JPH0128705B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a print head used in a wire dot printer, and more particularly to an improvement in a print head suitable for responding to changes in the stroke of a print wire up to the platen surface.

Printers that form patterns such as characters by a collection of dots formed by printing wires can produce many types of characters, and are extremely suitable and economical for applications requiring copying. In order to improve printing quality, it is necessary to make the wires thinner and increase the number of wires so that each wire can operate independently. In addition, as its use as a computer terminal is expanding, it is required to operate at high speed.

The conventional method will be explained with reference to FIGS. 1 to 4. FIG. 1 is a plan view illustrating a wire dot printer to which the present invention is applied, and FIG. 2 is a side view showing the printing magnet section of FIG. 1. 3 is a side view showing a guide frame portion of a printing head according to a conventional method, and FIG. 4 is a plan view showing a pin guide portion of FIG. 3. In the figure, 1 is the core, 2 is the coil, 3 is the armature, 3a is the holding part, 4 is the printing wire, 5
is a guide frame, 5a is a pin guide, 5b, 5
b-1 to 5b-24 are pin holes, 6 is a support spring, 7
a and 7b are magnetic path sections, 7c is a side magnetic path section, 8 is a permanent magnet, 9 is a frame, 10 is a platen, 11 is a printing paper, 12a and 12b are sprockets, 13 is a carrier, 15 is a guide shaft, and 16 is a Feed screw, 17 is a belt, 19 is a motor, 20 is an ink ribbon cassette, 20a is an ink ribbon, 21a
21a is the print head, 21a is the print magnet, l is the stroke, _l1 is the maximum stroke of each column, and _l2 is the minimum stroke of each column.

As shown in FIG. 1, the wire dot printer has a frame 9, on which a platen 10 is rotatably supported. A printing paper 11 is wrapped around the platen 10.
The printing paper 11 is sent in the direction of arrow A in the figure by sprockets 12a, 12b, etc. On the other hand, platen 1
0, that is, at the bottom in the figure, there is a guide shaft 1 with a carrier 13 provided parallel to the platen 10.
5, and the carrier 13 is slidably fitted into the feed screw 1, which is also provided parallel to the platen 10.
It is screwed together with 6. The feed screw 16 is connected to a motor 19 via a belt 17 or the like, and therefore, the feed screw 16 can move the carrier 13 in the directions of arrows C and D in the figure by rotating the motor 19 in forward and reverse directions. . An ink ribbon cassette 20 is mounted on the carrier 13, and an endless ink ribbon 20a is built into the cassette 20 with a portion thereof exposed to the platen 10 side. Also,
A print head 21 is installed in the carrier 13 surrounded by an ink ribbon cassette 20, and the print head 21 is provided with a plurality of print magnets 21a for forming prints by dots.

As shown in FIG. 2, the printing magnet 21a is
A coil 2 is wound around a core 1, and an armature 3 is arranged so as to come into contact with the core 1. A holding part 5 having a printing wire 4 fixed to the tip thereof is attached to the armature 3, and the armature 3 is elastically supported by a support spring 6, and one end of the support spring 6 is fixed to the magnetic path part 7a. ing. The magnetic path portions 7a and 7b are arranged so as to sandwich the magnet 8 therebetween and surround the core 1 and the armature 3 in a U-shape. Further, side magnetic path portions 7c that engage with both sides of the armature 3 with a gap protrude from the magnetic path portion 7a.

Therefore, when the printing magnet 21a is not operating, the armature 3 is attracted to the core 1 by the magnetic force of the permanent magnet 8.

With this configuration, if current is applied to the coil 2 of the printing magnet 21a of the printing head 21 so that the NS pole of the permanent magnet 8 and the pole of the core 1 are opposite to each other, the core 1 becomes an electromagnet and the permanent magnet 8 The armature 3 flies toward the magnetic path 7a, that is, upward in FIG. 2, due to the energy stored by the support spring 6. Then, the printing wire 4 also protrudes in the direction of arrow E in the figure, and the printing paper 1 on the platen 10 shown in FIG.
1 through the ink ribbon 20a, and printing is performed. When the power supply to the coil 2 is stopped, the electromagnetic force of the core 1 also disappears, and the armature 3 moves in the direction of arrow F in FIG. Return. In this way, while selectively driving the plurality of print magnets 21a in the print head 21, the print head 21 is moved along with the carrier 13 along the arrow C, as shown in FIG.
The printing operation is performed on the printing paper 11 by moving it in the D direction.

As shown in FIG. 3, in such a print head 21a, the tip of the print wire 4 is guided by a pin hole 5b of a pin guide 5a provided in a guide frame 5. As shown in FIG. 4, the pin holes 5b are arranged in two vertical rows of 12 each, and as the printing head 21 moves laterally, the printing wire 4 collects dots to form a pattern such as characters. This is to form a Therefore, depending on the position of the printing wire 4 guided by the pin hole 5b, the printing wire 4 may be deviated from the center facing the platen 10. On the other hand, since the outside of the platen 10 forms an arc, the distance from the pin guide 5a surface, that is, the second
The required stroke l of the printing wire 4 shown in the figure is different. As shown in FIG. 3, the minimum stroke of each row is l ₂ near the center, and the maximum stroke of each row is l ₁ at the upper and lower ends.

For this reason, there is a difference in the force of collision with the platen 10 when printing, which has the disadvantage that the upper and lower ends of the print become thinner and the print quality deteriorates. or,
Since the upper and lower printing wires 4 have to move over a longer distance than the others, the operating cycle becomes slower.As a countermeasure, the length of the printing wire 4 is adjusted according to the position of the pin hole 5b. A method has been proposed to change the pin guide 5 of the platen 10 and print head 21 in high-speed printers.
Since the gap with the b side is narrow (usually 0.5 mm or less), it is difficult to set up parts management during assembly.

SUMMARY OF THE INVENTION It is an object of the present invention to overcome the above-mentioned drawbacks and to provide a print head which changes the operating characteristics of the print magnet and thereby changes the stroke of the print wire.

The present invention provides a printing head having a platen, a plurality of printing magnets which face the platen with a gap therebetween and are configured by pairing an armature having a printing wire and an electromagnet that interrupts a magnetic path for the armature; a medium transfer section that transfers the medium set in the gap between the head and the platen;
In a printer comprising a drive unit that moves a printing head parallel to a platen, the distance is large so that the impact force of the printing wire is constant regardless of the distance from the outer curved surface of the platen to the tip of the printing wire. The printing head is opposed to the platen with a gap therebetween, and the printing magnet is changed so as to supply a large amount of energy to the printing wire, and the printing magnet having a small distance is changed so as to supply a small amount of energy to the printing wire. a printing head having a plurality of printing magnets configured by a pair of armatures having an armature and an electromagnet that interrupts a magnetic path for the armature; and a medium transfer section that transports a medium set in a gap between the printing head and a platen. In a printer consisting of a drive unit that moves the printing head parallel to the platen, a printing magnet with a large distance is used so that the impact force of the printing wire is constant regardless of the distance from the outer curved surface of the platen to the tip of the printing wire. This print head is characterized in that it supplies a large amount of energy to the printing wire, and a printing magnet having a small distance is changed so as to supply a small amount of energy to the printing wire. By doing so, printing quality can be improved.

An embodiment of the present invention will be described below with reference to FIG. FIG. 5 is a block diagram of print head control according to an embodiment of the present invention. In the diagram, 1-1 to 1-2
4 is a core, 2-1 to 2-24 are coils, 3-1 is an armature, 4-1 is a printing wire, 6-1 is a support spring, 14 is a control circuit, 14a-1 to 14a-
24 indicates a driver.

As shown in FIG. 5, the print head is driven by a control circuit 14 in which a selected print command is sent to a driver 14a--
1 to 14a-24, connect the power supply, and then connect the coils 2-1 to 14a of the printing magnet 21a.
This is done by energizing any one of 2-24.

As explained in Fig. 4, the arrangement of pin holes 5b is 12.
The printing wires 4-1 to 4-12 and 4-13 to 4-1 are arranged in two rows and are guided by these.
The printing magnet 21a corresponding to 4-24 is the fifth
As shown in the figure. However, printing wire 4-2 to 4-
24 is not shown in the figure. Therefore, core 1-1~1
The coils 2-1 to 2-24 wound around the coils 2-24 correspond to the pin holes 5b-1 to 5b-24.

Here, the number of windings of the coil 2 of the corresponding printing magnet 21a is changed depending on the size of the stroke, the number of windings is increased for a large stroke, and the number of windings is decreased for a small stroke. are doing.

That is, printing wires 4-1, 4-12, 4
-13, 4-24 is the maximum stroke of each row l ₁ , and printing wires 4-6, 4-7, 3-18, 3-1
9 is the minimum stroke l ₂ for each row, so for the former, coil 2 with a larger number of windings is used.
-1, 2-12, 2-13, 2-24, coils 2-6, 2- with a smaller number of windings than the latter
7, 2-18, and 2-19 are wound, and for a printing wire with an intermediate stroke, a coil is wound with the number of windings adapted to the size of the stroke.

As a result, the printing wire 4 of the printing magnet 21a equipped with the coil 2 with a large number of windings has a larger magnetomotive force than the printing wire 4 of the printing magnet 21a equipped with a coil with a smaller number of windings, so that the armature 3 is released earlier. Since the printing wire 4 pops out when the coil 2 is wound, the printing wire 4 can be driven corresponding to different strokes 1 by appropriately setting the number of windings of the coil 2, and high-quality printing can be obtained. Needless to say, the present invention can also be applied to a type of printing magnet that performs printing by attracting armature with an electromagnet.

A different embodiment will be described with reference to FIG. FIG. 6 is a printhead control block diagram according to a different embodiment. 2-1' to 2-2 in the diagram
4' is a coil, and 14-1 to 14-24 are non-magnetized plates. Also, the same parts as in FIG. 5 are indicated by the same symbols.

The difference between FIG. 6 and FIG. 5 of the above embodiment is that the coils 2-1 to 2-24 have the same specifications, but the core 1-
1 to 1-24 and amateurs 3-1 to 3-24 (however, 3-2 to 3-24 are not shown in the figure) are attached with a non-magnetized plate 1 whose thickness depends on the size of the stroke.
4-1 to 14-24 were installed. The non-magnetized plate is generally used for the purpose of reducing wear on the suction surface, preventing adhesion, etc., but in this embodiment, it also serves the purpose of changing the stroke l.
That is, amateur 3-1, 3-12, 3-1
3, 3-24 are the maximum strokes, and amateurs 3-6, 3-7, 3-18, 3-19 are the minimum strokes, so for the former, the thin non-magnetized plate 14-1 is used. ,14-12,14-1
3, 14-24, and thick non-magnetized plates 14-6, 14-7, 14-18, 14-19 are installed for the latter, and for intermediate stroke amateurs, it corresponds to the stroke size. A non-magnetized plate with a thickness of As a result, the armature equipped with the non-magnetized plate increases the deflection of the support spring 6, and therefore the energy stored in the support spring 6 increases, and at the same time, the force that tries to separate against the attractive force also increases, so the thick non-magnetized plate increases. It will be released faster than the amateur who attached the magnetized plate, and the printing wire will pop out. Therefore, by appropriately setting the thickness of the non-magnetized plate, high-quality printing similar to that of the previous embodiment can be obtained.

As explained above, according to the present invention, the timing of releasing the armature is adjusted by changing the stroke characteristics of the printing magnet in response to the stroke difference due to the position of the pin hole that guides the tip of the printing wire. When printed as a collection of dots, the upper and lower edges of characters, etc. do not become thinner, and high-quality printing can be obtained.

[Brief explanation of drawings]

FIG. 1 is a plan view illustrating a wire dot printer to which the present invention is applied, FIG. 2 is a side view showing the print magnet portion of the print head shown in FIG. 1, and FIG. 3 is a guide frame portion of the print head according to a conventional method. 4 is a plan view showing the pin guide section of FIG. 3, FIG. 5 is a block diagram of print head control according to an embodiment of the present invention, and FIG. 6 is a diagram of print head control according to a different embodiment. It is a block diagram. In the figure, 1, 1-1 to 1-24 are cores,
2, 2-1 to 2-24, 2-1' to 2-24' are coils, 3, 3-1 are amateurs, 4, 4-1 are printing wires, 5 is a guide frame, 5a is a pin guide, 5b , 5b-1 to 5b-24 are pin holes,
6, 6-1 are support springs, 7a, 7b are magnetic path parts, 7
c is a side magnetic path section, 8 is a permanent magnet, 14-1 to 14-
24 is a non-magnetized plate, and l indicates a stroke.

Claims (1)

[Claims] 1. Printing having a platen, a plurality of printing magnets configured by a pair of an armature that faces the platen through a gap and has a printing wire, and an electromagnet that interrupts a magnetic path for the armature. A printer comprising a print head, a medium transfer unit that transfers a medium set in a gap between the print head and the platen, and a drive unit that moves the print head parallel to the platen, the printer comprising the following steps: A printing magnet with a large distance supplies a large amount of energy to the printing wire, and a printing magnet with a small distance supplies a small amount of energy to the printing wire, so that the impact force on the printing wire is constant regardless of the distance to the tip of the printing wire. A print head characterized in that it can be changed to supply a print head. 2. The print head according to claim 1, wherein the energy is varied by changing the number of turns of the coil of the electromagnet of the print magnet. 3. Printing according to claim 1, characterized in that the energy is changed by changing the thickness of a non-magnetized plate installed between the armature of the printing magnet and the iron core of the electromagnet. Head.