JP2707658B2 - Inkjet recording method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an on-demand type ink jet recording method, and particularly to an ink jet recording method with improved printing stability.

2. Description of the Related Art As shown in FIG. 1, an on-demand type ink jet recording apparatus basically includes an ink ejection head 10, an ink supply pipe 1,
6. The ink tank 17 is formed, and the piezoelectric element 11 bends in response to an electric signal to compress the ink in the cavity 13 and eject it as ink droplets from the nozzle orifice 12 to perform recording.

In the recording method, when the bubbles staying in the cavity 13 absorb the pressure when the electric signal is applied and the piezoelectric element is bent, a stable ink droplet is not generated from the nozzle orifice, or the ink droplet itself is not generated. It has been found that it has a very weak point against bubbles, such as adversely affecting printing. Therefore, it is a very important problem in the on-demand type ink jet recording method whether the bubbles in the cavity can be quickly discharged.

Ink-based members consisting of ink ejection heads, ink supply pipes, and ink tanks are made of various types of materials, but most of them are made of plastic due to moldability, cost, and other required characteristics. It is. Further, plastics have been widely studied because they have sufficient merits as ink jet head materials, such as being mass-producible, being moldable, being weldable, being excellent in chemical resistance, and being low in cost.

However, when the ink-based member is made of plastic, the liquid generally has a characteristic that the surface energy is low and the liquid is hardly wetted, which causes a problem that printing stability is not good.

Attempts have been made to treat the surface of the plastic to increase its wettability before use.

[Problems to be Solved by the Invention] However, the surface treatment of plastics has problems such as complicated processes, problems in persistence of treatment effects, and a significant increase in cost. is the current situation.

Accordingly, an object of the present invention is to provide an ink jet recording method which is excellent in printing stability and can provide high printing quality without impairing the low cost characteristic of plastic.

[Means for Solving the Problems] According to the present invention, in an ink jet recording method, the ink-based member is made of plastic, and the foaming power of the ink obtained by the foaming power of JIS3362-1970 and the foam stability test method is used. , 10 to 200 mm or an ink having a foam stability of 10 to 200 mm. Further, the ink jetting head is made of glass, the ink supply pipe and the ink tank are made of plastic material, and the foaming power of the ink obtained by the foaming power and the foam stability test method of JIS3362-1970 is 10%.
From 200 to 200 mm, or from 10 to 200 mm in foam stability. In addition, the ink ejection head is made of plastic material for
The ink is characterized by using an ink having a foaming power of 50 to 200 mm or a foam stability of 50 to 200 mm obtained by the foaming power and foam stability test method of 362-1970.

 Hereinafter, the present invention will be described in more detail.

The present inventors have studied the improvement of the wetting of plastics, which are ink-based members, by adding additives to the ink, and found that bubbling of the ink has a great effect on recording characteristics such as print stability and print quality. I understand. Therefore, as a result of measuring the foaming of the ink by the foaming power and the foam stability test method of JIS3362-1970, the foaming power of the ink was
It was found that the use of an ink having a bubble stability of 10 to 200 mm or a bubble stability of 10 to 200 mm satisfies both printing stability and printing characteristics such as printing quality. When the ink ejection head is made of a plastic material, JIS3362-1
The foaming power of the ink obtained by the 970 bubble power and foam stability test method is 50 to 200 mm, or the foam stability is 50 to 2
It was found that the recording characteristics such as printing stability and printing quality were satisfied when the ink having a thickness of 00 mm was used.

As the plastic of the ink-based member, plastics satisfying required characteristics such as flexibility, heat resistance, molding accuracy, ink resistance, gas permeability, and cost can be appropriately selected. Specifically, polyethylene, polypropylene , Nylon, vinyl chloride, polyacetal, teflon, acrylic resin,
AS resin, ABS resin, and the like.

The plastic head used in the present invention is made of polysulfone, polycarbonate, polyethersulfone,
It is preferable to use an amorphous resin such as polyetherimide, but plastics other than those described above can be used as long as the required characteristics are satisfied.

EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples.

First, an ink was prepared by changing the addition amounts of potassium oleate and sodium laurate as additives for improving plastic wettability based on the following <Ink composition a> as a basic composition. Tables 1 and 2 show the addition amount and JI
The foaming power obtained by the foaming power and foam stability test method of S3362-1970, and the result of foam stability are shown.

<Ink Composition a> Dye Direct Black 19 1% Solvent Glycerin 10% Water * Remaining Using the inks shown in Tables 1 and 2, the following recording characteristics were evaluated.

Print recovery test In continuous printing, the recovery time is measured in the event of troubles such as missing dots or printing irregularities. The return operation is based on a method of sucking 2 ml of ink per minute from a head nozzle side by a pump.

Printing stability test Continuous printing is performed, and the total number of printing lines is divided by the number of missing dots during that period to calculate the average number of printing lines. If the value is 50,000 lines or more, it is determined to be good.

Print quality Print on Xerox P (Fuji Xerox) to determine the presence or absence of bleeding, and to determine the quality without bleeding.

Further, the recording characteristics were evaluated under three optimum conditions using the members shown in Table 3 as the ink ejection head, the ink supply pipe, and the ink-based members of the ink tank under the respective optimum conditions.

As shown in Tables 4, 5 and 6, if the foaming power and foam stability are too large or too small, each recording characteristic cannot be satisfied. Therefore, from the above results, the type of additive,
Regardless of the addition amount, the foaming power obtained by the foaming power and foam stability test method of JIS3362-1970 is 10 to 200 mm,
Alternatively, it was found that the ink jet recording characteristics sufficiently satisfying the required characteristics can be obtained by using an ink having a bubble stability of 10 to 200 mm. If the ink ejection head is made of a plastic material in ink-based members, JIS3
An ink jet recording method that satisfies the required properties by using an ink having a foaming power of 50 to 200 mm or a foam stability of 50 to 200 mm obtained by the foaming power and foam stability test method of 362-1970. Can be obtained.

Further, an ink having the composition shown in Table 7 was prepared and subjected to JIS3362.
Measure the foaming power and foam stability of -1970, and evaluate the same print recovery test, print stability and print quality as described above by the methods of No. 1 and No. 2 consisting of the components shown in Table 3. did.

Tables 8 and 9 show the results.

In the ink-jet recording method in which the ink-based member is made of plastic, the ink obtained by the foaming power and foam stability test method of JIS3362-1970 regardless of whether it contains an additive such as a surfactant or the properties of the dye. By using an ink having a foaming power of 10 to 200 mm or a foam stability of 10 to 200 mm, an ink jet recording method having excellent printing characteristics can be obtained. In the case of an ink member, when the ink ejection head is made of a plastic material, the foaming force obtained by the test method of JIS3362-1970 is 50 to 200 mm, or the stability of the foam is 50 to 200 mm.
By using the ink, it is possible to obtain an ink jet recording method satisfying the required characteristics.

[Effects of the Invention] According to the present invention, in a head made of plastic having poor wettability, troubles such as missing dots can be quickly eliminated. Further, even if the wettability to plastic is increased, the wettability on paper is maintained at a level without bleeding, and high quality printing can be obtained.

In addition, there was a demerit of foaming as an adverse effect to obtain wetness, but the ink of the present invention can be used by managing foaming power and foam stability, so there is no trouble due to foam including printing stability. , Sufficient recording characteristics.

In addition, there has been a process of improving the wettability of plastics by performing surface treatment on the plastics to improve the wettability. However, such a process can be omitted, and low cost and mass productivity of plastics can be achieved. The benefits can be fully utilized.

[Brief description of the drawings]

FIG. 1 is a principle diagram of an on-demand type ink jet recording apparatus.

Claims (3)

(57) [Claims] 1. An ink jet recording apparatus in which at least a part of an ink-based member is made of a plastic material,
The foaming power of the ink obtained by the foaming power and foam stability test method of 362-1970 is 10 to 200 mm, or the foam stability is 1
An inkjet recording method using an ink that is 0 to 200 mm. 2. The ink jet recording apparatus according to claim 1, wherein said ink jet recording apparatus comprises an ink jet head made of glass, an ink supply pipe made of a plastic material, and an ink tank.
Item 7. The ink jet recording method according to the above item. 3. An ink jet recording apparatus provided with an ink jet head made of a plastic material has a foaming power of 50 to 200 mm or a foaming power of an ink obtained by a foaming power and foam stability test method of JIS3362-1970. An inkjet recording method using an ink having a stability of 50 to 200 mm.