JP3149491B2 - Inkjet recording method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-demand type ink-jet recording method, and more particularly to an ink-jet recording method in which the flight characteristics of ink are improved and high print quality is applicable to plain paper.

[0002]

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 16 and an ink tank 17 are provided. The piezoelectric element 11 bends in response to an electric signal, whereby the ink in the cavity 13 is compressed and ejected from the nozzle orifice 12 as ink droplets to perform recording.

In this recording method, ink is ejected from a nozzle.
To time, adversely affect the wettability printing stability of the nozzle front and found to be or to induce flying curve of the ink, how to control the wettability of Roh nozzle front is a major challenge I have. Also, the ink-based members consisting of the ink ejection head, the ink supply pipe, and the ink tank are made of various 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, moldable, weldable, excellent in chemical resistance, and low in cost.

However, when the ink discharge head is made of plastic, the liquid generally has a characteristic that the surface energy is low, so that the liquid is hardly wetted. As a result, as described above, the print stability is adversely affected, and the flight bending occurs. This causes a problem of deteriorating the print quality. Conventionally, treatments with chemicals, plasma treatment, UV treatment, etc. have been performed to make the plastic surface easily wettable. However, the process is complicated, there is a problem with the persistence of the treatment effect, and it is dangerous. There remain problems such as the use of chemicals and a significant increase in cost. As a countermeasure, JP-A-59-182745 proposes a method in which an aqueous solution containing a dye is brought into contact with a plastic and the dye is adsorbed to increase the wettability. However, even if the dye is adsorbed, the effect is not perfect, and depending on the type of ink used, the adsorbed dye gradually dissociates and returns to the poorly wettable plastic surface.

[0005]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to maintain the wettability effect obtained by adsorption of a dye without impairing the low cost characteristic of plastics, and to further improve the properties required for inks for ink jet recording. In other words, an ink that can support high-print-quality plain paper with a good balance of printing stability (response, ejection stability, continuous printing stability, and stability after printing is stopped), storage stability, water resistance, and light resistance. By providing the method, an ink jet recording method with high versatility is realized.

[0006]

According to the ink jet recording method of the present invention, a hydrophilic treatment solution comprising a dye and water and / or a polyhydric alcohol is brought into contact with a plastic flow path base material to cause the dye flow path base material to be dyed. At least C.I. I. An ink containing direct black 168 in a range of 0.05% to 15% is used.

The present inventors measured the contact angle after adsorption using various types of dyes to improve the wetting of the flow path substrate made of a plastic material. I. It was confirmed that the wettability when the dye was adsorbed using Direct Black 154 and water and / or a polyhydric alcohol was the best.
Further, as a result of studying an ink that maintains its wettability, at least C.I. I. It has been found that this can be achieved with an ink containing Direct Black 168 in the range of 0.05% to 15%. If it is less than 0.05%, the wettability due to the adsorption of the dye cannot be maintained, and
If it exceeds 5%, the effect can be sufficiently maintained, but the clogging is adversely affected.

The ink used in the present invention will be further described. The recording ink of the present invention contains at least C.I. I. Direct black 168 is contained in the range of 0.05% to 15%, and is composed of a dye or pigment, a wetting agent for preventing nozzle clogging, and water as a solvent. As the colorant used in the present invention, an organic or inorganic pigment, and any one or a mixture of an acid dye, a basic dye and a direct dye can be used. To give a specific example,

[0009]

[Table 1] Carbon black MA7, MA8, MA100, # 40, # 45, # 50 (Mitsubishi Kasei Kogyo) I. Pigment Yellow 1, 2, 3, 5, 12 C.I. I. Pigment Red 2, 3, 5, 16, 23, 31, 49, 57, 63 C.I. I. Pigment Blue 1, 2, 15, 16, 17 and the like.

As a dye,

[0011]

[Table 2] C.I. I. Direct yellow 12, 26,
86, 130 C.I. I. Direct Red 9, 13, 17, 23 C.I. I. Direct Blue 78, 86, 199 C.I. I. Direct black 19, 22, 28, 1
54, 168 C.I. I. Acid Yellow 23, 25 C.I. I. Acid Red 52, 254, 289 C.I. I. Acid Blue 9,254 C.I. I. Acid Black 2, 52, 172, 2
08 C.I. I. Food Black 2 and the like. The addition amount is preferably 0.5 to 10% by weight in order to obtain a sufficient color density and suppress the ink viscosity.

The wetting agent is an important component for preventing the drying of the recording ink at the nozzle of the head of the ink jet printer, and has a great influence on the printing quality and quick drying. In the present invention, glycerin, ethylene glycol,
Polyhydric alcohols selected from diethylene glycol, triethylene glycol and propylene glycol are used alone and in a mixture. The addition amount is 0.5% to 10%, preferably 2% to 7%. If it is less than 0.5%, clogging occurs, and if it exceeds 10%, the printing quality and quick-drying are adversely affected. Further, a monohydric alcohol selected from methanol, ethanol and propanol is added in order to make the ink adhere to the paper thinly. By attaching thinly, quick drying and printing quality can be improved. 1% added
To 10%, more preferably 3% to 6%
It is.

Further, other additives such as a preservative, a fungicide, a chelating agent and the like can be added as needed.

The plastic head used in the present invention is made of polysulfone, polycarbonate, polyethersulfone, polyetherimide, AS resin, ABS resin, polyethylene terephthalate, polyphenylene oxide, polyphenylene ether, polyallyl ether, polyimide, amorphous polyolefin. It is preferable to use a plastic other than the above as long as the required characteristics are satisfied. Also,
A photosensitive resin, a photoresist and the like can also be used as the head material of the present invention.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to embodiments.

The adsorption of the dye to the head can be realized by bringing the head into contact with a hydrophilic treatment solution comprising the dye and water and / or a polyhydric alcohol. That is, this can be realized by filling the head processing channel with the hydrophilic processing liquid and leaving it at a high temperature, or by circulating the hydrophilic processing liquid through the head flow path. Hereinafter, each method will be briefly described.

FIG. 2 is a schematic view of a method of filling a hydrophilic treatment liquid and leaving it to stand. 1 is a plastic ink jet head having a flow path therein, and 2 is the flow path. Reference numeral 10 denotes a treatment liquid for hydrophilically treating the inner surface of the flow channel, which is contained in the bottle 8. The head 1 is provided with a suction cap 3 capable of sucking and sealingly printing over the nozzle surface by means of a jig 4, so that the nozzle surface is sealed. The valves 5 and 6 are initially opened. The pump 9 is driven to suck the processing liquid 10, and the processing liquid 10 is filled from the bottle 8 through the head 1 to the pump 9. Thereafter, the valve 5 is closed, and the valve 6 is further closed. After the above operation is completed, the apparatus is left. The treatment can be carried out in a temperature of 40 ° C. to 70 ° C. and in a time of about 30 minutes to 2 hours, depending on the temperature.

FIG. 3 is a schematic view of a method of circulating a hydrophilic treatment liquid. The head 1, the suction cap 7, the processing liquid tank 8, and the pump 9 are left in the thermostat 10. The suction cap 7 is brought into close contact with the head 1 by operating the pump 9, and the processing liquid 2 is supplied to the head 1 from the processing liquid tank 8. Thus, the processing liquid can be circulated in the flow path of the head 1. The processing temperature can be from 40 ° C. to 70 ° C., and the processing time can be 10 minutes to 60 minutes. A as the processing solution
To d, and a dye-adsorbed head is manufactured using both the filling and the leaving treatment and the circulation treatment as the treatment method. Next, inks shown in Examples 1 to 6 and Comparative Examples 1 to 4 were prepared, and the printing characteristics described later were evaluated.

[0019]

Table 3 <Treatment liquid a> Dye I. Direct Black 154 1% Glycerin 10% Water * Remaining

[0020]

Table 4 <Treatment liquid b> Dye I. Acid Black 154 5% Ethylene glycol 95%

[0021]

Table 5 <Treatment liquid c> Dye C.I. I. Food black 2 2% Diethylene glycol 5% Glycerin 5% Water * Remaining

[0022]

Table 6 <Treatment solution d> Dye I. As the direct black 19 1% ethylene glycol 99% ink, the inks described in the following examples were used.

[0023]

<Example 1> Dye C.I. I. Direct Black 19 2% C.I. I. Direct Black 168 1% Solvent Glycerin 3% Ethanol 5% Water * Remaining

[0024]

<Example 8> Dye C.I. I. Direct Black 168 5% Solvent Diethylene glycol 10% n-Propanol 3% Water * Remaining

[0025]

<Example 3> Dye C.I. I. Food black 22% C.I. I. Direct Black 168 2% Solvent Ethylene glycol 5% Glycerin 2% Ethanol 5% Water * Remaining

[0026]

<Example 4> Pigment MA100 (manufactured by Mitsubishi Kasei Kogyo) 3% C.I. I. Direct Black 168 5% Solvent Triethylene glycol 4% Glycerin 3% Dispersant C.I. I. Direct Blue 86 0.5% Methanol 10% Water * Remaining

[0027]

<Example 5> Dye C.I. I. Direct Blue 86 3% C.I. I. Direct Black 168 0.05% Solvent Glycerin 4% n-Propanol 4% Water * Remaining

[0028]

Example 6 Dye C.I. I. Acid Red 254 2% C.I. I. Direct Black 168 0.1% Solvent Diethylene glycol 5% Ethanol 5% Water * Remaining

[0029]

<Comparative Example 1> Dye C.I. I. Food black 2 2% Solvent Diethylene glycol 5% Glycerin 5% Ethanol 5% Water * Remaining

[0030]

<Comparative Example 2> Pigment MA100 (manufactured by Mitsubishi Chemical Industry) 3% Solvent Diethylene glycol 3% Glycerin 5% Dispersant C.I. I. Direct Blue 86 0.5% Methanol 10% Water * Remaining

[0031]

<Comparative Example 3> Dye C.I. I. Direct Blue 86 3% C.I. I. Direct Black 168 0.03% Solvent Glycerin 5% n-Propanol 4% Water * Remaining

[0032]

<Comparative Example 4> Dye C.I. I. Direct Black 154 2% Solvent Diethylene glycol 10% Ethanol 5% Water * Remaining The following recording characteristics were evaluated using the inks described above.

Printing stability test Continuous printing is performed, and the total number of printing lines is divided by the number of missing dots during the printing to calculate the average number of printing lines. Judgment is made according to the following criteria based on the value.

[0034]

[Table 17] 10,000 lines or less × 10,000 to 30,000 lines △ 30,000 to 50,000 lines ○ 50,000 to ◎ Print recovery test In continuous printing, the recovery time in the event of troubles such as missing dots or printing disorder is measured. . The return operation is based on a method of sucking 5 ml of ink per minute from a head nozzle side by a pump. In order to evaluate the continuity of wettability by continuous printing, continuous printing is divided by the following number of lines, and the recovery time of trouble occurring in that range is averaged.

[0035]

[Equation 1] Average recovery time from 100,000 lines (second) Average recovery time from 100,000 lines to 300,000 lines (sec) Print quality (bending of flight) After continuous printing of 100 pages, wait for 30 seconds and wait again Make it print. The printing state at that time is checked, and the presence or absence of a flight bend is checked, and judgment is made according to the following judgment criteria.

[0036]

[Table 18] No bend ◎ Slightly bend △ Severely bend × Print quality (bleeding) Printing is performed on XeroxP (Fuji Xerox) to determine the presence or absence of bleeding, and to determine according to the following criteria.

[0037]

[Table 19] Clear printing without bleeding ◎ Bleeding is not a concern ○ Bleeding is a little worried △ Bleeding is severe × Head high temperature standing test Using our inkjet printer, HG-3000, perform a high temperature standing test under the following conditions. went.

Initially, after confirming that all nozzles eject, 4
Leave in 0 ℃ environment for 1 month. After standing, each nozzle was evaluated for printability. The difference in the effect of the ink on the deterioration of the bubble discharging property in the head by leaving the head at a high temperature was evaluated.

In the recovery operation, the HG-3000 is cleaned.

[0040]

[Table 20] No recovery even after recovery operation × Recovery is possible by recovery operation △ Printing is possible without recovery operation ○ Evaluation results of each ink are shown in Tables 21 and 22.

[0041]

[Table 21]

[0042]

[Table 22]

Tables 21 and 22 show that, in the ink jet recording method using a head in which the flow path substrate is made of plastic and a dye is previously adsorbed in the flow path, C.I. I. By using the ink containing Direct Black 168, the wettability obtained by the adsorption of the dye is maintained at an early stage, the flight bend is suppressed, and the discharge property of air bubbles can be satisfied. That is, printing stability, storage stability,
An ink having a good balance between water resistance and light resistance can be obtained.

[0044]

According to the present invention, it is possible to provide a highly reliable ink jet recording method capable of semipermanently maintaining the wettability of the dye adsorbed in advance. In addition, C.I. I. Since it is realized by using the dye of Direct Black 168, the printing stability is very good without bubbles such as a surfactant, and high printing quality can be realized without bleeding on paper. In addition, it is possible to omit the step of increasing the wettability by treating the surface of the plastic as in the past, and it is possible to make full use of the advantages of the plastic, which is low-cost and has high productivity.

[Brief description of the drawings]

FIG. 1 is a simplified explanatory diagram of the principle of ink droplet ejection in an inkjet recording method.

FIG. 2 is a simple explanatory view of a method of filling a processing liquid into a head flow path to adsorb a dye.

FIG. 3 is a simple explanatory view of a method of adsorbing a dye by circulating a processing liquid in a head channel.

[Brief description of reference numerals]

 2 Nozzle orifice 3 Cavity 10 Treatment liquid

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-1-263169 (JP, A) JP-A-59-182745 (JP, A) JP-A-4-339664 (JP, A) JP-A-4- 131245 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09D 11/00-11/20 B41J 2/01-2/21 B41M 5/00

Claims (3)

(57) [Claims] 1. An ink jet head in which a hydrophilic treatment liquid comprising a dye and water and / or a polyhydric alcohol is brought into contact with a plastic flow path base material to adsorb the dye to the flow path base material. I. An ink jet recording method using an ink containing Direct Black 168 in a range of 0.05% to 15%. 2. The method according to claim 1, wherein the hydrophilic treatment liquid is C.I. I. 2. The ink jet recording method according to claim 1, comprising direct black 154 and water and / or a polyhydric alcohol. 3. The ink further comprises 0.5% to 10% of a polyhydric alcohol selected from glycerin, ethylene glycol, diethylene glycol, triethylene glycol and propylene glycol, and is selected from methanol, ethanol and propanol. 1% monohydric alcohol
2. The ink jet recording method according to claim 1, wherein the content is from 10% to 10%.