JP2881156B2 - Wire dot 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 print head.

[0002]

2. Description of the Related Art As conventional wire dot print heads, the following two types are widely known. Part 1
One type is a clapper type in which an armature (clapper) having a printing wire fixed to a leading end is driven by electromagnetic force to print on the paper at the leading end of the printing wire. As another one, the leaf spring is attracted by a permanent magnet, and the magnetic field of the permanent magnet is canceled by using the excitation of the magnet coil to release the leaf spring. This is a spring-charged type that prints by driving the printed wire. In either case, the print head is mounted on a carrier that moves in the printer case in a direction perpendicular to the paper feed direction.The number of print wires is the number corresponding to the number of dots in the column direction, or if parallel arrangement is used. It is provided with twice the number. Among these many printing wires, the printing wire which receives an operation signal sent from the control circuit of the printer main body operates and strikes the paper surface from above the ink ribbon to print on the recording paper.

[0003]

Since the wire dot print head in the prior art drives the armature by the same number as the number of dots to be printed, noise and heat generation increase as the number of dots printed per unit time increases. In addition, there is a limit to increasing the printing speed. Also, if the speed is increased by parallel arrangement while maintaining the print density in the column direction, the number of coils and iron cores for moving the print wires increases, so the weight of the print head increases, and the space inside the printer case increases. There is a problem such as having to increase the size.

It is therefore an object of the present invention to reduce the noise and heat generation of a wire dot print head, to reduce the weight and to increase the printing speed.

[0005]

In order to achieve the above object, a wire dot print head according to the present invention comprises a plurality of armatures operated by electromagnetic or piezoelectric elements and a print driven by each of these armatures. A wire dot printhead having a wire and
At the end of each armature, the rear end of the printing wire is arranged as a set of two wires, and the front end of the two printing wires in each set is moved in the row direction via a wire end guide. The wires are arranged so as to be adjacent to each other, and the tips of the wire pairs are aligned in the column direction.

[0006]

The armature corresponding to a pair of wire pairs forms two dots adjacent in the row direction by one operation, and the number of operations of the armature for forming dots in the row direction is the number of dots. Half of When the number of dots formed per unit time in the row direction is the same, the driving frequency of the armature and the coil for driving the armature can be halved. Conversely, when the driving frequency is the same, the number of dots formed per unit time in the row direction can be doubled. Furthermore, the number of armatures, the number of coils for driving the armature, and the like is reduced to half compared to the parallel arrangement in which the number of dots in the row direction is formed by two sets of armatures and the coils for driving the armature.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG . 1, an outer frame of a print head has a guide frame 2 attached to a front surface (left side) of a yoke frame 1 formed in a container shape, and a back side (right side) of the yoke frame 1. The opening is configured by covering the head cover 3.

[0008] A cylindrical guide portion 2a through which a plurality of printing wires are inserted is provided from the front center portion to the back surface of the guide frame 2, and a portion of the guide portion protruding from the back surface of the yoke frame 1 is a yoke frame 1. And protrudes inside the yoke frame through a through hole 1a provided in the center of the yoke frame.

A plurality of iron cores 4 formed integrally with the yoke frame 1 are radially arranged inside the back surface of the yoke frame 1. A coil 5 is wound around each iron core 4, respectively.
Excitation is possible by energizing the coil from the outside.

A support plate 6 formed by combining two support plates and a plate for adjusting the thickness is provided between an end surface 1b around the yoke frame 1 and an end surface 3a around the head cover 3. . An armature 7 is mounted between the support plates 6 in a state of being clamped. Armature 7
It is swingably mounted between support plates 6 via support pins 8. Each tip 7a of the armature 7 has 2
The rear end portion 9a of the set of print wire pairs 9 is fixed, and each print wire passes through the guide hole of the wire intermediate guide 10 provided in the guide portion 2a, and the front end portion 9b is the guide of the wire tip guide 11. It is inserted through the hole.

As shown in FIG. 2, the base 7b of the armature 7 is formed to have a large width so that the armature 7 can be attracted to the iron core 4. The lever 7c, which is substantially half of the armature 7, is formed in a thin plate shape. Thus, even when a large number of armatures are radially arranged in the yoke frame, the leading end 7a to which the printing wire is fixed can move forward and backward without touching the adjacent printing wire. In one set of print wire pairs 9, two print wires 91 and 92 are arranged adjacent to and parallel to the tip 7a of the armature 7, and are fixed by brazing.

As shown in FIG. 3, the wire intermediate guide 10
In the first embodiment, a plurality of guide holes 10a through which a pair of printing wires can be inserted adjacent to each other are arranged in two rows in an arc shape with a gentle curve. When the printing wires are fixed to the leading end of the armature 7 by the wire intermediate guide 10, the wire leading guides 1 are arranged in a circle.
In FIG. 1, it can be rearranged linearly.

Further, the guide hole 10a is provided with an armature.
At the tip of 7, aligned in the direction parallel to the axis of armature 7
Guide the two printing wires 91 and 92
11 also has the function of guiding in a line direction.
You.

As shown in FIG. 4, the wire tip guide 11
In this example, elliptical guide holes 11a into which a pair of adjacent wires 91 and 92 can be inserted are arranged in a straight line in two rows of 12 each. The tip of the printing wire 9 is the tip guide 1
Arranged with some side by side so as to be adjacent in the row direction becomes two pair by 1, each wire pair 91, 92 are aligned in two rows in the column direction via the guide holes but in two rows The two rows of wire columns thus arranged are arranged in a staggered manner so that the formation of dots in the column direction becomes dense.

As shown in FIG. 1, a pair of printing wires 9 fixed to a tip portion 7a of each armature 7 in a pair form a circular arc through a guide hole 10a (see FIG. 3) of a wire intermediate guide 10. , And further inserted into a guide hole 11a (see FIG. 4) of the distal end guide 11 so that the pair of two is adjacent to each other and the distal end portions 9b of the wire pairs 9 are aligned in the row direction. . A return spring holder 12 is provided at a position slightly away from the periphery of the guide portion 2a projecting from the center of the yoke frame 1 to the back of the yoke frame so as to surround the guide portion 2a. A spring 13 is attached. The distal end of the return spring 13 contacts the front side (left side in FIG. 1) of the lever 7c of the armature 7, so that the lever 7b of the armature can be urged backward. When no suction force acts on the armature 7 due to the iron core 4, the armature is retracted by this urging force, so that the leading end portion 9b of the printing wire can be retracted into the guide hole 11a of the wire tip guide. A stopper 14 for restricting the movement of the armature is provided inside the head cover 3 at a position facing the opposite side of the position where the return spring 13 contacts the armature 7 .

[0016]

[Operation] The print head of this embodiment is mounted on a printer, and a printing operation is performed while the print head is driven by a carrier (not shown). At this time, when a specific coil is energized in response to a signal from the control circuit of the printer, the iron core wound around the coil is excited, the armature 7 corresponding thereto is attracted, and the tip 7a is moved forward. Moving. Along with this, a pair of printing wire pairs 9 moves forward and strikes the printing surface to print. When the energization of the coil is stopped, the armature 7 returns to the original position by the return spring 13 and the stopper 1
4 and stops, and the leading end of the printing wire also retreats into the guide hole 11a of the wire leading end guide. In this operation, all the coils specified by the control circuit are operated at the same time, and each armature 7 is provided with a pair of printing wires 91 and 92, respectively. Of dots can be formed.

According to the print head of the present invention, for example, A,
When printing a character such as B, the dots formed by one of the wires 91 in the print wire pair are shown as black circles 91a in black, and the dots formed by the other print wire 92 are shown as white circles 92a in FIG. As shown in FIG. 7, dots are sequentially formed in the row direction with a pair of dots arranged in the row direction in the row direction, thereby forming a character composed of a group of a large number of dots. Since two dots are formed simultaneously in the row direction, it is possible to increase the feed speed in the row direction.

As shown in FIG . 6, when printing a horizontal line,
Is formed two dots at a time by the operation of one amateur 7.
When printing a vertical line, all the lines
-One line with a width of 2 dots due to the operation of the amateur
Is formed.

In this embodiment, a description has been given of an example in which the present invention is applied to a clapper type print head. However, the present invention is not limited to this, and can also be applied to a spring charge type wire dot print head. In this case, a similar effect can be obtained by arranging two print wires in parallel and driving them by a drive arm composed of one leaf spring. In addition, the present invention can also be applied to a piezoelectric wire dot print head in which a print wire is moved forward and backward by operation of a piezoelectric element. In this embodiment, a set of printing wires is fixedly arranged at the end of the armature. However, the armature is formed such that a lever portion is formed in a forked shape, and the printing wire is fixed to each end of the armature. It may be. Further, two armatures may be provided for one iron core. In addition, three or more printing wires can be provided as one set for one armature. Also, instead of fixing the wire to the armature tip,
The present invention is also applicable to a type in which the wire is separated and its rear end is hit with an armature tip.

The term "aligned in the column direction" as used in the present invention means that the tips of the printing wires are arranged at a predetermined pitch in the column direction. It also includes a rhombic arrangement.

[0021]

As described above, according to the present invention, two sets of printing wires are fixed to each armature in a set.
Since the tips are arranged adjacent to each other in the row direction via the wire tip guide, and the tips of each wire pair are arranged in the column direction, two operations of two dots are simultaneously made in the row direction by one operation of the armature. Forming becomes possible. Therefore, high-density printing can be performed in a short time. sand
KazuSatoshi, when the driving frequency is the same, can the number of dots formed per unit the row direction time doubled. Further, the number of armatures, the number of coils for driving the armature, and the like is reduced to half compared to the parallel arrangement in which the dots in the row direction are formed by two sets of armatures and the coils for driving the armature. Further, since the number of times of driving the armature requires only half,
Noise generation and heat generation are reduced accordingly, contributing to the improvement of the office environment. Furthermore, since requires only half the number of A Machua and coils enables weight reduction of the print head, the inertia force at the time of movement mounted on the carrier is also reduced, it is possible to correspondingly faster. In addition, since the number of iron cores and coils can be reduced, the number of parts and the number of assembling steps can be correspondingly reduced, and the cost can be reduced. In addition, if the printing speed is the same, it is possible to reduce the driving frequency of the armature, reduce noise, reduce heat generation, and reduce the precision of parts required for improved responsiveness, Cost reduction is achieved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is an enlarged front view showing a state in which a print wire is fixed to an armature.

FIG. 3 is a front view of a wire intermediate guide.

FIG. 4 is a front view of a wire tip guide.

FIG. 5 is an explanatory diagram showing an arrangement state of dots when characters A and B are printed.

FIG. 6 is an explanatory diagram showing an arrangement state of dots when a vertical line and a horizontal line are printed.

[Explanation of symbols]

 7 Armature 7a Armature Tip 9 Print Wire Pair 9a Rear End 9b Tip 11 Wire Tip Guide 91,92 Print Wire

Claims (2)

(57) [Claims] 1. A wire dot print head having a plurality of armatures actuated by electromagnetic or piezoelectric elements and a print wire driven by each armature, wherein each tip of said armature has
Wire dot printing head the rear end of the print wire is to arranged to said tare Rukoto a two by two as pairs. 2. The wire dot printing head according to claim 1,
In de, the tip of the printing wire of the two in the each set, characterized in that the tip of each wire pair are aligned in the column direction with some side by side so as to be adjacent in the row direction via a wire tip guide And a wire dot print head.