JPH0939346A - Ink ribbon cassette - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the deformation of a coil spring caused by the tension of an ink ribbon acting on a stock core in an ink ribbon cassette constituted so as to apply elastic energizing force to the stock core by the coil spring to avoid the cause of printing inferiority. SOLUTION: The support part 4 supporting a stock core 5 to a case main body is constituted of the support shaft part 51 integrally formed to the case main body, the slide contact member 52 provided to the support shaft part 51 in a freely relatively movable manner in the axial direction thereof and in a non-rotatable state in the rotary direction thereof and the coil spring 53 elastically pressing and energizing the slide contact member 52 toward the stock core 5.

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 to be used in a printer device such as a thermal transfer printer having a printing ink supply means using a cassette type ink ribbon.

[0002]

2. Description of the Related Art Conventionally, in this type of ink ribbon cassette, a coil spring is directly attached to a stock core holding an ink ribbon in a wound state, in the axial direction thereof.
Alternatively, it is configured to indirectly apply the force through a sliding contact member as disclosed in Japanese Utility Model Laid-Open No. 61-47660 to exert an elastic biasing force to give a resistance to the rotation of the stock core. By applying the biasing force of the coil spring in this way, the rotational resistance (or brake torque) is directly applied to the stock core to which the rotational force is applied through the ink ribbon drawn by the rotationally driven winding core. Will be given.
Therefore, at the time of use (at the time of printing), a predetermined tension can be applied to the ink ribbon pulled out from the stock core to the take-up core side, and further, at the time of transportation,
This is useful in that it is possible to suppress the careless feeding of the ink ribbon due to the rotation of the stock core due to vibration or the like.

[0003]

However, in the conventional structure described above, since the coil spring is simply pressed against the end face of the stock core, a predetermined rotation resistance should be given to the stock core by using the coil spring. Then, regardless of whether the pressure contact between the two is direct or indirect, as a reaction force thereof, the rotational force on the stock core side acts on the coil spring side. When this rotating force on the stock core side is transmitted to the coil spring, the coil spring is gradually deformed in its rotating direction, and the reaction force due to the deformation is the tension of the ink ribbon and the acting force of the coil spring in the reverse rotating direction. Gradually increases. When the magnitude of the acting force in the reverse rotation direction exceeds the frictional force at the pressure contact point between the stock core and the coil spring, slippage occurs at the pressure contact point, and the deformation of the coil spring is instantaneously eliminated. , The stock core receives a strong pulling action of the ink ribbon, and the ink ribbon is momentarily pulled out in an opposite direction to the return direction of the coil spring, causing slack in the ink ribbon, which is a cause of defective printing. There was a chance To solve such a problem, it is conceivable to use a disc spring that does not deform in the rotation direction as the biasing means of the stock core without using the coil spring as described above. There is another problem like. In other words, since the normal disc spring has a large amount of change in spring pressure with respect to its displacement, it is easily susceptible to a slight difference in processing accuracy or mounting error on the case body, stock core side, or disc spring itself. Therefore, the variation in the elastic urging force is large as compared with the case where the coil spring is used. In the present invention, such a problem of the conventional technique is solved, and in the one in which the coil core is used to apply the elastic biasing force to the stock core, the deformation of the coil spring due to the tension of the ink ribbon acting on the stock core is prevented. This is intended to suppress and prevent the cause of print defects.

[0004]

In order to solve the above-mentioned problems, according to a first aspect of the present invention, a coil spring for urging a stock core by a frictional force in the direction of rotation generated as the stock core rotates. Is provided to prevent the coil spring from being twisted. Therefore, the coil spring applies only the pressing force in the axial direction to the stock core side, and the frictional force in the rotation direction generated as the stock core rotates can be prevented from acting on the coil spring. As a result, changes in the elastic biasing force in the axial direction and the frictional force in the rotating direction are reduced, and a stable predetermined rotational resistance acts between the coil spring side and the stock core side. Further, as described in claim 2, a bearing portion that supports the stock core with respect to the case body is provided with a spindle portion integrally formed with the case body, and the bearing portion is axially opposed to the spindle portion. A means may be adopted which is composed of a sliding contact member that is movably mounted in a rotation stop state in the rotation direction and the coil spring that elastically biases the sliding contact member toward the stock core. Good. By adopting this means, the rotation of the sliding contact member prevents the elastic predetermined force in the axial direction and the change in the frictional force in the rotation direction from changing, as in the case of the means described in claim 1. Rotational resistance acts between the coil spring side and the stock core side. Further, as described in claim 3, in constructing the support shaft portion, a detent locking portion for restricting the position of the sliding contact member in a detent state is provided, and the detent locking is provided. The portion may be provided with a retaining engagement portion for preventing the sliding contact member from slipping out in the axial direction. In this case, the support shaft portion as means for regulating the position of the sliding contact member is slidably contacted. It can also be used as a means for preventing the members from coming off, and also makes it possible to prevent the coil springs from coming off.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Next, preferred embodiments of the present invention will be described. As shown in FIGS. 1 and 2, the ink ribbon cassette of the present invention includes a case body 1 which can be divided into an upper case 2 and a lower case 3, and a case body 1 thereof.
Stock cores 5 rotatably supported on bearing parts 4 of the
And a combination with the winding core 6. The stock core 5 is a roll of the ink ribbon 7 before use, and the take-up core 6 is wound up from the stock core 5 and takes up the ink ribbon 7 that has passed the print head position of the printer. It is configured as follows.

The case body 1 has bearings 4 for the cores 5 and 6 formed on the upper case 2 side and the lower case 3 side, respectively.
Is divided into upper and lower parts by a dividing surface that crosses substantially the central portion in the axial direction, and both cases 2 and 3 are configured to be engageable with and disengageable from each other by fitting a pin and a pin hole formed on the dividing surface. There is.

The bearing portion 4 of the lower case 3 on the side supporting the winding core 6 has a driving support shaft 41 which is integrally rotatable with the winding core 6 and a lower side shaft end thereof. It is configured with a winding gear 42 provided integrally.
Then, the drive support shaft 41 is provided with a spline portion that engages with a spline groove formed in the winding cylinder 61 of the winding core 6 on the outer periphery and is inserted into the winding cylinder 61 by It is mounted so as to be rotatable relative to the lower case 3 so as to transmit a driving force from a printer device (not shown). Of the bearing portions 4 of the winding core 6, the one on the side of the upper case 2 is formed in a cylindrical bearing portion 4 integrally formed with the upper case 2, and the pair of upper and lower bearing portions 4 and 4 form a pair. The winding core 6 is rotatably supported.

On the side that supports the stock core 5, the bearing portions 4 of the upper case 2 and the lower case 3 respectively.
Is configured as shown in FIGS. That is, each of the casings 2 and 3 is provided with split cylinder-shaped support shaft portions 51 and 51 integrally formed with each of the cases 2 and 3, and each support shaft portion 51 is provided.
The slide contact member 52 that contacts the end surface of the stock core 5 is inserted into the above, and the slide contact member 52 is inserted between the case inner surface on the lower case 3 side and the slide contact member 52.
A coil spring 53 that elastically biases to the side is attached.

Further, the split cylindrical support shaft portion 51 is provided with a detent locking portion 54 composed of a split groove, and a guide inclined surface 55 is provided on the split groove inlet side of the detent locking portion 54. , And a retaining engagement portion 56 including a locking step portion that partially narrows the groove width. On the other hand, the sliding contact member 52 is
Locking projection 5 that projects radially inward on the inner peripheral surface side
7 is integrally provided, and by engaging the locking projection 57 with the rotation stopping locking portion 54 of the split cylindrical support shaft portion 51, the support shaft portion 51 and the sliding contact member 52 are prevented from coming off. It is configured to fit in the state. Further, when the support shaft portion 51 and the sliding contact member 52 are fitted to each other in this retaining state, the circumferential width w1 of the locking projection 57 is about the same as the groove width w2 of the rotation locking portion 54. Since both are set,
The stock core 5 moves relatively in the axial direction but does not move in the circumferential direction, that is, in the rotation direction. Therefore, the sliding contact member 52 is locked to the support shaft portion 51 integrally formed with each of the cases 2 and 3, so that the stock core 5 is not locked.
Is mounted in a state in which the rotation around the rotation axis of the is stopped. As a result, the frictional force in the rotation direction generated between the stock core 5 and the sliding contact member 52 due to the rotation of the stock core 5 is not transmitted as a force for twisting the coil spring 53 therebelow. In addition, in FIG. 1, reference numeral 31 indicates
This is a viewing window provided in the lower case 3, and the remaining amount of the ink ribbon 7 wound around the stock core 5 can be visually confirmed from the outside.

[Other Embodiments] The present invention can be implemented in various forms other than the above-mentioned embodiment,
The example will be further described.

As shown in FIG. 7, in constructing the sliding contact member 52, the spring receiving surface for the coil spring 53 is provided between the sliding contact surface and the stock core 5 so as to enter the inside of the stock core 5. You may provide a level difference in. By doing so, the axial length of the case body 1 can be shortened relative to the axial length of the coil spring 53.

As a means for preventing the frictional force caused by the rotation of the stock core 5 from being transmitted as the action of twisting the coil spring 53, the sliding member 52 mounted in the rotation-stop state as in the above-described embodiment is used. The configuration is not limited to the one used, and may be configured as follows. That is, both ends of the coil spring 53 are bent inward in the radial direction to form a hook portion, and the hook portion is formed by the support shaft portion 5.
Like the detent locking portion 54 of No. 1, it is engaged with a portion that allows movement in the axial direction but prevents movement in the rotation direction,
The stock core may be expanded and contracted in the axial direction but may not be relatively rotated.

The case body 1 is not limited to the one constituted by the divided body of the upper case 2 and the lower case 3 as shown in the above-mentioned embodiment, but the whole case body 1 is constituted by one body. May be.

The support shaft portion 51 provided on the case body 1
Is not limited to one integrally molded with the case body 1, but is manufactured separately from the case body 1 and integrated with the case body 1 by an appropriate means such as adhesion, welding, fitting, screwing, or the like. May be

One end of the coil spring 53 may be integrally provided with the sliding contact member 52. With this configuration, the coil spring 53 can be attached as the sliding contact member 52 is fitted into the support shaft portion 51, which is effective in reducing the number of processing steps.

The sliding contact member 5 on the stock core 5 side
The engagement between the shaft 2 and the support shaft portion 51 is not limited to the engagement between the detent locking portion 54 and the locking protrusion 57 on the sliding contact member 52 side using the above-mentioned split groove, but by a spline or a key. Mating,
Alternatively, the shaft portion serving as the support shaft portion 51 has a different diameter cross section, and the fitting portion of the sliding contact member 52 is a different diameter hole having the same shape.
Any structure may be adopted as long as the structure allows the relative movement of the two in the axial direction but prevents the relative rotation.

[0017]

EXAMPLES The ink ribbon cassette of the present invention is carried out as follows. As shown in FIGS. 1, 3 and 4,
The take-up gear 42 is mounted so as to mesh with the transmission gear 8 on the printer device side, and is rotationally driven by receiving rotative power in one direction. At that time, it is necessary to prevent the take-up core 6 from rotating in the reverse direction. The ratchet that rotates the winding core 6 only in one direction by the claw portion 62 formed on the outer peripheral portion of the winding cylinder 61 of the winding core 6 and the stopper 63 made of a leaf spring mounted on the lower case 3 side. It constitutes the mechanism.

Then, when the ink ribbon cassette of the present invention is mounted on the printer device and printing is performed at the print head position, the ink ribbon 7 fed from the stock core 5 is used.
Is configured such that a predetermined tension is applied by the frictional force of the sliding contact member pressed by the coil spring 53. Further, when the ink ribbon cassette is not attached to the printer device, the stock core 5 does not rotate carelessly due to the frictional force.

In constructing this ink ribbon cassette, the case body 1 is made of a thermoplastic resin such as ABS, PS, PP or the like, and the stock core 5 and the winding core 6 are
The sliding contact member 52 is made of S, ABS, POM, vinyl chloride resin, paper tube, or the like, and the sliding contact member 52 has a sliding property such as POM (polyacetal), lubricant containing resin such as oil, silicon, molybdenum, or fluorine, or PA. Made of good material.
The coil spring 53 is made of SUS, piano wire or spring steel having a required elastic biasing force.

[0020]

As described above, according to the first aspect of the present invention, the coil spring is used to apply the elastic biasing force to the stock core, but the stock core is rotated. Since it is possible to avoid the accompanying frictional force from deforming the coil spring in the rotational direction, it is possible to avoid the occurrence of defective printing due to the deformation of the coil spring. The invention according to claim 2 is
By the rotation stop of the sliding contact member, the same effect as that of the invention according to claim 1 can be obtained. Furthermore, the invention according to claim 3 reduces the number of parts by using the support shaft portion as means for restricting the position of the sliding contact member also as means for preventing the sliding contact member and the coil spring from coming off. There is an advantage that can be achieved.

It should be noted that reference numerals are given in the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a partial front sectional view showing the whole.

FIG. 2 is a plan view showing the whole

FIG. 3 is a bottom view showing the whole

FIG. 4 is a partially enlarged perspective view showing a drive unit of a winding core.

FIG. 5 is a sectional view showing a stock core portion.

FIG. 6 is a perspective view of components of a bearing portion of the stock core.

FIG. 7 is a cross-sectional view showing another embodiment of the bearing portion of the stock core.

[Explanation of symbols]

 1 Case Main Body 2 Upper Case 3 Lower Case 4 Bearing Part 5 Stock Core 6 Winding Core 7 Ink Ribbon 53 Coil Spring 51 Spindle Part 52 Sliding Contact Member 54 Rotation Stopper Locking Part 56 Locking Engagement Part

Claims (3)

[Claims] 1. A stock core (5) holding an ink ribbon (7) in a wound state is pressed and urged in the rotational axis direction by an elastic urging force of a coil spring (53), and the stock core (5) An ink ribbon cassette rotatably mounted on a case body (1) while giving resistance to rotation, wherein a frictional force in a rotational direction generated as the stock core (5) rotates is generated by the stock core (5). An ink ribbon cassette which is prevented from acting on the coil spring (53) for pressing and biasing the coil spring (53) so that the coil spring (53) is not twisted. 2. A stock core (5) holding an ink ribbon (7) in a wound state is pressed and urged in the direction of the rotation axis by an elastic urging force of a coil spring (53). An ink ribbon cassette rotatably mounted on a case body (1) while giving resistance to rotation, comprising a bearing portion (4) for supporting the stock core (5) with respect to the case body (1). A support shaft portion (51) formed integrally with the main body (1) and the support shaft portion (5
Sliding member (52) mounted so as to be relatively movable in the axial direction with respect to 1) and in a rotation stop state in the rotating direction.
And an coil ribbon (53) for elastically urging the sliding contact member (52) toward the stock core (5). 3. The support shaft portion (51) is provided with the sliding contact member (5).
2) A detent locking portion (54) for restricting the position of the detent in a detent state, and the detent locking portion (54)
The ink ribbon cassette according to claim 2, further comprising a retaining engagement portion (56) for preventing the sliding contact member (52) from being detached in the axial direction.