JP3655075B2 - Wire dot print head and method of assembling the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a wire dot print head in a serial printer, and more particularly to a wire dot print head in which printing mechanisms are stacked in two stages and an assembling method thereof.
[0002]
[Prior art]
Conventionally, various types such as a plunger type, a spring charge type, a clapper type, and a piezoelectric element type have been provided as wire dot print heads that perform printing by driving a printing wire. Among these, in the spring charge type print head, the armature to which the printing wire is fixed is supported swingably by a bias plate spring, and this armature is previously attracted to the core by a permanent magnet against the elastic force of the bias plate spring. Let me. When printing is performed, the coil wound around the core is excited to generate a magnetic flux in the direction opposite to the magnetic flux of the permanent magnet, thereby releasing the armature from the core.
[0003]
With respect to such a wire dot print head, with the recent increase in the amount of information, there is an increasing demand for high-speed printing. To increase the print head speed, the natural frequency of the armature should be increased. However, the increase in the natural frequency of the armature depends largely on the weight reduction of the armature, and after satisfying conditions such as reliability, rigidity, and potential. There is a limit to the weight reduction. Therefore, another method for speeding up is to increase the number of printing elements (armatures).
[0004]
In the current serial dot print head, a so-called 24-pin head in which 24 print elements are arranged in a substantially circumferential manner is the mainstream, but by using a 48-pin head in which the number of print elements is doubled, dots in the same line can be obtained. The two printing elements can be used, and even if the printing elements have the same natural frequency, the printing speed of the printing head is twice that of the 24-pin head. Although it is theoretically possible to increase the number of printing elements on the same plane, it is difficult to mount printing elements (armature, core, coil, etc.) due to restrictions on the outer shape of the print head. Therefore, a print head in which the number of print elements is increased by stacking print elements in two stages is becoming mainstream. By increasing the number of printing elements, not only high speed but also high density printing becomes possible.
[0005]
[Problems to be solved by the invention]
In a print head in which print elements are stacked in two stages, a lower print wire and an upper print wire are positioned by a common wire guide at the tip of the print head. However, since the lower printing wire has a long length to the print head tip, there is a problem that the position of the print wire tip varies and it is difficult to correctly insert it into a predetermined hole of the common wire guide. Even if a dedicated jig is used, the upper printing wire cannot be used because it gets in the way.
[0006]
In order to solve this problem, a method of enlarging the wire insertion hole of the common wire guide with a clearance with respect to the thickness of the printing wire can be considered. It becomes difficult to insert the printing wire into the printing wire, and a new problem arises that the vibration of the printing wire due to the enlarged insertion hole is not suppressed.
[0007]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention has two layers of printing mechanisms that perform printing by driving an armature having a printing wire fixed to the tip, and the printing wire of the lower printing mechanism is used as the printing wire of the upper printing mechanism. in the wire dot print head which is disposed inwardly, while located inside space of the printing wire of the upper printing mechanism, a common guide for both guiding the printing wires of the printing wire and the lower printing mechanism of the upper printing mechanism Ri a lower printing mechanism side is disposed so as to contact the common guide has a plurality of holes printing wires are arranged in substantially annular to be inserted in the lower printing mechanism, the hole is a common guide JP that printing wire is provided about the same is formed in a size Rutotomoni common guide substantially coincides with the guide member formed with an array spacing of holes printing wire is inserted in the hole to be inserted To.
[0008]
According to the present invention having the above-described configuration, the leading end portion of the lower printing wire is guided to a predetermined position by the guide member, and the lower printing wire can be easily inserted into the common wire guide.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the element common to each drawing. FIG. 1 is a sectional view showing a print head according to a first embodiment of the present invention.
[0010]
In FIG. 1, a wire dot print head 1 according to the first embodiment includes an upper printing mechanism 2 and a lower printing mechanism 3 that are stacked in two stages. In the upper printing mechanism 2, the printing wire 4 is fixed to the leading end of the armature 5, protrudes from the leading end of the printing head 1, and prints on a printing medium via an ink ribbon (not shown). The armature 5 is fixed to the free end of the leaf spring 6. A yoke 7, a permanent magnet 8, a yoke 9, and a connecting base 10 are arranged in this order below the fixed end of the leaf spring 6, and a base yoke 11 is arranged inside the connecting base 10.
[0011]
A core 12 is fixed to the base yoke 11, and a rotation fulcrum member 13 is disposed inside thereof. A coil 14 is wound around the core 12, and the coil 14 is connected to the substrate 15. The rotation fulcrum member 13 is a member that serves as a fulcrum for the armature 5 to rotate during printing. A substrate 15 is provided on the opposite side of the base yoke 11 via an insulating rubber packing 16 and a spacer 17.
[0012]
A yoke 18, a yoke 19, and a frame 20 are disposed in this order on the fixed end of the leaf spring 6. Wire guides 21, 22, and 23 are provided at the tip of the frame 20, respectively. These wire guides 21, 22, and 23 are common wire guides having holes into which both the printing wire 4 of the upper printing mechanism 2 and the printing wire 24 of the lower printing mechanism 3 are inserted. The upper printing mechanism 2 is configured as described above.
[0013]
The configuration of the lower printing mechanism 3 is almost the same as the configuration of the upper printing mechanism 2. Therefore, the same reference numerals as those of the elements of the upper printing mechanism 2 are attached to the elements of the lower printing mechanism 3 to replace the description. A frame 25 is provided on the upper portion of the lower printing mechanism 3 and wire guides 26 and 27 are fixed thereto. These wire guides 26 and 27 guide only the lower printing wire 24. An assembly wire guide 28 is provided below the common wire guide 23 (right side in the figure).
[0014]
FIG. 2 is a plan view showing the assembly wire guide 28. In FIG. 2, the assembly wire guide 28 has a substantially elliptical shape and is smaller than the range surrounded by the tip of each armature 5 of the upper printing mechanism 2. An insertion hole 29 is provided in the peripheral portion of the assembly wire guide 28. The insertion hole 29 is a hole into which the printing wire 24 of the lower printing mechanism 3 is inserted, and is printed by being inserted into the insertion hole 29. The tip of the wire 24 is positioned. The assembly wire guide 28 is made of a non-magnetic material.
[0015]
Next, the assembly procedure of the print head 1 according to the first embodiment will be further described with reference to FIGS. 3 to 6 are explanatory views showing the print head assembly procedure according to the first embodiment.
[0016]
In FIG. 3, the jig 31 is attached to the print head when the lower printing mechanism 3 is assembled. Two knock pins 32 are inserted into predetermined holes to fix the jig 31 to the print head. An arm 33 is rotatably attached to the jig 31, and a groove 34 for aligning the print wires is formed at the tip of the arm 33. When the jig 31 is fixed, the arm 33 is rotated to engage the arms 33 so that the printing wire 24 of the lower printing mechanism 3 is fitted into the groove 34. This state is shown in FIG. At this time, it is preferable to arrange a magnet around the groove 34 so that the printing wire 24 fits into the groove 34 properly.
[0017]
Here, the assembly wire guide 28 is fitted into the front end portion of the printing wire 24. This state is shown in FIGS. Next, the arm 33 of the jig 31 is rotated away from the printing wire 24 in the opposite direction, and the jig 31 is removed from the print head. When the arm 33 is rotated, the assembly wire guide 28 is moved away from the printing wire 24.
[0018]
Is the size of the hole 29 of the assembly wire guide 28 the same as the hole into which the printing wire 24 of the lower printing mechanism 3 of the common wire guide 23 that guides the printing wires 4 and 24 of the upper and lower printing mechanisms 2 and 3 is inserted? Or almost the same size. The assembly wire guide 28 is on the lower printing mechanism 3 side with respect to the common wire guide 23, and therefore the inclination of the printing wire 24 is large. Therefore, the hole 29 of the assembly wire guide 28 may be enlarged correspondingly.
[0019]
By fitting the assembly wire guide 28 into the printing wire 24, the leading end of the printing wire 24 is aligned as shown in FIG. 6, so that the printing wire 24 is easily inserted into the common wire guide 23. Since the tips of the printing wires 24 are aligned, the insertion hole of the common wire guide 23 does not need to have a large clearance from the printing wires 24, and the tips of the printing wires 24 inserted into the insertion holes of the common wire guide 23 are eliminated. The part is more accurately positioned with respect to the insertion hole of the next common wire guide 22. The same can be said for the next common wire guide 21.
[0020]
As described above, since the assembly wire guide 28 for inserting the printing wire 24 of the lower printing mechanism 3 is provided, the common wire guides 23, 22, 21 are moved to the stage before the upper and lower printing mechanisms 2, 3 are combined. The printing wire 24 can be easily inserted.
[0021]
Next, a second embodiment of the present invention will be described. FIG. 7 is a cross-sectional view showing a two-stage print head according to the second embodiment.
The assembly wire guide 28 of the first embodiment is thin on the outer side of the insertion hole 29, so that when the printing operation is performed to some extent, the outer part is worn and the printing wire 24 passes through the insertion hole 29. Come out. When the number of the printing wires 24 coming out of the insertion holes 29 increases, the assembly wire guide 28 moves in the vertical direction (the horizontal direction in FIG. 1), which can hinder the printing operation. The second embodiment solves this problem.
[0022]
In FIG. 7, the print head 40 according to the second embodiment is provided with a pressing member 41 between a wire guide 26 that guides the print wire 24 of the lower print mechanism 3 and an assembly wire guide 28. . The presser member 41 is mounted on the wire guide 26 inside the print wire 24 prior to mounting the assembly wire guide 28 before combining the upper print mechanism 2 and the lower print mechanism 3.
[0023]
As can be seen from the figure, the holding member 41 has a length corresponding to the distance between the wire guide 26 and the assembling wire guide 28. By providing such a holding member 41, the movement of the assembling wire guide 28 is prevented. can do. As the material of the pressing member 41, resin, felt or the like is used.
[0024]
In each of the above embodiments, the spring charge type print head has been described as an example of the print head. However, the present invention can be applied to other types of print heads such as a plunger type and a clapper type.
[0025]
【The invention's effect】
As described above in detail, according to the present invention, in the print head in which the print mechanisms are stacked in two stages, the assembly wire guide for positioning the lower print wire is provided, so that it is common with the upper print wire. This makes it easy to insert the lower printing wire into the wire guide.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a two-stage print head according to a first embodiment.
FIG. 2 is a plan view showing an assembly wire guide.
FIG. 3 is a perspective view showing a print head assembly procedure according to the first embodiment.
FIG. 4 is a perspective view illustrating a print head assembly procedure according to the first embodiment.
FIG. 5 is a perspective view illustrating a print head assembly procedure according to the first embodiment.
FIG. 6 is a perspective view illustrating a print head assembly procedure according to the first embodiment.
FIG. 7 is a cross-sectional view showing a two-step print head according to a second embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Print head 2 Upper printing mechanism 3 Lower printing mechanism 4, 24 Printing wire 21, 22, 23 Common wire guide 26 Wire guide 28 Assembly wire guide 41 Pressing member

Claims (3)

In a wire dot print head in which an armature having a printing wire fixed to the tip is driven to stack two layers of printing mechanisms, and the lower printing mechanism printing wire is disposed inside the upper printing mechanism printing wire. ,
With located inside space of the printing wire of the upper printing mechanism, the common guide a print wire and both guide common guide by Ri lower printing mechanism side printing wire of the lower printing mechanism of the upper printing mechanism It has a plurality of holes that are arranged so as to be in contact with each other and are arranged in a substantially annular shape into which the printing wire of the lower printing mechanism is inserted, and the holes are approximately the same size as the hole into which the printing wire of the common guide is inserted wire dot printing head, characterized in that formed Rutotomoni common guide print wire is provided substantially coincident with the guide member formed with an array spacing of the holes to be inserted into.   The wire dot print head according to claim 1, further comprising a position holding member that holds a position of the guide member. A wire dot printing head in which a printing mechanism that performs printing by driving an armature with a printing wire fixed to the tip is stacked in two stages, and the printing wire of the lower printing mechanism is disposed inside the printing wire of the upper printing mechanism. In the assembly method,
After assembling the lower printing mechanism, the assembly guide member is fitted to the tip of the printing wire of the lower printing mechanism,
Then combine the upper printing mechanism,
The assembly guide member is arranged by inserting the print wire of the lower print mechanism into the space inside the print wire of the upper print mechanism, and the assembly guide member is moved along the print wire of the lower print mechanism. Position the printing wire of the lower printing mechanism at a position that matches the hole of the common guide that guides each printing wire of the upper printing mechanism and the lower printing mechanism, and insert the common guide in the positioned state. An assembling method of a wire dot print head characterized by the above.

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