JPS5998854A - Multi-stylus head - Google Patents

Abstract

PURPOSE:To suppress the lowering in recording quality caused by the abrasion of a needle electrode even if recording is repeatedly performed, by bringing the contact part of the needle electrode to Vickers hardness of 100 or more to enhance the anit-wear property thereof. CONSTITUTION:The return electrode 3 and the contact part 12a of a plurality of needle electrode 12 embedded in an enclosing and embedding member 4 are exposed to the head contact surface 11a contacted with an ink ribbon. Each of these needle electrodes 12 has a wire diameter (d) of 60mum and formed of stainless steel having Vickers hardness of 300-500 and they are arrnaged in a zigzag pattern at such intervals that the distance l1 between the electrodes is 65mum while return electrodes 3 each having the large contact area with the ink ribbon are arranged to both sides of said needle electrodes 12 so as to leave a space-apart distance l2 of 400mum from each side of said electrodes 12. In this case, said needle electrodes 12 and the return electrodes 13 are embedded in the enclosing and embedding member 4 consisting of epoxy resin, a curing agent and a SiC powder.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention is a multi-function printer used in recording devices such as facsimiles and word processors. , relates to a stylus head, and more specifically relates to a multi-stylus head used in a single current transfer recording method.

Problem 1 - Conventional multi-stylus heads of this type include those shown in FIGS. 1 and 2, for example. That is, this multi-stylus head 1 is formed into a long plate shape with a large number of needle electrodes 2 and return electrodes 3 made of copper wire embedded in an embedding member 4 made of an insulating resin. The needle electrodes 2 are arranged in two rows 4'L in a staggered manner, and return electrodes 3 are spaced apart from each other on both sides of these needle electrodes 2. The contact portion 2a of the needle electrode 2 and the return electrode 3 are exposed from the head contact surface 1a.

Such a multi-stylus head 1 is arranged, for example, as shown in FIG. 1, as a part of a recording apparatus using an electric transfer recording method. Specifically, the multi-stylus head 1 and the roller 5 are arranged with a slight distance between them, and the ink ribbon 6 and the recording paper 7 are placed in this gap.
is interposed with the ink ribbon 6 in contact with the contact portion 2a of the needle electrode 2 and the return electrode 3. Note that the reference numeral 8°9 is a roller that moves the ink ribbon 6 and the recording paper 7.

Here, the current transfer recording method will be explained with reference to FIG. First, when a pulsed voltage, that is, a signal voltage is applied to the multi-stylus head 1, a pulsed current flows between the needle electrode 2 and the return electrode 3 via the ink ribbon 6.

At this time, since the area of the contact portion 2a of the sword-shaped electrode 2 is very small compared to the area of the return path electrode 4, the resistance is overwhelmingly larger under the needle-shaped electrode 2, and the current is Since the areas under the needle electrode 2 and the return electrode 3 are the same, most of the Joule heat generated by the current flowing through the system is generated under the needle electrode 2. This heat generation melts the ink ribbon 6 under the needle electrode 2, and the ink is transferred to the recording paper 7 in a dot shape and fixed. This is the case when the needle electrode 2
This is done when the contact portion 2a slides on the ink ribbon 6, and characters, etc. are drawn on the recording paper 7.

However, since the current transfer recording method requires that the contact portion 2a of the needle electrode 2 and the ink ribbon 6 come into contact with each other, the needle electrode 2 is formed of copper wire with a Vickers hardness of 60 to 100 as in the past. As the ink ribbon is used repeatedly, it gradually wears out and the electrical contact with the ink ribbon 6 deteriorates, which may cause deterioration in recording quality such as a decrease in dot density and the occurrence of missing dots. Ta.

The present invention has been made in view of the above-mentioned conventional situation, and at least the contact portion of the needle electrode has a Vickers hardness of 10.
The object of the present invention is to provide a multi-stylus head in which the wear resistance is improved by setting the number to 0 or more, and the deterioration in recording quality due to wear of the needle electrode is suppressed as much as possible even when recording is performed repeatedly.

The present invention will be explained below based on the drawings. In this description, redundant description of parts or members that are the same or equivalent to those of the prior art will be omitted.

FIG. 4 is a diagram showing a first embodiment of the present invention.

First, to explain the configuration, FIG. 4 shows a head contact surface 11a that contacts the ink ribbon 6 of the multi-stylus head 11.
, and on this surface 11a are the return electrode 3 embedded in the embedding member 4 and the contact portions 1 of the numerous needle electrodes 12.
2a is exposed. More specifically, this needle electrode 12
has a wire diameter d of 60μ and a Vickers hardness of 300 to 500.
It is made of stainless steel, and the inter-electrode distance Q1 is 65
These needle-like electrodes 1 are arranged in a staggered manner at intervals of μ.
Return electrodes 3 having a large contact area with the ink ribbon 6 are disposed on both sides of the ink ribbon 6 at a distance Q2 of 400 μm. These needle electrodes 12 and return electrodes 3 are embedded in an embedding member 4 made of epoxy resin, curing agent, and SiC powder.

Next, the effect will be explained. When a signal voltage is applied to the multi-stylus head 11 to perform current transfer recording, a pulsed current flows between the needle-shaped electrode 12 and the return path electrode 3, generating Joule heat under the needle-shaped electrode 12, and the ink ribbon is heated. The ink No. 6 is melted, transferred, and fixed onto the recording paper 7. At this time, the contact portion 12a of the needle-like electrode 12 slides on the ink ribbon 6, but since the needle-like electrode 12 is made of a hard material, the amount of wear is small even when recording is repeated. This results in a decrease in dot density and a delay in the occurrence of dot removal, and the durability of the multi-stylus head 11 is improved. To show this concretely in comparison with the conventional method,
Conventionally, when using a needle-shaped electrode 2 made of copper wire with a Vickers hardness of 8o, the number of durable characters is 5'x10', whereas when using the sword-shaped electrode 12 of this embodiment, the number of durable characters is 5'x10'. 2. It becomes clear that the durability is improved. Now, as for the return electrode 3, it has a large contact area with the ink ribbon 6, so even if it wears out a little, it will not become impossible to contact, and since it does not melt the ink under the return electrode 3, In this case, reliable contact is not required, and wear of the return electrode 3 is not so problematic.

Although the needle electrode 12 in the above embodiment is made of stainless steel, it may of course be made of nickel having a Vickers hardness of 150 to 200, iron having a Vickers hardness of 200 to 300, or the like.

Further, FIG. 5 shows a second embodiment.

In this embodiment, the sword-shaped electrode 22 of the multi-stylus head 21 consists of a contact portion 22a and a buried portion 22b, and only the contact portion 22a is formed to have a Vickers hardness of 100 or more. That is, the embedded part 22b embedded in the embedded member 4 of the needle electrode 22 is made of a copper wire with a wire diameter of 45μ and a Vickers hardness of 80, for example, and protrudes from the head contact surface 21a of the multi-stylus head 21 by about 10μ. The contact portion 22a is made of NiP alloy (with a Vickers hardness of 550).
92% Ni, 8% P) is formed by plating the buried portion 22b.

To explain this molding method, first, the buried portion 22b of the needle electrode 22 and the return electrode 3 are buried in the embedding member 4, and then cut and polished to form the head contact surface 21 into a flat surface. The shape in this state is the same as that of the first embodiment and the conventional example. After that, the return electrode 3 was masked with tape and coated with Ni; 92%.

When immersed for 2 hours in an electroless plating solution at 80°C containing 8% P (diaric acid, Nippon Kanigen's trade name Shuma BO1 nickel chloride, etc.), NiP with a Vickers hardness of 550 is formed.
An alloy is deposited to a thickness of 10 μm on the end face of the buried portion 22b to form a hard contact portion 22a protruding from the head contact surface 21a.

As a result, the hardness of the contact portion 22a of this embodiment is made even greater than that of the contact portion 12a of the first embodiment, and the wear resistance is further improved, the durability of the multi-stylus head 21 is further improved, and recording quality is improved. The time of occurrence of deterioration can be further delayed. If this is expressed by the number of durable characters as mentioned above,
In contrast to 2×10 in the first embodiment, this embodiment has lXlO7
It is clear that the durability is improved. Further, if the deposition thickness is 1μ or more, it is sufficient to improve the abrasion resistance, but in this embodiment, it is about IOμ, so the amount of protrusion is large, and the contact between the contact portion 22a and the ink ribbon 6 is prevented. It can be made more reliable and better records can be made.

Furthermore, in the second embodiment, when the NiP alloy is plated and further heat treated at 250°C for 1 hour, the Vickers hardness increases to about 700, and the number of durable characters when using 29 becomes 5 x 107. lX106
Durability is further improved.

In each of the above embodiments, the multi-stylus head 11.21 was provided with the return electrode 3, but it is of course possible to form the multi-stylus head with only the embedding member and the needle-shaped electrode by leaving the return electrode 3 separate. can. However, by integrating the return electrode 3, the device becomes more compact when used in a recording device.

As explained above in part, according to the present invention, since at least the contact portion is formed to have a Vickers hardness of 100 or more, the abrasion resistance of the needle electrode can be improved, and recording quality due to abrasion can be improved. The timing of deterioration of the multi-stylus head can be delayed compared to the conventional method, and the durability of the multi-stylus head can therefore be improved.

[Brief explanation of drawings]

Figure 1 is a schematic perspective view showing a recording device using a conventional multi-stylus head, Figure 2 is a diagram showing part of the head contact surface of a conventional multi-stylus head, and Figure 3 is a diagram showing a recording device using an electric transfer recording method. A schematic diagram for explanation; FIG. 4 is a diagram showing a part of the head contact surface according to the first embodiment of the multi-stylus head of the present invention; FIG. 5 is a diagram showing a multi-stylus head according to the second embodiment of the present invention. FIG. 6... Ink ribbon, 11.21... Multi stylus head, 12, 2.2... Needle electrode, 12a, 2
2a...Contact part. Applicant Ricoh Co., Ltd. Figure 1 Figure 4 Figure 5

Claims (3)

[Claims] (1) A multi-stylus head in which the contact portions of a large number of needle-like electrodes embedded in a row in an embedding member slide on an ink ribbon, wherein at least the contact portions of the needle-like electrodes have a Vickers hardness of 100. A multi-stylus head characterized by the above. (2) The multi-stylus head according to claim 1, wherein the needle electrode is entirely made of a material having a Vickers hardness of 100 or more. (3) The multi-stylus spatula 1-0 according to claim 1, wherein the contact portion is made of a metal having a Vickers hardness of 100 or more.