JP2015089635A - Printing device, and step-out detection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately detect step-out in a printing device that moves a carriage by driving of a stepping motor.SOLUTION: A printing device 1 comprises: a carriage movement motor 66 that is a stepping motor; a carriage that moves according to driving of the motor; a third rotary encoder 92 for detecting a travel amount of the carriage; and a control unit 50 for detecting step-out of the carriage movement motor 66 on the basis of a comparison between a travel amount of the carriage that is detected when the carriage movement motor 66 is driven by a predetermined amount and a predicted travel amount of the carriage 70 that is predicted when the carriage movement motor 66 is driven by the predetermined amount when not being a step-out state.

Description

  The present invention relates to a printing apparatus including a carriage that moves in accordance with driving of a stepping motor, and a stepping motor step-out detection method.

  2. Description of the Related Art Conventionally, there is known a printing apparatus that includes a print head and includes a carriage that can reciprocate in the main scanning direction (see, for example, Patent Document 1).

JP 2011-230515 A

In the printing apparatus including the carriage as described above, the carriage can be moved by driving the stepping motor. With such a configuration, the positioning control of the carriage can be executed precisely.
Here, in the case where the carriage is moved by the stepping motor, if the stepping motor steps out, the printing apparatus may be affected due to the stepping out.
The present invention has been made in view of the above-described circumstances, and an object thereof is to accurately detect a step-out in a printing apparatus that moves a carriage by driving a stepping motor.

In order to achieve the above object, the present invention provides a printing apparatus, which includes a stepping motor, a print head, a carriage that moves according to the driving of the stepping motor, and an encoder that detects the amount of movement of the carriage. And the amount of movement of the carriage detected by the encoder when the stepping motor is driven by a predetermined amount, and the carriage predicted when the stepping motor is driven by the predetermined amount without being stepped out. And a control unit for detecting step-out of the stepping motor based on comparison with the predicted movement amount.
Here, when the actual movement amount of the carriage when the stepping motor is driven by a predetermined amount is different from the predicted movement amount predicted when the stepping motor is not stepped out, the stepping motor has stepped out. there is a possibility. According to the above configuration, the printing apparatus detects the carriage movement detected by the encoder when the stepping motor is driven by a predetermined amount, and the carriage prediction that is predicted when the stepping motor is driven by the predetermined amount. A step-out of the stepping motor is detected based on the comparison with the movement amount. For this reason, it is possible to accurately detect the step-out of the stepping motor.

In the printing apparatus according to the aspect of the invention, the encoder may be a rotary encoder that detects a movement amount of the carriage by detecting a rotation amount of a rotating body that rotates according to driving of the stepping motor, and the control unit Is the rotation amount of the rotating body detected by the encoder when the stepping motor is driven by a predetermined amount, and the rotation predicted when the stepping motor is driven by the predetermined amount without being stepped out. A step-out of the stepping motor is detected based on a comparison with the predicted amount of rotation of the body.
According to this configuration, it is possible to accurately detect the step-out of the stepping motor by using the rotary encoder that detects the rotation amount of the rotating body that rotates according to the driving of the stepping motor.

Further, the printing apparatus of the present invention is configured such that when the stepping motor is driven by one step without being stepped out, the first rotation amount is detected as the rotation amount of the rotating body by the encoder. The controller is configured to detect the amount of rotation of the rotating body detected by the encoder when the stepping motor is driven by a predetermined number of steps, and the predetermined amount of time when the stepping motor is driven by the predetermined number of steps. A step-out of the stepping motor is detected based on a comparison with a predicted rotation amount of the rotating body predicted based on a relationship between the number of steps and the first rotation amount.
According to this configuration, when the stepping motor is driven by one step without being stepped out, the first rotation amount is detected as the rotation amount of the rotating body by the encoder. It is possible to accurately detect the step-out of the stepping motor based on a comparison between the actual rotation amount and the predicted rotation amount of the rotating body.

In the printing apparatus of the present invention, the rotating body is a driven gear connected via a power transmission mechanism to a drive gear provided on a motor shaft of the stepping motor, and the power transmission mechanism The driven gear is rotated by the first rotation amount in accordance with the driving of the stepping motor for one step when the stepping motor is not in operation.
According to this configuration, when the stepping motor is driven by one step without being stepped out, a configuration in which the first rotation amount is detected as the rotation amount of the rotating body by the encoder is used using the power transmission mechanism. Can be realized.

In the printing apparatus according to the aspect of the invention, the control unit may determine the number of k steps (where k> 1) the stepping motor is driven in the predetermined period as the cumulative rotation amount of the rotating body in the predetermined period by the encoder. And a step amount of the stepping motor is detected by determining whether a rotation amount obtained by the product of the first rotation amount and a rotation amount reflecting a margin in the calculated rotation amount is detected. It is characterized by that.
According to the configuration of the present invention, it is possible to accurately detect the step-out of the stepping motor based on a comparison between the accumulated rotation amount of the rotating body in a predetermined period and the rotation amount predicted in the predetermined period.

Further, in the printing apparatus of the present invention, each time the control unit drives the stepping motor by n (where n ≧ 1) steps, the encoder rotates the rotary body as the rotation amount of the first rotation amount. The stepping motor step-out is detected by determining whether a rotation amount obtained by the product of n or a rotation amount reflecting a margin in the obtained rotation amount is detected.
According to this configuration, since step-out is detected every time the stepping motor is driven by n steps, it can be detected quickly when step-out occurs.

Further, in the printing apparatus according to the present invention, each time the control unit drives the stepping motor by n (where n ≧ 1) steps, the encoder rotates the accumulated rotational amount of the rotating body in a predetermined period by the encoder. A rotation amount obtained by the product of k (where k> n) steps driven by the stepping motor in the predetermined period and the first rotation amount, or a rotation amount reflecting a margin in the calculated rotation amount is It is determined whether or not the stepping motor has been detected, and step out of the stepping motor is detected.
According to this configuration, every time the stepping motor is driven for n steps, the step-out is stepped out based on the comparison between the cumulative rotational amount of the rotating body predicted in the predetermined period and the actual cumulative rotational amount. Can be accurately detected. Further, the step-out can be detected when driving for a plurality of steps, and the processing load of the control unit is reduced as compared with the case where detection is performed every time one step is driven.

In the printing apparatus according to the aspect of the invention, when the control unit drives the stepping motor by k (where k> n) steps, the encoder rotates the rotating body as the rotation amount of the first rotation amount. The stepping motor step-out is detected by determining whether or not a rotation amount obtained by the product of k or a rotation amount reflecting a margin in the obtained rotation amount is detected.
According to this configuration, when the stepping motor is rotated by the number of k steps, it is possible to accurately detect the stepping motor step-out based on the comparison between the predicted rotation amount and the actual rotation amount.

In the printing apparatus according to the aspect of the invention, the control unit may perform the first predetermined period after the start of the driving of the stepping motor and the second predetermined period before the end of the driving of the stepping motor. The stepping motor is not detected as being out of step.
According to this configuration, it is possible to detect step out of the stepping motor by eliminating the influence of the gear backlash.

In the printing apparatus of the present invention, the print head is a line inkjet head, and the control unit drives the carriage on which the print head is mounted from a home position to a print position, or , And moving from the printing position to the home position.
According to this configuration, when the carriage on which the line inkjet head is mounted is moved by the stepping motor, it is possible to detect the step-out of the stepping motor.

In order to achieve the above object, the present invention is a step-out detection method, comprising a stepping motor, a carriage on which a print head is mounted, and moving according to the driving of the stepping motor, and a movement amount of the carriage And an encoder for detecting the amount of movement of the carriage detected by the encoder when the stepping motor is driven by a predetermined amount by the control unit. A step-out of the stepping motor is detected based on a comparison with a predicted movement amount of the carriage that is predicted when the stepping motor is driven by the predetermined amount.
Here, when the actual movement amount of the carriage when the stepping motor is driven by a predetermined amount is different from the predicted movement amount predicted when the stepping motor is not stepped out, the stepping motor has stepped out. there is a possibility. According to the above configuration, the printing apparatus detects the carriage movement detected by the encoder when the stepping motor is driven by a predetermined amount, and the carriage prediction that is predicted when the stepping motor is driven by the predetermined amount. A step-out of the stepping motor is detected based on the comparison with the movement amount. For this reason, it is possible to accurately detect the step-out of the stepping motor.

  According to the present invention, it is possible to accurately detect a step-out in a printing apparatus that moves a carriage by driving a stepping motor.

It is a side view of the printing apparatus which concerns on this embodiment. It is a top view of a printing apparatus. It is a perspective view of a carriage and other related members. It is a side view of a carriage and other related members. It is a perspective view of a carriage moving mechanism. FIG. 3 is a block diagram illustrating a functional configuration of the printing apparatus. 6 is a flowchart illustrating an operation of the printing apparatus. 6 is a flowchart illustrating an operation of the printing apparatus.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a side view schematically showing the internal structure of the printing apparatus 1 according to the present embodiment. FIG. 2 is a top view schematically showing the internal structure of the printing apparatus 1.
The printing apparatus 1 is a line inkjet printer, and prints an image on a print medium by ejecting ink from a print head 10 constituted by a line inkjet head while conveying the print medium on a conveyance path H.
In the following description using FIGS. 1 and 2, it is assumed that there is a front-rear direction in the direction indicated by the arrows in the drawings.

As shown in FIG. 1, the printing apparatus 1 includes a printing apparatus main body 11, and a roll paper storage unit 12 (FIG. 1) is provided at the rear of the printing apparatus main body 11.
The roll paper storage unit 12 is a part that stores the roll paper R that is a printing medium. The roll paper R is a sheet wound in a roll shape. For example, in addition to a paper in which plain paper or fine paper is wound in a roll shape, a fixed-size label with an adhesive on the back surface is used as a release paper ( There is a label paper that is rolled up in line with the mount.
Hereinafter, in the roll paper R, a cylindrical portion wound in a roll shape is expressed as a roll paper main body R1, and a portion pulled out from the roll paper main body R1 is expressed as a transport roll paper R2. The transport roll paper R2 is represented by a dotted line in FIG.
The roll paper storage unit 12 stores a roll paper main body R1. At that time, the roll paper rotating shaft 9 is fitted into a cylindrical core R3 formed at the center of the roll paper main body R1. The roll paper rotating shaft 9 is connected to a motor shaft of a transport motor 64 (FIG. 6), which will be described later, via a speed reduction mechanism (not shown), and is configured to rotate according to the drive of the transport motor 64. Then, the roll paper main body R1 rotates in conjunction with the rotation of the roll paper rotation shaft 9 fitted in the core R3 of the roll paper main body R1.
The transport roll paper R2 is drawn upward in the transport direction F from the roll paper main body R1 stored in the roll paper storage unit 12. A tension lever 13 is provided at the upper rear of the shaft of the roll paper body R1. The transported roll paper R2 drawn upward is brought into contact with the tension lever 13, bent by the tension lever 13, and then extended forward.
The tension lever 13 is a lever that prevents the slack by giving tension to the transported roll paper R2. The tension lever 13 is urged to rotate about the shaft 14 in a direction in which the transport roll paper R2 is stretched (direction indicated by an arrow Y1).

A paper guide portion 16 is provided in front of the tension lever 13. The paper guide unit 16 includes a lower paper guide unit 17 (FIG. 1), an upper paper guide unit 18 (FIG. 1), and a side paper guide unit 15 (FIG. 2). The lower paper guide unit 17 is a table that supports the transported roll paper R2 from below. The upper paper guide unit 18 is a member that is positioned above the transport roll paper R2 so as to face the lower paper guide unit 17 and includes the lift of the transport roll paper R2. The side paper guide unit 15 is a guide that extends along the conveyance direction F on both sides of the conveyed roll paper R2 to be conveyed, and is a member that suppresses meandering and conveyance deviation of the conveyed roll paper R2. It is.
A paper detector 19 (FIG. 1) is provided at the rear of the paper guide unit 16. The paper detector 19 is, for example, a transmissive sensor that includes a light emitting unit on the upper paper guide unit 18 side and a light receiving unit on the lower paper guide unit 17 side. Since the output value (detection voltage) indicating the amount of light received by the paper detector 19 varies depending on the presence or absence of the transport roll paper R2 at the position of the paper detector 19, the front and rear ends of the transport roll paper R2 using the paper detector 19 are used. Can be detected.

  A printing unit 21 that prints an image on the transported roll paper R2 is disposed in front of the paper guide unit 16. The printing unit 21 includes a platen 22 and a print head 10. The print head 10 according to the present embodiment ejects ink of four colors, C (cyan), M (magenta), Y (yellow), and K (black), to form dots on the printing surface of the transport roll paper R2. . The print head 10 ejects a nozzle section 24 that ejects K (black) ink, a nozzle section 25 that ejects C (cyan) ink, a nozzle section 26 that ejects M (magenta) ink, and a Y (yellow) ink. Nozzle portion 27 is provided. In the nozzle portions 24 to 27, a plurality of nozzles that eject ink are arranged in a row in the width direction of the transport roll paper R2. The nozzle rows of the nozzle portions 24 to 27 of the print head 10 are formed to have a width wider than at least the printable range of the transport roll paper R2. In the present embodiment, a configuration example is described in which the nozzle portions 24, 25, 26, and 27 are arranged in this order along the conveyance direction F of the conveyance roll paper R2, but the arrangement order of the nozzles of each color in the conveyance direction F is arbitrary. .

The platen 22 has a plane disposed along the transport direction F. This plane faces the print head 10. The platen 22 is fixed to the frame of the printing apparatus 1 (not shown) and supports the transport roll paper R2 from below. The plane of the platen 22 is substantially horizontal when the printing apparatus 1 is installed and used.
A conveyor belt 30 (FIG. 1) (not shown) is disposed on the plane of the platen 22. The conveyor belt 30 is a wide endless belt, and is arranged so as to pass on the plane of the platen 22 and to wrap around the platen 22. Of the surface of the conveyor belt 30, at least the surface facing upward on the plane of the platen 22 is a rough surface having a high friction coefficient. The conveyor belt 30 is preferably made of an elastic material such as rubber or synthetic resin. Below the platen 22, a conveyance motor 31 (FIG. 6) and a conveyance unit 32 having a drive mechanism that moves the conveyance belt 30 by the rotational force of the conveyance motor 31 are arranged. The transport motor 31 rotates under the control of the control unit 50 described later. The drive mechanism (not shown) provided in the transport unit 32 includes various gears that mesh with the output shaft of the transport motor 31, rollers that move the transport belt 30, and the transport belt 30 is moved by the rotation of the transport motor 31. The transport roll paper R2 is transported in the transport direction F. The conveyance direction and conveyance speed of the print medium accompanying the movement of the conveyance belt 30 are detected using a rotary encoder 60 (FIG. 6) described later.

  On the upstream side of the print head 10 in the transport path H, a transport roller 34 (FIG. 1) is disposed facing the platen 22. The conveyance roller 34 is a driven roller that is rotatably supported by the frame of the printing apparatus 1, and is urged toward the plane of the platen 22. In the transport path H, the transport roll paper R2 is sandwiched between the transport roller 34 and the transport belt 30 and is transported in the transport direction F as the transport belt 30 moves. In addition, a plurality of rollers (not shown) that press the transport roll paper R <b> 2 so as not to float from the transport belt 30 are disposed between the nozzle portions 24, 25, 26, and 27 of the print head 10.

  A cutter unit 37 is disposed on the downstream side of the print head 10 in the conveyance path H. The cutter unit 37 includes a fixed blade and a movable blade arranged with the conveyance path H interposed therebetween, and the movable blade is connected to a cutter drive motor 65 (FIG. 6) via a gear or the like. When the cutter drive motor 65 is driven, the movable blade moves to the fixed blade side and cuts the transported roll paper R2. The cutter unit 37 may cut a part of the transport roll paper R2 in the width direction, or may completely cut the transport roll paper R2. The printing apparatus 1 uses the cutter unit 37 to cut the transport roll paper R2 printed by the print head 10 into a predetermined length and discharges it from the paper discharge outlet.

A winding unit 42 (shown only in FIG. 1) can be attached to and detached from the front surface of the printing apparatus 1. The take-up unit 42 includes a take-up drum 43 that takes up the transported roll paper R2 discharged from the paper discharge port, and a drive unit (not shown) that rotates the take-up drum 43. The winding drum 43 is driven by a rotational force transmitted from the conveyance motor 31 of the printing apparatus 1 via a gear train (not shown). The winding drum 43 may be configured to be driven by a motor independent of the transport motor 31. The take-up drum 43 rotates in the direction indicated by the arrow A in the drawing to take up the transport roll paper R2. When the winding unit 42 is used, the printing apparatus 1 does not cut the transport roll paper R2 by the cutter unit 37, and discharges the transport roll paper R2 from the paper discharge port in a long state.
A control board 44 is provided on the right side of the paper guide 16 in the forward direction. On the control board 44, a CPU, a RAM, and other circuits of the control unit 50 described later are mounted.

As shown in FIGS. 1 and 2, the print head 10 is mounted on a carriage 70. As shown in FIG. 2, the carriage 70 is configured to be movable in the main scanning forward direction G1 or the main scanning reverse direction G2, and as shown in FIG. It is transported between the printing position PP and the home position HP.
The printing position PP is a position facing the platen 22 and is a position where an image can be printed on the printing surface by ejecting ink to the transport roll paper R2. When printing an image, at the print position PP, the print head 10 is moved downward by a predetermined mechanism and disposed at an appropriate position.
The home position HP is a retracted position of the print head 10 provided at a place avoiding the above-described print position PP. When an instruction to turn off the power is given, or when a process related to printing is not executed for a predetermined period and the process shifts to the standby mode, the control unit 50 described later moves the carriage 70 to the home position HP, and the print head 10 Is positioned at the home position HP. Next, the control unit 50 moves a cap (not shown) and covers the nozzle formation surface of the print head 10 with the cap. As a result, drying of the ink staying at the nozzle is suppressed.
Further, cleaning and flushing are performed at the home position HP.
Cleaning means that the ink staying inside the nozzles of the print head 10 is forced to stay in the nozzles in order to prevent the viscosity from increasing and the ejection failure from the nozzles from occurring. This is a suction operation. During cleaning, the control unit 50 described later moves a cap (not shown) and covers the nozzle formation surface of the print head 10 with the cap. Next, the control unit 50 drives a pump (not shown) connected to the cap to apply a negative pressure to the nozzle forming surface of the print head 10 to forcibly suck the ink remaining in the nozzles.
The flushing is an operation performed to suppress an increase in the viscosity of the ink accumulated in the nozzles of the print head 10.
At the time of flushing, the control unit 50 causes a cap (not shown) to eject a predetermined amount of ink from the nozzle a predetermined number of times, and replaces the ink remaining inside the nozzle with new ink.

FIG. 3 is a perspective view showing details of the carriage 70 and related members, and FIG. 4 is a side view showing details of the carriage 70 and related members.
FIG. 5 is a perspective view of a carriage moving mechanism 71 that moves the carriage 70.
As shown in FIGS. 3 and 4, the carriage 70 includes a carriage body 73 that houses the print head 10 therein. On the upper surface of the carriage body 73, an opening for accessing the print head 10 accommodated in the carriage body 73 is formed. The carriage body 73 is provided with a carriage cover 74 that closes an opening formed on the upper surface so as to be freely opened and closed.
As shown in FIGS. 3 and 4, the printing apparatus 1 includes two carriage shafts 76a and 76b extending in directions corresponding to the main scanning forward direction G1 and the main scanning reverse direction G2. The carriage 70 is supported by the carriage shafts 76a and 76b while being movable along the carriage shafts 76a and 76b. More specifically, in the carriage main body 73, a carriage support portion 78 in which a through hole 77 (FIG. 3) through which the carriage shaft 76a passes is formed on one (rightward) side surface along the main scanning positive direction G1. Are provided apart from each other in the main scanning positive direction G1. Similarly, although not shown, in the carriage main body 73, a carriage support portion 78 in which a through-hole 77 through which the carriage shaft 76b passes is formed on the other side surface (on the left side in the main scanning direction G1). Are provided apart from each other in the main scanning positive direction G1. The carriage main body 73 is movable in the main scanning forward direction G1 or the main scanning reverse direction G2 while the four carriage support portions 78 restrict the vertical and forward movements of the carriage main body 73. Is supported.

3-5, below the carriage shaft 76a, it extends along the carriage shaft 76a while being wound around the first pulley 80 (particularly, see FIG. 5) and the second pulley 81. An endless belt 82 is provided. The endless belt 82 moves in the arrow B direction or the arrow C direction as the first pulley 80 rotates. In the carriage main body 73, a belt fixing portion 84 fixed to a part of the endless belt 82 is provided at the center lower portion of the right side surface in the main scanning positive direction G1. As the endless belt 82 moves, the carriage 70 moves through the belt fixing portion 84. More specifically, when the endless belt 82 moves in the arrow B direction, the carriage 70 moves in the main scanning positive direction G1 along with this movement. On the other hand, when the endless belt 82 moves in the arrow C direction, the carriage 70 moves in the main scanning reverse direction G2 along with this movement.
As shown in FIGS. 3 and 4, a carriage moving mechanism 71 is provided at a position corresponding to the first pulley 80. Hereinafter, the carriage moving mechanism 71 will be described in detail.

The carriage moving mechanism 71 is a mechanism that moves the carriage 70 by moving the endless belt 82.
The carriage moving mechanism 71 includes a power transmission mechanism 79 that includes a plurality of gears.
As shown in FIG. 5, the power transmission mechanism 79 includes a drive gear 86. The drive gear 86 is a pinion provided on the motor shaft of the carriage movement motor 66 (FIG. 6). In the present embodiment, the carriage movement motor 66 is a stepping motor. As will be described later, the printing apparatus 1 is configured such that the carriage 70 moves in accordance with the driving of the carriage movement motor 66. Since the stepping motor can be precisely controlled by a pulse signal, the positioning of the carriage 70 can be precisely controlled by configuring the carriage moving motor 66 with the stepping motor.
A large gear 87 a of a two-stage gear 87 is engaged with the drive gear 86. The two-stage gear 87 includes a small gear 87b provided coaxially with the large gear 87a, and a pulley driving gear 88 is engaged with the small gear 87b.
The pulley drive gear 88 is a gear provided coaxially with the first pulley 80 and fixed to the first pulley 80. The first pulley 80 is driven in synchronization with the rotation of the pulley drive gear 88.
When the motor shaft of the motor rotates as the carriage movement motor 66 is driven, the drive gear 86 provided on the motor shaft rotates. In accordance with the rotation of the drive gear 86, the two-stage gear 87 meshed with the drive gear 86 and the pulley drive gear 88 meshed with the two-stage gear 87 are rotated with the rotation speed adjusted according to the gear ratio of each gear. To do. Then, the first pulley 80 rotates in synchronization with the rotation of the pulley drive gear 88, and the endless belt 82 moves in a direction corresponding to the rotation direction in accordance with this rotation.

Further, as shown in FIG. 5, the relay gear 90 is engaged with the large gear 87 a of the two-stage gear 87, and the driven gear 91 (rotary body) is engaged with the relay gear 90. The driven gear 91 rotates with the rotation speed adjusted according to the gear ratio of each gear through the drive gear 86, the large gear 87a of the two-stage gear 87, and the relay gear 90 as the carriage movement motor 66 is driven. To do.
A rotary encoder 92 (encoder) is provided at a position corresponding to the driven gear 91.
The rotary encoder 92 is a light transmission encoder. The rotary encoder 92 detects the amount of movement of the carriage 70 by detecting the amount of rotation of the driven gear 91.
Hereinafter, the configuration of the rotary encoder 92 will be described in detail. The rotary encoder 92 includes a wheel 93. The wheel 93 is provided coaxially with the driven gear 91 and fixed to the driven gear 91, and rotates in synchronization with the rotation of the driven gear 91. Although not shown, slits are provided on the outer edge of the wheel 93 at equal intervals in the circumferential direction.
The rotary encoder 92 includes an optical processing unit 94. The optical processing unit 94 includes a light emitting unit 96 and a light receiving unit 97.
The light emitting unit 96 includes a light source such as an LED, and emits light from the light source. The light receiving unit 97 includes a light receiving element such as a photodiode, and receives light emitted from the light emitting unit 96. The light emitted from the light emitting unit 96 is received by the light receiving unit 97 through the slit portion of the wheel 93 located at the corresponding position.
The detection value of the light receiving unit 97 is input to a predetermined signal processing circuit, processed by the signal processing circuit, and input to a signal processing circuit 61 described later as two types of square waves.

FIG. 6 is a block diagram illustrating a functional configuration of the printing apparatus 1.
As shown in FIG. 6, the printing apparatus 1 is connected to a host PC 5, and the printing system 2 is configured by these apparatuses.
The host PC 5 is installed with an application and a printer driver related to the control of the printing apparatus 1, and controls the printing apparatus 1 by transmitting a control command to the printing apparatus 1 using the functions of these programs.

As illustrated in FIG. 6, the printing apparatus 1 includes a control unit 50 that controls each unit of the printing apparatus 1. An I / F (interface) 51 and a storage unit 52 connected to the host PC 5 are connected to the control unit 50. The I / F 51 is wired or wirelessly connected to the host PC 5.
The control unit 50 includes a CPU, a ROM, a RAM, and the like as a calculation execution unit (not shown). In the ROM of the control unit 50, firmware executable by the CPU, data related to the firmware, and the like are stored in a nonvolatile manner. The RAM temporarily stores data related to firmware executed by the CPU. The control unit 50 may include other peripheral circuits. The storage unit 52 stores various programs and data in a nonvolatile manner. The storage unit 52 stores control programs executed by the control unit 50, data related to these control programs, and commands and data received by the printing apparatus 1 from the host PC 5.
An operation detection unit 55 that detects an operation of an operation switch 54 provided on a switch panel (not shown) is connected to the control unit 50. The operation switch 54 is, for example, a paper feed switch for instructing a transport operation of the printing apparatus 1, a cut switch for instructing an operation of the cutter unit 37, a setting switch for performing various settings, and the like.
In addition, a sensor driving unit 56 that acquires a detection value of the paper detector 19 is connected to the control unit 50. Under the control of the control unit 50, the sensor driving unit 56 supplies driving power to the paper detector 19 to emit light, acquires the detection voltage output by the paper detector 19 according to the amount of received light, and detects the detection voltage. Is output to the control unit 50.

Further, a signal processing circuit 59 is connected to the control unit 50, and a rotary encoder 60 is connected to the signal processing circuit 59. The rotary encoder 60 is a rotary encoder that is used to detect the conveyance direction and conveyance speed of the print medium. The signal processing circuit 59 performs predetermined signal processing on the detection value of the rotary encoder 60 and outputs the result to the control unit 50. The control unit 50 cooperates with an encoder counter (not shown) to detect the conveyance direction and conveyance speed of the print medium based on the input value from the signal processing circuit 59.
A signal processing circuit 63 is connected to the control unit 50, and a rotary encoder 62 is connected to the signal processing circuit 63. The rotary encoder 62 is a rotary encoder used for detecting the rotation angle of the tension lever 13. The signal processing circuit 63 performs predetermined signal processing on the detection value of the rotary encoder 62 and outputs the result to the control unit 50. The control unit 50 detects the rotation angle of the tension lever 13 based on the input value from the signal processing circuit 63 in cooperation with an encoder counter (not shown).
The rotary encoder 92 and the signal processing circuit 61 will be described later.

As shown in FIG. 6, a motor driver 67 that drives the transport motor 31, the transport motor 64, the cutter drive motor 65, and the carriage movement motor 66 is connected to the control unit 50.
As described above, the transport motor 31 is a motor that transports the print medium by moving the transport belt 30. The conveyance motor 31 is configured by a brushless DC motor. The control unit 50 controls the motor driver 67 to supply a drive current from the motor driver 67 to the transport motor 31 to drive the transport motor 31.
Further, as described above, the transport motor 64 is a motor that rotates the roll paper body R1 by rotating the roll paper rotation shaft 9 fitted in the core R3 of the roll paper body R1. When the roll paper main body R1 rotates in a direction according to the conveyance direction F, the conveyance roll paper R2 is pulled out from the roll paper main body R1. On the other hand, when the roll paper main body R1 rotates in the direction opposite to the direction according to the conveyance direction F, the conveyance roll paper R2 is drawn into the roll paper main body R1. The conveyance motor 64 is configured by a brushless DC motor. The control unit 50 controls the motor driver 67 to supply a drive current from the motor driver 67 to the transport motor 64 to drive the transport motor 64.
As described above, the cutter drive motor 65 is a motor that moves the movable blade of the cutter unit 37 to cut the print medium. The cutter drive motor 65 is configured by a stepping motor. The control unit 50 controls the motor driver 67 to output a driving pulse from the motor driver 67 to the cutter driving motor 65 to drive the cutter driving motor 65.
The carriage movement motor 66 will be described later.

In addition, a head driver 68 that drives the print head 10 is connected to the control unit 50. The control unit 50 controls the head driver 68 to supply ink to the print head 10 from an ink tank (not shown) and a piezo element provided in the nozzle units 24 to 27 of the print head 10. A voltage is supplied to (not shown) to operate them. Thereby, ink droplets are ejected from the nozzles of the nozzle portions 24 to 27 to form dots.
During the conveyance of the print medium accompanying the printing of the image on the print medium, the control unit 50 detects the position of the print medium in the conveyance path H based on the detection value of the paper detector 19 and the detection values of other sensors. Further, the control unit 50 monitors the conveyance speed of the print medium based on the detection value of the rotary encoder 60. In addition, the control unit 50 monitors whether or not the conveyance speed of the print medium is appropriate based on the rotation angle of the tension lever 13 detected by the detection value of the rotary encoder 62, and adjusts the conveyance speed.

Next, the rotary encoder 92 and the carriage movement motor 66 will be described in detail.
As described above, the carriage movement motor 66 is composed of a stepping motor. Accordingly, the carriage movement motor 66 is driven in synchronization with the pulse power. That is, the motor shaft of the carriage movement motor 66 rotates by one step angle (for example, “0.72 ° (0.72 degrees)”) in response to the input of one pulse signal. In the following description, the rotation of the motor shaft by one step angle in response to the input of one pulse signal for the carriage movement motor 66 is appropriately expressed as “the carriage movement motor 66 is driven by one step”. Further, outputting the pulse signal to the carriage movement motor 66 and rotating the motor by one step angle is appropriately expressed as “driving the carriage movement motor 66 by one step” as appropriate.
Further, in the following description, the rotational direction in which the endless belt 82 is moved in the arrow B direction with respect to the rotational direction of the drive gear 86 is expressed as a “first positive direction” (see FIG. 5). As the endless belt 82 moves in the direction of arrow B, the carriage 70 moves toward the printing position PP. Further, regarding the rotation direction of the drive gear 86, the rotation direction in which the endless belt 82 is moved in the direction of arrow C is expressed as “first reverse direction” (see FIG. 5). As the endless belt 82 moves in the direction of arrow C, the carriage 70 moves toward the home position HP.
In addition, regarding the rotation direction of the driven gear 91, the rotation direction when the endless belt 82 rotates in accordance with the movement in the arrow B direction is expressed as a “second positive direction” (see FIG. 5). Further, with respect to the rotation direction of the driven gear 91, the rotation direction when rotating with the movement of the endless belt 82 in the arrow C direction is expressed as "second reverse direction" (see FIG. 5).

Here, as described above, the detection value of the rotary encoder 92 is input to the control unit 50 after being subjected to predetermined signal processing by the signal processing circuit 61. Then, the control unit 50 detects the rotation amount of the driven gear 91 based on the detection value of the rotary encoder 92. Here, since the driven gear 91 rotates with the rotation of the first pulley 80, the control unit 50 detects the amount of movement of the carriage 70 by detecting the amount of rotation of the driven gear 91.
In the present embodiment, the amount of rotation of the driven gear 91 is expressed as an integer value in a predetermined unit (for convenience, the unit is expressed as “ep”). The value indicating the amount of rotation increases by “1 (ep)” each time the driven gear 91 rotates by an angle A1 in the second positive direction. On the other hand, every time the driven gear 91 rotates by the angle A1 in the second reverse direction, the value decreases by “1 (ep)”.
In particular, in the present embodiment, when the carriage 70 (= endless belt 82) moves “0.08 mm” in the direction toward the printing position PP, the driven gear 91 moves in the second positive direction according to the movement by “angle”. “A1 × 3” is configured to rotate. As a result, as the carriage 70 moves “0.08 mm” in the direction toward the printing position PP, the value indicating the rotation amount of the driven gear 91 detected by the control unit 50 increases by “3 (ep)”. . On the other hand, when the carriage 70 moves “0.08 mm” in the direction toward the home position HP, the driven gear 91 rotates in the second reverse direction by “angle A1 × 3” degrees in accordance with the movement. ing. As a result, the value indicating the rotation amount of the driven gear 91 detected by the control unit 50 decreases by “3 ep”.

Further, in the present embodiment, the amount of movement of the carriage 70 (= the amount of movement of the endless belt 82) when the motor is rotated by one step angle in the first positive direction with the carriage moving motor 66 not stepping out. Is “0.08 mm”. The amount of movement of the carriage 70 when the carriage movement motor 66 rotates by one step angle in the first reverse direction is also “0.08 mm”.
Therefore, when the carriage moving motor 66 is not out of step, the control unit 50 outputs one pulse signal for rotating the carriage moving motor 66 in the first positive direction. It moves “0.08 mm” toward the position PP. Along with this movement, the value indicating the amount of rotation of the driven gear 91 detected by the control unit 50 increases by “3 ep”.
Thus, as the carriage movement motor 66 is driven for one step, the detected rotation amount of the driven gear 91 increases by “3 ep”, but this increase “3 ep” is the “first rotation amount”. It corresponds to.
The gear ratio of each gear of the power transmission mechanism 79 is a gear ratio that realizes the above configuration. That is, the gear ratio of each gear of the power transmission mechanism 79 is a gear ratio for moving the carriage 70 “0.08 mm” in a predetermined direction in accordance with the driving of the carriage moving motor 66 for one step. The gear ratio of each gear of the power transmission mechanism 79 is a gear ratio for rotating the driven gear 91 by “angle A1 × 3” degrees in a predetermined direction as the carriage 70 moves by “0.08 mm”. ing.

Incidentally, in the printing apparatus 1 according to the present embodiment, the carriage movement motor 66 is configured by a stepping motor. With this configuration, precise position control of the carriage 70 is possible.
The printing apparatus 1 has a function of detecting step out of the carriage movement motor 66. The printing apparatus 1 includes an operation mode D1 and an operation mode D2 as operation modes when detecting step-out. The user can apply the operation mode D1 and the operation mode D2 at the same time, or switch the operation mode and apply it.
Hereinafter, first, an operation when the printing apparatus 1 detects a step-out in the operation mode D1 will be described.

FIG. 7 is a flowchart showing the operation of the printing apparatus 1 in the operation mode D1.
In the operation mode D1, a predetermined number n (an integer of n ≧ 1) pulse signals are output to the carriage movement motor 66, and every time the motor is driven for n steps, the step-out detection for the n steps is executed. It is an operation mode. In this embodiment, a case where n = 2 is shown.
In the operation mode D1, the control unit 50 executes the process shown in the flowchart of FIG. 7 when moving the carriage 70 from the home position HP to the print position PP.
As shown in FIG. 7, the control unit 50 controls the motor driver 67 so as to move the carriage 70 toward the printing position PP, and outputs two (n = 2) pulse signals to the carriage movement motor 66. Output (step SA1). In the following description, it is assumed that the pulse signal input to the carriage movement motor 66 is a pulse signal for rotating the drive gear 86 in the first positive direction.
As described above, when the carriage movement motor 66 is not out of step, the value indicating the rotation amount of the driven gear 91 detected with the output of 2 (two) pulse signals is “3 × 2”. (Ep) ", expected to increase. The amount of rotation “3 × 2 (ep)” predicted to increase corresponds to the “predicted amount of rotation of the rotating body”.
Next, the control unit 50 obtains how much the value indicating the rotation amount of the driven gear 91 has increased with the output of the two pulse signals in step SA1 based on the detection value of the rotary encoder 92 ( Step SA2). The amount of rotation detected for the increase corresponds to “the amount of rotation of the rotating body detected by the encoder”. That is, the value detected in step SA2 is the rotation amount corresponding to the actual movement amount of the carriage 70.
Next, the control unit 50 determines whether or not the value detected in Step SA2 is less than “3 × 2 (ep)” (predicted rotation amount) that reflects the margin (Step SA3). In this example, a value that is 1/3 of the predicted rotation amount is a value that reflects a margin in the predicted rotation amount. The method of reflecting the margin with respect to the predicted rotation amount is not limited to this, but is based on the actual positioning tolerance of the carriage 70, the margin of the operation mode 2 described later, and the like. For example, a value obtained by subtracting a predetermined value (for example, “2”) from the predicted rotation amount may be a value reflecting a margin in the predicted rotation amount. Also, the margin need not be reflected.
When the carriage movement motor 66 is out of step, the carriage 70 is not transported normally, and the value detected in step SA2 reflects the margin in the predicted rotation amount (in this example, 3 × 2 × 1 / 3 = 2 (ep)). Based on this, in the present embodiment, it is determined that the step-out has occurred when the value detected in step SA2 is less than “3 × 2 × 1/3 = 2 (ep)”.

If the value detected in step SA2 is not less than “2 (ep)” (step SA3: NO), it is determined that no step-out has occurred, and the control unit 50 moves the carriage 70 to the print position PP. Is determined (step SA4). The determination is performed as follows, for example. That is, a sensor that detects that the carriage 70 is positioned at the print position PP is provided, and the control unit 50 performs the above determination based on the detection value of the sensor. Further, for example, the number of pulse signals necessary for moving the carriage 70 from the home position HP to the printing position PP is set in advance, and the control unit 50 has completed the output of the pulse signals for the number of outputs. The above determination is made by determining whether or not.
When the movement of the carriage 70 to the print position PP is completed (step SA4: YES), the control unit 50 ends the process. On the other hand, when the movement of the carriage 70 to the printing position PP has not been completed (step SA4: NO), the control unit 50 returns the processing procedure to step SA1 and outputs a pulse signal of 2 to the carriage movement motor 66.

On the other hand, if the value detected in step SA2 is less than “3 × 2 × 1/3 = 2 (ep)” in step SA3 (step SA3: YES), the controller 50 causes the carriage movement motor 66 to step out. (Step SA5). Next, the control unit 50 executes a process defined as a process to be performed when there is a possibility that the carriage movement motor 66 has stepped out (step SA6). For example, the control unit 50 stops the movement of the carriage 70 and drives an LED or a display panel (not shown) to notify the user that the carriage movement motor 66 may be out of step. . For example, the control unit 50 transmits predetermined data to the host PC 5. The host PC 5 that has received the data temporarily stops the output of the control command to the printing apparatus 1 and uses the display panel or the like of the host PC 5 to indicate that there is a possibility that the carriage movement motor 66 has stepped out. Inform the user.
Thus, in the operation mode D1, detection of step-out for two steps is executed every time the carriage movement motor 66 is driven for two steps. For this reason, when step-out actually occurs, it can be detected quickly.

The operation of the printing apparatus 1 in the operation mode D1 has been described above using the flowchart of FIG.
Further, in the first predetermined period after the driving of the carriage movement motor 66 is started and in the second predetermined period before the end of the driving of the carriage movement motor 66, the step-out of the carriage movement motor 66 is detected. It may not be performed.
The first predetermined period is, for example, a period from the first step to the 25th step when driving for the first step of the carriage movement motor 66 is the first step. The second predetermined period is, for example, a period from the (X-25) th step to the X step when the last one step of the carriage movement motor 66 is driven as the X step. With such a configuration, it is possible to detect the step-out of the carriage movement motor 66 by eliminating the influence of the gear backlash.

Next, the operation of the printing apparatus 1 in the operation mode D2 will be described.
The operation mode D2 is a mode for detecting step out of k steps (k> n) larger than the n steps of the operation mode D1.
In the operation mode D2, when the carriage 70 moves from the home position HP to the print position PP, the step-out detection described below is executed.

FIG. 8 shows the printing apparatus 1 in the case where the step-out detection is performed at the output timing of the pulse signal of the kth pulse (where k is a positive integer) and the pulse signal of the kth pulse is output. It is a flowchart which shows operation | movement.
As shown in FIG. 8, the control unit 50 controls the motor driver 67 so as to move the carriage 70 toward the printing position PP, and outputs a k-th pulse signal to the carriage movement motor 66 (step). SB1).
Next, the control unit 50 acquires the accumulated rotation amount of the driven gear 91 for k steps, which is detected according to the output of the pulse signal of the first pulse to the k-th pulse in a predetermined period (step SB2). . The control unit 50 stores the accumulated rotation amount of the driven gear 91 in a predetermined storage area of a work area such as a RAM.
As described above, when the carriage movement motor 66 has not stepped out, the value indicating the rotation amount of the driven gear 91 increases by “3 × k (ep)” with the output of the pulse signal for k pulses. That is expected. The amount of rotation “3 × k (ep)” that is predicted to increase corresponds to the “predicted amount of rotation of the rotating body”.
Next, the control unit 50 determines whether or not the value detected in step SB2 is less than a value that reflects the margin in “3 × k (ep)” (predicted rotation amount) (step SB3). In this example, a value obtained by subtracting “9” from the predicted rotation amount is set to a value reflecting a margin in the predicted rotation amount. That is, the value reflecting the margin in the expected rotation amount is “3 × k−9 (ep)”. The method of reflecting the margin with respect to the predicted rotation amount is not limited to this, but is based on the actual positioning tolerance of the carriage 70, the margin of the operation mode 1 described above, and the like. Also, the margin need not be reflected.
When the carriage movement motor 66 is out of step, the carriage 70 is not normally conveyed, and the value detected in step SB2 reflects a margin in the predicted rotation amount (in this example, 3 × k−9 ( ep)). Based on this, in the present embodiment, it is determined that the step-out has occurred when the value detected in step SA2 is less than “3 × k−9 (ep)”.

In step SB3, if the value detected in step SB2 is not less than “3 × k−9 (ep)” (step SB3: NO), step-out is not detected. The key detection process ends.
On the other hand, in step SB3, when the value detected in step SB2 is less than “3 × k−9 (ep)” (step SB3: YES), the controller 50 indicates that the carriage moving motor 66 has stepped out. It is determined that there is a possibility (step SB4). Next, the control unit 50 executes a process defined as a process to be performed when there is a possibility that the carriage movement motor 66 has stepped out (step SB5).
Similarly to the operation mode D1, the operation mode D2 outputs a predetermined number n of pulse signals to the carriage moving motor 66, and every time the stepping motor is driven n times, the step out of k steps is performed. Detection may be performed.
For example, in the operation mode D2, the controller 50 outputs the accumulated rotation amount from the first step to the k step related to the output of the pulse signal every time three pulse signals are output (n = 3). And step-out detection may be executed based on the comparison with the predicted rotation amount. More specifically, the control unit 50 is based on a comparison between the accumulated rotation amount from the first step to the third (k = 3) step and the predicted rotation amount at the timing when the pulse signal of the third pulse is output. Step-out detection is performed, and at the timing when the pulse signal of the sixth pulse is output, the accumulated rotation amount from the first step to the sixth step (k = 6) is compared with the predicted rotation amount. Step-out detection may be performed such that step-out detection is performed.
In this case, the control unit 50 further compares the accumulated rotation amount for the latest 25 steps (k = 25) with the predicted rotation amount every time three pulse signals are output after the 27th step. A configuration in which step-out detection is performed based on this may be used.
As described above, in the operation mode D2, it is possible to detect the cumulative step out for the driving step, and the control unit 50 as compared with the case where the step out for the step is detected every time the step is driven. The processing load is reduced. Further, by applying the operation mode 2 at the same time as the operation mode 1, the detection accuracy of the step-out can be improved and the detection efficiency can be improved.

  In the first predetermined period after the driving of the carriage movement motor 66 is started and in the second predetermined period before the end of the driving of the carriage movement motor 66, the step-out of the carriage movement motor 66 is detected. It may not be performed.

As described above, the control unit 50 of the printing apparatus 1 according to the present embodiment performs the following processing when the carriage movement motor 66 configured by the stepping motor is driven by a predetermined amount. That is, the control unit 50 predicts when the carriage movement motor 66 detected by the rotary encoder 92 (the amount of rotation of the driven gear 91) and the carriage movement motor 66 are driven by the predetermined amount without being stepped out. The step-out is detected based on the comparison with the predicted movement amount of the carriage 70 (the rotation amount predicted for the driven gear 91).
According to this configuration, the printing apparatus 1 can accurately detect the step-out of the carriage movement motor 66 that is a stepping motor based on the detection value of the rotary encoder 92.

In the printing apparatus 1, when the carriage moving motor 66 is driven by one step without being stepped out, the detected rotation amount of the driven gear 91 (rotary body) is “3 (ep)” (the first). 1 rotation amount) is increased. Then, the control unit 50 detects the rotation amount of the driven gear 91 (rotary body) detected by the rotary encoder 92 when the carriage movement motor 66 is driven by a predetermined number of steps, and the carriage movement motor 66 by the predetermined number of steps. Based on a comparison between the predetermined number of steps and the predicted rotation amount of the driven gear 91 predicted based on the relationship between the first rotation amount (“3 (ep)”) and A step-out of the moving motor 66 is detected.
According to this configuration, when the carriage moving motor 66 is driven by one step without being stepped out, “3 (ep)” (first) is increased by the rotary encoder 92 as the amount of rotation of the driven gear 91. Using the configuration in which the rotation amount) is detected, it is possible to accurately detect the step-out of the carriage movement motor 66 based on a comparison between the actual rotation amount of the driven gear 91 and the predicted rotation amount of the driven gear 91. .

Further, in the present embodiment, the power transmission mechanism 79 rotates the driven gear 91 by “3 (ep)” in accordance with the driving of the carriage movement motor 66 that is not out of step for one step.
According to this configuration, when the carriage moving motor 66 is driven by one step without being stepped out, a configuration in which “3 (ep)” is detected as the amount of rotation of the rotating body by the rotary encoder 92. This can be realized using the power transmission mechanism 79.

In the present embodiment, in the operation mode D1, the control unit 50 sets the rotation amount of the driven gear 91 by the rotary encoder 92 every time the carriage moving motor 66 is driven by n (in the above example, “2”) steps. , “3 × n (ep)” or “3 × n (ep)” is determined whether or not the rotation amount reflecting the margin is detected, and the step-out of the carriage movement motor 66 is detected.
According to this configuration, since the step-out is detected every time the carriage movement motor 66 is driven n steps, it can be quickly detected when the step-out occurs.

Further, in the present embodiment, when the carriage movement motor 66 is driven by k steps, the control unit 50 obtains the rotation amount of the driven gear 91 by the product of “3 (ep)” and k by the rotary encoder 92. A step-out of the carriage movement motor 66 is detected by determining whether or not a rotation amount that is obtained or a rotation amount that reflects a margin in the calculated rotation amount is detected.
According to this configuration, step-out can be detected when driving for a plurality of steps, and the processing load of the control unit 50 is reduced as compared with the case where detection is performed every time n steps are driven.

In the present embodiment, the controller 50 controls the motor during the first predetermined period after the start of driving the carriage movement motor 66 and the second predetermined period before the end of driving the motor. It may be a configuration that does not detect step-out.
According to this configuration, the step-out of the carriage movement motor 66 can be detected without the influence of the gear backlash.

The above-described embodiment is merely an aspect of the present invention, and can be arbitrarily modified and applied within the scope of the present invention.
For example, in the above-described embodiment, the step-out detection is performed when the carriage 70 is moved in the direction toward the print position PP. However, the step-out detection is also performed when the carriage 70 is moved in the reverse direction. There may be.
In the above-described embodiment, the printing apparatus 1 is a line inkjet printing apparatus. However, any printing method of the printing apparatus 1 may be used. That is, the present invention is applicable to a printing apparatus that moves a carriage by a stepping motor.
Each functional block shown in FIG. 6 can be arbitrarily realized by cooperation of hardware and software, and does not suggest a specific hardware configuration. Further, each function of the printing apparatus 1 may be provided to another apparatus externally connected to the apparatus. The printing apparatus 1 may execute various processes by executing a program stored in an externally connected storage medium.

  DESCRIPTION OF SYMBOLS 1 ... Printing apparatus, 2 ... Printing system, 10 ... Print head, 21 ... Printing part, 50 ... Control part, 66 ... Carriage movement motor (stepping motor), 70 ... Carriage, 79 ... Power transmission mechanism, 91 ... Drive gear, 92: Rotary encoder (encoder).

Claims (11)

Stepper motor,
A carriage mounted with a print head and moving in accordance with the driving of the stepping motor;
An encoder for detecting the amount of movement of the carriage;
The amount of movement of the carriage detected by the encoder when the stepping motor is driven by a predetermined amount, and the prediction of the carriage that is predicted when the stepping motor is driven by the predetermined amount without being stepped out Based on the comparison with the movement amount, a control unit that detects the step-out of the stepping motor;
A printing apparatus comprising: The encoder is
A rotary encoder that detects the amount of movement of the carriage by detecting the amount of rotation of a rotating body that rotates according to the driving of the stepping motor;
The controller is
The amount of rotation of the rotating body detected by the encoder when the stepping motor is driven by a predetermined amount, and the amount of rotation of the rotating body predicted when the stepping motor is driven by a predetermined amount without being stepped out. The printing apparatus according to claim 1, wherein a step-out of the stepping motor is detected based on a comparison with a predicted rotation amount. When the stepping motor is driven by one step without being stepped out, the first rotation amount is detected as the rotation amount of the rotating body by the encoder.
The controller is
A rotation amount of the rotating body detected by the encoder when the stepping motor is driven by a predetermined number of steps;
When the stepping motor is driven by the predetermined number of steps, the predicted rotation amount of the rotating body predicted based on the relationship between the predetermined step number and the first rotation amount;
The printing apparatus according to claim 2, wherein a step-out of the stepping motor is detected based on the comparison. The rotating body is a driven gear connected to a driving gear provided on a motor shaft of the stepping motor via a power transmission mechanism,
4. The printing according to claim 3, wherein the power transmission mechanism rotates the driven gear by the first rotation amount in accordance with driving of the stepping motor for one step that is not out of step. 5. apparatus. The controller is
Rotation obtained by the product of the number of k steps (where k> 1) driven by the stepping motor in the predetermined period and the first rotation amount as the cumulative rotation amount of the rotating body in the predetermined period by the encoder. 5. The printing according to claim 3, wherein a step-out of the stepping motor is detected by determining whether or not a rotation amount that reflects a margin is detected in the amount or the calculated rotation amount. apparatus. The controller is
Each time the stepping motor is driven by n (where n ≧ 1) steps, the amount of rotation obtained by the product of the first amount of rotation and n as the amount of rotation of the rotating body by the encoder, or the obtained amount 5. The printing apparatus according to claim 3, wherein a step-out of the stepping motor is detected by determining whether or not a rotation amount that reflects a margin in the rotation amount is detected. The controller is
Each time the stepping motor is driven by n (where n ≧ 1) steps, k is the amount by which the stepping motor is driven by the encoder as the cumulative amount of rotation of the rotating body during the predetermined period. > N) It is determined whether or not a rotation amount obtained by the product of the number of steps and the first rotation amount or a rotation amount reflecting a margin in the obtained rotation amount is detected, and the stepping motor The printing apparatus according to claim 6, wherein step-out is detected. The controller is
When the stepping motor is driven by k (where k> n) steps, the rotation amount obtained by the product of the first rotation amount and k as the rotation amount of the rotating body by the encoder, or the determination The printing apparatus according to claim 6, wherein a step-out of the stepping motor is detected by determining whether or not a rotation amount that reflects a margin is detected in the rotation amount. The controller is
In the first predetermined period after the start of the driving of the stepping motor and in the second predetermined period before the end of the driving of the stepping motor, step-out of the stepping motor is not detected. A printing apparatus according to any one of claims 1 to 6. The print head is composed of a line inkjet head,
The controller is
8. The carriage according to claim 1, wherein the carriage on which the print head is mounted is moved from a home position to a print position or from the print position to the home position by driving the stepping motor. A printing apparatus according to 1.   For a printing apparatus including a stepping motor, a carriage on which a print head is mounted, and moving according to the driving of the stepping motor, and an encoder that detects the amount of movement of the carriage, the control unit controls the stepping motor. A movement amount of the carriage detected by the encoder when driven by a predetermined amount, and a predicted movement amount of the carriage predicted when the stepping motor is driven by the predetermined amount without being stepped out. A step-out detection method comprising detecting step-out of the stepping motor based on the comparison.

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