JP2010162724A - Recording position correcting apparatus and recording apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that, when the position of a line head adjusted is shifted due to vibration, change in temperature or the like of an inkjet printer during printing, the position of printing on a paper is shifted. <P>SOLUTION: A recording position correcting apparatus includes: head units 10 and 20 for printing on a paper P conveyed on a conveying face 50; and mark sensors S11, S12 and S13 for detecting marks M1 and M2 for correcting the position printed on the paper P. In addition, the apparatus further includes a head position information calculating part 93 for calculating head position information showing a positional shifting condition regarding the position where the head units 10 and 20 print a paper P behind one sheet to the paper P, when a position where the head units 10 and 20 print the paper P is made as an appropriate position. Furthermore, it includes a controlling part 90 for moving the head units 10 and 20 in the direction parallel to the conveying face 50 based on the head position information. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a recording position correction apparatus and a recording apparatus.

  2. Description of the Related Art Conventionally, various techniques have been proposed for recording at an accurate position on a recording medium in a recording apparatus such as an ink jet printer or a laser beam printer. For example, in the misalignment correction apparatus for an ink jet printer described in Patent Document 1 below, an alignment adjustment mechanism that enables the line head to rotate is provided, and the optical path of the laser beam is changed to a reference optical path by a method such as the method of using the line head. Alignment adjustment is performed. And by this alignment adjustment, for example, the production efficiency of the ink jet printer is improved, and effects such as quick readjustment of the line head when the head module is replaced are obtained.

JP 2008-12712 A

  However, the misregistration correction apparatus as described in Patent Document 1 described above is an alignment adjustment performed on the line head before printing on a sheet. For this reason, during printing, if the position of the adjusted line head is shifted due to vibration of the ink jet printer, temperature change, or the like, the printing position on the paper may be shifted. Further, when readjustment of the line head is performed with respect to such a displacement of the printing position, the printing cost is increased due to a decrease in printing throughput and an increase in waste paper.

  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]
A recording position correction apparatus according to this application example includes a head unit that records by ejecting liquid onto a recording medium that is transported on a transport surface, and a mark detection unit that detects a position correction mark recorded on the recording medium. And when recording on the recording medium after the one recording medium, when the position of the head unit when recording on the one recording medium is an appropriate position where the head unit should be positioned About the position of the head unit, a head position information calculation unit that calculates head position information indicating a misalignment state with respect to the appropriate position, and a direction parallel to the transport surface based on the head position information And a controller that positions the head unit at the appropriate position.

According to this recording position correction apparatus, the mark detection unit detects the position correction mark recorded on the recording medium. Then, the head position information calculation unit sets the position of the head unit when recording on one recording medium to an appropriate position, and the head unit when recording on a recording medium after this is relative to the appropriate position. Head position information indicating the misalignment state is calculated. And based on this head position information, a control part moves a head unit in the direction parallel to a conveyance surface.
As a result, it is possible to grasp the position of the head unit when recording on one recording medium and the positional deviation of the head unit when recording on a recording medium after this. Corrections can be made to match the position of the head unit when recording on the recording medium. As a result, for example, when the adjusted head unit is displaced due to vibration, temperature change, or the like, the displacement can be corrected during printing and recorded at an accurate position on the recording medium.

[Application Example 2]
In the recording position correction apparatus according to the application example, the head position information includes a displacement amount from the appropriate position in a direction orthogonal to the conveyance direction of the recording medium, and the control unit is based on the displacement amount. It is desirable to move the head unit.

  According to this recording position correction apparatus, the control unit can move the head unit based on the amount of positional deviation from the appropriate position included in the head position information. As a result, when the head unit is displaced from the proper position, the displacement can be corrected by moving the head unit.

[Application Example 3]
In the recording position correction apparatus according to the application example, the head position information includes a skew amount with respect to the head unit located at the appropriate position, and the control unit is configured to It is desirable to rotate the head unit around an axis perpendicular to the transport surface.

  According to this recording position correction apparatus, the control unit can rotate the head unit around an axis in a direction perpendicular to the conveyance surface based on the skew amount from the appropriate position included in the head position information. Accordingly, when the head unit is skewed from an appropriate position, the skew can be corrected by the rotation of the head unit.

[Application Example 4]
In the recording position correction apparatus according to the application example described above, the control unit causes the head unit to be parallel to the transport surface only when the position shift state indicated by the head position information is larger than a predetermined position shift allowable value. It is desirable to move in any direction.

  According to this recording position correction apparatus, the control unit moves the head unit only when the positional deviation state is larger than the predetermined positional deviation allowable value, and thus corrects the head unit according to the degree of positional deviation. It can be performed.

[Application Example 5]
In the recording position correction apparatus according to the application example, it is preferable that the position correction mark is recorded on a cutting portion of the recording medium.

  According to this recording position correction apparatus, since the position correction mark is recorded on the cutting portion of the recording medium, it is possible to remove the position correction mark unnecessary for the user who browses the recorded contents of the recording medium.

[Application Example 6]
In the recording position correction apparatus according to the application example, it is preferable that a plurality of the position correction marks are recorded in the width direction of the recording medium, and a plurality of the mark detection units are arranged in the width direction of the recording medium. .

  According to this recording position correction apparatus, a plurality of position correction marks are recorded in the width direction of the recording medium, and a plurality of mark detection units are arranged in the width direction of the recording medium. Can be calculated.

[Application Example 7]
In the recording position correction apparatus according to the application example, it is preferable that the mark detection unit moves according to the size of the recording medium.

  According to this recording position correcting apparatus, when recording is performed on recording media of various sizes, the mark detection unit can be accommodated by moving according to the size of the recording medium.

[Application Example 8]
In the recording position correction apparatus according to the application example, a recording medium detection unit that detects a position of the recording medium to be conveyed, and conveyance information that indicates a conveyance state of the recording medium based on the detected position of the recording medium. A transport information calculating unit that calculates the information, and the control unit moves the head unit in a direction parallel to the transport surface to a position corresponding to the transport information based on the transport information. desirable.

According to this recording position correction apparatus, the conveyance information calculation unit calculates conveyance information indicating the conveyance state of the recording medium based on the position of the recording medium detected by the recording medium detection unit. And a control part moves a head unit to the direction parallel to a conveyance surface based on this conveyance information.
Since the head unit is moved based on the conveyance information of the recording medium, when the relative position between the recording medium being conveyed and the head unit is not constant, the head unit is moved according to the conveyance information, and the relative position Can be made constant. As a result, during recording on the recording medium, an image can be formed on the intended portion of the recording medium from the head unit.

[Application Example 9]
In the recording position correction apparatus according to the application example described above, the transport information includes a positional deviation amount from a predetermined reference position in the width direction of the recording medium, and the control unit is configured to control the head based on the positional deviation amount. It is desirable to move the unit.

  According to this recording position correcting apparatus, the control unit can move the head unit based on the positional deviation amount in the width direction of the recording medium included in the conveyance information. Thereby, when a positional deviation occurs in the recording medium, the positional deviation can be dealt with by the movement of the head unit.

[Application Example 10]
In the recording position correction apparatus according to the application example, the transport information includes a skew amount of the recording medium, and the control unit moves the head unit in a direction perpendicular to the transport surface based on the skew amount. It is desirable to rotate around the axis.

  According to this recording position correction apparatus, the control unit can rotate the head unit around an axis in a direction perpendicular to the conveyance surface based on the skew amount included in the conveyance information. Thereby, when skew occurs in the recording medium, the skew can be dealt with by rotation of the head unit.

[Application Example 11]
A recording apparatus according to this application example includes the recording position correction apparatus described above, and performs recording on a recording medium.

  According to this recording apparatus, when a positional deviation occurs with respect to an appropriate position where the head unit should be positioned, the head unit can be moved and corrected so as to be positioned at the appropriate position. Thereby, it is possible to record at an accurate position of the recording medium from the head unit.

(First embodiment)
Hereinafter, as an example of a recording apparatus that includes a recording position correction apparatus and performs recording on a recording medium, an inkjet according to the first embodiment that prints an image or the like on a recording medium such as paper by ejecting (discharging) a liquid such as ink. The printer will be described. The ink jet printer here includes two head units in which a plurality of ink jet heads (ejection heads) are arranged in a direction intersecting the paper transport direction, and is a line head type ink jet printer capable of printing in a so-called one pass. It is.

  FIG. 1 is a side sectional view schematically showing an outline of the ink jet printer 100 according to the first embodiment. FIG. 2 is a plan view schematically showing the outline of the inkjet printer 100. Inside the inkjet printer 100 shown in FIG. 1 and FIG. 2, a transport unit 1 that holds and transports the paper P to be printed, and printing that performs printing on the paper P held and transported by the transport unit 1. Part 2 is provided. The operations of the transport unit 1 and the printing unit 2 are controlled by a control unit 90 shown in FIG. In the following description, the normal transport direction of the paper P in the ink jet printer 100 is referred to as a transport direction X, and the direction orthogonal to the transport direction X is referred to as a transport width direction Y.

  The conveyance unit 1 includes a gate roller 31 constituted by a pair of upper and lower nip rollers shown in FIG. 1, a driven roller 32 disposed on the upstream side in the conveyance direction X, and a drive roller disposed on the downstream side in the conveyance direction X. 34, a tension roller 33 disposed below the driven roller 32 and the drive roller 34, an endless belt 35 that winds between the three rollers 32, 33, and 34 in a loop.

  The drive roller 34 is a roller for applying a transport force in the transport direction X to the endless belt 35. As shown in FIG. 2, a conveyance drive motor 36 for transmitting power to the drive roller 34 is directly connected to one end in the conveyance width direction Y. On the other hand, the driven roller 32 is a roller having the same height as that of the driving roller 34 and arranged to face each other in parallel at a certain distance.

  The endless belt 35 is an endless belt-shaped member formed of a material having elasticity such as a synthetic rubber or a resin film. As shown in FIG. 2, the endless belt 35 has a large number of air holes 37 formed therein. The suction and holding action of the paper P by a suction device (not shown) is executed through the vent hole 37 so that the paper P is sucked and held on the transport surface 50 of the endless belt 35 that transports the paper P. Here, as a suction method of the suction device, for example, suction by negative pressure or electrostatic suction can be employed.

  On the other hand, the printing unit 2 includes a head unit 10 disposed on the upstream side in the transport direction X, a head unit 20 disposed on the downstream side, and the like. As shown in FIG. 2, each head unit 10, 20 includes a plurality of ejection heads 11 that eject ink droplets in each head panel 12. These ejection heads 11 are divided (separated) in the transport direction X by each of the head units 10 and 20, and four are arranged in the head unit 10 row and three in the head unit 20 row. The ejection heads 11 in each row are also divided (separated) in the transport width direction Y so that the entire ejection heads 11 are staggered in plan view, that is, transported along the transport width direction Y. They are alternately arranged upstream and downstream in the direction X.

The head units 10 and 20 can be reciprocated in the transport width direction Y that is parallel to the transport surface 50. Further, each of the head units 10 and 20 can be rotated clockwise and counterclockwise around an axis in a direction perpendicular to the conveyance surface 50 around the θ rotation shaft 13. That is, each head unit 10, 20 can be rotated in a direction parallel to the transport surface 50.
Details of the reciprocation and rotation of the head units 10 and 20 will be described later.

FIG. 3 is an explanatory diagram of the arrangement of the ejection heads 11 and is a view of the head units 10 and 20 as viewed from below. As shown in the figure, on the surface (nozzle surface) of each ejection head 11 facing the transport surface 50, a number of nozzles that eject ink droplets are formed.
Specifically, on each nozzle surface, four rows of nozzle rows composed of a plurality of nozzles arranged along the transport width direction Y are formed apart from each other in the transport direction X. These four nozzle arrays can eject inks of different colors. In this embodiment, black (K), cyan (C), magenta (M), yellow are sequentially arranged from the upstream side in the transport direction X. (Y) ink is ejected.

  In addition, each discharge head 11 is superposed in the transport direction X with the nozzle at the transport width direction Y end of the adjacent discharge head 11 that is spaced apart in the transport direction X or the opposite direction. It is arranged. Then, for each color, that is, for each nozzle row, a necessary amount of ink droplets are simultaneously ejected from the nozzles at the necessary locations, thereby forming minute ink dots on the paper P. The ink jet printer 100 repeats this operation while transporting the paper P in the transport direction X. Then, only by sending the paper P in the transport direction X in one pass, an image having a width corresponding to the distance between the nozzles at both ends in the transport width direction Y of the head units 10 and 20 can be printed.

The method for ejecting ink from the nozzles is not limited to a specific method, and various methods such as an electrostatic method, a piezo method, and a film boiling ink jet method can be employed.
The electrostatic method is a method in which a drive pulse is applied to the electrostatic gap to displace the diaphragm in the cavity, and ink droplets are ejected by a pressure change in the cavity caused by the displacement. The piezo method is a method in which a drive pulse is applied to a piezo element to displace a diaphragm in a cavity, and ink droplets are ejected by a pressure change in the cavity caused by the displacement. The film boiling ink jet method is a method in which ink is heated by a micro heater provided in a cavity, and ink droplets are ejected by a pressure change accompanying generation of bubbles.

FIG. 4 is an explanatory diagram of the mechanism and operation related to the reciprocating movement and rotation of the head unit 10. The head unit 10 shown in the figure includes a Y-axis motor 14 for transmitting power for reciprocating the head panel 12 in the transport width direction Y, a slide rail (not shown) extending along the transport width direction Y, and a head. A θ-axis motor 15 that transmits power for rotating the panel 12 around the θ-rotating shaft 13 is attached. As with the head unit 10, the head unit 20 is also provided with a Y-axis motor 14, a slide rail, and a θ-axis motor 15. The head unit 20 can be reciprocated in the transport width direction Y and rotated about the θ rotation shaft 13.
In this embodiment, as the Y-axis motor 14 and the θ-axis motor 15 attached to the head units 10 and 20, for example, a linear ultrasonic motor capable of controlling a minute displacement is used.

  4A shows an example in which the head unit 10 is moved by Ya in the transport width direction Y from the reference position in the transport width direction Y. FIG. Here, based on the control of the control unit 90, the Y-axis motor 14 is driven, and the head unit 10 can be moved by Ya in the transport width direction Y according to the slide rail so as to be in the position of the broken line portion.

  FIG. 4B shows an example in which the head unit 10 is rotated clockwise from the reference position by the angle θa about the θ rotation shaft 13. Here, based on the control of the control unit 90, the θ-axis motor 15 is driven, and the head unit 10 is rotated clockwise about the θ rotation shaft 13 by an angle θa to the position of the broken line portion. be able to.

Here, as a combination of FIGS. 4A and 4B, the Y-axis motor 14 is driven to move the head panel 12 in the transport width direction Y, and then the θ-axis motor 15 is driven to The panel 12 can be rotated about the θ rotation axis 13. Conversely, the θ-axis motor 15 is driven to rotate the head panel 12 around the θ-rotation shaft 13, and then the Y-axis motor 14 is driven to move the head panel 12 in the transport width direction Y. You may make it let it. Alternatively, the head panel 12 may be moved and rotated in the transport width direction Y at the same time.
Note that the positions of the θ rotation shaft 13, the Y axis motor 14, and the θ axis motor 15 are not limited to the positions shown in FIG.

  Referring back to FIGS. 1 and 2, two edge sensors S1 and S2 are disposed on the upstream side in the transport direction X across the head unit 10, and two edge sensors S3 and S4 are disposed on the downstream side. Two edge sensors S5 and S6 are arranged on the upstream side in the transport direction X across the head unit 20, and two edge sensors S7 and S8 are arranged on the downstream side. Further, two mark sensors S11 and S12 are arranged on the further downstream side of the edge sensor S8 so as to be separated from each other in the transport width direction Y, and one mark sensor is adjacent to the downstream side of the mark sensor S11. S13 is arranged.

  Here, the edge sensors S1 to S8 are sensors as a recording medium detection unit that detects the position of the end portion in the width direction of the paper P, and the mark sensors S11 to S13 are positions correction marks printed on the paper P. It is a sensor as a mark detection unit that detects a position. The edge sensors S1 to S8 and the mark sensors S11 to S13 are, for example, reflective image sensors having a structure in which a light emitting element and a light receiving element face the direction of the conveyance surface 50.

The edge sensors S1 to S8 and the mark sensors S11 to S13 irradiate light from the light emitting elements in the direction of the conveyance surface 50, and receive reflected light by a plurality of light receiving elements, whereby the edge of the paper P on the conveyance surface 50 in the width direction The position of the part and the position of the position correction mark printed on the paper P can be detected. In the present embodiment, for example, a CCD image sensor or a CMOS image sensor is used as the edge sensors S1 to S8 and the mark sensors S11 to S13.
In addition, the edge sensors S1 to S8 and the mark sensors S11 to S13 are automatically moved to positions where the width direction end of the paper P and the position correction mark can be detected according to the size of the paper P in the width direction. You may make it do.

  Note that the number and arrangement positions of the edge sensors and mark sensors to be arranged are not limited to the above. For example, the position of the paper P is detected by arranging only one edge sensor or three or more edge sensors on the upstream and downstream sides of each head unit 10 and 20. You may make it do. Alternatively, the edge sensor may be disposed only on either the upstream side or the downstream side of the head units 10 and 20. Further, a mark sensor for detecting each position correction mark may be provided according to the number and position of the position correction marks printed on the paper P.

  A control unit 90 shown in FIG. 2 includes a CPU, a ROM, a RAM, and the like (not shown), and controls each unit and each mechanism in the inkjet printer 100. The control unit 90 includes a conveyance information calculation unit 91, a first movement amount calculation unit 92, a head position information calculation unit 93, a second movement amount calculation unit 94, and the like.

The conveyance information calculation unit 91 calculates conveyance information indicating the conveyance state of the paper P on the conveyance surface 50. This conveyance information includes the positional deviation amount and skew amount of the paper P. The positional deviation amount and the skew amount are calculated based on the position of the edge in the width direction of the paper P detected by the edge sensors S1 to S8 when the paper P is transported on the transport surface 50.
Here, the misregistration amount is a misregistration amount from a predetermined reference position in the conveyance width direction Y of the paper P, and represents an interval from the reference position to the position of the end portion in the width direction of the paper P. . Further, the skew amount represents the amount of inclination of the end portion in the width direction of the paper P with respect to the transport direction X.

  Next, the first movement amount calculation unit 92 performs the width direction movement that becomes the movement amount in the conveyance width direction Y for each of the head units 10 and 20 based on the positional deviation amount of the paper P calculated by the conveyance information calculation unit 91. Calculate the amount. Further, the first movement amount calculation unit 92 calculates the rotation amount around the θ rotation axis 13 for each of the head units 10 and 20 based on the calculated skew amount of the paper P.

Here, the amount of movement in the width direction calculated by the first movement amount calculation unit 92 is, for example, when the positional deviation occurs in the paper P that passes under the head units 10 and 20. , 20 are moved in the same direction as the positional deviation, thereby obtaining a movement amount corresponding to the positional deviation.
In addition, the rotation amount calculated by the first movement amount calculation unit 92 is, for example, the value obtained when each head unit 10, 20 is skewed when the sheet P passing under each head unit 10, 20 is skewed. By rotating to match the inclination of the skew, the rotation amount corresponds to the skew. That is, the rotation amount for making each head unit 10, 20 orthogonal to the width direction end portion of the paper P passing under each head unit 10, 20 is calculated.

  Next, the head position information calculation unit 93 calculates head position information indicating the current positional deviation state of the head units 10 and 20 with respect to an appropriate position where the head units 10 and 20 should be positioned. This head position information includes the positional deviation amount from the appropriate position in the transport width direction Y and the skew amount with respect to the appropriate position for each of the head units 10 and 20.

Here, in the present embodiment, the proper positions where the head units 10 and 20 should be positioned are the head units 10 when printing on the first sheet P when printing on a plurality of sheets P. , 20 is an appropriate position. The positional deviation amount and the skew amount of each head unit 10, 20 calculated when printing on each of the second and subsequent sheets of paper P are the respective head units 10 when printing on the first sheet of paper P. , 20 and the amount of displacement compared with the position of 20 as a reference.
Note that the proper positions where the head units 10 and 20 should be positioned are not limited to the positions of the head units 10 and 20 when the first sheet P is printed. It may be the position of each head unit 10, 20 when printing is performed, or may be a specified value that defines an appropriate position where each head unit 10, 20 should be positioned.

Further, the positional deviation amount and the skew amount of each head unit 10, 20 are calculated based on the position of the position correction mark on the paper P detected by the mark sensors S11 to S13 after the paper P is printed. The The position correction mark is printed on the paper P from the head units 10 and 20 together with the print image.
FIG. 5 is a plan view showing an example of the position correction marks M1 and M2 printed on the paper P by the inkjet printer 100. FIG. FIG. 6 is an explanatory diagram for calculating the positional deviation amount of the head unit 10 from the position correction mark M1 of the paper P. FIG. 7 shows the skew amount of the head unit 10 from the position correction marks M1 and M2 of the paper P. It is explanatory drawing which calculates. 5 to 7 show examples in which two cross-shaped position correction marks M1 and M2 are printed together with the print image G by the head unit 10, but the same applies to the head unit 20. be able to. When the position correction marks are printed from both the head units 10 and 20, a total of four position correction marks are printed.
The shape of the position correction mark is not limited to a cross shape, and various shapes such as a single character shape, a T-shape, an L-shape, a quadrangle, a triangle, and a circle may be used. When cutting the edge of the paper P after printing, for example, as shown in FIGS. 5 to 7, the position correction mark is placed near the edge in the width direction of the leading edge of the paper P, that is, an unnecessary cutting portion. It is preferable to print.

  The positional deviation amount of the head unit 10 shown in FIG. 5 is calculated based on the position of the position correction mark M1 of the paper P detected by the mark sensor S13. Specifically, the mark sensor S13 detects a horizontal line X1 portion extending in the cross-shaped transport direction X forming the position correction mark M1 shown in FIG. Then, as shown in the density detection result a in FIG. 6, the interval from the position of the image density indicating the edge in the width direction of the paper P to the position where the image density becomes the highest is the horizontal line X1 from the edge in the width direction of the paper P. It becomes the distance Ka to the part. By comparing the distance Ka with reference to the distance Ka when printing on the first sheet P, the positional deviation amount of the head unit 10 can be calculated.

  The skew amount of the head unit 10 is calculated based on the positions of the position correction marks M1 and M2 of the paper P detected by the mark sensors S11 and S12. Specifically, the vertical line Y1 portion extending in the conveyance width direction Y of the cruciform forming the position correction mark M1 shown in FIG. 7 is detected by the mark sensor S11 to form the cruciform forming the position correction mark M2. A vertical line Y2 portion extending in the transport width direction Y is detected by the mark sensor S12. Then, as shown in the density detection result b of FIG. 7, the interval from the position of the image density indicating the leading end portion of the sheet P to the position where the image density becomes the highest with respect to the position correction mark M1 is from the leading end portion of the sheet P. The distance Kb to the vertical line Y1 portion, and as shown in the density detection result c, the distance from the position of the image density indicating the leading end of the sheet P to the position where the image density is highest for the position correction mark M2 is the sheet. This is the distance Kc from the tip of P to the vertical line Y2. By comparing the angle θk formed by the difference between the distance Kb and the distance Kc with reference to the angle θk when printing on the first sheet P, the skew amount of the head unit 10 can be calculated.

  Next, the second movement amount calculation unit 94 uses the displacement amount from the appropriate position of each head unit 10, 20 calculated by the head position information calculation unit 93 for the head units 10, 20 in the conveyance width direction. The amount of movement in the width direction that is the amount of movement of Y is calculated. Further, the second movement amount calculation unit 94 calculates a rotation amount around the θ rotation axis 13 for each head unit 10, 20 based on the calculated skew amount of each head unit 10, 20.

  Here, the movement amount in the width direction calculated by the second movement amount calculation unit 94 is such that the head units 10 and 20 are moved in the conveyance width direction Y by moving the head units 10 and 20 in the direction opposite to the positional deviation. This is the amount of movement for positioning at an appropriate position. The rotation amount calculated by the second movement amount calculation unit 94 is a rotation amount for positioning each head unit 10, 20 at an appropriate position by rotating each head unit 10, 20. That is, the head units 10 and 20 are moved and rotated in the width direction based on the width direction movement amount and the rotation amount calculated by the second movement amount calculation unit 94, so that the same position as the first sheet P is obtained. The print image and the position correction mark are printed.

  The head units 10 and 20, the edge sensors S1 to S8 and the mark sensors S11 to S13, the transport information calculation unit 91, the first movement amount calculation unit 92, the head position information calculation unit 93, and the second movement amount calculation unit 94. The control unit 90 includes a recording position correction device that corrects the positions of the head units 10 and 20 according to the conveyance state of the paper P and prints at the same position as the printing on the first paper P. It has a function of correcting the positions of the head units 10 and 20 so as to be able to.

Next, the operation of the recording position correction apparatus during printing will be described.
FIG. 8 is a flowchart showing the operation of the recording position correction apparatus. The operation shown in the figure is started when the paper P to be printed is transported onto the transport surface 50. Although the operation in the head unit 10 will be described here, the same applies to the head unit 20.

  First, in step S10, the control unit 90 controls the edge sensors S1 to S8 and the mark sensors S11 to S13 disposed on the transport surface 50 to start the detection operation of each sensor.

  In step S <b> 20, the control unit 90 calculates the positional deviation amount and the skew amount of the paper P based on the detection results of the edge sensors S <b> 1 and S <b> 2 on the upstream side of the head unit 10 by the transport information calculation unit 91. Specifically, the positional deviation amount and the skew amount of the paper P are calculated based on the positions of the end portions in the width direction of the paper P detected by the edge sensors S1 and S2.

  In step S <b> 30, the control unit 90 moves in the transport width direction Y with respect to the head unit 10 based on the positional deviation amount and skew amount of the paper P calculated in step S <b> 20 by the first movement amount calculation unit 92. And the amount of rotation about the θ rotation axis 13 are calculated. Then, the control unit 90 moves the head unit 10 when there is a positional deviation or skew based on the calculated amount of movement and rotation of the head unit 10 in the width direction. As a result, the head unit 10 is subjected to width direction movement correction that is correction in the transport width direction Y and rotation correction about the θ rotation axis 13.

Here, when the calculated amount of movement in the width direction is 0 and the amount of rotation is 0, that is, when neither the positional deviation nor the skew is generated with respect to the paper P, the width relative to the head unit 10 is determined. Neither direction movement correction nor rotation correction is performed, and the state is left as it is.
On the other hand, when the movement amount in the width direction is other than 0 and the rotation amount is 0, that is, when only the positional deviation occurs with respect to the paper P and the skew does not occur, for example, as shown in FIG. Only the width direction movement correction is performed on the head unit 10.
On the other hand, when the movement amount in the width direction is 0 and the rotation amount is other than 0, that is, when only the skew is generated without causing the positional deviation with respect to the paper P, for example, as shown in FIG. Only rotation correction is performed on the head unit 10.
On the other hand, when the movement amount in the width direction is other than 0 and the rotation amount is other than 0, that is, when both the positional deviation and the skew are generated with respect to the sheet P, for example, FIGS. Like the combination, the rotation correction is performed on the head unit 10 together with the width direction movement correction.

  In step S40, the control unit 90 starts printing by ejecting ink droplets onto the paper P from the head unit 10 subjected to the width direction movement correction and the rotation correction in step S30.

  In step S <b> 50, the control unit 90 calculates the positional deviation amount and skew amount of the paper P based on the detection results of the edge sensors S <b> 3 and S <b> 4 arranged on the downstream side of the head unit 10 by the conveyance information calculation unit 91. calculate. Specifically, the positional deviation amount and the skew amount of the paper P are calculated based on the positions of the end portions in the width direction of the paper P detected by the edge sensors S3 and S4. Note that the detection results of the edge sensors S1 and S2 may be used in addition to the detection results of the edge sensors S3 and S4 when calculating the positional deviation amount and the skew amount.

  In step S <b> 60, the control unit 90 moves in the transport width direction Y with respect to the head unit 10 based on the positional deviation amount and skew amount of the paper P calculated in step S <b> 50 by the first movement amount calculation unit 92. And the amount of rotation about the θ rotation axis 13 are calculated. Then, the control unit 90 moves the head unit 10 when there is a positional deviation or skew based on the calculated amount of movement and rotation of the head unit 10 in the width direction. As a result, during printing on the paper P, the head unit 10 is subjected to width direction movement correction, which is correction in the transport width direction Y, and rotation correction about the θ rotation axis 13.

In step S70, the control unit 90 determines whether printing of one sheet of paper P has been completed.
When printing is completed, the process proceeds to the next step S80, and it is determined whether or not all printing is completed.
On the other hand, if the printing of one sheet of paper P is not completed in step S70, the printing of the paper P is continuing and the paper P is being conveyed. The positional deviation amount and the skew amount are calculated, and when there is a positional deviation or skew, the width direction movement correction and the rotation correction for the head unit 10 are repeated.

In step S80, the control unit 90 determines whether or not printing has been completed for all sheets P to be printed. When the printing of all the sheets P is finished, the printing process is finished.
On the other hand, if the paper P to be printed remains, the process proceeds to the next step S90.

  In step S90, the control unit 90 uses the head position information calculation unit 93 to detect the positional deviation amount and skew amount of the head unit 10 based on the positions of the position correction marks M1 and M2 detected by the mark sensors S11 to S13. Is calculated. Specifically, the position of the position correction marks M1 and M2 printed on the first sheet P is compared with the position of the position correction marks M1 and M2 detected this time to thereby determine the first sheet. A positional deviation amount and a skew amount of the head unit 10 with respect to the position of the head unit 10 at the time of printing, that is, an appropriate position are calculated.

In step S100, the control unit 90 uses the second movement amount calculation unit 94 to calculate the transport width direction Y with respect to the head unit 10 based on the positional deviation amount and skew amount of the head unit 10 calculated in step S90. And the amount of rotation about the θ rotation axis 13 are calculated. Then, the control unit 90 moves the head unit 10 when there is a positional deviation or skew based on the calculated amount of movement and rotation of the head unit 10 in the width direction.
Thereby, the width direction movement correction that is the correction in the transport width direction Y and the rotation correction about the θ rotation shaft 13 are performed on the head unit 10, and the head unit 10 is positioned at an appropriate position. .
When the correction of the head unit 10 is completed, the process returns to step S20, and the positional deviation amount and the skew amount of the next paper P are calculated in a state where the head unit 10 is positioned at an appropriate position.

  As described above, according to the ink jet printer 100 of the present embodiment, the following effects can be obtained.

In the inkjet printer 100 of the present embodiment, the second sheet is based on the position of the head unit when printing on the first sheet P based on the position of the position correction mark of the sheet P detected by the mark sensor. The positional deviation amount and skew amount of the head unit when printing on the subsequent paper P are calculated. Then, based on the calculated displacement amount and skew amount, the head unit is subjected to width direction movement correction and rotation correction, and the head unit is positioned at an appropriate position.
As a result, during printing of a plurality of sheets of paper P, if the position of the head unit is displaced from the initial position due to, for example, vibration or temperature change, the width direction movement correction and rotation correction are performed on the head unit. Thus, the position of the head unit can be adjusted to the position of the head unit when the first sheet P is printed. As a result, it is possible to cope with the problem of the positional deviation of the head unit during printing, and it is possible to perform printing at an accurate position while keeping the printing position on each paper P constant.

  In addition, after the head unit is adjusted for alignment, the position of the head unit is automatically adjusted to an appropriate position when the head unit is displaced during printing. Accordingly, there is no need to stop the printing operation or reprint again in order to readjust the position of the head unit, and it is possible to suppress a decrease in printing throughput and an increase in printing cost.

Further, during conveyance of the paper P, the width direction movement correction and the rotation correction are performed on the head unit based on the positional deviation amount and skew amount of the edge of the paper P detected by the edge sensor.
Thereby, for example, when the paper P is in a state of being displaced in the transport width direction Y, in a skewed state, in a state of being transported in an oblique direction, or the like, according to the transport state, the width direction The movement correction, the rotation correction, and the combination of the width direction movement correction and the rotation correction can be performed to make the relative position between the paper P and the head unit constant during printing. As a result, an image can be formed on an intended portion of the paper P, and an image with high resist accuracy and less visible unevenness can be formed.

(Second Embodiment)
Next, the inkjet printer 100 according to the second embodiment will be described.
The inkjet printer 100 according to the second embodiment has the same configuration as that of the inkjet printer 100 according to the first embodiment, but the operation of the recording position correction apparatus during printing is different.

  FIG. 9 is a flowchart showing the operation of the recording position correction apparatus in the second embodiment. The flowchart shown in the figure and the flowchart in the first embodiment shown in FIG. 8 are different in the conditions of the operation for correcting the head unit. In the flowchart in the first embodiment shown in FIG. 8, the operation is shifted to the operation for correcting the head unit unconditionally. In the flowchart in the second embodiment shown in FIG. 9, is the operation shifted to the operation for correcting the head unit? A determination process of whether or not is added. In this determination process, a preset misalignment allowable value is used.

As shown in the flowchart in the second embodiment shown in FIG. 9, before performing the operation of correcting the head unit in step S30, in step S25, the control unit 90 calculates the positional deviation amount of the paper P calculated in step S20. It is determined whether the skew amount exceeds an allowable value. Only when either the positional deviation amount or the skew amount exceeds the allowable value, the process proceeds to step S30, and the control unit 90 performs the width direction movement correction and the rotation correction for the head unit 10.
On the other hand, if both the positional deviation amount and the skew feeding amount are within the allowable values, the process proceeds to step S40 without correcting the head unit 10.

Further, before performing the operation of correcting the head unit in step S60, in step S55, the control unit 90 determines whether or not the positional deviation amount and skew amount of the paper P calculated in step S50 exceed allowable values. judge. Only when one of the positional deviation amount and the skew feeding amount exceeds the allowable value, the process proceeds to step S60, and the control unit 90 performs the width direction movement correction and the rotation correction for the head unit 10.
On the other hand, if both the positional deviation amount and the skew amount are within the allowable values, the process proceeds to step S70 without correcting the head unit 10.

In addition, before performing the operation of correcting the head unit in step S100, in step S95, the control unit 90 determines whether the positional deviation amount and the skew amount of the head unit 10 calculated in step S90 exceed allowable values. Determine. Only when either the positional deviation amount or the skew amount exceeds the allowable value, the process proceeds to step S100, and the control unit 90 performs the width direction movement correction and the rotation correction for the head unit 10.
On the other hand, when both the positional deviation amount and the skew feeding amount are within the allowable values, the head unit 10 is not corrected and the process returns to step S20.

Here, the allowable values used in the above-described steps S25, S55, and S95 are specified values for determining whether or not the misalignment and skew state require a correction of the head unit. . This specified value may be set freely by the user depending on the print contents such as text printing and photo printing, the required image quality, and the like.
In this embodiment, the determination process for determining whether or not to shift to the correction operation is added to all the operations for correcting the head unit. For example, the determination process is performed only for the correction operation of the head unit in step S100. A determination process may be selectively added, such as adding.

In the ink jet printer 100 according to the present embodiment, it is determined whether the positional deviation amount and the skew amount of the paper P and the head unit exceed the allowable values, and the width of the head unit with respect to the head unit only when the allowable values are exceeded. Perform direction movement correction and rotation correction.
Accordingly, when the positional deviation and skew of the paper P and the head unit are so small that they do not affect the user, it is possible to eliminate the correction for the head unit, and the time and power required for the correction. Consumption can be saved.

(Modification)
In the above-described embodiment, as shown in FIG. 1 and the like, one common transport unit 1 is provided for the two head units of the head units 10 and 20. However, the present invention is not limited to this. For example, as shown in a side sectional view schematically showing the outline of the ink jet printer 300 in FIG. 10, a tandem type in which a transport unit 1 is provided as an independent mechanism for each head unit 10, 20. It may be configured as follows.

  In addition, the plurality of ejection heads 11 are divided and arranged by the two head units 10 and 20, but the invention is not limited to this. The inkjet printer includes only one head unit, and all the ejection units are disposed in the head unit. A configuration in which the heads are arranged may be employed.

1 is a side sectional view schematically showing an outline of an ink jet printer according to a first embodiment. FIG. 2 is a plan view schematically showing the outline of the ink jet printer according to the first embodiment. It is explanatory drawing of the arrangement | sequence of each discharge head, and the figure which looked at the head unit from the downward direction. Explanatory drawing of the mechanism and operation | movement which concern on reciprocation and rotation of a head unit. FIG. 3 is a plan view showing an example of a position correction mark printed on a sheet by an ink jet printer. FIG. 3 is an explanatory diagram for calculating a positional deviation amount of a head unit from a sheet position correction mark. FIG. 4 is an explanatory diagram for calculating a skew amount of a head unit from a sheet position correction mark. 6 is a flowchart illustrating the operation of the recording position correction apparatus according to the first embodiment. 9 is a flowchart showing the operation of the recording position correction apparatus in the second embodiment. 1 is a side sectional view schematically showing an outline of a tandem type ink jet printer.

  DESCRIPTION OF SYMBOLS 1 ... Conveyance part, 2 ... Printing part, 10, 20 ... Head unit, 11 ... Discharge head, 12 ... Head panel, 13 ... θ rotation axis, 14 ... Y axis motor, 15 ... θ axis motor, 31 ... Gate roller, 32 ... driven roller, 33 ... tension roller, 34 ... drive roller, 35 ... endless belt, 36 ... transport drive motor, 37 ... vent hole, 50 ... transport surface, 90 ... control unit, 91 ... transport information calculation unit, 92 ... First movement amount calculation unit, 93 ... head position information calculation unit, 94 ... second movement amount calculation unit, 100 ... inkjet printer, 300 ... inkjet printer according to modification, P ... paper, S1 to S8 ... edge sensor, S11 ~ S13 ... Mark sensor.

Claims (11)

A head unit for ejecting and recording a liquid onto a recording medium conveyed on the conveying surface;
A mark detection unit for detecting a position correction mark recorded on the recording medium;
The head when recording is performed on the recording medium after the one recording medium when the position of the head unit when recording on the one recording medium is an appropriate position to be positioned by the head unit. About the position of the unit, a head position information calculation unit that calculates head position information indicating a positional deviation state with respect to the appropriate position;
A recording position correction apparatus comprising: a control unit that moves the head unit in a direction parallel to the transport surface based on the head position information, and positions the head unit at the appropriate position.   The head position information includes a displacement amount from the appropriate position in a direction perpendicular to the conveyance direction of the recording medium, and the control unit moves the head unit based on the displacement amount. The recording position correcting apparatus according to claim 1.   The head position information includes a skew amount with respect to the head unit located at the appropriate position, and the control unit moves the head unit in a direction perpendicular to the transport surface based on the skew amount. The recording position correcting apparatus according to claim 1, wherein the recording position correcting apparatus is rotated about an axis.   The control unit moves the head unit in a direction parallel to the transport surface only when the positional deviation state indicated by the head positional information is larger than a predetermined positional deviation allowable value. Item 4. The recording position correction apparatus according to any one of Items 1 to 3.   The recording position correction apparatus according to claim 1, wherein the position correction mark is recorded on a cutting portion of the recording medium. A plurality of the position correction marks are recorded in the width direction of the recording medium,
The recording position correction apparatus according to claim 1, wherein a plurality of the mark detection units are arranged in the width direction of the recording medium.   The recording position correction apparatus according to claim 1, wherein the mark detection unit moves according to a size of the recording medium. A recording medium detection unit for detecting a position of the conveyed recording medium;
A conveyance information calculation unit that calculates conveyance information indicating a conveyance state of the recording medium based on the detected position of the recording medium;
8. The control unit according to claim 1, wherein the control unit moves the head unit to a position corresponding to the conveyance information in a direction parallel to the conveyance surface based on the conveyance information. The recording position correction apparatus described.   The transport information includes a displacement amount from a predetermined reference position in the width direction of the recording medium, and the control unit moves the head unit based on the displacement amount. The recording position correction apparatus according to 8.   The transport information includes a skew amount of the recording medium, and the control unit rotates the head unit about an axis in a direction perpendicular to the transport surface based on the skew amount. The recording position correction apparatus according to claim 8 or 9.   A recording apparatus comprising the recording position correcting apparatus according to claim 1 and performing recording on a recording medium.

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