JPS6139561Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a dot printer head.

Generally, a flying dot printer is driven by an armature that is attracted by an electromagnet, and even when the armature stops, the needle flies out due to inertia and prints.The structure of a flying dot printer is as shown in Figures 1 and 2. . First, a mounting flange 3 having a mounting hole 2 for mounting on a carriage (not shown) is formed to extend from the base 1, and a support plate 4 is fixed to the center portion of the base 1. A guide body 6 is provided at the upper center of the support plate 4. The guide body 6 has grooves 5 radially formed on its outer periphery to guide dot pins, which will be described later. Next, a yoke 7 is attached on the base 1, and this yoke 7
A plurality of cores 8 are fixed to the core 8, and a coil 9 is wound around these cores 8 to form an electromagnet 10. Further, an armature 12 is provided on the upper edge of the yoke 7 and is hinged through a notch 11. This armature 12 faces the core 8 and has a tip 13 inserted into the groove 5. A tension spring 15 is provided at the end and tensioned between the pin 14 provided on the outer peripheral surface of the yoke 7.
is provided. The tip ends 13 of these armatures 12 are prevented from rotating upward by a stopper plate 17 fixed to the guide body 6 with a nut 16. Further, needles 18 are inserted into the groove 5, heads 19 are integrally formed at the tips of these needles 18, and a compression spring 20 is installed between the head 19 and the support plate 4. The head 19 is inserted into the armature 12 so that it is always urged to come into contact with the armature 12. The needles 18 are guided by a central guide piece 21 and a tip guide piece 22, and a plurality of needles 18 are arranged in a straight line at the tip guide piece 22.

Further, a PC board 23 extends from the base 11, and a lead wire 24 connected to an external circuit extends from the PC board 23. Furthermore, 25 is a cover that is joined to the periphery of the base 11 and covers the entire base. Note that 26 is a platen, 27 is printing paper, and 28 is a ribbon.

However, in the conventional type, the amount of bending of the plurality of needles 18 differs for each needle 18, resulting in unstable performance.

Therefore, a device in which the amount of bending of the needle 18 is made constant is disclosed in Japanese Patent Application Laid-Open No. 1820-1983. Armature 12 and needle 1 in this case
The arrangement relationship of the pressing rear end 29 of No. 8 is shown in FIG. In this figure, seven needles 18 are used. This is illustrated in a simplified diagram as shown in FIG. That is, in this means, the pressing rear end 29 of the needle 18 is arranged on a plane including the central axis 30 of the coil 9 and the tip 31 of the needle 18. For this reason, the distance between the pressing rear ends 29 of each needle 18 is different,
The bending amount h of the needle 18 is regulated by the minimum distance lmin between the pressing rear ends 29,
It cannot be lowered below a certain level. After all, if the length of the needle 18 is shortened, the frictional resistance will increase, the printing performance will deteriorate, and the durability of the needle 18, the center guide piece 21, the tip guide piece 22, etc. will deteriorate, and on the other hand, the length of the needle 18 Increasing the length of the needle 18 reduces frictional resistance, but increases the shape of the head and increases the weight of the needle 18, which affects durability and performance.

This idea was created in consideration of these points, and it minimizes the amount of bending of the needle to a constant value, reduces the frictional load acting on the needle, and has an electromagnetically and mechanically advantageous arrangement, which allows each needle to operate in a compact and high-performance manner. The object of this invention is to obtain a dot printer head that is uniform in condition.

This idea involves arranging the tips of multiple needles of the same length at equal pitches on a straight line, bending the needles by the same amount, and pressing the needles within a range that does not interfere with the armature that drives each needle. By placing the rear end close to the center and placing them at equal distances from each other, the amount of bending of each needle can be reduced, which reduces the frictional load acting on the needles and enables high-performance printing. In addition, since the electromagnets that drive the armature are set at equal distances from the pressing rear end of the needle, and the spacing between adjacent electromagnets is equal, the electromagnetic influence on each electromagnet is equalized, and the driving state of each needle is It is configured such that printing is performed substantially uniformly and good print quality can be maintained.

An embodiment of this invention will be explained based on FIGS. 5 to 7. Components that are the same as those shown in FIGS. 1 to 4 are designated by the same reference numerals, and description thereof will be omitted. First, the tips 31 are arranged linearly at equal pitches.
A book needle 18 is provided. All of these needles 18 have the same length and the same bending amount h, and their respective pressing rear ends 29 are radially distributed around the tip 31 when viewed in plan, and each pressing rear end 29 is equidistant from each other. It is arranged so that Then, the pressing rear ends 2 of these needles 18
The coils 9 are provided with equal distances H from the central axis 30 to the coils 9, and the intervals L between the coils 9 are equal.

Therefore, the tip of armature 12, needle 1
The distance between the pressing rear ends 29 of No. 8 is set to the minimum within a range where the pressing rear ends 29 etc. do not interfere with each other, that is,
If the pressing rear end 29 of the needle 18 is brought closer to the center within a range where the armature 12 does not interfere, the frictional force acting on the needle 18 will also be reduced and printing performance will be improved. Specifically, needle 18
The relationship between the length and the bending load W on the needle 18 is as follows: The bending amount h of the needle 18 is 2.4 mm, 2.0 mm, 1.6
When I measured it by changing it to mm, the result was as shown in Fig. 7.If the length of the needle 18 is the same, the smaller the bending amount h, the smaller the bending load W becomes, and the above-mentioned effect can be obtained. be. Also, coil 9
The equal spacing between them allows the head profile to be minimized, which is mechanically advantageous and reduces the inertia of the armature 12. Furthermore, since the coils 9 and the like are arranged at equal intervals, the electromagnetic influence becomes equal to each other, and as a result, the driving state of each electromagnet 10 becomes uniform, and each needle 18 is operated equally, thereby printing Improve quality.

As mentioned above, this idea involves arranging the tips of multiple needles of the same length at equal pitches on a straight line, bending these needles by the same amount of bending, and bending the needles within a range where the armatures that drive each needle do not interfere with each other. By placing the pressing rear ends of the needles close to the center and placing them at equal distances from each other, the amount of bending of each needle can be reduced, which reduces the frictional load acting on the needles, resulting in high-performance printing. In addition, since the electromagnets that drive the armature are equidistant from the pressing rear end of the needle and the spacing between adjacent electromagnets is equal, the electromagnetic influence on each electromagnet is equal, and each This has the effect that the driving state of the needles is approximately uniform, so that good printing quality can be maintained.

[Brief explanation of the drawing]

Figure 1 is a partially cutaway plan view showing the general structure, Figure 2 is a partially cutaway rear view, and Figure 3 is a partially cutaway plan view showing the general structure.
The figure is a schematic back view showing a conventional example, FIG. 4 is a schematic back view thereof, FIG. 5 is a schematic back view showing an embodiment of this invention, and FIG. 6 is a schematic back view thereof. FIG. 7 is a needle length-load characteristic diagram. 9... Coil, 10... Electromagnet, 12... Armature, 18... Needle, 29... Pressing rear end, 31... Tip.

Claims (1)

[Scope of utility model registration request] In a flying dot printer, a needle driven by an armature attracted by an electromagnet is provided, and even if the armature stops, the needle flies out due to inertia and prints. are arranged at equal pitches on a straight line, and these needles are curved by the same amount of bending, and the pressing rear ends of the needles are brought close to the center to the extent that the armature that drives each needle does not interfere with each other, and the needles are spaced at equal distances from each other. A dot printer head, characterized in that electromagnets for driving the armature are arranged at equal intervals between adjacent electromagnets at equal distances from the pressing rear end of the needle.