JPS62103171A - Thermal transfer printer - Google Patents

Abstract

PURPOSE:To enable a transfer recording material and a transfer sheet to be stably released from each other, by applying a substantially constant tension to the transfer sheet and releasing the transfer sheet from the transfer recording material by utilizing the relationship between a releasing force for the sheet and a releasing angle. CONSTITUTION:In a transfer sheet supplying device 6, a braking torque at a friction clutch part 14-a is constant, so that a tension applied to a transfer sheet 8 is constant. On the other hand, in a transfer sheet taking-up device 10, a take-up torque is applied while permitting a friction clutch 14-a to slip relative to a retainer 13, whereby the tension on the sheet is made constant. The transfer sheet 8 is taken up to the thermal head side of a plane in which the sheet 8 is fed past the thermal head 9, whereby the angle between a transfer recording material 2 and the transfer sheet 8 can be made to be large, and the force for releasing the material 2 and the sheet 8 from each other can be reduced. Accordingly, even when the tension on the transfer sheet 8 is decreased as the outside diameter of a transfer sheet roll 22 is increased, stable releasing can be performed.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a transfer sheet feeding/winding device for a thermal transfer printer, and is particularly suitable for applying a constant tension to the transfer sheet and downsizing the printer. The present invention relates to a transfer sheet supply/winding device.

[Background of the invention]

As described in Japanese Patent Application Laid-Open No. 59-190869, the conventional apparatus has a structure in which a friction clutch is used to apply torque to a roll of a transfer sheet, thereby applying a constant tension to the transfer sheet. However, as the transfer sheet is consumed, the outer diameter of the roll on the supply side becomes smaller, and the tension of the transfer sheet increases in inverse proportion to the outer diameter of the roll. Moreover, no consideration was given to the fact that on the winding side of the transfer sheet, the outer diameter of the roll becomes larger and the tension of the transfer sheet becomes smaller.

[Purpose of the invention]

An object of the present invention is to provide a thermal transfer printer that can apply tension to the transfer sheet with little fluctuation even if the outer diameter of the roll changes as the transfer sheet is consumed, and that can stably stab the transfer sheet and the transferred object. Our goal is to provide the following.

[Summary of the invention]

A feature of the present invention is that in a thermal transfer printer, even if the outside diameter of the roll changes due to consumption of the transfer sheet on the transfer sheet supply side and the tension of the transfer sheet changes, the change in the outside diameter of the transfer sheet roll will prevent the transfer from occurring. At the tension loss section of the sheet,
Offsets changes in tension.

It is possible to apply a constant tension with little fluctuation to the transfer sheet. In addition, on the winding side, by utilizing the relationship between the peeling force and peeling angle between the transferred material and the transfer sheet, the transferred material and the transfer sheet can be reliably peeled off even if the outer diameter of the transfer sheet roll changes. It is in.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 to 7. FIG. 1 shows the main body of the thermal transfer printer device, including a platen 1 for feeding the transferred object 2 in the sub-scanning direction, an auxiliary roller 7, a transfer sheet supply device 6 for supplying the transfer sheet 8, and a transfer sheet after transfer. A transfer sheet winding device 10 that winds up the transfer sheet 8, a thermal head 9 that applies heat to the transfer sheet 8 and transfers the transfer material 23 onto the transfer target 2, a control device 5 that controls the operation of these devices, and a power source for these devices. It consists of a power supply device 4 that supplies power, a case 19 that houses these, and the like. To transfer onto the transfer target 2, the platen 1 is raised. Alternatively, the transfer sheet 8 is pulled out from the transfer sheet supply device 6 by lowering the thermal head 9, passes between the platen 1 and the thermal head 9, and is wound around the core 20 of the transfer sheet winding device 10. Next, the thermal head 9 or platen 1 is returned to its original state. Next, platen 1 is connected to a platen drive device (not shown).
By rotating the transfer sheet 8 and synchronizing with this and winding up the transfer sheet 8 by the transfer sheet winding device 10, the transferred object 2 is passed between the platen 1 and the auxiliary roller 7, and via the platen 1 and the transfer sheet 8 to the thermal head 9. The preparation for transfer is completed. These operations are performed according to commands from the control device 5. For transfer to the transfer object 2, the control device 5 decomposes a transfer command from a host computer or the like (not shown) into the main scanning direction and the sub-scanning direction, sends data in the main scanning direction to the thermal head 9, and transfers the data to the thermal head 9. When power is supplied from the power supply 4 to a heating element (not shown) of the thermal head 9 in the area to be transferred based on data, the heating element generates heat and the transfer material 23 of the transfer sheet 8 that is in contact therewith melts. Alternatively, it is sublimated and transferred to the transfer target 2. Next, the platen is rotated by the platen driving device and the transferred object 2 is sent in the sub-scanning direction. At the same time, the transfer sheet 8 is also transferred to the transfer sheet winding device 1.
o to send in the sub-scanning direction. The data to be transferred is also sent from the control device 5 to the thermal head 9.
The transfer material 23 is transferred onto the object 2 by receiving electric power from the power supply device 4 to the heating element. By repeating these series of operations, characters, figures, etc. can be transferred onto the transfer object 2 using the transfer material 23 of the transfer sheet 8. When the transfer is completed, the transferred object 2 is discharged from the printer.

When supplying or winding up the transfer sheet 8,
If proper tension is not applied to the transfer sheet 8, the transfer sheet 8 will sag and wrinkle, resulting in poor transfer, poor winding, or entanglement with other constituent members, resulting in the transfer sheet 8 being cut.

In order to prevent these accidents, in the transfer sheet supply bag @6, the core 20 on which the transfer sheet 8 is wound is held by the holder 13 and the shaft 16 that receives it, and the holder 13 and the winding The rotation stopper 21 is constructed so that the cores 20 rotate in synchronization, and the friction member 14 is pressed against the holder 13 by compressing and attaching the elastic body 15, thereby constructing the friction clutch 14-a. When the transfer sheet 8 is wound up by the transfer sheet winding device 10, the slack of the transfer sheet 8 is first absorbed, tension is gradually generated in the transfer sheet 8, and this tension causes the transfer sheet roll 229 to roll up the core 20. Torque that attempts to rotate the holder 13 is generated through the holder 13. When this torque becomes larger than the control torque by the friction clutch 14-a, the holder 139 winding core 20. The transfer sheet roll 22 starts rotating, and the transfer sheet roll 2
A transfer sheet 8 is fed from 2. Furthermore, transfer sheet 8
When the transfer sheet 8 is wound up, the braking torque of the friction clutch portion 14-a is constant, so the tension applied to the transfer sheet 8 is constant.

On the other hand, in the transfer sheet winding device 10, the friction member 14 is made rotatable by the holder 13 with respect to the transfer sheet supply device 6, and is constituted by a drive section 25. The operation is performed by the drive unit 2 at a speed faster than the winding speed of the transfer sheet 8.
The transfer sheet 8 is wound onto the transfer sheet roll 22 on the winding core 20 by rotating the friction member 14 at step 5 and applying winding torque while slipping against the holder 13 using the friction clutch 14-a. . At this time, the friction clutch 14
Since the torque transmitted from -a to the holder 13 is constant,
The tension of the film on the take-up side remains constant.However, as the transfer sheet 8 is consumed by repeating transfer to the transfer object 2, the transfer sheet supply device 6 uses the transfer sheet roll 22.
The outer diameter of Therefore, the tension of the transfer sheet 8 is
It increases in inverse proportion to the outer diameter of the transfer sheet roll 22.

To explain this, the outer radius of the transfer sheet roll 22 is R1, the tension of the transfer sheet is T, the force generated by the elastic body 15 to push the friction member 14 and the holder 13 is P, and the friction clutch 14 is
-a and the rotation center of the holder 13 is γ, and the friction coefficient at the friction clutch 14-a is μ, then the torque Qz generated in the holder 13 due to the tension of the transfer sheet 8 is Q, =
= T
×γ, and since these are balanced, TXR=μ
×P×γ, and the tension T is T=μxpxγ/R. Here, since the friction coefficient μ, the pushing force P of the elastic body 13, and the distance γ between the rotation center of the friction clutch 14-a and the holder 13 are constant and do not change, the tension T of the transfer sheet 8 is It is inversely proportional to the diameter R. Therefore, the tension of the transfer sheet on the ribbon supply device 6 side changes by the ratio of the maximum diameter to the minimum diameter of the transfer sheet roll 22, and immediately after the transfer sheet roll 22 is replaced, the outer diameter of the transfer sheet roll 22 is large. Since the tension of the transfer sheet 8 is small, minute wrinkles caused by thermal contraction and thermal expansion of the transfer sheet 8 due to heat generated by the heating element of the thermal head 9 cannot be absorbed, resulting in a reduction in transfer quality. Conversely, when the transfer sheet 8 is consumed and the outer diameter of the transfer sheet roll 22 becomes smaller, the transfer sheet 8
The tension increases, making it impossible to wind up the transfer sheet 8, resulting in transfer omission. In severe cases, the transfer sheet 8 may be cut.

On the other hand, on the transfer sheet winding device 10 side as well, for the reasons stated above, the tension applied to the transfer sheet 8 on the winding side fluctuates depending on the change in the outer diameter of the transfer sheet roll 22, and the tension applied to the transfer sheet 8 on the winding side varies. When the tension applied to the transfer sheet roll 22 becomes small, the transfer sheet roll 22 cannot be wound up. Also, thermal head 9
As a result, the transfer material 23 transferred to the transferred object 2 cannot be peeled off from the base material 24, and the transfer sheet 8 and the transferred object 2' are brought toward the auxiliary roller 7 side, resulting in a jam. There was a drawback.

The present invention has been made in view of the above-mentioned drawbacks, and the following will be described below.
This embodiment will be explained with reference to FIGS. 4 to 7. Transfer sheet supply device6. In both the transfer sheet winding device 10, the winding direction of the transfer sheet 8 is such that the transfer material 23 is on the winding core 2o side, the base material 24 is wound on the outside of the transfer sheet roll 22, and the transfer sheet 8 is wound around the outer diameter of the transfer sheet roll 22. The supply/take-up side of the thermal head 9 is disposed closer to the thermal head 9 than the transfer sheet 8 passing surface of the thermal head 9.

With the configuration described above, the transfer sheet 8 passing over the thermal head 9 is supplied to the heating element of the thermal head 9 through a stable path while sliding on the contact portion 26 of the thermal head 9. , auxiliary roller 7
Accidents such as entanglement with the platen 1 can be prevented. Furthermore, a transfer sheet supply device 6. The transfer sheet winding device 10 includes:
Just before and after the thermal head, and at platen 1. Since it can be placed below the auxiliary roller 7, the thermal transfer printer can be made smaller.

In addition, in the transfer sheet supply device 6, since the transfer material 23 of the transfer sheet 8 is wound around the core 20 side, the transfer sheet 8 has a large outer diameter of the transfer sheet roll 22 at the contact portion 26 of the thermal head 9. In this case, the contact portion 26 of the transfer sheet 8
The wrapping angle θl is larger than the wrapping angle 02 when the outer diameter of the transfer sheet roll 22 is small. The tension between the contact portion 26 of the thermal head 9 and the transfer sheet 8 on the heating element side of the thermal head 9 is set to T1. Contact part 26 of thermal head 9
The tension of the transfer sheet 8 between the transfer sheet roll 22 and the transfer sheet roll 22 is T2
, the wrapping angle of the transfer sheet 8 at the contact portion 26 of the thermal head 9 is θ, and the contact portion 26
and the friction coefficient of the transfer sheet 8 is μ, then the transfer sheet 8
There is a relationship between Tt=TzX8μ'' between the tensions Tl and T2.
Considering the case where the tension changes by half from to R', the tension on the transfer sheet 8 when the radius is R is T2, and the tension on the transfer sheet 8 when the radius is R' is Tz', then 2' = 2 x T.
2, and Tz will change twice.

However, when T1 is the radius R, the wrapping angle θ2 = 82 degrees, when the radius is R', the wrapping angle θ1 = 60 degrees, and the friction coefficient μ between the contact portion 26 and the transfer sheet 8 is 0.4. The tension T1 of the transfer sheet 8 when the radius is R' is as follows, and the tension Tz' of the transfer sheet 8 when the radius is R' is as follows.The ratio of TL and T1' is approximately 1.7 times T.
The change in z is smaller than twice. Conversely, when the base material 24 of the transfer sheet 8 is wound around the core 20 and the transfer sheet 8 is supplied, the variation in T1 becomes larger than twice the variation in T2,
Change will be encouraged. Therefore, by winding the transfer material sheet 8 with the transfer material 23 facing the winding core 20 and supplying the transfer sheet 8 to the heating element part of the thermal head 9 while sliding it on the contact part 26 of the thermal head 9. This makes it possible to reduce fluctuations in the applied tension on the transfer sheet 8, and prevent accidents such as wrinkles, poor transfer, and cutting of the transfer sheet 8.

On the other hand, in the transfer sheet winding device 10, a transfer material 2 is heated and transferred onto an object 2 by a heating element of a thermal head.
3 from the base material 24 of the transfer sheet 8, and the transfer sheet 8 must be tightly wound around the winding core 20 while preventing wrinkles. In order to prevent accidents such as cutting of 8, it cannot be made too large. Therefore, when we focus on the force required to peel off the transfer sheet 8 and the transferred object 2, we find that as the angle between the transferred object 2 and the transfer sheet 8 increases, the force required to peel off becomes smaller. . For this reason.

By winding up the transfer sheet 8 toward the thermal head 9 side from the transfer sheet 8 passing surface of the thermal head 9, the angle between the transferred object 2 and the transfer sheet 8 can be made large, and the transfer object 2 and the transfer The peeling force of the sheet 8 can be reduced. When the angle between the transferred object 2 and the transfer sheet is 30 degrees.

A peeling force of 250 g is required, but if the angle is set at 60 degrees, the peeling force can be reduced to 70 g. In addition, by winding the transfer sheet 8 in the direction in which the transfer material 23 side is wound around the core 20 side, as the transfer sheet 8 is consumed, the outer diameter of the transfer sheet roll 22 increases, and the transfer sheet 8 is Even if the applied tension is reduced, the angle formed between the transferred object 2 and the transfer sheet 8 becomes larger, so the peeling force between the transferred object 2 and the transfer sheet 8 becomes smaller, so that stable pricking can be performed. By the way, when the outer diameter of the transfer sheet roll 22 changes three times, when the transfer sheet roll 22 is small, the tension of the transfer sheet 8 is 300 g, and at this time, the angle between the transferred object 2 and the transfer sheet 8 is 0. is 60 degrees, and when the outer diameter of the transfer sheet roll 22 is tripled, the angle θ3 between the transferred object 2 and the transfer sheet 8 is 90 degrees. When the outer diameter of the transfer sheet roll 22 is small, When the tension of the transfer sheet is 300 g, the force required for peeling off is 75 g, and it is possible to stab the transfer sheet. Furthermore, when the outer diameter of the transfer sheet roll 22 is tripled, the tension of the transfer sheet 8 is 100.
g, and the necessary peeling force at this time is 25 g. - Contrary to the old invention, the base material 24 of the transfer sheet 8
is wound around the core 20 side, the transfer sheet roll 2
When the outer diameter of the transfer sheet 8 is small, the tension of the transfer sheet 8 is 300
g, and the force required for peeling off is 75 g. However, if the outer diameter of the transfer sheet roll 22 becomes three times as large, and the angle between the transferred object 2 and the transfer sheet 8 becomes 30 degrees. Then, the force required to peel off the transferred object 2 and the transfer sheet 8 is 250 g.

However, at this time, the tension applied to the transfer sheet 8 is 1
Since there is not 00gL, the transfer sheet 8 cannot be peeled off from the object 2 to be transferred. For these reasons, transfer sheet winding device @1
0, the transfer sheet 8 is wound up toward the thermal head 9 side from the transfer sheet 8 passing surface on the thermal head 9, and the transfer material 23 of the transfer sheet 8 is wound up toward the winding core 20 side. The transfer sheet 8 can be peeled off stably, and accidents such as jamming of the transfer sheet 8 and cutting of the transfer sheet 8 can be prevented.

〔Effect of the invention〕

According to the present invention, it is possible to apply tension with small fluctuations to the transfer sheet, and also to stably stick the transfer sheet to the transferred object, resulting in a thermal transfer printer that is small, lightweight, and has stable quality. There is.

[Brief explanation of drawings]

FIG. 1 is a side view showing the principle of a thermal transfer printer, FIG. 2 is a front view of a transfer sheet supply device, and FIG. 3 is a front view of a transfer sheet winding device. Figure 4. FIG. 5 is a side view showing an embodiment of the present invention, and FIG. 6 is a side view showing an embodiment of the present invention.
6 is an enlarged view of the thermal head section of FIG. 5. FIG. FIG. 7 is a diagram showing the peeling force between the transfer sheet and the transferred object. DESCRIPTION OF SYMBOLS 1... Platen, 2... Transfer target, 4... Power supply device, 5... Control device, 6... Transfer sheet supply device,
7... Auxiliary roller, 8... Transfer sheet, 9... Thermal head, 10... Transfer sheet winding device, 13.
...Holder, 14...Friction member, 14-a...Friction clutch, 15...Elastic body, 16...Shaft, 19...
・Case, 20... Winding core, 21... Rotation stopper, 2
2... Transfer sheet roll, 23... Transfer material, 24...
...Base material, 25...Drive unit, 26 Light 4 drawing S day II 2

Claims (1)

[Claims] 1. In a thermal transfer printer equipped with a transfer sheet supply and winding device that winds the transfer sheet into a roll around a core and applies tension to the transfer sheet using a friction clutch or brake for supplying and winding the transfer sheet, On both the supply and take-up sides, the transfer sheet is wound in such a way that the base material of the transfer sheet is on the outside, and the transfer sheet supply and take-up part on the outer diameter of the transfer sheet roll is positioned closer to the transfer sheet passing surface of the thermal head. , a thermal transfer printer characterized by being placed on the thermal head side.