Incremental printing of symbolic information – Ink jet – Ejector mechanism
Patent
1995-09-11
1998-03-31
Malley, Daniel P.
Incremental printing of symbolic information
Ink jet
Ejector mechanism
347 59, 437 51, B41J 205
Patent
active
057343950
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ink jet head that is the main component of an ink jet recording apparatus, and relates particularly to a compact, high density ink jet head using electrostatic power as the drive power therefor.
2. Description of the Related Art
Ink jet recording apparatuses offer numerous benefits, including extremely quiet operation during recording, a high speed printing capability, and the ability to use low-cost plain paper. The so-called "ink-on-demand" drive method whereby ink is output only when required for recording is now the mainstream in such recording apparatuses because it is not necessary to recover ink not used for recording.
The ink jet heads used in this ink-on-demand method commonly use a piezoelectric device for the drive means as described in JP-B-51734/1990, or eject the ink by means of pressure generated by heating the ink to generate bubbles as described in JP-B-59911/1986; it is primarily these two methods that are practical today, and are used in many ink jet printers.
However, in the former method using a piezoelectric device, the process of bonding the piezoelectric chip to the diaphragms used to produce pressure in the pressure chamber is complicated. With current ink jet recording apparatuses having plural nozzles and a high nozzle density to meet the demand for high speed, high quality printing, these piezoelectric devices must be precisely manufactured and bonded to the diaphragms, processes that are extremely complicated. As the nozzle density has increased, it has become necessary to process the piezoelectric devices to a width of several ten to one hundred and several ten microns. With the dimensional and shape precision achievable using current machining processes, however, the ejection characteristics of the nozzles is inconsistent and there is a wide variation in print quality; this method is particularly unsuitable as a means of providing a high density ink jet head at low cost.
In the latter method in which the ink is heated, the above problems do not exist because the drive means is formed by means of a thin-film resistive heater. The resistive heater does become damaged over time, however, by the repeated rapid heating and cooling of the drive means and the impact of bubble dissipation, and the practical service life of the ink jet head is accordingly short.
As another effective drive means solving these problems, an ink jet head using electrostatic force as the drive power has been proposed in U.S. Pat. No. 4,520,375 and JP-A-289351/1990; in this ink jet head, a silicon (Si) substrate is etched; a diaphragm and pressure chamber are integrally formed on the silicon substrate; a conductive substrate is formed in opposition to the back of the pressure chamber with a gap therebetween; the gap between the diaphragm and conductive substrate is repeatedly charged and discharged to produce an electrostatic force therein that causes the diaphragm to vibrate; and ink is thus ejected from the nozzle by the pressure change produced in the pressure chamber. These methods using electrostatic force as the drive power have at present not reached the point of practical application as an actuator for ink jet printers, but with recent advances in micromachining techniques have gained significant reliability as micropumps implanted in the body for the administration of drugs (insulin); when applied as an actuator for an ink jet printer to take advantage of such features as the precise, simple construction and long-term reliability, benefits such as a compact, high density package and long service life will be obtained.
However, if a method using electrostatic force as the drive power is to be applied as the actuator of an ink jet printer, it must be possible to drive the actuator at the power supply voltage commonly used for printers, i.e., information devices, and it must be possible to achieve high speed printing, i.e., operation driven by a high frequency must be possible; U.S. Pat. No. 4,520,375 and JP-A-2
REFERENCES:
patent: 5081474 (1992-01-01), Shibata et al.
patent: 5534900 (1996-07-01), Ohno et al.
Atobe Mitsuro
Fujii Masahiro
Kamisuki Shinichi
Kobayashi Naoki
Koeda Hiroshi
Malley Daniel P.
Seiko Epson Corporation
Watson Mark P.
LandOfFree
Ink jet head does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Ink jet head, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ink jet head will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-55551