Copier-Duplicator

an assembly that makes multiple copies of pictorial material, used in the printing and publishing industry for preparing printing forms with a repeating image, mainly for planographic (offset) printing. Copier-duplicators are capable of producing completely identical copies. This fact is particularly important for color-set forms.

Picture reproduction by copier-duplicator is one of the photo mechanical methods of producing printing forms. The image obtained from a negative or a diapositive is copied several times onto a form plate covered by a light-sensitive layer.

The plate is laid on a bed above which there is a carriage supporting a light source (an arc light or a concentrating lamp) and a frame holding the material to be copied. Upon exposure, the frame with the original is pressed tightly against the form plate by a hydraulic or pneumatic device. The surface of the plate, with the exception of the area to be exposed, is automatically covered by a shutter. The light source is then switched on.

Exposure time and light are controlled by an exposure meter. After completing the first step, the bed is lowered, the carriage is moved to the next area of the plate, and the second operation begins.

The bed and carriages are moved manually; two handwheels control vertical and horizontal motion. The images on the form plate are positioned precisely by setting the frame and carriage against graduated scales and an indicator (according to previous calculations).

In automatic copier-duplicators, all movement, light switching, and light metering operate according to a program built into the control equipment. Copier-duplicators can have either horizontally or vertically arranged plates and mounting frames. Copier-duplicators lower the volume of photographic work and retouching, reduce the consumption of photographic materials, and assure a high degree of accuracy in preparing large-format print forms.