JP2011136526A - Recording position correction apparatus, control program thereof, control method thereof and recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve such a problem that the relative position of a recording medium and a head unit cannot be kept constant when the recording medium is conveyed while being misaligned from an original position, and thereby an image cannot be formed at an intended part of the recording medium. <P>SOLUTION: An ink jet printer 100 includes first and second head units 10 and 20 which discharge ink droplets toward paper P conveyed on the conveying surface 50, edge sensors S1 and S2 which detect the position p1 of the paper P near the first head unit 10, and the position p2 of the paper P near the second head unit 20, a correction amount information generation unit 91 which generates correction amount information for correcting the relative misalignment of the discharge position of the second head unit 20 to the discharge position of an ink droplet from the first head unit 10 on the paper P based on the p1 and p2, and a position correction unit 92 which corrects the discharge position by controlling the Y axis motor 14 of the second head unit 20 based on the generated correction amount information. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a recording position correction apparatus, a recording position correction apparatus control program, a recording position correction apparatus control method, and a recording apparatus.

2. Description of the Related Art Conventionally, in a recording apparatus such as an ink jet printer, various techniques for ejecting liquid droplets from a head unit to an accurate position with respect to a transported recording medium have been proposed.
For example, in the ink jet printer described in Patent Document 1 below, in order to land droplets at an accurate position even in a print medium region where the transport speed is not constant, the transport speed of the print medium is detected and the discharge timing is set. I am trying to correct it.
In addition, in the inkjet printer described in Patent Document 2 below, the alignment adjustment of the line head is automatically performed with high accuracy in order to prevent printing defects such as oblique lines due to the alignment failure of the line head. Yes.

JP-A-8-230194 JP 2008-12712 A

However, the ink jet printer described in Patent Document 1 cannot cope with a change in the behavior in the width direction of the print medium during printing. As described above, when the relative position between the print medium and the head unit is not constant, an image cannot be formed on an intended portion of the print medium. In addition, in the case of the above-mentioned patent document 2, it is a proposal regarding the alignment method of the line head of the ink jet printer, and as in the case of the above-described patent document 1, the relative position between the print medium and the head unit during printing is changed. I cannot respond to it.
Accordingly, the present invention has been made paying attention to such an unsolved problem of the conventional technology, and a recording position correction apparatus and a recording position capable of solving at least a part of the above-described problems It is an object of the present invention to provide a control program for a correction apparatus, a control method for a recording position correction apparatus, and a recording apparatus.

[Mode 1] In order to achieve the above object, a recording position correction apparatus according to mode 1 includes a transport unit that transports a recording medium, and a first head unit that ejects ink droplets onto the recording medium transported by the transport unit. And a second head unit that is disposed in parallel with the transport direction in the same posture as the first head unit and ejects ink droplets onto a recording medium transported by the transport means, A recording position correction device for controlling a recording position of the image of a recording device that controls one head unit and the second head unit to record an image on the recording medium;
Head unit moving means for moving the second head unit in a predetermined direction;
First position information detecting means for detecting position information of a recording medium conveyed by the conveying means in the vicinity of the ink droplet ejection position of the first head unit;
Second position information detecting means for detecting position information of a recording medium conveyed by the conveying means in the vicinity of the ink droplet ejection position of the second head unit;
The second head based on first position information that is position information detected by the first position information detection means and second position information that is position information detected by the second position information detection means. Correction amount information generating means for generating correction amount information that is a correction amount of the ejection position of the ink droplet of the unit;
Position correction means for controlling the head unit moving means based on the correction amount information generated by the correction amount information generating means to correct the ejection position of the second head unit;
The correction amount information generation unit corresponds to the displacement amount of the discharge position relative to the discharge position of the first head unit relative to the discharge position of the first head unit in the predetermined direction as the correction amount information. Information on the amount of correction to be performed,
The position correcting unit controls the head unit moving unit based on the correction amount information, so that the relative position of the second head unit in the predetermined direction with respect to the ejection position of the first head unit with respect to the recording medium. Correct misalignment of the discharge position.

With such a configuration, the position information (first position information) in the vicinity of the ink droplet ejection position of the first head unit of the recording medium conveyed by the conveying means is detected by the first position information detecting means. It is possible to detect. Further, it is possible to detect position information (second position information) in the vicinity of the ejection position of the second head unit of the recording medium conveyed by the conveying means by the second position information detecting means. Further, the correction amount information generating means corrects the relative displacement amount of the second head unit relative to the ejection position of the first head unit based on the first position information and the second position information. It is possible to generate correction amount information that is amount information. Then, the position correction unit controls the head unit moving unit based on the correction amount information to correct the displacement of the discharge position of the second head unit relative to the discharge position of the first head unit with respect to the recording medium. Is possible.
Accordingly, even if the position of the recording medium fluctuates in a predetermined direction while being conveyed by the conveying means, the second head unit is controlled to move, and the second head relative to the ink droplet ejection position with respect to the recording medium of the first head unit. The displacement of the relative discharge position of the unit can be corrected. Thereby, the effect that the recording accuracy of an image can be improved is obtained.

For example, when the first head unit records a part of the image line constituting the image and the second head unit records the remaining part of the image line constituting the image, the relative positions of the two dots are changed. Since it can be made constant, it is possible to reduce the occurrence of density unevenness and color unevenness due to dot displacement.
Here, the positional fluctuation of the recording medium being conveyed by the conveying means is abrupt due to periodic position fluctuations caused by vibration inherent in the conveying means or vibrations caused by external force applied. There are position fluctuations that occur in

[Mode 2] Furthermore, the recording position correction apparatus according to mode 2 is the recording position correction apparatus according to mode 1, wherein the second head unit is disposed downstream of the first head unit in the transport direction. And
The first position information detecting means detects position information of a recording medium conveyed by the conveying means on the upstream side of the first head unit;
The second position information detecting means detects position information of a recording medium conveyed by the conveying means on the downstream side of the first head unit and on the upstream side of the second head unit;
The correction amount information generating unit detects the predetermined amount of the second head unit relative to the discharge position of the first head unit with respect to the recording medium as the correction amount information every time the second position information is detected. The correction amount information corresponding to the displacement amount of the discharge position relative to the direction is sequentially generated,
The position correction unit controls the head unit moving unit each time the correction amount information is generated, so that the predetermined value of the second head unit with respect to the ejection position of the first head unit with respect to the recording medium. The displacement of the relative discharge position in the direction is sequentially corrected.

With such a configuration, the position information (first position information) on the upstream side of the first head unit of the recording medium conveyed by the conveying means can be detected by the first position information detecting means. Is possible. Further, the position information (second position information) on the downstream side of the first head unit and the upstream side of the second head unit of the recording medium conveyed by the conveying means by the second position information detecting means. Can be detected. In addition, the correction amount information generation means sets the displacement amount of the discharge position of the second head unit relative to the discharge position of the first head unit with respect to the recording medium based on the first position information and the second position information. It is possible to generate correction amount information that is information of the corresponding correction amount. Then, the position correction unit controls the head unit moving unit based on the correction amount information to correct the displacement of the discharge position of the second head unit relative to the discharge position of the first head unit with respect to the recording medium. Is possible.
Therefore, even if the position of the recording medium fluctuates in a predetermined direction while being conveyed by the conveying means, the movement of the second head unit is controlled in real time to the ink droplet ejection position with respect to the recording medium of the first head unit. The relative displacement of the second head unit can be corrected. Thereby, the effect that the recording accuracy of an image can be improved is obtained.

[Mode 3] Furthermore, the recording position correction apparatus according to mode 3 is the recording position correction apparatus according to mode 1, wherein the first position information detection means uses the first head unit as the first position information. Detecting position information that periodically changes in the predetermined direction at the same position as the first head unit or upstream side,
The second position information detecting unit is configured to detect, as the second position information, a position downstream of the first head unit and upstream of the second head unit or the same position as the second head unit. Detecting position information periodically changing in the predetermined direction at
The correction amount information generation unit is configured to detect the first change with respect to a position change of one period of the recording medium based on the first position information and the second position information that change periodically as the correction amount information. Generating correction amount information corresponding to a displacement amount of the discharge position of the second head unit relative to the discharge position of the head unit with respect to the recording medium;
The position correcting means controls the head unit moving means based on correction amount information for the position fluctuation for the one period, and the second head unit relative to the ejection position of the first head unit with respect to the recording medium. The relative displacement of the discharge position in the predetermined direction is corrected.

With such a configuration, since the movement operation of the second head unit can be controlled based on the correction amount information for the position fluctuation for one cycle generated in advance, correction is performed in real time during image recording. It is not necessary to perform processing for generating quantity information. As a result, it is possible to reduce or prevent the occurrence of a situation where the position correction of the second head unit is not in time for high-speed image recording.
Here, for example, the periodic position fluctuation of the recording medium caused by vibrations in a predetermined direction of the conveying means hardly changes unless an external force is applied. Therefore, the same correction amount information can be repeatedly used in image recording on a plurality of recording media by measuring the periodic position variation during image recording and the like to generate correction amount information.

[Mode 4] Furthermore, the recording position correction apparatus according to mode 4 is the recording position correction apparatus according to any one of modes 1 to 3, wherein the predetermined direction is parallel to the transport surface and orthogonal to the transport direction. Including direction.
With such a configuration, the displacement of the relative ejection position of the ink droplet due to the position variation of the recording medium conveyed by the conveying means in the direction parallel to the recording surface and perpendicular to the conveying direction is corrected. Can do.
That is, it is possible to correct the relative ejection position deviation of the second head unit by following the periodic position fluctuation (meandering movement) in the direction orthogonal to the conveyance direction of the recording medium conveyed by the conveyance means. Therefore, it is possible to improve the recording position accuracy of the recording apparatus.

[Mode 5] On the other hand, in order to achieve the above object, a control program for a recording position correction apparatus according to mode 5 ejects ink droplets onto a transport unit that transports a recording medium and to the recording medium transported by the transport unit. A first head unit, and a second head unit that is arranged in parallel with the transport direction in the same posture as the first head unit and that ejects ink droplets onto a recording medium transported by the transport unit; A control program for a recording position correction device for controlling the first head unit and the second head unit to correct the recording position of the image of a recording device for recording an image on the recording medium,
The recording position correction apparatus includes a head unit moving unit that moves the second head unit in a predetermined direction, and a recording in which the vicinity of the ink droplet ejection position of the first head unit is conveyed by the conveying unit. First position information detecting means for detecting the position information of the medium, and second position information for detecting the position information of the recording medium conveyed by the conveying means in the vicinity of the ink droplet ejection position of the second head unit. And position information detecting means,
The second head based on first position information that is position information detected by the first position information detection means and second position information that is position information detected by the second position information detection means. A correction amount information generating step for generating correction amount information that is a correction amount of the ejection position of the ink droplet of the unit;
For causing a computer to execute processing including a position correction step of controlling the head unit moving unit based on the correction amount information generated in the correction amount information generation step to correct the ejection position of the second head unit. Including programs,
In the correction amount information generating step, as the correction amount information, a displacement amount of the discharge position relative to the discharge position of the first head unit with respect to the recording medium in the predetermined direction of the second head unit. Generate corresponding correction amount information,
In the position correction step, the head unit moving unit is controlled based on the correction amount information, and the second head unit in the predetermined direction with respect to the ejection position of the first head unit with respect to the recording medium. The relative displacement of the discharge position is corrected.
With such a configuration, when the program is read by the computer and the computer executes processing according to the read program, the same operation and effect as those of the recording position correction apparatus according to mode 1 can be obtained.

[Mode 6] In order to achieve the above object, a control method for a recording position correction apparatus according to mode 6 includes a transport unit that transports a recording medium, and ejects ink droplets onto the recording medium transported by the transport unit. A first head unit, and a second head unit that is arranged in parallel with the transport direction in the same posture as the first head unit and that ejects ink droplets onto a recording medium transported by the transport unit; A control method for a recording position correction device for controlling the first head unit and the second head unit to correct the recording position of the image of a recording device for recording an image on the recording medium,
The recording position correction apparatus includes a head unit moving unit that moves the second head unit in a predetermined direction, and a recording in which the vicinity of the ink droplet ejection position of the first head unit is conveyed by the conveying unit. First position information detecting means for detecting the position information of the medium, and second position information for detecting the position information of the recording medium conveyed by the conveying means in the vicinity of the ink droplet ejection position of the second head unit. And position information detecting means,
The second head based on first position information that is position information detected by the first position information detection means and second position information that is position information detected by the second position information detection means. A correction amount information generating step for generating correction amount information that is a correction amount of the ejection position of the ink droplet of the unit;
A position correction step of controlling the head unit moving means based on the correction amount information generated in the correction amount information generation step to correct the ejection position of the second head unit,
In the correction amount information generating step, as the correction amount information, a displacement amount of the discharge position relative to the discharge position of the first head unit with respect to the recording medium in the predetermined direction of the second head unit. Generate corresponding correction amount information,
In the position correction step, the head unit moving unit is controlled based on the correction amount information, and the second head unit in the predetermined direction with respect to the ejection position of the first head unit with respect to the recording medium. The relative displacement of the discharge position is corrected.
Thereby, the same operation and effect as the recording position correcting apparatus described in the first embodiment can be obtained.

[Mode 7] In order to achieve the above object, a recording apparatus according to mode 7 includes: a transport unit that transports a recording medium;
A first head unit that ejects ink droplets onto a recording medium conveyed by the conveying means;
A second head unit that is disposed in parallel with the transport direction in the same posture as the first head unit and ejects ink droplets onto a recording medium transported by the transport means;
Image recording means for controlling the first head unit and the second head unit to record an image on the recording medium;
The recording position correction apparatus described in any one of Embodiments 1 to 4.
Thereby, the same operation and effect as those of the recording position correction apparatus described in any one of Forms 1 to 4 can be obtained.

1 is a side sectional view schematically showing a schematic configuration of an inkjet printer 100 according to the present embodiment. 1 is a plan view schematically showing a schematic configuration of an inkjet printer 100. FIG. It is explanatory drawing of the arrangement | sequence of each discharge head 11 and 21, and is the figure which looked at the 1st, 2nd head units 10 and 20 from the downward direction. FIG. 6 is an explanatory diagram of a mechanism and an operation related to the movement of the second head unit 20. (A) is a figure which shows the example of an ideal discharge position, (b) And (c) is a figure which shows an example of the discharge position in case the relative position shift has arisen. 4 is a flowchart illustrating an example of an operation process of the recording position correction apparatus and a drive control process of the first head unit 10. 4 is a flowchart illustrating an example of an operation process of a recording position correction apparatus and a drive control process of a second head unit 20. (A), (b) is a figure which shows an example of the detection signal of position p1, p2 of the paper P edge part in edge sensor S1, S2, (c) is a figure of the difference of the position detection signal of S1, S2. It is a figure which shows a signal (p2-p1). (A) And (b) is a figure explaining the operation | movement which correct | amends the relative position shift of the discharge position of the 2nd head unit 20 with respect to the discharge position of the 1st head unit 10 in the paper P. FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 9 are diagrams showing an embodiment of a recording position correcting apparatus, a recording position correcting apparatus control program, a recording position correcting apparatus control method, and a recording apparatus according to the present invention.
Hereinafter, an ink jet printer that records (prints) an image on a recording medium such as paper by ejecting ink droplets will be described as an example of a recording apparatus that includes a recording position correction apparatus and performs recording on a recording medium. 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.

First, a schematic configuration of the ink jet printer according to the present embodiment will be described with reference to the drawings.
Here, FIG. 1 is a side sectional view schematically showing a schematic configuration of the ink jet printer 100 according to the present embodiment. FIG. 2 is a plan view schematically showing a schematic configuration of the ink jet printer 100.
As shown in FIGS. 1 and 2, inside the inkjet printer 100, a printing unit 1 that holds and conveys paper P to be printed, and printing on the paper P that is held and conveyed by the conveyance unit 1. A printing unit 2 to be executed 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 wound around these three rollers 32, 33, 34 in a loop shape, and the like.
The drive roller 34 is a roller that is rotationally driven by an actuator such as a motor and applies a transport force in the transport direction X to the endless belt 35.
In the present embodiment, as shown in FIG. 2, a conveyance drive motor 36 for transmitting power to the drive roller 34 is directly connected to one end of the drive roller 34 in the conveyance width direction Y. The drive roller 34 is rotationally driven.

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 first head unit 10 disposed on the upstream side in the transport direction X, a second head unit 20 disposed on the downstream side of the first head unit 10, and the like.
As shown in FIG. 2, the first head unit 10 includes a rectangular parallelepiped head panel 12 having a rectangular shape in plan view whose length in the transport width direction Y is longer than the transport surface 50, and four plan view rectangles that eject ink droplets. And a rectangular parallelepiped discharge head 11.
The four rectangular parallelepiped discharge heads 11 are arranged so that the sides extending in the longitudinal direction are parallel to the sides extending in the longitudinal direction of the head panel 12, and the four along the transport width direction Y are straight in order at a certain interval. Arranged and incorporated in the head panel 12.

Further, as shown in FIG. 2, the second head unit 20 includes a rectangular parallelepiped head panel 22 having a length in the transport width direction Y longer than the transport surface 50 and three planes for ejecting ink droplets. And a rectangular parallelepiped-shaped discharge head 21.
The three rectangular parallelepiped discharge heads 21 are arranged so that the sides extending in the longitudinal direction are parallel to the sides extending in the longitudinal direction of the head panel 22, and the three are straight along the transport width direction Y in order with a certain interval. Arranged and incorporated in the head panel 12.

Further, the four ejection heads 11 of the head panel 12 and the three ejection heads 21 of the head panel 22 are upstream and downstream in the transport direction X so that the ejection heads are arranged in a staggered manner in plan view. Are arranged so that the positions in the transport width direction Y are staggered.
Further, the second head unit 20 can be reciprocated in the transport width direction Y by the Y-axis motor 14 or the like provided therein. Details of the movement of the second head unit 20 will be described later.

Next, the arrangement of the ejection heads 11 and 21 will be described in detail with reference to FIG.
Here, FIG. 3 is an explanatory diagram of the arrangement of the ejection heads 11 and 21, and is a view of the first and second head units 10 and 20 as viewed from below.
In each of the ejection heads 11 and 21, a number of nozzles that eject ink droplets are formed with ejection holes on the lower surface facing the transport surface 50.
Specifically, on the lower surface of each of the ejection heads 11 and 21 facing the transport surface 50, as shown in FIG. 3, a nozzle hole array made up of a plurality of nozzles arranged along the transport width direction Y is formed. , Four rows are formed apart in the transport direction X. Ink droplets of different colors can be ejected from the nozzle rows corresponding to these four nozzle hole rows, and in this embodiment, black (K), cyan (C) in order from the upstream side in the transport direction X. ), Magenta (M) and yellow (Y) ink droplets are ejected.

  Further, each of the ejection heads 11 and 21 has one end or the other end in the conveyance width direction Y of each of the two ejection heads 11 corresponding to each ejection head 21 at the nozzle positions at both ends in the conveyance width direction Y of each ejection head 21. It is arrange | positioned so that it may become the same position as the nozzle position of a part. 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, by only 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 first and second head units 10 and 20 can be printed. it can.

  The method of ejecting ink droplets from the nozzle 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.

Next, a configuration in which the second head unit 20 is reciprocated in the transport width direction Y that is parallel to the transport surface 50 will be described in detail with reference to FIG.
Here, FIG. 4 is an explanatory view of the mechanism and operation relating to the movement of the second head unit 20.
As shown in FIG. 4, the second head unit 20 includes a Y-axis motor 14 that transmits power for reciprocating the head panel 22 in the transport width direction Y, and an unillustrated extending along the transport width direction Y. A slide rail is attached. Thereby, the Y-axis motor 14 can be driven, and the 2nd head unit 20 can be reciprocated in the conveyance width direction Y according to a slide rail. In the present embodiment, as the Y-axis motor 14 attached to the second head unit 20, for example, a linear ultrasonic motor capable of controlling minute displacement is used.

FIG. 4 shows an example in which the second head unit 20 has moved by Ya in the conveyance width direction Y from the reference position. This is a result of driving the Y-axis motor 14 based on the control of the control unit 90 and moving the head panel 22 in the transport width direction Y by Ya according to the slide rail.
The first head unit 10 is not provided with a mechanism required for movement, such as the Y-axis motor 14 and the slide rail, and is configured to be fixedly arranged at a position determined at the time of design. That is, the first head unit 10 always ejects ink droplets at a fixed position.
Referring back to FIGS. 1 and 2, the edge sensor S <b> 1 is disposed in the vicinity of the first head unit 10 and on the upstream side in the transport direction X from the first head unit 10. Further, in the vicinity of the second head unit 20, an edge sensor S <b> 2 is disposed downstream of the first head unit 10 in the transport direction X and upstream of the second head unit 20 in the transport direction X. .

The edge sensors S1 and S2 are sensors that detect the position of the end in the width direction of the paper P, and are, for example, reflection type 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 and S2 detect the position of the edge in the width direction of the paper P on the conveyance surface 50 by irradiating light from the light emitting elements in the direction of the conveyance surface 50 and receiving reflected light by a plurality of light receiving elements. be able to. In the present embodiment, for example, a CCD image sensor or a CMOS image sensor is used as the edge sensors S1 and S2. Note that the edge sensors S1 and S2 are fixedly disposed in a stationary portion in the inkjet printer 100 that does not change in position due to vibration of the conveyance surface 50 or the like.
The control unit 90 includes a CPU, a ROM, a RAM, and the like (not shown), and controls each unit and each mechanism in the inkjet printer 100 as a whole.

Further, as shown in FIG. 2, the control unit 90 includes a correction amount information generation unit 91 and a position correction unit 92.
The correction amount information generation unit 91, in response to a print instruction, the first position information that is the position information of the paper P edge detected by the edge sensor S1, and the position of the paper P edge detected by the edge sensor S2. The second position information which is information is acquired. Then, based on the first position information and the second position information, the ink droplet ejection position of the second head unit 20 for correcting the position variation in the transport width direction Y of the paper P transported on the transport surface 50 is corrected. Generate correction amount information.
Specifically, the correction amount information generation unit 91 firstly, based on the first position information p1 of the end portion in the width direction detected when the paper P transported on the transport surface 50 passes through the edge sensor S1. A first positional deviation amount d1 (p1-rp), which is a deviation amount with respect to the reference position rp at the width direction end of the paper P, is calculated.

Next, the correction amount information generation unit 91 determines the sheet P based on the second position information p2 at the end in the width direction detected when the sheet P conveyed on the conveyance surface 50 passes the edge sensor S2. A second positional shift amount d2 (p2-rp) that is a shift amount of the end portion in the width direction with respect to the reference position rp is calculated.
In addition, when viewed in plan view of the transport surface 50, the upward shift in the transport width direction Y is defined as a positive shift and the downward shift in the negative direction with respect to the reference position rp at the end in the width direction of the paper P. Let it be a shift.

Then, by calculating the difference between the first positional deviation amount d1 and the second positional deviation amount d2 according to the following equation (1), the second head relative to the ink droplet ejection position on the paper P of the first head unit 10 is calculated. A relative positional deviation amount D that is a relative positional deviation amount of the ejection position of the head unit 20 is calculated.

D = d2-d1 (1)

Then, based on the relative displacement amount D, the relative displacement in the transport width direction Y of the ejection position of the second head unit 20 with respect to the ejection position of the ink droplets on the paper P of the first head unit 10 is obtained as correction amount information. A control amount of the Y-axis motor 14 for moving the second head unit 20 in the canceling direction is calculated.
The position correction unit 92 controls the Y-axis motor 14 based on the correction amount information generated by the correction amount information generation unit 91 to correct the ink droplet ejection position.

Specifically, the position correction unit 92 is configured to cancel the relative positional deviation of the discharge position of the second head unit 20 with respect to the discharge position of the first head unit 10 with respect to the paper P based on the correction amount information. A motor control signal for moving 20 in the transport width direction Y is generated and supplied to the Y-axis motor 14.
The control unit 90 including the second head unit 20, the edge sensors S 1 and S 2, the correction amount information generation unit 91, and the position correction unit 92 constitutes a recording position correction device, and responds to position variations in the conveyance width direction Y. The second head unit 20 has a function of correcting the ejection position of the ink droplets onto the paper P. Note that the number and arrangement positions of the edge sensors to be arranged are not limited to the above.

Next, based on FIG. 5, changes in the ink droplet ejection positions of the first and second head units 10 and 20 due to the meandering of the paper P will be described. In FIG. 5, black dots are dots formed by ejecting ink droplets from the first head unit 10, and gray dots are dots formed by ejecting ink droplets from the second head unit 20.
Here, FIG. 5A is a diagram illustrating an example of an ideal ejection position, and FIGS. 5B and 5C are diagrams illustrating an example of the ejection position when a relative positional deviation occurs. It is.
As shown in FIG. 5A, when there is no relative shift in the discharge position of the second head unit 20 with respect to the discharge position of the first head unit 10 with respect to the paper P, the dot rows formed by the both are Each dot is at a constant interval.

On the other hand, in the example of FIG. 5B, the dot row formed by the second head unit 20 is moved downward with respect to the dots at the lower end of the dot row formed by the first head unit 10. The intervals are wider than shown in FIG. This is because the ejection position of the second head unit 20 is relatively shifted downward in the conveyance width direction Y with respect to the ejection position of the first head unit 10 with respect to the paper P in plan view. It occurs because of being.
In the example of FIG. 5C, the dot at the upper end of the dot row formed by the second head unit 20 overlaps the dot at the lower end of the dot row formed by the first head unit 10. Yes. This is because the ejection position of the second head unit 20 is relatively shifted upward in the conveyance width direction Y with respect to the ejection position of the first head unit 10 with respect to the paper P in plan view of the conveyance surface 50. It occurs because of being.

  5B and 5C may cause density unevenness and color unevenness in a recorded image (printed image) when viewed from a macro viewpoint. In the present embodiment, by correcting the relative ejection position deviation of the ink droplets of the second head unit 20 with respect to the first head unit 10 due to the positional deviation of the paper P in the transport width direction Y, the density unevenness of the print image is reduced. The purpose is to reduce color unevenness.

Next, the flow of the operation process of the recording position correction apparatus and the drive control process of the first head unit 10 will be described with reference to FIG.
Here, FIG. 6 is a flowchart illustrating an example of an operation process of the recording position correction apparatus and a drive control process of the first head unit 10.
When the paper P is fed and conveyed in response to the print instruction and the position detection operation of the edge sensors S1 and S2 is started, the process proceeds to step S100 as shown in FIG.

  In step S100, the correction amount information generation unit 91 determines whether or not the upstream edge sensor S1 has detected the edge of the paper P. If it is determined that it has been detected (Yes), the process proceeds to step S102. If not (No), the determination process is repeated until detection. If the paper position is not detected after the specified time, a paper jam or the like is dealt with. For example, the control unit 90 displays a message indicating that a jam or the like has occurred on the paper P on an operation screen (not shown) and accepts a user operation.

When the process proceeds to step S102, the correction amount information generation unit 91 starts a first timer (not shown) and proceeds to step S104.
In step S104, the correction amount information generation unit 91 calculates the first positional deviation amount d1 based on the first position information p1 detected by the edge sensor S1 and the preset reference position rp of the paper P. Then, the process proceeds to step S106.

In step S106, the correction amount information generation unit 91 stores the first positional deviation amount d1 calculated in step S104 in a memory such as a RAM in association with the count value of the first timer, and the process proceeds to step S108. .
In step S108, the controller 90 drives each ejection nozzle 11 of the first head unit 10 based on the count value of the timer, and ejects ink onto the recording surface of the paper P at a preset timing. Transition.

In step S110, the control unit 90 determines whether or not the discharge time has elapsed. If it is determined that the discharge time has elapsed (Yes), the process proceeds to step S112. If not (No), the process proceeds to step S104. To do. Instead of determining whether or not the ejection time has elapsed, a sensor that detects the end of the sheet P1 is provided to determine whether or not printing for the sheet P1 has been completed. good.
When the process proceeds to step S112, the control unit 90 determines whether or not printing for the designated number of sheets designated by the print instruction has been completed. If it is determined that the printing has been completed (Yes), the series of processes is terminated. If not (No), the process proceeds to step S100.

Next, the flow of the operation process of the recording position correction apparatus and the drive control process of the second head unit 20 will be described with reference to FIG.
Here, FIG. 7 is a flowchart illustrating an example of an operation process of the recording position correction apparatus and a drive control process of the second head unit 20.
When the paper P is fed and conveyed in response to the print instruction and the position detection operation of the edge sensors S1 and S2 is started, the process proceeds to step S200 as shown in FIG.

  In step S200, the correction amount information generation unit 91 determines whether or not the downstream edge sensor S2 has detected the edge of the paper P. If it is determined that it has been detected (Yes), the process proceeds to step S202. If not (No), the determination process is repeated until detection. If the paper position is not detected after the specified time has elapsed after the paper position is detected by the edge sensor S1, the detection area of the edge sensor S2 is set due to the occurrence of an abnormality such as the skew amount of the paper P being too large. There may be a deviation. Therefore, for example, the control unit 90 displays a message indicating that an abnormality has occurred in the paper P on an operation screen (not shown), and performs a response such as accepting a user operation.

When the process proceeds to step S202, the correction amount information generation unit 91 starts a second timer (not shown), and the process proceeds to step S204.
In step S204, the correction amount information generation unit 91 calculates the second positional deviation amount d2 based on the second position information p2 detected by the edge sensor S2 and the preset reference position rp of the paper P. Then, the process proceeds to step S206. At this time, the calculated second positional deviation amount d2 is temporarily stored in a memory such as a RAM in association with the count value of the second timer.

  In step S206, the correction amount information generation unit 91 uses the second positional deviation amount d2 calculated in step S204 and the first positional deviation amount d1 having the same count value as the count value corresponding to d2 stored in the memory. Is read from memory. Then, the position correction amount (correction amount information) of the second head unit 20 is calculated from the read d1 and d2 according to the above equation (1), and the process proceeds to step S208.

In step S208, the position correction unit 92 controls the Y-axis motor 14 based on the position correction amount calculated in step S206. As a result, the second head unit 20 is moved in the transport width direction Y by a distance corresponding to the position correction amount in the direction corresponding to the position correction amount to correct the ink droplet ejection position, and the process proceeds to step S210.
In step S210, the controller 90 controls the driving of the nozzles of the second head unit 20 in accordance with the preset ejection timing, and ejects ink droplets onto the recording surface of the paper P, thereby performing step S212. Migrate to

  In step S212, the control unit 90 determines whether or not the ejection time (printing time) for one sheet of paper P has elapsed. If it is determined that the time has elapsed (Yes), the process proceeds to step S214. If not (No), the process proceeds to step S204. Instead of determining whether or not the ejection time has elapsed, a sensor that detects the end of the sheet P1 is provided to determine whether or not printing for the sheet P1 has been completed. good.

When the process proceeds to step S214, the controller 90 resets the first and second timers, and the process proceeds to step S216.
In step S216, the control unit 90 determines whether or not printing for the specified number of sheets designated by the print instruction has been completed. If it is determined that the printing has been completed (Yes), the series of processing is terminated, otherwise. In the case (No), the process proceeds to step S204.

Next, based on FIG.8 and FIG.9, operation | movement of the inkjet printer 100 of this embodiment is demonstrated.
Here, FIGS. 8A and 8B are diagrams showing examples of detection signals at the positions p1 and p2 of the edge of the paper P in the edge sensors S1 and S2, and FIG. 8C shows the positions of S1 and S2. It is a figure which shows the signal (p2-p1) of the difference of a detection signal. FIGS. 9A and 9B are diagrams for explaining the operation of correcting the relative displacement of the ejection position of the second head unit 20 with respect to the ejection position of the first head unit 10 on the paper P. FIG. .

When the power is turned on, the ink jet printer 100 executes an initialization operation for performing warm-up operation, checking for errors such as paper jam, resetting initial values of timers, deleting unnecessary data in the memory, and the like.
When a print instruction is received after the initialization operation, the control unit 90 first causes the edge sensors S1 and S2 to start detecting position information. Next, the control unit 90 causes the paper feed unit (not shown) and the transport unit 1 included in the ink jet printer 100 to start feeding and transporting the paper P based on the print instruction.

Next, the position correction unit 92 determines whether or not the end of the paper P is detected from the detection signal of the upstream edge sensor S1 (step S100). If it is determined that it has been detected ("Yes" branch in step S100), the first timer is started (step S102), the detected position p1 of the paper P edge (first position information p1), and the paper Based on the reference position rp of the P end, the first displacement d1 is calculated (step S104).
For example, it is assumed that the detection signal of the position p1 at the end of the paper P in the upstream edge sensor S1 is as shown in FIG. 8A with the horizontal axis as the time axis and the vertical axis as the paper position p1.

Here, as shown in FIG. 8A, the reference position rp of the paper P is set to “−0.01 [mm]”.
For example, when the position p1 is “0.004 [mm]” in the measurement time “0.1 [s]” of the first timer, the first positional deviation amount d1 is “d1 = p1−rp = 0”. .004-(− 0.01) = 0.014 [mm] ”.

Specifically, the position p1 of the end portion of the paper P in this case is an upper position in the transport width direction Y with respect to the reference position rp (dotted line in FIG. 9) as shown in (2) of FIG. The state is shifted to the direction side. In FIG. 9, the solid line is the position p1 of the end of the paper P detected by the edge sensor S1, and the alternate long and short dash line is the position p2 of the end of the paper P detected by the edge sensor S2. Further, black dots in FIG. 9 are dots formed by ejecting ink droplets from the first head unit 10, and gray dots are dots formed by ejecting ink droplets from the second head unit 20. 9A shows an ideal dot formation position (ink droplet ejection position) with respect to the reference position rp of the paper P. FIG.
That is, when the first positional deviation amount d1 is “0.014 [mm]”, the first head unit 10 d1 (0.014 [mm]) from the reference position rp to the end of the paper P. The ink droplets are ejected with a deviation.

For example, when the position p1 is “−0.016 [mm]” in the measurement time “0.2 [s]” of the first timer, the first positional deviation amount d1 is “d1 = p1− rp = −0.016 − (− 0.01) = − 0.006 [mm] ”.
Specifically, the position p1 of the end portion of the paper P in this case is lower in the transport width direction Y than the reference position rp (dotted line in FIG. 9), as shown in (2) of FIG. The state is shifted to the direction side.

Here, (1) in FIG. 9B shows an ideal dot formation position (ink droplet ejection position) with respect to the reference position rp of the paper P, similarly to (1) in FIG. That is, when the end portion of the sheet P is shifted d1 (0.006 [mm]) downward in the transport width direction Y, the first head unit 10 moves from the reference position rp in the direction opposite to the end side of the sheet P. Ink droplets are ejected with a deviation of d1 (0.006 [mm]).
When the first positional deviation amount d1 is calculated, the correction amount information generation unit 91 associates the calculated first positional deviation amount d1 with the measurement time (or count value) of the first timer, and the like. Are stored in the memory of the inkjet printer 100. Here, it is stored in the RAM of the control unit 90.

On the other hand, the control unit 90 controls the ejection head 11 of the first head unit 10 to eject ink droplets onto the paper P according to the measurement time of the first timer corresponding to the first displacement amount d1. That is, ink droplets are ejected from the first head unit 10 whose ejection position is fixed to the paper P whose end is shifted by d1 from the reference position.
The calculation and storage processing of the first misregistration amount d1 and the ink droplet ejection operation by the first head unit 10 are repeatedly performed at preset time intervals.
When the total ejection time required for printing the sheet P1 of the first head unit 10 has elapsed (“Yes” in step S110), when printing of the designated number of prints is completed (in step S110). “Yes” branch), a series of processing ends.

On the other hand, when printing of the designated number of prints has not been completed (“No” branch in step S110), the above-described series of processing (steps S100 to S110) is performed on the next paper P.
On the other hand, the position correction unit 92 determines whether or not the edge of the paper P is detected from the detection signal of the downstream edge sensor S2 (step S200). If it is determined that it has been detected ("Yes" branch of step S200), the second timer is started (step S202), the detected position P2 of the paper P edge (second position information p2), and the paper Based on the reference position rp of the P end, the second positional deviation amount d2 is calculated (step S204).

For example, assume that the detection signal of the position P2 at the end of the paper P in the downstream edge sensor S2 is as shown in FIG. 8B, with the horizontal axis as the time axis and the vertical axis as the paper position p2.
Here, as in FIG. 8A, the reference position rp of the paper P is set to “−0.01 [mm]”. For example, when the position p2 is “−0.013 [mm]” in the measurement time “0.1 [s]” of the second timer, the second positional deviation amount d2 is “d2 = p2−rp = −0.013 − (− 0.01) = − 0.003 [mm] ”.
Specifically, the position p2 of the end portion of the paper P in this case is lower in the transport width direction Y than the reference position rp (dotted line in FIG. 9) as shown in (3) of FIG. It becomes a state shifted by d2 (0.003 [mm]) in the direction side.

For example, when the position p2 is “0.018 [mm]” in the measurement time “0.2 [s]” of the second timer, the second positional deviation amount d2 is “d2 = p2−rp”. = 0.018 − (− 0.01) = 0.028 [mm] ”.
Specifically, the position p2 of the end portion of the paper P in this case is an upper position in the transport width direction Y with respect to the reference position rp (dotted line in FIG. 9), as shown in (3) of FIG. The direction is shifted by d2 (0.028 [mm]).
When the second displacement amount d2 is calculated, the correction amount information generation unit 91 stores the calculated second displacement amount d2 in the RAM in association with the measurement time (or count value) of the second timer. To do.

Next, the correction amount information generation unit 91 reads out the first positional deviation amount d1 and the second positional deviation amount d2 corresponding to the same measurement time from the RAM, and the second head unit 20 of the second head unit 20 according to the above equation (1). A position correction amount D is calculated (step S206).
For example, from “d1 = 0.014 [mm]” corresponding to the measurement time “0.01 [s]” and “d2 = −0.003 [mm]”, the position correction amount D is “ D = d2-d1 = −0.003−0.014 = −0.017 [mm] ”.

Then, the position correction unit 92 generates a control signal for controlling the Y-axis motor 14 based on the position correction amount D “D = −0.017 [mm]” calculated by the correction amount information generation unit 91. Is supplied to the Y-axis motor 14.
Here, in the examples of FIGS. 8A and 8B, when the detection position at the same time on the horizontal axis is viewed, the position p1 of the end of the paper P in the vicinity of the first head unit 10 is The position p2 of the end portion of the paper P in the vicinity of the two-head unit 20 changes in the reverse direction. Therefore, the relative position of the ejection position at the position p2 of the second head unit 20 with respect to the ejection position at the position p1 of the first head unit 10 changes as shown in FIG.

In the present embodiment, the first head unit 10 is fixed, the second head unit 20 is movable in the transport width direction Y, and the second head unit 20 with respect to the ink droplet ejection position on the paper P of the first head unit 10 is used. The relative deviation of the ink droplet ejection position is corrected.
That is, when the position correction amount D is “D = −0.017 [mm]”, the position correction unit 92 moves the second head unit 20 relative to the reference position hrp that is an ideal ink droplet ejection position. Then, a control signal for moving to a position separated by “0.017 [mm]” downward in the transport width direction Y is supplied to the Y-axis motor 14.

As a result, the second head unit 20 moves to a position away from the reference position hrp in the transport width direction Y by “0.017 [mm]” downward, and corresponds to the measurement time “0.01 [s]”. The position correction to be completed is completed (step S208).
When the position correction is completed, the control unit 90 then controls the ejection head 21 of the second head unit 20 to eject ink droplets onto the paper P (Step S210). That is, as shown in (4) of FIG. 9A, relative to the ink droplet ejection position of the first head unit 10 corresponding to the measurement time “0.01 [s]” on the paper P. Ink droplets are ejected from the second head unit 20 to the position where the positional deviation has been corrected.

Further, for example, from “d1 = −0.006 [mm]” corresponding to the measurement time “0.02 [s]” and “d2 = 0.028 [mm]”, the position correction amount D is , “D = d2−d1 = 0.028 − (− 0.006) = 0.034 [mm]” is calculated (step S206).
Accordingly, the position correction unit 92 moves a control signal for moving the second head unit 20 from the reference position hrp in the transport width direction Y to a position away by “0.034 [mm]” upward. To supply.

As a result, the second head unit 20 moves to a position away from the reference position hrp in the transport width direction Y by “0.034 [mm]” upward, corresponding to the measurement time “0.02 [s]”. The position correction to be completed is completed (step S208).
When the position correction is completed, the control unit 90 then controls the ejection head 21 of the second head unit 20 to eject ink droplets onto the paper P (Step S210). That is, as shown in (4) of FIG. 9B, relative to the ink droplet ejection position of the first head unit 10 corresponding to the measurement time “0.02 [s]” on the paper P. Ink droplets are ejected from the second head unit 20 to the position where the positional deviation has been corrected.
The calculation and storage processing of the second displacement amount d2, the calculation of the position correction amount D, the position correction of the second head unit 20, and the ink droplet ejection operation by the second head unit 20 are performed for a preset time. Repeated at intervals.

When the total ejection time required for printing the sheet P1 of the second head unit 20 has elapsed (“Yes” branch of step S112), the first and second timers are reset (step S214).
Further, when the printing of the number of prints designated by the print instruction has been completed (“Yes” branch of step S216), the series of processing is terminated.

On the other hand, when printing of the designated number of prints has not been completed (“No” branch of step S214), the above-described series of processing (steps S200 to S216) is performed on the next paper P.
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 amount of deviation from the reference position of the paper P in the vicinity of the ejection position of the first head unit 10 based on the detection result (first position information p1) of the upstream edge sensor S1. The first misregistration amount d1 is calculated. Next, based on the detection result (second position information p2) of the downstream edge sensor S2, the second position that is a deviation amount of the paper P from the reference position in the vicinity of the ejection position of the second head unit 20 is obtained. The shift amount d2 is calculated. Further, a position correction that is a relative deviation amount of the ejection position of the second head unit 20 with respect to the ejection position of the first head unit 10 relative to the paper P from the first positional deviation amount d1 and the second positional deviation amount d2. The quantity D is calculated. Based on the position correction amount D, the Y-axis motor 14 of the second head unit 20 is controlled to correct the position of the second head unit 20 and correct the relative deviation from the discharge position of the first head unit. To do. Thereafter, ink droplets are ejected from the second head unit 20 to record an image.

Accordingly, for example, when the position of the paper P changes in the transport width direction Y, the ink droplet ejection position of the second head unit 20 is corrected, and the ejection position of the first head unit 10 with respect to the paper P during printing is performed. The relative position of the discharge position of the second head unit 20 with respect to can be made constant. As a result, an image can be formed on the intended portion of the paper P, and an image that is difficult to see unevenness can be formed.
In the above embodiment, the components for reciprocating the second head unit 20 such as the Y-axis motor 14 and the guide rail in the transport width direction Y correspond to the head unit moving means.

In the above embodiment, the position information (first position information p1) of the edge of the paper P in the vicinity of the first head unit 10 is detected by the upstream edge sensor S1, the correction amount information generation unit 91, and the like. The element corresponds to the first position information detecting means.
In the above embodiment, the position information (second position information p2) of the edge of the paper P in the vicinity of the second head unit 20 is detected by the downstream edge sensor S1, the correction amount information generation unit 91, and the like. The element corresponds to the second position information detecting means.
In the above embodiment, the correction amount information generation unit 91 corresponds to a correction amount information generation unit, and the position correction unit 92 corresponds to a position correction unit.

Moreover, in the said embodiment, step S100 respond | corresponds to a 1st position information detection step, and step S200 respond | corresponds to a 2nd position information detection step.
In the above embodiment, steps S102 to S106 and steps S202 to 206 correspond to a correction amount information generation step, and step S208 corresponds to a position correction step.

In the above embodiment, at the time of printing, the first and second position information p1 and p2 are detected each time, and the first and second position information d1 and d2 are obtained from p1, p2 and the reference position rp. The position correction amount D is calculated from d1 and d2 and the position correction of the second head unit 20 is performed. However, the present invention is not limited to this structure.
For example, the position correction amount D for one sheet of paper P may be generated in advance using the periodicity of position fluctuation.
Specifically, the paper P transported on the transport surface 50 meanders while swinging in the transport width direction Y due to vibration of the transport mechanism and the like. The meandering of the paper P has the property of being repeated at the same period unless there is an external obstruction factor.

Therefore, by repeatedly performing the position correction using the correction amount information for one cycle, the ink droplet ejection position of the second head unit 20 from the start to the end of ink ejection (image formation end) can be corrected. it can.
That is, in the first time of test printing or actual printing, the first positional deviation amount d1 for P1 sheets is calculated and stored in association with the measurement time of the first timer, and the second timer is set. In association with the measurement time, the second positional deviation amount d2 for the sheet P1 is calculated and stored. Next, a position correction amount D for one sheet of paper P is calculated as correction amount information from the first and second positional deviation amounts d1 and d2 for one sheet of paper P, and this is stored in association with the measurement time of the timer. To do.

In actual printing or printing after the second sheet, the position correction of the second head unit 20 is performed using the position correction amount D (correction amount information) for one sheet of paper P stored in the memory in advance. At this time, based on the measurement time of the second timer and the measurement time associated with the position correction amount D, the position correction of the second head unit 20 is performed using the position correction amount D corresponding to the measurement time.
As a result, the correction amount information can be generated in advance before performing the position correction process, so that it is not necessary to perform the process of generating the correction amount information in real time every time during the printing process. It is possible to cope with the above with high accuracy.

In this configuration, since the problem of calculation speed is solved, the edge sensor S1 can be disposed directly below the first head unit 10 (for example, a position on the extended line of the ejection position), and the edge The sensor S2 can be disposed directly below the second head unit 20. Thereby, the accuracy of position correction can be improved.
Further, in this configuration, the moving unit is provided only on the first head unit 10, and the discharge position of the first head unit 10 is relative to the discharge position of the second head unit 20 with respect to the second head unit 20. It is also possible to adopt a configuration that corrects a general deviation.

In the above embodiment, the head unit corresponding to the four colors C, M, Y, and K is provided. However, the configuration is not limited to this, and the configuration corresponding to three or less colors (for example, one color) is used. Or a configuration corresponding to five or more ink colors including other colors such as LM (light magenta) and LC (light cyan).
Further, in the above-described embodiment, the printing unit 2 is configured with the head unit corresponding to each of the four colors C, M, Y, and K. However, the configuration is not limited to this configuration, and the head unit is configured with each color being independent. You may make it do. In this case, the same position correction as that of the second head unit 20 is performed on the head unit on the downstream side of the head unit located on the most upstream side.

In the above embodiment, the printing unit 2 has two head units corresponding to four colors of C, M, Y, and K. However, the arrangement is not limited to this configuration, and the arrangement of the ejection heads is changed. And it is good also as a structure which has three or more head units. Also in this case, the same position correction as that of the second head unit 20 is performed on the head unit on the downstream side of the head unit located on the most upstream side.
In the above embodiment, the second head unit 20 is configured to reciprocate in the transport width direction Y, and the reciprocation is controlled according to the periodic position fluctuation of the paper P in the transport width direction Y. Although it was set as the structure, it is not restricted to this structure.
For example, when the periodically changing direction of the paper P is a direction that is not orthogonal to the transport direction X, the second head unit 20 is configured to be able to reciprocate in that direction, and the position of the ejection position with respect to that direction It is good also as composition which performs amendment.

The above embodiments are preferable specific examples of the present invention, and various technically preferable limitations are given. However, the scope of the present invention is described in particular in the above description to limit the present invention. As long as there is no, it is not restricted to these forms. In the drawings used in the above description, for convenience of illustration, the vertical and horizontal scales of members or parts are schematic views different from actual ones.
Further, the present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Conveyance part, 2 ... Printing part, 10, 20 ... Head unit, 11, 21 ... Discharge head, 12, 22 ... Head panel, 14 ... Y axis motor, 31 ... Gate roller, 32 ... Driven roller, 33 ... Tension Roller, 34 ... Drive roller, 35 ... Endless belt, 36 ... Conveyance drive motor, 37 ... Air hole, 50 ... Conveyance surface, 90 ... Control unit, 91 ... Correction amount information generation unit, 92 ... Position correction unit, 100 ... Inkjet Printer, S1, S2 ... Edge sensor

Claims (7)

A transport unit that transports the recording medium, a first head unit that ejects ink droplets onto the recording medium transported by the transport unit, and the same posture as the first head unit and arranged in parallel in the transport direction. And a second head unit that ejects ink droplets onto a recording medium conveyed by the conveying means, and controls the first head unit and the second head unit to record an image on the recording medium. A recording position correcting device for correcting the recording position of the image of the recording device for recording,
Head unit moving means for moving the second head unit in a predetermined direction;
First position information detecting means for detecting position information of a recording medium conveyed by the conveying means in the vicinity of the ink droplet ejection position of the first head unit;
Second position information detecting means for detecting position information of a recording medium conveyed by the conveying means in the vicinity of the ink droplet ejection position of the second head unit;
The second head based on first position information that is position information detected by the first position information detection means and second position information that is position information detected by the second position information detection means. Correction amount information generating means for generating correction amount information that is a correction amount of the ejection position of the ink droplet of the unit;
Position correction means for controlling the head unit moving means based on the correction amount information generated by the correction amount information generating means to correct the ejection position of the second head unit;
The correction amount information generation unit corresponds to the displacement amount of the discharge position relative to the discharge position of the first head unit relative to the discharge position of the first head unit in the predetermined direction as the correction amount information. Information on the amount of correction to be performed,
The position correcting unit controls the head unit moving unit based on the correction amount information, so that the relative position of the second head unit in the predetermined direction with respect to the ejection position of the first head unit with respect to the recording medium. A recording position correction apparatus that corrects a deviation of a typical discharge position. The second head unit is disposed downstream of the first head unit in the transport direction,
The first position information detecting means detects position information of a recording medium conveyed by the conveying means on the upstream side of the first head unit;
The second position information detecting means detects position information of a recording medium conveyed by the conveying means on the downstream side of the first head unit and on the upstream side of the second head unit;
The correction amount information generating unit detects the predetermined amount of the second head unit relative to the discharge position of the first head unit with respect to the recording medium as the correction amount information every time the second position information is detected. The correction amount information corresponding to the displacement amount of the discharge position relative to the direction is sequentially generated,
The position correction unit controls the head unit moving unit each time the correction amount information is generated, so that the predetermined value of the second head unit with respect to the ejection position of the first head unit with respect to the recording medium. The recording position correction apparatus according to claim 1, wherein the displacement of the relative discharge position in the direction is sequentially corrected. The first position information detection means, as the first position information, position information that periodically changes in the predetermined direction at the upstream side of the first head unit or at the same position as the first head unit. Detect
The second position information detecting unit is configured to detect, as the second position information, a position downstream of the first head unit and upstream of the second head unit or the same position as the second head unit. Detecting position information periodically changing in the predetermined direction at
The correction amount information generation unit is configured to detect the first change with respect to a position change of one period of the recording medium based on the first position information and the second position information that change periodically as the correction amount information. Generating correction amount information corresponding to a displacement amount of the discharge position of the second head unit relative to the discharge position of the head unit with respect to the recording medium;
The position correcting means controls the head unit moving means based on correction amount information for the position fluctuation for the one period, and the second head unit relative to the ejection position of the first head unit with respect to the recording medium. The recording position correction apparatus according to claim 1, wherein a relative displacement of the discharge position in the predetermined direction is corrected.   4. The recording position correcting apparatus according to claim 1, wherein the predetermined direction includes a direction parallel to the transport surface and perpendicular to the transport direction. 5. A transport unit that transports the recording medium, a first head unit that ejects ink droplets onto the recording medium transported by the transport unit, and the same posture as the first head unit and arranged in parallel in the transport direction. And a second head unit that ejects ink droplets onto a recording medium conveyed by the conveying means, and controls the first head unit and the second head unit to record an image on the recording medium. A control program for a recording position correction apparatus for correcting the recording position of the image of the recording apparatus for recording,
The recording position correction apparatus includes a head unit moving unit that moves the second head unit in a predetermined direction, and a recording in which the vicinity of the ink droplet ejection position of the first head unit is conveyed by the conveying unit. First position information detecting means for detecting the position information of the medium, and second position information for detecting the position information of the recording medium conveyed by the conveying means in the vicinity of the ink droplet ejection position of the second head unit. And position information detecting means,
The second head based on first position information that is position information detected by the first position information detection means and second position information that is position information detected by the second position information detection means. A correction amount information generating step for generating correction amount information that is a correction amount of the ejection position of the ink droplet of the unit;
For causing a computer to execute processing including a position correction step of controlling the head unit moving unit based on the correction amount information generated in the correction amount information generation step to correct the ejection position of the second head unit. Including programs,
In the correction amount information generating step, as the correction amount information, a displacement amount of the discharge position relative to the discharge position of the first head unit with respect to the recording medium in the predetermined direction of the second head unit. Generate corresponding correction amount information,
In the position correction step, the head unit moving unit is controlled based on the correction amount information, and the second head unit in the predetermined direction with respect to the ejection position of the first head unit with respect to the recording medium. A control program for a recording position correction apparatus, which corrects a relative displacement of a discharge position. A transport unit that transports the recording medium, a first head unit that ejects ink droplets onto the recording medium transported by the transport unit, and the same posture as the first head unit and arranged in parallel in the transport direction. And a second head unit that ejects ink droplets onto a recording medium conveyed by the conveying means, and controls the first head unit and the second head unit to record an image on the recording medium. A control method of a recording position correction apparatus for correcting the recording position of the image of a recording apparatus for recording,
The recording position correction apparatus includes a head unit moving unit that moves the second head unit in a predetermined direction, and a recording in which the vicinity of the ink droplet ejection position of the first head unit is conveyed by the conveying unit. First position information detecting means for detecting the position information of the medium, and second position information for detecting the position information of the recording medium conveyed by the conveying means in the vicinity of the ink droplet ejection position of the second head unit. And position information detecting means,
The second head based on first position information that is position information detected by the first position information detection means and second position information that is position information detected by the second position information detection means. A correction amount information generating step for generating correction amount information that is a correction amount of the ejection position of the ink droplet of the unit;
A position correction step of controlling the head unit moving means based on the correction amount information generated in the correction amount information generation step to correct the ejection position of the second head unit,
In the correction amount information generating step, as the correction amount information, a displacement amount of the discharge position relative to the discharge position of the first head unit with respect to the recording medium in the predetermined direction of the second head unit. Generate corresponding correction amount information,
In the position correction step, the head unit moving unit is controlled based on the correction amount information, and the second head unit in the predetermined direction with respect to the ejection position of the first head unit with respect to the recording medium. A control method for a recording position correcting apparatus, wherein a relative displacement of a discharge position is corrected. Conveying means for conveying the recording medium;
A first head unit that ejects ink droplets onto a recording medium conveyed by the conveying means;
A second head unit that is disposed in parallel with the transport direction in the same posture as the first head unit and ejects ink droplets onto a recording medium transported by the transport means;
Image recording means for controlling the first head unit and the second head unit to record an image on the recording medium;
A recording apparatus comprising: the recording position correction apparatus according to claim 1.

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