The present invention relates to a printing apparatus in the form of a drop on demand (DOD) inkjet printer and a printing method in which a light-activated ink release system is utilized.
In the printing art inkjet printers are known which eject ink drops from an inkjet head toward a paper to print out desired information on the paper. In conventional inkjet printer arrangements, the ejection of ink drops can be implemented by various types of inkjet heads such as a magnetic on demand types or an on demand-type of head using an inorganic electro-restrictive element. Further, in conventional inkjet printer arrangements, light beams have been used as a measuring tool to measure properties of the ink.
U.S. Pat. No. 5,841,448, discloses an inkjet head arrangement in which an LED emits light onto a photodiode, then measurements as a result of the emission of the light are utilized for detecting an amount of ink, an ink density, etc.
U.S. Pat. No. 4,607,267 discloses the use of an electromagnetic wave to cause a certain component of ink to chemically react in a reaction chamber to generate a gas. The resulting pressure of the gas causes an inkjet drop to be ejected.
U.S. Pat. No. 4,611,486 discloses the use of a light source as a tool to measure and/or monitor a surface tension of a fluid.
Prior arrangements including the above-mentioned patents do not show or suggest the specific use of light-sensitive ink to create an ink droplet, as well as the concept of printing by aiming a light beam at an unextended ink droplet to cause an extension of the unextended ink droplet.
The present invention provides for an ink release mechanism for use in a DOD inkjet printer, in which a light-sensitive ink forms an extended ink droplet when a light beam is directed onto it.
With the apparatus and method of the present invention, it is possible to selectively aim a light beam at an array of nozzles having unextended ink droplets, so as to cause the unextended selected ink droplets to extend and permit the transfer of the ink to a receiver or media.
The present invention relates to a printing apparatus that comprises at least one nozzle. The at least one nozzle comprises a channel which has an ink body disposed therein that is comprised of light-sensitive ink. The channel of the at least one nozzle leads to a nozzle outlet such that an unextended droplet meniscus attached to the ink body is located at the nozzle outlet. The printing apparatus further comprises a light source that is adapted to direct a light beam to the unextended droplet meniscus to cause an extension of the unextended droplet meniscus, so as to form an extended droplet meniscus and permit ink to be transferred to a receiver which is disposed relative to the extended droplet meniscus.
The present invention further provides for a printing method that comprises the steps of forming unextended light-sensitive droplet menisci at outlets of a plurality of nozzles; impinging a light beam onto at least one of the unextended ink droplet menisci to form an extended droplet meniscus; and transferring ink from the extended droplet meniscus onto a receiver.
The present invention further provides for a printing apparatus that comprises at least one nozzle. The at least one nozzle includes a channel having an ink body disposed therein. The channel of the at least one nozzle leads to a nozzle outlet such that an ink droplet meniscus attached to the ink body is located at the nozzle outlet. The ink body comprises light sensitive ink having a surface tension which decreases when exposed to light so as to cause an outward extension of the ink droplet meniscus when exposed to light.
The present invention also relates to a method of assembling a printing apparatus which comprises the steps of: providing at least one nozzle on a printing apparatus having an ink holding area which leads to a nozzle outlet; providing light sensitive ink in the ink holding area such that an ink body is formed in the ink holding area and an unextended droplet meniscus attached to the ink body is located at the nozzle outlet; and providing a light source at a position relative to said unextended droplet meniscus to direct a light beam onto the unextended droplet meniscus, so as to cause an extension of the unextended droplet meniscus and form an extended droplet meniscus.