JPS5913985B2 - Printer wheel reset mechanism - Google Patents

Description

[Detailed Description of the Invention] 10 In the present invention, when resetting, the type wheel rotates in the normal direction and returns to the starting position, so no shock is generated, and by using a special solenoid. A reset mechanism for a printer that can save power by reducing printing and driving force, and has a much simpler structure than that of Touhei's 15 will be described in detail below with reference to embodiment drawings.

In the figure, reference numeral 1 denotes a character wheel having type 2 on its outer periphery, leaving a non-print portion 1a, and is loosely fitted onto a 20-character wheel axle 5 which is driven as appropriate.

However, each character ring has a ratchet 3 on one side,
An arcuate leaf spring 254 is housed in the recess 18 formed on the side surface of each ratchet, and one end of which comes into elastic contact with the wheel shaft 5, and a suitable position on the side surface that elastically contacts the inner bottom of the recess 18. 1, when it is not restrained by the latch plate described later, it is rotated together with the wheel axle 5, but when it is restrained, it does not rotate and only the wheel axle 5 idles. .

30 Each ratchet 3 has teeth 3a corresponding to the letters of the respective character wheels, and also includes reset teeth 3b whose protrusion is slightly larger than these teeth 3a.

Reference numeral 6 denotes a latch plate 35 that engages and disengages the ratchet of each character ring, and has flanges 10b and 1 at both ends of the horizontally long back plate portion 10a.
the flange 10b of the latch holder 10 having 0b;
The latch shaft 9 is loosely fitted into the latch shaft 9 disposed horizontally between the latch shafts 10b, and both ends of the latch shaft 9 are supported by appropriate immovable parts.

The latch holder 10 is given a rotational force in the circumferential direction (counterclockwise in FIG. 2) by a suitable spring 12, and the lower part 1S10c is locked to the stopper part 8.

7 is a cam that rotates the latch plate by a certain angle;
There is a large diameter part 71 following the small diameter part 7s, and a starting protrusion 7h further protrudes at the end of this large diameter part. direction), and rotates once for every two rotations of the character wheel 1.

Further, the latch plate 6 has a locking pawl 6c to be engaged with the latch, and a laterally protruding interfered portion 6a.
15 is an iron core around which a coil 17 is wound, and the rear end of a magnet 11fζ provided on the yoke 14 is connected so that the underline 6d of the interfered part 6a comes into contact with the cam. Moreover, the tip of the iron core 15 is connected to the yoke 1.
When the coil 17 is energized, the magnet that attracts the actuating piece 16 is demagnetized.

The lower end 6b of the latch plate 6 thus engages the actuating plate 16. The locking pawl 6c of the latch plate 6 engages with the teeth of the latch 3 when the small diameter portion 7s of the cam 7 comes to the interfered portion 6a, and the latch 3 engages with the teeth of the latch 3 at the large diameter portion 71.
Although it is outside the rotation locus of the tooth, it is within the rotation locus of the reset tooth 3b and can engage with the set tooth 3b, and the protrusion 7h of the cam prevents the rotation of the reset tooth 3b. It is designed to be positioned outside the trajectory. Further, the latch plate 6 has a notch 21 formed therein, which is fitted into the back plate 10a of the latch holder 10, and the latch plate 6 has a compression spring 31 provided in the back plate spring receiver 32 of the latch holder 10. A rotational force in the counterclockwise direction in FIG. 2 is applied by.

In the figure, 13 represents a platen, 19 represents a ribbon, and 20 represents paper.

The apparatus of the present invention has the above-described structure, and is in the state shown by the solid line in FIG. 2 before entering character selection.

In the character selection process, when the protrusion 7h of the rotating cam 7 passes through the interfered part 6d of the latch plate 6, the latch plate 6 is forcibly rotated clockwise around the latch shaft 9, and the latch plate is engaged. The retaining pawl 6c is removed from the ratchet glue set tooth portion 3b.

When the projection 7h finishes passing through the interfered portion 6d, the latch plate is rotated back by the spring 316ζ. The character wheel 1, whose locking pawl 6c of the latch plate has come off the latch, is rotated counterclockwise in Figure 2 along with the character wheel shaft by the frictional force of the spring 4, and just before the selected character arrives at the printing area
A pulse current is applied to the coil 17 of the iron core.

As a result, the iron core 15 releases the adsorbed movable piece 16, and the movable piece 16 releases the rotation blocking force of the latch plate 6 by the spring 31, so that the latch plate 6 is rotated by the spring 31. , the locking pawl 6c of the ratchet 3 engages with the teeth of the ratchet 3, and the character ring 1 stops with the type selected (FIG. 5). Even when the coil 17 is no longer energized, the latch plate 6 is held by the spring 31 in such a state that the locking pawl 6c continues to engage with the teeth of the ratchet, and while the latch plate 6 is held, the plantain 13 is Move in the direction of the arrow in the figure and press the paper 20 according to the selected type.
After printing, the platen moves back.

Next, when the large diameter portion 71 of the cam 7 reaches the interfered portion 6a of the latch plate 6, the latch plate 6 is rotated clockwise and removed from the teeth of the latch (
position shown in solid line).

As a result, the character wheel 1 rotates again together with the character wheel shaft 5, and stops when the reset tooth 3b engages with the locking pawl 6c of the latch plate. That is, the character wheel is reset to its original starting position. However, at this time, the lower end 6b of the latch plate being rotated comes off from the movable piece 16, so that the movable piece 16 is again attracted to the iron core 15, and the latch plate is held at the starting position.

Thereafter, the selection and reset of printed characters are performed in the same manner.

As described above, according to the present invention, the character wheel 1 can be rotated forward in the same direction as when selecting a type even if it is S at the time of resetting. There is no impact when setting.

Moreover, since the coil 17 of the adsorption core 15 can be energized to release the adsorption force of the core only when printing, the drive power is small, saving power and having the advantage of simplifying the structure. There is.

[Brief explanation of drawings]

The figures show an example of the mechanism according to the present invention, in which Fig. 1 is a plan view thereof, Fig. 2 is a vertical cross-sectional front view, Fig. 3 is a perspective view of the latch holder, and Figs. 4 and 5 are operational views. It is a figure showing a state. In the diagram, 1... letter ring, 2... typeface, 3...
...Rachet, 3a...Teeth, 3b...
...Reset tooth, 4... Spring, 5...
...Character wheel axle, 6...Latch plate, 6a...
...Interfered part, 6c...Latching claw, 6d...
...Underline of the interfered part, 7...Cam, 7s.
...Small diameter part, 71...Large diameter part, 7h...
...Protrusion, 8...Stopper, 9...
...Latch shaft, 10...Latch holder, 11.
...Magnet, 12...Spring, 13...
...Platen, 14...Solenoid support, 1
5... Iron core, 16... Movable piece, 17.
...Coil, 18...Dent, 19...
...Ribbon, 20...Paper, 21...
Notch, 31... Spring.

Claims (1)

[Claims] 1. A ratchet having one reset tooth on the outer periphery and teeth corresponding to the type is provided on the side, a character wheel is frictionally engaged with the ratchet and rotated by the character wheel shaft, and the ratchet is attached to a shaft parallel to the character wheel shaft. , a rotational return force is applied by the spring in the same direction as the wheel axle, and the engaging part is locked to the stopper part,
In addition, the latch holder houses a compression spring in a spring receiver provided on the back plate, and is attached to the shaft of the latch holder.
It has a locking pawl to engage with the ratchet, and
A latch plate that is rotated in the same direction as the wheel axis by the spring force of the latch holder so that the locking pawl is positioned within the rotation locus of the teeth of the ratchet, around an axis parallel to the wheel axis and in the opposite direction to the wheel axis. The latch plate has a large diameter portion that is rotated by the small diameter portion, and a large diameter portion that continues to the small diameter portion, and a protrusion portion that has a larger diameter at the terminal end of the large diameter portion, and the locking pawl of the latch plate is connected to the teeth of the ratchet at the small diameter portion. a cam that engages and deflects the locking pawl at the large diameter portion outside the rotational trajectory of the ratchet teeth but within the rotational trajectory of the reset teeth, and at the protrusion portion to deflect the locking pawls out of the rotational trajectory of the reset teeth. The solenoid is constructed by winding a coil around an iron core having a magnet at one end, and a movable piece that blocks the rotational return force of the latch plate spring is connected to the magnet connected to the end of the iron core. A printer wheel reset mechanism in which a movable piece of the iron core is attracted by force and the adhesion force of the movable part of the iron core is released by energizing the coil.