JPS6227992B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drum-type dot printer in which the center of a printing hammer is always struck against a printing dot on a printing base drum.

In general, a drum-type dot printer has a plurality of printing dots protruding from the outer periphery of a printing base drum, with the phases shifted in the axial and circumferential directions, and by rotating the printing base drum, a desired dot is positioned at the printing position. It is constructed so that a printing hammer hits the dots, and a dot matrix is printed on a recording paper inserted between the drum and the hammer.

In this type of printer, one printing hammer corresponds to a large number of printing dots, but since the position of the hammer hitting each dot is different, it is not possible to always hit the center of the hammer on the dot. The hammer had the disadvantage that it received a load at a position off center, shortening its life, and that the hammer was not supported in an unstable manner.

Furthermore, since a common hammer is used to strike many dots at different positions, it is necessary to make the hammer large, which makes the hammer heavy and difficult to operate at high speed, making it impossible to increase the printing speed. It was hot.

The present invention was made based on the above circumstances, and its purpose is to mount a printing hammer on a carrier and move the carrier forward and backward in parallel to the axis of the printing base drum so as to always maintain the center position of the printing hammer. The hammer hits the printing dots on the printing base drum, thereby extending the lifespan of the hammer and stabilizing its supporting condition.The hammer is also made smaller and lighter, enabling high-speed printing, and is simple in structure and easy to operate. Another objective is to provide a reliable drum type dot printer.

Hereinafter, details of the present invention will be explained based on illustrated embodiments.

First, the embodiment shown in FIG. 1 will be described.
FIG. 1 is a plan view of a drum-type dot printer. A U-shaped drum support fitting 2 is fixed to the inside of a base 1, and a shaft 4 of a marking drum 3 is attached to both sides of this metal fitting 2. Both ends are rotatably supported. A pulse motor 5 is fixed to the right outer side of the base 1. The shaft 6 of this motor 5 extends inside the base 1, and its center line is aligned with the shaft 4 of the stamping drum 3, and both shafts 4 and 6 are connected by a joint 7. Further, reference numeral 30 in FIG. 1 is a rotary power mechanism, which in this embodiment is composed of bevel gears 8 and 9 that mesh with each other. The input bevel gear 8 of the mechanism 30 is fixed to the shaft 6 of the motor 5, and the shaft 10 of the output bevel gear 9 is supported by a support 11 fixed on the base 1.
Both bevel gears 8 and 9 have the same number of teeth, and are adapted to rotate the shaft 4 of the marking drum 3 and the shaft 10 of the bevel gear 9 at the same speed. The axis 10 of the bevel gear 9 is perpendicular to the axis 4 of the printing stand drum 3, and
0 has a rotating cam 12 fixed thereto. A carrier 13 is mounted on the base 1 so as to be movable forward and backward in a direction parallel to the shaft 4 of the drum 3. A cam roller 14 is attached to one end of the carrier 13 on the cam 12 side.
is supported, and a compression coil spring 15 is connected between the other end of the carrier 13 and the right edge of the base 1.
is inserted. Shaft 16 of the cam roller 14
is parallel to the axis 10 of the cam 12, and the cam roller 14 is elastically abutted against the outer periphery of the cam 12 by the spring 15. The spring 15 is a cylindrical spring guide 17 fixed to the base 1.
supported within. The cam mechanism consisting of the cam 12 and the cam roller 14 together with the spring 15 constitutes carrier operating means.

On the outer periphery of the printing stand drum 3, a large number of printing dots 18 are arranged with phases shifted in the axial direction and the circumferential direction.
They are arranged in a so-called spiral pattern. At the front edge of the carrier 13 near the drum 3,
A large number of printing hammers 19 each handling the same number of printing dots 18 are arranged at equal intervals. Each printing hammer 19 is attached to a carrier 13 as shown in FIG.
is attached to a portion facing the stamp stand drum 3 so as to be able to move forward and backward toward and away from the stamp stand drum 3 (that is, in a direction orthogonal to the operating direction of the carrier 13). A nut 20 is screwed onto the rear end of the printing hammer 19, and the nut 20 is pushed from the front by a spring 21, so that the printing hammer 19 is always held at a position away from the printing base drum 3. Furthermore, electromagnetic plungers 22 corresponding to each printing hammer 19 are mounted on the carrier 13 in a staggered manner. The movable body 23 of the plunger 22 and the nut 20 are connected by a thin wire-shaped connecting rod 24,
By energizing the coil 25 of the plunger 22, the movable body 2
3 in the direction of the printing stand drum 3, the hammer 19 hits the printing dot 18 on the printing stand drum 3. Note that the movable body 23 is always urged in the direction opposite to the drum by the leaf spring 26.

The printing dots 18 provided on the printing stand drum 3 are
As shown in Fig. 3, at intervals of an angle θ in the direction of rotation,
And they are arranged at intervals of a in the axial direction. Further, each row of printed dots 18 is arranged with a different inclination by half a circumference, as shown in an expanded view in FIG. On the other hand, the cam 12 has a line-symmetrical shape as shown in FIG.
The radius decreases by a with each rotation. That is, when the maximum radius of the cam 12 is r, the radius at a position rotated by nθ from the maximum radius position is r−na. And cam 12
When the maximum radius position of the carrier 13 comes into contact with the cam roller 14, the carrier 13 is located at the rightmost position as shown in FIG. is positioned on the movement line of the printing hammer 19, that is, at a predetermined printing position.

Both ends of a shaft 28 of an ink roller 27 are rotatably supported on both sides of the drum support fitting 2, so that the outer periphery of the ink roller 27 is always in contact with the dots 18 of the printing stand drum 3.

Next, the operation of this dot printer will be explained. When the recording paper 29 to be printed is inserted between the printing base drum 3 and the printing hammer 19 and a printing command is given, the pulse motor 5 rotates in a fixed direction by an angle θ in response to this printing command, and at the same time each electromagnetic plunger 22 coils 25 are excited at a predetermined timing, and each printing hammer 19 hits a printing dot 18 on the printing stand drum 3. And stamp stand drum 3
Every half rotation, a paper feeding device (not shown) operates to feed the recording paper 29 one dot at a time, so that dot matrix printing is performed on the recording paper 29.

According to the above dot printer, the stamping drum 3
Since the and cam 12 are driven by the common motor 5, the configuration is simplified, and the drum 3 and carrier 1 are driven by the same motor 5.
It is also easy to time the operation with 3. The drum 3 and the cam 12 rotate at the same speed, and each time the drum 3 rotates by an angle θ, the next dot 1 is placed at the printing position.
8 appears shifted by a in the axial direction, but as the drum 3 rotates by θ, the carrier 13 also moves by a in the direction of the displacement of the dot 18, so the center of the hammer 19 is always , coincides with the printing dot 18 located at the printing position, and the center position of the printing hammer 19 can always hit the printing dot 18. Therefore, the hammer 19 always receives a load at the central position, resulting in a long life and a stable supporting state of the hammer 19. Also hammer 19
Since the off-center part is no longer needed, it is smaller and lighter, and the lighter the hammer, the easier it is to operate at high speeds, increasing printing speed.

In addition, although this invention is not particularly limited, as ink application means as in the embodiments,
Ink roller 2 instead of the conventional ink ribbon system
By adopting No. 7, it is possible to eliminate the trouble of having to frequently replace the ink ribbon.

Furthermore, the present invention is not limited to the above embodiments, and can be modified in various ways. For example, in the above-mentioned embodiment, the carrier operating means was constituted by a cam mechanism, but since the present invention described above has the constitution set forth in the claims, the carrier equipped with the printing hammer is moved parallel to the drum shaft. By moving forward and backward, the center position of the printing hammer can be aligned with the printing dot located at the printing position. This makes it possible to extend the life of the hammer and stabilize the supporting state of the hammer, and also to make the hammer smaller and lighter, thereby increasing the printing speed. Since the operating means of the carrier is mechanically interlocked via a rotational transmission mechanism with the shaft of a motor that rotationally drives the stamping platform drum, the stamping platform drum and the carrier can be driven by a common motor. As a result, there is no need for a special drive device exclusively for the carrier, the structure is simplified, and the operation timing of the printing stand drum and the carrier can be easily determined, so that reliable operation can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing one embodiment of the present invention, and FIG.
The figure is an enlarged cross-sectional view of a part of the same embodiment.
The figure is an enlarged perspective view of a part of the same embodiment.
The figure is a partially exploded view of the stamping drum of the same embodiment, and FIG. 5 is a plan view showing the cam of the same embodiment. 3... Marker drum, 8, 9... Bevel gear, 12
...Cam, 13...Carrier, 18...Printing dot, 19...Printing hammer, 29...Recording paper, 30
...Rotary transmission mechanism.

Claims (1)

[Claims] 1. A plurality of printing dots are provided on the outer periphery of the printing drum, with the phases shifted in the axial and circumferential directions, and by rotating the printing drum, a printing hammer is hit on any dot, thereby creating a gap between the drum and the hammer. In a drum-type dot printer that prints dots on recording paper inserted into a printer, a carrier equipped with the printing hammer is provided so as to be able to move forward and backward in a direction parallel to the drum shaft, and a rotary transmission is connected to the shaft of a motor that rotationally drives the printing base drum. The input part of the mechanism is connected, and the output part of the rotary transmission mechanism and the carrier are located at the printing position and are arranged at an angle θ in the rotational direction and a distance in the axial direction, and are tilted half a turn at a time. In order to align the center position of the printing hammer with the printing dot formed by changing the printing dot, it forms a line-symmetrical shape corresponding to the printing dot, and the angle θ is set to the left and right from the maximum radius position.
A drum-type dot printer connected by a cam whose radius decreases by a each time it rotates.