JP5963492B2 - Conveying apparatus and recording apparatus - Google Patents

Description

  The present invention relates to a transport apparatus having stable transport accuracy.

  In conventional large-sized ink jet printers, corresponding roll-shaped recording media (hereinafter referred to as roll paper) have a wide range of roll widths and types and materials of recording media. The roll paper is held by being set on a spool, and the roll paper is conveyed while being sandwiched between a conveyance roller and a pinch roller which is a driven roller. At this time, if the tension of the roll paper changes, the roll paper feeding accuracy is disturbed and the image quality deteriorates.

  Japanese Patent Application Laid-Open No. 2004-228561 discloses a transport device that is controlled so that a certain set tension is applied to the roll paper during printing so that such roll paper transport failure and appearance failure do not occur. The transport device consists of a motor that rotates a spool that supports the roll paper, a transport roller that sandwiches and transports the paper drawn from the roll paper, and tension that generates a constant tension regardless of changes in the roll paper diameter. Part. After measuring the mechanical load and calculating the tension required for the roll paper, the roll paper radius is estimated and the torque applied to the motor is calculated. The back tension of the roll paper is made constant by applying torque to the motor that drives the spool.

JP 2009-208921 A

  However, in a printer that intermittently conveys roll paper, inertia occurs after rotation of the roll paper, so that the roll paper is temporarily slack after the intermittent conveyance by the conveyance roller is stopped. In this case, adjustment is performed by the roll paper rewinding operation so that a certain tension is applied to the roll paper after the conveyance roller is stopped. An image is recorded on a recording medium by a reciprocating motion in the main scanning direction of the carriage on which the printing unit is mounted. However, when the printing width is short relative to the recording medium, the interval between the reciprocating movements of the carriage is shortened and printing is performed. The stop time of the transport roller inside becomes shorter. If the roll paper becomes slack due to the inertia generated in the roll paper at this time and the roll paper is rewound, the roll paper for the next printing is carried out by the transport roller before the roll paper stops and the roll paper stops. May need to be transported.

  As described above, if the roll paper rewinding operation is not completed before the next intermittent conveyance start of the conveyance roller, the following occurs. That is, the inertia applied to the roll paper, the torque applied to the roll paper due to the rewinding operation, and the conveyance force for feeding the roll paper to the printing unit by the conveyance roller (or conveyance motor) overlap, so that abnormal tension is instantaneously generated. Occurs. In such a case, since the back tension of the roll paper for each conveyance is not uniform, the conveyance accuracy may be disturbed. When a stepping motor is used as the conveyance motor, there is a possibility that the step-out occurs in the conveyance motor, and there is a concern that the print quality may be deteriorated due to disturbance in the conveyance accuracy. If transport is performed in this state, a large transport sound may be generated by pulling the roll paper at the start of transport.

  An object of the present invention is to provide a transport device capable of rewinding the slack that occurs in the roll paper due to inertia each time intermittent transport of the transport roller stops, within the stop time of the transport roller.

The transport device of the present invention includes a transport roller that intermittently transports roll paper in the transport direction, a paper feed unit that feeds the roll paper toward the transport roller, and a paper feed motor that drives the paper feed unit. The first intermittent transport by applying a driving torque in a direction opposite to the transport direction to the paper feeding motor before the second intermittent transport operation following the first intermittent transport operation by the transport roller. A conveying device that performs a rewinding operation for rewinding the slack of the roll paper generated between the paper feeding unit and the conveying roller by an operation, wherein the first intermittent conveying operation and the second intermittent conveying operation A predicting means for predicting a stop time during the rewinding operation, and in the rewinding operation, when the stop time predicted by the predicting means is equal to or longer than a predetermined time, a driving torque having a first value in a direction opposite to the conveying direction is used. Drive the paper feed motor Is allowed, if the stop time is less than the predetermined time of the present invention and a drive control means for driving the paper feed motor in the driving torque of the second value larger than the first value in the opposite direction The recording apparatus includes a carriage mounted with a recording head for recording an image and capable of reciprocating in a main scanning direction intersecting the transport direction, and the transport apparatus.

  According to the present invention, it is possible to provide a transport device capable of rewinding the slack generated in the roll paper due to inertia each time the intermittent transport of the transport roller is stopped within the stop time of the transport roller.

  In the transport apparatus of the present invention, the slack of the roll paper can be rewound within the stop time of the transport roller, and the roll paper can be transported stably.

FIG. 3 is a cross-sectional view of a recording apparatus including a roll paper transport device according to the present invention. It is a top view of the spool of roll paper concerning the present invention. It is a speed-torque relationship diagram in the paper feed / conveyance section according to the present invention. 1 is an overall block diagram of a sheet feeding / conveying unit according to the present invention. It is a speed-torque relationship diagram according to the present invention. It is a speed-torque relationship diagram according to the present invention. It is a flowchart of roll paper load switching concerning a 1st embodiment. It is a flowchart of roll paper load switching concerning a 2nd embodiment.

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

  FIG. 1 is a cross-sectional view showing a schematic configuration of an ink jet printer which is an example of a recording apparatus provided with a roll paper R transport device according to the present invention. In the figure, reference numeral 1 denotes an ink jet printer apparatus main body, and 7 denotes an image recording unit. The image recording unit includes a recording head and a carriage 8 on which the recording head is mounted. A sheet sensor that can detect the presence or absence of a sheet and the edge of the sheet is disposed on the side surface of the carriage 8, and the width of the sheet can be detected by reciprocating the carriage 8. This recording head has a plurality of nozzle rows (not shown) in the sub-scanning direction of the surface facing the printing surface, and discharges ink of different colors for each nozzle row. The recording head is supplied with ink of each color from an ink tank via a supply tube to each color nozzle. Further, the carriage 8 is supported at both ends by being fixed to the frame of the ink jet printer main body 1 and slidable along a guide shaft 9 and a guide rail (not shown) arranged in parallel to each other. An image is recorded on the sheet by ejecting ink from the recording head while reciprocating the carriage 8 toward the sheet conveyed to the printing unit. The carriage 8 can be reciprocated by a linear encoder (not shown), a belt driving device, and a carriage motor. The roll paper R set on the spool 2 passes through between the intermediate roller 3a and the driven roller 3b in the nip-released state via the conveyance path, and detects a sheet (not shown) in front of the conveyance roller 4. Sent to the means. When the paper is detected by this paper detection means, the pendulum arm 3 having the intermediate roller 3a rotates, the roll paper R is nipped by the opposed driven roller 3b, and the paper is automatically fed to the transport roller 4. I will pay out. The roll paper R is conveyed to a platen 6 provided at a recording position facing the recording head while being sandwiched between the conveying roller 4 and the pinch roller 5. When the leading edge of the roll paper R reaches the platen 6, the pendulum arm 3 having the intermediate roller 3a rotates in the reverse direction to release the nip of the intermediate roller 3a. In the subsequent transport operation of the roll paper R, the force generated on the spool shaft is dominant as the acting force on the roll paper R.

  FIG. 2 is a top view of the spool 2 of the roll paper R. FIG. The roll paper R passes the spool 2 through the paper tube at the winding center thereof, and the roll paper holders 10 and 11 are fixed to the spool 2 so as not to rotate. The spool 2 is rotatably supported by the printer main body, and thus the roll paper R is also rotatably held. Reference numeral 12 denotes a paper feed motor that applies a driving force to the roll paper R, reference numerals 13 to 15 denote a gear train that transmits the driving force of the paper feed motor 12 to the roll paper R, and reference numeral 16 denotes a paper feed encoder.

  FIG. 3 is a diagram showing the relationship between the transport roller 4 that forms the main part of the paper feed / transport section according to the present invention, the torque generated by the roll paper R, the transport speed, and the like. The driving torque of the transport roller 4 is Tlf, the driving torque of the roll paper R is Troll, and the load force applied to the recording paper between the transport roller 4 and the roll paper R is Tpap. Also, the conveyance speed (circumferential speed) of the conveyance roller 4 is Vlf, the conveyance speed (circumferential speed) of the roll paper R is Vroll, and the recording paper conveyance speed is Vpap. The rotation directions of torque Tlf and Troll, which are the forces of the rotating system, are defined by the arrow directions represented by CCW (counterclockwise) and CW (clockwise) in FIG. Here, since the case where the roll paper R rotates counterclockwise is considered, the CCW direction is the same as the rotation direction of the roll paper R, and the CW direction is the opposite direction to the rotation direction of the roll paper R. For Tpap, Vlf, Vroll, and Vpap, the direction of the arrow in FIG. 3 is a positive value. In the waveform diagrams shown below, the direction shown in FIG. 3 is used as a reference.

  FIG. 4 is an overall block diagram of the paper feeding / conveying unit according to the present invention. The control block includes a first control unit that controls driving of the transport motor 24 and a second control unit that controls driving of the paper feed motor 12.

The first control unit receives the transport encoder information 26 and outputs a transport operation information 30 and a PWM (Pulse Width Modulation) value 40 that is an operation amount to the motor driver 31. A control calculation is performed in the conveyance control unit 23 from the difference value between the conveyance encoder information 26 detected from the conveyance encoder 25 connected to the conveyance roller 4 and the conveyance operation target, and the PWM value 40 is determined. The PWM value 40 is input to the motor driver 31 to drive and control the conveyance motor 24. The transport motor 24 is a drive source that drives the transport roller 4.
Further, the conveyance control unit 23 outputs conveyance operation information 30 including a series of operation information such as the driving start timing of the conveyance motor 24 and the position / speed of the conveyance roller 4 to the paper feed motor control unit 22.

  The second control means inputs the conveyance load torque setting value 21, the standby load torque setting value 42, the conveyance operation information 30, the current value 35, the paper feed encoder information 27, and the roll paper information 39 to the motor driver 32. The PWM value 34 that is the operation amount is output.

  The conveyance load torque setting value 21 and the standby load torque setting value 42 include roll paper information 39 which is information such as the winding diameter, paper width, and paper type of the roll paper R to be conveyed. And it is inputted to the standby load torque table 38 and determined. The roll paper information 39 is a value set in the roll paper information storage area 41 before the operation.

  In the paper feed motor control unit 22, the torque setting values 43, 44, 45, and 47 are selectively corrected by the conveyance operation information 30 with the conveyance load torque setting value 21 and the standby load torque setting value 42 as reference values. It is used for value calculation, and finally a current value 36 is output. Here, the torque setting value 43 is an output value from the roll paper acceleration correction value generation unit 48, and the torque setting value 44 is an output value from the roll paper deceleration correction value generation unit 49. Further, the torque setting value 45 is an output value from the sheet feeding portion vibration suppression value generating unit 50, and the torque setting value 47 is an output value from the mechanical reference load value 46.

  The paper feed motor 12 to be operated is driven by a motor driver 32 of a PWM control system. The PWM control system motor driver 32 does not guarantee a flowing current value. In order to check the current value flowing into the motor driver 32, the current value 35 is detected by the current detection circuit 33, and the PWM value 34 that is the output value is adjusted according to the difference value between the current value 36 and the detected current value 35. A control unit 37 is formed.

  A series of processing units including the paper feed motor control unit 22 and the current feedback control unit 37 serve as a second control unit.

  FIG. 5 is a diagram showing temporal changes in various quantities when the configuration of FIG. 4 is applied to an actual transport operation. That is, the conveying speed (circumferential speed) Vlf and driving torque Tlf of the conveying roller 4, the conveying speed (circumferential speed) Vroll and driving torque Troll of the roll paper R, and the conveying roller 4 and the roll paper R The time change of the load force Tpap applied to the recording paper during the period is shown. The conveyance speed Vpap of the recording paper is equal to Vlf. In FIG. 5, the relationship between the time t2 when Vlf = 0, which is the stop time for intermittent conveyance of the conveyance roller 4, and t3, which is the time required for the roll paper R to stop between the conveyance roller stops, is t2> t3. . This indicates that the inertia of the roll paper R is a control state in stable conveyance that does not affect the conveyance accuracy of the conveyance roller 4.

  In an actual system, there are a paper slack phenomenon between the transport roller 4 and the roll paper R, a mechanical load of the transport mechanism to be operated, and the like. Taking these into account, the Troll value is calculated based on the block diagram of FIG. 4, thereby realizing an ideal Tpap. First, using the operation information of Vlf, the first period (0 to B) from the acceleration start to the deceleration start of the transport roller 4, the second period (B to C) from the deceleration start to the stop, and the restart from the stop. The period until the start of acceleration is the third period (C to D).

  In the first period (0 to B), the conveyance load torque set value 21 that is constantly given is the reference value of Troll. A torque set value 43 that is an output value from the roll paper acceleration correction value generation unit 48 and a torque set value 45 that is an output value from the paper feed unit vibration suppression value generation unit 50 are added to this value, and the mechanical reference load value is obtained. A value obtained by subtracting the torque set value 47, which is an output value from 46, becomes Troll. The standby load torque set value 42 is equal to zero. In the roll paper acceleration correction value generation unit 48, the torque setting value 43 corresponding to the acceleration of the roll paper R is obtained using the acceleration of the transport roller 4 and the roll paper information 39. Further, the paper feed unit vibration suppression value generation unit 50 uses the speed information of the transport roller 4 to obtain a torque setting value 45 that acts to suppress the vibration phenomenon of the paper feed unit 20. Since the torque set value 47, which is an output value from the mechanical reference load value 46, is a load value that the drive system itself originally has, from the transport load torque set value 21 that is the load force that the roll paper R wants to generate. Subtraction is performed and the remainder is generated as a load by the paper feed motor 12.

  Between times A and B in which the transport roller 4 is in a constant speed region, Troll has a set value a corresponding to the transport load torque set value 21 to the torque set value 47, and this is the load force that is a target value that is continuously applied to Tpap. x. At times 0 to A in the acceleration region, torque set values 43 and 45 are added based on the set value a so as to compensate for the roll paper acceleration inertia, and the maximum value of the set value is b. Since the acceleration of the transport roller 4 is non-zero at time 0 to A, the torque setting value 43 also shows a non-zero value. Since the acceleration of the transport roller 4 is 0 in the region where the transport roller 4 is at a constant speed from time A to time B, it is not necessary to perform calculation in consideration of acceleration and constant speed. In FIG. 5, the conveyance load torque setting value 21 is a case where it has a larger negative value than the torque setting value 47, so the setting value a is an example in which the value is in the CW direction. Depending on circumstances, it may be a value in the CCW direction. Finally, it is converted into a current value corresponding to Troll as a command value to the motor. This is determined from the motor specifications and the mechanical transmission mechanism.

As a result, the extra load fluctuation accompanying the acceleration is canceled out, and in the first period from time 0 to B, Tpap indicates the load force x having a constant value, and the back tension is expected to be stabilized. Here, consider the relationship with the driving torque Tlf of the conveying roller 4. Tlf includes all mechanical loads applied to the transport drive system, and transports the roll paper R in the transport direction in which Vlf assumes a positive value. Therefore, the required torque is always in the CCW direction at least in a steady region that is not accompanied by acceleration / deceleration. On the other hand, Troll is in the CW direction because it is necessary to apply a constant load to the transport roller 4 at least in a steady region where acceleration / deceleration is not involved. That is, when the conveying roller 4 is in the constant speed region, the relationship of Tlf> Troll (set value lf> set value a in FIG. 5) is satisfied. On the basis of this relationship, necessary inertia is added to each of the transport roller 4 and the roll paper R in the acceleration / deceleration region.

  Even if Tpap is constant, Vlf and Vroll do not always match due to the influence of the paper path between the transport roller 4 and the roll paper R. FIG. 5 also shows how the roll paper R moves with some delay time t1.

  Even in the second period (B to C), the conveyance load torque set value 21 that is constantly given becomes the reference value of Troll. A torque setting value 44 that is an output value from the roll paper deceleration correction value generation unit 49 and a torque setting value 45 that is an output value from the paper feed unit vibration suppression value generation unit 50 are added to this value, and the mechanical reference load is added. A value obtained by subtracting the torque setting value 47, which is an output value from the value 46, becomes Troll. The standby load torque set value 42 is equal to zero. The roll paper deceleration correction value generation unit 49 obtains a torque setting value 44 corresponding to the roll paper deceleration inertia amount using the acceleration (during deceleration) of the transport roller 4 and the roll paper information 39.

  Since the transport roller 4 is in the deceleration region, the torque is set to the CW side by adding the torque setting values 44 and 45 with the setting value a as a reference so as to compensate for the roll paper deceleration inertia. The maximum value is c. As a result, the extra load fluctuation accompanying the deceleration is canceled out, and Tpap indicates the load force x that is a constant value in the second period from time B to time C, and the back tension is expected to be stabilized. However, there may be a case where slight paper slack occurs due to inconsistency between Vlf and Vroll. FIG. 5 also shows that Tpap is small because some slack is generated.

  In the third period (C to D), a value obtained by adding a torque setting value 47 that is an output value from the mechanical reference load value 46 to the standby load torque setting value 42 is the setting value d of Troll. Since the mechanical reference load value 46 is a load value inherent in the drive system itself, in order to move the roll paper R independently, it is necessary to compensate in addition to the standby load torque setting value 42. There is. The conveyance load torque set value 21 is equal to zero.

  In the third period, the roll paper R can move in the direction of rewinding by the amount of slackness of the roll paper R generated until the end of the second period. FIG. 5 also shows a state in which a small amount of slack during operation is rewound and eliminated in the third period, and the waveform of the speed Vroll of the roll paper R also shows a negative value in order to eliminate the slack. It will be. At time E, the slack is completely eliminated, and after that, Tpap applies tension to the roll paper R with a load force y that is a minute pulling force. As a result, even if slack occurs during the conveyance, it is expected that the conveyance can be started under the same condition as the operation of the first conveyance roller 4 at the start of the next operation. In the third period, after the maximum time necessary for eliminating paper slack obtained experimentally in advance has elapsed, from the viewpoint of safety related to motor heat generation and reduction of power consumption, the paper feed motor 12 It is good also as composition which can turn off output of generated torque.

  FIG. 6 shows that the setting value of Troll in the second period is switched to f under the printing condition (t2 <t3) where the stop time t2 of the transport roller 4 is shorter than the time t3 until the slack removal of the roll paper R is completed. It is a speed-torque relationship diagram at the time. Regarding the torque Troll to the roll paper R, the torque setting value in the CW direction (the direction opposite to the rotation direction of the roll paper R) in the second period is changed from the first value c to a second value f that is a larger value. By switching, the reduction in the rotational speed of the roll paper R is increased. By doing so, control is performed so that the slack removal of the roll paper R is completed at a time t4 shorter than the stop time t2 of the conveying roller 4 (t4 <t2). Thereby, it becomes possible to perform stable conveyance at the time of the next intermittent conveyance by the conveyance roller 4.

  Note that control may be performed by switching a plurality of setting values, such as changing not only the setting value of Troll in the second period but also setting value of Troll in the third period from d to g.

  FIG. 7 is a flowchart when the behavior of the transport roller 4 is predicted and the second control unit is set. After the print data is received by the printer in step S1, the estimated stop time τ2 of the transport roller 4 in the intermittent transport is calculated from the print data such as the paper size and the scan width of the recording head by the carriage 8 in step S2. Next, τ3, which is a threshold value for the roll paper slack removal time set in advance in step S3, is read. In step S4, τ2 and τ3 are compared, and if the estimated time τ2 is larger than the threshold τ3, the roll is stopped while the conveying roller 4 is stopped by the torque set value c for the roll paper R, which is a normal stable control value, in step S5. The slack of the paper R is removed. When the estimated time τ2 is smaller than the threshold value τ3, the torque set value is changed to f as in step S6, and control is performed so that the slack removal of the roll paper R is completed within the conveyance roller stop time. In step S7, the roll paper is conveyed and printing is performed by the recording head while performing slack removal control. In step S8, the presence / absence of the next print data is confirmed. If there is print data, steps S2 to S7 are repeatedly executed, and if there is no print data, printing is terminated.

  In this embodiment, the estimated stop time τ2 of the conveyance roller 4 and the threshold value τ3 of the roll paper slack removal time are compared for each conveyance, and the torque setting value Troll of the roll paper R is switched based on the result. Here, the value to be switched is not limited to only the deceleration torque of the roll paper R, and the stop control of the roll paper R may be performed by changing other set values. In addition, the threshold value τ3 for executing this switching and the deceleration torque setting value of the roll paper R may be changed in accordance with the paper type of the roll paper R set in the paper supply unit 20, the paper size, and the like. Further, the threshold value τ3 may be controlled in comparison with the estimated stop time τ2 of the transport roller 4 while being changed according to the change in the winding diameter of the roll paper R set in the paper supply unit 20.

  FIG. 8 is a flowchart when setting the second control means by predicting the behavior of the carriage 8 according to the second embodiment of the present invention. If the reciprocating movement time of the carriage 8 in the main scanning direction is sufficient, the control of the transport roller 4 performing intermittent transport and the load torque control to the roll paper R are finished. Therefore, the time τ2 during which the conveying roller 4 is stopped is replaced with a one-way reciprocation movement time τ4 in the main scanning direction of the carriage, and is compared with a carriage movement time τ5 that is a preset threshold value.

  After the print data is received by the printer in step S11, in step S12, a reciprocation movement time τ4 in the main scanning direction is estimated from the paper size and the scan width of the recording head by the carriage. Next, the carriage main scanning time τ5 at which the roll paper slack removal that has been set in advance in step S13 can be finished is read. In step S14, τ4 and τ5 are compared, and if the estimated time τ4 is larger than the threshold τ5, the conveying roller 4 is stopped at step S15 by the torque set value c ′ for the roll paper R, which is a normal stability control value. The slack of the roll paper R is removed. If the estimated time τ4 is smaller than the threshold τ5, the torque set value is changed to f ′ in step S16, and control is performed so that the slack removal of the roll paper R is completed within the stop time of the conveying roller 4. In step S17, the roll paper R is conveyed and printing is performed by the recording head while performing slack removal control. In step S18, the presence / absence of the next print data is confirmed. If there is print data, step S12 to step S17 are repeatedly executed, and if there is no print data, printing is terminated.

  Similarly to the first embodiment, in this embodiment, the value to be changed for slack removal is not limited to the deceleration torque of the roll paper R, but the roll paper R can be stopped by changing other set values. Control may be performed. Further, the threshold value for executing this switching and the deceleration torque setting value of the roll paper R may be changed in accordance with the paper type, paper size, etc. of the roll paper R set in the paper supply unit 20.

2 Spool 4 Transport roller 12 Paper feed motor 20 Paper feed unit R Roll paper

Claims (6)

A transport roller for intermittently transporting roll paper in the transport direction;
A paper feed unit that feeds roll paper toward the transport roller;
A paper feed motor for driving the paper feed unit,
Before the second intermittent transport operation following the first intermittent transport operation by the transport roller, by applying a driving torque in the direction opposite to the transport direction to the paper feed motor, the first intermittent transport operation A transporting device that performs a rewinding operation for rewinding a slack of roll paper generated between the paper feeding unit and the transporting roller;
Predicting means for predicting a stop time between the first intermittent transfer operation and the second intermittent transfer operation;
In the rewinding operation, when the stop time predicted by the prediction unit is equal to or longer than a predetermined time, the paper feed motor is driven with a driving torque having a first value in a direction opposite to the transport direction, and the stop time is And a drive control means for driving the paper feed motor in the reverse direction with a drive torque having a second value larger than the first value when the time is less than the predetermined time . Depending on the winding diameter of the roll paper, the transport apparatus according to claim 1, characterized in that for changing the predetermined time. The paper feed unit, the conveying apparatus according to claim 1 or 2, characterized in that it is intermittently driven in synchronism with the conveying roller. A carriage mounted with a recording head for recording an image and capable of reciprocating in the main scanning direction intersecting the transport direction;
Recording apparatus characterized by comprising a transport device according to any one of claims 1 to 3. The recording apparatus according to claim 4 , wherein the predicting unit predicts the stop time from information on a paper size included in the received print data and scanning width of the recording head by the carriage. Said predicting means, a recording apparatus according to claim 4 or 5, characterized in that predicting the stop time from a round-trip travel time of the carriage.

Images