JP2011084044A - Printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent generation of banding etc. caused by switch back processing of preceding recording paper without changing a scanning time interval of a print head during printing process for recording paper, in a printer including the print head printing images on recording paper intermittently carried while scanning the recording paper in the main scanning direction and a switch back part executing the switch back processing with respect to printed recording paper (preceding recording paper). <P>SOLUTION: A print control part predicts whether or not the switch back processing is executed with respect to long recording paper in the switch back part during printing processing for the recording paper. When it is predicted that the switch back processing is executed (when determination in Step S5 is YES), generation of printing waiting time is predicted, and the scanning time interval of the print head is set to be a predetermined time interval Ts longer than a reference scanning time interval Tk so as not to generate the printing waiting time actually. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention discharges ink onto a recording sheet that is intermittently conveyed along the conveyance path, while ejecting ink while scanning in the main scanning direction orthogonal to the recording sheet conveyance direction. Belongs to a technical field related to a printer having a print head for printing.

  In this type of printer, there is known a printer in which a switchback device is provided in the middle of a conveyance path for conveying recording paper after printing in order to reduce the size of the apparatus and protect the printing surface.

  This switchback device includes, for example, a pair of rollers capable of normal rotation and reverse rotation provided in the middle of a conveyance path as shown in Patent Document 1, printed by a print head, and conveyed from the print head side. After the paper is drawn by the pair of rollers, it is configured to change the transport direction of the recording paper (execute switchback processing) by sending it out to the discharge port side.

JP 2006-76672 A

  By the way, in the printer shown in the above-mentioned patent document 1, there is a case where a preceding recording paper switchback process (post-processing) is executed in the switchback device during the printing process on the recording paper by the print head. In this case, for example, if the size of the preceding recording sheet is a long size, the time required for the subsequent processing becomes long and a printing waiting time (time for temporarily interrupting the printing process) occurs. . As a result, there is a problem that banding (vertical streak) occurs at the boundary position of the print image before and after the printing process is interrupted, and the image quality of the print image is deteriorated.

  The present invention has been made in view of such a point, and an object of the present invention is to be orthogonal to the recording paper conveyance direction when the conveyance is stopped toward the recording paper that is intermittently conveyed along the conveyance path. In a printer provided with a print head that prints an image on the recording paper by discharging ink while scanning in the main scanning direction and a post-processing device that executes post-processing on the recording paper that has been printed, The purpose of this is to prevent the occurrence of printing defects such as banding due to post-processing of recording paper.

  In order to achieve the above object, according to the present invention, when a printing process on a recording sheet is executed by scanning a print head at a preset reference scanning time interval, a post-processing device performs the printing process. When it is predicted whether or not a printing waiting time will be generated by executing post-processing of the preceding recording sheet, and when it is predicted that a printing waiting time will occur, the print head scanning time interval is set as the printing waiting time. Is set to be longer than the reference scanning time interval so as not to actually occur.

  Specifically, in the first aspect of the invention, ink is ejected toward the recording paper intermittently conveyed along the conveyance path while scanning in the main scanning direction orthogonal to the recording paper conveyance direction when the conveyance is stopped. A print head that prints an image on the recording paper, a post-processing device that is disposed downstream of the print head and that performs post-processing on the recording paper that has been printed by the print head, and Target printers with

  When the print processing is performed on the recording paper by causing the print head to scan at a preset reference scanning time interval, the recording paper that has been subjected to printing processing in the post-processing device during the printing processing is performed. Prediction means for predicting whether a print waiting time will occur due to post-processing, setting means for setting a scan time interval of the print head based on a prediction result by the prediction means, and the setting Printing control means for executing a printing process on the recording paper by scanning the print head at a scanning time interval set by the means, and the setting means generates the printing waiting time by the prediction means. If it is predicted that the print head will not perform, the print head scan time interval is set to the reference scan time interval, while the print wait time is predicted to occur. Is the case were the scan time interval of the print head, such that the print waiting time does not actually occur, it is assumed that is configured to set a longer predetermined time interval than the reference scan time interval.

  According to this, when the print processing on the recording paper is executed by scanning the print head at a preset reference scanning time interval, the recording paper that has been printed in the post-processing device during the printing processing. On the other hand, it is predicted by the prediction means whether or not a printing waiting time is generated by performing post-processing. If the predicting unit predicts that the printing waiting time will occur, the setting unit will set the scanning time interval of the print head to the reference scanning time so that the printing waiting time does not occur when the print head performs the actual printing process. A predetermined time interval longer than the interval is set.

  Therefore, it is possible to prevent the printing waiting time from occurring due to the post-processing of the preceding recording paper during the printing process on the recording paper by the print head, and consequently, banding occurs in the printed image. Can be prevented.

  On the other hand, when it is predicted by the predicting means that no print waiting time will occur, the setting means sets the scan time interval of the print head to the reference scan time interval.

  Therefore, the print processing time can be shortened by setting the reference scanning time interval to, for example, the lower limit value of the range in which the image quality of the printed image can be maintained.

  In this specification, the “scan time interval” is the time from the end of the previous scan to the start of the next scan, and waits for the print head between the previous scan and the next scan. It is time to let.

  According to a second aspect of the present invention, in the first aspect of the present invention, the predicting unit predicts whether or not the print waiting time occurs before performing the printing process on the recording paper by the print head. The printing waiting time is generated by the prediction unit when the printing waiting time is predicted to be generated by the prediction unit, and the printing waiting time is generated by the prediction unit. Then, when it is predicted, it further comprises a scanning number estimating means for estimating the total number of scanning times of the print head required from the start to the end of the printing process on the recording paper by the print head, the setting means, If the printing waiting time is predicted to be generated by the prediction unit, the scanning time interval of the print head is set to the predetermined time interval satisfying the relationship of the following equation: It is assumed to be configured so that.

Ts = Tk + Tw / (N-1)
Tk: the reference scanning time interval Ts: the predetermined time interval Tw: the length of the printing waiting time N: the total number of scanning times of the print head According to this, the printing waiting time expected to be generated by the predicting means is printed. It is possible to evenly allocate the waiting time (= scanning time interval) between each scan of the head.

  Thereby, it is possible to reliably prevent the occurrence of the printing waiting time without making the scanning time interval of the print head H longer than necessary. Therefore, it is possible to improve the image quality of the printed image as much as possible while shortening the printing processing time.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the post-processing device is disposed in a transport path downstream of the print head and receives the recording paper from the leading end side. It is assumed that a switchback process for discharging from the rear end side after changing the transport direction is executed.

  According to a fourth aspect of the present invention, in the third aspect of the invention, the predicting unit performs the printing process on the recording paper by causing the print head to scan at a preset reference scanning time interval. During the printing process, the post-processing device predicts whether or not the switchback process is executed for a recording sheet having a predetermined length or more, and if it is predicted to execute, the printing waiting time occurs. It is assumed to be configured to be predicted.

  According to these third and fourth aspects of the invention, during the printing process on the recording paper, the post-processing device executes the switchback process on the long recording paper (recording paper of a predetermined size or more). As a result, it is possible to prevent the printing waiting time from occurring.

  As described above, according to the printer of the present invention, when the printing process on the recording paper is executed by scanning the print head at a preset reference scanning time interval, the post-processing device performs the printing process. When it is predicted whether or not a printing waiting time will occur due to the post-processing of the preceding recording paper, and when it is predicted that the printing waiting time will occur, the scan time interval of the print head is set to Since the printing waiting time is set to be longer than the reference scanning time interval so that the printing waiting time does not actually occur, the printing process is caused by the post-processing of the preceding recording sheet during the printing process on the recording sheet. It is possible to prevent the occurrence of a printing waiting time that interrupts the printing, and thus it is possible to prevent the occurrence of image defects such as banding in the printed image.

FIG. 2 is a perspective view illustrating an appearance of the printer according to the embodiment of the present invention, viewed from an oblique right side on the front side of printing. It is the schematic seen from the printer right side which shows the internal structure of a printer. It is the figure seen from the printer left side which shows the structure of a printing part and a cap part. It is the side view seen from the printer right side which shows the opening-and-closing shutter mechanism when the shutter roller of a magazine opening part is in a closed state. It is the side view seen from the printer right side which shows the opening-and-closing shutter mechanism when the shutter roller of a magazine opening part is in an open state. FIG. 6 is a sectional view taken along line VI-VI in FIG. 2. FIG. 2 is a schematic diagram illustrating a configuration of a guide unit, in which (a) illustrates a state in which a central guide member is in a use position in order to convey a narrow size recording paper, and (b) illustrates a wide size recording paper. In order to convey, the center guide member is in a non-use position. 3 is a cross-sectional view showing a configuration of a recording paper holding unit D. FIG. It is a top view which shows the structure of the platen of a printing part. It is a schematic plan view showing the configuration of a compartment provided on the lower side of the platen, where (a) shows a state in which a narrow-size recording paper passes over the platen, and (b) shows a wide-size recording paper. The state where the recording paper is passing over the platen is shown. It is sectional drawing which shows the ink absorption member accommodated in the recessed part of the platen. FIG. 6 is a schematic diagram illustrating a state in which a switchback roller pair of a switchback unit receives a recording sheet conveyed from a pair of conveyance rollers after cutting. FIG. 13 is a view corresponding to FIG. 12 showing a state in which the driven rollers of the switchback roller pair are switched to the second position. FIG. 2 is a block diagram illustrating a configuration of a printer control system. 6 is a flowchart illustrating processing for setting a scan time interval of a print head in a print control unit.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view showing a partially omitted configuration of an ink jet printer A according to an embodiment of the present invention. The printer A is used in a photo print system. For example, the printer A obtains image data and order information and performs necessary correction processing from a reception block 200 (see FIG. 14) via a communication cable. The transmitted image data is configured to be printed on the recording paper P based on the order information.

-Overall configuration-
FIG. 2 is a schematic diagram illustrating the configuration of the printer A. As shown in FIG. 2, the printer (inkjet printing apparatus) A includes a recording paper storage unit 1 provided at a lower part of the printer for storing a roll-shaped recording paper P, and is pulled out from the recording paper storage unit 1. And a printing unit 2 provided on the upper part of the printer so as to perform recording printing of image data on the recording paper P.

  In the upper part of the printer A, on the downstream side of conveyance of the printing unit 2, a cutter unit 4 that cuts the recording paper P after printing into a predetermined print size, and a printing surface by switching back the recording paper P after cutting. A switchback section 5 for changing the orientation of the recording paper, a back surface printing unit 6 for printing a serial number etc. on the back surface of the recording paper P, a drying unit 7 for drying the printing surface of the recording paper P, and wound in a roll shape A decurling unit 8 for removing the curled recording paper P and discharging it, and a conveyor for distributing the discharged recording paper P to one side of the printer in the left-right direction of the printer (direction perpendicular to the paper surface of FIG. 2). The apparatus 150, the large-size tray 104 (see FIG. 1) for receiving the large-sized recording paper P such as B5 size and A4 size, and the photographic-size recording paper P such as the L plate are received. Stacking device 210 for integrating each over da is disposed. The printer A is covered with a casing 3 except for the large-size tray 104 and the stacking device 210, and a moving caster 3 a is attached to the lower surface of the casing 3.

  The recording paper storage unit 1 is positioned almost directly below the printing unit 2 and can store two magazines M1 and M2 for storing the recording paper P. The magazines M1 and M2 are arranged side by side in the vertical direction, and a roll-shaped recording sheet P is accommodated in the magazines M1 and M2 while being held by the winding core R. In the present embodiment, a roll-shaped recording paper P having a wide size (for example, a width exceeding 12 inches) is accommodated in the magazine M1, and a narrow size (for example, a width of 12 inches or less) is accommodated in the magazine M2. ) Roll-shaped recording paper P is accommodated in two rows in the axial direction.

  In this embodiment, the printer A includes the manual feed unit 9, which enables printing on the sheet-like recording paper P supplied from the manual feed unit 9.

  The printing unit 2 ejects ink onto the recording paper P, thereby forming a print head H that forms an image composed of a large number of ink dots, and the recording paper P provided below the printing head H is sucked to the printing position. And a recording paper holding unit D for holding the recording paper.

  The print head H is configured to be movable along a guide rail 10 (see FIG. 3) extending in the main scanning direction X. Specifically, the rotational force of the drive motor 11 is transmitted to the drive belt 12 via the pulley 46, and the print head H moves in the main scanning direction X according to the rotation amount of the drive belt 12.

  Further, the print head H has two head units 13 and 13 arranged in the sub-scanning direction. By ejecting ink from the ink ejection nozzles provided in these head units 13 and 13, the recording paper is recorded. A predetermined image, character, or the like can be printed on P.

  Seven ink cartridges (not shown) in which inks having different hues are sealed are detachably accommodated in the lower portions on the left and right sides of the inkjet printer A, respectively. Accordingly, by attaching or detaching these ink cartridges from the case, it is possible to exchange used or used ones with new ones.

  Each of these ink cartridges includes yellow (Y), magenta (M), cyan (C), black (K), red (R), violet (V), and clear (CL: transparent) inks. Is enclosed.

-Recording paper transport mechanism-
As shown in FIG. 2, the printer A is provided with a recording paper storage unit 1 for storing a long recording paper P wound in a roll shape at the bottom of the printer, while the recording paper P from the recording paper storage unit 1 is provided. A transport mechanism accommodating portion 20 is provided in the upper part of the printer. The transport mechanism accommodating portion 20 accommodates a recording paper transport mechanism that performs various processes such as image printing and cutting while pulling out the paper and transporting it along a predetermined transport path.

  In this embodiment, in addition to supplying the recording paper P from the recording paper storage unit 1, a manual feed configured so that a predetermined size of recording paper can be supplied from the manual feed tray 102 via the manual feed roller pair 27. Although the unit 9 is also provided, the case where the recording paper P is supplied mainly from the recording paper storage unit 1 will be described below. In the following description, the side on which the manual feed tray 102 is provided is defined as the front side of the printer, and the opposite side is defined as the rear side of the printer. Further, the left side when viewed from the front side of the printer is defined as the left side of the printer, and the right side is defined as the right side of the printer.

As described above, two magazines M1 and M2 are stored in the recording paper storage unit 1.
When printing on a wide-sized recording sheet P, the recording sheet P stored in the magazine M1 is pulled out from the front end of the recording sheet P and guided out by the pair of magazine rollers 22 while being guided by the guide roller 21. It is. The recording paper P sent out of the magazine passes through a branch portion 23b on the rear side of the printer of the guide portion 23 that branches into two on the upstream side, and is disposed opposite to the supply roller 24 and the supply roller 24 that form a recording paper transport mechanism. It is sandwiched between the pair of press rollers 24a and 24b.

  The recording paper P conveyed by the rotation of the supply roller 24 is supplied to the printing unit 2 on the downstream side of the conveyance, and an image is printed on the recording paper P by the print head H.

  When printing on a narrow-sized recording sheet P, both or one of the two roll-shaped recording sheets P accommodated in the magazine M2 is pulled out from the leading end, and the pulled-out recording sheet P is While being guided by the guide roller 21, it is fed out of the magazine by the magazine roller pair 22. The recording paper P sent out of the magazine passes through the branch portion 23a on the front side of the printer of the guide portion 23 and is sandwiched between the supply roller 24 and the pair of pressure-bonding rollers 24a and 24b. The print head H prints an image on the recording paper P.

  The guide portion 23 guides the leading end portion of the recording paper P so as not to deviate from the conveyance path, and positions the recording paper P in the width direction.

  The printed recording paper P is sent to the cutter unit 4 by the post-printing conveyance roller pair 25 and cut into a predetermined print size. The cut recording paper P is delivered to the switchback unit 5 by the three post-cutting conveyance roller pairs 26. These three post-cutting conveying roller pairs 26 are prepared for receiving the recording paper P that is transported next after the recording paper P is delivered to the switchback unit 5 and then simultaneously released from pressure bonding.

  In the switchback unit 5, the cut recording paper P is received from the leading end side and drawn by the switchback roller pair 173, and then the conveyance direction is changed from the horizontal direction to the vertical direction (from the left and right direction in FIG. 2 to the up and down direction). Then, discharge from the rear end side.

  The recording paper P discharged from the switchback unit 5 is sent to the back surface printing unit 6 by the supply roller pair 175, and the reference number and the like are printed on the back surface of the recording paper P, and then conveyed to the drying unit 7.

  In the drying unit 7, the printing surface P is dried while being transported by the transport roller pair 28. The recording paper P that has been dried is sent to the decurling unit 8 by the conveying roller pair 29.

  In the decurling unit 8, in order to remove the curling of the recording paper P wound in a roll shape, the decurling roller 82 is moved between the driving conveying roller 81 while the recording conveying P is sandwiched and conveyed by the driving conveying roller 81 and the decurling roller 82. It moves to the clockwise direction of FIG. 2 along an outer peripheral surface. As a result, the recording paper P is decurled while being bent in a direction opposite to the curling direction, and is discharged from the discharge port 90 onto the conveying belt 151 of the conveyor device 150.

-Details of each component-
Hereinafter, each component of the printer A will be described in detail. The recording paper storage unit 1 is provided with a slide base 30 on which the magazines M1 and M2 are placed. The slide table 30 is configured to be slidable in the front-rear direction of the printer by linear guides (not shown) provided on the left and right sides in the housing 3 and extending in the front-rear direction of the printer. Thus, the magazines M1 and M2 can be taken in and out of the housing 3 by sliding the slide table 30. The front surface of the slide table 30 is covered with a door member 31 that forms a part of the housing 3 and can be opened and closed, and the recording paper P can be replaced by opening the door member 31. It is like that.

  In the following description, the left side of FIG. 2 (showing a state where magazines M1 and M2 are set in the recording paper storage unit 1) is defined as the magazine front side, and the right side is defined as the magazine rear side. Further, a direction perpendicular to the paper surface of FIG. 2 is defined as a magazine length direction (a direction matching the printer left-right direction).

  The magazines M1 and M2 are substantially hermetically sealed box-type containers configured to be portable. An opening 111 for pulling out the recording paper P stored in the magazines M1 and M2 to the outside of the magazines M1 and M2 is formed at the front end of the magazines M1 and M2. The opening 111 has a substantially rectangular shape extending in the magazine length direction. The magazines M1 and M2 are provided with an opening / closing shutter mechanism 120 for opening and closing the opening 111.

  As shown in FIGS. 4 and 5, the opening / closing shutter mechanism 120 includes a guide plate 114 that guides the recording paper P drawn from the winding core R to the opening 111, a state in which the recording sheet P is pressed against the guide plate 114, and pressure bonding. A shutter roller 115 capable of switching between the released state and a cam mechanism 116 for driving the shutter roller 115 is provided.

  The shutter roller 115 extends in the magazine length direction along the openings 111 of the magazines M1 and M2. A small-diameter shaft portion 115 a having a smaller diameter than the shutter roller 115 is formed at both axial ends of the shutter roller 115. The shutter roller 115 is supported by engaging the small-diameter shaft portion 115a with long holes 120c formed on both side walls in the length direction of the magazines M1 and M2. The small-diameter shaft portion 115a is constantly urged toward the guide plate 114 by an urging spring (not shown) and is in contact with the movable plate 117 constituting a part of the cam mechanism 116.

  The cam mechanism 116 includes the movable plate 117 and an eccentric cam 118 driven by a motor (not shown). In addition, the code | symbol 118a in the figure has shown the output shaft of the motor.

  The movable plate 117 is formed with two long holes 117a extending in the longitudinal direction of the magazine. The movable plate 117 is slidable in the longitudinal direction of the magazine by engaging the two long holes 117a with the two fixed shafts 117b protruding from the side surface of the magazine.

  A substantially rectangular hole 117c is formed at the end of the movable plate 117 on the rear side of the magazine. The inner peripheral surface of the hole 117c constitutes a contact surface that contacts the cam surface of the eccentric cam 118.

  The eccentric cam 118 is attached eccentrically with respect to the output shaft 118a of the motor. A proximity sensor 119 for detecting the origin of the motor is provided on the rear side of the magazine of the motor, and a rod-shaped detection dog 118b is attached to the output shaft 118a of the motor.

  The operation of the open / close shutter mechanism 120 configured as described above will be specifically described. FIG. 4 shows a state in which the shutter roller 115 is pressed against the guide plate 114. In this state, the eccentric cam 118 is located on the rear side of the magazine with respect to the output shaft 118a of the motor. When the motor is driven in the clockwise direction in FIG. 4, the eccentric cam 118 rotates in the clockwise direction together with the output shaft 118a of the motor, and moves to the magazine front side with respect to the output shaft 118a. As a result, the cam contact surface of the movable plate 117 is pressed to the magazine front side by the eccentric cam 118, and the movable plate 117 slides to the magazine front side. Thereby, the movable plate 117 moves the small diameter shaft portion 115a to the front side of the magazine against the biasing force of the biasing spring. Accordingly, the shutter roller 115 is also moved to the front side of the magazine, and a gap is formed between the guide plate 114 and the shutter roller 115, so that the opening 111 is opened.

  As described above, in this embodiment, since the motor-driven opening / closing shutter mechanism 120 is provided in the openings 111 of the magazines M1 and M2, the shutter roller 115 is forcibly driven by the motor when the printer A is not operated. Can be closed. Accordingly, the magazines M1 and M2 are left for a long period of time with the shutter roller 115 opened, so that the air in the magazines M1 and M2 is prevented from drying, and the recording paper P in the magazines M1 and M2 is removed. It can be protected from cracks and the like.

  The magazine roller pair 22 provided in the recording paper storage chambers S1 and S2 inside the magazines M1 and M2 is a pressure-bonding roller pair including a magazine driving roller 32 and a magazine driven roller 33.

  Here, in the magazine M1 in which the wide-sized recording paper P is accommodated, both the magazine driving roller 32 and the magazine driven roller 33 are configured by a single cylindrical roller.

  On the other hand, in the magazine M2 in which the narrow size recording paper P is accommodated, the magazine driven roller 33 is constituted by a single cylindrical roller, whereas the magazine driving roller 32 has a left divided roller 32a and a right divided roller. Two cylindrical rollers with the roller 32b are arranged in series (coaxially). The left and right divided rollers 32 a and 32 b constituting the magazine drive roller 32 are connected to left and right motors 91 disposed in the housing 3 and can be driven independently. One of the left and right motors 91, 91 (in this embodiment, the left drive motor 91) is also used as a drive source for the magazine drive roller 32 provided in the magazine M1.

  The left and right divided rollers 32a and 32b constituting the magazine drive roller 32 in the magazine M2 are set to a length corresponding to the width of each recording paper P. When both the left and right recording papers P stored in the magazine M2 are pulled out, both the left and right divided rollers 32a and 32b are driven by the motor 91. Further, when pulling out only one of the two rows of recording paper P accommodated in the magazine M2, only the divided rollers 32a and 32b corresponding to the one recording paper P are driven by the motor 91. When pulling out the wide-sized recording paper P stored in the magazine M1, the magazine driving roller 32 disposed in the magazine M1 is driven by the left motor 91.

  Here, in FIG. 6, the left and right divided rollers 32 a and 32 b are directly connected to the motor 91, but actually the motor 91 is fixed to the motor mounting base in the housing 3, and the magazine M <b> 1 is When set at a predetermined position, the left and right motors 91 are connected to the respective divided rollers 32a and 32b via gear mechanisms (not shown). The left motor 91 is also coupled to the magazine drive roller 32 in the magazine M2 when the magazine M2 is set at a predetermined position.

  The supply roller 24 is composed of a single cylindrical roller. The supply roller 24 is driven by a motor (not shown) different from the motor 91, and rotates in the forward direction to pull out the recording paper P from the recording paper storage unit 1 and transport it to the printing unit 2 side. The rotation in the reverse direction to return to the recording paper storage unit 1 can be switched. As a result, after the printed portion of the recording paper P is cut into a predetermined size by the cutter unit 4 on the downstream side of the supply roller 24, the long recording paper P is returned to the upstream side and the top of the recording paper P is returned. When printing from the beginning, or when the recording paper P is supplied from the manual feed unit 9 instead of the long recording paper P, the long recording paper P can be returned into the recording paper storage unit 1. ing.

  As described above, in this embodiment, the magazine drive roller 32 in the magazine M2 is composed of the two divided rollers 32a and 32b, and each of the divided rollers 32a and 32b can be independently driven by different drive motors 91. . Therefore, as described above, by controlling the driving of the left and right divided rollers 32a and 32b constituting the magazine driving roller 32, only the necessary recording paper P among the recording papers P in the magazine M2 is selectively pulled out. Can do. A motor (drive motor 91 or the like) that drives each of the rollers 24, 32a, and 32b is controlled by a conveyance control unit 202 described later.

  By the way, in the present embodiment, the magazine drive roller 32 in the magazine M2 is divided, but even if the supply roller 24 is divided, the left and right divided rollers are separated as in the present embodiment. By selectively driving, only the necessary recording paper P can be pulled out. However, since the supply roller 24 is required to have higher conveyance accuracy than the magazine drive roller 32, the left and right divided rollers are synchronized with high accuracy when two rows of narrow-size recording paper P are simultaneously conveyed. There is a need. For this reason, it is necessary to improve the accuracy of the motor that drives each of the divided rollers, which increases the cost. On the other hand, the magazine drive roller 32 has a lower conveyance accuracy than the supply roller 24. Therefore, if the magazine drive roller 32 is divided as in the present embodiment, a narrow size recording is performed. Even when two sheets of paper P are transported simultaneously, the synchronization accuracy of the two divided rollers 32a and 32b can be set relatively low, and the motor 91 that drives the divided rollers 32a and 32b can be made highly accurate. The required conveyance accuracy can be sufficiently ensured.

  As shown in FIG. 7, the guide unit 23 includes a pair of left and right guide members 41 and 42 arranged at a predetermined interval (interval corresponding to the width of the wide-size recording paper P) in the left-right direction of the printer, and both guide members. And a central guide member 43 disposed between 41 and 42.

  The left and right guide members 41 and 42 have a U-shaped cross section, and are disposed such that the U-shaped opening sides face each other. The left and right guide members 41 and 42 are disposed so as to be bilaterally symmetric with respect to the printer center surface 95 passing through the center of the platen 45 in the main scanning direction X. When printing on a wide-sized recording sheet P, the both ends in the width direction of the recording sheet P are conveyed while being inserted into the grooves 41a and 42a of the guide members 41 and 42, respectively. As a result, the position of the recording paper P in the width direction is restricted, and the recording paper P can be prevented from shifting in the width direction from a predetermined transport path.

  The central guide member 43 is supported by a feed mechanism (not shown) (for example, a ball screw mechanism), and is used on the same surface as the transport surface of the recording paper P (position shown in FIG. 7A). It is configured to be movable between a non-use position (position shown in FIG. 7B) located on the front side of the printer with respect to the conveyance surface of the recording paper P.

  The central guide member 43 is formed of a substantially rectangular parallelepiped member, and a surface passing through the center in the width direction of the central guide member 43 coincides with the printer central surface 95. The central guide member 43 has a substantially H-shaped cross-section perpendicular to the longitudinal direction, and U-shaped groove portions 43 a are formed on both left and right side surfaces of the central guide member 43.

  When printing on the narrow-sized recording paper P, the central guide member 43 is moved to the use position by the feeding mechanism. As a result, among the both ends in the width direction of the recording paper P, the end portion located on the printer central surface 95 side is conveyed while being inserted into the groove portion 43 a of the central guide member 43. During this conveyance, the end portion of the recording paper P located on the side opposite to the printer central surface 95 side is guided by the left and right guide members 41 and 42. As a result, the position in the width direction of the narrow size recording paper P can be regulated. On the other hand, when printing on a wide size recording paper P, the central guide member 43 is moved to the non-use position by the feeding mechanism, and the width direction position of the recording paper P is the left and right guide members 41 and 42. Will be regulated only by.

  As shown in FIG. 3, the printing unit 2 includes two guide rails 10 that guide the print head H in the main scanning direction X (direction perpendicular to the conveyance direction (sub-scanning direction Y) of the recording paper P). A drive belt 12 wound around two pulleys 46 (only one is shown in FIG. 3) and reciprocatingly moving the print head H along the guide rail 10 and a drive motor 11 driving the pulley 46 to rotate. A recording paper holding portion D that is sucked and held at a position where printing can be performed by the print head H, and a pressure-bonding post-printing conveyance roller pair 25 disposed on the downstream side of the recording paper holding portion D. I have. Here, the main scanning direction X corresponds to the left-right direction of the printer (also the width direction of the recording paper P), and the sub-scanning direction Y corresponds to the front-back direction of the printer (also the longitudinal direction of the recording paper P).

  A plurality of ink discharge nozzles are provided on the bottom surface of the print head H (the surface facing a recording paper holding portion D described later) so as to form a row in the sub-scanning direction Y (recording paper transport direction). A head unit 13 is provided, and these two head units 13 are arranged at intervals in the sub-scanning direction Y.

  Each of the head units 13 has the same configuration, and is composed of a plurality of nozzle arrays that eject the inks arranged in the main scanning direction X. In each nozzle array, ink discharge nozzles are arranged in a row in the sub-scanning direction Y. Accordingly, each head unit 13 is configured to be able to form a color image by itself.

  Here, the configuration of each head unit 13 is not particularly limited, but each head unit 13 in the present embodiment is provided for each ink discharge nozzle and has a volume of a pressure chamber filled with ink. In general, the piezo method is a method in which ink is ejected by varying a piezoelectric element (piezo element).

  The number of head units 13 is not necessarily two, and may be one or three or more.

  The recording paper P on the recording paper holding section D is conveyed intermittently (stepwise) in the sub-scanning direction Y by a supply roller 24 provided on the upstream side of the recording paper holding section D at a constant unit conveyance amount. At each stop of the recording paper P during the intermittent conveyance, the print head H is scanned once in the main scanning direction (one-way operation or one-time operation), and at each position in the main scanning direction during this scanning, Ink is ejected from the ink ejection nozzles of the head unit 13. That is, after one scan of the print head H, the recording paper P is transported by the unit transport amount, and then the print head H is scanned once again, and this operation is repeated to print a desired image on the recording paper P. Will be.

  Further, a standby position for the print head H to wait when printing is not being performed is set at a position outside the print area in the main scanning direction X of the print head H. 52 is provided.

  The cap portion 52 is in close contact with the head unit 13 of the print head H to prevent ink thickening when the print head H is not used. Suction caps 14 arranged in a row are provided. Then, the cap unit 52 moves up and down between a position in close contact with the bottom surface of the print head H and a position away from the bottom surface of the print head H.

  A bearing holder portion 56 having a guide hole 55 is formed at the rear end portion of the print head H, and a plate-like guide plate 57 extending in the main scanning direction is formed at the front end portion of the printer. Yes. The print head H is supported by placing the guide plate 57 on the guide rail 10 on the front side of the printer with the guide rail 10 on the rear side of the printer fitted in the guide hole 55 of the bearing holder portion 56. ing. According to this configuration, when a paper jam or the like occurs, the jammed paper can be easily removed by rotating the print head H upward with the guide rail 10 on the rear side of the printer as a fulcrum.

  On the other hand, at the standby position of the print head H, there is provided a mechanism for preventing the head H from floating when the cap portion 52 is in close contact with the lower surface of the print head H. This mechanism includes a pressing roller 54 rotatably supported by a fixing member 53, and the front side of the printer of the print head H is sandwiched between the pressing roller 54 and the guide rail 10. The movement of the end of the upper and lower sides is restricted. This prevents the head H from being lifted when the cap portion 52 is in close contact with the print head H, thereby reliably preventing ink thickening.

  As shown in FIGS. 8 and 9, the recording paper holding portion D has a plurality of suction holes 60 opened on the surface (upper surface) corresponding to the print area of the print head H, and corresponds to the flushing area. The platen 45 in which the flushing hole 61 is formed, the space 62 provided below the print area of the print head H in the platen 45 and communicating with the suction hole 60, and the suction hole 60 is formed by sucking and exhausting the air in the space 62. And a suction fan (not shown) that generates a negative pressure on the surface of the platen 45 and sucks and holds the recording paper P on the surface of the platen 45.

  Below the space 62, there is formed a device housing space 65 in which a suction fan and an opening / closing mechanism 64 described later are housed.

  The space 62 is divided into a plurality (six in this embodiment) by partitions arranged in the main scanning direction X (see FIG. 10). A communication hole 67 that communicates with the instrument housing space 65 is formed on the lower surface of each compartment 66. An opening / closing plate 67 a is provided in each communication hole 67 of each compartment 66. Each opening / closing plate 67a is configured to be able to open / close each communication hole 67 by rotating around a support shaft 68 extending in the main scanning direction X.

  The opening / closing plate 67a is urged around the support shaft 68 in the clockwise direction in FIG. 8 by an urging spring (not shown), and is opened / closed by an opening / closing mechanism 64 accommodated in the device accommodation space 65. The opening / closing mechanism 64 includes a cam shaft 69 extending in the main scanning direction X, six rotary plate cams 70 (only four of which are shown in FIG. 8) attached to the cam shaft 69, and a cam shaft. And a cam drive motor (not shown) for rotationally driving 69.

  The six rotary plate cams 70 are arranged at a predetermined interval in the main scanning direction X corresponding to the positions of the open / close plates 67a. Each rotary plate cam 70 has an arcuate cam surface. The shape (cam profile) of the cam surface of each rotary plate cam 70 is set so as to realize a selective opening / closing operation of an opening / closing plate 67a described later.

  When the cam shaft 69 is rotationally driven by the cam drive motor, the cam surface of a predetermined rotating plate cam 70 comes into contact with the cam contact surface 67b of the opening / closing plate 67a according to the rotation angle of the cam shaft 69, and opens and closes. The plate 67a is pushed up. As a result, the opening / closing plate 67a rotates upward (counterclockwise direction in FIG. 8) about the support shaft 68 and closely contacts the sealing material 71 provided along the peripheral edge of the communication hole 67. Thus, the communication hole 67 is closed by the opening / closing plate 67a. Since the suction force of the suction fan does not act on the compartment 66 with the communication hole 67 blocked, the suction force of the suction fan acts on the compartments 66 other than the compartment.

  In the present embodiment, paying attention to this, the suction force is not applied to the unnecessary suction holes 60 (the suction holes 60 located outside the conveyance path of the recording paper P) according to the width dimension of the recording paper P. By selectively closing the communication holes 67, the suction force of the suction fan is concentrated on the necessary suction holes 60 to ensure the flatness of the recording paper P.

  Specifically, as shown in FIG. 10, when printing is performed on the recording paper P on the left side of the printer among the two rows of recording paper P accommodated in the magazine M2, the right side of the printer among the six compartments 66 is displayed. In other words, the communication holes 67 of the three compartments 66 located on the side opposite to the side on which the recording paper P passes are closed by the opening / closing plate 67a. Similarly, when printing on the recording paper P on the right side of the printer, the communication holes 67 of the three compartments 66 located on the left side of the printer are closed with an opening / closing plate 67a (see FIG. 10A). Further, when printing on the wide size recording paper P accommodated in the magazine M1, the communication holes 67 of the compartments 66 located at both ends in the left-right direction of the printer among the six compartments 66 are formed by the opening / closing plates 67a. It closes (see FIG. 10B). On the other hand, when printing is simultaneously performed on two rows of recording paper P, all the opening / closing plates 67a are opened, and all the communication holes 67 of the six compartments 66 are opened.

  Such a selective opening / closing operation of the opening / closing plate 67a is realized by controlling the rotation phase of the cam drive motor by a conveyance control unit 202 described later. In the present embodiment, the opening / closing plate 67a is rotated around the support shaft 68 so that the suction force of the suction fan does not act on the unnecessary suction holes 60. For example, the lower surface (back surface) of the platen 45 A plurality of opening / closing plates 67a arranged in the main scanning direction may be provided, and each opening / closing plate 67a may be slid in the sub-scanning direction Y.

  The flushing hole 61 is for receiving a small amount of ink ejected from the ink ejection nozzle of the print head H at the start of printing in order to prevent the ink from thickening. The waste ink ejected into the flushing hole 61 is The liquid is stored in a waste liquid tank (not shown) through a waste pipe.

  The support surface 45a of the platen 45 is further formed with a recess 45c extending in the sub-scanning direction Y. An ink absorbing member 72 (see FIG. 9) is accommodated in the recess 45c. When the ink absorbing member 72 performs borderless printing for printing an image on the entire recording paper P, a part of the ink ejected from the print head H (head unit 13) is the width of the recording paper P on the support surface 45a. This is provided in order to prevent the support surface 45a of the platen 45 from being stained by the ink that has come off from the outer edge of the direction. For this reason, the concave portion 45c extends along the edge at a position corresponding to the edge in the width direction of the recording paper P on the support surface 45a on the support surface 45a and at a position corresponding to the print head H in the sub-scanning direction Y. (That is, extending in the sub-scanning direction Y).

  As shown in FIG. 11, the bottom surface of each recess 45 c is inclined downward after extending horizontally from one side of the sub-scanning direction Y to the other side. A first engagement recess 45d is formed at one end of the recess 45c in the sub-scanning direction Y, and a second engagement recess 45e is formed at the other end of the recess 45c in the sub-scanning direction Y.

  The ink absorbing member 72 is formed in a substantially rectangular parallelepiped shape extending in the sub-scanning direction Y along the recess 45c. The ink absorbing member 72 is detachably accommodated in the recess 45c via the attachment member 74. In a state where the ink absorbing member 72 is accommodated in the recess 45c, the longitudinal direction of the ink absorbing member 72 coincides with the sub-scanning direction Y.

  The mounting member 74 includes a base part 74a having a substantially trapezoidal shape when viewed from the side, to which the ink absorbing member 72 is fixed, and a first engagement that is connected to one end of the base part 74a in the longitudinal direction and protrudes to the one side. It has a protrusion 74b and a flexible piece 74c connected to the other end portion in the longitudinal direction of the base portion 74a.

  The ink absorbing member 72 is detachably fixed to the upper surface of the base portion 74a via a mounting screw (not shown).

  The lower end portion of the flexible piece 74c is connected to the lower end portion at the other end portion in the longitudinal direction of the base portion 74a. And the flexible piece 74c is comprised so that it can bend in the base longitudinal direction by using the connection part with the base 74a as a fulcrum. A claw portion 74d extending substantially horizontally toward the other side in the base longitudinal direction is formed at the upper end portion of the flexible piece 74c. In addition, a second engagement protrusion 74e is formed at an intermediate portion in the vertical direction of the flexible piece 74c so as to protrude to the other side in the base longitudinal direction.

  In a state where the ink absorbing member 72 is housed in the recess 45c, the first engagement protrusion 74b provided on the base 74a is engaged with the first engagement recess 45d, and the second engagement protrusion 74e is the second engagement protrusion 74e. It engages with the engagement recess 45e. When exchanging the ink absorbing member 72 accommodated in the recess 45c, the operator lifts the claw portion 74d upward while pressing the claw portion 74d with a fingertip and pressing the claw portion 74d to one side in the sub-scanning direction Y. Then, the flexible piece 74c bends to one side in the sub-scanning direction Y, so that the engagement between the second engagement protrusion 74e and the second engagement recess 45e is released, and the base 74a becomes the first engagement protrusion. The portion 74b is lifted upward with the fulcrum as a fulcrum (see the two-dot chain line in FIG. 11). Thus, the operator can remove the attachment member 74 from the recess 45c together with the ink absorbing member 72. After removing the mounting member 74, the operator loosens the mounting screw and replaces the ink absorbing member 72 with a new one. Then, the replacement work of the ink absorbing member 72 is completed by setting the replaced ink absorbing member 72 together with the mounting member 74 in the recess 45c.

  As described above, in the present embodiment, the ink absorbing member 72 is accommodated in the recess 45c via the mounting member 74, thereby facilitating the replacement work without complicating the shape of the ink absorbing member 72. can do.

  The cutter unit 4 is disposed on the lower side of the conveyance path of the recording paper P and the fixed blade 4a on the upper side of the conveyance path of the recording paper P, and is vertically moved with respect to the fixed blade 4a by a motor (not shown). The movable blade 4b moves to the lower side of the recording paper P, and the recording paper P is cut. Chips resulting from this cutting fall and are stored in a waste box (not shown) disposed in the lower part of the housing 3.

  The switchback unit 5 switches back the recording paper P and discharges the recording paper P from the rear end side of the recording paper P to the transport path so that the printing surface of the recording paper P faces the upper surface on the transport belt 151 of the conveyor device 150. Is.

  As shown in FIG. 2, FIG. 12 and FIG. 13, the switchback portion 5 includes a pressure-bonding type switchback roller pair 173 including a lower driving roller 173a and an upper driven roller 173b, and the switchback roller. A pair of first guide members 174 that are provided on the upstream side of the pair 173 so as to sandwich the transport path and guide the recording paper P transported from the transport roller pair 26 after cutting to the switchback roller pair 173, and the switched back recording A switch-backed recording paper P provided so as to sandwich a conveyance path between a pressure-feed type supply roller pair 175 for supplying the paper P to a back surface printing unit 6 to be described later, and a switchback roller pair 173 and a supply roller pair 175. And a pair of second guide members 176 for guiding the toner to the supply roller pair 175.

  The drive roller 173a of the switchback roller pair 173 is forwardly rotated by a motor (not shown) to sandwich the recording paper P and transport it to the front side of the printer, and reversely rotated to sandwich the recording paper P and transport it to the rear side of the printer. And is configured to be possible.

  The switchback roller pair 173 and the first guide member 174 can be moved integrally around the rotation axis of the drive roller 173a of the switchback roller pair 173 by a motor (not shown). The relative position of the driven roller 173b with respect to the driving roller 173a of the roller pair 173 is positioned almost directly above the driving roller 173a as shown in FIG. 12, and the first position for conveying the recording paper P to the rear side of the printer. As shown in FIG. 13, it is positioned at the rear side of the printer with respect to the driving roller 173 a, and is switched to the second position where the switched back recording paper P is supplied from the rear end side to the back surface printing unit 6. It has become.

  Here, a switchback operation for switching back the recording paper P conveyed from the conveyance roller pair 26 after cutting will be described. When the switchback roller pair 173 receives the recording paper P conveyed from the conveying roller pair 26 after cutting, the driving roller 173a is rotating forward and the driven roller 173b is in the first position. When the recording paper P is conveyed to the rear side of the printer by the switchback roller pair 173 by an amount such that the rear end of the recording paper P is positioned on the first guide member 174 (see FIG. 12), the drive roller 173a rotates forward. To stop.

  At this time, the leading end portion of the recording paper P is bent and bent downward due to the weight of the recording paper P. When the recording paper P is stiff and does not bend due to its own weight, the leading end of the recording paper P comes into contact with the curved guide plate 177 provided on the downstream side in the transport direction, so that the lower side along the curved guide plate 177 It can be bent to.

  Subsequently, the switchback roller pair 173 and the first guide member 174 are rotated clockwise in FIG. 12 to switch the driven roller 173b from the first position to the second position. Thereby, the rear end side (front side of the printer) of the recording paper P is lifted.

  Thereafter, the drive roller 173a is rotated in the reverse direction, and the recording paper P is conveyed from the rear end side toward the supply roller pair 175 disposed on the upper side of the printer. The recording paper P to be switched back by the switchback roller pair 173 passes through the first guide member 174 and the second guide member 176 and reaches the supply roller pair 175.

  In this embodiment, the position of the switchback roller pair 173 is switched between the first position and the second position by moving the driven roller 173b around the drive roller 173a of the switchback roller pair 173. However, the present invention is not limited to this configuration. For example, the configuration is such that both the driving roller 173a and the driven roller 173b are movable, and the position of the entire switchback roller pair 173 is changed to change the first position and the first position. The position 2 may be switched.

  In this embodiment, the switchback roller pair 173 includes the driving roller 173a that conveys the recording paper P and the driven roller 173b that rotates following the driving roller 173a. However, the driven roller 173b can be driven. Thus, both of the rollers constituting the switchback roller pair 173 may be configured by the drive roller 173a.

  A recording paper collection box 83 that opens upward is provided below the switchback unit 5. The recording paper collection box 83 is for collecting the recording paper P remaining in the transport path when an error (for example, a paper jam error) occurs. When an error occurs, the recording paper P remaining on the transport path is transported to the switchback unit 5 by the recording paper transport mechanism. The switchback unit 5 receives the recording paper P and discharges it to the collection box 83. As a result, when an error occurs, the recording paper P remaining in the transport path can be easily removed without opening a necessary portion of the printer cover (housing 3).

  The back surface printing unit 6 is composed of a dot impact type thermal printer, and is disposed on the back surface side of the recording paper P (on the rear side of the printer with respect to the transport path).

  On the downstream side of the conveyance of the back surface printing unit 6, a conveyance roller pair 28 for feeding the recording paper P after the back surface printing is disposed. Then, the recording paper P is transported to the drying unit 7 on the downstream side by the rotation of the transport roller pair 28.

  The drying unit 7 records a suction fan 154 for taking air into the drying device 153, a heater 155 for heating the air taken in by the suction fan 154, and the air heated by the heater 155 as dry air. The exhaust nozzle unit 156 sprays on the printing surface of the paper P.

  The decurling unit 8 includes a driving conveyance roller 81 and a decurling roller 82 configured to be movable around the driving conveyance roller 81. The decurling unit 8 switches the position of the decurling roller 82 between the transport position and the decurling position according to the type of the recording paper P (roll paper / sheet paper).

  The conveyance position is defined as a position where the decurling roller 82 is located directly above the driving conveyance roller 81. At this transport position, the recording paper P is transported without being decurled by both rollers 81 and 82.

  The decurling position is defined as a position where the decurling roller 82 is rotated in the clockwise direction around the driving conveying roller 81 from the conveying position. At this decurling position, the recording paper P is conveyed while being decurled by both rollers 81 and 82.

  The decurling unit 8 controls the decurling roller 82 to the transporting position when the recording paper P transported from the drying unit 7 is the sheet-shaped recording paper P fed from the manual feeding unit. When the recording paper P is a roll-shaped recording paper P drawn from the magazines M1 and M2, the decurling roller 82 is controlled to the decurling position. Accordingly, the recording paper P drawn from the magazines M1 and M2 can be surely decurled without unnecessarily curling the recording paper P supplied from the manual supply unit.

  The accumulating device 210 is for accumulating the recording paper P conveyed from the conveyor device 150, and is disposed at the upper and lower ends of the accumulating main body 211, and a box-shaped accumulating main body 211 having an opening on the front side of the printer. An endless stacking belt 213 wound around the pair of rollers (not shown) with an appropriate tension, and a stacking plate 212 provided on the outer peripheral surface of the stacking belt 213 at substantially equal intervals. Yes. The roller pair is connected to a drive motor (not shown) for rotating the accumulation belt 213 to move the accumulation plate 212 in the transport direction.

  Of the plurality of stacking plates 212, the stacking plate 212 exposed to the outside of the stacking main body 211 moves downward following the rotation of the stacking belt 213, and is accommodated inside the stacking main body 211. The collecting plate 212 is configured to move upward following the rotation of the collecting belt 213. That is, the accumulation plate 212 is configured to be able to rotate continuously around the roller pair together with the accumulation belt 213.

  The stacking plate 212 waits at the delivery position of the recording paper P on the downstream side of the conveyance belt 151 so that the plate surface is horizontal and substantially flush with the belt surface of the conveyance belt 151. After the number of sheets corresponding to 1 is accumulated, the recording paper P of the next order is conveyed downward by the accumulation belt 213 before being conveyed.

-Control system configuration-
As shown in FIG. 14, the inkjet printer has a microprocessor 201 (hereinafter referred to as a CPU), a conveyance control unit 202 connected to the CPU 201 via a data bus, a head control unit 203, and a print control. Unit 204, semiconductor memory RAM / ROM 205, and communication interface 206.

The conveyance control unit 202 controls the operation of the recording paper conveyance mechanism. The head control unit 203 controls the print head H by driving a drive belt 12 for reciprocating the print head H in the main scanning direction and supplying a voltage having a predetermined waveform to each piezoelectric element. . The communication interface 206 is for transmitting and receiving information to and from the reception block 200. The print control unit 204 performs control for realizing printing of image data on the recording paper P based on the image data received from the receiving block 200 via the communication interface 206. Here, the order information includes print channel information for specifying the size of the recording paper P to be printed, and print form information for specifying the number of printed sheets.
-Printhead control-
As described above, the print head H ejects ink at a predetermined timing during each scan while being forward-scanned and backward-scanned in the main scanning direction X with respect to the recording paper P conveyed intermittently. Thus, an image composed of a large number of ink dots is printed on the recording paper P.

  Here, in the printer A having the switchback unit 5 as in this embodiment, when the switchback processing time in the switchback unit 5 becomes long, the conveyance of the recording paper P is stopped on the upstream side of the switchback unit 5. I have to do it.

  As a result, a printing waiting time Tw for interrupting the printing process on the recording paper P by the print head H occurs, and banding occurs at the boundary between the print images before and after the interruption.

  Therefore, in this printer A, whether or not the print waiting time Tw occurs when the print processing on the recording paper P is executed by scanning the print head H at a preset reference scanning time interval Tk. Is predicted before the printing process on the recording paper P is started, and the scanning time interval of the print head H is set based on the prediction, thereby preventing the occurrence of the printing waiting time Tw.

  Prediction of whether or not the print waiting time Tw occurs is performed by the print control unit 204 based on the size information of the recording paper P included in the print channel information in advance.

  When the print control unit 204 predicts that the printing waiting time Tw does not occur, the print control unit 204 sets the scanning time interval of the print head H to the reference scanning time interval Tk, while predicting that the printing waiting time Tw occurs. First, the scanning time interval of the print head H is set to a predetermined time interval Ts longer than the reference scanning time interval Tk so that the printing waiting time Tw does not actually occur.

  The print control unit 204 instructs the head control unit 203 to drive the print head H at the set scanning time interval, and also sends the recording paper P to the transport control unit 202. A command is issued so that intermittent conveyance is performed in synchronization with the scanning of H.

  The print control unit 204 maintains the scan time interval of the print head H at a value set before the start of printing from the start to the end of printing of one image.

  Next, the setting process of the scanning time interval of the print head H in the print control unit 204 will be specifically described based on the flowchart of FIG. Note that the following prediction processing in step S4 and estimation processing in steps S7 and S8 are performed under the assumption that the scanning time interval of the print head H is equal to the reference scanning time interval Tk.

  In step S1, it is determined whether or not there is a request to start printing on the recording paper P. If this determination is NO, the process returns. If YES, the process proceeds to step S2.

  In step S2, the size information of the printed recording paper P and the printing time information of the printed recording paper P are read based on the print channel information.

  In step S3, the size information of the recording paper P to be printed and the image information of the image to be printed are read.

  In step S4, it is predicted whether or not the preceding recording paper P switchback process is executed during the printing process on the recording paper P. Then, if this prediction is NO, the process proceeds to step S11, whereas if this prediction is YES, the process proceeds to step S5.

  In step S5, based on the print channel information, it is determined whether or not the length of the recording paper P predicted to be executed in step S4 (the length in the transport direction) is equal to or greater than a predetermined length. If this determination is NO, the process proceeds to step S11, whereas if this determination is YES, the process proceeds to step S6.

  In step S6, it is predicted that a printing waiting time Tw resulting from the switchback process of the preceding recording paper P will occur, and a program for estimating the length of the printing waiting time Tw is called.

  In step S7, the length of the print waiting time Tw is estimated by executing the called program. Specifically, based on the length in the transport direction of the recording paper P predicted to be subjected to the switchback process in the switchback unit 5 and the transport path length from the printing unit 2 to the switchback unit 5, The printing waiting time Tw is estimated.

  In step S8, it is necessary from the start to the end of the printing based on the size information of the recording paper P to be printed and the image information of the image to be printed on the recording paper P read in step S3. The total number N of scans of the print head H is estimated.

  In step S9, the scan time interval of the print head H is set to a predetermined time interval Ts longer than the reference scan time interval Tk. Specifically, the predetermined time interval Ts is calculated as Ts = Tw / (N−1) based on the printing waiting time Tw predicted in step S6 and the total number of scans N estimated in step S8. Then, a necessary control signal is output to the head controller 203 in order to cause the print head H to scan at the set scanning time interval.

  In step S10, a necessary control signal is output to the conveyance control unit 202 so that the recording paper P is intermittently conveyed in synchronization with the scan of the print head H, and then the process returns.

  In step S11 that proceeds when the determination in step S4 or S5 is NO, it is predicted that the print waiting time Tw does not occur.

  In step S12, the scanning time interval of the print head H is set to the reference scanning time interval Tk. Then, in order to cause the print head H to scan at the set scanning time interval, a necessary control signal is output to the head control unit 203, and then the process proceeds to step S10.

  Thus, in the embodiment, the print control unit 204 executes the printing process on the recording paper P based on the assumption (assuming that the scanning time interval of the print head H is equal to the reference scanning time interval Tk). In this case, during the printing process, the switchback unit 5 determines whether or not the switchback process is executed for the recording paper P longer than a predetermined length (hereinafter referred to as a long recording paper P). If it is determined that the printing is to be executed, it is predicted that the printing waiting time Tw will occur. When the print control unit 204 predicts that the print wait time Tw will occur (when the determination in step S5 is YES), the print head H is scanned so that the print wait time Tw does not actually occur. The time interval is set to a predetermined time interval Ts longer than the reference scanning time interval Tk.

  Therefore, even if the switchback process for the long recording paper P is executed by the switchback unit 5 during the printing process on the recording paper P by the print head H, the printing process is not interrupted. The printing process can be executed while keeping the scanning time interval of the head H constant. Therefore, banding and color unevenness can be prevented from occurring in the printed image, and the image quality of the printed image can be improved.

  In the embodiment, the print control unit 204 sets the predetermined time interval Ts to Ts = Tw / (N−1) + Tk (Tw: length of the print waiting time, N: total number of scans of the print head. ) To satisfy the relationship.

  For this reason, the printing waiting time Tw predicted in step S6 can be equally allocated to the waiting time (= scanning time interval) between each scan of the print head H. Therefore, it is possible to prevent the printing waiting time Tw from occurring without increasing the scanning time interval of the print head H during the printing process more than necessary. Therefore, it is possible to improve the image quality of the printed image as much as possible while shortening the printing processing time.

  In the above-described embodiment, when the print control unit 204 predicts that the print waiting time Tw does not occur (when the determination in step S4 or S5 is NO), the scan time interval of the print head H is set as the reference scan. Set to time interval Tk. Therefore, the print processing time can be shortened by setting the reference scanning time interval Tk to, for example, the lower limit value of the range in which the image quality of the printed image can be maintained.

(Other embodiments)
The configuration of the present invention is not limited to the above embodiment, but includes various other configurations. That is, in the embodiment, the print control unit 204 sets the predetermined time interval Ts to Ts = Tw / (N−1) + Tk (Tw: length of the print waiting time, N: total number of scans of the print head. However, the present invention is not limited to this, and the predetermined time interval Ts may be a time interval satisfying the relationship Ts> Tw / (N−1) + Tk.

  In the embodiment, the print control unit 204 determines whether or not the print waiting time Tw occurs based on the size of the recording paper P processed by the switchback unit 5. However, the present invention is not limited to this. For example, this determination may be performed in consideration of the length of the transport path from the switchback unit 5 to the drying unit 7, the transport speed of the recording paper P in the drying unit 7, and the like. Good. In this case, the switchback unit 5 and the drying unit 7 constitute an aftertreatment device.

  In the embodiment, the print control unit 204 predicts whether or not the print waiting time Tw occurs before the print head H starts the printing process on the recording paper P, and the print waiting time Tw In the case where it is predicted to occur, the scanning time interval of the print head H is set to a predetermined time interval Ts so as to be kept constant during the printing process. However, the present invention is not limited to this. By executing the printing waiting time Tw prediction process in parallel with the printing process on the recording paper P by H, the scanning time interval of the print head H is changed according to the predicted change in the printing waiting time Tw. It may be.

  Specifically, for example, the print control unit 204 stores in advance three scan patterns in which the scan time intervals of the print head H are T1, T2, and T3 (Tk <T1 <T2 <T3: Tk reference scan time interval). In addition, the scanning time interval of the print head H may be changed stepwise from T1 to T2 to T3 as the predicted printing waiting time Tw becomes longer. However, if the change width ΔT (T1-Tk, T2-T1, T3-T2) is large, the color of the print image before and after changing the scanning time interval is greatly changed, and the image quality of the print image is deteriorated. Become. Therefore, it is preferable to set the change width ΔT of the scanning time interval by conducting a print test or the like in advance so that even if a change in the hue of the print image occurs, it cannot be identified with the naked eye.

  In this way, even if the execution status of the post-processing of the preceding recording paper P changes due to a conveyance failure or the like (that is, even if the length of the print waiting time Tw predicted by the print control unit 204 changes), In response to this change, the scanning time interval of the print head H can be changed to reliably suppress the occurrence of the printing waiting time Tw.

  The present invention discharges ink onto a recording sheet that is intermittently conveyed along the conveyance path, while ejecting ink while scanning in the main scanning direction orthogonal to the recording sheet conveyance direction. This is useful for a printer having a print head for printing the image, and particularly useful for a printer in which a switchback device is arranged on the downstream side of the conveyance of the print head.

A Printer P Recording paper X Main scanning direction Y Sub-scanning direction H Print head Tk Reference scanning time interval Ts Predetermined time interval Tw Length of printing waiting time N Total number of print head scans 5 Switchback unit (post-processing device)
204 Print control unit (prediction means, setting means, print control means)

Claims (4)

A print that prints an image on a recording sheet that is intermittently conveyed along the conveyance path by ejecting ink while scanning in the main scanning direction orthogonal to the recording sheet conveyance direction when the conveyance is stopped. A printer comprising: a head; and a post-processing device that is disposed downstream of the print head and that is disposed downstream of the print head and that performs post-processing on a recording sheet that has been printed by the print head.
When printing processing on the recording paper is executed by scanning the print head at a preset reference scanning time interval, post-processing is performed on the recording paper that has been printed in the post-processing device during the printing processing. Predicting means for predicting whether or not a print waiting time will occur by executing
Setting means for setting a scan time interval of the print head based on a prediction result by the prediction means;
Printing control means for executing a printing process on the recording paper by scanning the print head at a scanning time interval set by the setting means,
The setting means sets the scanning time interval of the print head to the reference scanning time interval when the prediction means predicts that the printing waiting time does not occur, while predicting that the printing waiting time occurs. In this case, the scanning time interval of the print head is set to a predetermined time interval longer than the reference scanning time interval so that the printing waiting time does not actually occur. Printer. The printer according to claim 1.
The predicting unit is configured to perform a prediction as to whether or not the printing waiting time occurs before performing a printing process on the recording paper by the print head,
A printing waiting time estimating means for estimating the length of the printing waiting time when the predicting means is predicted to generate the printing waiting time;
A scanning number estimation unit for estimating the total number of scannings of the print head required from the start to the end of the printing process on the recording paper by the print head when the prediction unit predicts that the printing waiting time will occur. Further comprising
The setting means is configured to set the scanning time interval of the print head to the predetermined time interval satisfying the relationship of the following expression when the prediction waiting time is predicted to occur by the prediction means. A printer characterized by being.
Ts = Tk + Tw / (N-1)
Tk: the reference scanning time interval Ts: the predetermined time interval Tw: the length of the printing waiting time N: the total number of scanning times of the print head The printer according to claim 1 or 2,
The post-processing device is disposed in a transport path downstream of the print head and receives the recording paper from the leading end side and changes the transport direction, and then discharges the recording paper from the trailing end side. A printer that is configured to perform the above. The printer according to claim 3.
When the printing unit performs a printing process on the recording paper by scanning the print head at a preset reference scanning time interval, the predicting unit has a predetermined length or more in the post-processing device during the printing process. It is configured to predict whether or not the switchback process is performed on the recording paper, and to predict that the print waiting time will occur when it is predicted to be performed. Printer.

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