JPS6330862B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printing mechanism for an impact type printer.

In this type of printing mechanism, there is a strong requirement that the impact force exerted by the hammer portion upon contact with the type head be variable. That is, the printing density becomes darker as the impact force per unit area becomes larger. (However, if the impact force exceeds a certain value, there will be almost no change.) Conversely, the lower the impact force, the longer the life of type. In addition, if the impact force is large, the type will sink into the paper, causing embossing on the paper, and in extreme cases, holes will be formed in the paper.

Therefore, in conventional printing mechanisms, in order to print with uniform density without damaging the life of the type, it is common practice to increase or decrease the impact force depending on the area of the type. It is also common practice to vary the overall impact force by, for example, However, in conventional printing mechanisms of this type, there has been a single portion that applies the impact force of the printing hammer to the type head. That is, the impact force is determined by the mass m of the hammer and the velocity v at the time of collision, but this m cannot be changed, and the velocity v has to be changed. This requires complex control such as changing the width of the pulse applied to the magnet that drives the hammer and changing the magnitude of the current. Further, for this reason, the characteristics of the hammer are required to have uniform performance over a wide area in accordance with the above-mentioned control. Furthermore, in order to change the speed v, the time required for one printing operation also changes.

The present invention includes dividing the hammer part of the printing mechanism,
The object of the present invention is to provide a device that eliminates the above-mentioned drawbacks by individually driving the impact force and can efficiently adjust the impact force with simple control.

According to the present invention, there is provided a printing mechanism comprising a type head which receives an impact force from the side opposite to the type face and performs printing by pressing the type face against a platen, and a printing hammer which applies an impact force to the type head. The movable part for applying an impact force to the type head of the printing hammer is divided into at least two parts that can be driven independently, and the printing pressure is adjusted by how many of the divided movable parts are driven. This results in a printing mechanism with a

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1a is a perspective view showing essential parts of an embodiment of the present invention. In FIG. 1a, one embodiment of the present invention includes a platen 2 around which a print medium (paper) 1 is wound, and a platen 2 that moves parallel to the platen 2,
The platen 2, which includes a carrier unit 3 for printing on the paper and a tractor unit 4 for mounting the printing paper 1, is driven by a pulse motor 5, and this driving force is transmitted by a motor gear 6 directly connected to the pulse motor 5.
from the platen gear 8 via the idle gear 7, and the platen 2 directly connected to the platen gear 8.
can be conveyed to. Note that this platen 2 has knob 1.
5 allows for manual rotation.

The truck unit 4 is driven as the platen 2 rotates, and this driving force is transmitted from a platen gear 9 directly connected to the platen 2 to a tractor gear 11 via an idle gear 10. The tractor unit 4 is configured to feed the paper by a predetermined amount using a tractor pin 50.

The carrier unit 3 is equipped with a type head 12, a split type print head 13, a ribbon cassette 14, and the like. This carrier unit 3 is provided with a guide bearing 16, and is mounted on a guide shaft 17 via this guide bearing 16. The carrier unit 3 is moved along the platen 2 by a spacing motor 18, and the driving force of the spacing motor 18 is transmitted through two wire ropes 19a and 19b. The wire ropes 19a, 19b are attached to a drive pulley 20 whose one end is directly connected to the spacing motor 18, and after being wound around the drive pulley 20 multiple times, the wire ropes 19a, 19b are attached to guide pulleys 21a, 22a, 21b, 22b attached to the frame. The other end is connected to the carrier unit 3 via guide pulleys 23a, 23b attached to the carrier unit 3 via the frame, and further via guide pulleys 24a, 24b attached to the frame.

The carrier unit 3 has various mechanisms mounted on a front casting 25. Although not shown in the drawings, the front casting 25 is provided with a rotary motor for rotationally driving the petal type type head 12 and a transducer for selecting type at the lower part of the rotating motor.
Further, this front casting 25 is provided with a perpendicular motor 28 for moving the petal type type head 12 up and down.

A card holder 43 is provided on the front casting 25, and this card holder 43 serves to hold down the paper 1 so that it does not run out of alignment with the platen 2.

Further, the front casting 25 is provided with a ribbon base (not shown), on which the ribbon cassette 14 is removably mounted.

As shown in FIG. 1B, the petal type type head 12 is composed of a large number of fingers 46, and each finger 46 is provided with type characters 47 in two upper and lower stages. The petal type type head 12 is provided with a hole 48 in the lower center and is configured to be replaceable.

The print head 13 is located at a position surrounded by the fingers 47 of the type wheel 12, and is located at a position where striking force can be obtained from the back surface of the type 47.

FIG. 2 shows the construction of a split print head 13 used in the first embodiment of the present invention. In FIG. 2, the print head of this embodiment has a structure similar to that of a dot head used in a so-called dot matrix printer, and when an electromagnetic magnet 51 is excited, an armature 52 is attracted and a wire 53 in contact with the armature 52 is It is configured to pop out and apply an impact force to the type head 12, and is configured to return to its original state by a wire reset spring 54 and an armature reset spring 55 after printing is completed. Since FIG. 4 is a cross-section, only two pairs of magnet-armature-wire combinations are shown in this printing head, but for example, seven magnets are arranged at equal intervals in the circumferential direction and are connected via a wire guide 57. do,
At the tip of the hammer, the wires are arranged in a vertical line, as shown in FIG. 3, for example. In this print head, the number of magnets to be energized is selected by a drive hammer selection circuit (described later) according to the size (shape) of the type according to a command from a control section (not shown) of the printing device, and the type head 12 is activated. It is possible to change the impact force when hitting.

FIG. 4 shows an example of a driving hammer selection circuit used in the present invention. In FIG. 4, this drive hammer selection circuit inputs a print code from a control unit (not shown) and can send out a plurality of outputs corresponding to the number of drive wires 53 (for example, 7) of the print hammer 13. A table 71, an AND gate group 73 that sends out the output of the character table 71, a pulse generation circuit 72 that controls the AND gate using a hammerstrope signal, and a pulse generation circuit 72 that is activated by a signal from the AND gate group 73 to control the printing head. The drive circuit 74 includes a drive circuit 74 for driving an electromagnetic magnet.

As shown in FIG. 5, the character table 71 is used to control the impact force when striking the type head 12 according to the type of printed characters. For example, in the case of printed characters M, W, and Since the printing area is large, the outputs 71a, 71b, 71c, 71 are used to drive the wires a to g.
The output signals of d, 71e, 71f, and 71g are selected. Printed characters B, D, E, G, $, &, %,
In the case of #..., the outputs for exciting the wires are 71a, 71b, 71c, 71e, 71f,
The output signal of 71g is selected, and the printed characters A, C,
In the case of F..., outputs 71a, 71c, 71d, 71e, 71g are used to excite the wires.
The output signals of are selected, and the printed characters I, e,
In the case of i, j, l, r, the output signals 71a, 71c, 71e, 71g are selected as the outputs for exciting the wires, and the printed characters:,”,!,...
In the case of..., the output for excitation is 71a,
71d and 71g are selected, and furthermore, in the case of printed characters . . . , , −, −, . 4th again
Referring to the figure, when the print code is input to the driving hammer selection circuit, the character table 71 selects output signals 71a to 71g based on the table, and outputs the output signals 71a, 71b, . . . , 71g to each AND gate group 73. Gates 73a, 73
b, ...supply to 73g. Pulse generation circuit 72
Then, a hammerstrope signal is input, and based on this, a pulse 72a having a predetermined time width suitable for excitation of the electromagnet is generated. AND gate 73 supplies output signals 71a to 71g from character table 71 to drive circuit group 74 when pulse 72a is input. In the drive circuit group 74, individual drive circuits 74a to 74g corresponding to printed characters are selectively operated, so that the corresponding electromagnetic magnets 51 are excited. This electromagnetic magnet 51 acts on an armature 52 to drive a wire 53 and apply a striking force to the back side of the type head finger.

The printed characters on the type head 12 thus struck are pressed against the platen 11 via the ink ribbon 38 and the paper 2, thereby transferring the ink to the paper in the shape of the printed characters.

Although one embodiment has been described above, it is clear that various changes can be made to the above embodiment without departing from the spirit of the invention. For example, as shown in FIG. 6, although a so-called cup-shaped type head is used in the print head of this embodiment, a daisy-shaped type head may be used instead. In other words, in FIG. 6, the type head 62 has type characters arranged at the tips of fingers 46 extending radially from the center, and the type is selected by a selection motor 61, and is divided into two or more parts. , the printing hammers 12, each of which can be driven independently, are positioned on the type and reflective side of the type head 62. It is clear that even with such a configuration, it is possible to obtain an impact force corresponding to the size of the characters as in the embodiment of the present invention. Further, in this embodiment, the present invention has been described in the case where the print head has seven movable parts, but the above effect can be obtained if the print head has at least two movable parts.

As explained above, in the present invention, the printing force can be easily adjusted by using a split type hammer in which the movable part is divided in the mechanism that prints by receiving an impact on the type and the reflective side and moves independently.

[Brief explanation of the drawing]

Fig. 1a is a perspective view showing an embodiment of the present invention, Fig. 1b is a partial sectional view showing main parts in an embodiment of the invention, and Fig. 2 is used in an embodiment of the invention. 3 is a front view showing the tip of the print head, FIG. 4 is a diagram showing a driving hammer selection circuit used in an embodiment of the present invention, and FIG. 5 is a diagram showing a drive hammer selection circuit used in an embodiment of the present invention. FIG. 6 is a diagram showing another embodiment of the present invention. 1... Print medium, 2... Platen, 3... Carrier unit, 4... Tractor unit, 5...
Pulse motor, 6... Motor gear, 7... Idle gear, 8... Platen gear, 9... Platen gear, 10... Idle gear, 11... Tractor gear, 12... Type head (cup shape), 13...
Printing hammer, 14... Ribbon cassette, 15...
Knob, 16a-16l...Guide bearing,
17a... Guide shaft, 18... Spacing motor, 19a, 19b... Wire rope, 2
0...Drive pulley, 21a, 21b, 22
a, 22b, 23a, 23b, 24b... Guide pulley, 25... Front caster, 43
...Card holder, 46...Finga, 47...
...Print, 50...Tractor pin, 51...Electromagnetic magnet, 52...Armature, 53...Wire, 54...Wire reset spring, 55...
... Armature reset spring, 56 ... Back stopper, 57 ... Wire guide, 58 ...
Ruby guide, 61...Selection motor, 6
2... Type head (daisy shape), 71... Character table, 72... Pulse generation circuit, 73... AND gate group, 73a-73g... AND gate, 74... Drive circuit group, 74a-74g... drive circuit.

Claims (1)

[Claims] 1. In a printing device in which a printing part carrier performs reciprocating motion along a platen, a printing type provided on the printing part carrier and having a printing part on a surface facing the platen and being hit by a back surface of the printing part. a dot head section which is provided on the back side of the type head and has a plurality of wires and is capable of performing dot matrix printing; and means for selecting the number of wires to be driven from among the number of wires to be driven, and printing the type to be printed by adjusting the impact force applied to the type head by the selected wires. Device.