JPS60120076A - Printing hammer - Google Patents

Abstract

PURPOSE:To prevent a plunger from rebounding, by a method wherein a rear end part of a plunger is brought into surface contact with a shock-absorbing member of a weight over the entire part of the contact surface at the time of a returning motion of the plunger, in a printer comprising a flower leaf form type wheel or the like. CONSTITUTION:In a printing hammer device 15, when the plunger 6 operated for typing is about to be returned beyond a stand-by position by a spring force, a rear end face 6A of the plunger 6 first comes into contact with the shock-absorbing member 23, and the recoil strength thereof starts to be absorbed. At this time, a surplus of the recoil strength tends to turn the weight 20 around a rotary shaft 11 against a weight-holding spring 13, but it is transmitted to the weight 20 through an arm part 22A of a holding member 22 provided with the shock- absorbing member 23, so that it is absorbed by the arm part 22A having a spring force, and the member 23 and the rear end face 6A of the plunger 6 are brought into surface contact with each other over the entire part of the contact surface. Accordingly, the plunger can be prevented from rebounding by the total effect of the elasticity of the shock-absorbing member 23, the spring force of the arm part 22A and the holding spring 13.

Description

TECHNICAL FIELD The present invention relates to printing hammers, and more particularly to printing hammers operated by plunger-type solenoids, such as those used in printers with petal-type type wheels.

[Prior art]

In conventional printers of this type, printing is performed by causing a printing hammer to strike the type provided on the type wheel together with an ink ribbon toward the printing paper on the platen. When one character is printed, it rotates at high speed to select the next character and place it in the printing position.

During this time, however, the plunger of the printing hammer returns to its original standby position, that is, to its rest position.

If the plunger rebounds and flies out to the side of the type wheel instead of staying in its original position, it may come into contact with it and cause erroneous printing, and there is a risk that the wheel may be damaged and printing may become impossible. be.

Therefore, such printing hammers are generally provided with rebound prevention devices such as springs, weights, or elastic shock absorbers to prevent the above-mentioned problems from occurring.

FIG. 1 shows an example of a printing mechanism in a conventional printer of this kind, where l is the printing paper attached to the platenco, 3 is the ink ribbon, tI is the type wheel, and the ink ribbon 3 side of the type wheel. Type letters (not shown) are provided in the figure.

S is a printing hammer device, A is a hammer shaft or plunger whose tip is directed toward the back of the type wheel, and 7 is a magnetic coil that causes the plunger 6 to perform a striking action. Further, - plunger O is equipped with a return spring g for returning plunger O to the return position as shown in the figure after printing.

In order to further prevent the printing land from occurring, a way 10 having an elastic buffer member 9 attached thereto is rotatably attached to the printing device 5 around a shaft.
At the hammer standby position, the rear end surface 6A of the plunger 6 is kept in contact with the buffer member 9. 7.2 is weight 10
The stopper 13 is a retaining spring for the weight 10.

In the printing mechanism of a printer configured in this way,
When the coil 7 is energized during printing, the plunger 6 moves toward the paper l on the platenco, and the type on the type wheel da is struck onto the paper l together with the ink ribbon 3, thereby printing. After that, when the coil coil is demagnetized, the plunger 6 is quickly returned to the standby position by the repulsive force of the return spring and the platenco.

At this time, in order to prevent the plunger O from performing a rebound operation, the rear end of the plunger 6 is brought into contact with the buffer member 9 of the weight IO, which is elastically supported by the spring 13, to absorb the repulsive force of the plunger B. It's like letting them do it.

However, in such a conventional printing hammer device ts, when the plunger O returns after printing, the plunger 6 is moved by the spring force of the return spring g and the repulsive force of the platen. As shown in Figure m/, since the weight 10 is rotated by geo-balancing from the standby position shown in the figure, the rear end corner of the plunger A comes into contact with the buffer member 9 obliquely, which is satisfactory. There was a risk that a proper buffering effect could not be obtained.

〔the purpose〕

It is an object of the present invention to eliminate the above-mentioned drawbacks, and to satisfactorily prevent rebound by bringing the rear end of the plunger into full surface contact with a buffer member provided on the weight during the return operation of the granger, thereby preventing the printer from making mistakes. To provide a printing machine capable of suppressing causes of damage to printing and type wheels.

〔Example〕

The present invention will be described in detail below based on the drawings.

FIG. 3 shows an embodiment of the present invention, where /j is a printing hammer device υ, and J is a weight member rotatable around an axis ll. In the weight member of this example, the portion facing the plunger rear end surface 6A has a rear end surface 6A.
``Two notched holes having a sufficiently larger area than A are provided, and an arm portion 2 having a spring force is provided in this notched hole.
2A to the weight member and the edge of the notch hole 2, 2
A holding member n connected at 7A is provided, and this holding member n
An elastic buffer member blade is provided.

Thus, the buffer member 3 is made swingable in the operating direction of the plunger 6 with the notch hole, the edge of 2/A, as a fulcrum by deflection due to the spring force of the arm uA.

Note that the other configurations are the same as in the example shown in FIG.

In the printing hammer device fJ(/s) configured in this way, when the plunger 6 that has finished printing tries to retreat beyond the υ standby position due to the spring force of a return spring (not shown), the rear end surface 6A of the plunger First, it comes into contact with the buffer member 23, and the repulsive force thereof begins to be absorbed by the buffer member 23.

However, the surplus repulsive force resists the spring force of the weight holding spring 13 and tries to rotate the way and the toe around the rotation axis /l. In this example, this surplus repulsive force is absorbed by the buffer member 3.
is transmitted to the weight 〃 through the arm portion uA of the holding member λU provided with the repulsive force, so the arm portion 2A having the repulsive force absorbs this surplus repulsive force and flexes, as shown in Fig. q. As shown, the buffer part 23 and the rear end surface 6A of the plunger 6 are maintained in a state where they make full surface contact. Thus, the buffer member 2
The combined effect of the elasticity of arm part 3, the spring force of arm part A, and the spring force of holding spring/3 can effectively suppress the rebound of the plunger base.

FIG. S shows another embodiment of the present invention, in which the holding member n of the buffer member 3 shown in FIG. 3 and its arm portion uA are both formed integrally with the weight member 30. In this case, the weight member 3θ itself may be formed of an elastic material. The rest of the configuration is the same as the example shown in FIG. 3, and the rebound suppressing operation is also the same.

〔effect〕

As described above, according to the present invention, in a printing hammer device having a plunger type solenoid, a device for preventing rebound of the plunger that occurs when the plunger returns to the standby position after a printing operation is installed to prevent the plunger from rebounding when the plunger returns to the standby position after a printing operation. The buffer member is in full contact with the end surface on the retreating side of the plunger, and the plunger is elastically supported so as to be able to maintain the above-mentioned full contact state with respect to the plunger that is further retreated from the standby position. Since the weight is elastically supported by the base so that the plunger can swing only in the backward direction, the repulsive force generated when the plunger returns is effectively absorbed and the rebound can be prevented. Misprinting and damage to the printing wheel can be suppressed.

In the above explanation, the case of a printer having a petal type type wheel has been described, but the application of the present invention is not limited to this type of printer, but can be widely applied to printers in which type is generated by a five-plunger type solenoid. Needless to say.

[Brief explanation of drawings]

Fig. 1 is a plan view mainly showing an example of a printing hammer device of a printer having a conventional type wheel and plunger type solenoid; Fig. 2 is a plan view showing a rebound prevention operation in the printing hammer device; FIG. 1 is a perspective view showing an example of the configuration of the printing hammer according to the invention; FIG. FIG. S is a diagram showing the structure of a weight of a rebound prevention device in another embodiment of the present invention. /... Paper, 2... Platen, 3... Ink ribbon, Da... Type wheel. S...Printing hammer device, 6...Plunger, 6A...Rear end surface, pulling coil. t...Return spring, 9...Buffer. lO... Weight, l/... Axis, /J... Stopper, 13... Holding spring, 13... Printing hammer device, 〃... Weight member. C/... Notch hole, C/A... Edge, n... Holding member. , uA...Arm portion, n...Buffer member, 3θ...Weight member. Patent applicant Canon Co., Ltd. Figure 5

Claims (1)

[Claims] A printing hammer that supports a plunger-type solenoid so as to be linearly reciprocated in its axial direction, and is capable of striking printed characters against the tip of the plunger of the solenoid, wherein the printing hammer makes surface contact with the rear end of the plunger when the plunger is at rest. and a support member that elastically supports the buffer member so that the buffer member is held in surface contact with the rear end during the return movement of the plunger. Hammer.