Medium transport device and recording apparatus

A medium transport device includes a first roller that applies a transporting force to a medium, a second roller that applies a transporting force to the medium transported from the first roller, a third roller that applies a transporting force to the medium transported from the second roller, a first rotor that transmits rotational torque to the third roller, a first shaft that is provided away from the first rotor at a first interval, and a second shaft that is provided away from the first rotor at the first interval and at a position different from a position of the first shaft. A shaft center of the first shaft and a shaft center of the second shaft are positioned on a circular arc, the center of which is a rotation center of the second roller.

The present application is based on, and claims priority from JP Application Serial Number 2019-198384, filed Oct. 31, 2019, the disclosure of which is hereby incorporated by reference herein in its entirety.

BACKGROUND

1. Technical Field

The present disclosure relates to a medium transport device that transports a medium, and a recording apparatus including the medium transport device.

2. Related Art

Recording apparatuses represented by a facsimile machine, a printer, and the like may have a lineup of, from a strategic sales point of view, a plurality of models having specifications that are substantially the same but partially differ from each other. Since designing dedicated parts for each model causes an increase in costs, common parts have been used as much as possible in the related art (see JP-A-2002-103736, JP-A-2004-154974, JP-A-2004-042382, JP-A-2008-200892, and JP-A-2009-034858).

Also for a medium transport device that transports a medium, there has been a demand for using common parts as much as possible for a model including a single motor as a driving source that drives a plurality of rollers and for a model including a plurality of motors. However, when the number of motors is changed, particularly, in a transmission mechanism that transmits a driving force from a motor to a roller, the number of dedicated parts to be prepared for each model is easily increased, which inhibits a reduction in costs.

SUMMARY

According to an aspect of the present disclosure, a medium transport device includes a first roller that applies a transporting force to a medium, a second roller that applies a transporting force to the medium transported from the first roller, a third roller that applies a transporting force to the medium transported from the second roller, a third roller driving gear that transmits rotational torque to the third roller, a first shaft that is provided away from the third roller driving gear at a first interval, and a second shaft that is provided away from the third roller driving gear at the first interval and at a position different from a position of the first shaft, in which a shaft center of the first shaft and a shaft center of the second shaft are positioned on a circular arc, a center of which is a rotation center of the second roller.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, the present disclosure will be schematically described.

A medium transport device according to a first aspect includes: a first roller that applies a transporting force to a medium; a second roller that applies a transporting force to the medium transported from the first roller; a third roller that applies a transporting force to the medium transported from the second roller; a first rotor that transmits rotational torque to the third roller; a first shaft that is provided away from the first rotor at a first interval; and a second shaft that is provided away from the first rotor at the first interval and at a position different from a position of the first shaft, in which a shaft center of the first shaft and a shaft center of the second shaft are positioned on a circular arc, a center of which is a rotation center of the second roller.

According to the aspect, in the medium transport device including the first roller, the second roller, and the third roller, the first shaft and the second shaft are disposed for the first rotor that transmits rotational torque to the third roller, and thus a driving force transmission configuration can vary between when using the first shaft and when using the second shaft.

Further, the first shaft and the second shaft are disposed on the circular arc, the center of which is the rotation center of the second roller, and thus a distance between the rotation center of the second roller and the first shaft, and a distance between the rotation center of the second roller and the second shaft are kept constant. In addition, both an interval between the first shaft and the first rotor and an interval between the second shaft and the first rotor are set to the first interval.

As a result, the same component configuration can be used for the driving force transmission mechanism using a belt, a gear, or the like both the time when transmitting a driving force between the first rotor and the second roller by using the first shaft and the time when transmitting a driving force between the first rotor and the second roller by using the second shaft, such that it is possible to effectively suppress an increase in costs when developing models with different specifications.

According to a second aspect, the medium transport device according to the first aspect further includes: a second rotor that is provided on a rotation shaft of the second roller and applies rotational torque to the second roller; a belt that is wound on a third rotor provided on the first shaft or the second shaft and wound on the second rotor; a tension applying member that applies tension to the belt; a slider that supports the tension applying member and is configured to slide in a direction to advance and retreat with respect to the belt; and a pressing member that applies a pressing force to the slider, in which a first guide groove that guides the slider, and a second guide groove that extends in a direction intersecting a direction in which the first guide groove extends and that guides the slider are provided in a frame supporting the rotation shaft of the second roller.

According to the aspect, the first guide groove that guides the slider and the second guide groove that extends in the direction intersecting the direction in which the first guide groove extends and that guides the slider are provided. Therefore, it is possible to apply, in an appropriate direction, tension to the belt when the rotor is provided on the first axis and to the belt when the rotor is provided on the second shaft without increasing costs.

According to a third aspect, in the medium transport device according to the second aspect, at least one of the first shaft or the second shaft is integrated with the frame.

According to the aspect, at least one of the first shaft or the second shaft is integrated with the frame, and thus it is possible to reduce costs of the apparatus.

A recording apparatus according to a fourth aspect includes a recording unit that performs recording on a medium, and the medium transport device according to any one of first to third aspects.

According to the aspect, in the recording apparatus, effects of any of the first to third aspects can be obtained.

A recording apparatus according to a fifth aspect includes: a recording unit that performs recording on a medium; and the medium transport device according to the second or third aspect, in which the medium transport device includes: a first medium transport path which is a medium transport path facing the recording unit and is configured to transport the medium in a first direction which is a medium transport direction when performing the recording on the medium and in a second direction opposite to the first direction; a reverse path configured to reverse the medium; a second medium transport path configured to guide, to the reverse path, the medium subjected to the recording by the recording unit; and a third medium transport path which is positioned vertically below the second medium transport path, guides, to the reverse path, the medium subjected to the recording by the recording unit, and differs from the second medium transport path, the first roller is provided downstream of the recording unit on the first medium transport path and transports the medium in the first direction, the second roller is positioned downstream of the first roller in the first direction and is configured to rotate in a normal rotation direction to transport the medium transported in the first direction to a discharge port and in a reverse rotation direction opposite to the normal rotation direction, the medium being discharged from the discharge port by normal rotation of the second roller and the medium being transported to the third medium transport path by reverse rotation of the second roller, and the third roller is provided on the third medium transport path and is configured to rotate only in a normal rotation direction to transport the medium to the reverse path.

According to the aspect, it is possible to ensure, by using the third medium transport path, a path length when transporting the medium to the reverse path and facilitate double-sided recording on a long medium.

According to a sixth aspect, in the recording apparatus according to the fifth aspect, the first shaft is a rotation shaft of the first roller, the third rotor is provided on the first shaft, a first gear that meshes with a third roller driving gear as the first rotor is integrated with the third rotor, and the second roller and the third roller are driven by a first motor through the rotation shaft of the first roller.

According to the aspect, the first roller, the second roller, and the third roller can be driven by the first motor, and it is possible to reduce parts costs of the apparatus.

According to a seventh aspect, in the recording apparatus according to the fifth aspect, the first shaft is a rotation shaft of the first roller, the third rotor is provided on the second shaft, a first gear that meshes with a third roller driving gear as the first rotor is integrated with the third rotor, the first roller is driven by a first motor, and the second roller and the third roller are driven by a second motor through the first gear.

According to the aspect, the first roller is driven by the first motor, and the second roller and the third roller are driven by the second motor. Therefore, it is possible to increase a degree of freedom in control.

According to an eighth aspect, the recording apparatus according to the seventh aspect further includes a motor attaching member to which the second motor is attached, in which a shaft end of the second shaft is supported by the motor attaching member in a state in which the motor attaching member is fixed to the frame.

According to the aspect, the shaft end of the second shaft is supported by the motor attaching member in a state in which the motor attaching member is fixed to the frame, and thus it is possible to suppress deformation of the second shaft.

In each drawing, a direction along an X-axis is an apparatus width direction and is a direction intersecting a sheet transport direction, that is, a sheet width direction. A −X direction is a rightward direction when viewed by a user facing a front surface of the apparatus, and a +X direction is a leftward direction.

Further, a direction along a Y-axis is an apparatus depth direction, and a +Y direction is a direction from a rear surface of the apparatus toward the front surface and is referred to as a first direction. Further, a −Y direction is a direction from the front surface of the apparatus toward the rear surface and is referred to as a second direction.

Further, a direction along a Z axis is a vertical direction, a +Z direction is a vertically upward direction, and a −Z direction is a vertically downward direction.

In the present embodiment, among side surfaces of the apparatus, a side surface on which an operating section5is provided is the front surface of the apparatus.

InFIG. 1, an ink jet printer1, which is an example of the recording apparatus, is a multifunction peripheral including a scanner section3that is provided on upper side of an apparatus body2. Hereinafter, the ink jet printer is simply referred to as a “printer”.

The apparatus body2has a function of performing recording on a recording sheet, which is an example of the medium, and the scanner section3has a function of reading a document. Further, the scanner section3includes an auto document feeder (ADF) that automatically feeds a set document.

The apparatus body2includes a medium transport device4(seeFIG. 2) that transports a recording sheet, a transport path (to be described later) through which the recording sheet is transported, and a recording head9(seeFIG. 2) which is an example of the recording unit. In addition, in the present embodiment, two medium housing cassettes, specifically, a first sheet cassette51and a second sheet cassette52, are detachably provided.

Further, the apparatus body2is configured also to set and feed a sheet from the rear surface of the apparatus in addition to setting sheet in the first sheet cassette51and the second sheet cassette52. A cover7opens/closes a sheet setting port (not illustrated) at the time of setting a sheet from the rear surface of the apparatus.

The apparatus body2includes the operating section5that is provided on the front surface of the apparatus and used to perform various operations of the printer1. The operating section5includes a display section and a plurality of operation buttons and is provided to be tiltable.

A discharge port10through which a recording sheet subjected to recording is discharged is provided below the operating section5, and a discharge tray6that receives the discharged recording sheet is provided on a lower side of the discharge port10. The discharge tray6can be in a state of being housed in the apparatus body2as illustrated inFIG. 1and a state of being drawn out from the apparatus body2(not illustrated).

Next, the transport path for the recording sheet will be described with reference toFIG. 2. Note that the second sheet cassette52is not illustrated inFIG. 2.

In the printer1, the recording sheet is transported to a transport roller pair15via a reverse roller21constituting a reverse path RR irrespective of a feeding path and is transported by the transport roller pair15to a region where recording is performed by the recording head9.

More specifically, the printer1includes, as sheet feeding paths, a sheet feeding path K1for feeding a recording sheet from the first sheet cassette51, a sheet feeding path K2for feeding a recording sheet from the second sheet cassette52that is positioned under the first sheet cassette51, and a sheet feeding path K3for manually feeding a recording sheet from the upper-rear side of the apparatus.

Further, the printer1includes, as sheet transport paths, a first sheet transport path FR1which is a sheet transport path facing the recording head9and through which a recording sheet can be transported in the first direction (+Y direction), which is a sheet transport direction when performing recording on the recording sheet, and in the second direction (−Y direction) opposite to the first direction, the reverse path RR through which the recording sheet is reversed, a second sheet transport path FR2that guides the recording sheet subjected to the recording to the reverse path RR, and a third sheet transport path FR3that is positioned vertically below the second sheet transport path FR2and guides the recording sheet subjected to the recording to the reverse path RR, the third sheet transport path FR3being different from the second sheet transport path FR2.

Further, according to the present embodiment, the first sheet transport path FR1is a sheet transport path between the transport roller pair15and a first discharge roller pair40. Further, the second sheet transport path FR2is a sheet transport path that extends over a driven roller14dand is positioned between the transport roller pair15and a driven roller14a. Further, the third sheet transport path FR3is a sheet transport path that extends over a reverse driving roller44and is positioned between a second discharge roller pair46and the driven roller14a. Further, the reverse path RR is a sheet transport path between the driven roller14aand a driven roller14c. Further, inFIG. 2, a sheet transport path FR4is a sheet transport path (fourth sheet transport path) between the driven roller14cand the transport roller pair15. Further, a sheet transport path FR5is a sheet transport path (fifth sheet transport path) between the first discharge roller pair40and the second discharge roller pair46.

In the sheet feeding path K1, the recording sheet is fed by a feeding roller11. The feeding roller11is supported by a supporting member12that rocks about a rocking shaft12aand the feeding roller11advances and retreats with respect to a recording sheet P housed in the first sheet cassette51in response to the rocking of the supporting member12.

The same feeding mechanism (not illustrated) is provided in the second sheet cassette52(not illustrated inFIG. 2) provided under the first sheet cassette51.

The reverse roller21has the largest diameter compared with other rollers and curves and reverses the recording sheet. The driven rollers14a,14b,14c, and14dare provided around the reverse roller21. The recording sheet fed through the sheet feeding path K1or K2is transported to the transport roller pair15through the reverse path RR and the fourth sheet transporting path FR4.

The recording sheet fed through the sheet feeding path K3is transported to the transport roller pair15through the fourth sheet transporting path FR4.

The recording sheet transported in the −Y direction through the second sheet transport path FR2is transported to the transport roller pair15through the reverse path RR and the fourth sheet transporting path FR4.

Similarly, the recording sheet transported in the −Y direction through the third sheet transport path FR3is transported to the transport roller pair15through the reverse path RR and the fourth sheet transporting path FR4.

The transport roller pair15includes a transport driving roller16that rotates and a transport driven roller17that is driven to rotate. The recording sheet transported to the transport roller pair15is nipped by the transport driving roller16and the transport driven roller17, is transported to a region facing the recording head9, that is, the region where recording is performed, and is subjected to recording.

A carriage8including the recording head9is guided by a carriage guide shaft19that extends in the X-axis direction and is reciprocated in the X-axis direction by a driving force from a carriage driving motor (not illustrated). The recording head9ejects ink to the recording sheet along with a movement operation of the carriage8.

A supporting member18is provided at a position facing the recording head9, and the recording sheet subjected to recording by the recording head9is supported by the supporting member18.

The first discharge roller pair40that transports downstream the recording sheet subjected to recording is provided downstream of the supporting member18. The first discharge roller pair40includes a first discharge driving roller41as a “first roller” that rotates and a first discharge driven roller42that is driven to rotate. The first discharge driving roller41is a rubber roller in the present embodiment, and the first discharge driven roller42is a spur in point-contact with the recording sheet in the present embodiment.

The first discharge roller pair40is the roller pair positioned first downstream of the recording head9.

The second discharge roller pair46is provided downstream of the first discharge roller pair40. The second discharge roller pair46includes a second discharge driving roller47as a “second roller” that rotates and a second discharge driven roller48that is driven to rotate.

A driven roller49is provided between the first discharge roller pair40and the second discharge roller pair46and suppresses a lift of the recording sheet.

The second discharge driving roller47is a rubber roller in the present embodiment, and the second discharge driven roller48and the driven roller49are spurs in point-contact with the recording sheet in the present embodiment.

A function of the second discharge roller pair46will be described in more detail later.

Hereinafter, the second sheet transport path FR2, the third sheet transport path FR3, and the reverse path RR will further be described.

When performing recording on a second surface of a recording sheet of which a first surface has been subjected to recording, the second surface being opposite to the first surface, the recording sheet subjected to recording is transported to the reverse path RR. Any of the second sheet transport path FR2or the third sheet transport path FR3can be selected as a sheet transport path at this time.

A length of the third sheet transport path FR3is larger than a length of the second sheet transport path FR2. Therefore, a controller (not illustrated) of the printer1holds a threshold value of a sheet length, selects the third sheet transport path FR3when the length of the recording sheet exceeds the threshold value, and selects the second sheet transport path FR2when the length of the recording sheet is smaller than the threshold value. In other words, it is possible to deal with a long recording sheet by using the third sheet transport path FR3.

When using the second sheet transport path FR2, after the recording on the first surface is completed, the transport driving roller16, the first discharge driving roller41, and the second discharge driving roller47rotate in a reverse direction. By doing so, the recording sheet is transported in the −Y direction through the second sheet transport path FR2and reaches the reverse path RR.

When using the third sheet transport path FR3, after the recording on the first surface is completed, the recording sheet is transported in the +Y direction until a rear end of the sheet reaches the driven roller49, and then the second discharge driving roller47rotates in a reverse direction. A flap39that can rock about a rocking shaft39ais provided upstream of the driven roller49, and when transporting the recording sheet to the third sheet transport path FR3, an end portion of the flap39in the +Y direction is lifted upward (seeFIG. 3). By doing so, the recording sheet is transported to the third sheet transport path FR3and is transported to the reverse path RR. Further, the flap39is driven by a flap driving source (not illustrated) controlled by the controller (not illustrated).

A transport roller pair43is provided on the third sheet transport path FR3. The transport roller pair43includes a reverse driving roller44as a “third roller” that rotates and a reverse driven roller45that is driven to rotate. The reverse driving roller44is a rubber roller in the present embodiment, and the reverse driven roller45is a spur in point-contact with the recording sheet in the present embodiment.

From a viewpoint of applying a transport force to the recording sheet on the third sheet transport path FR3, the second discharge roller pair46functions as a first roller pair, and the transport roller pair43functions as a second roller pair.

The second discharge driving roller47included in the second discharge roller pair46can be driven in a normal rotation direction (clockwise direction inFIG. 2) to transport the recording sheet to the discharge port10through the first sheet transport path FR1in the first direction and can be driven in a reverse rotation direction (counterclockwise direction inFIG. 2) opposite to the normal rotation direction. The second discharge driven roller48included in the second discharge roller pair46nips the recording sheet with the second discharge driving roller47.

The second discharge roller pair46is positioned between the first sheet transport path FR1and the discharge port10, the recording sheet is discharged from the discharge port10by normal rotation of the second discharge driving roller47, and the recording sheet is transported to the third sheet transport path FR3by reverse rotation of the second discharge driving roller47.

The medium transport device4includes the plurality of sheet transport paths and the plurality of rollers described above. The medium transport device4can be considered a device with no function, such as a function of the recording head9, related to recording in the printer1.

In the medium transport device4including the above-described sheet transport paths, the feeding roller11and the reverse roller21are driven by a motor (not illustrated). Further, in the medium transport device4, the transport driving roller16, the first discharge driving roller41, the second discharge driving roller47, and the reverse driving roller44can be driven according to two embodiments: a first drive embodiment and a second drive embodiment.

In the first drive embodiment, the transport driving roller16, the first discharge driving roller41, the second discharge driving roller47, and the reverse driving roller44are driven by a first motor55(see FIG.5).

In the second drive embodiment, the transport driving roller16and the first discharge driving roller41are driven by the first motor55(seeFIG. 7), and the second discharge driving roller47and the reverse driving roller44are driven by a second motor56(seeFIG. 7). That is, the number of motors to be used differs between the first drive embodiment and the second drive embodiment.

For example, when a throughput-focused model is manufactured, the second drive embodiment of the medium transport device4is used and, when a cost-focused model is manufactured, the first drive embodiment of the medium transport device4is used, although the throughput-focused model and the cost-focused model have the same basic specification. As will be described in detail later, the printer1is configured so that the first and second drive embodiments can be implemented with the same frame configuration and little difference in components.

Next, the configuration of the medium transport device4will further be described with reference toFIGS. 5 to 9.FIGS. 5 and 8illustrate a configuration when the first drive embodiment is applied in the medium transport device, andFIGS. 6, 7, and 9illustrate a configuration when the second drive embodiment is applied. A medium transport device4A is a medium transport device according to the first drive embodiment, and a medium transport device4B is a medium transport device according to the second drive embodiment. However, when there is no need to distinguish the medium transport device4A according to the first drive embodiment and the medium transport device4B according to the second drive embodiment, both will be simply referred to as the medium transport device4.

The medium transport device4includes a side frame53provided on a side of the medium transport device4in the +X direction, and components such as a motor or a gear is attached to the side frame53. Further, the medium transport device4further includes a side frame (not illustrated) provided on a side of the medium transport device4in the −X direction, and a rotation shaft of a roller is supported by the side frame and the side frame53as necessary.

InFIG. 5, the first motor55is provided on the side frame53, and in the medium transport device4, rotational torque is transmitted from the first motor55to the transport driving roller16(seeFIG. 2) and the first discharge driving roller41(seeFIG. 2) through a second belt64according to both of the first drive embodiment and the second drive embodiment. InFIG. 5, a fourth pulley60is provided on a shaft end of the transport driving roller16, and a fifth pulley61is provided on a shaft end of the rotation shaft41aof the first discharge driving roller41. Further, a third pulley59applies tension to the second belt64.

InFIG. 5, a rotation shaft44ais provided, and a gear74is a gear as a “first rotor” and a “third roller driving gear”. The gear74is a gear that rotates around the rotation shaft44a. Rotational torque is transmitted from the gear74to a gear80through a one-way clutch75. The gear80meshes with a gear81, and the gear81meshes with a gear82. The gear82is provided on a shaft end of a rotation shaft83. The rotation shaft83is a rotation shaft of the reverse driving roller44(seeFIG. 2). That is, rotational torque is transmitted from the gear74to the reverse driving roller44through the one-way clutch75.

The one-way clutch75is a clutch for transmitting rotational torque in a certain direction to the gear80, regardless of the rotation direction of the gear74. Therefore, the reverse driving roller44(seeFIG. 2) always rotates in a rotation direction (counterclockwise direction inFIG. 2) to transport the recording sheet in the −Y direction.

On the other hand, the transport driving roller16and the first discharge driving roller41rotate in a rotation direction (clockwise direction inFIG. 2) to transport the recording sheet in the +Y direction by normal rotation of the first motor55, and rotate in a rotation direction (counterclockwise direction inFIG. 2) to transport the recording sheet in the −Y direction by reverse rotation of the first motor55.

A rotation shaft47ais a rotation shaft of the second discharge driving roller47(seeFIG. 2), and a second pulley58as a “second rotor” is provided on a shaft end of the rotation shaft47a. A first belt63is wound on the second pulley58, and the second discharge driving roller47is driven by the first belt63. Further, a driving source of the first belt63to be described later differs between the first drive embodiment and the second drive embodiment.

A driven pulley67is a driven pulley as a “tension applying member”, and the driven pulley67is supported by a slider66. The slider66is provided so as to be displaceable in a direction intersecting a direction in which the first belt63extends and is pressed by a tension spring68as a pressing member in a direction to push the driven pulley67against the first belt63. In this way, tension is applied to the first belt63.

Next, a characteristic configuration of the first drive embodiment will be described. As illustrated inFIG. 5, a rotor70as a “third rotor” is provided on the rotation shaft41aof the first discharge driving roller41. In the first drive embodiment, the rotation shaft41afunctions as a first shaft to which the rotor70is attached. Further, the shaft end of the rotation shaft41ais supported by a supporting frame77(seeFIG. 6). InFIG. 5, the supporting frame77is not illustrated. Further, a recess portion53bfor the rotation shaft41ato pass through in the X-axis direction is formed in the side frame53. In the present embodiment, the recess portion53bdoes not function as a bearing that holds the rotation shaft41a. However, the recess portion53bmay be configured to function as a bearing.

The rotor70provided on the rotation shaft41ais formed by integrating a first pulley57and a gear71as a “first gear” with each other. The gear71meshes with the gear74. Therefore, rotational torque of the motor55is transmitted from the rotation shaft41ato the gear74, and the reverse driving roller44(seeFIG. 2) rotates.

The above-described first belt63is wound on the first pulley57, and the rotational torque of the motor55is transmitted to the second discharge driving roller47through the first belt63. Further, in the first drive embodiment, the slider66supporting the driven pulley67that applies tension to the first belt63is guided by a first guide groove53h(seeFIG. 6) formed in the side frame53and is displaced in the direction intersecting the direction in which the first belt63extends. In the first drive embodiment, the tension spring68is hooked to a first spring hook portion53gformed on the side frame53and to the slider66.

In this way, in the first drive embodiment, the transport driving roller16is driven by the first motor55, the second discharge driving roller47and the reverse driving roller44are driven by the first motor55through the rotation shaft41aof the first discharge driving roller41and the gear71. As a result, it is possible to reduce parts costs of the apparatus.

Next, a characteristic configuration of the second drive embodiment will be described. As illustrated inFIGS. 6 and 7, in the second drive embodiment, the rotor70constituted by the first pulley57and the gear71described above is attached to a shaft portion53aas a second shaft, unlike the first drive embodiment described above. In the present embodiment, the shaft portion53ais integrated with the side frame53by using a resin material.

Further, fixing portions53dand53e(seeFIG. 5) are integrated with the side frame53, and a motor fixing plate76is fixed to the fixing portions53dand53eby using screws as illustrated inFIG. 6. Further,FIG. 7is a view illustrating a state in which the motor fixing plate76is removed in the state illustrated inFIG. 6.

The second motor56is fixed to the motor fixing plate76. The second motor56transmits rotational torque to the gear71through a gear76(seeFIG. 7). Further, the gear71meshes with the gear74. Accordingly, the rotational torque of the second motor56is transmitted to the reverse driving roller44(FIG. 2). The gear76is supported by a shaft portion53c(seeFIG. 5) integrated with the side frame53.

When the motor fixing plate76is fixed to the side frame53, a shaft end of the shaft portion53ais inserted into a hole of the motor fixing plate76as illustrated inFIG. 6, and is supported by the motor fixing plate76. As a result, displacement of the shaft portion53ais suppressed.

Further, a positioning shaft53fis formed on the side frame53(seeFIG. 5). When the motor fixing plate76is fixed to the side frame53, the positioning shaft53fis inserted into a hole of the side frame53(seeFIG. 6) to restrict a position of the side frame53.

Further, in the second drive embodiment, unlike the first drive embodiment described above, the slider66supporting the driven pulley67is guided by a second guide groove53k(seeFIG. 5) formed in the side frame53and is displaced in a direction intersecting a direction in which the first belt63extends. In addition, the tension spring68is hooked between a second spring hook portion53jformed on the side frame53, and the slider66, and is pressed in a direction to push the driven pulley67against the first belt63.

In this way, in the second drive embodiment, the transport driving roller16and the first discharge driving roller41are driven by the first motor55, and the second discharge driving roller47and the reverse driving roller44are driven by the second motor56through the gear71. As a result, a degree of freedom in control is increased.

For example, inFIGS. 3 and 4, a line with alternating long and short dashes P1indicates a preceding sheet transported to the third transport path FR3to perform recording on a second surface after recording is performed on a first surface. Further, a line with alternating long and two short dashes P2indicates a following sheet that is fed subsequent to the preceding sheet P1and is currently subjected to recording.

In a state illustrated inFIG. 3, the second discharge driving roller47rotates in a counterclockwise direction inFIG. 3by reverse rotation of the second motor56(seeFIG. 7) so as to transport the preceding sheet P1to the third transport path FR3.

However, when sheet transportation proceeds in this state, a leading edge of the following sheet P2reaches the second discharge driving roller47, and thus the second motor56is switched from the reverse rotation to normal rotation. As a result, the second discharge driving roller47rotates in a clockwise direction as illustrated inFIG. 4.

By applying the second drive embodiment as described above, it is possible to simultaneously perform the operation of transporting the preceding sheet P1in the third transport path FR3and the operation of performing recording on the following sheet P2. In other words, a degree of freedom in control is increased.

As described above, the rotor70is attached to the rotation shaft41aas the first shaft in the first drive embodiment, and is attached to the shaft portion53aas the second shaft in the second drive embodiment. That is, a driving force transmission configuration can vary between when using the rotation shaft41aand when using the shaft portion53a.

Further, as illustrated inFIGS. 8 and 9, a shaft center of the rotation shaft41aand a shaft center of the shaft portion53aare positioned on a circular arc Ra, the center of which is a rotation center of the second discharge driving roller47as the second roller. As a result, a distance between the rotation center of the second discharge driving roller47and the rotation shaft41a, and a distance between the rotation center of the second discharge driving roller47and the shaft portion53aare kept constant. In addition, both an interval between the rotation shaft41aand the gear74and an interval between the shaft portion53aand the gear74are set to a first interval.

Accordingly, the same specification of the rotor70and the first belt63can be used in both when transmitting a driving force between the gear74and the second discharge driving roller47by using the rotation shaft41a, that is, when applying the first drive embodiment, and when transmitting a driving force between the gear74and the second discharge driving roller47by using the shaft portion53a, that is, when applying the second drive embodiment. As a result, the same component configuration for the driving force transmission mechanism using a belt, a gear, or the like can be used in the first drive embodiment and the second drive embodiment, such that it is possible to effectively suppress an increase in costs when developing models with different specifications.

Further, in the medium transport device4, the first guide groove53h(seeFIG. 9) that guides the slider66, and the second guide groove53k(seeFIG. 8) that extends in a direction intersecting a direction in which the first guide groove53hextends and that guides the slider66are provided in the side frame53.

Therefore, it is possible to apply tension to the first belt63in an appropriate direction even when the same side frame53is used in the first drive embodiment and the second drive embodiment.

Further, in the present embodiment, the shaft portion53aas the second shaft is integrated with the side frame53. Therefore, it is possible to reduce costs of the apparatus. Further, in the present embodiment, the rotation shaft41aas the first shaft is a member separate from the side frame53. However, a shaft portion similar to the shaft portion53amay be integrated with the side frame53to function as the first shaft. In addition, in the present embodiment, the shaft portion53aas the second shaft is integrated with the side frame53. However, the shaft portion53amay be configured as a member separate from the side frame53.

It goes without saying that the present disclosure is not limited to the embodiments described above, that a variety of modifications is possible within the scope of the present disclosure described in the claims, and that the modifications also fall within the scope of the present disclosure.

For example, in the above-described embodiment, transmitting of a driving force using a gear may be replaced with transmitting of a driving force using a pulley and a belt, and it is a matter of course that transmitting of a driving force using a pulley and a belt may be replaced with transmitting of a driving force using a gear.