Print head for on-demand ink jet printer

Abstract

The invention relates to a print head for an on-demand ink jet printer. The internal of the print head is divided into a cavity and a cartridge via a movable valve, heat conductive gas and ink are injected into the cavity and the cartridge respectively, an electric hot plate at one side of the cavity starts heating after receiving an electric signal from the printer, a heat conductive metal blockand the heat conductive gas are thermally expanded to push the movable valve to move towards the cartridge, and ink is extruded and injected out; and when printing is completed, the electric hot platestops heating, the heat conductive metal block and the heat conductive gas are contracted, and the movable valve moves towards the cavity to stop ink jetting. An ink inlet valve is provided with an inductor; in the process that an ink drop is formed and injected, namely when the electric hot plate is heated, the valve is closed automatically, and when the ink drop is sprayed, namely the electrichot plate stops heating, the valve is opened automatically, and ink is input. The print head of the invention is simple in structure, spray-out and stop of the ink are controlled by fully utilizing apressure generated by expansion with heat and contraction with cold, and the production cost is lower.

Description

technical field [0001] The invention belongs to the technical field of printing, and in particular relates to a printing head for a drop-on-demand inkjet printer. Background technique [0002] Inkjet printers can be used in different fields such as office, commerce, and industry. Especially, the color reproduction effect of industrial inkjet printers can be comparable to that of offset printing, because it can meet the individual needs of customers, and has the characteristics of printing from one sheet, fast and efficient, and the development of fast. [0003] At present, inkjet printing technology can be divided into continuous inkjet and drop-on-demand inkjet according to the continuity of ink droplets. Common inkjet methods in drop-on-demand inkjet include thermal inkjet, piezoelectric inkjet, and electrostatic inkjet. Among them, piezoelectric inkjet technology is relatively mature, but piezoelectric crystals are more expensive, resulting in higher cost of the correspo...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to solve the problems existing in the existing drop-on-demand inkjet printing technology, such as high cost of piezoelectric crystals, difficulty in controlling air bubbles, and easily disturbed electrostatic inkjet effects, and provide a new type of drop-on-demand inkjet print head. The print head utilizes the principle of thermal expansion and contraction, and pushes the ink in the ink tank to be discharged through the metal and gas medium with good thermal conductivity, so as to realize the printing of various patterns

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