JPH0550726A - Ink sheet feed device - Google Patents

Abstract

PURPOSE:To provide an ink sheet feed device having simple constitution such that the braking force due to a brake pad is changed corresponding to a change in the diameter of a roll part on a supply side and the back tension force applied to an ink sheet is always kept constant. CONSTITUTION:A brake pad 17 is brought into contact with a roll shaft 5 around which an ink sheet 1 is wound under pressure and a displacement member 14 displaced so as to follow a change in the winding diameter of a roll part 1A on a supply side is hooked with the leaf spring 16 having the brake pad 17 attached thereto and a change in the elasticity of the leaf spring 16 is utilized to change the braking force due to the brake pad 17 corresponding to the winding diameter of the roll part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink sheet conveying device of a recording device using an ink sheet.

[0002]

2. Description of the Related Art An ink sheet is used in which an ink sheet is supplied from a supply-side roll portion having an ink sheet wound around a roll shaft, and the supplied ink sheet is wound around a winding-side roll portion. Recording devices are known.

In this type of recording apparatus, in order to prevent wrinkles and the like from occurring on the ink sheet, it is necessary to apply a proper amount of tension to the ink sheet so as not to cause slack.

As a technique for giving such a tension (back tension) to an ink sheet, for example, a technique using a tension roller according to Japanese Patent Laid-Open No. 60-155483 and a technique according to Japanese Patent Laid-Open No. 1-141073 are disclosed.
Those using a brake pad have been proposed.

In this type of recording apparatus, for example, when the brake pad brakes the roll shaft of the supply side roll portion, if the braking force by the brake pad is always constant, the diameter of the supply side roll portion (ink sheet When the winding diameter is large, the tension force becomes too small, and conversely,
When the diameter is small, the tension force becomes too large. In either case, since an appropriate tension force is not applied to the ink sheet, slippage may occur between the ink sheet and the recording paper in the printing section, or wrinkles may occur in the ink sheet, resulting in poor image quality. Cause

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to change the braking force of a brake pad according to the change of the diameter of a supply side roll portion so that the back tension force applied to an ink sheet is always constant. It is an object of the present invention to provide an ink sheet transporting device having a simple structure, which is configured to be maintained at

[0007]

In order to achieve the above object, the present invention winds the supplied ink sheet while delivering the ink sheet from a supply-side roll portion in which the ink sheet is wound around a roll shaft. In a recording device using an ink sheet, which is wound around the side roll portion, with the supply of the ink sheet, a displacement member that is displaced in accordance with the size of the diameter of the supply side roll portion gradually decreasing,
A brake pad that abuts the roll shaft, and the brake pad is attached, and the displacement member is engaged,
This displacement member is urged in the displacement direction of the displacement member, and the elastic force gradually weakens as the displacement amount of the displacement member increases, so that the braking force of the roll shaft by the brake pad is gradually increased. The present invention proposes an ink sheet conveying device which is provided with a leaf spring for reducing the back tension force applied to the ink sheet so that the back tension force is always constant.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, an ink sheet 1 and a recording paper (image receiving paper) 2 are superposed on each other and a thermal head 3 is provided.
The platen 4 and the platen 4 are passed through a pinching part (printing part). The ink sheet 1 is wound around a roll shaft 5, and the ink sheet 1 is delivered from the wound supply side roll portion 1A. In the printing section, the ink on the ink sheet 1 is transferred to the thermal head 3
It is melted or sublimated by the heat of and transferred onto the recording paper 2.

On the other hand, the winding side of the ink sheet is constructed as follows.

A take-up roller 8 is connected to the ink sheet take-up motor 6 via a slip clutch (torque limiter) 7. A tension roller 9 is pressed against the roller 8 so as to sandwich the ink sheet 1. On the other hand, the take-up roll portion 1B is attached to the free end of the arm rod 12 whose base end is pivotally supported by the shaft 11, and the outer peripheral surface of the take-up roll portion 1B is tensioned by the force of the torsion coil spring 13. It is pressed against 9.

When the ink sheet take-up motor 6 rotates, the take-up roller 8 rotates via the slip clutch 7. With this rotation, the ink sheet 1 is sent in the direction of arrow a, and at this time, the tension roller 9 turns around,
Further, the rotation driving force of the tension roller 9 causes the winding-side roll portion 1B to rotate in the arrow direction. In this way
The ink sheet provided from the supply-side roll unit 1A is wound around the winding-side roll unit 1B.

When the motor 6 rotates, the take-up roller 8 rotates at a part of the slip clutch 7 while causing "slip", and at the rotation speed (linear speed) of the roller 8,
The ink sheet 1 is transported in the direction of arrow a. That is, the transfer speed of the ink sheet 1 is governed by the rotation speed of the take-up roller 8.

An arm-shaped displacement member 14 having a base end portion pivotally supported by a shaft 13 is provided below the supply side roll portion 1A, and a roller 15 is rotatably mounted on the free end portion. There is. On the left side of the displacing member 14, a leaf spring 16 is provided, which has a base end portion at the lower end as a fixed end and is curved rightward in the drawing, and a brake pad 17 is fixed to the free end.

A midway portion of the leaf spring 16 is engaged with the tip bending portion 14b of the branch rod portion 14a which is erected at the midway portion of the displacement member 14. That is, the bent portion 14b is hooked in the middle of the leaf spring 16.

Due to the elastic force of the leaf spring 16, the displacing member 14 is given the habit of rotating in the counterclockwise direction around the shaft 13, and the roller 15 is urged by the elastic force of the leaf spring 16 to cause the supply side roll portion. It is in pressure contact with the outer peripheral surface of 1A. This elastic action is such that the ink sheet 1 of the supply-side roll portion 1A disappears and the roller 15 directly contacts the roll shaft 5.
It's designed to reach you. In this way, the displacement member 14 is biased in the direction in which the roller 15 is directed toward the center of the supply-side roll portion 1A.

On the other hand, the leaf spring 16 presses the brake pad 17 against the roll shaft 5 with a predetermined pressure by this elasticity. The leaf spring 16 has two functions of bringing the brake pad 17 into pressure contact with the roll shaft 5 and the roller 15 into pressure contact with the supply side roll portion 1A.

When the ink sheet 1 is taken up by the take-up roll unit 1B, the supply-side roll unit 1A is rotated in the direction of the arrow. At this time, the brake pad 17 is provided with the supply-side roll unit 1A. Roll shaft 5 that rotates integrally
The braking force is applied to. As a result, a predetermined back tension is applied to the ink sheet 1.

As the ink sheet 1 is supplied, the diameter of the supply-side roll portion 1A gradually decreases. That is, the radius r ₂ of the supply-side roll portion 1A gradually decreases. Although the size of the radius r ₂ changes in this way, the size of the radius r ₁ of the roll shaft 5 does not change and is constant.

As the radius r ₂ gradually decreases,
Since the roller 15 follows the outer peripheral surface of the supply side roll portion 1A, the displacement member 14 is rotated counterclockwise by the elastic action of the leaf spring 16. That is, the displacement member 14 is displaced in the direction in which the roller 15 approaches the axis of the roll shaft 5.

FIG. 2 shows a state in which the ink sheet on the supply side roll portion is about to disappear, and the displacement member 1
4 is in a position to make a maximum turn to the left. Even in such a state, the brake pad 17 is pressed against the roll shaft 5 by the elastic force of the leaf spring 16.

In the initial state in which the supply of the ink sheet 1 is started, the supply side roll portion 1A has the maximum diameter as shown in FIG. 1. At this time, the bent portion 14b of the displacement member 14 is a plate. The spring 16 is forcibly pulled to the right and is greatly bent. At this time, the pressing force of the brake pad 17 against the roll shaft 5 is maximum, and the braking force by the brake pad is maximum.

On the other hand, when the winding diameter of the supply side roll portion 1A becomes smaller, the bent portion 14b escapes to the left, so that the elastic force of the leaf spring 16 engaging with this bent portion is weakened, and the brake is applied. The braking force by the pad 17 is reduced. As shown in FIG. 2, the braking force is the smallest when the supply-side roll portion is about to run out of ink sheets.

As described above, as the displacement amount of the displacement member 14 increases, the elastic force of the leaf spring 16 gradually weakens, and the braking force by the brake pad 17 gradually decreases. As a result, the magnitude of the back tension force at the time of transferring the ink sheet is always maintained constant regardless of the winding diameter of the supply-side roll portion 1A. That is, when the tension force applied to the ink sheet 1 is P as shown in FIG. 1 in the initial state in which the supply of the ink sheet 1 is started and the braking force by the brake pad 17 at this time is F, the tension force P is , P = (F × r ₁ ) / r ₂ . Further, as shown in FIG. 2, when the diameter of the supply side roll portion 1A becomes small, its diameter is r ₂ ′, the tension force of the ink sheet at this time is P ′, and the braking force by the brake pad 17 is F ′. Then, the tension force P ′ is P ′ =
(F ′ × r ₁ ) / r ₂ ′, and to set P = P ′, r
₂ '<because it is r _2, F'<F Tosureba well, according to the illustrated apparatus, it is possible to satisfy such requirements with certainty.

In this embodiment, since the roller 15 that rotates with the rotation of the supply-side roll portion 1A is used as the member that comes into contact with the supply-side roll portion 1A, the ink sheet transfer load is not increased. Also, the ink sheet is not damaged.

As described above, the leaf spring 16 has two functions of bringing the roller 15 into pressure contact with the supply side roll portion 1A and the brake pad 17 into pressure contact with the roll shaft 5. It helps to further simplify the composition of the seed. On the other hand, the displacement member 14 has a leaf spring 1
If a configuration is adopted in which a "spring" different from 6 is used to provide the turning habit, the number of parts increases, this type of configuration becomes complicated, and the device cost easily rises. In this example, such a "spring" is completely unnecessary.

[0026]

According to the present invention, the back tension force can always be maintained at a constant magnitude even if the winding diameter of the supply-side roll portion changes, so that the ink sheet is wrinkled or the ink sheet is wrinkled. It is possible to obtain a stable and high-quality recorded image without slipping between the recording paper and the recording paper. Further, such a function can be achieved with an extremely simple structure, which greatly contributes to the reduction of the device cost.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an ink sheet conveying device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a back tension applying mechanism portion of the ink sheet conveying device according to the embodiment of the present invention.

[Explanation of symbols]

 1 Ink Sheet 1A Supply Side Roll Section 1B Winding Side Roll Section 5 Roll Axis 14 Displacement Member 16 Leaf Spring 17 Brake Pad

Claims (1)

[Claims] 1. An ink sheet is used, wherein an ink sheet is supplied from a supply-side roll portion having an ink sheet wound around a roll shaft, and the supplied ink sheet is wound around a winding-side roll portion. In the recording device,
With the supply of the ink sheet, a displacement member that is displaced in accordance with the size of the diameter of the supply-side roll portion gradually decreasing, a brake pad that contacts the roll shaft, and the brake pad is attached, Engaging the displacement member, urging the displacement member in the displacement direction of the displacement member,
Moreover, as the displacement amount of the displacement member increases,
An ink sheet that is provided with a leaf spring for gradually reducing the braking force of the roll shaft by the brake pad due to the elastic force gradually weakening so that the back tension force applied to the ink sheet is always constant. Transport device.