JP7337325B2 - Media feeder - Google Patents

Description

TECHNICAL FIELD The present invention relates to a medium supply device that includes a vertically movable supply tray on which media are stacked.

Conventionally, as a paper feeding device for detecting double feeding of paper, there has been proposed a paper feeding device equipped with detection means for simultaneously detecting the height of paper stacked on a mounting table and the double feeding of paper when paper is fed ( For example, see Patent Document 1). The detecting means rotatably supports an arm whose tip is in contact with the uppermost sheet of paper, and detects a change in the thickness of one sheet of paper by detecting the rotation angle of this arm.

JP-A-7-61649

By the way, in the image forming apparatus, the number of media stacked on the supply tray decreases as media such as paper are fed out. Therefore, based on the detection result of the decrease in the number of media, control is performed to raise the supply tray.

In addition, for example, when the feeding operation is performed at high speed for high-speed printing, etc., or when the feeding operation of a plurality of media is continuously performed, the other media are fed in the feeding direction together with the uppermost medium to be fed. It may shift gradually. As a result, if the medium erroneously enters in the feeding direction, the medium will be caught between, for example, the pickup roller and the separation plate in the feeding section that feeds the medium.

When a plurality of media are caught in the feeding section in this way, in a mode in which a decrease in the number of media is detected while being in contact with the uppermost medium, the number of media is counted until all of the plurality of media caught in the feeding section are fed out. Decrease is no longer detected. As a result, the feed tray rises slowly, causing empty feeding of the medium.

As described above, a paper feeder equipped with a detection means for detecting a change in the thickness of a single sheet of paper requires a member such as an arm, and extremely high-precision detection means. Complicated.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a medium feeder which has a simple structure and is capable of preventing the medium from being fed empty.

In one aspect, the medium supply device includes a vertically movable supply tray on which the medium is stacked, a first supply member for supplying the uppermost medium loaded on the supply tray, and the first supply unit for supplying the medium in the supply direction. a second feeding member spaced apart from the first feeding member and arranged above the first feeding member for feeding the uppermost medium; and the first feeding member and the second feeding member in the feeding direction. a tension detection unit for detecting that the uppermost medium is stretched between the supply trays; and when the tension detection unit detects that the uppermost medium is stretched, the supply tray is and a control unit that controls not to lift the medium, and the control unit controls the tension detection unit while the uppermost medium is being delivered under a predetermined condition by the first delivery member and the second delivery member. When it is continuously detected that the uppermost medium is stretched, control is performed to raise the supply tray.

According to the above aspect, it is possible to prevent the medium from being air-fed with a simple configuration.

1 is a perspective view showing a medium feeding device and an image forming device according to a first embodiment; FIG. 1 is a front view showing internal structures of a medium feeding device and an image forming apparatus according to a first embodiment; FIG. FIG. 4 is a perspective view showing the medium feeding device in a state where the drawer portion is pulled out according to the first embodiment; 4 is a diagram showing a control configuration of the medium feeding device according to the first embodiment; FIG. FIG. 2 is a front view (Part 1) showing the internal structure of the medium feeding device according to the first embodiment; 2 is a front view (part 2) showing the internal structure of the medium feeding device according to the first embodiment; FIG. 3 is a front view (part 3) showing the internal structure of the medium feeding device according to the first embodiment; FIG. 4 is a front view (part 4) showing the internal structure of the medium feeding device according to the first embodiment; FIG. FIG. 11 is a front view (part 1) showing the internal structure of the medium feeding device according to the second embodiment; FIG. 11 is a front view (part 2) showing the internal structure of the medium feeding device according to the second embodiment;

A medium feeding device 1 according to a first embodiment and a medium feeding device 2 according to a second embodiment of the present invention will be described below with reference to the drawings.

<First embodiment>
FIG. 1 is a perspective view showing a medium feeding device 1 and an image forming device 100. FIG.

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. 3 and 5 to 10 to be described later, the direction D1 of feeding the medium M is to the right, and the direction D2 of the drawing unit 40 is to the front. 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, paper (sheet paper).

Here, 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, a plurality of transport rollers 122, a printing 130 , suction transport section 140 , discharge tray 150 , and operation panel 160 .

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 suction transport unit 140 transports the medium M that has been sucked by the transport 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.

The operation panel 160 shown in FIG. 2 has a display section 161 and an operation section 162 . 1, illustration of the operation panel 160 is omitted.

The display unit 161 is a display that displays various information such as a display screen for user input operations. In addition, when the display unit 161 has a touch panel, it can also function as an input unit.

The operation unit 162 is an example of an input unit that receives various types of operation information input by the user.

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

5 to 8 are front views showing the internal structure of the medium feeding device 1. FIG.
As shown in FIGS. 2 to 8, the medium supply device 1 includes a supply tray 10, a feeding unit 20, a housing 30, a drawer unit 40, a tension detection unit 50, a control unit 61, and a storage unit. 62 , an interface unit 63 , an elevation drive unit 70 and a medium passage detection sensor 80 .

As an example, as shown in FIG. 3, the supply tray 10 is arranged to be able to be pulled out from the housing 30 together with the drawer portion 40 in the pull-out direction D2 (forward direction). The supply tray 10 is suspended by four linear members (for example, wires) (not shown), which are examples of suspension members, in the drawer section 40. It can be raised and lowered by winding and unwinding the member.

Further, when the drive path for transmitting power from the lifting drive unit 70 to the supply tray 10 is cut off as the drawer unit 40 is pulled out, a shock absorber such as a rotary damper is used to prevent the supply tray 10 from suddenly falling. It is preferable that the unwinding speed of the four linear members is restricted by the device. Note that the supply tray 10 is not limited to being pulled out together with the drawer portion 40 .

As shown in FIG. 5, media M are stacked on the supply tray 10 . The supply tray 10 can be moved up and down by being driven by an elevation drive section 70, which will be described later.

The delivery unit 20 has delivery rollers 21 and 22 , a separating plate 23 and a guide plate 24 .

Of the delivery rollers 21 and 22 , the delivery roller 21 on the upstream side in the delivery direction D<b>1 (right direction) is a scraper roller that delivers the uppermost medium M<b>1 stacked on the supply tray 10 . The delivery roller 22 on the downstream side in the delivery direction D1 is a pickup roller that conveys the medium M delivered by the delivery roller 21 toward the image forming apparatus 100 in the delivery direction D1.

Further, the delivery rollers 21 and 22 are arranged in plural in the width direction (front-rear direction) perpendicular to the delivery direction D1 of the medium M, for example. A stretch detector 50 , which will be described later, is preferably arranged between the plurality of delivery rollers 22 . Note that the delivery roller 21 is an example of a first delivery member that delivers the uppermost medium M1. Further, the delivery roller 22 is an example of a second delivery member that is arranged in the delivery direction D1 of the medium M with a gap from the delivery roller 21 and is arranged above the delivery roller 21 to deliver the uppermost medium M1. . As the first delivery member and the second delivery member, a pulley or the like on which a delivery belt is stretched may be used.

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 pull-out portion 40 in the pull-out direction D2 (forward direction).

The guide plate 24 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.

As shown in FIGS. 2 and 3, the housing 30 accommodates the supply tray 10, the delivery section 20, the drawer section 40, and the like. As shown in FIG. 3, an openable and closable upper door 31 is provided on the upper surface of the housing 30 . When the upper door 31 is opened or the drawer portion 40 is pulled out, the operation of feeding out the medium M in the medium feeding device 1 may be stopped by operating the interlock switch.

As shown in FIG. 3 , 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 8, the tension detector 50 has a pushed-up part 51 and a tension detection sensor 52. As shown in FIGS. The tension detection unit 50 detects that the uppermost medium M1 is stretched between the delivery rollers 21 and 22 in the delivery direction D1, that is, is in a state of tension (supply height). do.

The pushed-up part 51 has an arm 51a, a rotating shaft member 51b, a roller 51c, and a detected piece 51d.

The arm 51a is rotatably arranged around a rotating shaft member 51b extending in the front-rear direction.

The roller 51c is rotatably arranged at the end of the arm 51a, and is pushed up by the uppermost medium M1 between the delivery rollers 21 and 22 in the delivery direction D1 (right direction). As a result, the pushed-up portion 51 rotates clockwise in FIGS. 5 to 8 with the rotary shaft member 51b as the central axis of rotation. On the other hand, when the roller 51c is not pushed up by the uppermost medium M1, the pushed-up portion 51 rotates counterclockwise by its own weight with the rotating shaft member 51b as the rotation center axis, as shown in FIG.

The piece to be detected 51d is provided at an end portion of the portion to be pushed up 51 that is different from the roller 51c.

The tension detection sensor 52 has a U-shape (U-shape) opening downward. The tension detection sensor 52 indicates that the top medium M1 is stretched by blocking the detection light by the detection piece 51d pushed up by the top medium M1 as described above. An ON signal (see FIGS. 5, 6, and 8) is output. In addition, when the detection light is not blocked by the detected piece 51d which is not pushed up by the uppermost medium M1 as described above, the tension detection sensor 52 indicates that the uppermost medium M1 is not suspended. An OFF signal (see FIG. 7) is output. In this way, the tension detector 50 can detect that the uppermost medium M1 is stretched between the delivery rollers 21 and 22 in the delivery direction D1.

Although it is desirable that the suspension detection unit 50 has the above-described pushed-up portion 51, it may detect that the uppermost medium M1 is suspended by irradiating the detection light in the horizontal direction, for example. , the push-up part 51 may not be provided.

The control unit 61 shown in FIG. 4 preferably has a processor (for example, CPU: Central Processing Unit) that functions as an arithmetic processing unit that controls the operation of the entire medium feeding device 1 . 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 .

The control unit 61 performs control so that the supply tray 10 is not lifted when the suspension detection unit 50 detects that the uppermost medium M1 is suspended. For example, after the tension detection unit 50 detects that the uppermost medium M1 is stretched, the medium M stacked on the supply tray 10 is removed as the uppermost medium M1 is fed out by the feeding unit 20. As the number decreases, the tension detection sensor 52 outputs an OFF signal indicating that the uppermost medium M1 is not tensioned. The control unit 61 controls the elevation driving unit 70 to raise the supply tray 10 based on the OFF signal output from the tension detection sensor 52 .

Further, although the details will be described later, the control unit 61 causes the feeding rollers 21 and 22 to feed out the uppermost medium M1 under a predetermined condition (for example, a specified number of sheets (for example, three sheets) or more) while the medium M1 is being stretched. When the stack detection unit 50 continuously detects that the uppermost medium M1 is stretched, control is performed to raise 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 to the supply tray 10 via a coupling (shaft joint) so that the drive path for transmitting power from the elevation drive unit 70 to the supply tray 10 is cut off as the drawer unit 40 is pulled out. It is

The medium passing detection sensor 80 is arranged downstream of the delivery roller 22 and the separation plate 23 in the delivery direction D1 (rightward direction). The medium passage detection sensor 80 is, for example, a pair of optical sensors and detects the passage of the medium M.

The feeding operation of the medium M will be described below with reference to FIGS. 5 to 8. FIG.
First, as shown in FIG. 5, in a state in which only one medium M (top medium M1) enters between the delivery roller 22 and the separation plate 23 and is delivered, one medium is then Each time M is fed out, the pushed-up portion 51 is no longer pushed up by the uppermost medium M1, and the tension detection sensor 52 outputs an OFF signal indicating that the uppermost medium M1 is not tensioned. The control unit 61 controls the elevation driving unit 70 to raise the supply tray 10 based on the change from the ON signal to the OFF signal of the tension detection sensor 52 . This lifting control is changed according to the thickness of the medium M. For example, in the case of thick paper, the feed tray 10 is raised by one change from the ON signal to the OFF signal of the tension detection sensor 52, and in the case of thin paper, the feed tray 10 is raised. 3, the supply tray 10 is controlled to be lifted when the tension detection sensor 52 changes from the ON signal to the OFF signal three times. The thickness information of the medium M can be obtained from a paper type setting device (an example of a medium type setting device) (not shown) provided in the medium feeding device. an example of a device) may be provided.

On the other hand, if the medium M is a medium that is likely to be multi-fed, multiple sheets of the medium M enter between the delivery roller 22 and the separating plate 23 as shown in FIG. In this case, the medium M that has entered between the delivery roller 22 and the separation plate 23 is tensioned with the outer peripheral surface of the delivery roller 21 to push up the roller 51c. As a result, the tension detection sensor 52 outputs an ON signal indicating that the uppermost medium M1 is stretched until the plurality of media M that have entered between the feeding roller 22 and the separating plate 23 are fed out. Therefore, the control unit 61 does not perform lift control of the supply tray 10 .

Therefore, as shown in FIG. 7, a plurality of media M that have entered between the delivery roller 22 and the separation plate 23 are delivered, and the tension detection sensor 52 detects that the uppermost medium M1 is not suspended. is output, a gap in the height direction is generated between the uppermost medium M1 and the delivery roller 21 . As a result, the supply tray 10 is not lifted in time for the feeding operation of the feeding section 20, resulting in empty feeding.

Therefore, the control unit 61 controls the prescribed number of media M (for example, 1 or 2) larger than the number of media M to be delivered by the delivery rollers 21 and 22 before the tension detection sensor 52 outputs the OFF signal. If the tension detection sensor 52 continuously outputs the ON signal while three or more media M are fed out, control is performed to raise the supply tray 10 in anticipation. The lifting timing and lifting amount of the supply tray 10 in this control may be determined based on a predetermined fixed value, or may be determined to be the same as before the supply tray 10 is lifted. good too. It should be noted that the lift timing and lift amount before the feed tray 10 is lifted is not always constant, so the control unit 61 preferably obtains an average value for a predetermined period. Further, the control section 61 may determine the prescribed number of sheets based on the rising timing of the predetermined period. That is, the specified number may be a variable number instead of a fixed number. Note that the control unit 61 may determine whether or not a predetermined number of media M or more have been fed based on the detection result of the medium passage detection sensor 80, for example.

As shown in FIG. 6, the control unit 61 performs the control to raise the supply tray 10 in anticipation, so that even when a plurality of media M are entering between the delivery roller 22 and the separating plate 23 as shown in FIG. , the supply tray 10 rises as shown in FIG. As a result, unlike the example shown in FIG. 7, the supply tray 10 rises in time for the feeding operation of the feeding section 20, thereby preventing empty feeding.

It should be noted that since the rigidity and degree of adhesion of the media M differ depending on the type, it is difficult to determine the ease with which the media M enter between the delivery roller 22 and the separation plate 23, and thus the ease with which the media M are fed in multiples. is. However, as in the first embodiment, while the feeding unit 20 is feeding the uppermost medium M1 by the specified number or more, the tension detection unit 50 may detect that the uppermost medium M1 is being stretched. If it is continuously detected, the control unit 61 can also determine that the situation is likely to cause double feeding. The control unit 61 performs control to raise the supply tray 10 in anticipation as described above in this situation in which multiple sheets are likely to be fed.

In the first embodiment described above, the medium supply device 1 includes an example of a vertically movable supply tray 10 on which the medium M is stacked and a first supply member that supplies the uppermost medium M1 stacked on the supply tray 10. and a delivery roller 21 that is an example of a second delivery member that is arranged in the delivery direction D1 of the medium M with a gap from the delivery roller 21 and is arranged above the delivery roller 21 to deliver the uppermost medium M1. A tension detector 50 for detecting that the uppermost medium M1 is stretched between the roller 22 and the delivery rollers 21 and 22 in the delivery direction D1; and a control unit 61 that controls not to lift the supply tray 10 when it is detected that the medium M1 is stretched. The control unit 61 allows the top medium M1 to be stretched by the tension detection unit 50 while the top medium M1 is fed under a predetermined condition (for example, a specified number of sheets or more) by the feed rollers 21 and 22. If it is continuously detected that the supply tray 10 is being lifted, control is performed to raise the supply tray 10 . For example, the control unit 61 performs control to raise the supply tray 10 when the uppermost medium M1 is no longer detected after the suspension detecting unit 50 detects that the uppermost medium M1 has been suspended. conduct.

By the way, when a plurality of mediums M are erroneously entered between, for example, the feeding roller 22 and the separation plate 23 in the feeding direction D1, the tension detection unit 50 continues until the plurality of media M are fed out. It continues to detect that the uppermost medium M1 is stretched, and the supply tray 10 does not rise. In this regard, the control unit 61 can raise the supply tray 10 in anticipation before all the media M that have erroneously entered in the feeding direction D1 are fed. Therefore, it is possible to avoid the occurrence of empty feeding due to the supply tray 10 not being lifted in time for the delivery operation of the delivery rollers 21 and 22 . In addition, compared to the mode in which it is detected that the uppermost medium M1 is at the supply height on the upstream side of the feeding roller 21 in the feeding direction D1 among the media M stacked on the supply tray 10, It is possible to accurately detect that the uppermost medium M1 can be supplied between the delivery roller 21 and the delivery roller 22 that deliver the medium M1. Further, the tension detection unit 50 is for detecting that the number of media M stacked on the supply tray 10 decreases as the uppermost medium M1 is delivered by the delivery rollers 21 and 22. , the control unit 61 can prevent the air feeding of the medium M as described above even when no new configuration is added. Therefore, according to the first embodiment, it is possible to prevent the medium M from being air-fed with a simple configuration.

<Second embodiment>
9 and 10 are front views showing the internal structure of the medium feeding device 2 according to the second embodiment.

In the second embodiment, the medium feeding device 2 further includes a medium height detector 90 in addition to the configuration of the medium feeding device 1 according to the first embodiment. Therefore, the medium height detection unit 90 will be described in detail, and description of other matters will be omitted.

As shown in FIGS. 9 and 10 , the medium height detection section 90 has a pushed-up portion 91 and a medium height detection sensor 92 . The medium height detection unit 90 detects that the top medium M1 is at the supply height when the feed roller 21 feeds out the top medium M1.

The push-up part 91 has a connecting plate 91a and a detected piece 91b.
The connecting plate 91 a couples the delivery rollers 21 and 22 by rotatably supporting the rotation shaft of the delivery roller 21 and the delivery roller 22 . The connecting plate 24 is rotatably arranged so that the delivery roller 21 moves up and down about the rotation axis of the delivery roller 22 .

The connection plate 91a (push-up portion 91) is configured so that the delivery roller 21 (an example of the upstream side in the delivery direction D1 of the portion where the push-up portion 51 is pushed up by the top medium M1) is pushed up by the top medium M1. , rotates clockwise in FIGS. 9 and 10 together with the delivery roller 21. On the other hand, when the delivery roller 21 is not pushed up by the uppermost medium M1, the connecting plate 91a (push-up portion 91) rotates counterclockwise in FIGS. rotate to

The piece 91b to be detected is provided above, for example, the delivery roller 21 on the connecting plate 91a.

The medium height detection sensor 92 has a U-shape (U-shape) opening downward to the right. The detection light of the medium height detection sensor 92 is blocked by the detected piece 91b of the pushed-up part 91 pushed up by the uppermost medium M1 as described above, so that the uppermost medium M1 reaches the supply height. It outputs an ON signal indicating that it is on. In addition, the medium height detection sensor 92 detects that the uppermost medium M1 does not reach the supply height when the detection light is not blocked by the detected piece 91b of the pushed-up portion 91, which is not pushed up by the uppermost medium M1 as described above. output an OFF signal indicating that it is not in Thus, the medium height detection unit 90 can detect that the uppermost medium M1 is at the supply height.

In the second embodiment, the control unit 61 shown in FIG. 4 causes the tension detection unit 50 to detect the topmost medium M1 while the feeding unit 20 feeds out the topmost medium M1 for a predetermined number or more (an example of a predetermined condition). , the supply tray 10 is raised based on the detection result of the medium height detection unit 90 instead of raising the supply tray 10 on the assumption that the medium M1 is continuously stretched. control.

For example, the control unit 61 continuously detects that the uppermost medium M1 is being stretched by the tension detection unit 50 while the uppermost medium M1 is being fed out by the feeding unit 20 in a predetermined number or more. In this case, the output result of the medium height detection sensor 92 while the specified number of sheets are being fed may be referred to perform control to raise the supply tray 10 .

After that, the control section 61 may perform control to raise the supply tray 10 again based on the output result of the tension detection section 50 . Alternatively, the control unit 61 performs control to raise the supply tray 10 based on the output result of the medium height detection unit 90 until the feeding operation of the medium M (for example, a print job) is completed. After the feeding operation is completed, the control for raising the supply tray 10 may be performed based on the output result of the tension detector 50 again.

In the second embodiment described above, it is possible to obtain the effect obtained in the above-described first embodiment, for example, the effect that it is possible to prevent the medium M from being air-fed with a simple configuration.

In addition, in the second embodiment, the medium feeding device 2 includes the medium height detection unit 90 that detects that the uppermost medium M1 is at the supply height when the feeding roller 21 feeds out the uppermost medium M1. Prepare more. The control unit 61 continuously detects that the uppermost medium M1 is stretched by the tension detecting unit 50 while the uppermost medium M1 is fed out by the feeding rollers 21 and 22 in a predetermined number or more. If so, control is performed to raise the supply tray 10 based on the detection result of the medium height detection unit 90 .

Thus, the medium height detection unit 90 detects that the uppermost medium M1 is at the supply height. Therefore, the medium height detection unit 90 detects that the uppermost medium M1 is not at the supply height before all the media M mistakenly entering between the delivery roller 22 and the separating plate 23 are delivered. can be detected. Therefore, when the suspension detection unit 50 continuously detects that the uppermost medium M1 is suspended due to the influence of a plurality of media M that have erroneously entered, the medium height detection Portion 90 can be used to more accurately detect whether the top medium M1 is at the feed height. Therefore, the control unit 61 can appropriately raise the supply tray 10, so that the blank feeding of the medium M can be prevented.

It should be noted that the present invention is not limited to the above-described first or second embodiment as it is, and can be embodied by modifying the constituent elements without departing from the gist of the present invention at the implementation stage. Moreover, various inventions can be formed by appropriate combinations of the plurality of constituent elements disclosed in the above-described first and second embodiments. For example, all the components shown in the first embodiment and the second embodiment 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 liftable supply tray on which media are loaded;
a first feeding member for feeding the uppermost medium stacked on the supply tray;
a second feeding member arranged at a distance from the first feeding member in the medium feeding direction and above the first feeding member for feeding the uppermost medium;
a stretch detection unit that detects that the uppermost medium is stretched between the first feeding member and the second feeding member in the feeding direction;
a control unit that controls not to raise the supply tray when it is detected that the uppermost medium is stretched by the stretch detection unit;
The control unit is arranged such that the top medium is stretched by the tension detection unit while the top medium is fed under a predetermined condition by the first feeding member and the second feeding member. A medium feeding device characterized by performing control to raise the feeding tray when the above is continuously detected.

[Appendix 2]
The control unit performs control to raise the supply tray when the top medium is no longer detected after the stretch detection unit detects that the top medium is stretched. The medium supply device according to appendix 1, characterized by:

[Appendix 3]
further comprising a medium height detection unit that detects that the top medium is at the supply height when the first feeding member feeds the top medium,
When the tension detection unit continuously detects that the top medium is stretched while the top medium is paid out for a specified number or more, the control unit controls the above-mentioned 3. The medium supply device according to appendix 1 or 2, wherein control is performed to raise the supply tray based on a detection result of a medium height detection unit.

Reference Signs List 1, 2 medium supply device 10 supply tray 20 delivery unit 21, 22 delivery roller 23 separation plate 24 guide plate 30 housing 31 upper door 40 drawer 41 regulation plate 42, 43 side fence 44 end fence 50 tension detection unit 51 cover push-up portion 51a arm 51b rotating shaft member 51c roller 51d piece to be detected 52 tension detection sensor 61 control portion 62 storage portion 63 interface portion 70 elevation drive portion 80 medium passage detection sensor 90 medium height detection portion 91 pushed-up portion 91a connecting plate 91b piece to be detected 92 medium height detection sensor 100 image forming apparatus D1 drawing direction D2 drawing direction M medium M1 top medium

Claims (2)

a liftable supply tray on which media are loaded;
a first feeding member for feeding the uppermost medium stacked on the supply tray;
a second feeding member arranged at a distance from the first feeding member in the medium feeding direction and above the first feeding member for feeding the uppermost medium;
a stretch detection unit that detects that the uppermost medium is stretched between the first feeding member and the second feeding member in the feeding direction;
a control unit that controls to raise the supply tray based on the suspension detection unit not detecting that the uppermost medium is suspended,
The control unit detects the tension while the uppermost medium is fed out by the first feeding member and the second feeding member at least a specified number, which is larger than the number of the media to be fed out. A medium feeding device, wherein control is performed to raise the feeding tray also based on continuous detection that the uppermost medium is stretched by a unit. further comprising a medium height detection unit that detects that the top medium is at the supply height when the first feeding member feeds the top medium,
The control unit continuously detects that the top medium is stretched by the stretch detection unit while the top medium is paid out for the specified number or more, 2. The medium feeding device according to claim 1, wherein control is performed to raise the feeding tray also based on the detection result of the medium height detection section.

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