Abstract: An electrostatographic single-pass multiple station multi-colour printer for forming an image onto a web. The printer has a plurality of toner image-printing electrostatographic stations. Each station has a drum onto the surface of which a toner image can be formed. An exposure station forms an electrostatic toner image line-wise on each drum surface. A corona device transfers the toner image onto the web, which is conveyed in succession past the stations in synchronism with the rotation of the drum surface. A register control device is provided for controlling the operation of each of the stations in timed relationship thereby to obtain correct registering of the distinct toner images on the web. The register control device includes an encoder driven by the displacement of the web to produce pulses indicative of web displacement, and delay system arranged to initiate the operation of subsequent stations after a predetermined web displacement, as measured by the encoder, has occurred.

Abstract: An electrophotographic printer includes a plurality of recording heads connected in series in a closed cooling circuit. Each of the recording heads includes a linear array of light-emitting diodes (LEDs) on a common thermally conductive LED carrier bar. The carrier bar carries a series of modules, each module containing N LEDs with their associated drivers. The carrier bar is provided with a U-shaped duct inside a thermally conductive body which is in thermally conductive contact with the carrier bar. The duct extends between a fluid inlet and a fluid outlet and has a cooling fluid such as water flowing therethrough.

Abstract: An electrostatographic printer for forming an image onto a web comprises at least one toner image-producing electrostatographic station having a drum onto which a toner image can be formed, a transport for conveying a web past the image-producing station, apparatus for controlling the speed and tension of the web while it is running past the image-producing station, and transfer apparatus for transferring the toner image on the drum onto the web. The printer is characterized by a control arrangement for switching between a printing mode wherein a printing web moves in synchronism with the peripheral speed of the drum and a refurbishment mode wherein a refurbishment web moves at a faster speed relative to the peripheral speed of the drum and in contact therewith, to cause refurbishment of the drum surface.

Abstract: A method of forming a drum assembly for use as a rotatable endless surface onto which a toner image is formed. The drum assembly has a hollow drum with an opening at each end and a surface onto which the image is formed. A support flange, having an aperture in the center thereof, is cooled before being inserted into each end opening. The drum assembly also includes a shaft having a collar fixed in the vicinity of each end. After the shaft is positioned inside the drum, the collars are positioned to coincide with the flange apertures. Screws secure each collar to its respective flange. The screws can be adjusted to reduce the eccentricity of the drum.

Abstract: A non-impact printer is described for forming an image on a medium. The printer having:a linear array of recording sources for forming a multi-gradation latent image on a receptor surface, the linear array comprising a plurality of sub-sets of recording sources;an element for developing the latent image into a visual image;an element for transferring said visual image onto the medium;an element for generating and storing first correction factors derived from measurements of the non-uniformity of average energy output of each of the sub-sets of recording sources;first correction element for applying, for each sub-set of recording sources, the first correction factors;an element for generating and storing second correction factors derived from measurements of the non-uniformity of each individual one of the recording sources; andsecond correction element for applying said second correction factors after applying the first correction factors.