JP2025180079A - Paper feeder - Google Patents

Abstract

An object of the present invention is to prevent paper feeding problems caused by louvers in a blower mechanism.
[Solution] In a paper feeding device 5 equipped with a paper feeding mechanism 30 that feeds sheets on a stacking tray 22 and air blowing mechanisms 40, 50 having louvers 44, 45 that change the air blowing range at air outlets 41b, 51b, the louvers 44, 45 of the air blowing mechanisms 40, 50 are stopped at an open position PB and the air outlets 41b, 51b are opened before the paper feeding operation by the paper feeding mechanism 30 is started for at least the last sheet on the stacking tray 22.
[Selected figure] Figure 8

Description

The present invention relates to a paper feeder equipped with a blower that blows air onto the sides of sheets stacked in a storage compartment.

Conventionally, image forming devices such as printers and copiers are equipped with a paper feeder that separates sheets stacked on a stacking tray one by one and supplies them to the image forming device.

The paper feed device is equipped with a liftable stacking tray on which sheets are stacked, a feed roller that contacts the top 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 transport rollers that transport the separated sheets toward the image forming device. The sheets on the liftable tray are then guided along the paper feed path to the image forming device by the feed roller, separation mechanism, and transport roller pair.

Such paper feeders are equipped with a detection means for detecting paper feed problems such as sheet jams and non-feeds. A known detection means for this is a timer that starts counting when the feed roller is activated, and determines whether a paper feed problem such as a sheet jam or non-feed occurs based on whether a detection sensor located between the separation mechanism and the pair of conveying rollers detects the leading edge of the sheet within a set count value.

Some printers also include 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 with an intake port and an outlet port, a blower fan located within the duct, and a movable member attached to the duct's outlet port. The duct's outlet port is positioned to blow air onto the top of the sheets stacked on the stacking tray. Specifically, the outlet port is positioned so that the sheet feed position for feeding the sheets is approximately centered vertically relative to the outlet port. The blower fan rotates to suck air from the duct's intake port 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 top side of the stacked sheets, inserting air between the sheets to facilitate separation when unloading them. The movable member is configured to reciprocate at a regular interval between an open position that opens the outlet port and a closed position that closes the outlet port. As the movable member moves upward from the open position to the closed position, it gradually closes the air outlet from below, and as it moves downward from the closed position to the open position, it gradually opens the air outlet from above. In this way, by moving the movable member back and forth to change the open range of the air outlet, the air pressure blown onto the edge of the sheet varies in strength, 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 paper feed problems.

Japanese Patent Application Laid-Open No. 2022-103483

In recent years, there has been a demand for such paper feeders to accommodate special sheets such as envelopes, label sheets, and magnetic sheets. Among these special sheets, magnetic sheets are characterized by their heavy weight, low rigidity, and flexibility. For this reason, when feeding the last magnetic sheet on the stacking tray, it gets caught on the notches and 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, making it easier to feed. At this time, the last magnetic sheet lifts 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 edge of the last magnetic sheet is closed, so air is not blown onto the stacking tray or the last magnetic sheet, and the last magnetic sheet does not float up. If the timer used to determine 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, and the timer count value exceeds the set value, causing frequent paper feed stoppages due to non-feeding.

The present invention was made in consideration of the above problems, and aims to prevent sheet feeding problems caused by moving members.

To achieve the above objective, the paper feed device of the present invention comprises a stacking tray on which sheets are stacked, a moving member that moves back and forth in the vertical direction to change the air blowing range at the air outlet, and blows air from the air outlet to the edges of the sheets on the stacking tray, and a paper feed means that feeds the sheets on the stacking tray, and the moving member stops at a predetermined position where air is blown to the last sheet on the stacking tray before the paper feed means begins feeding the last sheet.

The above configuration prevents non-feeding caused by the position of the moving member.

1 is a cross-sectional view showing an example of an image forming system including a paper feeder according to the present invention. FIG. 2 is a conceptual diagram illustrating a configuration of a paper feed device. FIG. 2 is a perspective view showing a blower mechanism of the paper feeder; FIG. 2 is a block diagram showing a control system configuration of the paper feeder. FIG. 4 is a flowchart showing a paper feeding operation in the paper feeding device. FIG. 2 is a flowchart showing a paper feed process 1 in a paper feed operation. FIG. 10 is a flowchart showing a paper feed process 2 in the paper feed operation. 10A and 10B are state diagrams showing states of the stacking tray and the louvers during a paper feeding operation.

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

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 to a sheet supplied from either the upper or lower cassette 10, 11 or the paper feeder 5. The sheet with the transferred toner is sent to the fixing roller 7f, 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.

The upper and lower cassettes 10, 11 are each provided with a paper feed mechanism 10a, 10b that feeds the sheets stored in each cassette 10, 11. The sheets stored in each cassette 10, 11 are separated into individual sheets by each paper feed mechanism 10a, 10b and sent to the transport path 12. The sheets sent from each paper feed mechanism 10a, 10b to the transport path 12 are then sent to the image forming unit 7 via the transport path 12.

The document reading device 3 is equipped with a photoelectric conversion element 3a that converts received light into an electrical signal to generate image data, an optical system unit 3b that irradiates the document with light and directs the light reflected from the document to the photoelectric conversion element 3a, a reading glass 3c that reads the 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 using the optical system unit 3b and the photoelectric conversion element 3a, and the read image data is transferred to the image forming device 2.

Figure 2 is a conceptual diagram showing the configuration of the paper feeder 5, and Figure 3 is a perspective view showing the air blowing mechanism provided in the paper feeder 5. Note that the sheets handled by the image forming device 2 and paper feeder 5 include plain paper as well as overhead projector sheets, tracing paper, coated paper, etc., and are capable of handling multiple sheet sizes.

As shown in FIG. 1, slide rails 21a and 21b are provided on both the left and right sides of the storage cabinet 20. The storage cabinet 20 is supported on the housing 50 so that it can be pulled out via the slide rails 21a and 21b. The feed mechanism 30 includes a feed roller 31, a feed roller 32, and a separation roller 33 driven by a paper feed motor MT1. Sheets stored in the storage cabinet 20 are fed by the feed roller 31 and separated and fed one by one by the feed roller 32 and separation roller 33. In addition, downstream of the feed mechanism 30 in the sheet feed direction are provided a pair of transport rollers 34a and 34b driven by a transport motor MT2, and sheets fed by this pair of transport rollers 34a and 34b are supplied to the image forming device 2.

A stacking tray 22 that can be raised and lowered is provided within the storage cabinet 20. This stacking tray 22 is formed from a flat plate on which multiple sheets can be stacked. The stacking tray 22 has notches for the movement of a pair of side regulating plates 23 and 24 (described below), as well as a notch for the movement of a trailing edge regulating plate 25.

In addition, above the storage cabinet 20, an upper surface detection sensor S1 is provided to detect the position of the top surface of the sheets stacked on the stacking tray 22 and position the top sheet at the paper feed position. A lower limit detection sensor S2 is provided below the storage cabinet 20. The stacking tray 22 is configured to be able to be raised and lowered by a lifting mechanism 28 between the paper 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.

The lifting mechanism 28 includes a wire 26 attached to the stacking tray 22, a take-up pulley 27 that winds up the wire 26, a lifting motor MT3 that rotates the take-up pulley 27 in one direction to wind up the wire 26, thereby raising 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 composed of a combination of transmission members such as drive gears and timing belts.

A slit plate 29a of an encoder 29 is attached to the shaft of the lift motor MT3 or the rotation axis of the drive transmission gear to detect the remaining number of sheets on the stack tray 22. The encoder 29 uses an optical sensor 29b to detect the slits in the slit plate 29a, which rotates in sync with the lift motor MT3, and generates a pulse signal. The position of the stack tray 22 is then 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 stack tray 22.

A pair of side regulating plates 23, 24 are provided within the storage cabinet 20 to align the sheet width direction, which is 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 within the storage cabinet 20. In addition, a trailing edge regulating plate 25 is provided that moves in the sheet feed direction to align the trailing edge of the sheet in the feed direction. Note that Figures 1 and 2 only show the first side regulating plate 23, which is located on one end of the sheet width direction; the second side regulating plate 23 is not shown.

As shown in Figures 2 and 3, a first air blowing mechanism 40 serving as a first air blowing means and located downstream in the sheet feed direction, and a second air blowing mechanism 50 serving as a second air blowing means and located upstream in the sheet transport direction, are provided on the rear side of the sheet-restricting surface of the first side restriction 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 them, thereby separating the sheets. The first side restriction plate 23, first air blowing mechanism 40, and second air blowing mechanism 50 are integrated into a unit, and are configured so that the first air blowing mechanism 40 and second air blowing mechanism 50 also move as the first side restriction plate 23 moves.

The first blower 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 top 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) suitable for blowing air using ducts are used as the first blower fan 42 and the second blower fan 52 described below.

A first louver 44 is provided on the air outlet 41b side of 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 by a pivot 44a at one end on the far side of the first duct 41 and a pivot 46 at the other end. The first louver 44 moves between an open position PB (see the position of the first louver 44 indicated by the solid line in Figure 8(a)) in which the air outlet 41b is fully open to blow air toward the edge of the sheets on the stack tray 22, and a blocked position PA (see the position of the first louver 44 indicated by the dashed line in Figure 8(a)) in which the portion of the air outlet 41b facing the edge of the sheets is blocked to prevent air from being 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. As the first louvers 44 rise from the open position PB to the blocked position PA, the opening width of the air outlet gradually narrows, and as they descend from the blocked position PA to the open position PB, the opening width of the air outlet 41b gradually widens. 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 edges of the sheets, varying the strength of the air pressure and changing the direction of the air, improving sheet separation accuracy.

The second blower mechanism 50 is positioned 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 positioned within the second duct 51. The second duct 51 is positioned so 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 stack 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 stack tray 22.

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 by 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. 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 when blowing air to separate sheets. 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, changing the range of air blown onto the edges of the sheets, thereby varying the strength of the air pressure and changing the direction of the air.

To explain the first and second louvers 44, 45 in more detail, as shown in Figure 3, the first and second louvers 44, 45 are axially supported on a common rotary shaft 46. This rotary shaft 46 is provided with multiple drive gears RZ that are drivingly connected to the 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. The rotary shaft 46 is also provided with a detection flag FG, which is located 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 the 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 limit 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.

Figure 4 is a block diagram of the control system of the paper feeder 5 shown in Figure 2. As shown in Figure 5, the paper feeder 5 is equipped with a control unit 100 having a CPU, ROM storing programs for executing various processes, and 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 the encoder 29, which will be described later.

The sheet feeder 5 also includes an upper surface detection sensor S1 that detects the position of 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 located 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 when the first and second louvers 44, 45 are in their home positions. The sheet feeder 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 transport motor MT2 that drives one of the transport rollers 34a, an elevator motor MT3 that raises and lowers the stacking tray 22, first and second fan motors MT4, MT5 that drive the first and second blower fans 42, 52 that blow air onto the sheets, and a louver motor MT6 that rotates the first and second louvers 44, 45. Furthermore, an encoder 29 is provided which has a slit plate 29a that rotates in synchronization with the rotation of the lift motor MT3, and an optical sensor 29b that has a light-emitting element and a light-receiving element, and generates a pulse signal.

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

Now, regarding the detection of paper feed errors, in this embodiment, under normal circumstances, the timer TM starts counting when the paper feed motor MT1 is started during paper feed operation, and if the sheet detection sensor S5 does not detect a sheet before the timer TM count reaches a preset value, it is determined that a paper feed error 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.

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 attached to the pivot shaft 46 of the first and second louvers 44, 45 is triggered by the detection of the louver detection sensor S4, which starts counting the timer TM. If the sheet detection sensor S5 does not detect a sheet before the timer TM count value reaches the set value, a paper feed error such as a sheet jam or non-feed is determined. In other words, 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.

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 of the sheets loaded 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 of the sheets loaded on the stacking tray 22 is set to the position of the inner wall surface downstream in the paper feed direction of the storage case 20, which regulates the leading edge of the sheets when they are set on the stacking tray 22.

In this embodiment, magnetic paper refers to a magnetic sheet before it is magnetized, and is made, for example, from a base material of rubber (nitrile rubber, etc.) or plastic (epoxy resin, polyamide resin, etc.) into which powdered magnetic material (neodymium, iron, boron, ferrite, etc.) is kneaded and hardened. Magnetic paper (magnetic sheet) made from such a base material is soft and flexible, and is placed so that it fits into the cutouts on the loading surface of the loading tray 22.

When a start button (not shown) on the operation unit 15 attached to the image forming device 2 is pressed, the paper feeding operation is executed. Figure 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 Figure. First, sheet information entered via the operation unit 15 is received from the image forming device 2, and a determination is made based on the received sheet information as to 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 plain paper with a basis weight of 151g or more and two types of special sheets: coated paper and magnetic paper. Air push is not performed on plain paper sheets with a basis weight of less than 151g.

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

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

Figure 6 is a flowchart showing paper feed process 1. This paper feed process 1 is executed when there is no air cyst, as shown in Figure 5, and when the type of sheet on the stacking tray 22 is other than magnetic paper.

In paper feed process 1, first, the delivery roller 31, paper feed roller 32, and separation roller 33 are activated to start feeding the sheets on the stack tray 22 (ST20). Then, the start of paper feeding (starting of paper feed motor MT1) triggers the activation of timer TM, which then starts counting on timer TM (ST21).

If the sheet being fed by the feed roller 31 and feed roller 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 roller 31, feed roller 32, and separation roller 33. At this time, the leading edge of the sheet is nipped between the pair of conveying rollers 34a and 34b, and the sheet is transported downstream by the drive of the pair of conveying rollers 34a and 34b, even when the feed roller 31, feed roller 32, and separation roller 33 are stopped. If the sheet transported downstream by the pair of conveying rollers 34a and 34b is the last sheet of the job, the sheet feeding operation ends (ST26). If it is not the last sheet, feeding of the next sheet begins.

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 error, such as a sheet jam or a non-feed, 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 a paper feed error is sent to the image forming device 2 (ST28). When the image forming device 2 receives the paper feed error, it displays a notification of the paper feed error on the display unit 14.

Figure 7 is a flowchart showing paper feed process 2. Paper feed process 2 is executed when the sheets on stack tray 22 are magnetic paper. Paper feed process 2 will be explained based on Figure 7.

In paper feed process 2, the feed rollers 31, feed rollers 32, and separation rollers 33 are first activated to start feeding sheets from the stack tray 22 (ST30). Simultaneously with the start of this feeding operation, the timer TM is activated and begins counting (ST31). When the timer TM starts counting, it is determined whether the number of remaining sheets on the stack 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 feed rollers 31 and feed rollers 32 before the count value of the timer TM reaches a preset value, the feed rollers 31, feed rollers 32, and separation rollers 33 are stopped after a predetermined time, and the sheet feeding operation is stopped (ST33-ST36). At this time, the leading edge of the sheet is nipped by the pair of transport rollers 34a and 34b, and the sheet is transported downstream by the drive of the pair of transport rollers 34a and 34b, even if the delivery roller 31, paper feed roller 32, and separation roller 33 are stopped. If the sheet transported downstream by the pair of transport 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).

In step 33 (ST34), if the count value of timer MT reaches or exceeds the set value before a sheet is detected by sheet detection sensor S5, it is determined that there is a paper feed error, such as a sheet jam or non-feed, 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 a paper feed error is sent to image forming device 2 (ST39). Incidentally, upon receiving the paper feed error in paper feed process 2, image forming device 2 is configured to notify the user of the paper feed error on display unit 14.

On the other hand, if the remaining sheet quantity is less than the predetermined quantity, the louver detection sensor S4 turns ON. In other words, when it detects that the first and second louvers 44, 45, which swing up and down in the air cylinder 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, causing the first and second louvers 44, 45 to stop 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 sheet quantity becomes less than the predetermined quantity. Thereafter, as shown in FIG. 8(c), they remain at the open position PB until at least the last sheet is fed.

As a result, when the final sheet is fed, the first and second louvers 44, 45 are in the open position PB, allowing air to enter between the final sheet and the top 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 timer MT count value reaching or exceeding the set value.

After the first and second louvers 44, 45 are stopped, the count value of timer TM and whether or not sheet detection sensor S5 detects a sheet are monitored (ST42-ST43). If sheet detection sensor S5 detects a sheet before the count value of 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 sheet detection sensor S5 is the last sheet of the job, the paper feed operation is terminated. If it is not the last sheet, paper feed process 2 for the next sheet is started (ST37). Furthermore, if the count value of timer MT reaches the set value before a sheet is detected by 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 image forming device 2 (ST45-ST46).

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

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

Specifically, counter CN counts the pulse signals of encoder 29 from the point at which the stacking tray 22 is detected by the intermediate detection sensor S3. As shown in Figure 8(b), the measurement counter value counted by 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 the value obtained by subtracting the measurement count value from the set count value of the number of pulses corresponding to the distance from detection position P2 of the intermediate detection sensor S3 to 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 top surface of the stacking tray 22 to the uppermost sheet on the stacking tray 22 positioned at feed position P1. Therefore, the smaller the subtracted value, the shorter the distance LX2 and the fewer the remaining sheets. The aforementioned set count value is a preset value obtained by counting the number of pulses of the encoder 29 when the stacking tray 22 is raised, which is the distance LA from the detection position P2 of the intermediate detection sensor S3 to the sheet feed position P1, which is the upper limit of the lifting range of the stacking tray 22.

In this embodiment, when the sheets on the stacking tray 22 are magnetic paper and the remaining amount of sheets falls below a predetermined amount, the first and second louvers 44, 45 of the first and second air blowing mechanisms 40, 50 are stopped in the open position PB and maintained in that state. This allows the timer TM to start counting when the transport load of the final sheet has been reduced by the air blowing from the first and second air blowing mechanisms 40, 50, reducing the frequency of paper feed failures caused by the timer TM count value reaching the set value.

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 falls below a predetermined amount. However, the reciprocating motion 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 falls below a predetermined amount.

In this embodiment, the remaining number of sheets on the stacking tray 22 is detected by the amount of lift of the stacking tray 22 from the point at which the intermediate detection sensor S3 detects the stacking tray 22. However, it may also be detected by the amount of lift of the stacking tray 22 from the point at which the lower limit detection sensor S2 detects the stacking tray 22. In this case, when the power is turned on or the storage cabinet 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.

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 and the remaining number of sheets on the stacking tray 22 based on the detection results of these multiple sensors.

In the embodiment described above, paper feed process 2 is performed when the sheet is magnetic paper. However, by performing paper feed process 2 on sheets that are difficult to transport without airflow, including sheets that are heavier but less rigid than regular paper, it is possible to obtain the same effects and benefits as with magnetic paper in the embodiment described above.

In the above embodiment, magnetic paper was used, but the present invention is not limited to magnetic paper and can also be applied to sheets where the transport load of the last sheet on a stacking tray is greater than that of sheets other than the last sheet, causing delays in sheet transport.

2 Image forming apparatus 5 Paper feeder 14 Display unit 15 Operation unit 20 Storage 22 Stacking tray 23 Side regulating plate 24 Side regulating plate 28 Lifting mechanism 29 Encoder 30 Feeding mechanism 40 First air blowing mechanism 42 Second air blowing fan 44 First louver 45 Second louver 46 Rotating shaft 50 Second air blowing mechanism 52 Second air blowing fan 100 Control unit 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 Lifting motor MT6 Louver motor FG Detection flag

Claims (5)

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