Oce-nederland B.v.

Oce-technologies B.v.

Cornelis W Venner

Franciscus H Tunnissen

Theodorus H Willems

Gerardus G Kessels

Ronald Fabel

Antonius H Habets

An image printing apparatus includes a number of image forming units for forming toner images of different colors in alignment on image receiving material in accordance with electronic image information signals fed to each image forming unit. Each image forming unit includes an image forming element rotatable about an axis of rotation and provided with a dielectric surface layer with adjacent electrode tracks in the direction of rotation. Each image forming unit further includes developing devices which include a linear developing magnet situated near the outer surface and parallel to the axis of rotation of the image forming element, toner feed devices for feeding a complete covering of electrically conductive and magnetically attractable toner powder to the image forming element, electrode track activating devices for applying a first or a second printing voltage between an electrode track and the magnet system in accordance with the image information signals to be fed to the image forming units. Toner powder on the passage of the electrode track along the developing magnet remains either on the image forming element or does not remain thereon in the event of a first or second printing voltage respectively on the electrode track. The image printing apparatus also includes at least one image forming unit provided with electronic image line correction devices for feeding image line correction signals to the electrode track activating devices in order to shift in time for each electrode track a printing period in which a printing voltage is applied to the electrode track in accordance with an image information signal.

Image printing apparatus

A raster image memory which serves as a bit-map memory for the storage of the bit representation of a whole page to be printed for a raster output scanner is connected to a raster image processor by a synchronous raster image bus having a number of data and modification code lines. Each memory element of the bit-map memory corresponds to a position on the page. The raster image processor fills the raster image memory. A logic processing unit is disposed between the raster image bus and the bit-map memory so that one input of the logic processing unit is connected to the data lines of the raster image bus and another input of the logic processing unit is connected to the data outputs of the bit-map memory. The logic processing unit is also capable of performing a number of logic operations on the data presented at the inputs of the logic processing unit in response to the signals on the modification code lines.

Raster image memory

The present invention is a front-end system for the conversion of graphical data and coded font data into a serial pixel-bit stream for a raster output scanner, such as a laser printer. The front-end system includes a front-end controller, input/output means, which can be connected to a computer or a data network, and a memory for storing graphical data and coded font datat. Final printing format is determined by a fine formatter. The present front-end system also includes a bitmap memory for storing a bitmap representation of the page to be printed, a bitmap filler for expanding the data and placing them into the bitmap memory, and a bitmap reader. The functions of the front-end controller and of the input/output means are implemented in a first processor and the functions of the fine formatter and the bitmap filler are implemented in a second processor. The bitmap reader is formed by dedicated hardware logic. With the present construction, a high speed page processing can be achieved with a reduced number of processors.

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Meijel, Netherlands

Cornelis W Venner