Sheet feeding device and image forming apparatus

Abstract

To achieve both ease of sheet setting and separation performance with a simple configuration.SOLUTION: A sheet feeding device has: a stacking section; feeding means; a side end guide that is provided with a regulating surface; and air blowing means. The side end guide has: an air outlet that blows air from the air blowing means to an end in a sheet width direction of the sheets stacked on the stacking section; a first suppressing member that is movable between a protruding position protruding inward in the sheet width direction with respect to the regulating surface so as to suppress sheet lifting and a retreated position not protruding with respect to the regulating surface; and a second suppressing member that is disposed downstream of the first suppressing member in the feeding direction, and is fixed at a position protruding inward in the sheet width direction with respect to the regulating surface so as to suppress the sheet lifting.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a sheet feeding device that feeds sheets, and an image forming apparatus that forms images on sheets.

Background Art

[0002] In recent years, even in electrophotographic image forming apparatuses used in offices, there has been an increasing demand for high-quality, high-resolution output products using coated paper, thick paper and the like. However, for reasons such as high surface smoothness that makes coated paper and thick paper prone to adhesion between adjacent sheets, it is more difficult to separate and feed sheets one by one from a stacked sheet bundle compared to general plain paper and recycled paper for office use.

[0003] Patent Document 1 describes a technique that assists sheet separation by blowing air to the side edge of a sheet bundle set on a manual feed tray. Patent Document 2 describes a configuration for blowing air to the side edge of a sheet bundle, in which an upper end guide for restricting sheet floating is provided, and the upper end guide retracts from above the sheet bundle when air is not blown.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problem to be Solved by the Invention

[0005] To enhance the sheet separation effect by blowing air, it is desirable for air to spread widely into the gaps between the sheets. To achieve this, it is conceivable to distribute multiple restricting parts that regulate the lifting of the sheets. However, if multiple restricting parts are provided, the ease of setting the sheets may be impaired depending on the position of the restricting parts. Furthermore, if all of the multiple restricting parts are configured to be retractable like the upper end guide as described in the above-mentioned literature, the structure of the device becomes complex.

[0006] Therefore, the present invention aims to provide a configuration that is simple in design and can achieve both ease of sheet setting and separation performance. [Means for solving the problem]

[0007] One aspect of the present invention is a sheet feeding device comprising: a loading section on which sheets are loaded; a feeding means for feeding the sheets loaded in the loading section in a feeding direction; a side end guide having a regulating surface that faces the end of the sheet loaded in the loading section in the sheet width direction perpendicular to the feeding direction and regulates the sheet position in the sheet width direction; and a blowing means for supplying air to separate the sheets loaded in the loading section, wherein the side end guide has an outlet for blowing air from the blowing means onto the end of the sheet loaded in the sheet width direction, a protruding position that protrudes inward in the sheet width direction relative to the regulating surface to suppress the sheet from floating up, and a retracted position that does not protrude relative to the regulating surface. Between the air from the outlet A movable first restraining member and a second restraining member positioned downstream of the first restraining member in the feeding direction, Regardless of the air supply by the aforementioned blowing means, The sheet feeding device is characterized by having a second restraining member fixed to the regulating surface at a position that protrudes inward in the sheet width direction so as to suppress the sheet from lifting up. [Effects of the Invention]

[0008] According to the present invention, it is possible to achieve both ease of sheet setting and separation performance with a simple configuration. [Brief explanation of the drawing]

[0009] [Figure 1] A schematic diagram of an image forming apparatus according to one embodiment. [Figure 2] A view from above of a manual feeding unit according to one embodiment. [Figure 3] A view from above of a manual feeding unit according to one embodiment. [Figure 4] A diagram illustrating the arrangement of a retaining member according to one embodiment. [Figure 5] A perspective view showing the air outlet and upstream retaining member of a side end guide according to one embodiment. [Figure 6] Cross-sectional views (a, b) of a side end guide according to one embodiment. [Figure 7] A perspective view showing a downstream retaining member of a side end guide according to one embodiment. [Figure 8] Cross-sectional views (a, b) of a manual feeding unit according to one embodiment. [Modes for carrying out the invention]

[0010] The embodiments relating to this disclosure will be described below with reference to the drawings.

[0011] In this disclosure, "image forming apparatus" refers to an apparatus that forms an image on a sheet used as a recording material. Image forming apparatuses include printers, copiers, multifunction printers, commercial printing presses, and the like.

[0012] (Image forming apparatus) Figure 1 is a cross-sectional view showing the schematic configuration of an image forming apparatus 201 according to one embodiment. The image forming apparatus 201 is a tandem-type intermediate transfer laser beam printer utilizing an electrophotographic process. The image forming apparatus 201 can form and output full-color or monochrome images on a sheet S based on image data. A variety of sheets of different sizes and materials can be used as the sheet S, including paper such as plain paper and cardboard, plastic film, cloth, surface-treated sheet materials such as coated paper, and specially shaped sheet materials such as envelopes and index paper.

[0013] An image forming apparatus 201 includes: an apparatus main body 201A that accommodates an image forming section 201B; an image reading apparatus 300 that is arranged above the apparatus main body 201A and reads image information from a document; and a control section that controls the operation of the entire apparatus. The image forming section 201B, which is an example of an image forming means, includes four process units PY, PM, PC, PK, an exposure device 210, a transfer belt 216, and a fixing device 201E. A discharge space V for discharging sheets is formed between the image reading apparatus 202 and the apparatus main body 201A.

[0014] Each of the process units PY, PM, PC, PK includes a photosensitive drum 212 serving as an image carrier, and a charging device 213 serving as a process unit that acts on the photosensitive drum 212, a developing device 214, a cleaning device, and the like. The photosensitive drum 212 is an electrophotographic photosensitive member formed in a drum shape. The developing device 214 accommodates any one of yellow, magenta, cyan, and black toners as a developer. The exposure device 210 serving as a process means (exposure means) is arranged below the process units PY, PM, PC, PK.

[0015] The transfer belt 216 is an example of an intermediate transfer member. The transfer belt 216 is wound around a drive roller 216a and a tension roller 216b. Four primary transfer rollers 219 are arranged inside the transfer belt 216 at positions respectively opposing the photosensitive drums 212 with the transfer belt 216 interposed therebetween. The transfer belt 216 rotates counterclockwise in the drawing by the drive roller 216a driven by a drive unit (not shown). A secondary transfer roller 217 is arranged outside the transfer belt 216 at a position opposing the drive roller 216a with the transfer belt 216 interposed therebetween. A transfer section 201D (secondary transfer section) is formed as a nip portion between the secondary transfer roller 217 and the transfer belt 216.

[0016] A fixing device 201E is arranged above a transfer unit 201D. The fixing device 201E is of a heat fixing type, comprising a heating roller 220b heated by a heating means such as a halogen lamp, and a pressure roller 220a pressed against the heating roller 220b. Further above the fixing device 201E, a first discharge roller pair 225a, a second discharge roller pair 225b, and a double-sided reversing unit 201F are arranged. The double-sided reversing unit 201F includes a reversible reversing roller pair 222 and a re-conveyance path R.

[0017] An operation unit 730 that accepts operations from a user is provided at an upper portion of the image forming apparatus 201. The operation unit 730 includes a display device such as a liquid crystal panel that displays images, and an input device such as a numeric keypad and a print execution button. For example, the user can input setting information (type, basis weight, size, brand, etc.) of the sheet S set in the cassette feeding unit 230 and the manual feeding unit 235 via the operation unit 730.

[0018] A cassette feeding unit 230 is arranged at a lower portion of the apparatus main body 201A. A manual feeding unit 235 is arranged on a side surface of the apparatus main body 201A. The cassette feeding unit 230 and the manual feeding unit 235 are examples of a sheet feeding apparatus that feeds sheets.

[0019] The cassette feeding unit 230 includes a cassette 1 serving as a sheet storage means for storing sheets S, and a pickup roller 2 serving as a feeding means for feeding the sheets S from the cassette 1. Further, the cassette feeding unit 230 includes, as a separation and conveyance unit for separating the sheets P fed out from the pickup roller 2, a separation roller pair composed of a feed roller 3 and a retard roller 4. The retard roller 4 applies a frictional force in a direction opposite to the feeding direction to the sheets S at the nip portion between the retard roller 4 and the feed roller 3, thereby allowing only one sheet S in contact with the feed roller 3 to pass through the nip portion.

[0020] (Image Forming Operation) The control unit of the image forming apparatus 201 starts the image forming operation when it receives image data from an external source or when it receives a copy operation instruction and the image reading device 300 receives image data read from the original. In the image forming operation, each process unit PY, PM, PC, PK forms a toner image on the surface of the photosensitive drum 212 by an electrophotographic process. That is, when the process units PY, PM, PC, PK are requested to form a toner image, the photosensitive drum 212 is rotated, and the charging device 213 uniformly charges the surface of the photosensitive drum 212. The exposure device 210 irradiates the photosensitive drum 212 with laser light based on the image data received by the control unit from an external source or the image data read from the original by the image reading device 300. As a result, the surface of the photosensitive drum 212 is exposed and an electrostatic latent image is formed. The developing device 214 supplies a developer containing toner to the photosensitive drum 212 and develops the electrostatic latent image into a toner image.

[0021] The toner images formed by the process units PY, PM, PC, and PK are first transferred to the transfer belt 216 by the primary transfer roller 219. When forming a full-color image, the primary transfer is performed so that the toner images of each color overlap on the transfer belt 216, thereby forming a color image on the transfer belt 216. Any toner or other deposits remaining on the photosensitive drum 151 are removed by the cleaning devices of each process unit PY, PM, PC, and PK.

[0022] In parallel with the operation of the image forming unit 201B, the sheets S are fed one by one from the cassette feeding unit 230 or the manual feeding unit 235 and transported to the registration roller pair 240. After correcting the skew of the sheets S, the registration roller pair 240 transports the sheets S to the transfer unit 201D at a timing synchronized with the operation of the image forming unit 201B. Then, in the transfer unit 201D, the toner image is secondarily transferred from the transfer belt 216 to the sheets S by the secondary transfer roller 217 to which a transfer voltage is applied.

[0023] The sheet S, having passed through the transfer section 201D, is sent to the fixing device 201E. The fixing device 201E heats and pressurizes the toner image on the sheet S while transporting it by sandwiching it between the heating roller 220b and the pressure roller 220a. This results in an image fixed to the sheet S. Due to the adhesive force of the molten toner, a force is generated on the sheet S that causes it to stick to the heating roller 220b. If the rigidity of the sheet S is low (weak), there is a possibility that the sheet S will be wound up by the rotating heating roller 220b, so a separation plate 221 for separating the sheet is provided downstream of the heating roller 220b.

[0024] In the case of single-sided printing, the sheet S that has passed through the fuser 201E is discharged into the discharge space V by the first discharge roller pair 225a or the second discharge roller pair 225b and loaded onto the discharge tray 223. In the case of double-sided printing, the sheet S, which has an image formed on the first surface by passing through the transfer unit 201D and the fuser 201E, is inverted by the reversing roller pair 222 and transported again to the image forming unit 201B via the retransport path R. Then, the sheet S passes through the transfer unit 201D and the fuser 201E again to form an image on the second surface, and is then discharged into the discharge space V by the first discharge roller pair 225a or the second discharge roller pair 225b and loaded onto the discharge tray 223.

[0025] In the above description, the image forming unit 201B is an example of an image forming means, and a direct transfer type electrophotographic unit, or an inkjet type or offset printing type image forming unit may also be used.

[0026] (Manual feed unit) The manual feed unit 235, which has an air blowing section, will be explained with reference to Figure 2. Figure 2 is a view of the manual feed unit 235 from above. Unlike the cassette feed unit 230, which can store a large number of sheets, the manual feed unit 235 is configured to allow the user to set only the amount of sheets they need when using the image forming apparatus 201. Therefore, the cassette feed unit 230 is suitable for using plain paper and standard-sized sheets that are used frequently, while the manual feed unit 235 is suitable for using less frequently used sheets such as coated paper and long paper.

[0027] In the following description, "feeding direction Y" refers to the direction in which the sheet is fed out of the feeding tray 5 by the pickup roller 502. "Sheet width direction X" refers to the direction along the sheet loaded on the feeding tray 5, which is perpendicular to the feeding direction Y.

[0028] The manual feed unit 235 includes a feed tray 5, a pickup roller 502, a feed roller 503, a retard roller 504, side end guides 14a, 14b, and blower fans 15a, 15b.

[0029] The feed tray 5 is a loading section on which sheets are stacked. The feed tray 5 has a support surface 5a (mounting surface) that supports the lower surface of the sheets. The feed tray 5 is movable (openable and closable) between a position where it is stored in the side of the main body 201A of the image forming apparatus 201 and a position where it protrudes to the outside of the main body 201A. With the feed tray 5 open, the user can set a sheet in the feed tray 5. The feed tray 5 is also called a manual feed tray or a multi-purpose tray.

[0030] The pickup roller 502 is an example of a feeding means for feeding sheets. The pickup roller 502 is positioned above the support surface 5a of the feeding tray 5. The pickup roller 502 is rotatably supported by a roller holder 507, which acts as a holding member. The roller holder 507 is pivotable about the rotation axis of the feed roller 503. As the roller holder 507 pivots, the pickup roller 502 moves between a feeding position (contact position, lower position) where it contacts the upper surface of the sheets loaded on the feeding tray 5, and a standby position (separated position, upper position) where it is separated upward from the sheets. As the pickup roller 502 rotates in the feeding position, sheets are fed out of the feeding tray 5 in the feeding direction Y. Instead of the pickup roller 502, a mechanism may be used in which, for example, a negative pressure generated by a fan attracts sheets to a belt, and the sheets are transported by rotating the belt.

[0031] The feed roller 503 further transports the sheet received from the pickup roller 502 in the feeding direction Y. Downstream of the feed roller 503, a transport roller pair 506 is positioned to transport the sheet received from the feed roller 503 toward the registration roller pair 240 (Figure 1).

[0032] The retard roller 504 is pressed against the feed roller 503, forming a separation nip between them. The retard roller 504 is also driven by a torque limiter in the opposite direction to the rotation of the feed roller 503. The retard roller 504 is an example of a separation member that separates the sheet by frictional force, and may be a roller member connected to a fixed shaft via a torque limiter, or a pad-shaped elastic member that contacts the feed roller 503.

[0033] The side edge guides 14a and 14b are regulating members (regulating plates) that restrict the position of the sheet in the sheet width direction X. In this embodiment, a pair of side edge guides 14a and 14b facing each other in the sheet width direction X are used. The side edge guide 14b on the back side is an example of a second side edge guide that faces one of the side edge guides 14a. The side edge guides 14a and 14b have regulating surfaces 14a1 and 14b1 as their inner surfaces in the sheet width direction X. For one side edge guide, the "inside" in the sheet width direction X is the side on which the other side edge guide is positioned, and the "outside" in the sheet width direction X is the side opposite to the side on which the other side edge guide is positioned. The regulating surfaces 14a1 and 14b1 are surfaces that extend in the feeding direction Y and rise substantially perpendicular to the feeding tray 5 when viewed in the feeding direction Y. The restricting surfaces 14a1 and 14b1 contact the edges (side edges of the sheets) of the sheets loaded on the feeding tray 5 in the sheet width direction X, thereby restricting the position of the sheets in the sheet width direction X.

[0034] The side edge guides 14a and 14b are movable in the sheet width direction X relative to the feeding tray 5. The side edge guides 14a and 14b are connected by an interlocking mechanism such as a rack and pinion mechanism, and move in conjunction with each other so that their distance from the central position X0 in the sheet width direction X is equal. The central position X0 is the reference position in the sheet width direction X for the sheet fed by the manual feeding unit 235. Figure 2 shows the side edge guides 14a and 14b moved to their outermost position (the side edge position of the largest size sheet that can be fed from the manual feeding unit 235). Figure 3 shows the side edge guides 14a and 14b moved to their innermost position (the side edge position of the smallest size sheet that can be fed from the manual feeding unit 235).

[0035] One of the side edge guides 14a and 14b (the side edge guide 14a on the front side of the image forming apparatus 201) is provided with an operating knob for moving the side edge guides 14a and 14b. By moving the side edge guides 14a and 14b to a position that matches the size of the sheet being used, the user can prevent the sheet from becoming skewed or misaligned.

[0036] The blower fans 15a and 15b are examples of blower means that provide air to help separate the sheets loaded on the supply tray 5. The blower fans 15a and 15b generate airflow by taking in outside air from an air intake provided on the bottom surface of the supply tray 5, for example. In this embodiment, the blower fans 15a and 15b are positioned below the support surface 5a of the supply tray 5. The blower fans 15a and 15b are fan motors in which a fan body that generates airflow by rotation and a motor that drives the fan body are integrated.

[0037] In this embodiment, sirocco fans are used as blower fans 15a and 15b, but propeller fans (axial fans), for example, may be used as the blower. Also, the blower may be positioned above the support surface 5a of the supply tray 5.

[0038] The side end guides 14a and 14b have outlets 16a and 16b for blowing air from the blower fans 15a and 15b onto the side edges of the sheets on the supply tray 5. The outlets 16a and 16b are openings formed in the restricting surfaces 14a1 and 14b1 of the side end guides 14a and 14b. The outlets 16a and 16b are also connected to the exhaust sections of the blower fans 15a and 15b via ducts (air passages) formed inside the side end guides 14a and 14b.

[0039] When the blower fans 15a and 15b are activated, air is blown out from the outlets 16a and 16b toward the inside in the sheet width direction X, as shown by the streamlines A1 and A2.

[0040] The side end guides 14a and 14b further include upstream restraining members 17a and 17b and downstream restraining members 171a and 171b, which act as restraining members (floating restricting members) to prevent the sheet from lifting due to the blowing of air. These restraining members will be described later.

[0041] (Feeding operation of the manual feed unit) Next, the feeding operation in which the manual feed unit 235 feeds the sheets will be explained with reference to Figure 2. The user sets the sheets in the feeding tray 5 in advance and inputs the setting information of the set sheets via the operation unit 730.

[0042] When the user presses the print execution button, the blower fans 15a and 15b activate and begin blowing air, and air is blown from the outlets 16a and 16b onto the side edges of the sheets. This air enters the gaps between the sheets, causing them to float and reducing the adhesion between them. As a result, the manual feed unit 235 can feed the sheets one by one in a stable manner, even when using sheets with a highly smooth surface, such as coated paper, which are prone to sticking together. The control unit of the image forming apparatus 201 may also be configured to activate the blower fans 15a and 15b only when it determines, based on the sheet setting information, that separation by blowing air is necessary (for example, in the case of coated paper).

[0043] Subsequently, after a predetermined time has elapsed since the start of airflow from the blower fans 15a and 15b, the rotational drive of the pickup roller 502 and feed roller 503 is initiated, causing the roller holder 507 to swing and the pickup roller 502 to move from the standby position to the feeding position. Then, the uppermost sheet that has come into contact with the pickup roller 502 is sent to the feed roller 503, where it is separated from the other sheets at the separation nip and further transported, and then sent to the registration roller pair 240 (Figure 1) by the transport roller pair 506. The subsequent flow of sheet transport and image formation is as described above. In addition, the sheet transport timing is monitored by the sheet sensor 505 (Figure 1) detecting the sheet between the feed roller 503 and the transport roller pair 506.

[0044] (Arrangement of retaining members) Details of the air outlets 16a, 16b and retaining members (17a, 17b, 171a, 171b) provided on the side end guides 14a, 14b will be explained. First, the arrangement of the air outlets 16a, 16b and retaining members (17a, 17b, 171a, 171b) will be explained using Figure 4.

[0045] In this embodiment, two upstream restraining members 17a and one downstream restraining member 171a are arranged on the front side end guide 14a of the image forming apparatus 201. The two upstream restraining members 17a are spaced apart from each other in the feeding direction Y. The downstream restraining member 171a is spaced further downstream from the downstream upstream restraining member 17a in the feeding direction Y. Preferably, the downstream restraining member 171a is positioned in the downstream end region Ya of the regulating surface 14a1 in the feeding direction Y. Here, the downstream end region Ya in the feeding direction Y refers to the most downstream region when the total length of the regulating surface 14a1 in the feeding direction Y is divided into four equal parts.

[0046] The two upstream retaining members 17a are positioned at the two air outlets 16a provided on the side end guide 14a. In the illustrated example, the upstream retaining member 17a and air outlet 16a are positioned upstream of the central position Y0 of the regulating surface 14a1 in the supply direction Y, and the downstream retaining member 17a and air outlet 16a are positioned downstream of the central position Y0 of the regulating surface 14a1. However, the arrangement of the upstream retaining members 17a and downstream retaining members 171a is not limited to that shown. Furthermore, retaining members may be positioned at only a portion of the multiple air outlets 16a.

[0047] Similarly, two upstream retaining members 17b and one downstream retaining member 171b are arranged on the rear side end guide 14b. The two upstream retaining members 17b are spaced apart from each other in the feeding direction Y. The downstream retaining member 171b is spaced further downstream from the downstream upstream retaining member 17b in the feeding direction Y. The downstream retaining member 171b is preferably located in the downstream end region Ya of the regulating surface 14b1 in the feeding direction Y.

[0048] The two upstream retaining members 17b are positioned at the two outlets 16b provided on the side end guide 14b. In the illustrated example, the upstream retaining member 17b and outlet 16b are positioned upstream of the central position Y0 of the regulating surface 14b1 in the supply direction Y, and the downstream retaining member 17b and outlet 16b are positioned downstream of the central position Y0 of the regulating surface 14b1. However, the arrangement of the upstream retaining members 17b and downstream retaining members 171b is not limited to that shown. Furthermore, retaining members may be positioned at only some of the multiple outlets 16b.

[0049] The upstream retaining members 17a and 17b are movable between a protruding position, which protrudes inward in the sheet width direction X relative to the regulating surfaces 14a1 and 14b1 to suppress the lifting of the sheet, and a retracted position, which does not protrude relative to the regulating surfaces 14a1 and 14b1, as described below. It is preferable that the retracted position be set so that the entire upstream retaining members 17a and 17b are retracted outward from the regulating surfaces 14a1 and 14b1 with respect to the sheet width direction X. However, the inner surface of the upstream retaining members 17a and 17b in the sheet width direction X when located in the retracted position may be substantially flush with the regulating surfaces 14a1 and 14b1, except for slight errors such as manufacturing tolerances.

[0050] The downstream restraining members 17a and 17b are fixed in a position that protrudes inward in the sheet width direction X relative to the regulating surfaces 14a1 and 14b1. The downstream restraining members 17a and 17b can be molded as an integral part with the regulating surfaces 14a1 and 14b1 of the side end guides 14a and 14b.

[0051] Of the two upstream retaining members 17a, the downstream upstream retaining member 17a is an example of a first retaining member. The downstream retaining member 171a is an example of a second retaining member positioned downstream of the first retaining member in the feeding direction.

[0052] Similarly, the downstream of the two upstream retaining members 17b is an example of a first retaining member. The downstream retaining member 171b is an example of a second retaining member positioned downstream of the first retaining member in the feeding direction.

[0053] In this embodiment, the second outlets 16a and 16b are positioned upstream of the downstream outlets 16a and 16b in the supply direction Y, with a gap between them. In conjunction with this, the third upstream retaining members 17a and 17b are additionally positioned upstream of the downstream upstream retaining members 17a and 17b (first retaining members). This allows for more reliable control of the sheet lifting.

[0054] In this embodiment, the positions where the front upstream restraining member 17a and the outlet 16a are provided in the supply direction Y correspond to the positions where the two rear upstream restraining members 17b and the outlet 16b are provided in the supply direction Y. Furthermore, the position where the front downstream restraining member 171a is provided in the supply direction Y corresponds to the position where the rear downstream restraining member 171b is provided in the supply direction Y. As a result, the posture of the sheet can be made more stable in a configuration where wind is blown from both sides in the sheet width direction X.

[0055] (Air outlet and upstream retaining member) The air outlets 16a and 16b, and the movable upstream retaining members 17a and 17b positioned at the air outlets 16a and 16b will be described using Figures 5 and 6(a and b).

[0056] Figure 5 is a perspective view showing the outlet 16b and upstream retaining member 17b of the side end guide 14b. Figure 6(a) is a cross-sectional view of the side end guide 14b when the upstream retaining member 17a is in the retracted position, viewed from the downstream side in the supply direction Y. Figure 6(b) is a cross-sectional view of the side end guide 14b when the upstream retaining member 17a is in the protruding position, viewed from the downstream side in the supply direction Y.

[0057] As shown in Figure 5, the upstream retaining member 17b is positioned in the space inside the outlet 16b. The upstream retaining member 17b is rotatably supported by the side end guide 14b and rotates about the axis of the supply direction Y.

[0058] As shown in Figure 6(a), the upstream retaining member 17b is configured so that when it is in the retracted position, it does not protrude inward in the sheet width direction X relative to the restricting surface 14b1 of the side end guide 14b. Therefore, the upstream retaining member 17b is less likely to be an obstacle to setting and removing sheets from the feeding tray 5. In this embodiment, when the blower fan 15b is not blowing air, the upstream retaining member 17b remains in the retracted position due to its own weight.

[0059] As shown in Figure 6(b), when the upstream restraining member 17b is in the protruding position, it is configured to protrude inward in the sheet width direction X relative to the regulating surface 14b1 of the side end guide 14b. In this embodiment, when air (streamline B2) from the blower fan 15b is blown out from the outlet 16b, the wind pressure moves the upstream restraining member 17b from the retracted position to the protruding position.

[0060] Figures 5 and 6(a, b) illustrate the side edge guide 14b on the rear side, but the upstream retaining member 17b on the front side has substantially the same configuration, except that the positional relationship in the sheet width direction X is reversed.

[0061] When sheet S is lifted by the blowing of air, the upper surface of the uppermost sheet S comes into contact with the upstream restraining members 17a and 17b at the protruding position. The upstream restraining members 17a and 17b come into contact with the contact surfaces provided on the side end guides 14a and 14b, thereby restricting their rotation beyond the angle shown in Figure 6(b). As a result, the lifting height of the uppermost sheet S is restricted by the upstream restraining members 17a and 17b at the protruding position.

[0062] This reduces the possibility that the sheet S will float above the upper edge height of the air outlets 16a and 16b, thus preventing it from receiving the separation effect of the air spray. This allows the separation effect of the air spray to be more reliably achieved, reducing the possibility of double feeding.

[0063] Furthermore, the lower end height of the upstream restraining members 17a and 17b located in the retracted position (Figure 6(a)) is set higher than the maximum sheet loading height in the feeding tray 5. The maximum sheet loading height is indicated, for example, by attaching stickers indicating the maximum loading height to the regulating surfaces 14a1 and 14b1 of the side end guides 14a and 14b. This reduces the possibility that the sheets set in the feeding tray 5 may obstruct the rotation of the upstream restraining members 17a and 17b.

[0064] Furthermore, if the method of applying air blowing is changed depending on the type of sheet, the maximum stacking height for sheets that are subjected to air blowing (e.g., coated paper) may be set lower than the maximum stacking height for sheets that are not subjected to air blowing (e.g., plain paper). In addition, when coated paper is selected in the control unit 730, a message warning about the maximum stacking height may be displayed.

[0065] (Downstream restraining member) Figure 7 is a perspective view of the downstream retaining member 171b provided on the rear side edge guide 14b. Unlike the upstream retaining member 17b, the downstream retaining member 171b is fixed to the side edge guide 14b and always protrudes inward in the sheet width direction X relative to the regulating surface 14b1. The downstream retaining member 171a provided on the front side edge guide 14a has substantially the same configuration as the downstream retaining member 171b shown in Figure 7, except that the positional relationship in the sheet width direction X is reversed.

[0066] Since the downstream restraining members 171a and 171b are not movable like the upstream restraining members 17a and 17b, they have a simple structure and can be miniaturized.

[0067] When sheet S floats due to air blowing, the upper surface of the top sheet S comes into contact with the downstream retaining members 17a and 17b downstream in the supply direction Y from the upstream retaining members 17a and 17b, thereby restricting further floating. This prevents the edges of the sheets from lifting too much and allowing the air blown from the outlets 16a and 16b to spread widely into the gaps between the sheets. Therefore, the separation effect due to air blowing can be made more stable compared to a configuration without downstream retaining members 171a and 171b.

[0068] Furthermore, although the downstream retaining members 171a and 171b always protrude from the restricting surfaces 14a1 and 14b1 of the side end guides 14a and 14b, they are located downstream in the feeding direction Y from the upstream retaining members 17a and 17b, so they do not interfere with sheet setting or removal operations. In particular, since this embodiment is a manual feeding unit 235, the user usually sets the sheet by inserting it into the feeding tray 5 from the upstream side to the downstream side in the feeding direction Y. Therefore, the downstream retaining members 171a and 171b are even less likely to interfere with sheet setting operations.

[0069] Therefore, according to this embodiment, it is possible to achieve both ease of sheet setting and separation performance with a simple configuration.

[0070] Furthermore, if the corners at the leading edge of the sheet are significantly lifted by the blowing of air, there is a concern that the corners may collide with the transport guide or other components, potentially causing corner breakage or transport failure. In this embodiment, however, the lifting of the corners is restricted by the downstream restraining members 171a and 171b. This enables more stable sheet transport.

[0071] When the feeding tray 5 is viewed from above, the protruding area of ​​each upstream retaining member 17a, 17b relative to the regulating surfaces 14a1, 14b1 is larger than the protruding area of ​​the downstream retaining members 171a, 171b relative to the regulating surfaces 14a1, 14b1 (see Figure 4). The protruding area of ​​the upstream retaining members 17a, 17b is the area of ​​the portion of the upstream retaining members 17a, 17b located in the protruding position that protrudes inward in the sheet width direction X relative to the regulating surfaces 14a1, 14b1. The protruding area of ​​the downstream retaining members 171a, 171b is the area of ​​the portion of the downstream retaining members 171a, 171b that protrudes inward in the sheet width direction X relative to the regulating surfaces 14a1, 14b1. With the above configuration, the downstream retaining members 171a, 171b are less likely to interfere with sheet setting work, etc., while the upstream retaining members 17a, 17b can firmly suppress the lifting of the sheet near the center.

[0072] (Positional relationship when the tray is stored) The positional relationship between the downstream retaining members 171a and 171b and other members when the feeding tray 5 is stored in the main body 201A will be explained. Figure 8(a) is a cross-sectional view of the manual feeding section 235 with the feeding tray 5 open, cut by a virtual plane perpendicular to the sheet width direction X. Figure 8(b) is a cross-sectional view of the manual feeding section 235 with the feeding tray 5 closed, cut by a virtual plane perpendicular to the sheet width direction X.

[0073] As described above, the downstream retaining members 171a and 171b are provided on the side end guides 14a and 14b, which are movable in the sheet width direction X. Therefore, as shown in Figure 3, when the side end guides 14a and 14b are moved inward, the downstream retaining members 171a and 171b are located near the pickup roller 502 and the roller holder 507 that covers the pickup roller 502. When the feeding tray 5 is closed in this state, the downstream retaining members 171a and 171b move even closer to the pickup roller 502 and the roller holder 507.

[0074] However, unlike the upstream restraining members 17a and 17b, the downstream restraining members 171a and 171b of this embodiment are fixed to the side end guides 14a and 14b, making them smaller than the movable upstream restraining members 17a and 17b. Therefore, as shown in Figure 8(a), even when the feeding tray 5 is closed, the downstream restraining members 171a and 171b are housed in the space between the feeding tray 5 and the device body 201A without contacting the pickup roller 502 or the roller holder 507.

[0075] In particular, this embodiment employs a configuration in which the upstream retaining members 17a and 17b move due to the air pressure from the blower fans 15a and 15b. For this reason, as shown in Figures 4 and 6(a and b), the side end guides 14a and 14b require wall surfaces 14a2 and 14b2 that form ducts to guide air to the outlets 16a and 16b, located on the outside in the sheet width direction X relative to the upstream retaining members 17a and 17b.

[0076] In contrast, ducts are not required for the downstream retaining members 171a and 171b. Therefore, the thickness of the side end guides 14a and 14b in the sheet width direction X near the downstream retaining members 171a and 171b can be made smaller than the thickness of the side end guides 14a and 14b in the sheet width direction X near the upstream retaining members 17a and 17b. For example, in Figure 7, downstream of the downstream retaining member 171b in the feeding direction Y, the thickness of the side end guide 14b can be the thickness between the regulating surface 14b1 and its back surface 14b3.

[0077] Therefore, by designing the downstream restraining members 171a and 171b to be ductless, interference with components such as the pickup roller 502 is less likely to occur, and the degree of design freedom is improved.

[0078] As shown in Figure 3, the roller holder 507 has an inclined surface that slopes outward in the sheet width direction X toward the downstream direction Y. In this case, as shown in Figures 3 and 7, it is preferable that the end faces 171c of the downstream retaining members 171a and 171b are also inclined outward in the sheet width direction X toward the downstream direction Y. This reduces the likelihood of interference with members such as the roller holder 507 and improves design flexibility. Furthermore, as shown in Figure 7, if a part of the lower surface of the downstream retaining members 171a and 171b is inclined toward the upstream direction Y toward the feed tray 5, it is possible to reduce the snagging of the sheet when setting the sheet to be inserted from above in the feed direction Y.

[0079] (Other embodiments) In the embodiments described above, a mechanism that moves the retaining member by air pressure from a blowing means was illustrated as an example of a retaining member that can move between a protruding position and a retracted position. Alternatively, for example, the retaining member may be biased toward the protruding position by a spring member, so that when the sheet is set from above, the retaining member collapses to the retracted position, and when the sheet passes, the retaining member returns to the protruding position by the biasing force of the spring member. Even when such a retaining member is used as the upstream retaining member (first retaining member), the same advantages as in the embodiments described above can be obtained by making the downstream retaining member (second retaining member) fixed. In addition, for example, the upstream retaining member may be moved by an actuator such as a solenoid.

[0080] Furthermore, although the above-described embodiment illustrates a configuration in which a blower is attached to each of the pair of side end guides, a blower may be attached to only one of the side end guides. In this case, a retaining member to suppress the sheet from lifting may be placed only on the side where the sheet lifts due to the air from the blower. Alternatively, the blower may be fixed to the supply tray 5 or the main body of the device 201A, and air may be sent to the outlet of the side end guide via a duct that follows the movement of the side end guide.

[0081] Furthermore, the above-described embodiment mainly described a manual sheet feeder located on the side of an image forming apparatus used in an office. However, this technology is not limited to this, and may also be applied to a cassette feeder 230 (Figure 1). In addition, this technology may be applied to a manual sheet feeder or a sheet feeder (optional feeder) used in connection with the main body of a larger commercial image forming apparatus.

[0082] (Summary of this disclosure) This disclosure includes at least the following components:

[0083] (Composition 1) The loading section where the sheets are loaded, A feeding means for feeding the sheets loaded in the loading section in the feeding direction, A side end guide has a restricting surface that faces the end of the sheet loaded in the loading section in the sheet width direction perpendicular to the feeding direction and restricts the position of the sheet in the sheet width direction, A blowing means for supplying air to separate the sheets loaded in the loading section, A sheet feeding device having, The aforementioned side end guide is An air outlet that blows air from the aforementioned blowing means onto the edges of the sheets loaded in the loading section in the width direction of the sheets, A first restraining member is movable between a protruding position that protrudes inward in the width direction of the sheet relative to the regulating surface in order to suppress the lifting of the sheet, and a retracted position that does not protrude relative to the regulating surface. A second restraining member is positioned downstream of the first restraining member in the feeding direction, and is fixed in a position that protrudes inward in the sheet width direction relative to the regulating surface to suppress the sheet from lifting up, A sheet feeding device characterized by having the following features.

[0084] (Configuration 2) The aforementioned loading section is a manual feed tray provided on the side of the image forming apparatus. A sheet feeding device according to configuration 1, characterized by the above.

[0085] (Composition 3) The second retaining member is positioned so as not to come into contact with the feeding means when the tray is closed with the side end guide moved to its innermost position in the sheet width direction. The sheet feeding device according to configuration 2, characterized in that

[0086] (Composition 4) The system further comprises a holding member for holding the feeding means, The second retaining member is positioned so as not to come into contact with the holding member when the tray is closed with the side end guide moved to its innermost position in the sheet width direction. A sheet feeding device according to configuration 2 or 3, characterized by the above.

[0087] (Composition 5) The system further comprises a second side end guide that is opposite to the side end guide in the sheet width direction and moves in the sheet width direction in conjunction with the side end guide, The second side end guide has an outlet corresponding to the outlet, a retaining member corresponding to the first retaining member, and a retaining member corresponding to the second retaining member. A sheet feeding device according to any one of configurations 1 to 3, characterized by the above.

[0088] (Composition 6) The first restraining member moves from the retracted position to the protruding position due to the air pressure from the air blowing means, and remains in the retracted position due to its own weight when the air blowing means is not supplying air. A sheet feeding device according to any one of configurations 1 to 4, characterized by the above.

[0089] (Composition 7) At the position of the first restraining member in the aforementioned supply direction, a duct is provided on the outside of the restricting surface in the sheet width direction to guide air from the blowing means to the outlet. At the position of the second retaining member in the feeding direction, the duct is not provided on the outside of the restricting surface in the sheet width direction. The sheet feeding device according to configuration 6, characterized by the features described above.

[0090] (Composition 8) The second restraining member is located in the downstream end region of the regulating surface in the feeding direction, A sheet feeding device according to any one of configurations 1 to 7, characterized by the above.

[0091] (Composition 9) The system further includes a second outlet provided upstream of the outlet in the aforementioned supply direction, which blows air from the blowing means onto the sheet's widthwise end of the sheet loaded on the loading section, The side end guide further includes a third restraining member positioned upstream of the first restraining member in the feeding direction, The third restraining member is movable between a protruding position that protrudes inward in the sheet width direction relative to the regulating surface in order to suppress the sheet from lifting up, and a retracted position that does not protrude relative to the regulating surface. A sheet feeding device according to any one of configurations 1 to 8.

[0092] (Composition 10) The first restraining member is positioned downstream from the central position of the regulating surface in the feeding direction, The third restraining member is positioned upstream of the central position of the regulating surface in the feeding direction. The sheet feeding device according to configuration 9, characterized by the features described therein.

[0093] (Composition 11) When viewed from above the loading section, the area of ​​the portion of the first restraining member located at the protruding position that protrudes inward from the regulating surface in the sheet width direction is larger than the area of ​​the portion of the second restraining member that protrudes inward from the regulating surface in the sheet width direction. A sheet feeding device according to any one of configurations 1 to 10, characterized by the above.

[0094] (Composition 12) A sheet feeding device as described in any one of configurations 1 to 11, Image forming means for forming an image on a sheet fed from the sheet feeding device, An image forming apparatus characterized by comprising: [Explanation of Symbols]

[0095] 5…Loading section (feed tray) / 14a,14b…Side end guide / 14a1,14b1…Restricting surface / 15a,15b…Air blowing means (blower fan) / 16a,16b…Air outlet / 17a,17b…Upstream retaining member (first retaining member) / 171a,171b…Downstream retaining member (second retaining member) / 502…Feeding means (pickup roller)

Claims

1. The loading section where the sheets are loaded, A feeding means for feeding the sheets loaded in the loading section in the feeding direction, A side end guide has a restricting surface that faces the end of the sheet loaded in the loading section in the sheet width direction perpendicular to the feeding direction and restricts the position of the sheet in the sheet width direction, A blowing means for supplying air to separate the sheets loaded in the loading section, A sheet feeding device having, The aforementioned side end guide is An air outlet that blows air from the aforementioned blowing means onto the edges of the sheets loaded in the loading section in the width direction of the sheets, A first restraining member is movable by air from the outlet between a protruding position that protrudes inward in the width direction of the sheet relative to the regulating surface in order to suppress the sheet from lifting, and a retracted position that does not protrude relative to the regulating surface. A second restraining member is positioned downstream of the first restraining member in the supply direction, and is fixed in a position that protrudes inward in the sheet width direction relative to the regulating surface so as to suppress the sheet from lifting up regardless of the air supply by the air blowing means, A sheet feeding device characterized by having the following features.

2. The aforementioned loading section is a manual feed tray provided on the side of the image forming apparatus. The sheet feeding device according to feature 1.

3. The second retaining member is positioned so as not to come into contact with the feeding means when the tray is closed with the side end guide moved to its innermost position in the sheet width direction. The sheet feeding device according to feature 2.

4. The system further comprises a holding member for holding the feeding means, The second retaining member is positioned so as not to come into contact with the holding member when the tray is closed with the side end guide moved to its innermost position in the sheet width direction. The sheet feeding device according to feature 2.

5. The system further comprises a second side end guide that is opposite to the side end guide in the sheet width direction and moves in the sheet width direction in conjunction with the side end guide, The second side end guide has an outlet corresponding to the outlet, a retaining member corresponding to the first retaining member, and a retaining member corresponding to the second retaining member. The sheet feeding device according to feature 1.

6. The first restraining member moves from the retracted position to the protruding position due to the air pressure from the air blowing means, and remains in the retracted position due to its own weight when the air blowing means is not supplying air. The sheet feeding device according to feature 1.

7. At the position of the first restraining member in the aforementioned supply direction, a duct is provided on the outside of the restricting surface in the sheet width direction to guide air from the blowing means to the outlet. At the position of the second retaining member in the feeding direction, the duct is not provided on the outside of the restricting surface in the sheet width direction. The sheet feeding device according to feature 6.

8. The second restraining member is located in the downstream end region of the regulating surface in the feeding direction, The sheet feeding device according to feature 1.

9. The system further includes a second outlet provided upstream of the outlet in the aforementioned supply direction, which blows air from the blowing means onto the sheet's widthwise end of the sheet loaded on the loading section. The side end guide further includes a third restraining member positioned upstream of the first restraining member in the feeding direction, The third restraining member is movable between a protruding position that protrudes inward in the sheet width direction relative to the regulating surface in order to suppress the sheet from lifting up, and a retracted position that does not protrude relative to the regulating surface. The sheet feeding device according to feature 1.

10. The first restraining member is positioned downstream from the central position of the regulating surface in the feeding direction, The third retaining member is positioned upstream of the central position of the regulating surface in the feeding direction. The sheet feeding device according to feature 9.

11. When viewed from above the loading section, the area of ​​the portion of the first restraining member located at the protruding position that protrudes inward from the regulating surface in the sheet width direction is larger than the area of ​​the portion of the second restraining member that protrudes inward from the regulating surface in the sheet width direction. The sheet feeding device according to feature 1.

12. A sheet feeding device according to any one of claims 1 to 11, Image forming means for forming an image on a sheet fed from the sheet feeding device, An image forming apparatus characterized by comprising:

Images