JP2991325B2 - Color thermal printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color thermal printer.

[0002]

2. Description of the Related Art FIG.
FIG. 1 is a cross-sectional view showing a conventional printing apparatus disclosed in Japanese Patent Application Publication No. 5-105, in which 101 is an apparatus main body, 102 is a paper discharge tray, 103 is a paper cassette, and 100 is a paper cassette 1.
Cut paper loaded on 03, platen roller 104,
105 is a thermal head, 106 is an ink sheet, 10
7 is a supply section of the ink sheet 106, 108 is a winding section of the ink sheet 106, 115 is an aligning roller for aligning the leading end of the paper, 120 is a pinch roller on the paper supply side, 121 is a brake means, 123 is a paper path, 12
4, 125 is a paper transport guide, 129 is a paper discharge roller, 1
30 is a pinch roller on the paper discharge side, 131 is a paper circuit, 13
Reference numerals 2 and 133 denote paper conveyance guides, 134 denotes a paper path, 13
5, 136 are paper conveyance guides; 140, 141 are paper sensors on the paper supply side and paper discharge side, respectively; 143 is a pulse motor of a main drive source; 144 is a pulse motor for paper supply;
Is a pulse motor for winding the ink sheet, 147 is a plunger type solenoid for bringing the pinch roller 120 on the paper supply side into and out, 148 is a plunger type solenoid for making the pinch roller 130 on the paper discharge side in and out, 149 is a power supply, and 150 is an electric power supply. A control unit for controlling the system, 170 and 171 are paper guides (brake plates), 173 is a plunger type solenoid of a driving source for bringing a thermal head into and out of contact with a platen roller, and 1.
Numeral 74 denotes a rotary solenoid for rotating a brake plate 171 which also serves as a paper conveyance guide, and numeral 175 denotes a friction member.

Next, the operation will be described. Control unit 150
When a print command is issued, the feed roller 116 is rotated by driving the pulse motor 144. As the paper feed roller 116 rotates, the uppermost sheet of the cut paper (print paper) 100 loaded on the paper cassette 103 is fed from the paper cassette 103. Cut paper 100 fed
Passes through the paper path 123 formed by the paper guides 124 and 125, reaches the aligning roller 115, and the displacement of the leading end of the cut sheet 100 is subjected to the flyment. Thereafter, the driving of the pulse motor 143 causes the aligning roller 115 to rotate. By the rotation of the aligning roller 115, the cut paper 100 is guided by the paper guides 170 and 171 and the pinch roller 120 on the paper feed side is driven by the solenoid 1
47 presses against the platen roller 104.

Here, the thermal head 105 is pressed against the platen roller 104 by a solenoid 173, and the pinch roller 130 on the paper discharge side is pressed against the platen roller 104 by a solenoid 148. In this state, the pulse motor 146 is driven to wind up the ink sheet 106, and at the same time, the pulse motor 143 is driven to rotate the platen roller 104 counterclockwise, so that the cut sheet 100 is wound around the platen roller 104. .

The pinch roller 120 on the paper feed side is connected to the solenoid 1
47, the thermal head 105 is separated from the platen roller 104 by the solenoid 173.
, The rotary solenoid 174 to which the brake plate 171 is attached is rotated clockwise, and the friction material 175 is rotated.
When the platen roller 104 is slightly rotated clockwise while the cut sheet 100 is sandwiched between the platen roller 104 and the brake plate 171, the platen roller 104 does not bend between the friction material 175 and the sheet discharge side pinch roller 130 without bending. It will be wrapped around. In this state, the pinch roller 120 on the paper feed side is moved by the solenoid 147 to the platen roller 104.
At the same time, the rotary solenoid 174 is rotated counterclockwise to back the cut sheet 100 to the printing start position.

The thermal head 105 is connected to the platen roller 1
04 and press the ink sheet 108 with the pulse motor 1
46, the platen roller 104
Of the thermal head 1
05 is controlled to be heated, recording is started, and a predetermined area is recorded.

When the thermal head 105 is mounted on the platen roller 1
Then, the platen roller 104 is rotated clockwise so as to be moved back by a predetermined area. The recording operation;
The paper back operation is repeated a predetermined number of times, and the recording on the cut paper 100 is completed. Thereafter, the cut sheet 100 is discharged to the discharge tray 102 by the discharge roller 129, and the operation is completed.

[0008]

Since the conventional recording apparatus is constructed as described above, a large number of drive sources such as pulse motors and solenoids must be used, and a control unit for controlling the drive sources accordingly. Not only becomes complicated, but also because the drive system is discrete, there is a problem that the device becomes large.

Further, when printing, it is necessary to determine the position of the paper accurately and print it. However, since the drive system has gears and belts, there is a backlash, and therefore accurate positioning is required. There was a problem that it was difficult to do.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems described above, and a control unit for integrating a drive system, reducing the number of drive sources, simplifying the mechanism of the drive system, and controlling the drive system. And to obtain a small and inexpensive printer, and a printer capable of performing accurate alignment during printing operation.

[0011]

According to a first aspect of the present invention, there is provided a color thermal printer in which a plurality of rotary cams and a means for transmitting power are integrally formed. And a pair of cams are disposed on both sides of the platen roller and supported rotatably independently of the rotation of the platen roller. When the pair of power transmission means is rotated from one drive source, The pair of cams are configured to rotate in synchronization with each other, and the pressing / separating operation of the conveyance printing member is the operation of pressing / separating the paper plate and the paper feed roller. Operation of pressing / separating the pinch roller The operation of pressing / separating the pinch roller and the platen roller is selectively performed according to the cam operation.

In a color thermal printer according to a second aspect of the present invention, a plurality of rotary cams and a means for transmitting power are integrally formed, and the plurality of integrally formed cams are paired. In addition to being arranged on both sides of the platen roller,
The pair of cams are rotatably supported independently of the rotation of the platen roller, and the pair of cams are rotated in synchronization with rotation of the pair of power transmission means from one driving source,
Also, of the pressing / separating operation of the conveyance printing member, the operation of pressing / separating the paper plate and the paper feed roller The operation of pressing / separating the thermal head and the platen roller The pressing / contacting of the pinch roller and the platen roller Separation Operation The operation of pressing and separating the paper ejection roller and the paper ejection contact roller is selectively performed in accordance with the cam operation.

According to a third aspect of the present invention, there is provided a color thermal printer according to the first or second aspect, wherein the discharge contact pressure roller provided opposite to the platen roller and the discharge contact pressure roller are rotated. A paper discharge contact pressure roller shaft that freely supports, a pair of power transmission means is disposed on both sides of the discharge pressure contact roller, and the power transmission means is fixed to the discharge paper contact pressure roller shaft; When the pair of power transmission means is driven by one drive source, the pair of power transmission means on the platen roller side is rotated through the pair of power transmission means,
The pair of cams are configured to rotate synchronously.

A color thermal printer according to a fourth aspect of the present invention includes a plurality of cams integrally formed and driven by a single drive source, and includes a sheet plate and a feeder in the pressing / separating operation of the transport printing member. First operation of pressing the paper roller against the second operation Second operation of pressing the thermal head and the platen roller against the third operation Third operation of pressing the pinch roller with the platen roller The third operation pressing the discharge roller and the discharge contact pressure roller The operation of step 4 is performed by the cam, and the operation area based on the operation position of the cam is the first operation area of the paper feeding operation area. The second operation area of the paper beam / sheet heading / paper back operation area. The third operation area in the wrapping / printing area is allocated to the fourth operation area in the paper discharge area. In the first operation area, the first operation and the third operation are performed. In the second operation area, the third operation is performed. In the third operation area, the second operation and the third operation are performed. In the fourth operation area, the fourth operation is performed, and the operation order is changed to the first operation area, the third operation area, and the second operation area. Operating area,
Operate in the order of the third operation area and the fourth operation area, and
The second operation area and the third operation area are set according to the number of colors to be printed.
It is configured to perform control for inserting a reciprocating operation with the operation area.

According to a fifth aspect of the present invention, there is provided a color thermal printer having a mechanism for performing a printing operation by rotating a cam by using a power transmission means from one drive source, and printing at a predetermined rotation position of the cam. An initial sensor for generating an initial signal for setting an initial position of the operation, cam rotation angle detecting means for detecting the rotation angle of the cam based on the initial signal, and setting in advance from the initial signal generation position by turning on the power. The cam is rotated by the first set rotation angle, and the cam is rotated reversely from the rotation position to the initial signal generation position, and the difference between the reverse rotation angle and the first set angle is derived as a backlash amount. And a correcting means for correcting the initial position based on the backlash amount.

According to a sixth aspect of the present invention, there is provided a color thermal printer having a mechanism for performing a printing operation by rotating a cam from one drive source by using a power transmission means, and printing at a predetermined rotational position of the cam. An initial sensor for generating an initial signal for setting an initial position of the operation, cam rotation angle detecting means for detecting the rotation angle of the cam based on the initial signal, and setting in advance from the initial signal generation position by turning on the power. The cam is rotated by the first set rotation angle, and the cam is rotated reversely from the rotation position to the initial signal generation position, and the difference between the reverse rotation angle and the first set angle is derived as a backlash amount. Backlash amount detecting means for correcting the initial position based on the backlash amount, and performing forward / reverse rotation of the cam during printing operation. In response to work, in which a correction means for correcting the cam rotational position based on the backlash.

According to a seventh aspect of the present invention, there is provided a color thermal printer according to the fifth or sixth aspect, wherein the cam is rotated from the standby position to the initial position when printing is continuously performed on the second and subsequent sheets. If the difference between the backlash amount and the preset second set rotation angle exceeds a predetermined value, the backlash amount is derived again without turning off the power by the backlash amount detection means, and the backlash amount derived again by the correction means. Re-correction determining means for determining and instructing to correct the cam rotation position in accordance with the above.

According to an eighth aspect of the present invention, in the color thermal printer according to any one of the fifth to seventh aspects, the correction means corrects if the backlash amount is equal to or less than a preset limit backlash amount. Correction means, or
If the amount of backlash is equal to or larger than the limit backlash, any one of the correcting means for correcting the backlash is used.

According to a ninth aspect of the present invention, in the color thermal printer according to any one of the fifth to eighth aspects, if the backlash amount is equal to or more than a predetermined value, it is determined that the cam drive system is abnormal and an alarm signal is issued. It is provided with a cam drive system abnormality notification means that is generated.

According to a tenth aspect of the present invention, there is provided a color thermal printer according to the fifth aspect, wherein
If the backlash amount is equal to or greater than the first predetermined value, it is determined that the cam drive system is abnormal, an alarm signal is generated, and the backlash amount is set to a second predetermined value (second predetermined value ≧ first predetermined value). Value), there is provided a cam drive system abnormality notification means for sending a printing operation stop signal.

[0021]

In the color thermal printer according to the first and second aspects of the present invention, a plurality of integrally formed rotary cams are disposed at both ends of a platen roller and driven by one driving source. Since the pressing / separating operation of the predetermined conveyance printing member is performed, the driving system is simplified, the driving source is reduced, and the size is reduced.

In the color thermal printer according to the third aspect of the present invention, the driving of the cam is driven by a pair of power transmission means provided on both sides of the paper discharge pressure roller, so that the driving system can be simplified and downsized.

In the color thermal printer according to a fourth aspect of the present invention, the pressing / separating operation by the cam is selectively performed, the operating area of the cam is allocated, and the pressing / separating operation by the cam is performed according to the operating area. Is selectively performed, and the operation of the cam is controlled to perform the operation region in a predetermined operation order. Therefore, the mechanism of the drive system and the control system can be simplified and the size can be reduced.

The color thermal printer according to claim 5 of the present invention detects the backlash amount of the cam drive system each time the power is turned on, and corrects the displacement of the initial position of the cam based on the backlash amount. The initial position control of the cam can be performed with high accuracy without increasing the accuracy of the components constituting the drive system.

According to the color thermal printer of the present invention, the amount of backlash of the cam drive system is detected each time the power is turned on, and based on this amount of backlash, the displacement of the initial position of the cam is corrected, and printing is performed. The cam rotation position is corrected based on the backlash amount in accordance with the forward / reverse rotation of the cam during operation, so that the accuracy of the cam is improved without increasing the accuracy of the components that make up the cam drive system. Initial position adjustment and cam position adjustment control during each printing operation can be performed.

In the color thermal printer according to a seventh aspect of the present invention, when printing is continuously performed on the second and subsequent sheets, the shift amount of the cam standby position is detected, and the shift amount of the cam standby position is used to correct the cam standby position. If the required cam rotation deviation angle is exceeded, the cam standby position is re-corrected, so that it is possible to prevent problems caused by the deviation amount of the cam standby position.

According to the color thermal printer of the present invention, if the backlash amount is equal to or less than a predetermined limit backlash amount or equal to or greater than the limit backlash amount, the color thermal printer is corrected. Set the appropriate backlash amount.

In the color thermal printer according to the ninth aspect of the present invention, if the backlash amount is equal to or more than a predetermined value, it is determined that the cam drive system is abnormal, and an alarm signal is generated, so that the abnormality of the printer can be accurately grasped. it can.

In a color thermal printer according to a tenth aspect of the present invention, if the backlash amount is equal to or more than the first predetermined value, it is determined that the cam drive system is abnormal, an alarm signal is generated, and the backlash amount is reduced to the first predetermined value. 2 predetermined value (second
(Predetermined value ≧ first predetermined value), a printing operation stop signal is transmitted to accurately grasp the abnormality of the printer, and also to protect the printer and prevent defective printing.

[0030]

【Example】

Embodiment 1 FIG. An embodiment according to the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing the configuration of a drive system of a color thermal printer. In the figure, solid arrows 43 indicate power transmission, and broken lines 44 indicate control signal transmission. The drive system is composed of three drive systems, 45 is an ink sheet drive system for winding the ink sheet 10, 46 is a paper transport drive system for transporting the paper 30 (not shown), and 47 is an integrated drive system.

The pulse motor 22 which is a driving source of the ink sheet driving system 45 transmits a driving force to the ink sheet winding section 12 via a gear train 31 and a torque limiter 32.
Further, since the ink sheet supply unit 11 is connected to the brake unit 33, the ink sheet 10 can be wound up by the pulse motor 22 without slack. The position of the ink sheet 10 is detected by the ink sensor 29.

The pulse motor 21 as a drive source of the paper transport drive system 46 is a drive source for transporting the paper 30 (not shown), and the platen roller 15, the paper feed roller 7, and the discharge The paper roller 19 is driven. Further, the sheet supply side and sheet discharge side pinch rollers 14 and 16 are driven from the platen roller 15 via a gear train 35. Pinch roller 1
4 and 16, torque limiter (one-way clutch)
Brake parts 38 and 39 are connected via 36 and 37. The position of the sheet 30 (not shown) is detected by the sheet-side sensor 27 and the sheet-side sensor 28.

The pulse motor 23, which is the drive source of the integrated drive system 47, drives the cam train 51 integrally formed via the gear train 40. Of the cam rows 51, the paper feed cam 51
-2 moves the paper plate 5 (cassette plate) in conjunction with the lever 41. The paper feed pinch cam 51-3 is
The sheet feeding pinch roller 14 is moved toward and away from the platen roller 15. The paper ejection cam 51-4 causes the paper ejection side pinch roller 16 to contact and separate from the platen roller 15, and furthermore, the paper ejection roller 19
Is brought into contact with or separated from the paper discharge contact pressure roller 50 (not shown). The head cam 51-5 brings the thermal head 13 into and out of contact with the platen roller 15. The position detection of the cam row 51 is performed by the initial sensor 26 linked to the lever 41. The above operation is controlled by the control unit 25.

Next, the arrangement of the present invention will be described.
FIG. 2 is a cross-sectional view of the apparatus showing an arrangement configuration. In the figure, reference numeral 1 denotes an apparatus main body; 2, a paper tray;
Is a paper plate, 5 is a paper plate on which the paper 30 is loaded, 6 is a separation claw, 7 is a paper feed roller for feeding the uppermost one of the papers 30 loaded on the paper plate 5, 8, 9 is a paper guide,
10 is an ink sheet, 11 is an ink sheet supply unit, 12
Denotes a thermal head, 13 denotes a thermal head, 14 denotes a pinch roller on a paper feed side, 15 denotes a platen roller, 16 denotes a pinch roller on a paper discharge side, 17 and 18 denote paper guides, 19 denotes a paper discharge roller, and 20 denotes a paper discharge contact. A pressure roller 21, a paper feed roller 7,
A pulse motor 22 for driving the feed-side pinch roller 14, the platen roller 15, the discharge-side pinch roller 16, and the discharge roller 19 via respective gear trains (not shown);
Is a pulse motor for winding the ink sheet 10, 24 is a power supply, 25 is a control unit, 26 is an initial sensor for detecting the position of a cam row 51 (not shown), and 27 and 28 detect the position of the paper 30 respectively. The paper feed sensor and the paper discharge sensor 29 are ink sensors that detect the position of the ink sheet 10. Reference numeral 23 denotes a pulse motor that drives the integrated drive system 47.

Next, the configuration of the integrated drive system 47 will be described. FIG. 3 is a view showing a cross section AA of FIG. 2. In FIG. 3, reference numeral 50 denotes a discharge pressure roller, and reference numeral 51 denotes a cam row which is rotatably supported at both ends of the platen roller 15 and can rotate independently of the rotation of the platen roller 15. Reference numeral 52 denotes a paper discharge pressure roller shaft that rotatably supports the paper discharge pressure roller 50 and is rotatable independently of the rotation of the paper discharge pressure roller, 53 is a parallel pin, and 54 is a paper discharge pressure roller shaft 52. The gear is fixed by the parallel pin 53. The gear 54 receives power transmitted from the pulse motor 23 via a gear train 40 (not shown), meshes with a gear 51-1 formed integrally with the cam train 51, and the pair of cam trains 51 is synchronized. And rotate. The cam row 51 includes a paper feed cam 51-2, a paper feed pinch cam 51-3, a paper discharge cam 51-4, and a head cam 51-5.
Are formed integrally. The configuration of the driven portion of the cam row 51 will be described sequentially.

FIG. 4 is a cross-sectional view taken along the line BB of FIG. 3, and shows a configuration in which the paper plate 5 and the initial sensor 26 are driven. In the figure, 41-1, 41-2, 4
1-3 are the rotation center, the point of force, and the point of action of the lever 41, respectively. Reference numeral 70 denotes a paper contact pressure spring, and the paper 30 (not shown) stacked on the upper surface of the paper plate 5 by the paper feed roller 7
The sheet 30 presses the sheet 30 against the sheet feed roller 7 via the sheet plate 5 to apply a contact pressure necessary to feed the uppermost sheet of the sheet. 26-1 is an actuator of the initial sensor 26, 5-1 is a pin integrally attached to the paper plate 5, and moves the actuator 26-1.
This is the spring of the paper contact pressure spring 70.

When the paper feed cam 51-2 rotates, the paper 30 (not shown) is raised together with the paper plate 5 by the paper pressure spring 70 at a certain angular timing, and a contact pressure necessary for paper feeding is generated. When the paper feed roller 7 rotates in the direction of the arrow,
Paper feeding starts. At a certain angular timing, the paper plate 5 overcomes the force of the paper contact pressure spring 70 and descends, and the paper 30 separates from the paper feed roller 7. In this state, the sheet 30 (not shown) can be set along the sheet tray 2 (not shown). Further, when the paper plate 5 moves up and down, the actuator 26-
1 is movable, so that the output signal of the initial sensor 26 can be changed.

FIG. 5 is a cross-sectional view taken along the line CC of FIG. 3, and shows a structure in which the paper feed side pinch roller 14 is driven. In the drawing, reference numeral 80 denotes a paper-feed-side pinch lever for rotatably supporting the paper-feed-side pinch roller 14, and 81 denotes a paper-output-side pinch roller 16.
A pinch lever 82 is a pinch contact pressure spring that presses the paper supply side pinch roller 14 and the paper discharge side pinch roller 16 against the platen roller 15.
1, 81-1. Paper feed side pinch lever 8
0 and the discharge-side pinch lever 81 are connected to the discharge contact pressure roller shaft 5.
2 is rotatably supported.

When the feed pinch cam 51-3 rotates, the pinch roller 14 separates from the platen roller 15 at a certain angular timing via a cam follower 14-1 attached to the feed pinch roller 14. Paper ejection side pinch roller 1
Similarly, the sheet 6 is separated from the platen roller 15 by rotation of a sheet discharge cam 51-4 described later. The purpose of this configuration is, for example, to prevent the pinch rollers 14 and 16 from being pressed against the platen roller 15 for a long time by the pinch contact pressure spring 82 during printing standby, and to prevent the platen roller 15 from being damaged by indentations or the like. is there.

FIG. 6 is a cross-sectional view taken along the line DD of FIG. 3, and shows a structure in which the discharge roller 19 and the discharge-side pinch roller 16 are driven. In the figure, reference numeral 90 denotes a lever having a cam follower 90-2, which rotatably supports the discharge roller 19, and which is driven by rotation of the discharge cam 51-4 about a rotation center 90-1; Is a paper discharge contact pressure spring that presses against the paper discharge pressure roller 50.

When the discharge cam 51-4 rotates, the discharge roller 19 separates from the discharge contact pressure roller 50 at a certain angle timing. The purpose of this configuration is that the speed at which the paper 30 (not shown) is conveyed by the rotation of the platen roller 15 by the pinch rollers 14 and 16 is slightly different from the speed at which the paper 30 is conveyed by the rotation of the discharge roller 19. In this case, the paper 30 (not shown) is prevented from stretching between the platen roller 15 and the paper discharge roller 19.
The paper discharge side pinch roller 16 is moved by the paper discharge cam 51-4 in synchronization with the timing at which the paper supply side pinch roller 14 is moved away from the platen roller 15.

FIG. 7 is a cross-sectional view taken along the line EE of FIG. 3, and shows a structure in which the thermal head 13 is brought into contact with and separated from the platen roller 15. In the figure, 95 is the thermal head 1
3, a head contact pressure spring for pressing the plate 3 against the platen roller 15,
13-2 is a cam follower attached to the thermal head 13. When the head cam 51-5 rotates, at a certain angle timing, the thermal head 13 moves the cam follower 13-.
2 comes into contact with and separates from the platen roller 15.

Next, the assignment of the angular timing of the cam row 51 will be described with reference to FIG. The period during which the cam row 51 makes one round is divided into four parts, the timing of the paper feed cam 51-2 at which the paper supply plate 5 comes into contact with and away from the paper supply roller 7, and the paper supply side pinch roller 14 comes into contact with and away from the platen roller 15. The timing of the paper feed pinch cam 51-3, the timing of the head cam 51-5 at which the thermal head 13 contacts and separates from the platen roller 15, and the paper discharge side pinch roller 16
8 and the timing at which the paper discharge roller 19 contacts and separates from the paper discharge contact pressure roller 20 are assigned as shown in FIG. FIG. 9 shows the relationship between the angle of the cam row and the operation, which also shows the curve of the cam.

In FIG. 8 and FIG. 9, in this allocation, the operation areas are allocated as follows according to the rotation (operation position) of the cam row. A first operation area of a sheet feeding operation area, a second operation area of a sheet beam / sheet heading / sheet back operation area,
Third operation area of paper supply winding / printing area, fourth operation area of paper discharge area

Each transport roller, thermal head,
Of the pressing / separating operations of the transport printing members such as paper plates,
As described above, each cam performs the following operation. First operation for pressing the paper plate and the paper feed roller. Second operation for pressing the thermal head and the platen roller. Third operation for pressing the pinch roller and the platen roller. Discharge roller and discharge pressure roller 4th operation to press

The cam position θ ₀ is a position for the sheet discharging operation simultaneously with the reference angle of the cam row 51. In addition, this position is during standby. θ ₁ is the position of the feeding operation. θ ₂ is a sheet beam, out of paper head, and the position of the paper reverse operations. θ ₃ is wrapping paper, and is a position of the printing operation. The cam row 51
Is configured to be able to rotate forward and reverse.

The operation of the cam array shown in FIG.
This shows the printing operation. To perform color printing, printing is performed by repeating θ ₃ and θ ₂ according to the number of colors.

Next, detection of the reference angle θ ₀ of the cam row 51 will be described. FIG. 11 shows the relationship between the sensor output of the initial sensor 26 and the rotation angle of the cam row 51. In the figure, θ ₅ is the rotation angle of the cam row 51 for detecting the detection voltage V ₀ of the initial sensor 26, and θ ₆ is the cam row 5 in standby.
The angle of 1 and θ _th is a predetermined initial back angle amount. The operation (initial operation) of detecting the reference angle θ ₀ of the cam row 51 is based on the angle θ _{6 of the} cam row 51.
From, the normal rotation of the cam column 51 through an angle theta ₅ of the cam rows 51 for detecting a detection voltage V _0. Thereafter, the position rotated backward by the back angle θ _th is defined as the reference angle θ ₀ of the cam row 51.
Thereafter, by counting the number of pulses input to the pulse motor 23, the angle of the cam row 51 is recognized.

Next, the operation will be described with reference to the flowchart of FIG. In the above configuration, the pulse motor 23
Drives, after initial operation (S1), is rotated forward cam column 51 to cam position θ ₁ (S2). When the pulse motor 21 rotates in the forward direction, the paper feed roller 7 rotates, and the uppermost sheet of the paper 30 set in the paper tray 2 is separated by the separation claw 6 and guided by the paper guides 8, 9, and Paper is fed to the sensor 27. Further predetermined amount and fed from the paper feed side sensor 27, when the leading end of the sheet is pressed against between the paper feed side pinch roller 14 and the platen roller 15 (S3), drives the pulse motor 22, until the cam position theta ₃ The cam train is rotated forward (S4). Here, the pulse motor 23 is driven, and while the ink sheet 10 is wound, the pulse motor 21 is wound.
Is rotated forward and the platen roller 15 is rotated clockwise.
1 and is pressed against the platen roller 15 and the paper discharge side pinch roller 16 to feed the paper to the paper discharge side sensor 28 (S5).

[0050] Here, by driving the pulse motor 23, to reverse the cam rows 51 until cam position θ ₂ (S6). In this state, in order to bring the sheet 30 into close contact with the platen roller 15, the pulse motor 21 is rotated forward, and after the sheet 30 is conveyed by a predetermined amount (S7), the pulse motor 21 is rotated reversely so that the leading end of the sheet 30 Back the paper 30 until it comes to the position. Further, after the paper 30 is backed by a predetermined amount (S
8) When the paper 30 is transported by a predetermined amount to the printing start position,
The cueing of the sheet 30 is completed (S9).

[0051] Here, by driving the pulse motor 23, a pulse motor driving the rotated forward until cam position θ ₃ (S10), further, drives the pulse motor 22, the platen roller 15 while Ri卷取the ink sheet 10 At the same time that the control unit 25 rotates the thermal head 1
3 is controlled to be heated, recording is started, and a predetermined area is recorded. During this time, the leading edge of the paper is
-1, the discharge roller 19 and the discharge pressure roller 20
Are transported along the paper discharge trays 3 and 4 while passing through (S11).

When the recording for one color is completed, the pulse motor 23 is driven to reverse the rotation to the cam position θ ₂ (S1).
2). Next, the pulse motor 21 is driven to back the paper 30. At this time, the trailing edge of the paper is
The sheet is guided by 8-2 and retracted between the sheet guide 9 and the sheet discharge tray 3 (S13). Here, it is determined whether or not the next color is to be recorded (S14). If the next color is to be recorded, the process returns to step S9, and after the sheet is caught (S14).
9) Recording of the second color starts. Thereafter, this operation is repeated by the number of recording colors.

[0053] If no record other colors in step S14, it is determined that the print all the color, and finally drives the pulse motor 23, is rotated forward cam column 51 to cam position θ ₀ (S15), The pulse motor 21 is driven until the paper 30 is discharged to the paper discharge trays 3 and 4 (S16).
One printing is completed.

As described above, in this embodiment, the operation of pressing and separating the paper plate to and from the paper feed roller, the operation of pressing and separating the thermal head to and from the platen roller, and the operation of pressing the pinch roller to and from the platen roller. The separating operation and the operation of pressing and separating the discharge roller against the discharge contact pressure roller are performed by integrally formed cam rows, and the position of the rotation angle of the cam row is changed to the cam row. Position detection is performed by one linked position detector.

The position detected by the position detector is set as a reference position of the cam row, and the sheet feeding operation area, the sheet beam / sheet cueing / sheet back operation area, the sheet supply winding / printing operation area are sequentially set within one rotation. Since the paper discharge operation area is allocated and the cam row is controlled to rotate forward and backward in a predetermined order, it can operate at high speed, can reduce the number of drive sources, and can simplify the control unit. An inexpensive device can be obtained.

Further, a driven portion including a thermal head and a pinch roller which come into contact with and separate from the platen roller is operated by rotatingly supporting a cam row which can rotate independently of the rotation of the platen roller at both ends of the platen roller. Therefore, a highly accurate device can be obtained.

Further, a pair of gears fixed to both ends of a paper discharge pressure roller shaft which rotatably supports a paper discharge pressure roller opposed to the platen roller and which can rotate independently of the paper discharge pressure roller are formed by a platen. The gears formed integrally with the pair of cam rows on the roller side are meshed with each other, so that the pair of cam rows are configured to rotate synchronously, so that the apparatus can be downsized.

In addition, four different operation areas are sequentially allocated in one rotation of the cam row that is rotatably supported at both ends of the platen roller, and the cam row is rotated forward and backward to align each operation area. The printing speed is increased.

Embodiment 2 FIG. In the above embodiment, the cam row performs one printing in one rotation. However, for example, one printing may be performed in a half rotation, and the next printing may be performed in the remaining half rotation. In addition, when the positions of the fulcrum, the point of force, and the point of action of the levers (41, 80, 81, 90, etc.) are changed, the pressing and separating operations can be easily reversed.

Embodiment 3 FIG. In the first embodiment, the reference angle (initial position) θ ₀ of the cam row 51 is set in advance by rotating the cam row 51 from the waiting angle θ ₆ until the detection voltage V ₀ of the initial sensor 26 is detected. Determined as a position rotated backward by the back angle amount θ _th at the time of initial,
Thereafter, the angle of the cam row 51 is recognized by counting the number of pulses input to the pulse motor 23.

In the third embodiment, the reference angle θ ₀ of the cam row 51 is corrected based on the amount of backlash θ _g of the integrated drive system 47 for driving the cam row 51, as shown in FIG. FIG. 13 is a block diagram of a main part for correcting the reference angle θ ₀ .
Reference numeral 01 denotes a cam row rotation angle detecting means for detecting the angle of the cam row 51 by counting the sensor output V ₀ from the initial sensor 26 and the number of pulses input to the pulse motor 23.

[0062] 202 is a backlash amount detecting means, after the sensor output V ₀ detected initial sensor 26, the setter 203 for setting a predetermined rotation angle theta ₇ to rotate, after a predetermined rotation angle theta ₇ rotates again rotated in the reverse direction The reverse rotation angle θ ₈ until the sensor output V ₀ of the initial sensor 26 is detected is obtained,
It consists calculator 204 for calculating the amount of backlash theta _g from the theta ₈ and theta ₇ Prefecture. 205 is a correction means for correcting the reference angle theta ₀ cams column 51 based on the backlash theta _g. The operation will be described in a sixth embodiment.

When the displacement of the initial position of the cam is corrected based on the backlash amount as in this embodiment, the initial position control of the cam can be performed with high accuracy without increasing the accuracy of the components constituting the cam drive system. it can.

Embodiment 4 FIG. FIG. 14 shows the configuration of the third embodiment.
The cam drive system abnormality notification means 206 is added as shown in FIG. 7, and the integrated drive system 47 that drives the cam train 51 requires maintenance of the drive system before the function of the drive system cannot be maintained due to wear of each part. It comprises a setting unit 207 for setting the limit backlash amount θ _gNG generated in the drive system 47 and a comparator for comparing the backlash amount θ _g with the limit backlash amount θ _gNG . The operation will be described in a sixth embodiment.

As in this embodiment, if the cam drive system abnormality signal is generated when the backlash exceeds the limit backlash, a problem caused by the backlash can be prevented in advance.

Embodiment 5 FIG. In Embodiment 3 and 4, based on the backlash theta _g, first operating region only has been corrected reference angle theta _0, assigned to the cam rows 51 that operates in the printing in Example 5 of the cam rows 51 , The cam rotation angle positions θ ₁ , θ ₂ corresponding to the second operation region, the third operation region, and the fourth operation region,
θ ₃ is also what was to be corrected on the basis of the backlash amount θ _g. That is, even for normal and reverse rotation of the cam rows 51 during the printing operation, corrects the cam rotation position on the basis of the backlash theta _g, the configuration is the same as in Example 4. The operation will be described in a sixth embodiment.

As in this embodiment, the displacement of the initial position of the cam is corrected based on the amount of backlash, and the forward and reverse rotation of the cam during the printing operation is also performed based on the amount of backlash. Therefore, the initial position of the cam can be controlled with high accuracy without increasing the accuracy of the components constituting the cam drive system.

Embodiment 6 FIG. In this embodiment, as shown in FIG. 15, a re-correction determining means 209 is added to the fifth embodiment, and it is necessary to re-correct the reference angle θ ₀ of the cam row 51 when printing the second and subsequent sheets. It is to judge whether or not.

The re-correction judging means 209 determines that the standby position of the cam row 51 has shifted due to a certain factor during standby after printing the previous page.
A setting unit 210 for setting a cam rotation deviation angle Δθ _9NG that requires correction of a standby position before the function as the integrated drive system 47 can not be maintained, and a cam row 51 is rotated forward from the standby position, and an output of the initial sensor 23 is output. A setting unit 211 for setting the theoretical cam rotation angle θ _9th until V ₀ is detected;
Cam row forward rotation angle theta ₉ until detection of the output V ₀ which the theta
And a comparator 211 for comparing the difference of _9th with Δθ _9NG .

Next, in Examples 3, 4, the positioning operation of the cam position theta ₀ through? ₄ of the cam rows 51 during printing, and a timing chart of the operation of FIG. 16, FIG. 17 and FIG. This will be described with reference to the flowchart of FIG.

After the power is turned on (S21), the predetermined values θ ₇ , θ
_th , θ ₁₀ , θ _gNG , θ _9th , Δθ _{9N G} , Δθ _0-1 , Δ
θ _1-2 , Δθ _2-3 , and Δθ _3-4 are set (S22). The cam train 51 rotates the pulse motor 23 forward from the waiting position θ ₆ until the output V ₀ of the initial sensor 26 is detected (S23). After further normal rotation for pre value amount theta ₇ (S2
4) Reverse rotation until the output V ₀ of the initial sensor 26 is detected again, and the reverse rotation angle θ ₈ at this time is measured by the cam row rotation angle detection means 201 (S25). By this theta ₇ and theta ₈ detects the backlash theta _g of integrated drive system 47 in the backlash detecting means 202 (S26).

[0072] Based on this theta _g, limit backlash and compared with a limit amount at which already value amount theta _GNG by a cam drive system abnormality notification means 206 | θ _g | For ≧ theta _GNG Display mechanical error (S27 ), | θ _g | <θ for _gNG reversed by Sundechi amount θ _th (S28), after further reversed by existing value amount θ ₁₀ (S29), it is rotated forward by θ ₁₀ + θ _g cam rows 51 match the reference angle θ ₀ of the (S30).

Next, if the printing is not continuous (S31), the cams are rotated forward by the predetermined values Δθ _0-1 , Δθ _1-2 and Δθ _2-3 sequentially to match the cam positions θ ₁ , θ ₂ and θ ₃ (S34). ), (S
35), (S36).

If there is a next color print (S3
7) Reverse the rotation by Δθ _2-3 + θ _g to set the cam position θ ₂
After adjusting to _{(S38), Δθ 2-3 + θ} g only match the cam position theta ₃ is rotated forward (S39). After repeating the steps (S38) and (S39) by the number of printing colors,
Rotate forward by Δθ _3-4 and adjust to cam position θ ₄ (S
40).

If the next page is to be printed without turning off the power, the operation starts from step (S32).
The cam line 51 is rotated forward from the standby position θ ₆ until the output V ₀ of the initial sensor 26 is detected, and the rotation angle θ ₉ at this time is measured by the cam line rotation angle detection means 201 (S32). Based on the θ ₉ and the set values θ _9th and Δθ _9NG , the re-correction determining means 209 determines Δθ _9NG and | θ ₉ −θ.
_9th | is compared, and if Δθ _9NG ≦ | θ ₉ −θ _9th |, the reference angle θ ₀ of the cam row 51 is reset (step S2).
The operation is started from 4), and if Δθ _9NG > | θ ₉ −θ _9th |, resetting θ ₀ is not necessary, and the operation is started from step (S34). The signal of Δθ _9NG > | θ ₉ −θ _9th | from the re-correction determination unit 209 in FIG. 15 is a signal that allows the correction unit 205 to correct.

As in this embodiment, the shift amount of the cam standby position is detected after the second continuous printing, and the shift amount of the cam standby position exceeds the cam rotation shift angle at which the correction of the cam standby position is required. Since the cam standby position is corrected again, it is possible to prevent a problem caused by the deviation amount of the cam standby position.

Embodiment 7 FIG. The cam drive system abnormality reporting means 206 of the _fourth , _fifth, and _{sixth embodiments} has an alarm generation function for reporting cam drive system abnormality based on a comparison between the backlash amount θ _g and the limit backlash amount θ _gNG , Correction means 205
Although the function of instructing correction and the function of both are provided, only the alarm generation function may be provided. Further, only the function of instructing the correction unit 205 to perform correction may be used. If only the function of instructing the correction means 205 to make a correction is provided, the function may be provided in the correction means 205 without using the cam drive system abnormality notification means 206.

The correction by the correction means 205 is _{performed under} the condition (| θ _g | <θ _gNG ) within the limit backlash amount θ _gNG . However, _{depending on} the set value of θ _gNG , for example, the limit backlash amount θ _gNG may be reduced, and the correction may be made when the condition (| θ _g | ≧ θ _gNG ) is equal to or greater than the limit backlash amount θ _gNG .

Further, the cam drive system abnormality notification means 206
Not only the alarm signal generation function but also the printing operation may be stopped at the same time. Further, the level may be set in two stages so that the printing operation is stopped at a set level higher than the alarm generation level.

Although the third to seventh embodiments are applied to the color thermal printer having the mechanism of the first and second embodiments, the printing is performed by rotating the cam from one drive source using a power transmission means such as a gear. The present invention is also applicable to a color thermal printer having a mechanism for performing an operation.

[0081]

As described above, according to the first and second aspects of the present invention, a predetermined driving and printing member is pressed and separated from a single driving source through a cam. Is simplified, the number of driving sources is reduced, and downsizing and cost reduction can be realized.

According to the third aspect of the present invention, the driving of the cam is driven by the pair of power transmission means provided on both sides of the discharge pressure contact roller, so that the driving system is further simplified and downsized. effective.

According to the fourth aspect of the present invention, the pressing / separating operation by the cam is selectively performed, the operating area of the cam is allocated, and the pressing / separating operation by the cam is performed according to the operating area. Is performed selectively, and the operation of the cam is controlled to perform the operation area in a predetermined operation order, so that the drive system mechanism and the control system can be simplified, and the size and cost can be reduced. There is.

According to the fifth aspect of the present invention, the backlash amount of the cam drive system is detected each time the power is turned on, and the displacement of the initial position of the cam is corrected based on the backlash amount. There is an effect that the initial position of the cam can be controlled with high accuracy without increasing the accuracy of the components constituting the drive system.

According to the sixth aspect of the present invention, the amount of backlash of the cam drive system is detected each time the power is turned on, and based on the amount of backlash, the displacement of the initial position of the cam is corrected, and printing is performed. The cam rotation position is corrected based on the backlash amount in accordance with the forward / reverse rotation of the cam during operation, so that the accuracy of the cam is improved without increasing the accuracy of the components that make up the cam drive system. There is an effect that initial position adjustment and cam position adjustment control during each printing operation can be performed.

According to a seventh aspect of the present invention, when printing is to be performed continuously for the second and subsequent sheets, the shift amount of the cam standby position is detected, and the shift amount of the cam standby position is corrected by the cam standby position. When the required cam rotation deviation angle is exceeded, the cam standby position is re-corrected, so that there is an effect that it is possible to prevent problems caused by the deviation amount of the cam standby position.

According to the eighth aspect of the present invention, if the backlash amount is equal to or less than a predetermined limit backlash amount or equal to or greater than the limit backlash amount, the correction is made. There is an effect that the backlash amount can be set in conformity with the above.

According to the ninth aspect of the present invention, if the backlash amount is equal to or more than the predetermined value, it is determined that the cam drive system is abnormal and an alarm signal is generated. There is an effect that can be grasped.

According to the tenth aspect of the present invention, if the backlash amount is equal to or larger than the first predetermined value, it is determined that the cam drive system is abnormal, an alarm signal is generated, and the backlash amount is reduced to the first predetermined value. If the second predetermined value (the second predetermined value ≧ the first predetermined value), the printing operation is stopped.
In addition to accurately grasping the abnormality of the printer, there is an effect of protecting the printer and preventing creation of a defective print.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a drive system of a thermal printer according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating an arrangement configuration of the thermal printer of FIG.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a sectional view taken along line BB of FIG. 3;

FIG. 5 is a sectional view taken along line CC of FIG. 3;

FIG. 6 is a sectional view taken along line DD of FIG. 3;

FIG. 7 is a sectional view taken along the line EE of FIG. 3;

FIG. 8 is a diagram showing the relationship between the assignment of the operation area of the cam row and the press-contact / separation of the conveyance printing member according to the first embodiment of the present invention.

FIG. 9 is a diagram showing the angle of the cam row and the operation of pressing / separating according to the first embodiment of the present invention.

FIG. 10 is a diagram showing the relationship between the angle of the cam row and the operation of the printer according to the first embodiment of the present invention.

FIG. 11 is a diagram showing a relationship between an angle of a cam row and an initial sensor output according to the first embodiment of the present invention.

FIG. 12 is a flowchart illustrating an operation of the printer according to the first embodiment of the present invention.

FIG. 13 is a main part block diagram for correcting a reference angle of a cam row according to a third embodiment of the present invention.

FIG. 14 is a main block diagram for correcting a reference angle of a cam row according to the fourth and fifth embodiments of the present invention.

FIG. 15 is a main block diagram for correcting a reference angle of a cam row according to Embodiment 6 of the present invention.

FIG. 16 is a diagram showing the relationship between the angle of a square row and the output of an initial sensor according to Embodiment 6 of the present invention.

FIG. 17 is a flowchart showing an operation of a cam row according to Embodiment 6 of the present invention.

FIG. 18 is a flowchart showing an operation of a cam row according to Embodiment 6 of the present invention.

FIG. 19 is a sectional view showing a conventional thermal printer.

[Explanation of symbols]

1 main unit, 2 paper trays, 3 and 4 output trays,
5 paper plate, 5-1 pin, 6 separation claw, 7 paper feed roller, 10 ink sheet, 11 ink sheet supply section, 12 ink sheet take-up section, 13 thermal head, 13-2, 14-1 cam follower, 14 supply Paper-side pinch roller, 15 Platen roller, 16 Discharge-side pinch roller, 17, 17-1, 17-2 Paper guide,
18, 18-1, 18-2 paper guide, 19 discharge roller, 20 discharge pressure roller, 21, 22, 23 pulse motor, 24 power supply, 25 control section, 26 initial sensor, 26-1 actuator, 27 supply Paper side sensor, 28 Discharge side sensor, 29 Ink sensor, 30
Paper, 31, 34, 35 gear train, 32 torque limiter, 33, 38, 39 brake unit, 36, 37 torque limiter, 40 gear train, 41 lever, 41-1
Center of rotation, 41-2 force point, 41-3 action point, 45
Ink sheet drive system, 46 Paper transport drive system, 47
Comprehensive drive system, 50 discharge contact pressure rollers, 51 cam rows, 5
1-1 gear, 51-2 paper feed cam, 51-3 paper feed pinch cam, 51-4 paper discharge cam, 51-5 head cam, 52 paper discharge contact roller shaft, 53 parallel pin, 54
Gear, 70 Paper contact pressure spring, 80 Paper feed side pinch lever, 80-1, 81-1 Spring hook, 81 Paper discharge side pinch lever, 82 Pinch contact pressure spring, 90 lever, 90
-1 Rotation center, 90-2 Cam follower, 91 Discharge pressure spring, 95 Head pressure spring, 201 Cam row rotation angle detecting means, 202 Backlash amount detecting means, 20
3 setter, 204 calculator, 205 correction means, 20
6 Cam drive system abnormality notification means, 207 setting device, 208
Comparator, 209 re-correction determining means, 210, 211
Setter, 212 comparator.

Continuation of front page (56) References JP-A-63-278865 (JP, A) JP-A-3-51163 (JP, A) JP-A-4-129778 (JP, A) JP-A-3-29358 (JP) , U) (58) Fields surveyed (Int. Cl. ⁶ , DB name) B41J 25/304 B41J 2/32 B41J 2/325 B41J 23/02

Claims (10)

(57) [Claims] 1. A transport printing member such as a transport roller, a thermal head, and a paper plate is disposed in accordance with a transport path of a paper, and the predetermined transport printing member is connected between the predetermined transport printing members in relation to the transport and printing operation of the paper. In a color thermal printer having a pressing / separating mechanism, a plurality of rotary cams and power transmission means for transmitting power to the cams are integrally formed, and the plurality of integrally formed cams are paired. And is disposed on both sides of the platen roller and supported rotatably independently of the rotation of the platen roller. The pair of cams are synchronized from one drive source via the power transmission means. And press / separate between the paper plate and the paper feed roller in the pressing / separating operation of the conveying / printing member. Pushing / separating the thermal head and the platen roller. Color thermal printer, characterized in the press-contact or away from work and a work pinch roller and the platen roller by being configured to selectively perform in accordance with the cam operation. 2. A transfer printing member such as a transfer roller, a thermal head, and a paper plate is disposed along a transfer path of a sheet, and the predetermined transfer print member is interposed between the predetermined transfer printing members in relation to the transfer and printing operation of the sheet. In a color thermal printer having a pressing / separating mechanism, a plurality of rotary cams and power transmission means for transmitting power to the cams are integrally formed, and the plurality of integrally formed cams are paired. And is disposed on both sides of the platen roller and supported rotatably independently of the rotation of the platen roller. The pair of cams are synchronized from one drive source via the power transmission means. And press / separate between the paper plate and the paper feed roller in the pressing / separating operation of the conveying / printing member. Pushing / separating the thermal head and the platen roller. Operation The operation of pressing and separating the pinch roller and the platen roller is performed. The operation of pressing and separating the discharge roller and the discharge pressure roller is selectively performed according to the cam operation. Color thermal printer. 3. A discharge pressure contact roller provided in opposition to a platen roller according to claim 1 or 2, and a discharge pressure contact roller shaft rotatably supporting the discharge pressure contact roller. And a pair of power transmission means is disposed on both sides of the paper discharge pressure roller, and the power transmission means is fixed to the paper discharge pressure roller shaft. When driven by, a pair of power transmission means on the platen roller side is rotated through the pair of power transmission means, and a pair of plural cams are configured to rotate synchronously. Color thermal printer. 4. A transport printing member such as a transport roller, a thermal head, and a paper plate is disposed along a transport path of the paper, and the transport printing member is interposed between the predetermined transport printing members in relation to the transport and printing operation of the paper. A color thermal printer having a mechanism for pressing and separating is provided with a plurality of cams integrally formed and driven from a single drive source, and includes a paper plate and a paper feed roller in the pressing and separating operations of the conveyance printing member. First operation for pressing the thermal head and the platen roller Second operation for pressing the pinch roller and the platen roller Third operation for pressing the discharge roller and the discharge contact pressure roller The operation is performed by the cam, and an operation area based on the operation position of the cam is a first operation area of a paper feeding operation area. 2 operation area The third operation area of the paper supply winding / printing area is allocated to the fourth operation area of the paper discharge area. In the first operation area, the first operation and the third operation are performed. In the third operation area, the second operation and the third operation are performed in the fourth operation area. The fourth operation is performed, and the operation order is changed to the first operation area, the third operation area, A second operation area,
Operate in the order of the third operation area and the fourth operation area, and
The second operation area and the third operation area are set according to the number of colors to be printed.
A color thermal printer, characterized in that the color thermal printer is configured to perform control for inserting a reciprocating operation with an operation area. 5. A transport printing member such as a transport roller, a thermal head, and a paper plate is disposed along a transport path of the paper, and the transport printing member is interposed between the predetermined transport printing members in relation to the transport and printing operation of the paper. In a color thermal printer having a mechanism for pressing and separating, a mechanism for performing a printing operation by rotating a cam using power transmission means from one drive source,
An initial sensor for generating an initial signal for setting an initial position of a printing operation at a predetermined rotational position of the cam, a cam rotation angle detecting means for detecting a rotational angle of the cam based on the initial signal, and turning on a power supply. Then, the cam is rotated by a first set rotation angle set in advance from the initial signal generation position, reversely rotated from this rotation position to the initial signal generation position, and the reversely rotated rotation angle and the first set angle A backlash amount detecting means for deriving a difference between the backlash amount and the backlash amount, and a correcting means for correcting the initial position based on the backlash amount. 6. A transport printing member such as a transport roller, a thermal head, and a paper plate is disposed along a transport path of the paper, and the transport printing member is transported between the predetermined transport printing members in relation to the transport and printing operation of the paper. In a color thermal printer having a mechanism for pressing and separating, a mechanism for performing a printing operation by rotating a cam using power transmission means from one drive source,
An initial sensor for generating an initial signal for setting an initial position of a printing operation at a predetermined rotational position of the cam, a cam rotation angle detecting means for detecting a rotational angle of the cam based on the initial signal, and turning on a power supply. Then, the cam is rotated by a first set rotation angle set in advance from the initial signal generation position, reversely rotated from this rotation position to the initial signal generation position, and the reversely rotated rotation angle and the first set angle And a backlash amount detecting means for deriving a difference between the backlash amount and the initial position on the basis of the backlash amount, and corresponding to the forward / reverse rotation of the cam during the printing operation. A color thermal printer comprising a correction means for correcting a cam rotation position based on a backlash amount. 7. A printing method according to claim 5, wherein a second rotation angle between the cam rotation angle obtained by rotating the cam from the standby position to the initial position and a second rotation angle set in advance is set when printing the second and subsequent sheets. If the difference exceeds a predetermined value, the backlash amount is derived again while the power is continued to be supplied by the backlash amount detection unit, and it is determined that the cam rotation position is corrected by the correction unit based on the derived backlash amount. A color thermal printer comprising a re-correction determining means for giving a command. 8. The method according to claim 5, wherein
The correction means may be one of a correction means for correcting if the backlash amount is equal to or less than a preset limit backlash amount, or a correction means for correcting if the backlash amount is equal to or more than the limit backlash amount. Color thermal printer. 9. The method according to claim 5, wherein
A color thermal printer comprising: a cam drive system abnormality reporting unit that determines that the cam drive system is abnormal when the backlash amount is equal to or more than a predetermined value and generates an alarm signal. 10. The apparatus according to claim 5, wherein if the backlash amount is equal to or more than a first predetermined value, it is determined that the cam drive system is abnormal, an alarm signal is generated, and the backlash amount is determined. Is a second predetermined value (second predetermined value ≧ first predetermined value), a cam drive system abnormality notification means for sending a printing operation stop signal is provided.