JPS5840514B2 - drum dot printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drum-type dot printer that can print in the same manner even if the direction of rotation of the printing head drum is reversed.

A drum type dot printer has a large number of printing dots arranged on the outer periphery of a printing base drum at different positions in the axial and circumferential directions, and by rotating this printing base drum, a desired dot is positioned at the printing position, and the dot is printed on that dot. It is configured to hit a printing hammer to print dot matrix on recording paper inserted between the drum and the hammer.

Conventionally, the printing dots are arranged along a line parallel to the rotation axis, as shown in FIG. 1 (a partially expanded view of the printing drum).
They were arranged in a straight line at a constant angle α.

In the figure, 101 is a printing stand drum, and 102 is a printing dot.

However, in this type of dot printer, it is necessary to keep the rotation direction of the printing head drum constant, and a control means for this purpose is required.

The present inventor also proposed a drum-type dot printer in which a printing hammer is attached to a carrier, and this carrier is moved parallel to the drum axis in synchronization with the rotation of a printing base drum so that dots are always struck at the center of the printing hammer. However, when such a configuration is adopted, it is desirable to perform a printing operation when the carrier moves in either direction.

However, when the printing dots are arranged as shown in Figure 1, the positional relationship between the printing hammer and the printing dots varies depending on the direction of movement of the carrier, which makes it extremely difficult to control the printing timing. .

The present invention was made based on these circumstances, and
To provide a drum-type dot printer in which the positional relationship between a printing hammer and a printing dot is constant no matter which direction the printing drum is rotated, and the rotational direction and printing timing of the printing drum can be easily controlled. The purpose is to

Hereinafter, the present invention will be described in detail with reference to illustrated examples.

FIG. 2 is a plan view of a drum-type dot printer, and inside the base 1 there is a U-shaped drum support fitting 2.
is fixed, and the shaft 4 of the stamping drum 3 is fixed 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 the motor 5 extends inside the base 1 so that its center line coincides with the shaft 4 of the stamping drum 3, and the shafts 4 and 6 are connected by a joint 7.

Further, a bevel gear 8 is fixed to the shaft 6 of the motor 5.

This bevel gear 8 meshes with another bevel gear 9,
The shaft 10 of this gear 9 is connected to a support base 11 fixed on the base 1.
is supported by

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 shaft 10 of the bevel gear 9 is perpendicular to the shaft 4 of the marking drum 3, and a rotary cam 12 is fixed to the shaft 10.

A carrier 13 is mounted on the base 1 so as to be movable forward and backward in a direction parallel to the axis 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 inserted between the other end of the carrier 13 and the right edge of the base 1.

The axis 16 of the cam roller 14 is parallel to the axis 10 of the cam 12, and the cam roller 14 is rotated by the spring 15.
It is elastically pressed against the outer periphery of 2.

The spring 15 is supported within a cylindrical spring guide 17 fixed to the base 1.

The pulse motor 5, shaft 6, bevel gears 8, 9,
A carrier drive mechanism is formed by the shaft 10, cam 12, cam roller 14, and compression coil spring 15, and the carrier 13 is moved in synchronization with the rotation of the printing stand drum 3.

On the outer periphery of the printing stand drum 3, a large number of printing dot rows 18 are provided at equal intervals in the axial direction.

FIG. 3 is a developed view showing an arbitrary printed dot row 18, and as shown in this figure, the printed dot row 18 is composed of two dots 18a continuous in the circumferential direction, and each dot row 18a is partitioned. , print dots 18 within the dots 18a on both sides of any boundary line parallel to the axis of rotation.
b are arranged line-symmetrically.

In this actual case, each printed dot row 18 is composed of two printed dots 18a, but the number of dots in the center and outside of one dot row may be an even number.

Each of the printed dots 18a has a linear shape,
The boundary 81 has an angle β with respect to L.

The printing driver N 8b in each printing dot train 18a is the fourth
As shown in the figure, they are arranged at intervals of angle θ in the rotational direction and at intervals of a in the axial direction.

A large number of printing hammers 19 corresponding to each printing dot row 18 are arranged at equal intervals on the front edge of the carrier 13 near the printing base drum 3.

As shown in FIG. 5, each printing hammer 19 is attached to a portion of the carrier 13 that faces the printing stand drum 3 so as to be able to move forward and backward in a direction toward and away from the printing stand drum 3 (that is, in a direction perpendicular to the operating direction of the carrier 13). has been done.

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.

Further, 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, and by energizing the coil 25 of the plunger 22 and moving the movable body 23 in the direction of the printing stand drum 3, The hammer 19 hits any dot 18b located at the printing position.

The movable body 23 is always urged in a direction opposite to the drum 3 by a leaf spring 26, and resiliently holds the printing hammer 19 at the illustrated position away from the printing base drum 3.

On the other hand, as shown in FIG. 6, the cam surface 12a of the rotating cam 12 is plane symmetrical with respect to the plane A that includes the rotation axis, and each time it rotates by an angle θ to the left or right from the maximum radius position P, the cam surface 12a moves toward the rotation axis by a. It's starting to get closer.

Therefore, when the maximum radius of the cam 12 is γ, the distance from the rotating shaft at a position away from the maximum radius position P by an angle nθ is γ-na.

The maximum radius position P of the rotating cam 12 is the cam roller 14.
2, the carrier 13 is in the rightmost position shown in FIG.
9, 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 a 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 rotates in a fixed direction by an angle θ in response to this printing command, and at the same time each electromagnetic plunger 22 The coils 25 are excited at a predetermined timing, and each printing hammer 19 hits a printing dot 18b on the printing stand drum 3.

Each time the printing base drum 3 makes a 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 drum-type dot printer, the stamping drum 3
Each time the dot N8b rotates at an angle of θ, the next dot 18b appears at the printing position shifted by a in the axial direction, but while the printing stand drum 3h rotates at an angle of θ, the carrier 13 also moves by a in the direction of the displacement of the driver N8b. Therefore, the center position of the printing hammer 19 and the printing dot 18b located at the printing position are aligned, and the printing hammer 19 always strikes the dot 18b at the center position.

According to this printer, the dot oval paper 18 on both sides of the boundary line dividing each dot oval paper 18a is
By arranging the printing dots 18b in a line symmetrically, the positional relationship between the printing hammer 19 and the printing dots 18b is constant no matter which direction the printing stand drum 3 is rotated, and the rotation of the printing stand drum 3 is Direction and printing timing can be easily controlled.

Furthermore, printing can be performed even when the carrier 13 moves in either direction, thereby increasing printing efficiency.

As described in detail above, according to the drum-type dot printer of the present invention, the printing dot row is made up of an even number of dots continuous in the circumferential direction, and at least one dot parallel to the rotation axis partitions each dot oval. By arranging the printing dots in the small rows of dots on both sides of one boundary line symmetrically, the positional relationship between the printing hammer and the printing dots can be maintained even when the printing base drum is rotated in either direction. The rotational direction of the printing drum and the printing timing can be easily controlled.

In particular, the printing dots in the small rows of dots on both sides of an arbitrary boundary line parallel to the rotation axis that divides each dot koban are line-symmetrically arranged, and the printing hammer is attached to the carrier. The carrier is provided so as to be movable back and forth in a direction parallel to the axis of the printing stand drum, and is operated in synchronization with the rotation of the printing stand drum to align the center position of the printing hammer with the printing dot located at the printing position. By connecting the carrier to the carrier drive mechanism, the printing operation can be started in either direction from the arbitrary boundary line position, and the printing hammer can be made smaller and lighter to increase the printing speed.

Note that the present invention is not limited to the above-mentioned actual case and can be modified in various ways.

For example, each row of printed dots may be arranged in a sinusoidal curve as shown in FIG. 7, and the shape of the printed dots can also be modified as appropriate.

[Brief explanation of the drawing]

FIG. 1 is a developed view showing the arrangement of printing dots in a conventional printer, FIGS. 2 to 6 show an embodiment of the present invention, and FIG. 2 is a partially sectional plan view, and FIG. 3 is a developed view showing the arrangement of printed dots, FIG. 4 is a perspective view showing an enlarged portion of FIG. 2, FIG. 5 is a sectional view showing an enlarged portion of FIG. 2, and FIG. Figure 6 is a plan view of the rotating cam, and Figure 7 is a plan view of the rotating cam.
The figure is a developed view showing the arrangement of printed dots in another embodiment of the present invention. 3... Marking stand drum, 4... Drum shaft,
5...Pulse motor, 6...Axis, 8,
9...Bevel gear, 10...Shaft, 12.
...Cam, 13...Carrier, 14...
...Cam roller, 15...Compression coil spring, 18...Printed dot row, 18a...
...Printing dot oval, 18b...Printing dot, 19...Printing hammer 29...Recording paper.

Claims (1)

[Scope of Claims] 1. Rotate the printing base drum having a row of printing dots on the outer periphery to position any printing dot at the printing position, and hit the printing hammer on the dot to create an intervening device between the printing base drum and the printing hammer. In a drum-type dot printer that performs dot matrix printing on recording paper inserted into the printer, the printing dot row is made up of an even number of oval dots continuous in the circumferential direction, and at least one dot parallel to the axis of rotation separates each oval dot. A drum-type dot printer characterized in that printed dots in small rows of dots on both sides of a boundary line are arranged symmetrically. 2. Rotate the print base drum that has a row of print dots on its outer periphery to position a desired print dot at the printing position, hit the print hammer on the dot, and place a dot on the recording paper inserted between the print base drum and the print hammer. In a drum-type dot printer that performs matrix printing, the printing dot row is composed of an even number of oval dots continuous in the circumferential direction, and with respect to an arbitrary boundary line parallel to the rotation axis that partitions each oval dot, The printing dots in the small rows of dots on both sides are arranged line-symmetrically, and the printing hammer is mounted on a carrier,
This carrier is provided so as to be movable back and forth in a direction parallel to the axis of the printing stand drum, and a carrier drive mechanism is operated in synchronization with the rotation of the printing stand drum to align the center position of the printing hammer with the printing dot located at the printing position. A drum-type dot printer, characterized in that the above-mentioned carrier is connected to the dot printer.