JP2013203502A - Image recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device capable of confirming switching of a gear, without adding an exclusive sensor.SOLUTION: A device includes a second sensor 120 detecting a recording paper sheet 12 to be conveyed and a third conveyance roller 45 located on the downstream side of the second sensor 120 and drive-transmitted from a movable first gear 51. The third conveyance roller 45 can be rotated only forward when the first gear 51 is in a second position and can be rotated forward and backward when the first gear 51 is engaged with a third gear 53 in a third position. The first gear 51 is moved to the third position and rotated forward and backward by a predetermined times. When the first gear 51 is not engaged with the third gear 53, the recording paper sheet 12 is only conveyed in a conveyance direction, whenever the first gear 51 is rotated forward (Fig. 9 (A) → (C)). From the time when both gears 51 and 53 are engaged with each other, the recording paper sheet 12 is conveyed in a direction opposite to the conveyance direction, whenever the first gear 51 is rotated backward (Fig. 9 (C) → (D)). A difference in the position of the recording paper sheet 12 based on presence/no presence of the engagement of both gears 51 and 53 is detected by the second sensor 120.

Description

  The present invention relates to an image recording apparatus capable of conveying a sheet along a conveyance path and recording an image on the sheet.

  Conventionally, an image recording apparatus that records an image on a sheet based on an input signal is known. As an image recording method of such an image recording apparatus, for example, there are an ink jet recording method and an electrophotographic method.

  In view of recent demands for miniaturization and cost reduction of image recording apparatuses, it is preferable that the number of motors mounted on the image recording apparatus is small. For example, in the image recording apparatus disclosed in Patent Document 1, a switching gear that is slidable in the thrust direction of the driving gear while meshing with a driving gear that is driven and transmitted from a driving source is disposed, and each sliding position of the switching gear is set. Corresponding to the above, a plurality of transmission gears for transmitting the drive to each mechanism are arranged. The switching gear is engaged with each transmission gear by sliding. By adopting the drive transmission switching mechanism having the above configuration, the number of drive sources mounted on the image recording apparatus can be reduced.

  The drive transmission switching mechanism as described above can be employed in an image recording apparatus capable of recording images on both sides of a sheet. This will be described in detail below. In the image recording apparatus, a refeed conveyance path is formed in addition to a main conveyance path that conveys a sheet from a paper feed tray to a discharge port through a recording unit that records an image on the sheet. The re-feed conveyance path is a conveyance path that conveys the sheet whose surface has been recorded by the recording unit and conveyed to the downstream side of the recording unit to the upstream side of the recording unit in the main conveyance path again. In the image recording apparatus, a transport roller is provided on the downstream side of the connection position between the main transport path and the refeed transport path on the downstream side of the recording unit. The conveyance roller discharges the sheet to the discharge port by normal rotation and guides the sheet to the re-feed conveyance path by reverse rotation.

  The conveying roller as described above is reversed by the reverse driving force from the driving source when the sheet is guided to the re-feed conveying path, but must be stopped even if the reverse driving force is transmitted from the driving source. There is a case. For example, in the image recording apparatus, it is necessary to transmit the reverse driving force to a mechanism other than the conveyance roller and it is not necessary to guide the sheet to the re-feed conveyance path. In such a case, if the conveyance roller to which the reverse driving force is transmitted reversely rotates, the sheet is fed back along the main conveyance path toward the refeed conveyance path. As a result, the sheet may be jammed in the apparatus.

  In order to prevent such a problem, the drive transmission switching mechanism as described above performs the first switching in which the sheet is conveyed forward to the discharge port and stopped by the reverse rotation, and the sheet is forwarded to the discharge port. It may be configured to selectively switch between the second switching for conveying and reversing and conveying the sheet in the direction opposite to the normal rotation and guiding the sheet to the re-feed conveyance path.

JP 2008-162736 A

  By the way, in the drive transmission switching mechanism as described above that switches the transmission gear meshed by sliding the switching gear in the thrust direction, the switching gear is switched when meshed with the transmission gear that has not been meshed until then. The gear needs to repeatedly execute forward and reverse rotations of a small amount of rotation. This is because the meshing of the switching gear with the newly meshed transmission gear is smoothly performed.

  However, it is not possible to obtain a guarantee that the meshing is surely performed by the forward / reverse rotation only by executing the forward / reverse rotation. Therefore, in the conventional image recording apparatus that employs the drive transmission switching mechanism as described above, the number of forward and reverse rotations where the meshing is surely performed is derived by an empirical rule by experiment or the like, Forward / reverse was executed.

  However, extra time is consumed by performing the forward / reverse rotation many times for gear switching. As a result, in the image recording apparatus, the time required for a series of image recording processes from the start of sheet conveyance to image discharge on the sheet through discharge of the sheet to the discharge outlet increases.

  There is also a means in which a dedicated sensor for detecting whether or not the gears can be switched is provided in the image recording apparatus. However, when such a means is employed, the cost of the image recording apparatus increases.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a means capable of confirming gear switching without adding a dedicated sensor.

  An image recording apparatus according to the present invention is provided with a recording unit that records an image on a sheet conveyed in a first direction on a first conveyance path, and an upstream side in the first direction from the recording unit. A first detection unit for detecting a sheet conveyed on one conveyance path; and a conveyance roller provided on the downstream side in the first direction with respect to the recording unit, wherein the sheet is rotated by rotating in the first rotation direction. The sheet is conveyed in the first direction and rotated in a second rotation direction opposite to the first rotation direction, thereby conveying the sheet in a second direction opposite to the first direction, thereby conveying the sheet to the conveyance roller and the above A transport roller for transporting along a second transport path connected to the first transport path at a first position between the recording sections; and between the recording section and the first position; 2nd detection which detects the sheet conveyed by 1 conveyance path A drive source that applies a driving force to the transport roller by being driven forward and reversely, and a forward drive of the drive source is transmitted to the transport roller so that the transport roller is oriented in the first rotation direction. A first switch that rotates and does not transmit the reverse drive of the drive source to the transport roller, and a forward drive of the drive source is transmitted to the transport roller to rotate the transport roller in the first rotation direction. And a drive transmission switching mechanism for selectively switching the second switching for transmitting the reverse drive of the drive source to the transport roller and rotating the transport roller in the second rotation direction, and the drive source and the drive transmission switch. A control unit for controlling the mechanism. The drive transmission switching mechanism is rotated by a driving force from the drive source and rotates to the second position and the third position, and the second gear meshes with the first gear at the second position. A gear, a third gear that meshes with the first gear in the third position, a first transmission unit that transmits the rotational driving force of the second gear to the conveying roller according to the transmission of the first switching, and the first gear A second transmission unit that transmits the rotational driving force of three gears to the transport roller according to the transmission of the second switching. The control unit is smaller than a conveyance amount in which a sheet is conveyed by performing normal rotation driving at a first rotation amount of one rotation or less by the drive source based on a detection signal of the first detection unit. Further, when the forward rotation driving is performed n-1 times, the sheet is moved to the fourth position on the upstream side in the first direction from the second detection unit by a set conveyance amount larger than the conveyance amount by which the sheet is conveyed. The first gear is moved from the second position to the third position on the condition that the seat is stopped and the execution of the stopping means is completed so that the rear end in the first direction is located. The first driving means for alternately executing the forward rotation driving and the reverse rotation driving of the first rotation amount of the driving source alternately n−1 times, and on the condition that the execution of the first driving means is completed. The drive source is driven forward by the first rotation amount. The first rotation of the drive source on the condition that the second detection unit is in a state in which the second detection unit does not detect the sheet after the second drive unit and the second drive unit perform the forward rotation drive of the drive source. The third drive means that reversely drives the motor by the amount, and the second drive section is in a state in which the second detector detects the sheet after completion of the reverse drive of the drive source by the third drive means. First conveying means for driving the sheet to roll and convey the sheet in the first direction.

  In the present invention, it is possible to accurately determine whether or not the moved first gear is meshed with the third gear, that is, gear switching. In the present invention, since the determination is made based on the detection result of the second detection unit for detecting the sheet, it is not necessary to add a dedicated sensor for determining whether or not the gear is switched to the apparatus.

FIG. 1 is a perspective view of the multifunction machine 10. FIG. 2 is a longitudinal sectional view schematically showing the internal structure of the printer unit 11. FIG. 3A is a plan view schematically showing meshing of the respective gears 51, 52, 53, 88 when the first gear 53 is in the third position, and FIG. FIG. 3C is a plan view schematically showing meshing of the gears 51, 52, 53, and 88 when is in the second position, and FIG. 3C is a right side view schematically showing the planetary gear 96. FIG. 4 is a perspective view schematically showing the drive transmission switching mechanism 50 and the transport rollers 60, 62, 45. FIG. 5 is a perspective view schematically showing the drive transmission switching mechanism 50 and the transport rollers 60, 62, 45. FIG. 6 is a block diagram illustrating a configuration of the control unit 130. FIG. 7A shows a table for explaining the rotation direction of each of the transport rollers 60, 62, 45 with respect to the position of the first gear 51, and FIG. A data table is shown, and FIG. 7C shows an actual result data table in an initial state. FIG. 8 is a flowchart for explaining control of detection of gear switching. FIG. 9 is a side view schematically showing the positional relationship between the second sensor 120 and the recording paper 12. FIG. 10 is a flowchart for explaining control of detection of gear switching in the modification.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings as appropriate. The embodiment described below is merely an example of the present invention, and it is needless to say that the embodiment of the present invention can be changed as appropriate without departing from the gist of the present invention. Further, in the following description, the progress from the starting point of the arrow to the ending point is expressed as “direction”, and the traffic on the line connecting the starting point and the ending point of the arrow is expressed as “direction”. Further, in the following description, the vertical direction 7 is defined with reference to a state in which the multifunction machine 10 is installed so as to be usable (the state in FIG. 1), and the side in which the opening 13 is formed is the front side (front side). 8 is defined, and the left-right direction 9 is defined when the multifunction machine 10 is viewed from the front side.

[Overall structure of MFP 10]
As shown in FIG. 1, the multifunction machine 10 (an example of the image recording apparatus of the present invention) includes a printer unit 11 at the bottom. The multifunction machine 10 has various functions such as a facsimile function and a print function. As a print function, it has a double-sided image recording function for recording images on both sides of the recording paper 12 (an example of the sheet of the present invention, see FIG. 2). The printer unit 11 has an opening 13 formed in the front. A paper feed tray 20 and a paper discharge tray 21 (see FIG. 2) on which the recording paper 12 can be placed can be inserted and removed in the front-rear direction 8 from the opening 13.

  As shown in FIG. 2, a paper feed roller 25 is provided above the paper feed tray 20. The sheet feeding roller 25 is rotated by driving transmission from a sheet feeding motor 70 (see FIG. 6). As a result, the recording paper 12 placed on the paper feed tray 20 is fed to the first transport path 65.

  A first transport path 65 extends from the rear end of the paper feed tray 20. The 1st conveyance path 65 is comprised by a curved part and a linear part. The first transport path 65 is partitioned by an outer guide member 18 and an inner guide member 19 that face each other with a predetermined interval. The recording paper 12 accommodated in the paper feed tray 20 is conveyed so as to make a U-turn from the lower side to the upper side of the curved portion, and then conveyed along the straight portion to the recording unit 24. The recording paper 12 on which image recording has been performed by the recording unit 24 is conveyed through the linear portion and discharged to the paper discharge tray 21. That is, the recording paper 12 is conveyed in the first direction 15 indicated by the one-dot chain line arrow in FIG.

  The first conveyance path 65 is provided with a roller pair including a first conveyance roller 60 and a pinch roller 61 on the upstream side in the first direction 15 from the recording unit 24, and downstream in the first direction 15 from the recording unit 24. A pair of rollers including the second transport roller 62 and the spur 63 is provided, and the third transport roller 45 (an example of the transport roller of the present invention) and the spur 46 are disposed downstream of the second transport roller 62 in the first direction 15. A pair of rollers is provided. Each roller pair sandwiches and conveys the recording paper 12.

  Each of the transport rollers 60, 62, 45 is given a driving force from a transport motor 71 (an example of a drive source of the present invention, see FIG. 6) via a drive transmission switching mechanism 50 (see FIGS. 4 and 5) described later. Has been rotated. The conveyance motor 71 is driven forward and backward. Each of the transport rollers 60, 62, and 45 to which the driving force is applied from the transport motor 71 that is normally rotated rotates in the first rotation direction. Here, the first rotation direction is a rotation direction in which the recording paper 12 is conveyed in the first direction 15. Each of the transport rollers 60, 62, 45 to which the driving force is applied from the transport motor 71 driven in the reverse direction rotates in the second rotation direction. Here, the second rotation direction is a rotation direction in which the recording paper 12 is conveyed in a second direction opposite to the first direction 15.

  A first position 36 exists between the second conveyance roller 62 and the third conveyance roller 45 in the first conveyance path 65. During double-sided image recording, the recording paper 12 conveyed through the first conveyance path 65 is switched back downstream of the first position 36 and conveyed toward a second conveyance path 67 described later.

  A recording unit 24 is provided above the first conveyance path 65. A platen 42 is provided below the recording unit 24 and at a position facing the recording unit 24. The platen 42 is a plate-like member and supports the recording paper 12 that is transported through the first transport path 65. The recording unit 24 records an image on the recording paper 12 supported by the platen 42 by a known ink jet method, and includes a recording head 38 having a plurality of nozzles for ejecting ink droplets on the recording paper 12, and a recording head. And a carriage 40 on which the head 38 is mounted. The carriage 38 is supported by the frame of the printer unit 11 so as to be reciprocable in the left-right direction 9. The carriage 38 is connected to a carriage drive motor 103 (see FIG. 6) via a known belt mechanism, and is reciprocated in the left-right direction 9 by being transmitted from the carriage drive motor 103. The recording unit 24 may record an image on the recording paper 12 by, for example, an electrophotographic method other than the ink jet method.

[First sensor 110 and second sensor 120]
As shown in FIG. 2, a first sensor 110 is provided on the upstream side of the first direction 15 relative to the first conveyance roller 60 in the first conveyance path 65. The first sensor 120 includes a shaft 111, a detector 112 that can rotate around the shaft 111, and an optical sensor 113 that includes a light emitting element and a light receiving element that receives light emitted from the light emitting element. Yes.

  One end of the detector 112 protrudes into the first transport path 65. When an external force is not applied to one end of the detector 112, the other end of the detector 112 enters the optical path from the light emitting element to the light receiving element of the optical sensor 113, and blocks light passing through the optical path. At this time, a low level signal is output from the optical sensor 113 to the control unit 130 described later. When one end of the detector 112 is pushed by the leading end of the recording paper 12 and rotates, the other end of the detector 112 is removed from the optical path, and light passes through the optical path. At this time, a high level signal is output from the optical sensor 113 to the control unit 130. Based on the signal from the optical sensor 113, the control unit 130 detects the leading edge and the trailing edge of the recording paper 12 in the first direction 15. The first sensor 110 and the control unit 130 are an example of a first detection unit of the present invention.

  A second sensor 120 is provided between the second conveyance roller 62 and the first position 36 in the first conveyance path 65. The second sensor 120 is configured in the same manner as the first sensor 110 and includes a shaft 121, a detector 122, and an optical sensor 123. The second sensor 120 operates in the same manner as the first sensor 110 and detects the leading edge and the trailing edge of the recording paper 12 conveyed through the first conveying path 65. The second sensor 120 and the control unit 130 are an example of a second detection unit of the present invention.

[Rotary encoder 73]
As shown in FIG. 2, the first transport roller 60 is provided with a rotary encoder 73 that detects the amount of rotation of each of the transport rollers 60, 62, 45. The rotary encoder 73 includes an encoder disk 74 provided on the shaft 35 of the first transport roller 60 and rotating together with the first transport roller 60 and an optical sensor 75. The encoder disk 74 is formed with a pattern in which light transmitting parts and light non-transmitting parts are alternately arranged at equal pitches in the circumferential direction. When the encoder disk 74 rotates, a pulse signal is generated each time the optical sensor 75 detects a transmissive part and a non-transmissive part. The generated pulse signal is output to the control unit 130. The controller 130 calculates the rotation amount of the first transport roller 60 based on the pulse signal. As will be described later, the transport rollers 60, 62, and 45 are connected by a belt. Therefore, the control unit 130 can also calculate the rotation amounts of the second conveyance roller 62 and the third conveyance roller 45 based on the pulse signal. The rotary encoder 73 and the control unit 130 are an example of a rotation amount detection unit of the present invention.

[Route switching unit 41 and second conveyance path 67]
As shown in FIG. 2, the path switching unit 41 is provided between the second conveyance roller 62 and the third conveyance roller 45 in the first conveyance path 65. The path switching unit 41 includes auxiliary rollers 47 and 48, a flap 49, and a shaft 87. The flap 49 extends substantially in the first direction 15 from the shaft 87 and is pivotally supported by the shaft 87 so as to be rotatable. Spur-shaped auxiliary rollers 47 and 48 are pivotally supported on the flap 49.

  The flap 49 has a discharge position (position indicated by a broken line in FIG. 2) positioned above the inner guide member 19, and a reverse position (in FIG. 2) in which the extended end portion 49A enters below the first position 36. (Posture indicated by a solid line). The flap 49 is in a reverse posture due to its own weight in a normal state, but when the flap 49 is lifted by the recording paper 12 conveyed through the first conveyance path 65, the flap 49 rotates to a discharge posture. When the rear end of the recording paper 12 passes through the auxiliary roller 47, the flap 49 is rotated from the discharge posture to the reverse posture by its own weight. In this state, when the forward rotation of the third transport roller 45 is continued, the recording paper 12 is transported in the first direction 15 and discharged onto the paper discharge tray 21. On the other hand, when the rotation direction of the third conveyance roller 45 is switched from normal rotation to reverse rotation, the recording paper 12 is conveyed in the second direction and guided to the second conveyance path 67.

  The second conveyance path 67 is branched from the first conveyance path 65 at the first position 36, and merges with the first conveyance path 65 at the merge position 37 upstream of the first conveyance roller 65 in the first direction 15. It is an extended path. The second transport path 67 is partitioned by the guide members 31 and 32.

[Drive transmission switching mechanism 50]
As shown in FIGS. 4 and 5, the printer unit 11 is provided with a drive transmission switching mechanism 50. The drive transmission switching mechanism 50 selectively switches the transmission of the driving force of the conveyance motor 71 between the first switching and the second switching, as will be described below. The drive transmission switching mechanism 50 includes a first gear 51, a second gear 52, a third gear 53, a first transmission unit 54, and a second transmission unit 57.

  The first pulley 76 is attached to the shaft 34 of the first transport roller 60 on the left side of the first transport path 65. A motor pulley 58 (see FIG. 4) is attached to the shaft (not shown) of the conveyance motor 71. An endless annular first belt 77 is stretched between the first pulley 76 and the motor pulley 58. Thereby, the rotational driving force of the conveyance motor 71 is transmitted to the first conveyance roller 60.

  A second gear 52 is provided on the shaft 34 of the first transport roller 60. In the present embodiment, the second gear 52 includes a right gear 78 provided on the right side of the first transport path 65 and a left gear 79 provided on the left side of the first transport path 65.

  The first gear 51 is meshed with the right gear 78. As a result, the first gear 51 rotates with the driving force applied from the transport motor 71. Further, as shown in FIGS. 3A and 3B, the first gear 51 is moved to the third position (FIG. 3A) along the left-right direction 9 while maintaining meshing with the right gear 78. It is possible to move to a position shown) and a second position (position shown in FIG. 3B). A coil spring 56 is attached to the right surface of the first gear 51. The coil spring 56 is disposed along the axial direction of the first gear 51, one end is attached to the right surface of the first gear 51, and the other end is attached to a frame (not shown) of the printer unit 11. ing. Thereby, the first gear 51 is urged to the left side, that is, the third position side by the coil spring 56. As shown in FIGS. 4 and 5, a protrusion 55 is formed on the shaft of the first gear 51. The carriage 55 of the recording unit 24 can come into contact with the protrusion 55 from the left side.

  Therefore, when the carriage 40 moves to the right side, the protrusion 55 is pushed by the carriage 40. As a result, the first gear 51 moves from the third position to the second position against the biasing force of the coil spring 56. The first gear 51 that has moved to the second position is prevented from moving from the second position to the third position by a stopper (not shown). Thereby, the first gear 51 can remain in the third position. If the projection 55 is pushed by the carriage 40 and moved further to the right side than the second position when the first gear 51 is positioned at the third position, the first gear 51 is released from being stopped by the stopper. . In this state, when the carriage 40 moves to the left side, the first gear 51 is moved from the second position to the third position by the biasing force of the coil spring 56.

  As shown in FIG. 3B, the first gear 51 in the second position is meshed with the first intermediate gear 88. At this time, the rotational driving force transmitted from the conveying motor 71 to the first gear 51 is the first intermediate gear 88 and the second intermediate gear 89 as shown in FIGS. 3B, 4 and 5. The fourth belt 90, the third intermediate gear 91, the fourth intermediate gear 92 attached to the shaft 93, the shaft 93, and the fifth belt 94 are transmitted to the paper feeding roller 25. Further, when the first gear 51 is located at the second position, the rotational driving force of the transport motor 71 causes the second transport roller 62 and the third transport roller 45 to pass through the first transmission portion 54 as will be described later. Is transmitted to.

  As shown in FIG. 3A, the first gear 51 in the third position is meshed with the third gear 53. At this time, the rotational driving force transmitted from the conveying motor 71 to the first gear 51 is transmitted to the second conveying roller 62 and the third conveying roller 45 via the second transmitting portion 57 as will be described later.

[First transmission unit 54]
As shown in FIGS. 3B, 4, and 5, the first transmission unit 54 includes a pinch roller gear 80, a second pulley 81, a third pulley 82, a fourth pulley 84, a fifth pulley 85, A second belt 83 and a third belt 86 are included.

  The pinch roller gear 80 is attached to the shaft 35 (see FIG. 2) of the pinch roller 61 and meshes with the left gear 79. The second pulley 81 is attached to the right side of the pinch roller gear 80 on the shaft 35. The third pulley 82 is attached to the shaft 64 of the second transport roller 60. An endless annular second belt 83 is stretched between the second pulley 81 and the third pulley 82. Thereby, the rotational driving force of the first transport roller 60 is transmitted to the second transport roller 62.

  The fourth pulley 84 is attached to the left side of the third pulley 82 on the shaft 64. The fifth pulley 85 is attached to the shaft 44 of the third transport roller 45. An endless annular third belt 86 is stretched around the fourth pulley 84 and the fifth pulley 85. Thereby, the rotational driving force of the second transport roller 62 is transmitted to the third transport roller 45.

  The third pulley 82 is attached to the shaft 64 via a known one-way clutch (not shown). Thereby, in this embodiment, the shaft 64 is normally rotated when the conveyance motor 71 is rotated forward, but is not rotated when the conveyance motor 71 is reversely rotated. As a result, when the conveyance motor 71 rotates in the forward direction, the forward rotation drive amount is transmitted to all the conveyance rollers 60, 62, and 45, and all the conveyance rollers 60, 62, and 45 rotate in the normal direction. On the other hand, when the conveyance motor 71 rotates in the reverse direction, the reverse rotation amount is transmitted to the first conveyance roller 60. However, since the third pulley 82 rotates idly by the action of the one-way clutch, the second conveyance roller 62 and the third conveyance roller The reverse rotation drive amount is not transmitted to the roller 45. As a result, only the first conveyance roller 60 is reversed, and the second conveyance roller 62 and the third conveyance roller 45 are not reversed.

  The rotation of the transport rollers 60, 62, 45 with respect to the forward / reverse rotation of the transport motor 71 as described above is realized when the first gear 51 is located at the second position (the position shown in FIG. 3B). (See the first and second columns in FIG. 7A). That is, when the first gear 51 is located at the second position, the drive transmission switching mechanism is switched to the first switching. As described above, the first transmission unit 54 transmits the rotational driving force of the second gear 52 to the third transport roller 45 according to the transmission of the first switching.

[Second transmission unit 57]
As shown in FIGS. 3A, 4, and 5, the second transmission portion 57 includes a plurality of fifth intermediate gears 95, planetary gears 96, fourth pulleys 84, and third belts that are meshed with each other. 86 and a fifth pulley 85. As shown in FIG. 3C, the planetary gear 96 includes a sun gear 97 that meshes with the fifth intermediate gear 95, and a planet gear 98 that rotates while revolving around the sun gear 97.

  When the conveyance motor 71 rotates in the reverse direction, the planet gear 98 revolves around the sun gear 97 in the direction of the arrow 99. As a result, the planet gear 98 meshes with the second transport roller gear 101 provided at the right end of the shaft 64 of the second transport roller 62. As a result, the second transport roller 62 reverses (see the fourth row in FIG. 7A). Further, the reverse rotational driving force of the second transport roller 62 is transmitted to the third transport roller 45 via the fourth pulley 84, the third belt 86, and the fifth pulley 85. As a result, the third transport roller 45 reverses (see the fourth row in FIG. 7A). From the above, when the conveyance motor 71 is reversed, the conveyance rollers 60, 62, 45 are reversed.

  On the other hand, when the transport motor 71 rotates forward, the planet gear 98 revolves around the sun gear 97 in the direction of the arrow 100. Thereby, the planet gear 98 is separated from the second transport roller gear 101. At this time, as described above, the forward driving force of the conveyance motor 71 is transmitted to the second conveyance roller 62 and the third conveyance roller 45 by the first transmission unit 54. As a result, when the conveyance motor 71 rotates normally, the conveyance rollers 60, 62, and 45 rotate normally (see the third column in FIG. 7A).

  The rotation of the transport rollers 60, 62, 45 with respect to the forward / reverse rotation of the transport motor 71 as described above is realized when the first gear 51 is located at the third position (the position shown in FIG. 3A). (See the third and fourth columns in FIG. 7A). That is, when the first gear 51 is located at the third position, the drive transmission switching mechanism is switched to the second switching. From the above, the second transmission unit 57 transmits the rotational driving force of the third gear 53 to the third transport roller 45 according to the transmission of the second switching.

[Forward / reverse rotation at first rotation amount of gear performed for gear switching]
In the drive transmission switching mechanism 50 configured as described above, when the first gear 51 is disengaged from the first intermediate gear 88 and meshed with the third gear 53, or away from the third gear 53, the first intermediate gear 51 is engaged. When meshed with the gear 88, the positions of the teeth of the gears do not match, and therefore the first gear 51, the third gear 53, and the first intermediate gear 88 may not mesh well. That is, there is a possibility that the gear of the first gear 51 is not properly switched.

  Therefore, in the present embodiment, as will be described later, when the gear of the first gear 51 is switched (specifically, immediately after the first gear 51 moves between the second position and the third position), the control unit By 130, the forward rotation and the reverse rotation of the conveyance motor 71 are alternately executed at least once. At this time, each rotation amount of the forward rotation and the reverse rotation of the conveyance motor 71 is a first rotation amount of one rotation or less of the conveyance motor 71. In the present embodiment, the first rotation amount is a rotation amount that is at least equal to or greater than the gap between the teeth of the first gear 51, the third gear 53, and the first intermediate gear 88.

  As described above, the forward rotation and the reverse rotation of the conveyance motor 71 are alternately performed at least once, whereby the first gear 51 is alternately rotated in the normal rotation and reverse rotation directions. As a result, the teeth of each gear are matched so that they can mesh with each other, and the switching of each gear is performed smoothly and reliably.

[Control unit 130]
The control unit 130 controls the overall operation of the multifunction machine 10. For example, the control unit 130 controls driving of the paper feed motor 70 and the transport motor 71. Further, the control unit 130 controls the drive transmission switching mechanism 50 by controlling the movement of the carriage 40. The control unit 130 includes a CPU 131, a ROM 132, a RAM 133, an EEPROM 134, an ASIC 135, and an internal bus 137 that connects these components to each other.

  The ROM 132 stores a program for the CPU 131 to control various operations. The RAM 133 is used as a storage area for temporarily recording data, signals, and the like used when the CPU 131 executes the program. The EEPROM 134 stores settings, flags, and the like that should be retained even after the power is turned off.

  Connected to the ASIC 135 are a paper feed motor 70, a transport motor 71, and a carriage drive motor 103. When a drive signal for rotating each motor is input from the CPU 131 to a drive circuit corresponding to a predetermined motor, a drive current corresponding to the drive signal is output from the drive circuit to the corresponding motor, thereby corresponding The motor rotates forward or reverse at a predetermined rotational speed.

  The ASIC 135 receives a pulse signal output from the optical sensor 75 of the rotary encoder 73. The control unit 130 calculates the rotation amount of each of the transport rollers 60, 62, 45 based on the pulse signal from the optical sensor 75.

  The ASIC 135 is connected to the optical sensor 113 of the first sensor 110 and the optical sensor 123 of the second sensor 120. The control unit 130 detects the leading edge and the trailing edge of the recording paper 12 in the first direction 15 at the positions where the sensors 110 and 120 are arranged based on the signals from the optical sensors 113 and 123.

[Control by control unit 130]
Hereinafter, a procedure of processing when the control unit 130 detects whether or not there is gear switching accompanying the movement of the first gear 51 will be described based on the flowchart of FIG. 8. In the following description, the initial position of the first gear 51 is assumed to be the second position.

  When an instruction to record an image on the recording paper 12 is input to the multifunction machine 10 from the operation panel 17 (see FIG. 1) or the like, the control unit 130 drives the paper feeding motor 70. As a result, the paper feed roller 25 is rotated, the recording paper 12 is fed from the paper feed tray 20 to the first transport path 65, and transported in the first direction 15 through the first transport path 65. At this time, the control unit 130 reverses the conveyance motor 71. Thereby, the 1st conveyance roller 60 reversely rotates. In addition, since the 1st gear 51 is located in a 2nd position, the 2nd conveyance roller 62 and the 3rd conveyance roller 45 have stopped (refer the 2nd row | line | column of FIG. 7 (A)). When the leading edge 15 of the recording paper 12 in the first direction 15 reaches the first conveying roller 60, the skewing of the recording paper 12 is corrected by contacting the first conveying roller 60 that reverses the leading edge. Thereafter, the control unit 130 causes the transport motor 71 to rotate forward. As a result, the recording paper 12 is transported directly below the recording unit 24 by the first transport roller 60, and an image is recorded by the recording unit 24. The above process is step S10.

  The control unit 130 determines whether or not the result data table is in an initial state (S20). Here, as shown in FIG. 7B, the record data table is composed of n values used in the processing after step S50 and count values corresponding to the respective n values. . The value of n is the number of forward and reverse rotations of the first gear 51. The count value corresponding to the value of n is the number of times that the gear switching of the first gear 51 has been completed with the value of n in the image recording from the past to the present. Further, the fact data table is in an initial state is a state in which all count values are zero, as shown in FIG. 7C.

  In the present embodiment, the result data table is stored in the RAM 133. In this case, the RAM 133 is an example of the first storage unit of the present invention. Further, the result data table may be stored in the EEPROM 134. In this case, the EEPROM 134 is an example of the first storage unit of the present invention. When the actual result data table is stored in the EEPROM 134, the actual result data table is not erased even when the power of the multifunction machine 10 is turned off.

  When the result data table is in the initial state (S20: Yes), the value of n used in the processing after step S50 is set to “1” (S30). On the other hand, when the performance data table is not in the initial state (S20: No), the value of n used in the processing after step S50 is set to the value of n corresponding to the largest count value (S40). FIG. 7B shows an example in which the result data table is not in the initial state. In this example, the value of n is set to “4” in step S40. The value of n is used in the processing of steps S50 and S60 described later. The process of step S40 is an example of a first determination unit of the present invention.

  The control unit 130 detects the leading edge 15 in the first direction 15 of the recording paper 12 based on the signal from the optical sensor 113 of the first sensor 110 and each transport roller based on the pulse signal from the optical sensor 75 of the rotary encoder 73. Based on the rotation amounts 60 and 62, the position of the recording paper 12 is determined. Based on the determination, the control unit 130 stops the recording paper 12 so that the rear end of the recording paper 12 in the first direction 15 is located at the fourth position (S50). At this time, the recording paper 12 is sandwiched between the third transport roller 45 and the spur 46.

  Here, in the present embodiment, the fourth position P is a position upstream of the second sensor 120 in the first transport path 65 by the set transport amount SM, as shown in FIG. 9A. The set transport amount SM is smaller than the first transport amount M1 to which the recording paper 12 is transported when the forward rotation driving of the first rotation amount of the transport motor 71 is performed n times (four times in FIG. 9A). . The set transport amount SM is the second transport amount in which the recording paper 12 is transported by forward rotation of the first rotation amount of the transport motor 71 by n-1 (three times in FIG. 9A). Greater than M2. 9A is a unit transport amount M by which the recording paper 12 is transported when the forward rotation drive of the first rotation amount of the transport motor 71 is performed once. The process of step S50 is an example of a stopping unit of the present invention.

  After step S50, the control unit 130 moves the first gear 51 from the second position to the third position by moving the carriage 40 (S60). Thereafter, the control unit 130 causes the forward rotation and the reverse rotation at the first rotation amount of the transport motor 71 to be alternately executed n−1 times (S60). The process of step S60 is an example of the first drive unit of the present invention. For example, in the case of FIG. 9, the forward / reverse rotation of the transport motor 71 is executed three times.

  If the first gear 51 moved to the third position is not meshed with the third gear 53 even after n-1 forward and reverse rotations of the transport motor 71 in step S60, the third transport roller 45 is transported by the transport motor. The motor 71 is rotated forward by the forward rotation of 71 and stopped by the reverse rotation of the transport motor 71. Therefore, for example, in the case of FIG. 9, the recording paper 12 is transported in the first direction 15 by three times the unit transport amount M by the forward / reverse rotation of the transport motor 71 in step S60. As a result, the recording paper 12 is in the position shown in FIG.

  On the other hand, when the first gear 51 moved to the third position is engaged with the third gear 53 before the forward / reverse rotation of the conveyance motor 71 in step S60 is executed n-1 times, the first gear 51 is third. After meshing with the gear 53, the third transport roller 45 is rotated forward by the forward rotation of the transport motor 71 and reversed by the reverse rotation of the transport motor 71. As a result, for example, in the case of FIG. 9, the recording paper 12 is positioned upstream in the first direction 15 from the position shown in FIG.

  After execution of step S60, the control unit 130 causes the transport motor 71 to rotate forward once with the first rotation amount (S70). As a result, the recording paper 12 is transported in the first direction 15 by the unit transport amount M. The process of step S70 is an example of the second driving means of the present invention.

  After executing step S70, the control unit 130 determines whether or not the state of the second sensor 120 is ON (S80). When the position of the recording paper 12 at the end of step S60 is the position shown in FIG. 9B, the recording paper 12 is at the position shown in FIG. 9C at the end of step S70. That is, the rear end of the recording paper 12 passes through the second sensor 120. As a result, the second sensor 120 switches from OFF, which is a state of detecting the recording paper 12, to ON, which is a state of not detecting the recording paper 12 (S80: Yes). In this case, step S90 described below is executed.

  On the other hand, when the position of the recording paper 12 at the end of step S60 is upstream in the first direction 15 from the position shown in FIG. 9B, the recording paper 12 is transferred to the position shown in FIG. ) And a position on the upstream side in the first direction 15 from the position indicated by (). That is, the rear end of the recording paper 12 does not pass through the second sensor 120. Thereby, the 2nd sensor 120 maintains OFF (S80: No). In this case, step S140 described later is executed.

  When the second sensor 120 is switched from OFF to ON (S80: Yes), the control unit 130 reverses the conveyance motor 71 once by the first rotation amount (S90). The process of step S90 is an example of a third driving unit of the present invention.

  When the first gear 51 moved to the third position meshes with the third gear 53 by the forward rotation in step S70 or the reverse rotation in step S90, the third transport roller 45 is reversely rotated by the reverse rotation of the transport motor 71 ( (See the fourth column in FIG. 7A). As a result, for example, in the case of FIG. 9, the recording paper 12 is conveyed from the position shown in FIG. 9C to the position shown in FIG.

  On the other hand, if the first gear 51 that has moved to the third position is not meshed with the third gear 53 by the forward rotation in step S70 or the reverse rotation in step S90, the third transport roller 45 rotates the reverse of the transport motor 71. (See the second column in FIG. 7A). As a result, for example, in the case of FIG. 9, the recording paper 12 maintains the position shown in FIG. 9C by the reverse rotation in step S90.

  After step S90, the control unit 130 determines whether or not the state of the second sensor 120 is ON (S100). For example, when the position of the recording paper 12 at the end of step S90 is the position shown in FIG. 9E, the second sensor 120 is switched from ON to OFF (S100: No). That is, the recording paper 12 is detected by the second detection unit. In this case, step S110 described below is executed.

  On the other hand, when the position of the recording paper 12 at the end of step S90 is the position shown in FIG. 9C, the second sensor 120 maintains ON (S100: Yes). That is, the recording paper 12 is not detected by the second detection unit. In this case, step S160 described later is executed.

  When the second sensor 120 is switched from ON to OFF (S100: No). The control unit 130 increments the count value (13 in the present embodiment) corresponding to the current value of n (4 in FIG. 9) in the performance data table stored in the RAM 133 (S110). The processing in steps S100 and S110 is an example of the count value changing means of the present invention.

  Next, the control unit 130 causes the conveyance motor 71 to rotate forward. Thereby, the 3rd conveyance roller 45 is rotated forward. As a result, the recording paper 12 is conveyed in the first direction 15 to the switchback start position (S120). Here, the switchback start position is a position at which the recording paper 12 is transported toward the second transport path 67 when the third transport roller 45 is reversed. In the present embodiment, the recording paper 12 at the switchback start position has the rear end of the first direction 15 positioned at a first position 36 between the auxiliary roller 47 and the auxiliary roller 48. The processes of steps S100 and S120 are an example of the first transport unit of the present invention.

  When the recording paper 12 is conveyed to the switchback start position, the control unit 130 switches the conveyance motor 71 from normal rotation to reverse rotation. Thereby, the 3rd conveyance roller 45 is reversely rotated. As a result, the recording paper 12 is conveyed toward the second conveyance path 67 (S130). The process of step S130 is an example of the second transport unit of the present invention.

  When the second sensor 120 is kept OFF in step S80 (S80: No), the control unit 130 determines whether the value of n is larger than “1” (S140). When the value of n is larger than “1” (S140: Yes), the value of n is decreased by 1 (S150). Note that the number of decreases in the value of n is not limited to 1. The process of step S150 is an example of a reducing unit of the present invention. When the value of n is “1” or less (S140: No), the control unit 130 does not decrease the value of n. This is because when the reduction is executed, the value of n becomes zero or less.

  After executing the determination of the value of n (S140) and the decrease of the value of n (S150), the control unit 130 executes step S110. That is, the control unit 130 conveys the recording paper 12 in the first direction 15 on the condition that the second sensor 120 is OFF after step S70 (S80: No) (S120). The processing in steps S80 and S120 is also an example of the first transport unit of the present invention.

  In step S100, when the second sensor 120 is kept ON (S100: Yes), the control unit 130 increases the value of n by 1 (S160). Note that the number of increases in the value of n is not limited to 1. The process of step S160 is an example of the increasing means of the present invention.

  After execution of step S160, the control unit 130 executes step S170. That is, the control unit 130 sets the transport motor 71 at the first rotation amount on the condition that the second sensor 120 is kept ON after the execution of step S90 as the third driving unit (S100: Yes). Rotate forward once and then reverse once with the second rotation amount (S170). Here, the second rotation amount is a rotation amount larger than the first rotation amount. In the present embodiment, the second rotation amount is a rotation amount of one rotation or less of the conveyance motor 71. The process of step S170 is an example of a fourth drive unit of the present invention. As described later, step S170 can be executed a plurality of times.

  After executing step S170, the control unit 130 determines whether or not the state of the second sensor 120 is ON (S180).

  Since the second rotation amount is larger than the first rotation amount, if step S170 is executed in a state where the first gear 51 moved to the third position is engaged with the third gear 53, the recording paper 12 is rotated in the second rotation. Only the difference between the amount and the first rotation amount is conveyed in the second direction opposite to the first direction 15. When the recording paper 12 conveyed in the second direction reaches the second sensor 120, specifically, when the recording paper 12 changes from the state shown in FIG. 9C to the state shown in FIG. Is switched from ON to OFF (S180: No). In this case, the control part 130 performs the process after step S110. That is, the control unit 130 conveys the recording paper 12 in the first direction 15 on the condition that the state of the second sensor 120 is OFF (S180: No) after completion of the execution of step S170 as the fourth driving unit. (S120). The processing in steps S170, S180, and S120 is also an example of the first transport unit of the present invention.

  On the other hand, when the state of the second sensor 120 is maintained ON (S180: Yes), the control unit 130 determines whether or not the number of executions of step S170 is greater than the set number (S190). Here, the set number of times is a value set in advance and stored in the ROM 132, the EEPROM 134, or the RAM 133. For example, the number of executions of step S170 necessary for surely engaging the moved first gear 51 with the third gear 53 or the first intermediate gear 88 is derived by an empirical rule or the like. The derived number of executions is set as the set number. The process of step S190 is an example of a determination unit of the present invention.

  When the execution count is larger than the set count (S190: Yes), the control unit 130 switches the transport motor 71 to the reverse direction and transports the recording paper 12 in the second direction (S130). The processes in steps S190 and S130 are an example of the third transport unit of the present invention.

  When the number of executions is equal to or less than the set number (S190: No), the control unit 130 executes step S170, which is the fourth driving unit, again. In step S <b> 170, when the moved first gear 51 meshes with the third gear 53, the recording paper 12 is conveyed in the second direction and approaches the second sensor 120. As a result, after the execution of step S170 is completed, there is a high possibility that the state of the second sensor 120 is OFF.

[Effect of the embodiment]
In the present embodiment, switching from the first switching to the second switching in the drive transmission switching mechanism 50 is performed by moving the first gear 51 and newly meshing with the third gear 53. That is, switching from the first switching to the second switching in the drive transmission switching mechanism 50 is performed by gear switching.

  In the present embodiment, in step S50, the recording paper 12 is stopped upstream of the second sensor 120 in the first direction 15 by the set transport amount SM (see FIG. 9A). Next, in step S60, the control unit 130 moves the first gear 51 from the second position to the third position, and drives the transport motor 71 n-1 times forward and backward. Here, when the drive transmission switching mechanism 50 has not yet switched from the first switching to the second switching after the movement of the first gear 51, that is, when the gear switching has not been completed, n−1 of the transport motor 71. The sheet is transported by (n−1) × unit transport amount M by the forward rotation drive. Next, in step S <b> 70, the control unit 130 causes the conveyance motor 71 to perform normal rotation driving, that is, n-th normal rotation driving.

  In the present embodiment, in order to detect the recording paper 12 provided in the first conveyance path 65, whether or not the drive transmission switching mechanism 50 is switched from the first switching to the second switching by the n-th forward rotation driving. It can be determined by the detection result of the second sensor 120. This will be described in detail below.

  During the n-th forward rotation drive, the second sensor 120 transitions from a state in which the recording paper 12 is detected to a state in which it is not detected (see FIG. 9C). Next, in step S90, the control unit 130 drives the transport motor 71 in the reverse direction. Here, when the gear switching from the first switching to the second switching is performed at the n-th forward driving, the recording paper 12 is conveyed in the second direction by the reverse driving. Even when the gear switching from the first switching to the second switching is performed during the reverse rotation driving, the recording paper 12 can be conveyed in the second direction by the reverse driving. As a result, the second sensor 120 transitions from a state in which the recording paper 12 is not detected to a state in which it is detected (see FIG. 9B). On the other hand, if the gear switching from the first switching to the second switching is not performed during the n-th forward driving or the reverse driving, the recording paper 12 is not conveyed in the second direction by the reverse driving. As a result, the second sensor 120 maintains a state in which the recording paper 12 is not detected (see FIG. 9C). As described above, in the present embodiment, the control unit 130 performs the gear switching from the first switching to the second switching of the drive transmission switching mechanism 50 based on the detection result based on the signal from the second sensor 120 after the reverse driving. Presence / absence can be accurately determined.

  Here, the second sensor 120 is necessary for detecting the timing of conveyance of the recording paper 12 to the second conveyance path 67 by the third conveyance roller 45. That is, in this embodiment, in order to detect the presence or absence of gear switching, a dedicated sensor is not provided, but the second sensor 120 used for other purposes is used.

  As described above, in the present embodiment, it is possible to accurately determine whether or not the moved first gear 51 is engaged with the third gear 53, that is, the gear switching. In the present embodiment, since the determination is made based on the detection result based on the signal from the second sensor 120 for detecting the recording paper 12, a dedicated sensor for determining whether or not the gear is switched is combined. There is no need to add to the machine 10.

  In the present embodiment, the control unit 130 causes the recording paper 12 having the rear end in the first direction 15 to reach the first position 36 to be conveyed in the second direction in step S130. As a result, the recording paper 12 is conveyed from the first conveyance path 65 to the second conveyance path 67. Here, whether or not the rear end of the first direction 15 of the recording paper 12 has reached the first position 36 is determined based on the signal from the second sensor 120. The third conveyance from the detection of the recording paper 12 It can be obtained based on the rotation amount of the roller 45. That is, in the present embodiment, the second sensor 120 functions as a timing for determining the timing for transporting the recording paper 12 to the second transport path 67. That is, in the present embodiment, the second sensor 120 is not a dedicated sensor for detecting the presence / absence of gear switching. That is, the configuration of the multifunction machine 10 according to the present embodiment is a suitable configuration for enabling determination of whether or not to switch gears without adding a dedicated sensor.

  In the present embodiment, since the value of n is increased or decreased based on the detection result based on the signal from the second sensor 120, the number of forward / reverse drive for gear switching can be optimized. Thereby, the useless time consumed by the execution of forward / reverse drive for gear switching can be reduced.

  In this embodiment, since the value of n is determined using the actual data table, the value of n, which is the number of forward / reverse driving with the most actual gear switching, can be adopted as the number of forward / reverse driving. it can. Thereby, the useless time consumed by the execution of forward / reverse drive for gear switching can be reduced.

  The reason why the second sensor 120 detects the recording paper 12 after completion of the execution of step S70 is as follows. That is, the drive transmission switching mechanism 50 is switched to the second switching in the forward rotation driving up to the (n-1) th time in step S60, and the recording paper 12 is conveyed in the second direction by the subsequent reverse driving. Therefore, according to the present embodiment, the control unit 130 can accurately determine whether or not to switch to the second switching in the forward rotation driving up to the (n-1) th time.

  In the present embodiment, in step S170, the control unit 130 causes the transport motor 71 to perform forward rotation driving of the first rotation amount and reverse rotation driving of the second rotation amount larger than the first rotation amount. As a result, when the drive transmission switching mechanism 50 is switched to the second switching, the recording paper 12 is driven in the reverse rotation direction more than the amount that the recording paper 12 is conveyed in the first direction 15 by the transmission of the forward rotation driving. The amount conveyed in the second direction by transmission increases. As a result, the rear end of the first direction 15 of the sheet conveyed in the second direction by the reverse drive transmitted through the drive transmission switching mechanism 50 that has been switched to the second switching is from the downstream side of the first direction 15. It becomes easy to reach the second sensor 120. When the seat reaches the second sensor 120, the control unit 130 can determine that the gear switching has been executed.

[Modification of Embodiment]
In the above-mentioned embodiment, the control part 130 determined the value of n used by the process after step S50 based on a performance data table (S20-S40). However, the MFP 10 may have a configuration in which the actual data table is not stored in the RAM 133 or the like, that is, a configuration in which the value of n is determined by other than the actual data table.

  For example, one value of n may be stored in the RAM 133 instead of the performance data table. In this case, the RAM 133 is an example of the second storage unit of the present invention. In this case, the flowchart of FIG. 10 is executed instead of the flowchart of FIG. In the flowchart of FIG. 10, as indicated by the wavy line, step S110 of the flowchart of FIG. 8 is replaced with step S410, and steps S20 to S40 of the flowchart of FIG. 8 are replaced with steps S420 to S440. Hereinafter, the processing in steps S410 to S440 will be described.

  In step S <b> 420, the control unit 130 determines whether or not the value of n is stored in the RAM 133. When the value of n is stored in the RAM 133 (S420: Yes), the stored value of n is used in the processing after step S50 (S440). When the value of n is not stored in the RAM 133 (S420: No), the value of n is set to “1” (S430). The process of step S440 is an example of a second determination unit of the present invention.

  In step S410, the control unit 130 stores the value of n at that time in the RAM 133. Thereby, when a series of processes relating to the next image recording is executed, when Steps S420 to S440 are executed, the value of n stored in Step S410 is used in the processes after Step S50. The process of step S410 is an example of an n-value storage unit of the present invention.

  In the modification, the value of n, which is the number of forward / reverse driving required for the latest gear switching, is also used for the forward / reverse driving of the next gear switching. It is highly possible that the number of forward / reverse drive required for the next gear change is the same as the number of forward / reverse drive required for the most recent gear change. Therefore, in the modified example, it is possible to reduce wasted time consumed by executing the forward / reverse drive for gear switching.

DESCRIPTION OF SYMBOLS 10 ... Multifunction machine 12 ... Recording paper 15 ... 1st direction 24 ... Recording part 36 ... 1st position 45 ... 3rd conveyance roller 50 ... Drive transmission switching mechanism 51- ..First gear 52 ... second gear 53 ... third gear 54 ... first transmission part 57 ... second transmission part 65 ... first transport path 67 ... second transport Path 71 ... Conveyance motor 110 ... First sensor 120 ... Second sensor 130 ... Control unit

Claims (7)

A recording unit for recording an image on a sheet conveyed in the first direction on the first conveyance path;
A first detection unit that is provided upstream of the recording unit in the first direction and detects a sheet conveyed through the first conveyance path;
A conveyance roller provided downstream of the recording unit in the first direction, wherein the sheet is conveyed in the first direction by rotating in the first rotation direction, and is opposite to the first rotation direction. By rotating in the second rotation direction, the sheet is conveyed in a second direction opposite to the first direction, and the sheet is connected to the first conveyance path at a first position between the conveyance roller and the recording unit. A transport roller for transporting along the second transport path,
A second detection unit that is provided between the recording unit and the first position and detects a sheet conveyed through the first conveyance path;
A driving source for applying a driving force to the conveying roller by being driven forward and reversely;
A first switch that transmits the forward rotation drive of the drive source to the transport roller to rotate the transport roller in the first rotation direction, and does not transmit the reverse drive of the drive source to the transport roller; and the drive The forward rotation drive of the source is transmitted to the transport roller to rotate the transport roller in the first rotation direction, and the reverse drive of the drive source is transmitted to the transport roller to cause the transport roller to rotate in the second rotation direction. A drive transmission switching mechanism for selectively switching the second switching to be rotated to
A control unit for controlling the drive source and the drive transmission switching mechanism,
The drive transmission switching mechanism is
A first gear that rotates with the driving force from the driving source and moves to a second position and a third position;
A second gear meshing with the first gear in the second position;
A third gear meshing with the first gear in the third position;
A first transmission unit that transmits the rotational driving force of the second gear to the transport roller according to the transmission of the first switching;
A second transmission portion for transmitting the rotational driving force of the third gear to the transport roller according to the transmission of the second switching,
The control unit
Based on the detection signal of the first detection unit, the normal rotation drive with the first rotation amount of one rotation or less by the drive source is performed n times, and the normal rotation drive is smaller than the conveyance amount by which the sheet is conveyed. Is performed n-1 times, the sheet is moved to the fourth position on the upstream side in the first direction from the second detection unit by a set conveyance amount larger than the conveyance amount in which the sheet is conveyed. Stop means for stopping the sheet so that the end is positioned;
On condition that the execution of the stopping means is completed, the first gear is moved from the second position to the third position, and the forward rotation driving and the reverse driving of the first rotation amount of the driving source are alternately performed. first driving means for executing n-1 times;
Second driving means for driving the driving source to rotate forward at the first rotation amount on condition that the execution of the first driving means is completed;
Third driving the drive source in reverse rotation at the first rotation amount on condition that the second detection unit does not detect the sheet after the execution of the forward drive of the drive source by the second drive means is completed. Driving means;
On the condition that the second detection unit is in a state of detecting the sheet after the reverse drive of the drive source by the third drive means is completed, the drive source is driven forward so that the sheet is directed in the first direction. An image recording apparatus comprising: a first transport unit that transports the image recording apparatus. A rotation amount detecting means for detecting the rotation amount of the conveying roller;
Secondly, the drive source is driven in reverse to convey the sheet in the second direction on condition that the trailing edge in the first direction of the sheet conveyed by the first conveying means has reached the first position. The image recording apparatus according to claim 1, further comprising a conveying unit. The control unit
Used in the next execution of the stop means and the first drive means on condition that the second detection unit is in a state of detecting the sheet after the execution of the forward rotation drive of the drive source by the second drive means. Reducing means for reducing the value of n,
Used in the next execution of the stop means and the first drive means on the condition that the second detection unit is in a state in which the sheet is not detected after the execution of the reverse drive of the drive source by the third drive means. The image recording apparatus according to claim 1, further comprising an increasing unit that increases the value of n. a first storage unit that stores each value of n and a count value corresponding to each value;
The control unit
A count value that increments a count value corresponding to the value of n at that time on condition that the second detection unit is in a state of detecting a sheet after the execution of reverse drive of the drive source by the third drive unit is completed. Change means,
First determining means for setting the value of n having the largest count value among the values of n stored in the first storage unit as a value of n used in the execution of the stopping means and the first driving means; The image recording apparatus according to claim 3, further comprising: a second storage unit for storing a value of n;
The control unit
On the condition that the second detection unit is in a state of detecting a sheet after the execution of reverse drive of the drive source by the third drive unit is completed, the value of n at that time is stored in the second storage unit n Value storage means;
3. The second determination unit according to claim 1, further comprising: a second determination unit that sets the value of n stored by the n-value storage unit as a value of n used in the execution of the stop unit and the first drive unit. Image recording device. The first conveying means includes
The sheet according to any one of claims 1 to 5, wherein the sheet is conveyed in the first direction on condition that the second detection unit is in a state of detecting the sheet after the execution of the second driving unit is completed. Image recording device. The control unit
On the condition that the second detection unit does not detect the sheet after the execution of the third drive means is completed, the drive source is rotated forward with the first rotation amount and the first rotation amount greater than the first rotation amount. Fourth driving means for executing reverse rotation driving of two rotation amounts;
Whether or not the number of execution times of the fourth driving means has become greater than a preset number of times on condition that the second detection unit does not detect a sheet after the execution of the fourth driving means is completed. Determination means for determining;
And a third conveying means for conveying the sheet in the second direction by driving the drive source in the reverse direction on the condition that the determining means determines that the number of execution times is greater than the set number of times. ,
The first conveying unit conveys the sheet in the first direction on condition that the second detection unit is in a state of detecting the sheet after completion of execution of the fourth driving unit.
7. The image recording apparatus according to claim 1, wherein the fourth driving unit is executed on the condition that the determination unit determines that the number of executions is equal to or less than the set number of times. .

Images