Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2002-02-08
2003-10-28
Nguyen, Lamson (Department: 2861)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06637862
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to fluid jet devices. More particularly, the present invention pertains to fluid jet devices, such as ink jet print systems and maintenance modules configured for mounting to an ink jet print system print head.
Fluid jet devices are in wide spread use. One particular use for such a device is in ink jet printers. There are a number of principle types of ink jet printers. One type of printer relies upon capillary action to move a working fluid (e.g., ink) to the print head. The ink is directed from the print head through one or more orifices toward a target substrate. Ink jet printers include an actuator for urging the ink through the orifice. Actuators can include piezzo electric elements, thermal devices and the like. An exemplary ink jet print head is disclosed in DeYoung et al., U.S. Pat. No. 4,418,355.
Typically, the print head includes a fluid passageway or chamber configured for ink flow from a source to the actuator, and through the orifices. During normal operation of the print head, ink is present in the passageway or chamber. Actuation of the actuator draws ink into the passageway through the actuator and out through the orifices. It has, however, been found that air, which can enter the fluid chamber (through the orifices) or dirt or debris that can become lodged in the orifices, results in improper operation of the fluid jet device. Air and debris can result in reduced ink drawn into the flow passageway and subsequently cause the failure to eject ink through the orifices. Thus, it has been found that for effective operation of the print head, the ink flow passageway or chamber must be devoid of air and dirt or debris and that the passageway must remain filled with ink.
A number of devices, configurations and methods have been proposed and are used to prevent improper operation of the print head either by preventing air entrainment in the ink or by preventing debris from gathering at the orifices. Some of these configurations and methods are directed to preventing the entrainment of air and collection of debris, while other configurations and methods are directed to mitigating the effects of air entrainment and debris. Still others are directed to removing air that may have already been entrained in the system, or by removing debris that may have already collected at the orifices.
It has, however, been found that many such “maintenance” designs require complex arrangements of plates, fluid (e.g., air) supplies, vacuum lines and the like external to the print head. Although many of these configurations and methods have been found to be effective, their complexity increases the cost of the overall system, as well as the opportunity for equipment failure because of design and component complexity.
Accordingly, there exists a need for a maintenance module for a fluid jet device having a straight-forward and simple design. Most desirably, such a maintenance module facilitates the collection of purge fluid from the fluid jet device used to entrained air and debris that may have collected on the jet device. Most desirably, such a maintenance module incorporates provisions for drawing a vacuum at the fluid jet device to remove fluid that may have been ejected from the device during the purge cycle.
BRIEF SUMMARY OF THE INVENTION
A maintenance module is mounted to the front of a fluid jet device to facilitate maintaining the front of the device in a clean state. The module includes first and second plates affixed to one another. The plates define a longitudinal axis and a transverse axis perpendicular to the longitudinal axis.
The first or rear plate is a chamber plate/orifice plate that overlies the fluid chamber of the fluid jet device. The first plate has a plurality of orifices formed therein. In a present embodiment, the first plate has to parallel rows of closely spaced orifices. The orifices extend parallel to the longitudinal axis inwardly of longitudinal edges of the plate.
The first plate includes a vacuum opening formed therein at about a transverse edge of the first plate. The vacuum opening is preferably formed along the longitudinal axis and extends into the plate, perpendicular to a plane defined by the longitudinal and transverse axes. In a current embodiment, the vacuum opening has inwardly tapered walls.
To mount the module to the fluid jet device, the first plate can include a plurality of mounting openings extending along opposing longitudinal edges of the plate inwardly of the edges. The mounting openings are formed parallel to the longitudinal axis and spaced outwardly of the orifices. The first plate can include a flange extending about a periphery thereof.
The second plate is affixed to and preferably bonded to the first plate. The second plate has an elongated channel therein extending over the first plate orifices so that the orifices are exposed through the elongated channel. The channel is defined by opposing longitudinal edges extending parallel to the longitudinal axis and preferably formed symmetrically about the longitudinal axis.
The channel has tapered edges at about an end thereof. The tapered edges converge to an arcuate funneling region. The second plate overlies the first plate such that the funneling region extends along an edge of the vacuum opening. In a current embodiment, the second plate includes a plurality of fastener openings that correspond to an d align over the first plate mounting openings.
To facilitate properly aligning the module on the fluid jet device, the maintenance module can include orienting notches formed in the first and second plates that align with one another. In a present embodiment, orienting notch is formed through the first plate up to but exclusive of the flange.
The maintenance module can be formed with the second plate having a polymer coating thereon. The coating facilitates maintaining the plate in a clean condition.
These and other features and advantages of the present invention will be apparent from the following detailed description, in conjunction with the appended claims.
REFERENCES:
patent: 4284993 (1981-08-01), Kakeno
patent: 4827287 (1989-05-01), Braun et al.
patent: 6347859 (2002-02-01), Kawakami et al.
Cahill Clifford J.
Duong Ha V.
Ky Bopta
Breh Donald J.
Croll Mark W.
Feggins K.
Illinois Tool Works Inc.
Nguyen Lamson
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