JPH057184B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a method for manufacturing a print head for a printing device that performs printing by striking a recording medium.

(b) Technical Background Figure 1 is an overall conceptual diagram of a serial printer. A frame 1 rotatably supports a platen 2 with its longitudinal direction as an axis, and is intermittently rotated via a gear 3 by a motor (not shown). The paper 4 is attached to sprockets 5a and 5 provided at both ends of the platen 2.
b and is sent by the rotation of the platen 2. The carrier 6 is guided by a rotating feed screw 8 via a belt 10 from a guide shaft 7 and a space motor 9, and moves in the direction of arrow A along the platen 2. The printing head 11 is mounted on the carrier 6, and is provided with a plurality of printing wires and an electromagnetic mechanism for driving them.The electromagnetic mechanism is selectively driven in synchronization with the movement of the carrier 6. The ink ribbon 13 is housed in the ink ribbon cassette 12 and runs between the print head 11 and the paper 4.

FIG. 2 is a side sectional view of print head 11 in FIG. An electromagnet formed by a coil-excited core 21 and a permanent magnet 20 are provided in the same magnetic path. Within this magnetic path, one end of an armature 25 to which a printing wire 26 is fixed is held via a spacer 23 so as to form a cantilever beam. The armature 25 is normally attracted to the core 21 by being bent by the gap G created by the spacer 23 by the magnetic attraction force of the permanent magnet 20. At the time of printing, the coil 22 is energized to cut off the attractive force of the permanent magnet 20, and the armature 25 is separated from the core 21 by the elastic force caused by the bending. With this operation, print wire 2
6 rapidly approaches the platen 2 and hits the platen 2 via the ink ribbon 13 and the paper 4. When the ink from the ink ribbon 13 adheres to the paper 4, printing is performed.

Next, when the coil 22 is de-energized, the free end is pulled into the core 2 again by the magnetic attraction force of the permanent magnet 20.
The printing wire 26 attracted to the wire 1 returns to its original position.

In such a print head, in order to maintain a constant print quality, it is necessary to make the impact force of each print wire 26 on the platen 2 constant when the armature 25 is released from suction.

Here, what has the greatest influence on the impact force is the magnetic attraction force of the permanent magnet, but this magnetic attraction force is greatly influenced by the magnetic resistance due to the air gap between each armature and the core.

Therefore, it is necessary to assemble the air gaps between each armature and the core to be all the same.

(c) Prior art and problems However, the print head as shown in Fig. 2 has individual parts (electromagnetic mechanism, armature,
Permanent magnets, etc.) are manufactured separately and then assembled by screwing them together using screws 24.
The distance between each of the plurality of armatures and the core provided opposite to this armature is not the same,
This has the disadvantage that the striking force of the printing wire varies, resulting in deterioration of printing quality.

In other words, since each part is manufactured separately, errors occur during the manufacturing of each part, and when assembling the parts where this manufacturing error has occurred, there may be errors between the parts (for example, the core and the armature). Errors occur.

Therefore, in the past, in order to prevent deterioration of printing quality (variations in the striking force of the printing wire), each part was finished with high precision to avoid assembly errors, and the printing head was extremely expensive. It's summery.

FIG. 3 is a diagram showing a state in which the armature 25 and the core 21 are attracted to each other in a printing head having the above-described drawbacks.

As shown in the figure, the armature 25 is attracted to the core 21, but when the armature 25 and the core 21 come into contact at the dotted circle indicated by symbol a in the figure,
If the spring constant of the armature 25 spring part (reverse concave part of the armature 25 indicated by symbol c in the figure) is stiff, an air gap remains in the dotted line circle indicated by symbol a' in the figure, and the magnetic resistance at this part increases. Since it is large, the suction force of the armature 25 is weakened, and when the suction is released, the striking force of the print wire 26 against the platen 2 is weakened, which has the disadvantage of deteriorating print quality.

For this reason, conventionally, the surface of the armature that faces the core is shaved diagonally so that the armature and the core come into contact when the armature and the core are attracted to each other. FIGS. 9 and 10 are diagrams for explaining a conventional cutting method for the lower end surface of an armature. FIG. 9 is a front view, and FIG. 10 is a side sectional view. In the figure, 26 is a printing wire, 27
28 is a plate spring to which the armature 29 is fixed; and 51 is a jig for holding the plate spring 28 and the like for cutting the lower end surface of the armature. Reference numeral 52 is a load meter, which is used to determine how much load is being applied when the mounting member 27 is pressed down by a pin 53 provided at its tip by reading a scale G. Reference numeral 54 is a case that is provided in the load cell mounting portion 51b of the jig 51 and holds the load cell 52 so as to be slidable in the direction of the arrow shown by symbol F in the figure, and 55 and 56 are bolts that sandwich the mounting member. Positioning is performed by

The operation of the configuration shown in the figure will be explained.

First, the mounting member 27 to which the printing wire 26 is attached is fixed to the armature 29, and the armature 29 is attached to the leaf spring 28. The leaf spring assembly 57 constructed in this manner is fixed to the leaf spring mounting diagram 51a of the jig 51 with screws 58.

In this state, the mounting member 27 is pressed down by the pin 53 at the tip of the load cell 52. Then, while reading the scale G, when the load reaches 500 g, for example, the printing wire 26 (or the armature 29) is pressed down by a predetermined stroke amount (the displacement of the leaf spring 28 with respect to the load is linear). Therefore, in order to maintain this state, the mounting member 27 is sandwiched and fixed with bolts 55 and 56.

Therefore, at this time, the lower end surface 2 of the armature 29
9a is removed by a predetermined amount protruding from the lower end surface 51c of the jig 51.

After polishing the lower end surface of the armature 29, loosen the bolts 55, 56 and remove the screw 58.
Remove the leaf spring assembly 57 from the jig 51.

By sequentially repeating the steps described above, the lower end surfaces of the plural armatures 29 are scraped off. Then, as shown in FIG.
Attach to.

As explained above, the lower end surface of the armature 29 is scraped off, but since the leaf spring assemblies 57 are mounted one by one on the jig 51 and the scraping work is performed, it takes time to prepare for the scraping work. There is a drawback. Further, 1 of the leaf spring assembly 57
Since the pressed position is fixed by the bolts 55 and 56 after being pressed down with a predetermined load, it is difficult to automate it, and there is a drawback that everything is done manually. In addition, since the plate spring assemblies 57 that have been scraped off are attached to the electromagnet mechanism 46 one at a time, installation errors occur due to manufacturing errors, etc., and a difference occurs in the driving force of each printing wire, making it difficult to perform the desired printing. The disadvantage is that it cannot be done. Furthermore, in order to reduce the difference, each part must be finished with high precision, which results in an expensive printing head.

Furthermore, with a plurality of leaf spring assemblies 57 attached to one jig, each leaf spring assembly 57 may be attached to the electromagnet mechanism 46 after the lower end surface of the armature is scraped off by batch polishing. Although this is possible, there is a drawback that differences occur between each armature after installation due to plug image errors of other parts.

(d) Purpose of the invention In view of the above-mentioned conventional drawbacks, the purpose of the present invention is to
The surface facing the core of the amateur can be easily and inexpensively cut by using a simple jig and a simple method to push down the amateur to the adsorption position to the core. An object of the present invention is to realize a method of manufacturing a print head that can prevent differences in driving force between the print heads.

(e) Structure of the Invention The object of the invention is to have a plurality of cores constituting an electromagnetic mechanism attached to a first base, and a plurality of armatures each having a printing wire attached to each of the cores attached to a second base. A method for manufacturing a print head, wherein the print head is configured by fixing the first and second bases so that the cores and the armatures face each other, the plurality of After attaching the armature to the second base, align the printing wires protruding from the tip of the printing head to a predetermined length from the tip of the printing head, and then press the tips of all the printing wires at the same time with the pressing member. the plurality of armatures are polished at once so that they are on the same surface, and then the second base is fixed to the first base to which the plurality of cores are attached. This is achieved by providing a method of manufacturing a printhead.

(f) Embodiments of the Invention Examples of the method for manufacturing a printing head according to the present invention will be described in detail below with reference to the drawings.

FIGS. 4 and 5 are diagrams for explaining one embodiment of the method for manufacturing a print head according to the present invention.

In the figure, 26 is a printing wire, 27 is a mounting member to which one end of the printing wire 26 is fixed, 28 is an armature to which the mounting member 27 is fixed, and 29 is a leaf spring to which the armature 28 is fixed, and the upper and lower parts are A plurality of them are provided so as to be sandwiched between the two annular members 30 and 31 and to be directed toward the center from the annular members 30 and 31.

The annular members 30 and 31 are fixed to a second mount 32, which is a second base, with a plurality of screws 33.

Reference numeral 34 denotes a jig, on the top of which is a screw 35 having a pressing member 36 for simultaneously pressing down the printing wire at its tip, and a support member 40 for supporting guide members 38 and 39 for guiding the printing wire 26. It is provided with screws 41 and 42 for fixing.

In the configuration described above, first, the leaf spring 29 to which the mounting member 27 and the armature 28 are attached is fixed to the second mounting base 32 with screws 33.

At that time, the printing wire 26 is connected to the guide members 38, 3
9 and is passed through a pin hole (not shown) provided in the head tip 37.

Furthermore, the print wire 26 is connected to the head tip 37.
The printing wire 26 is cut to a predetermined size so that the amount of the printing wire 26 protruding from the tip end surface 37a is slightly longer than the printing stroke, and is attached to the mounting member 27. Thereafter, after the plate spring 29 is fixed to the second mounting base 32, the printing wire 26 is polished so that its tip end has a predetermined length from the tip end surface 37a.

Next, the jig 34 is attached to a support member 4 as shown in FIG.
0, then screws 41 and 42
Fix it by.

Thereafter, by tightening the screw 35, the pressing member 36 is brought into contact with all the tips of the print wires 26 concentrated on the tip surface 37a of the print head tip 37 at the same time. At this time, the screw 35 is provided so that when the screw 35 is screwed all the way into the jig 34, the pressing member 36 just contacts the tip of the printing wire 26.

In this state, the armature 28 is placed on a polishing plate, and the lower end surface of the armature 28 is ground using, for example, the lower end surface 30a of the annular member 30 as a reference surface.

When cutting of the lower end surface of the armature 28 is completed, the jig 34 is removed from the support member 40 by loosening the screws 41 and 42.

Then, as shown in FIG. 5, the second mounting base 32 is attached to an electromagnet mechanism 46 consisting of a permanent magnet 44, a core 21, a coil 45, etc. via a spacer 50.

At this time, in FIG. 4, the annular members 30, 31
Screw 3 for fixing to the second mounting base 32
3 is changed to a long one, and is attached by passing through the permanent magnet 44 and further passing through the first attachment part 47 of the electromagnet mechanism 46, which is the first base.

FIGS. 6 and 7 are diagrams for explaining a second embodiment of the method of manufacturing a print head according to the present invention. In the figure, 26 is a printing wire, 27 is a mounting member to which one end of the printing wire 26 is fixed, 28 is an armature to which the mounting member 27 is fixed, and 29 is a leaf spring to which the armature 28 is fixed, and the upper and lower parts are Two annular members 30, 3
A plurality of them are provided so as to be sandwiched between the members 30 and 31 and to be directed toward the center from the members 30 and 31.

The annular members 30 and 31 are fixed to a second mount 32, which is a second base, with a plurality of screws 33.

Reference numeral 34 denotes a jig, and on its upper part there is a pressing member 36 that simultaneously presses down the printing wire 26 at its tip.
and screws 41 and 42 for fixing the portions of the support member 40 that support the guide members 38 and 39 that guide the printing wire 26.

In the configuration described above, first, the leaf spring 29 to which the mounting member 27 and the armature 28 are attached is fixed to the second mounting base 32 with screws 33.

At that time, the printing wire 26 is connected to the guide members 38, 3
9 and is passed through a pin hole (not shown) provided in the head tip 37.

Furthermore, the print wire 26 is connected to the head tip 37.
The printing wire 26 is cut to a predetermined size so that the amount of the printing wire 26 protruding from the tip end surface 37a is slightly longer than the printing stroke, and is attached to the mounting member 27. Thereafter, after the plate spring 29 is fixed to the second mounting base 32, the printing wire 26 is polished so that its tip end has a predetermined length from the tip end surface 37a.

Next, the jig 34 is attached to a support member 4 as shown in FIG.
0, then screws 41 and 42
Fix it by.

Thereafter, by tightening the screw 60, the pressing member 36 is pressed against the tip surface 37a, and all of the plurality of printing wires 26 are simultaneously sucked (sixth
Position it so that it is in the condition shown in the figure).

In this state, it is placed on a polishing plate and, for example, the dotted line portion 43 of the lower end surface of the armature 28 is scraped off using the lower end surface 30a of the annular member 30 as a reference plane. By scraping off the lower end surface 30a of the annular member 30 together with the armature 28, the lower end surfaces of the annular member 30 and the armature 28 are made to be on the same plane in the non-printing state. In addition, at this time, the annular member 30 is naturally set to a dimension including a machining allowance so that it will have a predetermined dimension after cutting is completed. After finishing cutting the lower end surface of the armature 28, screw the screws 41 and 4.
2 and 60, the jig 34 is removed from the support member 40.

Then, as shown in FIG. 7, the second mounting base 32 is attached to an electromagnet mechanism 46 consisting of a permanent magnet 44, a core 21, a coil 45, and the like.

At this time, in FIG. 6, the annular members 30, 31
Screw 3 for fixing to the second mounting base 32
3 is changed to a long one, and is attached by passing through the permanent magnet 44 and then passing through the spacer 50 to the first attachment part 47 of the electromagnet mechanism 46, which is the first base. This spacer 50 is
If the armature 28 is cut too much due to parts installation errors, etc., the part of the armature 28 shown by symbol E in the figure may hit first during suction, and it may not be possible to obtain the desired suction force, so this is provided to correct this. ing. Therefore, although the armature 28 and the core do not necessarily come into contact with each other, there is no particular problem in practical use. Further, when cutting the lower end surfaces of the armature 28 and the annular member 30 described above, if a member such as the second mounting base 32 is placed in an inclined state with respect to the polishing plate, the annular shape When the member 30 is attached to the electromagnet mechanism, the printing wire 26 is attached at an angle, so it is also used to correct this. Note that there is almost no need for correction in practice.

Furthermore, in the above description, it is assumed that both the armature 28 and the annular member 30 are shaved, but it is also used to correct a case where, for example, only the armature is shaved in an inclined state.

When polishing the armature 28, use the jig 3.
4 is held by a chuck of a machine tool, placed on a polishing disk, and then cut to a reference surface, which can be easily automated. Further, automation can be further facilitated by using a hand such as a robot that has a gripping mechanism for gripping the support member 40 or the second mounting base 32 and a function for pressing down the printing wire 26.

FIG. 8 is an F-S curve diagram showing the relationship between the attractive force F of the permanent magnet 44 and the stroke amount S of the printing wire 26 before and after polishing the armature.

In the figure, the horizontal axis represents the stroke S of the printing wire 26 (in mm), and the vertical axis represents the attractive force of the permanent magnet 44 and the restoring force F of the leaf spring 29 (in g). Also, after the solid line a polishes the amateur 28,
The dotted line b shows the characteristics before polishing.

As shown in the figure, compared to before polishing the armature 28, the printing stroke amount is
The increase is due to the removal of the lower end of 8. Furthermore, the amateur attractive force of the permanent magnet 44 is increased without changing the magnetic force and magnetic path of the permanent magnet 44.

Therefore, the energy accumulated in the leaf spring 29 can be increased, and the printing energy can be increased.

Furthermore, the holding force of the armature 28 becomes sufficiently larger after polishing (ΔF ₂ ) than before polishing (ΔF ₁ ), and the operation of the armature 28 becomes stable.

(g) Effects of the Invention As explained above, in the present invention, it is only necessary to polish the armature after pressing down all of the plurality of printing wires by the printing stroke amount, so that the wires simply protrude from the tip of the head. All you need is a jig with a member that presses down the printing wire, and since the printing wire is concentrated at the tip of the printing head, only one pressing member is required for multiple armatures, and its size is small. That's fine. Therefore, the polishing jig has an extremely simple structure, and the printing head can be manufactured simply and at low cost.

[Brief explanation of the drawing]

Fig. 1 is an overall schematic diagram of a serial printer, Fig. 2 is a side sectional view of the print head, Fig. 3 is a diagram of the adsorption state of the armature and core in a conventional print head, and Figs. 4 and 5 are 6 and 7 are diagrams for explaining the method for manufacturing the print head according to the second embodiment, and FIG. 8 is a diagram for explaining the method for manufacturing the print head according to the second embodiment. F shows the relationship between the attraction force F of the magnet and the stroke S of the printing wire
-S curve diagrams, FIGS. 9 and 10 are diagrams for explaining a conventional method of cutting the lower end surface of an armature. In the figure, 26 is a printing wire, 28 is an armature, 29 is a leaf spring, 30 and 31 are annular members, 3
2 is a second mounting base (second base), 47 is a first mounting base (first base), 34 is a jig, 3
5, 41, 42, and 60 are screws, and 36 is a pressing member.

Claims (1)

[Claims] 1. A plurality of cores constituting an electromagnet mechanism are attached to a first base, and a plurality of armatures to which printing wires are attached can be arranged on a second base facing each of the cores. attached to the first and second
A method of manufacturing a print head, comprising: fixing a base such that each core and each armature face each other to form a print head, the plurality of armatures having an elastic body attached to the second base; The printing wires protruding from the tip of the printing head are aligned at a predetermined length from the tip of the printing head, and all the tips of the printing wires are pressed down simultaneously by a pressing member, When each armature is attracted to the core, the elastic body is bent in advance so that the surface of each armature facing the core becomes the same surface, and a plurality of armatures are placed in an adsorbed state. The second base to which the plurality of armatures are attached is then fixed to the first base to which the plurality of cores are attached. A method of manufacturing a printing head.