Paper feeder

Abstract

To provide a paper feeder which prevents sheet feeding failure from occurring due to louvers in an air blowing mechanism.SOLUTION: A paper feeder 5 includes: a paper feeding mechanism 30 configured to feed a sheet on a loading tray 22; air blowing mechanisms 40, 50 having louvers 44, 45 for changing air blowing ranges at air outlets 41b, 51b. The louvers 44, 45 of the air blowing mechanisms 40, 50 are stopped at opening positions PB to open the air outlets 41b, 51b before the paper feeding mechanism 30 starts sheet feeding operation for at least a final sheet on the loading tray 22.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a sheet feeding device provided with a blower that blows air to the sides of sheets stacked in a storage compartment. [Background technology]

[0002] 2. Description of the Related Art Conventionally, image forming apparatuses such as printers and copying machines are provided with a sheet feeding device that separates sheets stacked on a stacking tray one by one and supplies the sheets to the image forming apparatus.

[0003] The paper feed device is provided with a stacking tray that can be raised and lowered and on which sheets are stacked, a feed roller that contacts the upper surface of the sheet to feed it, a separation mechanism that separates the fed sheets into single sheets and feeds them, and a pair of conveying rollers that convey the separated sheets toward the image forming device.The sheets on the liftable tray are guided along the paper feed path to the image forming device by the feed roller, separation mechanism, and pair of conveying rollers.

[0004] Such a paper feeder is provided with a detection means for detecting paper feed failures such as sheet jams, non-feeds, etc. A known detection means for this detection means is one that starts counting a timer when the feed roller is started, and determines whether a paper feed failure such as a sheet jam or non-feed has occurred based on whether a detection sensor provided between the separation mechanism and the pair of conveying rollers detects the leading edge of the sheet within a set count value.

[0005] There is also a machine equipped with a blower mechanism that blows air onto the sides of sheets stacked on a stacking tray (see, for example, Patent Document 1). This blower mechanism includes a duct having an intake port and an outlet port, a blower fan disposed within the duct, and a movable member attached to the outlet port of the duct. The outlet port of the duct is positioned to blow air onto the upper portions of the sheets stacked on the stacking tray. Specifically, the outlet port is disposed so that the sheet feed position for feeding the sheets is approximately centered vertically of the outlet port. The blower fan rotates to suck air from the intake port of the duct and blow it through the outlet port onto the sides of the sheets stacked on the stacking tray. Air is then blown from the outlet port onto the upper side surfaces of the stacked sheets, inserting air between the sheets to facilitate separation of the sheets when they are fed out. The movable member is configured to reciprocate at a constant interval between an open position that opens the outlet port and a closed position that closes the outlet port. The movable member moves upward from the open position to the closed position, gradually closing the air outlet from below, and moves downward from the closed position to the open position, gradually opening the air outlet from above. By moving the movable member back and forth in this way to change the open range of the air outlet, the strength of the air pressure blown onto the edge of the sheets varies, and the air is blown intermittently. This prevents sheet flapping and sheets from forming a bundle and being blown upward, improving separation accuracy and reducing sheet feeding problems. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2022-103483 Summary of the Invention [Problem to be solved by the invention]

[0007] In recent years, there has been a demand for such paper feeders to accommodate special sheets such as envelopes, labels, and magnetic sheets. Among these special sheets, magnetic sheets are characterized by their heavy weight, low rigidity, and flexibility. Therefore, when feeding the last magnetic sheet on a stacking tray, the sheet gets caught on the notches or uneven edges of the stacking tray, increasing the transport load. Therefore, when the last magnetic sheet on the stacking tray is lifted from the stacking tray by the air blowing mechanism, the transport load is reduced and the sheet is easily fed out. At this time, the last magnetic sheet lifts up when the opening range of the air outlet caused by the moving member is within the range where air is blown onto the stacking tray and the last magnetic sheet, but not elsewhere. In other words, when the moving member is positioned lower than the position of the stacking tray that positions the last magnetic sheet in the feed position, the air outlet portion facing the stacking tray and the edge of the last magnetic sheet is open, so air is blown onto the stacking tray and the last magnetic sheet, lifting the last magnetic sheet. However, when the moving member is located above the last magnetic sheet positioned in the paper feed position, the blowing portion facing the stacking tray and the end of the last magnetic sheet is closed, so air is not blown onto the stacking tray and the last magnetic sheet, and the last magnetic sheet does not float up. If the timer for determining paper feed problems such as sheet jams or non-feeding is activated (started) when the magnetic sheet has not floated up, it takes time for the magnetic sheet to move from a non-floating state to a floating state, so the timer count value exceeds the set value, causing the problem of frequent paper feed operation stoppages due to non-feeding.

[0008] SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to prevent sheet feeding failures caused by moving members. [Means for solving the problem]

[0009] In order to achieve the above object, the paper feeding device of the present invention comprises a loading tray on which sheets are loaded, a blowing means having a movable member that moves back and forth in the vertical direction to change the air blowing range at the air outlet, and blowing air from the air outlet to the ends of the sheets on the loading tray, and a paper feeding means that feeds the sheets on the loading tray, and the moving member stops at a predetermined position where air is blown to the last sheet on the loading tray before the paper feeding operation by the paper feeding means begins. [Effects of the Invention]

[0010] The above-described configuration can prevent non-feeding caused by the position of the moving member. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view showing an example of an image forming system including a paper feeder according to the present invention. [Figure 2] FIG. 2 is a conceptual diagram illustrating a configuration of a paper feed device. [Figure 3] FIG. 2 is a perspective view showing a blower mechanism of the paper feeder; [Figure 4] FIG. 2 is a block diagram showing a control system configuration of the paper feeder. [Figure 5] FIG. 4 is a flowchart showing a paper feeding operation in the paper feeding device. [Figure 6] FIG. 1 is a flowchart showing a paper feed process 1 in a paper feed operation. [Figure 7] FIG. 10 is a flowchart showing a paper feed process 2 in the paper feed operation. [Figure 8] 10A and 10B are diagrams illustrating states of the stacking tray and the louvers during a paper feeding operation. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Fig. 1 is a cross-sectional view showing an example of an image forming system including a paper feeder. The image forming system 1 is composed of a document feeder 4 that feeds documents, a document reader 3 that reads the documents fed by the document feeder 4, an image forming device 2 that prints the image of the document read by the document reader 3 on a sheet, and a paper feeder 5 connected to the image forming device 2. The image forming device 2 forms an image in an image forming unit 7 on a sheet supplied from either an upper cassette 10, a lower cassette 11, or the paper feeder 5 based on image data read from the document image by the document reader 3, and collects the image-formed sheets in a collecting unit 8.

[0013] The image forming unit 7 includes a charger 7a, a light projector (such as a laser head) 7b, a photosensitive drum 7c, a developing unit 7d, a transfer charger 7e, and a fixing roller 7f. An electrostatic latent image (still image) is formed by the light projector 7b on the surface of the photosensitive drum 7c, which has been charged by the charger 7a, and toner is then applied to the electrostatic latent image by the developing unit 7d. The toner applied to the photosensitive drum 7c is then transferred by the transfer charger 7e onto a sheet supplied from either the upper or lower cassette 10, 11 or the paper feeder 5. The sheet onto which the toner has been transferred is sent to the fixing roller 7f, which is located downstream, where the toner on the sheet is heated and fixed, and then the sheet is discharged to the stacking unit 8 by a pair of paper discharge rollers 9.

[0014] The upper and lower cassettes 10 and 11 are provided with paper feed mechanisms 10a and 10b, respectively, that feed the sheets stored in the cassettes 10 and 11. The sheets stored in the cassettes 10 and 11 are separated into individual sheets by the paper feed mechanisms 10a and 10b and sent to a conveying path 12. The sheets sent from the paper feed mechanisms 10a and 10b to the conveying path 12 are then sent to the image forming unit 7 via the conveying path 12.

[0015] The document reading device 3 is provided with a photoelectric conversion element 3a for converting received light into an electrical signal to generate image data, an optical system unit 3b for irradiating a document with light and guiding reflected light from the document to the photoelectric conversion element 3a, a reading glass 3c for reading a document transported by the document transport device 4, and a contact glass 3d on which the document to be read is placed. The document reading device 3 is capable of reading documents transported by the document transport device 4 and documents placed on the contact glass 3d by the optical system unit 3b and the photoelectric conversion element 3a, and the read image data is transferred to the image forming device 2.

[0016] Fig. 2 is a conceptual diagram showing the configuration of the paper feeder 5, and Fig. 3 is a perspective view showing an air blowing mechanism provided in the paper feeder 5. The sheets handled by the image forming apparatus 2 and the paper feeder 5 include plain paper, as well as overhead projector sheets, tracing paper, coated paper, etc., and are also capable of handling a variety of sheet sizes.

[0017] 1, slide rails 21a and 21b are provided on both the left and right sides of storage case 20. Storage case 20 is supported by housing 50 so as to be able to be pulled out via slide rails 21a and 21b. Feeding mechanism 30 includes a delivery roller 31, a feed roller 32, and a separation roller 33, which are driven by a sheet feed motor MT1. Sheets stored in storage case 20 are delivered by delivery roller 31, and separated and fed one by one by feed roller 32 and separation roller 33. Further, downstream of feeding mechanism 30 in the sheet feeding direction, a pair of conveying rollers 34a and 34b driven by a conveying motor MT2 are provided, and sheets fed by this pair of conveying rollers 34a and 34b are supplied to image forming device 2.

[0018] A stacking tray 22 that can be raised and lowered is provided inside the storage cabinet 20. The stacking tray 22 is formed of a flat plate on which a plurality of sheets can be stacked. The stacking tray 22 has notches for movement of a pair of side regulating plates 23 and 24 (described later) and a notch for movement of a rear end regulating plate 25.

[0019] An upper surface detection sensor S1 is provided above the storage case 20 to detect the position of the uppermost surface of the sheets stacked on the stacking tray 22 and position the uppermost sheet at the sheet feed position. A lower limit detection sensor S2 is provided below the storage case 20. The stacking tray 22 is configured to be able to be raised and lowered by an elevating mechanism 28 between the sheet feed position, which is raised a predetermined amount after being detected by the upper surface detection sensor S1, and the position detected by the lower limit detection sensor S2.

[0020] The lifting mechanism 28 includes a wire 26 attached to the stacking tray 22, a take-up pulley 27 that takes up the wire 26, a lifting motor MT3 that rotates the take-up pulley 27 in one direction to take up the wire 26, thereby lifting the stacking tray 22, and a drive transmission means (not shown) that transmits the drive of the lifting motor MT3 to the take-up pulley 27. The drive transmission means is configured by combining transmission members such as drive gears and timing belts.

[0021] A slit plate 29a of an encoder 29 for detecting the remaining number of sheets on the stacking tray 22 is attached to the shaft of the lifting motor MT3 or the rotation axis of the drive transmission gear. The encoder 29 detects the slits of the slit plate 29a, which rotates in synchronization with the lifting motor MT3, with an optical sensor 29b to generate a pulse signal. The position of the stacking tray 22 is identified by counting the number of pulses in the generated pulse signal, and the remaining number of sheets is detected from the position of the stacking tray 22.

[0022] A pair of side regulating plates 23, 24 are provided inside the storage cabinet 20 to align the sheets in a width direction perpendicular to the sheet feed direction. The pair of side regulating plates 23, 24 are configured to be movable in the sheet width direction to match the size of the sheets inside the storage cabinet 20. A trailing edge regulating plate 25 is also provided, which moves in the sheet feed direction to align the trailing edge of the sheet in the sheet feed direction. Note that in Figures 1 and 2, only the first side regulating plate 23 arranged on one end side in the sheet width direction is shown, and the second side regulating plate 23 is not shown.

[0023] 2 and 3, a first air blowing mechanism 40 as a first air blowing means disposed downstream in the sheet feed direction and a second air blowing mechanism 50 as a second air blowing means disposed upstream in the sheet transport direction are provided on the rear side of the sheet restricting surface of the first side restricting plate 23. The first and second air blowing mechanisms 40, 50 blow air from their respective air outlets (air outlets) 41b, 51b onto the sides of the sheets stacked on the stacking tray 22, lifting the sheets and allowing the air to penetrate between the sheets, thereby separating the sheets. The first side restricting plate 23, the first air blowing mechanism 40, and the second air blowing mechanism 50 are integrated into a unit, and are configured so that the first air blowing mechanism 40 and the second air blowing mechanism 50 also move as the first side restricting plate 23 moves.

[0024] The first blowing mechanism 40 includes a first duct (air passage) 41 having an intake port 41a and an outlet (air outlet) 41b, and a first blower fan 42 disposed within the first duct 41. The outlet 41b of the first duct 41 is connected to a first outlet opening 23a provided in the first side regulating plate 23 and is positioned to blow air onto the upper portions of the sheets stacked on the stacking tray 53. The blower fan 42 disposed within the first duct 41 rotates to suck air from the intake port 41a of the first duct 41 and blow it from the outlet 41b onto the sides of the sheets stacked on the stacking tray 22. In this embodiment, blowers (sirocco fans) that are also suitable for blowing air using a duct are used as the first blower fan 42 and a second blower fan 52 (described later).

[0025] A first louver 44 is provided on the side of the air outlet 41b in the first duct 41 of the first blowing mechanism 40 as a movable member for changing the range and direction of air blown out from the air outlet 41b. The first louver 44 is configured to rotate about a rotation shaft 44a at one end on the far side of the first duct 41 and a rotation shaft 46 at the other end. The first louver 44 moves to an open position PB (see the position of the first louver 44 indicated by the solid line in FIG. 8(a)) where the air outlet 41b is fully opened so that air can be blown toward the edge of the sheets on the stacking tray 22, and a blocked position PA (see the position of the first louver 44 indicated by the dashed line in FIG. 8(a)) where the part of the air outlet 41b facing the edge of the sheets is blocked so that the air is not blown toward the edge of the sheets. The first louvers 44 are controlled to swing up and down at a constant interval when blowing air to separate sheets. The opening width of the air outlet gradually narrows as the first louvers 44 rise from the open position PB toward the blocking position PA, and gradually widens as they descend from the blocking position PA toward the open position PB. In other words, swinging the first louvers 44 periodically increases and decreases the vertical width of the opening of the air outlet 41b. This changes the range of the air blown onto the edge of the sheets, varying the strength of the air pressure, and also changes the direction of the air, improving the accuracy of separating sheets.

[0026] The second blower mechanism 50 is disposed upstream of the first blower mechanism 40 and includes a second duct 51 having an intake port 51a and an outlet (air outlet) 51b, and a second blower fan 52 disposed within the second duct 51. The second duct 51 is disposed such that its outlet 51b is at the same height as the outlet 41b of the first duct 41. The outlet 51b of the second duct 51 is connected to a second outlet opening 23b provided in the first side regulating plate 23 and is positioned to blow air onto the upper upstream side of the sheets stacked on the stacking tray 22. The second blower fan 52 also sucks air from the intake port 51a of the second duct 51 and blows it from the outlet 51b onto the side of the sheets stacked on the stacking tray 22.

[0027] The second blower mechanism 50 is also provided with a louver 45 as a movable member. The second louver 45 provided in the second blower mechanism 50 is configured to rotate about a rotary shaft 45a at one end on the far side of the second duct 51 and a rotary shaft 46 at the other end. When blowing air to separate sheets, this louver 45 is controlled to swing up and down at a constant interval in synchronization with the first louver 44 of the first blower mechanism 40. In other words, like the first louver 44 of the first blower mechanism 40, the second louver 45 also periodically increases and decreases the vertical width of the opening of the air outlet 51b, thereby changing the blowing range of the air blown onto the edge of the sheets, thereby varying the strength of the air pressure and changing the direction of the air.

[0028] 3, the first and second louvers 44, 45 are supported on a common rotary shaft 46. This rotary shaft 46 is provided with a plurality of drive gears RZ that are drivingly connected to a louver motor MT6, and the first and second louvers 44, 45 reciprocate (stroke) up and down as the louver motor MT6 is driven forward and backward. In addition, a detection flag FG is provided on the rotary shaft 46, and this detection flag is provided at a position corresponding to the home position (HP) of the first and second louvers 44, 45. When the detection flag FG is detected by a louver detection sensor S4, it is determined that the first and second louvers 44, 45 are at the home position (HP). In this embodiment, as shown in Figure 8(a), the home position of the first and second louvers 44, 45 is the lowest position of the stroke range of the first and second louvers 44, 45, i.e., the open position PB where each air outlet 41b, 51b is fully open.

[0029] Fig. 4 is a control system block diagram of the sheet feeding device 5 shown in Fig. 2. As shown in Fig. 5, the sheet feeding device 5 is equipped with a control unit 100 having a CPU, a ROM storing programs for executing various processes, and a RAM for temporarily storing data. The control unit 100 also has an internal timer TM for time management and a counter CN for counting pulse signals from an encoder 29, which will be described later.

[0030] The sheet feeding device 5 also includes an upper surface detection sensor S1 that detects the position of the sheets as the stacking tray 22 is raised and lowered, a lower limit detection sensor S2 that detects the stacking tray 22 at its lower limit position, an intermediate detection sensor S3 that is provided within the raising and lowering range of the stacking tray 22 and detects the stacking tray 22, and a louver detection sensor S4 that detects that the first and second louvers 44, 45 are at their home positions.The sheet feeding device 5 also includes a sheet feed motor MT1 that drives the delivery roller 31, the sheet feed roller 32, and the separation roller 33, a conveyance motor MT2 that drives one of the conveyance rollers 34a, an elevation motor MT3 that raises and lowers the stacking tray 22, first and second fan motors MT4 and MT5 that drive first and second blower fans 42 and 52 that blow air onto the sheets, and a louver motor MT6 that rotates the first and second louvers 44, 45. Further, an encoder 29 is provided which has a slit plate 29a which rotates in synchronization with the rotation of the lift motor MT3, and an optical sensor 29b which has a light emitting element and a light receiving element, and which generates a pulse signal.

[0031] The control unit 100 receives information from the image forming apparatus 2, such as the sheet size and material, the type of sheet (e.g., special paper), and the print mode (e.g., double-sided printing, single-sided printing, reduced printing, enlarged printing), input via the operation unit 15 of the image forming apparatus 2. Based on the various information from the image forming apparatus 2 and the detection results of the upper surface detection sensor S1, the lower limit detection sensor S2, the intermediate detection sensor S3, and the sheet detection sensor S5, the control unit 100 controls the drive of the sheet feed motor MT1, the conveyance motor MT2, the lift motor MT3, and the first and second blower fans 42 and 52. The control unit 100 also transmits information about errors due to damaged parts, problems with lifting or lowering the stacking tray 22, and sheet feeding problems to the image forming apparatus 2, and notifies the same on the display unit 14 of the image forming apparatus 2. In this embodiment, the display unit 14 and the operation unit 15 are provided in the image forming apparatus 2, but they may be attached to the image reading device 3 or the sheet feed device 5.

[0032] Regarding the detection of a paper feed failure, in this embodiment, under normal circumstances, the start of the paper feed motor MT1 during the paper feed operation is used as a trigger to start counting the timer TM, and if the sheet detection sensor S5 does not detect a sheet before the count of the timer TM reaches a preset value, it is determined that a paper feed failure such as a sheet jam or non-feed has occurred. On the other hand, if the sheet detection sensor S5 detects a sheet before the timer TM reaches the set count value, it is determined that the paper feed operation is proceeding normally.

[0033] On the other hand, if the sheets on the stacking tray 22 are magnetic paper and the remaining amount of magnetic paper is less than a predetermined amount, the detection flag FG provided on the rotation shaft 46 of the first and second louvers 44, 45 is triggered by the detection of the louver detection sensor S4 to start counting the timer TM, and if the sheet detection sensor S5 does not detect a sheet before the count value of the timer TM reaches the set value, it is determined that there is a paper feed problem such as a sheet jam or non-feed. That is, in this case, the timer TM starts counting when the first and second louvers 44, 45 of the first and second blower mechanisms 40, 50 move to the open position PB.

[0034] The above-mentioned set value is a preset value obtained by adding a certain count to the count of the timer TM, which corresponds to the distance from the leading edge position of the sheets stacked on the stacking tray 22 in the storage case 20 to the sheet detection position by the sheet detection sensor S5. In this embodiment, the leading edge position of the sheets stacked on the stacking tray 22 is set to the position of the inner wall surface downstream in the sheet feeding direction of the storage case 20, which regulates the leading edge of the sheets when the sheets are set on the stacking tray 22.

[0035] Here, the magnetic paper in this embodiment refers to a magnetic sheet before it is magnetized, and is made, for example, by kneading and hardening powdered magnetic material (neodymium, iron, boron, ferrite, etc.) into a base material of rubber (nitrile rubber, etc.) or plastic (epoxy resin, polyamide resin, etc.). Magnetic paper (magnetic sheet) made of such a base material is soft and flexible, and is placed so as to fit into the cutouts on the loading surface of the loading tray 22.

[0036] When a start button (not shown) provided on the operation unit 15 attached to the image forming apparatus 2 is pressed, the paper feeding operation is executed. FIG. 5 is a main flowchart of the paper feeding operation of the paper feeding device 5, and the paper feeding operation will be explained based on this FIG. 5. First, sheet information input via the operation unit 15 is received from the image forming apparatus 2, and it is determined from the received sheet information whether or not to perform air push (ST10-ST11). In this embodiment, the sheets handled are plain paper, coated paper, and magnetic paper, and air push is performed on cardboard with a basis weight of plain paper of 151 g or more and two types of special sheets, coated paper and magnetic paper, but air push is not performed on plain paper sheets with a basis weight of less than 151 g.

[0037] If air suction is not to be performed, paper feed process 1 is executed (ST12). On the other hand, if air suction is to be performed, the first and second blower fans 42 and 52 and the first and second louvers 44 and 45 are activated as shown in Fig. 8(a) to start air suction (ST13). As a result, air is blown to the widthwise edges of the sheets on stacking tray 22 for a certain period of time before the sheets on stacking tray 22 are fed, allowing the sheets on stacking tray 22 to be separated before feeding.

[0038] After a certain time has elapsed since the start of air pumping, if the sheet on stacking tray 22 is magnetic paper, paper feed process 2 is executed (ST14, ST15), and if the sheet is not magnetic paper, paper feed process 1 is executed (ST14, ST12). The type of sheet on stacking tray 22 is determined based on sheet information sent from image forming apparatus 2, and paper feed process 2 is executed if the type of sheet is magnetic paper. Information regarding the type of sheet is input by the user via operation unit 15.

[0039] Fig. 6 is a flowchart showing the paper feed process 1. This paper feed process 1 is executed when there is no air cyst as shown in Fig. 5 and when the type of sheets on the stack tray 22 is other than magnetic paper.

[0040] In the paper feed process 1, first, the delivery roller 31, the paper feed roller 32, and the separation roller 33 are activated to start the paper feed operation of the sheets on the stack tray 22 (ST20). Then, the start of paper feed (start of the paper feed motor MT1) is used as a trigger to start the timer TM, which then starts counting (ST21).

[0041] If the sheet being fed by the feed rollers 31 and the feed rollers 32 is detected by the sheet detection sensor S5 before the count value of the timer TM reaches a preset value, the sheet feeding operation is stopped after a predetermined time (ST22-ST25). This stops the feed rollers 31, the feed rollers 32, and the separation roller 33. At this time, the leading edge of the sheet is nipped by the pair of conveyance rollers 34a and 34b, and the sheet is conveyed downstream by the drive of the pair of conveyance rollers 34a and 34b even when the feed rollers 31, the feed rollers 32, and the separation roller 33 are stopped. If the sheet conveyed downstream by the pair of conveyance rollers 34a and 34b is the last sheet of the job, the sheet feeding operation is ended (ST26). If it is not the last sheet, feeding of the next sheet begins.

[0042] On the other hand, if the count value of the timer TM reaches or exceeds the set value before the sheet is detected by the sheet detection sensor S5, it is determined that there is a paper feed failure such as a sheet jam or non-feeding of the sheet, and the delivery roller 31, paper feed roller 32, and separation roller 33 are stopped to stop the paper feed operation (ST27). Then, a message indicating that there is a paper feed failure is sent to the image forming device 2 (ST28). Note that the image forming device 2 that has received the paper feed failure is configured to notify the user of the paper feed failure on the display unit 14.

[0043] 7 is a flowchart showing the paper feed process 2. This paper feed process 2 is executed when the sheets on the stack tray 22 are magnetic paper. The paper feed process 2 will be described with reference to FIG.

[0044] In the sheet feeding process 2, first, the delivery roller 31, the sheet feed roller 32, and the separation roller 33 are activated to start the sheet feeding operation on the stacking tray 22 (ST30). At the same time as the start of this sheet feeding operation, the timer TM is activated and starts counting (ST31). When the timer TM starts counting, it is determined whether or not the number of remaining sheets on the stacking tray 22 is equal to or greater than a predetermined number (ST32). If the number of remaining sheets is equal to or greater than the predetermined number, the count value of the timer TM and whether or not the sheet detection sensor S5 has detected a sheet are monitored (ST33-ST34). If the sheet detection sensor S5 detects a sheet being fed by the delivery roller 31 and the sheet feed roller 32 before the count value of the timer TM reaches a preset value, the delivery roller 31, the sheet feed roller 32, and the separation roller 33 are stopped after a predetermined time, and the sheet feeding operation is stopped (ST33-S36). At this time, the leading edge of the sheet is nipped by the pair of conveying rollers 34a and 34b, and the sheet is conveyed downstream by the drive of the pair of conveying rollers 34a and 34b even when the delivery roller 31, the paper feed roller 32, and the separation roller 33 are stopped. If the sheet conveyed downstream by the pair of conveying rollers 34a and 34b is the last sheet of the job, the paper feeding operation ends (ST37). If it is not the last sheet, feeding of the next sheet begins (ST37).

[0045] In step 33 (ST34), if the count value of timer MT reaches or exceeds a set value before a sheet is detected by sheet detection sensor S5, it is determined that there is a paper feed failure such as a sheet jam or non-feeding of a sheet, and the delivery roller 31, paper feed roller 32, and separation roller 33 are stopped to stop the paper feed operation (ST38). Then, a message indicating that there is a paper feed failure is sent to image forming apparatus 2 (ST39). Note that image forming apparatus 2, which has received the paper feed failure in paper feed process 2, is configured to notify the display unit 14 of the paper feed failure.

[0046] On the other hand, if the remaining amount of sheets is less than a predetermined amount, the louver detection sensor S4 turns ON. That is, when it is detected that the first and second louvers 44, 45, which swing up and down in the air cylinders activated in step 13 (ST13) of FIG. 5, have moved to the open position PB, which is their home position, the louver motor MT6 is stopped, and the first and second louvers 44, 45 are stopped at the open position PB (ST40-ST41). In other words, the first and second louvers 44, 45, which reciprocate up and down at a constant interval, stop when they reach the open position PB as shown in FIG. 8(b) when the remaining amount of sheets becomes less than a predetermined amount. Thereafter, as shown in FIG. 8(c), they remain at the open position PB until at least the last sheet is fed.

[0047] As a result, when the final sheet is fed, the first and second louvers 44, 45 are in the open position PB, air enters between the final sheet and the upper surface of the stacking tray 22, and feeding begins with the transport load of the final sheet reduced, thereby reducing the frequency of paper feeding failures caused by the count value of the timer MT reaching or exceeding the set value.

[0048] After the first and second louvers 44, 45 are stopped, the count value of the timer TM and whether or not the sheet detection sensor S5 has detected a sheet are monitored (ST42-ST43). If the sheet detection sensor S5 detects a sheet before the count value of the timer TM reaches the set value, the paper feed operation is stopped after a predetermined time as described above (ST42-ST44, ST35). If the sheet detected by the sheet detection sensor S5 is the last sheet of the job, the paper feed operation is terminated; if not, paper feed process 2 for the next sheet is started (ST37). Furthermore, if the count value of the timer MT reaches the set value before the sheet is detected by the sheet detection sensor S5, the paper feed operation is stopped due to a paper feed error such as a sheet jam or non-feed, and jam information is sent to the image forming apparatus 2 (ST45-ST46).

[0049] In step 40, if the louver detection sensor S4 is OFF, it is determined that the first and second louvers 44, 45 have not yet reached the open position PB, and the first and second louvers 44, 45 continue to move to the open position PB while the count value of the timer TM and whether or not the sheet detection sensor S5 has detected a sheet are monitored (ST42-ST43). If the sheet detection sensor S5 detects a sheet before the count value of the timer TM reaches the set value, the paper feed operation is stopped after a predetermined time, and a determination is made as to whether or not the job is complete (ST43-ST44, ST36). If the count value of the timer MT reaches the set value before the sheet detection sensor S5 detects a sheet, it is determined that a paper feed error, such as a sheet jam or non-feed, has occurred, and the paper feed operation is stopped, and information about the paper feed error is sent to the image forming apparatus 2 (ST45-ST46).

[0050] Now, to explain remaining amount detection in this embodiment, in this embodiment, the remaining amount of sheets is calculated from the position of stacking tray 22 when the top sheet on stacking tray 22 is at sheet feed position P1. As described above, the position of stacking tray 22 is determined by generating a pulse signal synchronized with the rotation of lifting motor MT3 that lifts and lowers stacking tray 22 by encoder 29, counting the generated pulse signal by counter CN, and specifying the position of the stacking tray based on this count value.

[0051] Specifically, the counter CN counts the pulse signals of the encoder 29 from the point in time when the stacking tray 22 is detected by the intermediate detection sensor S3. As shown in FIG. 8(b), the measurement counter value counted by the counter CN corresponds to the lift distance LX1 of the stacking tray 22 from the detection position of the intermediate detection sensor S3, and this lift distance LX1 identifies the position of the stacking tray 22. The remaining number of sheets is detected based on a value obtained by subtracting the measurement count value from a set count value of the number of pulses corresponding to the distance from the detection position P2 of the intermediate detection sensor S3 to the sheet feed position P1, which is the upper limit of the lift range of the stacking tray 22. In other words, the subtracted value corresponds to the distance LX2 from the upper surface of the stacking tray 22 to the uppermost sheet on the stacking tray 22 positioned at the sheet feed position P1. Therefore, the smaller the subtracted value, the shorter the distance LX2 and the fewer the remaining number of sheets. The aforementioned set count value is a value obtained by counting the number of pulses of the encoder 29 when the loading tray 22 is raised, which is the distance LA from the detection position P2 of the intermediate detection sensor S3 to the paper feed position P1, which is the upper limit of the lifting range of the loading tray 22, and is set in advance.

[0052] According to this embodiment, when the sheets on stacking tray 22 are magnetic paper and the remaining amount of sheets is less than a predetermined amount, first and second louvers 44, 45 of first and second air blowing mechanisms 40, 50 are stopped at open position PB and maintained in that state. As a result, timer TM starts counting in a state where the transport load of the final sheet has been reduced by the air blowing from first and second air blowing mechanisms 40, 50, and therefore it is possible to reduce the frequency of paper feed failures caused by the count value of timer TM reaching the set value.

[0053] In the above embodiment, the first and second louvers 44, 45, which periodically reciprocate up and down, are stopped when they reach the open position PB after the number of sheets remaining on the stacking tray 22 becomes less than a predetermined amount. However, the reciprocating movement may be stopped and the first and second louvers 44, 45 may be forcibly moved to the open position PB when the number of sheets remaining on the stacking tray 22 becomes less than a predetermined amount.

[0054] In this embodiment, the remaining amount of sheets on the stacking tray 22 is detected by the amount of lift of the stacking tray 22 from the point in time when the intermediate detection sensor S3 detects the stacking tray 22, but it may also be detected by the amount of lift of the stacking tray 22 from the point in time when the lower limit detection sensor S2 detects the stacking tray 22. In this case, when the power is turned on or the storage case 20 is attached, the stacking tray 22 is lowered to the lower limit position and then raised after being detected by the lower limit detection sensor S2.

[0055] In addition, in this embodiment, the remaining number of sheets on the stacking tray 22 is detected using the encoder 29, but it is also possible to provide multiple sensors to detect the stacking tray 22 in the direction in which the stacking tray 22 is raised and lowered, and to detect the position of the stacking tray 22 based on the detection results of these multiple sensors, thereby detecting the remaining number of sheets on the stacking tray 22.

[0056] In the present embodiment described above, paper feed process 2 is performed when the sheet is magnetic paper, but by performing paper feed process 2 on sheets that are difficult to transport without air blowing, including sheets that are heavier than regular paper but have lower rigidity, it is possible to obtain the same effects and advantages as with magnetic paper in the above embodiment.

[0057] Although the above embodiment has been described using magnetic paper, the present invention is not limited to magnetic paper and can also be applied to sheets where the transport load of the final sheet on a stacking tray is greater than that of sheets other than the final sheet, causing delays in sheet transport. [Explanation of symbols]

[0058] 2. Image forming device 5 Paper feeder 14 Display section 15 Control section 20 Storage 22 Loading tray 23 Side control plate 24 Side control plate 28 Lifting mechanism 29 Encoder 30 Feeding mechanism 40 First blower mechanism 42 Second blower fan 44 First Louver 45 Second Louver 46 Rotating shaft 50 Second blower mechanism 52 Second blower fan 100 control section TM Timer CN Counter S1 Upper surface detection sensor S2 Lower limit detection sensor S3 Intermediate detection sensor S4 Louver detection sensor S5 Sheet detection sensor MT3 lift motor MT6 Louver Motor FG detection flag

Claims

1. A sheet feeding device including: a stacking tray on which sheets are stacked; a blowing unit having a moving member that moves back and forth in an up and down direction to change an air blowing range at an air blowing port, and that blows air from the air blowing port to an edge of a sheet on the stacking tray; and a sheet feeding unit that feeds the sheets on the stacking tray, The moving member stops at a predetermined position where air is blown onto the last sheet on the stacking tray before the sheet feeding operation by the sheet feeding means is started.

2. a detection unit for detecting a sheet fed by the sheet feeding unit; 2. The paper feeding device according to claim 1, wherein if the detection means does not detect a sheet within a set time from the point in time when the paper feeding means starts feeding the paper, the paper feeding means stops the paper feeding operation.

3. a remaining amount detecting means for detecting the remaining amount of sheets on the stacking tray; 2. The sheet feeding device according to claim 1, wherein the moving member stops at the predetermined position when the remaining amount detecting means detects that the remaining amount of sheets on the stacking tray is equal to or less than a predetermined amount.

4. 2. The paper feeder according to claim 1, wherein the predetermined position is below the stacking tray.

5. A paper feeding device described in any one of claims 1 to 4, wherein when the sheets on the stacking tray are at least heavier than regular paper and are soft special sheets, the moving member stops at a predetermined position where air is blown onto the last sheet on the stacking tray before the paper feeding operation by the paper feeding means begins.

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