JP2017071480A - Recording device - Google Patents

Abstract

A paper jam occurs because the leading edge of the paper is not guided to the nip position of a pair of conveyance rollers when the paper is to be transported downstream after paper skew correction processing. Solve.
A control unit is provided that selects and executes a first skew correction processing mode or a second skew correction processing mode according to a selection condition, and transports from a time t2 when rotation of a transport driving roller stops in a positive rotation direction. The elapsed time TB in the second skew correction processing mode in the elapsed time until the tip returns to the nip position by rotating the drive roller in the reverse rotation direction and then rotating in the forward rotation direction again is the first time When it is longer than the elapsed time TA in the skew correction processing mode and the selection condition is determined that the paper is thick, the first skew correction processing mode is selected, and when it is determined that the paper is thin, the second skew correction processing is performed. A recording apparatus for selecting a mode is provided.
[Selection] Figure 10

Description

  The present invention relates to a recording apparatus.

  In a recording apparatus that records while a sheet as a recording medium is conveyed, when the sheet is fed to the recording unit in a skewed state with respect to the conveying direction, an image is recorded at the position of the target sheet. In some cases, the end portion in the direction intersecting with the sheet conveyance direction hits a member such as a wall portion and is jammed. Accordingly, processing for correcting the skew of the paper is performed by drivingly controlling a pair of conveyance rollers provided at a position upstream of the recording unit in the conveyance direction. For example, in Patent Document 1, the front end of a sheet to be fed is bitten (clamped) by a pair of transport rollers that rotate in the forward direction, and the front end of the sheet protrudes downstream, and then transported. A skew correction process is performed in which the roller pair is rotated in reverse to move the leading end of the sheet to the upstream side from the nip position of the conveying roller pair.

JP 2001-97599 A

  However, when recording on thin paper or when printing duty is high in double-sided printing, after the paper discharge process is performed by rotating the transport roller pair in the skew correction process, the transport roller pair is rotated forward again. When trying to return the leading edge of the sheet to the nip position of the conveying roller pair, the leading edge of the sheet is bent and is not guided to the nip position of the conveying roller pair, and the sheet may be jammed. In addition, if a large-size sheet is inclined, the leading edge of the end in the direction intersecting the sheet conveyance direction becomes large, and the leading edge of the sheet is not guided to the nip position of the conveyance roller pair. It tends to occur. As described above, after the paper skew correction processing is performed, when the paper is to be transported downstream, the leading edge of the paper is not guided to the nip position of the pair of transport rollers, so that the paper is jammed. There is.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  Application Example 1 When the leading end of the recording medium transported from the upstream side is sandwiched between the transport drive roller and the transport driven roller that rotate in the forward direction, the transport drive roller stops rotating in the forward rotation direction. The transport drive roller is rotated in the reverse rotation direction until the leading end is disengaged upstream from the nip position between the transport drive roller and the transport driven roller, and then the transport drive roller is rotated again in the forward rotation direction. Accordingly, a recording apparatus that performs skew correction processing of a recording medium, the recording unit disposed on the downstream side of the conveyance driving roller in the conveyance direction of the recording medium, and the rotation direction and rotation speed of the conveyance driving roller And a control unit that selects and executes the first skew correction processing mode or the second skew correction processing mode according to the selection condition. Elapsed time from when rotation of the conveyance drive roller in the forward rotation direction is stopped to when the tip is returned to the nip position by rotating the conveyance drive roller in the reverse rotation direction and then rotating in the normal rotation direction again. In time, the elapsed time in the second skew correction processing mode is longer than the elapsed time in the first skew correction processing mode, and the selection condition is that if the recording medium is thick, A recording apparatus including a condition for selecting a second skew correction processing mode when the skew correction processing mode is selected and it is determined that the recording medium is thin.

  According to this application example, after the rotation of the transport driving roller in the forward rotation direction is stopped, the transport driving roller is rotated in the reverse rotation direction, and then rotated in the forward rotation direction again, whereby the tip is In the elapsed time up to the time of returning to the nip position, the elapsed time in the second skew correction processing mode is longer than the elapsed time in the first skew correction processing mode, and the selection condition is that the recording medium is thick. Is determined, the first skew correction processing mode is selected. When it is determined that the recording medium is thin, the second skew correction processing mode is selected. As a result, when the tip of the transport drive roller and the transport driven roller that has been removed upstream from the nip position returns to the nip position again, even if the tip of the thin recording medium is bent, the bending (curvature) is small. Thus, a time for returning to a shape that can be guided to the nip position is secured. Therefore, it is possible to suppress the recording medium from being jammed in the conveyance path.

  Application Example 2 A linear feeding path in which the feeding path is formed in a linear shape, and a curved feeding path in which the feeding path is formed in a curved shape, and the selection condition further includes a recording medium Is fed by the curved feeding path, the first skew correction processing mode is selected, and when the recording medium is fed by the linear feeding path, the second skew correction processing is selected. The recording apparatus, comprising a condition for selecting a mode.

When a thin recording medium is fed by the curved feeding path, the bending direction of the tip of the recording medium may be determined on one side due to the influence of the curved shape of the curved feeding path. High, the tip is guided to the nip position. On the other hand, when a thin recording medium is fed by the linear feeding path, the bending direction of the leading end portion of the recording medium is not fixed, so there is a high possibility that it is on the other side. You may not be guided to the position.
According to this application example, when the recording medium is fed through the linear feeding path, the second skew correction processing mode is selected and executed. Thus, when the recording medium is fed by the linear feeding path, the leading end of the recording medium that has moved upstream from the nip position between the transport driving roller and the transport driven roller returns to the nip position again. In some cases, even if the leading end of the thin recording medium is bent, the bending is reduced, and a time for returning to a shape that can be guided to the nip position is secured.

  Application Example 3 The selection condition is that when the size of the recording medium is less than A4, the first skew correction processing mode is selected, and when the size of the recording medium is A4 or more, The recording apparatus including a condition for selecting the second skew correction processing mode.

  As the size of the recording medium increases, the leading end of the end of the recording medium in the direction intersecting the transport direction increases. According to this application example, when the size of the recording medium is A4 or more, the second skew correction processing mode is selected and executed. As a result, when the leading edge of the transport driving roller and the transport driven roller that has moved upstream from the nip position returns to the nip position again, even if the leading edge of the thin recording medium is bent, the bending becomes small, and the nip position Time for returning to the shape that can be guided to is secured.

  [Application Example 4] A temperature detection unit that detects temperature and a humidity detection unit that detects humidity, and the selection condition further includes: when the temperature detected by the temperature detection unit exceeds a predetermined temperature; When the humidity detected by the humidity detection unit exceeds a predetermined humidity, the second skew correction processing mode is selected, and the temperature is equal to or lower than the predetermined temperature or the humidity is equal to or lower than the predetermined humidity. The recording apparatus including a condition for selecting the first skew correction processing mode.

  According to this application example, even when the leading end of the recording medium is bent under an environmental condition that exceeds a predetermined temperature and a predetermined humidity, the bending is reduced, and the conveyance driving roller and the conveyance driven roller are Time to return to the shape that can be guided to the nip position is secured.

  Application Example 5 A reversing unit capable of reversing the recording medium recorded on the front surface by the recording unit and recording on the back surface by the recording unit, and the selection condition further includes a predetermined printing duty on the front surface The recording apparatus according to claim 1, further comprising: a condition for selecting the second skew correction processing mode before the recording of the back surface by the recording unit when the value exceeds the value of.

  According to this application example, even if the leading end of the recording medium is bent due to the printing duty on the surface exceeding a predetermined value, the leading end of the recording medium is not nipped between the transport driving roller and the transport driven roller. Guided to position.

  Application Example 6 In the second skew correction processing mode, a waiting time from when the conveyance driving roller stops rotating in the forward rotation direction until the conveyance driving roller is rotated in the reverse rotation direction is set. The recording apparatus according to claim 1, wherein the waiting time is longer than the waiting time in the first skew correction processing mode.

  According to this application example, after the rotation of the conveyance drive roller in the forward rotation direction is stopped, the conveyance drive roller is rotated in the reverse rotation direction, and then rotated in the normal rotation direction again to return the tip to the nip position. In the elapsed time up to the time point, the elapsed time in the second skew correction processing mode is longer than the elapsed time in the first skew correction processing mode.

  Application Example 7 In the second skew correction processing mode, the rotation speed of the transport driving roller in the reverse rotation direction is made slower than the rotation speed of the transport driving roller in the reverse rotation direction in the first skew correction processing mode. The recording apparatus as described above.

  According to this application example, after the rotation of the conveyance drive roller in the forward rotation direction is stopped, the conveyance drive roller is rotated in the reverse rotation direction, and then rotated in the normal rotation direction again to return the tip to the nip position. In the elapsed time up to the time point, the elapsed time in the second skew correction processing mode is longer than the elapsed time in the first skew correction processing mode.

  Application Example 8 In the second skew correction processing mode, the rotational acceleration of the transport driving roller is made slower than the rotational acceleration of the transport driving roller in the first skew correction processing mode. .

  According to this application example, after the rotation of the conveyance drive roller in the forward rotation direction is stopped, the conveyance drive roller is rotated in the reverse rotation direction, and then rotated in the normal rotation direction again to return the tip to the nip position. In the elapsed time up to the time point, the elapsed time in the second skew correction processing mode is longer than the elapsed time in the first skew correction processing mode.

FIG. 2 is a schematic diagram illustrating a schematic configuration of a recording apparatus. The figure which shows the feeding path | route in front sheet feeding. The figure which shows the feeding path | route in rear paper feeding. The figure for demonstrating an inversion path | route. The block block diagram which shows an electric structure. The figure which shows the initial state which made the front end of a paper bite in skew correction processing. The figure which shows the state which discharged the front end of the sheet | seat upstream in the skew correction process. The figure which shows the state which the skew correction process was complete | finished and the front-end | tip of the paper was bitten again. The graph which shows the rotation direction and rotation speed of a conveyance drive roller in 1st skew correction processing mode. The graph which shows the rotation direction and rotation speed of a conveyance drive roller in the 1st skew correction process mode and the 2nd skew correction process mode. 6 is a flowchart showing a flow of processing executed by selecting a first skew correction processing mode or a second skew correction processing mode according to a selection condition. 9 is a flowchart showing a flow of processing executed by selecting a first skew correction processing mode or a second skew correction processing mode according to a selection condition in the second embodiment. The figure which shows a mode that the sheet | seat fed front is approaching a conveyance drive roller and a conveyance driven roller. The figure which shows a mode that the paper with which rear feeding was carried out approaches a conveyance drive roller and a conveyance driven roller. FIG. 9 is a block configuration diagram illustrating an electrical configuration of a printer according to a third embodiment. 10 is a flowchart showing a flow of processing executed by selecting a first skew correction processing mode or a second skew correction processing mode according to a selection condition in the third embodiment. 15 is a flowchart showing a flow of processing executed by selecting a first skew correction processing mode or a second skew correction processing mode according to a selection condition in the fourth embodiment. 10 is a graph showing a rotation direction and a rotation speed of a conveyance drive roller in a first skew correction processing mode and a second skew correction processing mode in Embodiment 5. 14 is a graph showing the rotation direction and the rotation speed of the conveyance drive roller in the first skew correction processing mode and the second skew correction processing mode in the sixth embodiment. The figure which shows the structure by which a conveyance drive roller is arrange | positioned upwards and a conveyance driven roller is arrange | positioned below. The figure which shows the structure by which a conveyance drive roller is arrange | positioned upwards and a conveyance driven roller is arrange | positioned below.

Embodiments of the present invention will be described with reference to the drawings.
(Embodiment 1)
FIG. 1 is a schematic diagram illustrating a schematic configuration of an ink jet printer (hereinafter referred to as a printer) 1 which is an example of a recording apparatus. An arrow direction X indicates a moving direction (vertical direction in the drawing) in which the carriage 15 reciprocates, and an arrow direction Y indicates a conveyance direction of the paper (recording medium). The upstream and downstream descriptions refer to directions in the transport direction Y. The arrow direction Z indicates the vertical direction. The description of the upper side, the upper side, the upper side, the lower side, the lower side, the lower side, and the like refers to a direction or a part in the vertical direction Z.

  Under the printer 1, a paper cassette 21 on which paper P1 as a recording medium is stacked is provided. On the upper side of the paper cassette 21, there is provided a pickup roller 20 that contacts the top of the stacked paper P1 and feeds the paper P1 upward. The pickup roller 20 is provided in a roller holder 19 that can swing around the rotation shaft 18 as a fulcrum.

  A feeding roller 5 is provided above the pickup roller 20. On the outer periphery of the feeding roller 5, driven rollers 4, 25, and 27 that are rotated by driving rotation of the feeding roller 5 are provided.

  Above the feeding roller 5, guide members 2 and 3 for guiding the paper P <b> 2 (recording medium) gripped by the user to the upper side of the feeding roller 5 are provided.

  On the downstream side of the feeding roller 5, a conveyance driving roller 8 and a conveyance driven roller 9 that rotates following the driving rotation of the conveyance driving roller 8 are provided. The transport driven roller 9 is provided in a roller holder 10 that can be swung with the rotating shaft 11 as a fulcrum. The roller holder 10 is provided with a biasing member (not shown) that biases the transport driven roller 9 in a direction of pressing the transport driven roller 9 against the transport driving roller 8.

  A carriage 15 that reciprocates in the movement direction X is provided on the downstream side of the conveyance drive roller 8, and a recording head 14 that ejects ink is provided below the carriage 15. A support member 16 is provided below the recording head 14, and supports the paper P1 or the paper P2 transported at a position facing the recording head 14 from below. The recording unit 13 includes the recording head 14, the carriage 15, and the support member 16.

  On the downstream side of the recording head 14, a discharge driving roller 17 a and a discharge driven roller 17 b that rotates following the driving rotation of the discharge driving roller 17 a are provided. The sheets P1, P2 on which images are recorded by the recording unit 13 while being transported by the transport driving roller 8 and the transport driven roller 9 are discharged downstream by the discharge driving roller 17a and the discharge driven roller 17b.

  FIG. 2 is a diagram illustrating a feeding path in front sheet feeding. When the plurality of sheets P1 move along the separation slope 22 by the rotation of the pickup roller 20 in the rotation direction D1, the separation slope 22 separates the plurality of sheets P1 into one sheet P1.

  The separated sheet P1 moves along the curved feeding path K1 indicated by the broken line arrow. The curved feeding path K1 passes between the guide member 23 and the lower part of the guide member 24, between the feed roller 5 and the upper part of the guide member 24, and between the feed roller 5 and the guide member 26. Is a curved feed path through

  In the curved feeding path K <b> 1, the paper P <b> 1 fed by the pickup roller 20 is fed upward along the guide surface 24 a of the guide member 24. Then, the paper P1 is nipped and fed between the feeding roller 5 that rotates in the rotation direction D2, the driven roller 25, and the driven roller 4. At this time, the paper P1 is guided by the guide surface 26a of the guide member 26, and further turned along the guide surface 6a of the guide member 6 and along the transport path 12a of the guide member 12 extending in the transport direction Y. And then conveyed downstream.

  In this way, the front paper feed path is such that the paper P1 placed on the paper cassette 21 is fed from the front side to the back side (from the downstream side to the upstream side in the transport direction Y), and passes through the curved feed path K1. As described above, the route is fed to the recording unit 13.

  FIG. 3 is a diagram illustrating a feeding path in rear sheet feeding. A straight feed path K2 indicated by a broken line arrow is a straight feed path that is provided above the feed roller 5 and extends along the guide surface 2a of the guide member 2.

  The user grasps the paper P <b> 2 by hand and inserts it between the guide member 2 and the guide member 3. The leading edge of the sheet P2 is guided by the guide surface 2a of the guide member 2 and the guide surface 3a of the guide member 3, and is sandwiched between the feeding roller 5 and the driven roller 4 that rotate in the rotation direction D2, and is guided by the guide member 6. It is fed along the surface 6a. Then, the sheet P2 is transported downstream along the transport path 12a of the guide member 12 extending in the transport direction Y.

  FIG. 4 is a diagram for explaining the inversion paths H1, H2, H3, and H4 indicated by broken line arrows. The paper P1 placed on the paper cassette 21 in FIG. 2 is fed by the curved feeding path K1, recorded on the front surface by the recording unit 13, and recorded on the back surface by passing through the reversing paths H1 to H4 in FIG. Is possible. Similarly, the sheet P2 inserted along the guide member 2 in FIG. 3 is fed by the linear feeding path K2, recorded on the surface by the recording unit 13, and passes through the inversion paths H1 to H4 in FIG. Recording on the back side is possible.

  In the recording unit 13 of FIG. 4, the sheets P1 and P2 recorded on the surface follow the conveyance path 12a as indicated by the reversal path H1 by the rotation direction D4 opposite to the rotation direction D3 of the conveyance drive roller 8. To the upstream side (right side of the drawing).

  The sheets P1 and P2 are sandwiched between the feeding roller 5 and the driven roller 27 that rotate in the rotation direction D2, and pass between the guide member 23 and the feeding roller 5. The sheets P1 and P2 are sandwiched between the feeding roller 5 and the driven roller 25 and pass between the guide members 24 and 26 and the feeding roller 5, as indicated by the reversal paths H2 and H3.

  The sheets P1 and P2 are sandwiched between the feeding roller 5 and the driven roller 4 and conveyed downstream along a reversing path H4 passing below the guide member 6. At this time, the back surfaces of the sheets P1 and P2 are positioned on the side facing the recording head 14. Accordingly, recording is performed on the back surface of the sheets P1 and P2 in the recording unit 13.

  A reversing unit 28 is configured including the feeding roller 5, driven rollers 4, 25, 27 and guide members 6, 12, 23, 24, 26. As described above, the reversing unit 28 can form the reversing paths H1 to H4 and record on both the front and back surfaces of the sheets P1 and P2.

  FIG. 5 is a block configuration diagram showing an electrical configuration of the printer 1. The control unit 30 of the printer 1 includes a CPU 32, a ROM 33, a RAM 34, a character generator (CG) 35, a nonvolatile memory 36, a bus 37, motor drive circuits 38, 39, and 40, a head drive circuit 41, an ASIC 42, an interface (I / F). ) 31.

  The ROM 33 stores a control program for controlling the printer 1 and data necessary for processing. The CPU 32 reads a control program and data from the ROM 33 to the RAM 34 via the bus 37, and executes arithmetic processing and control. In the CG 35, a dot pattern corresponding to the print signal input to the ASIC 42 is developed and stored. The nonvolatile memory 36 stores data that needs to be saved even after the printer 1 is turned off. The I / F 31 transmits / receives data to / from an external computer 60 placed outside the printer 1.

  The carriage motor 43 is a motor for moving the carriage 15 in FIG. The rotation shaft of the carriage motor 43 is directly connected to the rotation shaft of one pulley of a pair of pulleys (not shown) on which an endless belt (not shown) is hung. The carriage 15 is fixed to the endless belt, and the endless belt is rotated by the drive rotation of the carriage motor 43, and the carriage 15 moves in the movement direction X.

  The feed motor 44 is a motor for driving and rotating the feed roller 5 of FIG. 1 via a transmission mechanism such as a gear (not shown). The transport motor 45 is a motor for driving and rotating the transport drive roller 8 via a transmission mechanism such as a gear (not shown).

  The carriage motor 43, the feed motor 44, and the transport motor 45 are stepping motors. Pulse drive voltages are output from the motor drive circuits 38, 39, and 40, and the carriage motor 43, the feed motor 44, and the transport motor 45 are driven to rotate.

  The ASIC 42 supplies the motor drive circuits 38, 39, and 40 with control signals for performing rotational drive control of the carriage motor 43, the feed motor 44, and the carry motor 45 based on the control instruction from the CPU 32. Further, the ASIC 42 supplies a control signal for performing ejection drive control of the recording head 14 to the head drive circuit 41 based on a control instruction from the CPU 32.

  The carriage position detection means 46 is constituted by a linear encoder that reads a stripe drawn extending in the movement direction X, and detects the position of the carriage 15 in the movement direction X. The rotation amount detection means 47 is constituted by a rotary encoder that reads a concentric stripe, and detects the rotation speed, rotation direction, and rotation position of the rotation shaft of the transport motor 45.

  The paper edge detection unit 48 and the paper width detection unit 49 are optical sensors. The paper end detection unit 48 detects the passage time of the end in the transport direction Y of the papers P1 and P2. The paper width detection unit 49 is provided in the carriage 15 and detects the end of the paper P1, P2 in the width direction (movement direction X).

  The first skew correction processing mode 50 and the second skew correction processing mode 51 function by the ASIC 42 controlling the motor drive circuit 40 and the rotation direction and rotation speed of the transport motor 45 according to the control instruction of the CPU 32. To do.

Next, a processing method of the skew correction process will be described.
FIG. 6 shows an initial state in which the leading ends P1a and P2a on the downstream side of the sheets P1 and P2 are bitten (clamped) by the transport driving roller 8 and the transport driven roller 9 in the skew correction process, that is, FIG. 4 is a diagram illustrating a state where the leading ends P1a and P2a protrude downstream from the nip position N between the transport driving roller 8 and the transport driven roller 9.

  When the leading ends P1a and P2a of the sheets P1 and P2 conveyed downstream are projected downstream from the nip position N between the conveyance driving roller 8 and the conveyance driven roller 9, the rotation of the conveyance driving roller 8 is stopped. At this time, the upstream side of the sheets P1 and P2 is sandwiched between the feeding roller 5 and the driven roller 4 that rotate in the rotation direction D2.

  FIG. 7 is a diagram illustrating a state in which the leading ends P1a and P2a of the sheets P1 and P2 are discharged upstream in the skew correction processing. When the transport driving roller 8 is rotated in the reverse direction D4 from the state of FIG. 6, the leading ends P1a and P2a of the sheets P1 and P2 are located upstream from the nip position N between the transport driving roller 8 and the transport driven roller 9. The leading ends P1a and P2a of the sheets P1 and P2 are in contact with the transport driving roller 8 and the transport driven roller 9.

  At this time, the upstream side of the sheets P1 and P2 is sandwiched between the feeding roller 5 and the driven roller 4 that rotate in the rotation direction D2. Therefore, as shown in FIG. 7, the sheets P1 and P2 are greatly bent, and the leading ends P1a and P2a of the sheets P1 and P2 press the transport driving roller 8 and the transport driven roller 9 from the upstream side.

  Even when the upstream side of the sheets P1 and P2 is sandwiched between the feeding roller 5 and the driven roller 4, the direction of the sides of the sheets P1 and P2 extending in the moving direction X of the leading ends P1a and P2a can be changed. Is the thickness. Thus, when the direction of the side extending in the moving direction X of the tips P1a and P2a is inclined with respect to the moving direction X, the direction of the side extending in the moving direction X of the tips P1a and P2a It will be in the state which follows the part of the nip position extended in the moving direction X of the driven roller 9. FIG. That is, the skew correction processing is executed on the sides extending in the moving direction X of the leading ends P1a and P2a of the sheets P1 and P2.

  FIG. 8 is a diagram illustrating a state in which the skew correction processing is completed and the leading ends P1a and P2a of the sheets P1 and P2 are bitten again (clamped state). When the transport driving roller 8 is rotated forward in the rotational direction D3 from the state of FIG. 7, the leading ends P1a and P2a of the papers P1 and P2 are sandwiched between the transport driving roller 8 and the transport driven roller 9, and the papers P1 and P2 are It is conveyed downstream.

  FIG. 9 is a graph showing the rotation direction and rotation speed of the transport drive roller 8 in the first skew correction processing mode 50 with broken lines. From time t0 to time t1, the transport driving roller 8 is rotated forward in the rotation direction D3 at a constant rotational speed V1, and the leading ends P1a and P2a of the papers P1 and P2 are bitten by the transport driving roller 8 and the transport driven roller 9. It is set to the initial state which was made to show (refer FIG. 6).

  From time t1 to time t2, the rotational speed is decelerated, and the rotational speed becomes zero at time t2. The time point t2 is a time point at which the transport driving roller 8 starts to reversely rotate in the rotation direction D4.

  From time t2 to time t3, the transport driving roller 8 is reversely rotated in the rotation direction D4 and the rotation speed is accelerated, and from time t3 to time t4, the rotation speed is constant V2. Accordingly, the leading ends P1a and P2a of the sheets P1 and P2 in FIG. 7 are discharged from the transport driving roller 8 and the transport driven roller 9 to the upstream side (see FIG. 7).

  From time t4 to time t5, the rotational speed of the transport drive roller 8 is decelerated, and the rotational speed becomes zero at time t5. From time t5 to time t7, the transport driving roller 8 is rotated forward in the rotational direction D3 and the rotational speed is accelerated, and reaches a constant rotational speed V1 at time t7.

  At time t6, between the time t5 and the time t7, the transport driving roller 8 is rotated forward in the rotation direction D3 and the rotational speed is accelerated, so that the leading ends P1a and P2a of the sheets P1 and P2 are brought into contact with the transport driving roller 8. This is a point in time when the sheet is returned to the nip position N with the conveyance driven roller 9 and is nipped, that is, when it is caught.

  After time t7, the paper P1, P2 is transported downstream at a constant speed V1 with the transport driving roller 8 rotated forward in the rotational direction D3 (see FIG. 8).

  FIG. 10 is a graph showing the rotation direction and rotation speed of the transport drive roller 8 in the second skew correction processing mode 51 with a solid line. FIG. 10 is a graph in which a graph indicated by a broken line in the first skew correction processing mode 50 of FIG. 9 is overlaid with a graph indicated by a solid line in the second skew correction processing mode 51 for comparison.

  The rotation speed indicated by the solid line in FIG. 10 is the same as the rotation speed indicated by the broken line in FIG. 9, from the time point t0 to the time point t1, the conveyance drive roller 8 is rotated forward in the rotation direction D3 at a constant rotation speed V1. Then, the leading ends P1a and P2a of the sheets P1 and P2 are brought into an initial state where they are bitten by the transport driving roller 8 and the transport driven roller 9 (see FIG. 6). Further, the rotation speed is decelerated from time t1 to time t2, and the rotation speed becomes zero at time t2.

  In the second skew correction processing mode 51 in FIG. 10, a waiting time WT in which the rotation of the transport driving roller 8 is stopped is set from time t2 to time t10. That is, during the waiting time WT, the rotational speed is zero.

  From time t10 to time t11, the transport driving roller 8 is reversely rotated in the rotation direction D4, and the rotation speed is accelerated. From time t11 to time t12, the rotation speed is constant V2. Thus, the leading ends P1a and P2a of the sheets P1 and P2 in FIG. 7 are discharged from the nip position N between the transport driving roller 8 and the transport driven roller 9 to the upstream side (see FIG. 7).

  From time t12 to time t13, the rotational speed of the transport drive roller 8 is decelerated, and the rotational speed becomes zero at time t13. From time t13 to time t15, the transport drive roller 8 is rotated forward in the rotational direction D3, and the rotational speed is accelerated, and reaches a constant rotational speed V1 at time t15.

  At a time point t14, between the time point t13 and a time point t15, the transport driving roller 8 is rotated forward in the rotation direction D3 and the rotational speed is accelerated, so that the leading ends P1a and P2a of the sheets P1 and P2 are brought into contact with the transport driving roller 8. This is a point in time when the sheet is returned to the nip position N with the conveyance driven roller 9 and is nipped, that is, when it is caught.

  The elapsed time TA in FIGS. 9 and 10 is obtained by rotating the conveyance drive roller 8 in the reverse rotation direction D4 from the time t2 when the rotation of the conveyance drive roller 8 in the normal rotation direction D3 is stopped in the first skew correction processing mode 50. After that, the elapsed time until the time point t6 when the tips P1a and P2a return to the nip position N by rotating again in the forward rotation direction D3.

  The elapsed time TB in FIG. 10 is obtained by rotating the transport drive roller 8 in the reverse rotation direction D4 from the time t2 when the rotation of the transport drive roller 8 in the forward rotation direction D3 is stopped in the second skew correction processing mode 51. This is the elapsed time until time t14 when the tips P1a and P2a return to the nip position N by rotating again in the forward rotation direction D3.

  As described above, in the second skew correction processing mode 51 of FIG. 10, the waiting time WT during which the rotation of the transport driving roller 8 is stopped is set from the time point t2 to the time point t10. Further, the time for rotating at a constant rotational speed V2 from time t11 to time t12 in FIG. 10 is the same length of time as rotating at the constant rotational speed V2 from time t3 to time t4 in FIG. The rate of deceleration or acceleration at the rotational speed indicated by the solid line in FIG. 10 is the same as the rate of deceleration or acceleration at the rotational speed indicated by the broken line in FIG. Accordingly, the elapsed time TB in the second skew correction processing mode 51 of FIG. 10 is longer than the elapsed time TA in the first skew correction processing mode 50.

  As a result, when the leading ends P1a and P2a try to return to the nip position N again while the thin sheets P1 and P2 are skewed, even if the leading end is bent, the leading end is less bent and can be guided to the nip position N. The possibility of returning to a correct posture is increased. Therefore, it is possible to prevent the sheets P1 and P2 from being jammed and not being conveyed downstream.

  Next, conditions for selecting the first skew correction processing mode 50 or the second skew correction processing mode 51 of FIG. 5 will be described. FIG. 11 is a flowchart showing a flow of processing to be executed by selecting the first skew correction processing mode 50 or the second skew correction processing mode 51 according to the selection condition in the present embodiment.

  In step S10, the CPU 32 in FIG. 5 acquires the paper types of the papers P1 and P2 from the external computer 60 via the I / F 31, and determines whether the papers P1 and P2 are thin paper or thick paper. For example, when the paper type is “plain paper” or “super fine paper”, it is determined as thin paper, and when the paper type is “glossy paper”, it is determined as thick paper.

  When it is determined that the paper is thin (Yes), the process proceeds to step S110, the control unit 30 executes the second skew correction processing mode 51, and the process ends. When it is determined that the paper is thick (No), the process proceeds to step S100, the control unit 30 executes the first skew correction processing mode 50, and the process ends.

  As described above, when the CPU 32 determines that the paper is thin, the control unit 30 selects and executes the second skew correction processing mode 51. As a result, the skew correction processing in which the elapsed time TB in the second skew correction processing mode 51 in FIG. 10 is set, which is longer than the elapsed time TA in the first skew correction processing mode 50 in FIG. 9 is executed.

  As described above, the printer 1 described in the present embodiment has the transport driving roller 8 when the leading ends of the sheets P1 and P2 transported from the upstream side are sandwiched between the transport driving roller 8 and the transport driven roller 9 that rotate in the forward direction. The rotation in the forward rotation direction D3 is stopped (see FIG. 6), and the conveyance drive roller 8 is rotated in the reverse rotation direction until the leading ends P1a and P2a are disengaged upstream from the nip position N between the conveyance drive roller 8 and the conveyance driven roller 9. The recording apparatus performs skew correction processing on the sheets P1 and P2 by rotating the transport driving roller 8 in the forward rotation direction D3 again (see FIG. 8) after rotating the sheet to D4 (see FIG. 7).

  The printer 1 controls the recording unit 13 of FIG. 1 arranged on the downstream side of the transport driving roller 8 in the transport direction Y of the papers P1 and P2, the rotational direction and the rotational speed of the transport driving roller 8, and the first condition is selected according to the selection conditions. And a control unit 30 that selects and executes the first skew correction processing mode 50 (see FIG. 9) or the second skew correction processing mode 51 (see FIG. 10).

  Then, from the time point t2 in FIG. 9 where the rotation of the transport drive roller 8 in the forward rotation direction D3 is stopped, the transport drive roller 8 is rotated in the reverse rotation direction D4 and then rotated in the forward rotation direction D3 again, thereby leading the tip P1a. , P2a, the elapsed time TB in the second skew correction processing mode 51 is longer than the elapsed time TA in the first skew correction processing mode 50 until the time point when P2a returns to the nip position N.

  The selection condition for selecting the first skew correction processing mode 50 or the second skew correction processing mode 51 is to select the first skew correction processing mode 50 when it is determined that the sheets P1 and P2 are thick. When it is determined that the sheets P1 and P2 are thin, the second skew correction processing mode 51 is selected.

  With this configuration, when the leading ends P1a and P2a that have moved upstream from the nip position N between the transport driving roller 8 and the transport driven roller 9 return to the nip position N again, the leading ends of the thin sheets P1 and P2 are bent. However, the bending (curvature) of the leading ends of the thin sheets P1 and P2 is reduced, and a time for returning to the shape that can be guided to the nip position N is secured. Therefore, it is possible to suppress the sheets P1 and P2 from being jammed in the conveyance path.

  Further, in the first skew correction processing mode 50, the control unit 30 in the present embodiment moves the transport drive roller 8 in the reverse rotation direction from the time point t2 in FIG. 9 when the rotation of the transport drive roller 8 in the normal rotation direction D3 is stopped. In the second skew correction processing mode 51, the rotation in the forward rotation direction D3 of the transport driving roller 8 is stopped in the second skew correction processing mode 51 without setting the waiting time until the rotation to D4 (the waiting time setting time is 0 second). A waiting time WT from time t2 to time t10 when the conveyance driving roller 8 starts to rotate in the reverse rotation direction D4 is set.

  In the first skew correction processing mode 50, when a time exceeding 0 second is set as the waiting time WT, the waiting time WT in the second skew correction processing mode 51 is the waiting time in the first skew correction processing mode 50. It is set longer than WT.

  According to this configuration, after the rotation of the conveyance drive roller 8 in the forward rotation direction D3 is stopped, the conveyance drive roller 8 is rotated in the reverse rotation direction D4 and then again rotated in the normal rotation direction D3. Thus, the elapsed time TB in the second skew correction processing mode 51 in FIG. 10 is more than the elapsed time TA in the first skew correction processing mode 50 in the elapsed time until the leading ends P1a and P2a return to the nip position N. become longer.

(Embodiment 2)
In the first embodiment, the selection condition for selecting the first skew correction processing mode 50 or the second skew correction processing mode 51 includes a condition depending on the thicknesses of the sheets P1 and P2. In the second embodiment, the selection condition Further, a case will be described in which a condition based on the feeding path of the sheets P1 and P2 and a condition based on the sizes of the sheets P1 and P2 are included. FIG. 12 is a flowchart showing a flow of processing to be executed by selecting the first skew correction processing mode 50 or the second skew correction processing mode 51 according to the selection condition in the present embodiment.

  In step S10, the CPU 32 executes the same process as in step S10 of FIG. 11 described in the first embodiment, and when it is determined that the paper is thin (Yes), the process proceeds to step S20 of FIG. When it is determined (No), the process proceeds to step S100, the control unit 30 executes the first skew correction processing mode 50, and the process ends.

  In step S20, the CPU 32 determines whether the paper is rear-fed or front-fed. When the paper P2 is rear fed (Yes), the process proceeds to step S30. When the paper P1 has been fed front (No), the process proceeds to step S100, the control unit 30 executes the first skew correction processing mode 50, and the process ends.

  In step S30, it is determined whether or not the size of the rear fed paper P2 is A4 or more. When the size of the paper P2 is A4 or more (Yes), the process proceeds to step S110, the second skew correction processing mode 51 is executed by the control unit 30, and the processing ends. When the size of the rear fed paper P2 is less than A4 (No), the process proceeds to step S100, the control unit 30 executes the first skew correction processing mode 50, and the process ends.

  13A is a view as seen from the moving direction X, and shows a state in which the paper P1 fed front from the paper cassette 21 of FIG. 2 approaches the nip position N between the transport driving roller 8 and the transport driven roller 9. FIG. is there. FIG. 13B is a view as seen from the moving direction X, and shows a state in which the paper P2 fed rearward along the guide member 2 in FIG. 3 approaches the nip position N between the transport driving roller 8 and the transport driven roller 9. FIG.

  The sheet P1 in FIG. 13A is fed from the front and is fed through the curved feeding path K1 in FIG. Therefore, the leading edge of the sheet P1 is still affected by the curved shape when passing through the curved feeding path K1, and approaches the nip position N in a posture in which the leading edge P1a faces downward. The front end P1a abuts on the outer peripheral surface of the transport driving roller 8 that rotates in the forward rotation direction D3 and is guided to the nip position N.

  The sheet P2 in FIG. 13B is fed rearward and is fed through the linear feeding path K2 in FIG. When the rear paper is fed, the direction in which the front end P2a faces is not determined. Therefore, when approaching the nip position N with the front end P2a facing upward, as shown in FIG. 13B, the lower end of the roller holder 10 that holds the transport driven roller 9 is contacted. As a result, the paper P2 may be jammed.

  The printer according to the present embodiment includes a linear feeding path K2 in which the feeding path is formed in a linear shape, and a curved feeding path K1 in which the feeding path is formed in a curved shape, and the first skew correction processing. The selection condition for selecting the mode 50 or the second skew correction processing mode 51 includes a condition (step S10) based on the thicknesses of the sheets P1 and P2, and the sheet P1 fed from the front is further fed by the curved feeding path K1. When the paper is fed, the first skew correction processing mode 50 is selected, and when the rear-feed paper P2 is fed by the linear feeding path K2, the second skew correction processing mode 51 is selected. Including a condition (step S20).

  With this configuration, when the sheet is fed by the linear feeding path K2 in the rear sheet feeding, the leading end P2a that has moved upstream from the nip position N between the transport driving roller 8 and the transport driven roller 9 is again in the nip position. When returning to N, even if the leading end of the thin paper P2 is bent, the bending is reduced, and a time for returning to the shape that can be guided to the nip position N is secured.

  The selection condition for selecting the first skew correction processing mode 50 or the second skew correction processing mode 51 is that the first skew correction is performed when the size of the rear fed paper P2 is smaller than A4. When the processing mode 50 is selected and the size of the paper P2 is A4 or larger, the condition (step S30) for selecting the second skew correction processing mode 51 is included.

  As the size of the paper P2 increases, the bending of the leading end at the end in the moving direction X that intersects the transport direction Y of the paper P2 increases. According to the present embodiment, when the size of the paper P2 is A4 or more, the control unit 30 executes the second skew correction processing mode 51.

  As a result, when the leading end P2a of the transport driving roller 8 and the transport driven roller 9 that has been removed upstream from the nip position N returns to the nip position N again, even if the leading end of the thin paper P2 is bent, the bending is small. Thus, a time for returning to the shape that can be guided to the nip position N is secured. Other configurations of the printer in the present embodiment are the same as the configurations of the printer 1 described in the first embodiment.

  In the present embodiment, in the selection condition for selecting the first skew correction processing mode 50 or the second skew correction processing mode 51, in addition to the condition depending on the thickness of the paper P1, P2, the paper P1, P2 is further supplied. Although the condition based on the fed feeding path (step S20) and the condition based on the size of the paper P2 (step S30) are included, either one of the condition based on the feeding path and the condition based on the size may be included. .

(Embodiment 3)
In the third embodiment, a case will be described in which the selection conditions for selecting the first skew correction processing mode 50 or the second skew correction processing mode 51 further include conditions based on the temperature and humidity inside the housing. FIG. 14 is a block configuration diagram showing an electrical configuration of the printer 1a in the present embodiment. FIG. 14 is obtained by adding a temperature detection unit 52 and a humidity detection unit 53 to the block configuration diagram of FIG. 5 described in the first embodiment. The temperature detection unit 52 is configured by a thermistor and detects the temperature inside the housing of the printer 1a. The humidity detector 53 detects the humidity inside the housing of the printer 1a.

  FIG. 15 is a flowchart showing a flow of processing for selecting the first skew correction processing mode 50 or the second skew correction processing mode 51 in the present embodiment. The processing content from step S10 to step S30 is the same as the processing content described in the second embodiment with reference to the flowchart of FIG.

  In step S20, when the paper P2 is rear fed (Yes), the process proceeds to step S30, and when the paper P1 is front fed (No), the process proceeds to step S40.

  In step S30, when the size of the rear fed paper P2 is A4 or larger (Yes), the process proceeds to step S110, the second skew correction processing mode 51 is executed by the control unit 30, and the process ends. When the size of the rear fed paper P2 is less than A4 (No), the process proceeds to step S40.

  In step S40, the CPU 32 detects the temperature inside the housing of the printer 1a using the temperature detection unit 52 of FIG. Further, the CPU 32 detects the humidity inside the housing of the printer 1 a using the humidity detection unit 53.

  When the detected temperature is equal to or higher than the predetermined temperature and the detected humidity is equal to or higher than the predetermined humidity, the CPU 32 determines that the temperature is high temperature and high humidity (Yes), and proceeds to step S110. The second skew correction processing mode 51 is executed, and the processing ends.

  When the detected temperature is lower than the predetermined temperature, or when the detected humidity is lower than the predetermined humidity, it is determined that the temperature is not high temperature and high humidity (No), the process proceeds to step S100, and the control unit 30 performs the first operation. The skew correction processing mode 50 is executed, and the processing ends.

  The printer 1a according to the present embodiment includes a temperature detection unit 52 that detects temperature and a humidity detection unit 53 that detects humidity, and selects the first skew correction processing mode 50 or the second skew correction processing mode 51. If the temperature detected by the temperature detection unit 52 exceeds a predetermined temperature and the humidity detected by the humidity detection unit 53 exceeds a predetermined humidity, the second skew correction processing mode is selected. When 51 is selected and the temperature is equal to or lower than the predetermined temperature or the humidity is equal to or lower than the predetermined humidity, a condition for selecting the first skew correction processing mode 50 is included.

  According to this configuration, the leading ends P1a and P2a of the sheets P1 and P2 are transported by the transport driving roller 8 even if the leading ends of the sheets P1 and P2 are bent under environmental conditions exceeding a predetermined temperature and a predetermined humidity. And the conveyance driven roller 9 are guided to the nip position N, and the paper P1, P2 is prevented from being jammed. Other configurations of the printer in the present embodiment are the same as the configurations of the printer 1 described in the first embodiment.

(Embodiment 4)
In the fourth embodiment, a case will be described in which the selection condition for selecting the first skew correction processing mode 50 or the second skew correction processing mode 51 further includes a condition for selection based on the printing duty of the front surface in duplex printing.

  FIG. 16 is a flowchart showing a flow of processing to be executed by selecting the first skew correction processing mode 50 or the second skew correction processing mode 51 according to the selection condition in the present embodiment. Steps S10 to S40 are the same as those described in the third embodiment with reference to the flowchart of FIG.

  If it is determined in step S40 that the temperature is high temperature and humidity (Yes), the process proceeds to step S110, the control unit 30 executes the second skew correction processing mode 51, and the process ends. When the detected temperature is lower than the predetermined temperature, or when the detected humidity is lower than the predetermined humidity, it is determined that the temperature is not high temperature and high humidity (No), and the process proceeds to step S50.

  In step S50, when it is determined that the paper P1, P2 is conveyed on the reverse paths H1 to H4 in FIG. 4 to perform double-sided printing (Yes), the CPU 32 proceeds to step S60 and determines to perform printing only on the front surface. If (No), the process proceeds to step S100. In step S100, the first skew correction processing mode 50 is executed, and the process ends.

  In step S60, the CPU 32 determines, based on the ink ejection data acquired from the print data on the front surface, the ratio (%) of the amount of ink ejected onto the paper to the maximum amount of ink that can be ejected onto the paper, that is, printing. The duty is calculated, and it is determined whether or not the front surface print duty is equal to or greater than a predetermined print duty.

  When the front surface printing duty is equal to or higher than the predetermined printing duty (Yes), the process proceeds to step S110, the second skew correction processing mode 51 is executed, and the process is terminated. When the front surface printing duty is less than the predetermined printing duty (No), the process proceeds to step S100, the first skew correction processing mode 50 is executed, and the process ends.

  The printer of this embodiment includes a reversing unit 28 that can reverse the sheets P1 and P2 recorded on the front surface by the recording unit 13 of FIG. In the selection condition for selecting 50 or the second skew correction processing mode 51, when the printing duty of the front surface exceeds a predetermined value, the second skew correction processing is performed before recording the back surface by the recording unit 13. The condition for selecting the mode 51 is included.

  According to this configuration, even if the leading end of the sheets P1 and P2 is bent due to the printing duty on the front surface exceeding a predetermined value, the leading ends P1a and P2a of the sheets P1 and P2 are transported with the transport driving roller 8. It is guided to the nip position N with the driven roller 9, and the paper P1, P2 is prevented from being jammed. Other configurations of the printer in the present embodiment are the same as the configurations of the printer 1 described in the first embodiment.

(Embodiment 5)
In the first to fourth embodiments, in the second skew correction processing mode 51 described with reference to FIG. 10, the conveyance drive roller 8 is reversed from the time t <b> 2 when the rotation of the conveyance drive roller 8 in the normal rotation direction D <b> 3 is stopped. Although the waiting time WT until the rotation in the rotation direction D4 is set, in the fifth embodiment, the rotation speed in the reverse rotation direction D4 of the transport driving roller in the second skew correction processing mode 51 is set to the first skew correction processing mode. The method of making it slower than the rotation speed in the reverse rotation direction D4 at 50 will be described.

  FIG. 17 is a graph showing the rotation direction and rotation speed of the transport drive roller 8 in the second skew correction processing mode 51 in the present embodiment by a solid line. The rotation speed and the rotation direction of the transport drive roller 8 in the first skew correction processing mode 50 in the present embodiment are the same as the broken line graph of FIG. 9 described in the first embodiment. FIG. 17 is a graph in which a solid line graph showing the second skew correction processing mode 51 is superimposed on the broken line graph of FIG. 9 for comparison.

  The rotation speed indicated by the solid line in FIG. 17 is the same as the rotation speed indicated by the broken line in FIG. 9, and from time t0 to time t1, the conveyance drive roller 8 is rotated forward in the rotation direction D3 at a constant rotation speed V1. Then, the leading ends P1a and P2a of the sheets P1 and P2 are brought into an initial state where they are bitten by the transport driving roller 8 and the transport driven roller 9 (see FIG. 6). Further, the rotation speed is decelerated from time t1 to time t2, and the rotation speed becomes zero at time t2.

  From time t2 to time t20, the transport driving roller 8 is reversely rotated in the rotation direction D4 and the rotation speed is accelerated, and from time t20 to time t21, the rotation speed is constant V3. Accordingly, the leading ends P1a and P2a of the sheets P1 and P2 in FIG. 7 are discharged from the nip position N between the transport driving roller 8 and the transport driven roller 9 to the upstream side.

  From time t21 to time t22, the rotational speed of the transport drive roller 8 is decelerated, and the rotational speed becomes zero at time t22. From time t22 to time t24, the transport drive roller 8 is rotated forward in the rotational direction D3 and the rotational speed is accelerated, and reaches a constant rotational speed V4 at time t24.

  At a time point t23, between the time point t22 and a time point t24, the transport driving roller 8 is rotated forward in the rotation direction D3 and the rotational speed is accelerated, whereby the leading ends P1a and P2a of the sheets P1 and P2 are moved to the transport driving roller 8. This is the point in time when returning to the nip position N with the transport driven roller 9, that is, the time when the leading ends P 1 a and P 2 a of the paper P 1 and P 2 are caught again by the nip position N between the transport drive roller 8 and the transport driven roller 9. .

  The elapsed time TA in FIGS. 9 and 17 is after the conveyance drive roller 8 is rotated in the reverse rotation direction from the time point t2 when the rotation of the conveyance drive roller 8 is stopped in the first skew correction processing mode 50. This is the elapsed time until time point t6 when the tips P1a and P2a return to the nip position by rotating again in the forward rotation direction.

  The elapsed time TC in FIG. 17 is obtained again after the conveyance drive roller 8 is rotated in the reverse rotation direction from the time t2 when the rotation of the conveyance drive roller 8 is stopped in the second skew correction processing mode 51. This is the elapsed time until time t23 when the tips P1a and P2a return to the nip position by rotating in the rotation direction.

  In the present embodiment, the constant rotational speed V3 from the time point t20 to the time point t21 in the second skew correction processing mode 51 is greater than the constant rotational speed V2 from the time point t3 to the time t4 in the first skew correction processing mode 50. Set late. The rate of deceleration or acceleration at the rotational speed indicated by the solid line in FIG. 17 is the same as the rate of deceleration or acceleration at the rotational speed indicated by the broken line in FIG. Accordingly, the elapsed time TC in the second skew correction processing mode 51 is longer than the elapsed time TA in the first skew correction processing mode 50.

  Accordingly, when the leading edge tries to return to the nip position N again in a state where the thin sheets P1 and P2 are skewed, even if the leading edge is bent, the bending of the leading edge becomes small so that the leading edge can be guided to the nip position N. Time to return is secured. Therefore, it is possible to prevent the sheets P1 and P2 from being jammed and not being conveyed downstream.

  As described above, in the second skew correction processing mode 51, the control unit 30 in the printer according to the present embodiment described above determines the rotation speed V <b> 3 in the reverse rotation direction D <b> 4 of the transport driving roller 8 in the first skew correction processing mode 50. The rotational speed V2 of the roller 8 in the reverse rotation direction D4 is set slower.

  According to this configuration, after the rotation of the transport drive roller 8 in the forward rotation direction D3 is stopped, the transport drive roller 8 is rotated in the reverse rotation direction D4 and then rotated in the forward rotation direction D3 again. In the elapsed time until P1a and P2a return to the nip position N, the elapsed time TC in the second skew correction processing mode 51 indicated by the solid line is the elapsed time TA in the first skew correction processing mode 50 indicated by the broken line. It will be longer. Other configurations of the printer in the present embodiment are the same as the configurations of the printer 1 described in the first embodiment.

(Embodiment 6)
In the sixth embodiment, a method for making the rotational acceleration of the transport driving roller 8 in the second skew correction processing mode 51 slower than the rotational acceleration of the transport driving roller 8 in the first skew correction processing mode 50 will be described.

  FIG. 18 is a graph showing the rotation direction and rotation speed of the transport drive roller 8 in the second skew correction processing mode 51 in the present embodiment by a solid line. The rotation direction and the rotation speed of the transport drive roller 8 in the first skew correction processing mode 50 in the present embodiment are the same as the broken line graph of FIG. 9 described in the first embodiment. FIG. 18 is a graph in which a solid line in the second skew correction processing mode 51 is superimposed on the broken line graph of FIG. 9 for comparison.

  The rotation speed indicated by the solid line in FIG. 18 is the same as the rotation speed indicated by the broken line in FIG. 9, and from time t0 to time t1, the transport drive roller 8 is rotated in the rotation direction D3 at a constant rotation speed V1. Then, the leading ends P1a and P2a of the sheets P1 and P2 are brought into an initial state where they are bitten by the transport driving roller 8 and the transport driven roller 9 (see FIG. 6). Further, the rotation speed is decelerated from time t1 to time t2, and the rotation speed becomes zero at time t2.

  From time t2 to time t30, the transport driving roller 8 is reversely rotated in the rotation direction D4, and the rotation speed is accelerated. From time t30 to time t31, the rotation speed is constant V2. Accordingly, the leading ends P1a and P2a of the sheets P1 and P2 in FIG. 7 are discharged from the nip position N between the transport driving roller 8 and the transport driven roller 9 to the upstream side.

  From time t31 to time t32, the rotational speed of the transport drive roller 8 is decelerated, and the rotational speed becomes zero at time t32. From time t32 to time t34, the transport driving roller 8 is rotated forward in the rotational direction D3 and the rotational speed is accelerated, and reaches a constant rotational speed V1 at time t34.

  At a time point t33, between the time point t32 and a time point t34, the transport driving roller 8 is rotated forward in the rotational direction D3, and the rotational speed is accelerated so that the leading ends P1a and P2a of the sheets P1 and P2 are brought into contact with the transport driving roller 8. This is the point in time when returning to the nip position N with the transport driven roller 9, that is, the time when the leading ends P1a and P2a of the sheets P1 and P2 are again pinched by the nip position N between the transport drive roller 8 and the transport driven roller 9. .

  The elapsed time TA in FIGS. 9 and 18 is after the conveyance drive roller 8 is rotated in the reverse rotation direction from the time t2 when the rotation of the conveyance drive roller 8 is stopped in the first skew correction processing mode 50. This is the elapsed time until time point t6 when the tips P1a and P2a return to the nip position by rotating again in the forward rotation direction.

  The elapsed time TD shown in FIG. 18 is obtained again after the conveyance drive roller 8 is rotated in the reverse rotation direction from the time t2 when the rotation of the conveyance drive roller 8 is stopped in the second skew correction processing mode 51. This is the elapsed time up to time t33 when the tips P1a and P2a return to the nip position by rotating in the rotation direction.

  In the present embodiment, the acceleration rate (rotational acceleration) of the rotational speed in the reverse rotation direction D4 from the time point t2 to the time point t30 in the second skew correction processing mode 51 indicated by the solid line is the first skew correction indicated by the broken line. It is set slower than the acceleration rate (rotational acceleration) of the rotational speed in the reverse rotational direction D4 from time t2 to time t3 in the processing mode 50.

  Furthermore, the acceleration rate (rotational acceleration) of the rotational speed in the positive rotation direction D3 from the time point t32 to the time point t34 in the second skew correction processing mode 51 indicated by the solid line is the first skew correction processing mode 50 indicated by the broken line. Is set slower than the acceleration rate (rotational acceleration) of the rotational speed in the positive rotational direction D3 from time t5 to time t7.

  Accordingly, the elapsed time TD in the second skew correction processing mode 51 is longer than the elapsed time TA in the first skew correction processing mode 50. Accordingly, when the leading edge tries to return to the nip position N again in a state where the thin sheets P1 and P2 are skewed, even if the leading edge is bent, the bending of the leading edge becomes small so that the leading edge can be guided to the nip position N. The possibility of returning is high. Therefore, it is possible to prevent the sheets P1 and P2 from being jammed and not being conveyed downstream.

  As described above, in the second skew correction processing mode 51, the control unit 30 in the printer of the present embodiment described above determines the rotational acceleration of the transport driving roller 8 from the rotational acceleration of the transport driving roller 8 in the first skew correction processing mode 50. Slow down.

  According to this configuration, from the time point t2 when the rotation of the transport drive roller 8 in the forward rotation direction D3 is stopped, the transport drive roller 8 is rotated in the reverse rotation direction D4 and then rotated in the forward rotation direction D3, thereby leading the tip P1a. , P2a, the elapsed time TD in the second skew correction processing mode 51 is longer than the elapsed time TA in the first skew correction processing mode 50 during the elapsed time until the time point P2a returns to the nip position N. Other configurations of the printer in the present embodiment are the same as the configurations of the printer 1 described in the first embodiment.

  In the first to sixth embodiments, the transport driving roller 8 is disposed below and the transport driven roller 9 is disposed above. However, the transport driving roller 70 is disposed above and the transport driven roller 71 is disposed below. The present invention also applies to other configurations.

  For example, when the outer diameter of the transport driven roller 71 is shorter than the outer diameter of the transport drive roller 70, when the paper P3 approaches the nip position N between the transport drive roller 70 and the transport driven roller 71 along the support portion 72, In the state where the tip P3a of FIG. 19A is directed to the transport driving roller 70 side, the tip P3a of FIG. In the state of facing the transport driven roller 71 side, the leading end P3a is not guided to the nip position N, and the paper P3 may be jammed in the transport path.

  Therefore, when the second skew correction processing mode 51 is selected according to the selection condition for selecting the first skew correction processing mode 50 or the second skew correction processing mode 51, the forward rotation direction D5 of the transport driving roller 70 is selected. The elapsed time from the point when the rotation of the roller P is stopped until the tip P3a returns to the nip position N by rotating the conveyance driving roller 70 in the reverse rotation direction and then rotating in the forward rotation direction D5 again is the first time Since the elapsed time in the skew correction processing mode 50 is longer than the elapsed time, when the leading end P3a of the paper P3 that has been removed upstream from the nip position N between the transport driving roller 70 and the transport driven roller 71 returns to the nip position N again, the thin paper Even if the tip of P3 is bent, the bending is reduced, and a time to return to the shape that can be guided to the nip position N is secured.

  DESCRIPTION OF SYMBOLS 1, 1a ... Inkjet printer, 8, 70 ... Conveyance drive roller, 9, 71 ... Conveyance driven roller, 13 ... Recording part, 28 ... Reversing unit, 30 ... Control part, 50 ... 1st skew correction process mode, 51 ... Second skew correction processing mode 52... Temperature detector 53. Humidity detector D 3 forward rotation direction D 4 reverse rotation direction K 1 curved feed path K 2 linear feed path N Nip position P1, P2, P3... Paper, P1a, P2a, P3a ... leading edge, TA, TB, TC, TD ... elapsed time, t2, t6, t14, t23, t33 ... time point, WT ... waiting time, Y ... transport direction.

Claims (8)

When the leading end of the recording medium transported from the upstream side is sandwiched between the transport driving roller and the transport driven roller that rotate in the forward direction, the transport driving roller stops rotating in the positive rotation direction, and the leading end is transported. Recording is performed by rotating the transport drive roller in the reverse rotation direction until it moves upstream from the nip position between the drive roller and the transport driven roller, and then rotating the transport drive roller in the forward rotation direction again. A recording apparatus that performs skew correction processing of a medium,
A recording unit disposed on the downstream side of the transport driving roller in the transport direction of the recording medium;
A control unit that controls a rotation direction and a rotation speed of the transport driving roller, and selects and executes the first skew correction processing mode or the second skew correction processing mode according to a selection condition;
From when the forward rotation direction of the transport drive roller is stopped to when the transport drive roller is rotated in the reverse rotation direction and then rotated again in the forward rotation direction until the tip returns to the nip position. In the elapsed time, the elapsed time in the second skew correction processing mode is longer than the elapsed time in the first skew correction processing mode,
The selection condition is that when the recording medium is determined to be thick, the first skew correction processing mode is selected, and when the recording medium is determined to be thin, the second skew correction processing mode is selected. A recording apparatus comprising: The recording apparatus according to claim 1,
A linear feeding path in which the feeding path is formed in a linear shape;
A curved feeding path in which the feeding path is formed in a curved shape, and
In the selection condition, when the recording medium is further fed by the curved feeding path, the first skew correction processing mode is selected, and the recording medium is fed by the linear feeding path. The recording apparatus includes a condition for selecting the second skew correction processing mode. The recording apparatus according to claim 1 or 2,
The selection condition is that the first skew correction processing mode is selected when the size of the recording medium is less than A4, and the second skew is selected when the size of the recording medium is A4 or more. A recording apparatus including a condition for selecting a correction processing mode. The recording apparatus according to any one of claims 1 to 3,
A temperature detector for detecting the temperature;
A humidity detection unit for detecting humidity;
The selection condition is that the second skew correction processing is performed when the temperature detected by the temperature detector exceeds a predetermined temperature and when the humidity detected by the humidity detector exceeds a predetermined humidity. A recording apparatus comprising: a condition for selecting a first skew correction processing mode when a mode is selected and the temperature is equal to or lower than a predetermined temperature or the humidity is equal to or lower than a predetermined humidity. In the recording device according to any one of claims 1 to 4,
Reversing the recording medium recorded on the front surface by the recording unit, comprising a reversing unit capable of recording on the back surface by the recording unit,
The selection condition further includes a condition for selecting the second skew correction processing mode before the recording of the back surface by the recording unit when the printing duty of the front surface exceeds a predetermined value. A recording apparatus. In the recording device according to any one of claims 1 to 5,
From the time point when the rotation of the conveyance drive roller in the forward rotation direction is stopped, a waiting time is set until the conveyance drive roller is rotated in the reverse rotation direction.
The recording apparatus according to claim 1, wherein the waiting time in the second skew correction processing mode is longer than the waiting time in the first skew correction processing mode. In the recording device according to any one of claims 1 to 5,
In the second skew correction processing mode, the rotation speed of the transport driving roller in the reverse rotation direction is slower than the rotation speed of the transport driving roller in the reverse rotation direction in the first skew correction processing mode. Recording device. In the recording device according to any one of claims 1 to 5,
In the second skew correction processing mode, the rotational acceleration of the transport driving roller is made slower than the rotational acceleration of the transport driving roller in the first skew correction processing mode.

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