electrophotographic


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electrophotographic

The printing technique used in laser and LED printers and most copy machines. It uses electrostatic charges, dry ink (toner) and light. A selenium-coated, photoconductive drum is positively charged. Using a laser or LEDs, a negative of the image is beamed onto the drum, cancelling the charge and leaving a positively charged replica of the original image.

A negatively charged toner is attracted to the positive image on the drum, and the toner is then attracted to the paper, also positively charged. The final stage is fusing, which uses heat and pressure, pressure alone or light to cause the toner to permanently adhere to the paper.

Xerography Was Introduced in 1948
In 1938, electrophotography was invented by Chester Carlson in Queens, New York, and his first of 28 patents was issued in 1940. By 1947, Haloid Corporation and Batelle Development Corporation were working with Carlson, and xerography became official in 1948. A huge breakthrough, it replaced the messy liquid ink of the duplicating machines of the day with a dry, granular ink. In Greek, xero means "dry," and graphy means "write."


Electrophotographic Process
Electrostatic charges are used to create a charged light image on the drum. The toner is attracted to the drum and then to the paper.







"Painting" the Drum
The laser printer uses a single light directed by moving mirrors, but there are more lenses and parts than are shown here. The LED printer has a stationary array of thousands of tiny LEDs that are selectively beamed onto the drum.







The Model A - 1949
The first Xerox copier was manually operated, but it provided the experience and revenue to develop the automatic, floor-standing Xerox 914 ten years later. The 914 was a huge success. (Image courtesy of Xerox Corporation.)







The 1938 Experiment Replicated in 1965
With india ink, Carlson wrote "10-22-38 ASTORIA" on a glass slide and rubbed a sulphur-covered zinc plate with a handkerchief to apply an electrostatic charge. He put the slide on the plate, exposed it to light with the room dark, removed the slide and sprinkled lycopodium powder on the plate. He gently blew off the loose powder, and what remained was the first electrophotographic copy. After Xerox became successful, Carlson was showered with honors and wealth. At age 62 in 1968, he died of a stroke on a New York street. (Image courtesy of Xerox Corporation.)
References in periodicals archive ?
- and peeling (47) the emboss hologram transferring member (20) from the electrophotographic image (10H, W), whereby the corrugation profile of the emboss hologram transferring member is transferred onto the electrophotographic image area.
For creating the experimental samples the developing system of the electrophotographic printing machine HP Indigo TurboStream was used and 135 g/[m.sup.2] glossy fine art paper was used as the printing substrate.
The non-impact print engine uses an electrophotographic process and features 8 ppm performance and monthly duty cycles of up to 5,000 pages at 300 x 300 dpi.
Such type of the writing head was built in the first electrophotographic machines of the type HP Indigo series 1000, which were replaced by greater and quicker models of the series 5000.
The results justify the creation of statistic models including multifactorial analysis and the determination of the essential conditions in different phases of the indirect electrophotographic printing (voltage of scorotrone, laser strength, voltage of the offset cylinder, concentration of the liquid toner etc.) which leads to the optimization of the deinking flotation process and to obtaining fibres with better characteristics.
Our research is based on the most complex electrophotographic model, Xeikon DCP32D, whose functioning has been tracked and stored in the database during 12 years.
A big leap into the digital segment was taken by Flint Group, when it announced late last year the acquisition of a majority shareholding in Xeikon, the Netherland-based manufacturer of electrophotographic presses mainly for labels and packaging applications, but also for document and commercial printing.
A new report from market research firm Technavio forecasts the global electrophotographic printing market in the packaging industry to grow at a CAGR of 8.78% over the period 2014-2019.
Commonly used imaging method in electrophotographic printing process is DAD (discharged area development) method where the photoconductor surface is exposed to prior defined electromagnetic wavelength (energy) which causes local photoelectric effect in CGL (Charge Generation Layer) layer.
HP Indigo and Xeikon are still making headlines with their advancements in electrophotographic (EP) technology.