JP5569133B2 - Liquid ejector - Google Patents

Description

  The present invention relates to a liquid ejecting apparatus such as an ink jet printer.

  In general, as a kind of liquid ejecting apparatus, an ink jet printer that performs printing by ejecting ink (liquid) from a liquid ejecting head onto a sheet (medium) is widely known. Some of these printers continuously print on a plurality of sheets, discharge (discharge) printed sheets, and stack them on a discharge tray (mounting unit) (for example, Patent Documents). 1).

  In the printer disclosed in Patent Document 1, the vicinity of the rear end of the paper conveyed on the guide member toward the paper discharge tray is pressed with a weight member to correct the curl (curvature) of the paper, thereby continuously discharging the paper. The stacking order of the sheets to be printed is changed, and the succeeding sheet is prevented from pushing the preceding sheet from the discharge tray.

JP-A-7-277581

  However, particularly when performing high-speed printing, the printed paper is discharged onto the paper discharge tray at a high speed, and may be warped after the paper is discharged onto the paper discharge tray. In many cases, such curling of the paper naturally corrects after a few seconds.However, in high-speed printing, the subsequent paper is discharged onto the paper discharge tray before the paper curl on the paper discharge tray. There has been a problem that the preceding paper that has warped on the paper tray prevents the subsequent paper from being discharged onto the paper discharge tray.

  Also, in this case, if the weight member attempts to hold the trailing edge of the discharged paper, the weight member will be disposed near the paper discharge port, so that the weight member itself discharges the subsequent paper. There was a problem that paper could be disturbed.

  The present invention has been made paying attention to such problems existing in the prior art. An object of the present invention is to provide a liquid ejecting apparatus capable of continuously and smoothly ejecting a plurality of media ejected with liquid onto a placement unit.

In order to achieve the above object, a liquid ejecting apparatus according to the present invention includes a transport / discharge unit that continuously transports a plurality of media along a transport path and discharges the medium from a discharge port to a placement unit; A liquid ejecting head that ejects liquid onto each medium at a position, and a control unit that controls a transporting and discharging operation of the transporting and discharging unit, the control unit serving as a preceding medium discharged to the placement unit Based on the warped state of the first medium, the discharge timing of the second medium as the succeeding medium by the transporting and discharging means to the placement unit described above is a timing for avoiding a collision with the first medium in the warped state. In the liquid ejecting apparatus to be controlled , the placement unit is provided with a warp state detection unit that detects a warp state of the first medium discharged to the placement unit, and the transport and discharge unit includes the transport unit. Route A pair of discharge rollers capable of sandwiching each medium upstream of the discharge port, and the warped state detecting means is the highest reach of the first medium in the state of being discharged and warped. It is detected whether or not the part has reached the height of the discharge port in the placement unit, and the control means detects from the detection result by the warped state detection means that the highest reaching part of the first medium is the placement part. When it is determined that the height of the discharge port has not been reached, the transfer / discharge operation of the transfer / discharge means is controlled so that the second medium is discharged to the placement section, and the detection by the warped state detection means is performed. As a result, when it is determined that the highest reach of the first medium has reached the height of the discharge port in the placement section, the front end in the transport direction of the second medium is placed in the transport path. The second medium so as not to exit the outlet stops the conveying operation of discharging the conveying and discharging means while being held on the discharge roller pair.

  According to this invention, since the second medium is discharged to the mounting portion at a timing that avoids the collision with the first medium that is in the warping state in the mounting portion, the discharge of the second medium to the mounting portion is warped. It will not be disturbed by the first medium in the state. Therefore, it is possible to smoothly and smoothly discharge a plurality of media onto which the liquid has been ejected on the placement unit.

In addition , since the warp state of the first medium discharged to the placement unit can be detected by the warp state detection unit, the first part can be detected at a timing that reliably avoids a collision with the first medium in the warp state in the placement unit. It becomes possible to discharge the two media to the placement unit.

Furthermore , since the second medium is discharged to the mounting portion when the highest reachable portion of the first medium that has been discharged to the mounting portion and warped has not reached the height of the discharge port in the mounting portion, The discharge of the two mediums to the placement unit is not hindered by the first medium in a warped state. For this reason, it is possible to smoothly discharge the second medium to the mounting unit without waiting until the warping of the first medium discharged to the mounting unit is completely eliminated.

In addition , the front end in the transport direction of the second medium is discharged in the transport path when the highest reach of the first medium that has been ejected to the placement unit and warped has reached the height of the discharge port in the placement unit. Since it is located upstream from the outlet, it is possible to reliably avoid a collision between the second medium and the first medium that is warped in the mounting portion.

In addition , when the highest reach of the first medium, which has been discharged to the placement unit and is warped, has reached the height of the discharge port in the placement unit, at least the front end of the second medium in the transport direction protrudes from the discharge port. Since the second medium is sandwiched between the pair of discharge rollers so that there is no collision, it is possible to reliably avoid the collision between the second medium and the first medium that is warped in the mounting portion.

In the liquid ejecting apparatus according to the aspect of the invention, the liquid ejecting apparatus may further include an end detection unit that detects a front end in the transport direction of each medium on the upstream side of the discharge roller pair in the transport path.
According to the present invention, at least the front end in the transport direction of the second medium is removed from the discharge port by temporarily stopping the transport / discharge operation of the transport / discharge means based on the timing at which the end detection unit detects the front end of the second medium. It becomes possible not to come out.

The liquid ejecting apparatus of the present invention includes a transport / discharge unit that continuously transports a plurality of media along a transport path and discharges the medium from a discharge port to a placement unit, and supplies liquid to each medium at a position midway along the transport path. A liquid ejecting head for ejecting; and a control unit for controlling the transporting and discharging operation of the transporting and discharging unit. The control unit is based on a warped state of the first medium as the preceding medium discharged to the placement unit. In the liquid ejecting apparatus that controls the discharge timing of the second medium as the subsequent medium by the transporting and discharging means to the timing to avoid the collision with the first medium in the warped state, The control means is configured such that a time required from when the first medium is ejected by the liquid ejecting head to when the second medium is ejected to the placement unit is discharged to the placement unit. First The transporting and discharging means causes the transporting and discharging means to extend the time required for improving the warped state of the first medium to the extent that the second medium discharged to the mounting portion does not collide with the medium. The discharge timing of the second medium to the placement unit is controlled.

  According to the present invention, when the second medium is discharged to the mounting portion, the warping state of the first medium discharged to the mounting portion is improved to such an extent that it does not collide with the second medium. The discharge of the two media to the placement unit is not hindered by the first medium in the warped state. Therefore, it is possible to smoothly and smoothly discharge a plurality of media onto which the liquid has been ejected on the placement unit.

  In the liquid ejecting apparatus according to the aspect of the invention, the transport and discharge unit may include a discharge roller pair capable of sandwiching each medium upstream of the discharge port in the transport path, and the control unit may include a front end of the second medium. By adjusting the time from the stop of the transport / discharge operation of the transport / discharge means to the restart of the transport / discharge operation of the transport / discharge means in a state of being sandwiched between the pair of discharge rollers. Controls the discharge timing to the entry section.

  According to this invention, since the conveyance of the second medium is stopped in a state where the front end of the second medium is sandwiched between the discharge roller pair, it is possible to suppress the warping of the front end side of the second medium during the stop. It becomes possible.

FIG. 3 is a simplified cross-sectional view of the ink jet printer according to the embodiment. FIG. 2 is a block diagram showing an electrical configuration of the printer. The flowchart of the conveyance discharge process routine in embodiment.

  Hereinafter, an embodiment in which the liquid ejecting apparatus of the invention is embodied in an ink jet printer will be described with reference to the drawings. In the following description, the terms “front-rear direction”, “vertical direction”, and “left-right direction” refer to “front-rear direction”, “vertical direction”, and “left-right direction” indicated by arrows in FIG. Direction ".

  As shown in FIG. 1, an ink jet printer 11 as a liquid ejecting apparatus transports a main body case 12 and paper P (P1 to P3) as a medium along a transport path, and places a placement unit 17 from a discharge port 15. A transport discharge device 13 serving as a transport discharge unit that discharges (discharges) the paper, and a recording head 14 serving as a liquid ejecting head that ejects ink as liquid onto the paper P transported by the transport discharge device 13. .

  The recording head 14 has a plurality of nozzles (not shown) that can eject ink. In the present embodiment, the recording head 14 is a line head capable of printing in the maximum paper width range in a fixed state. A platen 19 functioning as a support for supporting the paper P is provided below the recording head 14 in the main body case 12 so as to face the recording head 14.

  The paper P conveyed along the conveyance path receives the ink ejected from the recording head 14 on the platen 19 on the upper surface side (one surface side), so that printing is performed. In the present embodiment, an area on the platen 19 that performs printing on the paper P may be referred to as a print area.

  The transport discharge device 13 includes a paper feed unit 20, a paper discharge unit 21, and a transport motor 22 (see FIG. 2). In the main body case 12, a sheet feeding cassette 23 that can store a plurality of sheets P in a stacked state is detachably mounted below the platen 19.

  The paper feeding unit 20 feeds (conveys) the paper P fed out from the paper cassette 23 by the feeding roller 24 that feeds the paper P stored in the paper feeding cassette 23 to the printing area. A feed path forming member 25 that forms a feed path 25a for the transfer, and a pair of transport rollers 26 to 28 that are arranged on the feed path 25a at intervals.

  The paper discharge unit 21 includes a reverse path forming member 29 that forms a reverse path (discharge path) 29a for reversing the paper P printed in the printing area, and a transport that is disposed on the reverse path 29a at a distance from each other. A roller pair 30 to 32 and a paper discharge roller pair 16 as a discharge roller pair are provided. Each of the transport roller pairs 26 to 28, 30 to 32 and the paper discharge roller pair 16 is driven by a drive roller that is rotationally driven by the transport motor 22 (see FIG. 2) and a driven roller that is urged by the drive roller. It consists of a roller. Further, the feeding roller 24 is rotationally driven by a transport motor 22 (see FIG. 2). In the present embodiment, the feeding path 25a and the reverse path 29a constitute a part of the transport path.

  The paper discharge roller pair 16 is located on the downstream end of the reverse path 29a, that is, immediately upstream of the discharge port 15 opened on the downstream end side of the reverse path 29a. Further, a discharge paper end sensor 33 as an end detection unit capable of detecting both ends in the transport direction of the paper P is provided immediately upstream of the paper discharge roller pair 16 in the reverse path 29a. In addition, a printing paper edge sensor 18 capable of detecting both ends in the conveyance direction of the paper P conveyed toward the printing area is provided between the conveyance roller pair 28 and the recording head 14 on the feeding path. Yes.

  The printing paper edge sensor 18 and the discharge paper edge sensor 33 are reflection-type optical sensors, each having a light emitting part and a light receiving part (not shown). The printing paper end sensor 18 and the discharge paper end sensor 33 are configured such that the light receiving unit receives the reflected light of the light emitted from the light emitting unit and outputs an electrical signal corresponding to the intensity of the reflected light. . In the present embodiment, the printing paper edge sensor 18 and the discharged paper edge sensor 33 output an ON value larger than a predetermined threshold when the paper P is a reflection target, while the paper P is not a reflection target. Sometimes an OFF value that is below the threshold is output.

  Therefore, when the output values of the print paper edge sensor 18 and the discharge paper edge sensor 33 change from the OFF value to the ON value, the front edge of the paper P in the transport direction is detected, while the print paper edge sensor 18 and the discharge paper edge are detected. As the output value of the sensor 33 changes from the ON value to the OFF value, the trailing edge of the paper P in the transport direction is detected.

  As shown in FIG. 1, the placing portion 17 is recessed on the upper surface of the main body case 12 and supports a plurality of sheets P that are sequentially and sequentially discharged from the discharge port 15 in a stacked state. Yes. The depth of the mounting portion 17 is deepest at the left end and gradually becomes shallower toward the right side. That is, the bottom surface 17a of the mounting portion 17 is curved so as to bulge upward, and is inclined so as to rise toward the right side.

  A discharge port 15 extending in the front-rear direction (width direction) perpendicular to the discharge direction of the paper P is opened at a position near the upper end portion on the left surface 17 b of the placement unit 17. In addition, the placement unit 17 is provided with a warping sensor 34 as a warping state detecting unit that detects a warping state of the paper P discharged onto the bottom surface 17a. The warpage return sensor 34 is a reflective optical sensor similar to the printing paper end sensor 18 and the discharge paper end sensor 33, and has a light emitting unit and a light receiving unit (not shown). The warping sensor 34 is disposed at one end in the front-rear direction of the placement portion 17, and the height thereof is set to the same height as the lower end of the discharge port 15.

  Therefore, the warpage return sensor 34 outputs an ON value when the highest reachable portion of the paper P that has warped upward on the bottom surface 17 a of the placement portion 17 reaches the height of the discharge port 15, while the output of the placement portion 17. An OFF value is output when the highest reachable portion of the paper P that has warped upward on the bottom surface 17a does not reach the height of the discharge port 15.

Next, the electrical configuration of the ink jet printer 11 will be described.
As shown in FIG. 2, the ink jet printer 11 includes a control device 40 that controls the operating state of the ink jet printer 11. The control device 40 includes a computer 41 as a control means, a head driver 42, and a motor driver 43. The computer 41 includes a CPU 44, a ROM 45, a RAM 46, and a non-volatile memory 47, and is electrically connected to the head driver 42, the motor driver 43, the discharged paper end sensor 33, the printed paper end sensor 18, and the warp back sensor 34. Yes.

  The computer 41 performs various controls by the CPU 44 executing a control program stored in the ROM 45. That is, the computer 41 drives and controls the recording head 14 via the head driver 42 and ejects ink from each nozzle (not shown) of the recording head 14. Further, the computer 41 drives and controls the transport motor 22 via the motor driver 43.

  The output shaft of the transport motor 22 is provided with a rotary encoder 48 for detecting the rotation speed, rotation position, and rotation direction of the output shaft. The rotary encoder 48 is electrically connected to the computer 41. Yes. Then, the computer 41 controls the driving of the carry motor 22 based on detection signals from the rotary encoder 48, the discharged paper end sensor 33, the printing paper end sensor 18, and the warp back sensor 34. The nonvolatile memory 47 stores a threshold value N and a threshold value R, which will be described later.

Next, the operation of the ink jet printer 11 when printing is continuously performed on a plurality of sheets P (P1 to P3) will be described.
When printing on the paper P, first, the paper P is fed toward the feeding path 25a by rotating the feed roller 24, and the paper is fed by rotating the transport roller pairs 26 to 28. P is conveyed to the printing area. Printing is performed on the upper surface of the paper P by ejecting ink from the recording head 14 when the paper P passes through the printing area. In this case, ink ejection from the recording head 14 is started based on the rotation amount of the transport motor 22 after the front end of the paper P is detected by the printing paper edge sensor 18.

  The printed paper P is transported downstream along the reverse path 29a by rotating the transport roller pairs 30 to 32. At this time, the paper P is reversed so that the printing surface faces downward in the process of being conveyed through the reversing path 29a. Then, by rotating the paper discharge roller pair 16 together with the transport roller pairs 30 to 32, the plurality of sheets P continuously transported along the transport path are discharged in a state where the printing surface faces downward. 15 are sequentially discharged (discharged) to the mounting portion 17 and stacked on the bottom surface 17a of the mounting portion 17 in the discharging order.

  Here, the sheet P is swollen by the ink on the printing surface side, so that when the sheet P is discharged from the discharge port 15, both sides in the width direction (front-rear direction) may warp upward. The warp of the paper P due to such swelling occurs, for example, in about 1 second after printing, and the solvent component of the ink permeates the non-printing surface side (opposite side to the printing surface side) within a few seconds thereafter. It is solved with.

  However, when the paper P is conveyed to the placement unit 17 at high speed after printing, the paper P1 as the first medium, which is the preceding paper P, is warped after being discharged (discharged) onto the placement unit 17. As a result of this warping, a situation may occur in which the paper P2 as the second medium, which is the subsequent paper P, is discharged from the discharge port 15 while the highest reachable portion of the paper P1 reaches the height of the discharge port 15. Then, the front end of the sheet P2 collides with the rear end of the sheet P1 that has warped on the bottom surface 17a of the placement unit 17, and there is a possibility that a jam (paper jam) may occur.

  Therefore, the computer 41 controls the discharge timing of the paper P2 at a timing that avoids a collision between the paper P1 and the paper P2 that have been discharged to the placement unit 17 and turned back. In other words, the computer 41 discharges paper to the placement unit 17 at a timing when the highest reachable portion of the paper P1 that has been discharged to the placement unit 17 and turned back based on the output value of the warp sensor 34 has not reached the height of the discharge port 15. Control to discharge P2 is performed.

  Specifically, when the highest reachable portion of the paper P1 that has been discharged and curled to the placement unit 17 has reached the height of the discharge port 15, the front end of the paper P2 is sandwiched between the paper discharge roller pair 16. In this state, the conveying and discharging operation of the paper P2 is temporarily stopped. Thereafter, when the curled state of the paper P1 is improved to such an extent that it does not collide with the paper P2 discharged from the discharge port 15, the transport and discharge operation of the temporarily stopped paper P2 is resumed. As a result, the plurality of printed sheets P are continuously and smoothly discharged onto the placement unit 17.

Next, a transport / discharge processing routine in which the computer 41 controls the transport / discharge operation of the paper P will be described with reference to the flowchart shown in FIG.
Now, when the number of printed sheets P in the print job received from the host device or the like is two or more, the computer 41 starts the conveyance / discharge processing routine shown in the flowchart of FIG.

  First, in step S11, the computer 41 determines whether or not the paper P to be printed is thin paper. If the determination result of step S11 is negative, the computer 41 ends the transport discharge processing routine. On the other hand, when the determination result of step S11 is affirmative, the computer 41 proceeds to the next step S12. That is, when the preceding paper P1 is a thick paper, it is difficult to bend even if it is printed. On the other hand, when the paper P is a thin paper, it tends to be warped due to printing, and is therefore subject to the transport discharge processing routine.

  In the next step S <b> 12, the computer 41 determines whether or not the preceding paper P <b> 1 is in the placement unit 17. When the determination result in step S12 is negative, the computer 41 periodically repeats the determination in step S12. And if the determination result of this step S12 becomes affirmation determination, the computer 41 will transfer the process to the following step S13.

  That is, when the preceding paper P1 is not on the placement unit 17 (when the first sheet is printed), the subsequent paper P2 does not collide with the preceding paper P1 when the subsequent paper P2 is discharged. Since there is no possibility, it is not the target of the transport discharge processing routine. On the other hand, when the preceding paper P1 is on the placement unit 17 (when the second and subsequent sheets are printed), the subsequent paper P2 collides with the preceding paper P1 when the subsequent paper P2 is discharged. Because it is possible, it is the target of the transport discharge processing routine.

  In the next step S 13, the computer 41 determines whether or not the printing rate for the preceding paper P 1 (paper P printed one sheet ahead) is equal to or greater than the threshold value N stored in the nonvolatile memory 47. . If the determination result of step S13 is negative, the computer 41 proceeds to step S20. On the other hand, when the determination result of step S13 is affirmative, the computer 41 proceeds to the next step S14.

  That is, when the printing rate of the paper P1 is low, the area for receiving ink is small and the paper P1 is unlikely to be warped. On the other hand, when the printing rate of the paper P1 is high, the area for receiving ink is large, and the paper P1 is likely to be warped. The threshold value N can be set to an arbitrary value such as 25%.

  In the next step S14, the computer 41 determines whether or not the warp back sensor 34 has detected the preceding paper P1. If the determination result of step S14 is negative, the computer 41 proceeds to step S20. On the other hand, if the determination result of step S14 is affirmative, the computer 41 proceeds to the next step S15.

  In the next step S15, the computer 41 determines whether or not the discharge paper end sensor 33 has detected the front end of the subsequent paper P2 (paper P conveyed following the paper P1). If the determination result of step S15 is negative, the computer 41 periodically repeats the determination of step S15. And if the determination result of this step S15 becomes affirmation determination, the computer 41 will transfer the process to following step S16.

  In the next step S <b> 16, the computer 41 reaches the threshold value R stored in the non-volatile memory 47 after the discharge paper end sensor 33 detects the front end of the succeeding paper P <b> 2. It is determined whether or not. If the determination result of step S16 is negative, the computer 41 periodically repeats the determination of step S16. And if the determination result of this step S16 becomes affirmation determination, the computer 41 will transfer the process to following step S17. The threshold value R is set to a value at which the front end of the paper P2 whose front end is detected by the discharge paper end sensor 33 is sandwiched between the paper discharge roller pair 16.

Then, in the next step S17, the computer 41 stops the driving of the transport motor 22, and then proceeds to the next step S18.
In the next step S18, the computer 41 determines whether or not the warp back sensor 34 has detected the preceding paper P1. When the determination result of step S18 is affirmative determination, the computer 41 periodically repeats the determination of step S18. And if the determination result of this step S18 becomes negative determination, the computer 41 will transfer the process to the following step S19.

Then, in the next step S19, the computer 41 drives the transport motor 22, and then shifts the process to the next step S20.
In the next step S20, the computer 41 determines whether or not the last paper P has been discharged. If the determination result of step S20 is affirmative, the computer 41 ends the transport discharge processing routine. On the other hand, when the determination result of step S20 is negative, the computer 41 proceeds to step S13.

As described above, according to the embodiment described in detail, the following effects can be obtained.
(1) Since the succeeding sheet P2 is discharged to the loading unit 17 at a timing for avoiding a collision with the preceding sheet P1 that is warped in the loading unit 17, the discharge of the sheet P2 to the loading unit 17 is performed. It is possible to prevent the sheet P1 in the warped state from being obstructed. Therefore, a plurality of printed sheets P can be continuously and smoothly discharged onto the placement unit 17.

  (2) Since the warp state of the preceding paper P1 discharged to the placement unit 17 by the warp sensor 34 can be detected, the timing at which the placement unit 17 reliably avoids the collision with the paper P1 in the warp state. Thus, the succeeding paper P2 can be discharged to the placement unit 17.

  (3) The succeeding paper P2 is placed on the placement portion 17 when the highest reach of the preceding paper P1 that has been discharged to the placement portion 17 and warped has not reached the height of the discharge port 15 in the placement portion 17. Therefore, the discharge of the paper P2 to the placement unit 17 can be prevented from being hindered by the paper P1 that is warped. For this reason, it is possible to smoothly discharge the paper P2 to the mounting portion 17 without waiting until the warping of the paper P1 discharged to the mounting portion 17 is completely eliminated. This is because the collision of the paper P2 with the paper P1 can be avoided if the highest reachable portion of the paper P1 does not reach the height of the discharge port 15 in the placement unit 17.

  (4) The front end in the transport direction of the succeeding sheet P2 when the highest reaching part of the preceding sheet P1 that has been discharged to the placing unit 17 and warped has reached the height of the discharge port 15 in the placing unit 17. Is held between the discharge roller pair 16 so as not to exit from the discharge port 15. For this reason, it is possible to reliably avoid the collision between the succeeding sheet P2 and the preceding sheet P1 that is warped in the placement unit 17.

(5) The discharge roller pair 16 in the transport path when the highest reached portion of the preceding paper P1 that has been discharged to the placement unit 17 and warped has reached the height of the discharge port 15 in the placement unit 17. The sheet discharge sensor 13 disposed immediately upstream of the sheet discharge sensor 13 conveys the sheet discharge roller 13 at the timing when the front end of the sheet P2 is sandwiched between the discharge roller pair 16 based on the timing at which the front end of the subsequent sheet P2 is detected. The discharging operation is paused. For this reason, at least the front end in the transport direction of the paper P2 can be reliably prevented from coming out of the discharge port 15, so that the subsequent paper P2 collides with the preceding paper P1 that is warped in the loading portion 17. It can be avoided reliably.
(Example of change)
In addition, you may change the said embodiment as follows.

  The time taken from the time when the preceding paper P1 is ejected by the recording head 14 (after printing) until the succeeding paper P2 is discharged to the mounting portion 17 is the paper discharged to the mounting portion 17 The sheet P2 is transported by the transport / discharge device 13 so that the sheet P2 discharged to the loading unit 17 does not collide with the sheet P2 so that the sheet P1 is longer than the time required to improve the warping state of the sheet P1. You may make it the computer 41 control the discharge timing to the mounting part 17. FIG. In this case, the warp back sensor 34 is omitted.

  In this way, when the paper P2 is discharged to the placement unit 17, the curled state of the paper P1 discharged to the placement unit 17 is improved to such an extent that the paper P2 does not collide with the paper P2. Can be prevented from being hindered by the paper P1 in a warped state. Therefore, a plurality of printed sheets P can be continuously and smoothly discharged onto the placement unit 17.

  Further, in the case of this modified example, the computer 41 further stops the transport / discharge operation of the transport / discharge device 13 in a state where the front end of the paper P <b> 2 is sandwiched between the pair of paper discharge rollers 16, and then the transport / discharge device 13. The discharge timing of the paper P2 to the placement unit 17 may be controlled by adjusting the time until the transport and discharge operation of the paper P2 is restarted.

  In this way, since the conveyance of the paper P2 is stopped in a state where the front end of the paper P2 is sandwiched between the paper discharge roller pair 16, it is possible to suppress warping of the front end of the paper P2 during the stop. .

  The warpage return sensor 34 may be disposed at a position lower than the lower end of the discharge port 15 on the left surface 17b of the placement portion 17. However, the height of the warp return sensor 34 in the placement unit 17 needs to be higher than the height of each sheet P when the sheets P are stacked on the placement unit 17 to a predetermined upper limit.

  When the computer 41 determines from the detection result by the warp sensor 34 that the highest arrival position of the preceding sheet P1 has reached the height of the discharge port 15 in the loading unit 17, the conveyance direction of the subsequent sheet P2 is determined. You may make it control the conveyance discharge operation | movement of the conveyance discharge apparatus 13 so that a front end may be located in the upstream rather than the discharge port 15 in a conveyance path | route. That is, when the computer 41 determines that the highest reachable portion of the paper P1 has reached the height of the discharge port 15, the front end in the transport direction of the subsequent paper P2 is positioned upstream of the discharge port 15 in the transport path. As described above, the transport speed of the subsequent paper P2 by the transport / discharge device 13 may be decreased (the transport speed is greater than 0).

  In this way, when the highest reachable portion of the preceding paper P1 that has been discharged to the placement unit 17 and warped has reached the height of the discharge port 15 in the placement unit 17, the subsequent paper P2 is conveyed. Since the front end in the direction is located upstream of the discharge port 15 in the transport path, it is possible to reliably avoid the collision between the paper P2 and the paper P1 that is warped in the placement portion 17.

  Whether or not the rotation amount of the conveyance motor 22 after the printing paper edge sensor 18 detects the front edge of the succeeding paper P2 has reached the threshold value M stored in the nonvolatile memory 47 in step S16 in the conveyance discharge processing routine This may be determined by the computer 41. In this case, the threshold value M is set to a value at which the front end of the paper P <b> 2 whose front end is detected by the printing paper end sensor 18 is sandwiched between the paper discharge roller pair 16. In this way, the paper discharge end sensor 33 can be omitted.

  It may be determined whether or not step S11 in the transport / discharge process routine is the target of the transport / discharge process routine, depending on whether or not the paper P is of a type that tends to curl.

-In a conveyance discharge processing routine, it may be made possible for a user to change arbitrarily whether determination of step S11 and S13 is performed.
Conveyance in which the inkjet printer 11 is provided with a humidity sensor, and when the environmental humidity is low (for example, when the humidity is 30% or less), the conveyance / ejection operation of the subsequent sheet P2 conveyed following the preceding sheet P1 is temporarily stopped. The discharge control may be performed.

-A conveyance path | route may not be provided with the inversion path | route 29a.
The ink jet printer 11 may include a manual feed tray in addition to the paper feed cassette 23, or may include a plurality of paper feed cassettes 23 in a state where a plurality of different types of paper P are mixed. Alternatively, paper feeding may be performed.

  The ink jet printer 11 may be a so-called serial printer in which the recording head ejects ink onto the paper while moving in a scanning direction orthogonal to the paper transport direction.

  In the above embodiment, the liquid ejecting apparatus is embodied in the ink jet printer 11, but a liquid ejecting apparatus that ejects or discharges liquid other than ink may be employed. The present invention can be used for various liquid ejecting apparatuses including a liquid ejecting head that ejects a minute amount of liquid droplets. In addition, a droplet means the state of the liquid discharged from the said liquid ejecting apparatus, and shall also include what pulls a tail in granular shape, tear shape, and thread shape. The liquid here may be any material that can be ejected by the liquid ejecting apparatus. For example, it may be in a state in which the substance is in a liquid phase, such as a liquid with high or low viscosity, sol, gel water, other inorganic solvents, organic solvents, solutions, liquid resins, liquid metals (metal melts ) And a liquid as one state of a substance, as well as a material in which particles of a functional material made of a solid such as a pigment or metal particles are dissolved, dispersed or mixed in a solvent. Further, representative examples of the liquid include ink and liquid crystal as described in the above embodiment. Here, the ink includes general water-based inks and oil-based inks, and various liquid compositions such as gel inks and hot melt inks. As a specific example of the liquid ejecting apparatus, for example, a liquid containing a material such as an electrode material or a color material used for manufacturing a liquid crystal display, an EL (electroluminescence) display, a surface emitting display, or a color filter in a dispersed or dissolved form. It may be a liquid ejecting apparatus for ejecting, a liquid ejecting apparatus for ejecting a bio-organic material used for biochip manufacturing, a liquid ejecting apparatus for ejecting a liquid as a sample used as a precision pipette, a textile printing apparatus, a microdispenser, or the like. In addition, transparent resin liquids such as UV curable resin to form liquid injection devices that pinpoint lubricant oil onto precision machines such as watches and cameras, and micro hemispherical lenses (optical lenses) used in optical communication elements. A liquid ejecting apparatus that ejects a liquid onto the substrate or a liquid ejecting apparatus that ejects an etching solution such as an acid or an alkali to etch the substrate may be employed. The present invention can be applied to any one of these liquid ejecting apparatuses.

  DESCRIPTION OF SYMBOLS 11 ... Inkjet-type printer as a liquid ejecting device, 13 ... Conveying / discharging device as a conveying / discharging means, 14 ... Recording head as a liquid ejecting head, 15 ... Discharge port, 17 ... Placement part, 16 ... Discharging roller pair Paper discharge roller pair 33... Discharged paper edge sensor as edge detecting means 34... Warpage sensor as warping state detection means 41 .. computer as control means P, P 1 to P 3. A preceding sheet as the first medium, P2... A succeeding sheet as the second medium.

Claims (4)

A transport discharge means for continuously transporting a plurality of media along the transport path and discharging the medium from the discharge port to the mounting portion;
A liquid ejecting head that ejects liquid to each medium at a midway position in the transport path;
Control means for controlling the transport discharge operation of the transport discharge means,
The control means, based on the warped state of the first medium as the preceding medium discharged to the placement section, discharge timing of the second medium as the subsequent medium to the placement section by the transport and discharge means. In the liquid ejecting apparatus that controls the timing at which the collision with the first medium in the warped state is avoided ,
The placement unit is provided with a warping state detection means for detecting a warping state of the first medium discharged to the placement unit,
The transport discharge means is provided with a pair of discharge rollers capable of sandwiching each medium upstream of the discharge port in the transport path,
The warped state detecting means detects whether or not the highest reachable part of the first medium in a state of being warped and discharged to the placement unit has reached the height of the discharge port in the placement unit,
When the control means determines from the detection result by the warped state detection means that the highest reach of the first medium has not reached the height of the discharge port in the placement section, the second medium is The transport / discharge operation of the transport / discharge means is controlled so as to be discharged to the placement section, and from the detection result by the warped state detection means, the highest reaching part of the first medium is the height of the discharge port in the placement section. When it is determined that the second medium has been sandwiched between the discharge roller pair so that the front end in the transport direction of the second medium does not exit from the discharge port in the transport path. A liquid ejecting apparatus characterized in that the conveying and discharging operation of the means is stopped . The liquid ejecting apparatus according to claim 1 , further comprising an end detection unit configured to detect a front end in the transport direction of each medium on the upstream side of the discharge roller pair in the transport path. A transport discharge means for continuously transporting a plurality of media along the transport path and discharging the medium from the discharge port to the mounting portion;
A liquid ejecting head that ejects liquid to each medium at a midway position in the transport path;
Control means for controlling the transport discharge operation of the transport discharge means;
With
The control means, based on the warped state of the first medium as the preceding medium discharged to the placement section, discharge timing of the second medium as the subsequent medium to the placement section by the transport and discharge means. In the liquid ejecting apparatus that controls the timing at which the collision with the first medium in the warped state is avoided,
The control means is configured such that a time required from when the first medium is ejected by the liquid ejecting head to when the second medium is ejected to the placement unit is discharged to the placement unit. The transporting and discharging means so as to be longer than the time required to improve the state of warping of the first medium to the extent that the second medium discharged to the placement section does not collide with the first medium. and controlling the discharge timing to the mounting section of said second medium by liquid body ejecting apparatus. The transport discharge means includes a pair of discharge rollers capable of sandwiching each medium upstream of the discharge port in the transport path,
The control means determines a time period from the stop of the transport / discharge operation of the transport / discharge means in a state where the front end of the second medium is sandwiched between the pair of discharge rollers to the restart of the transport / discharge operation of the transport / discharge means. The liquid ejecting apparatus according to claim 3 , wherein the discharge timing of the second medium to the placement unit is controlled by adjusting.

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