Printer and control method

Abstract

To provide a printer and a control method capable of quickly printing even when producing high-quality printed matter. [Solution] The printer includes a thermal head, a platen roller, a motor, and a CPU. The thermal head prints on a medium. The platen roller transports the medium toward the thermal head. The motor drives the platen roller by rotating. The CPU switches the motor control mode between a first mode and a second mode. The acceleration / deceleration time in the second mode is longer than the acceleration / deceleration time in the first mode. The amount of jerk change in the second mode is smaller than the amount of jerk change in the first mode.

Description

[Technical Field]

[0001] The present invention relates to a printer and a control method. [Background technology]

[0002] The printing device described in Patent Document 1 has a platen roller and a thermal head. The platen roller is rotated by a stepping motor and transports the roll sheet. The thermal head has heating elements arranged in a row. The thermal head divides the heating elements into multiple blocks, and each block is powered separately to print on the roll sheet. When printing on the roll sheet, the printing device reads ahead any print line from the print data. Based on the read-ahead print lines, the printing device counts the number of heating elements that will print on each print line. Based on the counted number of heating elements, the printing device determines the number of divisions of the heating elements. Based on the determined number of divisions, the printing device determines the printing speed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-280221 Summary of the Invention [Problem to be solved by the invention]

[0004] The quality of printed material varies depending on the magnitude of the time derivative (jerk) of the acceleration of the stepping motor that transports the roll sheet to the thermal head. When producing high-quality prints, the printing device can maximize the number of divisions and fix the printing speed at the slowest possible speed to eliminate jerk variations. However, fixing the printing speed at the slowest possible speed slows down the production of printed material.

[0005] SUMMARY OF THE INVENTION An object of the present invention is to provide a printer and a control method that can print quickly even when producing high-quality printed matter. [Means for solving the problem]

[0006] A printer according to a first aspect of the present invention comprises a printing unit that prints on a medium, a transport unit that transports the medium toward the printing unit, a motor that drives the transport unit by rotation, and a control unit, wherein the control unit controls the motor by switching between a first mode that controls the rotation of the motor and a second mode that is different from the first mode, in which the length of the acceleration / deceleration time required to change the motor from a starting speed to a target speed is longer than the length of the acceleration / deceleration time in the first mode, and the amount of jerk change when changing the motor from the starting speed to the target speed is smaller than the amount of jerk change in the first mode.

[0007] According to a first aspect, the printer switches motor control between a first mode for producing normal-quality printouts and a second mode for producing high-quality printouts. In the second mode, the motor is changed from a starting speed to a target speed. The acceleration / deceleration time in the second mode is longer than that in the first mode, and the amount of jerk change in the second mode is smaller than that in the first mode. Therefore, in the second mode, sudden changes in motor speed and acceleration are eliminated even when the motor speed is changed, allowing the printer to ensure the quality of the printouts. This allows the printer to print quickly even when producing high-quality printouts.

[0008] In the first aspect, the acceleration / deceleration time in the second mode may be shorter than the deceleration time required to accelerate from the first speed (the starting speed) to the second speed (the target speed), which is faster than the first speed. This allows the motor in the printing device to accelerate from the first speed to the second speed in a short time, since the acceleration time required to accelerate from the first speed to the second speed is shorter than the deceleration time required to decelerate from the second speed to the first speed. This allows the printing device to print more quickly, even when producing high-quality printed materials.

[0009] In the first aspect, when accelerating in the second mode from the start speed, which is faster than the fastest printing speed based on the printing cycle of the printing unit, to a third speed that is the target speed and is faster than the fastest printing speed, the control unit may control the motor based on the second mode from the start speed to the fastest printing speed, and then control the motor based on the second mode from the fastest printing speed to the third speed. According to this, when accelerating the motor to the third speed, which is faster than the fastest printing speed, the printer does not accelerate from the start speed to the third speed in one go, but rather accelerates from the start speed to the fastest printing speed in the second mode, and then accelerates from the fastest printing speed to the third speed. The printer prints using the printing unit while transporting the medium using the transport unit, and can transport the medium stably even when transporting the medium at a speed faster than the fastest printing speed.

[0010] In the first aspect, the printing unit is a thermal head having a plurality of heating elements arranged and divisible into a plurality of blocks, with each block being supplied with power to perform printing, and the control unit may change the motor speed in the second mode depending on the number of blocks to which power is supplied to the thermal head. In this way, the printer changes the motor speed depending on the number of blocks into which the heating elements are divided, so that the thermal head prints in synchronization with the medium being transported, thereby ensuring the quality of the printed matter.

[0011] A control method according to a second aspect of the present invention is a control method for a printer including a printing unit that prints on a medium, a transport unit that transports the medium toward the printing unit, and a motor that drives the transport unit by rotation, wherein the control method switches between a first mode that controls the rotation of the motor and a second mode that is different from the first mode, in which the length of the acceleration / deceleration time required to change the motor from a starting speed to a target speed is longer than the acceleration / deceleration time in the first mode and the amount of change in jerk when changing the motor from the starting speed to the target speed is smaller than the amount of change in jerk in the first mode. The second aspect achieves the same effects as the first aspect. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a perspective view of a printer 1. [Figure 2] 2 is a cross-sectional view of the printer 1 taken along a plane perpendicular to the left-right direction. [Figure 3] 2 is a block diagram showing the electrical configuration of the printer 1. FIG. [Figure 4] 10A and 10B are diagrams showing the change in speed over time in the first mode and the second mode when the motor 24 accelerates from a speed V0 to a target speed and when the motor 24 decelerates from a starting speed to a speed V0. [Figure 5] 10A and 10B are diagrams showing the change in speed over time in the first mode and the second mode when the motor 24 accelerates from a speed V1 to a target speed and when the motor 24 decelerates from a starting speed to the speed V1. [Figure 6] 10A and 10B are diagrams showing the change in speed over time in the first mode and the second mode when the motor 24 accelerates from a speed V2 to a target speed and when the motor 24 decelerates from a starting speed to a speed V2. [Figure 7] 10A and 10B are diagrams showing the change in speed over time in the first mode and the second mode when the motor 24 accelerates from speed V3 to speed V4 and when the motor 24 decelerates from speed V4 to speed V3. [Figure 8] 10A and 10B are diagrams showing the time changes in speed, acceleration, and jerk in the first and second modes when the motor 24 accelerates from speed V0 to speed V3. [Figure 9] 10A and 10B are diagrams showing the time changes in speed, acceleration, and jerk in the first and second modes when the motor 24 decelerates from speed V3 to speed V0. [Figure 10] 10A and 10B are diagrams showing the time changes in speed, acceleration, and jerk in the first and second modes when the motor 24 accelerates from speed V0 to speed V4. [Figure 11]FIG. 10 is a conceptual diagram showing an acceleration table 62A. [Figure 12] FIG. 10 is a conceptual diagram showing a deceleration table 72A. [Figure 13] FIG. 10 is a conceptual diagram showing an acceleration table 63A. [Figure 14] FIG. 10 is a conceptual diagram showing an acceleration table 62B. [Figure 15] FIG. 10 is a conceptual diagram showing a deceleration table 72B. [Figure 16] FIG. 10 is a conceptual diagram showing an acceleration table 63B. [Figure 17] 10 is a flowchart of a main process. DETAILED DESCRIPTION OF THE INVENTION

[0013] An embodiment of the present invention will be described below with reference to the drawings. The drawings are used to explain technical features that may be employed by the present invention. The device configurations shown in the drawings are merely illustrative examples and are not intended to be limiting. Hereinafter, the upper left, lower right, lower left, upper right, lower, and upper in FIG. 1 will be referred to as the left, right, front, rear, lower, and upper of the printer 1, respectively.

[0014] The configuration of a printer 1 will be described with reference to Figure 1. The printer 1 is a thermal printer that prints on a medium 10 using a thermal head 31 shown in Figure 2. The medium 10 is a strip of thermal paper.

[0015] The printer 1 has a housing 2 and a cover 5. The housing 2 is box-shaped and is deeper than it is wide. The cover 5 is located at the rear of the top surface of the housing 2. A support shaft (not shown) is engaged with the cover 5. The support shaft extends left and right from the rear end of the cover 5 and is supported by the rear end of the housing 2. The cover 5 can be opened and closed freely, with the support shaft as the center of rotation.

[0016] The housing 2 is provided with an operation unit 7, a tray 6, a mounting unit 4, and a lever 11. The operation unit 7 is located at the front end of the top surface of the housing 2 and includes various input buttons. The various input buttons are, for example, a FEED key and a power key. The tray 6 is located behind the operation unit 7 and extends upward from the top surface of the housing 2. When the cover 5 is closed, an ejection port 21 is formed between the front end of the cover 5 and the tray 6.

[0017] The mounting section 4 is disposed at the rear end of the housing 2. When the cover 5 is closed, the mounting section 4 is covered from above by the cover 5. The mounting section 4 includes a storage section 42, a right support section 41, and a left support section (not shown). The storage section 42 is an arc-shaped plate that is concave downward in a side view. The right support section 41 is disposed at the right end of the storage section 42. The left support section is disposed at the left end of the storage section 42.

[0018] With the cover 5 open, the mounting section 4 can mount the holder 3. The holder 3 has a spool 35. The medium 10 is wound around the spool 35. The holder 3 is stored in the storage section 42 with the axis of the spool 35 extending in the left-right direction, and is clamped between the right support section 41 and the left support section. In this way, the holder 3 is mounted in the mounting section 4.

[0019] The lever 11 is disposed at the left end of the housing 2, between the tray 6 and the mounting portion 4 in the front-to-rear direction. When the cover 5 is open, the lever 11 extends in the vertical direction. The upper end of the lever 11 is located above the top surface of the housing 2. The lower end of the lever 11 is stored in the housing 2. The lever 11 can swing in the front-to-rear direction around the lower end of the lever 11. The lower end of the lever 11 is connected to a roller holder 25, which will be described later.

[0020] The internal configuration of the printer 1 will be described with reference to Figure 2. The housing 2 houses a roller holder 25, a platen roller 26, a transport roller 28, a connection roller 27, and a thermal head 31. The roller holder 25 is located in front of the mounting portion 4 and to the right of the lever 11. The roller holder 25 is box-shaped and is wider than it is deep.

[0021] The roller holder 25 moves up and down in response to the swinging of the lever 11. When the cover 5 is open and the lever 11 extends up and down, the roller holder 25 is located at the upper end of its range of movement in the up and down direction. When the cover 5 is closed, the upper end of the lever 11 swings backward. When the cover 5 is closed, the roller holder 25 is located at the lower end of its range of movement in the up and down direction.

[0022] The roller holder 25 supports a platen roller 26, a transport roller 28, and a connecting roller 27. The platen roller 26 is disposed at the lower front end of the roller holder 25. The lower end of the platen roller 26 is located lower than the lower end of the roller holder 25. The platen roller 26 has an axis that extends in the left-right direction.

[0023] The platen roller 26 is connected to the rotation shaft of a motor 24 shown in Fig. 3. The motor 24 is, for example, a stepping motor. When the motor 24 rotates, the platen roller 26 rotates around its axis.

[0024] The transport roller 28 is spaced rearward from the platen roller 26. The lower end of the transport roller 28 is positioned lower than the lower end of the roller holder 25. The transport roller 28 has a shaft center that extends in the left-right direction. The transport roller 28 can rotate around the shaft center.

[0025] The connecting roller 27 is disposed behind the platen roller 26 and above the transport roller 28. The connecting roller 27 contacts the side surface of the platen roller 26 and the side surface of the transport roller 28. The connecting roller 27 has an axis extending in the left-right direction. The connecting roller 27 can rotate around the axis. The connecting roller 27 rotates with the rotation of the platen roller 26, and the transport roller 28 rotates with the rotation of the connecting roller 27.

[0026] When the motor 24 rotates, the platen roller 26 and the transport roller 28 rotate clockwise as viewed from the right side. The medium 10 is fed from the holder 3 shown in FIG. 1, contacts the lower ends of the platen roller 26 and the transport roller 28, and is transported forward along the transport path 22.

[0027] The thermal head 31 is disposed below the platen roller 26 and the transport roller 28. That is, the thermal head 31 is disposed below the platen roller 26 and the transport roller 28 with the transport path 22 between them. The thermal head 31 includes a substrate 32 and a plurality of heating elements (not shown). The substrate 32 is plate-shaped and is wider than it is deep. The plurality of heating elements are disposed on the upper surface of the substrate 32 and are aligned in the left-right direction.

[0028] When the roller holder 25 is located at the upper end of its vertical movement range, the platen roller 26 and the transport roller 28 are spaced upward from the thermal head 31. When the roller holder 25 is located at the lower end of its vertical movement range, the platen roller 26 and the transport roller 28 press the medium 10 downward toward the thermal head 31.

[0029] With the medium 10 sandwiched between the platen roller 26, the transport roller 28, and the thermal head 31, the printer 1 rotates the motor 24 and causes the multiple heating elements to heat. In this way, the printer 1 prints on the medium 10. The medium on which printing has been completed is called a printed matter. The printed matter is discharged from the housing 2 through the discharge port 21. The tray 6 receives the discharged printed matter.

[0030] The electrical configuration of the printer 1 will be described with reference to Figure 3. The printer 1 has a CPU 91, a ROM 92, a RAM 93, a storage device 94, an interface 95, and drivers 81 and 82. The CPU 91 controls the printer 1 and functions as a control unit. The CPU 91 is electrically connected to the RAM 93, the ROM 92, the storage device 94, the interface 95, and the operation unit 7.

[0031] The RAM 93 temporarily stores various information necessary for the CPU 91 to execute processing. The RAM 93 includes a print buffer 43 and a division number memory 44. The print buffer 43 is a storage area for storing print data received from an external terminal 99. The external terminal 99 is, for example, a personal computer, a smartphone, etc. The division number memory 44 is a storage area for storing the division number, which will be described later.

[0032] 17, and various setting information. The storage device 94 is nonvolatile and stores acceleration tables 60A-69A, 60B-69B, and deceleration tables 70A-79A, and 70B-79B, which will be described later. The CPU 91 outputs a control signal to the driver 81 based on the acceleration tables 60A-69A, 60B-69B, or the deceleration tables 70A-79A, 70B-79B, as will be described later in detail.

[0033] The interface 95 is connected to the driver 81 and the driver 82. The interface 95 can be connected to an external terminal 99 via a cable 98. The cable 98 is a cable that enables the printer 1 to communicate with the external terminal 99, and is, for example, a USB (Universal Serial Bus) cable. The driver 81 rotates the carry motor 16 based on a control signal received from the CPU 91.

[0034] The driver 82 causes the multiple heating elements of the thermal head 31 to heat up based on the strobe signal received from the CPU 91. When the thermal head 31 receives the strobe signal, the multiple heating elements heat up. When the thermal head 31 does not receive the strobe signal, the multiple heating elements do not heat up. In other words, in the printer 1, the interval at which the CPU 91 sends the strobe signal is the printing cycle. In Figures 8 and 9, when the CPU 91 is sending the strobe signal, it is indicated by "ON," and when the CPU 91 is not sending the strobe signal, it is indicated by "OFF."

[0035] The print data in this embodiment is composed of a plurality of print lines. Each print line is print data printed by the thermal head 31 in one printing operation. The pre-reading program 51 is a program that pre-reads the print data stored in the print buffer 40.

[0036] When the printer 1 performs printing on the medium 10, first, the CPU 91 executes the pre-reading program 51 stored in the ROM 92. As a result, the CPU 91 pre-reads the print data stored in the print buffer 43 of the RAM 93. The CPU 91 counts the number of heating elements that generate heat in each print line from the pre-read print data.

[0037] Based on the counted number of heating elements, the CPU 91 determines the number of divisions of the heating elements in each print line. In the printer 1 of this embodiment, the thermal head 31 can divide a plurality of heating elements into blocks from 1 to 3. The thermal head 31 is supplied with power for each block to perform printing. In this embodiment, the number of blocks of the heating elements to be supplied with power is equal to the number of divisions of the heating elements determined by the CPU 91.

[0038] As shown in FIGS. 4 to 7, the motor 24 can be shifted in five steps of speeds 0, V1, V2, V3, and V4. At speed 0, the rotation of the motor 24 is stopped. Speed V1 is faster than speed 0, speed V2 is faster than speed V1, speed V3 is faster than speed V2, and speed V4 is faster than speed V3 (0 < V1 < V2 < V3 < V4). Also in this embodiment, speed V4 is equal to the sum of speed V3 and speed V1 (V4 = V3 + V1).

[0039] The CPU 91 determines the speed of the motor 24 according to the number of blocks for supplying power to the thermal head 31. More specifically, the CPU 91 determines the speed of the motor 24 according to the maximum value of the number of blocks in the print lines for 24 lines. Here, 24 lines are print lines that are twice the number of 12 lines of print lines that can be printed in the time required to decelerate from speed V4 to speed 0 in the second mode described later.

[0040] In the printer 1, the transport by the platen roller 26 and the printing by the thermal head 31 are synchronized. The printing cycle of the thermal head 31 is determined based on the interval at which the CPU 91 outputs a strobe signal. When the interval at which the strobe signal is output is the shortest, the printing cycle of the thermal head 31 becomes the smallest minimum printing cycle. Speed ​​V3 is the speed of the motor 24 that synchronizes with the minimum printing cycle. Hereinafter, speed V3 will also be referred to as the fastest printing speed.

[0041] In printer 1, the smaller the maximum number of blocks in a 24-line print line, the faster CPU 91 increases the speed of motor 24. More specifically, when the maximum number of blocks in a 24-line print line is 3, CPU 91 sets motor 24 to speed V1. When the maximum number of blocks in a 24-line print line is 2, CPU 91 sets motor 24 to speed V2. When the maximum number of blocks in a 24-line print line is 1, CPU 91 sets motor 24 to speed V3. When the maximum number of blocks in a 24-line print line is 0, CPU 91 sets motor 24 to speed V4.

[0042] The CPU 91 determines the speed of the motor 24 when printing the next 12 print lines from the maximum number of blocks in the next 24 print lines. For example, if the speed of the rotating motor 24 is speed V1 and the maximum number of blocks in the next 24 print lines is 1, the CPU 91 accelerates the speed of the motor 24 from speed V1 to speed V3. Hereinafter, the speed of the motor 24 before acceleration / deceleration is referred to as the start speed, and the speed of the motor 24 after acceleration / deceleration is referred to as the target speed.

[0043] The printer 1 has a first mode and a second mode set as control modes for the rotation of the motor 24. The first mode is a control mode for producing printed matter of normal quality, and the second mode is a control mode for producing printed matter of high quality. The first mode and the second mode differ in the control for accelerating / decelerating the motor 24 from the starting speed to the target speed.

[0044] As shown in FIGS. 4 to 9, in the first mode, the CPU 91 accelerates / decelerates the speed of the motor 24 in proportion to time. Referring to FIG. 8, the control of the first mode when the CPU 91 accelerates the motor 24 will be described. In FIG. 8, the starting speed is speed 0 and the target speed is speed V3.

[0045] The CPU 91 starts to accelerate the motor 24 at time 0. At time 0, the speed of the motor 24 is 0 and the acceleration of the motor 24 is 0. In the first mode, the CPU 91 accelerates the motor 24 at a constant acceleration AA03 (0 < AA03) from speed 0 to speed V3. The acceleration of the motor 24 continuously changes from acceleration 0 to acceleration AA03 during a very short time.

[0046] The jerk of the motor 24 becomes JA03 (0 < JA03) at time 0. The jerk is the time derivative of the acceleration. Since the acceleration of the motor 24 changes from acceleration 0 to acceleration AA03 during a very short time, the magnitude of the jerk JA03 is extremely large. The magnitude of the jerk JA03 is larger than the jerk threshold JT described later (0 < JT < JA03). When a very short time elapses from time 0, the acceleration of the motor 24 becomes constant at acceleration AA03 and the jerk of the motor 24 becomes 0.

[0047] The speed of the motor 24 accelerates at a constant acceleration AA03 and reaches speed V3 when a time TA03 (0 < TA03) elapses from time 0. Between time 0 and time TA03, the CPU 91 outputs a strobe signal based on the printing cycle. During the period from time 0 to time TA03, the thermal head 31 prints 12 lines of printing lines.

[0048] The speed of the motor 24 reaches speed V3 at time TA03, and then remains constant at speed V3. Until an infinitesimal amount of time has elapsed from time TA03, the acceleration of the motor 24 changes continuously from acceleration AA03 to acceleration 0. The jerk of the motor 24 changes from jerk 0 to jerk -JA03 at time TA03. After an infinitesimal amount of time has elapsed from time TA03, the jerk of the motor 24 changes from jerk -JA03 to jerk 0, and then remains constant at jerk 0.

[0049] When the CPU 91 accelerates the motor 24 from speed 0 to speed V3, the change in jerk of the motor 24 is twice the jerk JA03 (2JA03). Note that the change in jerk in the printer 1 is the difference obtained by subtracting the minimum jerk from the maximum jerk when changing from the starting speed to the target speed.

[0050] In the first mode, the CPU 91 accelerates the motor 24 based on acceleration tables 60A-69A shown in Fig. 3. The acceleration tables 60A-69A each set a conveyance period, acceleration time, and acceleration for 12 lines when accelerating from a start speed to a target speed. For example, the acceleration table 62A shown in Fig. 11 sets a print period, acceleration time, and acceleration for 12 lines when accelerating from speed 0 to speed V3.

[0051] The transport period is the time required for the motor 24 to transport the medium 10 by one line. In this embodiment, the transport period of the motor 24 is equal to the printing period of the thermal head 31. The acceleration time is the time required for the motor 24 to accelerate from the starting speed to the target speed.

[0052] When accelerating the motor 24 from speed 0 to speed V1 in the first mode, the CPU 91 refers to acceleration table 60A. When accelerating the motor 24 from speed 0 to speed V2 in the first mode, the CPU 91 refers to acceleration table 61A. When accelerating the motor 24 from speed 0 to speed V3 in the first mode, the CPU 91 refers to acceleration table 62A shown in FIG. 11. When accelerating the motor 24 from speed 0 to speed V4 in the first mode, the CPU 91 refers to acceleration table 63A shown in FIG.

[0053] The CPU 91 refers to acceleration table 64A when accelerating motor 24 from speed V1 to speed V2 in the first mode. The CPU 91 refers to acceleration table 65A when accelerating motor 24 from speed V1 to speed V3 in the first mode. The CPU 91 refers to acceleration table 66A when accelerating motor 24 from speed V1 to speed V4 in the first mode.

[0054] The CPU 91 refers to acceleration table 67A when accelerating motor 24 from speed V2 to speed V3 in the first mode. The CPU 91 refers to acceleration table 68A when accelerating motor 24 from speed V2 to speed V4 in the first mode. The CPU 91 refers to acceleration table 69A when accelerating motor 24 from speed V3 to speed V4 in the first mode.

[0055] Referring to Figure 9, the control of the first mode when the CPU 91 decelerates the motor 24 will be described. In Figure 9, the starting speed is speed V3 and the target speed is speed V0. The CPU 91 starts decelerating the motor 24 at time 0. At time 0, the speed of the motor 24 is V3 and the acceleration of the motor 24 is 0.

[0056] The CPU 91 decelerates the motor 24 from speed V3 to speed 0 at a constant acceleration -AA30 (-AA30<0). In the first mode, when decelerating from one speed to another, the CPU 91 performs control in which the positive and negative values ​​are reversed relative to the control of accelerating from the other speed to one speed. That is, in the first mode, the acceleration AA30 when the CPU 91 decelerates from speed V3 to speed 0 is equal in magnitude to the acceleration AA03 when the CPU 91 accelerates from speed 0 to speed V3, as shown in FIG. 8.

[0057] The jerk of the motor 24 is −JA30 (−JA30=−JA03) at time 0. When a small amount of time has passed from time 0, the acceleration of the motor 24 becomes constant at acceleration −AA30, and the jerk of the motor 24 becomes zero.

[0058] The speed of the motor 24 becomes 0 at time TA30. In the first mode, the time TA30 required to decelerate from speed V3 to speed 0 is the same as the time TA03 required to accelerate from speed 0 to speed V3. Between time 0 and time TA30, the CPU 91 outputs a strobe signal based on the printing cycle. Between time 0 and time TA30, the thermal head 31 prints 12 print lines.

[0059] The speed of the motor 24 reaches 0 at time TA30 and then remains constant at 0. The acceleration of the motor 24 changes continuously from acceleration -AA30 to acceleration 0 at time TA30. The jerk of the motor 24 changes from jerk 0 to jerk JA30 at time TA30.

[0060] After a short time has passed from time TA30, the jerk of motor 24 changes from jerk -JA03 to jerk 0, and then remains constant at jerk 0. When the speed of motor 24 decelerates from speed V3 to speed 0, the amount of change in the jerk of motor 24 is twice the jerk JA30 (2JA30).

[0061] In the first mode, the CPU 91 decelerates the motor 24 based on the deceleration tables 70A to 79A shown in FIG. 3. The deceleration tables 70A to 79A each set a print cycle, acceleration time, and acceleration for 12 lines when decelerating from the starting speed to the target speed. For example, the deceleration table 72A shown in FIG. 12 sets a print cycle, deceleration time, and acceleration for 12 lines when decelerating from speed V3 to speed 0. The deceleration time is the time required to decelerate the motor 24 from the starting speed to the target speed. The acceleration time and deceleration time are collectively referred to as acceleration / deceleration time.

[0062] The CPU 91 refers to deceleration table 70A when decelerating the motor 24 from speed V1 to speed 0 in the first mode. The CPU 91 refers to deceleration table 71A when decelerating the motor 24 from speed V2 to speed 0 in the first mode. The CPU 91 refers to deceleration table 72A shown in Fig. 12 when decelerating the motor 24 from speed V3 to speed 0 in the first mode. The CPU 91 refers to deceleration table 73A when decelerating the motor 24 from speed V4 to speed 0 in the first mode.

[0063] The CPU 91 refers to deceleration table 74A when decelerating motor 24 from speed V2 to speed V1 in the first mode. The CPU 91 refers to deceleration table 75A when decelerating motor 24 from speed V3 to speed V1 in the first mode. The CPU 91 refers to deceleration table 76A when decelerating motor 24 from speed V4 to speed V1 in the first mode.

[0064] The CPU 91 refers to deceleration table 77A when decelerating the motor 24 from speed V3 to speed V2 in the first mode. The CPU 91 refers to deceleration table 78A when decelerating the motor 24 from speed V4 to speed V2 in the first mode. The CPU 91 refers to deceleration table 79A when decelerating the motor 24 from speed V4 to speed V3 in the first mode.

[0065] In the first mode, when the speed of the motor 24 changes, the motor 24 accelerates / decelerates at a constant acceleration. Since the acceleration of the motor 24 changes from an acceleration of 0 to a constant acceleration in a very short time, the change amount of the jerk of the motor 24 becomes very large. For example, the change amounts of the jerk 2JA03 and 2JA30 of the motor 24 are larger than twice the jerk threshold JT (2JT < 2JA03 = 2JA30). Since the change amount of the jerk is the change amount of the inertial force applied to the medium 10, the change amount of the jerk contributes to the quality of the printed matter. When a high-quality printed matter is produced, it is preferable that the change amount of the jerk is small.

[0066] Referring to FIGS. 8 and 9, the control of the second mode will be described. First, referring to FIG. 8, the control of the second mode when the CPU 91 accelerates the motor 24 will be described. In FIG. 8, the starting speed is speed 0 and the target speed is speed V3. At time 0, the speed of the motor 24 is 0 and the acceleration of the motor 24 is 0. The CPU 91 starts to accelerate the motor 24 at time 0.

[0067] As shown in FIG. 8, in the second mode, the acceleration time when accelerating from speed 0 to speed V3 is time TB03 (0 < TB03). The acceleration time TB03 in the second mode is longer than the acceleration time TA03 in the first mode and the deceleration time TA30 in the first mode.

[0068] Furthermore, the magnitude of the jerk when the motor 24 accelerates / decelerates in the second mode is smaller than the absolute value of the jerk threshold JT. That is, the change amount of the jerk of the motor 24 in the second mode is smaller than twice the jerk threshold JT. More specifically, when accelerating from speed 0 to speed V3 in the second mode, from time 0 to time TB03 / 2, the magnitude of the jerk is constant at jerk JB03 (0 < JB03). From time TB03 / 2 to time TB03, the magnitude of the jerk is constant at jerk -JB03. Note that time TB03 / 2 is half of time TB03.

[0069] The change amount of the jerk of the motor 24 is twice that of the jerk JB03 (2JB03) and smaller than twice the jerk threshold JT (2JB03 < 2JT). That is, the change amount of the jerk of the motor 24 in the second mode is smaller than the change amount of the jerk in the first mode (2JB03 < 2JT < 2JA03 = 2JA30).

[0070] In the second mode, from time 0 to time TB03 / 2, the magnitude of the jerk is constant at jerk JB03, and the acceleration of the motor 24 increases proportionally with time. From time TB03 / 2 to time TB03, the magnitude of the jerk is constant at jerk - JB03, and the acceleration of the motor 24 decreases proportionally with time. That is, the acceleration of the motor 24 from time 0 to time TB03 has a convex - upward shape and has a mountain - type time - change with the acceleration AB03 (0 < AB03) being the extreme value at time TB03 / 2.

[0071] Since the acceleration time of the second mode is longer than the acceleration time and the deceleration time of the first mode, the motor 24 accelerates gently in the second mode. In addition, the change amount of the jerk of the motor 24 in the second mode is smaller than the change amount of the jerk in the first mode. Therefore, the printer 1 in the second mode can produce high - quality printed matter while accelerating the motor 24.

[0072] As shown in FIG. 10, when the control mode is the second mode and the target speed is the speed V4, the CPU 91 accelerates the motor 24 in the second mode from the start speed to the speed V3 and then accelerates the motor 24 in the second mode from the speed V3 to the speed V4. The speed V3 is the fastest printing speed based on the printing cycle of the thermal head 31.

[0073] For example, when the CPU 91 accelerates the motor 24 from speed 0 to speed V4 in the second mode, after accelerating the motor 24 in the second mode from speed 0 to speed V3, the motor 24 is accelerated from speed V3 to speed V4 in the second mode. The acceleration time from speed 0 to speed V4 is time TB04. The time TB04 is longer than the time TA04, which is the acceleration time from speed 0 to speed V4 in the first mode (TA04 < TB04). The time TB04 is equal to the sum of the time TB03, which is the acceleration time from speed 0 to speed V3 in the second mode, and the time TB01, which is the acceleration time from speed 0 to speed V1 in the second mode (TB04 = TB03 + TB01).

[0074] When accelerating from speed 0 to speed V4 in the second mode, from time 0 to time TB03 / 2, the magnitude of the jerk is constant at jerk JB03 (0 < JB03 < JT). From time TB03 / 2 to time TB03, the magnitude of the jerk is constant at jerk -JB03.

[0075] From time TB03 to time TB03+(TB01 / 2), the magnitude of the jerk is constant at jerk JB01. Note that the time TB01 / 2 is half of the time TB01. The time TB01 is the acceleration time from speed 0 to speed V1. The jerk JB01 is the maximum value of the jerk of the motor 24 when the CPU 91 accelerates the motor 24 from speed 0 to speed V1 in the second mode.

[0076] The jerk JB01 is smaller than the jerk threshold JT (0 < JB01 < JT). In this embodiment, the jerk JB01 is larger than the jerk JB03 (JB03 < JB01), but the jerk JB01 may be equal to the jerk JB03. The jerk JB01 may be smaller than the jerk JB03.

[0077] From time TB03+(TB01 / 2) to time TB04, the magnitude of the jerk is constant at jerk -JB03. The change amount of the jerk of the motor 24 is twice the jerk JB01 (2JB01), and is smaller than twice the jerk threshold JT (2JB01 < 2JT).

[0078] From time 0 to time TB03 / 2, the acceleration of the motor 24 increases proportionally with time. From time TB03 / 2 to time TB03, the acceleration of the motor 24 decreases proportionally with time. From time TB03 to time TB03+(TB01 / 2), the acceleration of the motor 24 increases proportionally with time. From time TB03+(TB01 / 2) to time TB04, the acceleration of the motor 24 decreases proportionally with time. That is, the time change of the acceleration of the motor 24 from time 0 to time TB04 has two peaks, a first peak with acceleration AB03 at time TB03 / 2 and a second peak with acceleration AB01 (0 < AB01) at time TB03+(TB01 / 2).

[0079] As shown in FIGS. 5 and 6, when accelerating from speed V1 to speed V4 in the second mode or when accelerating from speed V2 to speed V4 in the second mode, the CPU 91 performs the same control as when accelerating from speed V0 to speed V4 in the second mode. That is, when accelerating from speed V1 to speed V4 in the second mode, the CPU 91 accelerates from speed V1 to speed V3 in the second mode and then accelerates from speed V3 to speed V4 in the second mode. When the CPU 91 accelerates from speed V1 to speed V4 in the second mode, it accelerates from speed V1 to speed V3 in the second mode and then accelerates from speed V3 to speed V4 in the second mode.

[0080] In the second mode, the CPU 91 accelerates the motor 24 based on the acceleration tables 60B to 69B shown in FIG. 3. In the acceleration tables 60B to 62B, 64B, 65B, 67B, and 69B, the conveyance periods, acceleration times, maximum accelerations, and maximum jerks for 12 lines when accelerating from the start speed to the target speed are set respectively. The maximum acceleration is the maximum value of the acceleration of the motor 24 when accelerating from the start speed to the target speed. The maximum jerk is the maximum value of the jerk of the motor 24 when accelerating from the start speed to the target speed. For example, in the acceleration table 62B shown in FIG. 14, the print periods, acceleration times, and accelerations for 12 lines when accelerating from speed 0 to speed V3 are set respectively.

[0081] The acceleration tables 63B, 66B, and 68B respectively set a conveyance period for 12 lines, a first acceleration time, a first maximum acceleration, a first maximum jerk, a second acceleration time, a second maximum acceleration, and a second maximum jerk when accelerating from the start speed to speed V4. The first acceleration time is the acceleration time when accelerating from the start speed to speed V3. The first maximum acceleration is the maximum value of the acceleration of the motor 24 when accelerating from the start speed to speed V3. The first maximum jerk is the maximum value of the jerk of the motor 24 when accelerating from the start speed to speed V3.

[0082] The second acceleration time is the acceleration time when accelerating from speed V3 to speed V4. The second maximum acceleration is the maximum acceleration value of the motor 24 when accelerating from speed V3 to speed V4. The second maximum jerk is the maximum jerk value of the motor 24 when accelerating from speed V3 to speed V4. For example, the acceleration table 63B shown in FIG. 16 has set therein the conveyance period for 12 lines, the first acceleration time, the first maximum acceleration, the first maximum jerk, the second acceleration time, the second maximum acceleration, and the second maximum jerk when accelerating from speed 0 to speed V4.

[0083] When accelerating the motor 24 from speed 0 to speed V1 in the second mode, the CPU 91 refers to acceleration table 60B. When accelerating the motor 24 from speed 0 to speed V2 in the second mode, the CPU 91 refers to acceleration table 61B. When accelerating the motor 24 from speed 0 to speed V3 in the second mode, the CPU 91 refers to acceleration table 62B shown in FIG. 14. When accelerating the motor 24 from speed 0 to speed V4 in the second mode, the CPU 91 refers to acceleration table 63B shown in FIG.

[0084] When accelerating the motor 24 from speed V1 to speed V2 in the second mode, the CPU 91 refers to acceleration table 64B. When accelerating the motor 24 from speed V1 to speed V3 in the second mode, the CPU 91 refers to acceleration table 65B. When accelerating the motor 24 from speed V1 to speed V4 in the second mode, the CPU 91 refers to acceleration table 66B.

[0085] When the CPU 91 accelerates the motor 24 from speed V2 to speed V3 in the second mode, it refers to the acceleration table 67B. When the CPU 91 accelerates the motor 24 from speed V2 to speed V4 in the second mode, it refers to the acceleration table 68B. When the CPU 91 accelerates the motor 24 from speed V3 to speed V4 in the second mode, it refers to the acceleration table 69B.

[0086] Referring to FIG. 9, the control of the second mode when the CPU 91 decelerates the motor 24 will be described. In FIG. 9, the starting speed is speed V3 and the target speed is speed V0. The CPU 91 starts to decelerate the motor 24 at time 0. At time 0, the speed of the motor 24 is V3 and the acceleration of the motor 24 is 0.

[0087] As shown in FIG. 9, in the second mode, the deceleration time when decelerating from speed V3 to speed 0 is time TB30 (0 < TB30). The deceleration time TB30 in the second mode is longer than the acceleration time TB03 in the second mode (TB03 < TB30). Therefore, the length of time becomes longer in the order of the acceleration time TA03 in the first mode, the deceleration time in the first mode, the acceleration time TB03 in the second mode, and the deceleration time TB30 in the second mode (TA03 = TA30 < TB03 < TB30). In other words, the length of the acceleration and deceleration time in the second mode is longer than the length of the acceleration and deceleration time in the first mode.

[0088] When decelerating from speed V3 to speed 0 in the second mode, from time 0 to time TB30 / 2, the magnitude of the jerk is constant at jerk - JB30 (-JB03 < 0). From time TB30 / 2 to time TB30, the magnitude of the jerk is constant at jerk JB03. Note that time TB30 / 2 is half of time TB30. The magnitude of jerk JB30 is smaller than the magnitude of jerk JB03 (JB30 < JB03).

[0089] The change in jerk of motor 24 is twice the jerk JB30 (2JB30), which is less than twice the jerk threshold JT (2JB30<2JB03<2JT). Therefore, the change in jerk increases in the following order: jerk change 2JB30 when decelerating in the second mode, jerk change 2JB03 when accelerating in the second mode, jerk change 2JA03 when accelerating in the first mode, and jerk change 2JA30 when decelerating in the first mode (2JB30<2JB03<2JA03=2JA30). In other words, the change in jerk in the second mode is smaller than the change in jerk in the first mode.

[0090] In the second mode, from time 0 to time TB30 / 2, the magnitude of the jerk is constant at jerk -JB30, and the acceleration of the motor 24 decreases in proportion to time. From time TB30 / 2 to time TB30, the magnitude of the jerk is constant at jerk JB30, and the acceleration of the motor 24 increases in proportion to time. That is, the acceleration of the motor 24 from time 0 to time TB30 changes in a downward convex shape with a valley-like time variation having an extreme value of acceleration -AB30 (-AB30<0) at time TB30 / 2. The absolute value of acceleration -AB30 when decelerating in the second mode is smaller than the absolute value of acceleration AB03 when accelerating in the second mode (|-AB30|<|AB03|).

[0091] When accelerating to speed V4 in the second mode, the CPU 91 accelerates from the start speed to speed V3 in the second mode, and then accelerates from speed V3 to speed V4 in the second mode. In contrast, when decelerating from speed V4 in the second mode, the CPU 91 does not perform control to decelerate from speed V4 to speed V3 in the second mode, and then decelerate from speed V3 to the target speed in the second mode. When decelerating from speed V4 in the second mode, the CPU 91 decelerates from speed V4 to the target speed in the second mode.

[0092] In the second mode, the CPU 91 decelerates the motor 24 based on the deceleration tables 70B to 79B shown in FIG. 3. The motor 24 is decelerated based on the deceleration tables 70B to 79B. The deceleration tables 70B to 79B each contain a 12-line conveyance period, a deceleration time, a minimum acceleration, and a maximum jerk when decelerating from the starting speed to the target speed. The minimum acceleration is the minimum value of the acceleration of the motor 24 when decelerating from the starting speed to the target speed. For example, the deceleration table 72B shown in FIG. 15 contains a 12-line print period, an acceleration time, and an acceleration when decelerating from speed V3 to speed 0.

[0093] When the CPU 91 decelerates the motor 24 from speed V1 to speed 0 in the second mode, it refers to deceleration table 70B. When the CPU 91 decelerates the motor 24 from speed V2 to speed 0 in the second mode, it refers to deceleration table 71B. When the CPU 91 decelerates the motor 24 from speed V3 to speed 0 in the second mode, it refers to deceleration table 72B shown in Fig. 15. When the CPU 91 decelerates the motor 24 from speed V4 to speed 0 in the second mode, it refers to deceleration table 73B.

[0094] The CPU 91 references deceleration table 74B when decelerating motor 24 from speed V2 to speed V1 in the second mode. The CPU 91 references deceleration table 75B when decelerating motor 24 from speed V3 to speed V1 in the second mode. The CPU 91 references deceleration table 76B when decelerating motor 24 from speed V4 to speed V1 in the second mode.

[0095] The CPU 91 references deceleration table 77B when decelerating motor 24 from speed V3 to speed V2 in the second mode. The CPU 91 references deceleration table 78B when decelerating motor 24 from speed V4 to speed V2 in the second mode. The CPU 91 references deceleration table 79B when decelerating motor 24 from speed V4 to speed V3 in the second mode.

[0096] The main processing executed by the CPU 91 will be described with reference to Fig. 17. When the power key of the operation unit 7 shown in Fig. 1 is operated, the CPU 91 reads the control program 52 for the main processing from the ROM 92. This causes the CPU 91 to start the main processing.

[0097] When the main processing starts, the CPU 91 performs initial settings (S1). In S1, the CPU 91 deletes various information stored in the RAM 93, sets the speed of the motor 24 to speed 0, and sets the control mode of the motor 24 to the first mode. The CPU 91 determines whether or not an instruction to switch the control mode has been received (S2). The user operates the operation unit 7 to input the switching instruction.

[0098] When the CPU 91 determines that a switching instruction has been received (S2: YES), it switches the control mode (S3) and proceeds to S4. In S3, if the current control mode is the first mode, the CPU 91 sets the control mode to the second mode. If the current control mode is the second mode, the CPU 91 sets the control mode to the first mode. When the CPU 91 determines that a switching instruction has not been received (S2: NO), it proceeds to S4.

[0099] The CPU 91 determines whether a print instruction has been received (S4). The print instruction includes print data. The user operates the external terminal 99. The external terminal 99 communicates with the printer 1 based on the user's operation and inputs the print instruction to the CPU 91. When the CPU 91 determines that a print instruction has not been received (S4: NO), the process returns to S2.

[0100] When the CPU 91 determines that a print instruction has been received (S4: YES), it stores the print data included in the print instruction in the print buffer 43 (S6). The CPU 91 then determines the number of blocks for the next 24 print lines to be printed from the print data stored in the print buffer 43 (S7). By determining the number of blocks, the CPU 91 determines the number of divisions of the heating elements and the heating mode of the thermal head 31.

[0101] The CPU 91 determines the next speed of the motor 24 (S8). In S8, the CPU 91 determines the next speed of the motor 24 in accordance with the maximum number of blocks in a print line of 24 lines.

[0102] The CPU 91 determines whether to decelerate the speed of the motor 24 (S9). In S9, the CPU 91 compares the current speed of the motor 24 with the next speed of the motor 24 determined in S8. When the CPU 91 determines that the speed of the motor 24 should be decelerated (S9: YES), the CPU 91 determines one of the deceleration tables 70A-79A and 70B-79B that corresponds to the current control mode of the motor 24, the current speed, and the next speed (S10). The CPU 91 proceeds to S16.

[0103] When the CPU 91 determines that the speed of the motor 24 should not be decreased (S9: NO), it determines whether or not to increase the speed of the motor 24 (S11). In S11, the CPU 91 compares the current speed of the motor 24 with the next speed of the motor 24 determined in S8. When the CPU 91 determines that the speed of the motor 24 should not be increased (S11: NO), it shifts the processing to S16. The speed of the motor 24 is maintained at the current speed of the motor 24.

[0104] When the CPU 91 determines that the speed of the motor 24 is to be accelerated (S11: YES), it determines one of the acceleration tables 60A to 69A, 60B to 76B that corresponds to the current control mode of the motor 24, the current speed, and the next speed (S12).The CPU 91 then proceeds to S16.

[0105] The CPU 91 references the deceleration table determined in S10 or the acceleration table determined in S12 and sets the transport period corresponding to the print line currently being processed (S16). For example, if the control mode is the first mode, deceleration table 72A is determined in S10, and the print line currently being processed is the first line, the CPU 91 sets the transport period to CC201. If the control mode is the second mode, acceleration table 62B is determined in S12, and the print line currently being processed is the third line, the CPU 91 sets the transport period to CB203.

[0106] The CPU 91 prints one print line based on the transport cycle set in S16 (S17). The CPU 91 controls the motor 24 based on the transport cycle and causes the heating element to generate heat based on the print cycle.

[0107] The CPU 91 determines whether printing of 12 print lines has been completed (S18). If the CPU 91 determines that printing of 12 print lines has not been completed (S18: NO), the process returns to S16. If the CPU 91 determines that printing of 12 print lines has been completed (S18: YES), the CPU 91 determines whether printing of all print lines that make up the print data has been completed (S19). If the CPU 91 determines that printing of all print lines has not been completed (S19: NO), the process returns to S7. If the CPU 91 determines that printing of all print lines has been completed (S19: YES), the process returns to S1.

[0108] As described above, the CPU 91 of the printer 1 switches the control mode of the motor 24 between the first mode and the second mode (S3). The acceleration / deceleration time in the second mode is longer than that in the first mode. The amount of jerk change in the second mode is smaller than that in the first mode.

[0109] According to this, the printer 1 switches the control of the motor 24 between a first mode for producing printouts of normal quality and a second mode for producing printouts of high quality. The acceleration / deceleration time in the second mode is longer than that in the first mode, and the amount of jerk change in the second mode is smaller than that in the first mode. Therefore, in the second mode, when the CPU 91 changes the speed of the motor 24, there are no sudden changes in the speed and acceleration of the motor 24. This allows the printer 1 to accelerate the motor 24 while ensuring the quality of the printout. Therefore, the printer 1 can print quickly even when producing high-quality printouts.

[0110] In the second mode, the acceleration time of the motor 24 from one speed to the other is shorter than the deceleration time of the motor 24 from the other speed to the first speed. This allows the motor 24 to accelerate from one speed to the other in a short time in the second mode. This allows the printer 1 to print more quickly, even when producing high-quality printed materials.

[0111] When accelerating the motor 24 from the start speed to speed V4 in the second mode, the CPU 91 accelerates the motor 24 from the start speed to speed V3 in the second mode, and then accelerates the motor 24 from speed V3 to speed V4 in the second mode. As a result, when the motor 24 accelerates to speed V4, which is faster than speed V3, the fastest printing speed, it does not accelerate from the start speed to speed V4 in one go. This allows the printer 1 to transport the medium 10 stably, even when transporting the medium 10 at speed V4, which is faster than the fastest printing speed.

[0112] The thermal head 31 has an array of multiple heating elements, which can be divided into one to three blocks. The thermal head 31 is powered for each block individually to perform printing. The CPU 91 determines the speed of the motor 24 when printing the next 24 print lines based on the maximum number of blocks in the next 24 print lines. In this way, the CPU 91 changes the speed according to the number of blocks, allowing the thermal head 31 to print in synchronization with the transported medium 10. This allows the printer 1 to guarantee the quality of the printed matter.

[0113] The present invention can be modified in various ways from the above-described embodiment. The various modifications described below can be combined with each other as long as no contradiction occurs.

[0114] In the above embodiment, the platen roller 26 transports the medium 10. However, the printer 1 may have, for example, a belt conveyor including an endless belt, and the belt conveyor may transport the medium 10. The platen roller 26 may be provided with an encoder that outputs a signal corresponding to the rotational position of the platen roller 26. The CPU 91 may perform feedback control of the transport based on the signal output by the encoder provided on the platen roller 26.

[0115] In the above embodiment, the motor 24 is a stepping motor. However, the motor 24 may be, for example, a servo motor. In this case, the motor 24 may be provided with an encoder that outputs a signal corresponding to the rotational position of the motor 24. The CPU 91 may perform feedback control of the conveyance based on the signal output by the encoder provided in the motor 24.

[0116] If the acceleration / deceleration time in the first mode is shorter than the acceleration / deceleration time in the second mode and the change in jerk in the first mode is greater than the change in jerk in the second mode, the first mode may be changed as appropriate. In the above embodiment, in the first mode, the CPU 91 accelerates / decelerates the motor 24 at a constant acceleration. Alternatively, the CPU 91 may increase / decrease the acceleration of the motor 24 in proportion to time, for example.

[0117] In the first mode, when accelerating from one speed to another, the CPU 91 does not need to perform control in which the positive and negative values ​​are reversed relative to the control for decelerating from the other speed to one speed. The acceleration time when accelerating the motor 24 from one speed to the other speed may be longer than the acceleration time when accelerating the motor 24 from the other speed to one speed. The acceleration time when accelerating the motor 24 from one speed to the other speed may be shorter than the acceleration time when accelerating the motor 24 from the other speed to one speed.

[0118] If the acceleration / deceleration time in the second mode is longer than the acceleration / deceleration time in the first mode and the change in jerk in the second mode is smaller than the change in jerk in the first mode, the second mode may be changed as appropriate. In the above embodiment, in the second mode, the CPU 91 increased / decreased the acceleration of the motor 24 in proportion to time. In contrast, the CPU 91 may increase / decrease the acceleration of the motor 24 in proportion to the square of time. In other words, the CPU 91 may change the acceleration of the motor 24 over time in a curved manner.

[0119] In the above embodiment, when the CPU 91 controls in the second mode, the acceleration time required to accelerate from one speed to the other speed is shorter than the deceleration time required to decelerate from the other speed to the one speed. In contrast, when the CPU 91 controls in the second mode, the acceleration time required to accelerate from one speed to the other speed may be longer than the deceleration time required to decelerate from the other speed to the one speed. When the CPU 91 controls in the second mode, the acceleration time required to accelerate from one speed to the other speed may be the same as the deceleration time required to decelerate from the other speed to the one speed.

[0120] When accelerating from the start speed to speed V4 in the second mode, the CPU 91 may not accelerate from the start speed to speed V3 in the second mode and then accelerate from speed V3 to speed V4 in the second mode. The CPU 91 may accelerate from the start speed to speed V2 in the second mode and then accelerate from speed V2 to speed V4 in the second mode. The CPU 91 may accelerate from the start speed to speed V1 in the second mode and then accelerate from speed V1 to speed V4 in the second mode. The CPU 91 may accelerate from the start speed to speed V2 in the second mode, accelerate from speed V2 to speed V3 in the second mode, and then accelerate from speed V3 to speed V4 in the second mode.

[0121] In the above embodiment, the thermal head 31 prints on the medium 10 using heat. However, the printer 1 may have, for example, an inkjet head that ejects ink, and the inkjet head may print on the medium 10. The medium 10 is not limited to thermal paper and may be, for example, a plastic film or fabric. The shape of the medium 10 is not limited to a strip and may be, for example, a sheet. The medium 10 does not have to be wound around the spool 35 of the holder 3.

[0122] The thermal head 31 does not need to be able to divide the multiple heating elements. In the above embodiment, the thermal head 31 could divide the multiple heating elements into a maximum of three. In contrast, the thermal head 31 only needs to divide the multiple heating elements into two or more, and the number of divisions may be changed as appropriate. The CPU 91 does not need to change the speed of the motor 24 depending on the number of blocks supplying power to the thermal head 31.

[0123] In the above embodiment, the motor 24 can change its speed to speed 0, speed V1, speed V2, speed V3, and speed V4. However, the motor 24 only needs to be able to change to two or more speeds, and the speeds to which the motor 24 can change may be changed as appropriate. For example, the motor 24 may change its speed to speed 0, speed V1, and speed V3.

[0124] In the above embodiment, the motor 24 changes speed in five stages: speed 0, speed V1, speed V2, speed V3, and speed V4. However, the motor 24 may be capable of changing speed in six or more stages. The motor 24 may change speed in six stages, for example: speed 0, speed V1, speed V2, speed V3, speed V4, and speed V5. Note that speed V5 is different from speed 0, speed V1, speed V2, speed V3, and speed V4. Speed ​​V5 may be faster or slower than speed V3.

[0125] The printer 1 may use, for example, a microcomputer, an ASIC (Application Specific Integrated Circuits), an FPGA (Field Programmable Gate Array), etc. for control instead of the CPU 91. The main processing may be distributed using multiple CPUs 91, or may be performed by combining the CPU 91 with an ASIC, etc.

[0126] Non-transitory storage media such as the ROM 92 and the storage device 94 may be any storage media capable of retaining information regardless of the period for which the information is stored. A non-transitory storage medium need not include a temporary storage medium (e.g., a transmitted signal). The control program 52, acceleration tables 60A-69A, 60B-69B, deceleration tables 70A-79A, 70B-79B, etc. may be stored in the storage device 94 or the like. In this case, the control program 52, acceleration tables 60A-69A, 60B-69B, deceleration tables 70A-79A, 70B-79B, etc. may be downloaded from a server connected to a network, i.e., transmitted as a transmission signal. The programs, etc. may be stored in a non-transitory storage medium such as an HDD provided in the server.

[0127] Printer 1 is an example of a "printer" of the present invention. Medium 10 is an example of a "medium" of the present invention. Thermal head 31 is an example of a "printing unit" of the present invention. Platen roller 26 is an example of a "conveying unit" of the present invention. Motor 24 is an example of a "motor" of the present invention. CPU 91 is an example of a "control unit" of the present invention. Speed ​​0 is an example of a "first speed" of the present invention. Speed ​​V3 is an example of a "second speed" or "fastest printing speed" of the present invention. Speed ​​V4 is an example of a "third speed" of the present invention. [Explanation of symbols]

[0128] 1. Printer 24 motor 26 Platen roller 31 Thermal head 91 CPU

Claims

1. a printing unit that prints on the medium; a transport unit that transports a medium toward the printing unit; a motor that rotates to drive the conveying unit; a control unit, The control unit a first mode for controlling the rotation of the motor; a second mode different from the first mode, in which a length of an acceleration / deceleration time for changing the motor from a starting speed to a target speed is longer than a length of the acceleration / deceleration time in the first mode, and a change in jerk when changing the motor from the starting speed to the target speed is smaller than a change in jerk in the first mode; A printer characterized by being controlled by switching between the above.

2. In the acceleration / deceleration time in the second mode, an acceleration time for accelerating from a first speed that is the start speed to a second speed that is the target speed and is faster than the first speed is shorter than a deceleration time for decelerating from the second speed that is the start speed to the first speed that is the target speed.

2. The printer according to claim 1, wherein:

3. The control unit In the second mode, when accelerating from the start speed, which is faster than the fastest printing speed based on the printing cycle of the printing unit, to a third speed, which is the target speed and is faster than the fastest printing speed, control of the motor based on the second mode from the start speed to the fastest printing speed is executed, and then control of the motor based on the second mode is executed from the fastest printing speed to the third speed.

2. The printer according to claim 1, wherein:

4. the printing unit is a thermal head in which a plurality of heating elements are arranged, the plurality of heating elements can be divided into a plurality of blocks, and power is supplied to each of the blocks to perform printing; The control unit In the second mode, the speed of the motor is changed depending on the number of the blocks that supply power to the thermal head.

2. The printer according to claim 1, wherein:

5. A method for controlling a printer including a printing unit that prints on a medium, a transport unit that transports the medium toward the printing unit, and a motor that drives the transport unit by rotation, comprising: a first mode for controlling the rotation of the motor; a second mode different from the first mode, in which the length of an acceleration / deceleration time for changing the motor from a starting speed to a target speed is longer than the acceleration / deceleration time in the first mode, and the amount of change in jerk when changing the motor from the starting speed to the target speed is smaller than the amount of change in jerk in the first mode; A control method characterized by controlling by switching between the above.

Images