printer

Abstract

To solve the problem in which: there is a possibility that through-put is reduced when continuously performing printing on a plurality of media.SOLUTION: A printer 1 includes: a feeding roller 5 which conveys a medium P from a storage section 2 for storing the medium P, the feeding roller 5 being provided in a feeding path RF to be the downstream side of the storage section 2 in a conveying direction in which the medium P is conveyed; an intermediate roller 8 which is provided at a position which is the downstream side of the feeding roller 5 in the feeding path RF and conveys the medium P; and a first motor 7 which rotates the feeding roller 5 and the intermediate roller 8 through a power transmission section 51. The power transmission section 51 has a connection section in a transmission path TP for transmitting power of the first motor 7 to the intermediate roller 8. The connection section allows the intermediate roller 8 to rotate in accordance with external force when the external force for rotating the intermediate roller 8 in a direction in which the medium P is conveyed to the downstream side is applied.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a printing apparatus.

Background Art

[0002] Patent Document 1 discloses a printing apparatus including a supply roller, an intermediate roller, a printing roller, a first motor, a second motor, a switching gear mechanism, and a control unit. The supply roller supplies a printing medium from a storage unit that stores the printing medium to a conveyance path. The intermediate roller is disposed in the conveyance path and conveys the printing medium. The printing roller is disposed in a printing path that is located downstream of the conveyance path and performs a printing process on the printing medium, and conveys the printing medium. The first motor rotates the supply roller and the intermediate roller. The second motor rotates the printing roller. The switching gear mechanism switches between rotating the supply roller and the intermediate roller or rotating the intermediate roller according to the rotation direction of the first motor. The control unit executes a first conveyance mode in which the supply and conveyance of the printing medium are performed by rotating the first motor in a predetermined direction, and a second conveyance mode in which the conveyance of the printing medium is performed by rotating the first motor in the reverse direction of the predetermined direction.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] For example, in the printing apparatus of Patent Document 1, it is assumed that the control unit switches the conveyance mode from the second conveyance mode to the first conveyance mode in order to feed the next printing medium during the printing process on the printing medium conveyed in the second conveyance mode. When switching the conveyance mode from the second conveyance mode to the first conveyance mode, there is a moment when the rotation of the intermediate roller stops. In this case, the conveyance of the printing medium being printed is hindered at the moment when the rotation of the intermediate roller stops, and it is easy for the print quality to deteriorate and for conveyance failures to occur. Therefore, when feeding the next printing medium during the printing process, it is necessary to switch the conveyance mode from the second conveyance mode to the first conveyance mode after the conveyance of the printing medium being printed by the intermediate roller is completed. As a result, the timing to start feeding the next printing medium is delayed, and there is a risk that the throughput when printing multiple printing media in succession will decrease.

Means for Solving the Problems

[0005] The printing apparatus includes a feed roller that conveys the medium from a storage unit that stores the medium, the feed roller being provided in a conveyance path downstream of the storage unit in the conveyance direction in which the medium is conveyed, an intermediate roller provided at a position downstream of the feed roller in the conveyance path and that conveys the medium, a printing roller provided at a position downstream of the intermediate roller, the printing roller conveying the medium toward a medium support unit on which printing is performed on the medium, a first motor that rotates the feed roller and the intermediate roller via a power transmission unit, the power transmission unit that transmits the power of the first motor to the feed roller and the intermediate roller, and a second motor that rotates the printing roller. The power transmission unit has a connection part in a transmission path that transmits the power of the first motor to the intermediate roller, and the connection part allows the intermediate roller to rotate according to the external force when an external force that rotates the intermediate roller in the direction in which the medium is conveyed downstream acts.

Brief Description of the Drawings

[0006]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0007] Hereinafter, the present disclosure will be described based on embodiments. In each figure, the same members are denoted by the same reference numerals, and redundant descriptions are omitted. In this specification, "the same", "identical", and "simultaneous" do not only refer to being completely the same. For example, in this specification, "the same", "identical", and "simultaneous" include cases where they are the same considering measurement errors. For example, in this specification, "the same", "identical", and "simultaneous" include cases where they are the same considering manufacturing variations of members.

[0008] For example, in this specification, "the same", "identical", and "simultaneous" include cases where they are the same within a range that does not impair the function. Thus, for example, "the dimensions of both are the same" means that considering measurement errors and manufacturing variations of members, the dimensional difference between the two is within ±5 percent, particularly preferably within ±3 percent, of one of the dimensions.

[0009] 1. Embodiment 1 The printing apparatus 1 is, for example, an inkjet printer capable of printing on a single-sheet printing paper or the like, which is an example of the medium P.

[0010] In each figure, X, Y, and Z represent three mutually perpendicular spatial axes. In this specification, the directions along these axes are referred to as the X-axis direction, the Y-axis direction, and the Z-axis direction. When specifying a direction, the positive direction is denoted as "+", the negative direction as "-", and the positive and negative signs are used in combination in the direction notation. The direction in which the arrow in each figure points is the + direction, and the opposite direction of the arrow is the - direction for explanation.

[0011] Also, the Z-axis direction indicates the direction of gravity, with the +Z direction being vertically upward and the -Z direction being vertically downward. Also, the plane including the X-axis and Y-axis is the X-Y plane, the plane including the X-axis and Z-axis is the X-Z plane, and the plane including the Y-axis and Z-axis is the Y-Z plane for explanation. Also, the X-Y plane is the horizontal plane. Furthermore, for the three spatial axes X, Y, and Z without limiting the positive and negative directions, they are described as the X-axis, the Y-axis, and the Z-axis.

[0012] The X-axis direction is the width direction of the printing device 1 and the width direction of the medium P on which printing is performed. Looking from the operator located on the front side of the printing device 1, the +X direction is the right side and the -X direction is the left side.

[0013] The Y-axis direction is the depth direction of the printing device 1 and the direction along the conveyance direction of the medium P during printing. The +Y direction is the direction from the front to the back of the printing device 1, and the -Y direction is the direction from the back to the front of the printing device 1. In this embodiment, among the side surfaces constituting the periphery of the printing device 1, the side surface in the -Y direction is the front surface of the printing device 1, and the side surface in the +Y direction is the back surface of the printing device 1.

[0014] Hereinafter, the direction in which the medium P is sent is referred to as "downstream", and the opposite direction is referred to as "upstream".

[0015] Hereinafter, with reference to FIG. 1, the constituent members of the printing device 1 will be described along the conveyance path TR provided in the printing device 1. The conveyance path TR is composed of a feeding path RF, a supply path RS, a discharge path RD, and a return path RR. The feeding path RF, the supply path RS, the discharge path RD, and the return path RR are examples of the conveyance path TR.

[0016] As shown in FIG. 1, the printing apparatus 1 includes a cassette-type storage unit 2 at the bottom of the apparatus. The storage unit 2 stores the medium P. The storage unit 2 is detachably provided from the front side of the apparatus.

[0017] The printing apparatus 1 includes a pick roller 3 driven by a first motor 7 via a power transmission unit 51 above the storage unit 2. The power transmission unit 51 will be described later. The pick roller 3 can move forward and backward with respect to the medium P stored in the storage unit 2. The pick roller 3 rotates in contact with the medium P stored in the storage unit 2, thereby feeding the medium P from the storage unit 2 in the +Y direction.

[0018] The printing apparatus 1 includes a feed roller 5 and a separation roller 6 to which rotational torque is applied by a torque limiter (not shown) in a feed path RF downstream of the storage unit 2. The feed roller 5 is driven by a first motor 7 via the power transmission unit 51. The medium P fed out from the storage unit 2 is separated by being nipped between the feed roller 5 and the separation roller 6, and is conveyed downstream of the feed roller 5 and the separation roller 6 in the feed path RF.

[0019] The printing apparatus 1 includes a medium detection unit 24 at a position downstream of the feed roller 5 and the separation roller 6 in the feed path RF. The medium detection unit 24 is provided so as to be able to detect whether or not the medium P has passed through a position PE which is downstream of the feed roller 5 and the separation roller 6 in the feed path RF. The position PE is an example of a predetermined position.

[0020] As the medium detection unit 24, a reflective photosensor, a transmissive photosensor, etc. arranged to be able to emit light toward the position PE can be adopted. For example, the control unit 80 described later can determine the timing of conveying the medium P to the feed path RF based on the detection information of the medium detection unit 24.

[0021] In the feeding path RF, the printing apparatus 1 includes an intermediate roller 8 at a position downstream of the feeding roller 5, the separating roller 6, and the medium detection unit 24. The intermediate roller 8 is driven by a first motor 7 via a power transmission unit 51. Around the intermediate roller 8, nip rollers 9, 10, 11 are provided. The nip rollers 9, 10 together with the intermediate roller 8 constitute a part of the feeding path RF. The nip roller 11 together with the intermediate roller 8 constitutes a part of the return path RR.

[0022] In the feeding path RF, the nip roller 10 is located downstream of the nip roller 9. The medium P is nipped between the intermediate roller 8 and the nip roller 9, and further nipped between the intermediate roller 8 and the nip roller 10, and is conveyed downstream. The conveyance direction of the medium P is reversed from the +Y direction to the -Y direction by the intermediate roller 8 and is conveyed downstream.

[0023] The printing apparatus 1 includes a medium detection unit 22 at a position downstream of the intermediate roller 8 in the feeding path RF. The medium detection unit 22 is provided at a position PL downstream of the intermediate roller 8 in the feeding path RF so as to be able to detect whether the leading end of the medium P has reached.

[0024] As the medium detection unit 22, a reflective photosensor, a transmissive photosensor, etc. that are arranged to be able to emit light toward the position PL can be adopted. For example, the control unit 80 can position the leading end of the medium P with respect to the print head 40 based on the detection information of the medium detection unit 22. Also, for example, the control unit 80 can position the medium P at the printing start position.

[0025] In addition to the feeding path RF from the housing unit 2, the printing apparatus 1 includes a supply path RS from the supply tray 12. The supply tray 12 that constitutes the supply path RS supports the medium P in an inclined posture. The printing apparatus 1 includes a supply roller 13 and a separating roller 14 in the supply path RS. The supply roller 13 is driven by a first motor 7 via a power transmission unit 51. The supply roller 13 may be driven by a supply motor (not shown).

[0026] A rotational torque is applied to the separation roller 14 by a torque limiter (not shown). The medium P supported by the supply tray 12 is conveyed by the supply roller 13 and the separation roller 14 toward the downstream feeding path RF. The supply path RS merges with the feeding path RF at a position between the nip portion formed by the intermediate roller 8 and the nip roller 10 and the medium detection unit 22 in the feeding path RF.

[0027] The printing apparatus 1 includes a printing roller pair 15 constituted by a printing roller 16 and a driven roller 17 that can be rotationally driven downstream of the intermediate roller 8 and the medium detection unit 22. The printing roller 16 is driven by a second motor 23.

[0028] For example, it is assumed that printing is being performed on the medium P. At this time, as shown in FIG. 5, when viewed from the +X direction side, the second motor 23 is rotationally driven in a direction in which the output shaft of the second motor 23 rotates clockwise. Thereby, when viewed from the +X direction side, the printing roller 16 rotates counterclockwise, and the medium P is conveyed toward the medium support portion 18 downstream of the printing roller pair 15.

[0029] The printing apparatus 1 includes a medium support portion 18 at a position downstream of the printing roller pair 15. The medium support portion 18 supports the medium P conveyed by the printing roller pair 15. By supporting the medium P, the medium support portion 18 defines a gap between the ejection surface 42a of the printing head 40 described later and the medium P. Hereinafter, the gap between the medium P and the ejection surface 42a may be referred to as a printing gap. Printing on the medium P by the printing head 40 described later is performed at the medium support portion 18.

[0030] The printing apparatus 1 includes a print head 40 at a position on the +Z direction side of the medium support portion 18. The print head 40 includes a plurality of nozzles 44 on a discharge surface 42a facing the surface of the medium support portion 18 that supports the medium P. The print head 40 performs printing by discharging ink from the plurality of nozzles 44 onto the medium P supported by the medium support portion 18. Ink is an example of a liquid.

[0031] The print head 40 is a so-called line head in which a plurality of nozzles 44 for discharging ink are arranged so as to cover the entire region in the medium width direction along the X-axis direction. The print head 40 is configured as a liquid discharge head that is long in the medium width direction and can perform printing over the entire medium width without moving in the medium width direction.

[0032] The discharge surface 42a faces the medium P supported by the medium support portion 18. The discharge surface 42a can also be referred to as a liquid discharge surface or a nozzle surface. The printing apparatus 1 includes a liquid storage portion (not shown). The ink discharged from the print head 40 is supplied to the print head 40 from the liquid storage portion via a supply tube (not shown).

[0033] The print head 40 is movably provided in the direction of advancing and retreating with respect to the medium support portion 18, that is, in the direction of adjusting the printing gap, by a gap adjustment mechanism (not shown). In the present embodiment, the direction of adjusting the printing gap is a direction along the Z-axis direction.

[0034] The printing apparatus 1 includes a pair of post-feed rollers 19 at a position downstream of the medium support portion 18. The pair of post-feed rollers 19 includes a post-feed roller 20 driven by a post-feed motor (not shown) and a driven roller 21 that can rotate passively. The medium P on which printing has been performed is conveyed toward a discharge path RD downstream of the pair of post-feed rollers 19 by driving the post-feed roller 20. The driving of the post-feed roller 20 may be performed by a second motor 23 via a power transmission mechanism (not shown).

[0035] The printing apparatus 1 includes a switching flap 26 in the discharge path RD. The switching flap 26 is provided in the discharge path RD so as to be movable between a discharge position shown by a solid line in FIG. 1 and a return position shown by a two-dot chain line when an actuator (not shown) is driven.

[0036] The discharge position is a position when the medium P is conveyed to the downstream discharge path RD by the rotational drive of the rear feed roller 20. The return position is a position when the medium P conveyed to the discharge path RD is conveyed toward the return path RR. As the actuator for moving the switching flap 26 to the discharge position and the return position, for example, an electromagnetic solenoid or the like can be adopted.

[0037] The printing apparatus 1 includes a pair of transfer rollers 27 at a position downstream of the switching flap 26 in the discharge path RD. The printing apparatus 1 includes a pair of discharge rollers 28 at a position downstream of the pair of transfer rollers 27 in the discharge path RD. The pair of transfer rollers 27 and the pair of discharge rollers 28 are rotatable in one direction when the medium P is conveyed in the discharge direction and in the other direction when the medium P is conveyed in the return direction by being driven by a discharge motor (not shown).

[0038] When the pair of transfer rollers 27 and the pair of discharge rollers 28 rotate in one direction, the medium P in the discharge path RD is conveyed in the discharge direction toward a discharge tray 29 provided downstream of the discharge path RD. The medium P on which printing has been performed and which is conveyed in the discharge direction is discharged to the discharge tray 29 by the pair of discharge rollers 28 with the most recent printing surface being the lower surface which is a surface in the -Z direction.

[0039] When the pair of transfer rollers 27 and the pair of discharge rollers 28 rotate in the other direction, the medium P in the discharge path RD is conveyed in the return direction toward the return path RR.

[0040] The return path RR is a path through which the medium P is conveyed when double-sided printing is performed to print on both sides of the medium P. The return path RR connects between the pair of transfer rollers 27 and a nip portion formed by the intermediate roller 8 and the nip roller 9.

[0041] The printing apparatus 1 includes a pair of return rollers 25 in a return path RR. For example, when performing double-sided printing on the medium P, the pair of return rollers 25 is driven by a return motor (not shown). The pair of return rollers 25 conveys the medium P conveyed from the discharge path RD to the return path RR toward a nip portion that constitutes the return path RR and is formed by the nip roller 11 and the intermediate roller 8.

[0042] At this time, the medium P is conveyed by the pair of return rollers 25 with the printed surface printed previously facing upward, which is the surface on the +Z direction side. In the return path RR, the medium P conveyed by the pair of return rollers 25 is nipped by the rotating intermediate roller 8 and nip roller 11. The medium P nipped by the intermediate roller 8 and nip roller 11 is conveyed toward a nip portion formed by the downstream intermediate roller 8 and nip roller 9.

[0043] The medium P nipped by the rotating intermediate roller 8 and nip roller 9 is conveyed downstream of the nip portion formed by the intermediate roller 8 and nip roller 9. The medium P conveyed again to the feed path RF is conveyed toward the medium support portion 18 by the intermediate roller 8, nip roller 10, and the pair of printing rollers 15. At this time, the medium P is conveyed toward the medium support portion 18 with the printed surface printed previously facing downward, which is the surface on the -Z direction side.

[0044] With the printed surface printed previously facing downward, printing is performed on the medium P conveyed to the medium support portion 18 by the print head 40, thereby performing double-sided printing on the medium P. The medium P on which double-sided printing has been performed passes through the pair of rear feed rollers 19 and the switching flap 26 at the discharge position, and is conveyed to the discharge path RD.

[0045] The medium P conveyed to the discharge path RD is conveyed in the discharge direction toward the pair of discharge rollers 28 by the pair of transfer rollers 27. The medium P on which double-sided printing has been performed is discharged to the discharge tray 29 by the pair of discharge rollers 28 with the most recently printed surface facing downward, which is the surface on the -Z direction side.

[0046] The printing apparatus 1 includes a power transmission unit 51. The power transmission unit 51 transmits the power of the first motor 7 to the intermediate roller 8, the feed roller 5, and the pick roller 3. The power transmission unit 51 is provided so that the power transmission destination of the first motor 7 can be switched according to the rotation direction of the output shaft of the first motor 7. The power transmission unit 51 in the present embodiment also transmits the power of the first motor 7 to the supply roller 13.

[0047] As shown in FIG. 5, when the output shaft of the first motor 7 rotates clockwise when viewed from the +X direction side, the conveyance of the medium P by the first motor 7 and the power transmission unit 51 is referred to as a conveyance mode. As shown in FIG. 4, when the output shaft of the first motor 7 rotates counterclockwise when viewed from the +X direction side, the conveyance of the medium P by the first motor 7 and the power transmission unit 51 is referred to as a feed mode.

[0048] In FIGS. 4 to 7, among the medium P, the conveyed medium P is shown as the previous medium Pp. In FIG. 7, among the medium P, the medium P conveyed following the previous medium Pp is shown as the next medium Pn. In FIGS. 4 to 7, when the rotation direction of each roller is indicated by a black arrow, it represents that the roller is rotating passively due to an external force or the like acting thereon.

[0049] Hereinafter, the rotation of the output shaft of the first motor 7 clockwise is referred to as "the first motor 7 rotates clockwise". The rotation of the output shaft of the first motor 7 counterclockwise is referred to as "the first motor 7 rotates counterclockwise". In the rotation direction of the output shaft of the first motor 7, clockwise is an example of one direction, and counterclockwise is an example of the other direction.

[0050] As shown in FIG. 5, in the conveyance mode in which the first motor 7 rotates clockwise, the power transmission unit 51 transmits the power of the first motor 7 to the intermediate roller 8. As a result, the intermediate roller 8 and the nip rollers 9, 10 rotate in the direction of the arrow, and the medium P in the feed path RF is conveyed downstream in the direction of the arrow.

[0051] As shown in FIG. 4, in the feeding mode in which the first motor 7 rotates counterclockwise, the power transmission unit 51 transmits the power of the first motor 7 to the intermediate roller 8, the feeding roller 5, and the pick-up roller 3. As a result, the pick-up roller 3, the feeding roller 5, and the separation roller 6 rotate in the direction of the arrow, and the medium P is conveyed from the accommodating unit 2 toward the downstream in the direction of the arrow.

[0052] As shown in FIG. 2, the power transmission unit 51 has a transmission path TP for transmitting the power of the first motor 7 to the intermediate roller 8. The transmission path TP is constituted by a gear train 52 including a plurality of gears, a drive shaft 53, a one-way clutch 54, and the like.

[0053] The drive shaft 53 is rotatably provided about an axis along the X-axis. An intermediate roller 8 is provided at the end of the drive shaft 53 on the +X direction side. By transmitting the power of the first motor 7 from the gear train 52, the drive shaft 53 and the intermediate roller 8 rotate about the axis.

[0054] The one-way clutch 54 may be provided, for example, in the gear train 52 in the transmission path TP. However, the one-way clutch 54 of the present embodiment is provided between the intermediate roller 8 and the drive shaft 53.

[0055] When an external force that rotates the intermediate roller 8 acts in the direction in which the medium P is conveyed downstream (see FIG. 6), the one-way clutch 54 allows the intermediate roller 8 to rotate according to the external force. At this time, the intermediate roller 8 rotates with respect to the drive shaft 53 with the drive shaft 53 as the rotation axis according to the external force. The one-way clutch 54 is an example of a connection part that the power transmission unit 51 has in the transmission path TP.

[0056] The one-way clutch 54 of the present embodiment is provided between an intermediate roller 8 having an outer diameter larger than that of the gears constituting the gear train 52 and the drive shaft 53. As a result, the one-way clutch 54 can be easily disposed inside the intermediate roller 8 between the intermediate roller 8 and the drive shaft 53. Therefore, since the power transmission unit 51 has the one-way clutch 54 in the transmission path TP, it is easy to suppress the increase in size of the printing apparatus 1.

[0057] For example, a roller-type non-one-way clutch having a cylindrical outer shape (see FIG. 1) can be adopted as the one-way clutch 54 of the present embodiment. In this case, the one-way clutch 54 is composed of an outer ring and an inner ring forming a cylindrical shape, a plurality of rollers and springs provided between a cam surface formed on the inner diameter surface of the outer ring and the inner ring. By fixing the outer ring of the one-way clutch 54 to the center of the intermediate roller 8 and fixing the inner ring to the drive shaft 53, the intermediate roller 8 can be attached to the drive shaft 53.

[0058] The one-way clutch 54 may be a planetary gear type including planetary gears instead of roller-type rollers and springs. In this case, teeth for causing the drive shaft 53 to function as a sun gear may be provided on the peripheral surface of the drive shaft 53 to which the one-way clutch 54 is attached.

[0059] As shown in FIG. 1, the printing apparatus 1 includes a control unit 80. The control unit 80 controls the entire printing apparatus 1. The control unit 80 may include a processor that executes various processes according to a program, a dedicated hardware circuit such as an application-specific integrated circuit that executes at least a part of the various processes, or a combination thereof.

[0060] The processor includes a CPU and memories such as a RAM and a ROM, and the memories store program codes or instructions configured to cause the CPU to execute processes. The memory, that is, the computer-readable medium, includes any readable medium accessible by a general-purpose or dedicated computer.

[0061] The control unit 80 drives and controls the first motor 7 to rotate counterclockwise, and transmits the power of the first motor 7 to the feed roller 5, the intermediate roller 8, and the pick roller 3 via the power transmission unit 51. Thereby, the control unit 80 conveys the medium P downstream from the storage unit 2 by setting the conveyance of the medium P to the feed mode.

[0062] The control unit 80 drives and controls the first motor 7 to rotate clockwise, and transmits the power of the first motor 7 to the intermediate roller 8 via the power transmission unit 51. Thereby, the control unit 80 conveys the medium P in the feed path RF downstream by setting the conveyance of the medium P to the conveyance mode.

[0063] The control unit 80 drives and controls the first motor 7, and transmits the power of the first motor 7 to the supply roller 13 via the power transmission unit 51. Thereby, the control unit 80 conveys the medium P from the supply tray 12 toward the feed path RF.

[0064] The control unit 80 drives and controls the second motor 23 to rotate the printing roller pair 15. Thereby, the control unit 80 conveys the medium P toward the medium support unit 18 located downstream of the printing roller pair 15.

[0065] The control unit 80 drives and controls the gap adjustment mechanism to adjust the printing gap. The control unit 80 drives and controls the print head 40 to eject ink from the nozzles 44 onto the medium P supported by the medium support unit 18. Thereby, the control unit 80 prints on the medium P.

[0066] The control unit 80 drives and controls the post-feed motor to rotate the post-feed roller pair 19. Thereby, the control unit 80 conveys the medium P toward the discharge path RD downstream of the post-feed roller pair 19.

[0067] The control unit 80 drives and controls the actuator to move the switching flap 26 to the discharge position. The control unit 80 drives and controls the discharge motor to rotate the transfer roller pair 27 and the discharge roller pair 28 in one direction. Thereby, the control unit 80 discharges the medium P onto the discharge tray 29 with the most recent printing surface facing downwards.

[0068] When performing double-sided printing on the medium P, the control unit 80 drives and controls the actuator to move the switching flap 26 to the return position. The control unit 80 drives and controls the discharge motor to rotate the transfer roller pair 27 and the discharge roller pair 28 in the other direction. Thereby, the control unit 80 conveys the medium P printed on one side from the discharge path RD towards the return path RR.

[0069] The control unit 80 drives and controls the return motor to rotate the return roller pair 25. Thereby, the control unit 80 conveys the medium P to the nip section between the nip roller 11 and the intermediate roller 8. The control unit 80 conveys the medium P to the feed path RF again by conveying the medium P in the conveyance mode.

[0070] The control unit 80 conveys the medium P conveyed to the feed path RF again downstream by conveying the medium P in the conveyance mode. The control unit 80 drives and controls the second motor 23 to rotate the printing roller pair 15. Thereby, the control unit 80 conveys the medium P towards the medium support section 18.

[0071] The control unit 80 drives and controls the print head 40 to perform printing on the medium P conveyed to the medium support section 18 with the previously printed printing surface facing downwards. Thereby, double-sided printing is performed on the medium P.

[0072] The control unit 80 drives and controls the reverse feed motor to rotate the reverse feed roller pair 19. Thereby, the control unit 80 conveys the double-sided printed medium P towards the discharge path RD.

[0073] The control unit 80 drives and controls the actuator to move the switching flap 26 to the discharge position. The control unit 80 drives and controls the discharge motor to rotate the transfer roller pair 27 and the discharge roller pair 28 in one direction. Thereby, the control unit 80 discharges the double-sided printed medium P onto the discharge tray 29 with the most recent printing surface facing downwards.

[0074] Next, with reference to the flowchart shown in FIG. 3, the processing executed by the control unit 80 in the feeding process of feeding the medium P from the storage unit 2 to the transport path TR will be described. In the feeding process of the present embodiment, the flow of the processing executed by the control unit 80 corresponds to the control method of the printing apparatus 1.

[0075] In step S110, the control unit 80 checks whether there is a medium P in the feeding path RF. The feeding process of feeding the medium P from the storage unit 2 to the transport path TR may be performed, as shown in FIG. 5, when printing is being performed on the previous medium Pp. Alternatively, the feeding process may be performed when there is a previous medium Pp in the feeding path RF.

[0076] Therefore, when performing the feeding process, the control unit 80 checks whether there is a medium Pp in the feeding path RF. As shown in FIG. 5, if there is a medium Pp in the feeding path RF, step S110 becomes YES, and the control unit 80 shifts the process to step S120. As shown in FIG. 1, if there is no medium Pp in the feeding path RF, step S110 becomes NO, and the control unit 80 shifts the process to step S130.

[0077] In addition, when step S110 is YES, the first motor 7 is rotationally driven clockwise in one direction. Therefore, the previous medium Pp in the feeding path RF is conveyed downstream by the intermediate roller 8. As shown in FIG. 5, when printing is being performed on the previous medium Pp, the second motor 23 is driven, and the previous medium Pp is conveyed downstream by the printing roller pair 15. When step S110 is NO, the first motor 7 is not driven.

[0078] In step S130, the control unit 80 rotationally drives the first motor 7 in the other direction, i.e., counterclockwise. Thereby, the control unit 80 changes the conveyance of the medium P to the feeding mode. As shown in FIG. 4, in the feeding mode, the power transmission unit 51 transmits the power of the first motor 7 to the intermediate roller 8, the feeding roller 5, and the pick-up roller 3.

[0079] Thereby, when the pick-up roller 3, the feeding roller 5, and the separating roller 6 rotate in the direction of the arrow, the medium P is conveyed from the accommodating unit 2 toward the downstream in the direction of the arrow. After finishing the process of step S130, the control unit 80 ends the feeding process.

[0080] In step S120, the control unit 80 checks whether the medium Pp has passed a predetermined position. That is, the control unit 80 checks whether the previous medium Pp has passed the position PE. Specifically, when the medium detection unit 24 changes from the detection state of detecting the medium P to the non-detection state of not detecting the medium P, the control unit 80 determines that the trailing end of the previous medium Pp has passed the position PE. As shown in FIG. 5, if the detection state of the medium detection unit 24 is the detection state of detecting the medium P, the control unit 80 determines that the previous medium Pp has not passed the position PE.

[0081] When the control unit 80 determines that the trailing end of the previous medium Pp has passed the position PE, step S120 becomes YES, and the control unit 80 shifts the process to step S140. When the control unit 80 determines that the previous medium Pp has not passed the position PE, step S120 becomes NO, and the control unit 80 continues to detect the medium Pp by the medium detection unit 24 in step S120.

[0082] In step S140, the control unit 80 switches the rotation direction of the first motor 7 from clockwise, which is one direction, to counterclockwise, which is the other direction. Thereby, the control unit 80 changes the conveyance of the medium P from the conveyance mode to the feeding mode. As shown in FIG. 7, in the feeding mode, the power transmission unit 51 transmits the power of the first motor 7 to the intermediate roller 8, the feeding roller 5, and the pick-up roller 3.

[0083] As a result, the pick roller 3, the feed roller 5, and the separation roller 6 rotate in the direction of the arrow, and the next medium Pn is conveyed from the accommodating portion 2 toward the downstream in the direction of the arrow. When the process of step S140 is completed, the control unit 80 ends the feeding process.

[0084] When the feeding process of the next medium Pn is completed, the control unit 80 switches the rotation direction of the first motor 7 from counterclockwise to clockwise. Thereby, the control unit 80 changes the conveyance of the medium P from the feeding mode to the conveyance mode.

[0085] In addition, in step S140, when the rotation direction of the first motor 7 is switched from clockwise to counterclockwise, as shown in FIG. 6, a timing occurs when the rotation of the first motor 7 stops. At this time, the previous medium Pp is nipped by the intermediate roller 8 and the nip rollers 9 and 10. Also, at this time, printing is being performed on the previous medium Pp by the print head 40.

[0086] In the present embodiment, a one-way clutch 54 is provided in the transmission path TP. Thereby, while suppressing an increase in the load acting on the printing roller 16, the intermediate roller 8 can be passively rotated by the rotation of the printing roller 16 due to the drive of the second motor 23. Therefore, it is possible to suppress a conveyance failure of the medium Pp due to switching the rotation direction of the first motor 7 during the conveyance of the previous medium Pp. Therefore, it is possible to suppress a decrease in print quality due to switching the rotation direction of the first motor 7 during printing on the previous medium Pp.

[0087] When printing is being performed on the medium P, due to factors different from the switching of the rotation direction of the first motor 7, fluctuations in the rotation speed of the first motor 7 or a decrease in the rotation speed of the first motor 7 may occur. Even in this case, the one-way clutch 54 allows the intermediate roller 8 to be rotated passively by the rotation of the printing roller 16 due to the drive of the second motor 23. Thereby, fluctuations in the load acting on the printing roller 16 can be suppressed. Therefore, during printing on the previous medium Pp, a decrease in print quality due to fluctuations in the rotation speed of the first motor 7, a decrease in the rotation speed of the first motor 7, etc. can be suppressed.

[0088] As described above, according to the printing apparatus 1 according to Embodiment 1, the following effects can be obtained.

[0089] The printing apparatus 1 includes a feed roller 5 that conveys the medium P from the storage unit 2 that stores the medium P, and the feed roller 5 is provided on a feed path RF that is downstream of the storage unit 2 in the conveyance direction in which the medium P is conveyed. The printing apparatus 1 includes an intermediate roller 8 provided at a position downstream of the feed roller 5 in the feed path RF and that conveys the medium P. The printing apparatus 1 includes a printing roller 16 provided at a position downstream of the intermediate roller 8 and that conveys the medium P toward the medium support unit 18 on which printing is performed on the medium P. The printing apparatus 1 includes a first motor 7 that rotates the feed roller 5 and the intermediate roller 8 via a power transmission unit 51. The printing apparatus 1 includes a power transmission unit 51 that transmits the power of the first motor 7 to the feed roller 5 and the intermediate roller 8. The power transmission unit 51 has a connection portion in a transmission path TP that transmits the power of the first motor 7 to the intermediate roller 8. The connection portion allows the intermediate roller 8 to rotate according to an external force when an external force that rotates the intermediate roller 8 in the direction in which the medium P is conveyed downstream acts.

[0090] According to this, during printing on the medium P conveyed by the printing roller 16 and the intermediate roller 8, the medium P can be conveyed from the storage unit 2 by the feed roller 5. Therefore, it is possible to suppress a decrease in throughput when printing on a plurality of media P continuously.

[0091] The power transmission unit 51 has a drive shaft 53 on the transmission path TP, on which the intermediate roller 8 is rotatably provided, and the connection part is provided between the intermediate roller 8 and the drive shaft 53.

[0092] According to this, compared with the case where the connection part is provided at another position on the transmission path TP, the intermediate roller 8 can be rotated in the direction in which the medium P is conveyed downstream with a small external force. Also, according to this, the connection part can be arranged inside the intermediate roller 8 between the intermediate roller 8 and the drive shaft 53. Therefore, since the power transmission unit 51 has the connection part on the transmission path TP, it is easy to suppress the enlargement of the printing apparatus 1.

[0093] The connection part is a one-way clutch 54 that allows the intermediate roller 8 to rotate in the direction in which the medium P is conveyed downstream when an external force acts on the intermediate roller 8. According to this, the connection part can be arranged on the transmission path TP with a simple configuration.

[0094] When the first motor 7 rotates clockwise, the power of the first motor 7 is transmitted to the intermediate roller 8 via the power transmission unit 51, and thereby the medium P is conveyed downstream. When the first motor 7 rotates counterclockwise, the power of the first motor 7 is transmitted to the feed roller 5 and the intermediate roller 8 via the power transmission unit 51, and thereby the medium P is conveyed downstream from the storage unit 2.

[0095] According to this, by changing the rotation direction of the first motor 7, it is possible to switch between the conveyance of the medium P downstream in the feed path RF and the conveyance of the medium P downstream from the storage unit 2.

[0096] The printing apparatus 1 further includes a control unit 80. Assume that the medium Pp downstream passes through the position PE between the feeding roller 5 and the intermediate roller 8 in the feeding path RF when the printing roller 16 and the intermediate roller 8 rotate. In this case, the control unit 80 conveys the next medium Pn from the storage unit 2 downstream by switching the rotation direction of the first motor 7 from clockwise to counterclockwise.

[0097] According to this, during printing on the previous medium Pp, the next medium Pn can be conveyed from the storage unit 2 while ensuring the interval between the previous medium Pp and the next medium Pn.

[0098] The printing apparatus 1 further includes a medium detection unit 24 at the position PE. When the medium detection unit 24 changes from the detection state of detecting the medium P to the non-detection state of not detecting the medium P, the control unit 80 determines that the medium P has passed through the position PE. According to this, it is possible to easily determine that the medium P has passed through the position PE with a simple configuration.

[0099] The printing apparatus 1 according to the above-described embodiment of the present disclosure is basically configured as described above, but it is of course possible to make partial configuration changes, omissions, etc. within the scope not departing from the gist of the present disclosure. Also, the above-described embodiment and other embodiments described below can be implemented in combination with each other as long as there is no technical contradiction. Hereinafter, other embodiments will be described.

[0100] In the above embodiment, as long as a gap can be ensured between the previous medium Pp and the next medium Pn, the position PE does not have to be the position between the feeding roller 5 and the intermediate roller 8 in the feeding path RF. For example, the position PE may be the position of the nip portion formed by the feeding roller 5 and the separating roller 6. Alternatively, the position PE may be the position between the pick-up roller 3 and the feeding roller 5.

[0101] In the above embodiment, the printing apparatus 1 may not include the medium detection unit 24. In this case, it may be determined whether or not the medium P has passed through the position PE based on the conveyance amount by which the medium P is conveyed downstream after being detected by the medium detection unit 22 and the dimension of the medium P in the conveyance direction. In this case, the position PL is an example of a preset reference position PR. Alternatively, it may be determined whether or not the medium P has passed through the position PE based on the conveyance amount by which the medium P is conveyed downstream after starting the conveyance of the medium P from the storage unit 2 and the dimension of the medium P in the conveyance direction. In this case, the position of the leading end of the medium P when it is stored in the storage unit 2 is an example of a preset reference position PR.

[0102] Alternatively, based on the conveyance amount by which the medium P is conveyed downstream after the rear end of the medium P has passed through a position between the leading end and the rear end of the medium P stored in the storage unit 2 in the Y-axis direction, it may be determined whether or not the medium P has passed through the position PE. In this case, the position between the leading end and the rear end of the medium P stored in the storage unit 2 in the Y-axis direction is an example of a preset reference position PR. In this case, a sensor may be provided at the reference position PR so as to be able to detect the medium P.

[0103] Alternatively, it may be determined whether or not the medium P has passed through the position PE based on the conveyance amount by which the medium P is conveyed downstream after starting the conveyance of the medium P from the storage unit 2. In this case, the position of the rear end of the medium P when it is stored in the storage unit 2 is an example of a preset reference position PR. In this case, a sensor may be provided at the reference position PR so as to be able to detect the medium P.

[0104] According to the printing apparatus 1 according to these embodiments, the following effects can be obtained. The control unit 80 determines whether or not the medium P has passed through the position PE based on the conveyance amount by which the medium P is conveyed downstream from the preset reference position PR. According to this, the control unit 80 can easily determine whether or not the medium P has passed through the position PE.

[0105] In the above-described embodiment, the power transmission unit 51 may not include the one-way clutch 54 in the transmission path TP. For example, the power transmission unit 51 may include an electromagnetic clutch in the transmission path TP instead of the one-way clutch 54. The electromagnetic clutch is provided in the transmission path TP such that its connection state by energization and its non-connection state by cutting off the energization to the electromagnetic clutch are switchable. In the connected state, the intermediate roller 8 and the drive shaft 53 are connected. In the non-connected state, the intermediate roller 8 is rotatable with respect to the drive shaft 53. The control unit 80 may set the conveyance of the medium P to the conveyance mode by setting the electromagnetic clutch to the connected state and set the conveyance of the medium P to the feeding mode by setting the electromagnetic clutch to the non-connected state. In this case, the electromagnetic clutch is an example of a connection portion.

Explanation of Reference Numerals

[0106] 1... printing apparatus, 2... housing portion, 3... pick-up roller, 5... feeding roller, 6... separating roller, 7... first motor, 8... intermediate roller, 9, 10, 11... nip roller, 12... supply tray, 13... supply roller, 14... separating roller, 15... printing roller pair, 16... printing roller, 17, 21... driven roller, 18... medium support portion, 19... post-feed roller pair, 20... post-feed roller, 22, 24... medium detection unit, 23... second motor, 25... return roller pair, 26... switching flap, 27... transfer roller pair, 28... discharge roller pair, 29... discharge tray, 40... print head, 42a... ejection surface, 44... nozzle, 51... power transmission unit, 52... gear train, 53... drive shaft, 54... one-way clutch, 80... control unit, S110, S120, S130, S140... step, P... medium, Pn... next medium, Pp... previous medium, PE, PL... position, PR... reference position, RD... discharge path, RF... feeding path, RR... return path, RS... supply path, TP... transmission path, TR... conveyance path.

Claims

1. A feed roller that conveys the medium from a storage unit that stores the medium, the feed roller being provided in a conveyance path downstream of the storage unit in the conveyance direction in which the medium is conveyed; An intermediate roller provided at a position downstream of the feed roller in the conveyance path, the intermediate roller conveying the medium; A printing roller provided at a position downstream of the intermediate roller, the printing roller conveying the medium toward a medium support unit on which printing is performed on the medium; A first motor that rotates the feed roller and the intermediate roller via a power transmission unit; The power transmission unit that transmits the power of the first motor to the feed roller and the intermediate roller; A second motor that rotates the printing roller; Comprising; The power transmission unit has a connection part in a transmission path that transmits the power of the first motor to the intermediate roller; The connection part allows the intermediate roller to rotate according to the external force when an external force that rotates the intermediate roller in the direction in which the medium is conveyed downstream acts; A printing apparatus characterized by the above.

2. The power transmission unit has a drive shaft on which the intermediate roller is rotatably provided in the transmission path; The connection part is provided between the intermediate roller and the drive shaft; The printing apparatus according to claim 1, characterized by the above.

3. The connection part is a one-way clutch that allows the intermediate roller to rotate in the direction in which the medium is conveyed downstream when the external force acts on the intermediate roller; The printing apparatus according to claim 1, characterized by the above.

4. When the first motor rotates in one direction, the power of the first motor is transmitted to the intermediate roller via the power transmission unit, so that the medium is conveyed downstream; When the first motor rotates in the other direction, the power of the first motor is transmitted to the feed roller and the intermediate roller via the power transmission unit, so that the medium is conveyed from the storage unit downstream; The printing apparatus according to any one of claims 1 to 3, characterized by the above.

5. Further comprising a control unit; When the printing roller and the intermediate roller rotate, when a predetermined position between the feed roller and the intermediate roller in the conveyance path is passed by the medium downstream, The control unit conveys the next medium from the storage unit toward the downstream by switching the rotation direction of the first motor from one direction to the other direction. The printing apparatus according to claim 4, characterized by the above.

6. The printing apparatus further includes a medium detection unit at the predetermined position. When the medium detection unit changes from a detection state in which the medium is detected to a non-detection state in which the medium is not detected, the control unit determines that the medium has passed through the predetermined position. The printing apparatus according to claim 5, characterized by the above.

7. The control unit determines whether or not the medium has passed through the predetermined position based on the conveyance amount by which the medium has been conveyed downstream from a preset reference position. The printing apparatus according to claim 5, characterized by the above.

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