Inkjet printing

Inkjet printing is a type of computer printing that recreates a digital image by propelling droplets of ink onto paper and plastic substrates. Inkjet printers are the most used type of printer, range from small inexpensive consumer models to expensive professional machines; the concept of inkjet printing originated in the 20th century, the technology was first extensively developed in the early 1950s. The world first inkjet printer was invented by Ichiro Endo. In the late 1970s, inkjet printers that could reproduce digital images generated by computers were developed by Epson, Hewlett-Packard and Canon. In the worldwide consumer market, four manufacturers account for the majority of inkjet printer sales: Canon, HP, Epson and Brother; the emerging ink jet material deposition market uses inkjet technologies printheads using piezoelectric crystals, to deposit materials directly on substrates. The technology has been extended and the'ink' can now comprise solder paste in PCB assembly, or living cells, for creating biosensors and for tissue engineering.

Images produced on inkjet printers are sometimes sold under trade names such as Digigraph, Iris prints, Giclée, Cromalin. Inkjet-printed fine art reproductions are sold under such trade names to imply a higher quality product and avoid association with everyday printing. There are two main technologies in use in contemporary inkjet printers: continuous and drop-on-demand; the continuous inkjet method is used commercially for coding of products and packages. In 1867, Lord Kelvin patented the syphon recorder, which recorded telegraph signals as a continuous trace on paper using an ink jet nozzle deflected by a magnetic coil; the first commercial devices were introduced in 1951 by Siemens. In CIJ technology, a high-pressure pump directs liquid ink from a reservoir through a gunbody and a microscopic nozzle, creating a continuous stream of ink droplets via the Plateau-Rayleigh instability. A piezoelectric crystal creates an acoustic wave as it vibrates within the gunbody and causes the stream of liquid to break into droplets at regular intervals: 64,000 to 165,000 droplets per second may be achieved.

The ink droplets are subjected to an electrostatic field created by a charging electrode as they form. This results in a variable electrostatic charge on each droplet. Charged droplets are separated by one or more uncharged "guard droplets" to minimize electrostatic repulsion between neighbouring droplets; the charged droplets pass through another electrostatic field and are directed by electrostatic deflection plates to print on the receptor material, or allowed to continue on undeflected to a collection gutter for re-use. The more charged droplets are deflected to a greater degree. Only a small fraction of the droplets is used to the majority being recycled. CIJ is one of the oldest ink jet technologies in use and is mature; the major advantages are the high velocity of the ink droplets, which allows for a long distance between print head and substrate, the high drop ejection frequency, allowing for high speed printing. Another advantage is freedom from nozzle clogging as the jet is always in use, therefore allowing volatile solvents such as ketones and alcohols to be employed, giving the ink the ability to "bite" into the substrate and dry quickly.

The ink system requires active solvent regulation to counter solvent evaporation during the time of flight, from the venting process whereby air, drawn into the gutter along with the unused drops is vented from the reservoir. Viscosity is monitored and a solvent is added to counteract solvent loss. Drop-on-demand is divided into thermal DOD and piezoelectric DOD. Most consumer inkjet printers, including those from Canon, Hewlett-Packard, Lexmark, use the thermal inkjet process; the idea of using thermal excitation to move tiny drops of ink was developed independently by two groups at the same time: John Vaught and a team at Hewlett-Packard's Corvallis Division, Canon engineer Ichiro Endo. In 1977, Endo's team was trying to use the piezoelectric effect to move ink out of the nozzle but noticed that ink shot out of a syringe when it was accidentally heated with a soldering iron. Vaught's work started in late 1978 with a project to develop low-cost printing; the team at HP found. Two years the HP and Canon teams found out about each other's work.

In the thermal inkjet process, the print cartridges consist of a series of tiny chambers, each containing a heater, all of which are constructed by photolithography. To eject a droplet from each chamber, a pulse of current is passed through the heating element causing a rapid vaporization of the ink in the chamber and forming a bubble, which causes a large pressure increase, propelling a droplet of ink onto the paper; the ink's surface tension, as well as the condensation and resultant contraction of the vapor bubble, pulls a further charge of ink into the chamber through a narrow channel attached to an ink reservoir. The inks involved are water-based and use either pigments or dyes as the colorant; the inks must have a volatile component to form the vapor bubble. As no special materials are required, the print head is cheaper to produce than in other inkjet technologies. Most commercial and industrial inkjet printers and some con

Greg Manusky

Gregory Manusky is an American football coach and former linebacker of the National Football League. Manusky played in the NFL for three teams over twelve seasons. Manusky played college football at Colgate University and high school football at Dallas High School. Manusky was the linebackers coach for the Washington Redskins and San Diego Chargers before he became the defensive coordinator of the San Francisco 49ers in 2007. Following the 2010 season, 49ers head coach Mike Singletary was fired by the team. Former Stanford University head coach Jim Harbaugh replaced Singletary. Harbaugh gave Manusky permission to interview with other teams, Manusky lined up interviews with three teams: the Chargers, Arizona Cardinals and Dallas Cowboys. Manusky accepted the defensive coordinator job with the Chargers, with whom he had worked as a linebackers coach, he was fired following the 2011 season on January 5, 2012. The Indianapolis Colts hired Manusky as their defensive coordinator on February 2, 2012. After four seasons, he was fired by the Colts on January 5, 2016.

On January 22, 2016, Manusky was hired to be the outside linebackers coach for the Washington Redskins. A year the Redskins promoted him to defensive coordinator. After the 2019 season, the Redskins hired Ron Rivera as their new head coach. On January 2, 2020, the team announced that they would be parting ways with Manusky after Rivera hired Jack Del Rio to serve as his defensive coordinator. Greg Manusky and his wife, have four kids. Two sons and Jake, two daughters and Chandler. Washington Redskins bio


Wum is a town and commune in Cameroon. It is the capital of Menchum division in the Northwest Province. Wum is the third biggest town in the North West Region of Cameroon, it lies on a plateau at an elevation of about 1100 m near the edge of the western highlands of Cameroon. It is 80 kilometres north of the regional capital Bamenda, it lies near Lake Wum, one of five small crater lakes within 15 km of the town in the hilly, volcanic landscape. Lake Nyos, a crater lake from which a limnic eruption killed nearly 2000 people in 1986, is 25 km to the east. In 2012 Wum's estimated population was 80,123 inhabitants; the Aghem language, spoken in Wum, is called Wum. Charles Nanga, La réforme de l’administration territoriale au Cameroun à la lumière de la loi constitutionnelle n° 96/06 du 18 janvier 1996, Mémoire ENA. Contrôle de gestion et performance des services publics communaux des villes camerounaises - Thèse de Donation Avele, Université Montesquieu Bordeaux IV Site de la primature - Élections municipales 2002