JPS64222B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a printing device.

Using a so-called petal-shaped wheel with type attached to the tips of many spokes arranged radially around the boss, the desired type is sequentially selected by a selection motor and brought to the printing device, and the type is printed from the back of the type. Printing devices that print using a printing hammer are already known. In this type of printing device, a type wheel is attached to the type selection motor shaft, and many types of type wheels are prepared to be applied to many types of fonts. However, in such conventional printing devices, it is not easy to replace the type wheel, and the operator's hands become dirty when replacing the type wheel.

In order to solve this problem, the applicant has proposed a wheel cassette in which a type wheel is housed within the cassette. This wheel cassette attachment mechanism has a holding means for keeping the type wheel in a constant position with respect to the cassette, and a holding means using, for example, a sensor for keeping the gripping member on the motor side at a constant position. and
By these means, the type wheel and the gripping member are in a fixed position, that is, the home position, so that the type wheel can be easily mounted. However, since there is a possibility that the wheel cassette can be touched by the operator's hand, there is a risk that the home position of the type wheel will be deviated. or,
There was a problem in that the gripping member on the motor side was also maintained at the home position when the power was turned on, but there was no guarantee that it would be maintained at the home position when the power was turned off.

Additionally, in order to facilitate the attachment of the motor and type wheel, the wheel side is provided with fine irregularities, and the motor side's grip is provided with a pin, and this pin is configured to fit into the recessed part of the above-mentioned irregularities. A mounting mechanism for a type wheel has been proposed. However, with this type of mechanism, there was a problem in that when the pin came directly above the convex part of the unevenness, the pin did not slip and remained as it was, that is, the type wheel was not attached.

SUMMARY OF THE INVENTION An object of the present invention is to provide a printing device that reliably eliminates the above-mentioned problems and has significantly improved operability.

The details of the present invention will be explained below with reference to the accompanying drawings.

In FIG. 1, a petal-shaped wheel 2 is housed in a box-shaped cassette 1. As shown in FIG. 2, the petal-shaped wheel 2 has a center plate 5 on which a number of spokes 4 having typefaces 3 are arranged radially. The center plate 5 has a boss portion 6 in which a center hole is formed.
is provided.

A support hole 1a is formed in the cassette 1, into which a boss portion 6 of a type wheel 2 is loosely fitted. A projection 7 is formed on the type wheel side of this support hole 1a.

A shaft 9 of a type selection motor 8 serving as type wheel driving means is inserted into the boss portion 6 . Axis 9
is formed with a tapered part 10 at the tip, so that even if the vertical position of the type wheel 2 is slightly shifted, the shaft 9
can be inserted into the boss portion 6 smoothly.

A gripping member 11 as a transmission means is fixed to the shaft 9, and this gripping member 11 is a pull-out member that connects a positioning means constituted as a positioning arm 12 and a wheel 2 as shown in FIG. It has a stopper elastic piece 13 and a stopper 14 that maintains the perpendicularity of the wheel 2 to the motor shaft 9 and the connection position. In this case, the positioning arm 12 also serves to transmit the rotation of the motor 8, and the elastic piece 1
3 and the stopper 14 can also serve to maintain the attitude of the wheel.

Three engagement holes 1 in the center plate 5 of the type wheel 2
5 and three holding holes 16 are formed, and when the shaft 9 is fully inserted into the boss of the type wheel 2, the gripping member 1 fixed to the shaft 9 is formed in the engaging hole 15.
1 positioning arm 12 is inserted, and the holding hole 1
6, the elastic piece 13 of the gripping member 11 is inserted.
In the case of this example, the elastic pieces 13 are opened at the same angle (120°) and their tips are on the same circumference, so that the gripping member 11 and the type wheel 2 can be connected in three ways.

In FIGS. 3 and 4, the type selection motor 8
is fixedly inserted into a casing 17, and the casing 17 is slidably attached to the carriage body 18 in the directions of arrows C and D. A switching device 19 is interposed between the side plate of the casing 17 and the side plate of the carriage body 18 as an elastic pressing means for pressing the gripping member against the center plate, and this switching device 19 includes a switching lever 20 and a click spring 21. are doing. The switching lever 20 is rotatably attached to a first pin 22 fixed to the carriage 18, and a second pin 23 fixed to the casing 17 is fitted into a long hole 20a formed in the lever 20. . Further, one end of the click spring 21 is attached to this second pin 23, and the other end is attached to a third pin 24 fixed above the first pin 22 of the carriage 18.

Next, a method for attaching a petal type wheel to a printing device configured as described above will be explained based on the petal type wheel attachment device.

FIG. 3 shows a state in which the switching lever 20 is rotated in the direction of arrow B and the character selection motor 8 is separated from the cassette 1. In this state, the motor 8 is stationary.

That is, the action of the click spring 21 urges the casing 17 in the direction of arrow D, but the action of the click spring 21 urges the second pin 2
3 is in contact with the upper end of the elongated hole 20a, so that it remains stationary. In this state, the cassette 1 is replaced or the like. The replaced cassette 1 is held upright by a support member (not shown) or the like.

When the switching lever 20 is rotated in the direction of arrow A, the casing 17 moves in the direction of arrow C.
At this time, since the second pin 23 moves to the left in the figure from the third pin 24, the direction of action of the click spring 21 changes, and the tips of the gripping member 11, that is, the tips of the positioning arm 12 and the elastic piece 13, touch the center plate of the wheel. 5 (see Figure 5). In FIG. 5, since the second pin 23 is located at the center of the switching lever 20 near the elongated hole 20a, the elastic action of the click spring 21 acts in the direction of pressing the gripping member 11 against the center plate. Due to this action, the type wheel 2 is displaced in the direction of arrow C and comes into contact with the protrusion 7 of the cassette 1. Also, at this time, the tapered portion 10 of the shaft 9 fits into the boss 6.

A friction member such as unevenness or rubber is attached to the contact portion between the protrusion 7 and the type wheel 2 as a rotation prevention means for increasing the frictional force on at least one side and preventing rotation of the type wheel.
Further, it is convenient that the ends of the positioning arm 12 and the elastic piece 13 of the gripping member 11 are formed to have a rounded shape so as to reduce the frictional force.

In this state, when the type selection motor 8 is energized to rotate the shaft 9, the type wheel 2 does not rotate due to the friction means, but the gripping member 11
It rotates as if sliding. and at least axis 9
When rotated by 120 degrees, the positioning arm 12 and the elastic piece 13 align with the engagement hole 15 and the holding hole 16, respectively, and are fitted together (see FIG. 1).

In this type wheel 2, since the elastic piece 13 is fitted into the holding hole 16, the front surface of the type wheel 2 is separated from the protrusion 7 by the protrusion 13a of the elastic piece 13, and the rotation prevention effect of the wheel is released. Ru. After this adhesion, the home position of the type wheel is detected and printing is performed.

As described above, the type wheel mounting method according to the present invention allows mounting by simply operating the switching lever and rotating the motor.

In FIG. 6, the center plate 5 of the type wheel 2
An engagement hole 15' into which the positioning arm of the gripping member is inserted, and three holding holes 16' which are first engagement parts into which the elastic pieces are inserted are formed.
The positions of these holes 15', 16' are offset in the radial direction from the center hole of the wheel. The arm 12 and the elastic piece 13 which is the second engaging part
If the tips of the wheels are provided on the circumference so as to fit into these holes 15' and 16', there is only one way to connect the wheel and the motor.

This configuration has the advantage that the coupling relationship between the wheel and the motor is always constant, so that detection of the home position is not necessary.

Although the embodiment has been described with respect to a cassette type wheel, the present invention is applicable not only to a cassette type wheel but also to a method of mounting a normal type wheel, an example of which is shown in FIG.

In FIG. 7, 25 is a support member that supports the type wheel 2, and this support member 25 is fixed to a carriage (not shown). The support member 25 is a central member formed into two parts, and the boss 6 of the type wheel 2 is loosely fitted into the two-pronged receiving part 25a, so that the type wheel 2 is held in an upright state. In addition, in this example, the contact area with the boss 6 is increased below the receiving part 25a, and the type wheel 2
A semi-annular protrusion 26 is provided to stably hold the holder. A notched or rubber friction member 27 is provided on the surface of the protrusion 26 facing the type wheel 2 to prevent the type wheel from rotating when the gripping member 11 presses the type wheel 2 and rotates.

According to the above configuration, even a type wheel that does not use a cassette can be reliably automatically mounted.

In this case, the support member is not limited to the one shown in the above embodiment, and can hold the type wheel in an upright state, and even when the gripping member is pressed and rotated.
Of course, any shape may be used as long as it is possible to install friction means that can prevent the type wheel from rotating due to this rotation.

According to the present invention, the operator can mount the wheel without considering the relationship between the type wheel and the position of the shaft of the type wheel drive means, and the replaceability of the type wheel is dramatically improved.

[Brief explanation of the drawing]

The drawings show a printing device according to the present invention, in which Fig. 1 is a sectional view showing the type wheel installed, Fig. 2 is a perspective view showing the type wheel and the gripping member, and Fig. 3 is a sectional view showing the type wheel and the gripping member. A partial cross-sectional view showing the state in which the motor is separated, Figure 4 is the - of Figure 3.
5 is a partial sectional view showing when the gripping member is pressed; FIG. 6 is a rear view of a type wheel showing another embodiment of the present invention; and FIG. 7 is a perspective view showing still another embodiment. It is. 2... Type wheel, 8... Type selection motor, 9... Axis, 12... Positioning arm, 13
...Elastic piece, 15,15'...Engagement hole, 16,1
6'...Retaining hole, 18...Carriage body, 21
...Click spring.

Claims (1)

[Scope of Claims] 1. A printing device using a type wheel having a plurality of type characters, comprising: a type wheel driving means having a shaft for driving the type wheel; and a type wheel driving means provided on the shaft of the type wheel driving means and configured to rotate the shaft. a central hole provided at the center of the type wheel for receiving the shaft of the type wheel drive means; a plurality of first engaging portions provided at positions; and a plurality of first engaging portions provided on the transmission means at different radial distances from the axis of the type wheel drive means for engaging with the first engaging portions. a second engaging part of the same number as the first engaging part; and a shaft of the type wheel driving means is engaged with the center hole of the type wheel in order to engage the first engaging part and the second engaging part. a rotation preventing means provided on the opposite side of the type wheel to the side where the type wheel driving means is located, in order to prevent the type wheel from rotating when the type wheel is rotated in a state in which the type wheel is rotated; A printing device characterized in that the first engaging part and the second engaging part engage in one way by cooperation of the means, and the type wheel and the transmission means are aligned.