JPH08276630A - Ink ribbon cassett - Google Patents

Abstract

PURPOSE: To provide an ink ribbon cassette which can completely prevent an ink ribbon from sagging by regulating the rotation of a spool at an optional position. CONSTITUTION: Spools 2a, 2b are engaged in cassette main bodies 1a, 1b freely movably in the axial direction. A compression coil spring is installed which pushes spools 2a, 2b elastically to one end side to the other end side of the spools 2a, 2b. A ring-shaped recessed groove part 28 is formed in the end surface part on one end side of the spools 2a, 2b. A projection part 18 which is freely bondable/separable to/from the groove part 28 by the movement of the spools 2a, 2b in the axial direction is projected in the axial direction from the end part of main bodies 1a, 1b opposite to the groove part 28 of the spools 2a, 2b toward the groove part 28. When a cassette is removed from a thermal transfer printer, force in the axial direction which has acted upon the spools 2a, 2b from the printer side is eliminated so that the spools 2a, 2b are moved in the axial direction by a spring. Consequently, the groove part 28 of the spools 2a, 2b is bonded to the projection part 18 of the cassette main bodies, regulating the rotation of the spools 2a, 2b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink ribbon cassette of a thermal transfer printer which transfers ink of an ink ribbon onto a recording medium by using a thermal head, and is characterized by an ink ribbon slack preventing structure. .

[0002]

2. Description of the Related Art A thermal transfer printer using a thermal head stores an ink ribbon in a cassette to facilitate replacement. In such an ink ribbon cassette, the spool around which the ink ribbon is wound can freely rotate when it is attached to or detached from the thermal transfer printer or when it is left alone, so that the ink ribbon is likely to loosen. To prevent this, various slack prevention structures have been proposed.

For example, JP-B-4-44375, JP-A-5-155122, and JP-A-5-305745.
As disclosed in Japanese Patent Laid-Open No. 5-330180 and Japanese Unexamined Patent Publication No. 5-330180, a plurality of concave portions are provided at a constant pitch on a peripheral side wall or an end surface of a spool, and convex portions or claws are provided on a case body side. Alternatively, it is intended to prevent the ribbon from loosening by engaging with the claws to regulate the rotation of the spool.

[0004]

However, in any of these conventional slack prevention structures, the spool is prevented from rotating unless one of the recesses of the spool is rotated to a position where it engages with a protrusion or a claw on the case body side. Since it cannot be regulated, a slight slack of the ink ribbon is unacceptable in this respect.

The present invention has been made in view of the above circumstances, and an object thereof is to completely prevent the slack of the ink ribbon by allowing the rotation of the spool to be restricted at an arbitrary position. is there.

[0006]

According to a first aspect of the present invention, a pair of spools are rotatably fitted in both sides via ink ribbon moving windows opened in a cassette body,
In an ink ribbon cassette that winds the ink ribbon wound on one spool on the other spool, it is provided for one end side of the spool that is axially movably fitted in the cassette body, and the spool is elastic toward the other end side. Elastic pressing portion that presses dynamically, an annular groove portion provided on the end surface portion on the other end side of the spool, and a shaft extending from the end portion of the cassette body facing the groove portion of the spool toward the groove portion. The ink ribbon cassette is configured to have a concave groove portion and an engagement / disengagement protrusion portion that are provided so as to protrude in a direction and are axially moved.

According to a second aspect of the present invention, in the ink ribbon cassette according to the first aspect, a flat plate-shaped protrusion is detachably provided in the annular groove.

[0008]

In the invention described in claim 1, when the cassette body is taken out from the thermal transfer printer, the axial force acting on the spool from the thermal transfer printer side is released, and the elastic pressing portion in the cassette body causes The spool moves in the axial direction. As a result, the annular recessed groove portion provided on the end surface portion of the spool and the protrusion protruding from the end portion of the cassette body toward the recessed groove portion engage with each other, and the rotation of the spool is restricted.

According to a second aspect of the present invention, the flat plate-like projection portion relatively inserted into the annular groove portion engages with both right and left side portions thereof on the outer diameter side peripheral wall surface of the groove portion. , Its central portion engages with the inner peripheral wall surface of the concave groove portion.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to an embodiment shown in FIGS.

As shown in FIG. 1, the cassette main body 1a on one side and the cassette main body 1b on the other side respectively have a pair of semi-cylindrical spool accommodating portions 11a, 12a and spool accommodating portions 11b, 12b. , The connecting portions 13a at their both ends,
It is integrally molded with 13b.

Semi-cylindrical spool accommodating portions 11a and 12a and spool accommodating portions 11b and 12b of the cassette bodies 1a and 1b.
By joining and integrating, a pair of cylindrical spool storage parts 11,
These cylindrical spool compartments together with 12 forming
An ink ribbon moving window 14 is formed between 11 and 12.

When joining the cassette bodies 1a and 1b on one side and the other side, a pair of spools 2a and 2b are rotatably fitted in the spool housing portions on both sides. One spool is formed by winding an ink ribbon (not shown), and the other spool is wound by the rotation of the thermal transfer printer.

As shown in FIG. 2, the spool 2a,
In 2b, the lower end side of the hollow rotating shaft 21 is used as a spring fitting portion 22, and a spring receiving flange portion 23 is integrally formed inside the spring fitting portion 22 in the axial direction.

Further, a cylindrical rotation transmitting portion 24 is integrally formed on the upper end side of the rotating shaft 21, and a plurality of spools for transmitting the rotation given by the thermal transfer printer to the inner peripheral surface of the rotation transmitting portion 24. The drive rib 25 is integrally molded.

Further, a concave groove portion forming flange portion 26 is integrally formed on the inner side of the rotation transmitting portion 24 in the axial direction, and a cylindrical portion 27 is formed concentrically on the axial upper side of the outer peripheral edge of the flange portion 26. As a result, an annular recessed groove portion 28 as shown in FIG. 3 is provided on the inner peripheral side of the cylindrical portion 27.

The spring fitting portions 22 of the spools 2a and 2b are
After the compression coil springs 3a and 3b as elastically pressing portions are fitted, the U-shaped groove 16 of the bearing plate portion 15 integrally formed with the spool housing portions 11a and 12a on one side is rotatable and axially movable. Fit in. The compression coil springs 3a and 3b are between the bearing plate portion 15 and the spring receiving flange portion 23 and elastically press the spools 2a and 2b upward in FIG.

The rotation transmitting portion 24 of the spools 2a and 2b is a cassette body integrally formed on the upper ends of the spool housing portions 11 and 12.
The end plates 17 of 1a and 1b are rotatably and axially movable in circular holes.

The end face plate portions 17 of the cassette bodies 1a and 1b are located at positions facing the cylindrical portions 27 of the spools 2a and 2b, and the pair of protrusions 18 are directed from the inner side surface of the end face plate portions 17 to the concave groove portions 28. Integrally molded so as to project in the axial direction.

The projection 18 is formed in a flat plate shape as a whole as shown in FIG. 1 (A), but as shown in FIG. 1 (B).
The side surface shape shown in the cutout window 19 shown in FIG. 3 is formed in a wedge shape, and is relatively engaged with and disengaged from the concave groove portion 28 by the axial movement of the spools 2a and 2b.

In FIG. 1B, the spool 2a on the left side shows a state in which this cassette is mounted in the thermal transfer printer,
The spool 2b on the right side shows a state in which this cassette is taken out from the thermal transfer printer.

Next, the operation of this embodiment will be described. When this ink ribbon cassette is installed in the thermal transfer printer, as shown in FIG. 2 (A), the spools 2a, 2b
On the other hand, an axial force acts downward from the thermal transfer printer side, and the concave groove portions 28 of the spools 2a and 2b are disengaged from the lower side of the projection portion 18 on the cassette body side. Therefore, the spools 2a and 2b can freely rotate.

On the other hand, when the ink ribbon cassette is taken out from the thermal transfer printer, the axial force acting downward on the spools 2a and 2b from the thermal transfer printer side is released, and the spool is moved as shown in FIG. 2 (B). The compression coil springs 3a and 3b in the cassette bodies 1a and 1b cause the 2a and 2b to return and move upward in the axial direction.

As a result, the annular recessed groove portion 28 provided on the upper end surface portions of the spools 2a and 2b engages with the projection portion 18 projecting from the upper end portions of the cassette bodies 1a and 1b toward the recessed groove portion 28. ,
The rotation of the spools 2a and 2b is restricted.

In particular, in the flat plate-like projection 18 relatively inserted into the annular groove 28, the left and right side portions formed in a wedge shape are the outer peripheral side wall surface of the groove 28, that is, the cylindrical portion 27. It engages with the inner peripheral surface by biting, and the center portion engages with the inner peripheral surface of the concave groove portion 28, that is, the outer peripheral surface of the rotation transmitting portion 24.

As described above, the spools 2a, 2b are always fixed in the axial direction by the spring pressure, and engage with the protrusions 18 at arbitrary positions in the rotation direction, so that the rotation is surely restricted. It is possible to reliably prevent the slack of the ink sheet.

In this embodiment, the compression coil springs 3a and 3b are used as the elastic pressing portions, and the spools 2a and 2b are pressed by the springs in the axial direction. However, elastic members other than such springs are used. For example, resin springs that substitute for the springs 3a and 3b may be integrally formed on the cassette bodies 1a and 1b made of synthetic resin. Alternatively, it may be molded separately.

[0028]

According to the first aspect of the present invention, the annular groove is provided on the spool side, and the projection is provided in the axial direction from the cassette body side toward the groove to provide the elastic pressing portion. The axial movement of the spool causes the concave groove and the protrusion to engage, so if the axial force acting on the spool is released by, for example, removing the ink ribbon cassette from the thermal transfer printer, the spool becomes elastic. By the return movement in the axial direction by the pressing part, the spool rotation can be regulated at any position by the engagement between the arbitrary part of the groove on the spool side and the axial protrusion on the cassette body side, and the slack of the ink ribbon can be prevented. Can be completely prevented. Further, the ribbon slack can be prevented by the extremely simple structure of the axial projection portion of the cassette body and the concave groove portion of the spool, and they can be easily manufactured and provided at low cost.

According to the second aspect of the present invention, since the flat plate-shaped projection is provided so as to be engageable with and disengageable from the ring-shaped recessed groove, the flat-plate-shaped projection relatively inserted into the ring-shaped recessed groove. The part engages with the peripheral wall surface of the concave groove part at the left and right side parts and the central part, and the rotation of the spool can be reliably regulated.

[Brief description of drawings]

FIG. 1A is a plan view showing an embodiment of an ink ribbon cassette according to the present invention, and FIG. 1B is a front view thereof.

2A is a sectional view taken along the line IIA-IIA in FIG.
FIG. 1B is a sectional view taken along line IIB-IIB in FIG.

FIG. 3 is a plan view showing a spool of the cassette according to the present invention.

[Explanation of symbols]

 1a, 1b Cassette body 2a, 2b Spool 3a, 3b Compression coil spring as elastic pressing part 14 Ink ribbon moving window 18 Projection part 28 Concave groove part

Claims (2)

[Claims] 1. An ink ribbon cover in which a pair of spools are rotatably fitted in both sides via an ink ribbon moving window opened in a cassette body, and an ink ribbon wound on one spool is wound on another spool. In a set, an elastic pressing portion that is provided on one end side of a spool that is axially movably fitted in the cassette body and that elastically presses the spool toward the other end side, and an end surface on the other end side of the spool -Shaped concave groove portion provided in the portion, and axially protruding from the end of the cassette body facing the concave groove portion of the spool toward the concave groove portion, and can be engaged with and disengaged from the concave groove portion by axial movement of the spool And an ink ribbon cassette. 2. The ink ribbon cassette according to claim 1, wherein a flat plate-shaped projection is provided so as to be engageable with and disengageable from the annular groove.