JPH0311903B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for implementing so-called inkjet recording, and in particular, to eject recording ink as small droplets in a predetermined direction from a plurality of ejection orifices arranged in parallel. The present invention relates to a droplet jet recording apparatus that performs recording by attaching at least a portion of droplets to a recording surface.

Among the various recording methods currently known, it is a non-impact recording method that generates almost no noise during recording, is capable of high-speed recording, and does not require special fixing treatment on plain paper. The so-called inkjet recording method, which can perform recording on images, is recognized as an extremely useful recording method. Various methods have been proposed for this inkjet recording method, some have been improved and commercialized, and others are still being worked on to put them into practical use. be.

In short, the inkjet recording method involves flying droplets of a recording liquid called ink.
Recording is performed by attaching it to a recording member such as paper. The inkjet recording method is roughly divided into several types based on the method of generating recording liquid droplets and the control method for controlling the flying direction of the generated droplets.

Among them, one of the representative methods is, for example
USP3596275 (Sweet method), USP3298030 (Lewis
and Brown method), etc., in which a droplet flow with a controlled amount of charge is generated by a continuous vibration generation method, and this droplet flow with a controlled amount of charge is uniformly distributed. By causing the droplet to fly between deflection electrodes to which an electric field is applied, recording is performed on the recording member while controlling the flying trajectory of the droplet. This method is also generally referred to as a continuous method.

Other typical methods that can be compared with this are, for example,
This is the method (Stemme method) disclosed in USP3747120. In this method, an electrical recording signal is applied to a piezo vibrating element attached to a recording head that has an orifice for ejecting liquid for recording, and this electrical recording signal is applied to the mechanical vibration of the piezo vibrating element. Recording is performed by ejecting droplets from the orifice and adhering them to the recording member whenever necessary according to the mechanical vibration.

This is the so-called on-demand method. Separately, a new recording method that differs in principle and idea from these methods is also based on the applicant's earlier application (that is, the patent application filed in
52-118798). In short, this new method applies a thermal pulse as an information signal to the recording liquid introduced into the liquid chamber, and the liquid changes its state. Discharging and flying the liquid as small droplets from an orifice attached to the chamber,
This is a method in which recording is performed by attaching this to a recording member.

However, with respect to the various inkjet recording methods exemplified above, there still remain technical problems common to all of them that must be solved.

One of these was to develop a recording device with a multi-array of ink droplet ejection orifices in order to speed up recording using ink droplets. In order to improve resolution, it is necessary to develop a recording device that can stably eject uniform ink droplets at high density.

Furthermore, it is necessary to complete a recording device with a highly accurate and minute structure.

However, it is not easy to satisfy these conditions required for such a recording apparatus, especially from the viewpoint of manufacturing the apparatus.

For example, as in the conventional method, one nozzle part is made up of fine holes, and multiple nozzles are combined to complete a multi-array type recording device. requires technical ability. Since each of its constituent elements is required to be homogeneous, it is not easy to manufacture it with a good yield.

As described above, when a recording device in which each component itself is minute and precise is constructed into a multi-array structure, it is accompanied by further technical difficulties. In view of the current state of inkjet recording technology, the present invention aims to provide a droplet jet recording device with a new configuration that satisfies the problems listed in the above items, in other words, the manufacturing thereof is improved. The main objective is to provide a droplet jet recording device that is simple and can perform high-precision recording, and can perform high-quality recording at high speed.

Another object of the present invention is to provide a multi-orifice array type droplet jet recording device that can be manufactured easily and with high precision.

Furthermore, it is another object of the present invention to provide a multi-orifice array type droplet jet recording device that is equipped with lead electrodes suitable for driving the working portion thereof in a matrix manner. Therefore, the purpose of the present invention is to eject recording ink as small droplets from a plurality of ejection orifices arranged in parallel, and to make at least a portion of the small droplets adhere to a recording surface. In a droplet jet recording device that performs recording, a plurality of action parts and lead electrodes for connecting to the action parts and inputting electric signals are molded and attached to the substrate surface, and This can be achieved by a droplet jet recording apparatus characterized in that each chamber is provided with a chamber that communicates with the orifice and stores the ink before it is ejected.

The invention will now be explained in detail with reference to illustrated embodiments.

First, one embodiment of the present invention will be explained using FIGS. 1 and 2.

Note that FIG. 1 depicts only the recording head portion in an exploded view for convenience of explanation, and does not show details such as the recording ink supply system or the drive circuit for this head. Also, the recording head in Figure 1 is
In reality, the heating resistors 2 ₁ , 2 ₂ . . . act as working parts.
..., 2n, and a grooved plate 4 provided with long grooves 3 ₁ , 3 ₂ ..., 3n, which serve as ink storage chambers.
are joined and integrated with each other such that the heating resistor and the elongated groove are in corresponding positions.

Then, a heating resistor 2 ₁ formed on the substrate 1,
2 ₂ ..., 2n further includes resistors 2 ₁ , 2 ₂ ...,
2n with individual lead electrodes 5 ₁ , 5 ₂ ..., 5n,
Common lead electrode 6 ₁ shared by several resistors,
6 ₂ ..., 6m are connected respectively. The individual lead electrodes 5 ₁ , 5 _{2 .} . . 5n are connected to a matrix wiring 7 in the middle of being drawn out, and are drawn out from there to l terminals 8 ₁ , 8 ₂ .
Further, the common lead electrodes 6 ₁ , 6 _{2 .} . . 6m are drawn out along the back surface of the substrate 1 to the respective terminals 6 ₁ ′ . . . 6m′, as shown in FIG.

In this illustrated example, after recording ink is introduced into each long groove 3 ₁ , 3 _{2 .} . . , 3n from an ink supply system (not shown), the terminals 8 ₁ , 8 ₂ . 8l
and heating resistors 2 ₁ , 2 ₂ ... via 6 ₁ ′...6m'
..., 2n are input with electric pulse signals. Then,
According to the input of the electric pulse signal, the heating resistor 2 ₁ ,
2 ₂ . As a result, ink is ejected in the form of small droplets 10 from the orifice formed by the side edge of the elongated groove, which is lined up on the thick line 9 in the figure. These small droplets 10 fly at a speed corresponding to the intensity of the acting force and adhere to a recording material (not shown), thereby performing recording with ink droplets. At this time, the size (diameter) of the ink droplet 10 ejected from the orifice and flying is determined by the amount of electrical energy input to the heat generating resistor as information, the transfer efficiency of the thermal energy converted there to the ink, Energy conversion efficiency of the resistor, diameter of the orifice, inner diameter of the groove, distance from the orifice position to the resistor, acting force applied to the ink, amount of ink affected, specific heat, thermal conductivity, boiling point of the ink used, Determined depending on latent heat of vaporization, etc.

Therefore, by changing one or more of these factors, the size of the ink droplet 10 can be easily controlled, and the recording material can be formed with any droplet diameter or spot diameter. A record can be made above.

Incidentally, the heating resistors 2 ₁ , 2 _{2 .} . . 2n can be classified into thick film type, thin film type, and semiconductor type depending on their form, but in this embodiment, they may be any of these types.
However, especially when high-speed, high-resolution recording is desired, it is currently desirable to use a thin film type.

The ink used in the device of the present invention is prepared by dissolving a wetting agent such as ethylene glycol, a surfactant, various dyes, etc. in a main solvent such as water, alcohol such as ethanol, or toluene. Or they are created in a distributed manner. In addition, in order to avoid clogging the ejection orifice, it is effective to filter the ink after it is created or to install a filter in the ink flow path, just as in the case of existing inkjet recording methods. .

By the way, in the illustrated example device, the structure and extraction method of the lead electrodes as illustrated were devised for the following two reasons.

In other words, 1. Since the orifices, which are generally minute in diameter of about 5 to 250 μm, should not be blocked, it is virtually impossible to provide lead electrode extraction terminals on the orifice row 9 side, and 2. Of the lead electrodes, In particular, this is intended to secure installation space for the common lead electrode in a narrow area on the substrate. Note that the distance between the orifice array 9 and the array of heating resistors 2 ₁ , 2 ₂ . Therefore, there is a strong tendency for unstable ejection of ink droplets to occur frequently), and the intervals between them inevitably become very small, making it difficult to secure an effective installation space for the lead electrodes there.

As described in detail above, the lead electrode extraction method as shown in the drawings is particularly effective when a large number of action parts for ejecting ink onto the same substrate surface are arranged at high density.

Next, another embodiment will be described with reference to FIG. In this third illustrated example, the heating resistor installation board 1
Although the structure of the recording head portion (not shown) and the principle of ejecting ink droplets are substantially the same as those in the first illustrated example, a description thereof will be omitted.

n heating resistors 2 ₁ , 2 ₂ . . . provided on the substrate 1;
..., 2n, respectively, separate lead electrodes 5 ₁ , 5 ₂ ...
..., 5n are drawn out to each individual terminal 5 ₁ ', 5 ₂ '..., 5n'. On the other hand, the lead electrode 11 common to the resistors 2 ₁ , 2 ₂ . After being pulled out in a direction parallel to , it is pulled out to a terminal 12 set at an end of the substrate 1 spaced apart from the resistor array. Next, a grooved plate (not shown) (having n long grooves corresponding to the resistors 2 ₁ , 2 ₂ . . . , 2n) necessary for ejecting ink droplets is mounted on the illustrated substrate 1. Of course.

A common feature of the above-mentioned illustrated examples is that, for the purpose of achieving stable ejection of ink droplets, the distance between the orifice row and the row of action portions represented by heating resistors is shortened. The extraction terminals of the lead electrodes are centrally arranged on the side opposite to the orifice row, sandwiching the action section row. By the way, another feature of the present invention is consideration for keeping the voltage applied to the action parts substantially constant in all action parts regardless of the recorded information. This means that using thin film electrodes whose resistance cannot be ignored,
This becomes particularly important when applying electrical pulse signals to a large number of action parts simultaneously. An effective means to solve this problem is to lower the resistance of the common lead electrode. One of the concrete measures is shown in FIG.

The fourth illustrated example will be described as a modified example of the third illustrated example.

In the fourth illustrated example, among the lead electrode parts formed thinly on the substrate 1 by vapor deposition or sputtering, the orifice row 9 of the common lead electrode 11 and the heating resistors 2 ₁ , 2 ₂ . . . , 2n is deformed by making it a thick film by plating or by embedding a metal rod, etc., so that the electrical resistance of the common lead electrode 11 is regulated within a narrow area. Efforts are being made to lower the

When the illustrated device is driven by a constant voltage power supply, a constant voltage V is applied between the terminals 5 ₁ ′, 5 ₂ ′ . . . , 5n′ and the common lead electrode terminal 12.

At this time, when a plurality of resistors are driven at the same time, the greater the number, the greater the variation in the voltage applied to each resistor. If this is done, it is possible to suppress variations in the voltages applied to the individual heating resistors 2 ₁ , 2 ₂ . be.

However, in the case of matrix driving, this fourth
Compared to the illustrated example device, the illustrated example device according to FIGS. 1 and 2 is advantageous.

FIG. 5 shows still another example of the configuration of the heating resistor installation board 1.

This FIG. 5 is a top view of the substrate 1, and one side of the lead electrodes 14 ₁ , 14 _{2 .} . . , 14 connected to n heating resistors 13 ₁ , 13 ₂ .
Fold each n on the same surface as shown,
These are connected to a low resistance common electrode 16 ₁ on the insulating layer 15,
..., 16 m long and its terminal 16 ₁ ', ...,
It is taken out from the board 1 from 16 m'. on the other hand,
The individual lead electrodes 17 ₁ , 17 ₂ . . . , 17n are connected to fewer than n terminals 19 via the matrix wiring section 18
₁ , 19 ₂ ..., 19l to the outside of the substrate 1. Further, thick lines 20 indicate the rows in which the orifices are installed.

The first advantage of this fifth illustrated example is that the orifice row 20 and the heating resistors 13 ₁ , 13 ₂ ..., 13n
The distance from the installation row can be arbitrarily shortened.
In addition, all the lead electrodes can be set over a fairly wide area with plenty of room.

The second advantage is that, unlike the illustrated example shown in FIGS. 1 and 2, all component patterns are formed on the same substrate surface, making it easier to handle with photolithography, etc.; and the third advantage is that Obtained substrate 1
Even when the surface of the orifice row is polished and shaped after a grooved plate (not shown) is bonded to the plate, there is no risk of damaging the lead electrode.

FIG. 6 is a modification of FIG. 5, in which two heating resistors are provided for each working chamber (not shown). In the sixth illustrated example, two heating resistors 13 ₁ and 1 are provided in n working chambers (not shown), respectively.
3 ₁ ', 13 ₂ , 13 ₂ '..., 13n, 13n' are arranged. Note that other elements equivalent to those in the fifth illustrated example are designated by the same reference numerals. The sixth illustrated example has an advantage over the fifth illustrated example in that it is easier to match the masks at the manufacturing stage.

An example of the structure of the lead electrode is shown above in FIG. 5 or 6.
The present invention is not limited to the illustrated example in the figure.

For example, as shown schematically in FIGS. 7 and 8,
It is also possible to configure three to four folded lead electrodes to correspond to one action chamber.

Here, the embodiment based on FIG. 5 will be further explained in detail.

Example 4 μm RF of SiO ₂ on 60 mm x 90 mm alumina substrate 1
Sputtering and further using HfB ₂ as a heating resistor,
After continuous sputtering of Al as an electrode, a pattern similar to that shown in FIG. 5 was formed by selective etching. Lead electrode parts 13 ₁ , 14 ₁ , 13 ₂ , 1
4 ₂ ..., 13n, 14n width is 40μm, pitch is
It is 50 μm. Also, the size of each heating resistor is the width
The length is 40 μm, the length is 300 μm, and the pitch is 100 μm. The resistance value of each heating resistor was 200 ohms, and the resistance value of each lead electrode was 20 ohms. Fifty lead electrodes 14 ₁ , 14 _{2 .} . . , 14n were taken out from the terminals 16 ₁ ′ .
Note that at this time, n=500 and m=10. Insulating layer 1
In No. 5, a 5 μm thick SiO ₂ sputtered film was used. and,
In part 18, matrix wiring was used.

On this substrate 1, a width of 40 μm and a depth of 40 μm and a pitch of 100 μm are provided.
After gluing a glass plate with m-grooves so that each groove corresponded to the heat generating resistor, the orifice surface was polished to set the distance between the orifice row 20 and the heat generating resistor installation row to 1 mm. . While supplying ink to the device obtained in this way, a rectangular wave of 40 volts and 10 μsec was applied to each resistor at a cycle of 500 μsec, and ink droplets were ejected stably in response to the electric signal. It was done. No change in print quality was observed between when all 50 lead electrodes were energized and when only one was energized.

The embodiments of the present invention have been described above by taking as an example an ink ejecting method using thermal energy, but the present invention also relates to an ink ejecting method having an action part having a piezoelectric element or other lead electrode for inputting an electric signal. It also suggests techniques that are equally effective for other systems.

The present invention has a large number of working parts at a high density (e.g. 8
It can be effectively adapted to inkjet recording systems that are lined up (on the order of 16 lines/mm to 16 lines/mm).
Further, the folded lead electrodes do not necessarily need to be combined into one wire, and can be taken out of the substrate by bonding or the like.

In the present invention, insulating materials and protective materials are applied to heat-conducting materials to prevent the heating resistors and lead electrodes formed on the substrate from leaking current or coming into direct contact with the recording ink. It is also desirable to cover it to the extent that it does not damage it.

As described in detail above, the present invention provides a droplet jet recording device in which a large number of working chambers for ejecting ink droplets are arranged in a high-density cluster with high accuracy.

In addition, it is easy to manufacture, and its printing quality is also extremely good.

[Brief explanation of drawings]

1 and 2 are schematic perspective views for explaining one embodiment of the present invention, and FIGS. 3 to 8 are schematic perspective views of an apparatus for explaining other embodiments of the present invention, respectively. This is a schematic diagram depicting only the main parts. In the figure, 1 is the substrate, 2 ₁ , 2 ₂ ..., 2n, 1
3 ₁ , 13 ₂ ..., 13n, 13 ₁ ′, 13 ₂ ′ ...,
13n' is a heating resistor, 3 ₁ , 3 ₂ ..., 3n is a groove,
4 is a grooved plate, 5 ₁ , 5 ₂ ..., 5n, 6 ₁ , 6 ₂ ...
...,6m,11,14 ₁ ,14 ₂ ...,14n,1
7 ₁ , 17 ₂ ..., 17n are lead electrodes, 5 ₁ ', 5
₂ ′……, 5n′, 6 ₁ ′……6m′, 8 ₁ , 8 ₂ …, 8
l, 12, 16 ₁ ′..., 16m', 19 ₁ , 19 ₂ ...
..., 19l are terminals, 7 and 18 are matrix wiring parts, and 9 and 20 are orifice rows.

Claims (1)

[Claims] 1. A plurality of working parts formed by a heating resistor provided on a substrate and a pair of electrodes electrically connected to the heating resistor, and a discharge orifice provided corresponding to the plurality of working parts, respectively. In a droplet ejection recording device having a plurality of ejection orifices and a chamber that is connected to the plurality of ejection orifices and can accommodate ink ejected from the ejection orifices, one of the electrodes is folded back within the same plane, and one of the electrodes is folded back within the same plane; A droplet jet recording device characterized in that at least one of the electrodes is a common electrode.