JPS6042037B2 - Character selection mechanism for small printers - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a small printer, and more particularly to a motion conversion mechanism for selecting characters.

Conventionally, a typical character selection mechanism of a printer using a type wheel has a structure as shown in FIG. To explain this simply, the type wheel 1, which is frictionally coupled or spring-coupled to the drive shaft 4 by a spring or the like, rotates in the direction of arrow A as the drive shaft 4 rotates. When the desired type 2 on the type wheel 1 appears at the printing position, the selection pawl 5 is actuated, and the type wheel 1 is locked.
That is, when the desired type 2 appears at the printing position, when the electromagnet 8 is energized in synchronization with this, the suction plate 11 is actuated, and the actuating plate 12, which had been locking the selection claw 5, is also moved in the direction of arrow B. Operate. Therefore, the selection pawl 5 rotates around the shaft 6 in the direction of arrow C by the action of the leaf spring 7, and selects the type 2 on the type wheel 1.
The type wheel 1 is engaged with the corresponding ratchet 3 to lock the type wheel 1. The locked type wheel 1 remains stationary, and only the drive shaft 4 continues to rotate. When character selection for each digit is completed in this way, the platen 14 around which the printing paper 16 is wrapped
By pressing the ink ribbon 15 against the type 2, desired characters can be printed on the printing paper 16. After printing, the selection pawl 5 is reset by rotating the reset cam 17 in the direction of arrow D. The above is the general operation of the conventional character selection mechanism.

As will be seen, in order to operate the selection claw 5, the electromagnet 8 must be composed of an iron core 9, a yoke 10, a suction plate 11, an actuating plate 12, a return spring 13 for the actuating plate 12, etc., and the structure is complicated. I had no choice but to do so. In addition, in terms of power consumption, the iron core 9 and the suction plate 11 face each other with a gap in between, and operate only by mutual attraction, so a relatively large current is required. In addition, the suction force generated on the suction plate 11 is generated by the leaf spring 7,
It was necessary to overcome the frictional load between the selection claw 5 and the actuating plate 12 and the spring load of the compression spring 13. This was also a major factor in increasing power consumption. An object of the present invention is to obtain a character selection mechanism that consumes less power, is easy to assemble, and operates reliably by arranging an iron core to stand by at a position that is offset in advance from the stable attraction point of the permanent magnet. There is a particular thing.

The present invention will be explained below using the embodiments shown in FIG. 2 and thereafter. First, an embodiment of the present invention will be described with reference to FIG.
It should be noted that parts given common numbers in each figure are parts that perform the same function, so repeated explanations will be omitted. Second
In the figure, reference numeral 33 denotes a movable member consisting of an iron core 21 and a claw portion 22, which is rotatably inserted into the shaft 20. Reference numeral 23 denotes a selection claw, one end of which engages with the claw portion 22 of the movable member 33, and the other end of which engages with the ratchet 3 of the type ring 1 during selection.

Further, the selection claws 23 are arranged in several numbers along the direction of the numbers by guide members 30, and obtain torque in the direction of arrow C by the action of the first permanent magnets 31. 25 is a second permanent magnet facing the iron core 21, and 26 is a yoke for closing the magnetic path.

28, a part of the iron core 21 is arranged in the air core part, and the shaft 20 is selectively attached.
This is an electromagnetic coil in which the hollow core part can rotate around the outer core.

The end of the iron core 21 is attached to this electromagnetic coil 28 as a second permanent magnet 2.
When the movable member 33 is excited to have the same polarity as 5, the movable member 33 obtains a repulsive force and rotates in the direction of arrow A. Due to this movement, the engagement between the claw portion 22 and the selection claw 23 is disengaged, and the selection claw 33 is rotated in the direction of arrow C by the action of the first permanent magnet 31 to engage with the ratchet 3 and engage the type wheel 1. Stop. Immediately after locking, excitation of the electromagnetic coil 28 is stopped. When the selection is completed by performing the same operation for each digit, the platen 14 is actuated to print on the printing paper 16.
0 around the selection claw shaft 24 in the direction of arrow D, the elastic member 32 presses the selection claw 23. When the selection claw 23 returns to its original position, the movable member 33
is rotated in the direction of arrow B until the iron core 21 comes into contact with the stopper 27 due to the attraction action of the second permanent magnet 25, and then stops and waits. The stopper 27 connects the iron core 21 to the second permanent magnet 25.
This is so that the iron core 21 can easily pop out when the electromagnetic coil 28 is energized. According to this embodiment, by using the second permanent magnet 25, the electromagnetic coil 2
8 can be made extremely small and the operation is reliable. Further, in this embodiment, the spring 13 for returning the operation shown in FIG. 1 is replaced by the attractive force of the second permanent magnet 25, so that the number of parts can be reduced and there is no energy loss during operation. In this embodiment, if the operation of the movable member 33 is the first step, the operation of the selection claw 23 is the second step, and the type wheel 1 is selectively locked through two operations, which is disadvantageous in terms of time. They tend to be large and require a large number of component parts.

The embodiment shown in FIG. 3 is a further improvement in this respect. In FIG. 3, a movable member 40 includes an iron core 41, a selection claw 42, and a protrusion 43.

The iron core 41 is placed on standby by being offset from the stable magnetic attraction point of the second permanent magnet by a stopper 48. 47 is York,
49 is an electromagnetic coil that includes the iron core 41.

When the electromagnetic coil 49 is energized, the iron core 41 is magnetized to the north pole as shown in the figure, which repels the north pole of the second permanent magnet 46 and rotates in the direction of arrow E. This rotation causes the selection pawl 42 to rotate in the direction of arrow H, thereby selectively locking the type wheel 1. The protruding part 43 similarly rotates and reaches the position 43'' shown by the dotted line.This means that the protruding part 43 receives the magnetic attraction force from the first permanent magnet 51, and the electromagnetic coil 49 is de-energized. This also means that the selection claw 42 maintains the selected state.
After printing is completed, the movable member 40 is reset by rotating the resetper 50 around the selection claw shaft 45 in the direction of arrow G. In the reset standby state, the standby state is maintained unless the attraction force of the second permanent magnet 46 that the iron core 41 receives is greater than the attraction force of the first permanent magnet 51 that the protrusion 43 receives. In this embodiment, since the iron core 41 and the selection pawl 42 are integrated, the mechanism is simplified and the operating time is shortened, thereby making it possible to increase the speed of the printer. As described above using several embodiments, the character selection mechanism according to the present invention is superior to the conventional one in the following points.
1. By using permanent magnets, there is no need for spring members and their mounting parts, as well as assembly and adjustment man-hours.

It is very advantageous in terms of cost. By using two permanent magnets, the synergistic effect with the electromagnetic coil, that is, the repulsive force and attractive force can be effectively used, so power consumption can be significantly reduced.

3.Unnecessary friction parts have been removed by reducing the number of spring members, etc.
This provides a character selection mechanism that is extremely reliable in terms of operation and durability.

As explained above, according to the present invention, since the iron core is placed on standby by being offset from the stable attraction point of the permanent magnet, the iron core can easily pop out when the electromagnetic coil is excited, and it can be consumed. The effect is that the iron core can be operated easily and reliably without increasing the power.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing a conventional character selection mechanism, in which 1 is a type wheel, 5 is a selection claw, 7 is a leaf spring, 8 is an electromagnet, and 14 is a platen. FIG. 2 is a side sectional view showing an embodiment of the present invention, in which 33 is a movable member, 21 is an iron core, 25 is a second permanent magnet, 28 is an electromagnetic coil, 23 is a selection claw, and 30 is a guide member. . FIG. 3 is a side sectional view showing another embodiment of the present invention, in which 40 is a movable member, 41 is an iron core, 42 is a selection claw, 43 is a protrusion,
46 is a second permanent magnet, 47 is a yoke, 48 is a stopper,
49 is an electromagnetic coil, 50 is a resetper, and 51 is a first permanent magnet.

Claims (1)

[Scope of Claims] 1. A movable type ring having a plurality of movable characters disposed on its outer periphery and ratchet teeth provided corresponding to the movable characters on the side surface, and which selectively rotates and stops repeatedly; and a selection of the ratchet teeth. a first permanent magnet that maintains the selection pawl in engagement with the ratchet teeth; and an iron core portion and a pawl portion, the pawl portion being a movable member that is controlled to engage or disengage the selection pawl with the ratchet teeth; and an electromagnetic coil having the iron core portion passed through the air core portion. , a second electrode disposed opposite to one end of the iron core portion, which acts to disengage the claw portion and the selection claw by operating the movable member by excitation of the electromagnetic coil;
a permanent magnet; a stopper member for causing the movable iron core to stand by at a position offset from a stable attraction point of the second permanent magnet; and a stopper member for causing the selection claw engaged with the ratchet tooth to return to the standby position a reset member for re-engaging;
A character selection mechanism for a small printer consisting of: 2. A type wheel that selectively rotates and stops, having a plurality of type characters arranged on its outer periphery and ratchet teeth provided corresponding to the type characters on the side surface, and an iron core portion, a selection claw portion, and a protrusion integrally formed with the type ring. a movable member having a hollow core portion, an electromagnetic coil having an air core portion passing through the iron core portion, and a first permanent magnet that urges the movable member in a state in which the selection claw portion engages with the ratchet teeth; a second permanent magnet that is disposed opposite to one end of the iron core portion and acts to cause the selection pawl portion to engage with the ratchet teeth by operating the movable member by excitation of the electromagnetic coil; and the movable member. a reset member for returning the selection pawl part engaged with the ratchet teeth to a standby position by a returning operation; and a reset member for biasing the iron core part from a stable attraction point of the second permanent magnet to move the movable member A character selection mechanism for a small printer consisting of a stopper member for positioning the printer in a standby position.