JPH0829610B2 - Small printer - Google Patents

Description

The present invention relates to a small printer.

[Prior Art] Conventionally, in a small printer of this type, in the sectional shape of the type wheel shaft, the inclination of the surface of the concave portion into which the type wheel spring falls, which surface precedes the rotation direction of the type wheel shaft, is constant regardless of the depth of the concave portion. Further, the inclination of the convex portion of the type ring spring engaging with the surface of the concave portion was also constant.

Further, the recess provided in the character wheel shaft maintains the integrity of the character wheel shaft and the character wheel until the desired character character arranged on the character wheel is stopped at the printing position in the character selection step. Exists only to position, and
Therefore, the number of recesses was limited to one.

[Problems to be Solved by the Invention] Conventionally, as shown in FIG. 4 (a), the sectional shape of a type wheel shaft is such that the surface of the recess on the side where the type wheel spring falls is the direction in which the type wheel spring presses the type wheel shaft. Parallel to that, and the slope of the convex part of the type ring spring is also parallel to that surface, and when the type ring spring falls into the concave part of the type wheel shaft, the step difference of the concave part is suddenly dropped, causing a large shock and accompanying noise. The wear of the type ring spring was also great. Also, as shown in FIG. 4 (b), the surface of the type wheel spring on the side where it falls is not parallel to the direction in which the type wheel shaft of the type wheel spring is pressed, and the type ring spring slides down along that surface. In the case of, when the type ring spring falls to the bottom of the recess, the type ring is positioned by the radius of the bottom of the recess and the tip radius of the type ring spring, so accurate position accuracy cannot be obtained and the selection function It was a factor that caused the decrease.

Further, conventionally, the recess provided in the type wheel shaft is only one place for maintaining the integrity of the type wheel shaft and the type wheel in the selection process, and the type ring spring force is used to speed up printing. Therefore, the noise when the type wheel spring falls into the recess of the type wheel shaft is increased, and the driving force of the type wheel shaft is also increased, resulting in a large power consumption.

An object of the present invention is to solve the above-mentioned drawbacks and to provide a small printer with low noise, excellent selection function, and low power consumption.

[Means for Solving the Problem] In the present invention, the surface of at least one of the concave portion of the type wheel shaft and the convex portion of the type wheel spring that precedes the rotation direction of the type wheel shaft is composed of at least two surfaces. It is characterized by

Further, the type wheel shaft has a plurality of recesses.

[Operation] In the present invention, when the convex portion of the type ring spring falls into the concave portion of the type ring shaft, the portion of the concave portion near the outer periphery of the type ring shaft slides down along the slope of the concave portion or the convex portion of the type ring spring,
After that, since it drops to the bottom of the concave portion and engages, the falling speed of the convex portion of the type ring spring is reduced, and it is provided separately from the concave portion of the type ring shaft that maintains the integrity of the type ring shaft and the type ring in the selection process. Since the convexity of the character ring spring falls into the concave portion and the force of withdrawal acts on the concave portion, the integrity of the character wheel shaft and the character wheel in the returning process is improved by the smaller force of the character wheel spring, so that noise reduction can be achieved. Further, since the type ring spring convex portion that has fallen into the concave portion that maintains the integrity of the type ring shaft and the type ring in the selection step is positioned by the end faces of the concave portion and the type ring spring convex portion, accurate position accuracy can be obtained. Is achieved by a plurality of recesses provided in the type wheel shaft,
The smaller the power of the type wheel, the smaller the spring force of the type wheel, the lower the power consumption and the speed of the type wheel.

Example An example according to the present invention will be described.

1) FIG. 1 is a detailed view showing an embodiment of the structure of the recess of the type wheel shaft according to the present invention.

A concave portion 1a of the type wheel shaft 1 that makes the type wheel shaft 1 and the type wheel 3 unity in the selection process, and a convex portion 2a of the type wheel spring 2
The recessed portion 1a of the character type wheel shaft 1 has a slope 1d on the opposite side of the sloped surface on the side where the protrusion 2a of the character type wheel spring 2 falls.
The angle formed between and is θ1 on the slope 1b close to the center of the shaft and θ2 on the slope 1c close to the outer circumference of the shaft.
It is set larger than 1.

In addition to the recessed portion 1a, an auxiliary recessed portion 1e is provided at a position of an angle θ5 preceding the recessed portion 1a in the rotational direction of the type wheel shaft 1.

Hereinafter, the present embodiment will be described with reference to FIG. 2 mainly while explaining the operation around the type wheel shaft (selection step, return stroke).

The type wheel spring 2 is incorporated in the type wheel 3 and is shown in FIG. 2 (a).
In the standby state shown in, the convex portion 2a is the concave portion 1a of the type wheel shaft 1.
The type wheel shaft 1 and the type wheel 3 are made integral.

The type wheel 3 has a plurality of type characters 3a on the outer circumference, a ratchet 3b corresponding to each type character 3a on the side surface, and a reset tooth 3c outside the rotation locus of the ratchet 3b.

The selection claw 4 is rotatably supported by the selection claw shaft 5 and is rotatable. In the selection step, when the trigger coil 6 is energized, the selection claw 4 rotates in the direction of the arrow B and engages with the ratchet 3b.
In the returning process, the ratchet 3b rotates in the direction of arrow C.
Also, the structure is such that the engagement with the reset teeth 3c is released.

When the printer starts to operate in response to the print command, the selection claw 4 rotates in the direction of arrow C, and the tip 4a of the selection claw 4 and the type wheel 3 are printed.
Immediately after being disengaged from the reset tooth 3c, the type wheel 3 starts to rotate in the direction of arrow A while maintaining the integrity with the type wheel shaft 1, so that the tip 4a of the selection claw 4 gets over the reset tooth 3c. . After that, the selection claw 4 pivotally returns to the standby position,
Enter the character selection process.

When entering the character selection step, the type wheel 3 continues to rotate while maintaining its integrity with the type wheel shaft 1, and the desired type character on the type wheel 1 is printed.
When the 3a rotates to the print position, the trigger coil 5 is energized. By electrification, the selection claw 4 rotates in the direction of arrow A and engages with the ratchet 3b of the type wheel 3. As a result, the type wheel 3 stops, but the type wheel shaft 1 continues to rotate, so that the convex portion 2a of the type wheel spring 2 slips out from the concave portion 1a of the type wheel shaft 1 and the type wheel shaft 1 and the type wheel 3 are integrated. Is lost and the state shown in FIG.

The printing wheel shaft 1 rotates until the desired printing characters 3a on the printing wheels 3 of each digit arranged in parallel are all arranged at the printing position, and the printing process starts.

When the printing process is completed, the return process is started. In the return process, the selection claw 4 is disengaged from the ratchet 3b and the type wheel shaft 1 starts to rotate again, but the type wheel 3 and the type wheel shaft 1 are restarted.
Is due to the frictional force generated by the spring force of the type ring spring 2,
Attempt to follow the rotation of the type wheel shaft 1 in the direction of arrow A. However, when attempting to achieve high-speed printing, the speed of the returning process is fast, and the type wheel 3 cannot follow the movement of the type wheel shaft 1 due to its inertial weight only by the conventional frictional force, and the phase is gradually delayed. become. Then, as shown in FIG. 2 (c), the type wheel 3 is attached to the type wheel shaft 1 with respect to the type wheel spring 2.
The phase is delayed until the convex portion 2a of the concave portion 2a falls into the concave portion 1e provided in the type wheel shaft 1.

When the convex portion 2a of the type wheel spring 2 falls into the concave portion 1e, the type wheel shaft 1 continues to rotate, and the friction between the type wheel spring 2 and the type wheel shaft 1 is maintained between the type wheel 3 and the type wheel shaft 1. In addition to power
Since a force is exerted that causes the type wheel spring 2 to come out of the auxiliary recess 1e, the type wheel 3 rotates while recovering its integrity with the type wheel shaft 1.

As shown in FIG. 6, the reset tooth 3c of the type wheel 3 has the reset tooth 3c of the type wheel 3 which has recovered its integrity with the type wheel shaft 1.
Although the character wheel shaft 1 continues to rotate, the convex portion 2a of the character wheel spring 2 comes out of the concave portion 1e, engages with the concave portion 1a again, and returns to the standby state.

At this time, the convex portion 2a of the type wheel spring 2 does not fall into the concave portion 1a at once, but as shown in FIG. 2 (e), the portion of the concave portion 1a near the outer circumference of the type wheel shaft 1 is gently along the slope 1c. It slides down and then falls to the bottom of the recess 1a, but the falling speed becomes slower and the impact becomes smaller.

In this embodiment, θ1 = 55 °, θ2 = 120 °, and slopes 1c and 1
b is a type wheel spring 2 from the outer periphery of the type wheel shaft 1 to the recess 1a.
As a result, the sound pressure level was reduced by about 3 dB and the positional accuracy of the type wheel and the type wheel shaft was improved. The effect is another θ1 satisfying θ1 <θ2,
It is also achieved by the combination of θ2.

The depth of the recess 1e is about 1/3 of the depth of the recess 1a,
As a result of the angle θ5 formed by the recesses 1a and 1e being set to about 30 °,
Although the result that the printing speed is about twice as high as that of the conventional technique is obtained, the shape of the concave portion 1e, θ5, and the number can be freely set.

2) FIG. 3 shows another embodiment of the present invention different from the first embodiment, and is a detailed view showing the shapes of the concave portion 1a of the type wheel shaft 1 and the convex portion 2a of the type wheel spring 2.

The angle formed between the slope 2c of the recess 2a of the type wheel shaft and the slope 2c on the opposite side of the recess 2a of the type wheel spring 2 is θ4 at the tip 2b of the protrusion 2a and θ3 at the root 2c. It consists of two surfaces and is set to θ4> θ3.

 The operation is similar to that of the first embodiment, and the description is omitted.

[Effects of the Invention] As described above, the present invention has the following effects.

The speed at which the type ring spring falls into the recess of the type wheel shaft can be slowed down, and the positional accuracy of the type wheel shaft and the type wheel in the selection process is improved, resulting in lower noise, improved durability, and improved selection function. Can be measured.

In addition, the multiple recesses on the type wheel shaft improve the ability of the type wheel to follow the type wheel shaft during the restoration process, and the printer speed can be increased with a smaller type ring spring force, while also reducing noise and power consumption. Can be measured.

[Brief description of drawings]

FIG. 1 is a partially enlarged view showing the first embodiment of the present invention. 2 (a) to 2 (e) are sectional views for explaining the operation of the first embodiment of the present invention. FIG. 3 is a partially enlarged view showing the second embodiment of the present invention. 4 (a) and 4 (b) are sectional views showing a conventional technique. 1 …… Type ring shaft 2 …… Type ring spring 3 …… Type ring 4 …… Selection claw 5 …… Selection claw axis 6 …… Trigger coil

Claims (2)

[Claims] 1. A character ring having a plurality of characters arranged on its outer circumference and having ratchet teeth corresponding to the character, a character ring spring incorporated in the character wheel, having a convex portion, and having elasticity, and the character character. A type wheel shaft having a concave portion that engages with the convex portion of the ring spring and rotating in the same direction during one cycle, and a selection claw having an engaging portion with the ratchet teeth, which rotates the type wheel. In a type wheel selection type small printer that engages a selection claw with the ratchet teeth and selects and prints a desired type, in at least one shape of the recess of the type wheel shaft or the protrusion of the type wheel spring, the type character A small printer characterized in that the surface of the wheel axle preceding the rotational direction is composed of at least two surfaces. 2. The small printer according to claim 1, wherein the type wheel shaft has a plurality of recesses.