JP2017077726A - Position correcting device, liquid emitting device, and position correcting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a position correcting device that is able to correct the position of a liquid emitting unit according to the position of an object being conveyed, and that is able to reduce fluctuation in landing interval.SOLUTION: A position correcting device that corrects the position of a liquid emitting unit 101 that emits a liquid to an object P being conveyed, comprises: a position detecting part 102 that detects the position of the object P in a width direction; a unit moving part 103 that moves the liquid emitting unit 101 in the width direction; a movement amount determination part that determines an amount of movement of the liquid emitting unit 101 in the width direction on the basis of the position of the object P in the width direction; a movement speed determination part that determines the speed of movement of the liquid emitting unit 101 corresponding to the speed of conveyance of the object P; and a movement control part that controls the unit movement part 103 so as to move the liquid emitting unit 101 in the width direction at the determined speed of movement and the determined amount of movement.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a position correction device, a liquid ejection device, and a position correction method.

  For example, an ink jet recording apparatus that forms an image on a long sheet by ejecting ink from a plurality of nozzles provided in a liquid ejection unit is known.

  In such an ink jet recording apparatus, deviation of the ink discharge position may occur due to the meandering or wrinkling of the paper, and color overlay accuracy may be reduced when a color image is formed by a plurality of liquid discharge units. .

  In view of this, a technique is disclosed in which an image is uniformly formed on a sheet by moving the liquid ejection unit based on conveyance information obtained from detection results of the edge positions of the sheet by a plurality of edge sensors (for example, patents). Reference 1).

  In the technique according to Patent Document 1, unevenness is reduced by obtaining a moving speed for moving the liquid discharge unit based on the positional displacement speed of the paper and moving the liquid discharge unit so that the relative position to the paper is constant. It is possible to form a processed image.

  Here, by forming a plurality of nozzle rows in the liquid ejection unit in which the plurality of nozzles are arranged in the paper width direction in the paper conveyance direction, it is possible to increase the nozzle density in the width direction and improve the image resolution. . In such a liquid discharge unit, nozzles that form dots adjacent in the paper width direction are spaced apart in the paper transport direction. For this reason, when the liquid ejection unit is moved in the width direction in accordance with the edge position of the paper during image formation, there may be unevenness in the interval between the landing positions of the dots adjacent in the paper width direction.

  If the liquid ejection unit is moved in accordance with the sheet displacement speed as in the technique according to Patent Document 1 described above, there is a possibility that unevenness in dot spacing in the width direction increases when the sheet conveyance speed changes. is there.

  The present invention has been made in view of the above, and an object of the present invention is to provide a position correction device that corrects the position of the liquid discharge unit in accordance with the transfer position of the transferred object and can reduce unevenness in landing intervals. And

  According to one aspect of the present invention, a position correction device that corrects the position of a liquid ejection unit that ejects liquid onto a conveyed object to be conveyed, the position detection unit detecting a position in the width direction of the conveyed object A unit moving unit that moves the liquid discharge unit in the width direction; and a movement amount determination unit that determines a movement amount of the liquid discharge unit in the width direction based on a position in the width direction of the transported object. A moving speed determining unit that determines a moving speed of the liquid discharge unit according to a transfer speed of the object to be transferred, and the liquid discharge unit to move in the width direction at the moving speed and the moving amount. A movement control unit for controlling the unit moving unit.

  According to the embodiment of the present invention, there is provided a position correction device capable of correcting the position of the liquid discharge unit in accordance with the transfer position of the object to be transferred and reducing unevenness in landing intervals.

It is a figure which illustrates the liquid discharge system in embodiment. It is a figure which illustrates the structure of the liquid discharge apparatus in embodiment. It is a figure which illustrates the liquid discharge unit in embodiment. It is a figure which illustrates the liquid discharge head in embodiment. It is a figure which illustrates the liquid discharge area | region on a paper. It is a figure which illustrates the hardware constitutions of the liquid discharge apparatus in embodiment. It is a figure which illustrates the function structure of the position correction apparatus in embodiment. It is a figure explaining position correction of a liquid discharge unit in an embodiment. FIG. 10 is a diagram illustrating a relationship between a sheet conveyance distance and a movement distance of the liquid discharge unit when the movement speed of the liquid discharge unit is constant. It is a figure which illustrates the liquid discharge area | region on a paper. It is a figure which illustrates the relationship between the paper conveyance distance and the movement distance of a liquid discharge unit in embodiment. It is a figure which illustrates the flowchart of position correction control in embodiment. It is a figure which illustrates the hardware constitutions of the sensor in embodiment. It is a figure which illustrates the functional structure of the sensor in embodiment. It is an external view which illustrates the sensor in an embodiment. It is a figure explaining arrangement | positioning of the sensor in embodiment.

  Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and redundant description may be omitted.

<Liquid discharge system>
FIG. 1 is a diagram illustrating a liquid ejection system 10 according to an embodiment.

  As shown in FIG. 1, the liquid ejection system 10 includes a first liquid ejection device 100a, a second liquid ejection device 100b, a paper feeding device 300, a processing agent application device 400, and a reversing device 500. The first liquid ejection device 100a and the second liquid ejection device 100b in this embodiment are devices that eject liquid by driving a liquid ejection head, respectively. The liquid ejecting apparatus includes not only an apparatus capable of ejecting a liquid to an object to which the liquid can adhere, but also an apparatus that ejects the liquid toward the air or liquid. In the following description, the first liquid ejecting apparatus 100a and the second liquid ejecting apparatus 100b having the same configuration may be simply referred to as the liquid ejecting apparatus 100 with the reference numerals omitted.

  The first liquid ejecting apparatus 100a forms an image by ejecting ink droplets onto the first surface of the paper P, which is fed from the paper feeding device 300 and has the processing agent applied to both sides in the processing agent applying apparatus 400. The paper P as a recording medium is a long continuous paper, is wound in a roll shape, is stored in the paper feeding device 300, and is fed from the paper feeding device 300 to the processing agent coating device 400 by a supply roller or the like.

  The second liquid ejecting apparatus 100b forms an image by ejecting ink droplets onto the second surface of the paper P on which the first liquid ejecting apparatus 100a forms an image on the first surface and the front and back surfaces are reversed by the reversing device 500. To do.

  The liquid ejection system 10 has the above-described configuration, and forms images on both sides of a long sheet P by the first liquid ejection device 100a and the second liquid ejection device 100b. The liquid discharge system 10 may include a cutting device that cuts the paper P discharged from the second liquid discharge device 100b, a post-processing device that performs post-processing of the cut paper P, and the like.

  Although the first liquid ejection device 100a and the second liquid ejection device 100b in the present embodiment eject ink droplets as liquid, the liquid ejected is not limited to ink droplets. The liquid ejected by the first liquid ejecting apparatus 100a and the second liquid ejecting apparatus 100b may have any viscosity or surface tension that can be ejected from the head. Specifically, solvents such as water and organic solvents, colorants such as dyes and pigments, functional compounds such as polymerizable compounds, resins, and surfactants, biocompatible materials such as DNA, amino acids, proteins, and calcium, These include solutions, suspensions, emulsions and the like containing edible materials such as natural pigments. The liquid ejected from the first liquid ejecting apparatus 100a and the second liquid ejecting apparatus 100b includes inkjet ink, surface treatment liquid, components for electronic elements and light emitting elements, liquid for forming an electronic circuit resist pattern, and three-dimensional modeling. Used in applications such as material liquids.

  The transported object transported by the first liquid ejecting apparatus 100a and the second liquid ejecting apparatus 100b only needs to be capable of adhering liquid, and is capable of at least temporarily adhering liquid. It may be a thing that adheres and a thing that adheres and penetrates. Specifically, media such as recording media such as paper, recording paper, recording paper, film, cloth, electronic parts such as electronic substrates, piezoelectric elements, powder layers (powder layers), organ models, examination cells, etc. The liquid is not limited as long as it adheres.

<Liquid ejection device>
FIG. 2 is a diagram illustrating the configuration of the liquid ejection apparatus 100 according to the embodiment.

  As shown in FIG. 2, the liquid ejection apparatus 100 includes a liquid ejection unit 101K, a liquid ejection unit 101C, a liquid ejection unit 101M, and a liquid ejection unit 101Y in order from the upstream side in the transport direction of the sheet P. It is provided along the conveyance path. The symbols K, C, M, and Y represent black, cyan, magenta, and yellow, respectively, and each liquid ejection unit 101 ejects ink droplets of the color represented by the symbols to form a full-color image on the paper P. To do. In the following description, reference numerals may be omitted.

  Each liquid discharge unit 101 includes a plurality of liquid discharge heads that are arranged in a width direction orthogonal to the transport direction of the paper P and each have a nozzle row that discharges ink droplets, and forms an image over the entire width of the paper P in a so-called one pass. it can. The liquid discharge unit 101 is, for example, a unit in which functional parts and mechanisms are integrated with a liquid discharge head. The liquid discharge unit 101 includes, for example, at least one of a head tank, a carriage, a supply mechanism, a maintenance / recovery mechanism, and a main scanning movement mechanism, and a liquid discharge head.

  An edge sensor 102 that detects the end position of the paper P is provided on the upstream side of each liquid discharge unit 101 in the transport direction. The edge sensor 102 is a CIS (contact image sensor), for example, and is provided in a region through which an end in the width direction orthogonal to the conveyance direction of the paper P passes. Based on the output of the edge sensor 102, the position in the width direction end of the paper P before passing through the ejection position of each liquid ejection unit 101 is detected.

  Further, the liquid discharge units 101C, 101M, and 101Y provided on the downstream side of the liquid discharge unit 101K can be moved in the width direction orthogonal to the transport direction of the paper P by the actuators 103C, 103M, and 103Y connected thereto. Is provided. The actuator 103 includes, for example, a servo motor, and the rotation of the servo motor is converted into a linear motion by a ball screw mechanism to move the liquid discharge unit 101 in the width direction.

  In the liquid discharge units 101C, 101M, and 101Y, the actuators 103 are driven based on the edge position detection results of the paper P detected from the outputs of the edge sensors 102 so as to match the liquid discharge position of the liquid discharge unit 101K. Move in the width direction.

  In addition, an actuator 103K is provided in the liquid discharge unit 101K, and the liquid discharge unit 101K is moved in the width direction by driving the actuator 103K based on the width direction end position of the paper P detected from the output of the edge sensor 102K. Also good.

  FIG. 3 is a diagram illustrating the liquid discharge unit 101 in the embodiment. FIG. 4 is a diagram illustrating a liquid discharge head 110 provided in the liquid discharge unit 101.

  As shown in FIG. 3, the liquid discharge unit 101 includes a plurality of liquid discharge heads 110 arranged in a staggered manner. Each liquid discharge head 110 includes a first liquid discharge head 111 and a second liquid discharge head 113 as shown in FIG.

  The first liquid ejection head 111 is provided with a plurality of nozzles 112 that eject ink droplets onto the surface of the paper P to form dots as liquid ejection elements as a liquid ejection section. The first liquid discharge head 111 is provided with four nozzle rows in the transport direction in which a plurality of nozzles 112 are arranged in the width direction.

  Further, the second liquid ejection head 113 is provided with a plurality of nozzles 114 that eject ink droplets onto the surface of the paper P to form dots as liquid ejection elements as a liquid ejection unit. Similar to the first liquid ejection head 111, the second liquid ejection head 113 is provided with four nozzle rows in the transport direction in which a plurality of nozzles are arranged in the width direction.

  The plurality of nozzles 112 and 114 provided in the first liquid discharge head 111 and the second liquid discharge head 113 are formed such that their center positions are slightly shifted in the width direction. FIG. 5 illustrates a liquid discharge area formed by the nozzle 112a provided at the top of the first liquid discharge head 111 and the nozzle 114a provided at the top of the second liquid discharge head 113 in FIG.

  As shown in FIG. 5, the nozzle 112 a of the first liquid discharge head 111 and the nozzle 114 a of the second liquid discharge head 113 discharge ink droplets at positions adjacent to each other in the width direction on the surface of the paper P. Form. FIG. 5 shows a liquid ejection region formed by landing ink droplets ejected from the nozzle 112a on the paper, and a liquid ejection region formed by landing ink droplets ejected from the nozzle 114a on the paper. Are shown by shading with different concentrations. Note that the liquid ejection region of the nozzle 112 of the first liquid ejection head 111 and the liquid ejection region of the nozzle 114 of the second liquid ejection head 113 may partially overlap in the width direction on the surface of the paper P.

  Thus, the center positions of the plurality of nozzles 112 provided in the first liquid discharge head 111 and the plurality of nozzles 114 provided in the second liquid discharge head 113 are slightly shifted in the width direction. Is formed. In other words, a plurality of nozzles are arranged in each of the liquid ejection heads 111 and 113 such that nozzles that form dots as liquid ejection elements are spaced apart in the transport direction at positions adjacent to each other in the width direction of the paper P.

  In the liquid discharge unit 101, the liquid discharge heads 110 that form images in predetermined areas in the width direction are arranged in a staggered manner in the above-described configuration, and images can be formed in the entire width in the width direction of the paper P without gaps. The liquid discharge unit 101 in the present embodiment has an improved nozzle density in the width direction by the above-described configuration, and can form a high-resolution image on the paper P.

  Note that the configurations of the number and positions of the liquid discharge heads 110 provided in the liquid discharge unit 101 and the number and positions of the nozzles provided in the liquid discharge head 110 are limited to the configurations exemplified in this embodiment. It is not a thing.

[Hardware configuration]
FIG. 6 is a diagram illustrating a hardware configuration of the liquid ejection apparatus 100 according to the embodiment.

  As illustrated in FIG. 6, the liquid ejection device 100 includes a liquid ejection unit 101, a transport roller 120, an encoder 121, and a position correction device 150.

  The liquid ejection unit 101 has the above-described configuration, and forms an image by ejecting ink droplets onto the surface of the paper P based on image data input to the liquid ejection device 100. The liquid ejecting apparatus 100 includes a liquid ejecting unit 101 that forms images of each color of Y, M, C, and K, and forms a full color image by superimposing the images of each color on the surface of the paper P.

  The transport roller 120 is, for example, a roller pair in which one is rotationally driven and the other is driven and rotated, and the paper P is sandwiched and transported between the roller pair. The transport roller 120 has a variable transport speed of the paper P, and transports the paper P at any one of three transport speeds, for example, low speed, medium speed, and high speed.

  The encoder 121 is provided, for example, on the rotation shaft of the driven roller of the transport roller 120 and outputs a transport signal (6 ppi signal) every time the transport roller 120 transports the paper P by 1/6 inch which is the detection distance.

  The transport roller 120 and the encoder 121 are an example of a transport unit that transports the paper P in the liquid ejection apparatus 100. The transport unit is not limited to the configuration exemplified in this embodiment as long as a transport signal can be output every time the paper P is transported by a predetermined distance.

  The position correction device 150 includes an edge sensor 102, an actuator 103, a CPU 151, a RAM 152, a ROM 153, a timer 154, a controller 155, and a speed detection circuit 156, and each unit is connected via a bus B.

  As described above, the edge sensor 102 is provided on the upstream side of each of the liquid ejection units 101C, 101M, and 101Y in the transport direction of the paper P. The actuator 103 is connected to each of the liquid discharge units 101C, 101M, and 101Y, and is driven under the control of the controller 155, thereby moving each liquid discharge unit 101 in the width direction.

  The ROM 153 stores various programs and data used by the programs. The RAM 152 is used as a storage area for loading a program, a work area for the loaded program, and the like. The CPU 151 realizes various functions by processing a program loaded in the RAM 152.

  The timer 154 is used, for example, for detecting the conveyance speed of the paper P in the liquid ejection apparatus 100.

  The controller 155 controls the actuator 103 so as to move the liquid discharge unit 101 in the width direction based on the movement amount obtained from the width direction end position of the paper P detected from the output of the edge sensor 102. Further, the controller 155 controls the actuator 103 so as to move the liquid ejection unit 101 at a moving speed set based on the conveyance speed of the paper P detected from the output of the encoder 121.

  The speed detection circuit 156 is a circuit that detects the transport speed of the paper P by the transport roller 120 based on the transport signal output from the encoder 121.

[Function configuration]
FIG. 7 is a diagram illustrating a functional configuration of the position correction apparatus 150 in the embodiment.

  As illustrated in FIG. 7, the position correction apparatus 150 includes a position detection unit 161, a movement amount determination unit 162, a conveyance speed detection unit 163, a movement speed determination unit 164, and a movement control unit 165.

  The position detection unit 161 detects the position in the width direction end of the paper P based on the output of the edge sensor 102. The movement amount determination unit 162 determines the movement amount of the liquid ejection unit 101 in the width direction based on the width direction end portion position of the paper P detected by the position detection unit 161.

  The conveyance speed detection unit 163 acquires the conveyance speed of the paper P by the conveyance roller 120 detected by the speed detection circuit 156. Further, the transport speed detection unit 163 may acquire the transport signal output from the encoder 121 and measure the transport signal interval using the timer 154 to detect the transport speed of the paper P.

  The movement speed determination unit 164 determines the movement speed of the liquid ejection unit 101 based on the conveyance speed of the paper P detected by the conveyance speed detection unit 163.

  The movement control unit 165 sets the movement speed determined by the movement speed determination unit 164 and the movement amount determined by the movement amount determination unit 162 in the controller 155. Each liquid discharge unit 101 moves in the width direction at a set moving speed and moving amount by driving the actuator 103 under the control of the controller 155.

(Liquid discharge unit position correction)
Next, a method in which the movement amount determination unit 162 determines the movement amount in the width direction of the liquid ejection unit 101 will be described with reference to FIG.

When an image is formed on the paper P conveyed by the liquid ejection apparatus 100, first, the position detection unit 161 acquires the output value of the edge sensor 102K, and the edge in the width direction of the paper P at the detection position of the edge sensor 102K. detecting the part position CS _K. The moving amount determination unit 162, from the difference between the end position CS _K and the reference position RS _K of the sheet P at the detection position of the edge sensors 102K, obtaining the positional displacement amount _{d K (= CS K -RS K} ).

Next, the position detecting unit 161 obtains the output value of the edge sensor 102C, detects the edge position CS _C in the width direction of the sheet P at the detection position of the edge sensor 102C. The moving amount determination unit 162, from the difference between the end position CS _C and the reference position RS _C of the paper P at the detection position of the edge sensor 102C, obtaining the positional displacement amount _{d C (= CS C -RS C} ).

Movement amount determination unit 162 calculates a difference between the position deviation amount _{d C} a positional deviation amount _{d K,} the relative positions of the liquid discharge unit 101K and the liquid discharge unit 101C deviation amount _D C ₍₌ d C -d _K ) Movement amount determination unit 162, the calculated relative positional deviation amount D _C, the amount of movement of the width direction of the liquid discharge unit 101C.

Movement control unit 165, by moving the liquid discharge unit 101C from the reference position ra _C only the relative positional deviation amount _{D C,} to align the liquid discharge position of the liquid discharge unit 101C, the liquid discharge position of the liquid ejection units 101K Can do.

  The reference position ra of each liquid discharge unit 101 is the actuator 103 in which the liquid discharge position in the width direction of each liquid discharge unit 101 coincides when the edge position of the paper P at the detection position of each edge sensor 102 is rs. Control position.

Movement amount determination unit 162, similarly, the liquid discharge unit 101M, 101Y and relative positional deviation amount _D M of the liquid ejection units 101K, seek _{D Y,} which liquid discharge unit 101M, the amount of movement of the width direction 101Y And The movement control unit 165 moves each of the liquid discharge units 101M and 101Y by the determined movement amount, and adjusts the liquid discharge position in the width direction.

  As described above, the movement amount determination unit 162 determines the movement amount with reference to the width direction end portion position of the paper P at the detection position of the edge sensor 102K, and the movement control unit 165 determines the width of each liquid ejection unit 101. Move in the direction.

  In the present embodiment, the liquid discharge units 101C, 101M, and 101Y are moved so as to match the position of the liquid discharge unit 101K with reference to the position in the width direction end of the paper P at the detection position of the edge sensor 102K. As described above, the liquid ejection units 101 move so that the liquid ejection positions coincide with each other in the width direction, thereby preventing the positional deviation of the images of the respective colors formed on the paper P.

  If it is possible to match the liquid discharge positions of the respective colors formed on the paper P, the liquid discharge unit 101 may be moved to match the position in the width direction of the liquid discharge unit 101 on the upstream side, for example. Good.

  For example, the relative displacement amount D with respect to the liquid ejection unit 101C obtained based on the outputs of the edge sensors 102C and 102M is used as the movement amount, and the liquid ejection unit 101M is moved to match the position in the width direction of the liquid ejection unit 101C. May be. In this case, the relative displacement amount D with respect to the liquid ejection unit 101C obtained based on the outputs of the edge sensors 102M and 102Y is used as the movement amount so that the liquid ejection unit 101Y is aligned with the width direction position of the liquid ejection unit 101M. Move to.

(Liquid discharge unit moving speed)
Next, the moving speed of the liquid discharge unit 101 will be described.

  FIG. 9 is a diagram illustrating the relationship between the sheet conveyance distance and the movement distance of the liquid discharge unit 101 when the movement speed of the liquid discharge unit 101 is constant.

  When the moving speed of the liquid discharge unit 101 in the width direction is constant, as illustrated in FIG. 9, the relationship between the sheet conveying distance and the moving distance varies depending on the sheet P conveying speed. For example, when the sheet P is being conveyed at high speed, the sheet P is conveyed by 1 inch while the liquid ejection unit 101 moves a predetermined distance (5 μm). On the other hand, when the paper P is being transported at a medium speed and at a low speed, the transport distance of the paper P while the liquid discharge unit 101 moves by a predetermined distance is 0.6 inches and 0.2 inches, respectively. Shorter.

  FIG. 10 is a diagram illustrating a liquid discharge area on a sheet. In FIG. 10, a liquid ejection region formed by landing of ink droplets ejected from the nozzles 112 a of the first liquid ejection head 111 and an ink droplet ejected from the nozzles 114 a of the second liquid ejection head 113 are landed. The liquid discharge region formed by doing so is indicated by shading with different concentrations.

  FIG. 10A illustrates an area where the nozzles 112a and 114a form an image on the paper P when the paper P is being conveyed at high speed. As shown in FIG. 10A, it is assumed that the sheet P is conveyed at a high speed by the distance D1 while the liquid ejection unit 101 moves the distance H in the width direction.

  Here, the nozzle 112a and the nozzle 114a are formed at positions separated in the transport direction. Accordingly, when the liquid discharge unit 101 moves in the width direction, a slight gap is formed between the liquid discharge region by the nozzle 112a and the liquid discharge region by the nozzle 114a, as shown in FIG.

  FIG. 10B illustrates an area in which the nozzles 112a and 114a form an image on the paper P when the paper P is being conveyed at low speed. As shown in FIG. 10B, it is assumed that the sheet P is conveyed at a low speed by the distance D2 (<D1) while the liquid discharge unit 101 moves the distance H in the width direction.

  When the paper P is transported at a low speed, the transport distance of the paper P while the liquid ejection unit 101 moves in the width direction is shorter than that during the high speed transport. For this reason, the liquid discharge areas of the nozzles 112a and 114a change on the paper P so that they are displaced more rapidly in the width direction than during high-speed conveyance. Therefore, the gap between the liquid ejection area by the nozzle 112a and the liquid ejection area by the nozzle 114a during low-speed conveyance has a different shape from that during high-speed conveyance, and unevenness in landing intervals in the image formed on the paper P seems to have increased. May appear.

  Therefore, in the present embodiment, as illustrated in FIG. 11, while the moving speed determination unit 164 is transporting the paper P a predetermined control distance (for example, 1 inch), the liquid ejection unit 101 is a predetermined moving distance. The moving speed is determined so as to move by (for example, 5 μm).

  When the movement speed determination unit 164 determines the movement speed as described above, the relationship between the movement distance of the liquid ejection unit 101 and the conveyance distance of the paper P is the conveyance speed of the paper P as shown in FIG. Regardless, it is constant.

  In FIG. 11, when the paper P is transported at a low speed or a medium speed, the paper P is transported by 1 inch while the liquid discharge unit 101 moves 5 μm in the width direction, as in the case of the high speed transport. The result of obtaining the moving speed is illustrated.

  In the present embodiment, the movement control unit 165 performs position correction control of the liquid ejection unit 101 every time the paper P is transported a predetermined control distance. For this reason, the liquid discharge unit 101 can be moved and moved by the maximum movement distance while the paper P is being transported at a high speed so that the position can be corrected even during high-speed transport of the paper P. The moving speed of the unit 101 is set.

  By setting the moving speed in this manner, while the paper P is being transported within a predetermined range in the width direction, the liquid discharge unit 101 is kept in a state where the paper P is transported by a predetermined control distance regardless of the transport speed. Position correction control can be completed. Note that the maximum movement distance of the liquid discharge unit 101 is set based on, for example, a conveyance position shift amount in the width direction of the paper P, for example.

  In this embodiment, the moving speed of the liquid discharge unit 101 changes according to the transport speed of the paper P, so that the liquid discharge area by the nozzles 1121 and 114a is when the transport speed of the paper P is low and medium. This is the same as that at the time of high-speed conveyance shown in FIG. As described above, the gaps between the liquid ejection regions of the nozzles adjacent in the width direction have the same shape regardless of the conveyance speed of the paper P, so that unevenness in the landing interval of the ink droplets is increased depending on the conveyance speed. Thus, it is possible to suppress unevenness in the landing interval of the ink droplets on the paper P.

  Note that the movement amount of the liquid discharge unit 101 in the width direction is a minute distance, and the liquid discharge unit 101 may reach the set movement amount before reaching the set movement speed. Therefore, the moving speed determination unit 164 may obtain the acceleration together with the moving speed of the liquid discharge unit 101 so that the liquid discharge unit 101 moves by a predetermined distance while the paper P is transported a predetermined control distance. .

  In this case, the movement control unit 165 sets the movement speed and acceleration determined by the movement speed determination unit 164 in the controller 155, and moves the liquid ejection unit 101 at the movement speed and acceleration determined by the movement speed determination unit 164. To control.

<Position correction control processing>
FIG. 12 is a diagram illustrating a flowchart of the position correction control process in the embodiment.

  When the power of the liquid ejection apparatus 100 is turned on, first, initialization at the time of turning on the power is performed in step S101. As initialization when the power is turned on, for example, position adjustment of the liquid discharge unit 101 by the actuator 103, output confirmation of the edge sensor 102, and the like are performed. When initialization at the time of power ON is completed, each part such as the transport roller 120 of the liquid ejection apparatus 100 is set in a transport start waiting state in step S102.

  When conveyance of the paper P is started in the liquid ejection apparatus 100 (step S103: YES), the conveyance speed detection unit 163 outputs a conveyance signal output from the encoder 121 provided on the conveyance roller 120 to the speed detection circuit 156. Start measuring the time interval.

  For example, when the interval of the conveyance signal output from the encoder 121 is constant for a predetermined time (step S105: YES), the conveyance speed detection unit 163 is detected by the speed detection circuit 156 in step S106. The conveyance speed of the paper P is acquired.

  Next, in step S <b> 107, the movement speed determination unit 164 determines the movement speed of the liquid ejection unit 101 based on the conveyance speed of the paper P detected by the conveyance speed detection unit 163. As described above, the movement speed determination unit 164 determines the movement speed so that the liquid ejection unit 101 moves by a predetermined movement distance while the paper P is conveyed through the control distance at the detected conveyance speed.

  In step S <b> 108, the movement control unit 165 sets the movement speed determined by the movement speed determination unit 164 in the controller 155. In step S109, the movement control unit 165 determines whether it is the position correction control timing of the liquid ejection unit 101.

  In the present embodiment, the position correction control of the liquid ejection unit 101 is executed every time the paper P is conveyed by a predetermined control distance (for example, 1 inch). The movement control unit 165 conveys the paper P by a predetermined conveyance distance from the conveyance start timing or the previous position correction control timing based on the conveyance signal output from the encoder 121 provided to the conveyance roller 120 to the speed detection circuit 156. It is judged whether it was done. If it is the position correction control timing of the liquid ejection unit 101 (step S109: YES), the process proceeds to step S110.

  In step S110, the conveyance speed detection unit 163 determines whether or not the time interval of the conveyance signal being measured is constant. If the time interval of the carrier signal is not constant (step S110: NO), the processing after step S105 is executed. If the time interval of the transport signal is constant, the movement control unit 165 determines whether the transport of the paper P has been stopped in step S111.

  When the paper P is being conveyed (step S111: YES), position correction control of the liquid ejection unit 101 is performed in step S112. Specifically, the liquid ejection unit 101 has a width such that the movement amount determined by the movement speed determination unit 164 moves by the movement amount determined based on the end position of the paper P by the movement amount determination unit 162. Move in the direction.

  The position correction control is executed when the paper P is being conveyed at a constant speed (step S110: YES). When the conveyance speed of the paper P changes (step S110: NO), the movement speed is determined again after the conveyance speed of the paper P becomes constant, and the head position correction control is executed based on the determined movement speed. Is done.

  The position correction control of the liquid discharge unit 101 is repeatedly executed at the position correction control timing while the paper P is being transported at a constant speed at the set transport speed, and the liquid discharge position of each liquid discharge unit 101 is corrected. This suppresses color misregistration.

  If the conveyance of the paper P is stopped (step S111: YES), the process proceeds to step S113. If the conveyance of the paper P is stopped and the power of the liquid ejecting apparatus 100 is not turned off (step S113: NO), the processing after step S102 is executed. When the conveyance of the paper P is stopped and the power of the liquid ejection apparatus 100 is turned off (step S113: YES), the position correction control process is ended.

  As described above, in the liquid ejection apparatus 100 according to the present embodiment, the movement speed in the width direction of the liquid ejection unit 101 is controlled to change according to the conveyance speed of the paper P. In the present embodiment, as described above, in the width direction of the liquid ejection unit 101, the relationship between the transport distance of the paper P and the movement distance of the liquid discharge unit 101 is constant regardless of the transport speed of the paper P. The moving speed is controlled. By controlling the movement speed of the liquid discharge unit 101 in this way, the gap between the liquid discharge areas of the nozzles that form dots at adjacent positions in the width direction when the liquid discharge unit 101 is moved becomes constant. It is possible to suppress unevenness in the landing interval.

  In the above-described embodiment, the case where the image is formed by ejecting the liquid on the long sheet P is exemplified. However, the liquid may be ejected on a sheet, for example. Further, the liquid ejecting apparatus is not limited to the one in which significant images such as characters and figures are visualized by the ejected liquid. For example, what forms a pattern etc. which does not have a meaning in itself, and what forms a three-dimensional image are also included.

  In the above-described embodiment, the edge position of the sheet P in the width direction is detected by the edge sensor 102. However, the position in the width direction of the sheet P may be detected by the sensor 200 described below.

  FIG. 13 is a diagram illustrating a hardware configuration of the sensor 200 in the embodiment.

  As illustrated in FIG. 13, the sensor 200 includes a detection device 50, a first light source 51 </ b> A, a second light source 51 </ b> B, a control device 52, a storage device 53, and a calculation device 54.

  The first light source 51 </ b> A and the second light source 51 </ b> B have a light emitting element that emits laser light and a collimator lens that makes the laser light emitted from the light emitting element substantially parallel, and irradiates the surface of the paper P with the laser light. To do. The light emitting elements provided in the first light source 51A and the second light source 51B are, for example, LDs, LEDs, and the like.

  The first light source 51 </ b> A and the second light source 51 </ b> B are provided at positions where the laser light is irradiated obliquely with respect to the surface of the paper P. A position where the first light source 51A irradiates the paper P with the laser light is referred to as an “A position”. The position at which the second light source 51B irradiates the paper P with laser light is referred to as “B position”.

  The detection device 50 includes the area sensor 11, the first imaging lens 12A provided at a position facing the “A position”, and the second imaging lens 12B provided at a position facing the “B position”. Have.

  The area sensor 11 includes an image sensor 132 provided on a silicon substrate 131 and is accommodated in the housing 13. The image sensor 132 has an “A region 11A” and a “B region 11B” for acquiring a two-dimensional image. The area sensor 11 is, for example, a CCD sensor, a CMOS sensor, a photodiode array, or the like.

  The first imaging lens 12 </ b> A is held by the first lens barrel 13 </ b> A, and is provided so that the optical axis coincides with the center of the “A region 11 </ b> A” of the imaging device 132. The first imaging lens 12 </ b> A focuses light on the “A region 11 </ b> A” of the imaging element 132. The second imaging lens 12B is held by the second lens barrel 13B, and is provided so that the optical axis coincides with the center of the “B region 11B” of the imaging element 132. The second imaging lens 12 </ b> B focuses light on the “B region 11 </ b> B” of the imaging element 132. The first imaging lens 12A and the second imaging lens 12B are zoom lenses ZM that can change the optical zoom magnification when the position or the like is changed.

  The first imaging lens 12A is provided with a zoom mechanism including an actuator ACA. The second imaging lens 12B is provided with a zoom mechanism including an actuator ACB. For example, when the optical zoom magnifications of the first imaging lens 12A and the second imaging lens 12B are changed, the positions of the first imaging lens 12A and the second imaging lens 12B so that each zoom mechanism has the set optical zoom magnification. To change.

  The first imaging lens 12A and the second imaging lens 12B may be provided with a shutter or the like that can control the aperture and the shutter speed.

  In the detection device 50, the first imaging lens 12A and the second imaging lens 12B may be integrally formed. In this case, it is preferable to provide an aperture or the like for restricting each imaging region between the area sensor 11 so that images from the first imaging lens 12A and the second imaging lens 12B do not interfere with each other.

  In the detection device 50, a plurality of imaging elements 132 may be provided on the silicon substrate 131 of the area sensor 11. In this case, the image sensor 132 is provided at a position where the light from the first imaging lens 12A forms an image and a position where the light from the second imaging lens 12B forms an image, respectively.

  The control device 52 of the sensor 200 controls the detection device 50 and the like. For example, the control device 52 transmits a signal to the detection device 50 to control the shutter timing of the area sensor 11. In addition, the control device 52 acquires a two-dimensional image from the detection device 50 and sends the acquired two-dimensional image to the storage device 53.

  The storage device 53 is a memory, for example, and stores a two-dimensional image sent from the control device 52. The storage device 53 divides a two-dimensional image, for example, and stores it in different storage areas.

  The arithmetic device 54 is, for example, a microcomputer, and executes various processes using image data stored in the storage device 53.

  The control device 52 and the arithmetic device 54 are configured to include, for example, a CPU and an electronic circuit, respectively. Moreover, the control apparatus 52 and the arithmetic unit 54 may be comprised including the same CPU.

  FIG. 14 is a diagram illustrating a functional configuration of the sensor 200 in the embodiment. Hereinafter, among the sensors 200 provided for each liquid discharge unit 101, a combination of a black liquid discharge unit 101K and a cyan liquid discharge unit 101C will be described as an example.

  In the configuration shown in FIG. 14, the detection unit 60A for the black liquid ejection unit 101K outputs the detection result of “A position”, and the detection unit 60B for the cyan liquid ejection unit 101C detects the detection result of “B position”. Is output.

  The detection unit 60A for the black liquid ejection unit 101K includes an imaging control unit 14A, an image storage unit 15A, and an imaging unit 16A. The detection unit 60B for the cyan liquid ejection unit 101C includes an imaging control unit 14B, an image storage unit 15B, and an imaging unit 16B. The function of each part of the detection unit 60A and the detection part 60B is the same, and the function of each part in the detection part 60A will be described below.

  The imaging unit 16A images the conveyed paper P. The imaging unit 16A is realized by the detection device 50, for example.

  The imaging control unit 14A includes a zoom control unit 141A and an image capturing unit 142A. Note that the imaging control unit 14A is realized by, for example, the control device 52 or the like. The zoom control unit 141A controls the optical zoom magnification that the imaging unit 16A images. The image capturing unit 142A acquires an image captured by the imaging unit 16A.

  The image storage unit 15A stores the image captured by the imaging control unit 14A. The image storage unit 15A is realized by the storage device 53, for example.

  Based on the images stored in the image storage units 15A and 15B, the calculation unit 61 calculates the pattern position of the paper P, the transport speed at which the paper P is transported, and the transport amount at which the paper P is transported. calculate. Further, the calculation unit 61 may calculate the exposure time, the optical zoom magnification, and the like in the imaging units 16A and 16B based on the calculated conveyance speed.

  Further, the calculation unit 61 outputs, for example, data of the time difference Δt indicating the shutter timing to the imaging control units 14A and 14B. That is, the calculation unit 61 transmits the shutter timing to the imaging control units 14A and 14B so that the image indicating the “A position” and the image indicating the “B position” are captured with the time difference Δt. The calculation unit 61 may control a motor or the like that transports the paper P so that the calculated transport speed is achieved. The calculation unit 61 is realized by, for example, the arithmetic device 54 or the like.

  The paper P has light scattering properties on the surface or inside. Therefore, when the paper P is irradiated with laser light, the irradiation light is diffusely reflected on the surface or inside. When the diffusely reflected light interferes, a pattern called a speckle pattern with spots is formed on the paper P. Therefore, when the paper P irradiated with the laser light is imaged, a speckle pattern appears in the captured image. The position of the paper P can be obtained based on the detection position of the speckle pattern appearing in the captured image.

  The speckle pattern appearing in the images captured by the imaging units 16A and 16B changes in position as the paper P is conveyed. Therefore, the calculation unit 61 can obtain the transport amount of the paper P based on the change in the position of the speckle pattern in the captured image taken at a predetermined time interval. Further, the calculation unit 61 can obtain the transport speed of the paper P by converting the transport amount per unit time.

  Specifically, assuming that the distance between the first imaging lens 12A and the second imaging lens 12B is a relative distance L [mm], the relationship between the relative distance L [mm] and the conveyance speed V [mm / s] is It can be shown as the following formula (1).

Δt = L / V (1)
In the above equation (1), the relative distance L [mm] is an interval between the first imaging lens 12A and the second imaging lens 12B, and is a preset value. Therefore, when the time difference Δt is determined, the calculation unit 53F can obtain the transport speed V [mm / s] based on the above equation (1). Thus, the transport amount and transport speed of the paper P can be obtained based on the speckle pattern appearing in the captured image.

  Further, the calculation unit 61 can obtain the displacement amount in the width direction from the initial position of the paper P by integrating the displacement amount in the width direction of the speckle pattern in the captured image. Further, the calculation unit 61 can obtain the current position in the width direction of the paper P based on the displacement amount.

  In addition, the calculation unit 61 performs a cross-correlation operation on the image data Dt1 (n) and Dt2 (n) indicating the images captured by the detection units 60A and 60B. Hereinafter, an image generated by the cross correlation calculation is referred to as a “correlation image”. For example, the calculation unit 61 calculates the shift amount ΔD (n) based on the correlation image.

  For example, the cross correlation calculation is expressed by the following equation (2).

Dt1 * Dt2 * = F-1 [F [Dt1] · F [Dt2] *] (2)
In the above equation (2), “Dt1” is image data Dt1 (n) indicating an image captured at “A position”. “Dt2” is image data Dt2 (n) indicating an image captured at “B position”. “F []” represents a Fourier transform, and “F-1 []” represents an inverse Fourier transform. “*” Represents a complex conjugate, and “★” represents a mutual intubation calculation.

  As shown in the above equation (2), when cross-correlation calculation “Dt1 * Dt2” is performed on the image data Dt1 and Dt2, image data indicating a correlation image is obtained. When the image data Dt1 and Dt2 are two-dimensional image data, the image data indicating the correlation image is two-dimensional image data. If the image data Dt1 and Dt2 are one-dimensional image data, the image data indicating the correlation image is one-dimensional image data.

  In the correlation image, for example, when a broad luminance distribution becomes a problem, the phase only correlation method may be used. The phase only correlation method is, for example, a method using the following equation (3).

Dt1 * Dt2 * = F-1 [P [F [Dt1]] · P [F [Dt2] *]] (3)
In the above equation (3), “P []” represents that only the phase is extracted from the complex amplitude. The amplitudes are all “1”. By using the above equation (3), the calculation unit 61 can calculate the shift amount ΔD (n) based on the correlation image even with a broad luminance distribution.

  The correlation image indicates the correlation between the image data Dt1 and Dt2. Specifically, as the degree of coincidence between the image data Dt1 and Dt2 is higher, a steeper peak, that is, a so-called correlation peak is output at a position closer to the center of the correlation image. When the image data Dt1 and Dt2 match, the center and peak position of the correlation image overlap.

  Based on the timing calculated as described above, the black liquid discharge unit 101K and the cyan liquid discharge unit 101C each discharge liquid. The liquid discharge timing is controlled by the first signal SIG1 for the black liquid discharge unit 101K and the second signal SIG2 for the cyan liquid discharge unit 101C output from the control unit 62. As shown in the figure, based on the result of calculation by the calculation unit 61, the control unit 62 outputs a signal to control the timing. The control unit 62 is realized by the control device 52 or the like, for example.

  Further, the calculation unit 61 may output the determined transport speed V to the setting unit 63. For example, the setting unit 63 calculates an optical zoom magnification, an aperture value, an exposure time, or the like based on the conveyance speed V received from the calculation unit 61. In addition, the conveyance speed V may be input to the setting unit 63 based on an operation mode such as the resolution of the output image. The setting unit 63 is realized by a setting device 521 such as a microcomputer, for example.

  For example, the setting unit 63 sets the optical zoom magnification to be lowered when the transport speed V is high. The zoom control units 141A and 141B operate the actuators ACA and ACB to control the zoom lens ZM so that the optical zoom magnification set by the setting unit 63 is obtained. The setting unit 63 may set an aperture value, a shutter speed, and the like.

  For example, the setting unit 63 obtains the aperture value by the following expression (4) so that the received light amount is inversely proportional to the exposure time determined by the conveyance speed V.

I = Io × (NA × Mo) ²
Depth of focus = ± k × wavelength / {2 × (numerical aperture) ² } (4)
In the above equation (4), “I” is the brightness of the image, and “Io” is the brightness of the sample surface. “NA” is a numerical aperture that is an example of an aperture value. “Mo” is the magnification of the objective lens. In the case of the above equation (4), the amount of received light is proportional to the square of the numerical aperture, so when the exposure time is set to “½” times, the numerical aperture is set to “√2” times. The Note that the optical zoom magnification, the exposure time, and the aperture value corresponding to the conveyance speed may be set in advance based on experiments or evaluations.

  Further, the optical zoom magnification is obtained as follows, for example. First, the shutter speed is set corresponding to the conveyance speed V. Specifically, when the transport speed V is high, the object to be transported moves at a high speed, so the shutter speed is often increased. Therefore, the shutter speed is set to be proportional to the conveyance speed V.

  When the shutter speed is set to a high speed, the amount of received light decreases. That is, when the shutter speed is set in accordance with the conveyance speed V, the amount of received light is in inverse proportion to the conveyance speed V. Therefore, when the transport speed V is set to a high speed, the optical zoom magnification is set to be lowered. When the optical zoom magnification is lowered, the amount of blurring for one pixel can be reduced.

  For example, the optical zoom magnification can be obtained as follows. Hereinafter, as a specific example, a case where the conveyance speed V is changed from “1 m / s” to “3 m / s” to increase the speed three times will be described. Further, it is assumed that the area to be imaged is a uniform illumination condition and a lens having the same aperture.

  First, the shutter speed is set to be tripled as the conveyance speed V is tripled. When the shutter speed is tripled, the amount of received light becomes 1/3 times darker. On the other hand, if the openings are the same, the amount of light received is determined by the light receiving area. The amount of received light is inversely proportional to the square of the optical zoom magnification. Therefore, in order to triple the amount of received light, the optical zoom magnification is obtained based on the following equation (5).

Shutter speed 3 times ... Received light amount 1/3
Received light quantity 3 times = 1 / (1 / √3) 2 = 3 times ... Optical zoom magnification 1 / √3 ≒ 0.57 times (5)
As described above, when the optical zoom magnification is lowered in accordance with the conveyance speed V, the amount of received light can be maintained or increased. Further, the relative blur amount can be reduced by lowering the optical zoom magnification.

  FIG. 15 is an external view illustrating a sensor 200 in the embodiment. The sensor 200 includes a semiconductor laser light source (LD) and a collimating optical system (CL) that generate a speckle pattern by irradiating an object such as paper P with a laser beam. The sensor 200 includes a CMOS image sensor that images a speckle pattern, and a telecentric imaging optical system (OL) that focuses and images the speckle pattern on the CMOS image sensor. The sensor 200 may be provided with a light emitting diode (LED) as a light source.

  For example, the CMOS image sensor captures an image including a speckle pattern at a predetermined cycle. In the FPGA circuit, a cross-correlation calculation is performed using the captured image at time T1 and the captured image at time T2, and the movement amount of the object from time T1 to time T2 is output based on the movement of the correlation peak position.

  The sensor 200 illustrated in FIG. 15 has, for example, a width W of 15 mm, a depth D of 60 mm, and a height H of 32 mm. The CMOS image sensor is an example of an imaging unit, and the FPGA circuit is an example of an arithmetic device.

  The above-described sensor 200 is preferably provided in the vicinity of the discharge position of the liquid discharge unit 101. By detecting the position of the paper P in the vicinity of the discharge position, the position in the width direction of the liquid discharge unit 101 can be accurately controlled according to the position of the paper P.

  FIG. 16 is a diagram illustrating the arrangement of the sensors 200 in the embodiment. FIG. 16 is a side view including the liquid discharge unit 101 and the sensor 200.

  As shown in FIG. 16, on the upstream side and downstream side of the liquid discharge position PT of the liquid discharge unit 101, the paper P is supported from the lower surface side (the side opposite to the surface from which liquid is discharged from the liquid discharge unit 101). A first roller CR1 and a second roller CR2 are provided. The first roller CR <b> 1 and the second roller CR <b> 2 are rotatably provided, and rotate following the paper P. As long as the paper P can be supported on the upstream side and the downstream side of the liquid discharge position PT of the liquid discharge unit 101, for example, a fixing member that is in sliding contact with the paper P may be used, and the first roller CR1 and the second roller CR2 may be used. As described above, the roller may not be a roller that rotates following the paper P.

  In the configuration illustrated in FIG. 16, the sensor 200 is provided on the opposite side of the paper P from the liquid discharge unit 101, so that the detection position is between the first roller CR <b> 1 and the liquid discharge position PT. .

  The sensor 200 is preferably provided so that the detection position is between the first roller CR1 and the second roller CR2. Between the first roller CR1 and the second roller CR2, the transport position of the paper P is stable and the distance from the sensor 200 is kept constant, so that the position of the paper P can be detected with high accuracy. .

  The sensor 200 is preferably provided such that the detection position is upstream of the discharge position PT of the liquid discharge unit 101 and the detection position is in the vicinity of the discharge position PT. By providing the sensor 200 so that the detection position is on the upstream side of the discharge position PT, the discharge position PT of the liquid discharge unit 101 can be accurately aligned with the position of the paper P using the detection result of the sensor 200. . Further, by reducing the interval between the detection position of the sensor 200 and the discharge position PT, the influence of the deviation of the transport position of the paper P between the detection position and the discharge position PT is minimized, and the liquid discharge unit 101 The position can be adjusted to the position of the paper P.

  The position correction device, the liquid ejection device, and the position correction method according to the embodiments have been described above. However, the present invention is not limited to the above embodiments, and various modifications and improvements can be made within the scope of the present invention. It is.

DESCRIPTION OF SYMBOLS 10 Liquid discharge system 100 Liquid discharge apparatus 101 Liquid discharge unit 102 Edge sensor 103 Actuator (unit moving part)
110 Liquid Discharge Head 111 First Liquid Discharge Head 112, 114 Nozzle (Liquid Discharge Unit)
113 Second liquid ejection head 150 Position correction device 161 Position detection unit 162 Movement amount determination unit 163 Conveyance speed detection unit 164 Movement speed determination unit 165 Movement control unit P Paper (conveyed object)

JP 2010-137489 A

Claims (9)

A position correction device that corrects the position of a liquid discharge unit that discharges liquid to a transferred object,
A position detector for detecting a position in the width direction of the conveyed object;
A unit moving section for moving the liquid discharge unit in the width direction;
A movement amount determination unit that determines a movement amount of the liquid ejection unit in the width direction based on a position in the width direction of the conveyed object;
A moving speed determining unit that determines a moving speed of the liquid discharge unit according to a transport speed of the object to be transported;
And a movement control unit that controls the unit moving unit so as to move the liquid discharge unit in the width direction at the moving speed and the moving amount. The movement control unit controls the unit moving unit to move the liquid discharge unit every time the object to be conveyed is conveyed a predetermined control distance,
The movement speed determination unit determines the movement speed so that the liquid discharge unit moves a predetermined movement distance while the object to be conveyed is conveyed by the control distance. The position correction apparatus described. The position correction apparatus according to claim 2, wherein the movement speed determination unit determines the movement speed when a conveyance speed of the object to be conveyed becomes constant. A conveyance speed detection unit that detects a conveyance speed of the object to be conveyed based on a conveyance signal that is output every time the object to be conveyed is conveyed by a predetermined detection distance from a conveyance unit that conveys the object to be conveyed; ,
The said movement speed determination part determines the said movement speed based on the conveyance speed of the said to-be-conveyed object detected by the said conveyance speed detection part, It is any one of Claim 1 to 3 characterized by the above-mentioned. Position correction device. 5. The position correction apparatus according to claim 1, wherein the position detection unit detects an end position of the transported object in the width direction. 5. The position correction according to claim 1, wherein the position detection unit detects a position of the transported object in the width direction based on a pattern of the transported object. apparatus. The position correction device according to claim 6, wherein the position detection unit detects the pattern from a two-dimensional captured image of the transported object.   A liquid ejection apparatus comprising the position correction apparatus according to claim 1. A position correction method for correcting the position of a liquid discharge unit that discharges liquid to a transferred object,
A position detecting step for detecting a position in the width direction of the conveyed object;
A movement amount determining step for determining a movement amount of the liquid ejection unit in the width direction based on a position in the width direction of the conveyed object;
A moving speed determining step for determining a moving speed of the liquid discharge unit in accordance with a transport speed of the transported object;
And a movement control step of moving the liquid discharge unit in the width direction at the movement speed and the movement amount.

Images