JP2012232838A - Liquid ejecting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid ejecting apparatus that prevents quality degradation of a print image by correcting skew or meandering when a long continuous medium is conveyed to a printing position.SOLUTION: X-axis driving units 7c each control acceleration/deceleration of a driving speed of a drive roller 7a disposed on both sides of the medium 4, in accordance with an inclination of the medium 4 with respect to a conveyance direction, so that the inclination of the medium 4 to the conveyance direction is corrected.

Description

  The present invention relates to a liquid ejection apparatus such as an ink jet recording apparatus.

In general, when a long sheet material (web) is fed and wound, a cross guider for removing wrinkles is provided because the sheet material is more easily wrinkled.
For example, the first and third rollers and the second roller (metal roller, resin roller, etc.) are in contact with both ends of the conveyed web so that they are sandwiched from both sides, and the roller axes are arranged to intersect each other. Has been. When the web is viewed in plan, the rotation shafts are arranged so as to intersect in a square shape toward the downstream side in the transport direction. As described above, the rotation axes of the rollers provided at both ends of the web are not parallel but inclined toward the downstream side from the width direction of the web, so that the wrinkles of the film are extended (Patent Document 1). reference).

JP 2009-234713 A

  The cross guider described above is configured to come into contact with both sides at the both ends of the web and perform scooping while being driven and rotated along with the conveyance of the web. If it is, it does not have corrective power.

  In addition, in the ink jet recording apparatus, the printing speed has been increased, and along with this, the conveyance pitch of the long medium in the main scanning direction is about 1/3 inch, but 1 inch or 2 inches. The transport pitch is expanding, and the quality of the printed image is likely to deteriorate if the media skews or meanders in the vicinity of the printing position.

  The object of the present invention is to solve the above-mentioned problems and to prevent the print image from degrading by correcting skewing and meandering when transporting a continuous medium to a printing position. An object of the present invention is to provide a liquid discharge device that can be used.

  In order to solve the above problems, a liquid ejection apparatus according to the present invention has the following configuration. That is, a liquid ejection apparatus comprising: a liquid ejection head that forms a print image on a long belt-like medium; and a conveyance device that continuously conveys the medium to a printing position facing the liquid ejection head, the conveyance apparatus Has a pair of drive parts having at least one drive roller, each of the pair of drive parts being disposed on both sides of the medium in a direction perpendicular to the transport direction of the media, Is driven by the drive roller to convey the medium, and the drive speed of each drive roller can be adjusted by the pair of drive units.

  According to the above configuration, since the driving speed of each driving roller can be adjusted by the pair of driving units, even when the medium is conveyed while being inclined, the driving roller is driven according to the magnitude of the inclination. By varying the speed at both ends of the media, the media tilt can be corrected.

  Further, in the present invention, the pair of driving units are arranged on both sides of the medium in a direction orthogonal to the conveyance direction of the medium, and drive the respective driving rollers. A control unit that controls each of the control units, wherein each control unit corrects the drive speed of the drive roller provided on both sides of the medium according to the tilt with respect to the transport direction of the medium so that the tilt with respect to the transport direction of the medium is corrected As described above, each acceleration / deceleration control is performed.

  According to the above configuration, the drive rollers disposed on both sides of the medium in a direction orthogonal to the medium conveyance direction are corrected by the respective control units according to the inclination with respect to the medium conveyance direction. By performing acceleration / deceleration control as described above, the medium can be conveyed while correcting the inclination with respect to the conveyance direction.

  In the present invention, it further comprises media transport amount detection means for detecting the transport amount of the media by the drive rollers, and the control units correspond to the transport amount of the media detected by the media transport amount detection means. Thus, it is preferable to control the acceleration / deceleration of the driving speed of each of the driving rollers provided on both sides of the medium so as to eliminate the difference in the conveyance amount of the medium.

  According to the above configuration, the media conveyance amount detection means detects the media conveyance amount, and each control unit performs acceleration / deceleration control so that there is no difference in the conveyance amount of the media, so that the drive speed of each drive roller is controlled. The inclination can be corrected with high accuracy.

  In the present invention, a pair of the media conveyance amount detection means is provided on both sides of the medium on the downstream side in the medium conveyance direction with respect to the pair of drive rollers, and each control unit includes the media conveyance amount detection means. It is desirable that feedback control is performed so as to accelerate or decelerate the rotational speed of the corresponding upstream drive roller in accordance with the detected medium conveyance amount.

  According to the above configuration, by detecting the conveyance amount on both sides of the medium in the width direction by the medium conveyance amount detection unit, each control unit performs feedback control to accelerate and decelerate the driving speed of the corresponding upstream drive roller, The skew of the medium can be corrected by detecting the feed unevenness on both sides of the medium in the width direction and controlling the acceleration / deceleration of the rotational speed of the drive roller.

  Further, in the present invention, the conveyance operation of the medium in the main scanning direction by the driving roller and the printing operation by the scanning of the liquid discharge head in the sub-scanning direction are alternately performed at a driving speed commanded in advance by the control unit. When the media transport amount detection means has a difference in the transport amount of the media in the first main scanning direction, the error rate with respect to the drive speed commanded in advance for the second and subsequent drive roller feed amounts It is also possible to perform feedback control so as to make adjustments in consideration of the above. As a result, it is possible to correct and transport the non-uniformity of media feeding caused by the media transport operation for each time in the next transport operation, and to correct skewing and meandering of the media.

Alternatively, the operation of conveying the medium in the main scanning direction by the drive roller and the printing operation by scanning in the sub-scanning direction of the liquid discharge head are alternately performed at the driving speed commanded in advance by the control unit, Feedback control may be performed by changing the driving speed of the driving rollers on both sides in small increments so that the total feed amount of the medium detected by the transport amount detection means becomes equal.
In this case, the actual media feed amount detected by the media transport amount detection means is detected by the media transport amount detection means, based on the individual difference of each drive roller that is rotationally driven based on the drive command output to each drive roller by the control unit. By monitoring this and making it equal on both sides, it is possible to transport while correcting skew and meandering of the media.

  According to the present invention, it is possible to prevent the quality of a printed image from being deteriorated by correcting skewing and meandering when a long continuous medium is conveyed to a printing position.

It is a schematic diagram of an inkjet recording device. It is explanatory drawing which shows a conveying apparatus and its control operation. It is explanatory drawing which shows the conveying apparatus which concerns on another example, and its control operation.

  Hereinafter, embodiments of a cleaning device and a liquid ejection device using the same according to the present invention will be described in detail with reference to the drawings. Hereinafter, as an example of the liquid ejecting apparatus, an ink jet recording apparatus will be described with respect to an ink jet recording apparatus cleaning apparatus. The main scanning direction indicates the direction in which the carriage reciprocates (Y-axis direction), and the sub-scanning direction indicates the medium (medium) transport direction (X-axis direction) orthogonal to the main scanning direction.

  FIG. 1 is a perspective view showing the appearance of the ink jet recording apparatus. As shown in the figure, the inkjet recording apparatus 1 uses, for example, a large and long roll sheet (in this embodiment, a long cloth or cloth in a belt shape) as a medium (printing medium). The media 4 fed from the feeding roll 3 wound around the feeding shaft 2 is conveyed to the platen 6 through the upstream tension bar 5.

  The platen 6 is provided with a transport device 7, and the medium 4 is transported by the transport device 7 to a printing position facing the ejection head 8 in the main scanning direction. The ejection head 8 is mounted on a carriage 9, and the carriage 9 is provided so as to be able to reciprocate along a Y-axis direction support member (Y bar) 10 provided in the sub-scanning direction (media width direction). . Printing is performed by ejecting ink liquid onto the medium 4 while the carriage 9 moves in the sub-scanning direction. When printing is performed, the medium 4 is sent by the conveying device 7 in the main scanning direction, and the carriage 9 is moved. The next printing operation is started after scanning.

The platen 6 facing the ejection head 8 may be provided with an ink receiving groove (not shown) because the ink is transmitted (back through) in the case of cloth media.
Further, the platen 6 that guides the conveyance while supporting the medium 4 may be provided with a heater for improving the fixing property of the ink.

  The medium 4 after printing is sent downstream by a tension roller 11, and is wound as a winding roll 14 on a winding shaft 13 through a downstream tension bar 12.

  As shown in FIG. 2, the transport device 7 includes a pair of drive units having drive rollers 7 a disposed on both sides of the medium 4 in a direction orthogonal to the transport direction of the medium 4. The driving roller 7 a is provided in contact with the back side of the medium 4. As the drive roller 7a, a spike roller having a metal piece projected on the surface by cutting is suitably used for cloth media. When the medium 4 is a resin sheet, a resin roller or the like may be used. Moreover, you may have a driven roller which pinches | interposes the drive roller 7a and the medium 4. FIG.

  The rotation shaft 7 b of each drive roller 7 a is provided along the width direction of the medium 4. The rotary shaft 7b is rotationally driven by an X-axis drive unit 7c (control unit) having a drive source. The rotary shaft 7b is provided with a rotary encoder 7d, and the feed amount (drive pulse) of the drive roller 7a is detected and input to the X-axis drive unit 7c. The X-axis drive unit 7c is provided with a motor that rotates the drive roller 7a, a motor drive circuit that controls the drive, an arithmetic circuit that calculates the rotational speed of the drive roller 7a, and a control circuit that outputs a command. .

  A pair of media encoders 7e (media transport amount detection means) are provided on both sides of the media 4 on the downstream side of the drive roller 7a in the media transport direction. Each media encoder 7e detects the transport amount of the media 4, and a detection signal is input to the X-axis drive unit 7c provided on the upstream side.

The X-axis drive unit 7c compares the detection signal (detection pulse) of the rotary encoder 7d with the detection signal (detection pulse) of the media encoder 7e, so that the medium 4 is conveyed along the conveyance direction (in the parallel direction). It is possible to know the conveyance state whether the medium 4 is tilted in the width direction of the medium 4.
The X-axis drive unit 7c performs acceleration / deceleration control (feedback control) so that the drive speed of the drive roller 7a provided on both sides of the medium 4 is corrected according to the inclination of the medium 4 with respect to the conveyance direction. )

  Specifically, in FIG. 2, the conveying operation in the main scanning direction of the medium 4 by the driving roller 7a and the printing operation by scanning in the sub-scanning direction of the discharge head 8 at the driving speed commanded in advance from the X-axis driving unit 7c. Are performed alternately. At this time, if there is a difference in the transport amount of the medium 4 in the first main scanning direction in the media encoder 7e, the error rate of the second and subsequent drive rollers 7a with respect to the drive speed commanded in advance is taken into account. Feedback control to adjust. A specific example will be described below.

  For example, in FIG. 2, in the first conveyance of the medium 4, it is assumed that 100 pulses are output from the left and right X-axis drive units 7c and measured by the rotary encoder 7d. On the other hand, assume that 80 pulses are detected on the left side and 120 pulses are detected on the right side in each media encoder 7e provided downstream of the left and right drive rollers 7a.

  In the second transport operation of the medium 4, the X-axis drive unit 7 c controls the rotation of the drive roller 7 a through a motor so that there is no difference in the transport amount of the medium 4. That is, theoretically, the left and right drive rollers 7a are each driven to rotate at 100 pulses, while the left drive roller 7a is driven to rotate at 100 × (100/80) = 125 pulses, and the right drive roller 7a is rotated 100 × (100 / 120) = Rotation drive with 83 pulses. That is, when a difference (transport error) occurs in the transport amount of the medium 4 due to the individual difference between the left and right drive rollers 7a, a correction pulse is calculated by feedback control of the error rate. As a result, it is possible to correct the transport irregularity of the media 4 caused by the transport operation of the media 4 every time and to transport the media 4 by correcting the next transport operation, and to correct the skew and meandering of the media 4.

Next, a control operation according to another example of the transport device 7 will be described with reference to FIG.
FIG. 2 shows that the conveyance operation in the main scanning direction of the medium 4 by the driving roller 7a and the printing operation by scanning in the sub-scanning direction of the ejection head 8 are alternately performed at a driving speed commanded in advance from the X-axis driving unit 7c. It is the same. In this embodiment, the drive pulse is divided and output from the X-axis drive unit 7c so that the drive speed by the drive rollers 7a on both sides changes in small increments, and the actual media conveyance amount detected by the media encoder 7e is fed back. The feeding operation is performed while feedback control is performed so that the total feed amount of the media 4 detected by the media encoder 7e is equal on both sides. A specific example will be described below.

In FIG. 3, it is assumed that drive pulses for the left and right drive rollers 7a are output as commands from the X-axis drive unit 7c, and the feed amount of the media 4 is determined to be 100 pulses in total on both sides.
The X-axis drive unit 7c first outputs the left drive roller 7a by dividing the first drive pulse by 80 pulses. At this time, it is assumed that the media encoder 7e detects 75 pulses.
Next, 20 drive pulses of the second drive roller 7a are divided and output. At this time, it is assumed that the media encoder 7e detects 18 pulses.
Next, the third drive pulse of the drive roller 7a is divided and output by 5 pulses. At this time, it is assumed that the media encoder 7e detects four pulses.
Next, the drive pulse of the fourth drive roller 7a is divided and output by 3 pulses. At this time, it is assumed that the media encoder 7e detects two pulses.
Further, the drive pulse of the fifth drive roller 7a is divided and output by one pulse. At this time, it is assumed that the media encoder 7e detects one pulse.
As described above, the total number of output pulses by the drive command from the X-axis drive unit 7c is 109 pulses and exceeds 100 pulses, but the actual feed amount (feed amount) of the media 4 detected by the media encoder 7e is 100 pulses. It becomes.

The X-axis drive unit 7c first splits and outputs the first drive pulse of the right drive roller 7a by 80 pulses. At this time, it is assumed that the media encoder 7e detects 85 pulses.
Next, the drive pulse of the second drive roller 7a is divided and output only by 10 pulses. At this time, it is assumed that the media encoder 7e detects 11 pulses.
Next, the third drive roller 7a drive pulse is divided and output by two pulses. At this time, it is assumed that the media encoder 7e detects two pulses.
Further, the drive pulse of the fourth drive roller 7a is divided and output by two pulses. At this time, it is assumed that the media encoder 7e detects two pulses.
As described above, the total number of output pulses based on the drive command from the X-axis drive unit 7c is 94 pulses, which is less than 100 pulses, but the actual feed amount (feed amount) of the media 4 detected by the media encoder 7e is 100. It becomes a pulse.
The first drive pulse of the left and right drive rollers 7a output from the X-axis drive unit 7c is not limited to 80 pulses, and may be 70 pulses or 90 pulses.

In this way, when there is an individual difference in the actual feed amount compared to the drive pulse output from the X-axis drive unit 7c in the left and right drive rollers 7a, the actual media detected by such a media encoder 7e. It is desirable to drive-control the X-axis drive unit 7c so that the feed amount 4 is equal on the left and right.
As a result, the feed unevenness based on the individual difference of each drive roller 7a that is rotationally driven based on the drive command output to each drive roller 7a by the X-axis drive unit 7c is detected by the media encoder 7e. By monitoring the feed amount and making it equal on both sides, the medium 4 can be conveyed while correcting skew and meandering.

  DESCRIPTION OF SYMBOLS 1 Inkjet recording device 2 Feeding shaft 3 Feeding roll 4 Media 5 Upstream tension bar 6 Platen 7 Conveying device 7a Drive roller 7b Rotating shaft 7c X-axis drive part 7d Rotary encoder 7e Media encoder 8 Discharge head 9 Carriage 10 Y-axis direction support member 11 Tension roller 12 Downstream tension bar 13 Winding shaft 14 Winding roll

Claims (6)

A liquid ejection apparatus comprising: a liquid ejection head that forms a print image on a long belt-like medium; and a conveyance device that continuously conveys the medium to a printing position facing the liquid ejection head,
The transport device includes a pair of drive units having at least one drive roller, and the pair of drive units is disposed on both sides of the medium in a direction perpendicular to the transport direction of the medium, A liquid ejecting apparatus, wherein the medium is conveyed by driving both ends of the medium by the driving roller, and the driving speed of each driving roller can be adjusted by the pair of driving units.   The pair of drive units is a direction perpendicular to the conveyance direction of the medium and disposed on both sides of the medium, a drive roller that conveys the medium, and a control unit that controls driving of each of the drive rollers, And each of the control units accelerates / decelerates the driving speed of the driving roller provided on both sides of the medium according to the inclination with respect to the conveyance direction of the medium so that the inclination with respect to the conveyance direction of the medium is corrected. The liquid ejecting apparatus according to claim 1 to be controlled.   Media transport amount detection means for detecting the transport amount of the media by the drive rollers is provided, and the control units are provided on both sides of the media according to the transport amount of the media detected by the media transport amount detection means. The liquid ejection apparatus according to claim 1, wherein the drive speed of each of the drive rollers is controlled to be accelerated or decelerated so that a difference in the transport amount of the medium is eliminated.   The media transport amount detection means is provided in a pair on both sides of the media on the downstream side in the media transport direction from the pair of drive rollers, and each control unit detects the media transport amount detected by the media transport amount detection means. 4. The liquid ejection device according to claim 1, wherein feedback control is performed so as to accelerate and decelerate the rotation speed of the corresponding upstream drive roller in accordance with.   The medium conveying amount is alternately performed by the driving roller in the main scanning direction by the driving roller and the printing operation by scanning the liquid ejection head in the sub-scanning direction at a driving speed commanded in advance by the control unit. When there is a difference in the transport amount of the medium in the first main scanning direction in the detection means, the feed amount of the drive roller after the second time is adjusted in consideration of the error ratio with the drive speed commanded in advance. The liquid ejection apparatus according to claim 1, wherein feedback control is performed.   The medium conveying amount is alternately performed by the driving roller in the main scanning direction by the driving roller and the printing operation by scanning the liquid ejection head in the sub-scanning direction at a driving speed commanded in advance by the control unit. 5. The feedback control according to claim 1, wherein the drive speed of the drive rollers on both sides is divided and changed in small increments so that the total feed amount of the medium detected by the detection means becomes equal. The liquid discharge apparatus according to any one of the preceding claims.

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