Feeding device, image forming apparatus, and image forming system

Abstract

This allows for efficient handling of the sheets loaded in the loading area, reducing the likelihood of feeding problems. [Solution] A feeding device for feeding sheets P in the feeding direction, comprising a liftable curved plate 72 (mounting section) having a mounting surface capable of loading multiple sheets P, and a blower 76 that blows air toward the end faces in the width direction perpendicular to the feeding direction of the multiple sheets P loaded on the curved plate 72. The mounting surface of the curved plate 72 is curved in a convex shape upward from both ends in the width direction toward the center, either in whole or in part.

Description

Technical Field

[0001] The present invention relates to a feeding device for feeding sheets such as paper, 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, and an image forming system detachably installed in the image forming apparatus.

Background Art

[0002] Conventionally, in a feeding device in an image forming apparatus or an image forming system such as a copying machine, a printer, or a printing machine, an air blowing device that blows air against the end faces in the width direction of the stacked sheets to separate the sheets that are stacked and adhered to each other in the vertical direction has been widely known (see, for example, Patent Document 1).

[0003] On the other hand, Patent Document 2 discloses a technique for forming the central portion of the stacking surface of a sheet tray in a convex shape for the purpose of feeding a sheet with a curled tip portion on the sheet tray well.

Summary of the Invention

Problems to be Solved by the Invention

[0004] Even if a conventional feeding device is provided with an air blowing device for separating the adhered sheets, when sheets that are likely to adhere, such as coated paper, are stacked, the separation (unloading) of the sheets is insufficient, and feeding failures such as non-feeding and double-feeding occur. In order to solve such problems, even if the technique of Patent Document 2 is applied and the central portion of the placement surface (stacking surface) is protruded in a convex shape, since there is a step on the placement surface, it has not been possible to feed the last sheet of the stacked sheets sufficiently well.

[0005] The present invention has been made to solve the above-described problems, and an object thereof is to provide a feeding device, an image forming apparatus, and an image forming system that can sufficiently unload the sheets stacked on the placement portion and are less likely to cause feeding failures. [Means for solving the problem]

[0006] The feeding device in this invention is a feeding device for feeding sheets in a feeding direction, comprising: a liftable mounting section having a mounting surface capable of loading multiple sheets; and a blower that blows air toward the end faces in the width direction perpendicular to the feeding direction of the multiple sheets loaded on the mounting section, wherein the mounting surface of the mounting section is curved in a convex shape upward from both ends in the width direction toward the center, in whole or in part. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a feeding device, an image forming apparatus, and an image forming system that can adequately handle sheets loaded in a mounting section and are less prone to feeding failures. [Brief explanation of the drawing]

[0008] [Figure 1] This is an overall configuration diagram showing an image forming system 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 perspective view showing a feeding device on which sheets are loaded. [Figure 4] This is a perspective view showing the main components of the feeding device. [Figure 5] This is a front view showing the feeding device. [Figure 6] This diagram shows the state of air being blown onto the edges of multiple sheets. [Figure 7] (A) A front view showing the feeding device with a small curvature of the curved plate, and (B) A front view showing the feeding device with a large curvature of the curved plate. [Figure 8] This is a perspective view of the feeding device from below. [Figure 9] This diagram shows the control flow performed by the feeding device. [Figure 10] This is a hardware configuration diagram for a feeding device. [Figure 11] This flowchart shows an example of control performed by a feeding device. [Figure 12] This is a top view showing a feeding device, as an example of modification 1. [Figure 13] In the feeding device shown in Figure 12, (A) is a front view showing the state in which the curvature of the curved plate is small, and (B) is a front view showing the state in which the curvature of the curved plate is large. [Figure 14] Figure 12 is a perspective view of the feeding device from below. [Figure 15] In another form of feeding device, (A) a front view showing the curved plate with a large curvature, and (B) a front view showing the curved plate with a small curvature. [Figure 16] As a modified example 2, the feeding device is shown as follows: (A) a front view showing the curved plate with a large curvature, and (B) a front view showing the curved plate with a small curvature. [Figure 17] Figure 16 is a flowchart showing an example of the control performed by the feeding device. [Figure 18] As a third modified example, the feeding device is shown as follows: (A) a front view showing the curved plate with a large curvature, and (B) a front view showing the curved plate with a small curvature. [Figure 19] In the feeding device shown in Figure 18, (A) is a perspective view showing the state in which the curvature of the curved plate is large, and (B) is a perspective view showing the state in which the curvature of the curved plate is small. [Figure 20] This is a perspective view showing the main parts of the feeding device, as a modified example (modification 4). [Figure 21] Figure 20 is a top view showing the main parts of the feeding device. [Figure 22] (A) A top view and (B) A front view showing the main parts of a different type of feeding device. [Figure 23] This is a diagram showing the overall configuration of an image forming system, as a modified example (5). [Figure 24] Figure 23 is a diagram showing the configuration of the feeding device in the image forming system. [Figure 25] This is an overall configuration diagram showing an image forming apparatus as a modified example 6.

Embodiments of the Invention

[0009] Hereinafter, embodiments for implementing this invention will be described in detail with reference to the drawings. In each figure, the same or corresponding parts are denoted by the same reference numerals, and the redundant description will be simplified or omitted as appropriate.

[0010] First, in FIG. 1, the overall configuration and operation of the image forming system 200 will be described. The image forming system 200 in the present embodiment is such that a feeding device 70 (high-capacity feeding device) for storing a large amount of sheets P is detachably installed on the image forming apparatus 1 as an optional device. Then, in the image forming apparatus 1, an image is formed on the sheet fed from the feeding device 70.

[0011] First, the configuration of the image forming apparatus 1 will be described. In FIG. 1, 1 is a copying machine as an image forming apparatus, 2 is an original reading unit for optically reading the image information of the original D, and 3 is an exposure unit for irradiating the exposure light L based on the image information read by the original reading unit 2 onto the photosensitive drum 5. Also, 4 is an image forming unit for forming a toner image (image) on the photosensitive drum 5, 7 is a transfer roller that abuts on the photosensitive drum 5 via the transfer conveyance belt 8 to form a transfer nip, 8 is a transfer conveyance belt for transferring and conveying the toner image formed on the photosensitive drum 5 to the sheet P, and 10 is an original conveyance unit (automatic document feeder) for conveying the set original D to the original reading unit 2. Also, 12 and 13 are paper feed cassettes (feeding devices) incorporated in the image forming apparatus 1 for storing sheets P such as paper, and 17 is a registration roller (timing roller) for conveying the sheet P toward the transfer nip. Furthermore, 20 indicates a fixing device that fixes the toner image (unfixed image) supported on the sheet P, 21 is a fixing roller installed in the fixing device 20, 22 is a pressure roller installed in the fixing device 20, 31 is an output tray on which sheets P ejected from the main body of the device 1 are loaded, and 100 is an operation display panel on which operation buttons for displaying various information and performing operations on the device are displayed. Here, 70 is a feeding device (high-capacity feeding device) that stores a large-capacity sheet P, and together with the image forming apparatus 1, it constitutes the image forming system 200.

[0012] Referring to Figure 1, the operation of the image forming system 200 (image forming apparatus 1) during normal image forming will be described. 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.

[0013] 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).

[0014] Meanwhile, the sheet P being transported to the transfer nip operates as follows: First, one of the multiple paper feed cassettes 12, 13 of the image forming apparatus body 1 and the large-capacity paper feed device 70 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 feed mechanism 52 (composed of a feed roller, feed 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 a large-capacity feeding device 70 (large-capacity feeding device) installed on the side of the main body 1 is selected, the uppermost sheet P of the multiple sheets P loaded on the curved plate 72 (see Figures 2 to 4, etc.) which serves as the mounting section for the feeding device 70 will be fed by the feeding mechanism 52 (composed of feeding rollers 53, feed rollers 54, backup rollers 55, etc.) toward the transport path where the transport rollers 56 are installed, and then reach the position of the register roller 17. This large-capacity feeding device 70 will be explained in detail later.

[0015] 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.

[0016] Next, the feeding device 70 (large-capacity feeding device) in this embodiment will be described in detail. Referring to Figures 2 to 5, the feeding device 70 is for feeding the sheet P in the feeding direction (the direction of the arrow in Figure 2), and consists of a sheet storage section 71, a feeding mechanism 52, a blower 76, and the like. The sheet storage section 71 is composed of a curved plate 72 as a mounting section (bottom plate), a reference fence 73, an end fence 74, a side fence 75, and the like. In this embodiment, the curved plate 72 that functions as a mounting section (bottom plate) is not formed in a flat shape, but is formed in a curved shape as shown in Figure 4, etc., which will be explained in detail later. The feeding mechanism 52 consists of feeding rollers 53, feed rollers 54, backup rollers 55, etc. The sheets P stored in the sheet storage section 71 are then transported by the feeding mechanism 52 in the feeding direction indicated by the arrows in Figures 2 and 3.

[0017] More specifically, the standard fence 73 is formed to stand vertically upward on the downstream side in the feeding direction of the sheet storage section 71 (curved plate 72). The curved plate 72 (mounting section) is formed to allow multiple sheets P to be stacked in contact with the reference fence 73. The curved plate 72 is also configured to be able to move up and down so that the uppermost sheet P is at a predetermined height (as shown in Figures 2, 3, and 5), regardless of the number of sheets P stacked. In other words, the curved plate 72 is for stacking multiple sheets P, and depending on the height of the stacked sheets P (the number of remaining sheets P detected by the remaining quantity detection sensor 63 shown in Figures 9, 10, 16, etc.), it moves up and down along the reference fence 73 by the lifting mechanism 111-113 (see Figure 3) (in the direction of the white double arrows in Figure 2).

[0018] As shown in Figure 3, the lifting mechanism consists of a lifting motor 111, a fixed pulley 112, a wire 113, and the like. When the lifting motor 111 is driven to rotate in the forward direction by the control unit 60 (see Figure 10), the wire 113 wound around the fixed pulley 112 is wound onto the winding section, causing the curved plate 72 (mounting section) to rise. In contrast, when the lifting motor 111 is driven to rotate in the opposite direction by the control unit 60, the winding of the wire 113 is released, and the curved plate 72 (mounting section) descends.

[0019] Referring to Figure 2, the end fence 74 is configured so that its position in the feeding direction (the distance from the reference fence 73) can be manually (or automatically) adjusted according to the size of the sheet P in the feeding direction (the left-right direction in Figure 2). The pair of side fences 75 are configured so that their spacing (opposing distance) in the width direction can be manually (or automatically) varied according to the size of the sheet P in the width direction (the direction perpendicular to the feeding direction, the direction perpendicular to the plane of the paper in Figure 2, and the left-right direction in Figure 5). Each of the pair of side fences 75 is provided with a blower 76 that blows air from the side toward the end faces of the sheets P (especially the uppermost sheet P and the sheets P below it) loaded on the curved plate 72 (mounting section) to separate the sheets P and isolate the uppermost sheet P. By providing the blower 76, the sheets P that are in close contact with each other are separated, reducing problems such as multiple sheets P being fed on top of each other (overfeeding) or not being fed at all (jamming). The user places the grasped sheet P (sheet bundle) onto the mounting surface (upper surface) of the curved plate 72 (mounting section) so that it abuts against the reference fence 73. Then, the user moves the side fence 75 and end fence 74 so that they abut against the mounted sheet P, completing the setting of the sheet P (sheet bundle) into the sheet storage section 71. Furthermore, as shown in Figures 4 and 5, the pair of side fences 75 in this embodiment are provided with sheet-holding portions 75a to restrict the upward lifting of the sheet P loaded on the curved plate 72 (mounting portion). In this embodiment, the side fence 75 and the end fence 74 are configured to be movable. However, in order to store a large capacity of highly versatile sheets P, such as A4 size, the positions of the side fence 75 and the end fence 74 can also be fixed (made immovable) to match the size of the sheet.

[0020] As shown in Figure 2, the feeding mechanism 52 consists of a feed roller 54, a feeding roller 53, a backup roller 55, and the like. The feed roller 54 is installed on the leading edge side in the feeding direction (the direction of the white arrow in Figure 2, which is the conveying direction) relative to the sheet P loaded on the curved plate 72 (mounting section), and contacts the upper surface of the sheet P and rotates along the feeding direction of the sheet P (clockwise rotation in Figure 2) to feed the sheet P in the feeding direction indicated by the arrow. The feed roller 53, while in contact with the surface (upper surface) of the sheet P loaded on the curved plate 72 (mounting section), rotates clockwise in Figure 2 along the direction of travel, thereby transporting the sheet P toward the position of the feed roller 54. The backup roller 55 is positioned to form a nip section between itself and the feed roller 54. The backup roller 55 rotates in the forward direction (counterclockwise in Figure 2) along the feeding direction when one sheet P is held in the nip section and when no sheet P is held in the nip section. Conversely, when multiple sheets are held in the nip section, the backup roller 55 rotates in the opposite direction to the forward direction (clockwise in Figure 2). As a result, the uppermost sheet P of the multiple sheets P held in the nip section is fed in the feeding direction along with the rotation of the feed roller 54, and the lower sheets P are conveyed in the opposite direction to the feeding direction (forward direction), thereby preventing double feeding of sheets P. Furthermore, the feeding mechanism 52 for the feeding cassettes 12 and 13 (see Figure 1) built into the image forming apparatus 1 is configured and operates in much the same way as the feeding mechanism 52 for the large-capacity feeding device 70 described above.

[0021] The following describes in detail the characteristic configuration and operation of the feeding device 70 (large-capacity feeding device) in this embodiment. As explained earlier using Figures 2 to 5, the feeding device 70 is provided with a curved plate 72 which serves as a liftable mounting section (bottom plate) with a mounting surface capable of holding multiple sheets P (sheet bundles). Furthermore, the opposing distance in the width direction (the left-right direction in Figures 5 and 7) can be increased or decreased, and a pair of side fences 75 are provided to restrict the position of the sheet P placed on the curved plate 72 (mounting section) in the width direction. Furthermore, a blower 76 is provided that blows air toward the end faces in the width direction (a direction perpendicular to the feeding direction, which is the left-right direction in Figures 5 and 7) of the multiple sheets P loaded on the curved plate 72 (mounting section). This blower 76 consists of a suction fan that draws in air from the outside in the width direction of the side fence 75 and exhausts it toward the inside in the width direction, and is installed on each of the pair of side fences 75.

[0022] Here, as shown in Figures 4 and 5, in this embodiment, the curved plate 72, which serves as the mounting section (bottom plate), has its entire mounting surface (the upper surface of the mounting section on which the sheets P are stacked) curved upward in a convex shape from both ends in the width direction toward the center (it is formed to be curved). In other words, in this embodiment, a mounting surface that is curved (flexible) is used as the mounting part, rather than a flat surface (non-bendable) mounting part. In this embodiment, the curved plate 72 (mounting part) is not curved in the feeding direction, but is curved in the width direction.

[0023] Thus, in this embodiment, since a curved plate 72 is used as the loading section, even when sheets P that tend to stick together, such as coated paper, are loaded, the sheets P are handled (separated) sufficiently, making it less likely for feeding defects such as non-feeding or double feeding to occur, and allowing all the loaded sheets P to be fed smoothly until the very last one. As shown in Figure 6(B) as a comparative example, when sheets P (sheet bundles) are stacked on a flat mounting surface, the end faces are neatly aligned, and the area to which air is blown from the blower 76 in the direction of the white arrow is relatively small. In contrast, as in the embodiment shown in Figure 6(A), when sheets P (sheet bundles) are stacked on a curved plate 72 (mounting surface), the end faces are offset in a stepped manner in the height direction (the adhesion force is reduced, and they are somewhat separated), and the area to which air is blown from the blower 76 is wider than in Figure 6(B). Therefore, the blower 76 is more effective at separating the sheets P.

[0024] In this embodiment, the curved plate 72, which serves as the mounting portion, has its entire mounting surface formed on its upper surface. That is, the entire upper surface of the curved plate 72 functions as a mounting surface. Furthermore, the curved plate 72 (supporting portion) in this embodiment has elasticity. Specifically, the curved plate 72 is made of a thin sheet of stainless steel or the like, and has sufficient rigidity to support multiple sheets P, while also having enough elasticity to allow the curvature (degree of bending) to be varied depending on the magnitude of the force acting on both ends in the width direction.

[0025] As shown in Figures 7 and 8, the feeding device 70 in this embodiment is provided with variable means 115 to 117 for varying the curvature of the curved plate 72 (mounting portion). This variable mechanism mainly consists of a wire 117 connected to the corner of the curved plate 72, a winding member 116 capable of winding the wire 117, and a winding motor 115 capable of rotating the winding member 116 in both forward and reverse directions. It is integrally installed on the lower surface of the curved plate 72 (the surface opposite the mounting surface) and moves up and down together with the curved plate 72.

[0026] Then, when the winding motor 115 is driven to rotate in the forward direction by the control unit 60 (see Figures 9 and 10), the winding member 116 winds the wire 117, causing the corners to be pulled by the wire 117, and the curved plate 72 bends significantly (the curvature increases) as shown in Figure 7(B). In contrast, when the winding motor 115 is driven to rotate in the reverse direction by the control unit 60, the winding of the wire 117 by the winding member 116 is released, and the curved plate 72 bends slightly due to its elasticity, as shown in Figure 7(A) (its curvature becomes smaller). The fixing member 118 shown in Figure 7 is a member for fixing and holding the curved plate 72 to the side fence in a manner that allows for variable curvature.

[0027] In this embodiment, the variable means 115 to 117 are configured to vary the curvature of the curved plate 72 according to at least one of the type, size, and thickness of the sheet P loaded on the curved plate 72 (mounting section). More specifically, in this embodiment, when a sheet P that adheres easily, such as coated paper or label paper (the type of which is pre-stored in the memory unit 124 (see Figure 10)), is set on the curved plate 72, the control unit 60 controls the curvature of the curved plate 72 to increase, as shown in Figure 7(B). When a sheet P that does not adhere easily (such as plain paper) is set on the curved plate 72, the control unit 60 controls the curvature of the curved plate 72 to decrease, as shown in Figure 7(A). More specifically, when the maximum number of sheets P that adhere easily are set, the amount of wire 117 wound by the winding member 116 is set to 40 mm, and the curvature of the curved plate 72 is controlled to be large, as shown in Figure 7(B). Conversely, when the maximum number of sheets P that do not adhere easily are set, the amount of wire 117 wound by the winding member 116 is set to 0 mm, and the curvature of the curved plate 72 is controlled to be almost zero, as shown in Figure 7(A).

[0028] In this embodiment, the curvature of the curved plate 72 was varied according to the type of sheet P. However, even with ordinary paper, if the adhesion between sheets P changes depending on the size and thickness (basis weight) of the sheets P, the curvature of the curved plate 72 may be varied accordingly. Furthermore, the curvature of the curved plate 72 can be adjusted in three or more stages depending on the degree to which the sheet P adheres to it. Furthermore, sheet information regarding the type, size, and thickness of sheet P can be determined by the control unit 60 based on information input by the user via the operation display panel 100 (see Figure 1).

[0029] Furthermore, in this embodiment, the variable means 115 to 117 vary the curvature of the curved plate 72 according to the frequency of non-feeding (jamming) of the sheet P fed from the feeding device 70. More specifically, as shown in Figure 2, a non-feeding detection sensor 62 (non-feeding detection means) capable of optically detecting the sheet P passing through its position is installed downstream of the feed roller 53 in the feeding direction and upstream of the nip portion between the feed roller 54 and the backup roller 55 in the feeding direction. If the leading edge of the sheet P (the uppermost sheet P loaded on the curved plate 72) is not detected even after a predetermined time (measured by the timer 125 shown in Figure 10) has elapsed since the feeding of the sheet P by the feed roller 53 began, the control unit 60 determines that the feeding by the feed roller 53 has failed and a non-feeding (jam) has occurred. Specifically, in this embodiment, if the non-feeding detection sensor 62 detects a predetermined number of non-feedings (for example, 3 times) after the sheets P of the feeding device 70 have been set, it is assumed that the non-feeding is due to strong adhesion between the set sheets P. In this case, the amount of wire 117 wound by the winding member 116 is increased by 10 mm compared to before, and the curvature of the curved plate 72 is controlled to increase. As a result, the adhesion between the sheets P loaded on the feeding device 70 (curved plate 72) is reduced, making it less likely for non-feeding to occur by the feeding rollers 53.

[0030] Referring to Figure 9, the control unit 60 receives sheet information input to the operation display panel 100 and information regarding non-feeding (jamming) detected by the non-feeding detection sensor 62, and the winding motor 115 is driven and controlled based on this information. As shown in Figure 10, the control unit 60 consists of a CPU 121 (Central Processing Unit), RAM 122 (Random Access Memory), ROM 123 (Read Only Memory), and storage unit 124, all connected via a bus 120. The CPU 121 is the arithmetic unit and controls the overall operation of the image forming system 200. The RAM 122 is a volatile storage medium that allows for high-speed reading and writing of information. When the CPU 121 processes information, the RAM 122 is used as the CPU 121's workspace. The ROM 123 is a read-only non-volatile storage medium that stores programs such as firmware. The memory unit 124 is a non-volatile storage medium capable of reading and writing information, and stores the OS (Operating System), various control programs, and application programs, etc. The memory unit 124 is, for example, an SSD (Solid State Drive) or an HDD (Hard Disk Drive). The control unit 60 then acquires information from the operation display panel 100, timer 125, non-feed detection sensor 62, remaining amount detection sensor 63, winding motor 115, lifting motor 111, blower 76, etc., via the bus 120, and controls them.

[0031] Below, an example of the control performed by the feeding device 70 will be explained using the flowchart in Figure 11. As shown in Figure 11, when a user commands a feed from the feeder 70 by operating the operation display panel 100, the sheet information entered into the operation display panel 100 (in the example in Figure 11, this is the type of sheet P set in the feeder 70) is first acquired in preparation for starting the feed (step S1). Then, the acquired sheet information (sheet type) is compared with sheet information pre-stored in the memory unit 124 to determine whether it is easy to adhere to (step S2). As a result, if the sheet P is easy to adhere to, the winding motor 115 is driven to increase the curvature of the curved plate 72 from the standard state (a state where the curvature is small) (step S3). If the sheet P is not easy to adhere to, the winding motor 115 is not driven (the curvature of the curved plate 72 is left as is), and the preparation for feeding is completed (step S4). Then, when feeding from the feeding device 70 begins, it is determined, based on the detection result of the non-feeding detection sensor 62, whether a predetermined number of non-feeding cycles N has been reached since the sheet P was set (loaded) in the feeding device 70 (steps S5, S6). As a result, if the predetermined number of non-feeding cycles N has been reached, the winding motor 115 is driven to increase the curvature of the curved plate 72 from the state in step S4 (increase the curvature) (step S7), and if the sheet P is difficult to adhere to, the winding motor 115 is not driven (the curvature of the curved plate 72 is left as it was in step S4). Then, in the former case, feeding is resumed, and in the latter case, feeding is continued (step S8).

[0032] <Example 1> As shown in Figures 12 to 14, in the feeding device 70 of the modified example 1, the variable means is configured to vary the curvature of the curved plate 72 in conjunction with an increase or decrease in the opposing distance between a pair of side fences 75 (an opposing distance adjusted to match the widthwise size of the sheet P). As shown in Figure 12, the pair of side fences 75 in Modification 1 are also configured to be movable in the width direction by a rack and pinion mechanism, similar to those described using Figure 3, etc. Each of the pair of side fences 75 has a rack bar 86 extending in the width direction below the curved plate 72. Each of these rack bars 86 has a rack gear 86a formed on it, and these rack gears 86a mesh with a pinion gear 85 (which is positioned between the two rack bars 86). With this configuration, the pair of side fences 75 move together in the width direction to increase or decrease the distance between them in the width direction. As shown in Figures 13 and 14, both ends of the curved plate 72 in the width direction are fixed to the lower part of a pair of side fences 75 by fixing members 119. With this configuration, as shown in Figure 13(A), when a sheet P with a large width direction is set in the feeding device 70, the curvature of the curved plate 72 is set to be small, and as shown in Figure 13(B), when a sheet P with a small width direction is set in the feeding device 70, the curvature of the curved plate 72 is set to be large. This configuration is useful when the contact between sheets P becomes stronger when sheets P with a small width direction are loaded compared to when sheets P with a large width direction are loaded. In contrast, when a sheet P with a large width is loaded, the contact between the sheets P becomes stronger compared to when a sheet P with a small width is loaded. In such cases, as shown in Figure 15(A), the curvature of the curved plate 72 is set to be large when a sheet P with a large width is set in the feeding device 70, and as shown in Figure 15(B), the curvature of the curved plate 72 is set to be small when a sheet P with a small width is set in the feeding device 70. In the feeding device 70 shown in Figure 15, the widthwise ends of the curved plate 72 are connected to the lower part of the side fence 75 via rack and pinion mechanisms 130 and 131. Furthermore, even in the feeding device 70 configured as in Modification 1, the sheets P loaded on the curved plate 72 (mounting section) can be handled sufficiently, making feeding failures less likely.

[0033] <Modification 2> As shown in Figures 16 and 17, in the feeding device 70 of the modified example 2, the variable means 115 to 117 are configured to vary the curvature of the curved plate 72 based on the detection result of the remaining amount detection sensor 63, which is a detection means for detecting the remaining number of sheets P (stacking height) stacked on the curved plate 72 (placement section). As shown in Figure 16, the variable means in the modified example 2 is also composed of a wire 117, a winding member 116, a winding motor 115, etc., similar to those described using Figures 7 and 8. Furthermore, in the modified example 2, the side fence 75 also has multiple remaining quantity detection sensors 63 arranged in the height direction to optically detect the number of sheets P remaining (stacking height) on the curved plate 72. These multiple remaining quantity detection sensors 63 optically detect whether or not sheets P are present at each position, and even as the feeding operation progresses and the number of remaining sheets P decreases, the curved plate 72 (mounting section) is raised by the control unit 60's control of the lifting motor 111 (see Figures 3, 9, and 10) so that the uppermost remaining quantity detection sensor 63 continues to detect sheets P until the very end. As the number of remaining sheets P decreases, the remaining quantity detection sensors 63 stop detecting sheets P sequentially from the lower ones. Then, as shown in Figure 16(A), if the control unit 60 determines that there are many sheets P remaining based on the detection result of the remaining amount detection sensor 63, the lifting motor 111 is controlled so that the curved plate 72 is positioned downwards, and the winding motor 115 is controlled so that the curved plate 72 is bent significantly (the curvature increases). In contrast, as shown in Figure 16(B), if the control unit 60 determines that there are few sheets of sheet P remaining based on the detection results of the remaining amount detection sensor 63, the lifting motor 111 is controlled so that the curved plate 72 is positioned upwards, and the winding motor 115 is controlled so that the curved plate 72 is slightly bent (the curvature becomes smaller). More specifically, when the number of remaining sheets P (plain paper) is 100% of the maximum stackable capacity, the amount of wire 117 wound by the winding member 116 is set to 40 mm, and the curvature of the curved plate 72 is controlled to increase as shown in Figure 16(A). When the number of remaining sheets P (plain paper) is 50% of the maximum stackable capacity, the amount of wire 117 wound by the winding member 116 is reduced by 10 mm, and the curvature of the curved plate 72 is controlled to decrease. Furthermore, as the number of remaining sheets P (plain paper) approaches 0%, the amount of wire 117 wound by the winding member 116 is set to 0 mm, and the curvature of the curved plate 72 is controlled to be almost zero as shown in Figure 16(B). This type of control is performed because the more sheets P there are remaining (the higher the stacking height), the greater the adhesion between the sheets P. In the modified example 2, the curvature of the curved plate 72 is optimized in response to such changes in the adhesion between the sheets P, thereby stabilizing the force applied to the sheets P by the blower 76. Below, an example of the control performed by the feeding device 70 described above will be explained using the flowchart in Figure 17. As shown in Figure 17, once the user has finished setting the sheets P (sheet bundle) into the feeding device 70 (step S10), the remaining number of sheets P is detected by the remaining amount detection sensor 63 before feeding begins (step S11). Based on the detection result in step S11, the amount of wire 117 to be wound by the winding member 116 is determined and the winding operation by the winding member 116 begins (steps S12, S13), and the curvature of the curved plate 72 is optimized. Then, with the curvature of the curved plate 72 optimized in step S13, the feeding operation begins (step S14). In the modified example 2, the number of remaining sheets P is detected in three stages by three remaining quantity detection sensors 63, and the curvature of the curved plate 72 is varied in three stages. However, the number of these stages can also be set to four or more. Furthermore, even in the feeding device 70 configured as in Modification 2, the sheets P loaded on the curved plate 72 (mounting section) can be handled sufficiently, making feeding failures less likely.

[0034] <Variation 3> As shown in Figures 18 and 19, the feeding device 70 in modified example 3 does not use winding mechanisms 115-117 as shown in Figure 16, etc., as variable means, but instead uses one or more pairs of restricting members 89 (in the example of Figure 19, there are two pairs of restricting members 89) that change the curvature of the curved plate 72. These regulating members 89 each have inclined surfaces that contact both ends in the width direction of the curved plate 72, which moves up and down according to the remaining number of sheets P (loading height) loaded on the curved plate 72 (mounting section). The inclined surfaces of one or more pairs of regulating members 89 are formed so that the distance between them gradually increases from bottom to top. In other words, the restricting members 89 that face each other at one end in the width direction and the other end in the width direction have inclined surfaces such that the distance between them in the width direction gradually increases from bottom to top. Then, as shown in Figures 18(A) and 19(A), if the control unit 60 determines that there are many sheets P remaining based on the detection results of the remaining quantity detection sensor 63, the lifting motor 111 is controlled so that the curved plate 72 is positioned downwards, and the curved plate 72 is bent significantly (the curvature increases) due to the narrowed distance between the regulating members 89. In contrast, as shown in Figures 18(B) and 19(B), if the control unit 60 determines that there are few sheets of sheet P remaining based on the detection results of the remaining quantity detection sensor 63, the lifting motor 111 is controlled so that the curved plate 72 is positioned upward, and the curved plate 72 is bent slightly (the curvature becomes smaller) due to the increased distance between the regulating members 89. In this configuration, the curvature of the curved plate 72 can be continuously varied depending on its position in the height direction. Furthermore, even in the feeding device 70 configured as in Modification 3, the sheets P loaded on the curved plate 72 (mounting section) can be handled sufficiently, making feeding failures less likely.

[0035] <Modification 4> As shown in Figures 20 and 21, in the feeding device 70 of the modified example 4, the loading section on which the sheets P are loaded is composed of two curved plates 72 that are divided to form the upstream and downstream sides in the feeding direction on the loading surface, and a horizontal plate 77 that forms the central part in the feeding direction on the loading surface. In other words, in Modification 4, the mounting section is provided with a curved plate 72 on its upper surface, the portion of which has a mounting surface formed thereon. That is, a portion of the mounting surface of the mounting section is curved upward in a convex shape from both ends in the width direction toward the center. To put it another way, the mounting surface of the mounting section is formed by the mounting surfaces of the two curved plates 72 and the mounting surface of the horizontal plate 77. Here, both curved plates 72 have their upper surfaces (mounting surfaces) in the center of the width direction formed to be approximately horizontal, and this portion is on the same plane as the entire upper surface (mounting surface) of the horizontal plate 77. In addition, both curved plates 72 are formed so that the portions other than the horizontal surface in the center of the width direction curve downward toward both ends in the width direction. As shown in Figure 5, the sheets P loaded onto the mounting sections 72 and 77 formed in this manner are also curved, allowing the blower 76 to adequately handle the sheets P, thus reducing the likelihood of feeding problems. Here, in the feeding device 70 of the modified example 4, as explained using Figure 2, the feeding rollers 53 that feed the sheet P placed on the mounting section are installed so as to face the mounting surface, on the upper downstream side in the feeding direction and above the center in the width direction. In Modification 4, of the two curved plates 72, the curved plate 72 installed on the downstream side in the feeding direction (above Figure 21) has a horizontally formed portion (opposing surface) facing the feeding roller 53. In Modification 4, as described above, both of the two curved plates 72 have a horizontal surface formed in the center in the width direction. By configuring the feed rollers 53 to face the horizontal surface of the curved plate 72 with the sheet P in between, the gripping force of the feed rollers 53 against the sheet P is increased compared to when they are configured to face the curved surface, thus reducing the amount of misfeeding by the feed rollers 53. In addition, as an alternative form in Modification 4, as shown in Figure 22, a reinforcing plate 72x with higher rigidity than other parts can be provided on the horizontal portion of the curved plate 72 on the downstream side in the feeding direction that faces the feeding roller 53. With this configuration, even if the curvature of the curved plate 72 is changed by the variable means as described above, the horizontal portion is maintained in a horizontal state by the reinforcing plate 72x, thereby maintaining a high gripping force of the feeding roller 53 on the sheet P.

[0036] <Modification 5> As shown in Figures 23 and 24, the feeding device 70 installed in the image forming system 200 in Modified Example 5 differs from those shown in Figures 1 and 2 in that a conveying device 90 using a conveyor belt 91 is installed instead of a feeding mechanism 52, and a blower device 79 (second blower device) is installed separately from the blower device 76 (first blower device) installed on the side fence 75, which blows air onto the downstream end face in the feeding direction of the sheet P loaded on the curved plate 72. The conveying device 90 is positioned opposite the curved plate 72 (mounting section) on the downstream side in the feeding direction, and consists of a conveying belt 91 (conveying means) stretched and supported by two roller members (a drive roller 93 and a driven roller 92), and a suction device 95 (belt suction device). The blower 79 (second blower) is installed downstream of the sheet storage section 71 in the supply direction (to the left in Figures 22 and 23). The blower 79 blows air towards the uppermost sheet P placed on the curved plate 72 to make the sheet P float. The suction device 95 of the conveying device 90 is installed above the sheet storage section 71 and is for sucking up the uppermost sheet P that has been lifted by the blower 79. The conveying belt 91 then conveys the sheet P in the feeding direction while it is being held in place by the suction of the suction device 95 (which is the uppermost sheet P). Furthermore, a regulating plate 80 is installed on the upper part of the reference fence 73 (reference fence) in the sheet storage section 71. The regulating plate 80 is installed to stand upright from the reference fence 73 and restricts the movement in the feeding direction for the lower sheets P, other than the uppermost sheet P that is lifted by the second blower 79. Furthermore, even in the feeding device 70 configured as in Modification 5, the sheets P loaded on the curved plate 72 (mounting section) can be adequately handled by the first blower 76, making feeding failures less likely.

[0037] <Variation 6> As shown in Figure 25, in the modified example 6, the image forming apparatus 1 does not have the feeding device 70 with the curved plate 72 described above as an optional device that constitutes part of the image forming system 200, but rather the feeding device 70 with the curved plate 72 is built into the image forming apparatus 1 as part of the image forming apparatus 1. Furthermore, even in the feeding device 70 configured as in Modification 6, the sheets P loaded on the curved plate 72 (mounting section) can be adequately handled by the first blower 76, making feeding failures less likely.

[0038] As described above, the feeding device 70 in this embodiment is a feeding device for feeding sheets P in the feeding direction, and includes a liftable curved plate 72 (mounting section) having a mounting surface on which a plurality of sheets P can be loaded, and a blower 76 that blows air toward the end faces in the width direction perpendicular to the feeding direction of the plurality of sheets P loaded on the curved plate 72. The mounting surface of the curved plate 72 is curved in a convex shape upward from both ends in the width direction toward the center, either in whole or in part. This allows the sheets P loaded on the curved plate 72 (mounting section) to be handled efficiently, making feeding problems less likely.

[0039] 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, although the present invention was applied to a high-capacity feeding device 70 in the image forming apparatus 1 in this embodiment, the present invention can naturally also be applied to feeding devices that do not have a large capacity. Furthermore, even in such cases, the same effects as those of this embodiment can be obtained.

[0040] 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.

[0041] In this specification, the term "sheet" is defined to include all sheet-like recording media, such as coated paper, label paper, and OHP sheets, in addition to ordinary paper. [Explanation of symbols]

[0042] 1. Image forming apparatus (image forming apparatus main unit), 52 Feeding mechanism, 53 Feeding roller, 54 feed rollers, 55 Backup Laura, 62 Non-feed detection sensor, 63. Remaining amount detection sensor (detection means), 70 Feeding device (large capacity feeding device), 72 Curved plate (mounting part), 72x reinforcing plates, 74 End fence, 75 side fences, 75a Sheet retaining part, 76 Blower, 77 horizontal plate, 89 Regulating member (variable means), 115 Winding motor (variable means), 116 Winding member (variable means), 117 Wire (variable means), 200 image forming systems, P-seat.

[0043] Furthermore, the embodiments of the present invention can also be, for example, combinations of appendices 1 to 13 as follows. (Note 1) A feeding device that feeds sheets in the feeding direction, A liftable mounting section equipped with a mounting surface capable of accommodating multiple sheets, A blower that blows air toward the end faces in the width direction perpendicular to the feeding direction of the multiple sheets stacked on the mounting section, Equipped with, The feeding device is characterized in that the mounting surface of the mounting portion described above is curved in a convex shape upward from both ends in the width direction toward the center, in whole or in part. (Note 2) The mounting portion comprises an elastic curved plate on which all or part of the mounting surface described above is formed on its upper surface. The feeding device according to Appendix 1, characterized by comprising a variable means for varying the curvature of the curved plate. (Note 3) The feeding device according to Appendix 2, characterized in that the variable means varies the curvature of the curved plate according to at least one of the type, size, and thickness of the sheets loaded in the storage section described above. (Note 4) The feeding device according to Appendix 2 or Appendix 3, characterized in that the variable means varies the curvature of the curved plate according to the frequency of non-feeding of sheets fed from the feeding device. (Note 5) The feeding device according to any one of the appendices 2 to 4, characterized in that the variable means varies the curvature of the curved plate based on the detection result of a detection means for detecting the remaining number of sheets stacked in the storage section described above. (Note 6) The variable means is a pair or more of restricting members that vary the curvature of the curved plate, each having inclined surfaces that contact both ends in the width direction of the curved plate, which rises and falls according to the remaining number of sheets stacked in the aforementioned storage unit, The feeding device according to any one of the appendices 2 to 5, characterized in that the inclined surfaces of the pair or more pairs of regulating members are formed such that the distance between them gradually increases from bottom to top. (Note 7) The feeding device according to any one of the appendices 2 to 5, characterized in that the variable means comprises a wire connected to the corner of the curved plate and a winding member capable of winding the wire. (Note 8) The system is configured to allow the opposing distance in the width direction to be increased or decreased, and includes a pair of side fences that restrict the position of the sheet placed on the aforementioned mounting section in the width direction, The feeding device according to any one of the appendices 2 to 5, characterized in that the variable means varies the curvature of the curved plate in conjunction with an increase or decrease in the opposing distance between the pair of side fences. (Note 9) The aforementioned mounting section is Two curved plates are provided, divided to form the upstream and downstream sides in the feeding direction on the mounting surface, A horizontal plate forming the central part in the feeding direction on the mounting surface, A feeding device according to any one of the appendices 1 to 8, characterized by being equipped with the following: (Note 10) A feeding roller for feeding the sheet placed on the aforementioned mounting section is installed so as to face the aforementioned mounting surface, on the downstream side in the feeding direction and above the center in the width direction, The feeding device according to Appendix 9, characterized in that of the two curved plates, the curved plate installed on the downstream side in the feeding direction has a portion facing the feeding roller that is formed horizontally. (Note 11) The system is configured to allow the opposing distance in the width direction to be increased or decreased, and includes a pair of side fences that restrict the position of the sheet placed on the aforementioned mounting section in the width direction, The supply device according to any one of the appendices 1 to 10, characterized in that the blowing device is installed on each of the pair of side fences. (Note 12) An image forming apparatus characterized by being equipped with a feeding device described in any of the appendices 1 to 11. (Note 13) A feeding device described in any of the appendices 1 to 11, An image forming apparatus is provided, wherein the aforementioned feeding device is detachably installed, and an image is formed on a sheet fed from the feeding device, An image forming system characterized by comprising the following features. [Prior art documents] [Patent Documents]

[0044] [Patent Document 1] Japanese Patent Publication No. 2012-236709 [Patent Document 2] Japanese Patent Application Publication No. 9-309624

Claims

1. A feeding device that feeds sheets in the feeding direction, A liftable mounting section equipped with a mounting surface capable of accommodating multiple sheets, A blower that blows air toward the end faces in the width direction perpendicular to the feeding direction of the multiple sheets stacked on the mounting section, Equipped with, The feeding device is characterized in that the mounting surface of the mounting portion described above is curved in a convex shape upward from both ends in the width direction toward the center, in whole or in part.

2. The mounting portion comprises an elastic curved plate on which all or part of the mounting surface described above is formed on its upper surface. The feeding device according to claim 1, further comprising a variable means for varying the curvature of the curved plate.

3. The feeding device according to claim 2, characterized in that the variable means varies the curvature of the curved plate according to at least one of the type, size, and thickness of the sheets loaded in the storage section described above.

4. The feeding device according to claim 2, characterized in that the variable means varies the curvature of the curved plate according to the frequency of non-feeding of sheets fed from the feeding device.

5. The feeding device according to claim 2, characterized in that the variable means varies the curvature of the curved plate based on the detection result of a detection means for detecting the remaining number of sheets stacked in the storage section described above.

6. The variable means is a pair or more of restricting members that vary the curvature of the curved plate, each having inclined surfaces that contact both ends in the width direction of the curved plate, which rises and falls according to the remaining number of sheets stacked in the aforementioned storage unit, The feeding device according to claim 2, characterized in that the inclined surfaces of the pair or more pairs of regulating members are formed such that the distance between them gradually increases from bottom to top.

7. The feeding device according to claim 2, characterized in that the variable means comprises a wire connected to the corner of the curved plate and a winding member capable of winding the wire.

8. The system is configured to allow the opposing distance in the width direction to be increased or decreased, and includes a pair of side fences that restrict the position of the sheet placed on the aforementioned mounting section in the width direction, The feeding device according to claim 2, characterized in that the variable means varies the curvature of the curved plate in conjunction with an increase or decrease in the opposing distance between the pair of side fences.

9. The aforementioned mounting section is Two curved plates are provided, divided to form the upstream and downstream sides in the feeding direction on the mounting surface, A horizontal plate forming the central part in the feeding direction on the mounting surface, A feeding device according to claim 1 or 2, characterized by comprising the above.

10. A feeding roller for feeding the sheet placed on the aforementioned mounting section is installed so as to face the aforementioned mounting surface, on the downstream side in the feeding direction and above the center in the width direction, The feeding device according to claim 9, characterized in that of the two curved plates, the curved plate installed on the downstream side in the feeding direction has a portion facing the feeding roller formed horizontally.

11. The system is configured to allow the opposing distance in the width direction to be increased or decreased, and includes a pair of side fences that restrict the position of the sheet placed on the aforementioned mounting section in the width direction, The air blower is installed on each of the pair of side fences, as described in claim 1 or 2.

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

13. A feeding device according to claim 1 or claim 2, An image forming apparatus is provided, wherein the aforementioned feeding device is detachably installed, and an image is formed on a sheet fed from the feeding device, An image forming system characterized by comprising the following features.

Images