JP3239278B2 - Print head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire dot type print head.

In a print head of this type, a ribbon guide and a mask are generally mounted on a carrier for use. Also, high performance to prevent ribbon catching trouble caused by deviation of wire retraction timing.
Moving to higher priced heads.

[0003]

2. Description of the Related Art FIG. 4 is a perspective view showing the structure of a main part of a conventional printer using a ribbon guide and a mask. In the drawing, reference numeral 1 denotes a print head having a nose portion 1a for guiding a dot wire; The ribbon guide 3 is a mask. Each of these members is mounted on a carrier 4, and the carrier 4 is
It is guided by guide shafts 5 and 6, and reciprocates along a platen (not shown).

[0004] ribbon guide 2B near the nose portion 1a, opposite state between the mask 3 and the platen 7 is as shown in FIG. 5,
The ribbon 101 (which is fed from a ribbon cassette (not shown)) is guided by a ribbon guide 2B, and the mask 3 is wound around a platen 7 and fed by a recording paper (medium) 10
The dirt by the zero ribbon 101 is prevented.

The configuration and operation of the print head 1 will be described with reference to FIG. 6 taking an electromagnetic release type as an example. FIG 6 (A) is a sectional view of the head, FIG. 6 (B) is a layout view of each printing element. The print head 1 includes a yoke 31 for forming a magnetic path, a permanent magnet 32 disposed in the middle of the yoke 31, a coil 33 wound around the yoke 31, and a yoke 31 near the coil winding portion. A plurality of printing elements 3 each comprising a movable portion comprising an armature 34 facing the armature, a beam 36 connected to the armature 34 and having a dot wire 35 fixed at the tip thereof, and a spring 37 for urging the movable portion in the printing direction.
8 and moves with the carrier 4 to operate at a predetermined time to perform printing. The printing procedure is as follows.

During non-printing, the coil 33 is not energized, and the armature 34 is moved by the permanent magnet 32 to the yoke 3.
1, is attracted to the yoke 31 by the attraction force of the magnetic flux formed through the armature 34. In this state, the dot wire 35 guided to the nose portion 1a is retracted from the platen 7 by a predetermined amount.

At the time of printing, the coil 33 of a predetermined printing element is energized for a predetermined time at a predetermined time. As a result, a part of the magnetic flux generated by the permanent magnet 32 is canceled and the attraction force is reduced, the movable portion is rotated in the printing direction by the urging force of the spring 37, and the dot wire 35 is connected to the ink ribbon 101, the recording paper 1 and the like.
The printing is performed by hitting the platen 7 via 00. At the time of completion of the printing, the power supply to the coil 33 is stopped, and the armature 34 is attracted to the yoke 31 again.
The operation of the wire is the same in other electromagnetic suction type print heads and print heads driven by piezoelectric elements or the like.

[0008]

However, the above conventional method has the following various disadvantages. (1) Since a ribbon guide and a mask are required, the number of parts around the head is increased. (2) Strict synchronization is required so that the ribbon moves when the leading end of the wire becomes the same as the front end surface of the nose portion when the dot wire is pulled in. Therefore, high-precision control is required in setting the margin. (3) Head gap (gap between platen and print head)
Adjustment man-hours cannot be reduced.

According to the present invention, there is provided a print head capable of reducing the number of components around the head, realizing a sharp reduction in hooking due to interference between a dot wire and a ribbon, a shift in operation timing, and a reduction in head gap adjustment man-hours. It is intended to provide.

[0010]

In order to achieve the above object, according to the present invention, a plurality of printing elements each having a dot wire are provided, and a pin guide for guiding the tip of each dot wire is provided at the front. In a print head having a nose portion, a ribbon guide groove having a depth of δ ₂ is formed at the tip of the nose portion, and a
Our dented only δ ₁ from the ribbon guide groove front
In addition, the upper and lower pin guides at the front of the nose
Element is referred to as configuration, wherein it is in the front and the surface of the pin guide. FIG. 1 is a principle diagram of the present invention ,
In the figure, 11a is a nose portion, 18 is a groove for ribbon guide, 20
Is a dot wire, and 21 is a pin guide.

[0011]

[0012]

[0013]

[Action] of the tip in the depth is formed in the nose section 11a [delta] ₂ ribbon guide groove 18 guides the ribbon so as to avoid contact with the medium other than the printing operation. Nose part 1
The portion protruding from the ribbon guide groove 18 at the tip of 1a guides the medium. Therefore, the ribbon guide and the mask near the nose are not required, and the number of parts around the head can be reduced and the cost can be reduced.

[0014] wa ear retraction space [delta] ₁ (distance between the ribbon and the nose portion front end being guided by the groove ribbon guide)
As a result, the interference between the dot wire 20 and the ribbon and the hooking due to a shift in the operation timing are sharply reduced. further,
A synchronization margin between the sliding of the dot wire 20 and the driving of the ribbon can be secured. In addition, the top and bottom of the pin guide at the front of the nose
Is made flush with the front of the pin guide.
Thus, the tip of the dot wire 20 can be easily polished.

[0015]

EXAMPLES Hereinafter, an embodiment of the present invention in conjunction with FIGS.

FIG. 3 is a perspective view showing the main structure of the printer of the present embodiment. In the figure, reference numeral 11 denotes a release type print head having a nose portion 11a, and reference numeral 12 denotes a ribbon guide corresponding to a conventional ribbon guide 2A.
Carrier 15 guided along the platen guided by 14
It is installed in. As is apparent from this figure, in the present invention, the mask and the ribbon guide near the nose are not used.

FIG. 2 shows a front structure of the nose portion 11a of the print head 11. As shown in FIG. 2 (A) is a perspective view, FIG. 2 (B) is a plan view. At the front end of the nose portion 11a, a step 16 having a depth δ is formed.
A ribbon guide groove 18 recessed by a smaller δ ₂ is formed. The step 16 is formed by vertically penetrating the front end of the nose portion 11a, and a curved surface processing 19 is applied to a corner of the surface of the projection 17 and a corner of the surface of the ribbon guide groove 18. Incidentally, the upper and lower through formation of the step 16 facilitates the dot wire tip polished in the arrow A direction in FIG. 2 (A).

A print head 1 is provided on the front surface of the nose 11a.
1 is provided with a pin guide 21 for guiding a plurality of dot wires 20 respectively provided on a plurality of printing elements similar to the conventional printing element in a predetermined arrangement.
The front surface of the first 1 is δ ₁ (= δ−δ) from the ribbon guide groove 18.
₂ ) only indents and coincides with the bottom surface of step 16.
The step 16 is formed in a wider range than the pin guide 21.

The front structure of the nose portion of the present embodiment is constructed as described above.
0, and the ribbon guide groove 18 formed in the protrusion 17 by δ ₂ from the surface thereof is
Is guided so as to avoid contact with the recording paper except during the printing operation. Therefore, a ribbon guide and a mask near the nose, which are conventionally required, are not required, and the number of parts around the head can be reduced and the cost can be reduced.

Further, since a wire retreat space δ ₁ is secured between the bottom surface of the step 16 (the front surface of the pin guide 21) and the surface of the ribbon guide groove 18, interference between the dot wire 20 and the ribbon 101 is prevented. In addition to drastically reducing the hooking due to a shift in the operation timing, a margin for synchronizing the sliding of the dot wire and the driving of the ribbon can be secured, and the degree of freedom of the setting angle of the dot wire increases.

By appropriately setting the depth δ of the step 16, the head gap can be ensured only by pressing the projection 17 against the platen via the recording paper, so that the man-hour for adjusting the head gap can be reduced. .

The running recording paper 100 is guided to the projection 17 at four points as described above, and the corner of the surface of the projection 17 is curved so that the medium traveling resistance is small.
Since the ribbon 101 is also guided by the ribbon guide groove 18 whose corner is curved, the running resistance of the ribbon is small. In any case, if you apply Teflon coating on the guide surface,
Running resistance is less.

[0023]

As described above, according to the present invention, the following various effects can be obtained. (1) The size and weight of the printer can be reduced by reducing the number of parts. (2) Costs can be reduced because the number of assembly and adjustment steps is reduced. (3) Ribbon catch is greatly reduced. (4) The degree of freedom of the setting angle of the dot wire is increased, and the C-shaped arrangement can be realized. (5) By forming the step of δ vertically through the front end of the nose portion, the front end of the dot wire can be easily polished.

[Brief description of the drawings]

FIG. 1 is a principle view of the present invention, in which a front portion of a nose portion is formed.
Is shown.

FIGS. 2A and 2B are explanatory diagrams of a front structure of a nose portion of a print head according to an embodiment of the present invention. FIG. 1A is a perspective view, and FIG. 1B is a plan view.

FIG. 3 is a perspective view showing a main structure of the printer according to the embodiment of the present invention.

FIG. 4 is a perspective view showing a main part structure of a conventional printer.

FIG. 5 is a side view showing a state in which a ribbon guide mask and a platen of a conventional printer are opposed to each other.

FIG. 6 is a structural explanatory view of a conventional print head, and FIG.
FIG. 6B is a sectional view, and FIG. 6B is a layout view of each printing element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Print head 11a Nose part 16 Step 17 Projection 18 Ribbon guide groove 19 Curved surface processing 20 Dot wire 100 Recording paper (medium) 101 Ribbon

Claims (1)

(57) [Claims] A plurality of printing elements each having a dot wire (20);
In a print head having a nose portion (11a) having a pin guide (21) at a front portion for guiding a tip portion of the nose portion (11), a ribbon guide groove (18) having a depth of δ ₂ is formed at the tip of the nose portion (11a). ), And the front surface of the pin guide (21 ) is formed with the ribbon guide groove.
(18) is depressed by δ ₁ , and furthermore, a pin guide at the front of the nose portion (11a)
The upper and lower portions of (21) are in front of the pin guide (21).
A print head having the same surface .