Media supply device

Abstract

To provide a medium supply device reduced in double feeding and idle feeding.SOLUTION: A medium supply device has a supply part (a paper feeding roller 12, a handling plate 13, etc) for supplying a medium (sheet P), a medium detection sensor (a registration sensor S) for detecting the medium supplied by the supply part, and a control part 18a for changing supply settings of the supply part on the basis of a detection result of the medium detection sensor. The control part 18a switches the supply setting to be changed among the multiple supply settings of the supply part, on the basis of the detection results of the medium detection sensor.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a medium supplying device that supplies a medium. [Background technology]

[0002] Conventionally, a paper feeding device has been known in which the leading edge of the fed paper is brought into contact with a pair of registration rollers, causing it to stop temporarily, thereby creating slack, and then the paper is transported toward the printing unit at a predetermined timing, in order to eliminate paper tilt caused by skewing the paper during transport, or to synchronize the printing start position on the printing paper with the printing start position by the printing unit.

[0003] In such a paper feeding device, a paper feeding device has been proposed that determines whether one sheet or multiple sheets of paper are being transported based on the load current of the paper feeding pickup roller, and if multiple sheets are being transported, drives the paper feeding pickup roller at a slower speed than when transporting a single sheet (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-076155 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, in a printing device, double feeding or empty feeding may occur during paper feeding.

[0006] When double feeding occurs, blank pages may be included in the output paper, changing the page order; thicker paper may come into contact with the printing section such as the inkjet head, damaging the printing section or soiling the transported paper; or printing operations may be stopped, requiring work to clear jams and errors, reducing paper feeding efficiency (productivity).

[0007] On the other hand, when empty feeding occurs, paper feeding slows down, so the paper does not slacken sufficiently due to contact with the registration roller pair, or it takes time to feed each sheet, resulting in reduced paper feeding efficiency (productivity).

[0008] For example, as in the paper feeding device described above, double feeding can sometimes be suppressed by slowing down the conveying speed of the paper feed pickup roller (paper feed unit). Also, empty feeding can sometimes be suppressed by increasing the conveying speed. However, because the ease with which double feeding and empty feeding can be resolved by changing the paper feed settings varies depending on the degree of deterioration of each component of the paper feed unit and the stacking position of the paper in the tray, simply changing a specific paper feed setting (conveying speed) each time will not reliably resolve the issue.

[0009] The present invention provides a medium feeding device that can reduce the occurrence of double feeding and empty feeding. [Means for solving the problem]

[0010] In one aspect, a media supply device includes a supply unit that supplies media, a media detection sensor that detects the media supplied by the supply unit, and a control unit that changes the supply setting of the supply unit based on the detection result of the media detection sensor, and the control unit switches the supply setting to be changed from among the multiple supply settings of the supply unit based on the detection result of the media detection sensor. [Effects of the Invention]

[0011] According to the above aspect, it is possible to reduce the occurrence of double feeding and empty feeding. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram illustrating an internal structure of a printing device according to an embodiment. [Figure 2] FIG. 2 illustrates a control configuration of a printing apparatus according to an embodiment. [Figure 3] FIG. 2 is a diagram illustrating a configuration of an external paper feed unit according to an embodiment. [Figure 4] FIG. 3 is a diagram illustrating a control configuration of an external paper feed unit according to an embodiment. [Figure 5] 10A and 10B are diagrams for explaining sheets on which no empty feeding or double feeding has occurred after a reference detection time has elapsed in an embodiment. [Figure 6] 10A and 10B are diagrams for explaining a paper sheet that tends to be empty-fed after a reference detection time has elapsed in an embodiment. [Figure 7] 10A and 10B are diagrams for explaining sheets that appear to be double-fed after a reference detection time has elapsed according to an embodiment. [Figure 8] FIG. 10 is a diagram for explaining an example of a condition in which double feeding and empty feeding occur in one embodiment. [Figure 9] 10A and 10B are diagrams illustrating an example of the priority order for switching paper feed settings and the contents of changes to paper feed settings when double feeding or empty feeding occurs in an embodiment. [Figure 10] FIG. 10 is a diagram (part 1) for explaining detection times corresponding to accelerations in one embodiment. [Figure 11] FIG. 10 is a diagram (part 2) for explaining detection times corresponding to accelerations in one embodiment. [Figure 12] 10A and 10B are diagrams for explaining adjustment of the separating angle of the separating plate in one embodiment. [Figure 13] 10A and 10B are diagrams for explaining adjustment of the separating pressure of the separating plate in one embodiment. [Figure 14] 10A and 10B are diagrams for explaining an example of detection of empty feed / double feed in one embodiment. [Figure 15] 10A and 10B are diagrams for explaining another example of detection of empty feed / double feed in an embodiment. [Figure 16] FIG. 10 is a diagram (part 1) for explaining a change in paper feed settings according to an embodiment. [Figure 17] FIG. 10 is a diagram (part 2) for explaining a change in paper feed settings according to an embodiment. [Figure 18] FIG. 10 is a diagram (part 1) for explaining changes to a plurality of paper feed settings in one embodiment. [Figure 19]FIG. 10 is a diagram (part 2) for explaining changes to a plurality of paper feed settings according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A medium supplying device according to an embodiment of the present invention will be described below with reference to the drawings.

[0014] FIG. 1 is a diagram showing the internal structure of a printing device 1 according to an embodiment.

[0015] FIG. 2 is a diagram showing the control configuration of the printing device 1.

[0016] 1 and 2, the printing device 1 includes an external paper feed unit 10, an internal paper feed unit 20, a printing unit 40, a printing transport unit 50, a paper discharge unit 60, and a registration sensor S. Also, as shown in FIG. 1, the printing device 1 includes a pair of registration rollers 31, an acceleration transport unit 32, a constant speed transport unit 33, a reverse transport unit 34, a paper re-feed unit 35, a paper discharge transport unit 36, a straight transport unit 37, and path switching units 38 and 39. Also, as shown in FIG. 2, the printing device 1 includes a transport drive unit 70, a control unit 81, a memory unit 82, and an interface unit 83.

[0017] It should be noted that the paper P in this embodiment is an example of a medium, and this medium may be a sheet-like object made of a material other than paper, or an object with a folded portion such as an envelope. Therefore, in this specification, paper feeding is an example of supplying, and paper ejection is an example of discharging. Therefore, paper feeding can be substituted for supplying (for example, a paper re-feeding unit can be substituted for a re-feeding unit), paper ejection can be substituted for discharging, and paper can be substituted for medium.

[0018] In Figure 1, the straight transport path R1 for paper P continuing from the external paper feed unit 10 or the internal paper feed unit 20 is shown by a solid line, the path continuing from the circulatory transport path R2 for double-sided printing located above the printing unit 40 to the discharge transport path R3 is shown by a dotted line, and the reverse transport path R2a of the circulatory transport path R2 is shown by a dashed line.

[0019] As shown in FIGS. 1 and 3, the external paper feed unit 10 includes a paper feed tray 11, a paper feed roller 12, and a separation plate 13. Also, as shown in FIG. 4, the external paper feed unit 10 includes a thickness setting unit 14 (see FIG. 1), a feed drive unit 15, an elevation drive unit 16, a separation plate drive unit 17, a control unit 18a, a memory unit 18b, and an interface unit 18c. The external paper feed unit 10 is disposed, for example, so as to be exposed to the outside of the printing device 1. Note that each unit of the external paper feed unit 10, excluding the control unit 18a, the memory unit 18b, and the interface unit 18c, functions as an example of a supply unit that supplies media. The medium supply device in this embodiment includes this supply unit, a registration sensor S, and a control unit 18a (or a control unit 81, described later).

[0020] 3, unprinted sheets of paper P are stacked on the paper feed tray 11. The paper feed tray 11 is an example of a tray on which media are stacked.

[0021] The paper feed roller 12 has a scraper roller 12a and a pickup roller 12b, and feeds and transports the uppermost paper P among the multiple sheets of paper P stacked in the paper feed tray 11. The paper feed roller 12 is an example of a supply member that feeds a medium.

[0022] The separation plate 13 sandwiches the paper P between itself and the pickup roller 12b to separate the paper P one by one. The separation plate 13 is an example of a separating member that sandwiches the medium between itself and the supply member (paper feed roller 12) to separate the medium.

[0023] 1 and 4, the thickness of the paper P loaded in the paper feed tray 11 is set by the user in the thickness setting unit 14. For example, the thickness setting unit 14 has a lever or dial that can be moved to a position marked "cardboard" indicating that the paper P is cardboard, a position marked "plain paper" indicating that the paper P is plain paper, and a position marked "thin paper" indicating that the paper P is thin paper. The control unit 18a, which will be described later, acquires information about the thickness of the paper P set in the thickness setting unit 14. Note that the control unit 18a may also acquire information about the thickness of the paper P that is set in a print job, from the operation panel of the printing device 1, or the like.

[0024] 4 is an actuator such as a motor that drives the paper feed roller 12. In the present embodiment, adjustment of the acceleration and conveyance speed of the external paper feed unit 10 will be described, but these are the acceleration and conveyance speed of the supply drive unit 15, and the acceleration and conveyance speed of the paper P that is actually conveyed will be smaller or slower than the values ​​of the actuator due to slippage between the paper P and the paper feed roller 12, etc.

[0025] The lifting / lowering drive unit 16 is an actuator such as a motor that moves the paper feed tray 11 up and down.

[0026] The separation plate drive unit 17 is an actuator such as a motor that moves the separation plate 13 in a direction away from the pickup roller 12b (paper P) (see separation plate 13(1)) and a direction approaching the pickup roller 12b (see separation plate 13(2)) as shown in Fig. 12, which will be described later. Also, the separation plate drive unit 17 rotates the separation plate 13 in a direction rising toward the pickup roller 12b (see separation plate 13(+)) and a direction leaning away from the pickup roller 12b (see separation plate 13(-)) as shown in Fig. 13, which will be described later.

[0027] The control unit 18a has a processor (e.g., a CPU (Central Processing Unit)) that functions as an arithmetic processing device that controls the overall operation of the external paper feed unit 10. As will be described in detail later, the control unit 18a changes the paper feed setting (an example of a supply setting) of the external paper feed unit 10 based on the detection result of the registration sensor S, or switches the paper feed setting to be changed from among multiple paper feed settings of the external paper feed unit 10. Note that if the external paper feed unit 10 and a medium supply device including the registration sensor S are integrally disposed in the printing device 1 (supply destination device) as shown in FIG. 1, the control unit 81 that controls the overall operation of the printing device 1 may function as the control unit 18a.

[0028] The storage unit 18b has, for example, memory such as a ROM (Read Only Memory), which is a read-only semiconductor memory in which a predetermined control program is pre-recorded, and a RAM (Random Access Memory), which is a semiconductor memory that can be written and read at any time and is used as a working memory area as needed when the processor executes various control programs.

[0029] The interface unit 18c exchanges various types of information with external devices. For example, the interface unit 18c exchanges various types of information with the interface unit 83 of the printing device 1 and the like.

[0030] As shown in FIG. 1, the internal paper feed unit 20 has a first paper feed unit 21, a second paper feed unit 22, and a third paper feed unit .

[0031] The first paper feed unit 21, the second paper feed unit 22, and the third paper feed unit 23 are arranged inside the printing device 1, lined up in this order from top to bottom. The first paper feed unit 21, the second paper feed unit 22, and the third paper feed unit 23 each have a paper feed tray 21a, 22a, 23a on which unprinted paper P is stacked, and paper feed rollers 21b, 22b, 23b which are an example of a supply member that feeds and transports the uppermost paper P among the multiple sheets of paper P stacked in the paper feed trays 21a, 22a, 23a. Although not shown, the internal paper feed unit 20 also includes actuators such as motors that drive the paper feed rollers 21b, 22b, 23b.

[0032] The registration roller pair 31 is disposed on the upstream side of the printing unit 40 and the print transport unit 50 in the transport direction of the straight transport path R1 continuing from the external paper feed unit 10 or the internal paper feed unit 20. The registration roller pair 31 is abutted against the paper sheet P transported from the external paper feed unit 10, the internal paper feed unit 20, or the paper re-feed unit 35 toward the printing unit 40. This allows the registration roller pair 31 to correct skew of the paper sheet P and transport the paper sheet P while nipping it. Note that, when the external paper feed unit 10 is considered to be a primary supply unit, the registration roller pair 31 functions as a secondary supply unit that supplies the paper sheet P supplied by this primary supply unit.

[0033] The acceleration conveyance section 32 is capable of accelerating and conveying the paper sheet P on the circulating conveyance path R2. The acceleration conveyance section 32 has acceleration roller pairs 32a, 32b, and 32c that nip and convey the paper sheet P.

[0034] The constant speed conveying section 33 conveys the paper P at a constant speed at a variable conveying speed on the downstream side of the accelerating conveying section 32 in the conveying direction of the circulating conveying path R2. The constant speed conveying section 33 has constant speed roller pairs 33a, 33b, and 33c that nip and convey the paper P.

[0035] The reverse conveying section 34 is a pair of switchback rollers that nip and switchback convey the paper P in a reverse conveying path R2a located downstream in the conveying direction from the constant speed conveying section 33 of the circulating conveying path R2, thereby reversing the front and back of the paper P.

[0036] The paper re-feeding unit 35 is a pair of paper re-feeding rollers located downstream of the constant speed transport unit 33 on the circulating transport path R2 in the transport direction, and re-feeds the paper P toward the printing unit 40. The paper re-feeding unit 35 decelerates and transports the paper P when the paper P abuts against the pair of registration rollers 31.

[0037] The discharge conveyance section 36 is a pair of discharge rollers that nip and convey the paper P toward the discharge section 60 on a discharge conveyance path R3 connected to the circulation conveyance path R2 upstream of the reverse conveyance path R2a in the conveyance direction.

[0038] The straight conveying section 37 is a pair of straight rollers that are arranged at the downstream end of the straight conveying path R1 in the conveying direction and nip and convey the paper P toward a paper discharge section, conveying section, or post-processing device, etc., not shown, that is connected to the printing device 1.

[0039] The path switching unit 38 switches the transport path of the paper P on the straight transport path R1 on which printing has been performed by the printing unit 40 between the straight transport path R1 and the circulating transport path R2. The path switching unit 38 is, for example, a flipper.

[0040] The path switching unit 39 switches the path of the paper P transported on the circulating transport path R2 between the reverse transport path R2a and the discharge transport path R3. The path switching unit 39 is, for example, a flipper.

[0041] The printing unit 40 has, for example, a line-head type inkjet head (not shown) for each color used for printing. The printing method of the printing unit 40 may be a printing method other than the inkjet printing method.

[0042] The print transport unit 50 is disposed opposite the print unit 40 and transports the paper P in the print unit 40. The print transport unit 50 has a plurality of pulleys 51, a belt 52 stretched across these pulleys 51, a suction fan 53 that sucks air through a plurality of holes provided in the belt 52 to cause the paper P to adhere to the belt 52, a guide roller 54 disposed opposite the pulley 51 at the upstream end of the print transport unit 50 in the transport direction, and a guide roller 55 disposed opposite the pulley 51 at the downstream end of the print transport unit 50 in the transport direction. Note that the print transport unit 50 is not limited to one that transports the paper P while adsorbing it.

[0043] The paper discharge unit 60 is disposed so as to be exposed to the outside of the printing device 1. The paper discharge unit 60 has a paper discharge tray 61 on which printed paper P is stacked, and a pair of paper discharge rollers 62 that transports the paper P toward the paper discharge tray 61.

[0044] The registration sensor S is disposed on the straight conveying path R1 downstream of the external paper feed unit 10 in the conveying direction of the paper P and upstream of the pair of registration rollers 31. The registration sensor S detects the paper P supplied by the external paper feed unit 10 and the paper re-feed unit 35. The registration sensor S is an example of a medium detection sensor that detects the paper P supplied by the external paper feed unit 10.

[0045] 2 includes a registration drive unit 71 that drives the registration roller pair 31, an acceleration drive unit 72 that drives the acceleration conveyance unit 32, a constant speed drive unit 73 that drives the constant speed conveyance unit 33, a reversal drive unit 74 that drives the reversal conveyance unit 34, a paper re-feed drive unit 75 that drives the paper re-feed unit 35, a paper discharge drive unit 76 that drives the paper discharge conveyance unit 36, a linear drive unit 77 that drives the linear conveyance unit 37, and switching drive units 78 and 79 that drive the path switching units 38 and 39. Each drive unit includes one or more actuators such as motors. Note that a single actuator may serve as multiple drive units.

[0046] The control unit 81 has a processor (e.g., a CPU) that functions as an arithmetic processing unit that controls the overall operation of the printing device 1. The control unit 81 may change the supply setting of the external paper feed unit 10 or switch the supply setting to be changed from among multiple supply settings of the external paper feed unit 10 based on the detection result of the registration sensor S, instead of the control unit 18a of the external paper feed unit 10 shown in FIG.

[0047] The storage unit 82 includes, for example, a memory such as a ROM, which is a read-only semiconductor memory in which predetermined control programs are pre-recorded, a RAM, which is a semiconductor memory that can be written and read at any time and is used as a working memory area as needed when the processor executes various control programs, a hard disk drive, etc.

[0048] The interface unit 83 exchanges various information with external devices. For example, the interface unit 83 receives a print job including print data from a user terminal, and exchanges various information with the interface unit 18c of the external paper feed unit 10.

[0049] Next, empty feeding and multiple feeding of the paper sheets P will be described with reference to FIGS.

[0050] First, if the detection time from when the external paper feed unit 10 starts feeding the paper P (for example, when the control unit 18a sends an activation signal to the supply drive unit 15) to when the paper P is detected by the register sensor S is the same as the reference detection time, which is a predetermined theoretical value, then the leading edge of the paper P will be detected by the register sensor S as shown in Figure 5 after the reference detection time has elapsed since the external paper feed unit 10 started feeding the paper P.

[0051] Next, if the paper P is being fed empty and the feeding of the paper P is delayed, after the reference detection time has elapsed since the external paper feed unit 10 started feeding the paper P, as shown in FIG. 6, the leading edge of the paper P does not reach the registration sensor S and is not detected by the registration sensor S. In other words, the detection time becomes longer than the reference detection time.

[0052] Next, when the sheets P are fed quickly with a tendency for multiple feeding, such as when the following sheet P(2) is transported along with the feeding of the preceding sheet P(1) as shown in Fig. 7, the leading edge of the sheet P passes through the registration sensor S after the reference detection time has elapsed since the external sheet feed unit 10 started feeding the sheet P, as shown in Fig. 7. In other words, the detection time is shorter than the reference detection time.

[0053] The empty feed shown in Fig. 6 and the double feed shown in Fig. 7 can be said to occur, for example, under the conditions shown in Fig. 8. Note that the terms "slightly empty feed" and "slightly double feed" refer to a state in which empty feed or double feed occurs to the extent that no empty feed error or double feed error occurs.

[0054] For example, if the separation plate 13 or the pickup roller 12b (feed roller 12) is worn, the separation performance of the paper P by the separation plate 13 deteriorates, making it easy for double feeding of the paper P to occur. Furthermore, if paper dust accumulates on the feed roller 12, empty feeding of the paper P is likely to occur due to slippage between the paper P and the feed roller 12, and if paper dust accumulates on the separation plate 13, the separation performance of the paper P by the separation plate 13 deteriorates, making it easy for double feeding of the paper P to occur. Furthermore, if the stacking position of the paper P in the paper feed tray 11 is near the rear end (upstream in the conveying direction), paper feeding is delayed and empty feeding is likely to occur, and if the stacking position is near the front end (downstream in the conveying direction), double feeding is likely to occur. Furthermore, if the side fences (not shown) that regulate the widthwise position of the paper P on the paper feed tray 11 in the transport direction are installed narrower than specified, empty feeding is likely to occur due to friction between the paper P and the side fence, and if the side fences are installed wider than specified, friction between the paper P and the side fences is not generated and double feeding is likely to occur. Furthermore, empty feeding is likely to occur if the paper quality of the paper P is such that friction is unlikely to occur, and double feeding is likely to occur if the paper quality of the paper P is such that friction is likely to occur.

[0055] When the control unit 18a detects empty feed (slightly empty feed) or double feed (slightly double feed), the control unit 18a changes the paper feed setting, for example, as shown in Fig. 9, in order to eliminate the empty feed or double feed. As will be described later, the changed paper feed setting is switched, for example, in the order of priority (1) to (8), based on the detection result of the registration sensor S.

[0056] For example, when the separating pressure of the separating plate 13 is changed, if empty feeding is detected, the control unit 18a controls the separating plate drive unit 17 to move the separating plate 13 in a direction (see separating plate 13(1)) away from the pickup roller 12b (paper P) to lower the separating pressure, as shown in Fig. 12. Also, if double feeding is detected, the control unit 18a controls the separating plate drive unit 17 to move the separating plate 13 in a direction (see separating plate 13(2)) approaching the pickup roller 12b (paper P) to increase the separating pressure.

[0057] Furthermore, when the separation angle of the separation plate 13 is changed, if empty feeding is detected, the control unit 18a controls the separation plate drive unit 17 to rotate the separation plate 13 in the negative direction (see separation plate 13(-)) so that it falls away from the pickup roller 12b (paper P) side, as shown in Fig. 13. Furthermore, if double feeding is detected, the control unit 18a controls the separation plate drive unit 17 to rotate the separation plate 13 in the positive direction (see separation plate 13(+)) so that it rises toward the pickup roller 12b (paper P) side.

[0058] The paper feed settings, ie, the separating pressure and the separating angle of the separating plate 13, are an example of the position setting of the external paper feed unit 10.

[0059] Incidentally, regarding the sheet feeding acceleration at the start of sheet feeding from the external sheet feeding unit 10, the acceleration A [m / s 2 In the case of [0.01], the detection time [ms] from the start of feeding in the external paper feed unit 10 to the detection by the registration sensor S is shorter than the stable range for about the 10th to 55th sheets of paper P being conveyed, which means that the sheets P are likely to be fed multiple times. On the other hand, the acceleration A [m / s 2 ] to acceleration B [m / s 2], the detection time becomes longer and falls within the stable range for approximately the 7th to 95th sheets of paper P being conveyed. In this way, it can be said that increasing the acceleration shortens the detection time, and decreasing the acceleration lengthens the detection time.

[0060] Therefore, when the paper feed acceleration is changed, the control unit 18a controls the supply drive unit 15 to increase the paper feed acceleration when empty feed (slightly empty feed) is detected, and to decrease the acceleration when double feed (slightly double feed) is detected, as shown in Figure 9.

[0061] Similarly, with regard to the deceleration of the external paper feed unit 10 when the paper P hits the pair of registration rollers 31, the control unit 18a controls the supply drive unit 15 so that if empty feed is detected, the deceleration acceleration is increased (acceleration), and if double feed is detected, the deceleration is decreased.

[0062] In addition, when the paper feed start timing is changed, the control unit 18a controls the supply drive unit 15 so as to advance the paper feed start timing when empty feeding is detected, and to delay the paper feed start timing when double feeding is detected.

[0063] Furthermore, when the amount of slack is changed, the control unit 18a controls the supply drive unit 15 so that, if empty feed is detected, the amount of slack formed by the paper P hitting the registration roller pair 31 is increased (i.e., the transport amount, which is the drive amount of the paper feed roller 12 for transporting one sheet of paper P, is increased), and, if double feed is detected, the amount of slack is decreased (the transport amount is reduced).

[0064] Furthermore, when the paper feed speed is changed, the control unit 18a controls the supply drive unit 15 so as to increase the paper feed speed when empty feed is detected, and to decrease the paper feed speed when double feed is detected.

[0065] Furthermore, when the upper limit paper position is changed, control unit 18a controls lifting / lowering drive unit 16 so that paper feed tray 11 (the uppermost paper P stacked in paper feed tray 11) is raised if empty feeding is detected, and lowers paper feed tray 11 if double feeding is detected. As an example, control unit 18a controls lifting / lowering drive unit 16 to stop raising paper feed tray 11 when an upper limit detection sensor (not shown) detects the position of scraper roller 12a, which is pressed by paper P on paper feed tray 11 and moves upward. However, when raising paper feed tray 11, the amount by which paper feed tray 11 is raised can be increased after the upper limit detection sensor detects it, and when lowering paper feed tray 11, the amount by which paper feed tray 11 is raised can be decreased after the upper limit detection sensor detects it.

[0066] The height of the paper feed tray 11 and the scraper roller 12a (paper feed roller 12), which are paper feed settings, are an example of the position setting of the external paper feed unit 10, similar to the above-mentioned separating pressure and separating angle of the separating plate 13. Regarding this position setting, the control unit 18a may notify the user of the changed position setting by displaying on a display unit (not shown) or outputting sound from a sound output unit (not shown), so that the position setting may be considered as having been changed.

[0067] The paper feed setting priorities (1) to (8) shown in Fig. 9 may be set separately for cases where empty feeding occurs and cases where double feeding occurs. Alternatively, the paper feed setting priorities (1) to (8) shown in Fig. 9 may be set for each paper type (one example of a medium type) such as the thickness, size, or material of the paper P. For example, the control unit 18a may record the paper type and the usage status of the external paper feed unit 10 (printing device 1) (number of prints, number of times each component is used, etc.) when changing the paper feed settings, and may reset the paper feed setting priorities to their initial values ​​when the paper type or components are changed. Furthermore, the degree of change of each paper feed setting may be increased or decreased depending on the paper type.

[0068] Furthermore, for example, if the paper feed acceleration or paper feed deceleration is reduced too much, or the paper feed start timing is delayed too much, or the paper feed speed is reduced too much, the conveyance start time of the registration roller pair 31 may be delayed, or the registration roller pair 31 may start conveying the paper P before it reaches the registration roller pair 31, causing a conveyance error. Therefore, it is preferable that the control unit 18a change the paper feed setting or switch the changed paper feed setting so that the paper feed completion time of the paper P from the external paper feed unit 10 falls within a predetermined completion period.

[0069] Next, examples of detecting the empty feed state and the double feed state will be described with reference to FIGS.

[0070] In the example shown in Figure 14, the reference detection time [ms] is 50 [ms], and the detection times [ms] from the start of paper feeding by the external paper feed unit 10 to detection by the register sensor S are 50, 50, 55, 45, 50, 50, 50, 40, 50, 50 [ms] for the first to tenth sheets of paper P, in that order.

[0071] In this case, the difference time between the detection time and the reference detection time is 5 [ms] for the third sheet of paper P, -5 [ms] for the fourth sheet of paper P, and -10 [ms] for the eighth sheet of paper P, and the difference time for the other 1st, 2nd, 5th, 6th, 7th, 9th, and 10th sheets of paper P is 0 [ms].

[0072] 14, when the difference time reaches the threshold value of ±5 [ms], the control unit 18a determines that the detection result of the registration sensor S does not satisfy the standard and changes the paper feed setting. For example, since the difference time of the third sheet P is 5 [ms], the control unit 18a changes the setting for the paper handling pressure of priority (1) shown in FIG. 9 to the case where empty feeding tends to occur, from the sheet P following the third sheet P (the fourth sheet P).

[0073] After that, the difference time for the fourth sheet P with the changed supply setting becomes -5 [ms] again. Therefore, for example, from the fifth sheet P, the control unit 18a returns the change in the separating pressure to the original standard setting, and changes the setting for the separating angle with priority (2) in the case where there is a tendency for double feeding.

[0074] Furthermore, the difference time for the eighth sheet P after the change in the feeding setting is -10 [ms]. Therefore, for example, from the ninth sheet P onwards, the control unit 18a returns the change in the separating angle to the original standard setting, and changes the setting for the sheet feeding acceleration with priority (3) in the case where multiple feeding is likely to occur.

[0075] Next, the example shown in Figure 15 is an example in which the reference detection time [ms] is 50 [ms], and the detection times [ms] from the start of paper feeding by the external paper feed unit 10 to detection by the register sensor S for the first to tenth sheets of paper P are 50, 52, 56, 57, 58, 52, 56, 52, 50, and 51 [ms].

[0076] In this case, the difference times, which are the differences between the detection times and the reference detection times, are 0, 2, 6, 7, 8, 2, 7, 2, 0, and 1 [ms] for the first to tenth sheets of paper P, in that order.

[0077] 15, when the number of times the differential time reaches the threshold value of ±5 [ms] reaches four times (an example of a specified number of times), the control unit 18a determines that the detection result of the registration sensor S does not satisfy the standard and changes the paper feed setting. For example, since the differential time reaches ±5 [ms] or more for the third, fourth, fifth, and seventh sheets of paper P, the control unit 18a changes the setting for the paper handling pressure of priority (1) shown in FIG. 9 to a case where empty feeding is likely, from the sheet P following the seventh sheet P (the eighth sheet P).

[0078] In the example of Figure 15, the differential time is not a negative value during double feed, but if the differential time during double feed is +5 [ms] or more and the negative value of the differential time during empty feed is 5 [ms] or more in succession, the control unit 18a may change the paper feed setting when the number of times the threshold is reached only during empty feed or only during double feed reaches a specified number of times.

[0079] Alternatively, the control unit 18a may change the paper feed setting based on, for example, the sum or average value of the difference times of the past three sheets of paper P (an example of a specified number of sheets) reaching a threshold value.

[0080] Next, changing the paper feed setting will be described with reference to FIGS.

[0081] In the example shown in FIGS. 16 to 19, when the differential time reaches a first threshold (an example of a first standard) of ±15 ms (shown by a dotted line), the control unit 18a determines that the detection result of the registration sensor S does not satisfy the standard and changes the paper feed setting. Then, when the differential time reaches a second threshold (an example of a second standard) of ±20 ms (shown by a thick dashed line), the control unit 18a determines that a double feed error or a blank feed error has occurred and controls the supply drive unit 15 to stop paper feed. The first threshold is a value used to determine whether blank feed or multiple feed (i.e., a slight blank feed or a slight double feed) has occurred to the extent that a paper feed error (supply error) does not occur, and the second threshold is a value used to determine that the detection result of the registration sensor S is a paper feed error (supply error). When the detection result of the registration sensor S reaches the second threshold, for example, if a multiple feed error has occurred, the user may clear the jam, or if a blank feed error has occurred, the external paper feed unit 10 may retry paper feed. Furthermore, when the differential time reaches the second threshold of ±20 [ms] and paper feeding is stopped, the control unit 18a also changes the paper feeding settings for the subsequent paper P in the same way as when the differential time reaches the first threshold.

[0082] After the paper feed setting is changed, if the differential time reaches the first threshold or the second threshold again while the paper feed setting has been changed, the control unit 18a switches the paper feed setting to be changed. Note that it is preferable to change the paper feed setting to a larger degree when the differential time reaches the second threshold than when the differential time reaches the first threshold (for example, in the case of paper feed acceleration, it is preferable to change the acceleration to a larger or smaller value when the differential time reaches the second threshold than when the differential time reaches the first threshold).

[0083] In the differential time [ms] of the 1st to 50th sheets of paper P shown in Figure 16, the differential time of the 19th sheet of paper P reaches the first threshold of -15 [ms], so the control unit 18a changes the separating pressure of the paper feed setting priority (1) shown in Figure 9 to a stronger value because a tendency for double feeding has been detected.

[0084] After that, with the paper feed setting changed, the differential time for the 26th sheet of paper P again reaches the first threshold of -15 [ms], so the control unit 18a returns the paper feed setting priority (1) shown in Figure 9 to the original setting and switches the paper feed setting to be changed to the paper feed angle priority (2) (in the positive direction because a tendency for double feeding has been detected).

[0085] After the paper feed setting to be changed is switched to the separating angle of priority (2), the differential time of the paper P will not reach the first threshold of ±15 [ms] or the second threshold of ±20 [ms]. Therefore, the control unit 18a may change the priority of the separating angle of the last changed paper feed setting (2) to (1) based on the fact that the differential time of the paper P in the state where the paper feed setting has been changed will not reach the first threshold or the second threshold (an example of a change in the detection result of the registration sensor S in the state where the paper feed setting has been changed). In this case, the priority of the separating pressure of the paper feed setting (1) may be lowered to (2).

[0086] In the differential time [ms] of the 1st to 50th sheets of paper P shown in Figure 17, the differential time of the 20th sheet of paper P reaches the first threshold of -15 [ms], so the control unit 18a changes the separating pressure of the paper feed setting priority (1) shown in Figure 9 to a stronger value because a tendency for double feeding has been detected.

[0087] Thereafter, as in the example shown in Figure 16, with the paper feed setting changed, the differential time for the 26th sheet of paper P again reaches the first threshold value of -15 [ms], so the control unit 18a returns the paper feed setting priority (1) shown in Figure 9 to the original setting and switches the paper feed setting to be changed to the paper feed angle priority (2) (in the positive direction because a tendency for double feeding has been detected).

[0088] Next, since the differential time of the 27th sheet P reaches the second threshold value of -20 ms with the separation angle of priority (2) changed, the control unit 18a determines that a double feed error has occurred, as described above, and controls the supply drive unit 15 to stop paper feeding. Furthermore, the control unit 18a issues a notification urging the user to clear the jam. Once the double feed error is cleared, the control unit 18a returns the separation angle of priority (2) in the paper feed settings shown in FIG. 9 to the original setting, switches the paper feed setting to be changed to the paper feed acceleration of priority (3) (accelerated because double feed has been detected), and resumes printing.

[0089] After this, the differential time reaches the first threshold of -15 [ms] for a while after the paper feed acceleration is changed, but within the specified period after the paper feed setting is changed or switched, if the differential time does not reach the first or second threshold, the paper feed setting to be changed does not need to be switched.

[0090] Thereafter, since the differential time of the 38th sheet of paper P reaches the first threshold value of 15 ms with the paper feed acceleration of priority (3) changed, the control unit 18a returns the paper feed acceleration of priority (3) in the paper feed setting shown in Figure 9 to the original setting, and switches the paper feed setting to be changed to the paper feed deceleration of priority (4) (deceleration because a tendency toward empty feeding has been detected).

[0091] Furthermore, since the differential time for the 39th sheet of paper P reaches the second threshold value of 20 ms with the paper feed deceleration rate of priority (4) changed, the control unit 18a determines that an empty feed error has occurred, as described above, and controls the supply drive unit 15 to stop paper feed and perform a retry. Furthermore, when the empty feed error is resolved due to a successful retry or the like, the control unit 18a returns the paper feed deceleration rate of priority (4) in the paper feed setting shown in Figure 9 to the original setting, switches the paper feed setting to be changed to the paper feed start timing of priority (5) (earlier because empty feed has been detected), and resumes printing.

[0092] After the paper feed setting to be changed is switched to the paper feed start timing with priority (5), the new differential time of the paper P does not reach the first threshold value of ±15 [ms] or the second threshold value of ±20 [ms]. Therefore, the control unit 18a may change the priority of the paper feed start timing of the paper feed setting (5) to (1) based on the fact that the differential time of the paper P in the state where the paper feed setting has been changed does not reach the first threshold value or the second threshold value (an example of a change in the detection result of the registration sensor S in the state where the paper feed setting has been changed). In this case, the priorities of the original paper feed settings (1) to (4) may be lowered to (2) to (5).

[0093] In the differential time [ms] of the 1st to 50th sheets of paper P shown in Figure 18, the differential time of the 19th sheet of paper P reaches the first threshold of -15 [ms], so the control unit 18a changes the separating pressure of the paper feed setting priority (1) shown in Figure 9 to a stronger value because a tendency for double feeding has been detected.

[0094] After that, the differential time for the 26th sheet P reaches the first threshold value of -15 ms again with the paper feed settings changed, so the control unit 18a changes the paper feed setting priority (1) as well as the paper feed angle priority (2) shown in FIG. 9 (in the positive direction because a tendency for double feeding has been detected). Thus, in the example shown in FIG. 18, the control unit 18a simultaneously changes multiple paper feed settings. Note that, while the order of priority when multiple paper feed settings are simultaneously changed is merely an example, it is preferable to change the settings in a specified order, such as (1), (1) and (2), (1) and (3), ..., (1) and the last (8), (2), (2) and (3), (2) and (4), ..., or (1), (1) and (2), (1) and (3), (2) and (3), (2) and (4), (3 and (5), .... Furthermore, a priority order may be set for switching combinations of multiple paper feed settings. Furthermore, three or more paper feed settings may be changed simultaneously.

[0095] After the paper feed setting to be changed is switched to the separating pressure of priority (1) and the separating angle of priority (2), the difference time of the paper P does not reach the first threshold value of ±15 [ms] or the second threshold value of ±20 [ms]. Therefore, the control unit 18a may change the priority of the paper feed setting (2) or the priority of the combination of the paper feed settings (1) and (2) to the highest priority based on the fact that the difference time of the paper P in a state where the paper feed setting has been changed does not reach the first threshold value or the second threshold value (an example of a change in the detection result of the registration sensor S in a state where the paper feed setting has been changed).

[0096] In the differential time [ms] of the 1st to 50th sheets of paper P shown in Figure 19, the differential time of the 20th sheet of paper P reaches the first threshold of -15 [ms], so the control unit 18a changes the separating pressure of the paper feed setting priority (1) shown in Figure 9 to a stronger value because double feeding has been detected.

[0097] After that, with the paper feed settings changed, the differential time for the 26th sheet P again reaches the first threshold value of -15 [ms], so the control unit 18a changes the paper feed setting priority (1) as well as the paper feed setting priority (2) (to the + direction because a tendency for double feeding has been detected) shown in Fig. 9. In this way, even in the example shown in Fig. 19, the control unit 18a changes multiple paper feed settings at the same time.

[0098] Next, since the differential time of the 27th sheet P reaches the second threshold value of -20 ms with the separation angle of priority (1) and the separation angle of priority (2) changed, the control unit 18a determines that a double feed error has occurred, as described above, and controls the supply drive unit 15 to stop paper feeding. The control unit 18a also issues a notification urging the user to clear the jam. Once the double feed error is cleared, the control unit 18a returns the separation angle of priority (2) in the paper feed settings shown in FIG. 9 to the original settings, switches the paper feed settings to the separation pressure of priority (1) and the paper feed acceleration of priority (3) (accelerated because double feed has been detected), and resumes printing.

[0099] After the paper feed setting to be changed is switched to the separating pressure of priority (1) and the paper feed acceleration of priority (3), the differential time of the paper P does not reach the first threshold value of ±15 [ms] or the second threshold value of ±20 [ms]. Therefore, the control unit 18a may change the priority of the paper feed setting (3) or the priority of the combination of the paper feed settings (1) and (3) to the highest priority based on the fact that the differential time of the paper P in a state where the paper feed setting has been changed does not reach the first threshold value or the second threshold value (an example of a change in the detection result of the registration sensor S in a state where the paper feed setting has been changed).

[0100] In the present embodiment described above, the control unit 18a determines that the detection result of the registration sensor S does not satisfy the criteria (multiple feed or empty feed has occurred) based on the fact that the difference between the detection time from when the external paper feed unit 10 feeds the paper until the registration sensor S detects it has reached a threshold value, and changes the paper feed setting or switches the paper feed setting to be changed. However, the control unit 18a may, for example, obtain the time interval at which the registration sensor S detects the paper P, determine that this time interval (detection result) does not satisfy the criteria (for example, the first and second criteria described above) (multiple feed or empty feed has occurred), and change the paper feed setting or switch the paper feed setting to be changed.

[0101] Furthermore, for example, when a transmission sensor that detects the amount of transmission of detection light through paper P is used as a media detection sensor, an example of which is the above-mentioned resist sensor S, the control unit 18a may determine that the criteria (for example, the above-mentioned first and second criteria) are not met (double feeding or empty feeding has occurred) based on the transmission amount that is the detection result of the transmission sensor, and may change the paper feed settings or switch the paper feed settings to be changed.

[0102] In the above-described embodiment, the control unit 18a switches the paper feed setting to be changed in the order of priority (1) to (8) shown in FIG. 9 . However, the timing of changing the paper feed setting or the timing of switching the paper feed setting may be determined by a paper feed setting change model of a learning unit disposed in the external paper feed unit 10, the printing device 1, or the external device. In this case, the control unit 18a acquires information on the timing of changing the paper feed setting and the timing of switching the paper feed setting determined by the paper feed setting change model, and changes the paper feed setting or switches the paper feed setting based on this information. For example, the control unit 18a transmits the paper feed setting and the above-described detection time corresponding to this paper feed setting to the learning unit. The learning unit may perform learning based on the paper feed setting and the above-described detection time corresponding to this paper feed setting, for example, by deep learning, in which the machine itself extracts features, or by receiving features necessary for determining the timing of changing and switching the paper feed setting from a human in advance.

[0103] In the present embodiment described above, the medium supply device includes external paper feeder 10 (all components excluding control unit 18a, memory unit 18b, and interface unit 18c) which is an example of a supply unit, registration sensor S which is an example of a medium detection sensor, and control unit 18a. External paper feeder 10 supplies paper P which is an example of a medium. Registration sensor S detects paper P supplied by external paper feeder 10. Control unit 18a changes the paper feed setting (an example of a supply setting) of external paper feeder 10 based on the detection result of registration sensor S. Furthermore, control unit 18a switches the paper feed setting to be changed from among multiple paper feed settings of external paper feeder 10 based on the detection result of registration sensor S.

[0104] As a result, the control unit 18a can determine that a double feed or an empty feed is occurring, for example, based on the detection result of the registration sensor S, and change the paper feed setting to eliminate this double feed or empty feed. Furthermore, since the control unit 18a switches the paper feed setting to be changed based on the detection result of the registration sensor S, if changing the paper feed setting does not reduce the double feed or empty feed, the degree of freedom in setting changes increases by changing other paper feed settings, making it easier to reduce the double feed or empty feed. Therefore, according to this embodiment, the occurrence of double feeds and empty feeds can be reduced.

[0105] However, if the deceleration of the paper feed acceleration, which is one of the paper feed settings, continues to increase when the double feed cannot be resolved, the start time of the registration roller pair 31 may be delayed, or the registration roller pair 31 may start conveying the paper P before it reaches the registration roller pair 31, causing a conveyance error. In this case, paper feed efficiency decreases. In response to this, the control unit 18a in this embodiment switches the paper feed setting to be changed when the double feed or empty feed cannot be resolved based on the detection result of the registration sensor S. This makes it easier for the paper feed completion time of the paper P from the external paper feed unit 10 to fall within the specified completion period, thereby avoiding a decrease in paper feed efficiency.

[0106] In addition, in this embodiment, if the detection result of the register sensor S does not satisfy the criteria, the control unit 18a changes some of the paper feed settings from among the multiple paper feed settings of the external paper feed unit 10, and then, if the detection result of the register sensor S in the state in which this paper feed setting has been changed does not satisfy the above criteria, the control unit 18a switches the paper feed setting to be changed from among the multiple paper feed settings.

[0107] This allows the paper feed settings to be changed or the paper feed settings to be changed to be switched so that the detection results of the registration sensor S meet the criteria that make it difficult for double feeds and empty feeds to occur, thereby further reducing the occurrence of double feeds and empty feeds.

[0108] In addition, in this embodiment, the control unit 18a switches the paper feed setting to be changed from among multiple paper feed settings when the detection result of the registration sensor S satisfies a first threshold (an example of a first criterion) before reaching a second threshold (an example of a second criterion) for determining a paper feed error (supply error). Incidentally, if a paper feed error occurs based on the detection result of the registration sensor S, and, for example, a retry paper feed of the paper P in an empty feed state or a jam is cleared after the paper feed of the paper P has stopped in a double feed state, paper feed efficiency decreases. On the other hand, if the paper feed setting to be changed is switched when the detection result of the registration sensor S reaches the first threshold before reaching the second threshold for determining a paper feed error, as in this embodiment, the occurrence of a paper feed error can be prevented. Therefore, it is possible to reduce the occurrence of double feeds and empty feeds, and also to prevent a decrease in paper feed efficiency due to the occurrence of a paper feed error.

[0109] Furthermore, in this embodiment, the control unit 18a sets priorities for switching between a plurality of paper feed settings, and changes the priorities based on changes in the detection results of the registration sensor S when the paper feed setting is changed. This allows the occurrence of double feeds and empty feeds to be further reduced by increasing the priority of paper feed settings that are less likely to cause double feeds and empty feeds.

[0110] Furthermore, in this embodiment, the control unit 18a simultaneously changes multiple paper feed settings from among multiple paper feed settings of the external paper feed unit 10. This further increases the degree of freedom in changing settings to reduce double feeds or empty feeds, thereby further reducing the occurrence of double feeds or empty feeds.

[0111] Furthermore, in this embodiment, the detection result of the registration sensor S is the detection time from when the external paper feed unit 10 starts feeding the paper P to when the registration sensor S detects the paper P, and the control unit 18a switches the paper feed setting to be changed from among the multiple paper feed settings of the external paper feed unit 10 based on the fact that the difference between the detection time and the reference detection time has reached a threshold value. This makes it possible to reliably determine whether a double feed or an empty feed has occurred based on the detection time and the reference detection time. Therefore, the paper feed setting to be changed can be accurately switched depending on the occurrence of a double feed or an empty feed. Therefore, the occurrence of a double feed or an empty feed can be further reduced.

[0112] Furthermore, in this embodiment, the medium supply device includes an external paper feed unit 10 (each unit excluding the control unit 18a, the memory unit 18b, and the interface unit 18c) which is an example of a supply unit, a registration sensor S which is an example of a medium detection sensor, and the control unit 18a. The external paper feed unit 10 supplies paper P which is an example of a medium. The registration sensor S detects the paper P supplied by the external paper feed unit 10. The control unit 18a changes the paper feed setting (an example of a supply setting) of the external paper feed unit 10 based on the detection result of the registration sensor S. The paper feed setting includes position setting of at least one of the paper feed tray 11 (an example of a tray) on which the paper P is stacked, the paper feed roller 12 (an example of a supply member) which feeds the paper P stacked on the paper feed tray 11, and the separation plate 13 (an example of a separation member) which sandwiches the paper P between the paper feed roller 12 (pickup roller 12b) and separates the paper P. The control unit 18a changes the position setting of the external paper feed unit 10 based on the detection result of the registration sensor S.

[0113] As a result, the control unit 18a can determine that a double feed or an empty feed is occurring, for example, based on the detection result of the registration sensor S, and change the paper feed setting to eliminate this double feed or empty feed. Furthermore, the control unit 18a changes the position setting of the external paper feed unit 10 based on the detection result of the registration sensor S, so that the distance between the paper P and each component (paper feed roller 12, separation plate 13, etc.) changes, making it easier to reduce double feeds or empty feeds. Therefore, the occurrence of double feeds and empty feeds can be reduced.

[0114] The present invention is not limited to the above-described embodiments, and the components can be modified and embodied without departing from the spirit of the invention. Furthermore, various inventions can be formed by appropriately combining the multiple components disclosed in the above-described embodiments. For example, all of the components shown in the embodiments may be appropriately combined. Naturally, various modifications and applications are possible without departing from the spirit of the invention. The invention as originally claimed in the present application is described below.

[0115] [Appendix 1] a supply unit that supplies a medium; a medium detection sensor that detects the medium supplied by the supply unit; a control unit that changes a supply setting of the supply unit based on a detection result of the medium detection sensor, The control unit switches the supply setting to be changed from the plurality of supply settings of the supply unit based on the detection result of the medium detection sensor. A medium supply device comprising:

[0116] [Appendix 2] The control unit changes some of the supply settings from among the plurality of supply settings of the supply unit when the detection result of the medium detection sensor does not satisfy a standard, and thereafter, when the detection result of the medium detection sensor in a state in which the supply setting has been changed does not satisfy the standard, switches the supply setting to be changed from among the plurality of supply settings. 2. A medium supply device according to claim 1.

[0117] [Appendix 3] The control unit switches the supply setting to be changed from among the plurality of supply settings when the detection result of the medium detection sensor satisfies a first criterion before reaching a second criterion for determining that a supply error has occurred. 3. The medium supply device according to claim 1 or 2.

[0118] [Appendix 4] The control unit sets a priority order for switching the plurality of supply settings, and changes the priority order based on a change in the detection result of the medium detection sensor in a state where the supply setting is changed. 4. A medium supply device according to any one of claims 1 to 3.

[0119] [Appendix 5] The control unit simultaneously changes a plurality of supply settings from among the plurality of supply settings of the supply unit. 5. A medium supply device according to any one of claims 1 to 4.

[0120] [Appendix 6] the detection result is a detection time from when the supply unit starts supplying the medium to when the medium detection sensor detects the medium; The control unit switches the supply setting to be changed from among the plurality of supply settings of the supply unit based on the fact that a difference between the detection time of the medium detection sensor and a reference detection time has reached a threshold value. 6. A medium supply device according to any one of claims 1 to 5.

[0121] [Appendix 7] a supply unit that supplies a medium; a medium detection sensor that detects the medium supplied by the supply unit; a control unit that changes a supply setting of the supply unit based on a detection result of the medium detection sensor, the supply setting includes position setting of at least one of a tray on which the medium is loaded, a supply member that feeds out the medium loaded on the tray, and a separation member that sandwiches the medium between the supply member and the tray to separate the medium, The control unit changes the position setting of the supply unit based on the detection result of the medium detection sensor. A medium supply device characterized by: [Explanation of symbols]

[0122] 1 Printing device 10 External paper feed section 11 Paper tray 12 Paper feed roller 12a Scraper roller 12b Pickup roller 13 Cutting Board 14 Thickness setting section 15 Supply drive unit 16 Lifting drive unit 17 Separating plate drive unit 18a Control section 18b Storage section 18c Interface section 20 Internal paper feed section 21 1st paper feed section 22 2nd paper feed section 23 3rd paper feed section 21a, 22a, 23a Paper tray 21b, 22b, 23b Paper feed roller 31 Registration roller pair 32 Acceleration conveying section 32a, 32b, 32c Acceleration roller pair 33 Constant speed conveying section 33a, 33b, 33c uniform speed roller pair 34 Reversing conveying section (switchback roller pair) 35 Re-feed unit (re-feed roller pair) 36 Paper discharge transport section (paper discharge roller pair) 37 Straight conveying section (straight roller pair) 38,39 Route switching section 40 Printing Department 50 Printing transport section 51 Pulley 52 Belt 53 Suction fan 54,55 Guide roller 60 Paper output section 61 Paper output tray 62 Paper ejection roller pair 70 Conveyor drive unit 71 Resist drive unit 72 Acceleration drive unit 73 Constant velocity drive unit 74 Reversing drive unit 75 Refeed drive unit 76 Paper ejection drive unit 77 Straight drive unit 78,79 Switching drive unit 81 Control Unit 82 Memory section 83 Interface section P Paper R1 Straight conveyor path R2 Circulation Path R2a Reversing transport path R3 paper exit path S register sensor

Claims

1. a supply unit that supplies a medium; a medium detection sensor that detects the medium supplied by the supply unit; a control unit that changes a supply setting of the supply unit based on a detection result of the medium detection sensor, the control unit changes some of the supply settings from among the plurality of supply settings of the supply unit when the detection result of the medium detection sensor does not satisfy a criterion, and thereafter, when the detection result of the medium detection sensor in a state in which the supply setting has been changed does not satisfy the criterion, switches the supply setting to be changed from among the plurality of supply settings; The control unit sets priorities for switching the plurality of supply settings, and changes the priorities based on whether the detection result of the medium detection sensor in a state in which the supply setting has been changed satisfies the criteria. A medium supply device characterized by:

2. The control unit switches the supply setting to be changed from among the plurality of supply settings when the detection result of the medium detection sensor reaches a first threshold before reaching a second threshold for determining that a supply error has occurred.

2. The medium supply device according to claim 1.

3. The control unit simultaneously changes a plurality of supply settings from among the plurality of supply settings of the supply unit.

3. The medium supply device according to claim 1 or 2.

4. the detection result is a detection time from when the supply unit starts supplying the medium to when the medium detection sensor detects the medium; The control unit switches the supply setting to be changed from among the plurality of supply settings of the supply unit based on the fact that a difference between the detection time of the medium detection sensor and a reference detection time has reached a threshold value.

4. The medium supply device according to claim 1, wherein the medium supply device is a medium supplying device.

5. The supply setting includes position setting of at least one of a tray on which the medium is loaded, a supply member that feeds the medium loaded on the tray, and a separation member that sandwiches the medium between the supply member and the tray to separate the medium.

5. The medium supply device according to claim 1, wherein the medium supply device is a medium supplying device.

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