JPH0890850A - Thermal recorder - Google Patents

Abstract

PURPOSE: To simplify sheet conveying means and a driving system by setting the conveying directions of a record sheet from a sheet feed position to a sheet holding position and a record sheet from the sheet holding position after the recording is finished to a sheet delivery to the same, and conveying in the same direction via a one-way clutch for engaging with bent means for feeding the conveying means. CONSTITUTION: A sheet conveying unit 24 reciprocates a record sheet 22 in the state that the sheet 22 is held in a predetermined range in the state that the sheet 22 can be entered and delivered. A sheet hold releasing lever 34 is brought into contact with the unit 24 to release the holding of the sheet 2. A driven pulley 32 is disposed coaxially with a platen roller 23. A one-way clutch 33 transits and interrupts torque between the roller 23 and the pulley 32. Belt means 26 is installed between a drive pulley 27 and the pulley 32 disposed coaxially with a drive shaft 28, and fixed to the unit 24. With the structure, the conveying means and the driving system are simplified, to provide a small-sized and safe thermal recorder.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording paper reciprocating mechanism for a thermal recording apparatus using a thermal head.

[0002]

2. Description of the Related Art In recent years, thermal recording devices have been reduced in size along with colorization and high image quality.

A conventional thermal recording apparatus will be described below with reference to FIG. FIG. 14 is a configuration diagram showing a recording paper reciprocating transport mechanism of a conventional thermal recording apparatus disclosed in Japanese Patent Laid-Open No. 60-13574. In FIG. 14, reference numeral 1 denotes a thermal head, which can move to a position indicated by a broken line 1A. 2 is Y,
M and C are ink sheets sequentially coated with the heat-meltable inks, 3 is a supply roll for the ink sheet 2, and 4 is a take-up roll. Reference numeral 5 is a recording paper, 6 is a supply roll of the recording paper 5, and 7 is a thermal head 1 that connects the recording paper 5 and the ink sheet 2.
It is a platen roller that is pressed against and is driven to rotate in the direction of arrow A, and in the opposite direction, it is disengaged from the drive source by a one-way clutch or the like (not shown) and can be driven and rotated by the movement of the recording paper 5. Become. Reference numeral 8 is a pinch roller that presses the recording paper 5 against the platen roller 7, reference numeral 9 is a paper transport unit, which is movable to a position of a broken line 9A. 10
Is a guide rail that movably supports the paper transport unit 9, and 11 is a transfer wire that is connected to the paper transport unit 9 and transferred. A drive pulley 12 drives the transfer wire 11 and reciprocates the paper transport unit 9 by a pulse motor or the like (not shown). 13 and 14 are transfer wires 11
It is an intermediate pulley that is stretched around. Reference numeral 15 is rotatable around a paper holding lever provided on the paper transport unit 9 and a spindle pin 16, and holds the recording paper 5 in the holding portion 15A. Reference numeral 17 is a tension spring for urging the paper nipping lever 15 with a nipping force, and 18 is a paper nipping release lever for pushing the paper nipping lever 15 to rotate the support shaft pin 16 as a center to release the nipping of the recording paper 5. It is rotatable around the shaft pin 19. Reference numeral 20 is an electromagnetic solenoid that is driven by being connected to the paper-pinch release lever 18.

The operation of the thermal recording apparatus configured as described above will be described below. First, in the paper transport unit 9, after the paper nipping lever 15 nips the recording paper 5, the thermal head 1 is moved to the position of the broken line 1A. Next, the platen roller 7 is rotated by applying a torque in the direction of arrow A, and the sheet conveying unit 9 is moved to the position of the broken line 9A by the moving wire 11 to position the recording sheet 5 in the initial state. At this time, the recording paper 5 and the platen roller 7 can slip, and the paper transport unit 9
The recording paper 5 is not loosened between the platen roller 7 and the platen roller 7.
Next, the thermal head 1 is moved to the position indicated by the solid line 1, the ink sheet 2 and the recording paper 5 are pressed against the platen roller 7, and the drive source of the platen roller 7 is disengaged via the one-way clutch mechanism. While moving 9A to the position of the solid line 9 in the direction of arrow B, an applied pulse is applied to the thermal head 1 to generate heat, and thermal transfer recording of the first color yellow is performed. At this time, the platen roller 7 rotates following the recording paper 5 in the direction opposite to the arrow A. Next, after moving the thermal head 1 to the position of the broken line 1A, the paper transport unit 9 again moves to the position of 9A while holding the recording paper 5 and records the magenta of the second color in the same manner as the first color. To do. Further, in the same manner, the cyan recording of the third color is performed, and the electromagnetic solenoid 20 is operated while the cyan recording is completed and the paper transport unit 9 is at the solid line position, and the paper clamping lever 1 is operated.
Release 5. After that, the thermal head 1 is moved to the position of the broken line 1A, the recording paper 5 is ejected in the direction of arrow D, and the color recording process is completed.

[0005]

In the above configuration, since the roll-shaped continuous paper is used as the recording paper 5, the recording paper 5 is inserted between the paper transport unit 9 and the paper holding lever 15 from the beginning. Since the recording paper 5 does not come off between the paper conveyance unit 9 and the paper holding lever 15 even after the recording, the paper conveyance unit is driven by a pulse motor or the like to reciprocate the recording paper 5. 9, a platen roller 7 that is driven and rotated in the direction of arrow A when moving the recording paper 5 in the direction opposite to the arrow B, and a discharge roller that conveys the recording paper 5 when discharging in the direction of arrow D after recording ( It is composed of a relatively simple sheet conveying means (not shown). However, in the case of using a cut sheet-shaped recording paper which has been mainstream in recent years, after feeding the recording paper, the recording paper is conveyed to the solid line position of the paper conveyance unit 9 where the recording paper is clamped by the paper clamping lever 15, and the recording paper is held by the paper clamping lever 15. A recording sheet conveying unit to be inserted between the sheet conveying units 9 and a recording sheet to be further drawn out from between the sheet grasping lever 15 and the sheet conveying unit 9 after the recording sheet holding lever 15 is released after the recording is finished. A transport means is required. If the platen roller 7 and the pinch roller 8 are used as the recording paper conveying means, the conditions for applying the driving force to the platen roller 7 are the following four conditions.

(1) When the recording paper is conveyed between the paper holding lever 15 and the paper conveying unit 9 after the paper is fed, the paper conveying unit 9 is stopped and the platen roller 7
Is rotated in the opposite direction of arrow A.

(2) When the recording paper is conveyed during recording, the platen roller 7 is driven to rotate in the direction opposite to the arrow A.

(4) At the time of returning conveyance after recording, driving rotation in the opposite direction during recording. (3) During recording paper conveyance, in which the recording paper is pulled out from between the paper holding lever 15 and the paper conveyance unit 9, and ejected, the paper conveyance unit 9 drives and rotates the platen roller 7 in the direction of arrow A in the stopped state.

The following two means can be considered for realizing the above. (1) Between two different motors that independently drive the reciprocating conveyance of the sheet conveying unit 9 via the conveying wire 11 and the rotation of the platen roller 7, and between the platen roller 7 and the motor that drives the platen roller 7. A configuration including a bidirectionally operating clutch mechanism, in which the platen roller 7 is driven and rotated in the direction of arrow A during paper feeding and in the opposite direction during paper ejection, and is rotatable in the opposite direction of arrow A during recording (2) Reciprocal conveyance of the sheet conveying unit 9 via the conveying wire 11 and one motor for driving the rotation of the platen roller 7, a drive pulley 12 and a motor, and bidirectional movement between the platen roller 7 and the motor. And a clutch mechanism for controlling the transmission of the driving force to the paper transport unit 9 and the platen roller 7 independently. Motor or bidirectional clutch mechanism total of three existing mechanism had a disadvantageously complicated.

Further, in the above-mentioned structure, prior to the sheet clamping, the sheet clamping release lever 18 separates the sheet clamping lever 15 from the sheet conveying unit 9, and the platen roller 7 conveys the recording sheet in the B direction to form the sheet conveying unit 9. When the recording paper is inserted into the gap of the paper holding lever 15, the recording paper enters the gap between the paper transport unit 9 and the paper holding lever 15 while being pressed by the feed force from the platen roller. Therefore, if the leading edge of the recording sheet is not fixed and the position is not fixed, and the leading edge of the recording sheet is curled or the conveyance amount of the recording sheet by the platen roller 7 is excessive or insufficient, the leading edge of the recording sheet is set on the sheet holding lever 15. Therefore, there is a problem that an approach failure occurs, and the nipping width of the paper nipping is excessive or insufficient, and the nipping force is insufficient, and the nipping operation becomes unstable.

In order to solve this problem, the shape of the front end of the paper holding lever 15 is devised so that it functions as a guide when the recording paper enters, and the instability of the paper holding operation is improved.
-93273) and the like. However, since the recording paper enters while being pressed by the feed force from the platen roller while the leading end of the recording paper is in contact with the guide-shaped paper holding lever, the variation in the position of the leading end of the recording paper is slightly improved. ,
If there is frictional resistance between the leading edge of the recording paper and the paper clamping lever, and the rigidity of the recording paper is low or the curl at the leading edge is large,
There is a problem in that the recording paper does not enter well along the paper holding lever, and a bending occurs between the paper holding lever and the platen roller, and the holding operation becomes unstable.

[0012]

In order to solve the above-mentioned problems, a thermal recording apparatus according to the present invention comprises a platen roller which rotates about an axis, and a thermal recording device which presses and releases the platen roller to record on a recording sheet. Head and first and second
Reciprocatingly moving in a first predetermined range of at least the recording length with the end portion of the recording paper being sandwiched between the paper clamping members of
The first and second sheet nipping members are separated from each other, and the recording paper reciprocates in a second predetermined range in a state where the recording paper can enter and exit between the first and second sheet nipping members. A sheet conveying unit including a second sheet holding member,
A paper pinch releasing means that abuts the first or second paper pinching member to release the pinching of the recording paper, a first pulley arranged coaxially with the platen roller, the platen roller and the first platen roller. A clutch mechanism that transmits and cuts off torque between pulleys, a drive shaft that is parallel to the rotation shaft of the platen roller, and is arranged at a distance of at least the recording length, and is arranged coaxially with the drive shaft. And a belt means that is stretched between the first pulley and the second pulley and is fixed to the sheet conveying means.

[0013]

According to the present invention, when the recording paper is clamped by the above-mentioned structure, the conveyance of the recording paper is stopped at a predetermined position, and the first and second paper clamping members are separated by the paper clamping releasing means, The sheet conveying means moves in the direction of approaching the recording sheet, and the edge of the recording sheet is inserted between the first and second sheet sandwiching members to sandwich the recording sheet. Further, when releasing the nipping of the recording paper, the conveyance of the recording paper is stopped at a predetermined position, and after the paper nipping releasing means separates the first and second paper nipping members, the paper conveying means moves away from the recording paper. Then, the end of the recording paper is pulled out from between the first and second paper holding members to release the holding of the recording paper.

Further, according to the present invention, due to the above-described structure, the conveyance direction of the recording paper conveyance from the paper feed position to the paper nipping position and the conveyance direction of the recording paper from the paper nipping release position after recording to the paper ejection are the same. In the state where the thermal head presses the recording paper against the platen roller, the platen roller is moved in the opposite direction at the time of recording from the first pulley engaged with the belt means for transferring the paper conveying means via the one-way clutch. It is performed by driving and rotating and conveying the recording paper in the same direction.

By the above-mentioned two features of the present invention, the conditions for applying the driving force to the platen roller are as follows.

(1) When the recording paper is conveyed from the paper feeding position to the paper nipping position, it is driven and rotated in the opposite direction during recording.

(2) Stopping when pinching and releasing the paper. (3) During recording, driven rotation in the recording direction.

(4) At the time of returning conveyance after recording, driving rotation in the opposite direction during recording. (5) When the recording paper is conveyed from the paper pinch release position to the paper discharge, the drive rotation is in the opposite direction during recording.

That is, all that is necessary is to drive the platen roller in one direction (the opposite direction at the time of recording) to carry all the sheets in the entire printing process. The clutch mechanism can be a simple mechanism including only a motor and a one-way clutch, and a compact and inexpensive thermal recording device can be realized.

Regarding the reliability of the pinching operation and the releasing operation, the recording paper of the present invention is pinched and released in a stopped state, so that the leading edge of the recording paper is smaller than that in the conventional case (the recording paper is conveyed). The positional variation is small, and the leading edge of the recording paper does not hit the paper sandwiching member to prevent defective insertion. Further, since the recording paper is not subjected to an excessive load such as a conveying force from a roller or a frictional resistance, even if the rigidity thereof is low, the recording paper is not bent and the nipping operation is stable.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 3 are block diagrams of a thermal recording apparatus according to the present invention. FIG. 1 is a plan view, FIG. 2 is a front view, and FIG. 3 is a detailed view of a sheet conveying unit portion. In FIGS. 1 and 2, reference numeral 21 denotes a thermal head, which is movable from a solid line position 21A to a broken line position 21B. Reference numeral 22 is a sheet of heat-sensitive recording paper. Reference numeral 23 is a platen roller that presses the recording paper 22 against the thermal head 21, and 24 is a paper transport unit, which is movable from a solid line position 24A to a broken line position 24B. Reference numeral 24a is a sheet holding base provided in the sheet transport unit 24, and 24b is a sheet holding lever, which is a solid line position 24bA to a broken line position 24bB centered on the spindle pin 24c.
The recording paper 22 is clamped by the clamping unit 24d. The sheet holding lever 24b is at the broken line position 24.
In the state of bB, the contact surface 24e is the guide rail 25.
Its shape is set to be parallel to (described later). (Refer to FIG. 3) Reference numeral 24f is a torsion coil spring for urging a nipping force on the paper nipping lever 24b. Reference numeral 24g denotes a notch portion that protrudes to the right of the sheet holding base. The shape of the notch portion 24g is such that the sheet conveying unit 24 is at the position where the sheet conveying unit 24 holds the sheet when the notch portion 24g reaches the sheet passing sensor 37 (described later). Is set. The position is the position 24A. Reference numeral 25 is a guide rail that movably supports the paper transport unit 24, and is located immediately below the paper gripping lever 24b. (See Fig. 1)
Reference numeral 26 is a belt unit that is connected to the sheet transport unit 24 and is transported. Reference numeral 27 denotes a drive pulley which drives the belt means 26, which is supported by the drive shaft 28 and which transmits gears 29 and 30.
Driven by the pulse motor 31 via the, the paper transport unit 24 is reciprocated. 32 is a platen roller 23
Is a driven pulley arranged coaxially with, and is connected to the platen roller via a one-way clutch 33. As a result, the platen roller 23 is driven and rotated in the arrow E direction, and is separated from the drive source by the one-way clutch 33 in the arrow F direction, and can be driven and rotated by the movement of the recording paper 22 during recording. Reference numeral 34 denotes a sheet pinching release lever, which is rotationally moved about the spindle pin 34b from a solid line position 34A to a broken line position 34B by a separate driving means (not shown). As shown in FIG. 3, the sheet nipping release lever 34 is moved to the sheet conveying unit 2 at the broken line position 34B.
When 4 is in the range from the solid line position 24A to the broken line position 24C, the contact surface 24e of the paper holding lever 24bA is pushed to rotate the support pin 24c to the position of the broken line 24bB and release the holding of the recording paper 22. At the same time, the recording paper 22 is brought into contact with the support base 35 at the protrusion 34a.
Further, as shown in FIG. 3, the sheet nipping release lever 34B pushes the contact surface 24e in the horizontal position at the sheet nipping base 2
4a and the guide rail 25 contact vertically 2
The positional relationship is set so that it always exists within the range of points (N and O). Denoted at 37 and 38 are sheet passing sensors for detecting passage of the recording sheet 22. 39 is a paper feed roller, and the gear 40 is coaxially arranged in a rotationally fixed state. Reference numeral 41 denotes a paper feed cassette, which holds a plurality of recording papers 22 and moves to a solid line position 41A to press the recording papers 22 against a paper feed roller 39 during a paper feeding operation, and to a broken line position 41B otherwise. is there. 42 is a tension roller for applying tension to the belt means 26, 43 is an intermediate pulley,
Torque is transmitted to the paper feed roller 39 via the gear 44 and the gear 40. Paper guides 45 and 46 guide the conveyance of the recording paper 22. Reference numeral 47 denotes a stopper arranged with a minute gap in the vertical direction with respect to the guide rail 25, and prevents the guide rail 25 from bending. 48 is
A discharge tray for discharging the recording paper 22.

The operation of the thermal recording apparatus configured as described above will be described with reference to FIGS.

FIG. 4 shows an initial state of recording in the thermal recording device. The thermal head 21 is set to the position 21B, the paper transport unit 24 is set to the position 24A, the paper pinch release lever 34 is set to the position 34A, and the paper feed cassette 41 is set to the position 41B.

FIG. 5 shows a paper feeding operation state. The paper feed cassette 41B is moved to the position 41A, the recording paper 22 is pressed against the paper feed roller 39, and the pulse motor 31 is driven to drive the drive pulley 2.
When 7 is rotated in the J direction, the paper transport unit 24A is moved in the G direction, the paper feed roller 39 is rotated in the L direction, and the recording paper 22 is pulled out from the paper feed cassette 41A. The recording paper 22 further includes the paper guide 45 and the paper guide 4.
6, when the right end of the recording paper 22 passes through the space between the platen roller 23 and the thermal head 21B and reaches the paper passing sensor 38, the pulse motor 31
To stop the paper feeding operation. At this time, the driving force is not transmitted from the driven pulley 32 to the platen roller 23 by the one-way clutch 33, and the platen roller 23 is stopped. Further, the recording paper 22 transported in the H direction and the paper transport unit 24 transported in the G direction intersect below the paper guide 45 and do not collide with each other. The position 24B is set so that the right end of the recording paper 22 does not reach the paper passing sensor 38 before the paper transport unit 24 reaches the position 24B.

FIG. 6 shows a state where the recording paper is conveyed to the recording paper nip position. Move the paper feed cassette 41A to position 41B,
The thermal head 21B is moved to the position 21A, and the recording paper 2
2 is pressed against the platen roller 23. In this state, when the pulse motor 31 is driven and the drive pulley 27 is rotated in the I direction, the paper transport unit 24 is moved in the H direction, and the platen roller 23 includes the one-way clutch 3
The torque in the E direction is transmitted via 3 to rotate in the E direction, and the recording paper 22 is further conveyed in the H direction. When the left end of the recording paper 22 reaches the paper passing sensor 37, the driving of the pulse motor 31 is stopped. Here, the paper feed roller 39 rotates in the M direction, but since the paper feed cassette 41 is at the position 41B,
The recording paper 22 and the paper feed roller 39 inside the paper feed cassette 41B
Are separated from each other, and the sheet conveying force by the sheet feeding roller 39 is not generated. Further, since the diameter of the platen roller 23 is set such that the speed at which the recording paper 22 is transported by the platen roller 23 is slightly higher than the speed at which the paper transport unit 24 is transported, the paper transport unit 24 Does not catch up with the recording paper 22. Further, the paper transport unit 24 does not reach the position 24A before the left end of the recording paper 22 reaches the paper passing sensor 37.

In FIG. 7, the paper transport unit 24 is transferred,
This is an operation state in which the sheet holding lever 24b is released. The sheet pinch release lever 34A is moved to the position 34B, and the end of the recording sheet 22 is brought into contact with the support base 35 by the protrusion 34a. Next, the thermal head 21A is moved to the position 21B, and the pressure contact of the recording paper 22 with the platen roller 23 is released. In this state, the pulse motor 31 is driven to rotate the drive pulley 27 in the I direction to transfer the paper transport unit 24 in the H direction. At this time, torque in the E direction is transmitted to the platen roller 23 via the one-way clutch 33,
Although the platen roller 23 rotates in the E direction, the recording paper 22
Is not pressed against the platen roller 23, a sufficient sheet conveying force by the platen roller 23 is not generated. Further, the recording paper 22 is in contact with the platen roller 23 by its own weight, and a slight paper conveying force is applied to the recording paper 22.
Since the left end of the recording paper 22 is held by the protrusion 34a of the paper pinch release lever 34B and the support base 35, the recording paper 2
2 is not transported in the H direction. When the sheet transport unit 24 reaches the position 24C, the sheet pinch release lever 34B contacts the contact surface 24e of the sheet pinch lever 24bA, the sheet pinch lever 24bA rotates to the position 24bB, and the recording sheet 22 is held in the pinch portion 24d. There is a gap that allows you to enter. (See FIG. 3) At this time, the paper pinch release lever 3
Since the guide rail 25 is arranged immediately below the position where 4B presses the paper nipping lever 24b, the paper nipping release lever 34 presses the paper nipping base 24a so that the paper nipping base 24a does not bend. Because it is supported and its deflection is small, the paper sandwiching base 2
The positions of 4a and the sheet holding lever 24b in the height direction do not change. Further, as shown in FIG. 3, the horizontal position at which the sheet pinch release lever 34B pushes the contact surface 24e is
Since the positional relationship is set so that the paper sandwiching base 24a and the guide rail 25 always exist within the range of two points (N and O) on the left and right where the paper sandwiching base 24a and the guide rail 25 contact each other in the vertical direction, the paper sandwiching base 24a and the guide rail 25 are A couple force is not generated between them, and the paper transport unit 24 can be smoothly transported along the guide rail 25 even when pressed by the paper pinch release lever 34B. Also, the load on the pulse motor 31 at this time can be reduced. At the position 24C, there is a slight distance between the right end of the paper transport unit 24 and the left end of the recording paper 22, and the left end of the recording paper 22 does not enter the gap of the holding section 24d.

FIG. 8 shows the transfer of the paper transport unit 24,
This is an operation state in which the recording paper 22 is inserted between the paper holding lever 24bB and the paper holding base 24a. The paper transport unit 24C is moved further from the position 24C in the H direction,
When the notch portion 24g reaches the paper passing sensor 37 (position 24A), the driving of the pulse motor 31 is stopped and the transfer of the paper transport unit 24A is completed. At this time, the left end of the recording paper 22 enters the gap between the paper holding lever 24bB and the paper holding base 24a by a predetermined length, and the paper transport unit 24 comes to the optimum position for holding the recording paper 22. Here, the left end of the recording paper 22 is fixed in the vertical direction by the protrusion 34a of the paper nipping release lever 34B and the support base 35, and in the vertical direction of the paper nipping base 24a and the paper nipping lever 24bB as described above. Since the position of is also stable, the left end of the recording paper 22 is not caught or bent by the paper holding lever 24bB or the paper holding base 24a. In addition, the paper transport unit 2
4A and the recording paper 22 are both positioned in the horizontal direction by the paper passing sensor 37.
The relative positional relationship between 4A and the recording paper 22 in the horizontal direction is accurate, and there is no excess or deficiency in the amount of paper sandwiched.

FIG. 9 shows an operation state in which the paper is pinched.
By moving the paper pinch release lever 34B to the position 34A, the paper pinch lever 24bB moves to the position 24bA by the urging force of the torsion coil spring 24f, and the paper pinch lever 24b presses the recording paper 22 against the paper pinch base 24a. The pinching operation ends.

FIG. 10 shows an operation state in which recording is performed. The thermal head 21B is moved to the position 21A, and the recording paper 22
The platen roller 23 is pressure-contacted via. When the pulse motor 31 is driven and the drive pulley 27 is rotated in the J direction,
The paper transport unit 24A transports the recording paper 22 by being moved in the G direction while holding the left end of the recording paper 22. While the recording paper 22 is being conveyed, an applied pulse corresponding to an image signal is applied to the thermal head 21 to perform thermal recording on the recording paper 22. At this time, since the speed at which the platen roller 23 rotates following the conveyance of the recording paper 22 is set to be slower than the speed at which the driven pulley 32 engages with the belt means 26 and rotates, the one-way clutch 33 is activated. The torque is not transmitted from the driven pulley 32 to the platen roller 23 via the platen roller 23, and the platen roller 23 rotates following the conveyance of the recording paper 22. When the paper transport unit 24A reaches the position 24B,
The transfer of the paper transport unit 24B is stopped. At this time,
The right end of the recording paper 22 is located on the right side of the platen roller 23.

FIG. 11 shows an operation state in which the recording paper 22 is conveyed back. When the thermal head 21A is moved to the position 21B and the pulse motor 31 is driven to rotate the drive pulley 27 in the I direction, the paper transport unit 24B causes the recording paper 2 to move.
The recording paper 22 is moved in the H direction while the left end of 2 is nipped.
Is transported. When the paper transport unit 24 reaches the position 24A, the pulse motor 31 is stopped and the transport of the paper transport unit 24A is stopped. The position control of the paper transport unit 24A here is performed by counting the steps of the pulse motor 31, not by the paper passing sensor 37. At this time, torque in the E direction is transmitted to the platen roller 23 via the one-way clutch 33, the platen roller 23 rotates in the E direction, and the peripheral speed thereof is slightly higher than the conveyance speed of the recording paper 22. Therefore, platen roller 23
From the above, the sheet conveying force for feeding the recording sheet 22 faster than the conveying speed is applied to the recording sheet 22.
Since it is only in contact with the platen roller 23 due to its own weight, the pressure is weak, and the recording paper 22 is conveyed in the H direction while slipping on the surface of the platen roller 23 while being slightly tensioned.

FIG. 12 shows an operation state in which the holding of the recording paper 22 is released. The thermal head 21 is moved to the position 21A, and the platen roller 23 is pressed against the recording paper 22. Next, the paper-sheet clamping release lever 34A is rotationally moved to the position 34B, and the paper-sheet clamping lever 24bA is rotationally moved to the position 24bB. At this time, the paper holding lever 24bB and the paper holding base 24a are separated from each other, and the holding of the left end of the recording paper 22 is released. Next, the pulse motor 31 is driven to rotate the drive pulley 27 in the J direction, and the paper transport unit 24
Transfer A to position 24C. At this time, the driving force is not transmitted to the platen roller 23 by the one-way clutch 33, and the platen roller 23 is stopped while holding the recording paper 22 with the thermal head 21A. By holding the recording paper 22 by the platen roller 23 and the thermal head 21 as described above, even if the recording paper 22 is caught or attracted between the recording paper 22 and the paper nipping lever 24bB or the paper nipping base 24A, the paper is not ejected. It does not move in the G direction due to the transport unit 24. When the paper transport unit 24A reaches the position 24C, the paper transport unit 24C and the recording paper 22 are completely separated in the horizontal direction as described above.

FIG. 13 shows an operation state in which the recording paper 22 is discharged and conveyed. The paper pinch release lever 34B is rotationally moved to the position 34A, and the paper pinch lever 24bB is rotationally moved to the position 24bA. In this state, when the pulse motor 31 is driven and the drive pulley 27 is rotated in the I direction, the paper transport unit 24C is moved in the H direction, and the platen roller 23 is transferred to the platen roller 23 via the one-way clutch 33 in the E direction. Is transmitted in the E direction, the recording paper 22 is conveyed in the H direction by the rotation of the platen roller 23, and drops onto the paper discharge tray 48. Paper transport unit 24C is at position 24
At the time of reaching A, the driving of the pulse motor 31 is stopped,
The transfer of the paper transport unit 24A is stopped, all the steps of printing are completed, and the initial state for the next printing is set.

Table 1 shows a list of the state of the mechanism, the recording paper conveyance direction, and the recording paper conveyance means in the series of printing operation steps of this embodiment.

[0035]

[Table 1]

As is clear from this (Table 1), the thermal recording apparatus of the present invention uses one pulse motor for the recording paper conveyance in the entire printing process, using the paper conveyance unit, the platen roller and the paper feed roller as the conveyance means. Drive (the platen roller is driven via a one-way clutch).

As described above, according to this embodiment, the platen roller 23, the thermal head 21 pressed against and released from the platen roller 23, the edge of the recording sheet 22 between the sheet pinching lever 24b and the sheet pinching base 24a. The sheet holding lever 24b and the sheet holding base 24a are separated from each other by reciprocating between the positions 24A and 24B while holding the portions between the positions 24A and 24C with the recording paper 22 being able to enter and leave between them. A paper transport unit 24 that reciprocates in the range, a paper pinch release means 34 that abuts the paper pinch lever 24b to release the pinch of the recording paper 22, and a driven pulley 32 that is arranged coaxially with the rotation axis of the platen roller 23. , A one-way clutch 33 that transmits and blocks torque between the platen roller 23 and the driven pulley 32,
By providing the belt means which is stretched between the drive pulley 27 and the driven pulley 32 and fixed to the paper transport unit 24, the recording paper is transported from the paper feeding position to the paper nipping position 24A and the paper after the recording is completed. When the thermal head 21A presses the recording paper 22 against the platen roller 23, the recording paper is conveyed from the pinch release position 24A to the discharged paper from the driven pulley 32 engaged with the belt means 26 for transferring the paper conveyance unit 24. This can be performed by driving and rotating the platen roller 23 in the E direction via the one-way clutch 33 to convey the recording paper in the H direction.

When the recording paper 22 is clamped, the conveyance of the recording paper 22 is stopped at the position 24A, and the paper clamp release lever 34 separates the paper clamp lever 24b from the paper clamp base 24a. Unit 24
Is moved in the H direction, the end of the recording paper 22 is inserted between the paper holding lever 24b and the paper holding base 24a to hold the recording paper 22, and when the holding of the recording paper 22 is released, the recording paper 22 is similarly conveyed. After stopping at the position 24A and separating the paper holding lever 24b and the paper holding base 24a by the paper holding release lever 34, the paper carrying unit 24 moves in the G direction, and recording is performed from between the paper holding lever 24b and the paper holding base 24a. The end portion of the paper 22 can be pulled out to release the sandwiching. That is, the recording paper 22 is not conveyed during the pinching and releasing operations.

Due to the above-mentioned two features of the present invention, the driving force can be applied to the platen roller 23 only in the E direction during the entire printing process, and thus the paper transport unit 2
4 and the platen roller 23 and the paper feed roller 39 are driven by one pulse motor as a conveyance means (the platen roller is driven in the E direction through a one-way clutch), so that all the sheets are conveyed in the entire printing process. Therefore, the motor and the bidirectional clutch mechanism, which conventionally required a total of three, can be a simple mechanism including only the motor and the one-way clutch, and a small-sized and inexpensive thermal recording device can be realized.

Regarding the reliability of the recording paper pinching operation,
Conventionally, the recording paper 22 of this embodiment is clamped and released while it is stopped (the recording paper is transported).
Compared with this, the variation in the position of the tip is small, and the tip does not hit the sheet holding lever 24b or the sheet holding base 24a, so that the insertion failure or the like does not occur. Further, since the recording paper 22 is not subjected to an extra load such as a conveying force from a roller or a frictional resistance, the recording paper 22 does not bend even when its rigidity is low, and the holding operation is stable.

Further, in this embodiment, the paper holding lever 24
b is the position 24b pressed by the paper-pinch release lever 34B
In the state of B, the shape is set so that the contact surface 24e is parallel to the guide rail 25. Therefore, even if the sheet conveying unit 24 is moved in this state, the angular position of the sheet holding lever 24b changes. Therefore, the recording paper 22 can be stably held and released.

Further, in this embodiment, the paper holding lever 24
When the paper conveyance unit 24A is moved from the position 24A to the position 24C while the paper b is separated from the paper nipping base 24a and the paper nipping is released, the paper 22 is pushed by the thermal head 21 and the platen roller 23. Holds by pressure. By strongly holding the recording paper 22 by the platen roller 23 and the thermal head 21 in this manner, the recording paper 22 and the paper holding lever 24bB
Even if the recording paper 22 is caught or sucked between the paper holding bases 24A, the recording paper 22 is not moved by the paper transport unit 24 in the G direction and is stable.
The pinching of can be released.

Further, in the present embodiment, the paper pinch release lever 34 is provided with a protrusion 34a, and when the paper pinch release lever 34 presses the paper pinch lever 24b, the protrusion 34 is simultaneously pressed.
Since a has a configuration in which the end portion of the recording paper 22 is pressed against the support base 35, the recording paper 22 is fixed in the vertical direction, and the left end of the recording paper 22 is attached to the paper holding lever 24bB or the paper holding base 24a. It is not caught or bent, and the reliability of the pinching operation is improved.

Further, in this embodiment, the paper transport unit 2
4, at the position 24C, the sheet pinch release lever 34B contacts the contact surface 24e of the sheet pinch lever 24bA, and the sheet pinch lever 24bA is rotated to the position 24bB.
Since the guide rail 25 is arranged immediately below the position where the paper-sheet clamping release lever 34B presses the paper-sheet clamping lever 24b, the paper-sheet clamping base 24a does not bend due to the pressing of the paper-sheet clamping release lever 34, and the guide rail 2
5 is also supported by a stopper 47 arranged with a minute gap in the vertical direction, and since its deflection is small,
Even when pressed by the sheet pinch release lever 34B, the positions of the sheet pinch base 24a and the sheet pinch lever 24b in the height direction do not change, and the reliability of the pinching operation can be improved. In addition, the paper sandwiching base 24a can be made thin and the guide rail 25 can be made small in diameter, and the device can be made thin and lightweight.

Further, in the present embodiment, the horizontal position at which the sheet pinch release lever 34B pushes the contact surface 24e is in the range of two points N and O on the left and right where the sheet pinch base 24a and the guide rail 25 make vertical contact. Since the positional relationship is set so as to always exist inside, the couple is not generated between the paper sandwiching base 24a and the guide rail 25, and the paper transport unit 2 is pressed even when pressed by the paper sandwiching release lever 34B.
4 can be smoothly transferred along the guide rail 25. Also, the load on the pulse motor 31 at this time can be reduced.

Further, in this embodiment, the paper transport unit 2
4 is provided with a notch portion 24g whose shape is set so that the paper transport unit 24 comes to a position for nipping the paper when the leading edge reaches the paper passing sensor 37, and both the paper transport unit 24A and the recording paper 22 are provided. Paper passing sensor 3
Since the positioning is performed by 7, the relative positional relationship between the two in the horizontal direction is accurate, and the paper sandwiching amount does not become excessive or deficient, and a stable sandwiching operation can be performed.

Further, in this embodiment, when the paper pinch release lever 34 is at the position 34B, the paper pinch release lever 34 is
The height shape of the paper transport unit 24 is set so that B only contacts the contact surface 24e of the paper gripping lever 24b (does not contact the portion other than the contact surface 24e of the paper transport unit 24). Therefore, even if the paper transport unit 24 exists in a position other than the range from 24A to 24C, the paper pinch release lever 34 does not crush the paper transport unit 24 or lock the paper pinch release lever 34. Absent. Therefore, it is possible to initialize (move to the initial state) the sheet pinch release lever 34 regardless of the position of the sheet transport unit 24.

In this embodiment, the recording paper 22 is a thermosensitive recording paper that develops a single color, and its operation has been described.
The recording operation shown in FIG. 10 and the recording operation shown in FIG. 11 are carried out by using a multicolor heat-sensitive recording material having three kinds of heat-sensitive layers that develop different colors of Y, M and C shown in JP-A-4-28585. Multicolor recording can be performed by repeating the returning and conveying operation three times in sequence.

Further, in the present embodiment, the one-way clutch 33
However, an electromagnetic clutch or the like may be used.

Further, in this embodiment, the paper holding lever 24
When the paper b is moved to carry out the paper nipping (FIG. 7), the paper nipping release lever 34 is moved to the position 34B and then the paper carrying unit 24 is moved to the position 24C. The sheet pinch release lever 34 may be moved to the position 34B after being transported to and temporarily stopped.

[0051]

As described above, according to the present invention, the end portion of the recording paper is sandwiched between the platen roller, the thermal head that is pressed against and released from the platen roller, and the first and second sheet sandwiching members. And reciprocate in a first predetermined range of at least the recording length to separate the first and second sheet holding members from each other, and the second predetermined range in a state where the recording sheet can enter and leave between them. Paper conveying means having first and second paper nipping members for reciprocating, paper nipping releasing means for abutting the first or second paper nipping member to cancel nipping of recording paper, and a platen roller coaxial with Is equipped with a first pulley arranged in the above and a clutch mechanism for transmitting and blocking torque between the platen roller and the first pulley, thereby simplifying the sheet conveying means and the drive system, and being small and inexpensive. Was Recording device can be realized, also in which excellent thermal recording apparatus capable of improving reliability increased operation stability of the recording sheet pinching and releasing can be realized.

[Brief description of drawings]

FIG. 1 is a plan view of a thermal recording device according to an embodiment of the present invention.

FIG. 2 is a front view of the thermal recording apparatus according to the embodiment of the present invention.

FIG. 3 is a detailed view of a sheet conveying unit of the thermal recording apparatus according to the embodiment of the invention.

FIG. 4 is an operation explanatory diagram of the thermal recording apparatus in the embodiment of the present invention.

FIG. 5 is an operation explanatory diagram of the thermal recording apparatus in the embodiment of the present invention.

FIG. 6 is an operation explanatory diagram of the thermal recording apparatus according to the embodiment of the present invention.

FIG. 7 is an operation explanatory diagram of the thermal recording apparatus in the embodiment of the present invention.

FIG. 8 is an operation explanatory diagram of the thermal recording apparatus in the embodiment of the present invention.

FIG. 9 is an operation explanatory diagram of the thermal recording apparatus in the embodiment of the present invention.

FIG. 10 is an operation explanatory diagram of the thermal recording apparatus in the embodiment of the present invention.

FIG. 11 is an operation explanatory diagram of the thermal recording apparatus in the embodiment of the present invention.

FIG. 12 is an operation explanatory diagram of the thermal recording apparatus according to the embodiment of the present invention.

FIG. 13 is an operation explanatory diagram of the thermal recording apparatus in the embodiment of the present invention.

FIG. 14 is a side view of a conventional thermal recording device.

[Explanation of symbols]

 21 Thermal Head 22 Recording Paper 23 Platen Roller 24 Paper Conveying Unit 25 Guide Rail 26 Belt Means 27 Drive Pulley 28 Drive Shaft 32 Driven Pulley 33 One-way Clutch 34 Paper Clamp Release Lever 35 Support Stand 47 Stopper

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hitoshi Nishitani Hitoshi Nishitani 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Zenichi Nomura 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. (72) Inventor Fumihiro Ito 1006, Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor, Osamu Osamu, 1006 Kadoma, Kadoma City, Osaka Prefecture

Claims (10)

[Claims] 1. A platen roller that rotates about an axis, a thermal head that presses and releases the platen roller to record on a recording sheet, and an end portion of the recording sheet between the first and second sheet nipping members. In a state where the recording paper is sandwiched, the recording paper is reciprocated in a first predetermined range of at least the recording length to separate the first and second paper sandwiching members, and the recording paper is the first paper.
And a sheet conveying unit including the first and second sheet sandwiching members that reciprocate in a second predetermined range in a state where the sheet can be moved in and out between the second sheet sandwiching member, and the sheet conveying unit is A paper pinch releasing means for abutting the first or second paper pinching member to release the pinching of the recording paper when it exists within the second predetermined range, and a first pinch arranged coaxially with the platen roller. A pulley, a clutch mechanism that transmits and blocks torque between the platen roller and the first pulley, and a rotation axis of the platen roller are parallel to each other, and are arranged at a distance of at least a recording length or more. A drive shaft; a second pulley arranged coaxially with the drive shaft; and belt means stretched between the first pulley and the second pulley and fixed to the sheet conveying means. Features and That heat the recording device. 2. The thermal recording apparatus according to claim 1, wherein the clutch mechanism comprises a one-way clutch for driving and rotating the platen roller in a direction opposite to that during recording. 3. The first and second sheet nips when the paper conveying means moves in a second predetermined range with the paper nipping releasing means in contact with the first or second paper nipping member. The thermal recording apparatus according to claim 1, wherein the angle of the member does not change. 4. A platen roller that rotates about an axis, a thermal head that presses and releases the platen roller to record on a recording sheet, and an end portion of the recording sheet between the first and second sheet nipping members. In a state where the recording paper is sandwiched, the recording paper is reciprocated in a first predetermined range of at least the recording length to separate the first and second paper sandwiching members, and the recording paper is the first paper.
And a sheet conveying unit including the first and second sheet sandwiching members that reciprocate in a second predetermined range in a state where the sheet can be moved in and out between the second sheet sandwiching member, and the sheet conveying unit is A sheet pinch releasing means for releasing the pinch of the recording sheet by coming into contact with the first or second sheet pinching member when it exists within the second predetermined range, the thermal head includes the recording sheet on the platen roller. The sheet conveying means is pressed, and the sheet nipping release means contacts the first or second sheet nipping member to separate the first and second sheet nipping members from each other, and the paper conveying means sets the second predetermined range. The thermal recording apparatus is characterized in that the recording paper moves out of the gap between the first and second paper holding members. 5. The first and second sheet nipping members are reciprocally moved in a first predetermined range of at least the recording length in a state where the end portion of the recording paper is nipped between the first and second sheet nipping members. The paper holding member is separated, and the recording paper is set to the first and second recording papers.
Between the paper sandwiching members of the second
Sheet conveying means including the first and second sheet sandwiching members that reciprocate within a predetermined range, and the first or second sheet when the sheet conveying means is within the second predetermined range. A thermal recording apparatus comprising a sheet pinching release means for abutting a pinching member to release the pinching of the recording sheet and a part of which abuts the recording sheet. 6. The first and second sheets which reciprocate in a first predetermined range of at least the recording length in a state where an end portion of the recording sheet is sandwiched between first and second sheet sandwiching members. Paper transporting means having a holding member, and the first or second
A sheet pinching releasing means for abutting the sheet pinching member to release the pinching of the recording sheet, and the sheet pinching releasing means are arranged substantially directly below a position where the first or second sheet pinching member abuts, A thermal recording device comprising a guide rail for guiding the reciprocating motion of the conveying means. 7. The heat according to claim 6, further comprising a stopper arranged below the guide rail with a minute gap in a direction perpendicular to the guide rail to prevent the guide rail from bending. Recording device. 8. The first and second sheet nipping members are reciprocally moved in a first predetermined range of at least the recording length with an end portion of the recording paper being nipped between the first and second paper nipping members. The paper holding member is separated, and the recording paper is set to the first and second recording papers.
Between the paper sandwiching members of the second
Sheet conveying means including the first and second sheet sandwiching members that reciprocate within a predetermined range, and the first or second sheet when the sheet conveying means is within the second predetermined range. A sheet pinch releasing means for contacting a pinching member to release the pinching of the recording sheet, and a guide rail for guiding the reciprocating motion of the sheet conveying means, wherein the sheet pinch releasing means is the first or second sheet pinch member. The thermal recording apparatus characterized in that the position of the sheet conveying means in contact with the sheet conveying means always exists within a range in which the sheet conveying means contacts the guide rail in the vertical direction. 9. A first predetermined range of at least the recording length is reciprocated in a state where an end portion of a recording sheet is sandwiched between first and second sheet sandwiching members, and the first and second sheet clamping members are reciprocally moved. The paper holding member is separated, and the recording paper is set to the first and second recording papers.
Between the paper sandwiching members of the second
Both the paper conveyance means including the first and second paper holding members that reciprocate within a predetermined range, the position detection in the conveyance direction of the recording paper, and the position detection in the conveyance direction of the paper conveyance means are performed. A thermal recording device comprising a sensor. 10. The first and second sheet nipping members are reciprocally moved in a first predetermined range of at least the recording length in a state where an end portion of the recording paper is nipping between the first and second paper nipping members. The first and second sheet sandwiching members that move apart the sheet sandwiching member and reciprocate in a second predetermined range in a state where the recording sheet can enter and leave between the first and second sheet sandwiching members. And a first sheet feeding means provided when the sheet feeding means is within the second predetermined range.
Alternatively, when the recording paper is unpinched by coming into contact with a predetermined contact portion of the second paper nipping member, and the paper conveying means is outside the second predetermined range, the first or second paper nipping A thermal recording apparatus comprising a sheet pinching release means that does not contact any part other than a predetermined contact part of the member.