JP7252840B2 - Media feeder - Google Patents

Description

TECHNICAL FIELD The present invention relates to a medium supply device having a supply tray on which media are stacked and raised and lowered.

2. Description of the Related Art Conventionally, in an image forming apparatus such as an inkjet recording apparatus and an electronic copier, there are cases where sheets stacked in a paper feed tray protrude from the paper feed tray in the paper feed direction after a printing operation is completed. In this case, if the paper feed tray is pulled out in a direction orthogonal to the feeding direction, the protruding paper contacts the housing, and the paper is torn or bent.

Therefore, an image forming apparatus has been proposed in which the shape of the opening of the housing for pulling out the paper feed tray is enlarged so that the paper protruding from the paper feed tray does not come into contact with the housing (see, for example, Japanese Unexamined Patent Application Publication No. 2002-200012). ).

Further, a paper feeding device has been proposed that includes an inclined guide member so as to return the protruding paper to the paper feeding tray when the paper feeding tray is pulled out (see, for example, Japanese Unexamined Patent Application Publication No. 2002-200022).

Further, there has been proposed a paper feeder that pushes up the paper feed tray obliquely a plurality of times after the paper feed operation is completed (see, for example, Japanese Patent Application Laid-Open No. 2002-200034).

JP-A-1-294074 Japanese Patent No. 3912933 JP-A-4-308128

As described above, in an image forming apparatus in which the shape of the opening for pulling out the paper feed tray is enlarged so that the paper ejected from the paper feed tray does not come into contact with the housing, strength cannot be maintained. If the housing is made strong in order to maintain the strength of the housing, the size of the device will increase.

In addition, as described above, in a paper feeder having a guide member that is inclined so as to return the ejected paper to the paper feed tray when the paper feed tray is pulled out, a space for arranging the guide member is required. Therefore, the size of the device is increased. In addition, there is a possibility that the paper does not move smoothly along the guide member and the paper is folded.

In addition, as described above, in a paper feeder that pushes up the paper feed tray obliquely multiple times after the paper feed operation is completed, a mechanism for performing the push-up operation is arranged, which leads to an increase in the size of the device. . In addition, the user cannot pull out the paper feed tray during the push-up operation a plurality of times, which reduces the user's workability.

As described above, conventionally, in a medium feeding device (for example, a paper feeding device) that feeds a medium (for example, paper), the medium feeding device becomes larger, or the user's operability deteriorates.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a medium feeder capable of returning a medium ejected from a feed tray to the feed tray with a simple configuration while suppressing deterioration of user's workability.

In one aspect, the medium supply device includes a supply tray on which media are stacked, a feeding section for feeding the uppermost medium stacked on the supply tray, an elevation drive section for lifting and lowering the supply tray, and the uppermost medium. a medium height detection unit for detecting that the height of the upper medium is at the supply height; a control unit for controlling, the control unit detects that the height of the uppermost medium is at the supply height by the medium height detection unit after the supply tray starts to descend. If the time until the supply tray runs out is longer than the specified time, the up-and-down driving unit is controlled to increase the amount of descent of the supply tray.

According to the aspect, it is possible to return the medium ejected from the supply tray to the supply tray with a simple configuration while suppressing deterioration of user's workability.

1 is a perspective view showing a medium feeding device and an image forming device according to one embodiment; FIG. 1 is a front view showing internal structures of a medium feeding device and an image forming apparatus according to an embodiment; FIG. 3 is a diagram showing a control configuration of a medium feeding device according to one embodiment; FIG. 1 is a perspective view showing a medium feeding device with a drawer pulled out according to one embodiment; FIG. FIG. 10 is a front view (part 1) for explaining the operation of the medium feeding device according to the embodiment; FIG. 11 is a front view (part 2) for explaining the operation of the medium feeding device according to the embodiment; FIG. 12 is a front view (part 3) for explaining the operation of the medium feeding device according to the embodiment; FIG. 3 is a perspective view (part 1) showing a feeding unit and a medium height detection unit according to one embodiment; FIG. 11 is a perspective view (part 2) showing the feeding unit and the medium height detection unit according to the embodiment; FIG. 3 is a perspective view showing a medium height detector in one embodiment; FIG. 10 is a diagram showing the relationship between the remaining amount and size of media and the amount of descent of the supply tray in one embodiment. 4 is a flowchart for explaining processing in one embodiment; 1 is a perspective view for explaining a medium feeding device according to one embodiment; FIG. FIG. 11 is a perspective view for explaining a medium feeding device in a comparative example;

A medium feeding device according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing a medium feeding device 1 and an image forming device 100 according to one embodiment.

FIG. 2 is a front view showing internal structures of the medium feeding device 1 and the image forming apparatus 100. As shown in FIG.
1 and 2, as well as FIGS. 4 to 10, 13, and 14 to be described later, the direction D1 of feeding the medium M is to the right, and the drawing of the drawer section 40 Although the direction D2 is the forward direction and is merely a direction for convenience of explanation, for example, the up-down direction is the vertical direction, and the front-rear direction and the left-right direction are the horizontal directions.

As shown in FIGS. 1 and 2, the medium supply device 1 is connected to the image forming apparatus 100 and supplies the image forming apparatus 100 with the medium M shown in FIG. The medium M is, for example, a sheet of paper. The medium feeding device 1 and the image forming device 100 can be collectively called a printing system. In other words, the printing system includes the medium feeding device 1 and the image forming device 100 . Note that the medium feeding device 1 may be a medium feeding device integrally provided in the image forming apparatus 100 .

As shown in FIG. 2, the image forming apparatus 100 includes a first paper feed tray 111, a second paper feed tray 112, a third paper feed tray 113, a transport path 121, and a plurality of transport rollers 122. , a printing unit 130 , a suction transport unit 140 , and a paper discharge tray 150 .

The first paper feed tray 111 is arranged on the left side of the image forming apparatus 100 above the medium feeding device 1 . The second paper feed tray 112 and the third paper feed tray 113 are arranged inside the image forming apparatus 100 . Media M are stacked on the first paper feed tray 111 , the second paper feed tray 112 , and the third paper feed tray 113 .

The transport path 121 is a path along which the medium M is transported. In FIG. 2, the conveying path 121 is indicated by solid lines with appropriate arrows. The transport path 121 has a reversing path 121a for reversing the medium M for double-sided printing.

The printing unit 130 has, for example, a line head type inkjet head (not shown) for each color used for printing. The printing method of the printing unit 130 may be a printing method other than the inkjet printing method.

The suction transport section 140 is arranged to face the printing section 130 . The conveying unit 140 conveys the adsorbed medium M using a conveying belt. Note that the suction transport unit 140 is an example of a transport unit that transports the medium M. As shown in FIG.

The paper discharge tray 150 is arranged in the upper part of the image forming apparatus 100, and the printed media M are stacked thereon.

Note that the configuration of the image forming apparatus 100 described above is merely an example, and the apparatus to which the medium M is supplied by the medium supplying apparatus 1 is not particularly limited, and may be an apparatus that does not include the printing unit 130 .

FIG. 3 is a diagram showing a control configuration of the medium feeding device 1. As shown in FIG.
FIG. 4 is a perspective view showing the medium feeding device 1 with the drawer section 40 pulled out.

5 to 7 are front views for explaining the operation of the medium feeding device 1. FIG.
8 and 9 are perspective views showing the feeding section 20 and the medium height detection section 50. FIG.

FIG. 10 is a perspective view showing the medium height detector 50. As shown in FIG.
As shown in FIGS. 2 to 4, the medium supply device 1 includes a supply tray 10, a feeding section 20, a housing 30, a drawer section 40, a medium height detection section 50, a control section 61, a storage unit 62, interface unit 63, elevation drive unit 70, three tray height detection sensors 81 (tray height detection sensors 81a, 81b, 81c shown in FIGS. 5 to 7), and medium size detection sensor 82 , and a medium presence/absence detection sensor 83 .

As shown in FIG. 2, media M are stacked on the supply tray 10 . As an example, the supply tray 10 is suspended in the drawer section 40 by four linear members (for example, wires) (not shown) that are examples of suspension members. It is possible to move up and down by winding and unwinding the linear member.

As shown in FIG. 4, the supply tray 10 is arranged to be able to be pulled out from the housing 30 in the pull-out direction D2 (forward direction) together with the drawer portion 40 . As will be described later, as the drawer portion 40 is pulled out, the drive path for transmitting power from the elevation drive portion 70 to the supply tray 10 (drawer portion 40) is cut off, thereby preventing the supply tray 10 from suddenly dropping. For this reason, the unwinding speed of the four linear members is limited by a damping device such as a rotary damper.

As shown in FIGS. 5 to 7 and FIG. 13, which will be described later, a detection piece whose presence or absence is detected by three tray height detection sensors 81 (81a, 81b, 81c), which will be described later, is provided on the front left portion of the supply tray 10. 11 is provided.

As shown in FIGS. 5 to 7, the delivery section 20 has delivery rollers 21 and 22, a separating plate 23, and a guide plate 24. As shown in FIGS. In addition, as shown in FIGS. 8 and 9, the feeding section 20 further has a roller shaft 25 and a transmission belt 26. As shown in FIGS. 8, 9, 13, and 14, only a part of the rear side of the roller shaft 25 is shown. Further, the transmission belt 26 is illustrated only in FIGS. 8 and 9. FIG.

As shown in FIGS. 5 to 7, one delivery roller 21 among delivery rollers 21 and 22 delivers the uppermost medium M1 stacked on the supply tray 10, and the other delivery roller 22 is operated by the delivery roller 21. The fed medium M is transported toward the image forming apparatus 100 in the feeding direction D1 (rightward). The delivery rollers 21 and 22 are an example of a delivery member, but a delivery belt or the like may be used as the delivery member.

The separating plate 23 is arranged to face the delivery roller 22 and separates the media M one by one between the delivery roller 22 and the delivery roller 22 . As a result, the uppermost medium M1 and the second and subsequent mediums M are separated. It is preferable that at least the surface of the separating plate 23 that contacts the medium M is made of rubber so that the medium M generates frictional resistance. Further, the separating plate 23 is preferably moved in a direction away from the delivery roller 22 in conjunction with the operation of pulling out the drawer portion 40 in the drawer direction D2.

The guide plate 24 is, for example, an L-shaped plate member when viewed from the front, and guides the medium M delivered in the delivery direction D<b>1 by the delivery roller 22 . The guide plate 24 is provided with a through hole (not shown) through which the separating plate 23 is passed.

A roller shaft 25 shown in FIGS. 8 and 9 is the central axis of rotation of the delivery roller 22 .
The transmission belt 26 is stretched over a pulley provided coaxially with the delivery roller 21 and a pulley provided coaxially with the delivery roller 22 . The delivery rollers 21 and 22 are rotated by being driven by a delivery motor, which is an example of delivery driving means (actuator) not shown.

As shown in later-described FIGS. 13 and 14 , the housing 30 has a housing inner plate 31 . The housing internal plate 31 is provided in a region that does not interfere with the drawer portion 40 that is drawn out in the drawer direction D2.

As shown in FIG. 4 , the drawer portion 40 has a regulation plate 41 , side fences 42 and 43 and an end fence 44 .

The regulating plate 41 regulates the position of the downstream end of the media M stacked on the supply tray 10 in the delivery direction D1.

The side fences 42 and 43 are arranged to face each other, and regulate the positions of the ends of the media M stacked on the supply tray 10 in the width direction (front-rear direction) perpendicular to the delivery direction D1.

The end fence 44 regulates the position of the upstream end of the media M stacked on the supply tray 10 in the feeding direction D1. , is rotatably arranged in an open position so as not to hinder the replenishment of the medium M. As shown in FIG.

As shown in FIGS. 5 to 10, the medium height detection section 50 has a pressed section 51 and a sensor 52, and detects that the top medium M1 is at the supply height. This supply height is, for example, a height at which the feeding unit 20 can feed the uppermost medium M1.

The pressed portion 51 is, for example, an L-shaped arm rotatable about the front-rear direction as a central axis of rotation. A detected portion 51b whose presence or absence is detected by is provided. Since the contact portion 51a contacts the medium M, it is preferable that the contact portion 51a be a low-friction member or a roller member so as not to cause a resistance to transport of the medium M.

The pressed portion 51 is pressed upward at the contact portion 51a by the downstream portion M1a of the uppermost medium M1 shown in FIG. As a result, the pressed portion 51 rotates counterclockwise in FIG. Note that the downstream portion M1a of the uppermost medium M1 in the delivery direction D1 is the downstream portion when the uppermost medium M1 is divided into the downstream portion M1a and the upstream portion across the center in the delivery direction D1. M1a. However, the abutment portion 51a is preferably pressed upward at the end portion of the uppermost medium M1 on the downstream side in the feeding direction D1. In addition, although FIG. 5 illustrates that the delivery roller 21 and the top medium M1 are not in contact with each other, when the top medium M1 is delivered by the delivery roller 21, the delivery roller 21 and the top medium M1 are not in contact with each other. It is in contact with medium M1.

The sensor 52 is, for example, a C-shaped (U-shaped) photosensor in plan view into which the detected portion 51b is inserted, and detects the presence or absence of the pressed portion 51 (detected portion 51b). The medium height detection unit 50 detects that the height of the uppermost medium M1 is at the supply height by the sensor 52 detecting the pressed portion 51, and outputs an ON signal. On the other hand, when the sensor 52 does not detect the pressed portion 51, the medium height detection portion 50 detects that the height of the uppermost medium M1 is not at the supply height, and outputs an OFF signal.

The medium height detection unit 50 preferably has the above-described pressed portion 51. For example, the medium height detection unit 50 irradiates the detection light in the horizontal direction and detects that the height of the uppermost medium M1 is at the supply height. Therefore, the pressed portion 51 may not be provided.

The controller 61 shown in FIG. 3 preferably has a processor (for example, CPU: Central Processing Unit) that functions as an arithmetic processing device that controls the operation of the entire medium feeding device 1 . Note that when the medium feeding device 1 is provided integrally with the image forming apparatus 100 as described above, the control section of the image forming apparatus 100 may also serve as the control section 61 of the medium feeding device 1 .

Although details will be described later, the control unit 61 controls the elevation driving unit 70 to lower the supply tray 10 after the feeding operation of the medium M by the feeding unit 20 is completed (for example, after the print job is completed). In addition, the control unit 61 determines that the time from when the supply tray 10 starts to descend to when the medium height detection unit 50 no longer detects that the top medium M1 is at the supply height is the specified time. If it is longer than , the elevation drive unit 70 is controlled to increase the amount of descent of the supply tray 10 .

The storage unit 62 is, for example, a ROM (Read Only Memory), which is a read-only semiconductor memory in which a predetermined control program is recorded in advance, and a work storage area as necessary when the processor executes various control programs. It has a random access memory (RAM), which is a semiconductor memory that can be written and read at any time, and the like.

The interface unit 63 exchanges various information with the image forming apparatus 100 and other apparatuses.

The elevation drive unit 70 is, for example, an actuator such as a motor that raises and lowers the supply tray 10 by winding and unwinding the four linear members described above. The elevation drive unit 70 is connected via a coupling (shaft joint) so that the drive path for transmitting power from the elevation drive unit 70 to the supply tray 10 (drawer unit 40) is cut off as the drawer unit 40 is pulled out. It is connected to the drawer part 40 .

As described above, the lifting drive unit 70 is controlled by the control unit 61 to lower the supply tray 10 after the feeding operation of the medium M by the feeding unit 20 is completed. In addition, when the number of media M stacked on the supply tray 10 decreases as the feeding unit 20 feeds out the uppermost medium M1, the elevation driving unit 70 moves the height of several media M, for example. It is controlled by the controller 61 to intermittently raise the supply tray 10 .

As shown in FIGS. 5 to 7 and FIG. 13 to be described later, the three tray height detection sensors 81 (81a, 81b, 81c) are arranged in the vertical direction. 11 is detected. The tray height detection sensor 81 (81a, 81b, 81c) is, for example, a C-shaped (U-shaped) photosensor into which the detected piece 11 is inserted. Note that the tray height detection sensor 81 (81a, 81b, 81c) is an example of a tray height detection unit that detects the height of the supply tray 10. FIG.

The controller 61 can determine the height of the supply tray 10 based on the output signals of the three tray height detection sensors 81 (81a, 81b, 81c). Therefore, when the medium height detection unit 50 detects that the top medium M1 is at the supply height, the control unit 61 controls the three tray height detection sensors 81 (81a, 81b, 81c), the remaining amount of the medium M can be determined. Since the remaining amount of media M corresponds to the height of all the media M stacked on the supply tray 10, even if the height of the media M is the same, when the media M are thick paper, the number of media M is larger than when the media M is thin paper. will be less.

The medium size detection sensor 82 shown in FIG. 3 is a sensor for detecting the size of the medium M loaded on the supply tray 10. For example, the medium size detection sensor 82 is arranged on the upper surface of the supply tray 10 to detect the presence or absence of the medium M. As the number of medium size detection sensors 82 increases, more sizes and orientations of the medium M can be determined. Note that the medium M is oriented vertically in parallel with the feeding D1, or horizontally perpendicular to the feeding D1.

The medium presence/absence detection sensor 83 is a sensor for detecting whether or not the medium M is stacked on the supply tray 10, and is arranged, for example, on the upper surface of the supply tray 10 on the downstream side in the delivery direction D1.

By the way, for example, when the medium M is fed out at high speed, or when the medium M is fed out continuously, the other media M along with the uppermost medium M1 gradually deviate in the feeding direction D1. , after the feeding operation of the medium M is completed (for example, after the print job is completed), one or a plurality of media M including the uppermost medium M1 are ejected from the supply tray 10, and the feeding roller 22 and the separating plate are ejected. 23. Therefore, the control unit 61 performs the processing of the flowchart shown in FIG.

FIG. 12 is a flow chart for explaining the processing in this embodiment.
As shown in FIG. 12, first, the control unit 61 determines whether or not the feeding operation of the medium M (for example, the feeding operation of the instruction corresponding to the print job acquired from the image forming apparatus 100) has ended (step S1). The control unit 61 repeats this determination process until the feeding operation of the medium M is completed.

When the feeding operation of the medium M is completed (step S1: YES), the control unit 61 controls the elevation driving unit 70 so as to lower the supply tray 10 shown in FIG. 5 by a height h1 as shown in FIG. The tray 10 starts to descend (step S2).

As shown in FIG. 11, the control unit 61 determines the amount of descent of the supply tray 10 based on the remaining amount of the medium M and the size (for example, "A4" or "B5" smaller than A4). h1 should be adjusted. For example, as the remaining amount of the medium M increases or the size of the medium M increases, the weight of the medium M loaded on the supply tray 10 increases. Even if the unwinding speed of the supply tray 10 is limited, the lowering speed of the supply tray 10 is increased. Therefore, it can be said that the protrusion of the medium M in the feeding direction D1 is easily eliminated. Therefore, the smaller the remaining amount of the medium M or the smaller the size of the medium M, the easier it is to prevent the medium M from jumping out in the feeding direction D1 by increasing the amount of descent (height h1) of the supply tray 10. do it.

In addition, when the longitudinal direction of the medium M is vertical parallel to the feeding D1, the protrusion is more difficult to eliminate than when the medium M is horizontal perpendicular to the feeding D1. h1) should be increased. In this way, the control unit 61 adjusts the lowering amount (height h1) of the supply tray 10 based on at least one of the remaining amount, size, and orientation of the media M stacked on the supply tray 10, It is preferable to control the elevation driving unit 70 .

Next, the control unit 61 detects that the height of the uppermost medium M1 is at the supply height by the medium height detection unit 50 within a specified time after the start of the descent of the supply tray 10. It is determined whether the state (ON signal output) has changed to the undetected state (OFF signal output) (step S3).

Here, when the uppermost medium M1 is positioned on the supply tray 10 without protruding in the feeding direction D1 as shown in FIG. Since the uppermost medium M1 also descends together with the supply tray 10, the contact portion 51a descends by its own weight or the biasing force of the biasing mechanism (not shown). Therefore, immediately after the supply tray 10 starts to descend (within a specified time), the medium height detection unit 50 stops detecting that the top medium M1 is at the supply height (step S3: YES). In this case, the control unit 61 terminates the processing shown in FIG. It should be noted that the above-mentioned prescribed time is such that, for example, when the top medium M1 is not sandwiched between the delivery roller 22 and the separating plate 23, it is detected that the top medium M1 is at the supply height. It is preferable to use the time until it runs out or the time that is longer than this time.

As shown in FIG. 6, when the uppermost medium M1 protrudes in the delivery direction D1 and is sandwiched between the delivery roller 22 and the separation plate 23, even if the supply tray 10 descends, the uppermost medium is M1 does not descend integrally with the supply tray 10. - 特許庁Therefore, the contact portion 51a descends with a time delay or a speed slower than the supply tray 10. As shown in FIG. Therefore, the time from when the supply tray 10 starts to descend to when the medium height detector 50 no longer detects that the uppermost medium M1 is at the supply height is longer than the specified time. longer (step S3: NO).

In this case, as shown in FIG. 7, the controller 61 sets the amount of descent of the supply tray 10 to a height h2 (e.g. , and the amount of descent of sizes A4' and B5' shown in FIG. 11) (step S4). Then, the control unit 61 terminates the processing shown in FIG. 12 .

By increasing the amount of descent of the supply tray 10 in this way, the medium M ejected from the supply tray 10 in the feeding direction D1 is easily pulled downward due to the air pressure difference between the medium M on the supply tray 10 and the ejected medium. M falls back onto the supply tray 10 .

The specified time is shorter than, for example, the time required for the supply tray 10 to descend by the height h1. It may be determined whether the height of M1 is no longer detected to be at the supply height. In this case, the specified time can be said to be the time until the supply tray 10 descends by the height h1.

In addition, if the time until it is no longer detected that the top medium M1 is at the supply height is longer than the specified time, the control unit 61 may notify the user that the medium M has popped out. . This notification to the user includes, for example, lighting or blinking of a status display lamp (not shown), display on a display panel (not shown) of the image forming apparatus 100, and audio output by an audio output unit (not shown). Note that the notification to the image forming apparatus 100 may be performed instead of or together with the notification to the user.

In the above description, the control unit 61 adjusts the lowering amount of the height h1 of the supply tray 10 based on at least one of the remaining amount, the size, and the orientation of the media M stacked on the supply tray 10. was explained, but only the difference between the height h2 and the height h1, that is, the increase in the amount of descent (height h2 - height h1), or the height h1 and the increment in the amount of descent (height h2 - Both heights h1) may be adjusted based on at least one of the remaining amount of media M loaded in the supply tray 10, size and orientation.

As described above, by lowering the supply tray 10 by the height h1 and further lowering it to the height h2 according to the situation, the uppermost medium M1 pops out from the supply tray 10 in the feeding direction D1 as shown in FIG. The drawer portion 40 can be pulled out in the pull-out direction D2 in a state in which it is not pulled out.

On the other hand, when the uppermost medium M1 protrudes from the supply tray 10 in the drawing direction D1 as shown in FIG. contact with, tear or bend. When the drawer portion 40 is pulled out, the drive path is cut and the supply tray 10 drops. Since the unwinding speed of the shaped member is limited, the supply tray 10 suddenly moves in a very short period of time from when the drawer 40 starts to draw until the ejected medium M contacts the housing inner plate 31. It is difficult to eliminate the popping out of the medium M without descending.

Regardless of the result of detection by the medium height detection unit 50, the supply tray 10 is lowered in one step to the lowering amount that can eliminate the state in which the uppermost medium M1 protrudes in the feeding direction D1 as shown in FIG. It is also possible to control the

In the embodiment described above, the medium feeding device 1 includes the feeding tray 10 on which the medium M is stacked, the feeding section 20 for feeding the uppermost medium M1 stacked on the feeding tray 10, and the feeding tray 10. A lifting drive unit 70 for raising and lowering, a medium height detection unit 50 for detecting that the height of the uppermost medium M1 is at the supply height, and after the feeding operation of the medium M by the feeding unit 20 is completed, the supply tray and a control unit 61 that controls the elevation driving unit 70 so as to lower the device 10 . The control unit 61 sets the time from when the supply tray 10 starts to descend until the medium height detection unit 50 stops detecting that the uppermost medium M1 is at the supply height to be longer than a specified time. If it is longer, the lift drive unit 70 is controlled so that the amount of descent of the supply tray 10 is increased from the height h1 to the height h2.

By lowering the supply tray 10 in this manner, the uppermost medium M1 stacked on the supply tray 10 jumps out from the supply tray 10, for example, between the supply roller 22 and the separation plate 23 after the supply operation is completed. In this case, the uppermost medium M1 (the entire uppermost medium M1) can be returned onto the supply tray 10 without arranging a new part. Furthermore, the control unit 61 controls the height of the medium M to the supply tray 10 according to the time from when the supply tray 10 starts to descend to when it is no longer detected that the height of the uppermost medium M1 is at the supply height. It is determined whether the supply tray 10 protrudes from above, and only when it is determined that the supply tray 10 protrudes, the lowering amount of the supply tray 10 is further increased (increased from the height h1 to the height h2). Therefore, compared to the case where the amount of descent of the supply tray 10 is increased each time, the amount of descent can be suppressed. As a result, it is possible to shorten the time until the drawer portion 40 can be pulled out after the end of the feeding operation, so that it is possible to avoid the deterioration of the user's workability.

Therefore, according to the present embodiment, the medium M ejected from the supply tray 10 can be returned to the supply tray 10 with a simple configuration while suppressing deterioration of user's workability.

In addition, since the medium M ejected from the supply tray 10 can be returned to the supply tray 10 after the feeding operation is completed, when the feeding operation is restarted without the drawer section 40 being pulled out, the ejection of the medium M cannot be prevented. It is also possible to avoid double feeding of the medium M. Further, by lowering the supply tray 10 after the end of the feeding operation, the driving path of the coupling (shaft joint) for transmitting the power from the elevation driving unit 70 to the supply tray 10 is cut off as the drawer unit 40 is pulled out. When the supply tray 10 drops, the amount of descent of the supply tray 10 to the lower end can be reduced, so the impact of the drop of the supply tray 10 can be suppressed. In addition, by further increasing the amount of descent of the supply tray 10 only when it can be determined that the medium M has protruded, the drawer section 40 can be pulled out more than when the amount of descent of the supply tray 10 is increased each time. It is possible to shorten the time for raising the supply tray 10 when the feeding operation is resumed without being pulled. Assuming that the medium M protrudes from the supply tray 10, the opening of the component housing 30 is enlarged or the part ( For example, the strength (rigidity) of the housing 30 can be ensured, and the degree of freedom in design can be increased compared to a mode in which the arrangement of power transmission mechanisms such as gears, pulleys, and belts is restricted. The device 1 can have a simple configuration.

In addition, in the present embodiment, the control unit 61 adjusts the amount of descent of the supply tray 10 based on at least one of the remaining amount, size, and orientation of the media M stacked on the supply tray 10. It controls the drive unit 70 . As a result, it is possible to adjust the amount of descent of the supply tray 10 according to the condition of the remaining amount of the medium M, the size, and the orientation of the medium M, which is difficult to solve by lowering the supply tray 10. Therefore, the lowering amount of the supply tray 10 can be adjusted more reliably. In addition, the medium M ejected from the supply tray 10 can be returned to the supply tray 10. - 特許庁

In the present embodiment, the medium height detection unit 50 includes a pressed portion 51 that is pressed upward by a downstream portion M1a of the uppermost medium M1 in the feeding direction D1 by the feeding portion 20, and and a sensor 52 for detecting the presence or absence of the portion 51 . Therefore, when the uppermost medium M1 jumps out of the supply tray 10 and is sandwiched between the delivery roller 22 and the separation plate 23, the uppermost medium M1 is difficult to descend as the supply tray 10 descends. In the portion M1a, it is possible to more reliably determine whether or not the medium M has protruded.

It should be noted that the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying constituent elements without departing from the scope of the present invention at the implementation stage. Also, various inventions can be formed by appropriate combinations of the plurality of constituent elements disclosed in the above-described embodiments. For example, all the components shown in the embodiments may be combined as appropriate. It goes without saying that various modifications and applications are possible without departing from the spirit of the invention. The invention described in the scope of claims at the time of filing of the present application will be additionally described below.

[Appendix 1]
a supply tray on which media are loaded;
a feeding unit for feeding the uppermost medium stacked on the supply tray;
an elevation driving unit for raising and lowering the supply tray;
a medium height detection unit that detects that the height of the uppermost medium is at the supply height;
a control unit that controls the elevation drive unit so as to lower the supply tray after the feeding operation of the medium by the feeding unit is completed;
The control unit controls the time from when the supply tray starts to descend to when the medium height detection unit no longer detects that the height of the uppermost medium is at the supply height is longer than a specified time. and controlling the elevation drive unit to increase the amount of descent of the supply tray when the medium supply tray is too long.

[Appendix 2]
The control unit adjusts the amount of descent of the supply tray based on at least one of the remaining amount, size, and orientation of the media stacked on the supply tray, and controls the elevation drive unit. The medium supply device according to appendix 1, characterized by:

[Appendix 3]
The medium height detection unit has a pressed portion that is pressed upward by a downstream portion of the uppermost medium in the feeding direction of the feeding unit, and a sensor that detects the presence or absence of the pressed portion. 3. The medium supply device according to appendix 1 or 2, characterized by:

Reference Signs List 1 medium supply device 10 supply tray 11 piece to be detected 20 delivery portion 21, 22 delivery roller 23 separation plate 24 guide plate 25 roller shaft 26 transmission belt 30 housing 31 housing internal plate 40 drawer portion 41 regulation plate 42, 43 side fence 44 End fence 50 Medium height detector 51 Pressed part 51a Contact part 51b Detected part 52 Sensor 61 Control part 62 Storage part 63 Interface part 70 Elevation drive part 81 (81a, 81b, 81c) Tray height detection sensor 82 Medium Size Detection Sensor 83 Medium Presence/Absence Detection Sensor 100 Image Forming Apparatus 111 First Paper Feed Tray 112 Second Paper Feed Tray 113 Third Paper Feed Tray 121 Conveyance Path 121a Reverse Path 122 Conveyance Roller 130 Print Section 140 Adsorption Conveyance Section 150 Paper discharge tray D1 Feeding direction D2 Pulling direction M Medium M1 Uppermost medium M1a Downstream portion

Claims (3)

a supply tray on which media are loaded;
a feeding unit for feeding the uppermost medium stacked on the supply tray;
an elevation driving unit for raising and lowering the supply tray;
a medium height detection unit that detects that the height of the uppermost medium is at the supply height;
a control unit that controls the elevation drive unit so as to lower the supply tray after the feeding operation of the medium by the feeding unit is completed;
The control unit controls the time from when the supply tray starts to descend to when the medium height detection unit no longer detects that the height of the uppermost medium is at the supply height is longer than a specified time. and controlling the elevation drive unit to increase the amount of descent of the supply tray when the medium supply tray is too long. The control unit adjusts the amount of descent of the supply tray based on at least one of the remaining amount, size, and orientation of the media stacked on the supply tray, and controls the elevation drive unit. 2. The medium feeding device according to claim 1, characterized by: The medium height detection unit has a pressed portion that is pressed upward by a downstream portion of the uppermost medium in the feeding direction of the feeding unit, and a sensor that detects the presence or absence of the pressed portion. 3. The medium feeding device according to claim 1 or 2, characterized by:

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