JPH0444883A - Ribbon cassette for printing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a ribbon cassette used in a printing device,
In particular, the present invention relates to a technique for fixing the cassette to the cassette mounting section.

<Prior Art> Ribbon cassettes are often used in printing devices such as typewriters and word processors. Generally, this holds a printing ribbon for printing, and the printing device is provided with a cassette mounting section into which a ribbon cassette is mounted. In this type of printing device, a ribbon drive shaft provided in a cassette mounting section concentrically engages with a driven shaft provided in a ribbon cassette, thereby transmitting rotational force to the driven shaft. There is something. for example,
With carbon ribbon, when the ribbon cassette is attached to the cassette mounting section, the internal gear of the ribbon feed shaft (driven shaft) of the ribbon cassette is connected to the external gear of the take-up drive shaft (ribbon drive shaft) on the printer side. The ribbon is stuck in place, and the ribbon is wound up as printing progresses.

<Problems to be Solved by the Invention> Conventionally, in order to prevent the ribbon cassette mounted on the cassette mounting part of a printing device from lifting up from the cassette mounting part, an elastic fixing means (presser foot) has been attached to the cassette mounting part. (claws, presser mechanism, etc.) had to be added. Furthermore, even if such a presser claw is used, it is not always sufficient to prevent the ribbon cassette from lifting up, and if the ribbon cassette lifts from the cassette mounting section, the ribbon drive shaft on the printing device side and the cassette side The mesh with the driven shaft becomes disengaged, causing problems in ribbon feeding.

An object of the present invention is to provide a ribbon cassette that can be prevented from lifting from the cassette mounting portion without relying on a presser claw or the like. The subject is

Measures taken to solve this problem The following measures were taken to solve this problem. The ribbon feed shaft is formed with inclined teeth that are inclined with respect to a plane that includes the axis thereof, and these teeth can mesh with inclined teeth formed on the ribbon drive shaft on the printing device side. Further, the direction of the inclination of the inclined teeth of the ribbon feed shaft is set in such a direction that the ribbon cassette receives a component force in a direction in which the ribbon cassette is pressed against the cassette mounting portion when the ribbon drive shaft rotates in the ribbon feed direction in the meshed state. has been done.

Regarding the ribbons in the ribbon cassette, for example, in addition to the right-end ribbon that is wound up from the supply spool in the ribbon cassette to the take-up spool in accordance with the printing pitch, such as a thermal ribbon, there is also an endless ribbon that is wound inside the cassette in a meandering shape. It also includes ribbons that are stored and cycled repeatedly.

Further, the ribbon cassette is not limited to a printing ribbon cassette, but also includes an erasing ribbon cassette.

Further, the inclined teeth of the ribbon feed shaft may be internal teeth, external teeth, or end teeth, and the invention does not necessarily require a plurality of inclined teeth.

Functions and Effects> When such a ribbon cassette is installed in the cassette mounting portion of the printing device, the inclined teeth formed on the ribbon feed shaft engage with the inclined teeth of the ribbon drive shaft on the printing device side. When the ribbon feed shaft is rotationally driven by the ribbon drive shaft, a component force is applied to the ribbon feed shaft that causes a ribbon feed motion around its center line due to the meshing of the inclined teeth.
A force component is generated in a direction parallel to the center line in a direction that causes the ribbon feed shaft to approach the cassette mounting portion.

As a result, the ribbon cassette is prevented from floating up from the cassette mounting section, and the ribbon can be fed smoothly. Since the inclined teeth prevent the ribbon cassette from floating up, it is possible to omit fixing means such as a presser claw and a presser mechanism, which were required in the past. Further, by using such a fixing means in combination with the present invention, lifting of the ribbon cassette can be more reliably prevented, and the reliability of ribbon feeding can be improved.

This is an exploded view of the cartridge and the cassette mounting section of the printing device to which it is installed. In the figure, reference numeral 10 denotes a carriage, which is equipped with a printing hammer, a type wheel, etc. (not shown), and is moved back and forth along the printing line. carriage 10
A ribbon vibrator 12 is attached to the ribbon vibrator 12 so as to be able to spread around one axis in the vertical direction, and a ribbon cassette 16 that accommodates the printing ribbon 14 is attached thereto. Note that an erasing ribbon 18 is also attached to the ribbon vibrator 12 and is adapted to be wound from a supply spool 20 onto a take-up spool 22. The ribbon vibrator 12 is always urged upward by a torsion spring 24, but it is moved up and down by a ribbon lift cam (not shown), and the printing ribbon 14 is moved up and down by a ribbon lift cam (not shown).
is selectively positioned at a print position opposite to the print line, and at an erase position where the erase ribbon 18 is opposed to the print line. The erasing ribbon 18 is taken up by the lever 25 driving the ratchet wheel 26 when the ribbon vibrator 12 moves down from the erasing position, and on the supply spool 20 side, the ribbon is pulled out by the slack prevention device 28. resistance is given.

The printing ribbon 14 is wound up by a ribbon winding motor (not shown). The ribbon vibrator 12 has a lever 30 that swings in a certain angle range with the A end as a fulcrum, and a tension spring 3
2, which is biased in one direction by a cam (
(both are not shown), and a ratchet wheel 34 is intermittently driven via a lever 33 for each printing. The ratchet wheel 34 is prevented from reversing by a claw metal fitting 36, and the ribbon drive shaft 3
8 are integrally connected via a shaft holder 40. The ribbon drive shaft 38 is rotatably mounted in a shaft hole 42 formed in the ribbon vibrator 12 in an upright position.

The ribbon drive shaft 38 has a flange 46 in its middle portion, which is rotatably seated on the upper opening surface of the shaft hole 42, and a portion below this flange 46 is provided with a plurality of radial protrusions 48 formed therein. , is connected to the shaft holder 40 in a relatively non-rotatable manner. Further, a spiral gear 50 for driving the ribbon is formed in the upper part of the flange 46. This functions as an inclined tooth of the external tooth of the ribbon drive shaft 38.

On the other hand, as shown in FIG. 3, the ribbon cassette 16 includes a supply spool 62 and a take-up spool 64 inside a cassette case 60, as is well known, and the supply spool 62 revolves around a shaft 66 fixed to the case 60. The take-up spool 64 has a shaft, the center of which is movable within the cassette case 60. An unused printing ribbon 14 is wound around the supply spool 62, and is pulled out in the P direction while being prevented from loosening by passing through the tip of a torsion spring 68, and is then transferred to the take-up spool 64 after use.
leading to. The take-up spool 64 is caused by torsion springs 70 and 72 to displace the center position along an arc centered on point B as the diameter increases as the take-up progresses. 64 to ensure tight winding.

The take-up spool 64 is rotated by a ribbon feed shaft 74 as a driven shaft relative to the ribbon drive shaft 38 . The ribbon feed shaft 74 is rotatably provided at a fixed position in the cassette case 60, and is brought into frictional contact with the take-up spool 64 via the print ribbon 14 under a predetermined pressure mainly due to the elastic force of the torsion spring 70. Ribbon feed shaft 74
The rotation in the counterclockwise direction in FIG. 3 applies a winding rotational force in the clockwise direction in the figure to the take-up spool 64.

As can be seen from FIG. 1A, the ribbon feed shaft 74 has an internally toothed helical gear 76 as a beveled tooth. This helical gear 76 has a plurality of internal tooth lines formed along a spiral line with its axis as its center line, and its helical angle is preferably about 5 degrees with respect to the axis, for example. Note that if this value is too small, the effect of the present invention will be weak;
If it's too big, it will be troublesome to put on and take off. The ribbon feeding direction of the ribbon feeding shaft 74 and the rotational driving direction of the ribbon driving shaft 38 are as follows:
It is counterclockwise (counterclockwise) when viewed from above in Figure 1A,
The direction of twist (inclination) of the helical gear 76 is determined by the first direction.
It is said to follow the Tsurumaki line in a clockwise direction when viewed from above in Figure A.

The same applies to the helical gear 50 of the ribbon drive shaft 38, and both helical gears 76 and 50 are formed with the same pitch, module, and helix angle so that they mesh with each other with internal and external teeth. There is.

Next, the operation of this embodiment will be explained.

When the ribbon cassette 16 is attached to the ribbon vibrator 12 shown in FIG. It is meshed with a spiral gear 50 having external teeth. When the ribbon drive shaft 38 is rotated to take up the ribbon in this state, as shown in FIG.
0,76), the ribbon feed shaft 74 receives a diagonally downward transmission force F perpendicular to the gear surface from the helical gear 50 of the ribbon drive shaft 38. This transmission force F is composed of a horizontal component Fl that rotates the ribbon feed shaft 74 and a horizontal component Fl that rotates the ribbon cassette 7.
It can be divided into a vertical component F2 which suppresses 4. The horizontal component F1 fulfills the ribbon feeding function, and the downward vertical component F2 prevents the ribbon cassette 16 from floating up from the ribbon vibrator 12, improving the reliability of winding the printing ribbon 14.

[Brief explanation of the drawing]

FIG. 1A is a front view simply showing a ribbon cassette and its surroundings as an embodiment of the present invention, FIG. 1B is an explanatory diagram of its operation, and FIG. 2 shows the portion corresponding to FIG. 3 is a partially cutaway plan view of the ribbon cassette, and FIG. 4 is a partially cutaway front view of the ribbon cassette. 12: Ribbon vibrator 16: Ribbon cassette 38: Ribbon drive shaft 50: Helical gear (inclined teeth) 74: Ribbon feed shaft 76: Spiral gear (inclined teeth) Applicant Brother Industries, Ltd. Agent Patent attorney Fuhiko Okada ( 3 people outside) Figure A 1st! IB 7

Claims (1)

[Claims] A ribbon feeding shaft is provided, and when the ribbon feeding shaft is installed in the cassette mounting portion of the printing device, the ribbon is concentrically engaged with a ribbon drive shaft provided in the cassette mounting portion. In a ribbon cassette that receives rotational force for feeding the ribbon from a drive shaft, the ribbon feed shaft is formed with inclined teeth that are inclined with respect to a plane that includes the axis thereof, and the inclined teeth formed on the ribbon drive shaft are and the direction of the inclination of the inclined teeth of the ribbon feed shaft is in the direction in which the ribbon cassette is pressed against the cassette mounting portion when the ribbon drive shaft rotates in the ribbon feed direction in the meshed state. A ribbon cassette for printing devices that is oriented to receive the component force.