JPH04169269A - Ink redispersion method and ink cartridge in inkjet printing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an inkjet printing method for recording characters and images using liquid ink.

[Prior Art] Traditionally, water-based inks have been the mainstream recording ink used in inkjet printing devices due to odor, safety, etc., and various water-soluble dyes have been mixed with water or with water. Dissolved inks that are dissolved in a mixed solvent and various additives added as necessary are currently in use, but pigment-based inks and emulsion-containing inks are preferred in terms of print quality, print density, water resistance, light resistance, etc. The use of dispersion inks such as resin-colored emulsion inks in which resin is impregnated with dyes is expected.

[Lesson 11 that the invention attempts to solve! ] However, with the above-mentioned conventional technology, (1) the nozzle and the ink flow path are easily clogged;

(2) Separation, aggregation, and sedimentation occur during storage.

There are reliability issues such as

Therefore, the present invention aims to solve these problems.
An object of the present invention is to provide a reliable inkjet printing method that has high print quality, high print density, excellent water resistance and light resistance, is free from clogging, and has good storage stability.

[Means for Solving the Problems] The inkjet printing device of the present invention is characterized in that, in an inkjet printing method for recording characters and images using liquid ink, the recording ink used in the inkjet printing device is redispersed.

[Example] The inkjet printing method of the present invention will be specifically illustrated below.

As the redispersion means used in the present invention, a means for redistributing the recording ink at the same time as the carriage moves by placing an ink cartridge directly on the head carriage can be applied. It is also more effective to insert balls or beads into the ink cartridge and redisperse the ink in order to increase the collision energy and shear stress between particles.

Further, the ink in the ink cartridge can be redispersed by periodically stirring the inside of the ink cartridge using a magnetic stirrer or the like, or by using ultrasonic dispersion using an ultrasonic vibrator, centrifugal force, or the like.

(Example 1) Using dispersed inks of water-based pigment ink, non-aqueous pigment ink, water-based emulsion ink, and non-aqueous emulsion ink, an ink cartridge was placed on the carriage, and redispersion was performed at the same time as printing. For various transfer materials such as paper, PPC paper, recycled paper, and general HP paper,
Text, graphics, etc. were printed.

(Example 2) Using the ink used in Example 1, a mechanism for stirring the inside of the ink cartridge with a magnetic stirrer was provided, redispersion was performed periodically, and printing was performed in the same manner as in Example 1.

(Example 3) Using the ink used in Example 1, the inside of the ink cartridge was subjected to ultrasonic waves to periodically perform redispersion, and printing was performed in the same manner as in Example 1.

(Comparative Example) Using the ink used in Example 1, printing was performed by supplying the ink to the head using a pump without placing the ink cartridge on the carriage.

In addition, the evaluation pattern in the example is 180DP (
A commercially available on-demand inkjet printer (dots/inch) equipped with a redispersion means and a plurality of nozzles 2 are provided on a nozzle forming substrate 1 shown in FIG. A piezoelectric transducer 5 made of a laminated material No. 4 is placed nearby, and a head having a structure immersed in ink 6 is used to displace the piezoelectric transducer 5 by applying a voltage 7 to pressurize the ink inside the nozzle forming substrate. Te nozzle 2
A prototype inkjet printer (resolution: 300 DPI) that prints by ejecting the ink from the ink was equipped with a redispersion means. No difference was observed between the results between the two devices.

Furthermore, the piezoelectric transducer used was one that had been subjected to insulation treatment.

The following evaluations were made for the Examples and Comparative Examples.

The evaluation method is described below.

1. Bleeding evaluation Observation with a microscope at 100x and 400x and visual observation O: Dots are retained on the fibers without any bleeding along the fibers O: There is some bleeding along the fibers, but it cannot be seen visually. △: Slight bleeding visible by visual inspection ×: Significant bleeding and jagged edges 2. Clogging evaluation Fill ink into an inkjet printing device and hold at 50°C.
Cap and leave in an environment of , installed in an inkjet printing device and check the ejection stability ■: Ejection is stabilized by redispersion O: Sedimentation is seen but redispersion is easy and ejection is stable X: No ejection 4, Recording density Macbeth Measurement of reflection ○/D value with thermometer 5, Water resistance evaluation After 1 hour of printing, soak the printed matter in water for 5 minutes and observe ink flow O: None ×: Yes 6, Light resistance evaluation Irradiated with xenon lamp for 100 hours Table 1 shows the evaluation results of blue scale fading: less than 250% ×: 50% or more.

As is clear from Table 1, the recording inks of Examples 1 to 3 were extremely superior to the comparative examples in terms of print quality (bleeding, temperature, water resistance/light resistance), clogging resistance, and ink storage stability. The results were obtained.

[*Effect of brightness] As explained above, according to the inkjet printing method of the present invention, by redispersing the recording ink, the ejection characteristics are stabilized, and it is possible to print on any transfer material without bleeding and with high quality. It has the effect of enabling clear recording of temperature.

[Brief explanation of the drawing]

1st f! I is a sectional view of a head for explaining the inkjet structure and the principle of ejecting ink droplets in the present invention. 1... Nozzle forming substrate 2... Nozzle 3... Piezoelectric element 4... Metal plate 5... Piezoelectric transducer 6... Ink 7... Power supply and more Applicant: Agent for Seiko Epson Corporation Patent attorney Kizobe Suzuki (1 person) Figure 1

Claims (1)

[Claims] An inkjet printing method for recording characters and images using liquid ink, the method comprising redispersing the recording ink used in the inkjet printing device.