Feeding device and image forming apparatus

Abstract

To prevent feeding failure of a sheet from occurring regardless of a direction of curl in the sheet.SOLUTION: A feeding device is arranged with a first guide section 75 that can be in contact with a lower surface of a manually fed sheet P, and a second guide section 76 that can be in contact with an upper surface of the sheet P. The plurality of restricting rollers 81 to 86 are arranged so that an opposed distance to a placing surface 71a gradually decreases as a position in a conveyance direction becomes more downstream. Conveyance rollers 90-92, guide members 97, 98, and brush roller pair 95 are installed downstream of the plurality of restricting rollers 81 to 86 in the transport direction. A pair of side fences 72 and 73 are installed on the placing surface 71a so as to extend from the most upstream side to the position of the most downstream side restriction roller 86. A blower 74 is installed to eject air upwardly through a plurality of holes 71a1 formed in the placing surface 71a.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a feeding device for feeding sheets such as paper, and an image forming apparatus such as a copying machine, a printer, a facsimile machine, or a multifunction machine or a printing machine including the same.

Background Art

[0002] Conventionally, in an image forming apparatus such as a copying machine, a printer, or a printing machine, as a feeding device for feeding sheets such as paper, a manual feeding device that feeds a sheet manually set on a manual tray exposed on the side of the image forming apparatus or the like is known (see, for example, Patent Document 1).

[0003] On the other hand, Patent Document 1 discloses a technique of installing a curl removing mechanism in a manual feeding device in order to correct the upward curl of a sheet placed on a manual tray.

Summary of the Invention

Problems to be Solved by the Invention

[0004] Conventional feeding devices can correct the curl of a sheet in a certain direction on the placement portion (tray), but cannot correct the curl in other directions. Therefore, the sheet is fed in a curled state, resulting in feeding failures such as jams (sheet jams).

[0005] The present invention has been made to solve the above problems, and an object thereof is to provide a feeding device and an image forming apparatus in which feeding failures of a sheet are less likely to occur regardless of the direction of curl of the sheet.

Means for Solving the Problems

[0006] The feeding device in this invention is a feeding device for feeding a sheet in a predetermined transport direction, comprising: a mounting section having a mounting surface on which the sheet can be placed; a first guide section positioned at a height distance from the mounting surface and located at the upstream end of the transport direction, and capable of contacting the lower surface of the manually inserted sheet; a second guide section positioned at a height distance from the mounting surface and located downstream of the first guide section in the transport direction, and capable of contacting the upper surface of the sheet; and a third guide section arranged parallel to the second guide section downstream of the transport direction, and positioned such that the distance to the mounting surface gradually decreases as the position in the transport direction moves downstream, and capable of contacting the upper surface of the sheet. The device comprises a plurality of limiting rollers, a conveying roller installed downstream of the plurality of limiting rollers in the conveying direction to convey the sheet placed on the aforementioned surface in the conveying direction, a pair of brush rollers installed downstream of the aforementioned surface and the conveying rollers in the conveying direction to convey the sheet conveyed by the conveying rollers in the conveying direction, a guide member that guides the sheet conveyed by the conveying rollers toward the nip of the pair of brush rollers, a pair of side fences that limit the position of the sheet in the width direction perpendicular to the conveying direction, and a blower that blows air upward from a plurality of holes formed in the aforementioned surface. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a feeding device and an image forming apparatus that are less prone to sheet feeding defects, regardless of the direction of curl in the sheet. [Brief explanation of the drawing]

[0008] [Figure 1] This is an overall configuration diagram showing an image forming apparatus according to an embodiment of the present invention. [Figure 2] This is a diagram showing the configuration of the feeding device. [Figure 3] This is a top view showing the feeding device. [Figure 4] This diagram shows the operation of the sheet in the feeding device. [Figure 5]This figure shows the operation of the sheet following Figure 4. [Modes for carrying out the invention]

[0009] Hereinafter, embodiments for carrying out this 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 redundant explanations will be simplified or omitted as appropriate.

[0010] First, Figure 1 will explain the overall configuration and operation of the image forming apparatus 1. In Figure 1, 1 is a copier as an image forming apparatus, 2 is a document reading unit that optically reads image information from the original document D, and 3 is an exposure unit that irradiates exposure light L onto the photoreceptor drum 5 based on the image information read by the document reading unit 2. Furthermore, 4 is an imaging unit that forms a toner image (image) on the photoreceptor drum 5, 7 is a transfer roller that contacts the photoreceptor drum 5 via a transfer transport belt 8 to form a transfer nip, 8 is a transfer transport belt that transfers and transports the toner image formed on the photoreceptor drum 5 to the sheet P, and 10 is a document transport unit (automatic document transport device) that transports the set document D to the document reading unit 2. Furthermore, 12 and 13 represent a paper feed cassette (feeding device) in which sheets P such as paper are stored, and 17 represents a register roller (timing roller) that transports the sheet P toward the transfer nip. Furthermore, 20 is a fixing device that fixes the toner image (unfixed image) supported on the sheet P, 21 is a fixing roller installed on the fixing device 20, 22 is a pressure roller installed on the fixing device 20, 31 is an output tray on which sheets P ejected from the main body of the device 1 are loaded, 70 is a feeding device (manual feed feeding device) that feeds manually fed sheets P, and 100 is an operation display panel on which operation buttons for displaying various information and performing operations on the device are displayed.

[0011] Referring to Figure 1, the operation of the image forming apparatus 1 during normal image forming will be explained. First, the original document D is transported (fed) from the document table in the direction of the arrow in the diagram by the transport rollers of the document transport unit 10 and passes over the document reading unit 2. At this time, the image information of the original document D passing over it is optically read by the document reading unit 2. The optical image information read by the document reading unit 2 is then converted into an electrical signal and transmitted to the exposure unit 3 (writing unit). The exposure unit 3 then emits exposure light L, such as laser light, based on the image information in the electrical signal, onto the photosensitive drum 5 of the image formation unit 4.

[0012] Meanwhile, in the image-forming unit 4, the photoreceptor drum 5 rotates clockwise as shown in Figure 1, and after a predetermined image-forming process (charging process, exposure process, and development process), an image (toner image) corresponding to the image information is formed on the photoreceptor drum 5. Subsequently, the image formed on the photoreceptor drum 5 is transferred to the sheet P, which is transported by the register roller 17, at the transfer nip (the position where the transfer roller 7 contacts the photoreceptor drum 5 via the transfer transport belt 8).

[0013] Meanwhile, the sheet P being transported to the transfer nip operates as follows: First, one of the multiple paper feed cassettes 12 and 13 of the image forming apparatus body 1 is automatically or manually selected (for example, the uppermost paper feed cassette 12 is selected). Then, the uppermost sheet P stored in the paper feed cassette 12 is fed by the paper feeding mechanism 52 (composed of a feed roller, pickup roller, backup roller, etc.) and transported towards the transport path. After that, the sheet P passes through the transport path, which is equipped with multiple transport rollers, and reaches the position of the register roller 17. Furthermore, if the manual feeding device 70 (manual feeding device) installed on the side of the main body 1 is selected, the sheet P placed by hand on the mounting section 71 (see Figure 2) of the feeding device 70 will be fed towards the transport path where the pair of feeding rollers 55 is installed, and then reach the position of the register roller 17.

[0014] Once the sheet P reaches the position of the register roller 17, it is transported toward the transfer nip in time to align with the image formed on the photoreceptor drum 5. After the transfer process, the sheet P passes through the transfer nip and is then transported by the transfer conveyor belt 8 to the fixing device 20. The sheet P that reaches the fixing device 20 is fed between the fixing roller 21 and the pressure roller 22, and the toner image is fixed by the heat received from the fixing roller 21 and the pressure received from both components 21 and 22 (this is the fixing process). The sheet P after the fixing process, with the toner image fixed, is fed out from between the fixing roller 21 and the pressure roller 22 (this is the fixing nip), and then discharged from the image forming apparatus body 1 and loaded onto the output tray 31 as the output image. Thus, the series of image formation processes is completed.

[0015] The feeding device 70 (manual feeding device), which is a characteristic feature of this embodiment, will be described in detail below. As shown in Figures 2 and 3, the feeding device 70 in this embodiment is a manual feeding device that feeds the sheet P in a predetermined transport direction (the feeding direction shown by the dashed arrow in Figure 2, which is the direction from right to left in Figure 3). The feeding device 70 consists of a mounting section 71 (tray), a pair of side fences 72 and 73, a first guide section 75, a second guide section 76, multiple limiting rollers 81 to 86, multiple transport rollers 90 to 92, guide members 97 and 98, a pair of brush rollers 95, a blower 74, and the like. In particular, in the feeding device 70, the components are arranged in the following order from the upstream side along the conveying direction: first guide section 75, second guide section 76, multiple limiting rollers 81-86, multiple conveying rollers 90-92, guide members 97, 98, and brush roller pair 95.

[0016] The placement part 71 has a placement surface 71a on which the sheet P can be placed. In particular, in the present embodiment, the placement surface 71a of the placement part 71 is a flat surface that slopes downward from the upstream side (the right side in FIGS. 2 and 3) to the downstream side (the left side in FIGS. 2 and 3) in the conveyance direction. Further, a plurality of hole parts 71a1 (see FIGS. 3 to 5) are formed in the placement surface 71a. Also, at the bottom of the placement part 71, a blower device 74 composed of a blower fan, a duct, etc. is installed. The blower fan of the blower device 74 is connected to the placement part 71 via a duct, and the outside air sucked by the blower fan is sent to the plurality of hole parts 71a1 via the duct. Then, by the blower device 74, air is jetted upward (in the direction of the white arrow in FIGS. 4 and 5.) from the plurality of hole parts 71a1 formed in the placement surface 71a.

[0017] The pair of side fences 72, 73 restrict the position in the width direction of the sheet P (the direction orthogonal to the conveyance direction, which is the direction perpendicular to the paper surface in FIG. 2, the vertical direction in FIG. 3, and the left-right direction in FIG. 4). That is, the side fences 72, 73 are respectively installed at both ends in the width direction so as to sandwich the sheet P, and are configured to be movable in the width direction in accordance with the size of the sheet P in the width direction by a manual movement mechanism (not shown). Also, in the present embodiment, the pair of side fences 72, 73 are formed so as to extend over the entire conveyance direction on the placement surface 71a.

[0018] The first guide part 75 is located at a position separated from the placement surface 71a in the height direction (the direction perpendicular to the placement surface 71a), and is arranged at the most upstream side (the right end side in FIGS. 2 and 3) in the conveyance direction. This first guide part 75 is a substantially plate-shaped member and is configured to be able to contact the lower surface of the sheet P inserted by hand. Specifically, as shown in FIGS. 2 and 4(A), the user (operator) inserts the gripped sheet P from the right side in FIG. 2 onto the first guide part 75 and inserts it toward the left side in FIG. 2 so as to straddle it.

[0019] The second guide section 76 is located at a position separated from the mounting surface 71a in the height direction (perpendicular to the mounting surface 71a) and is positioned downstream of the first guide section 75 in the transport direction (left side in Figures 2 and 3). This second guide portion 76 is a roughly plate-shaped member and is configured to be able to contact the upper surface of the sheet P inserted by hand from the upstream side. Specifically, as shown in Figures 2 and 4(B), the user inserts the grasped sheet P from the right side of Figure 2, towards the left side of Figure 2, so as to sandwich it between the first guide portion 75 and the second guide portion 76. In other words, the upper surface of the sheet P inserted towards the left side of Figure 2 so as to rest on the first guide portion 75 is guided by the second guide portion 76.

[0020] Multiple limiting rollers 81-86 are arranged in parallel on the downstream side in the conveying direction relative to the second guide section 76. In particular, in this embodiment, the six limiting rollers 81-86 are arranged with spacing in the conveying direction. Furthermore, the multiple limiting rollers 81 to 86 are arranged such that the distance between them and the mounting surface 71a (the distance perpendicular to the mounting surface 71a) gradually decreases as their position in the conveying direction moves downstream. Specifically, the distance between them and the mounting surface 71a decreases in the order of the uppermost limiting roller 81, the limiting roller 82 adjacent to it downstream, and the limiting rollers 83, 84, 85, and 86 further downstream. These limiting rollers 81-86 are configured to be able to contact the upper surface of the sheet P. Specifically, as shown in Figures 2 and 4(C), the sheet P, inserted from the right side of Figure 2 so as to be sandwiched between the first guide section 75 and the second guide section 76, is guided by the second guide section 76 and enters between the uppermost limiting roller 81 and the mounting surface 71a, and sequentially enters between the limiting rollers 81-86 so as to approach the mounting surface 71a along the transport direction. At this time, all of the limiting rollers 81-86 are rotated clockwise in Figure 2 by a drive mechanism (not shown), thereby improving the transportability (movability) of the sheet P. In this embodiment, the limiting rollers 81 to 86 are configured with multiple roller sections arranged side by side on a core shaft at intervals in the width direction. However, the configuration of the limiting rollers is not limited to this, and for example, a single roller section formed across the width direction on a core shaft can also be used.

[0021] The conveyor rollers 90-92 are installed downstream of the multiple limiting rollers 81-86 in the conveying direction. The conveyor rollers 90-92 then convey the sheet P placed on the mounting surface 71a in the conveying direction. Specifically, as shown in Figures 2 and 5(A), the conveyor rollers consist of a plurality of conveyor rollers 90-92 (in this embodiment, three conveyor rollers) arranged in parallel at intervals in the conveying direction, pressed against the mounting surface 71a (or with the distance between them set to approximately the thickness of the sheet). The plurality of conveyor rollers 90-92 are all driven to rotate clockwise in Figure 2 by a drive mechanism (not shown), conveying the sheet P on the mounting surface 71a to the left in Figure 2 at a constant speed. In this embodiment, the conveyor rollers 90 to 92 are configured with multiple roller sections arranged side-by-side on a core shaft at intervals in the width direction. However, the configuration of the conveyor rollers is not limited to this, and for example, a single roller section formed across the width direction on a core shaft can also be used.

[0022] The brush roller pair 95 is installed downstream in the conveying direction from the mounting surface 71a and the conveying rollers 90-92. The brush roller pair 95 then conveys the sheet P, which has been conveyed by the conveying rollers 90-92, toward the feed roller pair 55 in the conveying direction. Specifically, as shown in Figures 2, 3, and 5(B), the brush roller pair 95 is arranged vertically so that the two brush rollers form a nip (a low-pressure nip formed by the brush bristles). The brush rollers of the brush roller pair 95 have brush bristles (for example, made of Teflon, which has low triboelectric properties) wound around a metal core. Furthermore, the brush roller pair 95 is positioned away from the downstream end of the mounting section 71 (mounting surface 71a). Furthermore, the brush roller pair 95 is driven to rotate at high speed (higher than the linear speed of the conveying rollers 90-92) along the conveying direction by a drive mechanism (not shown) that does not affect the conveyance of the sheet P. Specifically, in Figure 2, the upper brush roller rotates clockwise, and the lower brush roller rotates counterclockwise. As a result, the sheet P is conveyed while being flattened and beaten by the brush roller pair 95, further correcting any curls.

[0023] Guide members 97 and 98 are roughly plate-shaped members that guide the sheet P, which has been conveyed by the conveyor rollers 90 to 92, toward the nip of the brush roller pair 95. Specifically, as shown in Figures 2 and 3, the guide member consists of a first guide member 97 facing the upper surface of the sheet P and a second guide member 98 facing the lower surface of the sheet P. The sheet P, conveyed by the conveyor rollers 90-92, is guided by the guide members 97 and 98, and its leading edge is fed into the nip of the brush roller pair 95.

[0024] By using the feeding device 70 configured in this way, regardless of the direction of curl in the sheet P, the curl can be corrected, making it less likely for the sheet P to be poorly fed. More specifically, as shown in Figures 4(C), 5(A), (B), etc., whether the sheet P is set with a concave curl in the width direction and upward, whether the sheet P is set with a concave curl in the transport direction and upward, whether the sheet P is set with a concave curl in the width direction and downward, or whether the sheet P is set with a concave curl in the transport direction and downward, the sheet P is transported downstream in the transport direction by multiple limiting rollers 81-86 so that it gradually comes into close contact with the mounting surface 71a. Therefore, regardless of the direction or size of the curl in the sheet P, the curl is corrected by the multiple limiting rollers 81-86, and the sheet P in a curl-free state is pressed against the mounting surface 71a by the transport rollers 90-92 while being transported, further enhancing the curl correction. Furthermore, since the sheet P that has been curl-corrected in this way is transported downstream with low nip pressure by the brush roller pair 95, problems such as curling occurring again due to nip pressure are reduced compared to when it is transported downstream with high nip pressure. Furthermore, the brush roller pair 95 rotates at a relatively high speed, and as it transports the sheet P while beating and stretching it, it can more actively correct the curl of the sheet P. Furthermore, as the sheet P moves on the mounting surface 71a, the air ejected by the blower 74 exerts an upward force, which reduces the likelihood of the sheet P getting caught on the mounting surface 71a. Furthermore, since the manually inserted sheet P is smoothly guided to the positions of the multiple limiting rollers 81-86 by the first and second guide sections 75 and 76, the ease of setting the sheet P into the feeding device 70 is improved.

[0025] Referring to Figures 3 and 4, etc., in this embodiment, the multiple holes 71a1 formed in the mounting portion 71 (mounting surface 71a) are arranged so that the ends are denser than the center in the width direction. More specifically, each of the multiple holes 71a1 is formed with a predetermined diameter that does not obstruct the transport of the sheet P (i.e., does not cause the sheet P to get caught). Furthermore, the number of holes 71a1 per unit area at both ends in the width direction is set to be greater than the number of holes 71a1 per unit area at the center in the width direction. As a result, the force (wind force) that lifts the sheet P as it moves on the mounting surface 71a is greater at both ends in the width direction compared to the center in the width direction. Therefore, even when a sheet P is transported that is curled in a concave shape downward (or convex shape upward) in the width direction, it becomes possible to lift both ends of the sheet P in the width direction with a strong force, thereby reducing the likelihood of the sheet P getting caught on the mounting surface 71a. Furthermore, it is preferable that holes 71a1 are not placed at both ends of the sheet P in the width direction in order to prevent the sheet P from getting caught on the holes 71a1. Furthermore, in this embodiment, the force (wind force) that lifts the sheet P is made greater at both ends in the width direction than at the center in the width direction by adjusting the number of holes 71a1 per unit area. However, as long as the force that lifts the sheet P is greater at both ends in the width direction than at the center in the width direction, the configuration is not limited to that of this embodiment, and for example, it is also possible to configure it so that the amount of air ejected at both ends in the width direction is greater than the amount of air ejected at the center in the width direction.

[0026] Furthermore, in this embodiment, as shown in Figure 3, the side fences 72 and 73 are formed such that the spacing between them in the width direction gradually decreases from the upstream side to the downstream side in the conveying direction, from the upstreammost side to the position of the uppermost limiting roller 81 among the multiple limiting rollers 81 to 86. In other words, as shown in Figure 3, the side fences 72 and 73 are provided with inclined portions 72a and 73a on the upstream side in the conveying direction (the right side in Figure 3) that are inclined with respect to the conveying direction. The inclined portion 72a of one side fence 72 and the inclined portion 73a of the other side fence 73 face each other and function as fence surfaces that can contact the side edge of the sheet P. The inclined portions 72a and 73a are formed to be inclined towards the center in the width direction from the upstream side (corresponding to the uppermost side of the side fences 72 and 73) to the downstream side (the position of the uppermost limiting roller 81 (the position on the near side)). In this way, by providing inclined sections 72a and 73a on the side fences 72 and 73, when the user inserts the sheet P held by the user from the right side of Figure 3 (when inserting by hand), even if the sheet P is skewed (inclined rather than straight with respect to the transport direction), the skew will be corrected as the widthwise spacing of the inclined sections 72a and 73a on both sides gradually decreases. Therefore, the user can insert the sheet P by hand with a certain degree of approximation without being too conscious of the skew of the sheet P (improving the ease of manual insertion).

[0027] Furthermore, in this embodiment, as shown in Figure 4(A), the side fences 72 and 73 are formed such that the spacing in the width direction (left-right direction in Figure 4(A)) is constant from the mounting surface 71a to a predetermined height position, and the spacing in the width direction gradually increases as the height position rises from that predetermined height position. Specifically, as shown in Figure 4(A), the side fences 72 and 73 are provided with vertical wall sections 72b and 73b on the side (downward) closest to the mounting surface 71a, which stand perpendicular to the mounting surface 71a. Above these vertical wall sections 72b and 73b, inclined wall sections 72c and 73c are provided, the spacing between them in the width direction gradually increases upward. More specifically, the relationship between the vertical wall sections 72b, 73b and the inclined wall sections 72c, 73c is maintained throughout the entire transport direction of the side fences 72, 73, as shown in Figures 4 and 5. Furthermore, the two vertical wall sections 72b, 73b are set so that their widthwise spacing approximately matches the widthwise size of the sheet P (see Figure 5(A)). As shown in Figure 5(A), the vertical wall sections 72b, 73b actually function to grip the sheet P in the area where the multiple transport rollers 90-92 are located. In this way, by providing vertical wall sections 72b, 73b and inclined wall sections 72c, 73c on the side fences 72, 73, in the range from the upstream side to the position of the transport rollers 90-92, the inclined wall sections 72c, 73c correct (correct) the widthwise misalignment (lateral resistance) of the sheet P as it moves downward by its own weight (or manually), so that the sheet P moves to the target position in the center. Then, in the range of the multiple transport rollers 90-92, the sheet P, with its widthwise misalignment (lateral resistance) corrected by the vertical wall sections 72b, 73b, is transported toward the brush roller pair 95.

[0028] In this embodiment, both the first guide section 75 and the second guide section 76 are divided and installed on a pair of side fences 72 and 73, respectively, and are not positioned in the center in the width direction. In other words, as shown in Figures 3, 4(A), and 4(B), the first guide section 75 and the second guide section 76 are not provided as a single unit spanning the entire width direction, but rather are divided and provided at both ends in the width direction. This improves the ease of manually inserting the sheet P compared to the case where the first guide section 75 and the second guide section 76 are provided across the entire width. In other words, it becomes easier to set the sheet P somewhat loosely between the first guide section 75 and the second guide section 76 when inserting it by hand. In addition, it reduces the sliding resistance that the first guide section 75 and the second guide section 76 impart to the sheet P when the sheet P moves in the conveying direction.

[0029] In this embodiment, as shown in Figure 2, both the first guide portion 75 and the second guide portion 76 are formed such that the distance between them and the mounting surface 71a gradually decreases from the upstream side to the downstream side in the conveying direction. In other words, as shown in Figure 2, the first guide portion 75 and the second guide portion 76 are not parallel to the mounting surface 71a, but are formed to be inclined downward from the right to the left. With this configuration, the sheet P inserted by hand from the upstream side moves smoothly along the downward-sloping mounting surface 71a toward the positions of the limiting rollers 81-86, guided by the first guide section 75 and the second guide section 76. As a result, the ease of setting the sheet P into the feeding device 70 is improved.

[0030] Furthermore, in this embodiment, as shown in Figures 3 and 4(C), the multiple limiting rollers 81 to 86 are each divided and installed on a pair of side fences 72 and 73, and are not positioned in the center in the width direction. In other words, as shown in Figures 3 and 4(C), the limiting rollers 81 to 86 are not provided as a single unit across the entire width direction, but rather are divided and provided at both ends in the width direction. As a result, compared to the case where the limiting rollers 81-86 are provided across the entire width, the uncurled portion (central part) of the sheet P is less restricted (a space is secured for the uncurled portion to escape during curl correction), making it easier to correct the curl of the sheet P overall. In addition, the sliding resistance that the limiting rollers 81-86 impart to the sheet P when the sheet P moves in the conveying direction can be reduced.

[0031] The operation of sheet P in the feeding device 70 will be explained below using Figures 4 and 5. First, as shown in Figure 4(A), the user manually inserts the sheet P so that its leading edge rests on the first guide portion 75. Then, as shown in Figure 4(B), the sheet P continues to fall along the slope under its own weight (or is inserted by the user) so that its rear end remains on the first guide portion 75 and the upper surface of its leading edge is guided by the second guide portion 76. In addition, the skew of the sheet P is corrected in Figures 4(A) and (B). Subsequently, as shown in Figure 4(C), the sheet P, guided by the first and second guide sections 75 and 76, moves to the position of the limiting rollers 81 to 86, where it is gradually compressed between the mounting surface 71a and the multiple limiting rollers 81 to 86, thereby correcting the curl. Also, in Figures 4(A) to (C), the misalignment of the sheet P in the width direction (lateral resist) is corrected.

[0032] Subsequently, as shown in Figure 5(A), the sheet P, whose curl has been corrected by the limiting rollers 81-86, is held between the vertical walls 72b and 73b (with the lateral resist corrected) and is conveyed at a constant speed by the multiple conveyor rollers 90-92 while maintaining its curl-corrected state. In addition, as shown in Figures 4(A)-(C) and 5(A), the upward air ejection from the multiple holes 71a1 (air blowers 74) reduces problems such as the sheet P sticking to the mounting surface 71a and jamming or skewing (poor feeding). The sheet P, which has been transported by multiple transport rollers 90-92, is then guided by guide members 97 and 98 (see Figures 2 and 3) toward the nip of the brush roller pair 95. Then, as shown in Figure 5(B), the sheet P is conveyed towards the feed roller pair 55 while maintaining its straightened curl state and further strengthening the straightening of the curl by the brush roller pair 95.

[0033] As described above, the feeding device 70 in this embodiment is a feeding device that feeds a sheet P in a predetermined transport direction, and is equipped with a mounting section 71 having a mounting surface 71a on which a sheet P can be placed. A first guide section 75 that can contact the lower surface of a manually inserted sheet P is positioned at a height distance from the mounting surface 71a and on the upstream side in the transport direction. A second guide section 76 that can contact the upper surface of a sheet P is positioned at a height distance from the mounting surface 71a and on the downstream side in the transport direction relative to the first guide section 75. A plurality of limiting rollers 81 to 86 that can contact the upper surface of a sheet P are arranged in parallel on the downstream side in the transport direction relative to the second guide section 76, and are arranged such that the distance to the mounting surface 71a gradually decreases as the position in the transport direction moves downstream. Transport rollers 90 to 92 that transport the sheet P placed on the mounting surface 71a in the transport direction are installed on the downstream side in the transport direction relative to the plurality of limiting rollers 81 to 86. Furthermore, a pair of brush rollers 95, which transport the sheet P conveyed by the transport rollers 90-92 in the transport direction, is installed downstream of the mounting surface 71a and the transport rollers 90-92 in the transport direction. Guide members 97 and 98 are also installed to guide the sheet P conveyed by the transport rollers 90-92 toward the nip of the brush roller pair 95. A pair of side fences 72 and 73 are also installed to restrict the position of the sheet P in the width direction perpendicular to the transport direction. In addition, a blower 74 is installed to blow air upward from a plurality of holes 71a1 formed in the mounting surface 71a. This reduces the likelihood of sheet feeding problems, regardless of the direction of curl in sheet P.

[0034] In this embodiment, the present invention was applied to a feeder 70 installed in a monochrome image forming apparatus 1, but it can naturally also be applied to a feeder installed in a color image forming apparatus. Furthermore, although this embodiment applies the present invention to a feeding device 70 installed in an electrophotographic image forming apparatus 1, the application of the present invention is not limited to this, and it can also be applied to feeding devices installed in other types of image forming apparatuses (for example, inkjet image forming apparatuses, stencil printing machines, etc.). Furthermore, in this embodiment, the present invention was applied to the feeding device 70 in the image forming apparatus 1 where the image forming sheet P is set, but the present invention can also be applied to the document transport unit 10 (automatic document transport device) which is a feeding device in which the original document D as a sheet is set. In this embodiment, the pair of side fences 72 and 73 are formed to extend across the entire transport direction on the mounting surface 71a. Alternatively, the pair of side fences 72 and 73 can be formed to extend from the upstream side (right end in Figures 2 and 3) on the mounting surface 71a to the vicinity of the downstream limiting roller 86 among the multiple limiting rollers 81 to 86. In that case, near the downstream limiting roller 86, the sheet P, with its widthwise misalignment (lateral resist) corrected by the vertical wall portions 72b and 73b, will be transported towards the transport rollers 90 to 92. Furthermore, even in such cases, the same effects as those of this embodiment can be obtained.

[0035] It is clear that the present invention is not limited to this embodiment, and that this embodiment can be modified as appropriate within the scope of the technical concept of the present invention, in addition to what is suggested here. Furthermore, the number, position, shape, etc. of the constituent members are not limited to this embodiment, and can be set to a number, position, shape, etc. that is suitable for carrying out the present invention.

[0036] In this specification, the term "sheet" is defined to include all sheet-like recording media, such as coated paper, label paper, OHP sheets, metal sheets, and films, in addition to ordinary paper. [Explanation of Symbols]

[0037] 1. Image forming apparatus (image forming apparatus main unit), 55 feeding roller pairs, 70 Feeding device (manual feeding device), 71. Mounting section (manual feed tray), 71a Mounting surface (tray surface), 71a1 Hole (spout), 72, 73 Side fences, 72a, 73a sloped section, 72b, 73b vertical wall section, 74. Blower, 75. First Guide Section, 76 Second Guide Section, 81-86 Restriction rollers, 90-92 Conveyor rollers, 95 brush roller pairs, 97, 98 Guide members, P-seat.

[0038] Furthermore, the embodiments of the present invention can also be, for example, combinations of appendices 1 to 8 as follows. (Note 1) A feeding device that feeds sheets in a predetermined conveying direction, A mounting section having a mounting surface on which the aforementioned sheet can be placed, A first guide portion is positioned at a height distance from the mounting surface and on the upstream side in the transport direction, and is capable of contacting the lower surface of the manually inserted sheet, A second guide portion is positioned at a height distance from the mounting surface and downstream of the first guide portion in the transport direction, and is capable of contacting the upper surface of the sheet, Multiple limiting rollers are arranged parallel to the second guide section on the downstream side in the conveying direction, and are positioned such that the distance to the aforementioned surface decreases as the position in the conveying direction moves downstream, and are capable of contacting the upper surface of the sheet. A conveying roller is installed downstream of the plurality of limiting rollers in the conveying direction and conveys the sheet placed on the aforementioned surface in the conveying direction, A pair of brush rollers is installed downstream of the mounting surface and the conveying roller in the conveying direction, and conveys the sheet conveyed by the conveying roller in the conveying direction. A guide member that guides the sheet conveyed by the conveyor roller toward the nip of the brush roller pair, A pair of side fences are formed on the mounting surface so as to extend from the upstream side to the position of the downstreammost of the plurality of limiting rollers, thereby limiting the position of the sheet in the width direction perpendicular to the conveying direction, A blower that ejects air upward from a plurality of holes formed in the mounting surface, A feeding device characterized by being equipped with the following features. (Note 2) The feeding device according to Appendix 1, characterized in that the plurality of holes are arranged such that the ends are denser than the central part in the width direction. (Note 3) The aforementioned side fence is From the uppermost upstream side to the position of the uppermost limiting roller among the plurality of limiting rollers, the spacing in the width direction is formed to gradually decrease from the upstream side to the downstream side in the conveying direction, The spacing in the width direction is constant from the mounting surface to a predetermined height position, and the spacing in the width direction gradually increases as the height position rises from the predetermined height position. The feeding device according to Appendix 1 or Appendix 2, characterized in that the first guide section and the second guide section are each installed separately on the pair of side fences and are not located in the central part in the width direction. (Note 4) The feeding device according to any one of the appendices 1 to 3, characterized in that both the first guide portion and the second guide portion are formed such that the distance between them and the aforementioned surface gradually decreases from the upstream side to the downstream side in the conveying direction. (Note 5) The feeding device according to any one of the appendices 1 to 4, characterized in that the plurality of limiting rollers are each installed separately on the pair of side fences and are not located in the central part in the width direction. (Note 6) The conveying device according to any one of the appendices 1 to 5, wherein the conveying rollers are a plurality of conveying rollers arranged in parallel in the conveying direction, and the sheet on the aforementioned surface is conveyed at a constant speed. (Note 7) The feeding device according to any one of the appendices 1 to 6, characterized in that the mounting surface is a plane that slopes downward from the upstream side to the downstream side in the conveying direction. (Note 8) An image forming apparatus characterized by being equipped with a feeding device described in any of the appendices 1 to 7. [Prior art documents] [Patent Documents]

[0039] [Patent Document 1] Japanese Patent Publication No. 2005-298166

Claims

1. A feeding device that feeds sheets in a predetermined conveying direction, A mounting section having a mounting surface on which the aforementioned sheet can be placed, A first guide portion is positioned at a height distance from the mounting surface and on the upstream side in the transport direction, and is capable of contacting the lower surface of the manually inserted sheet, A second guide portion is positioned at a height distance from the mounting surface and downstream of the first guide portion in the conveying direction, and is capable of contacting the upper surface of the sheet. Multiple limiting rollers are arranged parallel to the second guide section on the downstream side in the conveying direction, and are positioned such that the distance to the aforementioned surface decreases as the position in the conveying direction moves downstream, and are capable of contacting the upper surface of the sheet. A conveying roller is installed downstream of the plurality of limiting rollers in the conveying direction and conveys the sheet placed on the aforementioned surface in the conveying direction, A pair of brush rollers is installed downstream of the mounting surface and the conveying roller in the conveying direction, and conveys the sheet conveyed by the conveying roller in the conveying direction. A guide member that guides the sheet conveyed by the conveyor roller toward the nip of the brush roller pair, A pair of side fences that restrict the position of the sheet in the width direction perpendicular to the conveying direction, A blower that ejects air upward from a plurality of holes formed in the mounting surface, A feeding device characterized by being equipped with the following features.

2. The feeding device according to claim 1, characterized in that the plurality of holes are arranged such that the ends are denser than the central part in the width direction.

3. The aforementioned side fence is From the uppermost upstream side to the position of the uppermost limiting roller among the plurality of limiting rollers, the spacing in the width direction is formed to gradually decrease from the upstream side to the downstream side in the conveying direction, The spacing in the width direction is constant from the mounting surface to a predetermined height position, and the spacing in the width direction gradually increases as the height position rises from the predetermined height position. The feeding device according to claim 1 or 2, characterized in that the first guide section and the second guide section are each installed separately on the pair of side fences and are not located in the central part in the width direction.

4. The feeding device according to claim 1 or 2, characterized in that both the first guide portion and the second guide portion are formed such that the distance between them and the aforementioned surface gradually decreases from the upstream side to the downstream side in the conveying direction.

5. The feeding device according to claim 1 or 2, characterized in that the plurality of limiting rollers are each installed separately on the pair of side fences and are not located in the central part in the width direction.

6. The conveying device according to claim 1 or 2, wherein the conveying rollers are a plurality of conveying rollers arranged in parallel in the conveying direction, and convey the sheet on the aforementioned surface at a constant speed.

7. The feeding device according to claim 1 or 2, characterized in that the mounting surface is a plane that slopes downward from the upstream side to the downstream side in the conveying direction.

8. An image forming apparatus characterized by comprising the feeding device described in claim 1 or claim 2.

Images