JP2006248070A - Gap adjustment mechanism, printer equipped with this gap adjustment mechanism, and gap adjustment method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gap adjustment mechanism which can carry out adjustment of a platen gap in a short time, and to provide a printer equipped with this gap adjustment mechanism, and a gap adjustment method. <P>SOLUTION: The printer 10 is equipped with height position adjusting means 73 and 74 which adjust a height position of a printing head 32 by driving force at a motor 71, a motor controlling means 86 which controls motor driving information, and detecting means 75 and 77 which detect whether or not the motor 71 is started to move by controlled driving of the motor 71 at the motor controlling means 86. The motor controlling means 86 tries to start moving the motor 71 by adjusting the motor driving information stepwise. At the same time, when the starting of movement is detected by the detecting means 75 and 77, the motor driving information of a final stage is stored in a storage means 83. The motor driving information is read out from the storage means 83 in next driving of the motor 71, whereby the motor 71 is driven by the motor driving information. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a gap adjusting mechanism, a printer including the gap adjusting mechanism, and a gap adjusting method.

  In recent years, the number of printers that can print on various types of printing objects is increasing in inkjet printers. Among such printing objects, there are recording media such as dedicated glossy paper, photographic paper, CD-R, etc. in addition to plain paper, and the thickness dimension varies depending on the type of printing object. And recent printers are required to ensure print quality for all of various print objects.

  In order to satisfy the above-described requirements, in recent printers, a distance (a platen gap; hereinafter, abbreviated as PG) between a print head that ejects ink droplets and a print object has an appropriate dimension. In addition, there is a model equipped with a mechanism (auto platen gap mechanism; hereinafter, abbreviated as an APG mechanism) that automatically adjusts. Note that details of the APG mechanism are disclosed in, for example, Patent Document 1. In Patent Document 1, the height of a carriage provided coaxially with the gap adjustment cam is switched by the rotation of the gap adjustment cam. Further, by providing a plurality of light shielding plates on the outer periphery of the disk and detecting the presence or absence of the light shielding plates with a detection sensor, the PG according to the thickness of the printing object can be adjusted.

Japanese Unexamined Patent Publication No. 2004-314591 (see paragraph numbers 0026, 0036, 0037, etc.)

  By the way, in the above-described APG mechanism, a DC motor is currently used, and a method of adjusting a duty ratio in PWM control is adopted instead of current control. Here, if the duty ratio applied to the DC motor is too high, the average voltage becomes too high, and as a result, a more excessive torque is generated from the DC motor. In that case, in each gear train that transmits the driving force from the gap adjusting cam and the DC motor described above, meshing noise, sliding, etc. occur more than necessary, and the user feels noisy.

  Therefore, the present applicant has filed an application of Japanese Patent Application No. 2003 and proposes to suppress the speed increase in the DC motor of the APG mechanism and to suppress the generation of noise from the drive part of the APG mechanism as much as possible. However, in the application of Japanese Patent Application No. 2003-2003, after applying a low torque T1 in all the flags, if no flag is detected within a predetermined time, a higher torque T2 is applied and a torque T2 is further applied. If no flag is detected within a predetermined time, the highest torque T3 is applied. For this reason, when the gap adjusting cam or the like cannot start with the torques T1 and T2, there is a problem that it takes time to achieve an appropriate PG adjustment due to the existence of a waiting time for each torque.

  Such a problem becomes conspicuous as the number of flags increases. That is, when the flag at one end of the rotation range of the gap adjustment cam reaches the flag at the other end of the rotation range, a plurality of flags are passed, but each time the flag passes, a predetermined waiting time is passed. If time exists, it takes a long time to adjust to an appropriate PG.

  The present invention has been made on the basis of the above circumstances, and an object of the present invention is to provide a gap adjusting mechanism capable of adjusting the platen gap in a short time, a printer including the gap adjusting mechanism, and a gap adjusting method. It is intended to provide.

  In order to solve the above-described problems, the present invention provides a motor and a motor in a gap adjustment mechanism that adjusts a distance between a print head that discharges ink to a print object and a paper feed surface on which the print object is fed. Height position adjusting means for adjusting the height position of the print head with respect to the paper feed surface by the driving force generated by the motor, motor control means for transmitting motor drive information based on a control command to the motor, and motor control means Detecting means for detecting whether or not the motor has started to be driven by the motor control drive at the motor, and the motor control means adjusts the motor drive information given to the motor in a stepwise manner. If the detection means detects that the motor has started to move, the final stage motor drive information required for the movement start is recorded in the storage means. Is allowed, the driving of the next motor, reads the final stage of the motor drive information required to start moving the motor stored in the storage means, by the read motor driving information is for driving the motor.

  When configured in this way, the motor control means tries to start the motor by stepwise adjusting the motor drive information transmitted toward the motor. When the motor begins to move due to this attempt to move, the height position of the print head relative to the paper feed surface is adjusted by the height position adjusting means. Further, the movement of the motor is detected by the detecting means. When the movement start is detected by the detection means, the final stage motor drive information required for the movement start is stored in the storage means. Based on the information stored in the storage means, in the next motor drive, the motor drive information at the final stage is read from the storage means, and the motor is driven by the motor drive information.

  In this way, when the motor is driven next time, it is possible to drive the motor based on the final stage motor drive information required for the previous movement start stored in the storage means. Therefore, in the next drive of the motor, it is not possible to sequentially apply the motor drive information from the first stage so that the motor does not start at all. Therefore, when the motor is driven next time, motor drive information necessary for starting movement can be given from the beginning, and the time until movement can be shortened.

  In another invention, in addition to the above-described invention, the motor is controlled and driven by PWM control, and the motor drive information is duty ratio information related to the duty ratio in this PWM control.

  When configured in this way, the motor can easily and accurately perform stepwise voltage control applied to the motor by PWM control that adjusts the duty ratio of the pulse voltage. In addition, by performing PWM control, it is possible to increase the power efficiency.

  Furthermore, in addition to the above-described invention, in another aspect of the invention, the motor control means performs control for increasing the duty ratio required for starting the motor step by step, and the motor control means has a duty ratio at the final stage. If the detection means does not detect that the print head has been adjusted to an appropriate height position due to the movement of the motor even when a voltage corresponding to is applied, it is determined that an error has occurred, and the height of the subsequent print head The position adjustment is terminated.

  When configured in this way, the duty ratio applied to the motor is increased stepwise, and detection is performed by the detection means, and when the motor starts moving, the duty ratio necessary for starting the motor is detected. It becomes possible. Of the duty ratios that are gradually increased, the final stage duty ratio is stored in the storage means. In addition, if the start of the motor cannot be detected by the detection means due to the duty ratio at the final stage, an external load is applied, for example, some object is stuck to the print head. Can be considered. Therefore, by determining that the error is described above, it is possible to prevent the motor from moving excessively, and to prevent damage to the print head or the like.

  In another invention, in addition to the above-described invention, the height position adjusting means is attached to a fixed pin provided with a fixed height position and a carriage shaft on which a carriage having a print head slides. And a cam surface whose radius changes along the circumferential direction, and the cam surface slides with respect to the fixed pin by rotation, whereby the height position of the carriage shaft and the print head with respect to the fixed pin is determined. And an adjustable PG cam.

  In this case, the height position of the carriage shaft relative to the fixed pin can be changed by sliding the cam surface of the PG cam relative to the fixed pin. That is, when the PG cam rotates, the cam surface of the PG cam slides, and the height position of the carriage shaft with respect to the fixed pin can be changed. Therefore, the height positions of the carriage and the print head that move along the carriage axis can be changed, and the gap between the print head and the paper feed surface can be adjusted satisfactorily.

  Furthermore, in addition to the above-described invention, the PG cam further includes a plurality of stable regions in which the radius of the cam surface does not change even if the PG cam moves along the circumferential direction, and adjacent stable regions. And a transition region in which the radius of the cam surface changes when moved along the circumferential direction.

  In such a configuration, even if the fixing pin is pressed against the stable region, the radius of the stable region does not change along the circumferential direction, so the PG cam does not rotate, and the height of the carriage shaft The position can be stably held, and the gap between the print head and the paper feed surface can be maintained constant. Further, when the fixing pin is pressed against the transition region, the radius of the transition region changes along the circumferential direction. Therefore, when the PG cam rotates in a state where the fixing pin is pressed against this transition region, the height position of the carriage shaft can be changed, and the gap adjustment can be performed satisfactorily.

  According to another invention, in addition to the above-mentioned invention, the detection means further includes a light emitting portion and a light receiving portion that receives the light generated by the light emitting portion and faces the light emitting portion. Has a flag detection sensor that becomes the detection area, and a plurality of protruding parts that protrude outward from the reference part, correspond to the stable area and block the passage of light, and each protruding part can pass through the detection area And a flag plate disposed on the surface.

  In such a configuration, when the protruding portion of the flag plate is located in the detection region, the light emitted from the light emitting unit is blocked and the light receiving unit cannot receive the light. Accordingly, it is possible to detect the protruding portion, and it is possible to detect the position of the stable region corresponding to the protruding portion. That is, when the stable region is in a state where the fixing pin is pressed, the position of the stable region can be detected using the light emitting unit and the light receiving unit if the protruding portion reaches the detection region. .

  Furthermore, in another invention, in addition to the above-described invention, the Duty ratio information is stored in the storage means every time the protruding portion is detected by the detecting means. Each duty ratio information is read out, and the motor is driven based on the read duty ratio information.

  When configured in this way, the duty ratio information of the duty ratio required for the motor to start moving can be stored in the storage means each time the protruding portion is detected. Therefore, when the motor is driven next time at each projecting part, the voltage of the duty ratio necessary for starting movement can be immediately applied to the motor, and the time between starting movements can be shortened. It becomes.

  In another invention, in addition to the above-described invention, the motor control means controls to reduce the duty ratio given to the motor when the protruding portion is detected by the flag detection sensor, and the height of the print head. When it is determined that the position is appropriate, it further outputs duty ratio information for stopping the motor to the motor, and when it is determined that the height position of the print head is not appropriate, the motor is again output. Control is performed to adjust the Duty ratio step by step depending on whether or not can start moving.

  In such a configuration, when the protruding portion is detected by the flag detection sensor, the duty ratio of the voltage applied to the motor is reduced by the motor control means. This prevents a high duty ratio voltage from being applied to the motor after detection. Here, when the protruding portion is detected, the load generated in the motor is usually low in a certain region after the detection. Therefore, as described above, when the duty ratio of the voltage is reduced, it is possible to prevent a high duty ratio from being applied to the motor with a light load. As a result, the motor can be driven faster and mechanical noise can be prevented from increasing. In addition, when it is determined that the height position of the print head is appropriate, a voltage with a duty ratio for stopping the motor is applied to the motor, so that the motor can be stopped at the appropriate position. When the height position of the print head is not appropriate, the motor starts to move again, and the duty ratio is adjusted stepwise. Therefore, while adjusting the duty ratio of the voltage applied to the motor step by step, the drive can be continued until a protruding portion corresponding to an appropriate position is detected. It is possible to adjust the height position to an appropriate height position.

  Furthermore, in another invention, in addition to each of the above-described inventions, the motor control means may further determine whether or not the motor has started moving until a certain waiting time elapses based on detection by the detection means. If the motor does not start before the predetermined time elapses, control is performed to increase the duty ratio given to the motor by one step.

  In such a configuration, it is determined whether or not the motor has started to move during a certain waiting time based on detection by the detection means. When no movement is started, the duty ratio given to the motor is increased by one step. By repeating this determination of movement, it is possible to move the motor with the minimum duty ratio voltage and to reduce the noise generated from the mechanical part of the print head height position adjustment. Become.

  In another invention, in addition to the above-described inventions, motor drive information stored in the storage means is deleted when the power is turned off. In such a configuration, even when the duty ratio is temporarily maximized, it is possible to return to the normal duty ratio when the power is turned on next time. In other words, the startup load is often temporarily increased due to ink solidification, dust adhesion, and the like in the printer. In that case, the duty ratio adjusted in stages stored in the storage means remains at the maximum, and thereafter, all the motors are driven with the voltage of the maximum duty ratio, from the aspect of achieving quietness. Then, it is not preferable. Thus, if the motor drive information stored in the storage means is deleted when the printer is turned off, such a problem can be prevented from occurring.

  Furthermore, in another invention, each invention of the gap adjusting mechanism described above is applied to a printer. In such a configuration, when the motor is driven next time, it is possible to drive the motor based on the last-stage motor drive information necessary for starting the previous movement stored in the storage unit. Therefore, in the next drive of the motor, it is not possible to sequentially apply the motor drive information from the first stage so that the motor does not start at all. Therefore, when the motor is driven next time, motor drive information necessary for starting movement can be given from the beginning, and the time until movement can be shortened.

  In another aspect of the invention, a driving force generated by a motor is applied to the height position adjusting unit, so that a print head that discharges ink to a print target and a paper feed surface on which the print target is fed are provided. In the gap adjustment method for adjusting the interval, the motor drive information that is output to the motor is adjusted step by step, so that the motor starts to move by the drive information adjustment step that tries to start the motor and the drive information adjustment step. A detection step for detecting whether or not the motor has been moved, a storage step for storing in the storage means the motor drive information at the final stage required for the movement start in the detection step, and the next time In the driving of the motor, the reading process for reading out the motor driving information at the final stage required to start the movement of the motor stored in the storage means, and the reading process A re-driving step of driving the motor by the motor driving information read Te are those having a.

  In the case of such a configuration, in the drive information adjustment step, motor movement is tried by adjusting the motor drive information in stages. In this case, the movement of the motor is detected in the detection process. Further, in the storage step, when it is detected in the detection step that the motor has started to move, the final stage motor drive information required for the start of movement is stored in the storage means. Further, in the reading process, the motor driving information required for the previous driving of the motor is read from the storage means at the next driving of the motor. In the re-drive process, the motor is driven based on the read motor drive information.

  In this way, when the motor is driven next time, it is possible to drive the motor based on the final stage motor drive information required for the previous movement start stored in the storage means. Therefore, in the next drive of the motor, it is not possible to sequentially apply the motor drive information from the first stage so that the motor does not start at all. Therefore, when the motor is driven next time, motor drive information necessary for starting movement can be given from the beginning, and the time until movement can be shortened.

  Hereinafter, an embodiment of a gap adjusting mechanism of the present invention, a printer using the gap adjusting mechanism, and a gap adjusting method will be described with reference to FIGS. Note that the printer 10 of the present embodiment is an ink jet printer, but the ink jet printer may be an apparatus that employs any ejection method as long as the apparatus is capable of printing by ejecting ink.

  In the following description, the lower side refers to the installation surface 1 side where the printer 10 is installed, and the upper side refers to the side away from the installation surface 1. A direction in which a carriage 30 described later moves is a main scanning direction, and a direction perpendicular to the main scanning direction and a direction in which the print target 12 is conveyed is a sub-scanning direction. Further, the side on which the printing object 12 is supplied will be described as a paper feeding side (rear end side), and the side on which the printing object 12 is discharged will be described as a paper discharge side (front side).

  The printer 10 includes a chassis 11 that contacts the installation surface 1, and various units are mounted on the chassis 11. The various units include a carriage mechanism 20 that reciprocates the carriage 30 in the main scanning direction by a carriage motor (CR motor 25), and a paper conveyance mechanism that conveys the print object 12 by a PF motor 45 (corresponding to a motor and a paper feed motor). 40, an auto platen gap adjusting mechanism (APG mechanism) 70 for adjusting a distance between a platen 56 and a print head 32, which will be described later, and the like, and a control unit 80 shown in FIGS.

  Here, the carriage mechanism 20 will be described. As shown in FIGS. 1 and 2, the carriage mechanism 20 includes a carriage 30. The carriage mechanism 20 is disposed on the back side of a support frame 21, a carriage shaft 24 that is supported by the support frame 21, and slidably holds the carriage 30, and a shielding plate portion 22 described later. Carriage motor (CR motor 25), a gear pulley 26 attached to the CR motor 25, an endless belt 27, and a driven pulley 28 that stretches the endless belt 27 between the gear pulley 26. , A code plate 36 and a linear encoder 37 are provided.

  As shown in FIG. 1, the support frame 21 includes a shielding plate portion 22 and side plate portions 23 that are bent toward the paper discharge side at both ends of the shielding plate portion 22. A pair of side plate portions 23 support a carriage shaft 24 that guides the slide of the carriage 30 along the length of the chassis 11. The carriage shaft 24 is inserted into a long hole 23 a provided in the side plate portion 23. A CR motor 25 for driving the gear pulley 26 is provided on the back side of the shielding plate portion 22. In the present embodiment, the CR motor 25 is a DC motor, similar to a PG motor described later.

  Here, the long hole 23a of the side part plate part 23 is provided so that the longitudinal direction may go up and down. In addition, the width of the long hole 23 a in the short direction has only a dimension necessary for insertion of the carriage shaft 24. For this reason, when a PG cam 73 described later is rotated, the carriage shaft 24 slides along the longitudinal direction inside the long hole 23a.

  As shown in FIG. 3 and the like, a carriage 30 is provided to face the platen 56. As shown in FIG. 2 and the like, the carriage 30 stores K (black), LM (light magenta), LC (light cyan), cyan (C), magenta (M), and yellow (Y) inks, respectively. For example, six cartridges 31 are detachably mounted. The cartridges 31 to be mounted are not limited to six colors, and may have any number of colors such as four colors, seven colors, and eight colors. The ink filled in the cartridge 31 is not limited to dye-based ink, and other types of ink such as pigment-based ink may be mounted.

  As shown in FIG. 3 and the like, a print head 32 is provided below the carriage 30. In the print head 32, nozzles (not shown) are arranged in a line in the transport direction of the printing object 12 to form nozzle lines corresponding to the respective color inks. In this embodiment, the nozzle row is composed of, for example, 180 nozzles, of which the 180th nozzle is located on the paper feed side and the first nozzle is located on the paper discharge side.

  In addition, for each nozzle in the nozzle row, a piezoelectric element (not shown) that is one of the electrostrictive elements and has excellent responsiveness is arranged. The piezo element is installed at a position in contact with the wall surface that forms the ink passage, and the wall surface is pushed by the operation of the piezo element, and ink droplets can be ejected from the nozzles at the end of the ink passage. It has become.

  The print head 32 is not limited to the piezo driving method using a piezo element, and other methods may be used. Other methods include, for example, a heater method in which ink is heated with a heater and the generated foam force is used, a magnetostriction method in which a magnetostrictive element is used, an electrostatic method in which electrostatic force is used, and a mist method in which mist is controlled by an electric field. Etc. are mentioned as main methods.

  As shown in FIG. 2 and the like, the carriage mechanism 20 includes a code plate 36 and a linear encoder 37. The code plate 36 is formed with slits at predetermined intervals. A linear encoder 37 is attached to the back side of the carriage 30 facing the code plate 36. The code plate 36 and the linear encoder 37 can detect the current position of the carriage 30.

  Details of the paper transport mechanism 40 will be described with reference to FIG. The paper transport mechanism 40 shown in FIG. 3 includes a paper feed roller 41, a hopper 42, and a separation pad 43.

  The paper feed roller 41 that is rotationally driven by the PF motor 45 shown in FIGS. 1 and 2 has a roller body 41a and a rubber material 41b wound around the outer periphery of the roller body 41a. The side view of the paper feed roller 41 is substantially D-shaped. Of the paper supply roller 41, a relatively thin sheet of the print object 12 is fed by the arc portion of the rubber material 41b. At the same time, the sheet is allowed to pass through the flat portion of the rubber material 41b so that no conveyance load is applied during the conveyance operation by the discharge roller pair 60.

  The hopper 42 is a plate-like member on which a sheet can be placed, and is provided in an inclined posture shown in FIG. The hopper 42 can be swung by a cam mechanism (not shown) around an upper rotation shaft 42a. By such swinging, the lower end portion of the hopper 42 is elastically pressed against or separated from the paper feed roller 41. Accordingly, when the hopper 42 swings in the press-contact direction with respect to the paper feed roller 41, the bundle of sheets accumulated on the hopper 42 comes into pressure contact with the paper feed roller 41. When the paper feed roller 41 rotates in this pressure contact state, the uppermost sheet is fed to the paper discharge side.

  The separation pad 43 is made of a member having a high friction coefficient, and is provided at a position facing the paper feed roller 41. When the paper feed roller 41 rotates, the arc portion of the rubber material 41b and the separation pad 43 are pressed against each other. The uppermost sheet sent by the rotation of the paper feed roller 41 passes through this pressure contact portion and proceeds to the paper discharge side. Subsequent sheets are prevented from proceeding to the paper discharge side due to the presence of such pressure contact portions. Thereby, double feeding of paper is prevented.

  Note that the paper transport mechanism 40 may employ a system having a retard roller in addition to the system having the separation pad 43. When the retard roller is provided, the print object 12 can be fed in without turning the front end of the print object 12 due to rotation / stop between the paper feed roller 41 and the retard roller.

  Further, a paper guide 44 made of a plate-like body is provided substantially horizontally on the paper discharge side with respect to the hopper 42. The leading edge of the paper fed by the paper feed roller 41 is in contact with the paper guide 44 obliquely and is smoothly guided to the paper discharge side. Further, a PF roller pair 50 including a PF drive roller 51 and a PF driven roller 52 is provided on the paper discharge side with respect to the paper guide 44. Here, the PF driven roller 52 always receives a biasing force toward the PF drive roller 51 by the action of a biasing force (elastic force) of a spring 54 described later.

  For this reason, the print object 12 conveyed through the hopper 42 side or through an opening 57 described later is between the PF drive roller 51 and the PF driven roller 52 with respect to the print object 12. It is pinched while giving a biasing force. Further, the PF driving roller 51 is rotated by the driving force transmitted from the PF motor 45 shown in FIGS. 1 and 2. Therefore, when the PF motor 45 is operated for one step at a constant pitch, the print object 12 sandwiched between the PF roller pair 50 is conveyed to the paper discharge side for the one step.

  The PF driven roller 52 is pivotally supported on the paper discharge side of the driven roller holder 53. The driven roller holder 53 is provided so as to be rotatable about a rotation shaft 53a. Further, the driven roller holder 53 is urged to rotate in a direction (counterclockwise in FIG. 3) in which the PF driven roller 52 is always in pressure contact with the PF drive roller 51 by a spring 54 as an elastic member. The spring 54 is a torsion coil spring, and is inserted through the rotation shaft 53a.

  On the other hand, the surface of the PF driven roller 52 that is in contact with the PF drive roller 51 is made of a member having a lower friction than that of the above-described grip body 51b. It is provided so as to cover the surface.

  Further, a paper detector for detecting the passage of the printing object 12 in the vicinity of the driven roller holder 53 located on the 0 digit side (the front side of the paper surface in FIG. 3; the reverse side in FIG. 3 is the 80 digit side). 55 is provided. The paper detector 55 includes a sensor body 55b and a detection lever 55a. Among these, the detection lever 55a has a substantially "<" shape on the side surface, and is rotatable about a rotation shaft 55c near the center. The sensor body 55b is located above the detection lever 55a, and includes a light emitting part (not shown) and a light receiving part (not shown) that receives light from the light emitting part. The upper side from the rotation shaft 55c is configured to block and pass light from the light emitting unit to the light receiving unit by a rotation operation.

  Therefore, as shown in FIG. 3, when the detection lever 55a is rotated so as to be pushed upward as the print target 12 passes, the upper side of the detection lever 55a is detached from the sensor main body 55b. As a result, the light receiving unit is in a light receiving state, and the passage of the front end of the printing object 12 is detected. Further, when the rear end of the printing object 12 passes the detection lever 55a, the detection lever 55a rotates in a direction to return downward. Thereby, the light receiving unit is switched to the non-light receiving state, and the passage of the rear end of the print object 12 is detected.

  Further, on the paper discharge side of the PF drive roller 51, the platen 56 and the above-described print head 32 are disposed so as to face each other in the vertical direction. The platen 56 supports the printing object 12 conveyed below the print head 32 by the discharge roller pair 60 from below.

  Further, a paper discharge roller pair 60 similar to the above-described PF roller pair 50 is provided on the paper discharge side of the platen 56. The paper discharge roller pair 60 includes a paper discharge driving roller 61 and a paper discharge driven roller 62. The discharge driving roller 61 is rotated by the driving force transmitted from the PF motor 45. Further, a biasing force is applied to the paper discharge driven roller 62 by the spring 63 in a direction in which the paper discharge driven roller 62 is always pressed against the paper discharge driving roller 61.

  The print object 12 is sandwiched between the paper discharge roller pair 60 while being given a predetermined urging force. In this state, when the paper discharge driving roller 61 rotates, the paper is discharged leftward in FIG. The paper discharge drive roller 61 employs a configuration in which rubber rollers are intermittently arranged in the width direction on a shaft body extending in the width direction of the print target 12. The PF motor 45 described above adopts a configuration in which the driving force is distributed to the PF driving roller 51 and the paper discharge driving roller 61. However, a configuration may be employed in which a separate motor is provided in addition to the PF motor 45 and the discharge driving roller 61 is driven by the motor.

  An opening 57 is provided below the hopper 42 described above. The opening 57 is an opening on the rear end side of the printer 10 and has a width in the main scanning direction sufficient to allow the print target 12 to pass therethrough. An example of the printing object 12 that passes through the opening 57 is a CD-R that is placed on a tray.

  Next, details of the auto platen gap mechanism (APG mechanism) 70 will be described with reference to FIGS. As shown in FIG. 4 and others, the APG mechanism 70 is a mechanism for adjusting the height position of the carriage shaft 24. The APG mechanism 70 includes a carriage shaft 24, a PG motor 71, an APG gear train 72 that transmits a driving force from the PG motor 71, a PG cam 73, and a fixing pin 74 against which the PG cam 73 is pressed, A flag plate 75 for detecting the rotational position of the PG cam 73, a flag detection sensor 77, and a control unit 80 are provided.

  Among these, the PG motor 71 is a motor for providing a driving force for adjusting the platen gap (PG), and is a DC motor in the present embodiment. The PG motor 71 is a DC motor capable of PWM control, and adjusts the average voltage applied to the DC motor by adjusting the width (Duty ratio) of the pulse voltage to control the driving of the DC motor. It is possible. In this PWM control, there are a method using a uniform pulse with a uniform pulse width and a method using a non-uniform pulse with a variable pulse width. Any pulse signal may be used. Further, any pulse signal may be used by various combinations of adjusting the duty ratio of the voltage pulse and the period of the voltage pulse. Similarly, the CR motor 25 and the PF motor 45 are also DC motors capable of PWM control.

  As shown in FIGS. 5 and 6, the APG gear train 72 includes a plurality of gears, and drives the PG motor 71 at a reduced speed to transmit the PG cam 73 in order to rotate the PG cam 73. It is a transmission means. Of the APG gear train 72, the final output gear 72 a is fixedly attached to the carriage shaft 24. A PG cam 73 is also fixedly attached to the carriage shaft 24.

  Further, as shown in FIG. 7, the PG cam 73 is a cam member provided so that the radius with respect to the rotation center varies stepwise. The PG cams 73 are provided as many as the number of platen gaps (PG) that can be set. In the present embodiment, five PG cams 73 are provided, and the five radii are provided so as to change stepwise. As shown in FIGS. 4 and 5, the outer peripheral cam surface 73 a of the PG cam 73 is pressed against the fixing pin 74. The fixing pin 74 is fixedly provided on the side plate portion 23. For this reason, when the PG cam 73 is rotated, the height position of the carriage shaft 24 can be changed by the contact of the cam surface 73a with the fixing pin 74. The PG cam 73 and the fixing pin 74 constitute a height position adjusting unit.

  Here, as shown in FIG. 7, a stable region S and a transition region T exist on the cam surface 73 a of the PG cam 73. The stable region S is a region that maintains a constant radius within a predetermined angle range, and the transition region T has a radius that increases or decreases from the center of the PG cam 73 to the cam surface 73a as it rotates. It is an area. In the present embodiment, five stable regions S are provided, and the radius values are r1 to r5 in order from the smallest to the largest. In the following description, when each of the stable regions S is referred to, the stable regions S1 to S5 are denoted by reference numerals in order from the smallest radius. Similarly, when the transition regions T are referred to, the transition regions T1 to T4 are denoted by reference numerals in order from the smallest radius.

  The number of stable regions S is not limited to five, and may be any number as long as it is two or more. Further, the cam surface 73a may be configured such that a stable region S having a maximum radius exists in the middle portion of the cam surface 73a, in addition to gradually increasing or decreasing the radius as the radius proceeds in the circumferential direction. Moreover, it is good also as an arrangement | positioning which adjoins irrespective of a radius so that the switching of the radius between the types of printing objects 12 with a high use frequency can be performed quickly.

  Further, as shown in FIG. 6, the flag plate 75 constitutes a part of the detection means, and is provided so as to be coaxial with the gear 72 b in the middle of the APG gear train 72 and rotate simultaneously. The flag plate 75 is configured by providing a plurality of flags 76 (corresponding to projecting portions) in the projecting direction on the outer peripheral side of the disk-shaped portion 75a (corresponding to the reference portion). The flag 76 is a light shielding portion that does not transmit light, and can block light when passing through a detection region P of a flag detection sensor 77 described later.

  As shown in FIG. 8, in the present embodiment, the flag plate 75 is provided with a total of six flags 76. Among these flags 76, five flags 761 to 765 (hereinafter, when referring to each of the five flags 76, the flags 761 to 765 are assigned in order from the one corresponding to the stable region S1. ) Corresponds to the five stages of the PG cam 73. Further, in the present embodiment, the flag 76 for the release mechanism (not shown) of the paper guide 44 described above (hereinafter, when the flag 76 corresponding to the release is referred to, a flag 766 and a reference numeral are attached). 1) is provided.

  Further, the flag detection sensor 77 is disposed on the flag plate 75 in a close proximity. The flag detection sensor 77 constitutes a part of detection means, and is an optical sensor having a light emitting portion 77a and a light receiving portion 77b. All the flags 761 to 766 are detected between the light emitting portion 77a and the light receiving portion 77b. It is provided so as to be able to pass through the region P. As shown in FIG. 9, in the present embodiment, when any of the flags 76 is present in the detection region P, the flag detection sensor 77 transmits an H level signal and the flag 76 is detected in the detection region P. If not, an L level signal is transmitted.

  Here, the positional relationship between the flag plate 77 and the PG cam 73 will be described. When the flag 76 reaches the detection area P of the flag detection sensor 77, one of the stable areas S of the cam surface 73a comes into pressure contact with the fixed pin 74. In addition, the flag 761 corresponds to the stable region S1 having the radius r1, the flag 762 corresponds to the stable region S2 having the radius r2, and the flag 763 corresponds to the stable region S3 having the radius r3. The flag 764 corresponds to the stable region S4 having the radius r4, and the flag 765 corresponds to the stable region S5 having the radius r5. The flag 766 is a position for opening the paper guide 44, and corresponds to an open position of a paper guide cam (not shown). As described above, when the flag detection sensor 77 transmits the H signal, any one of the stable regions S of the cam surface 73a comes into pressure contact with the fixed pin 74.

  Here, among the five stable regions S1 to S5, the stable region S1 has a small distance between the fixing pin 74 and the carriage shaft 24, and the carriage shaft 24 is positioned at the lowest position. Can be set. For this reason, the stable region S1 corresponds to a thin paper PG. Hereinafter, based on the same idea, the stable region S2 corresponds to a normal thickness paper (plain paper or the like), and the stable region S3 corresponds to a slightly thick special paper or the like. The stable region S4 corresponds to thicker paper such as photoboard paper or predetermined photographic paper. Further, the stable region S5 corresponds to a thickest region such as a CD-R printing tray.

  In the present embodiment, it is preferable that the edge of the flag 77 is detected and the H signal is transmitted while the stable region S is already reached. In this way, when the stop operation of the PG motor 71 described later is performed according to the detection of the flag 77, the PG can be held more reliably. However, you may comprise so that the edge of the flag 77 and the edge of the stable area | region S may correspond.

  Next, the configuration of the control unit 80 will be described with reference to FIG. The control unit 80 includes a bus 80a, a CPU 81, a ROM 82, a RAM 83, a character generator (CG) 84, an ASIC 85, a DC unit 86, a PG motor driver 87, a PF motor driver 88, a CR motor driver 89, a head driver 90, and a nonvolatile memory 91. Etc.

  Further, the CPU 81 and the DC unit 86 include the above-described paper detector 55, a PW sensor (not shown) for detecting the paper width, a rotary encoder 92 (to be described later), a linear encoder (not shown) for detecting the movement amount of the carriage 30, and the printer 10. Each output signal of the power source SW for turning on / off the power source is input.

  The CPU 81 performs arithmetic processing for executing the control program for the printer 10 stored in the ROM 82, the nonvolatile memory 91, and the like, and other necessary arithmetic processing.

  The ROM 82 stores a control program for controlling the printer 10 and data necessary for processing. In the present embodiment, the ROM 82 stores waveform information and the like of the drive control program corresponding to the type of the printing object 12. The ASIC 85 has a built-in parallel interface circuit, and can receive a print signal supplied from the computer 100 via the interface 101.

  The RAM 83 is a memory that temporarily stores a program being executed by the CPU 81 or data being calculated. The nonvolatile memory 91 is a memory for storing various data that needs to be retained even after the inkjet printer 10 is turned off. Note that the RAM 83 corresponds to a storage unit and stores duty ratio information related to the duty ratio.

  Unlike the above-described linear encoder 37, the rotary encoder 92 is provided with a code plate in a disc shape. However, the other configuration is the same as that of the linear encoder 37.

  The DC unit 86 corresponds to the motor control means and is a control circuit for performing speed control of the CR motor 25, the PF motor 45, the PG motor 71, and the like, which are DC motors. The DC unit 86 is a control signal for controlling the speed of the PG motor 71 based on a control command sent from the CPU 81 (a timing signal for turning on / off the switching element of the PG motor driver 87, and the motor (Corresponding to drive information) is transmitted to the PG motor driver 87.

  The DC unit 86 is a drive control portion for performing predetermined control. According to the DC unit 86, the motors such as the CR motor 25 and the PF motor 45 can also be controlled based on, for example, the control in the PID control unit and the acceleration control unit. The portion related to the control of the PG motor 71 will be described with reference to FIG.

  As shown in FIG. 11, the DC unit 86 includes a counter 86a, an output control unit 86b, a PWM signal generation unit 86c, and a timer 86d. Among these, the counter 86a counts the number of H signals transmitted from the flag detection sensor 77, and outputs a count signal obtained by the counting to the output control unit 86b. Further, a control command from the CPU 81, a count signal from the counter 86a, and a timer signal from the timer 86d are input to the output control unit 86b. Here, the control command in this case is information regarding the count number stored in the RAM 83. Then, the count signal from the counter 86a is compared with the control command (count number) from the CPU 81, and when the target count number is reached, a control signal corresponding to deceleration is output to the PWM signal generation unit 86c. After that, a signal corresponding to the stop is output after a predetermined time has elapsed.

  Further, the PWM signal generation unit 86c outputs a predetermined PWM signal to the PG motor driver 87 based on the control signal from the output control unit 86b. Here, the control signal output from the output controller 86b to the PG motor driver 87 is a timing signal for turning on / off a switching element (not shown) existing in the PG motor driver 86b. A constant voltage is separately input to the PG motor driver 86b. Then, the PG motor driver 87 outputs a sawtooth analog current in which the on / off of the voltage is controlled, toward the PG motor 71.

  The timer 86d outputs a timer signal toward the output control unit 86b. Then, when the specified output wait time is reached in the output control unit 86b, the output control unit 86b increases the duty ratio stepwise or sends a control signal for stopping driving to the PWM signal generation unit 86c. Output.

  Each component in the above-described control unit 80 is connected by a bus 80a that is a signal line. By such a bus 80a, the CPU 81, ROM 82, RAM 83, CG 84, ASIC 85, nonvolatile memory 91, and the like are connected to each other, and data can be exchanged between them.

  The printer 10 includes an interface 101. A computer 100 is connected via the interface 101.

  Details of the control when operating the APG mechanism 70 of the printer 10 using the above-described configuration will be described below based on the control flow of FIG. 12 and the torque diagrams of FIGS. 13 and 14.

  When the type of the printing object 12 is switched while the printer 10 is turned on, the CPU 81 issues a control command for starting the PG motor 71 to the DC unit 86, and the control command is output control. When input to the unit 86b, the control signal corresponding to the control command is transmitted to the PWM signal generation unit 86c. Then, the PWM signal generator 86 c causes a current corresponding to the duty ratio of the torque T 1 to flow through the PG motor 71 via the PG motor driver 87. Thereby, the PG motor 71 starts to be started (step S10).

  Here, in the first stage, the output control unit 86b transmits a control signal corresponding to the torque T1 to the PWM signal generation unit 86c. Next, it is determined whether or not the detection signal (H signal) of the flag 76 has been received from the flag detection sensor 77 (step S11; part of the detection process). This determination is also a determination as to whether or not the PG motor 71 has started to move. In this determination, when it is determined that the detection signal has not been received (in the case of No), it is then determined whether or not a predetermined time has elapsed based on the reception of the timer signal from the timer 86d (step S12). ).

  If it is determined in step S12 that the predetermined time has elapsed (in the case of Yes), the flag 76 (the edge of the flag 76) is not detected even if the predetermined waiting time has elapsed. Accordingly, in this case, it is determined that the flag plate 75 cannot move (the PG motor 71 cannot move) at the torque T1. Therefore, the output control unit 86b sends a control signal corresponding to the torque T2 larger than the torque T1 (control signal for increasing the torque by one step to T3; corresponding to the duty ratio information) to the PWM signal generation unit 86c. (Step S13; part of the drive information adjustment step). In step S12, when it is determined that the predetermined time has not elapsed (in the case of No), the process returns to step S11.

  After the transmission of S13 described above, it is determined whether or not to receive a detection signal from the flag detection sensor 77 similar to Step S11 described above (Step S14; a part of the detection process), and no detection signal is received in Step S14. Is determined (in the case of No), it is determined whether or not a predetermined time has elapsed (step S15).

  Further, when it is determined in step S15 that the predetermined time has elapsed (in the case of Yes), the flag 76 (the edge of the flag 76) is not detected even if the predetermined waiting time has elapsed. Therefore, in this case, it is determined that the flag plate 75 cannot move at the torque T2. Therefore, the output control unit 86b transmits a control signal (control signal for further increasing the torque by one step to T3) corresponding to the torque T3 larger than the torque T2 to the PWM signal generating unit 86c (step). S16: Part of the drive information adjustment step). Here, the torque T3 is the largest torque, and is set to a magnitude that allows the flag plate 75 to be reliably rotated. When it is determined in step S15 described above that the predetermined time has not elapsed (in the case of No), the process returns to step S14.

  After the transmission in step S16 described above, it is determined whether or not to receive a detection signal from the flag detection sensor 77 similar to that in steps S11 and S14 described above (step S17; part of the detection process), and the detection signal is received in step S17. When it is determined that it has not been performed (in the case of No), it is determined whether or not a predetermined time has elapsed (step S18).

  If it is determined in step S18 that the predetermined time has elapsed (in the case of Yes), it means that even a large torque such as torque T3 cannot start moving. In that case, it is processed that some error has occurred in the APG mechanism 70 (step S19), and the activation of the PG motor 71 is terminated. If it is determined in step S18 that the predetermined time has not elapsed (in the case of No), the process returns to step S17.

  If it is determined in steps S11, S14, and S17 that the flag 76 is detected (Yes), the duty ratio information corresponding to the torques T1 to T3 at that time is stored in the RAM 83 (step S20; storage). Corresponding to the process). Next, the output control unit 76b transmits a control signal corresponding to the torque T4 having a value smaller than the torque T1 to the PWM signal generation unit 86c, and drives the PG motor 71 at a duty ratio corresponding to the torque T4. (Step S21). Here, the torque T4 is a torque smaller than the torque T1. Here, the duty ratio corresponding to the torque T4 is a duty ratio for preventing the speed of the PG motor 71 from being increased more than necessary when the flag 76 presses the fixing pin 74. That is, when the flag 76 is pressed against the fixed pin 74, the stable region S is pressed against the fixed pin 74. At this time, the carriage shaft 24 is not lifted. Therefore, the load on the PG motor 71 is reduced. Therefore, in order to prevent the speed of the PG motor 71 from increasing, a voltage having a duty ratio smaller than the above-described torque T1 and corresponding to the torque T4 is applied to the PG motor 71 (FIGS. 13 and 14). reference).

  After the torque T4 has elapsed, the output control unit 86b compares the count number in the given control command with the count number counted by the counter 86a, and determines whether or not a predetermined count number has been reached (step). S22). When it is determined that the predetermined count has been reached, the output control unit 86b sends a control signal corresponding to the torque T5 (= brake output) for stopping the PG motor 71 to the PWM signal generation unit 86c. The transmission is performed (step S23). Thereby, the PG motor 71 stops completely.

  Note that the stop position in this case is not a stop in the vicinity of the edge of the flag 76 but a stop at a substantially central portion away from the edge of the flag 76 by passing through step S21. If it is determined in step S22 that the predetermined count has not been reached, output control / counting for the next flag 76 is continued.

  As described above, the duty ratio information corresponding to any of the torques T1 to T3 capable of rotating the PG cam 73 in each transition region T is stored in the RAM 83. Accordingly, when the APG mechanism 70 is driven again thereafter, the duty ratio information corresponding to the torques T1 to T3 when the PG motor 71 starts moving is read out (corresponding to the reading process) and stored in the RAM 83. If the torque control of the PG motor 71 is performed based on the above, the PG cam 73 can be immediately rotated, and a useless time required for the determination can be omitted. That is, in step S10, the duty ratio information related to the start of movement of the PG motor 71 stored in the RAM 83 may be read out and reflected in the driving of the PG motor 71 (in this case, step S10 corresponds to the re-driving step). To do).

  This is shown in FIG. FIG. 13A shows an image when the flag plate 75 starts to move with the torque T 3 and is stopped when the first flag 76 is detected by the flag detection sensor 77. In FIG. 13B, the flag plate 75 starts to move with the torque T3, the first flag 76 is detected, and then the flag plate 75 starts to move again with the torque T3, and the second flag 76 is detected. It is an image when stopping after that. Further, FIG. 14A shows an image of stopping when the flag plate 75 starts to move with the torque T 2 and the first flag 76 is detected by the flag detection sensor 77. Further, in FIG. 13B, the flag plate 75 starts to move with the torque T2, the first flag 76 is detected, and then the flag plate 75 starts to move again with the torque T3, and the second flag 76 is detected. It is an image when stopping after that.

  In the torque diagrams shown in FIGS. 13 and 14, the time interval τ1 corresponding to the output of the torque T1, the time interval τ2 corresponding to the torque T2, and the time interval τ3 corresponding to the torque T3 are also shown. Slightly changing the Duty ratio. Accordingly, the torque diagram draws a convex curve in each of the time intervals τ1 to τ3.

  Here, the storage of the duty ratio information in the RAM 83 is used as long as the power is turned on. That is, in many cases, the startup load of the printer 10 temporarily increases due to ink solidification, dust adhesion, or the like. In that case, the duty ratio information corresponding to the torque T3 is stored in the RAM 83, and once it falls into the state activated by the torque T3, the subsequent activation is performed unless the duty ratio information corresponding to the torque T3 is deleted. All start from torque T3, which is not preferable. Therefore, the storage of the duty ratio information in the RAM 83 is used as long as the power is turned on.

  However, such storage may be performed not on the RAM 83 but on the nonvolatile memory 91. In this case, the nonvolatile memory 91 corresponds to the storage unit. In addition, when the duty ratio information is stored in the nonvolatile memory 91, the duty ratio information stored once can be used even after the power is turned off. Therefore, a typical load for starting the PG motor 71 was measured. In case, it becomes effective.

  The duty ratio information is stored in the RAM 83 as described above whenever the flags 76 are detected as necessary. However, the duty ratio information corresponding to the movement of the PG motor 71 until the detection of the flags 76 is stored. Is preferably performed for each type of print object 12. That is, if the type of the printing object 12 is different, it is assumed that the required duty ratio differs when the PG motor 71 starts to move. Therefore, it is preferable that the duty ratio information corresponding to the type of the printing object 12 is stored in the RAM 83 in association with the detection of each flag 76.

  According to the APG mechanism 70 having such a configuration, the printer 10 using the APG mechanism 70, and the gap adjusting method, the PG motor 71 starts to move by adjusting the duty ratio stepwise and the PG motor 71 starts moving. In this case, the duty ratio information required for the start of the movement is stored in the RAM 83. Therefore, when the PG motor 71 is driven next time, the PG motor 71 can be driven based on the information of the last stage duty ratio stored in the RAM 83 and required for the previous movement.

  Therefore, when the PG motor 71 is driven next time, the PG motor 71 is not applied sequentially from a small duty ratio at the initial stage so that the PG motor 71 does not start moving at all. Therefore, when the PG motor 71 is driven next time, information on the duty ratio necessary and sufficient for the start of movement can be given from the beginning, and the time until the start of movement can be shortened. In particular, in the case where the flag 761 at one end of the PG cam 71 reaches the flag 765 at the other end, a plurality of flags 76 are passed through, so that the effect obtained is increased by the accumulation of time reduction until the movement starts. .

  Further, when the PG motor 71 is driven next time, a large duty ratio voltage is not applied unnecessarily. Therefore, it is possible to prevent the PG motor 71 from rotating too fast and generating large noise from the gear meshing portion, the sliding portion, and the like of the APG mechanism 70, and the printer 10 can be kept quiet.

  The PG motor 71 is controlled and driven by PWM control. For this reason, the PG motor 71 can output an appropriate torque by appropriately adjusting the duty ratio, and the control can be easily and accurately performed. In addition, by performing PWM control, it is possible to increase the power efficiency.

  Further, even when the duty ratio voltage corresponding to the torque T3 is applied, if the flag 76 is not detected by the flag detection sensor 77, it is determined that there is an error, and the subsequent PG adjustment is terminated. Here, as described above, the duty ratio corresponding to the torque T3 is set to a magnitude that allows the flag plate 75 to be reliably rotated. In this case, it is conceivable that an external load is acting on the print head 32, for example. Therefore, by determining that the error is described above, it is possible to prevent the PG motor 71 from starting excessively and to prevent the print head 32 and the like from being damaged.

  Further, in this embodiment, the height position of the carriage shaft 24 with respect to the fixed pin 74 is changed by the rotation of the PG cam 73 and the sliding of the cam surface 73 a with respect to the fixed pin 74. Therefore, the height position of the print head 32 that moves along the carriage shaft 24 can be reliably changed, and PG adjustment can be performed satisfactorily. Further, the PG cam 73 has a stable region S in which the radius to the cam surface 73a does not change and a transition region T in which the radius changes. Therefore, when the fixing pin 74 is pressed against the stable region S, the PG cam 73 does not rotate, and the height position of the carriage shaft 24 can be stably held, and the platen gap (PG) is kept constant. Can be maintained. Further, when the fixing pin 74 is pressed against the transition region T and the PG cam 73 rotates in this state, the height position of the carriage shaft 24 can be changed, and PG adjustment can be performed satisfactorily.

  The flag detection sensor 77 includes a light emitting unit 77 a and a light receiving unit 77 b, and the flag plate 75 includes a plurality of flags 76. For this reason, when the flag 76 is located in the detection region P, the light emitted from the light emitting unit 77a is blocked and cannot be received by the light receiving unit 77b. Thereby, the flag 76 can be detected, and the position of the stable region S corresponding to the flag 76 can be detected. In other words, when the predetermined flag 76 reaches the detection region P when the predetermined stable region S on the cam surface 73a is pressing the fixing pin 74, the position of the stable region S is detected by the light emitting unit. 77a and light receiving portion 77b can be used.

  Further, in the present embodiment, the RAM 83 stores duty ratio information related to the duty ratio in association with detection of the flag 76. Therefore, when the PG motor 71 is driven next time, the duty ratio voltage required until the detection of the predetermined flag 76 can be immediately applied to the PG motor 71, and the time until the movement starts. Can be shortened.

  When the flag 76 is detected by the flag detection sensor 77, the duty ratio of the voltage applied to the PG motor 71 is lowered to the duty ratio corresponding to the torque T4. Therefore, it is possible to prevent a voltage having a high duty ratio from being applied to the PG motor 71 after the flag 76 is detected. Here, when the flag 76 is detected, the load on the PG motor 71 is usually low in a state where the stable region S after the detection is pressed against the fixed pin 74. Therefore, as described above, when the duty ratio of the voltage is reduced so as to correspond to the torque T4, it is possible to prevent a high duty ratio from being applied to the PG motor 71 with a light load. As a result, the PG motor 71 can be driven faster and mechanical noise can be prevented from increasing.

  If it is determined that the height position of the print head 32 is appropriate, a voltage having a duty ratio corresponding to the torque T5 is applied to the PG motor 71. Therefore, the PG motor 71 can be stopped at an appropriate position. If the height position of the print head 32 is not appropriate, the PG motor 71 starts to move again, and the duty ratio is increased stepwise. Therefore, while increasing the duty ratio given to the PG motor 71 in stages, the driving can be continued until the flag 76 corresponding to the appropriate position is detected. It is possible to adjust the height position to an appropriate height position.

  Further, whether or not the flag 76 is detected during a certain waiting time is determined by detection by the flag detection sensor 77. If the flag 76 is not detected, it is given to the PG motor 71. Duty ratio is increased by one step. Therefore, the PG motor 71 can always be moved at a voltage with the minimum duty ratio, and noise generated from the mechanical part of the height position adjustment of the print head 32 can be reduced.

  Also, the duty ratio information stored in the RAM 83 and associated with the detection of each flag 76 is erased when the printer 10 is turned off. For this reason, even when the duty ratio is temporarily maximized, it is possible to return to the normal duty ratio when the printer 10 is turned on next time. That is, the startup load is often temporarily increased due to ink solidification, dust adhesion, and the like in the printer 10. In that case, when the duty ratio information stored in the RAM 83 remains corresponding to the torque T3 which is the maximum torque, the PG motor 71 is all driven at the voltage of the maximum duty ratio and becomes quiet. It is not preferable from the aspect of aiming. For this reason, when the duty ratio information is erased when the printer 10 is turned off, such a problem can be prevented.

  Although one embodiment of the present invention has been described above, the present invention can be variously modified. This will be described below.

  In the above-described embodiment, the motor is described as the PG motor 71. However, the motor is not limited to the PG motor 71, and other motors may be used. As another motor, for example, a PF motor 45 is cited. In this case, the present invention may be used particularly in a configuration in which the driving force of the PF motor 71 is distributed to the APG mechanism. In addition to the PF motor 45, for example, the same control may be performed for a pump motor for sucking ink.

  In the above-described embodiment, the case where the PG motor 71 is driven and controlled by PWM control has been described. However, drive control of the PG motor 71 is not necessarily limited to performing PWM control. For example, when a predetermined voltage value is applied without performing PWM control, the current value flowing through the PG motor 71 may be adjusted by appropriately adjusting the voltage value. The present invention can also be applied to the case where current control is performed on the PG motor 71 instead of voltage control.

  In the above-described embodiment, the case where the output from the PG motor 71 has three stages of torque T1 to torque T3 is described. However, the output from the PG motor 71 is not limited to three stages of torque T1 to torque T3, and may be four stages or more, or two stages.

  In the control in the above-described embodiment, it is preferable to prepare separate tables for the forward rotation direction and the reverse rotation direction of the PG motor 71, respectively. For example, when the carriage shaft 24 is lifted by the passage of the transition region T in the forward rotation direction of the PG motor 71 and the carriage shaft 24 is lowered by the passage of the transition region T in the reverse rotation direction, the PG motor 71 The given duty ratios corresponding to the torques T1 to T3 are naturally different values. For this reason, it is preferable to facilitate separate tables for the forward direction and the reverse direction of the PG motor 71, respectively.

  In the above-described embodiment, the PG cam 73 and the fixing pin 74 constitute the height position adjusting means, but the height position adjusting means is not limited to this. For example, a height position adjusting unit that adjusts the height position of the carriage shaft 24 or the like by a screw mechanism may be used, and other mechanisms may be used.

  Further, in the above-described embodiment, the detection means is constituted by the flag plate 75 and the flag detection sensor 77. However, the detection means is not limited to this. For example, in addition to using the flag plate 75, for example, slits penetrating the disk are formed in the circumferential direction at a predetermined pitch, and the arrival at the stable region S is detected by receiving / blocking light through the slits. You may do it. Further, a contact type sensor may be provided, and the arrival at the stable region S may be detected by contact of the sensor with the flag 76.

1 is a perspective view illustrating a configuration of a printer according to an embodiment of the present invention. FIG. 2 is a schematic diagram illustrating a configuration of a printer. FIG. 6 is a side sectional view of a portion related to paper feeding of the printer. It is a perspective view which shows a part of APG mechanism. It is a side view which shows a part of APG mechanism. It is a perspective view which shows arrangement | positioning of the gear wheel train, PG cam, and flag board of an APG mechanism. It is a top view which shows the shape of PG cam. It is a perspective view which shows the shape of a flag board, and arrangement | positioning of a flag detection sensor. It is a figure which shows the detection signal by a flag detection sensor. It is a block diagram of the control part which performs various control of a printer. It is a block diagram which shows schematic structure of DC unit. It is a flowchart which shows the mode of the torque control in a PG motor. It is a figure which shows an example of the torque change until the movement start / stop of PG motor. It is a figure which shows an example of the torque change until the movement start / stop of PG motor.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Printer, 12 ... Print object, 20 ... Carriage mechanism, 25 ... CR motor, 27 ... Belt, 30 ... Carriage, 31 ... Cartridge, 32 ... Print head, 40 ... Paper conveyance mechanism, 45 ... PF motor, 50 ... PF roller pair, 70 ... APG mechanism, 71 ... PG motor (corresponding to motor), 72 ... gear wheel train, 73 ... PG cam (corresponding to a part of height position adjusting means), 74 ... fixing pin (height position) 75 ... flag plate (corresponding to a part of the detecting means), 76 ... flag (corresponding to a protruding part), 77 ... flag detection sensor (corresponding to a part of the detecting means), 80 ... Control unit, 82 ... ROM, 83 ... RAM (corresponding to storage means), 86 ... DC unit (corresponding to motor control means), 89 ... head driver, 91 ... nonvolatile memory

Claims (12)

In a gap adjustment mechanism that adjusts the distance between a print head that discharges ink to a print object and a paper feed surface on which the print object is sent,
A motor,
A height position adjusting means for adjusting a height position of the print head with respect to the paper feed surface by a driving force generated by the motor;
Motor control means for transmitting motor drive information based on a control command toward the motor;
Detecting means for detecting whether or not the motor has started to be moved by the control driving of the motor by the motor control means;
Comprising
The motor control means is
By adjusting the motor drive information given to the motor in stages, the motor starts to move,
When it is detected by the detection means that the motor has started to move, the motor drive information at the final stage required for the movement start is stored in the storage means,
In the next drive of the motor, the motor drive information at the final stage required for starting the movement of the motor stored in the storage means is read, and the motor is driven by the read motor drive information.
A gap adjusting mechanism characterized by that.   The gap adjustment mechanism according to claim 1, wherein the motor is controlled and driven by PWM control, and the motor drive information is Duty ratio information related to the Duty ratio in the PWM control.   The motor control means performs control for increasing the Duty ratio required for starting the motor in a stepwise manner, and the motor control means also applies the voltage corresponding to the Duty ratio in the final stage. If the detection means does not detect that the print head has been adjusted to an appropriate height position due to the start of motor movement, it is determined that an error has occurred, and the subsequent adjustment of the height position of the print head is terminated. The gap adjusting mechanism according to claim 2. The height position adjusting means includes
A fixing pin having a fixed height position;
A carriage having the print head is attached to a carriage shaft that slides, and has a cam surface whose radius changes along the circumferential direction, and the cam surface slides with respect to the fixed pin by rotation. A PG cam capable of adjusting the height position of the carriage shaft and the print head with respect to the fixed pin;
The gap adjusting mechanism according to claim 2, further comprising: In the PG cam,
A plurality of stable regions that are regions in which the radius of the cam surface does not change even when moving along a circumferential direction;
A transition region that is located between the adjacent stable regions and changes in radius of the cam surface when moved along a circumferential direction; and
The gap adjusting mechanism according to claim 4, further comprising: The detection means includes
A flag detection sensor that includes a light-emitting unit and a light-receiving unit that receives the light generated by the light-emitting unit and faces the light-emitting unit;
A flag plate that protrudes outward from a reference portion, has a plurality of protruding portions that correspond to the stable region and blocks the passage of light, and each protruding portion is disposed so as to be able to pass through the detection region. When,
The gap adjusting mechanism according to claim 5, further comprising: The duty ratio information is stored in the storage unit every time the protruding portion is detected by the detection unit,
In the next drive of the motor, the duty ratio information for each protruding portion is read, and the motor is driven based on the read duty ratio information.
The gap adjusting mechanism according to claim 6. The motor control means includes
When the protruding portion is detected by the flag detection sensor, the duty ratio given to the motor is controlled to be reduced, and
When it is determined that the height position of the print head is appropriate, the duty ratio information for further stopping the motor is output to the motor,
When it is determined that the height position of the print head is not appropriate, depending on whether or not the motor was able to start again, control to adjust the Duty ratio stepwise is performed.
8. The gap adjusting mechanism according to claim 6 or 7, wherein: The motor control means includes
Based on detection by the detection means, whether or not the motor was able to start before a certain waiting time elapses,
If the motor does not start before the fixed time elapses, control is performed to increase the Duty ratio given to the motor by one step.
The gap adjusting mechanism according to any one of claims 1 to 8, wherein   The gap adjusting mechanism according to claim 1, wherein the motor drive information stored in the storage unit is erased when the power is turned off.   A printer comprising the gap adjusting mechanism according to claim 1. A gap adjusting method for adjusting a distance between a print head that discharges ink to a printing object and a paper feed surface to which the printing object is fed by applying a driving force generated by a motor to the height position adjusting means. In
A drive information adjustment step that attempts to start the movement of the motor by adjusting the motor drive information output to the motor stepwise,
A detection step of detecting whether or not the motor has started to move by the drive information adjustment step;
In the detection step, when it is detected that the motor has started to move, a storage step of storing in the storage means the motor drive information at the final stage required for the movement start;
In the next drive of the motor, a reading step of reading out the motor drive information at the final stage required for starting the movement of the motor stored in the storage means;
A re-driving step of driving the motor by the motor driving information read by the reading step;
A gap adjustment method comprising:

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