JP2017190213A - Printer and control method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow tension of a printing medium in feeding operation at the time of printing processing to be stabilized.SOLUTION: A printer comprises: a roll drive unit 38 rotating and driving a roll body R in a direction in which a printing medium A is fed from the roll body R; a feeding drive unit 36 driving a feed roller 31; and a controller 13 controlling the feeding drive unit 38 and the roll drive unit 36, and performing feeding operation feeding the printing medium A a plurality of times while applying tension to the printing medium A. The controller 13 corrects target tension at the time of the n(n≥2)-th feeding operation based on detection tension of the feeding operation of time preceding (n-1)-th time out of the plurality of times of the feeding operation, controls the n-th feeding operation based on the target tension corrected, and executes a pseudo feeding step of performing the feeding operation one time or more before printing processing.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a printing apparatus that performs printing on a printing medium and a method for controlling the printing apparatus.

  Conventionally, as a printing apparatus, a pair of rotating holders that hold a roll body around which a print medium (medium) is wound, a driving roller that pulls out and sends the print medium from the roll body, and a direction in which the print medium is sent from the roll body, It is known to have a roll motor that rotates a roll body via a rotary holder and a feed motor that drives a drive roller, and controls the roll motor and the feed motor to perform a feed operation for feeding a print medium. (See Patent Document 1). In this printing apparatus, during the printing process, the feed operation (line feed operation) is intermittently performed a plurality of times. At this time, the target tension of the n-th feed operation is set to the (n-1) th feed before the feed operation. Correction is performed based on the detected tension during operation, and the n-th feeding operation is controlled based on the corrected target tension. That is, it is configured to detect the tension during the feeding operation that has already been performed and feed back this to control the next feeding operation (tension feedback control).

Japanese Patent Laying-Open No. 2015-231910

  However, in such a configuration, as shown in FIG. 5, if the feeding operation is performed after a certain number of times of feeding operation, the tension of the print medium is stabilized due to the influence of the tension feedback control. During the feeding operation, the tension of the print medium was not stable. In particular, when the weight of the printing medium is heavy, this effect appears remarkably. As a result, the printing medium feeding distance per feeding operation is not stable, and the printing result is not stable. For example, there is a difference in the printing result between the beginning of the printing process and the other printing processes, and a stable printing process cannot be performed.

  In view of such problems, an object of the present invention is to provide a printing apparatus and a printing apparatus control method capable of stabilizing the tension of a printing medium in a feeding operation during printing processing.

  The printing apparatus of the present invention includes a holding unit that holds a roll body around which a print medium is wound, a feeding unit that draws and sends the printing medium from the roll body, a printing unit that performs printing on the printing medium that is sent by the feeding unit, A roll drive unit that rotationally drives the roll body via a holding unit in a direction in which the print medium is fed from the roll body, a feed drive unit that drives the feed unit, a feed drive unit, and a roll drive unit are controlled, and the print medium A feed control unit that feeds the print medium while adding tension to the feed control unit a plurality of times, and the feed control unit sets the target tension during the n (n ≧ 2) -th feed operation to the feed operation a plurality of times. Is corrected based on the detected tension at the time of the feeding operation before the (n-1) th time, and the n-th feeding operation is controlled based on the corrected target tension, and the printing operation and the feeding operation by the printing unit And alternately Prior to printing process, and executes a pseudo feed step of feeding operation one or more times.

  The control method of the printing apparatus of the present invention includes a holding unit that holds a roll body around which a print medium is wound, a feeding unit that pulls out the printing medium from the roll body, and a printing that performs printing on the printing medium that is sent by the feeding unit. A roll drive unit that rotates the roll body via a holding unit and a feed drive unit that drives the feed unit in a direction in which the print medium is fed from the roll body, and a feed drive unit and a roll drive unit Is a control method for a printing apparatus that performs a feeding operation for sending a print medium while applying tension to the printing medium a plurality of times, and a target tension at the n (n ≧ 2) th feeding operation is set to a plurality of times. Correction is made based on the detected tension at the time of the (n-1) -th feed operation before the feed operation, and the n-th feed operation is controlled based on the corrected target tension. Feeding action and Before one another with the print processing, and executes a pseudo feed step of feeding operation one or more times.

  According to these configurations, since the first one or more feeding operations are performed before the printing process, the tension of the printing medium during the feeding operation is controlled by the tension feedback control as shown in FIG. The printing process can be performed after the state becomes stable. That is, since the feeding operation for feedback is performed at least once before the printing process, and this is fed back to perform the feeding operation at the time of the printing process, the tension of the printing medium in the feeding operation at the time of the printing process is increased. The printing process can be performed stably.

  In the above printing apparatus, it is preferable to perform the feeding operation in the pseudo feeding step at the feeding speed of the feeding operation in the printing process.

  Further, it is preferable to perform the feeding operation in the pseudo feeding step at the feeding distance of the feeding operation in the printing process.

  According to these configurations, since the feed operation in the pseudo feed step is executed at the feed speed and the feed distance adjusted at the time of the feed operation in the printing process, the pseudo feed step is as close as possible to the feed operation in the printing process. The feeding operation can be performed with As a result, it is possible to obtain the same detected tension as the feeding operation in the printing process, and to improve the accuracy of the tension feedback control.

  On the other hand, it is preferable that the feed control unit executes a cueing step of moving the page tip of the print medium to the printing unit before the printing process, and the pseudo feed step is executed during the cueing step.

  According to this configuration, since the pseudo feed step is executed during the cueing step, the pseudo feed step can be executed immediately before the printing process. Therefore, the feeding operation at the pseudo feeding step can be performed in a state close to the feeding operation in the printing process. Therefore, the accuracy of tension feedback control can be further improved.

  The pseudo-feeding step is preferably executed within a predetermined time before starting the printing process.

  According to this configuration, the feeding operation in the pseudo feeding step can be performed in a state close to the feeding operation in the printing process. Therefore, the accuracy of tension feedback control can be improved.

  Furthermore, it is preferable that one or more feeding operations in the pseudo-feeding step are performed without a time interval corresponding to the printing operation between the feeding operations.

  According to this configuration, the tact time can be improved because the feed operation is performed one or more times in the pseudo-feed step without leaving a time interval corresponding to the printing operation.

  The pseudo-feeding step is preferably executed for each print job.

  According to this configuration, each print process based on each print job can be stably performed.

1 is a plan view showing a schematic configuration of a large format printer according to an embodiment of the present invention. It is the side view which showed schematic structure of the large format printer. It is the block diagram which showed the function structure of the controller. It is the block diagram which showed the structure of the roll motor control part. It is the graph which showed the tension concerning a printing medium at the time of the conventional multiple times of feeding operation. 6 is a graph showing a plurality of feeding operations. 5 is a flowchart illustrating a preparation operation for print processing. It is the graph which showed the tension concerning a printing medium at the time of a plurality of feeding operations of the present invention.

  Hereinafter, a printing apparatus and a printing apparatus control method according to an embodiment of the present invention will be described with reference to the accompanying drawings. In the embodiment, a large format printer to which the printing apparatus and the control method of the printing apparatus of the present invention are applied is exemplified. This large format printer (printing apparatus) prints a large format print medium (medium) from a roll body while feeding the large format print medium by an inkjet method. In particular, this large format printer has a configuration in which the feeding operation in the printing process is stabilized by performing the feeding operation for feedback several times before the printing process in the configuration in which the feeding operation is performed a plurality of times by feedback control. It is what you have. In addition, the roll body set in this large format printer is obtained by winding a long print medium around a cylindrical core in a roll shape. The print medium is recording paper, film, cloth, or the like.

  As shown in FIGS. 1 and 2, the large format printer 1 includes a medium feeding mechanism 11 that sends the printing medium A in the paper feeding direction, and a printing mechanism 12 that performs printing on the printing medium A that is sent by the medium feeding mechanism 11. (Printing unit) and a controller 13 (feed control unit) for controlling them. The large-format printer 1 performs printing on the printing medium A by a serial printing method by alternately repeating the feeding operation by the medium feeding mechanism 11 and the printing operation by the printing mechanism 12.

  The printing mechanism 12 performs printing on a print medium A that is fed by a feed roller 31 that will be described later. The print head 21, a carriage 22 that mounts the print head 21, and the print head 21 reciprocate via the carriage 22. A reciprocating mechanism 23 that moves, and a platen 24 that faces the print head 21 are provided.

  The print head 21 has a nozzle row (not shown) extending in the paper feed direction of the print medium A by the medium feed mechanism 11 and ejects ink from a plurality of ejection nozzles of the nozzle row by an inkjet method. On the other hand, the reciprocating mechanism 23 reciprocates the print head 21 in a direction intersecting the paper feeding direction. The printing mechanism 12 performs a printing operation on the printing medium A by driving the printing head 21 by the reciprocating mechanism 23 while moving the printing head 21 forward or backward.

  On the other hand, a plurality of suction holes 26 penetrating vertically are formed in the platen 24. A suction fan 27 is provided below the platen 24. Then, when the suction fan 27 is operated, the inside of the suction hole 26 is set to a negative pressure, and the print medium A on the platen 24 is sucked and held. In the present embodiment, a printing operation is performed on the print medium A while the print medium A is sucked and held on the platen 24.

  The medium feeding mechanism 11 includes a roll holding unit 32 (holding unit) that holds the roll body R around which the printing medium A is wound, a feeding roller 31 (feeding unit) that feeds the printing medium A while being drawn from the roll body R, and Is provided. Further, the medium feeding mechanism 11 includes a roll driving unit 38 that rotationally drives the roll body R, and a feeding roller driving unit 36 (feeding driving unit) that drives the feeding roller 31.

  The feed roller 31 is composed of a nip roller composed of a drive roller 31a and a driven roller 31b. That is, the drive roller 31a and the driven roller 31b of the feed roller 31 rotate and feed the print medium A while being sandwiched between them.

  The feed roller drive unit 36 includes a feed motor 41 serving as a power source, a feed gear train 42 that transmits the power of the feed motor 41 to the feed roller 31, and a feed rotation detection unit that detects the rotational position and direction of the feed roller 31. 43. The feed motor 41 is, for example, a DC motor. The feed gear train 42 is connected to a feed input gear 31c provided on the drive roller 31a. Then, the power from the feed motor 41 is transmitted to the feed input gear 31c via the feed gear train 42, whereby the drive roller 31a rotates and the driven roller 31b rotates accordingly. Thus, the feed roller 31 is rotationally driven by the power of the feed motor 41.

  The feed rotation detector 43 detects the rotation position and rotation direction of the drive roller 31a. Specifically, the feed rotation detection unit 43 is configured by a rotary encoder provided with a disk-like scale provided on the output shaft of the feed motor 41 and a photo interrupter. That is, the feed rotation detection unit 43 detects the rotation position and the rotation direction of the drive roller 31a by detecting the rotation position and the rotation direction of the output shaft of the feed motor 41.

  The roll holding part 32 includes a pair of rotation holders 32a that hold the roll body R, and holder support parts (not shown) that rotatably support the pair of rotation holders 32a. The pair of rotation holders 32a are respectively inserted into both ends of the core of the roll body R, and hold the roll body R from both sides. One of the pair of rotation holders 32 a has a roll input gear 32 b that receives power from the roll drive unit 38.

  The roll drive unit 38 includes a roll motor 51 serving as a power source, a roll gear train 52 that transmits the power of the roll motor 51 to the rotation holder 32a, and a roll rotation detection unit 53 that detects a rotation position and a rotation direction of the roll body R. . The roll motor 51 is, for example, a DC motor. The roll gear train 52 is connected to the roll input gear 32b of the rotation holder 32a that holds the roll body R. Then, the power from the roll motor 51 is transmitted to the roll input gear 32b via the roll gear train 52, whereby the rotation holder 32a provided with the roll input gear 32b rotates, and the roll held by this The body R rotates. In this way, the roll body R is rotationally driven by the power of the roll motor 51 via the rotation holder 32a.

  The roll motor 51 is configured to be capable of forward / reverse drive, and is configured to be capable of rotationally driving the roll body R in the feeding direction and the rewinding direction. In the present embodiment, the roll body R is rotationally driven in the feeding direction by driving the roll motor 51 in the forward direction, and the roll body R is rotationally driven in the rewinding direction by driving the roll motor 51 in the reverse direction. The feeding direction is a rotation direction in which the printing medium A is sent (rolled) from the roll body R. On the other hand, the rewinding direction is a rotating direction in which the printing medium A is rewound onto the roll body R. In the feeding operation of the printing medium A, the roll body R is rotationally driven in the feeding direction, and the paper feeding by the feeding roller 31 is assisted.

  The roll rotation detection unit 53 detects the rotation position and rotation direction of the roll body R. Specifically, the roll rotation detection unit 53 is configured by a rotary encoder including a disc scale provided on the output shaft of the roll motor 51 and a photo interrupter. That is, the roll rotation detection unit 53 detects the rotation position and rotation direction of the roll body R by detecting the rotation position and rotation direction of the output shaft of the roll motor 51.

  The controller 13 controls each part of the large format printer 1. Specifically, the controller 13 includes a CPU (Central Processing Unit) 71, a ROM (Read Only Memory) 72, a RAM (Random Access Memory) 73, a PROM (Programmable ROM) 74, and an ASIC (Application Specific Integrated Circuit). ) 75, a motor driver 76, and a bus 77. Each pulse signal from the feed rotation detection unit 43 and the roll rotation detection unit 53 is input to the controller 13.

  In the large-format printer 1 configured as described above, when a print job execution command is received, the printing medium A is printed by the printing mechanism 12 by the printing operation (main scanning) and the medium feeding mechanism 11 by the printing width of the printing mechanism 12. The line feed operation (sub-scanning), which is a feed operation for sending the image, is alternately repeated to perform the printing process.

  Next, the functional configuration of the controller 13 will be described with reference to FIG. As shown in FIG. 3, the controller 13 includes a main control unit 81, a feed motor control unit 82, and a roll motor control unit 84. Each of these functional units is realized by cooperation of hardware configuring the controller 13 and software stored in a memory such as the ROM 72.

  The main control unit 81 gives a command to the feed motor control unit 82 and the roll motor control unit 84. The main control unit 81 drives the feed motor 41 and the roll motor 51 independently, or the feed motor control unit 82 and the roll motor control unit 84 so as to drive the feed motor 41 and the roll motor 51 synchronously. Can be given a command. In this embodiment, a command is given to the feed motor control unit 82 and the roll motor control unit 84 so that the feed motor 41 and the roll motor 51 are synchronously driven in the feed operation of feeding the print medium A. Thus, the feed roller 31 and the roll body R are rotationally driven, and the print medium A is fed while applying tension to the print medium A between the roll body R and the feed roller 31.

  The feed motor control unit 82 drives and controls the feed motor 41 through PWM (Pulse Width Modulation) control via the motor driver 76. The feed motor control unit 82 outputs the PID-controlled duty value to the motor driver 76 based on the rotation speed and rotation position of the drive roller 31 a detected by the feed rotation detection unit 43. That is, the feed motor control unit 82 controls the feed motor 41 by PID control, thereby driving the feed roller 31 at a specified rotational speed and rotational distance and feeding the printing medium A.

  The roll motor control unit 84 drives and controls the roll motor 51 by PWM control via the motor driver 76. When performing the feeding operation, the roll motor control unit 84 drives the roll motor 51 to rotate in the forward direction and rotationally drives the roll body R, thereby assisting paper feeding by the feeding roller 31 and applying tension applied to the printing medium A. Adjust to the prescribed tension. Specifically, as shown in FIG. 4, the roll motor control unit 84 includes a motor output value calculation unit 91 and a target tension correction unit 92 as a configuration related to the feeding operation.

ここで、ｒはロール体Ｒの半径、Ｍはロールギア列５２による減速比、Duty(max)はデューティ値の最大値、Ｔｓはロールモーター５１の起動トルク、ａおよびｂは予め算出される係数である。係数ａ、ｂは、低速の回転速度Ｖｌでロール体Ｒを回転駆動したときのデューティ値Duty(ro)_lと、高速の回転速度Ｖｈでロール体Ｒを回転駆動したときのデューティ値Duty(ro)_hと、を取得し、これらの値を（２）式に代入して得られた、係数ａおよびｂに関する連立方程式を解くことによって算出する。
Duty(ro)=ａ×Ｖ＋ｂ （２） The motor output value calculation unit 91 calculates the relationship between the feed roller 31 and the roll body R from Duty (ro), which is a duty value required to rotate the roll body R at the rotational speed V, as shown in the equation (1). The motor output value Dx is obtained by subtracting Duty (f), which is a duty value (hereinafter referred to as “tension control value”) necessary to apply a predetermined tension F to the print medium A in the meantime.

Here, r is the radius of the roll body R, M is the reduction ratio by the roll gear train 52, Duty (max) is the maximum duty value, Ts is the starting torque of the roll motor 51, and a and b are coefficients calculated in advance. is there. The coefficients a and b are the duty value Duty (ro) _l when the roll body R is rotationally driven at a low rotational speed Vl, and the duty value Duty (ro) when the roll body R is rotationally driven at a high rotational speed Vh. ) _h, and by calculating these equations and substituting these values into equation (2), the simultaneous equations relating to the coefficients a and b are calculated.
Duty (ro) = a × V + b (2)

  Therefore, the motor output value Dx can be calculated by substituting the target tension, which is the target value of the tension F, into F in the equation (1). As described above, the motor output value calculation unit 91 calculates the motor output value Dx based on the target tension. Then, the calculated motor output value Dx is output to the motor driver 76.

  When the target tension correcting unit 92 performs the feeding operation a plurality of times, the target tension at the n (n ≧ 2) th feeding operation commanded from the main control unit 81 is set to (n -1) Correction is made based on the detected tension during the feeding operation before the first time. Specifically, the target tension correction unit 92 includes a feed current calculation unit 101, a reference current calculation unit 102, a current subtraction unit 103, a current tension conversion unit 104, a tension subtraction unit 105, and a tension correction amount calculation. Unit 106 and a tension adding unit 107.

  The feed current calculation unit 101 calculates a feed current Ia (k) that is a current that has flowed through the feed motor 41 during a feed operation at a predetermined calculation cycle, for example, a 1 msec cycle. Here, Ia (k) means the feed current Ia calculated k-th in a predetermined calculation cycle. The calculated feed current Ia (k) is input to the current subtraction unit 103.

  Further, the reference current calculation unit 102 calculates the reference current Ib (k), which is the current that has flowed through the feed motor 41, during the reference current measurement operation, in the same calculation cycle as the feed-time current calculation unit 101, in this case, 1 msec cycle. . In this reference current measurement operation, the controller 13 drives the feed motor 41 at the same rotational speed and the same drive time as in the feed operation while the print medium A is slackened. The controller 13 preferably performs the reference current measurement operation for each print job a plurality of times, and the reference current calculation unit 102 preferably sets the average value as the reference current Ib (k). The calculated reference current Ib (k) is input to the current subtracting unit 103.

Here, the current I flowing through the feed motor 41 can be calculated by the equation (3).
I = (E × Duty−Ke × ω) / RR (3)
E is the power supply voltage, Duty is the PWM control value output to the feed motor 41, Ke is the counter electromotive force constant of the feed motor 41, ω is the rotational speed of the feed motor 41, and RR is the resistance of the feed motor 41. The back electromotive force constant Ke and the resistance RR of the feed motor 41 vary depending on the temperature, and may be corrected.

  The current subtracting unit 103 calculates a tension current Ic (k) obtained by subtracting the reference current Ib (k) from the feed current Ia (k). Then, the current subtraction unit 103 calculates an average tension current Id that is an average value of the calculated plurality of tension currents Ic (k) and a peak tension current Ie that is the maximum value of the plurality of tension currents Ic (k). To do. The calculated average tension current Id and peak tension current Ie are input to the current tension converter 104.

The current tension converter 104 calculates the average tension Td based on the average tension current Id, and calculates the peak tension Te based on the peak tension current Ie. The average tension Td and the peak tension Te can be obtained from the equations (4) and (5), respectively.
Td = Id × Kt × Z / Rk (4)
Te = Ie × Kt × Z / Rk (5)
Kt is a torque constant of the feed motor 41, Z is a reduction ratio of the feed motor 41, and Rk is a radius of the drive roller 31a.

Further, the current tension conversion unit 104 calculates the detected tension Tc by the equation (6).
Tc = {P × Td / (P + Q)} + {Q × Te / (P + Q)} (6)
P and Q are arbitrary constants for weighting the average tension Td and the peak tension Te with respect to the detected tension Tc.

  The tension subtraction unit 105 is a tension error Tf (n) that is an error between the detected tension Tc (n−1) output from the current tension conversion unit 104 and the target tension Ta (n) commanded from the main control unit 81. Is calculated. The value in parentheses means the number of feeding operations. For example, Ta (n) means the target tension Ta at the n-th feeding operation. The same applies hereinafter.

The tension correction amount calculation unit 106 calculates a tension error integrated value Tg (n) obtained by integrating the tension error Tf (n) output from the tension subtraction unit 105 according to the equation (7). Further, the tension correction amount calculation unit 106 calculates the tension correction amount Th (n) using equation (8).
Tg (n) = Tg (n-1) + Tf (n) (7)
Th (n) = Tg (n) × G (8)
Here, G is a gain.
The tension error integrated value Tg is initialized, that is, cleared to 0, triggered by mounting of the roll body R or acceptance of a print job execution command.

  The tension adding unit 107 adds the tension correction amount Th (n) output from the tension correction amount calculating unit 106 to the target tension Ta (n) instructed from the main control unit 81 to obtain the target tension Ta (n). Correct. Then, the corrected target tension Ta (n) is output to the motor output value calculation unit 91.

  When the printing process is performed, the target tension Ta (n) at the n-th feeding operation is set by the target tension correction unit 92 in this way, and the detected tension Tc (at the (n-1) -th previous feeding operation). While performing the correction based on n-1), the n-th feeding operation is executed based on the corrected target tension (tension feedback control). During the printing process, such a feeding operation with tension feedback control is repeated intermittently (intermittently) at a specified feeding speed and feeding distance with a time interval corresponding to the printing operation.

By the way, if a plurality of feeding operations with tension feedback control are all performed during the printing process, as shown in FIG. 5, the first several feeding operations do not stabilize the tension of the printing medium A, and paper feeding is not performed. The problem of instability arises. Therefore, in the present embodiment, as shown in FIG. 6, immediately before the printing process, a pseudo-feed process (pseudo-feed step) in which the feed operation for feedback is performed three times is executed, and the print medium in the feed operation during the print process is performed. The tension of A is stabilized.
In the present embodiment, the pseudo-feed process is executed during the cueing process (cueing step) performed in the printing process preparation operation. Here, referring to FIG. The pseudo-feed process will be described. The print processing preparation operation is performed for each print job, and is performed immediately before the print processing when a print job execution command is received.

  As shown in FIG. 7, in the preparation operation for the printing process, first, the feed motor control unit 82 and the roll motor control unit 84 control the feed motor 41 and the roll motor 51, and the page top of the print page is placed on the feed roller 31. The print medium A is fed so as to come to the nip position (S1). Then, the above reference current measurement operation is executed (S2). That is, the feed motor control unit 82 drives the feed motor 41 and the reference current calculation unit 102 calculates the reference current Ib (k). Here, it is preferable that the reference current measurement operation is performed a plurality of times, and the average value thereof is set as the reference current Ib (k).

  When the reference current measurement operation is completed, a cueing process is performed in which the front end of the page is moved to the position of the discharge nozzle at the upstream end in the paper feed direction of the print head 21 (hereinafter, the upstream end nozzle position) (S3 and S4). Specifically, first, the print medium A is placed by the feed motor control unit 82 and the roll motor control unit 84 so that the leading edge of the page comes to a position upstream from the upstream end nozzle position by the feed distance to be sent during the pseudo feed process. Send (S3). When the leading edge of the page is positioned upstream of the movement position in the paper feed direction, the feed motor 41 and the roll motor 51 are driven to rotate forward to feed the print medium A in the paper feed direction. On the other hand, when the page leading edge is located downstream in the paper feeding direction from the moving position, the roll motor 51 is driven in reverse to feed the print medium A in the direction opposite to the paper feeding direction.

  Thereafter, a pseudo feed step is executed (S4). In the pseudo feed step, the feed motor control unit 82 and the roll motor control unit 84 perform three feed operations. The three feeding operations are executed at the same feeding speed and feeding distance as the feeding operation in the printing process so as to be performed in a manner close to that in the printing process. On the other hand, the three feeding operations are executed without a time interval corresponding to the printing operation between the feeding operations in order to shorten the tact time. Through the three feeding operations, the target tension correction unit 92 obtains the detected tension Tc (3) and the tension error Tf (3), and the page leading end reaches the upstream end nozzle position. As a result, the print processing is enabled and the preparation operation is finished.

  As described above, according to the above-described embodiment, the first several feeding operations are performed before the printing process. Therefore, as illustrated in FIG. 8, the tension of the print medium A during the feeding operation is controlled by tension feedback control. The printing process can be performed after the tension becomes stable. That is, because the feed operation during the pseudo-feed process before the print process is fed back and the feed operation during the print process is performed, the tension of the print medium A in the feed operation during the print process can be stabilized. The printing process can be performed stably.

  Also, because the feed operation in the pseudo feed process is executed at the same feed speed and feed distance as the feed operation in the printing process, the feed operation in the pseudo feed process is performed as close as possible to the feed operation in the print process. It can be carried out. As a result, it is possible to obtain the same detected tension Tc as in the feeding operation in the printing process, and to improve the accuracy of tension feedback control.

  Furthermore, since the pseudo-feed process is executed during the cueing process, the pseudo-feed process can be executed immediately before the print process. Therefore, the feed operation in the pseudo feed process can be performed in a state close to the feed operation in the printing process. Therefore, the accuracy of tension feedback control can be further improved.

  Furthermore, in the pseudo-feed process, the tact time can be improved because the feed operation is performed three times without leaving a time interval corresponding to the printing operation.

  In the above-described embodiment, it is preferable that the pseudo-feed process is executed within a predetermined time before starting the printing process. According to such a configuration, the feed operation in the pseudo feed process can be performed in a state close to the feed operation in the printing process. Therefore, the accuracy of tension feedback control can be improved.

  In the above embodiment, the tension feedback control is performed for each print job, and the pseudo feed process is performed for each print job. However, when the conditions such as the feed speed are changed in the print job, A configuration may be employed in which tension feedback control is performed for each section having different conditions, and pseudo feed processing is performed for each section. That is, in such a case, in addition to immediately before the printing process, the pseudo-feeding process is executed when the above conditions during the printing process are changed.

  In the above-described embodiment, the feed operation is executed three times in the pseudo-feed process. However, the number of times is not limited as long as the tension applied to the print medium A is stabilized. That is, a configuration in which the feed operation is executed once or twice in the pseudo-feed processing or a configuration in which the feed operation is performed four or more times in the pseudo-feed processing may be used.

  In the above embodiment, the present invention is applied to the printing apparatus (large format printer 1) that performs printing on the printing medium A that is sent by the medium feeding mechanism 11. However, the present invention is not limited to this. . That is, the present invention may be applied to a medium processing apparatus that performs processing other than printing on a medium that is sent by the medium feeding mechanism 11.

  DESCRIPTION OF SYMBOLS 1 ... Large format printer, 12 ... Printing mechanism, 13 ... Controller, 31 ... Feed roller, 32 ... Roll holding part, 36 ... Feed roller drive part, 38 ... Roll drive part, A ... Print medium, R ... Roll body.

Claims (8)

A holding unit for holding a roll body around which the print medium is wound;
A feed unit that pulls out and sends the print medium from the roll body;
A printing unit for printing on the print medium sent by the sending unit;
A roll driving unit that rotationally drives the roll body via the holding unit in a direction in which the printing medium is sent from the roll body;
A feed drive unit for driving the feed unit;
A feed control unit that controls the feed drive unit and the roll drive unit, and performs a feed operation for feeding the print medium a plurality of times while applying tension to the print medium,
The feed control unit
The target tension at the time of the n (n ≧ 2) feed operation is corrected based on the detected tension at the time of the feed operation before the (n−1) th of the plurality of feed operations, and corrected. Based on the target tension, the n-th feeding operation is controlled,
A printing apparatus that executes a pseudo-feeding step of performing the feeding operation at least once before a printing process in which the printing operation by the printing unit and the feeding operation are alternately performed.   The printing apparatus according to claim 1, wherein the feeding operation in the pseudo feeding step is performed at a feeding speed of the feeding operation in the printing process.   The printing apparatus according to claim 1, wherein the feeding operation in the pseudo feeding step is performed at a feeding distance of the feeding operation in the printing process. The feed control unit executes a cueing step of moving a page tip of the print medium to the printing unit before the printing process,
The printing apparatus according to claim 1, wherein the pseudo-feeding step is executed during the cueing step.   5. The printing apparatus according to claim 1, wherein the pseudo-feeding step is executed within a predetermined time before the start of execution of the printing process.   6. The one or more feeding operations in the pseudo feeding step are performed without a time interval corresponding to the printing operation between the feeding operations. The printing apparatus as described in.   The printing apparatus according to claim 1, wherein the pseudo-feeding step is executed for each print job. A holding unit for holding a roll body around which the print medium is wound;
A feed unit that pulls out and sends the print medium from the roll body;
A printing unit for printing on the print medium sent by the sending unit;
A roll driving unit that rotationally drives the roll body via the holding unit in a direction in which the printing medium is sent from the roll body;
A feed drive unit that drives the feed unit, and controls the feed drive unit and the roll drive unit to perform a feed operation of feeding the print medium a plurality of times while applying tension to the print medium. A control method,
The target tension at the time of the feeding operation of n (n ≧ 2) times is corrected based on the detected tension at the time of the feeding operation before the (n−1) th time among the plurality of feeding operations, and corrected. Based on the target tension, the n-th feeding operation is controlled,
A printing apparatus control method, comprising: performing a pseudo-feeding step of performing the feeding operation at least once before a printing process in which the printing operation by the printing unit and the feeding operation are alternately performed.

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