JPH0326129B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printing device with a petal-shaped type wheel. In this type of printing device, a large number of type wheels are prepared depending on the typeface and the pitch of the printed characters, and it is customary for the user to manually attach and detach the type wheel to be used each time. However, conventional printing devices have the disadvantage that skill is required to accurately set the position of the type wheel, and that it takes time and effort to attach and detach. In view of this point, it is an object of the present invention to provide a printing device in which the type wheel can be reliably and easily attached and detached with one touch.

Embodiments of the present invention will be described with reference to the drawings. 1st
In the figure, 1 is a platen, 2 is a petal-shaped type wheel, and 3 is a wheel cassette that accommodates the type wheel. The type wheel 2 is as shown in FIG.
Elastic spokes 5 having typefaces 6 at their tips are radially attached to the outer periphery of the central disk 4. 7 is a type selection motor, and a disk-shaped holder 8 is fixed to its rotating shaft 33. 9 is an engagement boss provided at the center of the holder 8, and 10 is an engagement boss 3 provided around it.
It is a convex part. These three protrusions 10 have the same height, but their positions are distributed at non-equiangular and non-equicircular positions as shown in FIG.

The disc 4 of the type wheel 2 has a recessed hole 11 (FIG. 1) in its center into which the engagement boss 9 fits, and around the recessed hole 11 there are positioning holes at positions corresponding to the protrusions 10. 12 are provided. 13 is a holding boss formed on the opposite side of the recessed hole 11. A wheel cassette 3 for storing the type wheel 2 is removably housed in a box frame 14a in front of the carriage frame 14, and a spring plate 15 attached to the box frame 14a.
The pushing piece 16 at the tip elastically presses the holding boss 13 of the type wheel 2 to urge the type wheel 2 toward the holder 8. The inner surface of the wheel cassette 3 facing the holder 8 forms a friction surface 3a. 17 is a printing hammer, which is fixed to the stand 18 together with the type selection motor 7;
8 connects the carriage frame 14 via the ball 19.
It is movably installed. 20 and 21 are stoppers. Reference numeral 22 denotes an operating lever that rotates about a spindle 23 provided on the carriage frame 14 as a fulcrum. There is an operation lever 2 on the side of the type selection motor 7.
A pin 24 is provided which engages with an oblong hole 25 provided in 2. A spring receiver 27 is provided at the lower end of the operating lever 22.
A toggle spring 26 supported by is attached.

Next, the operation of attaching and detaching the wheel cassette 3 containing the type wheel 2 will be explained. FIG. 1 shows the wheel cassette 3 inserted into the box frame 14a of the carriage frame 14. The toggle spring 26 pushes the pedestal 18 holding the print selection motor 7, holder 8 and printing hammer 17 backward, and the pedestal 18 is stopped by the stopper 21. Now, as shown in FIG.
2 forward, the toggle spring 26 pushes the pedestal 18 forward beyond the dead center, and the pedestal 18 is stopped by the stopper 20. At this time, the engagement boss 9 of the holder 8 fits into the recessed hole 11 of the type wheel 2, the axes of the type wheel 2 and the type selection motor 7 are set, and the protrusion 10 of the holder 8 fits into the disc of the type wheel 2. It comes into contact with the surface of 4. Since the three protrusions 10 have the same height, the disk 4 is pressed in the axial direction, and the opposite side contacts the friction surface 3a on the inner surface of the wheel cassette 3. At this time, when the type selection motor 7 is rotated in an arbitrary manner, the type wheel 2 is moved to the wheel cassette 3 by the friction surface 3a.
The protrusion 10 of the holder 8 rotates and slides on the surface of the disk 4 of the locked type wheel. When the three protrusions 10 are aligned with the positioning holes 12, the elastic force of the spring plate 15 causes the protrusions 10 to fit into the holes 12, and the holder 8 and the type wheel 2 are connected to each other. finish. At this time, the type wheel 2 moves to the side of the holder 8 by the height of the protrusion 10, so the type wheel 2 moves away from the friction surface 3a of the wheel cassette and rotates freely, and the back surface of the disc 4 of the type wheel 2 The plane and the front plane of the holder 8 come into pressure contact, and friction is generated between them against rotation. Fifth
The figure shows the state at this time.

As mentioned above, the three protrusions 10 of the holder 8 have the same height, and the holding boss 13 of the disc 4 is held down by the spring plate 15, so when the type wheel 2 comes into contact with the holder 8, (Figure 4) It maintains an accurate posture relative to the axis without tilting or wobbling. Further, since the protrusion 10 and the through hole 12 engage only at one point on the circumference, no deviation in the relative angle between the type wheel 2 and the holder 8 occurs. In this way, by inserting the wheel cassette 3 into the box frame 14a of the carriage frame and tilting the operating lever 22 forward, the wheel cassette 3 can be attached to the carriage frame 14 very easily and accurately. Can be done. The operation when removing the type wheel 2 is similarly easy. That is, when the operating lever 22 is tilted backward, the pedestal 18 moves back and the holder 8 moves to the type wheel 2.
The type wheel 2 can be easily pulled out together with the wheel cassette 3 since it is in the state shown in FIG. The type wheel 2 is held down by the spring plate 15, but there is a limit to the pressing stroke of the spring plate 15, and the pushing piece 16 at the tip and the holding boss 13 have spherical surfaces on their surfaces for smooth contact. Since it has been processed, there is no problem in taking out the type wheel 2.

FIG. 7 shows a conventional type wheel holding structure. This structure is based on the rotating shaft 3 of the type selection motor.
A positioning member 29 is attached to the holder 28 fixed to the
The holding elastic member 30 and the stopper 31 are provided separately, and the type wheel 32 is also provided with a corresponding member. This structure not only complicates the structure of the holder 28, but also fixes the type wheel 32 using the holding elastic member 30, so if the accuracy of the member 30 decreases, the type wheel will run out, causing the printing device to This can cause a fatal defect.

On the other hand, in the present invention, the holder 8
The positioning hole 12 of the circular plate of the type wheel 2 fits into the protrusion 10 provided on the front surface of the holder 8, and the spring plate 15 presses the type wheel 2 against the flat surface of the front surface of the holder 8. Not only is this simple, but since a frictional force is generated between the back surface of the disk 4 of the type wheel and the front plane of the holder 8, bending stress is not substantially applied to the protrusion 10, so that the protrusion 10 becomes fatigued. It is highly durable without any damage.

[Brief explanation of the drawing]

FIG. 1 is a side view of an embodiment of the printing device of the present invention;
FIG. 2 is a perspective view of the type wheel and type selection motor of the present invention, FIG. 3 is a front view of the holder of the present invention, and FIG. 4 is the printing device of the present invention when inserting and aligning the type wheel. side view, fifth
The figure is a side view of the printing device of the present invention when the alignment of the type wheel is completed, Figure 6 is a view of Figure 1 seen from the rear, and Figure 7 is a diagram showing the conventional type wheel and its fixing structure. be. 1...Platen, 2...Type wheel, 3...
...Wheel cassette, 3a...Friction surface, 4...Disk, 5...Elastic spoke, 6...Print, 7...Print selection motor, 8...Holder, 9...Engagement boss, 10...Convex 11... Recessed hole, 12... Through hole, 13... Holding boss, 14... Carriage frame, 14a... Box formwork, 15... Spring plate, 16
... Push piece, 17 ... Printing hammer, 18 ... Stand, 19 ... Ball, 20, 21 ... Stopper,
22... Operating lever, 23... Spindle, 24
... Pin, 25 ... Oval hole, 26 ... Toggle spring, 27 ... Spring receiver, 33 ... Rotating shaft.

Claims (1)

[Scope of Claims] 1. A printing device that performs printing by attaching a petal-shaped type wheel radially provided around a disk having a locking hole, which comprises a circular type wheel attached to a rotating shaft of a type selection motor. a plate-shaped holder; a protrusion provided on a surface facing the disc of a type wheel mounted on the holder at a position corresponding to a locking hole provided in the disc of the type wheel; a biasing means for biasing the type wheel so as to press the disc of the type wheel against the holder; and a biasing means for biasing the type wheel so as to press the disc of the type wheel against the holder; A printing device comprising: means for holding the type selection motor at a position where a surface facing the mounted type wheel and a surface of a disc of the type wheel facing the holder are in pressure contact.