JPH0320122Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field The present invention relates to an improvement of a paper feeding device in a thermal transfer printer used as a recording device for TSS terminals, word processors, etc.

(b) Conventional technology Paper feeding devices in conventional thermal transfer printers generally use an electromagnetic clutch as a clutch mechanism to connect and disconnect between the main roller shaft and the drive unit, and the structure is complicated and large, and the material Not only are costs and assembly costs high, but maintenance is also increased.

(c) Problems to be solved by the invention The purpose of the invention is to provide a paper feeding device for a thermal transfer printer that reduces the material cost and assembly cost of the above-mentioned conventional products and does not require maintenance. This is an improved clutch mechanism for the paper feeder.

(d) Means for Solving Problems The paper feeding device of the present invention has a clutch mechanism inserted between the main roller shaft, motor drive unit, and manual paper feed rotary knob, which is rotatably connected to the drive unit side. The sleeve is rotatably inserted around one end of the main roller shaft to which the paper feed roller is fixed, and the end of one turn of the coil spring, which is inserted near the end of the main roller shaft, is rotated around the sleeve. It is configured to have a structure that engages in the direction of movement.

(E) Effect According to the above configuration, by appropriately setting the outer diameter of the main roller shaft and the inner diameter of the coil spring, when the drive-side sleeve rotates, the coil A difference in inner diameter occurs due to the "tightening" or "loosening" of the spring, and a clutch action consisting of "sliding" and "frictional engagement" is caused by the relative value of this inner diameter difference and the outer diameter of the main roller shaft. It will come to be carried out.

(F) Embodiment Hereinafter, one embodiment of the paper feeding device in the thermal transfer printer of the present invention will be described with reference to the drawings.
The figure is a partially cutaway front sectional view showing the clutch mechanism, and FIG. 2 is a plan view of the main part in FIG. 1.

As shown in FIG. 3, the device of the present invention is attached to a main roller shaft 2 which is rotatably mounted on bearings 3, 3 provided in a paper delivery section of a thermal transfer printer 1.

A drive gear 5, which is prevented from sliding in the axial direction by retainer rings 4, is rotatably inserted into the first shaft portion 2a formed at one end of the main roller shaft 2, and the sleeve portion 6 is rotatably inserted thereinto. , the sleeve portion 6
In the cylindrical space between the stepped portion 7a formed in the shaft hole 7 and the first shaft portion 2a, there is a coil spring 8 whose outer diameter and free inner diameter of the first shaft portion 2a are the same diameter or slightly smaller.
is positioned and constitutes the first clutch mechanism 10, and one winding end 8a bent in the outer diameter direction projects from a slit locking part 9a extending in the axial direction of the notch 9 formed in the sleeve part 6, It is engaged only in the rotational direction, and the other winding end 8b is located approximately in the center of the width of the notch 9 hole, so that rotational load of the sleeve portion 6 is not applied.

Reference numeral 11 denotes an idle gear that meshes with the drive gear 5. The idle gear 11 is rotatably attached to the drive shaft of a DC motor 12 with a tachometer generator for driving paper feed, and the first clutch mechanism is indicated by the arrow A. Only directional rotation is transmitted.

Reference numeral 13 indicates a boss portion 14 which is connected to the second clutch mechanism 1 with respect to the second shaft portion 2b of the main roller shaft 2.
5, the second clutch mechanism 15 is a rotary knob for manual paper feeding that is pivotally connected via a shaft hole 16 of a boss portion 14 which is rotatably inserted into the second shaft portion 2b.
A coil spring 17 whose outer diameter and free inner diameter are the same or slightly smaller than the outer diameter of the second shaft portion 2b is positioned in the cylindrical space between the stepped portion 16a and the second shaft portion 2b formed in the outer diameter. A notch 18 formed in the boss portion 14 with one winding end 17a bent in the radial direction.
It protrudes from the slit locking part 18a extending in the axial direction of the winding end 1, and engages only in the rotating direction.
Reference numeral 7b is located approximately in the center of the width of the notch 18 hole, and is configured so that no rotational load is applied to the boss portion 14, so that the rotation knob 13 for manual paper feed can only be rotated in the direction of arrow A. It is transmitted to the main roller shaft 2 via the second shaft portion 2b.

In addition, the manual paper feeding rotary knob 13 is located at the boss portion 1.
Spring pressing ring 1 fitted into the end of shaft hole 16 of 4
9 is brought into contact with a coil spring 17 to prevent extraction. Reference numeral 20 denotes a plurality of paper feed rollers which are arranged and shaft-mounted to the main shaft 2 at appropriate intervals.

The paper feeding device of the thermal transfer printer configured as described above is one in which the paper is automatically fed by a DC motor 12 with a tachometer generator for driving the paper in response to an electric signal, and the paper is manually fed by a rotary knob 13 for manual paper feeding. It is.

The first clutch mechanism 10 and the second clutch mechanism 15, which are constructed between the first shaft portion 2a of the main roller shaft 2 and the drive gear 5, and between the second shaft portion 2b and the manual paper feed rotary knob 13, are connected to the fourth clutch mechanism 10 and the second clutch mechanism 15, respectively. As shown in the figure, since the coil springs 8 and 17 inserted onto the shaft parts 2a and 2b are left-handed, the sleeve part 6 of the drive gear 5 or the boss part 14 of the manual paper feed rotary knob 13 is rotated counterclockwise (arrow A). ), the winding ends 8a, 17a engaged with the slit locking portions 9a, 18a are moved in the winding direction of the coil springs 8, 17 with respect to the axial circumference. Therefore, the coil springs 8, 17 are tightly fastened to the shaft portions 2a, 2b in an attempt to deform in a direction to reduce the inner diameter.
Since the sliding resistance increases, the coil spring 8,
The main roller shaft 2 rotates together with the drive gear 5 or the manual paper feed rotary knob 13 via the rotation knob 17, and rotation is transmitted.

On the other hand, when the drive gear 5 or the manual paper feed rotary knob 13 rotates clockwise (arrow B), the winding ends 8a, 17a of the coil springs 8, 17 are engaged with the slit locking portions 9a, 18a, as shown in FIG. is moved in the opposite direction to the winding direction with respect to the shaft circumference, deforms in a direction that enlarges the inner diameter of the coil springs 8 and 17, and slips between the outer circumferences of the shaft portions 2a and 2b, causing the drive gear 5 Or rotary knob 1 for manual paper feed
3 is not transmitted to the main roller shaft 2.

(g) Effects of the invention In the paper feeding device of the thermal transfer printer of the invention, the clutch mechanism constructed between the rotary drive unit side and the main roller shaft relies on a single coil spring that is fitted onto a part of the main roller shaft. Because it is constructed with two parts, the structure of the part is simplified, which not only contributes to lower production costs and downsizing of the equipment, but also
A maintenance-free structure can be obtained, and the practical effects of the present invention are extremely large.

Further, the paper feeding device of the thermal transfer printer of the present invention includes a first clutch mechanism and a second clutch mechanism so as to independently transmit the rotation of the motor drive unit and the manual paper feeding rotary knob to the main roller shaft. Since these are provided separately, there is no need for the rotational movement of one to affect the rotational movement of the other. Therefore, when manually feeding paper using the manual paper feed rotary knob, the manual paper feed rotary knob is free from the motor drive unit, so it is not subjected to the load of the motor drive unit and has a relatively small load. It can be easily operated by force. Furthermore, when paper is automatically fed by the motor drive unit, there is no inconvenience that the rotary knob for manual paper feeding rotates by itself.

[Brief explanation of drawings]

The drawings show one embodiment of the paper feeding device in the thermal transfer printer of the present invention, in which Fig. 1 is a partially cutaway front sectional view of the main part, Fig. 2 is a view taken along the - line in Fig. 1, and Fig. The figure is a schematic plan view of the printer.
4 and 5 are explanations showing the clutch action. 1...Thermal transfer printer, 2...Main roller shaft, 5...Drive gear, 6...Sleeve part,
8, 17... Coil spring, 9, 18... Notch, 10, 15... Clutch mechanism, 11... Idle gear, 12... DC motor with tachometer generator for paper feed drive, 13... Rotation knob for manual paper feed , 14... Boss portion, 20... Paper feed roller.

Claims (1)

[Scope of utility model registration request] In a paper feeding device for a thermal transfer printer, in which a large number of paper feeding rollers are disposed on a rotatably rotatable main roller shaft, and the paper is fed by sliding contact of the paper feeding rollers, the main roller shaft and a motor drive unit are used. A sleeve rotatably connected to the drive unit side is rotatably inserted into a part of the main roller shaft, and a rotary knob for manual paper feed is rotatably inserted into a part of the main roller shaft with respect to the sleeve. The end of the inserted coil spring is connected via a first clutch mechanism that engages in the rotational direction, and the boss of the rotary knob for manual paper feeding is rotatably attached to the end of the main roller shaft. The main roller shaft is connected to the boss through a second clutch mechanism that engages in the rotating direction an end of one turn of a coil spring that is externally inserted into a part of the main roller shaft. Paper feeding device for thermal transfer printers.