Improved head and UV lamp layout

US 2012/0287214 A1
Image forming apparatus
Seiko Epson Corporation

One of the problems with printers using UV-curable inks is that the curing systems must be placed relatively close to the printheads.  However if stray UV-light reaches the ink in the nozzles it can cure the ink at the meniscus and stop the printhead from working.  Most of the light that can reach the printhead is reflected from the substrate, so the standard technique is to space the printhead and curing system as far apart as is practical and insert an optical trap in between.  An optical trap is normally a component with multiple walls painted black to intersect and absorb as much light as possible.

Nov12

The solution here is to angle both the lamps and printheads towards the paper feed directions as shown in the figure.  This reduces the reflected light and removes the need for the optical traps.  This enables the printheads to be mounted closer together.  When printing and curing multiple colours, the closer together the printheads are together the better the registration between colours is likely to be.