Printer, control method for the same, and computer program

Abstract

To suppress generation of banding caused by cutting processing of a medium to be printed.SOLUTION: A printer controller performs: first printing processing which repeats for a few times a recording step including a first path action discharging ink from a nozzle into a first path area of a medium to be printed while moving a head in a moving direction from a moving device and first conveying operation conveying the medium to be printed just for a first conveyance quantity equal to or below a dimension of a nozzle range in a conveying direction with the conveying device, and overlaps a part of the first path area to be an object of the first path action of the current recording step on a part of the first path area to be an object of the first path action of the previous recording step; cutting processing that cuts the medium to be printed with a cutter; and correction processing that corrects a first conveyance quantity in the first printing processing so as to have a downstream end in the conveyance direction in the first path area during execution of the cutting processing face the downstream end in the conveyance direction in the nozzle range. The cutter cuts the medium to be printed after execution of the correction processing.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a printing apparatus, a control method thereof, and a computer program.

Background Art

[0002] As a conventional printing apparatus, for example, the image forming apparatus of Patent Document 1 is known. This image forming apparatus includes a cutter mechanism for cutting a roll paper, a roller for conveying the roll paper, and an image forming unit for forming an image on the roll paper.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] For example, when the image forming unit is a serial head, the image forming apparatus alternately executes a pass operation of discharging ink from the head while moving the head along a direction intersecting the conveyance direction of the roll paper, and a conveyance operation of conveying the roll paper along the conveyance direction. If the roll paper is cut by the cutter mechanism during this conveyance operation, the conveyance of the roll paper is interrupted due to the cutting operation, so the conveyance amount of the roll paper after the cutting operation becomes short, and the conveyance accuracy of the roll paper by the roller decreases. As a result, the images printed by the pass operation may be misaligned, and banding may occur.

[0005] In view of such a situation, an object of the present disclosure is to provide a printing apparatus, a control method thereof, and a computer program capable of suppressing the occurrence of banding caused by cutting processing of a long printing medium such as roll paper.

Means for Solving the Problems

[0006] A printing apparatus according to an aspect of the present disclosure includes a supply tray that supplies a printing medium, a head having a discharge surface including a nozzle range provided with a plurality of nozzles that discharge ink onto the printing medium, a moving device that moves the head in a moving direction, a conveying device that conveys the printing medium along a conveying direction intersecting the moving direction, a cutter that is disposed closer to the supply tray than the head and cuts the printing medium, and a control device. The control device includes a first pass operation of discharging ink from the nozzles to a first pass area of the printing medium while moving the head along the moving direction by the moving device, and a first conveyance operation of conveying the printing medium by a first conveyance amount equal to or less than the dimension of the nozzle range in the conveying direction by the conveying device. The control device repeatedly performs a plurality of recording steps including the first pass operation and the first conveyance operation, and performs a first printing process of overlapping a part of the first pass area targeted in the first pass operation of the current recording step with a part of the first pass area targeted in the first pass operation of the previous recording step, a cutting process of cutting the printing medium by the cutter, and a correction process of correcting the first conveyance amount in the first printing process so that the downstream end in the conveying direction in the first pass area faces the downstream end in the conveying direction in the nozzle range when the cutting process is executed. The cutter cuts the printing medium after the correction process is executed.

[0007] A control method for a printing apparatus according to an aspect of the present disclosure includes a supply tray for supplying a printing medium, a head having a discharge surface including a nozzle range provided with a plurality of nozzles for discharging ink onto the printing medium, a moving device for moving the head in a moving direction, a conveying device for conveying the printing medium along a conveying direction intersecting the moving direction, and a cutter disposed closer to the supply tray than the head for cutting the printing medium. The control method for the printing apparatus includes a first pass operation of discharging ink from the nozzles to a first pass area of the printing medium while moving the head along the moving direction by the moving device, and a first conveyance operation of conveying the printing medium by a first conveyance amount equal to or less than the dimension of the nozzle range in the conveying direction by the conveying device. A recording process including the above is repeated a plurality of times. A first printing process of overlapping a part of the first pass area targeted by the first pass operation of the current recording process with a part of the first pass area targeted by the first pass operation of the previous recording process, a cutting process of cutting the printing medium by the cutter, and a correction process of correcting the first conveyance amount in the first printing process so that a downstream end in the conveying direction in the first pass area faces a downstream end in the conveying direction in the nozzle range when the cutting process is executed are performed. The cutter cuts the printing medium after the execution of the correction process.

[0008] A computer program according to an aspect of the present disclosure is for a computer of a printing apparatus including a supply tray that supplies a printing medium, a head having a discharge surface including a nozzle range provided with a plurality of nozzles that discharge ink onto the printing medium, a moving device that moves the head in a moving direction, a conveyance device that conveys the printing medium along a conveyance direction intersecting the moving direction, and a cutter that is disposed closer to the supply tray than the head and cuts the printing medium. The computer causes the moving device to move the head along the moving direction while discharging ink from the nozzles onto a first pass area of the printing medium in a first pass operation, and causes the conveyance device to convey the printing medium by a first conveyance amount that is equal to or less than the dimension of the nozzle range in the conveyance direction in a first conveyance operation. The computer repeatedly executes a plurality of recording steps including the first pass operation and the first conveyance operation, and executes a first printing process in which a part of the first pass area targeted in the first pass operation of the current recording step overlaps a part of the first pass area targeted in the first pass operation of the previous recording step, a cutting process in which the cutter cuts the printing medium, and a correction process in which the first conveyance amount in the first printing process is corrected so that a downstream end in the conveyance direction in the first pass area faces a downstream end in the conveyance direction in the nozzle range when the cutting process is executed. The computer causes the cutter to cut the printing medium after the correction process is executed.

Advantages of the Invention

[0009] In a printing apparatus, while the downstream end of the nozzle area faces the downstream end of the first pass area, the printing medium is not conveyed. By executing the cutting process while the printing medium is stopped, the conveyance operation of the printing medium is not interrupted for the cutting process. Therefore, the conveyance amount of the printing medium does not become shorter than the first conveyance amount due to the interruption of the conveyance operation, and a decrease in the conveyance accuracy of the printing medium is suppressed. As a result, the occurrence of banding due to the cutting process of a long printing medium such as roll paper can be suppressed.

[0010] The above object, other objects, features, and advantages of the present disclosure will become apparent from the following detailed description of the preferred embodiments with reference to the accompanying drawings.

Brief Description of the Drawings

[0011]

Figure 1

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Embodiments for Carrying Out the Invention

[0012] (First Embodiment) <Printing Apparatus> As shown in FIG. 1, the printing apparatus 10 according to the first embodiment of the present disclosure is, for example, an inkjet printer of a serial head type in which the head 20 discharges ink while moving in the moving direction onto the printing medium A. The printing medium A is a long sheet-like medium and is pulled out from a roll body Ar wound in a roll shape. As the sheet-like medium, for example, paper, cloth, labels, and the like are used.

[0013] Note that the moving direction of the head 20 is referred to as the left-right direction, and the conveyance direction in which the printing medium A is conveyed at a position that intersects (for example, is orthogonal to) the moving direction and faces the head 20 is referred to as the front-rear direction. Also, the direction that intersects (for example, is orthogonal to) the moving direction and the conveyance direction is referred to as the up-down direction. However, the directions related to the printing apparatus 10 are not limited to this.

[0014] The printing apparatus 10 includes a head 20 and a platen 11. The head 20 has a plurality of nozzles 21 (FIG. 3), a discharge surface 22 through which the nozzles 21 open, and a plurality of drive elements 23 (FIG. 2). The drive elements 23 are, for example, piezoelectric elements, resistive heaters, electrostatic actuators, etc., and are provided for each nozzle 21 to apply a discharge pressure to the ink in the head 20 to the ink. The platen 11 is disposed below the head 20, has an upper surface facing the discharge surface 22 which is the lower surface of the head 20, and supports the printing medium A disposed on the upper surface from below. Details of the head 20 will be described later.

[0015] Furthermore, the printing apparatus 10 includes a moving device 30 that moves the head 20 in the left - right direction. The moving device 30 has a carriage 31, a rail 32, and a moving motor 33 (FIG. 2). The rail 32 extends in the left - right direction. The carriage 31 mounts the head 20 and is supported by the rail 32 so as to be movable in the left - right direction along the rail 32. By driving the moving motor 33, the carriage 31 and the head 20 move in the left - right direction on the platen 11.

[0016] Furthermore, the printing apparatus 10 includes a housing 12 that houses the head 20, a supply tray 13, and a discharge tray 14. The housing 12 has, for example, a rectangular parallelepiped shape, and a lower opening 12a and an upper opening 12b disposed above the lower opening 12a are provided in its front wall, and it has an internal space. The head 20 is disposed in the internal space of the housing 12. The supply tray 13 is a tray that supplies the printing medium A to the head 20, and a columnar roll body Ar is accommodated so that its central axis extends in the left - right direction. The supply tray 13 is disposed below the head 20 in the internal space of the housing 12 so as to be insertable into and removable from the housing 12 through the lower opening 12a of the housing 12. The discharge tray 14 is provided at the upper opening 12b of the housing 12 above the supply tray 13, and the printing medium A printed by the head 20 is discharged from the housing 12.

[0017] Furthermore, the printing apparatus 10 includes a conveyance device 40 that conveys the printing medium A along the conveyance direction. The conveyance device 40 has a supply roller 41, a pair of guide rollers 42, a pair of upstream rollers 43, a pair of downstream rollers 44, and a conveyance motor 45 (FIG. 2). Each of these rollers has a rotation axis extending in the left-right direction.

[0018] One of the supply roller 41, one of the pair of guide rollers 42, one of the pair of upstream rollers 43, and one of the pair of downstream rollers 44 is a drive roller that rotates about the rotation axis by the drive of the conveyance motor 45. The other of the pair of guide rollers 42, the other of the pair of upstream rollers 43, and the other of the pair of downstream rollers 44 are driven rollers that rotate as the drive roller rotates. Note that the supply roller 41, the guide rollers 42, the upstream rollers 43, and the downstream rollers 44 may be connected to the same conveyance motor 45 as each other, or may be connected to different conveyance motors 45 from each other.

[0019] The supply roller 41 is disposed on the supply tray 13 and feeds out the printing medium A drawn from the roll body Ar rearward. The guide rollers 42 are disposed between the supply roller 41 and the head 20 in the vertical direction and are disposed rearward of the supply roller 41 and the head 20 in the front-rear direction. The pair of guide rollers 42 sandwich the printing medium A fed out by the supply roller 41 therebetween and convey it upward.

[0020] The upstream rollers 43 are disposed above the guide rollers 42 in the vertical direction and are disposed forward of the guide rollers 42 in the front-rear direction. The pair of upstream rollers 43 are arranged vertically and sandwich the printing medium A conveyed by the guide rollers 42 therebetween and convey it forward. The downstream rollers 44 are disposed forward of the upstream rollers 43. The pair of downstream rollers 44 are arranged vertically and sandwich the printing medium A conveyed by the upstream rollers 43 therebetween and convey it forward.

[0021] In the front-rear direction, a platen 11 is disposed between an upstream roller 43 and a downstream roller 44, and a discharge tray 14 is disposed in front of the downstream roller 44. Therefore, in the conveyance direction of the print medium A conveyed on the platen 11, the upstream roller 43 is disposed upstream of the platen 11, and the downstream roller 44 is disposed downstream of the platen 11. Then, the print medium A is nipped by a pair of upstream rollers 43 and conveyed onto the platen 11. Ink is ejected from the head 20 on the platen 11 to print an image, and the print medium A is nipped by a pair of downstream rollers 44 and conveyed to the discharge tray 14. Thus, the conveyance path 47 of the print medium A is defined by a supply tray 13, supply rollers 41, guide rollers 42, upstream roller 43, platen 11, downstream roller 44, and discharge tray 14.

[0022] Furthermore, the conveyance device 40 includes an encoder 46 (FIG. 2) and a conveyance sensor 48. The encoder 46 detects the rotation angle and rotation direction of the conveyance motor 45 and outputs a detection signal thereof. The conveyance sensor 48 is a sensor for detecting the presence or absence of the print medium A, and a known sensor such as an optical sensor can be used. The conveyance sensor 48 is disposed upstream of the head 20 in the conveyance path 47, that is, closer to the supply tray 13 than the head 20 in the conveyance path 47. In the example of FIG. 1, the conveyance sensor 48 is disposed between the guide roller 42 and the supply tray 13 in the conveyance path 47. When the conveyance sensor 48 detects the print medium A being conveyed along the conveyance path 47, it outputs a detection signal. Based on the detection signals of the encoder 46 and the conveyance sensor 48, the position of the print medium A is acquired.

[0023] Furthermore, the printing device 10 includes a cutting device 50 for cutting the print medium A. The cutting device 50 includes a cutter 51 and a cutting motor 52 (FIG. 2) for controlling the cutter 51. The cutter 51 is upstream of the head 20 in the conveyance path 47 of the print medium A, that is, closer to the supply tray 13 than the head 20, and is disposed, for example, between the conveyance sensor 48 and the supply tray 13.

[0024] The cutter 51 is, for example, a pair of rotary blades that rotate about its rotation axis. Driven by the cutting motor 52, the cutter 51 moves in the left - right direction while rotating to cut the printed medium A. As a result, as shown in FIG. 3, in the transport direction of the printed medium A, the end A2, which is the upstream end, is formed in the printed medium A (the printed medium to be printed this time) downstream of the cutting position A3, and the tip A1, which is the downstream end, is formed in the printed medium A (the printed medium to be printed next time) upstream of the cutting position A3.

[0025] Furthermore, as shown in FIG. 2, the printing apparatus 10 includes a control device 60 that controls its components, and a communication interface 63, a head drive circuit 64, a transport drive circuit 65, a movement drive circuit 66, and a cutting drive circuit 67 that are electrically connected to the control device 60. The control device 60 is connected to the transport sensor 48 and the encoder 46. Note that the control device 60 may be constituted by a single device, or a plurality of devices may be distributed and configured such that they cooperate to perform the operations of the control device 60.

[0026] The control device 60 is constituted by, for example, a computer and has an arithmetic processing unit 61 and a storage unit 62. The arithmetic processing unit 61 includes circuits such as a processor like a CPU, an integrated circuit like an ASIC, or a combination thereof. The storage unit 62 is a memory accessible from the arithmetic processing unit 61 and has, for example, a RAM and a ROM. The storage unit 62 stores various data such as print jobs, as well as computer programs and data for performing various data processes.

[0027] A print job includes image data and printing conditions. The image data is data representing an image, for example, raster data composed of a plurality of pixels obtained by dividing the image. The printing conditions include, for example, the dimension a1 of the margin in the front-back direction (FIG. 3), the resolution of the image to be printed, and the number of singlings, etc. The arithmetic processing unit 61 controls the operations of each part of the printing apparatus 10 by executing a computer program while referring to the data stored in the storage unit 62. Note that singling will be described later. Also, the printing conditions may be predetermined.

[0028] The communication interface 63 is a connecting device that connects the control device 60 to external devices of the printing apparatus 10. Examples of external devices include other computers, mobile terminals, cameras, external servers, recording media, etc. The communication interface 63 may be connected to an external device by wired communication such as a USB cable or wireless communication such as a LAN. The control device 60 acquires various data such as a print job from an external device via this communication interface 63 and stores it in the storage unit 62.

[0029] The head drive circuit 64 is electrically connected to the drive element 23 of the head 20. The control device 60 generates a control signal for controlling the drive of the drive element 23 based on the print job, and the head drive circuit 64 generates a drive signal based on the input control signal. As a result, the drive element 23 is driven based on the drive signal, and a discharge pressure is applied to the ink in the head 20. Thereby, the ink discharge timing and the size of the discharged ink droplets (ink droplet volume) are controlled by the control device 60 based on the print job.

[0030] The movement drive circuit 66 is electrically connected to the movement motor 33 of the moving device 30. The control device 60 generates a control signal for controlling the drive of the movement motor 33 based on the print job, and the movement drive circuit 66 generates a drive signal based on the input control signal. As a result, the movement motor 33 is driven based on the drive signal, and the moving device 30 can move the head 20 in the left - right direction and stop the head 20 at any position within its movable range.

[0031] The conveyance drive circuit 65 is electrically connected to the conveyance motor 45 of the conveyance device 40. The control device 60 generates a control signal for controlling the drive of the conveyance motor 45 based on the print job based on the detection signals of the conveyance sensor 48 and the encoder 46, and the conveyance drive circuit 65 generates a drive signal based on the input control signal. As a result, the conveyance motor 45 is driven based on the drive signal, and the conveyance device 40 can intermittently or continuously convey the print medium A from the supply tray 13 through below the head 20 to the discharge tray 14.

[0032] The cutting drive circuit 67 is electrically connected to the cutting motor 52 of the cutting device 50. The control device 60 generates a control signal for controlling the drive of the cutting motor 52 based on the print job, and the cutting drive circuit 67 generates a drive signal based on the input control signal. As a result, the cutting motor 52 is driven based on the drive signal, and the cutting device 50 cuts the print medium A with the cutter 51.

[0033] <Head> As shown in FIG. 3, on the ejection surface 22 of the head 20, a plurality (in the example of FIG. 3, four) of nozzle rows are arranged in the left - right direction. In each nozzle row, a plurality of nozzles 21 are arranged in a row in the front - rear direction at a predetermined pitch b. This pitch b is the dimension of the interval between the centers of two adjacent nozzles 21 along the front - rear direction on the ejection surface 22. Also, on the ejection surface 22, a nozzle range 24 where the nozzles 21 are arranged is provided. In the front - rear direction, the dimension e of this nozzle range 24 is equal to the dimension of the nozzle row.

[0034] <Position alignment process> The printing apparatus 10 executes a position alignment process for aligning the positions of the head 20 and the printing area C in order to print an image on the printing area C of the print medium A by the head 20. In this position alignment process, the control device 60 detects the leading edge A1 of the print medium A being conveyed along the conveyance path 47 based on the detection signals of the conveyance sensor 48 and the encoder 46 of the conveyance motor 45. Then, the control device 60 acquires, as the downstream end C1 of the printing area C, the position obtained by adding the margin dimension a1 to this leading edge A1.

[0035] Then, the control device 60 conveys the print medium A forward so that the upstream end 24f of the nozzle range 24 on the ejection surface 22 of the head 20 faces the downstream end C1. As a result, in the example of FIG. 3, the nozzle range 24 is arranged at the position p0 with respect to the print medium A. In FIG. 3, the position of the nozzle range 24 with respect to the print medium A along the front-rear direction is schematically represented by a rectangle.

[0036] <First printing process> Thus, after the position alignment process between the nozzle range 24 of the head 20 and the printing area C of the print medium A is performed, a first printing process for printing an image on the printing area C with the ink ejected from the nozzles 21 of the nozzle range 24 is executed. In this first printing process, the control device 60 repeats a plurality of recording steps. This recording step includes a first pass operation and a first conveyance operation, and the first pass operation and the first conveyance operation are alternately executed in a plurality of recording steps.

[0037] In addition, in FIG. 3, when the nozzle range 24 is arranged at each of the positions p1~ with respect to the print medium A, the first pass operation is executed. The rectangle indicating this nozzle range 24 has a white range and a shaded range. This white range is an ink ejection range for ejecting ink in the first pass operation, and the shaded range is an ink non-ejection range for not ejecting ink in the first pass operation.

[0038] In the first pass operation, the control device 60 ejects ink from the nozzles 21 of the head 20 onto the first pass area Fa of the print medium A while moving the head 20 to the right or left. As a result, dots are formed in the first pass area Fa, and a first pass image composed of the dots is formed. This first pass area Fa is a partial area of the print medium A and is the area of the print medium A that faces the nozzle range 24 of the head 20 in the first pass operation, and is an area where ink can be ejected from the nozzles 21 of the nozzle range 24 by one first pass operation. For example, the first pass area Fa targeted in the first first pass operation is the area F1, and the first pass area Fa targeted in the second first pass operation is the area F2. The dimension of the first pass area Fa in the front-rear direction is equal to the dimension e of the nozzle range 24.

[0039] Then, in the first conveyance operation, the control device 60 conveys the print medium A forward by a first conveyance amount d1 with respect to the head 20. As a result, the current first pass area Fa is shifted rearward by the first conveyance amount d1 from the first pass area Fa of the previous first pass operation executed immediately before the current first pass operation. In the example of FIG. 3, the first pass area Fa is the area F1 in the first first pass operation, the area F2 shifted rearward by the first conveyance amount d1 from the area F1 in the second first pass operation, the area F3 shifted rearward by the first conveyance amount d1 from the area F2 in the third first pass operation, and the area F4 shifted rearward by the first conveyance amount d1 from the area F3 in the fourth first pass operation.

[0040] With such a shift of the first pass area Fa, the first pass image formed in the first pass area Fa by the current first pass operation is shifted rearward by the first conveyance amount d1 from the first pass image formed in the first pass area Fa by the previous first pass operation. In this way, a plurality of first pass images are formed while being shifted rearward by the first printing process, and the image composed of these is printed on the print medium A.

[0041] The first conveyance amount d1 is equal to or less than the dimension e of the nozzle range 24 of the head 20 in the front-rear direction, and is shorter than the dimension e when the first printing process is executed in a multi-pass method. According to the first printing process in the multi-pass method, a part of the first pass area Fa targeted by the current first pass operation overlaps with a part of the first pass area Fa targeted by the previous first pass operation.

[0042] The first conveyance amount d1 is determined by, for example, the resolution of the head 20, the resolution of the image, and the singling number. In the example of FIG. 3, the resolution of the head 20 is 300 dpi, the resolution of the image is 600 dpi, and the singling number is 2. In this case, the first conveyance amount d1 is the sum (e / 4 + b / 2) of one-fourth of the dimension e of the nozzle range 24 and one-half of the pitch b of the nozzles 21.

[0043] <Multi-pass method> The pass period of the multi-pass method is the image resolution / the resolution of the head 20 × the singling number. The pass period in the example of FIG. 3 is 600 / 300 × 2 = 4. Therefore, the printed area C is overlaid with the first pass images by the first pass operations of 4 cycles. In bidirectional printing, in the first pass operations of the first cycle and the third cycle, the head 20 moves to one of the right and left while discharging ink from the nozzles 21, and in the first pass operations of the second cycle and the fourth cycle, the head 20 moves to the other of the right and left while discharging ink from the nozzles 21.

[0044] In the first printing process, a plurality of first pass operations are performed. Among these, the (4n - 3)-th (n is a natural number) first pass operation is the first cycle, the (4n - 2)-th first pass operation is the second cycle, the (4n - 1)-th first pass operation is the third cycle, and the 4n-th first pass operation is the fourth cycle.

[0045] In accordance with this four-cycle first-pass operation, the nozzle range 24 has a first range 24a, a second range 24b, a third range 24c, and a fourth range 24d arranged in the front-rear direction, and the printing area C has a plurality of partial areas c1~ arranged in the front-rear direction. In each of the plurality of partial areas c1~, there are a first-pass image formed by the ink ejected from the nozzles 21 of the first range 24a by the first-pass operation of the first cycle, a first-pass image formed by the ink ejected from the nozzles 21 of the second range 24b by the first-pass operation of the second cycle, a first-pass image formed by the ink ejected from the nozzles 21 of the third range 24c by the first-pass operation of the third cycle, and a first-pass image formed by the ink ejected from the nozzles 21 of the fourth range 24d by the first-pass operation of the fourth cycle, which are laminated.

[0046] Specifically, as shown in FIG. 4 which is an enlarged view of a part of FIG. 3, the nozzle range 24 of the head 20 is arranged at the position p0 with respect to the printing medium A by the alignment process. Then, by the first conveyance operation of the first printing process, the printing medium A is conveyed forward by the first conveyance amount d1, and the nozzle range 24 is arranged at the position p1 with respect to the printing medium A. At this position p1, by the first-pass operation of the first time (the first cycle), ink is not ejected from the nozzles 21 of the second range 24b to the fourth range 24d, and ink is ejected from the nozzles 21 of the first range 24a. Thereby, a first-pass image is formed in the partial area c1 facing the first range 24a of the printing area C.

[0047] Subsequently, by the first conveyance operation, the printing medium A is conveyed forward by the first conveyance amount d1, and the nozzle range 24 is arranged at the position p2 with respect to the printing medium A. At this position p2, by the first-pass operation of the second time (the second cycle), ink is not ejected from the nozzles 21 of the third range 24c to the fourth range 24d, and ink is ejected from the nozzles 21 of the first range 24a to the second range 24b. Thereby, a first-pass image is formed in the partial areas c1 and c2 facing the first range 24a to the second range 24b of the printing area C. For this reason, the first-pass images by the first-pass operations of the first cycle to the second cycle are laminated in the partial area c1.

[0048] Subsequently, by the first conveyance operation, the printing medium A is conveyed forward by a first conveyance amount d1, and in the front-rear direction, the nozzle range 24 is disposed at a position p3 with respect to the printing medium A. At this position p3, by the third (third cycle) first pass operation, ink is not ejected from the nozzles 21 in the fourth range 24d, but ink is ejected from the nozzles 21 in the first range 24a to the third range 24c. As a result, a first pass image is formed in the partial regions c1 to c3 of the printing region C that face the first range 24a to the third range 24c. For this reason, the first pass images by the first pass operations in the first to third cycles are stacked in the partial region c1, and the first pass images by the first pass operations in the second to third cycles are stacked in the partial region c2.

[0049] Subsequently, by the first conveyance operation, the printing medium A is conveyed forward by a first conveyance amount d1, and the nozzle range 24 is disposed at a position p4 with respect to the printing medium A. At this position p4, by the fourth (fourth cycle) first pass operation, ink is ejected from the nozzles 21 in the first range 24a to the fourth range 24d. As a result, a first pass image is formed in the partial regions c1 to c4 of the printing region C that face the first range 24a to the fourth range 24d. For this reason, the first pass images by the first pass operations in the first to fourth cycles are stacked in the partial region c1, the first pass images by the first pass operations in the second to fourth cycles are stacked in the partial region c2, and the first pass images by the first pass operations in the third to fourth cycles are stacked in the partial region c3.

[0050] <Singling> When a plurality of first pass images are superimposed by the first printing process in this way, singling is performed to disperse the dots constituting the first pass image in the left-right direction. In the example of FIG. 3, the first pass operation in the first cycle and the first pass operation in the third cycle are taken as one set, the first pass operation in the second cycle and the first pass operation in the fourth cycle are taken as one set, and singling is performed for each set.

[0051] According to FIG. 5(a) showing the position of the nozzle range 24 with respect to the printing area C in FIG. 3, the first pass operation in the first cycle is executed when the nozzle range 24 is located at positions p(4n - 3) (n is a natural number), for example, p1, p5, p9, p13, p17. The first pass operation in the second cycle is executed when the nozzle range 24 is located at positions p(4n - 2), for example, p2, p6, p10, p14, p18. The first pass operation in the third cycle is executed when the nozzle range 24 is located at positions p(4n - 1), for example, p3, p7, p11, p15, p19. The first pass operation in the fourth cycle is executed when the nozzle range 24 is located at positions p(4n), for example, p4, p8, p12, p16, p20.

[0052] FIG. 5(b) shows the dot formation rate by the first pass operation in the first cycle, FIG. 5(c) shows the dot formation rate by the first pass operation in the second cycle, FIG. 5(d) shows the dot formation rate by the first pass operation in the third cycle, and FIG. 5(e) shows the dot formation rate by the first pass operation in the fourth cycle. One axis of the graph corresponding to the front-rear direction in FIG. 5(a) indicates the position in the printing area C along the front-rear direction, and the other axis perpendicular to one axis of the graph indicates the dot formation rate (%).

[0053] The dot formation rate (%) is (the number of dots s that can be formed side by side in the left-right direction by the first pass operation in each cycle) / (the number of dots t that can be formed side by side in the left-right direction by one set of the first pass operations)×100. In singling, the control device 60 disperses the dots formed by the first pass operation in the cycles that make up the set in the left-right direction. For this reason, the number of dots t is the number of dots that can be formed by the first pass operations in the first and third cycles that make up the set. The sum of the dot formation rate by the first pass operation in the first cycle and the dot formation rate by the first pass operation in the third cycle is 100%. Also, the number of dots t is the number of dots that can be formed by the first pass operations in the second and fourth cycles that make up the set. The dot formation rate by the first pass operation in the second cycle and the dot formation rate by the first pass operation in the fourth cycle are 100%.

[0054] In FIGS. 5(b) to 5(e), by gradation singling, the dot formation rate in one first pass operation has a gradient that changes from 0 to 100 (%). For example, the formation rate rises at a constant rate from 0 (%) to 100 (%) from the downstream end 24e of the nozzle range 24 to the middle 24g in the front-rear direction, and decreases at a constant rate from 100 (%) to 0 (%) from the middle 24g of the nozzle range 24 to the upstream end 24f. In this way, in the front-rear direction, regardless of the position of the nozzle range 24 with respect to the printing area C, the dot formation rate is set according to the position of the nozzle 21 in the nozzle range 24. Therefore, unevenness in image quality is reduced over the entire printing area C.

[0055] Here, the dotted lines in each graph indicate the formation rate corresponding to the ink non-ejection range (masking range) in the nozzle range 24, and the solid lines indicate the formation rate corresponding to the ink ejection range (white range) in the nozzle range 24. In the first pass operation for printing the end of the printing area C (the first first pass operation at position p1, the second first pass operation at position p2, and the third first pass operation at position p3), the nozzle range 24 has an ink non-ejection range and an ink ejection range. For the nozzle range 24 of such a first pass operation as well, a dot formation rate similar to that of the nozzle range 24 of other first pass operations is set. Therefore, dots are formed at a formation rate similar to that of other parts even at the end of the printing area C, so that unevenness in image quality is reduced over the entire printing area C.

[0056] As shown in FIGS. 6 to 9, dots are formed for each pixel area Cg in the printing area C by the first pass operation. Dots are formed in the pixel area Cg indicated by "1" in FIG. 6 by the first pass operation in the first cycle, and dots are formed in the pixel area Cg indicated by "3" in FIG. 8 by the first pass operation in the third cycle. Since the pixel area Cg "3" is arranged between adjacent pixel areas Cg "1" in the left-right direction, the dots are dispersed in the left-right direction by the first pass operations in the first cycle and the third cycle.

[0057] In the pixel region Cg indicating "2" in FIG. 7, dots are formed by the first pass operation in the second cycle, and in the pixel region Cg indicating "4" in FIG. 9, dots are formed by the first pass operation in the fourth cycle. Since the pixel region Cg "4" is arranged between the adjacent pixel regions Cg "2" in the left-right direction, the dots are dispersed in the left-right direction by the first pass operations in the second and fourth cycles.

[0058] <Interlace> For the first printing process in which the resolution of the image in the front-rear direction is larger than the resolution of the head 20, an interlace for forming dots by the current first pass operation at the interval between the dots formed by the previous first pass operation in the front-rear direction is used.

[0059] As shown in FIG. 9, the pixel regions Cg "1" and the pixel region Cg "3" are arranged side by side in the left-right direction to form a column Cg13, and the pixel regions Cg "2" and the pixel region Cg "4" are arranged side by side in the left-right direction to form a column Cg24. The column Cg24 of the pixel region Cg is provided at the interval in the front-rear direction between the columns Cg13 of this pixel region Cg. This interval is equal to the pitch b of the nozzles 21, and dots are formed for each of these pixel regions Cg. Therefore, even when the resolution of the image composed of dots is larger than the resolution of the head 20 based on the pitch b of the nozzles 21, an image can be printed by this head 20.

[0060] <Cutting process> While executing the first printing process on the printing medium A in this way, a cutting process for cutting the printing medium A is executed. As shown in FIG. 3, the control device 60 acquires the dimension a1 of the margin in the front-rear direction based on the printing conditions of the print job, and also acquires the dimension a2 between the downstream end C1 and the upstream end C2 of the printing region C in the front-rear direction based on the image data of the print job. Then, the control device 60 acquires, at the leading end A1 of the printing medium A, the position obtained by adding the sum of these dimensions (2×a1 + a2) as the cutting position A3. Then, when the cutting position A3 reaches the cutter 51 (FIG. 1) at a predetermined position, the control device 60 executes the cutting process.

[0061] Here, as shown in the example of FIG. 3, while the first conveyance operation is being executed such that the nozzle range 24 moves from the position p12 to the position p13 in the first printing process, the cutting position A3 may reach the cutter 51. In such a case, in the first conveyance operation, a conveyance amount d1a shorter than the first conveyance amount d1 is conveyed for the printed medium A, and the first conveyance operation is interrupted.

[0062] Then, the cutting process is executed with the nozzle range 24 stopped at a position p′ between the position p12 and the position p13, and the cutting position A3 of the printed medium A is cut by the cutter 51. After the execution of this cutting process, the first conveyance operation is resumed, and a conveyance amount d1b shorter than the first conveyance amount d1 is conveyed for the printed medium A, and the nozzle range 24 moves from the position p′ to the position p13. Then, the first pass operation is executed, and ink is ejected from the nozzle range 24 located at the position p13 to the first pass area Fa (area F12) of the printed medium A, and dots are formed in the first pass area Fa.

[0063] <Correction process> Since it is difficult to accurately convey the printed medium A with such short conveyance amounts d1a and d1b, the position of the dots by the first pass operation after the cutting process may deviate from the desired position, and the image quality may deteriorate. Therefore, as shown in FIG. 10, a correction process is executed to correct the first conveyance amount d1 in the first printing process so that the downstream end Fa1 in the conveyance direction in the first pass area Fa faces the downstream end 24e in the conveyance direction in the nozzle range 24 when the cutting process is executed.

[0064] This correction process is performed before the execution of the cutting process. For example, correction is performed on the first conveyance amount d1 in at least one first conveyance operation included in the first printing process. Hereinafter, the case of correcting the first conveyance amount d1 of the first first conveyance operation in the first printing process will be described, but the correction process is not limited to this. For example, the first conveyance amount d1 of other first conveyance operations other than the first first conveyance operation in the first printing process may be corrected. Also, the first conveyance amounts d1 of a plurality of first conveyance operations in the first printing process may be corrected.

[0065] Thus, in the first first conveyance operation in the first printing process, the first conveyance amount d1 is corrected. After the execution of this first first conveyance operation, the first first pass operation is executed. Then, the first conveyance operation with the uncorrected first conveyance amount d1 and the first pass operation are alternately executed. As a result, since the first pass images by all the first pass operations in the first printing process are formed for each constant first conveyance amount d1, it is possible to suppress deterioration of image quality due to differences in the conveyance amount.

[0066] As shown in FIG. 10, the first first conveyance operation is the first first conveyance operation performed immediately after the execution of the alignment process. By the correction process, the first conveyance amount d1 of the first conveyance operation to be corrected is corrected to a conveyance amount d1b shorter than the first conveyance amount d1 of the other first conveyance operations. This corrected first conveyance amount d1b is shorter by a conveyance amount d1a (= d - d1b) than the first conveyance amount d1 of the other first conveyance operations.

[0067] Immediately after this first first conveyance operation, the first first pass operation is executed, and ink is ejected from the nozzles 21 in the nozzle range 24 located at the position p1. When the correction process is executed as shown in FIG. 10 for the first first conveyance operation, the ink ejection range (white range) in the nozzle range 24 at the position p1 is narrower than when the correction process is not executed as shown in FIG. 3. Therefore, when the first first conveyance operation is corrected by the correction process as shown in FIG. 10, the number of nozzles 21 used in the first first pass operation is smaller than when the correction process is not executed as shown in FIG. 3.

[0068] Further, the correction process is performed on the first conveyance amount d1 of the first conveyance operation executed before the cutting process. As a result, at the time of execution of the cutting process, the nozzle range 24 is displaced from the position p' in FIG. 3 where the correction process is not performed to the position p12 and faces the first pass area Fa in the area F12. The downstream end 24e of this nozzle range 24 faces the downstream end Fa1 of the first pass area Fa, and the upstream end 24f of the nozzle range 24 faces the upstream end Fa2 of the first pass area Fa.

[0069] While the downstream end 24e of the nozzle range 24 faces the downstream end Fa1 of the first pass area Fa in this way, for example, since the first pass operation is performed, the printed medium A is not conveyed. By executing the cutting process while the printed medium A is stopped, the inter-pass conveyance, which is the first conveyance operation of the printed medium A performed between the first pass operations, is not interrupted due to the cutting process. Therefore, the conveyance amount of the printed medium A does not become shorter than the first conveyance amount d1 due to the interruption of the first conveyance operation, and a decrease in the conveyance accuracy of the printed medium A is suppressed. As a result, the occurrence of banding due to the cutting process of the long printed medium A can be suppressed.

[0070] In the example of FIG. 10, the control device 60 performed the correction process for the first conveyance operation at the beginning in the first printing process, but may perform the correction process for the first conveyance operations other than the first conveyance operation at the beginning. In this case, the first pass operation is executed before and after the first conveyance operation that is the target of the correction process. The first pass image formed by the first pass operation before this first conveyance operation and the first pass image formed by the first pass operation after the first conveyance operation are shifted by the corrected first conveyance amount d1b. Since this corrected first conveyance amount d1b is shorter than the first conveyance amount d1, it is possible to prevent a wide gap from being formed between these first pass images.

[0071] <Control Method of Printing Apparatus> The printing apparatus 10 is controlled by the control device 60 according to a flowchart showing an example of the control method in FIG. 11. The control device 60 acquires a print job from the communication interface 63 or the storage unit 62 (step S10), and also acquires detection signals from the conveyance sensor 48 and the encoder 46 of the conveyance motor 45 (step S11).

[0072] Next, the control device 60 executes alignment processing (step S12). In this alignment processing, the control device 60 adds a margin dimension a1 based on the printing conditions of the print job to the leading end A1 of the print medium A based on the detection signals of the conveyance sensor 48 and the encoder 46 of the conveyance motor 45, and acquires the downstream end C1 of the print area C. Then, the control device 60 conveys the print medium A in the front-rear direction so that this downstream end C1 faces the upstream end 24f of the nozzle range 24 of the head 20.

[0073] Also, the control device 60 determines whether or not the downstream end Fa1 of the first pass area Fa faces the downstream end 24e of the nozzle range 24 when executing the cutting process (step S13). Here, the control device 60 acquires the position of the nozzle range 24 and the position of the first pass area Fa facing the nozzle range 24 by shifting by a first conveyance amount d1 based on the printing conditions of the print job from the position p0 by the alignment process. Further, the control device 60 acquires a cutting position A3 obtained by adding the margin dimension a1 and the dimension a2 of the print area C based on the image data of the print job to the downstream end C1 of the print area C. Then, when the cutting position A3 reaches the cutter 51 during the execution of the first printing process, the position of the first pass area Fa facing the nozzle range 24 is acquired, and it is determined whether or not the downstream end Fa1 of the first pass area Fa faces the downstream end 24e of the nozzle range 24.

[0074] In step S13, when the downstream end Fa1 of the first pass area Fa does not face the downstream end 24e of the nozzle range 24 (step S13: NO), the cutting process is performed during the execution of the first conveyance operation. To avoid this, the control device 60 executes a correction process for the first conveyance amount d1 (step S14). In this correction process, the control device 60 corrects the first conveyance amount d1 to the first conveyance amount d1b so that the downstream end Fa1 of the first pass area Fa faces the downstream end 24e of the nozzle range 24 when the cutting process is executed. As a result, the cutting process is executed in a state where the printed medium A that is not being conveyed is stopped without interrupting the first conveyance operation for the cutting process. Therefore, it is possible to reduce the dot position deviation due to the interruption of the first conveyance operation and suppress the occurrence of banding caused by the cutting process of the long printed medium A.

[0075] Also, when the downstream end Fa1 of the first pass area Fa faces the downstream end 24e of the nozzle range 24 (step S13: YES), or after the execution of the correction process in step S14, the control device 60 executes the first printing process. In this first printing process, the control device 60 executes the first conveyance operation and conveys the printed medium A with the first conveyance amount d1 without the correction process in step S14, or the first conveyance amount d1b corrected by the correction process in step S14 (step S15). As a result, the nozzle range 24 moves from the position p0 by the alignment process to the position p1. Then, the control device 60 executes the first pass operation (step S16), and while the nozzle range 24 moves in the left - right direction at the position p1, ink is ejected from the nozzles 21 of the nozzle range 24. Thereby, dots are formed in the first pass area Fa facing the nozzle range 24, and a first pass image composed of the dots is formed.

[0076] Also, the control device 60 determines whether or not the cutting position A3 of the printed medium A has reached the cutter 51 (step S17). Here, if the cutting position A3 of the printed medium A has reached the cutter 51 (step S17: YES), the control device 60 executes the cutting process and cuts the cutting position A3 of the printed medium A with the cutter 51 (step S18).

[0077] Then, after executing the cutting process in step S18, or if the cutting position A3 of the print medium A has not reached the cutter 51 (step S17: NO), the control device 60 determines whether all the first pass operations based on the print job have been executed (step S19). Here, if there are remaining first pass operations that have not been executed (step S19: NO), the control device 60 returns to the process of step S15 and executes the subsequent processes. On the other hand, if the control device 60 has executed all the first pass operations (step S19: YES), it ends the process.

[0078] (Second Embodiment) As shown in FIG. 3, the printing apparatus 10 according to the first embodiment prints an image on the print medium A by the first printing process. In contrast, as shown in FIG. 12, the printing apparatus 10 according to the second embodiment prints an image on the print medium A by a second printing process executed before the first printing process in addition to the first printing process. The second printing process includes a second pass operation, and by the second pass operation, ink is ejected onto a second pass area Fb which is a part of the printing area C to form a second pass image. Hereinafter, the first pass operation and the second pass operation may be referred to as pass operations, the first pass area Fa and the second pass area Fb may be referred to as pass areas, and the first pass image and the second pass image may be referred to as pass images.

[0079] <Second Printing Process> The second printing process includes a second pass operation and a second conveyance operation, and the second pass operation and the second conveyance operation are executed alternately. In the second pass operation, the control device 60 ejects ink from the nozzles 21 of the head 20 onto the second pass area Fb of the print medium A while moving the head 20 to the right or left. As a result, dots are formed in the second pass area Fb, and a second pass image composed of the dots is formed. This second pass area Fb is an area of the print medium A that faces the nozzle range 24 of the head 20 in the second pass operation, and is an area where ink can be ejected from the nozzles 21 of the nozzle range 24 by one second pass operation. In the front-rear direction, the dimension of the second pass area Fb is equal to the dimension e of the nozzle range 24.

[0080] In the second conveyance operation, the control device 60 conveys the printing medium A forward to the second conveyance amount d2, the third conveyance amount d3, or the fourth conveyance amount d4 with respect to the head 20. The fourth conveyance amount d4 is the conveyance amount of the printing medium A by the first second conveyance operation in the second printing process after the alignment process. The third conveyance amount d3 is shorter than the first conveyance amount d1, and is set such that a part of the second pass area Fb targeted for the current second pass operation overlaps a part of the second pass area Fb targeted for the previous second pass area Fb. The second conveyance amount d2 is longer than the first conveyance amount d1, and is determined based on the position of the leading end A1 of the printing medium A with respect to the upstream roller 43 and the downstream roller 44 as shown in FIG. 1.

[0081] That is, as shown in FIG. 1, since the printing medium A is drawn out from the roll body Ar wound in a roll shape, it has a curl. For this reason, when the printing medium A curls, depending on the position of the leading end A1 (FIG. 3) of the printing medium A, the leading end A1 may stick to the discharge surface 22 of the head 20, and the printing medium A may be soiled. Therefore, the second conveyance amount d2 is set so that the second pass operation at a position where such a printing medium A is likely to stick to the discharge surface 22 is not performed.

[0082] When the leading end A1 of the printing medium A is downstream of the clamping position j1 of the pair of upstream rollers 43 and upstream of the clamping position j2 of the pair of downstream rollers 44, the printing medium A is in a cantilever state where it is clamped by the upstream rollers 43 without being clamped by the downstream rollers 44. In this state, the leading end A1 of the printing medium A is positioned between the discharge surface 22 and the platen 11 in the vertical direction, and when the printing medium A curls, its leading end A1 will stick to the discharge surface 22.

[0083] However, even in such a state, when the leading end A1 of the printing medium A is located between the clamping position j1 and a predetermined position j4 at a predetermined dimension j3 downstream of the clamping position j1, the dimension of the printing medium A extending downstream from the clamping position j1 is shorter than the predetermined dimension j3. For this reason, due to the tension of the printing medium A, the leading end A1 is difficult to adhere to the ejection surface 22. Therefore, while the leading end A1 is located between the clamping position j1 and the predetermined position j4, the second pass operation and the second conveyance operation conveyed at the third conveyance amount d3 are alternately executed on the printing medium A.

[0084] Furthermore, when the printing medium A is further conveyed and its leading end A1 is located between the predetermined position j4 and the clamping position j2, the dimension of the printing medium A extending upstream from the clamping position j1 becomes longer than or equal to the predetermined dimension j3. In this case, there is a risk that the curled leading end A1 of the printing medium A may adhere to the ejection surface 22. Therefore, when the leading end A1 of the printing medium A is located between the clamping position j1 and the predetermined position j4, the second pass operation is not executed on the printing medium A, and the second conveyance operation that conveys by the second conveyance amount d2 corresponding to the interval j5 between the clamping position j1 and the predetermined position j4 is executed.

[0085] Furthermore, when the printing medium A is further conveyed and its leading end A1 is located downstream of the predetermined position j4, the printing medium A is in a both-end supported state clamped by the upstream roller 43 and the downstream roller 44, and the leading end A1 is difficult to adhere to the ejection surface 22. For this reason, the second pass operation and the second conveyance operation conveyed at the third conveyance amount d3 are alternately executed on the printing medium A. After this second printing process, the first printing process is executed, and the first conveyance operation and the first pass operation are alternately executed.

[0086] <Multi-pass method> The cycle of the multi-pass method of the second printing process is set by (image resolution / head 20 resolution × singling number), similar to the first printing process, and is 4 cycles in the example of FIG. 12. In this case, when the nozzle range 24 is arranged at each of the positions p1 to p8, the second pass operation of the second printing process is executed, and when the nozzle range 24 is arranged at each of the positions p9 to, the first pass operation of the first printing process is executed.

[0087] Among these, when the nozzle range 24 is located at the position p(4n - 3) (n is a natural number), the first pass operation or the second pass operation of the first cycle is executed. When the nozzle range 24 is located at the position p(4n - 2), the first pass operation or the second pass operation of the second cycle is executed. When the nozzle range 24 is located at the position p(4n - 1), the first pass operation or the second pass operation of the third cycle is executed. When the nozzle range 24 is located at the position p(4n), the first pass operation or the second pass operation of the fourth cycle is executed.

[0088] For example, after the nozzle range 24 is aligned with the position p0 by the alignment process, the first second conveyance operation of the second printing process is executed, and the print medium A is conveyed forward by the fourth conveyance amount d4, and the nozzle range 24 moves from the position p0 to the position p1. Here, the second pass operation of the first cycle is executed, and ink is ejected from the nozzle 21 of the nozzle range 24 located at the position p1 to the second pass area Fb of the area F1 to form a second pass image.

[0089] Then, by the second second conveyance operation of the second printing process, the print medium A is conveyed forward by the third conveyance amount d3, and the nozzle range 24 moves from the position p1 to the position p2. Here, by the second pass operation of the second cycle, ink is ejected from the nozzle 21 of the nozzle range 24 located at the position p2 to the second pass area Fb of the area F2 to form a second pass image.

[0090] In this way, in the second printing process, the second conveyance operation and the second pass operation are alternately repeated. Among these, the second conveyance operation with the third conveyance amount d3 is performed, and the nozzle range 24 moves to each of the positions p1 to p4. At each of these positions, the second pass operations of the first to fourth cycles are executed, and these second pass images are overlapped. Then, the second conveyance operation with the second conveyance amount d2 is performed, and the nozzle range 24 moves from the position p4 to the position p5. Also, the second conveyance operation with the third conveyance amount d3 is performed, and the nozzle range 24 moves to each of the positions p5 to p8. At each of these positions, the second pass operations of the first to fourth cycles are executed, and these second pass images are overlapped.

[0091] After the execution of the last second pass operation in this second printing process, the first conveyance operation of the first printing process is executed, and the printing medium A is conveyed forward by a first conveyance amount d1, and the nozzle range 24 moves from position p8 to position p9. Here, the first pass operation of the first cycle is executed, and ink is ejected from the nozzles 21 of the nozzle range 24 located at position p9 to the first pass area Fa of area F9 to form a first pass image. In this way, in the first printing process, the first conveyance operation of the first conveyance amount d1 and the first pass operation are alternately repeated.

[0092] In this way, in the printing area C, the pass images formed by the first pass operation or the second pass operation in the first cycle to the fourth cycle are overlapped. In this case, the printing area C has a downstream end portion C3 and another portion C4 other than the downstream end portion C3. The downstream end portion C3 includes a downstream portion C3a and an upstream portion C3b upstream of the downstream portion C3a.

[0093] The second pass operation is executed for this downstream portion C3a without executing the first pass operation, the first pass operation and the second pass operation are executed for the upstream portion C3b, and the first pass operation is executed for the other portion C4 without executing the second pass operation. For this reason, the second printing process is executed for the downstream end portion C3 including the downstream portion C3a and the upstream portion C3b. Four second pass images are stacked on the downstream portion C3a, four pass images are stacked on the upstream portion C3b, and four first pass images are stacked on the other portion C4.

[0094] <Singling> When a plurality of pass images are overlapped by the first printing process and the second printing process, singling is performed to disperse the dots constituting the pass image in the left-right direction. In the example of FIG. 12, the pass operation of the first cycle and the pass operation of the third cycle are taken as one set, and the pass operation of the second cycle and the pass operation of the fourth cycle are taken as one set, and singling is performed for each set.

[0095] According to FIG. 13(a) showing the position of the nozzle range 24 with respect to the printing area C in FIG. 12, the pass operation in the first cycle is executed when the nozzle range 24 is located at position p(4n - 3) (n is a natural number). The pass operation in the second cycle is executed when the nozzle range 24 is located at position p(4n - 2). The pass operation in the third cycle is executed when the nozzle range 24 is located at position p(4n - 1). The pass operation in the fourth cycle is executed when the nozzle range 24 is located at position p(4n).

[0096] FIG. 13(b) shows the dot formation rate by the pass operation in the first cycle, FIG. 13(c) shows the dot formation rate by the pass operation in the second cycle, FIG. 13(d) shows the dot formation rate by the pass operation in the third cycle, and FIG. 13(e) shows the dot formation rate by the pass operation in the fourth cycle. In FIGS. 13(b) to 13(e), by gradation singling, the dot formation rate by one first pass operation has a gradient that changes from 0 to 100 (%). Here, the sum of the formation rates of the first cycle and the third cycle that make up the set is 100%, and the sum of the formation rates of the second cycle and the fourth cycle that make up the set is 100%. According to this formation rate, the dots formed by the pass operation are dispersed in the left - right direction.

[0097] <Interlace> Similar to the first pass operation, as shown in FIG. 9, dots are respectively formed in the pixel regions Cg "1" to "4" by the second pass operations in the first to fourth cycles. The column Cg13 of the pixel regions Cg "1" and Cg "3" arranged in the left - right direction, and the column Cg24 of the pixel regions Cg "2" and Cg "4" arranged in the left - right direction are arranged in the front - rear direction. The column Cg24 is provided at the interval in the front - rear direction between the columns Cg13. The interval in the front - rear direction between the columns Cg13 is equal to the pitch b of the nozzle 21, and dots are formed for each of these pixel regions Cg. Therefore, even when the resolution of the image composed of dots is larger than the resolution of the head 20 based on the pitch b of the nozzle 21, the image can be printed by this head 20.

[0098] <Cutting process> While performing the first printing process and the second printing process on the printing medium A in this way, a cutting process for cutting the printing medium A is executed. The control device 60 acquires the cutting position A3 from the printing conditions of the printing job, and when the cutting position A3 reaches the cutter 51, cuts the printing medium A at the cutting position A3 with the cutter 51. For example, as shown in FIG. 12, while the first conveyance operation is being executed such that the nozzle range 24 moves from the position p15 to the position p16 in the first printing process, the cutting position A3 may reach the cutter 51. In such a case, the first conveyance operation is interrupted and the cutting process is executed.

[0099] <Correction process> When the first conveyance operation is interrupted in this way, since the conveyance amounts d1a and d1b before and after the interruption are shorter than the first conveyance amount d1, the conveyance accuracy decreases, and there is a risk that the image quality will deteriorate. Therefore, as shown in FIG. 14, a correction process is executed to correct the first conveyance amount d1 in the first printing process so that the downstream end Fa1 in the conveyance direction in the first pass area Fa faces the downstream end 24e in the conveyance direction in the nozzle range 24 when the cutting process is executed. As a result, since the first conveyance operation of the printing medium A is not executed when the cutting process is executed, the first conveyance operation is not interrupted due to the cutting process, and the occurrence of banding caused by the cutting process can be suppressed.

[0100] This correction process is performed on the first conveyance amount d1 in at least one first conveyance operation included in the first printing process. Hereinafter, the case of correcting the first conveyance amount d1 of the first conveyance operation will be described, but the correction process is not limited to this. For example, the first conveyance amount d1 of a first conveyance operation other than the first conveyance operation may be corrected. Also, the first conveyance amounts d1 of a plurality of first conveyance operations may be corrected. However, in any case, the correction process is executed before the cutting process. By this correction process, the first conveyance amount d1 of the first conveyance operation executed before the cutting process is corrected.

[0101] Also, as shown in FIG. 14, for example, the correction process corrects the first conveyance amount d1 in the first printing process during the first first conveyance operation. This first first conveyance operation is the first first conveyance operation performed immediately after the execution of the second pass operation of the second printing process. Thereby, all the first pass operations are executed after the minimum first conveyance operation of the correction process. Therefore, since all the first pass images in the first printing process are formed for each constant first conveyance amount d1, it is possible to suppress a decrease in image quality due to a difference in conveyance amount.

[0102] Furthermore, the correction process corrects the first conveyance amount d1 to be corrected to a conveyance amount d1b shorter than the other first conveyance amounts d1. Thereby, it is possible to prevent a wide gap from being formed between the first pass images formed by the first pass operation before and after the corrected first conveyance operation. Also, when the correction process is executed for the first first conveyance operation in the first printing process as shown in FIG. 14, the ink ejection range (white range) in the nozzle range 24 at the position p9 is narrower than when the correction process is not executed as shown in FIG. 12. Therefore, when the first conveyance amount d1 of the first first conveyance operation is corrected by the correction process as shown in FIG. 14, the number of nozzles 21 used in the first first pass operation is smaller than when it is not corrected by the correction process as shown in FIG. 12.

[0103] <Control Method of Printing Device> The printing device 10 is controlled by the control device 60 according to a flowchart showing an example of the control method in FIG. 15. In the flowchart of FIG. 15, the processes of steps S20 to S22 are executed between the process of step S12 and the process of step S13 in the flowchart of FIG. 11.

[0104] Specifically, the control device 60 acquires a print job from the communication interface 63 or the storage unit 62 (step S10), and acquires detection signals from the conveyance sensor 48 and the encoder 46 of the conveyance motor 45 (step S11). Then, the control device 60 executes alignment processing based on the print job and the detection signals (step S12), and then executes second printing processing. In this second printing processing, the control device 60 executes a second conveyance operation of the second conveyance amount d2 or the third conveyance amount d3 (step S20), and then executes a second pass operation (step S21).

[0105] By this second pass operation, the control device 60 discharges ink from the nozzles 21 in the nozzle range 24 while the nozzle range 24 moves in the left-right direction. Thereby, dots are formed in the second pass area Fb facing the nozzle range 24, and a second pass image composed of the dots is formed. Then, the control device 60 determines whether or not all the second pass operations based on the print job have been executed (step S22). Here, if there are remaining second pass operations that have not been executed (step S22: NO), the control device 60 returns to the process of step S20 and executes the subsequent processes.

[0106] On the other hand, when the control device 60 has executed all the second pass operations (step S22: YES), it determines whether or not the downstream end Fa1 of the first pass area Fa faces the downstream end 24e of the nozzle range 24 when the cutting process is executed (step S13). Here, when the downstream end Fa1 of the first pass area Fa does not face the downstream end 24e of the nozzle range 24 (step S13: NO), the cutting process is performed during the execution of the first conveyance operation. To avoid this, the control device 60 executes correction processing of the first conveyance amount d1 (step S14). Then, the control device 60 executes first printing processing and cutting processing based on the print job (steps S15 to S19).

[0107] <Other Modification Examples> In the above-described entire embodiment, a bidirectional printing method will be described in which a first pass operation of discharging ink while the head 20 moves to the right and a first pass operation of discharging ink while the head 20 moves to the left are alternately repeated. However, a unidirectional printing method may be employed in which the head 20 discharges ink while moving in one of the right and left directions without discharging ink while moving in the other of the right and left directions.

[0108] The above entire embodiments may be combined with each other as long as they do not mutually exclude each other. Further, from the above description, many improvements and other embodiments of the present disclosure will be apparent to those skilled in the art. Accordingly, the above description should be construed as illustrative only and provided for the purpose of teaching those skilled in the art of the best mode of carrying out the present disclosure. Without departing from the spirit of the present disclosure, the details of its structure and / or function may be substantially changed.

Explanation of Reference Numerals

[0109] 10: Printing apparatus 13: Supply tray 20: Head 21: Nozzle 22: Discharge surface 24: Nozzle range 24e: Downstream end 24f: Upstream end 30: Moving device 40: Conveying device 51: Cutter 60: Control device

Claims

1. A supply tray for supplying a printing medium, A head having a discharge surface including a nozzle range provided with a plurality of nozzles for discharging ink onto the printing medium, A moving device for moving the head in a moving direction, A conveying device for conveying the printing medium along a conveying direction intersecting the moving direction, A cutter disposed closer to the supply tray than the head for cutting the printing medium, A control device, comprising: The control device: A first pass operation of discharging ink from the nozzles into a first pass area of the printing medium while moving the head along the moving direction by the moving device, and a first conveyance operation of conveying the printing medium by a first conveyance amount equal to or less than the dimension of the nozzle range in the conveying direction by the conveying device; a recording process including these operations is repeated a plurality of times, and a first printing process of overlapping a part of the first pass area targeted by the first pass operation of the current recording process with a part of the first pass area targeted by the first pass operation of the previous recording process; A cutting process of cutting the printing medium by the cutter; A correction process of correcting the first conveyance amount in the first printing process so that a downstream end in the conveying direction in the first pass area faces a downstream end in the conveying direction in the nozzle range when the cutting process is executed; The cutter cuts the printing medium after the correction process is executed. A printing apparatus.

2. The control device performs a second printing process of performing a second pass operation of discharging ink from the nozzles into a second pass area of the printing medium while moving the head along the moving direction by the moving device with respect to a downstream end portion of the printing area of the printing medium, and a second conveyance operation of conveying the printing medium by a second conveyance amount longer than the first conveyance amount by the conveying device; The first printing process is executed after the second printing process; The correction process is executed with respect to the first conveyance amount in at least one of the first conveyance operations included in the first printing process. The printing apparatus according to Claim 1.

3. The correction process is executed with respect to the first conveyance amount of the first conveyance operation at the beginning of the first printing process. The printing apparatus according to Claim 2.

4. By the correction process, the first conveyance amount to be corrected is corrected to a conveyance amount shorter than other first conveyance amounts. The printing apparatus according to Claim 2.

5. When the first conveyance amount in the first conveyance operation is corrected by the correction process, the first pass operation uses fewer nozzles immediately after the first conveyance operation than when not corrected by the correction process. The printing apparatus according to claim 2.

6. The control device executes an alignment process of aligning the downstream end of the printing area of the print medium with the upstream end in the conveyance direction in the nozzle range. The first printing process is executed after the alignment process. The correction process is executed for the first conveyance amount in at least one first conveyance operation included in the first printing process. The printing apparatus according to claim 1.

7. The correction process is executed for the first conveyance amount of the first conveyance operation at the beginning in the first printing process. The printing apparatus according to claim 6.

8. By the correction process, the first conveyance amount to be corrected is corrected to a conveyance amount shorter than the other first conveyance amounts. The printing apparatus according to claim 6.

9. When the first conveyance amount in the first conveyance operation is corrected by the correction process, the first pass operation uses fewer nozzles immediately after the first conveyance operation than when not corrected by the correction process. The printing apparatus according to claim 6.

10. A supply tray for supplying a print medium; A head having a discharge surface including a nozzle range provided with a plurality of nozzles for discharging ink onto the print medium; A moving device for moving the head in a moving direction; A conveyance device for conveying the print medium along a conveyance direction intersecting the moving direction; A control method for a printing apparatus including a cutter disposed closer to the supply tray than the head and configured to cut the print medium, the method including: A first pass operation of discharging ink from the nozzles into a first pass area of the print medium while moving the head along the moving direction by the moving device, and a first conveyance operation of conveying the print medium by a first conveyance amount equal to or less than the dimension of the nozzle range in the conveyance direction by the conveyance device, the recording step including repeating the recording step a plurality of times, and a first printing process of overlapping a part of the first pass area targeted by the first pass operation in the current recording step with a part of the first pass area targeted by the first pass operation in the previous recording step; A cutting process of cutting the print medium by the cutter. Execute a correction process for correcting the first conveyance amount in the first printing process so that the downstream end in the conveyance direction in the first pass area faces the downstream end in the conveyance direction in the nozzle range when the cutting process is executed. Cut the printed medium with the cutter after the execution of the correction process. A control method for a printing apparatus.

11. A supply tray for supplying a printed medium. A head having a discharge surface including a nozzle range provided with a plurality of nozzles for discharging ink onto the printed medium. A moving device for moving the head in a moving direction. A conveyance device for conveying the printed medium along a conveyance direction intersecting the moving direction. To a computer of a printing apparatus including a cutter disposed closer to the supply tray than the head and configured to cut the printed medium. A first pass operation of discharging ink from the nozzles into a first pass area of the printed medium while moving the head along the moving direction by the moving device, and a first conveyance operation of conveying the printed medium by a first conveyance amount equal to or less than the dimension of the nozzle range in the conveyance direction by the conveyance device. Repeatedly perform a recording process including these operations a plurality of times, and perform a first printing process of overlapping a part of the first pass area targeted by the first pass operation in the current recording process with a part of the first pass area targeted by the first pass operation in the previous recording process. A cutting process of cutting the printed medium with the cutter. Execute a correction process for correcting the first conveyance amount in the first printing process so that the downstream end in the conveyance direction in the first pass area faces the downstream end in the conveyance direction in the nozzle range when the cutting process is executed. Cut the printed medium with the cutter after the execution of the correction process. A computer program.

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