Medium conveying device, recording device, and method for controlling medium conveying device

Abstract

To provide a medium conveying device, a recording device, and a method for controlling a medium conveying device that suppress decrease in processing.SOLUTION: A medium conveying device 16 includes a feeding roller 32 that feeds media 99, a conveying roller that conveys the medium fed by the feeding roller, a registration roller 44 that corrects skew of the medium conveyed by the conveying roller, a conveying path 23 extending from the feeding roller toward the registration roller, and a control part that rotates the conveying roller to convey the medium at a first speed and rotates the registration roller to convey the medium at a second speed which is faster than the first speed; the conveying path has a curved portion that extends while curving between the conveying roller and the registration roller, and the control part rotates the feeding roller so that a subsequent medium M2 fed after a preceding medium M1 overlaps the preceding medium until the leading edge of the preceding medium reaches the registration roller.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a medium transport device, a recording device, and a method for controlling a medium transport device. [Background technology]

[0002] Patent Document 1 describes a medium transport device that includes a feed roller that feeds a medium, a transport roller that transports the fed medium, and a registration roller that corrects skew of the transported medium. The registration roller corrects skew of the medium by being struck by the leading edge of the medium. The transport roller transports the medium along a transport path that includes a curved portion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-109837 Summary of the Invention [Problem to be solved by the invention]

[0004] In such media transport devices, if the leading edge of the media rubs against the curved section, paper dust may be generated from the media or the media may become electrostatically charged. Therefore, the media must be transported at a slow speed in the curved section. However, transporting the media at a slow speed reduces the media processing speed. [Means for solving the problem]

[0005] A media transport device that solves the above problem comprises a feed roller that feeds media, a transport roller that transports the media fed by the feed roller, a registration roller that corrects skew of the media transported by the transport roller, a transport path extending from the feed roller toward the registration roller, and a control unit that rotates the transport roller to transport the media at a first speed and rotates the registration roller to transport the media at a second speed greater than the first speed, wherein the transport path has a curved portion that extends while curving between the transport roller and the registration roller, and the control unit rotates the feed roller so that a subsequent medium fed after the preceding medium overlaps the preceding medium until the leading edge of the preceding medium reaches the registration roller.

[0006] A recording device that solves the above problem includes the above medium transport device and a recording unit that records an image on the medium transported by the medium transport device, and the medium transport device continuously transports the medium during recording.

[0007] A recording device that solves the above problem includes the medium transport device and a recording unit that records an image on the medium transported by the medium transport device. A control method for a media transport device that solves the above problem includes a feed roller that feeds media, a transport roller that transports the media fed by the feed roller, a registration roller that corrects skew of the media transported by the transport roller, and a transport path extending from the feed roller toward the registration roller, wherein the transport path includes a curved portion that extends while curving between the transport roller and the registration roller, and includes rotating the transport roller so as to transport a medium whose leading edge is located in the transport path at a first speed, rotating the registration roller so as to transport a medium whose leading edge has reached the registration roller at a second speed that is greater than the first speed, and rotating the feed roller so that a subsequent medium fed after the leading medium overlaps the leading medium until the leading edge of the leading medium reaches the registration roller.

[0008] A control method for a media transport device that solves the above problem includes a feed roller that feeds media, a transport roller that transports the media fed by the feed roller, a registration roller that corrects skew of the media transported by the transport roller, and a transport path extending from the feed roller toward the registration roller, wherein the transport path includes a curved portion that extends while curving between the transport roller and the registration roller, and an upstream portion that is located upstream of the curved portion and has a smaller curvature than the curved portion.The control method includes rotating the transport roller so as to transport media whose leading edge is located in the curved portion at a first speed, rotating the transport roller so as to transport media whose leading edge is located in the upstream portion at a second speed that is greater than the first speed, rotating the registration roller so as to transport media whose leading edge has reached the registration roller at the second speed, and rotating the feed roller so that a subsequent medium fed after the leading medium overlaps the leading medium until the leading edge of the leading medium reaches the registration roller. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing an embodiment of a recording apparatus equipped with a medium transport device. [Figure 2] FIG. 2 is a schematic diagram showing the feeding of the preceding medium. [Figure 3] FIG. 3 is a schematic diagram showing the feeding of the subsequent medium. [Figure 4] FIG. 4 is a schematic diagram showing feeding of a succeeding medium while overlapping the preceding medium. [Figure 5] FIG. 5 is a schematic diagram of the first pattern when the leading edge of the preceding medium reaches the registration roller. [Figure 6] FIG. 6 is a schematic diagram of the first pattern when the trailing edge of the preceding medium passes the third transport roller. [Figure 7]FIG. 7 is a schematic diagram of the first pattern when the trailing edge of the preceding medium passes the second transport roller. [Figure 8] FIG. 8 is a schematic diagram of the first pattern when the trailing edge of the preceding medium passes the first transport roller. [Figure 9] FIG. 9 is a schematic diagram of the first pattern when the trailing edge of the preceding medium passes through the registration roller. [Figure 10] FIG. 10 is a schematic diagram of the first pattern when the leading edge of the succeeding medium reaches the registration roller. [Figure 11] FIG. 11 is a schematic diagram of the second pattern when the leading edge of the preceding medium reaches the registration roller. [Figure 12] FIG. 12 is a schematic diagram of the second pattern when the trailing edge of the preceding medium passes the third transport roller. [Figure 13] FIG. 13 is a schematic diagram of the second pattern when the trailing edge of the preceding medium passes the second transport roller. [Figure 14] FIG. 14 is a schematic diagram of the second pattern when the trailing edge of the preceding medium passes the first transport roller. [Figure 15] FIG. 15 is a schematic diagram of the second pattern when the trailing edge of the preceding medium passes through the registration rollers. [Figure 16] FIG. 16 is a schematic diagram of the second pattern when the leading edge of the succeeding medium reaches the registration roller. [Figure 17] FIG. 17 is a flowchart showing the first conveying process. [Figure 18] FIG. 18 is a flowchart showing the overlapping forming process. [Figure 19] FIG. 19 is a flowchart showing the second conveying process. DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment of a recording device including a medium transport device will be described below with reference to the drawings. The recording device is an inkjet printer that records images such as text and photographs by ejecting ink, which is an example of a liquid, onto a medium such as paper.

[0011] <Recording device> As shown in FIG. 1, the recording device 11 includes a housing 12. The recording device 11 includes a recording unit 13. The recording unit 13 is configured to record an image on a medium 99. In one example, the recording unit 13 records an image on the medium 99 by ejecting a liquid onto the medium 99. The recording unit 13 is configured to eject the liquid simultaneously across the entire width of the medium 99. The recording unit 13 is a so-called line head. The recording unit 13 may also be configured to eject the liquid while scanning the medium 99. In this case, the recording unit 13 is a so-called serial head. The recording unit 13 is not limited to an inkjet printer, and may record an image on the medium 99 by fixing toner on the medium 99. The recording device 11 is not limited to an inkjet printer, and may also be a laser printer.

[0012] The recording device 11 may include an operation unit 14. A user operates the recording device 11 through the operation unit 14. By operating the operation unit 14, the user inputs information into the recording device 11 and gives instructions to the recording device 11. The operation unit 14 is, for example, a touch panel. The operation unit 14 may include switches, buttons, levers, etc.

[0013] The recording device 11 may be configured to communicate with a control terminal 15. A user operates the control terminal 15 to operate the recording device 11. By operating the control terminal 15, the user inputs information into the recording device 11 and gives instructions to the recording device 11. The control terminal 15 is a smartphone, a personal computer, or the like.

[0014] The recording device 11 includes a medium transport device 16. The medium transport device 16 is configured to transport a medium 99. The medium transport device 16 transports the medium 99 within the housing 12. In the recording device 11, the medium transport device 16 transports the medium 99 before recording to the recording unit 13. That is, the recording unit 13 records an image on the medium 99 transported by the medium transport device 16. In one example, the medium transport device 16 continuously transports the medium 99 during recording. This is because the recording unit 13 is a line head. A line head can eject liquid simultaneously across the entire width of the medium 99, so there is no need to stop the medium 99 during recording. If the recording unit 13 is a serial head, the medium transport device 16 intermittently transports the medium 99 during recording. In the case of a serial head, it is necessary to stop transporting the medium 99 while the recording unit 13 scans the medium 99. In the recording device 11, the medium transport device 16 ejects the recorded medium 99 from the housing 12.

[0015] <Media transport device> The medium transport device 16 may include a transport belt 17. The transport belt 17 faces the recording unit 13. The transport belt 17 supports the medium 99. The transport belt 17 supports the medium 99 during recording. The medium transport device 16 may include a support table that supports the medium 99 instead of the transport belt 17.

[0016] The medium conveying device 16 is configured to attract the medium 99 to the conveying belt 17. In one example, the medium 99 is attracted to the conveying belt 17 by electrostatic force. This stabilizes the position of the medium 99 on the conveying belt 17. As a result, the recording quality is improved. The medium 99 may be attracted to the conveying belt 17 by, for example, negative pressure due to suction, instead of electrostatic force.

[0017] The conveyor belt 17 is configured to convey the medium 99. The conveyor belt 17 is configured to convey the medium 99 while adsorbing it. The conveyor belt 17 conveys the medium 99 by rotating. In one example, the conveyor belt 17 conveys the medium 99 continuously. That is, the conveyor belt 17 conveys the medium 99 without stopping it during recording. The conveyor belt 17 may also convey the medium 99 intermittently. In this case, the conveyor belt 17 and the recording unit 13 repeatedly convey the medium 99, stop it, and record on it in sequence.

[0018] The medium transport device 16 may include multiple pulleys. In one example, the medium transport device 16 includes a first pulley 18 and a second pulley 19. A transport belt 17 is wound around the first pulley 18 and the second pulley 19. As the first pulley 18 and the second pulley 19 rotate, the transport belt 17 rotates.

[0019] The medium conveying device 16 includes a stacking unit 21. The stacking unit 21 is configured to stack a plurality of media 99. The media 99 before recording are stacked on the stacking unit 21. In one example, the stacking unit 21 is a cassette. The stacking unit 21 is configured to be insertable into and removable from the housing 12. The stacking unit 21 is not limited to a cassette, and may be a tray.

[0020] The medium conveying device 16 includes a conveying path 23. The conveying path 23 is a path along which the medium 99 is conveyed. The conveying path 23 extends from the stacking unit 21. In one example, the conveying path 23 extends from the stacking unit 21 toward the recording unit 13. The conveying path 23 extends while curving from the stacking unit 21 to the recording unit 13. The medium 99 is conveyed from the stacking unit 21 to the recording unit 13 via the conveying path 23.

[0021] The conveying path 23 has one or more curved portions. In one example, the conveying path 23 has a first curved portion 24 and a second curved portion 25. The curved portions are curved portions of the conveying path 23. The first curved portion 24 is located downstream of the second curved portion 25 on the conveying path 23.

[0022] The conveying path 23 has an upstream portion 26. The upstream portion 26 is located upstream of the first curved portion 24 on the conveying path 23. The curvature of the upstream portion 26 is smaller than the curvature of the first curved portion 24. The curvature of the upstream portion 26 is smaller than the curvature of the second curved portion 25. In one example, the upstream portion 26 is a portion of the conveying path 23 that extends linearly upstream of the first curved portion 24. The upstream portion 26 is connected to the first curved portion 24. In one example, the upstream portion 26 is located between the first curved portion 24 and the second curved portion 25. The upstream portion 26 is connected to the first curved portion 24 and the second curved portion 25.

[0023] Note that upstream portion 26 is not limited to a portion that extends linearly. In other words, upstream portion 26 may include a portion that is curved to the extent that problems such as the generation of paper dust and static electricity are unlikely to occur when medium 99 is transported at the relatively high second speed. Therefore, it can be said that a curved portion is a portion that is curved to the extent that problems such as the generation of paper dust and static electricity are likely to occur when medium 99 is transported at the relatively high second speed.

[0024] The transport path 23 may have a connection portion 27. The connection portion 27 is a portion of the transport path 23 that connects to the transport belt 17. The medium 99 is transported to the transport belt 17 through the connection portion 27. The connection portion 27 is located downstream of the first curved portion 24 in the transport path 23. The connection portion 27 is connected to the first curved portion 24. The connection portion 27 extends linearly from the first curved portion 24 toward the transport belt 17.

[0025] The medium transport device 16 may include an ejection path 28. The ejection path 28 is a path along which the medium 99 is ejected. In one example, the ejection path 28 is a path along which the recorded medium 99 is ejected. The ejection path 28 extends from the transport belt 17 toward the outside of the housing 12. The medium 99 is ejected to the outside of the housing 12 through the ejection path 28.

[0026] The medium transport device 16 may include a re-transport path 29. The re-transport path 29 is a path that extends from the discharge path 28 to the transport path 23. The medium 99 is returned from the discharge path 28 to the transport path 23 via the re-transport path 29. The medium 99 is switched back on the re-transport path 29. Therefore, when the medium 99 is returned from the discharge path 28 to the transport path 23 via the re-transport path 29, the front and back of the medium 99 are reversed. This allows the recording device 11 to record images on both sides of the medium 99.

[0027] The medium transport device 16 includes a feeding unit 31. The feeding unit 31 is configured to feed the medium 99. The feeding unit 31 feeds the medium 99 from the stacking unit 21. More specifically, the feeding unit 31 feeds the medium 99 toward the transport unit 36, which will be described later.

[0028] The feeding unit 31 feeds the medium 99 along the transport path 23. More specifically, the feeding unit 31 feeds the medium 99 to the transport unit 36 ​​along the transport path 23. The feeding unit 31 feeds the medium 99 to the transport unit 36 ​​through the second curved portion 25.

[0029] The feeding section 31 has a feeding roller 32. The feeding roller 32 feeds the medium 99 by rotating. The feeding roller 32 is positioned so as to come into contact with the medium 99 stacked in the stacking section 21. In one example, the feeding roller 32 comes into contact with the uppermost medium 99 among the media 99 stacked in the stacking section 21. The feeding roller 32 feeds the medium 99 one sheet at a time from the stacking section 21. The feeding roller 32 feeds the medium 99 along the transport path 23. The feeding roller 32 feeds the medium 99 along the second curved portion 25.

[0030] The feeding unit 31 has a feeding motor 33. The feeding motor 33 is connected to the feeding roller 32. The feeding roller 32 is rotated by the power of the feeding motor 33. The feed unit 31 has a feed clutch 34. The feed clutch 34 is connected to the feed roller 32 and the feed motor 33. The feed clutch 34 is located between the feed roller 32 and the feed motor 33. The feed clutch 34 is configured to transmit the power of the feed motor 33 to the feed roller 32. The feed clutch 34 is configured to be able to interrupt the power transmission between the feed roller 32 and the feed motor 33. When the feed clutch 34 interrupts the power transmission, the feed roller 32 is in a state where it does not apply a feeding force to the medium 99. In this case, the feed roller 32 is able to rotate in response to the medium 99.

[0031] The medium transport device 16 includes a transport unit 36. The transport unit 36 ​​is configured to transport the medium 99. The transport unit 36 ​​transports the medium 99 fed by the feeding unit 31. The transport unit 36 ​​transports the medium 99 along the transport path 23. In one example, the transport unit 36 ​​transports the medium 99 toward the recording unit 13.

[0032] The transport unit 36 ​​has one or more transport rollers. In one example, the transport unit 36 ​​has three transport rollers. The transport unit 36 ​​has a first transport roller 37, a second transport roller 38, and a third transport roller 39. The transport rollers transport the medium 99 fed by the feed roller 32.

[0033] The multiple transport rollers are arranged along the transport path 23. The first transport roller 37, the second transport roller 38, and the third transport roller 39 are arranged in this order from downstream to upstream of the transport path 23. That is, the first transport roller 37 is located downstream of the second transport roller 38 and the third transport roller 39 in the transport path 23. The second transport roller 38 is located downstream of the third transport roller 39 in the transport path 23. In one example, the first transport roller 37, the second transport roller 38, and the third transport roller 39 are located in the upstream portion 26. The transport rollers may be located in a curved portion. For example, the first transport roller 37 may be located in the first curved portion 24. The first transport roller 37 may be located upstream of the point at which the curvature of the first curved portion 24 is greatest. The third transport roller 39 may be located in the second curved portion 25. The third transport roller 39 may be located downstream of the point at which the curvature of the second curved portion 25 is greatest. Therefore, the second curved portion 25 can also be said to be a portion that extends while curving between the feed roller 32 and the transport roller.

[0034] The transport unit 36 ​​may be configured so that the rotation speed of the transport roller is variable. The transport unit 36 ​​may change the rotation speed of the transport roller by applying a voltage, or may change the rotation speed of the transport roller by changing a reduction ratio.

[0035] The transport unit 36 ​​has a transport motor 40. The transport motor 40 is connected to the transport rollers. In one example, the transport motor 40 is connected to a first transport roller 37, a second transport roller 38, and a third transport roller 39. The first transport roller 37, the second transport roller 38, and the third transport roller 39 are rotated by the power of the transport motor 40. The transport unit 36 ​​may have a transport motor 40 for each transport roller.

[0036] The conveying unit 36 ​​may have one or more conveying clutches. In one example, the conveying unit 36 ​​has three conveying clutches. The conveying unit 36 ​​has a first conveying clutch 41, a second conveying clutch 42, and a third conveying clutch 43.

[0037] The conveying clutches are connected to the conveying rollers and the conveying motor 40. The first conveying clutch 41 is connected to the first conveying roller 37 and the conveying motor 40. The second conveying clutch 42 is connected to the second conveying roller 38 and the conveying motor 40. The third conveying clutch 43 is connected to the third conveying roller 39 and the conveying motor 40.

[0038] The conveying clutches are positioned between the conveying rollers and the conveying motor 40. The first conveying clutch 41 is positioned between the first conveying roller 37 and the conveying motor 40. The second conveying clutch 42 is positioned between the second conveying roller 38 and the conveying motor 40. The third conveying clutch 43 is positioned between the third conveying roller 39 and the conveying motor 40.

[0039] The conveying clutches are configured to transmit the power of the conveying motor 40 to the conveying rollers. The first conveying clutch 41 is configured to transmit the power of the conveying motor 40 to the first conveying roller 37. The second conveying clutch 42 is configured to transmit the power of the conveying motor 40 to the second conveying roller 38. The third conveying clutch 43 is configured to transmit the power of the conveying motor 40 to the third conveying roller 39.

[0040] The transport clutch is configured to be able to interrupt power transmission between the transport roller and the transport motor 40. The first transport clutch 41 is configured to be able to interrupt power transmission between the first transport roller 37 and the transport motor 40. When the first transport clutch 41 interrupts power transmission, the first transport roller 37 is in a state where it does not apply a transport force to the medium 99. In this case, the first transport roller 37 is able to rotate in response to the medium 99. The second transport clutch 42 is configured to be able to interrupt power transmission between the second transport roller 38 and the transport motor 40. When the second transport clutch 42 interrupts power transmission, the second transport roller 38 is in a state where it does not apply a transport force to the medium 99. In this case, the second transport roller 38 is able to rotate in response to the medium 99. The third transport clutch 43 is configured to be able to interrupt power transmission between the third transport roller 39 and the transport motor 40. When the third transport clutch 43 interrupts power transmission, the third transport roller 39 is in a state where it does not apply a transport force to the medium 99. In this case, the third transport roller 39 is rotatable in response to the movement of the medium 99.

[0041] The transport unit 36 ​​may be configured to move the transport roller. For example, the transport unit 36 ​​may move the transport roller so that it switches between a state in contact with the medium 99 and a state away from the medium 99. That is, the transport roller may be configured to be movable to a position where it does not contact the medium 99 passing through the transport path 23. When the transport roller is away from the medium 99, it is in a state where it does not apply a transport force to the medium 99.

[0042] The conveying unit 36 ​​has a registration roller 44. The registration roller 44 is a roller that corrects skew of the medium 99. More specifically, the skew of the medium 99 is corrected by the medium 99 hitting the stopped registration roller 44. The medium 99 being conveyed along the conveying path 23 hits the registration roller 44.

[0043] The registration rollers 44 are located downstream of the transport rollers on the transport path 23. The medium 99 transported by the transport rollers abuts against the registration rollers 44. Therefore, it can be said that the transport path 23 extends from the feed rollers 32 toward the registration rollers 44. The registration rollers 44 correct any skew in the medium 99 transported by the transport rollers. The registration rollers 44 transport the medium 99 transported by the transport rollers.

[0044] The registration roller 44 is located downstream of the first curved portion 24. Specifically, the registration roller 44 is located downstream of the point in the first curved portion 24 where the curvature is greatest. Therefore, the leading edge of the medium 99 reaches the registration roller 44 after passing through the point in the first curved portion 24 where the curvature is greatest. In one example, the registration roller 44 is located downstream of the first curved portion 24. The registration roller 44 is located, for example, at the connection portion 27. The registration roller 44 may be located in the first curved portion 24 as long as it is downstream of the point in the first curved portion 24 where the curvature is greatest. From these facts, it can be said that the first curved portion 24 is a portion that extends while curving between the transport roller and the registration roller 44. In one example, the first curved portion 24 is located between the upstream portion 26 and the registration roller 44.

[0045] The registration rollers 44 are located upstream of the conveyor belt 17 on the conveyance path 23. The registration rollers 44 transport the medium 99 transported by the transport rollers to the conveyor belt 17. The registration rollers 44 transport the medium 99 during recording. In one example, the registration rollers 44 transport the medium 99 during recording together with the conveyor belt 17. Therefore, the registration rollers 44 transport the medium 99 at the same speed as the conveyor belt 17.

[0046] The conveying unit 36 ​​has a resist motor 45. The resist motor 45 is connected to the resist roller 44. The resist roller 44 rotates due to the power of the resist motor 45. The conveying unit 36 ​​may have a resist clutch that transmits or interrupts power transmission between the resist motor 45 and the resist roller 44.

[0047] The transport section 36 has a plurality of driven rollers. The transport section 36 has a driven roller that faces the transport roller and a driven roller that faces the registration roller 44. In one example, the transport section 36 has a first driven roller 46, a second driven roller 47, a third driven roller 48, and a fourth driven roller 49. The driven rollers rotate in response to the rotation of the opposing rollers. The first driven roller 46 faces the first transport roller 37. The second driven roller 47 faces the second transport roller 38. The third driven roller 48 faces the third transport roller 39. The fourth driven roller 49 faces the registration roller 44.

[0048] The medium transport device 16 includes a discharge unit 51. The discharge unit 51 is configured to discharge the medium 99. The discharge unit 51 discharges the medium 99 along the discharge path 28. The discharge unit 51 includes a discharge roller 52. The discharge unit 51 includes a sub-roller 53. The sub-roller 53 faces the discharge roller 52.

[0049] The medium conveying device 16 includes a detection unit 55. The detection unit 55 is configured to detect the medium 99. The detection unit 55 detects the medium 99 conveyed along the conveying path 23. The detection unit 55 has one or more detection sensors. In one example, the detection unit 55 has a first detection sensor 56 and a second detection sensor 57. The detection sensors are, for example, optical sensors. The first detection sensor 56 is located upstream of the second detection sensor 57 along the conveying path 23. The first detection sensor 56 is located upstream of the registration roller 44 along the conveying path 23. The second detection sensor 57 is located downstream of the registration roller 44 along the conveying path 23. The medium conveying device 16 determines that the medium 99 has reached the registration roller 44 when the first detection sensor 56 detects the leading edge of the medium 99. The medium conveying device 16 determines that the medium 99 has reached the recording unit 13 when the second detection sensor 57 detects the leading edge of the medium 99. The medium conveying device 16 detects that the medium 99 has passed the registration rollers 44 when the second detection sensor 57 detects the rear end of the medium 99 .

[0050] The medium conveying device 16 may include an acquisition unit 61. The acquisition unit 61 is configured to acquire information related to the conveyance of the medium 99. Information related to the conveyance of the medium 99 includes, for example, the size of the medium 99, the type of the medium 99, and the setting of the conveyance method. In the recording device 11, the information related to the conveyance of the medium 99 includes the setting of the recording method. The conveyance method may be high-speed conveyance that prioritizes processing speed, or low-speed conveyance that prioritizes quality. The recording method may be double-sided recording, single-sided recording, monochrome recording, full-color recording, etc.

[0051] The acquisition unit 61 may include an acquisition sensor 62. The acquisition sensor 62 is, for example, an optical sensor. The acquisition sensor 62 is positioned to face the media 99 loaded on the loading unit 21. The acquisition sensor 62 acquires information related to the transport of the media 99 from the media 99. For example, the acquisition sensor 62 acquires information such as the size and type of the media 99 by irradiating light onto the media 99.

[0052] The acquisition unit 61 includes a connector 63. The connector 63 is an interface connected to, for example, the operation unit 14, the control terminal 15, etc. The connector 63 acquires information related to the transportation of the medium 99 from the user via the operation unit 14, the control terminal 15, etc. In other words, the connector 63 acquires the size of the medium 99, the type of the medium 99, the transportation method setting, the recording method setting, etc., which are set via the operation unit 14, the control terminal 15, etc.

[0053] The medium conveying device 16 includes a control unit 65. The control unit 65 controls the medium conveying device 16. The control unit 65 controls the conveyor belt 17, the first pulley 18, the second pulley 19, the feeding unit 31, the conveying unit 36, the discharge unit 51, etc. The control unit 65 may also control the recording device 11. For example, the control unit 65 may also control the recording unit 13.

[0054] The control unit 65 may be configured with one or more processors that execute various processes according to a computer program. The control unit 65 may be configured with one or more dedicated hardware circuits, such as an ASIC, that execute at least some of the various processes. The control unit 65 may be configured as a circuit that includes a combination of a processor and a hardware circuit. The processor includes a CPU and memory, such as RAM and ROM. The memory stores program code or instructions configured to cause the CPU to execute processes. The memory, i.e., computer-readable medium, includes any readable medium that can be accessed by a general-purpose or dedicated computer.

[0055] The control unit 65 controls the feeding unit 31 and the conveying unit 36, so that the medium 99 is conveyed along the conveying path 23. At this time, if the leading edge of the medium 99 rubs against the curved portion, paper dust may be generated from the medium 99 or the medium 99 may become electrically charged. To prevent the generation of paper dust, charging, etc., the medium conveying device 16 needs to convey the medium 99, whose leading edge is located in the curved portion, at a low speed.

[0056] The control unit 65 controls the feeding unit 31 and the transport unit 36 ​​to transport the medium 99, whose leading edge is located in the curved portion, at a low speed. Specifically, the control unit 65 rotates the feeding roller 32 to feed the medium 99 at a first speed. The control unit 65 rotates the transport roller to transport the medium 99 at the first speed. The control unit 65 rotates the registration roller 44 to transport the medium 99 at a second speed. The second speed is a speed greater than the first speed. In one example, the second speed is the speed of the medium 99 during recording. By transporting the medium 99 at a speed relatively slower than the second speed, the control unit 65 suppresses the generation of paper dust, charging, and the like, compared to always transporting the medium 99 at the second speed.

[0057] If the medium 99 is transported at a low speed, the processing speed may decrease. In other words, the time required to transport the medium 99 may increase. Furthermore, if the transport roller transports the medium 99 at a low speed relative to the registration rollers 44, the transport interval of the medium 99 may increase. For example, the interval at which the medium 99 reaches the recording unit 13 may increase.

[0058] The control unit 65 controls the feeding unit 31 and the transport unit 36 ​​so as to reduce the transport interval of the medium 99. In one example, the control unit 65 controls the feeding unit 31 and the transport unit 36 ​​so as to reduce the interval at which the medium 99 reaches the recording unit 13. This prevents a decrease in processing speed.

[0059] The control unit 65 controls the feeding unit 31 and the transport unit 36 ​​so that the media 99 are transported while overlapping each other, in order to reduce the transport interval between the media 99. More specifically, the control unit 65 controls the feeding unit 31 and the transport unit 36 ​​so that the media 99 are transported while overlapping each other. The control unit 65 rotates the feeding roller 32 and the transport roller so that the media 99 are transported while overlapping each other. By overlapping the media 99, the control unit 65 prevents a decrease in processing speed.

[0060] The difference in speed between the registration rollers 44 and the transport rollers gradually eliminates overlaps between the media 99. That is, the overlaps between the media 99 are gradually eliminated as the media 99 are transported along the transport path 23. The later the timing at which the overlaps between the media 99 are eliminated, the faster the processing speed. For example, the later the timing at which the overlaps between the media 99 are eliminated, the shorter the interval at which the media 99 reach the recording unit 13.

[0061] While the processing speed improves as the timing at which overlapping media 99 are eliminated increases, elimination of overlapping media 99 too late may result in a decrease in quality. For example, if overlapping media 99 reach the recording unit 13, recording quality may be affected. For example, if overlapping media 99 reach the conveyor belt 17, recording quality may be affected. Therefore, the overlap between the preceding medium 99 and the succeeding medium 99 must be eliminated at least by the time the succeeding medium 99 reaches the recording unit 13. Preferably, the overlap between the preceding medium 99 and the succeeding medium 99 is eliminated by the time the succeeding medium 99 reaches the conveyor belt 17. In this case, the medium 99 is effectively adsorbed to the conveyor belt 17. More preferably, the overlap between the preceding medium 99 and the succeeding medium 99 is eliminated by the time the succeeding medium 99 reaches the registration roller 44. In this case, the succeeding medium 99 can be abutted against the registration roller 44. That is, skew can be corrected for the succeeding medium 99 without stopping the transport of the preceding medium 99.

[0062] The control unit 65 conveys the media 99 in a manner that eliminates overlaps between the media 99, in order to reduce the conveyance intervals between the media 99. Specifically, the control unit 65 controls the feeding unit 31 and the conveying unit 36 ​​to eliminate overlaps between the media 99. The control unit 65 rotates the feeding roller 32 and the conveying rollers to eliminate overlaps between the media 99. By eliminating overlaps between the media 99, the control unit 65 suppresses deterioration in quality.

[0063] The control unit 65 may be configured to be able to execute a first mode and a second mode. The first mode is a mode in which the media 99 are transported while overlapping each other. The second mode is a mode in which the media 99 are transported without overlapping each other. Specifically, the first mode is a mode in which the feed roller 32 is rotated so that the preceding medium 99 and the next medium 99 are overlapped. The second mode is a mode in which the feed roller 32 is rotated so that the preceding medium 99 and the next medium 99 are not overlapped.

[0064] The control unit 65 selects the first mode or the second mode based on the user's operation of the operation unit 14, the control terminal 15, or the like. For example, if the user places importance on suppressing paper dust generation and suppressing static electricity, the control unit 65 can select the first mode. If the user places importance on processing speed over suppressing paper dust generation and suppressing static electricity, the control unit 65 can select the second mode and set the conveying speed to a relatively high second speed. Alternatively, for example, if the user places importance on suppressing paper dust generation and suppressing static electricity while also placing importance on processing speed, the control unit 65 can select the first mode. If the user places importance on suppressing paper dust generation and suppressing static electricity while also placing importance on quality, the control unit 65 can select the second mode and set the conveying speed to a relatively low first speed. This allows the medium conveying device 16 to operate in accordance with the user's needs.

[0065] <Media transport device control> Next, the control of the medium transport device 16 by the control unit 65 will be described in terms of transporting the media 99 while overlapping them.

[0066] As shown in Figures 2, 3, and 4, the control unit 65 controls the feeding unit 31 to feed the media 99 while overlapping each other. The control unit 65 rotates the feeding roller 32 to feed the media 99 while overlapping each other. The control unit 65 rotates the feeding roller 32 to feed the preceding medium M1 and the following medium M2 while overlapping each other. The preceding medium M1 is the medium 99 preceding the following medium M2. The preceding medium M1 is, for example, the first sheet of medium 99. The following medium M2 is the medium 99 following the preceding medium M1. The following medium M2 is the medium 99 fed next to the preceding medium M1. The following medium M2 is, for example, the second sheet of medium 99. The control unit 65 rotates the feeding roller 32 so that the leading end of the following medium M2 overlaps with the trailing end of the preceding medium M1.

[0067] The control unit 65 controls the rotation timing of the feed roller 32 to feed the media 99 while overlapping them. The control unit 65 controls the rotation timing of the feed roller 32, for example, by controlling the feed clutch 34. More specifically, the control unit 65 controls the rotation timing of the feed roller 32 by transmitting and disconnecting power. The control unit 65 controls the rotation timing of the feed roller 32 by turning the feed clutch 34 on and off. When the feed clutch 34 is turned on, power is transmitted to the feed roller 32. When the feed clutch 34 is turned off, power transmission to the feed roller 32 is disconnected. The control unit 65 repeatedly turns the feed clutch 34 on and off to feed the media 99 while overlapping them. In one example, the control unit 65 turns on the feed clutch 34 before the fed preceding medium M1 passes through the stacking unit 21, thereby feeding the following medium M2 while overlapping it on the preceding medium M1.

[0068] The control unit 65 may rotate the feed roller 32 so that the subsequent medium 99 is sequentially stacked on top of the preceding medium 99. For example, the control unit 65 may rotate the feed roller 32 so that the third medium 99 is stacked on top of the second medium 99.

[0069] The control unit 65 may rotate the feed roller 32 so that even-numbered media 99 overlap odd-numbered media 99. For example, the control unit 65 may rotate the feed roller 32 so that the second medium 99 overlaps the first medium 99, and then rotate the feed roller 32 so that the fourth medium 99 overlaps the third medium 99.

[0070] The control unit 65 may feed the media 99 while appropriately changing the way the media 99 are stacked. For example, the control unit 65 may rotate the feed roller 32 so that the second medium 99 is stacked on top of the first medium 99, and then rotate the feed roller 32 so that the third and subsequent media 99 are stacked sequentially.

[0071] The control unit 65 rotates the feed roller 32 to feed the medium 99 at a first speed. Specifically, the control unit 65 rotates the feed roller 32 to feed the medium 99, whose leading edge is located at the second curved portion 25, at the first speed. The control unit 65 turns on the feed clutch 34, thereby rotating the feed roller 32 to feed the medium 99 at the first speed. The control unit 65 turns off the feed clutch 34, thereby preventing the feed roller 32 from applying a feeding force to the medium 99. In this case, the feed roller 32 may rotate in response to the medium 99 being transported, but does not contribute to the transport of the medium 99. The leading edge of the medium 99 passing through the second curved portion 25 at the first speed reduces the generation of paper dust, static electricity, and the like.

[0072] The control unit 65 may rotate the feed roller 32 to feed the medium 99 at a speed different from the first speed. For example, the control unit 65 may rotate the feed roller 32 to feed the medium 99 at a speed slower than the first speed. In this case, the risk of paper dust being generated from the medium 99 or the medium 99 becoming electrically charged at the second curved portion 25 is further reduced. The control unit 65 may rotate the feed roller 32 to feed the medium 99 at a speed faster than the first speed. For example, the feed roller may be rotated to feed the medium 99 at a speed faster than the first speed and slower than the second speed. Even in this case, the risk of paper dust being generated from the medium 99 or the medium 99 becoming electrically charged can be reduced compared to feeding the medium 99 at the second speed. Furthermore, for example, when the transport path 23 does not have the second curved portion 25, the control unit 65 may cause the feed roller 32 to feed the medium 99 at a speed equal to or higher than the second speed.

[0073] The control unit 65 rotates the feed roller 32 so that the following medium M2 overlaps the preceding medium M1 until the leading edge of the preceding medium M1 reaches the registration roller 44. The control unit 65 controls the rotation timing of the feed roller 32 so that the following medium M2 overlaps the preceding medium M1 until the leading edge of the preceding medium M1 reaches the registration roller 44. The control unit 65 controls the amount of overlap between the media 99 by controlling the rotation timing of the feed roller 32. The control unit 65 rotates the feed roller 32 so that the following medium M2 overlaps the preceding medium M1 until the leading edge of the preceding medium M1 reaches the registration roller 44. This reduces the transport interval between the preceding medium M1 and the following medium M2.

[0074] When the feed roller 32 feeds the medium 99 at a first speed, the overlap amount of the following medium M2 with respect to the preceding medium M1 is maintained until the leading edge of the preceding medium M1 reaches the registration roller 44. When the feed roller 32 feeds the medium 99 at a speed different from the first speed, the overlap amount of the following medium M2 with respect to the preceding medium M1 changes until the leading edge of the preceding medium M1 reaches the registration roller 44.

[0075] The control unit 65 rotates the feed roller 32 so that the overlap between the preceding medium M1 and the following medium M2 is eliminated before the leading edge of the following medium M2 reaches the registration roller 44. The control unit 65 controls the rotation timing of the feed roller 32 so that the overlap between the preceding medium M1 and the following medium M2 is eliminated by the time the following medium M2 reaches the recording unit 13. That is, the control unit 65 rotates the feed roller 32 so that the overlap between the preceding medium M1 and the following medium M2 is eliminated by the time the leading edge of the following medium M2 reaches the registration roller 44. This suppresses deterioration in quality. The control unit 65 may rotate the feed roller 32 so that the overlap between the preceding medium M1 and the following medium M2 is eliminated before the leading edge of the following medium M2 reaches the recording unit 13. The control unit 65 may rotate the feed roller 32 so that the overlap between the preceding medium M1 and the following medium M2 is eliminated before the leading edge of the following medium M2 reaches the conveyor belt 17.

[0076] The control unit 65 determines the amount of overlap between the media 99 based on the transport information acquired by the acquisition unit 61. The control unit 65 rotates the feed roller 32 to achieve the amount of overlap determined based on the transport information. For example, when high-speed transport is set, which prioritizes processing speed, the control unit 65 increases the amount of overlap between the media 99. When low-speed transport is set, which prioritizes quality, the control unit 65 decreases the amount of overlap between the media 99. By reducing the amount of overlap between the media 99, the control unit 65 can reduce the speed difference between the first speed and the second speed. For example, by reducing the amount of overlap between the media 99, the control unit 65 can reduce the transport speed of the medium 99 by the registration roller 44. When the speed difference becomes smaller, it takes time to eliminate the amount of overlap, but this can be addressed by reducing the amount of overlap. In other words, the control unit 65 determines the amount of overlap depending on the speed difference between the first speed and the second speed. It is also possible to determine the amount of overlap between the media 99 based on information related to transport other than the transport speed, and to determine the first speed and the second speed according to the amount of overlap.

[0077] The control unit 65 controls the transport unit 36 ​​to transport the medium 99 at a first speed and a second speed. The control unit 65 rotates the transport roller to transport the medium 99 at the first speed. Specifically, the control unit 65 rotates the transport roller to transport the medium 99 whose leading edge is located in the first curved portion 24 at the first speed. As a result, the medium 99 whose leading edge is located in the first curved portion 24 is transported at the first speed. The control unit 65 may also rotate the transport roller to transport the medium 99 at a second speed. For example, the control unit 65 may rotate the transport roller to transport the medium 99 whose leading edge is located in the upstream portion 26 at the second speed. The control unit 65 may also rotate the transport roller to transport the medium 99 whose leading edge is located in the transport path 23 at the first speed. In other words, the control unit 65 may rotate the transport roller to transport the medium 99 in the transport path 23 at the first speed. In this case, the medium 99 is also transported at the first speed in the upstream portion 26.

[0078] The control unit 65 rotates the registration roller 44 to transport the medium 99 at the second speed. The control unit 65 rotates the registration roller 44 to transport the medium 99 at the second speed after the leading edge of the medium 99 has reached the registration roller 44. Specifically, the control unit 65 rotates the registration roller 44 to transport the medium 99, the skew of which has been corrected by the leading edge hitting the registration roller 44, at the second speed. When the transport roller transports the medium 99 at the first speed, a speed difference occurs between the leading medium M1 and the following medium M2 when the leading edge of the preceding medium M1 reaches the registration roller 44. Therefore, when the transport roller transports the medium 99 at the first speed, the leading medium M1 and the following medium M2 are transported while remaining overlapped, at least until the leading edge of the preceding medium M1 reaches the registration roller 44.

[0079] The medium 99 reaches the transport rollers when it is fed by the feed roller 32. Specifically, the leading edge of the medium 99 reaches the third transport roller 39. In one example, the medium 99 is fed at a first speed by the feed roller 32 and transported at the first speed by the third transport roller 39. Because there is no speed difference between the feed roller 32 and the third transport roller 39, the risk of stress being applied to the medium 99 that comes into contact with the feed roller 32 and the third transport roller 39 is reduced. If there is a speed difference between the feed roller 32 and the third transport roller 39, stress may be applied to the medium 99. Specifically, the third transport roller 39 may pull the medium 99 from the feed roller 32, causing the medium 99 to become stiff. The same applies to the first transport roller 37 and the second transport roller 38. The medium 99 is transported by the third transport roller 39 and reaches the second transport roller 38. The medium 99 is transported at a first speed by the second transport roller 38. Because there is no speed difference between the feed roller 32 and the second transport roller 38, the risk of stress being placed on the medium 99 is reduced. The medium 99 reaches the first transport roller 37 by being transported by the second transport roller 38. The medium 99 is transported at a first speed by the first transport roller 37. Because there is no speed difference between the feed roller 32 and the first transport roller 37, the risk of stress being placed on the medium 99 is reduced. When the leading edge of the medium 99 reaches the transport roller, the feed roller 32 may switch to a state where it does not apply a feeding force to the medium 99. In this case as well, the risk of the medium 99 becoming taut is reduced.

[0080] When medium 99 is transported by the transport rollers, it reaches registration rollers 44. More specifically, when medium 99 is transported by first transport rollers 37, it reaches registration rollers 44. Medium 99 is transported by registration rollers 44 at a second speed.

[0081] If there is a speed difference between the registration roller 44 and the transport roller, a load may be applied to the medium 99 that comes into contact with the registration roller 44 and the transport roller. For example, if there is a speed difference between the registration roller 44 and the first transport roller 37, a load may be applied to the medium 99. Specifically, the registration roller 44 may pull the medium 99 from the first transport roller 37, causing the medium 99 to become stiff. The same applies to the second transport roller 38 and the third transport roller 39. If there is a speed difference between the registration roller 44 and the second transport roller 38, a load may be applied to the medium 99. If there is a speed difference between the registration roller 44 and the third transport roller 39, a load may be applied to the medium 99.

[0082] The control unit 65 controls the transport unit 36 ​​so that the medium 99 is not tensed between the registration roller 44 and the transport roller. The control unit 65 controls the transport rollers so that the medium 99 is not tensed between the registration roller 44 and the transport roller. For example, when the leading edge of the medium 99 reaches the registration roller 44, the control unit 65 switches the transport rollers to a state where they do not apply a transport force to the medium 99. In one example, the control unit 65 switches the transport rollers to a state where they do not apply a transport force to the medium 99 by turning off the transport clutch. This reduces the risk of the medium 99 being tensed. The control unit 65 may also switch the transport rollers to a state where they do not apply a transport force to the medium 99 by moving the transport roller away from the driven roller. The control unit 65 may control one of the three transport rollers to turn off the transport clutch and move the other transport rollers away from the driven roller.

[0083] If the leading edge of the preceding medium M1 reaches the registration roller 44 and the transport rollers are switched to a state in which they do not apply a transport force to the medium 99, there is a risk that the following medium M2 will not be transported by the transport rollers. Therefore, when the trailing edge of the preceding medium M1 passes the transport roller, the control unit 65 switches the transport roller to a state in which it applies a transport force to the medium 99. For example, after the trailing edge of the preceding medium M1 passes the third transport roller 39, the third transport roller 39 is switched to a state in which it applies a transport force to the medium 99. This allows the third transport roller 39 to transport the following medium M2 without the preceding medium M1 being stretched. The same applies to the first transport roller 37 and the second transport roller 38. After the trailing edge of the preceding medium M1 passes the second transport roller 38, the control unit 65 switches the second transport roller 38 to a state in which it applies a transport force to the medium 99. After the trailing edge of the preceding medium M1 passes the first transport roller 37, the control unit 65 switches the first transport roller 37 to a state in which it applies a transport force to the medium 99.

[0084] The subsequent medium M2 is fed by the feed roller 32 until the third transport roller 39 switches to a state in which it applies a transport force to the medium 99. After switching the third transport roller 39 to a state in which it applies a transport force to the medium 99, the control unit 65 may switch the feed roller 32 to a state in which it does not apply a feed force to the medium 99. In this case, there is little risk that the feed roller 32 and the transport roller will apply a load to the medium 99.

[0085] The control unit 65 may rotate the transport rollers to transport the medium 99 at the second speed to prevent the medium 99 from being pulled between the registration rollers 44 and the transport rollers. Specifically, the control unit 65 may rotate the transport rollers to transport the medium 99 at the second speed when the leading edge of the medium 99 reaches the registration rollers 44. In this case, there is no speed difference between the registration rollers 44 and the transport rollers, so there is little risk of a load being applied to the medium 99.

[0086] When the leading edge of the preceding medium M1 reaches the registration rollers 44 and the transport rollers switch to the second speed, the following medium M2 is transported by the transport rollers at the second speed. In this case, there is a risk that the leading edge of the following medium M2 may pass through the first curved portion 24 at the second speed. Therefore, when the trailing edge of the preceding medium M1 passes the first transport roller 37, the control unit 65 switches the first transport roller 37, the second transport roller 38, and the third transport roller 39 to the first speed. After the trailing edge of the preceding medium M1 passes the first transport roller 37, the control unit 65 rotates the first transport roller 37, the second transport roller 38, and the third transport roller 39 so as to transport the following medium M2 at the first speed. This allows the following medium M2 to be transported at the first speed without the preceding medium M1 being tensed. In this case, when the trailing end of the preceding medium M1 passes the first transport roller 37, the leading end of the following medium M2 needs to be located upstream of the point with the greatest curvature in the first curved portion 24. Therefore, the control unit 65 controls the overlap amount so that when the trailing end of the preceding medium M1 passes the first transport roller 37, the leading end of the following medium M2 is located upstream of the point with the greatest curvature in the first curved portion 24.

[0087] When the leading edge of the preceding medium M1 reaches the registration roller 44 and the transport roller switches to the second speed, the transport roller transports the following medium M2 at the second speed. In this case, the difference in speed between the feed roller 32 and the transport roller may place a load on the following medium M2. Therefore, when the leading edge of the preceding medium M1 reaches the registration roller 44, the control unit 65 switches the feed roller 32 to a state where it does not apply a feeding force to the medium 99. This reduces the risk of a load being placed on the following medium M2 due to the difference in speed between the feed roller 32 and the transport roller. In this case, when the feed roller 32 switches to a state where it does not apply a feeding force, the leading edge of the following medium M2 needs to reach the third transport roller 39. Therefore, the control unit 65 controls the overlap amount so that the leading edge of the following medium M2 reaches the third transport roller 39 when the leading edge of the preceding medium M1 reaches the registration roller 44.

[0088] Next, a first pattern of control for transporting the medium 99 so that the medium 99 is not stretched between the registration roller 44 and the transport roller will be described with reference to Figures 5 to 10, and a second pattern will be described with reference to Figures 11 to 16. Note that the following description uses an example in which two sheets of media 99 are transported consecutively, but it goes without saying that the same can also be applied to the case in which three or more sheets of media 99 are transported.

[0089] First, the first pattern will be described. The first pattern is a pattern in which the transport clutch is turned off to prevent tension on the medium 99. In the first pattern, the transport motor 40 always rotates at the first speed.

[0090] 5, the control unit 65 turns off the transport clutch when the leading edge of the preceding medium M1 reaches the registration roller 44. Specifically, the control unit 65 corrects the skew of the preceding medium M1 and then turns off the first transport clutch 41, the second transport clutch 42, and the third transport clutch 43. In one example, when the leading edge of the preceding medium M1 reaches the registration roller 44, the rear end of the preceding medium M1 has not passed the third transport roller 39. When the leading edge of the preceding medium M1 reaches the registration roller 44, the leading edge of the following medium M2 has reached the third transport roller 39.

[0091] The control unit 65 may detect that the leading edge of the medium 99 has reached the registration rollers 44 by using the first detection sensor 56. The control unit 65 may detect that the leading edge of the medium 99 has reached the registration rollers 44 by counting time.

[0092] 6, the control unit 65 rotates the registration rollers 44 to transport the preceding medium M1 at the second speed. As a result, the trailing end of the preceding medium M1 passes the third transport rollers 39. At this time, the control unit 65 rotates the third transport rollers 39 to transport the following medium M2 at the first speed. That is, the control unit 65 turns on the third transport clutch 43.

[0093] 7, when the preceding medium M1 is transported by the registration rollers 44, the trailing end of the preceding medium M1 passes by the second transport rollers 38. At this time, the control unit 65 rotates the second transport rollers 38 so as to transport the following medium M2 at a first speed. That is, the control unit 65 turns on the second transport clutch 42. In one example, when the trailing end of the preceding medium M1 passes by the second transport rollers 38, the overlap between the preceding medium M1 and the following medium M2 is resolved.

[0094] 8, when the preceding medium M1 is transported by the registration rollers 44, the trailing end of the preceding medium M1 passes by the first transport rollers 37. At this time, the control unit 65 rotates the first transport rollers 37 so as to transport the following medium M2 at a first speed. That is, the control unit 65 turns on the first transport clutch 41.

[0095] As shown in FIG. 9, when the preceding medium M1 is transported by the registration rollers 44, the trailing end of the preceding medium M1 passes through the registration rollers 44. At this time, the control unit 65 stops the registration rollers 44. This allows the registration rollers 44 to correct the skew of the following medium M2 while continuing to transport the preceding medium M1. In this way, to correct the skew of the following medium M2, the trailing end of the preceding medium M1 needs to pass through the registration rollers 44 before the leading end of the following medium M2 reaches the registration rollers 44. In one example, when the trailing end of the preceding medium M1 passes through the registration rollers 44, the leading end of the following medium M2 is positioned at the first curved portion 24.

[0096] The control unit 65 may detect that the rear end of the medium 99 has passed the registration rollers 44 by using the second detection sensor 57. The control unit 65 may detect that the rear end of the medium 99 has passed the registration rollers 44 by counting time.

[0097] The control unit 65 rotates the first transport roller 37, the second transport roller 38, and the third transport roller 39 to transport the following medium M2, whose leading edge is located in the first curved portion 24, at a first speed. This suppresses the generation of paper dust, static electricity, and the like on the following medium M2.

[0098] 10, the control unit 65 turns off the transport clutch when the leading edge of the following medium M2 reaches the registration roller 44. Specifically, the control unit 65 corrects the skew of the following medium M2, and then turns off the first transport clutch 41, the second transport clutch 42, and the third transport clutch 43. The control unit 65 rotates the registration roller 44 so as to transport the following medium M2 at the second speed.

[0099] Next, the second pattern will be described. The second pattern is a pattern in which tension of the medium 99 is suppressed by rotating the transport roller at a second speed. As shown in FIG. 11 , when the leading edge of the preceding medium M1 reaches the registration rollers 44, the control unit 65 rotates the transport rollers to transport the preceding medium M1 at the second speed. Specifically, the control unit 65 corrects the skew of the preceding medium M1 and then rotates the transport rollers to transport the preceding medium M1 at the second speed. When the leading edge of the preceding medium M1 reaches the registration rollers 44, the control unit 65 switches the transport rollers from the first speed to the second speed. In one example, when the leading edge of the preceding medium M1 reaches the registration rollers 44, the rear end of the preceding medium M1 has not passed the third transport roller 39. On the other hand, when the leading edge of the preceding medium M1 reaches the registration rollers 44, the leading edge of the following medium M2 has reached the third transport roller 39. In other words, the leading edge of the following medium M2 has passed the second curved portion 25. Because the leading edge of the following medium M2 is located in the upstream portion 26, there is no problem even if the following medium M2 is transported at the second speed.

[0100] 12 and 13, the control unit 65 rotates the registration rollers 44 to transport the preceding medium M1 at the second speed. The control unit 65 rotates the first transport roller 37, the second transport roller 38, and the third transport roller 39 at the second speed to transport the preceding medium M1 at the second speed. Accordingly, the following medium M2 is also transported at the second speed.

[0101] As shown in FIG. 14 , when the preceding medium M1 is transported, the trailing end of the preceding medium M1 passes the first transport roller 37. At this time, the control unit 65 rotates the transport rollers to transport the following medium M2 at a first speed. Specifically, the control unit 65 rotates the first transport roller 37, the second transport roller 38, and the third transport roller 39 to transport the following medium M2 at the first speed. When the trailing end of the preceding medium M1 passes the first transport roller 37, the control unit 65 switches the transport rollers from the first speed to the second speed. In one example, when the trailing end of the preceding medium M1 passes the first transport roller 37, the leading end of the following medium M2 is positioned in the first curved portion 24. The leading end of the following medium M2 does not pass through the part of the first curved portion 24 with the largest curvature. Therefore, transporting the following medium M2 at the first speed suppresses the generation of paper dust, charging, and the like. When the trailing end of the preceding medium M1 has passed the first transport roller 37, the leading end of the following medium M2 may be located in the upstream portion .

[0102] With the preceding medium M1 and the following medium M2 still overlapping, the leading edge of the following medium M2 passes through the first curved portion 24. In this case, the leading edge of the following medium M2 is guided by the preceding medium M1. Therefore, the risk of the leading edge of the following medium M2 rubbing violently against the first curved portion 24 is reduced.

[0103] As shown in FIG. 15, when the preceding medium M1 is transported, the trailing end of the preceding medium M1 passes the registration rollers 44. At this time, the control unit 65 stops the registration rollers 44. This allows the registration rollers 44 to correct the skew of the following medium M2 while continuing to transport the preceding medium M1. In order to correct the skew of the following medium M2, the trailing end of the preceding medium M1 must pass the registration rollers 44 before the leading end of the following medium M2 reaches the registration rollers 44. In one example, when the trailing end of the preceding medium M1 passes the registration rollers 44, the leading end of the following medium M2 is positioned at the first curved portion 24.

[0104] The control unit 65 rotates the first transport roller 37, the second transport roller 38, and the third transport roller 39 to transport the following medium M2, whose leading edge is located in the first curved portion 24, at a first speed. This suppresses the generation of paper dust, static electricity, and the like on the following medium M2.

[0105] 16, the control unit 65 turns off the transport clutch when the leading edge of the following medium M2 reaches the registration roller 44. Specifically, after correcting the skew of the following medium M2, the control unit 65 turns off the first transport clutch 41, the second transport clutch 42, and the third transport clutch 43. The control unit 65 rotates the registration roller 44 so as to transport the following medium M2 at the second speed.

[0106] <Flowchart> Next, the transport process executed by the control unit 65 will be described. The transport process is a process in which media 99 are transported while overlapping each other. The transport process is started when a user instruction is input. The control unit 65 starts the transport process by, for example, selecting the first mode. The following explanation also uses an example in which two media 99 are transported consecutively, but it goes without saying that the process can also be applied to cases in which three or more media 99 are transported.

[0107] Regarding the transport process, a first transport process and a second transport process will be described. The first transport process is a process for transporting the medium 99 according to the first pattern described above. The second transport process is a process for transporting the medium 99 according to the second pattern described above.

[0108] First, the first transport process will be described. As shown in Fig. 17, the control unit 65 starts the overlapping formation process in step S11. The overlapping formation process is a process for overlapping media 99. The control unit 65 feeds the media 99 while overlapping them through the overlapping formation process. The control unit 65 starts the overlapping formation process in accordance with the flowchart shown in Fig. 18.

[0109] 18, the control unit 65 resets the timer in step S31. Specifically, the control unit 65 resets the time that it itself counts. In step S32, the control unit 65 drives the feed motor 33. More specifically, the control unit 65 drives the feed motor 33 so that the feed roller 32 feeds the medium 99 at a first speed. At this time, the feed clutch 34 is OFF, so the feed roller 32 does not rotate. In other words, no feed force is applied from the feed roller 32 to the medium 99.

[0110] In step S33, the control unit 65 drives the transport motor 40. More specifically, the control unit 65 drives the transport motor 40 so that the transport rollers transport the medium 99 at a first speed. The control unit 65 drives the transport motor 40 so that the first transport roller 37, the second transport roller 38, and the third transport roller 39 transport the medium 99 at the first speed. At this time, the first transport clutch 41, the second transport clutch 42, and the third transport clutch 43 are OFF, so the first transport roller 37, the second transport roller 38, and the third transport roller 39 do not rotate. In other words, no transport force is applied to the medium 99 from the transport rollers.

[0111] In step S34, the control unit 65 turns on the conveying clutches. Specifically, the control unit 65 turns on the first conveying clutch 41, the second conveying clutch 42, and the third conveying clutch 43. This causes the first conveying roller 37, the second conveying roller 38, and the third conveying roller 39 to rotate.

[0112] In step S35, the control unit 65 starts a timer. That is, the control unit 65 starts counting time. The control unit 65 counts the time that has elapsed since the feeding of the medium 99 started.

[0113] In step S36, the control unit 65 turns on the feed clutch 34. This rotates the feed roller 32. The preceding medium M1 is fed by the rotation of the feed roller 32. This puts the recording device 11 in the state shown in FIG.

[0114] In step S37, the control unit 65 determines whether time t1 has elapsed. Specifically, the control unit 65 determines whether time t1 has elapsed since step S35. Time t1 may be a time pre-stored in the control unit 65 or may be a time calculated by the control unit 65. Time t1 is the time at which the leading edge of the medium 99 fed in step S36 is expected to reach the third transport roller 39. That is, in step S37, the control unit 65 determines whether the preceding medium M1 has reached the third transport roller 39. If time t1 has elapsed, the control unit 65 proceeds to step S38. If time t1 has not elapsed, the control unit 65 repeats the process of step S37. The control unit 65 may determine whether the preceding medium M1 has reached the third transport roller 39 based on the detection result of a sensor, regardless of the passage of time.

[0115] In step S38, the control unit 65 turns off the feed clutch 34. This causes the feed roller 32 to rotate in response to the preceding medium M1. That is, the feed roller 32 enters a state in which it does not apply a feed force to the preceding medium M1.

[0116] In step S39, the control unit 65 determines whether time t2 has elapsed. More specifically, the control unit 65 determines whether time t2 has elapsed since step S35. Time t2 may be a time pre-stored in the control unit 65, or may be a time calculated by the control unit 65. Time t2 is a time for determining the feed timing of the subsequent medium M2. Time t2 is a time for determining the amount of overlap between the preceding medium M1 and the subsequent medium M2. If time t2 has elapsed, the control unit 65 proceeds to step S40. If time t2 has not elapsed, the control unit 65 repeats the processing of step S39.

[0117] In step S40, the control unit 65 turns on the feed clutch 34. This causes the feed roller 32 to rotate. The rotation of the feed roller 32 causes the subsequent medium M2 to be fed. That is, the subsequent medium M2 is fed in a state where it overlaps the preceding medium M1. This places the recording device 11 in the state shown in FIG. 4. When the control unit 65 completes the processing of step S40, it ends the overlap formation processing. When the control unit 65 completes the overlap formation processing, it returns to the transport processing.

[0118] 17, in step S12, the control unit 65 determines whether the first detection sensor 56 has turned ON. That is, the control unit 65 determines whether the preceding medium M1 has reached the registration rollers 44. The control unit 65 may determine whether the preceding medium M1 has reached the registration rollers 44 based on the passage of time, not limited to the detection result of the first detection sensor 56. If the first detection sensor 56 has turned ON, the control unit 65 proceeds to step S13. If the first detection sensor 56 is OFF, the control unit 65 repeats the process of step S12.

[0119] In step S13, the control unit 65 determines whether the waiting time has elapsed. More specifically, the control unit 65 determines whether the waiting time has elapsed since step S12. The waiting time is the time required to correct skew. That is, in step S13, the leading edge of the preceding medium M1 is abutted against the registration roller 44, thereby correcting skew of the preceding medium M1. If the waiting time has elapsed, the control unit 65 proceeds to step S14. If the waiting time has not elapsed, the control unit 65 repeats the processing of step S13.

[0120] In step S14, the control unit 65 turns off the transport clutches. More specifically, the control unit 65 turns off the first transport clutch 41, the second transport clutch 42, and the third transport clutch 43. This causes the transport rollers to rotate in response to the preceding medium M1. In other words, the transport rollers are in a state where they do not apply a transport force to the preceding medium M1. At this time, the recording device 11 is in the state shown in FIG. 5. Note that it is sufficient to turn off the transport clutches of the transport rollers where the preceding medium M1 is located; if there are transport rollers that the preceding medium M1 has passed through, it is not necessary to turn off the transport clutches of those transport rollers.

[0121] In step S15, the control unit 65 drives the registration rollers 44. Specifically, the control unit 65 rotates the registration rollers 44 so as to transport the preceding medium M1 at the second speed.

[0122] In step S16, the control unit 65 determines whether time t3 has elapsed. Specifically, the control unit 65 determines whether time t3 has elapsed since step S35. Time t3 is the time when the rear end of the preceding medium M1 is expected to pass the third transport roller 39. That is, in step S16, the control unit 65 determines whether the preceding medium M1 has passed the third transport roller 39. If time t3 has elapsed, the control unit 65 proceeds to step S17. If time t3 has not elapsed, the control unit 65 repeats the process of step S16. The control unit 65 may determine whether the preceding medium M1 has passed the third transport roller 39 based on the detection result of a sensor, regardless of the passage of time.

[0123] In step S17, the control unit 65 turns on the third transport clutch 43. This causes the third transport roller 39 to rotate. The rotation of the third transport roller 39 causes the subsequent medium M2 to be transported at the first speed. At this time, the recording device 11 is in the state shown in FIG. 6. The control unit 65 may also turn off the feed clutch 34.

[0124] In step S18, the control unit 65 determines whether time t4 has elapsed. Specifically, the control unit 65 determines whether time t4 has elapsed since step S35. Time t4 is the time when the rear end of the preceding medium M1 is expected to pass the second transport roller 38. That is, in step S18, the control unit 65 determines whether the preceding medium M1 has passed the second transport roller 38. If time t4 has elapsed, the control unit 65 proceeds to step S19. If time t4 has not elapsed, the control unit 65 repeats the process of step S18. The control unit 65 may determine whether the preceding medium M1 has passed the second transport roller 38 based on the detection result of a sensor, regardless of the passage of time.

[0125] In step S19, the control unit 65 turns on the second transport clutch 42. This causes the second transport roller 38 to rotate. The rotation of the second transport roller 38 causes the subsequent medium M2 to be transported at the first speed. At this time, the recording device 11 is in the state shown in FIG. 7.

[0126] In step S20, the control unit 65 determines whether time t5 has elapsed. Specifically, the control unit 65 determines whether time t5 has elapsed since step S35. Time t5 is the time when the rear end of the preceding medium M1 is expected to pass the first transport roller 37. That is, in step S20, the control unit 65 determines whether the preceding medium M1 has passed the first transport roller 37. If time t5 has elapsed, the control unit 65 proceeds to step S21. If time t5 has not elapsed, the control unit 65 repeats the process of step S20. The control unit 65 may determine whether the preceding medium M1 has passed the first transport roller 37 based on the detection result of a sensor, regardless of the passage of time.

[0127] In step S21, the control unit 65 turns on the first transport clutch 41. This causes the first transport roller 37 to rotate. The rotation of the first transport roller 37 causes the subsequent medium M2 to be transported at a first speed. At this time, the recording device 11 is in the state shown in FIG. 8.

[0128] In step S22, the control unit 65 determines whether the second detection sensor 57 has turned OFF. That is, the control unit 65 determines whether the preceding medium M1 has passed the registration rollers 44. The control unit 65 may determine whether the preceding medium M1 has passed the registration rollers 44 based on the passage of time, not limited to the detection result of the second detection sensor 57. If the second detection sensor 57 has turned OFF, the control unit 65 proceeds to step S23. If the second detection sensor 57 is ON, the control unit 65 repeats the processing of step S22.

[0129] In step S23, the control unit 65 stops the registration rollers 44. By stopping the registration rollers 44, the control unit 65 completes preparations to correct skew of the subsequent medium M2. At this time, the recording device 11 is in the state shown in FIG. 9. The preceding medium M1 is transported by the transport belt 17, the discharge unit 51, etc.

[0130] In step S24, the control unit 65 determines whether the first detection sensor 56 has turned ON. That is, the control unit 65 determines whether the subsequent medium M2 has reached the registration rollers 44. The control unit 65 may determine whether the subsequent medium M2 has reached the registration rollers 44 based on the passage of time, not limited to the detection result of the first detection sensor 56. If the first detection sensor 56 has turned ON, the control unit 65 proceeds to step S25. If the first detection sensor 56 is OFF, the control unit 65 repeats the process of step S24.

[0131] In step S25, the control unit 65 determines whether the waiting time has elapsed. Specifically, the control unit 65 determines whether the waiting time has elapsed since step S24. The waiting time is the same as that in step S13. That is, in step S25, the leading edge of the subsequent medium M2 is abutted against the registration roller 44, thereby correcting skew of the subsequent medium M2. If the waiting time has elapsed, the control unit 65 proceeds to step S26. If the waiting time has not elapsed, the control unit 65 repeats the processing of step S25.

[0132] In step S26, the control unit 65 drives the registration rollers 44. More specifically, the control unit 65 rotates the registration rollers 44 so as to transport the subsequent medium M2 at the second speed. At this time, the recording device 11 is in the state shown in FIG.

[0133] In step S27, the control unit 65 determines whether the second detection sensor 57 has turned OFF. That is, the control unit 65 determines whether the subsequent medium M2 has passed the registration rollers 44. The control unit 65 may determine whether the subsequent medium M2 has passed the registration rollers 44 based on the passage of time, not limited to the detection result of the second detection sensor 57. If the second detection sensor 57 has turned OFF, the control unit 65 proceeds to step S28. If the second detection sensor 57 is ON, the control unit 65 repeats the processing of step S27.

[0134] In step S28, the control unit 65 stops the registration rollers 44. The subsequent medium M2 is transported by the transport belt 17, the discharge unit 51, etc. After completing the process of step S28, the control unit 65 ends the first transport process.

[0135] As described above, in the first conveying process, the control method of medium conveying device 16 includes rotating the conveying rollers so as to convey medium 99, whose leading edge is located on conveying path 23, at a first speed. The control method of medium conveying device 16 also includes rotating registration roller 44 so as to convey medium 99, whose leading edge has reached registration roller 44, at a second speed. The control method of medium conveying device 16 also includes rotating feed roller 32 so that subsequent medium M2 overlaps preceding medium M1 until the leading edge of preceding medium M1 reaches registration roller 44.

[0136] Next, the second transport process will be described. 19, the control unit 65 starts the overlap formation process in step S51. The process of step S51 is the same as the process of step S11. The control unit 65 starts the overlap formation process in accordance with the flowchart shown in FIG.

[0137] In step S52, the control unit 65 determines whether the first detection sensor 56 is ON. Step S52 is the same process as step S12. That is, the control unit 65 determines whether the preceding medium M1 has reached the registration rollers 44. If the first detection sensor 56 is ON, the control unit 65 proceeds to step S53. If the first detection sensor 56 is OFF, the control unit 65 repeats the process of step S52.

[0138] In step S53, the control unit 65 determines whether the waiting time has elapsed. Specifically, the control unit 65 determines whether the waiting time has elapsed since step S52. The processing of step S53 is the same as the processing of step S13. That is, in step S53, the leading edge of the preceding medium M1 is abutted against the registration roller 44, thereby correcting skew of the preceding medium M1. If the waiting time has elapsed, the control unit 65 proceeds to step S54. If the waiting time has not elapsed, the control unit 65 repeats the processing of step S53.

[0139] In step S54, the control unit 65 turns off the feed clutch 34. This causes the feed roller 32 to rotate in response to the following medium M2. That is, the feed roller 32 enters a state in which it does not apply a feed force to the following medium M2.

[0140] In step S55, the control unit 65 switches the transport rollers to the second speed. More specifically, the control unit 65 rotates the transport rollers so as to transport the preceding medium M1 at the second speed. The control unit 65 controls the transport motor 40 to rotate the first transport roller 37, the second transport roller 38, and the third transport roller 39 so as to transport the preceding medium M1 at the second speed. As the preceding medium M1 is transported at the second speed, the following medium M2 is also transported at the second speed. At this time, the recording device 11 is in the state shown in FIG. 11.

[0141] In step S56, the control unit 65 drives the registration rollers 44. Specifically, the control unit 65 rotates the registration rollers 44 so as to transport the preceding medium M1 at the second speed.

[0142] In step S57, the control unit 65 determines whether time t6 has elapsed. More specifically, it determines whether time t6 has elapsed since step S35. Time t6 is the time when the rear end of the preceding medium M1 is expected to have passed the first transport roller 37. That is, in step S57, the control unit 65 determines whether the preceding medium M1 has passed the first transport roller 37. If time t6 has elapsed, the control unit 65 proceeds to step S58. If time t6 has not elapsed, the control unit 65 repeats the process of step S57. The control unit 65 may determine whether the preceding medium M1 has passed the first transport roller 37 based on the detection result of a sensor, regardless of the passage of time.

[0143] In step S58, the control unit 65 switches the transport rollers to the first speed. Specifically, the control unit 65 rotates the transport rollers so as to transport the following medium M2 at the first speed. The control unit 65 controls the transport motor 40 to rotate the first transport roller 37, the second transport roller 38, and the third transport roller 39 so as to transport the following medium M2 at the first speed. As a result, the preceding medium M1 is transported at the first speed, while the following medium M2 is transported at the first speed. At this time, the recording device 11 is in the state shown in FIG. 14.

[0144] In step S59, the control unit 65 determines whether the second detection sensor 57 has turned OFF. The control unit 65 determines whether the preceding medium M1 has passed the registration rollers 44. The control unit 65 may determine whether the preceding medium M1 has passed the registration rollers 44 based on the passage of time, not limited to the detection result of the second detection sensor 57. If the second detection sensor 57 has turned OFF, the control unit 65 proceeds to step S60. If the second detection sensor 57 is ON, the control unit 65 repeats the processing of step S59.

[0145] In step S60, the control unit 65 stops the registration rollers 44. By stopping the registration rollers 44, the control unit 65 completes preparations to correct skew of the subsequent medium M2. At this time, the recording device 11 is in the state shown in FIG. 15. The preceding medium M1 is transported by the transport belt 17, the discharge unit 51, etc.

[0146] In step S61, the control unit 65 determines whether the first detection sensor 56 has turned ON. The control unit 65 determines whether the subsequent medium M2 has reached the registration rollers 44. The control unit 65 may determine whether the subsequent medium M2 has reached the registration rollers 44 based on the passage of time, not limited to the detection result of the first detection sensor 56. If the first detection sensor 56 has turned ON, the control unit 65 proceeds to step S62. If the first detection sensor 56 is OFF, the control unit 65 repeats the processing of step S61.

[0147] In step S62, the control unit 65 determines whether the waiting time has elapsed. More specifically, the control unit 65 determines whether the waiting time has elapsed since step S61. In step S62, the leading edge of the subsequent medium M2 is abutted against the registration roller 44, thereby correcting the skew of the subsequent medium M2. At this time, the recording device 11 is in the state shown in FIG. 16. If the waiting time has elapsed, the control unit 65 proceeds to step S63. If the waiting time has not elapsed, the control unit 65 repeats the processing of step S62.

[0148] In step S63, the control unit 65 drives the registration rollers 44. Specifically, the control unit 65 drives the registration rollers 44 to transport the subsequent medium M2 at the second speed. At this time, the control unit 65 may switch the transport rollers to the second speed as in step S55, or may turn off the transport clutch as in step S14.

[0149] In step S64, the control unit 65 determines whether the second detection sensor 57 has turned OFF. That is, the control unit 65 determines whether the subsequent medium M2 has passed the registration rollers 44. The control unit 65 may determine whether the subsequent medium M2 has passed the registration rollers 44 based on the passage of time, not limited to the detection result of the second detection sensor 57. If the second detection sensor 57 has turned OFF, the control unit 65 proceeds to step S65. If the second detection sensor 57 is ON, the control unit 65 repeats the processing of step S64.

[0150] In step S65, the control unit 65 stops the registration rollers 44. The subsequent medium M2 is transported by the transport belt 17, the discharge unit 51, etc. After completing the process of step S65, the control unit 65 ends the second transport process.

[0151] As described above, in the second conveying process, the control method of the medium conveying device 16 includes rotating the conveyance rollers so as to convey the medium 99 whose leading edge is located in the first curved portion 24 at a first speed. The control method of the medium conveying device 16 includes rotating the conveyance rollers so as to convey the medium 99 whose leading edge is located in the upstream portion 26 at a second speed. The control method of the medium conveying device 16 includes rotating the registration rollers 44 so as to convey the medium 99 whose leading edge has reached the registration rollers 44 at the second speed. The control method of the medium conveying device 16 includes rotating the feed rollers 32 so that the following medium M2 overlaps the preceding medium M1 until the leading edge of the preceding medium M1 reaches the registration rollers 44.

[0152] <Actions and Effects of the Example> Next, the operation and effects of the above embodiment will be described. (1) The control unit 65 rotates the transport rollers to transport the medium 99 at a first speed. The control unit 65 rotates the registration rollers 44 to transport the medium 99 at a second speed. The control unit 65 rotates the feed rollers 32 so that the following medium M2 overlaps the preceding medium M1 until the leading edge of the preceding medium M1 reaches the registration rollers 44. According to the above configuration, the medium 99 whose leading edge is located in the first curved portion 24 is transported by the transport rollers at the relatively slow first speed. This reduces the risk of paper dust being generated from the medium 99 or the medium 99 becoming electrostatically charged. By having the feed rollers 32 feed the medium 99 so that the following medium M2 overlaps the preceding medium M1, a decrease in processing speed is suppressed.

[0153] (2) The control unit 65 rotates the transport rollers so as to transport the medium 99, whose leading edge is located on the transport path 23, at a first speed. According to the above configuration, the medium 99, whose leading edge is located on the transport path 23, is transported by the transport rollers at the relatively slow first speed. This reduces the risk of paper dust being generated from the medium 99 or the medium 99 becoming electrically charged.

[0154] (3) When the leading edge of the medium 99 reaches the registration rollers 44, the control unit 65 switches the transport rollers to a state in which they do not apply a transport force to the medium 99. The medium 99 whose leading edge has reached the registration rollers 44 is transported by the registration rollers 44 at a relatively high second speed. At this time, no transport force is applied from the transport rollers to the medium 99 whose leading edge has reached the registration rollers 44. Therefore, with the above configuration, the risk of the medium 99 whose leading edge has reached the registration rollers 44 being strained by the registration rollers 44 and the transport rollers is reduced.

[0155] (4) The control unit 65 rotates the feed roller 32 so that the overlap between the preceding medium M1 and the following medium M2 is resolved before the leading edge of the following medium M2 reaches the registration roller 44. According to the above configuration, the preceding medium M1 passes through the registration roller 44 before the following medium M2 reaches the registration roller 44. Therefore, after the preceding medium M1 passes through the registration roller 44, the following medium M2 hits the registration roller 44. This smoothly corrects the skew of the following medium M2.

[0156] (5) After the preceding medium M1 has passed the second transport roller 38, the control unit 65 rotates the second transport roller 38 to transport the following medium M2 at the first speed. According to the above configuration, the following medium M2 can be transported by the second transport roller 38 while reducing the risk of the preceding medium M1 being pushed up by the registration roller 44 and the second transport roller 38.

[0157] (6) The control unit 65 rotates the transport roller to transport the medium 99 whose leading edge is located in the first curved portion 24 at a first speed. The control unit 65 rotates the transport roller to transport the medium 99 whose leading edge is located in the upstream portion 26 at a second speed. According to the above configuration, the medium 99 whose leading edge is located in the first curved portion 24 is transported by the transport roller at a relatively slow first speed. This reduces the risk of paper dust being generated from the medium 99 or the medium 99 becoming electrically charged. The medium 99 whose leading edge is located in the upstream portion 26 is transported by the transport roller at a relatively fast second speed. This more effectively prevents a decrease in processing speed.

[0158] (7) The control unit 65 rotates the feed roller 32 so that the overlap between the preceding medium M1 and the following medium M2 is resolved before the leading edge of the following medium M2 reaches the registration roller 44. According to the above configuration, the preceding medium M1 passes through the registration roller 44 before the following medium M2 reaches the registration roller 44. Therefore, after the preceding medium M1 passes through the registration roller 44, the following medium M2 can abut against the registration roller 44. This allows the skew of the following medium M2 to be smoothly corrected.

[0159] (8) The control unit 65 rotates the transport rollers to transport the preceding medium M1 and the following medium M2 at the second speed until the preceding medium M1 passes the transport rollers. According to the above configuration, in the upstream section 26, the medium 99 is transported by the transport rollers at the relatively high second speed. This more effectively prevents a decrease in processing speed.

[0160] (9) After the preceding medium M1 has passed the transport rollers, the control unit 65 rotates the transport rollers to transport the following medium M2 at a first speed. With the above configuration, the following medium M2 can be transported by the transport rollers while reducing the risk of the preceding medium M1 being pushed up by the registration rollers 44 and the transport rollers.

[0161] (10) The control unit 65 rotates the feed roller 32 so as to feed the medium 99, whose leading edge is located in the second curved portion 25, at a first speed. According to the above configuration, the medium 99, whose leading edge is located in the second curved portion 25, is fed by the feed roller 32 at the relatively slow first speed. This reduces the risk of paper dust being generated from the medium 99 or the medium 99 becoming electrically charged.

[0162] (11) The control unit 65 rotates the feed roller 32 to feed the medium 99 at a first speed. This configuration reduces the risk of paper dust being generated from the medium 99 or the medium 99 becoming electrically charged.

[0163] (12) The control unit 65 determines the amount of overlap between the preceding medium M1 and the succeeding medium M2 based on the information acquired by the acquisition unit 61. Depending on the length of the medium 99, the transport method, etc., the first speed or the second speed may change. When the first speed, second speed, etc. change, it is necessary to change the amount of overlap between the preceding medium M1 and the succeeding medium M2. With the above configuration, an appropriate amount of overlap is determined based on information regarding the transport of the medium 99. This allows the processing speed to be maintained based on information regarding the transport of the medium 99.

[0164] (13) The control unit 65 selects the first mode or the second mode based on the information acquired by the acquisition unit 61. According to the above configuration, the second mode allows the preceding medium M1 and the following medium M2 to be transported without overlapping each other.

[0165] (14) The medium transport device 16 continuously transports the medium 99 during recording. According to the above configuration, the overlap between the preceding medium M1 and the following medium M2 is resolved before the leading edge of the following medium M2 reaches the registration roller 44, so that the registration roller 44 can correct the skew of the following medium M2.

[0166] (15) The conveyor belt 17 is located downstream of the registration rollers 44. According to the above configuration, the conveyor belt 17 adheres to the medium 99 that has passed through the registration rollers 44. This stabilizes the position of the medium 99.

[0167] <Example of change> The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined with each other within the scope of technical compatibility.

[0168] The medium conveying device 16 may be applied to an image reading device that reads an image of the medium 99. The image reading device is, for example, a scanner or an automatic document reader (ADF). In this case, the acquisition unit 61 may acquire the reading method of the medium 99 as information related to the conveyance of the medium 99. The control unit 65 may determine the overlap amount of the medium 99 based on the reading method of the medium 99.

[0169] The transport unit 36 ​​may have another roller located upstream of the registration rollers 44. The control unit 65 may use this roller as a reference to change the transport speed of the medium 99 or eliminate the amount of overlap.

[0170] The liquid ejected by the recording unit 13 is not limited to ink, but may be a liquid in which particles of a functional material are dispersed or mixed in a liquid. For example, the recording unit 13 may eject a liquid containing, in a dispersed or dissolved form, a material such as an electrode material or a pixel material used in the manufacture of liquid crystal displays, electroluminescent displays, and surface-emitting displays.

[0171] As long as the speed can be appropriately changed, at least some of the feed motor 33, the transport motor 40, and the registration motor 45 may be a common motor. The acquisition sensor 62 is not limited to an optical sensor, but may be a mechanical sensor, an ultrasonic sensor, etc. Also, a combination of multiple sensors may be used.

[0172] When determining the overlap amount based on information related to transportation, the control unit 65 may calculate the overlap amount based on the information, or the control unit 65 may select the overlap amount based on a predetermined relationship between the information and the overlap amount.

[0173] <Technical philosophy> The technical concepts and effects that can be understood from the above-described embodiment and modified examples will be described below.

[0174] (A) A medium transport device includes a feed roller that feeds a medium, a transport roller that transports the medium fed by the feed roller, a registration roller that corrects skew of the medium transported by the transport roller, a transport path extending from the feed roller toward the registration roller, and a control unit that rotates the transport roller to transport the medium at a first speed and rotates the registration roller to transport the medium at a second speed higher than the first speed, where the transport path has a curved portion that extends while curving between the transport roller and the registration roller, and the control unit rotates the feed roller so that a subsequent medium fed after the preceding medium overlaps the preceding medium until the leading edge of the preceding medium reaches the registration roller. According to the above configuration, a medium whose leading edge is located in the curved portion is transported by the transport roller at a relatively slow first speed. This reduces the risk of paper dust generation from the medium or electrostatic charging of the medium. By the feed roller feeding the medium so that the subsequent medium overlaps the preceding medium, a decrease in processing speed is suppressed. Furthermore, it is sufficient that the trailing medium overlaps the preceding medium at least until the leading edge of the preceding medium reaches the registration roller, and the trailing medium may also overlap the preceding medium even after the leading edge of the preceding medium reaches the registration roller.

[0175] (B) In the above-described medium transport device, the control unit may rotate the transport roller so as to transport the medium whose leading edge is located in the transport path at the first speed. According to the above configuration, the medium whose leading edge is located in the transport path is transported by the transport roller at the relatively slow first speed. This reduces the risk of paper dust being generated from the medium or the medium becoming electrically charged.

[0176] (C) In the above-described medium conveying device, the control unit may switch the conveying roller to a state in which it does not apply a conveying force to the medium when the leading edge of the medium reaches the registration roller. The medium whose leading edge has reached the registration roller is conveyed by the registration roller at a relatively high second speed. At this time, no conveying force is applied from the conveying roller to the medium whose leading edge has reached the registration roller. Therefore, with the above configuration, the risk of the medium whose leading edge has reached the registration roller being strained by the registration roller and the conveying roller is reduced.

[0177] (D) In ​​the above-described medium conveying device, the control unit may rotate the feed roller so that the overlap between the preceding medium and the following medium is resolved before the leading edge of the following medium reaches the registration roller. According to the above configuration, the preceding medium passes through the registration roller before the following medium reaches the registration roller. Therefore, after the preceding medium passes through the registration roller, the following medium strikes the registration roller. This allows for smooth correction of skew in the following medium.

[0178] (E) In the above-described medium transport device, the transport roller may be a first transport roller, and the medium transport device may include a second transport roller located upstream of the first transport roller, and the control unit may rotate the second transport roller so as to transport the following medium at the first speed after the preceding medium has passed the second transport roller. According to the above configuration, the following medium can be transported by the second transport roller while reducing the risk of the preceding medium being tensed by the registration roller and the second transport roller. The risk of the preceding medium being tensed by the first transport roller is reduced when transported at the second speed.

[0179] (F) In the above-described medium transport device, the transport path may include an upstream portion located upstream of the curved portion, the upstream portion having a smaller curvature than the curved portion, and the control unit may rotate the transport roller to transport the medium whose leading edge is located in the curved portion at the first speed, and rotate the transport roller to transport the medium whose leading edge is located in the upstream portion at the second speed. According to the above configuration, the medium whose leading edge is located in the curved portion is transported by the transport roller at the relatively slow first speed. This reduces the risk of paper dust being generated from the medium or the medium becoming electrostatically charged. The medium whose leading edge is located in the upstream portion is transported by the transport roller at the relatively fast second speed. This prevents a decrease in processing speed.

[0180] (G) In the above-described medium transport device, the control unit may rotate the feed roller so that the overlap between the preceding medium and the following medium is eliminated before the leading edge of the following medium reaches the registration roller. According to the above configuration, the preceding medium passes through the registration roller before the following medium reaches the registration roller. Therefore, the following medium can strike the registration roller after the preceding medium has passed the registration roller. This allows for smooth correction of skew in the following medium.

[0181] (H) In the above-described medium transport device, the curved portion may be located between the upstream portion and the registration roller, the transport roller may be located in the upstream portion, and the control unit may rotate the transport roller to transport the preceding medium and the following medium at the second speed until the preceding medium passes the transport roller. According to the above configuration, in the upstream portion, the medium is transported by the transport roller at the relatively high second speed. This prevents a decrease in processing speed.

[0182] (I) In the medium transport device, the control unit may rotate the transport roller so as to transport the following medium at a first speed after the preceding medium has passed the transport roller. With the above configuration, the following medium can be transported by the transport roller while reducing the risk of the preceding medium being strained by the registration roller and the transport roller.

[0183] (J) In the above-described medium transport device, the curved portion may be a first curved portion, the transport path may include a second curved portion located upstream of the upstream portion, the second curved portion having a larger curvature than the upstream portion, the feed roller may feed the medium along the second curved portion, and the control unit may rotate the feed roller so as to feed the medium whose leading edge is located in the second curved portion at the first speed. According to the above configuration, the medium whose leading edge is located in the second curved portion is fed by the feed roller at the relatively slow first speed. This reduces the risk of paper dust being generated from the medium or the medium becoming electrostatically charged.

[0184] (K) In the medium transport device, the control unit may rotate the feed roller so as to feed the medium at the first speed. This configuration reduces the risk of paper dust being generated from the medium or the medium becoming electrically charged.

[0185] (L) The medium transport device may include an acquisition unit that acquires information related to medium transport, and the control unit may determine the amount of overlap between the preceding medium and the succeeding medium based on the information acquired by the acquisition unit. Depending on the length of the medium, the transport method, etc., the first speed or the second speed may change. When the first speed, second speed, etc. change, it is necessary to change the amount of overlap between the preceding medium and the succeeding medium. According to the above configuration, an appropriate amount of overlap is determined based on information related to medium transport. This allows the processing speed to be maintained based on information related to medium transport.

[0186] (M) The medium transport device may include an acquisition unit that acquires information related to medium transport, and the control unit may select, based on the information acquired by the acquisition unit, a first mode in which the feed roller is rotated so that the preceding medium and the following medium overlap, or a second mode in which the feed roller is rotated so that the preceding medium and the following medium do not overlap. According to the above configuration, the second mode can also be used to transport the preceding medium and the following medium without overlapping them.

[0187] (N) A recording device includes the medium transport device and a recording unit that records an image on the medium transported by the medium transport device, and the medium transport device continuously transports the medium being recorded by the recording unit. With the above configuration, the overlap between the preceding medium and the following medium is eliminated before the leading edge of the following medium reaches the registration roller, so that the registration roller can correct the skew of the following medium.

[0188] (O) In the above recording device, the medium transport device may include a transport belt that faces the recording unit and transports the medium to be recorded by the recording unit while adsorbing the medium, the transport belt being located downstream of the registration roller. According to the above configuration, the transport belt adsorbs the medium that has passed through the registration roller, thereby stabilizing the position of the medium.

[0189] (P) A recording device includes the medium transport device and a recording unit that records an image on the medium transported by the medium transport device. According to the above configuration, a decrease in processing speed is suppressed in the recording device.

[0190] (Q) A control method for a medium transport device includes a feed roller that feeds a medium, a transport roller that transports the medium fed by the feed roller, a registration roller that corrects skew of the medium transported by the transport roller, and a transport path extending from the feed roller toward the registration roller, the transport path including a curved portion extending while curving between the transport roller and the registration roller. The control method includes rotating the transport roller to transport a medium whose leading edge is located in the transport path at a first speed, rotating the registration roller to transport a medium whose leading edge has reached the registration roller at a second speed greater than the first speed, and rotating the feed roller so that a subsequent medium fed after the leading medium overlaps the leading medium until the leading edge of the preceding medium reaches the registration roller. According to the above method, the medium whose leading edge is located in the transport path is transported by the transport roller at a relatively slow first speed. This reduces the risk of paper dust being generated from the medium or the medium becoming electrically charged. The feed roller feeds the medium so that the succeeding medium overlaps the preceding medium, thereby preventing a decrease in processing speed.

[0191] (R) A control method for a media transport device includes a feed roller that feeds a medium, a transport roller that transports the medium fed by the feed roller, a registration roller that corrects skew of the medium transported by the transport roller, and a transport path extending from the feed roller toward the registration roller, wherein the transport path includes a curved portion that extends while curving between the transport roller and the registration roller, and an upstream portion that is located upstream of the curved portion and has a smaller curvature than the curved portion, and includes rotating the transport roller to transport a medium whose leading edge is located in the curved portion at a first speed, rotating the transport roller to transport a medium whose leading edge is located in the upstream portion at a second speed that is greater than the first speed, rotating the registration roller to transport a medium whose leading edge has reached the registration roller at the second speed, and rotating the feed roller so that a subsequent medium fed after the leading medium overlaps the leading medium until the leading edge of the leading medium reaches the registration roller. According to the above method, when the leading edge of a medium is positioned in a curved portion, the medium is transported by the transport roller at a relatively slow first speed. This reduces the risk of paper dust generation or electrostatic charge on the medium. The feed roller feeds the medium so that the following medium overlaps the preceding medium, thereby preventing a decrease in processing speed. [Explanation of symbols]

[0192] 11...recording device, 12...casing, 13...recording unit, 14...operation unit, 15...control terminal, 16...medium conveying device, 17...conveyor belt, 18...first pulley, 19...second pulley, 21...loading unit, 23...conveying path, 24...first curved portion, 25...second curved portion, 26...upstream portion, 27...connecting portion, 28...discharge path, 29...re-conveying path, 31...feeding unit, 32...feeding roller, 33...feeding motor, 34...feeding clutch, 36...conveying unit, 37...first conveying roller, 38...second conveying roller, 39...third conveying roller, 40... Conveying motor, 41...first conveying clutch, 42...second conveying clutch, 43...third conveying clutch, 44...registration roller, 45...registration motor, 46...first driven roller, 47...second driven roller, 48...third driven roller, 49...fourth driven roller, 51...discharge section, 52...discharge roller, 53...sub-roller, 55...detection section, 56...first detection sensor, 57...second detection sensor, 61...acquisition section, 62...acquisition sensor, 63...connection body, 65...control section, 99...medium, M1...preceding medium, M2...subsequent medium.

Claims

1. a feed roller for feeding the medium; a transport roller that transports the medium fed by the feed roller; a registration roller that corrects skew of the medium transported by the transport roller; a conveyance path extending from the feed roller toward the registration roller; a control unit that rotates the transport roller to transport the medium at a first speed and rotates the registration roller to transport the medium at a second speed that is higher than the first speed, the conveying path has a curved portion that extends while curving between the conveying roller and the registration roller, The control unit is characterized in that it rotates the feed roller so that the subsequent medium fed after the preceding medium overlaps the preceding medium until the leading edge of the preceding medium reaches the registration roller.

2. The medium transport device according to claim 1 , wherein the control unit rotates the transport roller so as to transport the medium, the leading edge of which is positioned in the transport path, at the first speed.

3. 3. The medium transport device according to claim 2, wherein the control unit switches the transport roller to a state in which it does not apply a transport force to the medium when the leading edge of the medium reaches the registration roller.

4. The medium transport device according to claim 2 , wherein the control unit rotates the feed roller so that the overlap between the preceding medium and the following medium is eliminated before the leading edge of the following medium reaches the registration roller.

5. The transport roller is a first transport roller, the medium transport device includes a second transport roller located upstream of the first transport roller; The medium transport device according to claim 2 , wherein the control unit rotates the second transport roller so as to transport the subsequent medium at the first speed after the preceding medium has passed the second transport roller.

6. the conveying path includes an upstream portion located upstream of the curved portion, the upstream portion has a smaller curvature than the curved portion, The control unit rotating the transport roller so as to transport the medium, the leading edge of which is located in the curved portion, at the first speed; The medium transport device according to claim 1 , wherein the transport roller is rotated so as to transport the medium whose leading edge is located in the upstream portion at the second speed.

7. The media transport device of claim 6, wherein the control unit rotates the feed roller so that the overlap between the preceding medium and the following medium is eliminated before the leading edge of the following medium reaches the registration roller.

8. the curved portion is located between the upstream portion and the registration roller, the transport roller is located in the upstream portion, The medium transport device according to claim 6 , wherein the control unit rotates the transport roller so as to transport the preceding medium and the following medium at the second speed until the preceding medium passes the transport roller.

9. The medium transport device according to claim 8 , wherein the control unit rotates the transport roller so as to transport the following medium at a first speed after the preceding medium has passed the transport roller.

10. the curved portion is a first curved portion; the conveying path includes a second curved portion located upstream of the upstream portion, the second curved portion has a larger curvature than the upstream portion, the feed roller feeds the medium along the second curved portion; 10. The medium transport device according to claim 6, wherein the control unit rotates the feed roller so as to feed the medium, the leading edge of which is located in the second curved portion, at the first speed.

11. 10. The medium transport device according to claim 1, wherein the control unit rotates the feed roller so as to feed the medium at the first speed.

12. an acquisition unit that acquires information regarding the transportation of the medium; The medium transport device according to claim 11 , wherein the control unit determines an overlap amount between the preceding medium and the succeeding medium based on the information acquired by the acquisition unit.

13. an acquisition unit that acquires information regarding the transportation of the medium; The medium conveying device described in any one of claims 1 to 9, characterized in that the control unit selects, based on the information acquired by the acquisition unit, a first mode in which the feed roller rotates so that the preceding medium and the following medium overlap, or a second mode in which the feed roller rotates so that the preceding medium and the following medium do not overlap.

14. a medium transport device according to claim 4 or claim 7; a recording unit that records an image on the medium transported by the medium transport device, The recording apparatus is characterized in that the medium transport device continuously transports the medium being recorded by the recording unit.

15. the medium transport device includes a transport belt that faces the recording unit and transports the medium to be recorded by the recording unit while adsorbing the medium, 15. The recording apparatus according to claim 14, wherein the transport belt is located downstream of the registration roller.

16. The medium transport device according to any one of claims 1 to 9; a recording unit that records an image on the medium transported by the medium transport device.

17. A method for controlling a medium transport device comprising: a feed roller that feeds a medium; a transport roller that transports the medium fed by the feed roller; a registration roller that corrects skew of the medium transported by the transport roller; and a transport path extending from the feed roller toward the registration roller, wherein the transport path includes a curved portion that extends while curving between the transport roller and the registration roller, rotating the transport roller so as to transport the medium, the leading edge of which is located in the transport path, at a first speed; rotating the registration roller so as to transport the medium whose leading edge has reached the registration roller at a second speed that is higher than the first speed; and rotating the feed roller so that a subsequent medium fed after the preceding medium overlaps the preceding medium until the leading edge of the preceding medium reaches the registration roller.

18. A method for controlling a medium transport device comprising: a feed roller that feeds a medium; a transport roller that transports the medium fed by the feed roller; a registration roller that corrects skew of the medium transported by the transport roller; and a transport path extending from the feed roller toward the registration roller, wherein the transport path includes a curved portion that extends while curving between the transport roller and the registration roller, and an upstream portion that is located upstream of the curved portion and has a curvature smaller than that of the curved portion, rotating the transport roller so as to transport the medium whose leading edge is located in the curved portion at a first speed; rotating the transport roller to transport the medium whose leading edge is located in the upstream portion at a second speed that is greater than the first speed; rotating the registration roller so as to transport the medium whose leading edge has reached the registration roller at the second speed; and rotating the feed roller so that a subsequent medium fed after the preceding medium overlaps the preceding medium until the leading edge of the preceding medium reaches the registration roller.

Images