JPH0445890Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a printing head, and more particularly to a structure of a plurality of wire tips.

[Prior Art] In a printer with a print head facing a cylindrical platen, when the end surfaces of the tips of a plurality of wires are arranged on the same plane, the wires facing the center of the platen and the wires facing the center of the platen Since the stroke of the wire is different from the wire away from the
Dot unevenness occurs.

Therefore, conventionally, as shown in FIG. 3, the end surfaces of the tips of the plurality of wires 1 are polished into circular arcs along the surface 3 of the platen 2. Note that this type of printing head is disclosed in Japanese Patent Application Laid-open No. 57-173178 and Japanese Patent Application Laid-open No. 59-1989.
-199264 publication and Japanese Patent Application Laid-Open No. 60-228025 are known.

[Problems to be Solved by the Invention] The conventional example described above has a problem in that the processing cost is high because the polishing is performed in an arc shape. In addition, in the case of a wire-separated type in which the wire and the armature that drives the wire are constructed separately,
Since the wire rotates, if the wire 1 rotates as shown by the dotted line 4 in Figure 3, the angle with respect to the platen 2 will become larger, making the pixels unstable when printing and causing problems such as ribbon catching. It becomes more likely to occur.

It is an object of the present invention to provide a printing head which can reduce processing costs and which can be used without problems regardless of whether the wire and armature are formed separately or integrally.

[Means for Solving the Problems] The problem with the above-mentioned conventional technology is that a plurality of wires each having a tip end face perpendicular to the wire axis are divided into a plurality of wire groups having different lengths, and the tip end face of the wires is The problem is solved by arranging the plurality of wire groups in a stepped manner so that the wires approximately follow the surface of the cylindrical platen, and the number of wires in the center wire group is greater than the number of wires in the outer wire group. be done.

[Example] An example of the present invention will be described below with reference to FIGS. 1 and 2. Print head nose (not shown)
On the tip guide plate 5 attached to the tip of the wire, the tips of a plurality of wires 6 are arranged in two rows in a staggered manner. The tip end face of the plurality of wires 6 is
The wires 6 are formed perpendicularly to the axis of the wire 6 and are arranged in a step-like manner so as to approximately follow the arc 7 on the surface of a cylindrical platen (not shown).

In this embodiment, the shortest wire group a located near the center of the platen, and the wire group a
wire group b, which has an intermediate length and is slightly longer than wire group a, adjacent to wire group a, and wire group c, which is the longest and is located near the position farthest from the center of the platen.
It is composed of different types of wires 6. For example, when the radius of the platen is 20 mm and the array length of the wires 6 is about 3 mm, the step s between wire group a and wire group b is about 30 μm, and the height difference between wire group a and wire group c is about 30 μm.
The step t between the two is also formed to be approximately 30 μm.

Therefore, wires 6 of different lengths (three types in the embodiment) with flat polished end faces are prepared in advance, and these wire groups a, b, and c are attached to the nose.

In this way, the end face of the tip end of the wire 6 can be polished by plane polishing, thereby reducing processing costs. Moreover, no problem will occur even if the wire 6 is used separately from the armature. Also wire 6
Since the end face of the tip end is arranged in a stepped manner to approximately follow the surface of the cylindrical platen, the stroke of all the wires 6 with respect to the platen is almost constant, and the response period is also almost constant. . Further, the wire 6 is divided into a plurality of wire groups a, b, and c, and the number of wires in the wire group a at the center is greater than the number of wires in the outer wire group c, so the number of wire types can be reduced, and It is possible to manufacture a large number of wire groups of standard length to be arranged in a section, and to reduce the number of wire groups of other different lengths, which is excellent in management man-hours, productivity, and ease of assembly.

[Effects of the invention] As is clear from the above explanation, according to the invention, processing costs can be reduced, and the wire and armature can be used without problems regardless of whether they are separated or integrally formed. It also has excellent management man-hours, productivity, and ease of assembly.

[Brief explanation of the drawing]

Figure 1 is a front view showing one embodiment of the present invention;
The figure is a sectional view taken along the line A--A in FIG. 1, and FIG. 3 is an explanatory side view of the conventional example. 6... Wire, 7... Arc on the surface of the platen,
a, b, c... wire group, s, t... level difference.

Claims (1)

[Scope of utility model registration request] A plurality of wires each having a tip end face perpendicular to the wire axis are divided into a plurality of wire groups having different lengths, and the plurality of wires are arranged so that the end face of the wires approximately follows the surface of a cylindrical platen. A printing head characterized in that the wire groups are arranged in a stepped manner, and the number of wires in the center wire group is greater than the number of wires in the outer wire group.