JPH01165472A - Thermal transfer type printer - Google Patents

Abstract

PURPOSE:To contrive a reduction in the diameter of a platen roller and simplification of a clamping mechanism, by providing a clamp lever for clamping both end parts of a printing paper, and a clamp-releasing part for separating the clamp lever from a support member at the time of a paper-supplying mode and a paper-discharging mode. CONSTITUTION:A support member 42 comprises a flat clamp part 42a for clamping a printing paper 25 and a bent part 42b for facilitating insertion of the paper 25 at the tip of the clamp part 42a. A clamp lever 45 is turnably supported on a shaft 40b, and is energized for turning counterclockwise by a spring force of a tortion spring 47. With a shaft 24 rotated clockwise at the time of a paper-supplying mode, a spring force of a spring 49 is exerted on a guide arm 23 due to the turning of an arm 48, whereby the guide arm 23 is turned clockwise from a lowered position, and an extended part 23d is brought into contact with a pin 45b on the clamp lever 45 protruding from a through-hole 40d in a ring 40. Therefore, the clamp lever 45 is turned clockwise, and the clamp part 45a is separated from the clamp part 42a of the support member 42.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a thermal transfer printer, and more particularly to a thermal transfer printer configured to further simplify a platen roller and a clamp mechanism for clamping printing paper.

2. Description of the Related Art A conventional thermal transfer printer is shown in FIG. 22, for example. In FIG. 22, printing paper 2 supplied to the outer periphery of platen roller 1 is clamped by clamper 3 and wound around platen roller 1, which rotates counterclockwise. The thermal head 5 rotates the ink film 4 which is wound up in the direction of the arrow as the platen roller 1 rotates.
is pressed against the printing paper 2. Further, a drive signal is supplied to the thermal head 5 in accordance with the rotational position of the platen roller 1, and the heat from the heating element 6 causes the meltable ink or sublimable ink of the ink film 4 to be transferred onto the printing paper 2.

Problems to be Solved by the Invention However, in the conventional thermal transfer printer described above, the printing paper 2 fed to the platen roller 1 is clamped by a clamper 3 that presses the platen roller 1 from the outside. A clamp mechanism (not shown) is provided inside the platen roller 1 to move the clamper 3 to a clamp position or a clamp release position. Therefore,
In the above printers, it is difficult to reduce the diameter of the platen roller 1, and the outer diameter of the platen roller 1 tends to increase.If the outer diameter of the platen roller is increased, the pressing force of the heating element of the thermal head will decrease. The image quality deteriorates.■ As the platen roller becomes larger, the pressure on the thermal head must be increased, which leads to an increase in printer size and rigidity, which increases weight and manufacturing costs.■Furthermore, Increasing the pressing force of the thermal head requires increasing the size of the drive source for the platen roller, resulting in problems such as difficulty in controlling the platen roller.

Therefore, an object of the present invention is to provide a thermal transfer printer that solves the above problems.

Means and Effects for Solving the Problems The present invention provides the above-mentioned thermal transfer printer, including support members provided at both ends of the platen roller, and a support member mounted between the support members so as to extend in the longitudinal direction of the platen roller. A holding member on which the leading edge of the fed printing paper is placed, a clamp lever supported by the supporting member and clamping both ends of the printing paper placed on the holding member, and a clamp lever in paper feeding mode and paper ejection mode. The clamp lever is provided with a clamp release part that separates the clamp lever from the holding member, thereby reducing the diameter of the platen roller and simplifying the clamp mechanism.

Embodiment FIGS. 1 to 7 show an embodiment of a thermal transfer printer according to the present invention.

In FIG. 1, a holder 13 for holding the thermal head 12 is provided above the platen roller 11, and the holder 13' is rotatably supported by a shaft 14. As will be described later, the holder 13 is rotated clockwise by driving an actuator (not shown), thereby lowering the thermal head 12 to a position where it presses the platen roller 11.

An ink film 15 (yellow, cyan) is placed between the platen roller 11 and the thermal head 12.

Four color frames (magenta and black) are mounted in sequence. The ink film 15 is wound around the supply reel 16 and the guide balls 178 to 17
G and is guided by the row 513a provided on the holder 13 and wound onto the take-up reel 18.

A tension ball 19 presses the ink film 15 to apply tension to prevent the ink film 15 from loosening.

A pinch roller 20 is rotatably supported at the tip of the lever 21. 22 +, t guide rollers rotatably supported by the guide arm 23.

Also, lever 21. Both guide arms 23 are rotatably supported by a shaft 24.

Reference numeral 25 denotes printing paper, which is placed on a tray 26 (having a slope 26a for paper feeding) and held by an L-shaped presser claw 27. 28 is a paper feed roller, and the platen roller 11
When supplying the printing paper 25 to the tray 26, the tray 26 is rotated and lowered to transport the printing paper 25 placed on the tray 26 to the left in the figure.

Reference numerals 29, 30, and 31 denote guide plates that form a paper feed passage 32 between guide plates 29 and 30, and a paper discharge passage 33 between guide plates 30 and 31.

34 and 35 are in the paper ejection row, counterclockwise.

It rotates clockwise and transports the printed printing paper 25 passing through the paper discharge path 33 as described later.

Reference numeral 56 denotes a reflection type optical sensor υ, and 57 a reflection plate, which are disposed so as to face each other with the color film 15 interposed therebetween. This optical sensor 56 detects the number of opaque parts and transparent parts (not shown) provided on the upper side edge of the ink film 15. Since the ink film 15 is sequentially provided with four color frames of yellow, cyan, magenta, and black, the optical sensor 56 detects the number of opaque parts and transparent parts that differ for each color frame to identify each color. Generate a signal for

Next, the detailed configuration around the platen roller 1 will be explained in the second section.
This will be explained with reference to FIGS. 7 to 7.

As shown in FIG. 2, the platen roller 11 has a rubber elastic body attached to its outer periphery, and has shafts 11a+ at both ends. The shafts 11a at both ends are supported by bearings 37 held on the side wall 36 of the printer. Also, one shaft 11
An encoder 38 for detecting the rotational phase of the platen roller 11 is installed at a.

This encoder 38 outputs one reference pulse (PG(Z
) pulse) and outputs 1500 continuous pulses (FG pulses) indicating the rotational position of the platen roller 11.

Further, the other shaft 11a is connected to a drive mechanism (not shown) such as a platen roller motor.

In FIG. 2, 60 is a cam plate which is displaced in the direction of arrow X by the drive of a motor (not shown), so as to move the lever 21° which supports the pinch roller 20 and the guide roller 22 and the guide arm 23 backward. Rotate and displace. The displacement position of the cam plate 60 is detected by three cam sensors (not shown) made up of optical sensors, and the detection signals are supplied to the motor to control the rotation angle of the motor.

A ring 40 having a clamp mechanism 39 is provided at both ends of the platen roller 11, and the ring 40 is attached to the shaft 11a.
It is loosely fitted. Since the clamp mechanisms 39 at both ends of the platen roller 11 have the same configuration, only one side shown in FIGS. 2 to 4 will be described.

A clutch ring 41 is fitted and fixed to the shaft 11a, and a recess 41a is formed on the outer periphery of the clutch ring 41. The ring 40 is provided outside the clutch ring 41. A holding member 42 having an angular cross section and extending in the longitudinal direction of the platen roller 11 is screwed to the rings 40 at both ends with screws 43 . As will be described later, the holding member 42 includes a flat clamp portion 42a that clamps the printing paper 25, and a clamp portion 42a that clamps the printing paper 25 at the tip of the clamp portion 42a.
It has a bent portion 42b that facilitates the insertion of 5.

Further, on the inner surface of the ring 40 is a shaft 40a that supports a clutch lever 44 and a clamp lever 45.

40b protrudes, and a recess 4 is formed on the outer periphery of the ring 40.
0C is provided. Furthermore, the ring 40 has a square hole 40d and a central hole 40e into which the shaft 11a is fitted.
! It is set up.

The clutch lever 44 has a protrusion 44a at one end that engages with the recess 41a of the clutch ring 41, and together with the clutch ring 41 constitutes a clutch HM41'. Further, the clutch lever 44 has a concave portion 40c1 of the ring 40 at the other end.
l: Has a pin 44b to be fitted. Also, the clutch lever
At the center of 44 is a hole 44 into which the shaft 40a of the ring 40 is fitted.
The clutch lever 40 is rotatably supported by a shaft 40a and biased clockwise by the elastic force of a torsion spring 46 (shown in FIG. 3).

The clamp lever 45 is a clamp 1428 of the holding member 42.
The clamp portion 45a that comes into contact with the ring 40 and the tribute hole 4 of the ring 40
0d, and a hole 45c into which the shaft 40b of the ring 40 is fitted. Also, clamp lever 45
is rotatably supported on a shaft 40b, and is biased to rotate counterclockwise by a bullet 1 horn of a torsion spring 47 (shown in FIG. 3).

As shown in FIGS. 3 and 5, the guide arm 23 includes a flat plate part 23a that guides the printing paper 25, and side plate parts 23b arranged on both sides of the flat plate part 23a.
The guide roller 22 is supported between the rollers 3b. Further, the guide arm 23 is provided with a first assembly sensor 58 and a second paper sensor 59 (consisting of light emitting elements 58a, 59a and light receiving elements 58b, 59b, respectively), which will be described later. Note that the front edge of the flat plate portion 23a is bent downward to facilitate transportation of the printing paper 25. Further, a hole 23c that fits into the side plate 23b is formed with a diameter of 1 m 24, and the end thereof is an extension 23d inclined at a predetermined angle. An arm 48 (shown in FIG. 3) is fixed to the fd 124, and a coil spring 49 is disposed between the arm 48 and the flat plate portion 23a of the guide arm 23. Therefore, as shown in Figure 7,
When the @24 rotates in the h1 direction in the paper feeding mode, the elastic force of the spring 49 due to the rotation of the arm 48 acts on the guide arm 23, and the guide arm 23 descends as shown by the two-dot chain line in FIG. A clamp lever 45 that rotates clockwise from the position and has an extending portion 23d protruding from the through hole 40d of the ring 40.
The pin 45b contacts the pin 45b.

Therefore, the clamp lever 45 rotates clockwise so that the clamp part 4.5a is moved to the clamp part 42a of the holding member 42.
be further apart.

As shown in FIG. 6, the width dimension of the printing paper 25 is longer than the total length L1 of the platen roller 11 and shorter than the position (dimension L2) of the inner wall of the ring 40.

Therefore, the printing paper 2 transferred to platen 0-511
Both ends of the distal end of the guide arm 23 are inserted between the clamp part 42a of the holding member 42 and the clamp part 45a of the clamp lever 45, which are spaced apart from each other and are open, to prevent the guide arm 23 from rotating in the counterclockwise direction. It is clamped together.

The lever 21 rotatably supports the pinch roller 20.
It has a hole 21a into which the phase 24 fits at the lower end, and a hole 21b into which the shaft 20a of the pinch roller 2o fits into the upper end. 51
il* is a release member that releases the coupling between the clutch lever 44 and the clutch ring 41;
21c, and has a roller 51a at the tip. 5
Reference numeral 2 denotes a coil spring, one end of which is hooked to a hook portion 21d of the lever 21, and the other end of which is hooked to a protrusion portion 51b of the release member 51. Therefore, the release member 51 is urged to rotate in the counterclockwise direction by the tensile force of the spring 52, and when the lever 21 rotates counterclockwise, the row 551a comes into contact with the outer periphery of the ring 40.

Further, a spring 54 is interposed between the lever 21 and an arm portion 53a of an arm 53 supported on the shaft 24. The arm 53 is in a position not shown by the two-dot chain line in FIG. 3, and when the lever 55 is driven clockwise as described later, the lever 5
It is pressed by the roller 55a of No. 5 and rotates to the position shown by the solid line. The rotation of the arm 53 is transmitted to the lever 21 via the elastic force of the coil spring 54, which causes the lever 21 to rotate counterclockwise and move the pinch row 520 toward the platen roller 1.
1.

Next, the operation of the thermal transfer printer configured as described above will be explained for each mode.

■Reset mode FIG. 1 shows the above printer in a standby state, with the thermal head 12. Pinch roller 20. The guide roller 22 is spaced apart from the platen row 511.

This is a platen roller 11 made of an elastic rubber material or the like. Pinch roller 20. This is to prevent the guide roller 22 from being deformed.

When printing is performed in this standby state, as shown in the time chart of Fig. 8, the mode first goes into reset mode, and as shown in (h) in Fig. 8, the platen motor (
(not shown) is started and rotates the platen row 511 in the o'clock direction. When the platen row 511 rotates more than once, the protrusion 44a of the clutch lever 44 is pushed into the recess 4 of the clutch ring 41 by the pressing force of the torsion spring 46.
1a, platen roller 11 and clamp tEHM
39 (consisting of a clamp lever 45 and a holding member 42) is coupled to the ring 40, and the ring 40 rotates together with the platen roller 11. As the platen roller 11 rotates, the encoder 38 generates a reference pulse (Fig. 8(i)
) are output, and the continuous pulse is 375 pulses (
As shown in Figure 8 (j), however, 375 pulses have a rotation angle of 90'.
(equivalent to ) is counted, the platen motor stops.

(2) Paper feeding mode Next, the shaft 55b of the lever 55 is rotated clockwise to rotate the arm 53 counterclockwise.

As a result, the lever 21 supporting the pinch [1-ra 2o]
are rotated in the same direction while being pressed by the spring 54, and the pin roller 2o is pressed against the platen roller 11 as shown in FIG. In addition, as the lever 21 rotates, the lever 2
The release member 51 supported by the ring 40 also rotates in the same direction, and the roller 51a comes into sliding contact with the outer periphery of the ring 40.

At the same time, the shaft 24 is rotated counterclockwise, and the guide 7
- Rotate the arm 23 in the same direction. Therefore, the guide roller 22 supported by the guide arm 23 is pressed against the platen roller 11, and the extending portion 23d comes into contact with the pin 45b of the clamp lever 45, thereby separating the clamper portion 45a from the holding member 42.

Furthermore, as shown in FIG. 8(d), the paper feed roller 28 is rotated clockwise by activation of the reel motor and paper feed/discharge motor (not shown), and the paper feed roller 28 is lowered to remove the printing paper 25 on the tray 26. The printing paper 25 is moved in the direction of arrow B in FIG. 9 by the frictional force of the paper feed roller 28. Incidentally, since the leading end of the printing paper 25 is held down by the presser pawl 27, the printing paper 25 pressed against the paper feed roller 28 will be bent as shown by "A" in FIG.

Therefore, the presser pawl 27 cannot fully press down the printing paper 25, and the leading edge of the print sheet 25 is released from the presser pawl 27 and transferred to the slope 26a of the tray 26. In this way, one sheet of printing paper 25 is sent to the paper feed path 32, and the guide plate 29
．． The flat plate portion 2 of the guide 7-m 23 is guided by the guide 7-30.
3a, the optical path of the first information sensor 58 made up of a light emitting element 58a and a light emitting element 58b is blocked by the printing paper 25. At this time, the first paper sensor 58
A paper detection signal "k1" is output as shown in Figure (k).

When the first paper sensor 58 detects the printing paper 25, the platen motor is started again, and the printing paper 25 is inserted between the holding member 42 and the clamp lever 45 by the platen roller 11 and the guide roller 22, and is held. It comes into contact with the member 42 and stops. The platen motor stops when 50 consecutive pulses ("j2" in FIG. 8, corresponding to a rotation angle of 12 degrees) are counted.

Incidentally, when the platen roller 11 is rotating, the clutch lever 44 is not engaged with the clutch ring 41, and the clamp mechanism 39 is stopped.

Thereafter, as shown in FIG. 1, the lever 21 is rotated clockwise and the guide arm 23 is rotated counterclockwise to separate the pinch roller 2o and the guide roller 22 from the platen roller 11. As a result, the clamp lever 45
rotates counterclockwise by the elastic force of the traction spring 47, presses the clamp portion 45a against the holding member 42, and presses the printing paper 25 placed on the clamp portion 42a of the holding member 42.
Clamp both sides of the tip. Although the printing paper 25 is clamped only at both ends thereof, the printing paper 25 does not bend after being clamped because it is placed in contact with the holding member 42 which is longer than the entire length of the platen roller 11.

Next, by starting the reel motor/paper supply/discharge motor (rd2J in FIG. 8), the paper feed 0-ra 28 is separated from the backside printing paper 25.

Thereafter, the platen roller 11 is rotated clockwise (rh3J in FIG. 8), and the protrusion 44a of the clutch lever 44 of the clamp mechanism 41' is rotated into the recess 41 of the clutch ring 41.
engage a.

When the clutch lever 44 is engaged with the clutch ring 41, the platen roller 11 is rotated until 375 consecutive pulses (corresponding to a rotation angle of 90') are applied to the run 1 after the reference pulse is output. This is because the concave portion 41a of the clutch ring 41 is in advance of the position of the protrusion 45a of the clamp lever 45 by transferring the printing paper 25 to the holding member 42 by the rotation 0J of the platen roller 11 as described above. be.

Next, as shown in FIG. 10, 50 continuous pulses (
The platen roller 11 is rotated until the rotation angle (corresponding to a rotation angle of 12°) is counted. Then, the pinch roller 20 and the guide roller 22 are pressed against the platen roller 11 again.

In this state, as mentioned above, the platen roller 11 is
Since the clamp lever 45 has moved 0 times, the clamp lever 45 is
5 is deviated from 16 when clamped, and there is no risk that the bin 45b will not come into contact with the extending portion 23d of the guide arm 23 and the clamp will be released.

Further, the platen roller 11 is connected to the pinch roller 20. When the guide a-ra 22 is rotated clockwise while being pressed (
In FIG. 8, the clamp mechanism 39 also rotates integrally to wrap the printing paper 25'' around the outer periphery of the platen D-511, but as shown in FIG.
1a fits into the recess 40c of the ring 40 and presses the pin 44b of the clutch lever 44. As a result, the clutch lever 44 rotates counterclockwise against the pressing force of the spring 46, and is disengaged from the clutch ring 41. As a result, the ring 40. Clamp lever 45, holding member 42
stops, but the platen roller 11 continues to rotate.

As shown in FIG. 11, although the leading edge of the printing paper 25 is clamped and stopped as described above, the printing paper 25 passes between the platen roller 11 and the guide roller 22 due to the rotation of the platen roller 511. It is transferred to the left in the figure. Therefore, the printing paper 25 continues to be fed onto the platen roller 11 in a largely swollen state.

Furthermore, as the platen roller 11 rotates as shown in FIG.
．． Light emitting element 58a of first paper sensor 58 and light emitting element 58
It passes between b. The first paper sensor 58 is connected to the printing paper 2
5, the detection signal rk2J (shown in FIG. 8(k)) is output, and after outputting the reference pulse (1o), 37
Count 5 and stop the platen motor.

(2) Heading Mode After this, the take-up reel 18 of the ink film 15 is rotated clockwise by the rotational drive (rdzJ in FIG. 8) of a reel motor (not shown). Ink film 15
yellow, cyan.

Four color frames of magenta and black are successively formed, and the position of each color frame is detected by the optical sensor 56 described above.

For example, as shown in FIG. 8(a), when four pulses are obtained by the optical sensor 56, it is detected that the color is "yellow", and the take-up reel 18 is stopped by the detection signal. , the color frame is cued. In this embodiment, the optical sensor 56 outputs three pulses when the color of the color frame is "cyan".
Two pulses are output for "magenta" and one pulse is output for "black".

Further, the pinch roller 20 and the guide roller 22 are separated from the platen roller 11 due to the displacement of the cam plate 60.

In FIG. 8, the platen roller 11 is rotated clockwise again.
rhsJ), the clamp mechanism 39 is at the reference position (
The platen roller 11 is located at 906 (FG375 pulse) from the reference position.
It is located at Therefore, when the platen roller 11 is rotated 90° clockwise, the clutch lever 46 and the clutch ring 41 are coupled, and the clamp mechanism 39 that clamps the printing paper 25 then rotates together with the platen roller 511.

Here, as shown in FIG. 13, when the reference pulse iI is output, the platen roller 11 stops.

However, since the platen roller 11 goes too far beyond the reference position, the platen row 511 is rotated counterclockwise (rhsJ in FIG. 8). Then, after obtaining the output of the reference pulse 12 in the opposite direction, the platen motor is stopped after counting 5 times.

■ Print mode Next, as shown in FIG. 14, the holder 13 of the thermal head 12 rotates clockwise, and the heating element 12a of the thermal head 12 is wound around the platen roller 11 via the ink film 15. Press M25 for printing (Fig. 8 (
(see l). Note that the ink film 15 is connected to the guide ball 17.
It is pressed by the heating element 12a and the roller 13a between a and 17b, and comes into contact with the printing paper 25 without loosening.

Also, the lever 21 rotates counterclockwise and the pinch roller 2
0 presses the printing paper 25 on the platen roller 11.

The printer is now ready to print.

Here, by rotating the platen roller 11 clockwise, a reference pulse i3 (shown in FIG. 8) is immediately output, and a predetermined number of consecutive pulses is output using this reference pulse i3 as the starting point for printing. Printing is executed.

Along with the rotation of the platen roller 11, the take-up reel 18
rotates clockwise to wind up the ink film 15 ((b) in FIG. 8). Further, a printing drive signal is supplied to the thermal head 12 along with the rotation of the platen roller 11.

In this embodiment, a line corresponding to 3800 continuous pulses is printed. That is, since 1500 pulses are obtained per revolution of the platen roller 11, printing can be performed for a length of about two and a half revolutions of the platen roller.

In print mode, the guide roller 22 is connected to the platen roller 1.
1, and a pinch roller 20 is in pressure contact with the platen roller 11. This is the platen roller 11
This is to prevent the printing M25 bulging below from coming into contact with the idle roller 22 and hinder paper feeding during printing, and to enable printing on the printing paper 25 that is longer than the outer circumference of the platen roller 11. be.

As shown in FIG. 15, when printing is started by the rotation of the platen roller 11, the three clamp mechanisms
The platen 0 remains clamped until the roller 51a of the release member 51 rotates the clutch lever 44 in the release direction.
- Rotates together with the roller 11. And ink film 1
5 runs in the direction of the arrow as the printing paper 25 is transferred;
When the ink in the ink film 15 passes through the heating element 12a of the thermal head 12, it is heated, melted, and transferred onto the printing paper 25.

As shown in FIG. 16, from the start of printing, the platen roller 11
When the clutch lever rotates approximately 180 degrees, the clutch lever 4
4 is disengaged from the clutch machine m41', and the clamp mechanism 39 stops. Thereafter, the printed paper 25 that has passed through the heating element 12a of the thermal head 12 is driven to be pinched between the platen roller 11 and the pinch roller 20, and is transferred below the platen roller 11.

Therefore, even after the leading edge of the printing paper 25 has stopped, the printing paper 25 is transported as the platen row 511 rotates, and printing continues. As shown in FIG. 17, the platen roller 1
When 3800 consecutive pulses are counted from the start of rotation of the thermal head 1, the supply of print drive signals to the thermal head 12 is stopped, printing is completed, and the thermal head 1
The second holder 13 rotates in the counterclockwise cutting direction, and the thermal head 12 is separated from the platen roller 11. At this time, the end portion of the printing paper 25 is held between the platen roller 11 and the pinch roller 20.

As described above, the first print mode is completed, and the second print mode of the next color frame (cyan and magenta) is completed. When executing the third print mode, the platen roller 11 is further rotated in the o'clock 81 direction in the state shown in FIG. As a result, the printing paper 25 remains clamped and returns to the state shown in FIG. 12 before the start of printing. Since the yellow color frame of the ink film 15 is used up due to the above printing, the second color (cyan) color frame is used for the optical sensor 5.
The film is wound up to the position detected at 6, and the second color frame is cued up.

Thereafter, the operations in the print mode (shown in FIGS. 12 to 17) are repeated to execute the second and third print modes. During this time, the leading edge of the printing paper 25 remains clamped by the clamp lever 45 and the holding member 42, and printing is started starting from the reference pulse that is 1!7 by the encoder 38, so after printing yellow, cyan is printed. , magenta, fine color printing is performed without any color shift, as in the case where the printing paper 25 is fixed to the platen 0-11.

In addition, since the printing paper 25 maintains a friction groove against the platen roller 11 due to the pressure contact force of the pinch roller 20 and the pressure contact force of the thermal head 12, it does not slip on the platen roller 11 during printing. Therefore, the clamping force of the clamp lever 45 that clamps the printing paper 25 does not need to correspond to the force that tries to shift the printing paper 25, and the clamping force of the clamp mechanism 39 is sufficient to move the printing paper 25 to the printing start position. Light force is fine.

■ Paper discharge mode After printing four colors of ink or printing only black ink as described above, in the state shown in FIG. 17, as shown in FIG. 18, the guide arm 23
Rotate clockwise to bring the guide roller 22 into contact with the platen roller 11.

Therefore, the leading edge of the printing paper 25 is clamped by the clamp machine 139.
While being clamped by the pinch roller 20.
Guide roller 22. and the platen roller 11. Note that the guide roller 22 is replaced by the platen roller 11.
Even if the guide arm 23 rotates clockwise in order to come into pressure contact with the guide arm 23, the clamp rock structure 39 is at an upper position that is 1806 turns from the reference position, so the clamp lever 45 hits the extending portion 23d of the guide arm 23. Do not release the clamp without touching it.

As shown in FIG. 19, when the platen roller 11 rotates in the direction J1 (rhyJ in FIG. 8), the end portion 25a of the printing M25 passes through the pinch roller 20 and then flips to engage the light emitting element 58a and receive light. The element 58b is disconnected by 'a'. As a result, the first paper sensor 58 outputs a detection signal of the end portion 25a of the printing paper 25 (I'k in FIG.
zJ).

At the same time that the detection signal of the first paper sensor 58 is output, the platen roller 11 is rotated in the opposite direction (rhs J in FIG. 8). When the platen roller 11 rotates in the reverse direction in this manner, the end portion 25a of the printing paper 25 reaches the paper discharge path 33 formed between the guide plates 30 and 31, as shown in FIG. Further, when the end portion 25a of the printing paper [25] is transferred to the right in the figure, it is inserted between the paper ejection rollers 34 and 35.

Note that the paper ejection roller 35 is driven clockwise when a signal is output from the first paper sensor 58 (rds J in FIG. 8), and as shown in FIG.
5 is held by rotating paper ejection rollers 34 and 35 and pulled out below the tray 26.

As the printing paper 25 is pulled out by the paper discharge rollers 34 and 35, the printing paper 2 is removed from the platen roller 11.
5 becomes less slack, and eventually the clamp wire groove 39 that clamps the leading end of the printing paper 25 is pulled by the printing paper 25 and rotates counterclockwise. Therefore, clamp lever 4
The bottle 45b of No. 5 comes into contact with the extending portion 23d of the guide arm 23, and the clamp is released.

Further, when the leading edge of the printing paper 25 passes between the light emitting element 59a and the light receiving element 59b constituting the second paper sensor 59, the second paper sensor 59 outputs a detection signal ("
I12'') is detected. After the second paper sensor 59 outputs the signal, the paper ejection roller 35 continues to rotate for, for example, 2.5 seconds, thereby causing the paper ejection roller 25 to perform fpI paper.

Further, from the state shown in FIG. 21, the pinch roller 20° and the guide roller 22 are separated from the platen roller 11, and the platen roller 11 rotates in the opening direction, and after two reference pulses are detected, the continuous pulse count reaches 375 pulses. When the weight is lifted, the weight is returned to the state shown in FIG. 1, and the series of operations is completed.

In addition, 1st. Since the second paper sensors 58 and 59 are respectively provided on the guide arm 23, only when the guide roller 22 is in pressure contact with the platen roller 11, the printing paper 2
The passage of 5 is detected. However, in this embodiment, as described above, when the printing paper 25 is transferred by the pressure of the guide roller 22, the first . Second paper sensor 58.
59 outputs a signal, so there is no problem.

In addition, in the above embodiment, the first paper sensor and the second paper sensor are separately provided to detect paper feeding and paper ejection, but only one sensor can be used for both paper feeding and paper ejection. Paper may also be detected.

Further, in the above embodiment, the holding body 13. A description of the drive source for rotating the guide arm 23, lever 50, etc. is omitted, but each member may be driven by a separate motor or actuator such as a solenoid, or a single actuator may be provided for each member. The individual cams may be driven by a motor shade, and each member may be driven via the cams.

Effects of the Invention As described above, in the thermal transfer printer according to the present invention, the leading edge of the printing paper fed to the platen roller is clamped by the clamp levers located at both ends of the platen roller. There is no need to provide a clamp mechanism, and by reducing the diameter of the platen roller, the pressing force of the thermal head can be reduced, and the burden on the drive source of the platen roller can be reduced. Therefore, the rotational phase of the platen roller can be easily controlled, and the rotation of the platen roller can be controlled more accurately.Moreover, since the clamp lever is located outside the platen roller, the clamping mechanism can be configured simply. In addition, the outer surface of the printing paper is placed on a holding member installed in the longitudinal direction of the platen roller, and the inner surface of the printing paper is clamped by a clamp lever, so that the printing paper does not loosen when clamped. It has the advantage that high-definition image quality printing can be performed without paper misalignment due to the rotation of the platen roller.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an example of a thermal transfer printer according to the present invention, FIG. 2 is a cross-sectional view of one end of the platen roller, and FIGS. 3, 4, and 5. 9 is an exploded perspective view showing essential parts of the present invention, FIG. 6 is a plan view showing the position of the leading edge of the printing paper to be clamped, FIG. 7 is a sectional view showing the clamp being released, and FIG. Figure 8 is a time chart showing the operation of the printer, Figures 9 to 12 are front views to explain the operation in paper feeding mode, and Figure 13 is a time chart showing the operation of the printer.
Figure 7 is a front view for explaining the operation of the print mode, respectively.
18 to 21 are front views for explaining the operation in the good news mode, and FIGS. 22 and 23 are schematic configuration diagrams for explaining the conventional printer. 11...-platen roller, 12... thermal head, 15... ink film, 18... take-up reel,
20...Pinch roller, 22...Guide roller, 2
3.--Guide arm, 25.. Printing paper, 26..
・Tray, 28...Paper feed roller, 29-31...Guide plate, 34.35...Paper discharge roller, 38...
- Encoder, 3... Clamp mechanism, 40... Ring, 41... Clutch ring, 42... Holding member, 44... Clutch lever-145... Clamp lever-151... Release member , 56... optical sensor, 58...
...first paper sensor, 59...second paper sensor. Patent applicant: Japan Victor Co., Ltd., r7-1N Patent attorney: Kaneyuki Matsuura 1.
i,・2), :+1,' Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] In a thermal transfer printer in which an ink film and printing paper are overlapped and wrapped around the outer periphery of a platen roller, a thermal head is brought into contact with the back surface of the ink film, and the ink film and printing paper are transferred and printed as the platen roller rotates. , a support member provided at both ends of the platen roller, and a holding member installed between the support members so as to extend in the longitudinal direction of the platen roller, and on which the leading edge of the fed printing paper is placed. a clamp lever that is supported by the support member and clamps both ends of the printing paper placed on the holding member; and a clamp release that separates the clamp lever from the holding member in paper feed mode and paper discharge mode. A thermal transfer printer characterized by comprising: