Power transmission device, control method thereof, medium conveying device, recording device

Abstract

The present application relates to a power transmission device, a control method thereof, a medium conveying device, and a recording device. If a clutch is opened after a motor is started, a backlash of a gear disappears and a meshing sound occurs when teeth of the gear mesh with each other. The power transmission device includes a drive source, a power transmission switching section capable of switching to a transmission state in which power of the drive source is transmitted to a driven section and a non-transmission state in which power of the drive source is not transmitted to the driven section, a load switching section capable of switching to a first load state in which a load is a load when the driven section is driven and a second load state in which the load is smaller than the first load state, and a control section that controls the drive source, the power transmission switching section, and the load switching section. When the load is in the second load state, the control section switches the power transmission switching section from the non-transmission state to the transmission state, and then switches the load from the second load state to the first load state by the load switching section.

Description

TECHNICAL FIELD

[0001] The present application relates to a power transmission device that transmits power of a driving source to a driven portion. In addition, the present application relates to a medium conveying device that includes the power transmission device. In addition, the present application relates to a recording device that includes the medium conveying device. In addition, the present application relates to a control method of the power transmission device and a control method of the medium conveying device. BACKGROUND

[0002] In a printer, a scanner of a sheet feeding type, or the like, a roller pair composed of a driving roller and a driven roller is provided on a medium conveying path. As shown in Patent Document 1, the driven roller is sometimes configured to be able to advance and retreat with respect to the driving roller.

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 10-35938 SUMMARY

[0004] When a clutch is provided in a driving force transmission path from a motor to a driving roller, and switching of driving force transmission from the motor to the driving roller is performed, if the clutch is set to be open after the motor is started, backlash of a gear disappears and a meshing sound occurs when teeth of the gear mesh with each other.

[0005] To solve the above-described technical problem, the power transmission device of the present application is characterized by including: a driving source; a power transmission switching portion that is able to switch to a transmission state in which power of the driving source is transmitted to a driven portion and a non-transmission state in which power of the driving source is not transmitted to the driven portion; a load switching portion that is able to switch to a first load state and a second load state, the load in the first load state being a load when the driven portion is driven, the load in the second load state being smaller than the load in the first load state; and a control portion that controls the driving source, the power transmission switching portion, and the load switching portion, the control portion switching the power transmission switching portion from the non-transmission state to the transmission state when the load is in the second load state, and then switching the load from the second load state to the first load state by the load switching portion.

[0006] In addition, the medium conveying device of the present application is characterized by including the above-described power transmission device and a medium conveying path that conveys a medium, the driven portion being a driving roller that imparts a conveying force to the medium in the medium conveying path.

[0007] In addition, the recording device of the present application is characterized by including the above-described medium conveying device and a recording portion that records a conveyed medium.

[0008] Further, the control method of the power transmission device of the present application is characterized in that the power transmission device is provided with a drive source, a power transmission switching section capable of switching to a transmission state of transmitting the power of the drive source to a driven section and a non-transmission state of not transmitting the power of the drive source to the driven section, and a load switching section capable of switching to a first load state and a second load state, the load in the first load state being a load when the driven section is driven, the load in the second load state being smaller than the load in the first load state, and in the control method of the power transmission device, the power transmission switching section is switched from the non-transmission state to the transmission state while the load is in the second load state, and then the load is switched from the second load state to the first load state by the load switching section.

[0009] Further, the control method of the medium conveying device of the present application is characterized in that the medium conveying device is provided with a drive source, a power transmission switching section capable of switching to a transmission state of transmitting the power of the drive source to a drive roller and a non-transmission state of not transmitting the power of the drive source to the drive roller, and a load switching section capable of switching to a first load state and a second load state, the load in the first load state being a load when the drive roller is driven, the load in the second load state being smaller than the load in the first load state, and in the control method of the medium conveying device, when a plurality of media is continuously conveyed, the power transmission switching section is switched from the non-transmission state to the transmission state while the load is in the second load state, and then the load is switched from the second load state to the first load state by the load switching section and a first medium of the plurality of media is conveyed, the power transmission switching section is switched from the transmission state to the non-transmission state after the first medium is conveyed by a predetermined amount, the load is set to the first load state and kept constant thereafter, and the switching of the power transmission switching section from the non-transmission state to the transmission state and from the transmission state to the non-transmission state is performed every time a medium is conveyed.

[0010] Further, the control method of the medium conveying apparatus of the present application is characterized in that the medium conveying apparatus is provided with a drive source, a power transmission switching section capable of switching to a transmission state of transmitting the power of the drive source to a drive roller and a non-transmission state of not transmitting the power of the drive source to the drive roller, and a load switching section capable of switching to a first load state and a second load state, the load in the first load state being a load when the drive roller is driven, the load in the second load state being smaller than the load in the first load state, and in the control method of the medium conveying apparatus, when a plurality of media are continuously conveyed, the following controls are executed every time a medium is conveyed: a first control of switching the power transmission switching section from the non-transmission state to the transmission state while the load is in the second load state, and then switching the load from the second load state to the first load state by the load switching section; a second control of switching the power transmission switching section from the transmission state to the non-transmission state after the media are conveyed by a predetermined amount; and a third control of switching the load from the first load state to the second load state by the load switching section. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 A diagram showing a medium conveying path of a printer.

[0012] Figure 2 A diagram showing a configuration of a power transmission device.

[0013] Figure 3 A flowchart showing a first embodiment of control executed by a control section.

[0014] Figure 4 A timing chart showing the first embodiment of control executed by the control section.

[0015] Figure 5 A flowchart showing a second embodiment of control executed by the control section.

[0016] Figure 6 A timing chart showing the second embodiment of control executed by the control section.

[0017] Figure 7 A flowchart showing a third embodiment of control executed by the control section.

[0018] Figure 8 A timing chart showing the third embodiment of control executed by the control section.

[0019] Figure 9 A diagram showing another configuration of a power transmission device.

[0020] REFERENCE SIGNS

[0021] 1: inkjet printer; 2: device main body; 3: first medium cassette; 4: second medium cassette; 5: third medium cassette; 6: additional unit; 8: discharge tray; 10A, 10B, 10C, 10D: ink containing portion; 11A, 11B, 11C, 11D: mounting portion; 12: waste liquid containing portion; 13: conveyance belt; 14, 15: pulley; 19: feed roller; 20: separation roller; 21, 22, 23: pickup roller; 25, 26, 27: feed roller pair; 28, 29, 31, 32, 33, 34, 35, 36, 37, 38: conveyance roller pair; 39: roller support member; 41: baffle; 43: head unit; 44: line head; 50A, 50B: power transmission device; 53: conveyance motor; 54: pinion; 55, 56, 57, 58, 59, 60, 61, 62: gear; 65, 66, 67: shaft; 70: electromagnetic clutch; 71: solenoid; 72: control section; T1: recording-time conveyance path; T2: diversion path; T3: reversal path. DETAILED DESCRIPTION

[0022] The present application will be described below.

[0023] The first aspect relates to a power transmission device characterized by including: a drive source; a power transmission switching section capable of switching to a transmission state of transmitting power of the drive source to a driven section and a non-transmission state of not transmitting the power of the drive source to the driven section; a load switching section capable of switching to a first load state and a second load state, the load in the first load state being a load when the driven section is driven, the load in the second load state being smaller than the load in the first load state; and a control section that controls the drive source, the power transmission switching section, and the load switching section, the control section switching the power transmission switching section from the non-transmission state to the transmission state when the load is in the second load state, and then switching the load from the second load state to the first load state by the load switching section.

[0024] According to the present aspect, because the control section switches the power transmission switching section from the non-transmission state to the transmission state when the load is in the second load state in which the load is smaller than in the first load state, the meshing sound of the teeth of the two gears meshing with each other when the power transmission switching section is switched from the non-transmission state to the transmission state can be suppressed.

[0025] The second aspect is characterized in that, in the first aspect, the load switching section is constituted by a solenoid.

[0026] According to the present aspect, because the load switching section is constituted by a solenoid, the load switching section can be realized by a simple configuration.

[0027] The third aspect is characterized in that, in the first or second aspect, the power transmission switching section is constituted by an electromagnetic clutch.

[0028] According to the present aspect, since the power transmission switching section is constituted by an electromagnetic clutch, the power transmission switching section can be realized by a simple configuration.

[0029] The fourth aspect relates to a medium conveying device characterized by including the power transmission device according to any one of the first to third aspects and a medium conveying path that conveys a medium, the driven section being a drive roller that imparts a conveying force to the medium in the medium conveying path.

[0030] According to the present aspect, in the medium conveying device, the effects of any one of the first to third aspects can be obtained.

[0031] The fifth aspect is characterized in that, in the fourth aspect, a driven roller that is capable of advancing and retreating with respect to the drive roller is included, the load switching section forms the first load state by bringing the driven roller into contact with the drive roller, and forms the second load state by separating the driven roller from the drive roller.

[0032] According to the present aspect, in the configuration that switches the first load state and the second load state by advancing and retreating the driven roller with respect to the drive roller, the effects of the fourth aspect can be obtained.

[0033] The sixth aspect is characterized in that, in the fourth aspect, a medium support section that supports a medium before feeding is included, the drive roller is a pickup roller that is capable of advancing and retreating with respect to the medium supported by the medium support section, and the load switching section forms the first load state by bringing the pickup roller into contact with the medium, and forms the second load state by separating the pickup roller from the medium.

[0034] According to the present aspect, in the configuration that switches the first load state and the second load state by advancing and retreating the pickup roller with respect to the medium supported by the medium support section, the effects of the fourth aspect can be obtained.

[0035] The seventh aspect is characterized in that, in the fifth or sixth aspect, when a plurality of media is continuously conveyed, the control section switches the power transmission switching section from the non-transmission state to the transmission state while the load is in the second load state, then switches the load from the second load state to the first load state by the load switching section and conveys a first medium of the plurality of media, after conveying the first medium by a predetermined amount, the control section switches the power transmission switching section from the transmission state to the non-transmission state, and for a second medium and the media thereafter of the plurality of media, the control section sets the load to the first load state and keeps it unchanged, and every time a medium is conveyed, the switching of the power transmission switching section from the non-transmission state to the transmission state and from the transmission state to the non-transmission state is performed.

[0036] According to the present aspect, for a second medium and the media thereafter of the plurality of media, the control section sets the load to the first load state and keeps it unchanged, so it is possible to suppress the generation of sound by the load switching section and thereby improve quietness.

[0037] The eighth aspect is characterized in that, in the fifth or sixth aspect, when a plurality of media is continuously conveyed, every time a medium is conveyed, the control section performs the following controls: a first control of switching the power transmission switching section from the non-transmission state to the transmission state while the load is in the second load state, then switching the load from the second load state to the first load state by the load switching section; a second control of switching the power transmission switching section from the transmission state to the non-transmission state after conveying a medium by a predetermined amount; and a third control of switching the load from the first load state to the second load state by the load switching section.

[0038] According to the present aspect, because every time a medium is conveyed, the control section performs the switching of the power transmission switching section and the switching of the load by the load switching section, it is possible to shorten the period during which a high load acts on the drive source, and it is possible to suppress the wear of the components that constitute the power transmission path from the drive source to the driven section.

[0039] The ninth aspect is characterized in that, in the fifth or sixth aspect, when a plurality of media is continuously conveyed, the control section switches the power transmission switching section from the non-transmission state to the transmission state while the load is in the second load state, then switches the load from the second load state to the first load state by the load switching section and conveys a first medium of the plurality of media, after conveying the first medium by a predetermined amount, the control section switches the load from the first load state to the second load state by the load switching section, and for a second medium and thereafter of the plurality of media, the control section sets the power transmission switching section to the transmission state and keeps it unchanged, and the switching of the load switching section from the second load state to the first load state and from the first load state to the second load state is performed every time a medium is conveyed.

[0040] According to the present aspect, for a second medium and thereafter of the plurality of media, the control section sets the power transmission switching section to the transmission state and keeps it unchanged, so it is possible to suppress the generation of sound by the power transmission switching section and thereby improve quietness.

[0041] The tenth aspect is characterized in that, in any one of the seventh to ninth aspects, the drive source is a motor, and when conveying the first medium, the control section sets the speed of the motor to a first speed at the time of switching the power transmission switching section from the non-transmission state to the transmission state while the load is in the second load state, sets the speed of the motor to a second speed faster than the first speed after switching the load from the second load state to the first load state by the load switching section, and conveys a medium at the second speed.

[0042] According to the present aspect, because the control section sets the speed of the motor to a first speed slower than the second speed at the time of switching the power transmission switching section from the non-transmission state to the transmission state while the load is in the second load state when conveying the first medium, it is possible to further suppress the meshing sound of the teeth of the two gears meshing with each other at the time of switching the power transmission switching section from the non-transmission state to the transmission state.

[0043] The eleventh aspect is directed to a recording apparatus characterized by comprising: the medium conveying apparatus according to any one of the fourth to tenth aspects; and a recording section that records a conveyed medium.

[0044] According to the present aspect, in the recording apparatus, the effects of any one of the above-described fourth to tenth aspects can be obtained.

[0045] The twelfth aspect relates to a control method of a power transmission apparatus, the power transmission apparatus including a drive source, a power transmission switching section capable of switching between a transmission state in which the drive source transmits power to a driven section and a non-transmission state in which the drive source does not transmit power to the driven section, and a load switching section capable of switching between a first load state in which a load is a load when the driven section is driven and a second load state in which the load is smaller than the load in the first load state, the control method of the power transmission apparatus including switching the power transmission switching section from the non-transmission state to the transmission state while the load is in the second load state, and then switching the load from the second load state to the first load state by the load switching section.

[0046] According to the twelfth aspect, since the power transmission switching section is switched from the non-transmission state to the transmission state while the load is in the second load state, the meshing sound of the teeth of the two gears meshing with each other when the power transmission switching section is switched from the non-transmission state to the transmission state can be suppressed.

[0047] The thirteenth aspect relates to a control method of a medium conveying apparatus, the control method of the medium conveying apparatus including the control method of the power transmission apparatus according to the twelfth aspect, and the driven section is a drive roller, when a plurality of media is continuously conveyed, the power transmission switching section is switched from the non-transmission state to the transmission state while the load is in the second load state, then the load is switched from the second load state to the first load state by the load switching section and a first medium of the plurality of media is conveyed, after the first medium is conveyed by a predetermined amount, the power transmission switching section is switched from the transmission state to the non-transmission state, and then the load is set to the first load state and kept constant, and the switching of the power transmission switching section from the non-transmission state to the transmission state and from the transmission state to the non-transmission state is performed every time a medium is conveyed.

[0048] In other words, the control method of the medium conveying device according to the thirteenth aspect is characterized in that the medium conveying device includes a drive source, a power transmission switching section capable of switching between a transmission state in which the drive source transmits power to a drive roller and a non-transmission state in which the drive source does not transmit power to the drive roller, and a load switching section capable of switching between a first load state in which a load is a load when the drive roller is driven and a second load state in which the load is smaller than the load in the first load state, and in the control method of the medium conveying device, when a plurality of media is continuously conveyed, the power transmission switching section is switched from the non-transmission state to the transmission state while the load is in the second load state, then the load is switched from the second load state to the first load state by the load switching section and a first medium of the plurality of media is conveyed, the power transmission switching section is switched from the transmission state to the non-transmission state after the first medium is conveyed by a predetermined amount, and thereafter the load is set to the first load state and remains unchanged, and the switching of the power transmission switching section from the non-transmission state to the transmission state and the switching of the power transmission switching section from the transmission state to the non-transmission state are performed every time a medium is conveyed.

[0049] According to the present aspect, because the power transmission switching section is switched from the non-transmission state to the transmission state while the load is in the second load state, the meshing sound of the teeth of the two gears meshing with each other when the power transmission switching section is switched from the non-transmission state to the transmission state can be suppressed.

[0050] In addition, for a second medium and media subsequent to the second medium of the plurality of media, the load is set to the first load state and remains unchanged, so the sound generated by the load switching section can be suppressed and thus the quietness can be improved.

[0051] The control method of the medium conveying device according to the fourteenth aspect is characterized in that, in the control method of the medium conveying device according to the twelfth aspect, the driven section is a drive roller, and when a plurality of media is continuously conveyed, the following controls are performed every time a medium is conveyed: first control in which the power transmission switching section is switched from the non-transmission state to the transmission state while the load is in the second load state, and then the load is switched from the second load state to the first load state by the load switching section; second control in which the power transmission switching section is switched from the transmission state to the non-transmission state after a medium is conveyed by a predetermined amount; and third control in which the load is switched from the first load state to the second load state by the load switching section.

[0052] In other words, the fourteenth aspect relates to a control method of a medium conveying apparatus, the medium conveying apparatus including a drive source, a power transmission switching section capable of switching between a transmission state in which the drive source transmits power to a drive roller and a non-transmission state in which the drive source does not transmit power to the drive roller, and a load switching section capable of switching between a first load state in which a load is a load when the drive roller is driven and a second load state in which the load is smaller than the load in the first load state, the control method of the medium conveying apparatus including, when a plurality of media is continuously conveyed, performing, each time a medium is conveyed, a first control of switching the power transmission switching section from the non-transmission state to the transmission state while the load is in the second load state and then switching the load from the second load state to the first load state by the load switching section, a second control of switching the power transmission switching section from the transmission state to the non-transmission state after the medium is conveyed by a predetermined amount, and a third control of switching the load from the first load state to the second load state by the load switching section.

[0053] According to the present aspect, because the power transmission switching section is switched from the non-transmission state to the transmission state while the load is in the second load state, the meshing sound of the teeth of the two gears meshing with each other when the power transmission switching section is switched from the non-transmission state to the transmission state can be suppressed.

[0054] In addition, because the state of the power transmission switching section is switched and the load switching section switches the load each time a medium is conveyed, the load acting on the drive source can be suppressed.

[0055] The present application will be described in detail below.

[0056] An inkjet printer 1 that records by ejecting ink, which is an example of a liquid, from a recording sheet, which is an example of a medium, will be described below as an example of a recording apparatus. Hereinafter, the inkjet printer 1 will be simply referred to as the printer 1. Note that the printer 1 is also an example of a medium conveying apparatus because it conveys a medium.

[0057] The X-Y-Z coordinate system shown in the drawings is an orthogonal coordinate system, the Y-axis direction is a direction that intersects the conveying direction of the medium, i.e., the medium width direction, and is also the apparatus depth direction. The +Y direction in the Y-axis direction is a direction from the front surface of the apparatus toward the back surface of the apparatus, and the -Y direction is a direction from the back surface of the apparatus toward the front surface of the apparatus.

[0058] The X-axis direction is the device width direction, and the +X direction is the left side and the -X direction is the right side when viewed by the operator of the printer 1. The Z-axis direction is the vertical direction, which is the normal direction of the placement surface G of the printer 1, that is, the device height direction. The +Z direction in the Z-axis direction is the upper side, and the -Z direction is the lower side.

[0059] Hereinafter, the direction in which the medium is fed is sometimes referred to as "downstream", and the opposite direction thereof is sometimes referred to as "upstream". In addition, in the Figure 1 Figure 1 In the printer 1, the medium is transported through the medium transport path shown by the broken line.

[0060] In addition, the F-axis direction is the medium transport direction in the recording region between the line head 44 described later and the transport belt 13, and the +F direction is the downstream of the transport direction, and the opposite -F direction is the upstream of the transport direction. In addition, the V-axis direction is a direction orthogonal to the F-axis direction.

[0061] Next, the medium transport path in the printer 1 will be described with reference to Figure 1 The medium transport path in the printer 1 will be described. The printer 1 is configured so that the additional unit 6 can be attached to the lower portion of the device main body 2, Figure 1 The state in which the additional unit 6 is attached is shown.

[0062] The device main body 2 has a first medium cassette 3 that accommodates a medium in the lower portion, and a second medium cassette 4 and a third medium cassette 5 are also provided in the lower portion when the additional unit 6 is attached. Each of the medium cassettes is an example of a medium support portion that supports a medium before feeding.

[0063] A pickup roller that feeds the accommodated medium in the -X direction is provided for each of the medium cassettes. The pickup rollers 21, 22, and 23 are pickup rollers that are provided for the first medium cassette 3, the second medium cassette 4, and the third medium cassette 5, respectively, and are configured to be able to advance and retreat with respect to the medium accommodated in each of the medium cassettes.

[0064] In addition, a feeding roller pair that feeds the medium fed in the -X direction upward obliquely is provided for each of the medium cassettes. The feeding roller pairs 25, 26, and 27 are feeding roller pairs that are provided for the first medium cassette 3, the second medium cassette 4, and the third medium cassette 5, respectively.

[0065] Note that hereinafter, "a roller pair" is used as a roller pair that is composed of a drive roller that imparts a transport force to a medium by being driven by a drive source, and a driven roller that rotates in response to contact with the drive roller or the medium, unless otherwise specified.

[0066] The medium fed from the third medium cassette 5 is fed to the transport roller pair 38 by the transport roller pair 29, 28. In addition, the medium fed from the second medium cassette 4 is fed to the transport roller pair 38 by the transport roller pair 28. The medium is gripped by the transport roller pair 38 and fed to the transport roller pair 31.​

[0067] The media fed out from the first media cassette 3 is fed by the feed roller pair 25 to the conveyance roller pair 31 without passing through the conveyance roller pair 38.

[0068] Note that the supply roller 19 and the separation roller 20 provided in the vicinity of the conveyance roller pair 38 are omitted from the illustration of the roller pair that feeds out the media from the supply tray. Figure 1

[0069] The media subjected to the conveyance force from the conveyance roller pair 31 is fed to a position between the line head 44 as an example of the recording head and the conveyance belt 13, that is, a position opposite to the line head 44. Note that hereinafter, the media conveyance path from the conveyance roller pair 31 to the conveyance roller pair 32 is referred to as a recording-time conveyance path T1.

[0070] The line head 44 constitutes the head unit 43. The line head 44 ejects ink to the surface of the media to perform recording. The line head 44 is an ink ejection head configured to eject ink over the entire range of the media width direction, and is an ink ejection head configured to be able to perform recording over the entire range of the media width without accompanying movement in the media width direction. However, the ink ejection head is not limited thereto, and can be a type that is mounted to a carriage that moves in the media width direction while ejecting ink.

[0071] The head unit 43 is provided to be able to advance and retreat with respect to the recording-time conveyance path T1, and is provided to be able to move between a recording position that enters the recording-time conveyance path T1 to record the media and a retreat position that retreats from the recording-time conveyance path T1.

[0072] Figure 1 A state in which the head unit 43 is in the recording position in which the media is recorded is shown.

[0073] Reference numerals 10A, 10B, 10C, and 10D are ink containing portions as liquid containing portions. Ink ejected from the line head 44 is supplied to the line head 44 from each of the ink containing portions by a pipe that is omitted from the illustration. The ink containing portions 10A, 10B, 10C, and 10D are respectively provided to be able to be attached and detached to and from the mounting portions 11A, 11B, 11C, and 11D.

[0074] In addition, reference numeral 12 is a waste liquid containing portion that stores ink as a waste liquid that is ejected from the line head 44 toward a flushing cover that is not illustrated in order to perform maintenance.

[0075] ​The conveyance belt 13 is an endless belt wound around the pulley 14 and the pulley 15, at least one of which is driven to rotate by a motor not shown. The medium is conveyed in a state of being adsorbed to the surface of the conveyance belt 13 at a position opposite to the line head 44. The adsorption of the medium to the conveyance belt 13 can employ a known adsorption method such as air suction or electrostatic adsorption.

[0076] Here, the conveyance path Tl at the position opposite to the line head 44 is configured to convey the medium upward while crossing both the horizontal direction and the vertical direction. Thus, the V-axis direction as the moving direction of the head unit 43 also crosses both the horizontal direction and the vertical direction, and the inclination angle a of the V-axis direction with respect to the horizontal direction is less than 45°, more specifically, approximately 15°.

[0077] Note that the V-axis direction is not limited to the above configuration, and can be parallel to the horizontal direction.

[0078] The medium on which recording has been performed by the line head 44 on the first surface is sent further upward by the conveyance roller pair 32 located downstream of the conveyance belt 13.

[0079] A baffle 41 is provided downstream of the conveyance roller pair 32, and the conveyance direction of the medium is switched by the baffle 41. When the medium is directly discharged, the conveyance path of the medium is switched by the baffle 41 to the conveyance roller pair 35 toward the upper side, and the medium is discharged toward the discharge tray 8 by the conveyance roller pair 35.

[0080] When recording is performed on the second surface in addition to the first surface of the medium, the conveyance direction of the medium is switched by the baffle 41 to the branch position Kl. Then, the medium passes through the branch position Kl and enters the turning path T2. In the present embodiment, the turning path T2 is configured as the medium conveyance path from the upper side of the branch position Kl. The conveyance roller pairs 36 and 37 are provided in the turning path T2. The medium that has entered the turning path T2 is conveyed upward by the conveyance roller pairs 36 and 37, and then, after the lower edge of the medium has passed through the branch position Kl, the rotation direction of the conveyance roller pairs 36 and 37 is switched, whereby the medium is conveyed downward.

[0081] The turning path T3 is connected to the turning path T2. In the present embodiment, the turning path T3 is configured as the medium conveyance path from the branch position Kl to the conveyance roller pair 38 via the conveyance roller pairs 33 and 34.

[0082] The medium conveyed downward from the branch position Kl reaches the conveyance roller pair 38 from the conveyance roller pairs 33 and 34 by the conveyance force, is bent and turned over, and is sent to the conveyance roller pair 31.

[0083] The second surface of the medium, which is the side opposite to the first surface on which recording has been performed, that is again fed to the position opposite to the line head 44, is opposed to the line head 44. Thus, the second surface of the medium can be recorded by the line head 44.

[0084] Next, the description will be made with reference to Figure 2 The power transmission device 50A is described. The power transmission device 50A has a conveyance motor 53 as an example of a drive source, and a drive roller 31a as an example of a driven portion that is driven by the conveyance motor 53. In addition, the power transmission device 50A has an electromagnetic clutch 70 as an example of a power transmission switching portion that can be switched to a transmission state in which the drive roller 31a is transmitted with the power of the conveyance motor 53 and a non-transmission state in which the drive roller 31a is not transmitted with the power of the conveyance motor 53. The electromagnetic clutch 70 becomes the above-described non-transmission state by being OFF, and becomes the above-described transmission state by being ON. In addition, the power transmission device 50A has a solenoid 71 as an example of a load switching portion that can be switched to a first load state in which the load is the load when the drive roller 31a is driven, and a second load state in which the load is smaller than the load of the first load state.

[0085] In addition, the power transmission device 50A has a control portion 72 that controls the conveyance motor 53, the electromagnetic clutch 70, and the solenoid 71.

[0086] The control portion 72 has a non-volatile memory not shown in the drawing, in which a program for realizing the control described later and parameters and the like required for executing the program are stored.

[0087] The drive roller 31a is a roller that constitutes a conveyance roller pair 31 (refer to Figure 1 ). The conveyance roller pair 31 is constituted by the drive roller 31a and a driven roller 31b that can be advanced and retreated with respect to the drive roller 31a. However, it can also be constituted so that the drive roller 31a can be advanced and retreated with respect to the driven roller 31b. The conveyance roller pair 31 conveys the medium by rotating the drive roller 31a in a state in which the medium is sandwiched by the drive roller 31a and the driven roller 31b. Figure 2 In the drawing, a state in which the driven roller 31b is advanced with respect to the drive roller 31a is shown by a solid line, and a state in which the driven roller 31b is retreated from the drive roller 31a is shown by a dashed line.

[0088] The advancing and retreating operation of the driven roller 31b with respect to the drive roller 31a is performed by the solenoid 71. When the solenoid 71 is ON (energized), the driven roller 31b is advanced with respect to the drive roller 31a and abuts against the drive roller 31a, and when the solenoid 71 is OFF (de-energized), the driven roller 31b is retreated from the drive roller 31a.

[0089] The load when the drive roller 31a is driven in a state where the driven roller 31b is in abutment with the drive roller 31a is a first load state. When the driven roller 31b retreats from the drive roller 31a, the load becomes a second load state that is smaller than the first load state.

[0090] Note that the load switching section can be other configurations as long as it can switch to the first load state and the second load state. For example, it can be configured by a rack and pinion mechanism that operates by a motor.

[0091] The drive force of the conveyance motor 53 is sequentially transmitted to the pinion 54, the gear 55, the gear 56, and the gear 57. The drive force of the conveyance motor 53 transmitted to the gear 57 is transmitted to the shaft 65 by the electromagnetic clutch 70. The gear 57 and the drive roller 31a are both provided to the shaft 65, but in Figure 2 In the figure, the positions are shown to be shifted for easy illustration.

[0092] The electromagnetic clutch 70 switches, under the control of the control section 72, to a transmission state (clutch ON) in which the drive force of the conveyance motor 53 is transmitted to the drive roller 31a and a non-transmission state (clutch OFF) in which the drive force of the conveyance motor 53 is not transmitted to the drive roller 31a by transmitting the rotation of the gear 57 to the shaft 65.

[0093] Note that the power transmission switching section can be other configurations as long as it can switch to the transmission state in which the drive force of the conveyance motor 53 is transmitted to the drive roller 31a and the non-transmission state in which the drive force of the conveyance motor 53 is not transmitted to the drive roller 31a. For example, one of two gears that can be engaged can be configured to be displaceable and configured to switch the engaged state and the non-engaged state by the power of a motor, a solenoid, or the like.

[0094] First Embodiment

[0095] Next, a first embodiment of the control performed on the control section 72 will be described. The first embodiment of the control method of the power transmission device 50A and the control method of the printer 1 as a medium conveyance device or a recording device is implemented by the control shown in Figure 3 , Figure 4 Figure 3 and Figure 4 .

[0096] In the print standby state, the electromagnetic clutch 70 is OFF, and in addition, the solenoid 71 is OFF and the driven roller 31b retreats from the drive roller 31a. In addition, the conveyance motor 53 does not operate, that is, the conveyance motor 53 is stopped.

[0097] ​When a plurality of media is conveyed from this state and the first sheet (first page) is conveyed, the control section 72 starts the conveyance motor 53 (step S101), and sets the electromagnetic clutch 70 to ON (step S102). This timing is timing Tl of Figure 4 . Note that the start of the conveyance motor 53 and the ON of the electromagnetic clutch 70 can be simultaneous or either one can precede.

[0098] Then, after a waiting time wt (msec) (step S103), the solenoid 71 is set to ON to bring the driven roller 31b into abutment with the drive roller 31a (step S104, timing T2). That is, after the electromagnetic clutch 70 is set to ON and waits for a predetermined time, the solenoid 71 is set to ON.

[0099] The waiting time wt (msec) is the time required for the play between the gears in the power transmission device 50A to close so that the teeth abut each other, and is preferably set as short as possible within this range.

[0100] Next, the control section 72 sets the electromagnetic clutch 70 to OFF if it judges that the leading end of the medium has been conveyed to a predetermined position (YES in step S105). The predetermined position of step S105 can be set, for example, to a position at which the conveyance belt 13 is attracted or a nip position of the conveyance roller pair 32. A medium detection sensor not shown is provided at a position upstream and downstream of the line head 44 opposite the conveyance belt 13, and the control section 72 can grasp the position of the leading end of the medium based on the detection information of the medium detection sensor.

[0101] Then, the control section 72 repeats steps S104 to S107 (NO in step S107) until the last page. If the last page is reached (YES in step S107), the control section 72 stops the conveyance motor 53 (step S108), and sets the solenoid 71 to OFF to retreat the driven roller 31b from the drive roller 31a (step S109). This timing is timing Te of Figure 4 . Note that the stop of the conveyance motor 53, the OFF of the solenoid 71, and the OFF of the electromagnetic clutch 70 can be simultaneous or either one can precede.

[0102] As described above, because the load at the time of driving the drive roller 31a is in the second load state, that is, the state in which the driven roller 31b is separated from the drive roller 31a, the control section 72 switches the electromagnetic clutch 70 from the non-transmission state (clutch OFF) to the transmission state (clutch ON), and then, by the solenoid 71, switches the load to the first load state, that is, the state in which the driven roller 31b is in abutment with the drive roller 31a, so the meshing sound of the teeth of the two gears meshing with each other at the time of switching the electromagnetic clutch 70 from the non-transmission state (clutch OFF) to the transmission state (clutch ON) can be suppressed.

[0103] In addition, in the present embodiment, the driven roller 31b, which is a driven section, performs driven rotation by being in abutment with the drive roller 31a, which is a driven section, and the driven roller 31b is displaceable to a first position (position in abutment with the drive roller 31a) that forms the above-described first load state and a second position (position separated from the drive roller 31a) that forms the above-described second load state by the solenoid 71, which is an example of a displacement mechanism. In addition, when the driven roller 31b is in the above-described second position, the control section 72 switches the electromagnetic clutch 70 from the non-transmission state (clutch OFF) to the transmission state (clutch ON). Thereby, the meshing sound of the teeth of the two gears meshing with each other at the time of switching the electromagnetic clutch 70 from the non-transmission state (clutch OFF) to the transmission state (clutch ON) can be suppressed.

[0104] In addition, as described above, when the load is in the second load state, the control section 72 switches the electromagnetic clutch 70 from the non-transmission state (clutch OFF) to the transmission state (clutch ON) (step S102), and then, by the solenoid 71, switches the load from the second load state to the first load state (step S104) and conveys the first sheet of the plurality of sheets of media (first page). Then, after the first sheet of media is conveyed by a predetermined amount (YES in step S105), the electromagnetic clutch 70 is switched from the transmission state (clutch ON) to the non-transmission state (clutch OFF) (step S106), the load is set to the first load state and remains unchanged for the second sheet of media and the media thereafter (second page and the media thereafter), and the switching of the electromagnetic clutch 70 from the non-transmission state (clutch OFF) to the transmission state (clutch ON) and the switching from the transmission state (clutch ON) to the non-transmission state (clutch OFF) are performed each time the media is conveyed (steps S104 to S107).

[0105] Thus, for the second sheet and the sheets thereafter among the plurality of sheets, the load is set to the first load state and kept constant until the conveyance of all the sheets is completed, so that the generation of sound by the solenoid 71 can be suppressed, thereby improving the quietness.

[0106] Note that, in the conveyance of the second sheet and the sheets thereafter, since the state in which the gear backlash is closed is maintained, the meshing sound at the time when the gear backlash is closed does not occur.

[0107] Second Embodiment

[0108] Referring to Figure 5 、 Figure 6 A second embodiment of the control of the control section 72 will be described. The second embodiment of the control method of the power transmission device 50A and the control method of the printer 1 as a medium conveyance device or a recording device is realized by the control shown in Figure 5 and Figure 6 .

[0109] Since the steps S201 to S205 in Figure 5 are the same as the steps S101 to S105 in Figure 3 , the description thereof is omitted.

[0110] After the leading end of the medium is conveyed to the predetermined position (Yes in step S205), the control section 72 sets the electromagnetic clutch 70 to OFF (step S206). Then, the solenoid 71 is set to OFF to retreat the driven roller 31b from the drive roller 31a (step S207). Note that, the step S206 and the step S207 can be performed simultaneously or either one of them can be performed first.

[0111] In the present embodiment, the control section 72 repeats the steps S202 to S208 until the last page (No in step S208). If the last page is reached (Yes in step S208), the control section 72 stops the conveyance motor 53 (step S209, timing Te).

[0112] In Figure 6 , the timings T5, Tn are timings at which the same processing as the timing T1 is performed, and the timings T6, Tn+1 are timings at which the same processing as the timing T2 is performed (n is an integer).

[0113] Note that, in the present embodiment, at the timing Te, the stop of the conveyance motor 53, the OFF of the solenoid 71, and the OFF of the electromagnetic clutch 70 can be simultaneous or either one of them can be performed first.

[0114] In the present embodiment, because the load at the time of driving the drive roller 31a is in the second load state, that is, the state in which the driven roller 31b is separated from the drive roller 31a, the control section 72 switches the electromagnetic clutch 70 from the non-transmission state (clutch OFF) to the transmission state (clutch ON), and then, by the solenoid 71, switches the load to the first load state, that is, the state in which the driven roller 31b is in abutment with the drive roller 31a, so the meshing sound of the teeth of the two gears meshing with each other at the time of switching the electromagnetic clutch 70 from the non-transmission state (clutch OFF) to the transmission state (clutch ON) can also be suppressed.

[0115] In addition, as described above, each time a sheet of medium is conveyed, the control section 72 performs the following controls: first control (steps S202, S203, S204) of switching the electromagnetic clutch 70 from the non-transmission state (clutch OFF) to the transmission state (clutch ON) at the time when the load is in the second load state, and then, by the solenoid 71, switching the load from the second load state to the first load state; second control (step S206) of switching the electromagnetic clutch 70 from the transmission state (clutch ON) to the non-transmission state (clutch OFF) after conveying the medium by a predetermined amount; and third control (step S207) of switching the load from the first load state to the second load state by the solenoid 71. Thereby, the wear of the components constituting the power transmission path from the conveyance motor 53 to the drive roller 31a can be suppressed.

[0116] Third Embodiment

[0117] Next, a third embodiment of the control performed by the control section 72 will be described with reference to Figure 7 , Figure 8 A third embodiment of the control method of the power transmission device 50A and the control method of the printer 1 as a medium conveyance device or a recording device is realized by the control shown in Figure 7 and Figure 8 .

[0118] Since steps S301 to S305 in Figure 7 are the same as steps S101 to S105 in Figure 3 , the description thereof is omitted.

[0119] After the leading end of the medium is conveyed to the predetermined position (YES in step S305), the control section 72 sets the solenoid 71 to OFF to retreat the driven roller 31b from the drive roller 31a (step S306).

[0120] In this embodiment, the control unit 72 repeats steps S304 to S307 until the last page (which is not the case in step S307). If the last page is reached (which is the case in step S307), the control unit 72 sets the electromagnetic clutch 70 to OFF (step S308), and then stops the conveyor motor 53 (step S309, timing Te).

[0121] It should be noted that in this embodiment, when timing Te, the stopping of the conveyor motor 53, the OFF of the solenoid 71, and the OFF of the electromagnetic clutch 70 can be simultaneous, or any one of them can be prioritized.

[0122] In this embodiment, since the load when driving the drive roller 31a is in the second load state, that is, the driven roller 31b is separated from the drive roller 31a, the control unit 72 switches the electromagnetic clutch 70 from the non-transmission state (clutch off) to the transmission state (clutch on) and then switches the load to the first load state, that is, the driven roller 31b is in contact with the drive roller 31a, the meshing sound of the two gears meshing with each other when the electromagnetic clutch 70 is switched from the non-transmission state (clutch off) to the transmission state (clutch on) can also be suppressed.

[0123] In addition, in this embodiment, as described above, for the second and subsequent media in a plurality of media, the control unit 72 sets the electromagnetic clutch 70 to the transmission state (clutch open (ON)) and keeps it unchanged. Whenever the media is transported, the control unit 72 performs a switch from the second load state to the first load state (step S304) and a switch from the first load state to the second load state (step S306) via the solenoid 71.

[0124] Therefore, the noise generated by the electromagnetic clutch 70 can be suppressed, thereby improving quietness.

[0125] In addition, since no meshing noise occurs when the gear teeth close for the second and subsequent media, this also improves quietness.

[0126] Next, refer to Figure 9 Other embodiments of the power transmission device will be described. It should be noted that, in Figure 9 China and reference Figure 2 The same components are described using the same reference numerals, and repeated descriptions are omitted below.

[0127] In the power transmission apparatus 50B related to the present embodiment, an example of the driven section driven by the conveyance motor 53 and the drive roller is the pick-up roller 21. The pick-up roller 21 is supported by the roller support member 39 that is able to swing about the shaft 67, and advances and retreats relative to the medium P in conjunction with the swing of the roller support member 39. In Figure 9 A state in which the pick-up roller 21 shown in a solid line advances relative to the uppermost medium P and comes into abutment with the medium P is shown in FIG. 7, and a reference numeral 21-1 shows the pick-up roller 21 that has retreated from the medium P.

[0128] The power of the conveyance motor 53 is transmitted to the gear 57 via the pinion 54, the gear 55, and the gear 56, and then transmitted to the shaft 66 via the electromagnetic clutch 70. The gear 57 and the gear 58 are both provided to the shaft 66, but in Figure 9

[0129] The gear 58 is engaged with the gear 59, and the gear 59 transmits the power to the gear 60 via the shaft 67. The gear 59 and the gear 60 are both provided to the shaft 67, but in Figure 9

[0130] The power transmitted to the gear 60 is transmitted to the pick-up roller 62 via the gear 61 and the gear 62.

[0131] The electromagnetic clutch 70 switches, under the control of the control section 72, between a transmission state (clutch ON) in which the rotation of the gear 57 is transmitted to the shaft 66 to transmit the power of the conveyance motor 53 to the pick-up roller 21 and a non-transmission state (clutch OFF) in which the power of the conveyance motor 53 is not transmitted to the pick-up roller 21.

[0132] The swing operation of the roller support member 39 is performed by the solenoid 71. In the ON (energized) state of the solenoid 71, the pick-up roller 21 comes into abutment with the uppermost medium P by the weight thereof. If the solenoid 71 becomes the OFF (non-energized) state, the roller support member 39 is pulled upward to retreat from the uppermost medium P. Note that the relationship between the ON and the OFF of the solenoid 71 can be reversed, i.e., the pick-up roller 21 can be configured to retreat from the uppermost medium P by being pulled upward in the ON (energized) state of the solenoid 71, and come into abutment with the uppermost medium P in the OFF (non-energized) state of the solenoid 71.

[0133] ​​The load when the pickup roller 21 is driven in the state of abutting against the uppermost medium P is a first load state. If the pickup roller 21 retreats from the uppermost medium P, a second load state in which the load is smaller than the first load state is established. As a result, it is seen that the abutting state of the pickup roller 21 against the medium P affects the load when the pickup roller 21 is driven.

[0134] In the present embodiment, the control described with reference to the first embodiment, or the control described with reference to the second embodiment, or the control described with reference to the third embodiment can be adopted. Figure 3 Figure 4 In the present embodiment, the control described with reference to the first embodiment, or the control described with reference to the second embodiment, or the control described with reference to the third embodiment can be adopted. Figure 5 Figure 6 In the present embodiment, the control described with reference to the first embodiment, or the control described with reference to the second embodiment, or the control described with reference to the third embodiment can be adopted. Figure 7 Figure 8 In the present embodiment, the control described with reference to the first embodiment, or the control described with reference to the second embodiment, or the control described with reference to the third embodiment can be adopted.

[0135] That is, in the present embodiment, the pickup roller 21 as an example of a driven portion is displaced by the solenoid 71 as an example of a displacement mechanism between a first position in which the above-described first load state is established and which is in contact with the uppermost medium P and a second position in which the above-described second load state is established and which retreats from the uppermost medium P. Further, when the pickup roller 21 is in the above-described second position, the control portion 72 switches the electromagnetic clutch 70 from the non-transmission state (clutch OFF) to the transmission state (clutch ON). As a result, it is possible to suppress the meshing sound in which the teeth of the two gears mesh with each other when the electromagnetic clutch 70 is switched from the non-transmission state (clutch OFF) to the transmission state (clutch ON).

[0136] Note that, in the above-described first embodiment, or the second embodiment, or the third embodiment, it is also possible that, when the electromagnetic clutch 70 is switched from the non-transmission state (clutch OFF) to the transmission state (clutch ON) at the time when the load when the driven portion is driven is in the second load state when the first medium is transported, the control portion 72 sets the speed of the transport motor 53 to the first speed, and sets the speed of the transport motor 53 to the second speed which is faster than the first speed after the above-described load is switched from the second load state to the first load state by the solenoid 71, and transports the medium at the second speed. As a result, it is possible to further suppress the meshing sound in which the teeth of the two gears mesh with each other when the electromagnetic clutch 70 is switched from the non-transmission state (clutch OFF) to the transmission state (clutch ON).

[0137] ​​​Further, in the first embodiment, or the second embodiment, or the third embodiment, although the driven portion is provided as the drive roller 31a constituting the transport roller pair 31, it is not limited thereto, and can be provided as a drive roller constituting another transport roller pair or a drive roller constituting a feed roller pair. Further, in the first embodiment, or the second embodiment, or the third embodiment, the driven portion is provided as the pickup roller 21, but it is not limited thereto, and can be another pickup roller (22, 23), a pickup roller for manually feeding out a tray not shown.

[0138] Further, the present application is not limited to the above-described embodiments, modifications, and can be variously modified within the scope of the application recited in the claims, and of course, these are included in the scope of the present application.

Claims

1. A media transport apparatus, characterized by, Possessing: a drive source; a power transmission switching section capable of switching to a transmission state of transmitting power of the drive source to a driven section and a non-transmission state of not transmitting the power of the drive source to the driven section; a load switching section capable of switching to a first load state and a second load state, a load in the first load state being a load at the time of driving the driven section, a load in the second load state being smaller than the load in the first load state; a control section that controls the drive source, the power transmission switching section, and the load switching section; and a medium conveying path that conveys a medium, when the load is in the second load state, the control section switches the power transmission switching section from the non-transmission state to the transmission state, and then switches the load from the second load state to the first load state by the load switching section, the driven section is a driving roller that imparts a conveying force to the medium in the medium conveying path, when a plurality of media is continuously conveyed, when the load is in the second load state, the control section switches the power transmission switching section from the non-transmission state to the transmission state, and then switches the load from the second load state to the first load state by the load switching section and conveys a first medium among the plurality of media; the control section switches the power transmission switching section from the transmission state to the non-transmission state after conveying the first medium by a predetermined amount; for a second medium and a medium thereafter among the plurality of media, the control section sets the load switching section to the first load state and keeps it unchanged, and every time a medium is conveyed, switching of the power transmission switching section from the non-transmission state to the transmission state and from the transmission state to the non-transmission state is performed.

2. A media transport apparatus, characterized by, Possessing: a drive source; a power transmission switching section capable of switching to a transmission state of transmitting power of the drive source to a driven section and a non-transmission state of not transmitting the power of the drive source to the driven section; a load switching section capable of switching to a first load state and a second load state, a load in the first load state being a load at the time of driving the driven section, a load in the second load state being smaller than the load in the first load state; a control section that controls the drive source, the power transmission switching section, and the load switching section; a medium conveying path that conveys a medium, when the load is in the second load state, the control section switches the power transmission switching section from the non-transmission state to the transmission state, and then switches the load from the second load state to the first load state by the load switching section, the driven section is a driving roller that imparts a conveying force to the medium in the medium conveying path, when a plurality of media is continuously conveyed, every time a medium is conveyed, the control section performs the following control: a first control, when the load is in the second load state, the control section switches the power transmission switching section from the non-transmission state to the transmission state, and then switches the load from the second load state to the first load state by the load switching section; second control, after a predetermined amount of the medium is transported, switching the power transmission switching section from the transmission state to the non-transmission state; and third control, switching a load from the first load state to the second load state by the load switching section.

3. A media transport apparatus, characterized by, provided with: a drive source; a power transmission switching section capable of switching to a transmission state in which the drive source transmits power to a driven section and a non-transmission state in which the drive source does not transmit power to the driven section; a load switching section capable of switching to a first load state and a second load state, the load in the first load state being a load when the driven section is driven, the load in the second load state being smaller than the load in the first load state; a control section that controls the drive source, the power transmission switching section, and the load switching section; a medium transport path that transports a medium, when the load is in the second load state, the control section switches the power transmission switching section from the non-transmission state to the transmission state, and then switches a load from the second load state to the first load state by the load switching section, the driven section is a drive roller that imparts a conveying force to a medium in the medium transport path, when a plurality of media is continuously transported, when the load is in the second load state, the control section switches the power transmission switching section from the non-transmission state to the transmission state, and then switches a load from the second load state to the first load state by the load switching section and transports a first medium of the plurality of media; the control section, after a predetermined amount of the first medium is transported, switches a load from the first load state to the second load state by the load switching section; for a second medium and media thereafter of the plurality of media, the control section sets the power transmission switching section to the transmission state and keeps it unchanged, and switches the load switching section from the second load state to the first load state and from the first load state to the second load state each time a medium is transported.

4. The medium transport apparatus according to any one of claims 1 to 3, wherein the load switching section is constituted by a solenoid.

5. The medium transport apparatus according to any one of claims 1 to 3, wherein the power transmission switching section is constituted by an electromagnetic clutch.

6. The medium transport apparatus according to any one of claims 1 to 3, wherein the medium transport apparatus is provided with a driven roller that is capable of advancing and retreating with respect to the drive roller, the load switching section forms the first load state by bringing the driven roller into contact with the drive roller, and forms the second load state by separating the driven roller from the drive roller.

7. The medium transport apparatus according to any one of claims 1 to 3, wherein the medium transport apparatus is provided with a medium support section that supports a medium before feeding, the drive roller is a pickup roller that is capable of advancing and retreating with respect to a medium supported by the medium support section, The load switching section forms the first load state by bringing the pick-up roller into contact with the medium and forms the second load state by bringing the pick-up roller out of contact with the medium.

8. The medium conveying apparatus according to any one of claims 1 to 3, wherein the drive source is a motor, when conveying a first medium, the control section sets the speed of the motor to a first speed at the time of switching the power transmission switching section from the non-transmission state to the transmission state while the load is in the second load state, after switching the load from the second load state to the first load state by the load switching section, the speed of the motor is set to a second speed faster than the first speed and the medium is conveyed at the second speed.

9. A recording apparatus, characterized by comprising: provided with: the medium conveying apparatus according to any one of claims 1 to 8; and a recording section that records on the conveyed medium.

10. A control method of a power transmission apparatus, characterized by the power transmission apparatus provided with: a drive source; a power transmission switching section that is switchable to a transmission state in which the drive source's power is transmitted to a driven section and a non-transmission state in which the drive source's power is not transmitted to the driven section; and a load switching section that is switchable to a first load state and a second load state, the load in the first load state being a load when the driven section is driven, the load in the second load state being smaller than the load in the first load state, in the control method of the power transmission apparatus, when the load is in the second load state, the power transmission switching section is switched from the non-transmission state to the transmission state, and then the load is switched from the second load state to the first load state by the load switching section, the driven section is a drive roller that imparts a conveyance force to a medium, when a plurality of media is continuously conveyed, the power transmission switching section is switched from the non-transmission state to the transmission state while the load is in the second load state, and then the load is switched from the second load state to the first load state by the load switching section and a first medium in the plurality of media is conveyed, after the first medium is conveyed by a predetermined amount, the power transmission switching section is switched from the transmission state to the non-transmission state, the load switching section is set to the first load state and remains unchanged thereafter, and the switching of the power transmission switching section from the non-transmission state to the transmission state and from the transmission state to the non-transmission state is performed every time a medium is conveyed.

11. A control method of a power transmission apparatus, characterized by the power transmission apparatus provided with: a drive source; a power transmission switching section that is switchable to a transmission state in which the drive source's power is transmitted to a driven section and a non-transmission state in which the drive source's power is not transmitted to the driven section; and a load switching section that is switchable to a first load state and a second load state, the load in the first load state being a load when the driven section is driven, the load in the second load state being smaller than the load in the first load state, in the control method of the power transmission apparatus, The control method of the power transmission device, The power transmission switching section is switched from the non-transmission state to the transmission state when the load is in the second load state, and then the load is switched from the second load state to the first load state by the load switching section, The driven section is a driving roller that imparts a conveying force to a medium, When a plurality of media is continuously conveyed, the following control is executed each time a medium is conveyed: First control, the power transmission switching section is switched from the non-transmission state to the transmission state when the load is in the second load state, and then the load is switched from the second load state to the first load state by the load switching section; Second control, the power transmission switching section is switched from the transmission state to the non-transmission state after the medium is conveyed by a predetermined amount; And Third control, the load is switched from the first load state to the second load state by the load switching section.

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