JPH0340712B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for recording by ejecting and flying a recording liquid such as so-called ink, and particularly to an inkjet apparatus that can perform continuous and stable recording from low speeds to ultra-high speeds.

Non-impact recording methods have recently attracted attention because the noise generated during recording is so small that it can be ignored. Among these, the so-called inkjet recording method (liquid jet recording method) is an extremely powerful recording method that enables high-speed recording and can record on plain paper without the need for special fixing treatment. Various devices have been devised so far, some of which have been improved and commercialized, while others are still being put into practical use.

Such an inkjet recording device (liquid jet recording device) ejects a recording liquid called ink from an ejection orifice provided in a recording head.
Recording is performed by flying droplets and adhering them to a recording member.

Such recording devices have various structures depending on the applied recording mode, but the method of ejecting and flying the recording liquid is simple in principle.
A recording device that is known to be effective and can be applied to high-speed recording is one in which a recording head equipped with a recording device undergoes mechanical change in an electromechanical transducer in response to an electrical signal. The recording liquid inside the recording head is ejected and jetted by applying a force to the recording head, and is described in detail in specifications such as US Pat. No. 3,683,212.

The principle of ejecting droplets in the recording device shown in USP 3683212 is to apply electrical impulses (electrical signals) through lead electrodes to a cylindrical electromechanical transducer attached to the recording head. It is based on changing the volume of the pressure generating part by changing the inner diameter of the pressure generating part in a pulse manner.

That is, when the volume changes in a pulse manner in response to an electrical impulse applied to the converter, the recording liquid is ejected from an ejection orifice provided in the recording head and flies in the form of droplets, It adheres to the recording material in front of the discharge orifice. The ejected recording liquid is replenished from the inflow path leading to the pressure generation section when the volume of the pressure generation section returns to its original capacity.

Continuous and stable recording using such a recording head is possible only when the maximum droplet generation frequency is several tens of kilometres.
Since the speed is up to approximately Hz, there is a limit to high-speed recording when recording with a single recording head.

To solve this problem, a technique has been devised to increase the overall maximum recording frequency by arranging a plurality of recording heads, thereby substantially increasing the recording speed.

However, in such a case, in order to increase the resolution, it is necessary to position the array of each recording head extremely accurately. For example, a normal high-quality image requires a resolution of 10 pel/mm, but in this case, the positioning of each recording head array is reduced to 1/10th.
It is necessary to perform this with an accuracy of mm or better.

This is extremely disadvantageous in terms of head productivity and mass production, and is unsuitable for commercialization.

Moreover, such inconveniences increase exponentially as the number of arranged recording heads increases, and the problem of head production hold-up increases dramatically.

In addition, the wiring of the lead electrodes for inputting signals to each recording head becomes more complicated as the number of recording heads to be wired increases, and consideration of electrical insulation between each lead electrode becomes a problem. come.

The present invention has been proposed in order to improve the above-mentioned problems, and it is possible to eliminate the complexity of electrical wiring and to easily and reliably achieve positioning of recording head elements and almost simultaneous electrical connection. An object of the present invention is to provide an inkjet device having the following configuration.

In addition, the complicated electrical wiring for multiple recording head elements is eliminated, and the positioning of the recording head elements is performed with high accuracy almost simultaneously with the electrical connection, so that the landing point of the ejected ink on the recording member is extremely accurate.
The purpose of this invention is to provide an inkjet device that is optimal for high-resolution, high-speed recording.

The present invention has been proposed to achieve the above-mentioned object, and includes a recording element that includes an ejection section that ejects ink droplets and an electrode that receives an electric signal for ejecting ink from the ejection section. An inkjet device for recording on a recording medium includes a mounting member having a lead electrode for inputting a recording signal to the recording element and an opening for mounting the recording element, and the mounting member has an opening for mounting the recording element. By being inserted into the opening of the member, electrical connection with the lead electrode is achieved, and by positioning and fixing the recording element with the ejection surface protruding from the surface of the mounting portion, recording is performed. It is characterized in that it is configured to be performed.

The present invention will be specifically described below with reference to the drawings.

FIG. 1 is a perspective view schematically showing the structure of a preferred embodiment of the recording head of the present invention.

The recording head 1 shown in FIG. 1 has a structure in which nine recording head elements 2 are each fitted and fixed in each opening 4 of a jig 3 in a 3×3 matrix. .

In FIG. 1, only two recording head elements 2 are shown to avoid complication of the diagram, but
Openings 4-2, 4-3, 4-5, 4-6, 4-
7, 4-8, and 4-9 also have openings 4-1,
Similarly to 4-4, the recording head element 2 is fitted and fixed.

The recording head element 2 is, for example, USP3683212,
Those having a structure similar to those described in publications such as USP3832579 can be used.

However, the difference from the recording head element described in the above publication is that lead electrodes for inputting drive signals to the recording head element are arranged on the jig 3 in the case of the present invention. It is.

The structure and characteristics of the recording head element 2 preferably used in the present invention will be described in detail below with reference to FIG.

The recording head element 2 shown in FIG. 1 includes a cylindrical member 5 having a hydrodynamically substantially smooth inner wall surface and made of a relatively hard material, and an outer periphery of the cylindrical member 5. It includes a fixedly installed cylindrical electrical/mechanical converter 6. The cylindrical member 5 normally has an inlet side for introducing liquid from a liquid supply section (not shown) provided at a location other than the recording head 1 through a supply pipe 7 provided as necessary. an end 8, a discharge port side end 10 provided with a discharge orifice 9 for discharging the liquid in the cylindrical member 5, an inflow port side end 8, and a discharge port side end 10.
and a pressure generating section 11 located between.

The circular cross-sectional area of the pressure generating section 11 is
is approximately constant over the entire length of the discharge port side end 1
0, the circular cross-sectional area gradually decreases from the pressure generating portion 11 side, and a discharge orifice 9 is formed at the end thereof. The inlet side end portion 8 has a circular cross-sectional area that is equal to or approximately equal to the circular cross-sectional area of the pressure generating portion 11 over the entire length, and an inlet is formed at the end of the inlet side end portion 8 for conversion. It is located outside the area surrounded by the body 6. The cylindrical member 5 is provided with a supply pipe 7 at the inlet end 8 for guiding the liquid supplied from the liquid supply section to the pressure generation section 11 . The supply pipe 7 is made of a viscoelastic material such as polyvinyl chloride, has an inner diameter smaller than at least an outer diameter of the cylindrical member 5, and has one end expanded to accommodate the flow of the cylindrical member 5. Inlet side end 8
At least a portion of the tube is inserted and its outer circumference is tightly tightened.

The electrical/mechanical converter 6 surrounds at least a portion of the central axis of the pressure generating section 11 and
The cylindrical member 5 is fixed to the outer periphery of the cylindrical member 5 in a substantially acoustically continuous coupling relationship so as to effectively supply pulsed pressure waves to the liquid within the cylindrical member 1 .
An outer electrode layer 12 is provided on the outer wall surface of the converter 6 in order to input an electrical impulse given to the converter 6 to change the volume of the pressure generating part 11 in a pulse-like manner and cause the droplet to fly out from the discharge orifice 9. An inner electrode layer 13 is provided on the inner wall surface. The inner electrode layer 13 is drawn out toward the outer electrode 12 at the end 8 on the inlet side in order to facilitate electrical connection with other parts. The outer electrode 12 and the inner electrode 13 are electrically connected to lead electrodes arranged in a predetermined pattern on the surface of the jig 3, respectively, when the recording head element 2 is fitted and fixed to the jig 3. Ru.

The recording head element 2 has no eccentricity and no uneven thickness within the accuracy required for accurate landing of droplets on the recording surface, and has an orifice 9 along an axis passing through the center of the inner diameter of the converter 6. In order for the center to be located, it must be done statistically and manufacturing accurately. In the jig 3, openings 4 into which the recording head elements 2 are inserted are bored at a highly accurate pitch in order to accurately arrange the recording head elements 2.

and the recording head element 2 inserted into the opening 4
are precisely positioned and fixed by the front and rear members forming the jig 3.

When the jig 3 is made of an electrically insulating material, the lead electrode 14 is printed on the surface of the jig 3 by a commonly used method, and the lead electrode 4 and the recording head are arranged up to the inside of the opening 4. By ensuring electrical contact between each electrode layer of the element 2, an electrical signal for ejecting a droplet can be input to each recording head element 2.

The material constituting the jig 3 must have openings 4 drilled with high precision so that the recording head elements 2 can be arranged and fixed with high precision, be easy to process, and be resistant to mechanical shock. The material is selected from those that are strong or have a structure that has as little dependence of the material on external atmosphere such as temperature.

Such materials include, for example, photosensitive glass commercially available under the trade name Photoceram, or ordinary glass, quartz, etc. as electrically insulating materials.
Alternatively, examples include those that are relatively hard and easy to process, such as acrylic resins and styrene resins.

Other materials include stainless steel,
Metals such as copper, silver bronze, and brass can be used, but when metal is used, after the opening 4 is provided, the surface is electrically insulated, and then the lead electrode group is arranged. It is necessary to do it.

In order to accurately drill the opening 4 in the jig 3, etching is the most preferable method, so it is desirable to select and use a material suitable for etching from among the materials listed above.

In the present invention, when the jig shown in FIG. 1 was made, good results were obtained with Photoceram manufactured by Konin Co., Ltd.

In the case of the recording head 1 shown in FIG. 1, the positional wear of the fixed recording head element 2, the mechanical strength of the recording head 1 itself, and furthermore the electrical contact between each of the recording head elements 2 is avoided. Therefore, it is desirable that the entire recording head 1 be molded with electrically insulating resin.

FIG. 3 is a schematic perspective view of another preferred embodiment of the recording head of the present invention.

The recording head 15 shown in FIG. 3 has the same basic structure as the recording head 1 shown in FIG. The difference is that a lead electrode wire 18 is electrically connected to the electrode 13.

In FIG. 3, as in the case of FIG. 1, inside the opening 4 provided in the jig 17, 4-1, 4-4
The recording head element 16 is fitted and fixed only in the openings 4-2, 4-3, 4-5, 4-.
6, 4-7, 4-8, and 4-9, the recording head elements 16 are omitted and not shown. Furthermore, lead electrodes 19 are not shown in the openings 4-5 to 4-9, but in actual case, the openings 4
Lead electrodes are provided in each of the cases -1 to 4-4.

By assembling the recording head shown in Figures 1 and 3, the deviation of the landing point of droplets on the recording surface can be reduced by ±
It can be suppressed to within 10 μm and is not a problem when recording with a resolution of 10 pel/mm.
It has been possible to obtain a multi-orifice type recording head that can perform accurate printing and can eliminate the complexity of wiring because matrix wiring can be performed extremely easily.

According to the inkjet device of the present invention, since the heads can be arranged with high positional accuracy, the landing point of the ejected droplets can be made extremely accurate. In addition, by mounting the head elements in the openings of the mounting member, each head element and the lead electrodes wired in high density are electrically connected reliably, making head positioning and electrical connection reliable and easy. can be done.

In addition, the complicated electrical wiring for multiple recording head elements is eliminated, and the positioning of the recording head elements is performed with high accuracy almost simultaneously with the electrical connection, so that the landing point of the ejected ink on the recording member is extremely accurate.
It is possible to provide an inkjet device that is optimal for high-resolution, high-speed recording.

[Brief explanation of drawings]

1 and 3 are perspective views schematically showing the configuration of a preferred embodiment of the recording head of the present invention, and FIG. 2 shows an example of recording head elements constituting the recording head of the present invention. FIG. 2 is a schematic cross-sectional view of the configuration. 1, 15... Recording head, 2, 16... Recording head element, 3, 17... Jig, 4... Opening, 5
...Cylindrical member, 6...Electrical/mechanical converter, 7...
... Supply pipe, 8 ... Inlet side end, 9 ... Orifice, 10 ... Discharge port side end, 11 ... Pressure generating section, 12 ... External electrode, 13 ... Inner electrode, 14
...Lead electrode, 18...Lead electrode.

Claims (1)

[Scope of Claims] 1. An inkjet device that performs recording on a recording medium using a recording element that includes an ejection portion that ejects ink droplets and an electrode that receives an electric signal for ejecting ink from the ejection portion, comprising: A mounting member is provided with a lead electrode for inputting a recording signal to the recording element, and has an opening for mounting the recording element, and when inserted into the opening of the mounting member, the recording element is inserted into the mounting member. The recording element is characterized in that recording is performed when electrical connection with the lead electrode is achieved and the recording element is positioned and fixed with the ejection surface protruding from the surface of the mounting member. Inkjet device. 2. The mounting member includes a plurality of openings to which a plurality of recording elements can be mounted, and a lead electrode for independently inputting a recording signal to each recording element for each opening. An inkjet device according to claim 1.