604 that are formed in a rectangular shape and provided so as to be movable in the vertical direction of FIG. 2. Here, in this exemplary embodiment, these first to fourth plates 601 to 604 are supported by the box 580 as an example of a support member.

[0032] In detail, the first plate 601 is mounted on the first side wall 581 of the box 580 and disposed along the first side wall 581. Moreover, the first plate 601 is disposed from one end of the first side wall 581 in a longitudinal direction of the first side wall 581 to the other end of the first side wall 581 in the longitudinal direction. On the other hand, the second plate 602 (not shown) is also similar, and the second plate 602 is mounted on the second side wall 582 (not shown) of the box 580 and disposed along the second side wall 582. Further, the second plate 602 is disposed from one end of the second side wall 582 in a longitudinal direction of the second side wall 582 to the other end of the second side wall 582 in the longitudinal direction.

[0033] Furthermore, the third plate 603 is mounted on the third side wall 583 of the box 580 and disposed along the third side wall 583. Moreover, the third plate 603 is disposed from one end of the third side wall 583 in a longitudinal direction of the third side wall 583 to the other end of the third side wall 583 in the longitudinal direction. Further, likewise, the fourth plate 604 is mounted on the fourth side wall 584 of the box 580 and disposed along the fourth side wall 584. Furthermore, the fourth plate 604 is disposed from one end of the fourth side wall 584 in a longitudinal direction of the fourth side wall 584 to the other end of the fourth side wall 584 in the longitudinal direction. On the other hand, in this exemplary embodiment, the box 580 is provided on the side opposite to the sheet accommodating unit 53 with the first to fourth plates 601 to 604 interposed therebetween.

[0034] FIGS. 3A, 3B, and 3C are views illustrating the operation of the sheet feeding device 54.

[0035] When a sheet is fed by the sheet feeding device 54, first, as shown in FIG. 3A, the bottom plate 532 is moved upward and the uppermost sheet among the plural sheets placed on the bottom plate 532 comes into contact with the lower end portions of the first to fourth plates 601 to 604 of the sheet moving mechanism 58. Here, when the sheet comes into contact with the lower end portions of the first to fourth plates 601 to 604 as described above, a space (hereinafter, referred to as a "surrounded space") of which four sides and upper and lower sides are surrounded by the first to fourth plates 601 to 604, a sheet, and the bottom (bottom plate 587) of the box 580, is formed.

[0036] After that, in this exemplary embodiment, air present in the box 580 is sucked by a suction device 588 that includes a compressor, a fan, and the like and is discharged to the outside as shown in FIG. 3B. Accordingly, the air present in the surrounded space is discharged to the outside through the suction ports formed in the bottom of the box 580, so that the surrounded space is in a reduced pressure state. In other words, in this exemplary embodiment, a space, which is surrounded by the bottom of the box 580, a sheet, and the first to fourth plates 601 to 604, becomes a negative-pressure space, which is in a negative pressure state due to the suction that is performed by the suction device 588.

[0037] In more detail, in this exemplary embodiment, a space (a negative-pressure space having negative pressure) of which four sides are surrounded by the first to fourth plates 601 to 604 functioning as forming members is formed and a rectangular opening 680 (see FIGS. 2 and 4) is formed at a position, which is close to the sheet, in the space. Further, in this exemplary embodiment, the surrounded space is formed by a sheet that is positioned at a position facing the opening 680, the first to fourth plates 601 to 604, and the bottom of the box 580.

[0038] Furthermore, when air present in this surrounded space is discharged to the outside, the surrounded space is in a negative pressure state (a state where pressure is lower than atmospheric pressure). Accordingly, a sheet is pulled toward the box 580 (the first to fourth plates 601 to 604). Here, when the sheet is pulled toward the box 580, the first to fourth plates 601 to 604 are pressed by this sheet. Accordingly, the first to fourth plates 601 to 604 are moved toward the box 580.

[0039] Therefore, a sheet is attached to the bottom of the box 580 as shown in FIG. 3B. After that, in this exemplary embodiment, as shown in FIG. 3C, the box 580 is moved toward the feed rolls 59 by a moving mechanism, which is formed using existing technology such as a motor, so that a sheet is delivered to the feed rolls 59. On the other hand, in this exemplary embodiment, the pressure in the surrounded space returns to the atmospheric pressure when a sheet is delivered to the feed rolls 59.

[0040] FIG. 4 is a perspective view showing the sheet moving mechanism 58 when the sheet moving mechanism 58 is seen from below and from the upstream side in the sheet transport direction.

[0041] Although not described above, fifth and sixth plates 605 and 606 functioning as partition members, which partition the surrounded space into two or more spaces, are provided in addition to the first to fourth plates 601 to 604 in this exemplary embodiment.

[0042] Here, each of the fifth and sixth plates 605 and 606 includes an opening-side edge portion 690 formed close to the rectangular opening 680, and is formed so as to extend from the opening-side edge portion 690 toward the inside of the surrounded space. Further, the fifth and sixth plates 605 and 606 are disposed between the first and second plates 601 and 602. Furthermore, the fifth and sixth plates 605 and 606 are disposed at positions that are different from each other in the direction orthogonal to the sheet transport direction. Moreover, the fifth and sixth plates 605 and 606 are disposed along the sheet transport direction.

[0043] Further, the fifth and sixth plates 605 and 606 are disposed from the position where the third plate 603 is provided to the position where the fourth side wall 604 is provided. Furthermore, in this exemplary embodiment, the fifth plate 605 is positioned close to the first plate 601 and the sixth plate 606 is positioned close to the second plate 602. Moreover, like the first to fourth plates 601 to 604, the fifth and sixth plates 605 and 606 are provided so as to be movable in the vertical direction of FIG. 4. Further, in this exemplary embodiment, the fifth and sixth plates 605 and 606 can be received in the box 580 and two slits (not shown) are formed on the bottom portion of the box 580 so that the fifth and sixth plates 605 and 606 are received in the box 580.

[0044] Here, when the fifth and sixth plates 605 and 606 are not provided and a sheet having a width smaller than a distance between the first and second plates 601 and 602 is accommodated in the sheet feeding device 54, a gap is formed between the sheet and the first plate 601 and between the sheet and the second plate 602. Further, air passes through this gap in this case, so that the suction of a sheet performed by the box 580 is difficult. For this reason, the fifth and sixth plates 605 and 606 are provided between the first and second plates 601 and 602 in this exemplary embodiment. In this case, the above-mentioned gap is not easily formed, so that the suction of a sheet is more reliably performed.

[0045] More specific description will be made with reference to FIGS. 5A to 5D (which are views showing the internal state of the sheet moving mechanism 58 when a sheet is sucked). On the other hand, FIGS. 5A and 5C are cross-sectional views taken along a plane 4A of FIG. 4 and are cross-sectional views of the sheet moving mechanism 58 when the sheet moving mechanism 58 is seen in the direction of arrow 4C (from the upstream side in the sheet transport direction). Further, FIGS. 5B and 5D are cross-sectional views taken along a plane 4B of FIG. 4 and are cross-sectional views of the sheet moving mechanism 58 when the sheet moving mechanism 58 is seen in the direction of arrow 4D. Furthermore, a state where a sheet is not yet sucked is shown in FIGS. 5A and 5B, and a state where a sheet has started to be sucked is shown in FIGS. 5C and 5D.

[0046] The above-mentioned surrounded space is formed by the fifth plate 605, the sixth plate 606, the bottom of the box 580, a sheet, the third plate 603, and the fourth plate 604 when the fifth and sixth plates 605 and 606 are provided as shown in FIGS. 5A and 5B. For this reason, when the sheet is sucked, the sheet is moved so as to be pulled toward the box 580 as shown in FIGS. 5C and 5D. Moreover, the third to sixth plates 603 to 606 are pressed by the moving sheet, so that the third to sixth plates 603 to 606 are moved toward the box 580. Accordingly, a sheet is sucked by the box 580 even though having a small size (width).

[0047] On the other hand, since the fifth and sixth plates 605 and 606 are provided as described above in this exemplary embodiment, a sheet having a small size is also able to be sucked. But, for example, the box 580 may also be made small (the size of the bottom portion of the box 580 may be reduced) so that a sheet having a small size is able to be sucked. On the other hand, if a sheet having a large size is sucked in this case, the end portion of the sheet is apt to hang down. Further, the delivery of a sheet to the feed rolls 59 (see FIG. 2) is apt to be unstable in this case.

[0048] Furthermore, if the box 580 is made small, a suction force for sucking a sheet is apt to be reduced. Moreover, in this case, it is difficult to suck a sheet that has a large size and is heavy.

[0049] For this reason, in this exemplary embodiment, the box 580 has been provided with the fifth and sixth plates 605 and 606 without being made small. In this case, not only a sheet having a large size but also a sheet having a small size is stably sucked.

[0050] FIGS. 6A and 6B are views showing another example of the structure of the sheet moving mechanism 58. On the other hand, FIGS. 6A and 6B are cross-sectional views taken along a plane 4B of FIG. 4 and are cross-sectional views of the sheet moving mechanism 58 when the sheet moving mechanism 58 is seen in the direction of arrow 4D.

[0051] Although not described above, in this exemplary embodiment, an opening 589 is formed at a portion, which is positioned close to the first side wall 581, of the ceiling of the box 580 as shown in, for example, FIG. 5c so that air present in the box 580 is discharged to the outside through the opening 589. In other words, when the fifth and sixth plates 605 and 606 are received in the box 580, the space of the box 580 is partitioned into three spaces as shown in FIG. 5c and three spaces, that is, a first partitioned space 5A, a second partitioned space 5B, and a third partitioned space 5C are formed. However, air present in any space is also discharged to the outside through the opening 589.

[0052] On the other hand, if the fifth and sixth plates 605 and 606 reach near the ceiling of the box 580 in this case, it is difficult to discharge air of the first and second partitioned spaces 5A and 5B to the outside. For this reason, in this exemplary embodiment, the fifth and sixth plates 605 and 606 are formed as shown in FIGS. 6A and 6B so that the air present in the first and second partitioned spaces 5A and 5B is easily discharged to the outside.

[0053] Here, in FIG. 6A, a recess (cut-out portion) 606B is formed at an upper edge 606A of the sixth plate 606 formed in a rectangular shape so that ventilation is improved. Further, in FIG. 6B, plural through holes 606C are formed at a portion of the sixth plate 606 received in the box 580 so that ventilation is improved. On the other hand, examples of the sixth plate 606 have been described with reference to FIGS. 6A and 6B, but the fifth plate 605 is also formed so as to have the same structure as the sixth plate 606.

[0054] On the other hand, a case where the opening 589 connected to the third partitioned space 5C of FIG. 5c is formed has been described as an example in this exemplary embodiment, but the opening 589 may be formed so as to be connected to the second partitioned space 5B. In other words, the opening 589 may be formed so as to be connected to a space, which is positioned in the middle, among three spaces that are arranged side by side.

[0055] If the opening 589 connected to the third partitioned space 5C is formed as shown in FIG. 5c, the degree of pressure reduction is reduced in order of the third partitioned space 5C, the second partitioned space 5B, and the first partitioned space 5A. In this case, pressure at one end of a sheet in the width direction is apt to be different from pressure at the other end of a sheet in the width direction at the time of suction. On the other hand, if the opening 589 is formed at the space, which is positioned in the middle, among three spaces that are arranged side by side, a difference between pressure when one end of the sheet in the width direction is sucked and pressure when the other end of the sheet in the width direction is sucked does not easily occur.

[0056] On the other hand, a case where three (odd number) spaces, that is, the first to third partitioned spaces 5A to 5C are formed has been described in this exemplary embodiment. However, when the partitioned spaces of which the number is an even number are formed, the opening 589 may be formed at one or both of two spaces that are positioned in the middle. On the other hand, when the opening 589 is formed at both of the two spaces, one opening 589 may be formed and the opening 589 may be formed so as to extend over the two spaces.

[0057] FIGS. 7A and 7B are views showing another example of the structure of the sheet moving mechanism 58. On the other hand, FIG. 7A is a view showing the state of the sheet moving mechanism 58 when a sheet having a large size is transported, and FIG. 7B is a view showing the state of the sheet moving mechanism 58 when a sheet having a small size is transported. Further, FIGS. 7A and 713 are cross-sectional views taken along the plane 4A of FIG. 4 and are cross-sectional views of the sheet moving mechanism 58 when the sheet moving mechanism 58 is seen in the direction of arrow 4C.

[0058] In the example of the structure shown in FIGS. 7A and 7B, the dimension of each of the fifth and sixth plates 605 and 606 (dimension in the transverse direction) is different from the dimension of each of the first and second plates 601 and 602 (dimension in the transverse direction) as shown in FIG. 7A. Furthermore, in this example of the structure, the length of a portion, which protrudes from the box 580, of each of the fifth and sixth plates 605 and 606 is smaller than the length of a portion, which protrudes from the box 580, of each of the first and second plates 601 and 602 as shown in FIG. 7A.

[0059] As a result of this structure, when a sheet having a large size is sucked, the first and second plates 601 and 602 come into contact with a sheet prior to the fifth and sixth plates 605 and 606 (the third and fourth plates 603 and 604 come into contact with a sheet prior to the fifth and sixth plates 605 and 606) as shown in FIG. 7A. Moreover, when a sheet having a small size is sucked, a sheet comes into contact with the fifth and sixth plates 605 and 606 at the positions that are closer to the box 580 than the positions of the ends of the first and second plates 601 and 602 as shown in FIG. 7B.

[0060] Further, since the dimension of each of the fifth and sixth plates 605 and 606 (dimension in the transverse direction) is smaller than the dimension of each of the first to fourth plates 601 to 604 (dimension in the transverse direction), a gap is formed between the ceiling of the box 580 (the inner surface of the box 580) and an edge portion of the fifth plate 605 (an edge portion positioned on the side opposite to the opening-side edge portion 690 (see FIG. 4)) and between the ceiling portion of the box 580 and an edge portion of the sixth plate 606 when the fifth and sixth plates 605 and 606 are received in the box 580. In this case, ventilation is ensured between the first partitioned space 5A (see FIG. 5c) and the second partitioned space 5B and between the second partitioned space 5B and the third partitioned space 5C.

[0061] FIGS. 8A and 8B are views showing another example of the structure of the sheet moving mechanism 58. On the other hand, FIG. 8A is a view showing a state where a sheet is not yet sucked, and FIG. 8B is a view showing a state where a sheet has started to be sucked. Further, FIGS. 8A and 8B are cross-sectional views taken along the plane 4A of FIG. 4 and are cross-sectional views of the sheet moving mechanism 58 when the sheet moving mechanism 58 is seen in the direction of arrow 4C.

[0062] In the example of the structure shown in FIGS. 8A and 8B, fifth and sixth plates 605 and 606 are provided as described above and as shown in FIG. 8A. On the other hand, in this example of the structure, an end portion of the fifth plate 605 close to the box 580 and an end portion of the sixth plate 606 close to the box 580 are fixed to the bottom of the box 580. Furthermore, each of the fifth and sixth plates 605 and 606 is adapted so as to be capable of pivoting on (rotating about) a portion thereof fixed to the box 580.

[0063] Moreover, the fifth plate 605 is disposed while being inclined so as to be close to the first plate 601 toward a sheet as shown in FIG. 8A. Further, the sixth plate 606 is disposed while being inclined so as to be close to the second plate 602 toward the sheet. Furthermore, a spring member (not shown) that urges the fifth plate 605 in a clockwise direction in FIG. 8A and a protrusion (not shown) that bumps against the urged fifth plate 605 and stops the fifth plate 605 at a position shown in FIG. 8A are provided in this example of the structure. Moreover, a spring member (not shown) that urges the sixth plate 606 in a counterclockwise direction in FIG. 8A and a protrusion (not shown) that bumps against the urged sixth plate 606 and stops the sixth plate 606 at a position shown in FIG. 8A are provided.

[0064] Here, when a sheet is sucked, the box 580 is moved to the upper side of the sheet as described above and the sheet comes into contact with the lower end portions of the fifth and sixth plates 605 and 606 as shown in FIG. 8A. Accordingly, the above-mentioned surrounded space is formed. After that, this surrounded space has negative pressure, so that the sheet is lifted up and the fifth and sixth plates 605 and 606 are pressed by the sheet due to this lift. Further, the fifth and sixth plates 605 and 606 pivot (rotate) so as to approach the box 580 due to this press. Accordingly, the sheet further approaches the box 580 and is attached to the bottom of the box 580 as shown in FIG. 8B.

[0065] On the other hand, since recesses 587A are formed on the bottom of the box 580 in this example of the structure, the fifth and sixth plates 605 and 606 are received in the recesses 587A when the sheet is sucked. Accordingly, since it is possible to prevent the fifth and sixth plates 605 and 606 from protruding from the bottom of the box 580, it is possible to prevent a gap from being formed between the bottom and the sheet. Therefore, the reduction of a suction force for sucking the sheet is suppressed.

[0066] FIGS. 9A and 9B are views showing the sheet moving mechanism 58 when the sheet moving mechanism 58 is seen from the bottom of the box 580.

[0067] As shown in FIG. 9A, plural suction ports 587B, which are formed so as to pass through a bottom portion (bottom plate 587) of the box 580 and used to suck air present in the surrounded space, are formed at the bottom of the box 580. Specifically, plural suction ports 587B are formed in each of a first area 9A positioned between the first and fifth plates 601 and 605, a second area 9B positioned between the fifth and sixth plates 605 and 606, and a third area 9C positioned between the sixth and second plates 606 and 602.

[0068] In other words, the plural suction ports 587B are formed in this exemplary embodiment so that air can be sucked from each of a space that is formed between the first and fifth plates 601 and 605 when the surrounded space is partitioned by the fifth plate 605, a space that is formed between the fifth and sixth plates 605 and 606 when the surrounded space is partitioned by the fifth and sixth plates 605 and 606, and a space that is formed between the second and sixth plates 602 and 606 when the surrounded space is partitioned by the sixth plate 606. On the other hand, thirty two suction ports 587B are formed in total in this exemplary embodiment. Further, the suction ports 587B are disposed in a lattice shape in this exemplary embodiment.

[0069] Furthermore, a first closing member 701 that is formed of a solid plate and closes the suction ports 587B formed in the first area 9A formed in a rectangular shape and a second closing member 702 that is formed of a solid plate likewise and closes the suction ports 587B formed in the third area 9C formed in a rectangular shape are provided as shown in FIG. 9A in this exemplary embodiment.

[0070] Here, in this exemplary embodiment, the first and second closing members 701 and 702 are mounted on the box 580 and the suction ports 587B formed in the first area 9A and the suction port 587B formed in the third area 9C are closed by a user when a sheet having a small size is transported. Accordingly, a suction force, when the sheet having a small size is transported, is further increased.

[0071] On the other hand, a case where the first and second closing members 701 and 702 are mounted manually by a user has been described here, but moving mechanisms for moving the first and second closing members 701 and 702 may be provided and the suction ports 587B may be closed automatically. Further, the first and second closing members 701 and 702 are not essential. It is possible to discharge air, which is present in the second area 9B, to the outside without the first and second closing members 701 and 702 although suction efficiency is lowered, and, it is possible to suck a sheet having a small size without the first and second closing members 701 and 702.

[0072] Furthermore, the first and second closing members 701 and 702 may be formed as shown in FIG. 9B. A base portion 703, which is formed so as to extend in the sheet transport direction, and plural protruding pieces 704, which are formed so as to protrude from the side of the base portion 703 and are interposed between adjacent suction ports 587B, are formed at each of the first and second closing members 701 and 702 in this example of the structure.

[0073] In the case of this example of the structure, each of the protruding pieces 704 is positioned between the suction ports 587B adjacent to each other and opens the suction ports 587B when a sheet having a large size is transported. Further, when a sheet having a small size is transported, the first and second closing members 701 and 702 slide so that the protruding pieces 704 are positioned at the positions facing the suction ports 587B. Accordingly, the suction ports 587B are closed.

[0074] Another example of the structure of the sheet moving mechanism 58 will be further described.

[0075] FIG. 10 is a view showing the sheet moving mechanism 58 when the sheet moving mechanism 58 is seen from the third side wall 583 of the box 580. In other words, FIG. 10 is a view showing the sheet moving mechanism 58 when the sheet moving mechanism 58 is seen from the downstream side in the sheet transport direction.

[0076] In this example of the structure, as shown in FIG. 10, the lower edge portion of the bottom plate 587 (the bottom of the box 580) is not linearly formed and the middle portion of the lower edge portion of the bottom plate 587 in the longitudinal direction is formed so as to be recessed. Here, in this case, when a sheet is sucked by the box 580, the sheet is deformed so as to follow the lower edge portion and a middle portion of the sheet in the width direction of the sheet (a middle portion of a sheet in the direction orthogonal to the sheet transport direction) protrudes in the thickness direction of the sheet. In other words, the sheet is bent. Accordingly, the bending stiffness of the sheet is increased in this example of the structure, so that the sheet is more stably delivered to the feed rolls 59 (see FIG. 2).

[0077] On the other hand, there is a concern that a gap is formed between the third plate 603 and the sheet and a suction force is reduced when the sheet is bent as described above. For this reason, the third plate 603 is divided into two plates 603A and 603B in this exemplary embodiment. In this case, even though the sheet is bent, the lower end portion of the third plate 603 easily follows the sheet. Accordingly, a gap is not easily formed between the third plate 603 and the sheet.

[0078] On the other hand, the two plates 603A and 603B are formed so that the right end portion of the plate 603A in FIG. 10 and the left end portion of the plate 603B in FIG. 10 overlap each other. Further, protrusions 96 formed on the third side wall 583 are fitted into slots 95 formed at both ends of the plates 603A and 603B, so that the two plates 603A and 603B are supported by the third side wall 583. Furthermore, a gap between the slot 95 and the protrusion 96 is set to be large in this example of the structure. For this reason, in this example of the structure, each of the two plates 603A and 603B is adapted so that the other end of each of the two plates 603A and 603B as a free end can rotate about one end of each of the two plates 603A and 603B. Accordingly, each of the two plates 603A and 603B can be inclined, so that the lower end portion of the third plate 603 is apt to follow a sheet.

[0079] On the other hand, a case where the third plate 603 is divided into the two plates has been described in this example of the structure, but the third plate 603 may be divided into three or more plates. Moreover, a case where the third plate 603 is divided has been described here as an example, but the first plate 601, the second plate 602, and the fourth to sixth plates 604 to 606 may also be divided likewise.

[0080] On the other hand, a case where the fifth and sixth plates 605 and 606 are provided has been described above. However, for example, elastic pieces, which are formed in a rectangular shape and elastically deformable, may be mounted instead of the fifth and sixth plates 605 and 606. In this case, when a sheet is sucked, the elastic pieces are curved (bent). Accordingly, the sheet becomes close to the bottom of the box 580. Further, when a state returns to a state where there is no sheet, each of the elastic pieces extends so as to be separated from the bottom of the box 580. Furthermore, the fifth and sixth plates 605 and 606 may not be provided and, for example, cloth or the like may hang down from the bottom of the box 580.

[0081] Moreover, a case where the fifth and sixth plates 605 and 606 are disposed along the sheet transport direction has been described above, but the fifth and sixth plates 605 and 606 may be disposed along the direction orthogonal to the sheet transport direction. Further, when two plates such as the fifth and sixth plates 605 and 606 are provided, one plate may be disposed along the sheet transport direction and the other plate may be disposed along the direction orthogonal to the sheet transport direction. Furthermore, two plates, that is, the fifth and sixth plates 605 and 606 have been provided in this exemplary embodiment. However, one plate may be provided and three or more plates may be provided.

[0082] Moreover, as shown in FIG. 11 (which is a view showing the sheet moving mechanism 58 when the sheet moving mechanism 58 is seen from the bottom portion), four plates 607 to 610, which are disposed in a rectangular shape, may be provided within the first to fourth plates 601 to 604 instead of the two plates, that is, the fifth and sixth plates 605 and 606 and a sheet having a small size may be sucked using the four plates 607 to 610.

[0083] That is, since the first to fourth plates 601 to 604 are used when a sheet having a large size is sucked and the third to sixth plates 603 to 606 are used when a sheet having a small size is sucked in the structure shown in FIG. 2 and the like, the third and fourth plates 603 and 604 have been used for multi purposes. However, in the example of the structure shown in FIG. 11, plates are not used for multi purposes, and the first to fourth plates 601 to 604 are used when a sheet having a large size is sucked and the plates 607 to 610 are used when a sheet having a small size is sucked.

[0084] The foregoing description of the exemplary embodiments of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to understand the invention for various embodiments and with the various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents.

Claims

1. An image forming apparatus comprising: an image forming section that forms an image on a recording material; and a feeder that feeds the recording material to the image forming section, wherein the feeder includes a recording material accommodating unit that accommodates recording materials, a suction device that sucks air, forming members that are provided with an opening formed close to the recording materials accommodated in the recording material accommodating unit, and form a negative-pressure space, which has negative pressure due to suction performed by the suction device, together with the recording material positioned at a position facing the opening, partition members that include edge portions formed close to the opening, are formed so as to extend from the edge portions toward the inside of the negative-pressure space, and partition the negative-pressure space into two or more spaces, and feeding members that feed the recording material pulled toward the forming members when the negative-pressure space has negative pressure.

2. The image forming apparatus according to claim 1, further comprising: a support member, which is provided with suction ports formed close to the forming members, sucks air present in the negative-pressure space through the suction ports when air present in the support member is discharged by the suction device, and supports the forming members, provided on the side opposite to the recording material accommodating unit with the forming members interposed therebetween, wherein the forming members are supported by the support member, are provided so as to be movable toward the support member, and are moved toward the support member by being pressed by the recording material that is moved toward the support member as air present in the negative-pressure space is sucked by the support member, and the partition members are also supported by the support member, are provided so as to be movable toward the support member, and are moved toward the support member by being pressed by the recording material that is moved toward the support member as air present in the negative-pressure space is sucked by the support member.

3. The image forming apparatus according to claim 2, wherein the partition members are received in the support member when being moved toward the support member by being pressed by the recording material.

4. The image forming apparatus according to claim 3, wherein gaps are formed between an inner surface of the support member and opposite-side edge portions, which are positioned on the side opposite to the edge portions, of the partition members when the partition members are received in the support member.

5. The image forming apparatus according to claim 3, wherein the partition members are formed so as to extend from the edge portions toward the inside of the negative-pressure space, and are formed in the shape of a plate, and through holes, which pass through the partition members in the thickness direction of the partition member, are formed at portions, which are received in the support member, of the partition members.

6. The image forming apparatus according to claim 4, wherein the partition members are formed so as to extend from the edge portions toward the inside of the negative-pressure space, and are formed in the shape of a plate, and through holes, which pass through the partition members in the thickness direction of the partition member, are formed at portions, which are received in the support member, of the partition members.

7. A sheet feeding device comprising: a sheet accommodating unit that accommodates sheets; a suction device that sucks air; forming members that are provided with an opening formed close to the sheets accommodated in the sheet accommodating unit, and form a negative-pressure space, which has negative pressure due to suction performed by the suction device, together with the sheet positioned at a position facing the opening; partition members that includes edge portions formed close to the opening, are formed so as to extend from the edge portions toward the inside of the negative-pressure space, and partition the negative-pressure space into two or more spaces; and feeding members that feed the sheet pulled toward the forming members when the negative-pressure space has negative pressure.

8. The sheet feeding device according to claim 7, further comprising: a support member, which is provided with suction ports formed close to the forming members, sucks air present in the negative-pressure space through the suction ports when air present in the support member is discharged by the suction device, and supports the forming members, provided on the side opposite to the sheet accommodating unit with the forming members interposed therebetween, wherein the forming members are supported by the support member, are provided so as to be movable toward the support member, and are moved toward the support member by being pressed by the sheet that is moved toward the support member as air present in the negative-pressure space is sucked by the support member, and the partition members are supported by the support member, are provided so as to be rotatable about predetermined portions thereof, and are rotated so as to approach the support member by being pressed by the sheet that is moved toward the support member as air present in the negative-pressure space is sucked by the support member.

9. The sheet feeding device according to claim 8, wherein recesses in which the partition members rotated so as to approach the support member are received are formed on a surface, on which the partition members are mounted, of the support member.

10. The sheet feeding device according to claim 8, wherein a plurality of the suction ports of the support member are formed so that air is sucked from each of the two or more spaces partitioned by the partition members, and the sheet feeding device further comprises a closing member that closes the suction ports formed so as to correspond to any space of the two or more spaces.

11. The sheet feeding device according to claim 9, wherein a plurality of the suction ports of the support member are formed so that air is sucked from each of the two or more spaces partitioned by the partition members, and the sheet feeding device further comprises a closing member that closes the suction ports formed so as to correspond to any space of the two or more spaces.

Images