JP2009262381A - Controller, printing apparatus, method for controlling controller, and controlling program for controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To generate printing data having a high possibility and suitable to a conveying position of an objective printing medium. <P>SOLUTION: An inkjet printer acquires a detecting signal indicating the conveying position related to the width direction of a paper conveyed before one of an objective paper to be an object on which an image is to be recorded (S3). Then, using the detecting signal, based on the image data for the objective paper, the printing data for the objective paper are formed (S7). By providing the printing data to an inkjet head, ink is delivered from each inkjet head and printing on the objective paper is performed (S15). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a printing apparatus, and more particularly to a technique for generating print data.

  An image recording apparatus (printing apparatus) described in Patent Document 1 includes a transport mechanism that transports a recording medium along the transport direction, and a 2 that extends in the width direction perpendicular to the transport direction and is disposed along the transport direction. And two recording heads (former). Each recording head has nozzles formed in a line along the width direction, and the ink is ejected from each nozzle of the two recording heads to the recording medium conveyed by the conveyance mechanism, so that a full line is formed on the recording medium. An image can be formed. Further, upstream of the conveyance path along which the recording medium is conveyed, a recording medium side edge detection unit is provided for detecting the edges of the both sides of the recording medium in the width direction, that is, the lateral displacement amount of the recording medium. . Then, the image recording apparatus generates print data to be given to the two recording heads based on the lateral deviation amount of the recording medium conveyed in the conveyance direction by the conveyance mechanism.

JP 2006-35852 A (FIG. 1)

  By the way, when the position of the recording medium side edge detection unit and the positions of the two recording heads are close to each other in the conveyance direction or when the recording medium conveyance speed is high, the recording medium is positioned below the recording medium side edge detection unit. It takes a short time to reach the position facing the two recording heads after passing through. For this reason, there has been a problem that the case where the generation of print data is not in time may occur.

  Accordingly, an object of the present invention is to provide a technique capable of generating print data that is highly likely to be suitable for the transport position of a target print medium at an early stage.

  A control device according to the present invention includes a transport unit that transports a print medium in a first direction, a detection unit that detects a transport position of the print medium in a second direction intersecting the first direction, and a print medium based on print data A control unit that controls a print execution unit including an image forming unit, an acquisition unit that acquires a detection result indicating the transport position of the print medium from the detection unit, and target printing of an image formation target A print data generating unit that generates the print data for forming an image on the target print medium using a detection result indicating the transport position of at least one preceding print medium transported by the transport unit before the medium And.

  The transport position of the target print medium that is the target of image formation is expected to be substantially the same as the transport position of the preceding print medium that is transported before the target print medium. Therefore, in the control device of the present invention, the print data for the target print medium is generated using the detection result indicating the transport position of the preceding print medium transported before the target print medium. Therefore, according to the control apparatus of the present invention, it is possible to early generate print data that is highly likely to be suitable for the transport position of the target print medium.

  In addition, it is preferable that the at least one preceding print medium includes a print medium that the transport unit transports to the front of the target print medium. In this case, the transport position of the target print medium is highly likely to be substantially the same as the transport position of the preceding print medium transported immediately before the target print medium. Therefore, it is possible to generate print data that has a high possibility of being more suitable for the transport position of the target print medium.

  Further, the at least one preceding print medium is one preceding print medium, and the print data generation unit uses only the detection result indicating the transport position of the one preceding print medium, and the target print medium. It is preferable to generate the print data for. According to this, processing becomes easier as compared with the case where a plurality of print media are used as the preceding print media.

  Further, the at least one preceding print medium is two or more preceding print media, and the print data generation unit uses the two or more detection results indicating the transport positions of the two or more preceding print media, An estimation unit that estimates a transport position of the target print medium, and the print data generation unit generates the print data for the target print medium using the estimation result estimated by the estimation unit Good. According to this, since the position of the target print medium can be estimated, it is possible to generate print data that is more likely to be more suitable for the transport position of the target print medium.

  At this time, it is preferable that the two or more preceding print media include a print medium that the transport unit transports one and two before the target print medium. According to this, it is possible to estimate the transport position of the target print medium more accurately.

  In the case where images are continuously formed on the plurality of print media by the forming unit, the preceding print medium is a first print medium that is first transported by the transport unit among the plurality of print media. And the print data generation unit uses the first detection result indicating the transport position of the first print medium, and uses one or more of the plurality of print media that are image formation targets other than the first print medium. Preferably, the print data for the print medium is generated. According to this, only the transport position of the first print medium needs to be detected by the detection unit, and the number of detections by the detection unit can be reduced.

  Furthermore, it is preferable that the print data generation unit further generates first print data for forming an image on the first print medium, using the first detection result. According to this, the first print data for the first print medium can be generated using the detection result indicating the transport position of the self (first print medium).

  In addition, the forming unit includes a first nozzle group arranged along the second direction, and a second nozzle group arranged along the second direction, and the first nozzle group And the second nozzle group are arranged at different positions with respect to the first direction, and each nozzle of the first nozzle group and each nozzle of the second nozzle group are at different positions with respect to the second direction. Preferably, the print data generation unit generates the print data so as to match the nozzle arrangement of the forming unit. In such a nozzle arrangement of each nozzle of the first nozzle group and each nozzle of the second nozzle group, the effect of using the present invention becomes more remarkable.

  The printing apparatus of the present invention includes any one of the above-described control devices and the print execution unit. The transport position of the target print medium that is the target of image formation is expected to be substantially the same as the transport position of the preceding print medium that is transported before the target print medium. Therefore, in the control device of the present invention, the print data for the target print medium is generated using the detection result indicating the transport position of the preceding print medium transported before the target print medium. Therefore, according to the control apparatus of the present invention, it is possible to early generate print data that is highly likely to be suitable for the transport position of the target print medium. Therefore, an image can be quickly formed based on the print data.

  In another aspect, a printing apparatus of the present invention includes the above-described control device and the print execution unit. The conveyance unit interrupts conveyance of the first print medium after the acquisition unit acquires the first detection result, and after the print data generation unit starts generation of the first print data, 1 Transport of the print medium is resumed. According to the printing apparatus of the present invention, it is possible to secure the time required for generating the first print data by interrupting the conveyance of the first print medium.

  Furthermore, from another viewpoint, the printing apparatus of the present invention includes the above-described control device and the print execution unit. The transport unit transports the first print medium a plurality of times so as to face the detection unit and the forming unit, and the detection unit performs the first transport of the first print medium by the transport unit, The first detection result indicating the transport position of the first print medium is detected, and the forming unit is generated using the first detection result in the second and subsequent transports of the first print medium by the transport unit. An image is formed on the first print medium based on the first print data. According to the printing apparatus of the present invention, the time required for generating the first print data can be secured by conveying the first print medium a plurality of times.

  The present invention is applied to various aspects such as a control device and method, a printing device and method including the control device, a computer program for realizing the functions of these methods or devices, and a recording medium on which the computer program is recorded. It is feasible.

  For example, the present invention may be realized by another printing apparatus. Specifically, another printing apparatus includes a transport unit that transports a print medium in a first direction, a detection unit that detects a transport position of the print medium in a second direction that intersects the first direction, and an image formation target. Print data for generating print data for forming an image on the target print medium using a detection result indicating the transport position of at least one preceding print medium transported by the transport unit before the target print medium You may provide the production | generation part and the formation part which forms an image in the said object print medium based on the said print data.

  The transport position of the target print medium that is the target of image formation is expected to be substantially the same as the transport position of the preceding print medium that is transported before the target print medium. Therefore, in the control device of the present invention, the print data for the target print medium is generated using the detection result indicating the transport position of the preceding print medium transported before the target print medium. Therefore, according to the control apparatus of the present invention, it is possible to early generate print data that is highly likely to be suitable for the transport position of the target print medium.

<First Embodiment>
Hereinafter, a preferred first embodiment of the present invention will be described with reference to the drawings. The first embodiment is an example in which the present invention is applied to an inkjet printer that ejects ink onto paper and records characters, images, and the like.

  FIG. 1 is a schematic configuration diagram of an ink jet printer according to a first embodiment of the present invention. As shown in FIG. 1, an inkjet printer 1 as a printing apparatus has a rectangular parallelepiped casing 1a, and a paper discharge unit 6 is provided on the upper part. In the housing 1a, four ink jet heads 2 (formers) for ejecting magenta, cyan, yellow, and black inks in order from the top, the transport direction C (left to right in FIG. 1, right direction: first direction) In addition, a transport unit 40 (transport unit) that transports the paper P, which is a print medium, and a paper feeding device 23 are disposed. In addition, an alignment mechanism (not shown) that aligns the paper P with the head center is provided inside the inkjet printer 1.

  Further, in the housing 1 a, the paper P is reversed from the paper transport path 20 through which the paper P is transported from the paper feeding device 23 toward the paper discharge unit 6 and from the downstream side to the upstream side of the transport unit 40. A sheet reversing path 70 to be conveyed again is formed.

  The paper feeding device 23 transports the uppermost paper P among the paper feeding cassettes 24 that can store the plurality of stacked paper sheets P and the plurality of paper sheets P that are stacked and stored in the paper feeding cassette 24. A sheet feeding roller 25 that feeds the sheet 20 to the path 20 one by one and a sheet feeding motor 132 (see FIG. 6) that is controlled by the control unit 100 and rotates the sheet feeding roller 25 are provided.

  In this configuration, the paper P fed out from the paper feed cassette 24 by the rotation of the paper feed roller 25 under the control of the control unit 100 is guided by the transport guides 26, 27, 28 and is sandwiched between the feed roller pairs 21, 22. Then, the sheet is sent to the transport unit 40 so that one surface thereof faces the inkjet head 2. One roller of the pair of feed rollers 21 and 22 is a driven roller that rotates by driving of a feed motor 134 (see FIG. 6), and the other roller rotates as the one roller rotates. Further, the feed motor 134 is controlled by the control unit 100. The conveyance guide 26 branches from the midway portion thereof to the downstream side of the sheet reversing path 70. That is, the transport guide 26 guides the paper P transported from the paper feed cassette 24 and the paper reversing path 70.

  The transport unit 40 includes a pair of belt rollers 41 and 42, an endless transport belt 43 wound around the rollers 41 and 42, a pressing roller 4, and a transport motor that rotates the belt roller 42. 133 (see FIG. 6). Silicone treatment is applied to the outer peripheral surface of the conveyor belt 43, that is, the conveyor surface 44, and the conveyor surface 44 has adhesiveness. The pressing roller 4 is disposed above the belt roller 41 and at a position sandwiching the conveyance belt 43 with the belt roller 41. The pressing roller 4 is urged toward the transport surface 44 by an elastic member such as a spring (not shown), and presses the paper P transported by the feed roller pair 22 against the transport surface 44.

  In this configuration, the conveyor belt 43 is rotated by rotating the belt roller 42 in the clockwise direction in FIG. 1 under the control of the control unit 100. At this time, the belt roller 41 and the pressing roller 4 that are driven rollers also rotate as the conveying belt 43 rotates. As a result, the paper P is held on the transport surface 44 of the transport belt 43 and transported in the transport direction C. At this time, when the paper P held and transported by the transport surface 44 sequentially passes immediately below the four ink jet heads 2, the control unit 100 controls each ink jet head 2, whereby each ink jet head 2. The ink of each color is ejected from the paper to the paper P, and a desired color image is formed on the paper P.

  Between the pressure roller 4 and the inkjet head 2, a paper position detection sensor 50 and a paper leading edge detection sensor 51 are provided in order from the upstream side of the conveyance path (conveyance direction). The paper position detection sensor 50 is a line type sensor made of, for example, a CCD, a CMOS, or the like having an imaging range extending in the width direction (the direction perpendicular to the transport direction and perpendicular to the paper surface in FIG. 1: the second direction). It is. The imaging range of the sheet position detection sensor 50 is slightly longer than the sheet P conveyed on the conveying surface 44 in the width direction, and the sheet P shifted in the width direction can also be imaged. The paper position detection sensor 50 detects the transport position in the width direction of the paper P transported on the transport surface 44 by imaging and reading the paper P. The transport position detected by the paper position detection sensor 50 is output to the control unit 100 as a detection result.

  The paper leading edge detection sensor 51 is, for example, an optical reflection type or transmission type sensor. The sheet leading edge detection sensor 51 detects, as a sheet leading edge detection signal, that the leading edge of the sheet P conveyed on the conveying surface 44 has passed below the sheet leading edge detection sensor 51. A paper leading edge detection signal from the paper leading edge detection sensor 51 is output to the control unit 100.

  A peeling member 5 is provided immediately downstream of the transport unit 40 in the transport direction. The peeling member 5 peels the paper P from the conveyance surface 44 by the leading end of the peeling member 5 entering between the paper P and the conveyance belt 43.

  The paper P peeled off from the transport surface 44 by the peeling member 5 is guided upward by the transport guides 31 and 32 and is transported upward while being sandwiched between the feed roller pairs 34 and 35, and is discharged to the paper discharge unit 6. One roller of each pair of feed rollers 34 and 35 is rotated by a feed motor 134 (see FIG. 6), and the other roller is a driven roller that rotates as the one roller rotates. Further, the feed motor 134 is controlled by the control unit 100. The conveyance guide 31 branches from the middle part thereof to the upstream side of the sheet reversing path 70.

  One drive roller of the pair of feed rollers 34 and 35 is a switchback roller, and rotates in a direction opposite to the rotation direction when the paper P sent from the transport unit 40 is discharged to the paper discharge unit 6. It is possible. The paper P peeled off from the transport surface 44 by the peeling member 5 is discharged to the paper discharge unit 6 as described above, or is guided by the transport guides 31 and 32 and sandwiched between the feed roller pairs 34 and 35. After being fed upward, one drive roller of the feed roller pair 34 and 35 rotates in the reverse direction, and is guided to the upstream side of the paper reversing path 70 where the conveyance guide 31 is branched. Sent to path 70.

  The sheet reversing path 70 extends in the vertical direction (vertical direction in FIG. 1), and reversing guides 71 and 74 curved from the middle portion thereof, reversing guides 72 and 73 extending in the conveying direction, and a reversing roller pair 75. , 76, 77, 78, 79. The sheet P guided by the transport guide 31 and fed downward while being sandwiched by the reverse roller pair 75 is guided by the reverse guides 71, 72, 73, 74 and is sandwiched by the reverse roller pairs 76, 77, 78, 79. It is conveyed while. One roller of the reversing roller pair 75, 76, 77, 78, 79 is a driven roller that is rotated by a reversing motor 135 (see FIG. 6), and the other roller is rotated as the one roller rotates. . The reversing motor 135 is controlled by the control unit 100.

  The paper P is fed to the transport unit 40 while being guided by the transport guides 26, 27, and 28 and being sandwiched between the feed roller pairs 21 and 22, with the other surface facing the inkjet head 2. That is, the sheet P transported from the sheet reversing path 70 to the transport unit 40 has a surface opposite to the sheet P transported from the paper feeder 23 to the transport unit 40 facing the inkjet head 2. It becomes possible to print on both sides.

  FIG. 2 is a plan view of the ink jet head as viewed from below. As shown in FIG. 2, each of the four inkjet heads 2 extends in the width direction (the left-right direction in FIG. 2) and is close to the transport direction (the direction perpendicular to the width direction and the up-down direction in FIG. 2). Are arranged side by side. That is, the ink jet printer 1 is a line type printer in which an ejection region extending in the width direction is formed.

  As shown in FIGS. 1 and 2, the inkjet head 2 has a head body 3 at the lower end thereof. The head body 3 has a rectangular parallelepiped shape that is elongated in the width direction. The bottom surface of the head body 3 is a discharge surface 3a that faces the transport surface 44, and a large number of nozzles 3b are arranged on the discharge surface 3a.

  As shown in FIG. 2, the plurality of nozzles 3b on each ejection surface 3a are arranged at equal intervals along the width direction to form a nozzle group 30, and four such nozzle groups 30 are arranged in the transport direction. They are arranged side by side. That is, the four nozzle groups 30 are arranged at different positions in the transport direction. The nozzle interval between nozzles 3b adjacent to each other in the width direction belonging to one nozzle group 30 is four times the diameter of the nozzle 3b.

  The four nozzle groups 30 belonging to one inkjet head 2 are arranged while being shifted to the right by the diameter of the nozzle 3b with respect to the width direction in order from the top of FIG. That is, the plurality of nozzles 3b belonging to each nozzle group 30 are arranged at different positions in the width direction. In this configuration, when ink is ejected at a desired ejection timing on one line along the width direction of the sheet P conveyed on the conveying surface 44 from the four nozzle groups 30 belonging to one inkjet head 2, the ink continues continuously without a gap. One printed line is recorded. Note that the print resolution in the width direction of the inkjet printer 1 in the present embodiment is 600 dpi. The arrangement of the nozzles 3b belonging to the four inkjet heads 2 is stored in a nozzle arrangement storage unit 111 described later as nozzle arrangement information.

  A print job is input to the inkjet printer 1 from a host computer (not shown) such as a PC. Then, based on the image data relating to the image to be formed on the paper P included in the print job, print data that is a collection of data indicating the discharge amount and discharge timing of each nozzle 3b is generated by the print data generation unit 109 described later. Is done. A drive signal based on this print data is applied to each nozzle 3b of the inkjet head 2, so that a desired amount of ink is delivered from each nozzle 3b at a desired ejection timing in accordance with the transport of the paper P by the transport unit 40. The desired image is recorded on the paper P.

  Here, for example, a plurality of sheets P stacked in the sheet feeding cassette 24 are shifted with respect to the width direction, so that the sheet P fed from the sheet feeding cassette 24 and conveyed on the conveying surface 44 is wide. There may be misalignment with respect to the direction. FIG. 3 is a diagram for explaining a sheet conveyance position. FIG. 4 is a plan view when an image is recorded on a sheet that is not misaligned.

  As shown in FIG. 3, the paper P fed from the paper feed cassette 24 and transported on the transport surface 44 is not displaced in the width direction, that is, the center of the inkjet head 2 in the width direction and the transported paper P. When the center in the width direction of the sheet P1 (indicated by the solid line in FIG. 3) overlaps in the transport direction, ink is ejected from the nozzle 3b in the ejection region 3c indicated by the oblique line of each inkjet head 2. An image is recorded in the hatched area Pa, which is the central area of the paper P1 (see FIG. 4). That is, as shown in FIG. 4, the hatched area Pa of the paper P1 is an image recording area, and the outer area of the hatched area Pa (area around the hatched area Pa) on the paper P1 is a blank area Pb. Yes.

  When there is no sheet misalignment, the widths X (hereinafter referred to as margin amounts) of the margin areas Pb on both sides in the width direction along the transport direction are uniform. In this case, the paper P is considered to be located at the reference position in the width direction. In the present embodiment, the margin amount is a constant value, and is a value set in advance in the printer. The margin amount may be set using a value (margin value) included in the print job input from the host computer, or may be a value obtained by adding the set value and the margin value. . That is, the margin amount may be a variable value.

  Further, as shown in FIG. 3, the paper P (paper P2 indicated by a two-dot chain line in FIG. 3) fed from the paper feed cassette 24 and transported on the transport surface 44 is shown in FIG. In the case where the position is shifted to the left side, if this print data is used, the image is recorded shifted to the right side of the paper P2. Further, when the positional deviation of the paper P2 is further large, the image protrudes from the paper P2, and a part of the image is not recorded on the paper P2.

  Further, when the paper P (paper P3 indicated by a two-dot chain line in FIG. 3) fed from the paper cassette 24 and transported on the transport surface 44 is displaced from the reference position to the right in FIG. However, the image may be recorded with the image shifted to the left of the paper P3 as in the case of the displacement of the left position, or a part of the image may not be recorded.

  Therefore, it is necessary to generate print data corresponding to the positional deviation of the paper P based on the image data. FIG. 5 is a diagram for explaining the ejection operation from the nozzle when the paper position is shifted. Specifically, as shown in FIG. 5, the print data is generated based on the image data so that the area for ejecting ink is shifted to the ejection area 3d indicated by diagonal lines corresponding to the positional deviation of the paper P.

  For example, when the paper P is shifted by 2 mm to the left in FIG. 5 from the reference position, print data based on the image data is recorded so that an image shifted by 2 mm to the left from the reference position is recorded on the paper P. Generate. If the arrangement of the nozzles 3b belonging to one inkjet head 2 is not shifted in the transport direction and is only one row along the width direction, it is given to the nozzle 3b when paying attention to one nozzle 3b. The drive signal is applied to the nozzle 3b located 2 mm to the left of the nozzle 3b. By performing such processing on all the nozzles 3b, that is, generating print data shifted to the left by 2 mm from the reference position, and applying a drive signal based on this print data to each nozzle 3b, the paper An image is recorded in the central area Pa of P.

  By the way, in the present embodiment, the plurality of nozzles 3b belonging to one ink jet head 2 is configured by arranging a plurality of nozzle rows along the width direction in the transport direction. That is, when the print data is generated based on the image data so that an image shifted 2 mm to the left is recorded on the paper P when the paper P is shifted 2 mm to the left in FIG. 5 from the reference position, In this embodiment, it is necessary to change the position of the nozzle 3b to be discharged and also change the discharge timing.

  For example, when attention is paid to a certain nozzle 3b, the drive signal given to the nozzle 3b is given to the nozzle 3b located 2 mm to the left of the nozzle 3b. At this time, since the nozzle 3b located 2 mm to the left is displaced in the transport direction, the ejection timing is also changed. Such processing is performed for all the nozzles 3b, that is, print data is generated by shifting the discharge timing to the left by 2 mm from the reference position, and a drive signal based on this print data is sent to each nozzle 3b. As a result, an image is recorded in the central area Pa of the paper P.

  However, the paper leading edge detection sensor 51 is disposed close to the inkjet head 2 in the transport direction, and the transport speed of the paper P is set high. Therefore, after the leading edge of the paper P is detected by the paper leading edge detection sensor 51, the transport position in the width direction of the paper P is detected by the paper position detection sensor 50, and print data is generated from the image data using this detection result. Therefore, if the ejection timing is also changed in addition to shifting the print data in the width direction by the displacement amount, the generation of the print data is not in time.

  Therefore, in the present embodiment, as will be described in detail later, for the target paper P using the transport position of the paper P that has been transported on the transport surface 44 immediately before the target paper P that is the target of image recording. Generate print data. Then, by applying a drive signal based on this print data to each inkjet head 2, an image with almost no displacement is recorded on the target paper P. This is expected that the transport position of the target paper P is substantially the same as the transport position of the paper P transported on the transport surface 44 before the target paper P. Therefore, print data is generated using the transport position of the paper P that is transported on the transport surface 44 before the target paper P, thereby generating print data that is highly likely to be suitable for the transport position of the target paper P at an early stage. can do. In particular, print data is generated using the transport position of the paper P that is transported on the transport surface 44 immediately before the target paper P, thereby generating print data that is more likely to be more suitable for the transport position of the target paper P. can do.

  Next, the control system of the inkjet printer 1 will be described with reference to FIG. FIG. 6 is a block diagram of the ink jet printer shown in FIG. As shown in FIG. 6, the inkjet printer 1 includes a control unit 100 that controls various operations. Specifically, the control unit 100 controls a print execution unit including the inkjet head 2, the transport unit 40, the paper position detection sensor 50, the paper leading edge detection sensor 51, and the like.

  The control unit 100 includes a CPU (Central Processing Unit) that is an arithmetic processing unit, a ROM (Read Only Memory) that stores a control program executed by the CPU and data used for the control program, and data when the program is executed. RAM (Random Access Memory) for temporary storage. These include a print job storage unit 101, a head control unit 102, a conveyance control unit 103, a paper leading edge acquisition unit 104, a paper position acquisition unit 105, a paper position storage unit 106, a print data generation unit 109, a nozzle array storage unit 111, and the like. Function.

  The print job storage unit 101 stores a print job input from a host computer (not shown) such as a PC. The print job includes image data relating to an image to be formed on the paper P.

  The head control unit 102 controls the head drive circuit 121 so that ink is ejected from each inkjet head 2 using the print data generated by the print data generation unit 109.

  The conveyance control unit 103 drives the sheet feeding motor 132 to rotate the sheet feeding roller 25 so that the uppermost sheet P in the sheet feeding cassette 24 is sent out along the conveyance guides 26, 27, and 28. 122, and the motor driver 124 is controlled so that the feed roller pair 21, 22 is rotated by driving the feed motor 134 to feed the paper P onto the transport belt 43. Further, the conveyance control unit 103 controls the motor driver 123 so that the belt roller 41 is rotated by driving the conveyance motor 133 and the sheet P is conveyed while being held on the conveyance surface 44 of the conveyance belt 43. Further, the conveyance control unit 103 controls the motor driver 124 so that the feed roller pair 34 and 35 is rotated by driving the feed motor 134 so that the paper P is discharged to the paper discharge unit 6. Further, the conveyance control unit 103 rotates the feed roller pair 34, 35 by driving the feed motor 134 and rotates the pair of reverse rollers 75, 76, 77, 78, 79 by driving the reverse motor 135. The motor drivers 124 and 125 are controlled so as to be sent again to the transport unit 40 via the paper reversing path 70.

  The paper leading edge acquisition unit 104 acquires a paper leading edge detection signal output from the paper leading edge detection sensor 51 and indicating that the leading edge of the paper P transported on the transporting surface 44 has passed below the paper leading edge detection sensor 51.

  The paper position acquisition unit 105 acquires a detection result that is output from the paper position detection sensor 50 and indicates the paper position in the width direction of the paper P that is transported on the transport surface 44.

  The paper position storage unit 106 stores the paper position in the width direction of the paper P acquired by the paper position acquisition unit 105.

  The print data generation unit 109 reads from the paper position storage unit 106 the transport position of the paper P that has been transported on the transport surface 44 immediately before the target paper P that is the target of image recording, and uses this transport position. Then, print data is generated based on the image data for the target paper P. At this time, the print data generation unit 109 generates print data while changing the ejection timing and the like so as to match the nozzle arrangement stored in the nozzle arrangement storage unit 111.

  The nozzle array storage unit 111 stores an array of nozzles 3b belonging to the four inkjet heads 2 as nozzle array information.

  Next, a series of printing operations by the ink jet printer in the first embodiment will be described. FIG. 7 is a flowchart showing a series of printing operations by the ink jet printer shown in FIG.

  First, when a print job is input from the host computer to the inkjet printer 1, the print job is stored in the print job storage unit 101. Then, as shown in FIG. 7, under the control of the conveyance control unit 103, the paper feed motor 132 is driven to rotate the paper feed roller 25, the paper P is sent out from the paper feed cassette 24, and the feed motor 134 is driven. Then, the pair of feed rollers 21 and 22 are rotated to feed the first sheet P (first print medium) to the upper transport unit 40 in FIG. 1 through the transport guides 26, 27 and 28 (S1). The sheet P sent to the transport unit 40 as the first sheet in a print job unit, which is a group of jobs for continuously recording images on a plurality of sheets P, is a sheet P to be transported first.

  Next, it is determined whether or not the sheet leading edge detection signal output from the sheet leading edge detection sensor 51 is acquired by the sheet leading edge acquiring unit 104 (S2). When the paper leading edge detection signal is not acquired (S2: No), the process waits until the leading edge of the paper P passes below the paper leading edge detection sensor 51. When the paper leading edge detection signal is acquired (S2: Yes), the paper position acquisition unit 105 acquires a detection signal indicating the transport position in the width direction of the paper P output from the paper position detection sensor 50 (S3). Then, the acquired transport position in the width direction of the first sheet P is stored in the sheet position storage unit 106 (S4).

  Thereafter, the conveyance control unit 103 controls the conveyance motor 133, the feed motor 134, and the reversal motor 135, and the sheet P conveyed on the conveyance surface 44 is rotated once through the sheet reversal path 70, and again to the conveyance unit 40. Send out (S5). During this time, even if the paper P opposes the inkjet head 2, no drive signal is applied to the inkjet head 2 and ink is not ejected from the nozzle 3b.

  In parallel with the process of S5, the transport position of the first (first) sheet P stored in the sheet position storage unit 106 is read by the print data generation unit 109 (S6), and the first sheet P is read. Is used to generate print data for the first and second sheets based on the first and second image data included in the print job stored in the print job storage unit 101. (S7). In this way, the sheet P conveyed on the conveying surface 44 is made to make one round via the sheet reversing path 70 and is sent to the conveying unit 40 again, thereby securing the time required for the print data for the first sheet P. be able to.

  Then, it is determined from the detection timing of S2 and the rotation amount of the belt roller 41 whether or not the paper P has been conveyed to a position facing the inkjet head 2 (S8). When the paper P is not transported to the position facing the inkjet head 2 (S8: No), it waits. When the paper P is conveyed to a position facing the inkjet head 2 (S8: Yes), by applying a drive signal based on the print data for the first sheet generated by the process of S7 to the inkjet head 2, Ink is ejected from each inkjet head 2 by the head controller 102, and printing on the first sheet P is started (S9). Then, the first sheet P that has been printed is discharged to the paper discharge unit 6, or in the case of double-sided printing, it goes around once again via the paper reversing path 70 and also on the opposite side. After the printing operation is performed, the paper is discharged to the paper discharge unit 6. In this way, the print data for the first sheet P can be generated using the detection result indicating its own transport position.

  Next, under the control of the conveyance control unit 103, the paper feed motor 132 is driven to rotate the paper feed roller 25, the paper P is sent out from the paper feed cassette 24, and the feed motor 134 is driven to feed the feed roller pair 21, 22, the second sheet P is sent out to the upper transport unit 40 in FIG. 1 through the transport guides 26, 27, and 28 (S10).

  Next, as with the first sheet P, it is determined whether the sheet leading edge detection signal output from the sheet leading edge detection sensor 51 is acquired by the sheet leading edge acquiring unit 104 (S11). When the paper leading edge detection signal is not acquired (S11: No), the process waits until the leading edge of the paper P passes below the paper leading edge detection sensor 51. When the paper leading edge detection signal is acquired (S11: Yes), the paper position acquisition unit 105 acquires a detection signal indicating the transport position in the width direction of the second sheet P output from the paper position detection sensor 50 ( S12). Then, the acquired transport position in the width direction of the second sheet P is stored in the sheet position storage unit 106 (S13).

  Then, based on the detection timing of S11 and the rotation amount of the belt roller 41, it is determined whether or not the paper P has been transported to a position facing the inkjet head 2 (S14). If the paper P has not been transported to the position facing the inkjet head 2 (S14: No), it waits. When the paper P is conveyed to a position facing the inkjet head 2 (S14: Yes), by applying a drive signal based on the print data for the second sheet generated by the process of S7 to the inkjet head 2, Ink is ejected from each inkjet head 2 by the head controller 102, and printing on the second sheet P is started (S15). Then, the second sheet P on which the desired printing on one side or both sides is completed is discharged to the paper discharge unit 6.

  In parallel with the processing of S14 and S15, the transport position of the second sheet P stored in the sheet position storage unit 106 is read by the print data generation unit 109 (S16), and printing is performed using this transport position. Based on the third image data included in the print job stored in the job storage unit 101, print data for the third sheet is generated (S17).

  Then, with reference to the print job storage unit 101, it is determined whether or not there is printing on the next sheet P (S18). If there is no printing on the next sheet P (S18: No), the printing operation is terminated. When there is printing on the next paper P (S18: Yes), the processing of S10 to S17 is executed, and the third paper is based on the print data for the third paper generated in the previous processing of S17. Print on P.

  As described above, in the inkjet printer 1 according to the first embodiment, the print data for the target paper P that is the target of image recording is detected indicating the transport position of the paper P transported before the target paper P. Generated using the result. At this time, the transport position of the target paper P is expected to be substantially the same as the transport position of the paper P transported before the target paper P. Therefore, print data that is highly likely to be suitable for the transport position of the target paper P can be generated at an early stage, and an image can be quickly recorded based on the print data.

  Further, the print data for the target paper P is generated using a detection result indicating the transport position of the paper P transported immediately before the target paper P, so that it is more suitable for the transport position of the target paper P. Print data with high possibility can be generated. In addition, it is easier to generate print data using the transport position of one sheet P than to generate using the detection result indicating the transport position of a plurality of sheets P.

  Furthermore, when a plurality of nozzles 3b belonging to one inkjet head 2 as in the first embodiment are arranged not only in the width direction but also in the transport direction, it takes time to generate print data. Therefore, the effect of the present invention becomes more remarkable.

Second Embodiment
Next, a second embodiment of the present invention will be described. FIG. 8 is a block diagram of an ink jet printer according to a modification.

  The ink jet printer 1 according to the present embodiment has the same mechanical configuration as the ink jet printer 1 according to the first embodiment, and only the print data generation process for the target paper P, which is a target for recording an image, is different. In addition, about the same thing as 1st Embodiment, the description shown with a same sign is abbreviate | omitted.

  As shown in FIG. 8, the control unit 200 includes a print job storage unit 101, a head control unit 102, a conveyance control unit 103, a paper leading edge acquisition unit 104, a paper position acquisition unit 105, a paper position storage unit 106, and a paper position estimation unit. 208, the print data generation unit 209, the nozzle array storage unit 111, and the like.

  The paper position estimation unit 208 transports the target paper P using the transport positions of the two papers P that have been transported on the transport surface 44 one and two times before the target paper P that is the target of image recording. Estimate the position. Specifically, the plurality of sheets P transported before the target sheet P do not have extremely different transport positions and are often transport positions based on a certain tendency. For example, the paper P transported two times before the target paper P is transported with a deviation of 0.2 mm from the reference position in the transport direction, and the paper P transported immediately before the target paper P is transported from the reference position. When the paper P is transported with a deviation of 0.4 mm in the direction, it is estimated that the paper P is linearly shifted with respect to the transport direction, and the target paper P is transported at a transport position shifted by 0.6 mm with respect to the transport direction from the reference position. It is estimated that

  The print data generation unit 209 generates print data based on the image data for the target paper P using the transport position of the target paper P estimated by the paper position estimation unit 208. At this time, the print data generation unit 209 generates print data while changing the ejection timing and the like so as to match the nozzle arrangement stored in the nozzle arrangement storage unit 111.

  Next, a series of printing operations by the ink jet printer in the second embodiment will be described. FIG. 9 is a flowchart showing a series of printing operations by the ink jet printer according to the modification.

  First, regarding the paper P sent to the transport unit 40 for the first (first) and second sheets of the print job input from the host computer to the inkjet printer 1, as in the first embodiment, S1 to S13. Is performed.

  Thereafter, it is determined whether or not the second sheet P has been transported to a position facing the inkjet head 2 (S14). In parallel with the start of printing on the second sheet P (S15), the print data The transport positions of the first and second sheets P stored in the sheet position storage unit 106 by the generation unit 209 are read (S16), and the sheet position estimation unit 208 uses these transport positions to read the third sheet P. The transport position of the paper P is estimated (S16_1). Based on the third image data included in the print job stored in the print job storage unit 101 using the transport position of the third sheet P estimated by the sheet position estimation unit 208, the print data The generating unit 209 generates print data for the third sheet (S17).

  Thereafter, when it is determined that the third sheet is printed (S18: Yes), the processing from S10 is performed, and an image is recorded on the third sheet P in S15. The fourth and subsequent sheets P are processed in the same manner as the third sheet P.

  According to this, the transport position of the third and subsequent sheets of paper P can be estimated more accurately, and print data that is more likely to be more suitable for the transport position of the third and subsequent sheets of paper P can be generated. Become.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various design changes can be made as long as they are described in the claims.

  In the first embodiment described above, print data for the target paper P is generated using the transport position of the paper P that has been transported on the transport surface 44 immediately before the target paper P that is the target of image recording. However, print data for a plurality of subsequent sheets P may be generated using the transport position of the first sheet P. According to this, only the first transport position of the paper P needs to be detected by the paper position detection sensor 50, and the number of detections by the paper position detection sensor 50 can be reduced.

  In the first and second embodiments described above, the paper P is rotated once through the paper reversing path 70 until the print data for the first paper P is generated (see FIG. 7 and processing S5 in FIG. 9, after the paper leading edge acquisition unit 104 acquires the transport position of the first paper P, the transport of the paper P is interrupted, and the print data generation unit 109 starts generating print data. The conveyance of the first sheet P may be resumed.

  Further, the ink jet printer in the first and second embodiments described above can perform double-sided printing, but the present invention can also be applied to an ink jet printer that does not have the paper reversing path 70 and only performs single-sided printing. . For example, when the inkjet printer can reciprocate the paper, the print data for the target paper P is generated during the first forward transport of the target paper P, and the drive is based on the print data generated during the backward transport. A signal may be applied to the inkjet head 2 to perform a printing operation. Alternatively, print data for the target paper P is generated at the time of the first forward transport of the target paper P, and the drive signal based on the generated print data is not given to the inkjet head 2 at the time of the backward transport, and the forward transport is performed again. Sometimes, a printing operation may be performed by applying a drive signal based on the print data to the inkjet head 2.

  In the second embodiment described above, the transport position of the target paper P is estimated from the transport position of the paper P that is transported one and two times before the target paper P. May be estimated from the paper P. Further, when the deviation tendency of the transport positions of the plurality of sheets P is not linear, the transport position of the target sheet P may be estimated using an appropriate estimation method. For example, the transport position obtained by averaging the transport positions of the paper P transported one and two times before the target paper P may be set as the transport position of the target paper P.

  Furthermore, in the first and second embodiments described above, the first sheet P is the first sheet P sent to the transport unit 40 in the print job unit, but a plurality of sheets P are stacked in the sheet feeding cassette 24. The first sheet P that is sent out to the transport unit 40 after being stored may be used as the first sheet P.

  The detection result detected by the paper position detection sensor 50 may be the actual transport position in the width direction of the paper P, or the amount of deviation from the reference position in the width direction of the paper P.

  Further, the present invention can be applied even when printing on the paper P with no margin.

  Furthermore, the present invention is applicable not only to the ink jet printer 1 having the ink jet head 2 but also to other types of printing apparatuses such as a printer having a thermal head that thermally transfers ink to the paper P.

  In addition, the control unit 100 may be provided not in the inkjet printer 1 but in a host computer such as a PC. That is, the acquisition of the detection result by the paper position acquisition unit and the generation of the print data using the detection result by the print data generation unit may be executed by the control unit in the host computer. In this case, the host computer corresponds to the control device in the present invention, and the host computer and the printer (print execution unit) correspond to the printing device in the present invention.

1 is a schematic configuration diagram of an inkjet printer according to a first embodiment of the present invention. It is a top view when an inkjet head is seen from the lower part. FIG. 6 is a diagram for explaining a sheet conveyance position. FIG. 6 is a plan view when an image is recorded on a sheet that is not misaligned. FIG. 10 is a diagram illustrating an ejection operation from a nozzle when a paper position is shifted. FIG. 2 is a block diagram of the ink jet printer shown in FIG. 1. 2 is a flowchart showing a series of printing operations by the inkjet printer shown in FIG. 1. It is a block diagram of the ink jet printer in a modification. It is a flowchart which shows a series of printing operation | movement by the inkjet printer in a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inkjet printer 2 Inkjet head 3b Nozzle 30 Nozzle group 40 Conveyance unit 50 Paper position detection sensor 51 Paper leading edge detection sensor 100, 200 Control part 104 Paper leading edge acquisition part 105 Paper position acquisition part 109,209 Print data preparation part 208 Paper position estimation Part

Claims (13)

A transport unit that transports a print medium in a first direction, a detection unit that detects a transport position of the print medium in a second direction intersecting the first direction, and a forming unit that forms an image on the print medium based on print data A control device that controls a print execution unit including:
An acquisition unit for acquiring a detection result indicating the transport position of the print medium from the detection unit;
The print data for forming an image on the target print medium is detected using a detection result indicating the transport position of at least one preceding print medium transported by the transport unit before the target print medium to be imaged. And a print data generation unit for generating the control data.   The control apparatus according to claim 1, wherein the at least one preceding print medium includes a print medium that the transport unit transports to a position before the target print medium. The at least one preceding print medium is one preceding print medium;
The print data generation unit generates the print data for the target print medium using only the detection result indicating the transport position of the one preceding print medium. The control device described in 1. The at least one preceding print medium is two or more preceding print media;
The print data generation unit includes an estimation unit that estimates a conveyance position of the target print medium using two or more detection results indicating the conveyance positions of the two or more preceding print media.
The control apparatus according to claim 1, wherein the print data generation unit generates the print data for the target print medium using the estimation result estimated by the estimation unit.   The control apparatus according to claim 4, wherein the two or more preceding print media include a print medium that the transport unit transports to the front and the second before the target print medium. In the case where images are continuously formed by the forming unit on a plurality of print media, the preceding print medium is a first print medium that the transport unit first transports among the plurality of print media,
The print data generation unit uses the first detection result indicating the transport position of the first print medium to print one or more prints other than the first print medium among the plurality of print media that are image formation targets. The control device according to claim 1, wherein the print data for a medium is generated.   The control apparatus according to claim 6, wherein the print data generation unit further generates first print data for forming an image on the first print medium, using the first detection result. . The forming unit includes a first nozzle group arranged along the second direction and a second nozzle group arranged along the second direction,
The first nozzle group and the second nozzle group are arranged at different positions with respect to the first direction,
Each nozzle of the first nozzle group and each nozzle of the second nozzle group are arranged at different positions with respect to the second direction,
The control device according to claim 1, wherein the print data generation unit generates the print data so as to match a nozzle arrangement of the forming unit. The control device according to any one of claims 1 to 8,
And a printing execution unit. A control device according to claim 7;
The printing execution unit,
The transport unit is
After the acquisition unit acquires the first detection result, the conveyance of the first print medium is interrupted,
The printing apparatus, wherein after the print data generation unit starts generating the first print data, the conveyance of the first print medium is resumed. A control device according to claim 7;
The printing execution unit,
The transport unit transports the first print medium a plurality of times so as to face the detection unit and the forming unit,
The detection unit detects the first detection result indicating the transport position of the first print medium in the first transport of the first print medium by the transport unit;
The forming unit prints an image on the first print medium based on the first print data generated using the first detection result in the second and subsequent conveyances of the first print medium by the conveyance unit. A printing apparatus characterized by forming. A transport unit that transports a print medium in a first direction, a detection unit that detects a transport position of the print medium in a second direction intersecting the first direction, and a forming unit that forms an image on the print medium based on print data And a control method of a control device that controls a print execution unit including:
An acquisition step of acquiring a detection result indicating the transport position of the print medium from the detection unit;
The print data for forming an image on the target print medium is detected using a detection result indicating the transport position of at least one preceding print medium transported by the transport unit before the target print medium to be imaged. A control method for a control apparatus, comprising: a print data generation step to generate. A transport unit that transports a print medium in a first direction, a detection unit that detects a transport position of the print medium in a second direction intersecting the first direction, and a forming unit that forms an image on the print medium based on print data A control program to be executed by a control device that controls a print execution unit including:
The control device;
Acquisition means for acquiring a detection result indicating the transport position of the print medium from the detection unit; and
The print data for forming an image on the target print medium is generated using a detection result indicating the transport position of at least one preceding print medium transported by the transport unit before the print medium targeted for image formation. A control program for a control apparatus, wherein the control program causes the print data generation means to function.

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