JP2527048B2 - Thermal transfer recorder - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer recording apparatus, and more specifically, to a pressure contact releasing means via a pinch roller lever for rotatably supporting front and rear pinch rollers. In the first embodiment, the pressure contact releasing means for one pinch roller is constituted by a rotating cam provided so as to slide on one pinch roller lever, and the pressure contact releasing means for the other pinch roller is The protrusion provided on the one pinch roller lever causes the other pinch roller lever to swing directly.

In a second embodiment, a pinch roller open lever is interposed between the two pinch roller levers, and the other pinch roller lever swings corresponding to the swing of one pinch roller lever is operated by one pinch roller. The present invention relates to a thermal transfer recording apparatus that can be selectively operated by a connection point switching mechanism that brings the same state or a different state.

[Prior Art] In FIG. 5A, the platen 3 is belt-driven by the motor 26 shown in FIG. 5B.

Further, the feed rollers 18 and 16 and the cam 9 are driven by a belt different from the belt when the platen 3 is driven. The rear pinch roller 4 and the front pinch roller 5 are
Each of the front and rear pinch roller levers 7 and 6 is supported, and tension springs 11 acting between the front and rear pinch roller levers are constantly pressed against the outer peripheries of both sides of the platen 3 so as to follow the rotation of the platen 3. The discharge roller 20 is driven by being gear-connected to the feed roller 16.

The pinch roller 17 is pressed against the feed roller 16 by a spring (not shown) and is driven by the rotation of the feed roller 16.

The discharge pinch roller 21 has the same structure as the discharge roller 20.
It is designed to follow the rotation of.

Rear pinch roller lever 6, front pinch roller lever 7,
The cams 9 and 9 are arranged outside the frames on both sides, and the rear pinch roller 4 is attached to the frames on both sides by a bearing 16 ″ common to the feed roller 16 and the rear pinch roller lever 6.

The cams 9 are fixed on both sides of a shaft 9'passed by bearings mounted on the frames on both sides, and the front pinch roller lever 7 can swing about a stud 23 serving as a connecting shaft mounted on the frames on both sides as a fulcrum. The rear pinch roller lever 6 is also supported by the bearing 16 ″ of the feed roller 16 and the shaft 16 ′.
Is oscillated around.

Further, electromagnetic clutches 24 and 25 shown in FIG. 4B are attached to the shaft ends of the feed roller 18 and the cam 9, respectively.
The feed roller 18 is driven only when the electromagnetic clutch 24 and the cam 9 are driven, and the limit switch 8 is turned on / off depending on the lift amount of the cam when the cam 9 rotates.

In the above conventional apparatus, the rear pinch roller 4 and the front pinch roller 5 are connected to the platen 3 before starting printing (including when the power switch is turned off) and after finishing printing, as shown in FIGS. 5A and 5B.
On the other hand, the pressure is still applied by the spring 11.

The cam 9 causes the rear pinch roller lever 6 to swing counterclockwise when viewed from the direction shown in FIG.
The operation of separating the platen 3 from the platen 3 is performed for a preset time after the print start command is issued. This is to remove the slack of the paper between the front pinch roller 5 and the rear pinch roller 4. is there.

[Problems to be Solved by the Invention] In the above conventional apparatus, before printing is started (power switch is turned off).
(Including time) and after printing, the rear pinch roller 4 and the front pinch roller 5 are kept in pressure contact with the platen 3 by the spring 11, so if left in this state for a long time,
The part where the rear pinch roller 4 and the front pinch roller 5 of the platen 3 are in contact with each other is dented, and when the dented part of the platen 3 comes to the heating element part of the thermal head 1 in the next printing process, it is normal. It was not transferred, and was a cause of color shading and color unevenness.

[Means for Solving the Problems] In order to solve such a problem, the present invention sets the rear pinch roller 4 and the front pinch roller 5 to the platen 3 before the start of printing (including when the power switch is OFF) and after the end of printing.
It was developed for the purpose of eliminating color misregistration and color unevenness caused by the platen dents even when printing is started after leaving it for a long time.

In order to separate the front and rear pinch rollers from the platen, the following two means were adopted.

1) A protrusion is provided on the rear pinch roller lever, a protrusion engageable with the protrusion is provided at a position facing the protrusion of the front pinch roller lever, and when the rear pinch roller lever swings by rotation of a cam. , The front pinch roller lever also swings in opposite directions, and both pinch rollers are separated from the platen to prevent the platen from being dented due to pressure contact for a long time.

2) In the above 1), the swing of the rear pinch roller lever is directly transmitted to the front pinch roller lever so as to swing in opposite directions so that both pinch rollers are separated from the platen or pressed against the platen. Instead of the above, a pinch roller lever open mechanism is added as an intermediate transmission mechanism that is interposed between the rear pinch roller lever and the front pinch roller lever to transmit the swing of the rear pinch roller lever to the front pinch roller lever.

This pinch roller lever opening mechanism is a first common shaft which is connected by a pin as a common shaft and swings with respect to each other.
And a second pair of pinch roller open levers (hereinafter abbreviated as "open levers"), and an L-shaped groove formed at one end of the first open lever in the longitudinal direction, the second open lever is almost A stud provided in the intermediate portion is engaged and slidable in the L-shaped groove so that the connecting position of the first and second open levers can be changed.

One end apart from the common shaft is coupled to a stem of a driving body such as an electromagnetic solenoid, and the other end is coupled to an end of the front pinch roller lever opposite to the pinch roller mounting end, By swinging the open lever, the front pinch roller lever is swung to bring it into or out of contact with the platen.

[Operation] 1) In the first means, when the rear pinch roller lever is swung by the cam, the front pinch roller lever is swung in the opposite direction to the rear pinch roller lever, and the rear and front pinch rollers are moved to the platen. At the same time, they are pressed together or separated.

2) In the second means, the swing of the rear pinch roller lever by the cam is first transmitted to the first open lever, and further connected by the stud engaged with the L-shaped groove of the first open lever. Swing the second open lever. The second open lever and the front pinch roller lever are relatively oscillatable at one end portion in the longitudinal direction about a common connecting pin as an axis, and the front pinch roller lever is oscillated by the second open lever. The roller lever is swung, and the front pinch roller is pressed against or released from the platen.

Therefore, the front pinch roller lever directly reacts to the swing of the rear pinch roller lever at a certain connecting position,
In another connecting position, the swing of the rear pinch roller lever is not transmitted to the front pinch roller lever.

When a driving body such as an electromagnetic solenoid is turned on, its stem is pulled inside the solenoid against the tension of the spring, and the second
The open lever of oscillates about the connection point with the front pinch roller lever as an axis.

By this swinging, the stud of the second open lever engaged with the L-shaped groove of the first open lever slides in the L-shaped groove, so that the stud of the second open lever with respect to the first open lever is slid. The connecting position is changed so that the swing of the front pinch roller lever can be operated independently of the rear pinch roller lever.

As a result, only the rear pinch roller can be separated from the platen, or both pinch rollers can be pressed against the platen or separated from the platen.

The operation process of the present device will be described with reference to the table showing the operation sequence in FIG. 4, mainly based on the relative positions of the L-shaped groove of the first open lever and the stud of the second open lever.

First, turn on the power switch (sequence 1) and rotate the cam 9 counterclockwise as seen in FIG. 2A.
Turns off and stops (sequence 2).

During this time, the rear pinch roller lever rotates to the right, both the front and rear pinch rollers are pressed against the platen, and the relative positions of the L-shaped groove and the stud are as shown in FIG. 3A.

Next, when the solenoid 13 is turned on (sequence 3), the relative position is as shown in FIG. 3C. Then, the cam 9 is rotated clockwise to stop the limit switch 8 when it is ON, and then the solenoid 13 is turned OFF (sequence 4).

With this, only the rear pinch roller is detached from the platen, the relative position is as shown in FIG. 3D, and it is taken out from the paper cassette 19, and the printing process is started. Next, rotate the cam 9 counterclockwise to turn off the limit switch 8.
Stop at (order 5).

The rear pinch roller again presses against the platen to slacken the paper, and the printing process starts. During this time, the stud is returned by spring 14 to the position of FIG. 3A. The cam 9 remains stopped and the solenoid 13 remains off, and the printing process proceeds (sequence 6).

When printing is completed, the cam 9 is rotated counterclockwise and stopped by turning on the limit switch (sequence 7).

With this, the front and rear pinch rollers separate from the platen,
The relative position remains the same as in FIG. 3A. Then, turn off the power switch to finish (sequence 8).

The relative position remains the same as in FIG. 3A. When finishing the next printing, turn on the coast switch and repeat from order 1.

[Embodiment] Embodiment 1 FIG. 1 shows a pair of front and rear pinch roller levers 7, which respectively swingably support a front pinch roller 5 and a rear pinch roller 4, only by a pair of pinch roller levers. FIG. 6 is a schematic side view showing an example of the first embodiment of the press-contact releasing mechanism in which 6 is operated by the cam 9 to be swung to be separated from the platen 3.

In the figure, the front pinch roller lever 7 and the rear pinch roller lever 6 support the front and rear pinch rollers 5 and 4, respectively, and are swung around the connecting shaft 23 and the shaft 16 ', and the platen 3 is opposed thereto. Insert from the outer periphery and press-contact.

The rear pinch roller lever 6 and the front pinch roller lever 7 have projections 6'and 7'which are always engaged on their inner surfaces.

Except during the start of printing and the subsequent printing, when the cam 9 is rotated so that the large-diameter portion of the cam 9 engages with the projection 6 ″ on the outer portion of the rear pinch roller lever 6, the front and rear pinch rollers are pressed. The roller levers 7 and 6 resist the pulling force of the spring 11,
The rear pinch roller lever 6 is swung counterclockwise, and the front pinch roller lever 7 is swung clockwise, and is separated from the platen 3.

Example 2 As shown in FIG. 2A, the electromagnetic solenoid 13 and the pinch roller open mechanism 10 are installed outside the frames (not shown) on both sides forming the device, and when the rear pinch roller lever 6 swings, The front pinch roller lever 7 is swung through a pinch roller opening mechanism 10 with which a part of the pinch roller lever 6 is engaged, and this swing causes the rear pinch roller 4 and the front pinch roller 5 to move to the platen. It is designed to break away from 3.

This pinch roller open mechanism 10 includes a first open lever 10 'and a second open lever 10' which is swingably connected to the first open lever 10 '.
The first open lever 10 'is provided with an L-shaped groove 29, and the second open lever 12 is provided with a stud 28 so that the stud 28 is L-shaped. Slidably engaged along the V-shaped groove 29.

When the electromagnetic solenoid 13 is OFF and the stem 13 'is protruding, the L-shaped groove of the first open lever 10' is arranged so as to swing the front pinch roller lever 7 when the rear pinch roller lever 6 swings. 29 horizontal end (left end in the figure)
The stud 28 of the second open lever 12 is located at the position.

Second open lever 12 and first open lever 10 '
Is connected by a pin 12 'so that they can swing together at one end (lower end in the figure) of the second open lever 12,
On the other end (top in the figure) of the open lever 12 is a slot 12 "
Is provided, and the plunger stem 13 ′ of the electromagnetic solenoid 13 is provided.
Slidably engaged with the pin 13 "of.

The spring 14 is the stud of the second open lever 12.
28 is a function of being always brought close to one of the L-shaped grooves 29 of the first open lever 10 'and a function of making the first open lever 10' always swing upward in FIG. 2A. The electromagnetic solenoid 13 is attached so that the electromagnetic solenoid 13 also acts so as to move smoothly.

Operation method Fig. 2A and Fig. 3A show the state after printing is completed. The cam 9 is rotated until the limit switch 8 is turned on (at this time, the electromagnetic solenoid 13 is turned off), and the rear pinch roller is turned on. The lever 6 swings counterclockwise together with the rear pinch roller 4, and this swinging pushes the first open lever 10 ′ of the pinch roller open mechanism 10 clockwise to move the first open lever 10 ′ to the second position as shown in FIG. 2A. 1 open lever 10'L
Since the relative positions of the groove 29 and the stud 28 of the second open lever 12 are as shown in FIGS. 2A and 3A, the front pinch roller lever 7 swings clockwise and the rear pinch roller 4 and the front pinch roller 5 are both separated from the platen 3.

In this case, the elongated hole 12 ″ of the second open lever 12 slides downward with respect to the pin 13 ″ of the stem 13 ′ of the electromagnetic solenoid 13 in the figure, and the movement of the second open lever 12 causes the stem 1 ′ to move.
It is designed not to exert excessive force on 3 '.

Even if the electromagnetic switch is turned off in this state, the rear pinch roller 4 and the front pinch roller 5 are held while being separated from the platen 3.

Next, when given from the print start command, the cam 9 is rotated until the limit switch 8 is turned off, the rear pinch roller lever 6 is rotated clockwise, the front pinch roller lever 7 is rotated counterclockwise, respectively in the opposite directions. The rear pinch roller 4 and the front pinch roller 5 are pressed against the platen 3 together. This is the state of FIGS. 2B and 3B.

In this case, the second open lever 12 is moved upwards in the figure by the first open lever 10 so that the pin 13 ″ is in the slot 1
Located below 2 ″.

Next, when the electromagnetic solenoid 13 is turned on, it will be shown in FIG. 2C and 3C.
As shown, the second open lever 12 swings clockwise and the stud 28 moves to the right end of the L-shaped groove 29.

Next, as shown in FIGS. 2D and 3D, the cam 9 is rotated until the limit switch 8 is turned on.

As a result, the rear pinch roller 4 is disengaged from the platen 3, but the stud 28 does not move due to play due to the gap in the L-shaped groove 29 of the first open lever 10 'in the vertical direction in the figure, so the front pinch roller 5 is Do not detach from the platen.

At the same time, the electromagnetic solenoid 13 is turned off, but the stud 28
Is restrained by the L-shaped groove 29 and kept in its original position,
At the same time, the feed roller 18 is driven to drive the paper cassette 19
When the paper is fed out from the paper, and the leading edge of the paper is detected by an optical sensor (not shown) provided between the feed roller 16 and the platen 3, the drive of the feed roller 18 is stopped and the paper is rotated freely while the paper is discharged from the discharge roller 20 and the discharge guide 22. And send it for a specified length.

Next, the cam 9 is rotated until the limit switch 8 is turned off, the rear pinch roller 4 is brought into pressure contact with the platen 3, and the paper is further conveyed by a predetermined length to transfer the paper between the platen 3 and the front pinch roller 5. Allow the slack to be removed.

By the rotation of the cam 9, the first open lever 10 '
Moves counterclockwise, L-shaped groove 29 and stud 28
The relational position with and is as shown in FIG. 3C, and the stem 13 ′ in the retracted position is moved to the advanced position by the spring 14.

Next, the paper is retracted and stopped, and is advanced again until the end of printing, and the front pinch roller 5 and the pinch roller 4 remain in this state and enter the 2B state.

When printing is completed, the operation as described in the first description is performed so that the state shown in FIG. 2A is obtained.

[Effects of the Invention] As described in detail above, the thermal transfer recording apparatus of the present invention separates the pinch rollers that press the platen from the outer periphery of both sides after the printing is completed or even when the power switch is turned off after the printing is completed. By providing the mechanism for preventing the platen from being deformed, the positioning accuracy of the recording paper is improved, and in the case of the color thermal transfer recording apparatus, the reciprocal positioning accuracy of the recording paper is improved to prevent color misregistration and color misregistration. The effect of eliminating color unevenness is great.

[Brief description of drawings]

FIG. 1 is a schematic side view showing a first embodiment of a thermal transfer recording apparatus of the present invention, FIGS. 2A to 2D are schematic side views showing a second embodiment of the present invention, and FIGS. 3D is an enlarged view showing the positional relationship between the L-shaped groove and the stud in FIGS. 2A to 2D, and FIG. 4 is a list showing the relationship between the operation of the thermal transfer recording apparatus of the present invention and related members. FIG. 5A is a table, FIG. 5A is a schematic side view of a conventional thermal transfer recording apparatus, and FIG. 5B is a drive explanatory diagram of the platen and cam of FIG. 5A. Explanation of symbols 1: Thermal head, 2: Ink sheet, 3: Platen, 4: Rear pinch roller, 5: Front pinch roller, 6: Rear pinch roller lever, 7: Front pinch roller lever, 9: Cam, 10: Pinch Roller open mechanism, 10 ': first open lever, 12: second open lever, 12': pin, 12 ": long hole, 13: solenoid, 13" pin, 23: connecting shaft, 28: stud, 29 : L-shaped groove.

Claims (3)

(57) [Claims] 1. A pair of pinch rollers, a front platen roller and a rear pair pinch roller, which opposes the platen roller and is oscillated from both sides of the outer periphery of the platen roller to come into contact with the platen roller to sandwich a sheet between the platen roller and the sheet. , A cam for giving the swing to the rear pinch roller of the pair of pinch rollers, provided as a pressure contact releasing means provided in the thermal transfer recording apparatus, and one tip end portion to which the rear pinch roller is attached, A rear pinch roller lever provided with three parts, a part externally fitted to the feed roller also serving as a shaft, and the other tip end part contacting the cam, and a part internally fitted to the front pinch roller, A front pinch roller lever having two parts, that is, a part into which another rotary shaft provided at a predetermined position facing the rotary shaft is fitted, and the both pinch roller levers for applying the spring pressure. In the pressure contact releasing means having a tension spring stretched between the pinch roller levers, the rear pinch roller lever is inwardly closer to the front pinch roller than the feed roller also serving as a rotation shaft, in addition to the three parts. In addition to the above-mentioned two parts, the front pinch roller has a protrusion projecting toward the rear pinch lever, and a protrusion that abuts against the protrusion of the rear pinch roller lever. The front and rear pinch roller levers are pivoted in the opposite direction, and the front and rear pinch roller levers are pivoted in the opposite direction. A thermal transfer recording apparatus, characterized in that the subsequent pinch roller is removed from the pressure contact with the platen roller. 2. A thermal transfer recording apparatus comprising: a platen roller; and a pair of pinch rollers, which are opposed to the platen roller and are pressed against each other from both sides of the outer periphery of the platen roller to sandwich a sheet and an ink sheet, and Each of the front and rear pair of pinch rollers is swingably supported at one end, and the front and rear pair of pinch roller levers and the pair of pinch roller levers before and after being pressed against or separated from the platen roller. A pinch roller pressure contact releasing means provided in each of them, a cam for swinging the rear pinch roller lever, an engaging portion provided in a part of the rear pinch roller lever and engaging with the cam, and a front pinch roller. A pressure contact releasing means for the rear pinch roller lever, which includes a portion that engages with the lever, and one end with respect to the front pinch roller lever. A first pinch roller open lever which is swingably connected to each other by the same rotary shaft and has an L-shaped through groove at a position apart from the rotary shaft; and the front pinch roller lever at one end in the longitudinal direction. Studs that are swingably connected to each other and that are provided approximately in the middle in the longitudinal direction are slidably engaged in the L-shaped through groove, and the first pinch roller open lever is A second pinch roller oven lever having a mutually changeable connection position and swingably connected to each other; and a pressure contact releasing means for the front pinch roller lever, and a second pinch roller open lever. On the other hand, there is provided a connection point switching mechanism which is connected at the other end in the longitudinal direction of the rear pinch roller, the connection point switching mechanism changing an engagement position between the stud and the L-shaped through groove. When transmitting the swinging motion of the lever to the front pinch roller lever, the rear pinch roller open lever is interposed between the first and second pair of pinch roller open levers which is interposed between the pair of pinch roller levers. A thermal transfer recording apparatus capable of selectively arranging a front pinch roller at an arbitrary position of pressure contact or separation in correspondence with pressure contact or separation of a roller with respect to a platen roller. 3. The thermal transfer recording apparatus according to claim 2, wherein the connection point switching mechanism is an electromagnetic solenoid connected to the other end of the second pinch roller open lever, and the reciprocating motion of an operating stem of the electromagnetic solenoid. A connecting member such as a stud that is erected on the second pinch roller open lever is L of the first pinch roller open lever.
A thermal transfer recording apparatus, characterized in that a position for engaging in the character-shaped structure is changed, and a connection positional relationship between the first and second pinch roller open levers is changeable.