JPH0229080Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Application of the Invention) The present invention relates to an appropriate feeding device for a strip-like member such as a printing medium in a thermal transfer type thermal printer, etc., and in particular, a device for properly feeding out a strip-shaped member such as a printing medium in a thermal transfer type thermal printer. This invention relates to a device for properly feeding out members.

(Prior art) Conventionally, in this type of belt-shaped member feeding device, when the belt-shaped member which is wound and held in a roll around the feeding shaft is fed out, a low drag force is applied to the feeding shaft itself, so that the winding diameter of the band-shaped member changes. This causes a large change in the feeding force, causing various problems such as meandering and wrinkles on the running path of the strip member, and problems with print quality at the printed portion.

(Purpose of the invention) The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an appropriate feeding device for a band-like member that can keep the drawing tension of the band-like member constant.

(Key Points of the Invention) That is, the present invention is a device for properly feeding out a band-like member, in which a tension roller is elastically biased into contact with the outer periphery of a rolled band-like member, and a constant frictional force is applied to the rotation of this roller.

(Embodiment) Next, a case will be described in which an embodiment of the present invention is applied to a feeding device for a thermal transfer carbon ribbon (hereinafter simply referred to as "ribbon") of a thermal transfer type thermal printer.

As shown in FIG. 1, a ribbon 1 wound into a roll is held on a pay-out shaft 2, and the fed-out ribbon 1 passes through guide rollers 3 and 4 and is wound onto a take-up shaft 5. The ribbon 1 is held between the platen 6 and the thermal head 7 along with the label 8 during transportation, and printing is performed according to a predetermined printing signal.

A tension roller 11 attached to a lever 10 rotatably biased by a spring 9 in the direction of the feeding shaft 2 is brought into contact with the outer periphery of the ribbon 1 . A nut 13 and a spring 1 are attached to the rotating shaft 12 of this roller.
4, a washer 15 and a felt material 16 are provided, respectively;
The tension roller 11 is elastically biased in the thrust direction of the rotating shaft 12 and is rotatable with a constant frictional force. A cam 19 that rotates around a shaft 18 is attached near the rotation shaft 17 of the lever 10, and the lever 10 can be moved toward and away from the rolled ribbon 1 by means of an opening/closing knob 20. Next, the effect will be explained.

Along with the printing operation, the ribbon 1 is driven intermittently and is drawn out from the feeding shaft 2 to the printing area between the platen 6 and the thermal head 9, and its winding diameter gradually decreases.

Due to the intermittent drive, the ribbon 1 may become slack due to inertial action when stopped, and the inertial action becomes larger as the winding diameter of the ribbon 1 becomes larger.

However, there is a spring 9 on the outer periphery of the roll of the ribbon 1, in which the biasing force of the spring 9 is large when the winding diameter of the ribbon 1 is large, and conversely, the biasing force of the spring 9 is small when the winding diameter is small. Since the tension roller 11, which is elastically biased by the tension roller 11, is in contact with the tension roller 11, its inertial action is canceled and the tension of the ribbon 1 is kept constant.

Furthermore, the tension roller 11 is not configured to freely rotate, but is supported by a shaft under a constant frictional force, so that the inertial effect is not aggravated.
Since it acts as a back tension relative to the drawing of the ribbon 1, the tension of the ribbon 1 is kept constant from this point as well.

In this embodiment, an example in which the present invention is applied to a thermal transfer type thermal printer has been described, but the present invention can be applied to any printer. Moreover, it can be employed to feed out not only particularly thin carbon ribbons but also any belt-like member such as a roll of label paper.

(Effect of the invention) As described above, according to the present invention, with a simple configuration,
Appropriate printing quality can be expected by keeping the tension applied to a particularly thin band-like member such as a thermal transfer carbon ribbon constant, thereby preventing the band-like member from slipping, meandering, or wrinkling on the transport path.

[Brief explanation of the drawing]

Figure 1 is a schematic explanatory diagram of one embodiment of the present invention;
The figure is a plan view of the main part. Explanation of symbols, 1...Ribbon, 2...Feeding shaft,
3, 4...Guide roller, 5...Take-up shaft, 6...
Platen, 7... Thermal head, 8... Label, 9... Spring, 10... Lever, 11... Tension roller, 12... Rotating shaft, 14... Spring,
16...Felt material, 17...Rotation shaft, 20...
Opening/closing knob.

Claims (1)

[Scope of utility model registration request] A tension roller is elastically biased and brought into contact with the outer periphery of a band-shaped member that is wound and held in a roll around a feeding shaft, and this tension roller is elastically pressed in the thrust direction against the rotating shaft via a spring material. 1. A device for properly feeding out a band-shaped member, characterized in that a constant frictional force is applied to the rotation of the roller.