Sheet feeding device and image forming device

Abstract

To appropriately set the amount of air blown to sheets of different lengths in a sheet feeding direction.SOLUTION: An air sorting part has a blowing part, a first air outlet, and a second air outlet. The first air outlet is disposed at a position where air can be blown toward the sheets when the sheets supported by a support part are first sheets and second sheets with lengths in the feeding direction shorter than those of first sheets, and the second air outlet is disposed at a position where air can be blown toward the sheets when the sheets supported by the support part are the first sheets. When performing air sorting by the air sorting part (S1; YES), a control section sets the air volume of the blowing part to a first air volume when the sheets supported by the support part are the first sheets (S11), and sets the air volume of the blowing part to a second air volume larger than the first air volume when the sheets supported by the support part are the second sheets (S10).SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a sheet feeding device that feeds sheets and an image forming apparatus that uses the same. [Background technology]

[0002] In recent years, the colorization and high image quality of image forming devices such as copying machines, printers, and facsimiles using electrophotography have become widespread. In this type of image forming device, since there is a limit to obtaining the required beautiful and attractive finished product by forming an image on ordinary paper, special paper such as coated paper and thick paper is desired to obtain a more beautiful and attractive finished product. Conventionally, a manual feed device attached to the side wall of the image forming device has been used to feed special paper. The manual feed device can handle sheets of sizes that cannot be installed in the cassette feed device in the image forming device (long paper, irregular size, small size paper) and high-rigidity thick paper that cannot be fed unless the conveying path is straight because of the large conveying resistance. Here, coated paper is fed by placing only one sheet on the sheet tray of the manual feed device to prevent the sheets from sticking to each other, but this is poor productivity, so there has been a demand for improving productivity.

[0003] In response to this, a sheet feeding device has been developed that has an air handling device that blows air onto the side edges of sheets such as coated paper that stick to each other to handle the sheet stack, in a width direction that is approximately perpendicular to the sheet feeding direction (see Patent Document 1). This air handling device blows air onto the side edges of the sheet stack to allow air to enter between the sheets and break the adhesion between the sheets. This air handling device makes it possible to load multiple sheets of coated paper or the like onto the manual feed device and feed them continuously.

[0004] In order to use an air handling device to break the adhesion between sheets, it is necessary to blow an optimal amount of air. For this reason, an air handling device has been proposed that identifies the type and size of stacked sheets, determines whether sheets are being added, replaced, or removed, and measures the remaining amount of sheets to determine the optimal amount of air to be blown for sheet handling (see Patent Document 2). This air handling device uses an air volume determination table and an air volume adjustment table to determine the optimal amount of air to be blown for sheet handling, and in the case of adding or removing sheets, determines the optimal amount of air to be blown for sheet handling based on the amount of change in the remaining amount. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2006-256819 A [Patent Document 2] JP 2007-238239 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, the sheet feeding device described in Patent Document 2 does not disclose, for example, how the air volume should be changed for sheets with different lengths in the sheet feeding direction. Therefore, there is a risk that the sheets will be separated by blowing an air volume that is inappropriate for the length of the sheets. In this case, if the air volume is too large, the operating noise and power consumption will be excessive, and if the air volume is too small, the sheets may not be separated sufficiently.

[0007] An object of the present invention is to provide a sheet feeding device and an image forming apparatus that are capable of appropriately setting the amount of air blown for sheets having different lengths in the sheet feeding direction. [Means for solving the problem]

[0008] According to one aspect of the present invention, there is provided an air handling unit including a support portion that supports a sheet, a feeding portion that feeds the sheet supported by the support portion, a regulating portion that is movable in a width direction perpendicular to a feeding direction of the sheet supported by the support portion and that regulates a position of the sheet supported by the support portion in the width direction, an air blowing portion that blows air, a first air outlet that is disposed in the regulating portion and that blows the air blown from the air blowing portion in the width direction against the sheet supported by the support portion to handle the sheet, a second air outlet that is disposed in the regulating portion upstream of the first air outlet in the feeding direction and that blows the air blown from the air blowing portion in the width direction against the sheet supported by the support portion to handle the sheet, and a communication passage that communicates the air blowing portion, the first air outlet, and the second air outlet. and a control unit that controls the air blowing volume of the air blowing unit when performing air handling by the air handling unit, wherein the first air outlet is positioned at a position where it can blow air toward the sheets when the sheet supported on the support unit is a first sheet and a second sheet that is shorter in length in the feeding direction than the first sheet, and the second air outlet is positioned at a position where it can blow air toward the sheet when the sheet supported on the support unit is the first sheet, and the control unit, when performing air handling by the air handling unit, sets the air blowing volume of the air blowing unit to a first air volume when the sheet supported on the support unit is the first sheet, and sets the air blowing volume of the air blowing unit to a second air volume larger than the first air volume when the sheet supported on the support unit is the second sheet.

[0009] Another aspect of the present invention is an image forming apparatus including the above-mentioned sheet feeding device and an image forming section that forms an image on the sheet fed by the sheet feeding device. Effect of the Invention

[0010] According to the present invention, the amount of air blown can be appropriately set for sheets having different lengths in the sheet feeding direction. [Brief description of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view showing an image forming apparatus according to an embodiment. [Diagram 2] FIG. 2 is a block diagram showing a control system of the image forming apparatus according to the embodiment. [Diagram 3] 1 is a plan view showing a state in which A3 size sheets are stacked in a manual feeding section according to an embodiment. FIG. [Figure 4] 1 is a plan view showing a state in which A4 size sheets are stacked in a manual feed section according to an embodiment. FIG. [Diagram 5] 5 is a flowchart showing an operation procedure of a manual feed device of the image forming apparatus according to the embodiment. [Figure 6] 13 is a table for setting the airflow rate based on the basis weight and environmental conditions for each sheet size. (a) is for an A5 size sheet, (b) is for an A4 size sheet, and (c) is for an A3 size sheet. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The present embodiment will be described below with reference to the drawings. First, the schematic configuration of an image forming apparatus 1 according to this embodiment will be described with reference to Figs. 1 and 2. Fig. 1 is a cross-sectional view showing the schematic configuration of the image forming apparatus 1 according to this embodiment, and Fig. 2 is a block diagram of a control system. The image forming apparatus 1 is a tandem type intermediate transfer type laser beam printer that utilizes an electrophotographic process. The image forming apparatus 1 can form and output a full-color or monochrome image corresponding to print image data output from a host device 900 connected to a control unit 100 on a sheet S, which is a recording medium.

[0013] 2, the control unit 100 is a control means for controlling the overall operation of the image forming apparatus 1, and transmits and receives information to and from the host device 900 and the operation unit 730. The control unit 100 also performs signal processing and sequence control for various process devices. Here, the host device 900 is a personal computer, an image scanner, a facsimile, or the like.

[0014] The control unit 100 has a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), etc., and controls each part in the image forming apparatus 1. The CPU outputs an output signal to each electric component to operate the electric component at a desired timing and with a required amount of control based on the detection signal input from each sensor and the information stored in the ROM. Therefore, it is the CPU that actually controls the electric components. The ROM and RAM store information data required for controlling each part, and the CPU reads the information data stored in the ROM and writes it to the RAM. The control unit 100 controls the amount of air blown by the blower fans 72, 82 when performing air handling by the first air handling unit 74 and the second air handling unit 84 of the manual feed unit 500 described later.

[0015] As shown in Fig. 1, the image forming apparatus 1 has an apparatus main body 201A and an image forming section 201B that forms an image on a sheet S. An image reading device 202 that is installed substantially horizontally is provided above the apparatus main body 201A. A discharge space V for discharging sheets is formed between the image reading device 202 and the apparatus main body 201A. The image forming apparatus 1 has a cassette feeding section 230 and a manual feeding section 500.

[0016] The cassette feeding section 230 feeds the sheet S from a feeding cassette 5 which is a sheet storage means for storing the sheet S. The cassette feeding section 230 has a pickup roller 2 and a separation roller pair consisting of a feed roller 3 and a retard roller 4 for separating the sheet S sent out from the pickup roller 2.

[0017] The manual feed section 500 feeds the sheet S from a manual feed tray 10, which is an example of a support section that supports the sheet S. The manual feed section 500 is an example of a sheet feeding device, and has a pickup roller 502 similar to the cassette feed section 230. In this embodiment, the manual feed tray 10 is provided so as to be openable and closable by rotating relative to the device main body 201A, which is an example of a housing, and is displaceable between a closed position and an open position, and supports the sheet S in the open position. The device main body 201A is provided with a separation roller pair for separating the sheet S sent out from the pickup roller 502, and the separation roller pair is composed of a feed roller 503 and a retard roller 504.

[0018] The image forming section 201B forms an image on a sheet fed by the cassette feeding section 230 or the manual feeding section 500. The image forming section 201B is of a four-drum full-color type, and has a laser scanner 210 and four process cartridges 211 that form toner images of four colors, yellow (Y), magenta (M), cyan (C), and black (K). Here, each process cartridge 211 is equipped with a photosensitive drum 212, a charger 213 as a charging means, and a developer 214 as a developing means. The image forming section 201B also has a secondary transfer section 218 and a fixing section 201E disposed above the process cartridges 211. A toner cartridge 215 supplies toner to the developer 214.

[0019] The secondary transfer unit 218 includes a transfer belt 216 wound around a drive roller 216a and a tension roller 216b. A primary transfer roller 219 is provided on the inside of the transfer belt 216, which contacts the transfer belt 216 at a position facing the photosensitive drum 212. The transfer belt 216 is rotated in the direction of an arrow by a drive roller 216a driven by a drive unit (not shown). A secondary transfer roller 217 that transfers a color image formed on the transfer belt 216 to a sheet S is provided at a position facing the drive roller 216a of the secondary transfer unit 218.

[0020] A fixing section 201E is disposed above the secondary transfer roller 217, and a first discharge roller pair 225a, a second discharge roller pair 225b, and a double-sided reversing section 201F are disposed above the fixing section 201E. The double-sided reversing section 201F is provided with a reversing roller pair 222 that can rotate forward and backward, and a re-conveying path R that conveys the sheet S, on one side of which an image has been formed, back to the image forming section 201B. An operation section 730 that accepts operations from a user is provided on the upper portion of the image forming apparatus 1. A touch panel type having both a display function and an input function is adopted as the operation section 730.

[0021] Next, an image forming operation of the image forming apparatus 1 will be described. First, when the image forming apparatus 1 receives image data of an original to be printed, the image information is subjected to image processing, converted into an electric signal, and transmitted to a laser scanner 210 of the image forming unit 201B. In the image forming unit 201B, the surface of the photosensitive drum 212, the surface of which is uniformly charged to a predetermined polarity and potential by a charger 213, is sequentially exposed to a laser. As a result, electrostatic latent images of yellow, magenta, cyan, and black are sequentially formed on the photosensitive drum of each process cartridge 211, respectively.

[0022] Thereafter, the electrostatic latent images are developed and visualized with toner of each color, and the toner images of each color on each photosensitive drum are transferred in order onto the transfer belt 216 in a superimposed manner by a primary transfer bias applied to a primary transfer roller 219. As a result, a toner image is formed on the transfer belt 216.

[0023] In parallel with this toner image forming operation, the sheets S are conveyed one by one by the cassette feeding section 230 or the manual feeding section 500 to the registration roller pair 240, and skew is corrected by the registration roller pair 240. After the skew is corrected, the sheets S are conveyed by the registration roller pair 240 to the secondary transfer section 218, and the toner images are transferred all at once onto the sheets S by a secondary transfer bias applied to the secondary transfer roller 217 in the secondary transfer section 218.

[0024] Next, the sheet S onto which the toner image has been transferred is transported to the fixing section 201E, where the toners of the various colors melt and mix under heat and pressure in a roller nip section formed by the pressure roller 220a and the heating roller 220b, and are fixed as a color image on the sheet S. The sheet S onto which the image has been fixed is discharged into the discharge space V by a first discharge roller pair 225a or a second discharge roller pair 225b provided downstream of the fixing section 201E, and is stacked on a discharge tray 223 protruding from the bottom surface of the discharge space V. When images are formed on both sides of the sheet S, after the images are fixed, the sheet S is transported to a re-conveyance path R by a reversing roller pair 222, and is transported again to the image forming section 201B.

[0025] [Manual feed section] Next, the manual feed section 500 will be described with reference to Fig. 3 and Fig. 4. As shown in Fig. 3, the manual feed section 500 has a manual tray 10, a pickup roller 502, and a pair of a first side regulating section 70 and a second side regulating section 80.

[0026] The pickup roller 502 is an example of a feeding unit, and feeds the sheet S supported on the manual feed tray 10. In this embodiment, the pickup roller 502 that contacts the sheet and feeds it is used as the feeding unit, but the present invention is not limited to this, and for example, air feeding may be performed.

[0027] The manual feed section 500 is provided with a sheet presence sensor 21 and a size detection sensor 22 (see FIG. 2). The sheet presence sensor 21 is disposed, for example, downstream of the manual feed tray 10, and generates a signal when a sheet S is stacked on the manual feed tray 10 and transmits the signal to the control section 100, so that the control section 100 can detect that the sheet S has been placed regardless of the size. The size detection sensor 22 is disposed, for example, upstream of the sheet presence sensor 21 in the feeding direction FD. As a result, it detects an A3 size sheet shown in FIG. 3, generates a signal, and transmits the signal to the control section 100, but does not detect an A4 size sheet shown in FIG. 4 and does not generate a signal. Therefore, the control section 100 can identify whether the placed sheet S is A3 size or A4 size based on a combination of signals from the sheet presence sensor 21 and the size detection sensor 22.

[0028] The size detection sensor 22 is also disposed at a position where it can detect the position of the first side regulating portion 70 in the width direction W. This allows the size of the placed sheet in the width direction W to be detected. In this embodiment, the sheet presence / absence sensor 21 and the size detection sensor 22 are an example of a sheet detection unit 25. The sheet detection unit 25 detects the sheet S supported on the manual feed tray 10, and the detection result changes depending on whether the detected sheet S is an A3 size sheet or an A4 size sheet. In this embodiment, the A3 size sheet is called the first sheet, the A4 size sheet is called the second sheet, and the A5 size sheet is called the third sheet.

[0029] 2, the image forming apparatus 1 has an environment sensor 23 and a sheet type detection sensor 24. The environment sensor 23 is an example of an environment detection unit that detects environmental information, and in this embodiment, the environmental information is the temperature and humidity of the installation environment of the image forming apparatus 1. The sheet type detection sensor 24 is an example of a type acquisition unit, and is capable of acquiring the type of sheet by generating a signal that differs depending on the type (type according to material and thickness) of the sheet supported on the manual feed tray 10. This allows the control unit 100 to acquire the basis weight of the sheet supported on the manual feed tray 10.

[0030] In addition, in the present embodiment, the image forming apparatus 1 has the sheet detection unit 25, and thus the length of the sheet in the feeding direction FD can be automatically detected. However, the present embodiment is not limited to this. For example, the user may manually input the size to the operation unit 730. In addition, in the present embodiment, the image forming apparatus 1 has the environment sensor 23, and thus the environmental information can be automatically detected. However, the present embodiment is not limited to this. For example, the user may manually input the environmental information to the operation unit 730. In addition, in the present embodiment, the image forming apparatus 1 has the sheet type detection sensor 24, and thus the type of the sheet can be automatically detected. However, the present embodiment is not limited to this. For example, the user may manually input the type of the sheet to the operation unit 730. Even in this case, the control unit 100 can obtain the basis weight of the sheet supported by the manual feed tray 10.

[0031] [Side regulation part] The pair of first and second side regulating portions 70 and 80 are disposed on both sides of the sheet S in a width direction W intersecting with the feeding direction FD of the sheet S placed on the manual feed tray 10, and regulate the position of the sheet S in the width direction W. The first side regulating portion 70 is an example of a regulating portion, and is provided on the manual feed tray 10 so as to be movable in the width direction W, and regulates the position of the sheet S supported on the manual feed tray 10 in the width direction W. The second side regulating portion 80 is provided so as to be movable in the width direction W in conjunction with the first side regulating portion 70, and abuts against the other end of the sheet S placed on the manual feed tray 10 in the width direction W. In this embodiment, the width direction W is a direction perpendicular to the feeding direction FD of the sheet S.

[0032] The first side regulating portion 70 has a rack 71. Similarly, the second side regulating portion 80 has a rack 81. Each rack 71, 81 is meshed with a pinion gear 90 to be interlocked. As a result, at least one of the first side regulating portion 70 and the second side regulating portion 80 is movable in the width direction W, and in this embodiment, both the first side regulating portion 70 and the second side regulating portion 80 are movable in synchronization with the width direction W of the sheet S. Note that one of the first side regulating portion 70 and the second side regulating portion 80 may be fixed so as not to move. Also, only the first side regulating portion 70 may be provided movably, and the second side regulating portion 80 may not be provided.

[0033] The first side regulating section 70 is provided with a first air handling section 74 having a blower fan 72, which is an example of a blower section, a first outlet 73a, a second outlet 73b, and a communication passage 75. The blower fan 72 is rotated by an electric motor (not shown), and the rotation speed is controlled by the control section 100. The control section 100 increases the amount of blown air by increasing the rotation speed of the blower fan 72, and decreases the rotation speed of the blower fan 72 to decrease the amount of blown air. The communication passage 75 is a duct that communicates the blower fan 72 with the first outlet 73a and the second outlet 73b. The first outlet 73a is disposed in the first side regulating section 70, and blows air blown from the blower fan 72 in the width direction W against the sheets S supported by the manual feed tray 10 to handle the sheets S. The second air outlet 73b is disposed upstream of the first air outlet 73a in the feeding direction FD in the first side regulating section 70, and blows air blown from the blower fan 72 in the width direction W toward the sheets S supported on the manual feed tray 10 to separate the sheets S. In this manner, the air f1 is blown out from the first air outlet 73a and the second air outlet 73b by driving the blower fan 72, and is blown toward the side of the sheet stack placed on the manual feed tray 10. By blowing the air f1 from the blower fan 72 toward the side end of the sheets S as separating air, the sheets S above the sheet stack are lifted, and the adhesion force between the sheets is reduced.

[0034] Similarly, the second side regulating section 80 is provided with a second air handling section 84 having a blower fan 82, a first air outlet 83a, a second air outlet 83b, and a communication passage 85. The blower fan 82 is rotated by an electric motor (not shown), and the rotation speed is controlled by the control section 100. The control section 100 increases the amount of air blown by increasing the rotation speed of the blower fan 82, and decreases the rotation speed of the blower fan 82 to decrease the amount of air blown. The communication passage 85 is a duct that communicates the blower fan 82 with the first air outlet 83a and the second air outlet 83b. The first air outlet 83a is disposed in the second side regulating section 80, and blows the air blown from the blower fan 82 in the width direction W against the sheets S supported by the manual feed tray 10 to handle the sheets S. The second air outlet 83b is disposed upstream of the first air outlet 83a in the second side regulating section 80 in the feeding direction FD, and blows air blown from the blower fan 82 in the width direction W against the sheets S supported on the manual feed tray 10 to separate the sheets S. In this manner, the blower fan 82 is driven to blow air f2 from the first air outlet 83a and the second air outlet 83b, and blows the air against the side of the sheet stack placed on the manual feed tray 10 opposite the first side regulating section 70. By blowing the air f2 from the blower fan 82 toward the side end of the sheets S as separation air, in combination with the air f1 blown from the opposite side, the sheets S above the sheet stack are effectively lifted, and the adhesion force between the sheets is reduced.

[0035] When the user selects the manual feed unit 500 and executes an operation to start image formation, sheet feeding starts from the manual feed unit 500. If the sheet S placed on the manual feed tray 10 is, for example, coated paper, the blower fans 72 and 82 are operated. As a result, air f1 and f2 are blown to the ends of the sheet stack in the width direction W from the first blower outlet 73a, the second blower outlet 73b, the first blower outlet 83a, and the second blower outlet 83b.

[0036] A predetermined time after the blowing of air f1 and f2 starts, the uppermost sheet S, in which the adhesive force between the sheets has been reduced, is fed by a rotating pickup roller 502 and sent to a pair of separation rollers consisting of a feed roller 503 and a retard roller 504. The sheet S separated into one sheet by the pair of separation rollers is conveyed to the pair of registration rollers 240 by a pair of conveying rollers 506.

[0037] [Position of each air outlet] The positions of the first air outlet 73a and the second air outlet 73b will be described. FIG. 3 shows a state in which an A3-sized sheet S, which is a first sheet, is placed with the feeding direction FD as the longitudinal direction. The first air outlet 73a and the second air outlet 73b face the A3-sized sheet S in the width direction W and are arranged at positions where air can be blown toward the side ends of the sheet S. FIG. 4 shows a state in which an A4-sized sheet S, which is a second sheet, is placed with the feeding direction FD as the short side direction. The first air outlet 73a faces the A4-sized sheet S in the width direction W and is arranged at a position where air can be blown toward the side ends of the sheet S. In contrast, the second air outlet 73b does not face the sheet S in the width direction W, and the blown air is not blown toward the sheet S.

[0038] In this way, the manual feed section 500 having the first air handling section 74 and the second air handling section 84 shown in FIG. 3 has four air outlets, and when separating sheets, separating air is blown out from all four outlets. At this time, for the A3 size sheet S shown in FIG. 3, all four outlets blow air to the sheet end, and for the A4 size sheet S shown in FIG. 4, two outlets (first air outlets 73a, 83a) downstream in the feeding direction FD blow air to the sheet end. Therefore, in the case of A4 size, the number of outlets blowing separating air to the sheet end is reduced compared to the case of A3 size, and the effect of loosening the adhesive force of the sheet is reduced. Therefore, in this embodiment, the rotation speed of the blower fans 72, 82 is increased in the case of A4 size compared to the case of A3 size, so that the amount of separating air is increased and stable separating can be performed.

[0039] Furthermore, the adhesive force generated between sheets increases as the size of the sheets increases. Conversely, the force decreases as the sheet size becomes smaller. Therefore, for example, the suction force of an A5 size sheet is small, and the sheet can be conveyed without blowing the separating air. In this embodiment, when an A5 size sheet is placed on the manual feed tray 10, the A5 size sheet is placed as an A5R size sheet with the feeding direction FD as the longitudinal direction, as shown by the two-dot chain line in FIG. 4. At this time, the length of the A4 size sheet and the A5R size sheet in the feeding direction FD is the same, but the positions of the first side regulating unit 70 and the second side regulating unit 80 change, so that the control unit 100 can detect the sheet size from the detection result of the sheet detection unit 25.

[0040] [Air handling operation procedure] Next, the procedure of the air handling operation using the manual feed unit 500 will be described with reference to the flowchart shown in Fig. 5. First, the control unit 100 can select and execute a first mode in which air handling is performed by the first air handling unit 74 and the second air handling unit 84 to feed the sheet, and a second mode in which the sheet is fed without performing air handling. For example, the control unit 100 executes the first mode when feeding coated paper or waterproof paper with high adhesive power, since air handling is necessary, and executes the second mode when feeding other paper such as plain paper, since air handling is not necessary.

[0041] The control unit 100 receives a job and judges whether or not air separation is necessary when feeding a sheet from the manual feed unit 500 (step S1). When the control unit 100 judges that the type of sheet is plain paper or the like and air separation is not necessary (step S1; NO), the control unit 100 selects the second mode and executes sheet feeding without air separation (step S13), and ends the job.

[0042] When the control unit 100 determines that the type of sheet is coated paper or waterproof paper with high suction power and air handling is necessary (step S1; YES), it selects an air handling table to be used based on the basis weight of the sheet (step S2). Fig. 6(a) to (c) are examples of air handling tables, Fig. 6(a) is for a small size sheet such as A5 size, Fig. 6(b) is for a medium size sheet such as A4 size, and Fig. 6(c) is for a large size sheet such as A3 size. In each table, sheets A to C indicate different basis weights, with sheet A being a light weight sheet, sheet B being a medium weight sheet, and sheet C being a heavy weight sheet. In each table, the duty ratio indicates the air volume of the blower fans 72 and 82, with 100% indicating the maximum air volume and 0% indicating stop. For the duty ratio, linear interpolation or the like may be performed on the environmental information. For example, the control unit 100 selects sheet A on the table when the basis weight is light (step S3), selects sheet B on the table when the basis weight is medium (step S4), and selects sheet C on the table when the basis weight is heavy (step S5).

[0043] The determination based on the basis weight will be specifically described using a table. Then, the case of blowing air to an A4 size sheet will be described using the table shown in Fig. 6(b). The control unit 100 increases the airflow rate (60%) of the blower fans 72, 82 when the basis weight of the sheet is a second basis weight (164 to 220) larger than the first basis weight, compared to the airflow rate (40%) of the blower fans 72, 82 when the basis weight of the sheet is a first basis weight (to 163).

[0044] Next, the control unit 100 acquires environmental information of the installation environment (step S6). Here, for example, ranges are set in advance for each of three environmental patterns, H / H (high temperature / high humidity), N / N (medium temperature / medium humidity), and N / L (medium temperature / low humidity), and the information that fits the range is selected. Examples of each temperature and humidity are H / H (30°C / 80%), N / N (23.5°C / 50%), and N / L (23.5°C / 15%). The adhesive force between sheets also varies depending on the temperature and humidity, and the adhesive force in H / H is the largest compared to other environments. In N / L, the adhesive force is low and stable paper passing is possible without air handling. N / N is an environment between H / H and N / L, and although it does not have as much adhesive force as H / H, air handling is necessary because the sheets are adsorbed to each other.

[0045] Therefore, when the control unit 100 determines that the installation environment is H / H, it selects the H / H column in the table (step S7), and when the control unit 100 determines that the installation environment is N / N, it selects the N / N column in the table (step S8). As a result, the control unit 100 changes the airflow rate of the blower fans 72, 82 based on the detection result of the environment sensor 23. Note that when the control unit 100 determines that the installation environment is N / L, it determines that air clearance is not necessary, and executes sheet feeding without performing air clearance (step S13), and ends the job.

[0046] The judgment based on the environmental information will be specifically described using a table. Here, the medium humidity is 50% and the low humidity is 15%. The case where air is blown to an A3 size sheet will be described using the table shown in FIG. 6(c). In this case, the airflow rate (0%) of the blower fans 72, 82 when the detected humidity is a second humidity (15%) lower than the first humidity is set to be smaller than the airflow rate (40%) of the blower fans 72, 82 when the detected humidity is a first humidity (50%). Also, the case where air is blown to an A4 size sheet will be described using the table shown in FIG. 6(b). In this case, the airflow rate (0%) of the blower fans 72, 82 when the detected humidity is a second humidity (15%) lower than the first humidity is set to be smaller than the airflow rate (40% to 60%) of the blower fans 72, 82 when the detected humidity is the first humidity (50%).

[0047] Next, the control unit 100 judges the size of the sheet (step S9). The control unit 100 may actually identify the size of the sheet, but it is sufficient to detect the range of the length of the sheet in the feeding direction FD without identifying a specific size such as A4 or A3. If the control unit 100 judges that the sheet size is A4, it selects a table for medium size (FIG. 6(b)) (step S10). If the control unit 100 judges that the sheet size is A3, it selects a table for large size (FIG. 6(c)) (step S11). Then, among the selected tables, one of sheets A to C and one of rows H / H or N / N are set according to the result of the previous selection, and the output of the blower fans 72 and 82 is determined to perform air handling (step S12). From the above, it is possible to perform air handling with an appropriate air volume according to the sheet type, sheet size, and environmental conditions.

[0048] As a result, when the first air handling section 74 and the second air handling section 84 perform air handling, if the sheet supported by the manual feed tray 10 is A3 size, the control section 100 sets the air volume of the blower fans 72, 82 to the first air volume (80%). Then, when the first air handling section 74 and the second air handling section 84 perform air handling, if the sheet supported by the manual feed tray 10 is A4 size, the control section 100 sets the air volume of the blower fans 72, 82 to the second air volume (100%) which is larger than the first air volume. That is, the control section 100 switches the air volume of the blower fans 72, 82 to either the first air volume (80%) or the second air volume (100%) based on the detection result of the sheet detection section 25. In this embodiment, a case is described in which the first air volume is 80% and the second air volume is 100%, but this is not limited to this and other numerical values ​​may be used as long as the second air volume is greater than the first air volume.

[0049] Here, air is blown onto the sheet end to loosen the adhesion between the sheets, but for A5R size sheets, the adhesion force is not strong enough to require separation of the sheets by blowing air. In contrast, if air is blown at a volume inappropriate for the size and basis weight of the sheets to separate them, the operation noise and power consumption will be excessive if the air volume is large. Therefore, in step S9, when the control unit 100 determines that the size of the sheets is A5R size or A5 size, the adhesion force between the sheets is small, so the control unit 100 proceeds to the feeding operation without performing air separation (step S13). That is, when the sheet supported by the manual feed tray 10 is A5R size, which has the same length in the feeding direction FD as A4 size, is positioned opposite the first air outlet 73a, and is A5R size, which has a length in the width direction W shorter than A4 size, the control unit 100 stops blowing air from the blower fans 72 and 82.

[0050] As described above, according to the manual feed section 500 of this embodiment, when the sheet is A3 size, the airflow of the blower fans 72, 82 is set to the first airflow (80%), and when the sheet is A4 size, the airflow is set to the second airflow (100%), which is larger than the first airflow. Therefore, the airflow can be appropriately set for sheets having different lengths in the sheet feeding direction FD. As a result, the sheets can be separated by blowing air at an appropriate amount according to the length of the sheets, so that even the last sheet of the sheet stack placed on the manual feed tray 10 can be stably separated. In addition, it is possible to solve the problems of excessive operating noise and power consumption due to an excessive airflow, and insufficient sheet separation due to an excessive airflow.

[0051] Furthermore, according to the image forming apparatus 1 of the present embodiment, when the sheet size is determined to be A5R size or A5 size, the adhesive force between the sheets is small, so the apparatus proceeds to the feeding operation without performing air separation, thereby making it possible to suppress excessive operating noise and power consumption.

[0052] In the above-mentioned embodiment, specific values ​​are used in each part of the description, but the present invention is not limited to these values. For example, the adhesion between sheets depends on the type of media, ambient environmental conditions, etc., such as sheet size, dimensions, basis weight, and humidity, and may be determined according to each condition.

[0053] In the above embodiment, the sheet detection unit 25 is used to detect the length of the sheet in the feeding direction FD, but the present invention is not limited to this. For example, the user may input information to the operation unit 730. In this case, the operation unit 730 is an example of an input unit, and information regarding the length of the sheet in the feeding direction FD supported by the manual feed tray 10 is input. The information regarding the length in the feeding direction FD here may be the length itself, or may be a sheet size such as A3 or A4. In either case, the control unit 100 can make the determination in step S9 of FIG. 5 based on the input information. That is, the control unit 100 switches the airflow of the blower fans 72 and 82 to either the first airflow (80%) or the second airflow (100%) based on the information input to the operation unit 730. [Explanation of symbols]

[0054] 1...image forming apparatus, 10...manual feed tray (support section), 23...environment sensor (environment detection section), 24...sheet type detection sensor (type acquisition section), 25...sheet detection section, 70...first side regulating section (regulating section), 72...blower fan (blower section), 74...first air handling section (air handling section), 75...connection path, 201A...apparatus main body (housing), 201B...image forming section, 500...manual feed section (sheet feeding device), 502...pickup roller (feeding section), FD...feeding direction, S...sheet, W...width direction

Claims

1. A support portion that supports the seat; a feeding section that feeds the sheet supported by the supporting section; a regulating portion that is movable in a width direction perpendicular to a feeding direction of the sheet supported by the support portion and that regulates a position of the sheet supported by the support portion in the width direction; an air handling unit having an air blowing unit that blows air, a first air outlet that is disposed in the regulating unit and blows the air blown from the air blowing unit against the sheets supported by the support unit in the width direction to handle the sheets, a second air outlet that is disposed in the regulating unit upstream of the first air outlet in the feeding direction and blows the air blown from the air blowing unit against the sheets supported by the support unit in the width direction to handle the sheets, and a communication passage that communicates the air blowing unit, the first air outlet, and the second air outlet; A control unit that controls the air blowing amount of the blower when the air handling unit performs air handling, the first air outlet is disposed at a position where air can be blown toward the sheets when the sheets supported by the support portion are a first sheet and a second sheet having a length in the feeding direction shorter than that of the first sheet, the second air outlet is disposed at a position where air can be blown toward the seat when the seat supported by the support portion is the first seat, When the sheet supported on the support section is the first sheet, the control section sets the airflow rate of the air blowing section to a first airflow rate, and when the sheet supported on the support section is the second sheet, the control section sets the airflow rate of the air blowing section to a second airflow rate that is greater than the first airflow rate. A sheet feeding device comprising:

2. the control unit stops blowing air from the blowing unit when the sheet supported by the support unit is a third sheet that has the same length in the feeding direction as the second sheet, is positioned opposite the first blowing outlet, and has a length in the width direction shorter than that of the second sheet.

2. The sheet feeding apparatus according to claim 1, wherein the sheet feeding apparatus comprises:

3. The blower unit has a blower fan, The control unit increases the amount of air blown by increasing a rotation speed of the blower fan, and decreases the amount of air blown by decreasing the rotation speed of the blower fan.

2. The sheet feeding apparatus according to claim 1, wherein the sheet feeding apparatus comprises:

4. a sheet detection unit that detects a sheet supported by the support unit and whose detection result changes depending on whether the detected sheet is the first sheet or the second sheet; the control unit switches the airflow rate of the air blower unit to one of the first airflow rate and the second airflow rate based on a detection result of the sheet detection unit.

2. The sheet feeding apparatus according to claim 1, wherein the sheet feeding apparatus comprises:

5. the control unit switches the airflow rate of the air blower unit to one of the first airflow rate and the second airflow rate, based on information input to an input unit to which information regarding a length of the sheet in the feeding direction supported by the support unit is input.

2. The sheet feeding apparatus according to claim 1, wherein the sheet feeding apparatus comprises:

6. The control unit changes the airflow rate of the blower unit based on a detection result of an environment detection unit that detects environmental information.

2. The sheet feeding apparatus according to claim 1, wherein the sheet feeding apparatus comprises:

7. The environmental information is humidity, the control unit, when blowing air to the first sheet supported by the support unit, reduces the air blowing amount of the air blowing unit when the detected humidity is a second humidity lower than the first humidity, compared to the air blowing amount of the air blowing unit when the detected humidity is a first humidity.

7. The sheet feeding apparatus according to claim 6,

8. The environmental information is humidity, the control unit, when blowing air to the second sheet supported by the support unit, reduces the airflow rate of the air blower unit when the detected humidity is a second humidity lower than the first humidity, compared to the airflow rate of the air blower unit when the detected humidity is a first humidity.

7. The sheet feeding apparatus according to claim 6,

9. When blowing air to the second sheet supported on the support section, the control unit increases the air blowing volume of the air blowing unit when the basis weight of the sheet acquired by a type acquisition unit that acquires the type of the sheet supported on the support section is a second basis weight that is larger than the first basis weight, compared to the air blowing volume of the air blowing unit when the basis weight of the sheet acquired by the type acquisition unit that acquires the type of the sheet supported on the support section is a first basis weight.

2. The sheet feeding apparatus according to claim 1, wherein the sheet feeding apparatus comprises:

10. the support portion is provided so as to be openable and closable by rotating with respect to the housing, is displaceable between a closed position and an open position, and supports the seat in the open position.

2. The sheet feeding apparatus according to claim 1, wherein the sheet feeding apparatus comprises:

11. A sheet feeding device according to any one of claims 1 to 10, an image forming unit that forms an image on the sheet fed by the sheet feeding device, 1. An image forming apparatus comprising:

Images