JP2008087874A - Printer and method for controlling printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printer capable of transmitting power of a motor for driving a planetary gear to a driven part properly. <P>SOLUTION: This printer is provided with the driven part 32, the motor 38 for driving the driven part 32, a driving gear 39, a driven gear 41, a planetary gear part 40 composed of a sun gear, the planetary gear, etc., a detector 31 for detecting a condition of the driven part 32, and a control part 60 for controlling the motor 38. A motor driving part 63 constituting the control part 60 drives the motor 38 to increase driving torque of the motor 38 from first predetermined set torque up to second predetermined set torque until a condition detection part 62 detects a target stop condition of the driven part 32 based on output signals from the detector 31 and drives the motor again by smaller driving torque than the second set torque when the target stop condition cannot be detected even if the motor is driven by the second set torque. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a printer and a printer control method.

  A printer having a platen gap adjusting device that adjusts a gap (gap) between a print head that discharges ink droplets and a platen that faces the ink discharge surface of the print head, as an inkjet printer that performs printing on a print medium such as printing paper Is known (see, for example, Patent Document 1). In the printer described in Patent Document 1, an eccentric cam having three different radii is rotationally driven by a DC motor, and the rotation of the eccentric cam causes the height of the carriage on which the print head is mounted (specifically, The platen gap is adjusted by changing the height of the guide shaft that guides the carriage.

  The printer described in Patent Document 1 includes a detection plate that rotates together with an eccentric cam and an optical sensor that detects the detection plate in order to set the height of the carriage at a position where the platen gap becomes a predetermined amount. I have. The detection plate is a disk-shaped member having a flag that protrudes outward in the radial direction and is formed at a position corresponding to the set height of the carriage. Further, the optical sensor is disposed at a position where the flag of the detection plate is detected. In the printer described in Patent Document 1, the motor is decelerated after the end of the flag corresponding to the carriage height to be set is detected by the optical sensor, and is stopped in a range where the flag is detected. The platen gap is set to a predetermined amount. Further, the motor that rotationally drives the eccentric cam is driven so that the driving torque of the motor is increased stepwise in order to prevent overacceleration of the motor and ensure the stopping accuracy of the eccentric cam.

  Further, as a printer for printing on printing paper, a roll paper equipped with a sun gear attached to a motor shaft and a planetary gear that meshes with the sun gear and is rotatable about the rotation center of the sun gear. A printer is known (for example, see Patent Document 2). In this printer, the driven gear and the planetary gear for rotating and driving the conveyance roller for the printing paper are engaged and disconnected, and the driven gear and the planetary gear for moving the cutter unit for cutting the printing paper are engaged and disconnected. Is possible. That is, in the printer described in Patent Document 2, by using the sun gear and the planetary gear, it becomes possible to drive the two driven parts of the conveyance roller and the cutter unit with one motor. Yes.

JP 2005-103835 A JP 2003-118189 A

  As described in Patent Document 1, when the motor is driven such that the motor driving torque is gradually increased, the motor is prevented from being overaccelerated, and the motor stopping accuracy (that is, driven) It is possible to ensure the stopping accuracy of the eccentric cam as a part. On the other hand, when a planetary gear is used as in the printer described in Patent Document 2, two driven parts can be operated by one motor, and the configuration of the printer can be simplified. It becomes. However, specific means for appropriately controlling the motor that drives the planetary gear and appropriately transmitting the power of the motor to the driven part while using the control method described in Patent Document 1 is disclosed in Patent Document 1 and Patent Document 2 are not disclosed.

  Therefore, the problem of the present invention is to ensure the stopping accuracy of the driven part and to supply the power of the motor for driving the planetary gear to the driven part even when the configuration is simplified using the planetary gear. An object of the present invention is to provide a printer having a configuration capable of appropriately transmitting. Another object of the present invention is to secure the stopping accuracy of the driven part and to drive the power of the motor for driving the planetary gear even when the configuration of the printer is simplified using the planetary gear. It is an object of the present invention to provide a printer control method capable of appropriately transmitting to a printer.

  In order to solve the above problems, a printer of the present invention includes a driven unit that is driven to perform printing on a printing medium, a motor that drives the driven unit, a driving gear that is coupled to the motor, and a driven unit. A driven gear coupled to the drive unit, a sun gear meshed with the drive gear, a planetary gear meshed with the sun gear and meshed with the driven gear, a planetary gear rotatably held and a planetary gear driven by a motor A holding member that can rotate in the occlusal direction of the driven gear and the planetary gear together around the rotation center of the sun gear, and a clutch means that can use the frictional force and stop the power transmission of the motor to the holding member; A detection device for detecting the state of the driven unit disposed on the driven unit side of the planetary gear in the direction of power transmission from the motor to the driven unit, and a control unit for controlling the motor, Detection equipment A state detection unit for detecting a target stop state of the driven unit based on an output signal from the motor, and a motor drive torque from a predetermined first set torque to a predetermined second until the state detection unit detects the target stop state. When the motor is driven so as to increase to the set torque and the state detection unit cannot detect the target stop state even when driven with the second set torque, the motor is again driven with a drive torque smaller than the second set torque. And a motor drive unit for driving.

  Since the printer of the present invention includes the sun gear and the planetary gear, the two driven parts can be driven by a single motor, and the configuration can be simplified. In the present invention, the motor drive unit increases the drive torque of the motor from the predetermined first set torque to the predetermined second set torque until the state detection unit detects the target stop state of the driven unit. In addition, since the motor is driven, it is possible to prevent the motor from being over-accelerated and to ensure the stopping accuracy of the driven part. Furthermore, in the present invention, since the clutch means capable of stopping the power transmission of the motor to the holding member is provided, the motor, sun gear, planetary gear, etc. Even if an overload occurs, damage to the motor, the sun gear, the planetary gear, etc. can be prevented.

  Here, depending on the stop state before the engagement of the driven gear to which the power of the planetary gear is transmitted, the driven gear and the planetary gear may not be properly engaged at the time of engagement. Therefore, the driven gear and the planetary gear are not properly meshed with each other, so that slip occurs in the clutch means, the power transmission of the motor to the holding member is stopped, and the driven gear and the planetary gear are not meshed as they are. Such a situation can occur. In the present invention, the motor drive unit drives the motor again with a drive torque smaller than the second set torque when the state detection unit cannot detect the target stop state even if the motor is driven with the second set torque. Yes. Therefore, even if the clutch means slips and the motor power transmission to the holding member is stopped, the slip is stopped by reducing the motor driving torque, and the motor to the holding member is stopped. It becomes possible to resume power transmission. As a result, the driven gear and the planetary gear can be appropriately meshed, and the power of the motor for driving the planetary gear can be appropriately transmitted to the driven portion.

  In the present invention, it is preferable that the first set torque is a set minimum torque of the drive torque, and the second set torque is a set maximum torque of the drive torque. As described above, when the first set torque is the minimum set torque of the drive torque, the motor is started from a smaller drive torque, so that the motor can be prevented from being over-accelerated more appropriately, and the stop accuracy of the driven part can be prevented. Can be secured. Further, when the second set torque is the set maximum torque of the drive torque, the motor can be driven with a larger drive torque, so that the driven part can be driven even when a large load is applied to the driven part. It becomes possible.

  In the present invention, the motor drive unit increases the motor drive torque from the set minimum torque to the set maximum torque again until the target stop state is detected when the target stop state cannot be detected even when driven at the set maximum torque. It is preferable to drive the motor so as to continue. With this configuration, the motor driving torque can be temporarily reduced to the set minimum torque, so that it is possible to more effectively stop the slipping by the clutch means and resume the transmission of the motor power to the holding member. become.

  In the present invention, it is preferable that the motor drive unit lowers the drive torque of the motor to the set minimum torque without stopping the motor when the target stop state cannot be detected even if driven by the set maximum torque. If comprised in this way, it will become possible to transmit the driving force of a motor to a to-be-driven part earlier. Therefore, for example, it is possible to improve throughput (number of printed sheets per unit time) and the like.

  In the present invention, the driven unit performs, for example, a medium supply hopper on which a print medium before printing is placed, and a multi-feed of the print medium conveyed from the medium supply hopper toward a print area on which the print medium is printed. A print medium supply unit including a multi-feed prevention roller for preventing and a medium return lever for returning a print medium of a specified number or more to the medium supply hopper. As described above, when the driven unit is a print medium supply unit, the medium return lever may not be able to return the print medium to the medium supply hopper depending on the state of the print medium placed on the medium supply hopper. However, in the present invention, when the state detection unit cannot detect the target stop state even when the motor is driven with the set maximum torque, the motor drive unit can drive the motor to the set maximum torque again. The lever allows the print media to be returned to the media supply hopper.

  In order to solve the above problems, the present invention provides a driven unit that is driven to perform printing on a print medium, a motor that drives the driven unit, a driving gear that is connected to the motor, and a driven unit. A driven gear coupled to the drive unit, a sun gear meshed with the drive gear, a planetary gear meshed with the sun gear and meshed with the driven gear, a planetary gear rotatably held and a planetary gear driven by a motor A holding member that can rotate in the occlusal direction of the driven gear and the planetary gear together around the rotation center of the sun gear, and a clutch means that can use the frictional force and stop the power transmission of the motor to the holding member; A printer control method for controlling a printer, comprising: a detection device for detecting a state of a driven part that is arranged on the driven part side of a planetary gear in a direction of power transmission from a motor to a driven part, Drive for driving the motor so as to increase the drive torque of the motor from the predetermined first set torque to the predetermined second set torque until the target stop state of the driven part is detected based on the output signal from the output device And a re-drive step of driving the motor again with a drive torque smaller than the second set torque when the target stop state cannot be detected based on the output signal from the detection device even when driven with the second set torque. It is characterized by providing.

  In the motor control method of the present invention, when the target stop state of the driven part cannot be detected based on the output signal from the detection device even when the motor is driven with the second set torque, the second setting is performed in the re-driving step. The motor is driven again with a driving torque smaller than the torque. Therefore, even if slip occurs in the clutch means and the transmission of the motor power to the holding member is stopped, the slip in the clutch means is stopped by reducing the driving torque of the motor, and the holding member is moved to the holding member. The power transmission of the motor can be resumed. Therefore, the driven gear and the planetary gear can be appropriately meshed with each other. As a result, the configuration of the printer is simplified by providing the sun gear and the planetary gear, and the output signal from the detection device is output in the driving step. Until the target stop state of the driven part is detected, the motor is driven so that the drive torque of the motor is increased from the predetermined set minimum torque to the predetermined set maximum torque, thereby increasing the stop accuracy of the driven part. Even in the case of ensuring, the power of the motor for driving the planetary gear can be appropriately transmitted to the driven part. Further, even if an overload occurs on the motor, the sun gear, the planetary gear, or the like, damage to the motor, the sun gear, the planetary gear, or the like can be prevented by the clutch means.

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

(Schematic configuration of the printer)
FIG. 1 is a side view showing a schematic configuration of a main part of a printer 1 according to an embodiment of the present invention. FIG. 2 is a diagram schematically illustrating a schematic configuration of the drive mechanism 30 and the control unit 60 of the rear sheet feeding unit 32 illustrated in FIG. 1. FIG. 3 is a partial cross-sectional view showing the planetary gear unit 40 shown in FIG. FIG. 4 is a diagram showing the planetary gear unit 40 from the EE direction of FIG. 3. FIGS. 5A and 5B are diagrams for explaining the operation of the rear paper feeding unit 32 shown in FIG. 1. FIG. 5A shows an initial state of the rear paper feeding unit 32, and FIG. A state where the paper can be fed is shown, and (C) shows a state when the printing paper P is returned to the paper feeding hopper 26 by the paper return lever 29. FIG. 6 is a side view showing the position detecting device 31 shown in FIG.

  The printer 1 of the present embodiment is an ink jet printer that performs printing by ejecting ink droplets onto a printing paper P that is a printing medium. Both the front side (left side in FIG. 1) and the rear side (right side in FIG. 1) The printing paper P can be supplied from the side. As shown in FIG. 1, the printer 1 includes a carriage 3 on which a print head 2 that ejects ink droplets is mounted, a PF drive roller 4 for transporting and discharging the printing paper P in the sub-scanning direction SS, and PF Detects the passage of the printing paper P supplied from the driven roller 5, the paper discharge driving roller 6 and the paper discharge driven roller 7, the platen 8 facing the ink ejection surface of the print head 2, a paper feed hopper 26, and the like. A paper detection device 9 that performs printing, a front sheet feeding mechanism 10 for supplying printing paper P from the front side toward a printing area where printing is performed by the print head 2, and a printing paper P from the rear side toward the printing area. And a rear sheet feeding mechanism 11 for feeding. In addition to the printing paper P such as plain paper used for normal document printing, photographic paper used for photo printing, thick paper thicker than plain paper or photographic paper, etc. And transparent films such as OHP sheets.

  The carriage 3 is connected to a CR motor (not shown), is driven by the CR motor, and is guided by the guide shaft 12 to move in the main scanning direction (the direction perpendicular to the paper surface of FIG. 1). The PF drive roller 4 is connected to a PF motor (not shown). The PF driven roller 5 is urged toward the PF driving roller 4 by a spring (not shown) and rotates together with the PF driving roller 4. The paper discharge drive roller 6 is connected to the PF drive roller 4 via a pulley, a belt, etc. (not shown), and rotates at substantially the same peripheral speed as the PF drive roller 4. The paper discharge driven roller 7 is urged toward the paper discharge drive roller 6 by a spring (not shown) and rotates together with the paper discharge drive roller 6. The paper detection device 9 is an optical detection device in which a light emitting element and a light receiving element (not shown) are arranged to face each other in the vertical direction, and one end in the width direction of the printing paper P passing between the light emitting element and the light receiving element. Detect the part.

  The front paper feed mechanism 10 includes a paper feed cassette 20 in which the print paper P supplied from the front side is set, a front paper feed roller 21 that supplies the print paper P in the paper feed cassette 20 to the inside of the printer 1, An arm 22 that rotatably holds the front paper feed roller 21, a transport path 23 through which the printing paper P taken in by the front paper feed roller 21 passes, and a transport drive for transporting the printing paper P that passes through the transport path 23 A roller 24 and a front retard roller 25 for preventing double feeding of the printing paper P (a plurality of printing papers P being supplied into the printer 1 at a time) are provided.

  The front paper feed roller 21 is connected to an ASF motor (not shown) via a planetary gear train (not shown). The arm 22 is configured to be swingable about a rotation shaft 22a, and is urged clockwise in FIG. 1 by an urging member (not shown). The front paper feed roller 21 is attached to the tip of the arm 22 and is in pressure contact with the upper surface of the printing paper P.

  The conveyance drive roller 24 is connected to a PF motor (not shown) that drives the PF drive roller 4 through a gear train (not shown). The front retard roller 25 is a driven roller that is not connected to a driving source for rotation. The front retard roller 25 can be connected to a planetary gear unit 40 described later via a gear train or the like including a cam mechanism and a driven gear 19 (see FIG. 4). The front retard roller 25 can be moved between a position indicated by a solid line and a position indicated by a two-dot chain line in FIG. 1 by power transmitted from an ASF sub motor 38 described later connected to the planetary gear unit 40. ing. That is, when the front retard roller 25 is fed from the front side by the front feed roller 21, as shown by the solid line in FIG. 1, the front retard roller 25 approaches the transport driving roller 24 and feeds from the front side. If not, the transport drive roller 24 is separated. In this embodiment, the front retard roller 25 is a driven unit that is driven to perform printing on the printing paper P. That is, the front retard roller 25 is a driven portion that is driven to supply the printing paper P from the front side.

  The rear paper feeding mechanism 11 feeds a paper feeding hopper 26 as a medium paper feeding hopper on which printing paper P before printing supplied from the rear side is set, and the printing paper P on the paper feeding hopper 26 to the inside of the printer 1. The rear paper feed roller 27 to be supplied (that is, toward the print area), the rear retard roller 28 as a double feed prevention roller for preventing the double feed of the print paper P, and the specified number of print sheets P to be supplied. A paper return lever 29 is provided as a medium return lever for reliably returning the remaining print paper P to the paper feed hopper 26 after the paper has been fed. In this embodiment, the paper feed hopper 26, the rear retard roller 28, and the paper return lever 29 constitute a driven portion that is driven to print on the printing paper P. More specifically, the paper feed hopper 26, the rear retard roller 28, and the paper return lever 29 constitute a rear paper feed unit 32 as a print medium supply unit for feeding the printing paper P from the rear side. .

  The paper feed hopper 26, the rear retard roller 28, and the paper return lever 29 are configured to be swingable as will be described later. Therefore, as schematically shown in FIG. 2, the rear paper feed mechanism 11 includes a drive mechanism 30 for swinging the paper feed hopper 26, the rear retard roller 28 and the paper return lever 29, the paper feed hopper 26, A position detection device 31 as a detection device for detecting the state of the retard roller 28 and the paper return lever 29 is provided. The position detection device 31 is also used to detect the state of the front retard roller 25. Further, a sub motor 38, a drive gear 39, and a planetary gear unit 40, which will be described later, constituting the drive mechanism 30 are also used for driving the front retard roller 25.

  The rear paper feed roller 27 is connected to the ASF motor via a planetary gear train (not shown), like the front paper feed roller 21. In this embodiment, when the ASF motor rotates in one direction by the action of the planetary gear train, the rear paper feeding roller 27 rotates to feed paper from the rear surface side, and when the ASF motor rotates in the other direction, the front paper feeding roller 21 Rotates to feed paper from the front side.

  The paper feed hopper 26 is a plate-like member on which the printing paper P can be placed, and can swing around a rotation shaft 26a provided on the upper end side. Further, in order to prevent double feeding of the printing paper P together with the rear retard roller 28, it is formed of a material having a relatively large friction coefficient, such as cork, at the lower end portion of the loading surface of the printing paper P of the paper feeding hopper 26. A friction member 33 is attached. The rear retard roller 28 is disposed at a position facing diagonally below the rear paper feed roller 27. The outer periphery of the rear retard roller 28 is formed by a member having a large friction coefficient. Further, as shown in FIG. 2, the rear retard roller 28 is rotatably held by an arm 35 that can swing around a predetermined rotation shaft 34. One end portion (the right end portion in FIG. 2) of the arm 35 is in contact with the paper feed hopper 26 while being biased toward the paper feed hopper 26. The paper return lever 29 includes a claw portion 29 a for hooking the lower end of the printing paper P remaining after paper feeding and returning it to the paper feeding hopper 26. Further, as shown in FIG. 2, the paper return lever 29 is configured to be swingable about a predetermined rotation shaft 36. An abutting member 37 that abuts on a later-described second cam 47a is fixed to one end of the rotating shaft 36.

  As schematically shown in FIG. 2, the drive mechanism 30 is connected to a sub motor (ASF sub motor) 38 that drives the rear sheet feeding unit 32 and the sub motor 38 (specifically, fixed to the output shaft of the sub motor 38. A drive gear 39, a planetary gear portion 40 connected to the drive gear 39, and a driven gear 41 connectable to the planetary gear portion 40. The sub motor 38 of this embodiment is a DC motor and is PWM controlled. Further, as shown in FIG. 4, the sub motor 38 is attached to an attachment member 17 attached to a main body frame (not shown) of the printer 1.

  The driven gear 41 of this embodiment includes a first driven gear 42 that can be meshed with a planetary gear 50 that will be described later that constitutes the planetary gear unit 40, a second driven gear 43 that rotates together with the first driven gear 42, and a second driven gear. 43, a fourth driven gear 45 that rotates together with the third gear 44, a fifth driven gear 46 that meshes with the fourth driven gear 45, and a sixth gear that meshes with the fifth driven gear 46. And a driven gear 47. The fourth driven gear 45 is formed with a first cam 45 a that abuts on the paper feed hopper 26 and swings the paper feed hopper 26, and the sixth driven gear 47 abuts on a contact member 37 to return the paper. A second cam 47a for swinging the lever 29 is formed. That is, the driven gear 41 is connected to the rear paper feeding unit 32 via the first cam 45a and the second cam 47a. In this embodiment, when the first cam 45a rotates once, the second cam 47a also rotates once.

  As shown in FIGS. 3 and 4, the planetary gear unit 40 is fixed to a shaft fixing unit 18 a formed on a main body frame (not shown) of the printer 1, and is rotatably held on the fixed shaft 48. A sun gear 49 that meshes with the drive gear 39, a planetary gear 50 that meshes with the sun gear 49 and meshes with the driven gear 42, and a holding member 51 that rotatably holds the planetary gear 50. . The sun gear 49 is inserted through the fixed shaft 48 and rotates around the fixed shaft 48. Further, the holding member 51 is also inserted through the fixed shaft 48 and is rotatable about the fixed shaft 48.

  A fixed shaft 52 on which the planetary gear 50 is rotatably supported is fixed to the holding member 51. At the tip of the fixed shaft 52, a retaining portion 52a that prevents the planetary gear 50 from coming off is formed. The planetary gear 50 is inserted through the fixed shaft 52 and is urged from the holding member 51 side toward the retaining portion 52a by a compression coil spring 53 disposed between the holding member 51 and the planetary gear 50.

  As shown in FIG. 3, a holding member 51 and a sun gear 49 are inserted through the fixed shaft 48 in this order from the shaft fixed portion 18a side. Further, the sun gear 49 and the holding member 51 are pressed against the shaft fixing portion 18 a by the contact portion 17 a formed on the attachment member 17.

  In this embodiment, when the sun gear 49 rotates in a normal state in which no overload or the like is generated in the planetary gear 50, the holding member 51, etc., between the sun gear 49 and the contact portion 17a and between the holding member 51 and Slip occurs between the shaft fixing portion 18 a and the holding member 51 rotates together with the sun gear 49. That is, when the sub-motor 38 is driven and the sun gear 49 rotates in one direction (clockwise in FIG. 4), the holding member 51 rotates about the fixed shaft 48 in the same direction as the sun gear 49, and FIG. As indicated by a broken line, the planetary gear 50 meshes with the first driven gear 42. The power of the sub motor 38 is transmitted to the first driven gear 42 via the sun gear 48 and the planetary gear 50. That is, the power of the sub motor 38 is transmitted to the rear paper feed unit 32. When the sub motor 38 is driven in the reverse direction and the sun gear 49 rotates in the other direction (counterclockwise in FIG. 4), the holding member 51 rotates about the fixed shaft 48 in the same direction as the sun gear 49. As shown by the two-dot chain line in FIG. 4, the planetary gear 50 meshes with the driven gear 19. Then, the power of the sub motor 38 is transmitted to the driven gear 19 through the sun gear 48 and the planetary gear 50. That is, the power of the sub motor 38 is transmitted to the front retard roller 25. Note that the planetary gear 50 does not rotate with respect to the fixed shaft 52 while the holding member 51 rotates together with the sun gear 49.

  On the other hand, when the sun gear 49 rotates in a state where the planetary gear 50, the holding member 51, etc. are overloaded, or in a state where the holding member 51 is locked as will be described later, A slip occurs between the holding member 51 and the power transmission of the sub motor 38 from the sun gear 49 to the holding member 51 is stopped. That is, the sun gear 49 rotates, but the holding member 51 does not rotate. As described above, in this embodiment, the clutch means 54 is configured between the sun gear 49 and the holding member 51 to stop the power transmission of the sub motor 38 to the holding member 51 using the frictional force. When the sub motor 38 is driven in a state where slippage occurs between the side surface of the sun gear 49 and the holding member 51, the planetary gear 50 is fixed to the fixed shaft as the sun gear 49 rotates. Rotate around 52.

  As shown by a broken line in FIG. 4, when the sub motor 38 is driven in a state where the planetary gear 50 is engaged with the first driven gear 42, the sheet feeding hopper 26 rotates the rotation shaft 26a by the rotation of the first cam 45a. Swings to the center. By this swinging, the lower end portion of the paper feed hopper 26 is urged toward the rear paper feed roller 27 or separated from the rear paper feed roller 27. The paper return lever 29 swings around the rotation shaft 36 by the action of the contact member 37 accompanying the rotation of the second cam 47a. By this swinging, the claw portion 29a is retracted at the time of paper feeding or the like, and after feeding, the claw portion 29a is raised and the remaining printing paper P is returned to the paper feeding hopper 26. The arm 35 holding the rear retard roller 28 swings together with the paper feed hopper 26 that swings as the first cam 45a rotates. By this swinging, the rear retard roller 28 is pressed against the rear paper feed roller 27 or separated from the rear paper feed roller 27. That is, the sub motor 38 drives the rear paper feeding section 32 by rotating the first cam 45a and the second cam 47a formed on the driven gear 41.

  Specifically, as shown in FIG. 5A, when the lower end portion of the paper feed hopper 26 and the rear retard roller 28 are lowered and the claw portion 29a of the paper return lever 29 is retracted, the initial state is When the first cam 45a and the second cam 47a are driven by the sub motor 38 and rotated by a predetermined angle from the initial state, the lower end portion of the paper feed hopper 26 rises as shown in FIG. The rear retard roller 28 is also urged toward the paper feed roller 27 and is brought into pressure contact with the rear paper feed roller 27. At this time, the claw portion 29a of the paper return lever 29 remains retracted as in the initial state. This state is a state where paper can be fed. In this state, when the rear paper feeding roller 27 rotates, the top printing paper P among the printing papers P placed on the paper feeding hopper 26 is fed to the rear surface. The paper passes through the pressure contact portion between the paper roller 27 and the rear retard roller 28 and is sent to the paper discharge side. Further, the printing paper P placed on the second and subsequent pages from the top is prevented from being conveyed to the paper discharge side by the action of the rear retard roller 28.

  Further, when the first cam 45a and the second cam 47a are further rotated by a predetermined angle from the state shown in FIG. 5B, the lower end portion of the sheet feeding hopper 26 is lowered as shown in FIG. 5C. The rear retard roller 28 is also lowered and separated from the rear paper feed roller 27. Further, the claw portion 29 a rises and returns the remaining printing paper P to the paper feeding hopper 26. Then, when the first cam 45a and the second cam 47a are further rotated by a predetermined angle from the state shown in FIG. 5B, the initial state shown in FIG. 5A is restored.

  In this embodiment, a claw portion (not shown) formed on the holding member 51 is formed on the third driven gear 44 in the process of shifting from the initial state shown in FIG. 5A to the state shown in FIG. It fits in the cam groove (not shown). Then, in the process of shifting from the state shown in FIG. 5C to the initial state, the claw portion of the holding member 51 is disengaged from the cam groove of the third driven gear 44. When the claw portion of the holding member 51 is fitted in the cam groove of the third driven gear 44, the holding member 51 is locked, and the planetary gear 50 and the first driven gear 42 are always engaged. At this time, slip occurs between the sun gear 49 and the holding member 51, and the power of the sub motor 38 is transmitted to the first driven gear 42 via the sun gear 49 and the planetary gear 50.

  The position detection device 31 is an optical detection device including a detection plate 56 that rotates together with the fifth driven gear 46 and a photosensor 57. The position detection device 31 can detect the rotational positions of the first cam 45a and the second cam 47a, and can also detect the state of the rear paper feed unit 32. In this embodiment, when the first cam 45a and the second cam 47a rotate once, the detection plate 56 also rotates once.

  The detection plate 56 is formed in a thin disk shape as shown in FIG. The detection plate 56 includes three detection portions 56a, 56b, and 56c that protrude outward in the radial direction and are formed with a predetermined interval in the circumferential direction. The detectors 56a, 56b, 56c are formed in this order in the circumferential direction, for example. The photosensor 57 includes a light emitting element and a light receiving element (not shown) that are arranged to face each other so that the detection units 56a to 56c can detect. In this embodiment, an output signal whose signal level changes in a sine wave shape is output from the photosensor 57 depending on whether or not the detectors 56 a to 56 c are between the light receiving element and the light emitting element of the photosensor 57. An output signal from the photosensor 57 (that is, an output signal from the position detection device 31) is input to the control unit 60 that performs various controls of the printer 1.

  In the printer 1 of the present embodiment, during continuous printing in which printing is continuously performed on a plurality of printing papers P, the ink is saved from the rear side in the draft printing mode that saves ink consumption and performs high-speed printing instead of reducing the resolution. When printing the print paper P, the PF drive roller 4 and the paper discharge drive are used for intermittent transport of the print paper P after being transported from the paper feed hopper 26 to the PF drive roller 4 by the rear paper feed roller 27. In addition to the roller 6, a rear paper feed roller 27 is used. That is, in the draft printing mode, the PF driving roller 4 and the paper discharge driving roller 6 driven by a PF motor (not shown) cooperate with the rear paper feeding roller 27 driven by an ASF motor (not shown). Thus, the printing paper P is intermittently conveyed during the printing operation by the carriage 3. Therefore, during continuous printing in the draft printing mode, synchronized control is performed in which the PF drive roller 4, the paper discharge drive roller 6, and the rear paper feed roller 27 are rotated synchronously (that is, at the same peripheral speed). Printing paper P is continuously conveyed.

  Further, during continuous printing in the draft printing mode, as shown in FIG. 5B, until the leading end portion of the last printing sheet P reaches the arrangement position of the PF driving roller 4 and the PF driven roller 5, The lower end portion of the rear sheet feeding hopper 26 and the rear retard roller 28 are always raised.

(Schematic configuration of control unit)
FIG. 7 is a diagram showing a waveform of the state detection signal SG generated based on the output signal from the position detection device 31 shown in FIG. FIG. 8 is a table showing a control table of the sub motor 38 stored in the storage unit 64 shown in FIG. Hereinafter, a schematic configuration of the control unit 60 related to the drive mechanism 30 will be described based on FIG. 2, FIG. 7, FIG.

  As a configuration related to the drive mechanism 30, the control unit 60 includes a detection signal generation unit 61 that generates a state detection signal SG based on an output signal from the position detection device 31, and a rear sheet feeding unit based on the state detection signal SG. A state detection unit 62 that detects the state of 32, a sub motor drive unit 63 as a motor drive unit that drives the sub motor 38, and a storage unit 64 that stores various types of information for driving the sub motor 38. . In addition, a control command unit 65 is connected to the control unit 60 via an input / output unit (not shown).

  Note that the detection signal generation unit 61 and the state detection unit 62 are actually an arithmetic unit such as a CPU, a storage unit such as a ROM, a RAM, and a nonvolatile memory, and an input / output such as an IO port. It is realized by means and the like. In addition, the sub motor drive unit 63 is actually a calculation unit such as a CPU constituting the control unit 60, a storage unit such as a RAM or a nonvolatile memory, an input / output unit such as an IO port, a motor drive circuit, and the like. It is realized by.

  The detection signal generation unit 61 generates, for example, a rectangular wave state detection signal SG shown in FIG. 7 from a sine wave output signal output from the position detection device 31 and a threshold value set for the output signal. Output. In this embodiment, the state detection signal SG when the photosensor 57 detects the detection units 56a to 56c is at a high level, and the state detection signal SG when the photosensor 57 does not detect the detection units 56a to 56c is Become low level. That is, when the detection plate 56 rotates once together with the first cam 45a and the second cam 47a, the level of the state detection signal SG changes three times between the high level and the low level as shown in FIG.

  In the following, the configuration of the present embodiment will be described by taking as an example the state when the planetary gear 50 and the first driven gear 42 are engaged, but when the planetary gear 50 and the driven gear 19 are engaged, The state of the front retard roller 25 is detected based on the state detection signal SG. That is, based on the state detection signal SG, the target stop state of the front retard roller 25 is determined based on the state detection signal SG in the same manner as the target stop state of the rear sheet feeding unit 32 is detected as described later. Detected.

  In this embodiment, the high levels H1, H2, and H3 shown in FIG. 7 are signal levels of the state detection signal SG when the photosensor 57 detects the detection units 56a, 56b, and 56c, respectively. Further, in this embodiment, when the rear paper feed unit 32 is in the state shown in FIG. 5A, the state detection signal SG becomes the high level H1, and the rear paper feed unit 32 is in the state shown in FIG. At some time, the state detection signal SG is at the high level H2, and when the rear paper feed unit 32 is in the state shown in FIG. 5C, the state detection signal SG is at the high level H3. Note that the rectangular wave state detection signal SG may be output directly from the position detection device 31. In addition, when the photosensor 57 detects the detection units 56a to 56c, the state detection signal SG becomes a low level, and when the photosensor 57 does not detect the detection units 56a to 56c, the state detection signal SG is You may comprise so that it may become a high level.

  Here, in the normal operation, the rear sheet feeding unit 32 of the present embodiment stops in a state where the photosensor 57 detects any of the detection units 56a to 56c. Further, in the normal operation, the rear sheet feeding unit 32 operates until the photo sensor 57 detects the next detection units 56a to 56c adjacent in the rotation direction to the detection units 56a to 56c detected in the stopped state. That is, in the normal operation, the sub motor 38 stops in a state where the photosensor 57 detects any of the detection units 56a to 56c, and is adjacent to the detection units 56a to 56c detected in the stopped state in the rotation direction. The next detection units 56a to 56c are driven until the photo sensor 57 detects them.

  For example, the rear paper feed unit 32 stops when the state detection signal SG is at the high level H1, and operates from this stop state until the state detection signal SG becomes the high level H2. That is, in the normal operation, for example, the position corresponding to the high level H1 is the starting point of the operation of the rear sheet feeding unit 32, and the position corresponding to the high level H2 is the end point of the operation of the rear sheet feeding unit 32 (that is, the target stop position). ) In other words, the state corresponding to the high level H1 is the stopped state of the rear sheet feeding unit 32, and the state corresponding to the high level H2 is the target stopped state of the rear sheet feeding unit 32.

  The state detection unit 62 detects the target stop state of the rear sheet feeding unit 32 based on the state detection signal SG input from the detection signal generation unit 61. Specifically, the state detection unit 62 detects that the state detection signal SG input from the detection signal generation unit 61 has changed to a high level H2 corresponding to the target stop state of the rear sheet feeding unit 32, for example. . Then, the state detection unit 62 outputs a target stop state detection signal to the sub motor driving unit 63.

  The sub motor drive unit 63 starts the sub motor 38 in response to a control command from the control command unit 65, and when the detection signal of the target stop state is input from the state detection unit 62 (that is, the state detection signal SG is sent to the rear paper feed unit 32). When the state detecting unit 62 detects that the level has changed to the high levels H1 to H3 corresponding to the target stop state, the sub motor 38 is decelerated and stopped. In the present embodiment, the sub motor drive unit 63 drives the sub motor 38 so as to increase the drive torque of the sub motor 38 continuously and stepwise from the predetermined set minimum torque T1 to the predetermined set maximum torque T15. When the detection signal of the target stop state is input from the state detector 62, the sub motor 38 is decelerated with a predetermined deceleration torque T21, and then the sub motor 38 is stopped with a predetermined stop torque T31. In the present embodiment, the set minimum torque T1 is a predetermined first set torque, and the set maximum torque T15 is a predetermined second set torque.

  Specifically, first, a control table of the sub motor 38 as shown in FIG. That is, in the present embodiment, the storage unit 64 stores 15 set torques T1 to T15 that gradually increase from the set minimum torque T1 to the set maximum torque T15 as the drive torque of the sub motor 38, and the set torques T1 to T15. The driving times t1 to t15 of the sub motor 38 are set. The storage unit 64 is set with the deceleration torque T21 of the sub motor 38 and the driving time t21 of the sub motor 38 at the deceleration torque T21, and the driving time of the sub motor 38 at the stopping torque T31 and the stopping torque T31 of the sub motor 38. t31 is set.

  Then, after the sub motor 38 is activated by the control command from the control command unit 65, the sub motor drive unit 63 sets the set torque from the control table shown in FIG. 8 until the detection signal of the target stop state is input from the state detection unit 62. T1 to T15 and driving times t1 to t15 are sequentially read out, and the driving torque of the sub motor 38 is continuously increased sequentially. That is, first, even if the sub motor 38 is driven at the set minimum torque T1 for the driving time t1, if the target stop state detection signal is not input, the sub motor driving unit 63 sets the sub motor 38 at the set torque T2 for the driving time t2. Drive. Further, if the target stop state detection signal is not inputted even if the sub motor 38 is driven at the set torque T2 for the drive time t2, the sub motor drive unit 63 drives the sub motor 38 at the set torque T3 for the drive time t3. As described above, the sub motor driving unit 63 sequentially increases the driving torque of the sub motor 38. When the detection signal of the target stop state is input from the state detection unit 62, the sub motor driving unit 63 decelerates the sub motor 38 with a predetermined deceleration torque T21, and then stops the sub motor 38 with a predetermined stop torque T31. . In this embodiment, the sum total of the drive times t1 to t15 is, for example, 1.3 seconds.

  Since the sub motor 38 of this embodiment is PWM-controlled as described above, the set torques T1 to T15, the deceleration torque T21, and the stop torque T31 are changed from the on state where voltage is applied to the sub motor 38 to the next on state. It is set by the duty ratio which is the ratio of the ON time to the switching cycle which is the time interval until the state of. If the load applied to the sub motor 38 is constant, the rotation speed of the sub motor 38 increases as the drive torque increases.

  In this embodiment, as shown in FIG. 8, the first drive mode is configured by five set torques of set torques T1 to T5, and the second drive mode is set by five set torques of set torques T6 to T10. The third drive mode is configured by five set torques of set torques T11 to T15. The first drive mode is a drive mode in which the rear paper feed unit 32 can be driven to a target stop state during normal use in which the number of print sheets P set on the paper feed hopper 26 is a predetermined number or less. In the second drive mode, even when the number of print sheets P set on the paper feed hopper 26 is larger than the predetermined number and the load on the rear paper feed unit 32 is heavy, the rear paper feed unit 32 is brought to the target stop state. This is a drive mode that can be driven. In the third drive mode, even when the variation of the sub motor 38, the variation of the rear sheet feeding unit 32, etc. is maximized and the rear sheet feeding unit 32 is most difficult to drive, the rear sheet feeding unit This is a drive mode capable of driving 32 to the target stop state.

  Here, even if the sub motor driving unit 63 of this embodiment is driven at the set maximum torque T15, the rear sheet feeding unit 32 cannot be driven properly, and the state detection unit 62 causes the target stop of the rear sheet feeding unit 32 to stop. When the state cannot be detected, the sub motor 38 is driven again with a driving torque smaller than the set maximum torque T15. Specifically, even if the sub motor drive unit 63 is driven at the set maximum torque T15 and the state detection unit 62 cannot detect the target stop state of the rear paper feed unit 32, the sub motor 38 is operated until the target stop state is detected. The sub motor 38 is driven so as to increase the driving torque again from the set minimum torque T1 to the set maximum torque T15. That is, when the target stop state of the rear paper feed unit 32 cannot be detected by the state detection unit 62 even when driven at the set maximum torque T15, the sub motor driving unit 63 stores the target stop state in the storage unit 64 until the target stop state is detected. The set torques T1 to T15 are sequentially read again from the control table, and the sub motor 38 is driven. In addition, even if the sub motor driving unit 63 is driven at the set maximum torque T15, if the target stop state cannot be detected by the state detecting unit 62, the sub motor 38 is not stopped and the driving torque of the sub motor 38 is set to the set minimum torque T1. Then, the sub motor 38 is driven.

  In this embodiment, the sub motor drive unit 63 sets the drive torque of the sub motor 38 only when such a situation occurs for the first time while the first cam 45a and the second cam 47a rotate sequentially and finally make one rotation. The sub motor 38 is driven so as to increase again from the minimum torque T1 to the set maximum torque T15. That is, the sub motor drive unit 63 increases the drive torque of the sub motor 38 from the set minimum torque T1 to the set maximum torque T15 only once during the first cam 45a and the second cam 47a rotate once. The sub motor 38 is driven.

  For example, even when driven at the set maximum torque T15, the rear sheet feeding unit 32 is not driven from the state shown in FIG. 5A to the state shown in FIG. 5B, and the state detection signal SG changes from the high level H1 to the high level. Even if the sub motor 38 is driven such that the driving torque of the sub motor 38 is increased again from the set minimum torque T1 to the set maximum torque T15 in a situation where the level does not change to the level H2, the state detection signal SG is changed from the high level H1 to the high level H2. If the printer 1 does not change, the printer 1 performs error processing. Further, even when driven at the set maximum torque T15, the rear paper feeding section 32 is not driven from the state shown in FIG. 5A to the state shown in FIG. 5B, and the state detection signal SG changes from the high level H1 to the high level. In a situation where the level does not change to level H2, the sub motor 38 is driven so that the driving torque of the sub motor 38 is increased again from the set minimum torque T1 to the set maximum torque T15, and the state detection signal SG changes from the high level H1 to the high level H2. In this case, the rear sheet feeding unit 32 is not driven from the state shown in FIG. 5B to the state shown in FIG. 5C even if it is driven at the set maximum torque T15, and the state detection signal SG Even when the printer 1 does not change from the high level H2 to the high level H3, the printer 1 performs error processing.

(Outline control of sub motor)
FIG. 9 is a flowchart showing a schematic control flow of the sub motor 38 shown in FIG. Hereinafter, an outline of control of the sub motor 38 that drives the rear paper feeding unit 32 will be described.

  When a drive command for the rear paper feed unit 32 is input from the control command unit 65 to the control unit 60, the sub motor drive unit 63 drives the sub motor 38 to drive the rear paper feed unit 32. Specifically, the sub motor drive unit 63 first drives the sub motor 38 with the set minimum torque T1 in response to a command from the control command unit 65 (step S1). Then, while driving the sub motor 38, the state detection unit 62 determines whether or not the rear sheet feeding unit 32 is in the target stop state (step S2). That is, the state detection unit 62 determines whether or not the state detection signal SG input from the detection signal generation unit 61 has been changed to a high level H2 corresponding to the target stop state of the rear sheet feeding unit 32, for example.

  When the rear paper feed unit 32 is in the target stop state, a detection signal of the target stop state is input from the state detection unit 62 to the sub motor drive unit 63, and the sub motor drive unit 63 decelerates and stops the sub motor 38. (Step S3), the control sequence ends. On the other hand, if the rear paper feed unit 32 is not in the target stop state, it is determined whether or not the drive time t1 at the set minimum torque T1 has elapsed (step S4). If the drive time t1 has not elapsed, the process returns to step S1, and the drive of the sub motor 38 is continued. If the drive time t1 has elapsed, the sub motor drive unit 63 increases the drive torque (step S5) and drives the sub motor 38 (step S6). That is, the sub motor drive unit 63 drives the sub motor 38 by increasing the drive torque to the set torque T2.

  Then, while driving the sub motor 38, the state detection unit 62 determines whether or not the rear sheet feeding unit 32 is in the target stop state (step S7). When the rear paper feed unit 32 is in the target stop state, the process proceeds to step S3. When the rear paper feed unit 32 is not in the target stop state, the drive time t2 with the set torque T2 for driving the sub motor 38 is set. It is determined whether or not it has elapsed (step S8). If the drive time t2 has not elapsed, the process returns to step S6 and the drive of the sub motor 38 is continued. On the other hand, if the drive time t2 has elapsed, it is determined whether or not the drive torque of the sub motor 38 is the set maximum torque T15 (step S9).

  If the drive torque of the sub motor 38 is not the set maximum torque T15 in step S9, the process returns to step S5, and the sub motor drive unit 63 further increases the drive torque (step S5) to drive the sub motor 38 (step S6). . On the other hand, if the drive torque of the sub motor 38 is the set maximum torque T15 in step S9, the drive torque of the sub motor 38 becomes the set maximum torque T15 for the first time during one rotation of the first cam 45a and the second cam 47a. It is determined whether or not (step S10).

  In step S10, when the driving torque of the sub motor 38 reaches the set maximum torque T15 for the first time during one rotation of the first cam 45a and the second cam 47a, the process returns to step S1, and the sub motor driving unit 63 causes the sub motor 38 to The sub motor 38 is driven so as to increase the driving torque again from the set minimum torque T1 to the set maximum torque T15. On the other hand, if it is the second time that the drive torque of the sub motor 38 has reached the set maximum torque T15 during one rotation of the first cam 45a and the second cam 47a in step S10, predetermined error processing is performed. (Step S11), the control sequence ends.

  In the present embodiment, the drive torque of the sub motor 38 is set from the set minimum torque T1 until the target stop state of the rear sheet feeder 32 is detected by the first steps S1, S2, S4 to S9 that have not passed through step S10. A drive step for driving the sub motor 38 is configured so as to increase to the set maximum torque T15. In addition, when the target stop state of the rear sheet feeding unit 32 cannot be detected even when driven at the set maximum torque T15 by the second steps S1, S2, and S4 to S9 after step S10, it is more than the set maximum torque T15. A re-driving step for driving the sub motor 38 again with a small driving torque T1 to T14 is configured.

(Main effects of this form)
As described above, in this embodiment, the printer 1 includes the planetary gear unit 40 having the sun gear 49 and the planetary gear 50. Therefore, the two driven parts of the front retard roller 25 and the rear paper feed part 32 can be driven by one sub motor 38. Therefore, in this embodiment, the configuration of the printer 1 can be simplified.

  Further, in this embodiment, the sub motor drive unit 63 changes the drive torque of the sub motor 38 from the set minimum torque T1 to the set maximum torque until the state detection unit 62 detects the target stop state of the rear paper feed unit 32 and the front retard roller 25. The sub motor 38 is driven so as to gradually increase up to T15. Therefore, as in the present embodiment, after the state detection unit 62 detects that the state detection signal SG has changed to a high level H2 corresponding to the target stop state of the rear paper feed unit 32, the sub motor drive unit 63 Even if the sub motor 38 is configured to decelerate and stop, it is possible to drive the sub motor 38 with the minimum driving torque that can drive the rear paper feed unit 32, and therefore, the sub motor 38 is prevented from being overaccelerated. Thus, it is possible to ensure the stopping accuracy of the rear paper feeding unit 32. Similarly, it is possible to ensure the stopping accuracy of the front retard roller 25.

  Furthermore, in this embodiment, the clutch means 54 is configured between the sun gear 49 and the holding member 51. For this reason, even if an overload occurs on the sub motor 38, the sun gear 49, the planetary gear 50, or the like due to an unexpected load on the rear paper feed unit 32 side, the sub motor 38 or the sun gear 49 Or damage to the planetary gear 50 or the like can be prevented.

  Here, depending on the stop state of the first driven gear 42 and the driven gear 19 when not engaged with the planetary gear 50, the first driven gear 42 and the planetary gear 42 are engaged when the first driven gear 42 and the planetary gear 50 are engaged. 50 may not properly mesh with each other, or when the driven gear 19 and the planetary gear 50 are meshed, the driven gear 19 and the planetary gear 50 may not mesh properly. For this reason, slip occurs in the clutch means 54 between the sun gear 49 and the holding member 51, and the power transmission of the sub motor 38 to the holding member 51 is stopped. In this embodiment, even if the sub motor drive unit 63 is driven at the set maximum torque T15, and the state detection unit 62 cannot detect the target stop state of the rear paper feed unit 32 or the like, the sub motor is driven with a drive torque smaller than the set maximum torque T15. 38 is driven again. Accordingly, since the sub motor 38 is driven so as to sequentially increase the drive torque of the sub motor 38 from the set minimum torque T1 to the set maximum torque T15, once slipping occurs in the clutch means 54, thereafter, the holding member Even when the power transmission of the sub motor 38 to 51 is stopped, the slip of the clutch means 54 is stopped by reducing the driving torque of the sub motor 38, and the power transmission of the sub motor 38 to the holding member 51 is stopped. Can be resumed. As a result, the planetary gear 50 and the first driven gear 42 can be reliably engaged with each other, and the power of the sub motor 38 can be appropriately transmitted to the rear paper feeding unit 32. Further, the planetary gear 50 and the driven gear 19 can be reliably engaged with each other, and the power of the sub motor 38 can be appropriately transmitted to the front retard roller 25.

  Even when driven at the set maximum torque T15, the paper return lever 29 can return the print paper P to the paper feed hopper 26 depending on the state of the print paper P placed on the paper feed hopper 26, the type of the print paper P, and the like. There may be situations where this is not the case. In this embodiment, since the sub motor 38 can be driven again up to the set maximum torque T15, even in such a case, the print paper P is moved little by little with the paper return lever 29, and finally, The paper return lever 29 can also return the print paper P to the paper feed hopper 26. Alternatively, if the print paper P moves even a little, the print paper P may return to the paper feed hopper 26 as it is, and therefore the print paper P may be finally returned to the paper feed hopper 26 by the paper return lever 29. It becomes possible.

  In this embodiment, even if the sub motor drive unit 63 cannot drive the target stop state of the rear paper feed unit 32 or the like even when driven with the set maximum torque T15, the sub motor drive unit 63 increases the drive torque of the sub motor 38 until the target stop state is detected. The sub motor 38 is driven so as to increase again from the set minimum torque T1 to the set maximum torque T15. Therefore, the driving torque of the sub motor 38 can be temporarily reduced to the set minimum torque T1. Therefore, the slippage of the clutch means 54 can be stopped more effectively, and the power transmission of the sub motor 38 to the holding member 51 can be restarted.

  In this embodiment, even if the sub motor driving unit 63 is driven at the set maximum torque T15 and the target stop state of the rear paper feeding unit 32 or the like cannot be detected, the sub motor 38 does not stop the sub motor 38 and the driving torque of the sub motor 38 is increased. The torque is reduced to the set minimum torque T1. Therefore, it becomes possible to drive the rear paper feed section 32 or the front retard roller 25 for supplying the printing paper P more quickly, thereby improving the throughput.

(Other embodiments)
In the above-described embodiment, when the target stop state of the rear sheet feeding unit 32 or the like cannot be detected by the state detection unit 62 even when driven with the set maximum torque T15, the drive torque of the sub motor 38 is temporarily reduced to the set minimum torque T1. ing. In addition to this, for example, when the target stop state of the rear paper feeding unit 32 or the like cannot be detected even when driven by the set maximum torque T15, the drive torque of the sub motor 38 is set larger than the set minimum torque T1. The sub motor 38 may be driven again by lowering to either T14.

  In the embodiment described above, the sub motor drive unit 63 drives the sub motor 38 so as to increase the drive torque of the sub motor 38 continuously and stepwise from the set minimum torque T1 to the set maximum torque T15. In addition to this, for example, the sub motor drive unit 63 sequentially increases the drive torque of the sub motor 38 from the set torque T2 and the set torque T3 other than the set minimum torque T1 to the set torque T13 and the set torque T14 other than the set maximum torque T15. You may drive the submotor 38 so that it may raise. In this case, for example, the set torque T2 and the set torque T3 become a predetermined first set torque, and the set torque T13 and the set torque T14 become a predetermined second set torque.

  In the above-described form, when the target stop state of the rear paper feed unit 32 or the like cannot be detected by the state detection unit 62 even when driven with the set maximum torque T15, the drive torque of the sub motor 38 is not stopped without stopping the sub motor 38. The torque is reduced to the set minimum torque T1. In addition to this, for example, when the target detecting state cannot be detected by the state detection unit 62 even if the driving is performed with the set maximum torque T15, the sub motor 38 is temporarily stopped, and then the driving torque of the sub motor 38 is set to the set minimum torque. It may be lowered to T1.

  In the embodiment described above, the sub motor drive unit 63 does not drive the drive torque of the sub motor 38 only when the drive torque of the sub motor 38 reaches the set maximum torque T15 for the first time while the first cam 45a and the second cam 47a rotate once. Is driven to increase again from the set minimum torque T1 to the set maximum torque T15. However, the sub motor 38 is driven twice or more during one rotation of the first cam 45a and the second cam 47a. Even when the torque reaches the set maximum torque T15, the sub motor 38 may be driven such that the drive torque of the sub motor 38 is increased again from the set minimum torque T1 to the set maximum torque T15.

  In the embodiment described above, the position detection device 31 for detecting the state of the rear paper feed unit 32 and the like is configured by the detection plate 56 on which the detection units 56 a to 56 c are formed and the photo sensor 57. In addition to this, for example, a rotary encoder composed of a disc-shaped member having a plurality of slits or marks adjacent in the circumferential direction and a photosensor for detecting the slits or marks is provided on the rear surface side. You may use as a detection apparatus for detecting the state of the paper part 32 grade | etc.,.

  In the embodiment described above, the driven unit is the rear paper feeding unit 32 or the front retard roller 25. In addition to this, for example, the configuration of the present embodiment can be applied to a driven portion to which the power of the motor is transmitted by a mechanism similar to that of the planetary gear portion 40. Further, the configuration of the present embodiment can be applied to various devices such as a laser printer having a mechanism similar to that of the planetary gear unit 40 in addition to the ink jet printer.

1 is a side view showing a schematic configuration of a main part of a printer according to an embodiment of the present invention. FIG. 2 is a diagram schematically illustrating a schematic configuration of a drive mechanism and a control unit of a rear sheet feeding unit in FIG. 1. The fragmentary sectional view which shows the planetary gear part of FIG. The figure which shows the planetary gear part from the EE direction of FIG. The figure for demonstrating operation | movement of the rear paper feed part of FIG. The side view which shows the position detection apparatus of FIG. The figure which shows the waveform of the state detection signal produced | generated based on the output signal from the position detection apparatus of FIG. The table | surface which shows the control table of the submotor memorize | stored in the memory | storage part of FIG. The flowchart which shows the general | schematic control flow of the submotor of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Printer, 19 Driven gear, 25 Front retard roller (driven part), 26 Paper feed hopper (medium supply hopper), 28 Rear retard roller (double feed prevention roller), 29 Paper return lever (medium return lever), 31 position Detection device (detection device), 32 Rear paper feed unit (driven portion, print medium supply unit), 38 Sub motor (motor), 39 Drive gear, 41 Drive gear, 49 Sun gear, 50 Planetary gear, 51 Holding member, 54 Clutch means, 60 control unit, 62 state detection unit, 63 sub motor drive unit (motor drive unit), P printing paper (print medium), S1, S2, S4 to S9 drive step, S1, S2, S4 to S9 redrive step , T1 set minimum torque (first set torque), T15 set maximum torque (second set torque).

Claims (6)

A driven part that is driven to print on a print medium, a motor that drives the driven part, a drive gear that is connected to the motor, a driven gear that is connected to the driven part, and the drive A sun gear meshing with the gear; a planetary gear meshing with the sun gear and meshing with the driven gear; A holding member that can rotate in the occlusal direction of the driven gear and the planetary gear around the rotation center, and a clutch means that uses frictional force and can stop the power transmission of the motor to the holding member; A detection device disposed on the driven part side of the planetary gear in the direction of power transmission from the motor to the driven part for detecting the state of the driven part; and controlling the motor And a control unit,
The control unit includes a state detection unit that detects a target stop state of the driven unit based on an output signal from the detection device, and a driving torque of the motor until the state detection unit detects the target stop state. When the motor is driven so as to increase from a predetermined first set torque to a predetermined second set torque, and the state detection unit cannot detect the target stop state even when driven by the second set torque And a motor driving unit that drives the motor again with a driving torque smaller than the second set torque.   The printer according to claim 1, wherein the first set torque is a set minimum torque of the drive torque, and the second set torque is a set maximum torque of the drive torque.   When the motor drive unit cannot detect the target stop state even when driven at the set maximum torque, the motor drive unit changes the drive torque of the motor from the set minimum torque to the set maximum torque until the target stop state is detected. 3. The printer according to claim 2, wherein the motor is driven so as to be raised again.   The motor drive unit reduces the drive torque of the motor to the set minimum torque without stopping the motor when the target stop state cannot be detected even when driven at the set maximum torque. The printer according to claim 3.   The driven part prevents a medium supply hopper on which the print medium before printing is placed, and a multi-feed of the print medium conveyed from the medium supply hopper toward a print area on which the print medium is printed. 5. A print medium supply unit comprising: a multi-feed prevention roller for performing the operation and a medium return lever for returning the print medium of a specified number of print sheets or more to the medium supply hopper. Printer. A driven part that is driven to print on a print medium, a motor that drives the driven part, a drive gear that is connected to the motor, a driven gear that is connected to the driven part, and the drive A sun gear meshing with the gear; a planetary gear meshing with the sun gear and meshing with the driven gear; A holding member that can rotate in the occlusal direction of the driven gear and the planetary gear around the rotation center, and a clutch means that uses frictional force and can stop the power transmission of the motor to the holding member; A printer is provided that includes a detection device that is disposed closer to the driven unit than the planetary gear in the direction of power transmission from the motor to the driven unit and detects the state of the driven unit. A method of controlling a printer that,
The motor is configured to increase the drive torque of the motor from a predetermined first set torque to a predetermined second set torque until a target stop state of the driven portion is detected based on an output signal from the detection device. And when the target stop state cannot be detected based on the output signal from the detection device even when driven with the second set torque, the motor is driven with a drive torque smaller than the second set torque. And a re-driving step of driving the printer again.

Images