JPS6132988B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printing device that uses a type wheel.

Using a so-called petal-shaped wheel with type attached to the tips of many spokes arranged radially around the boss, a selection motor successively selects the desired type and brings it to the printing position, and the type is printed from the back side. 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.

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

DESCRIPTION OF THE PREFERRED EMBODIMENTS Details of embodiments of the present invention will be described 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. A boss portion 6 is provided on the center plate 5.

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 is inserted into the boss portion 6 . The shaft 9 is formed with a tapered part 10 at its tip so that the shaft 9 can be smoothly inserted into the boss part 6 even if the vertical position of the type wheel 2 is slightly shifted.

A gripping member 11 is fixed to the shaft 9, and the gripping member 11 is a retainer that connects the first positioning means configured as a positioning arm 12 and the wheel 2 as shown in FIG. Elastic piece 13
and a stopper 14 that maintains the perpendicularity of the wheel 2 to the motor shaft 9 and the coupling depth. In this case, the positioning arm 12 is connected to the motor 8
The elastic piece 13 and stopper 14 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 retaining holes 16 are formed in which the shaft 9 is fixed when the shaft 9 is fully inserted into the boss of the type wheel 2. The positioning arm 12 of the gripping member 11 is inserted into the holding hole 16, and the elastic piece 13 of the gripping member 11 is inserted into the holding hole 16. 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 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. 21. Switching lever 20
is rotatably attached to a first pin 22 fixed to the carriage 18, and a second pin fixed to the casing 17 is attached to a long hole 20a formed in the lever 20.
The pin 23 is fitted. 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 mounting a petal-shaped wheel in a printing device constructed as described above will be explained based on the petal-shaped wheel mounting 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, are moved to the center plate of the wheel. (See Figure 5). In this FIG. 5, the second pin 23 is connected to the elongated hole 2 of the switching lever 20.
0a, 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 shifted in the direction of arrow C, and the cassette 1
It comes into contact with the protrusion 7 of. 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. Then, when the shaft 9 is rotated by at least 120 degrees, the positioning arm 12 and the elastic piece 13 are aligned 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 installation, the home position of the type wheel is detected and printing is performed.

As described above, the printing device according to this embodiment can be attached by operating the switching lever and rotating the motor.

FIG. 6 shows another embodiment of the present invention. In this embodiment, an engaging hole 15' into which a positioning arm of a gripping member is inserted into the center plate 5 of the type wheel 2.
and three holding holes 16' into which elastic pieces are inserted are formed, but the positions of these holes 15', 16' are shifted in the radial direction of the wheel. If the tips of the arm and the elastic piece are provided on the circumference so as to fit into these holes, the wheel and motor can be connected in only one way.

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 printing device according to the present invention has been explained using an embodiment using a cassette type wheel, it is applicable not only to a cassette type wheel but also to a printing device using a normal type wheel. This will be explained using the example shown in the figure.

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 this example, the receiving portion 25a is provided with a semi-annular projection 26 on the lower side to increase the area of contact with the boss 6 and to stably hold the type wheel 2. A notched or rubber blocking 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, but may include friction means that can hold the type wheel and prevent the type wheel from being rotated by this rotation even if the gripping member is pressed and rotated. Of course, it can be of any shape as long as it can be installed.

Therefore, according to the present invention, when replacing the type wheel, the operator can replace the type wheel without considering the position of the type wheel and the motor, and the operability when replacing the type wheel is dramatically improved. An improved printing device can be provided.

[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 same as in 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
... shaft, 12 ... positioning arm, 13 ... elastic piece,
15, 15'...Engagement hole, 16, 16'...Retaining hole, 1
8...Carriage body, 21...Click spring.

Claims (1)

[Scope of Claims] 1. A printing device using a type wheel having a plurality of characters, comprising: a type wheel drive motor having a shaft for rotating the type wheel; and a type wheel drive motor provided on the shaft of the type wheel drive motor. a second positioning means provided on the type wheel for engaging the first positioning means and transmitting rotation of the shaft of the type wheel drive motor to the type wheel; between a first position for engaging the first positioning means and the second positioning means and a second position for exchanging the type wheel that is farther from the type wheel than the first position; a carriage on which the type wheel drive motor is movably mounted; an operating section for moving the type wheel drive motor to the first position; and a carriage for supporting the type wheel or a cassette containing the type wheel. a support means;
the type wheel drive motor when the type wheel drive motor is in the first position and rotates the shaft of the type wheel drive motor to engage the first positioning means and the second positioning means; In order to prevent the rotation of the type wheel, a rotation prevention means is provided on the side of the type wheel opposite to the side where the type wheel drive motor is located and engages with a part of the type wheel to prevent rotation of the type wheel. A printing device characterized in that the first positioning means and the second positioning means are engaged by cooperation of the rotation prevention means and the rotation of the shaft of the type wheel drive motor.