Patent Application
20100021220
The present disclosure relates to photo printing or copying on sheet print media where the sheets are fed from a stack into a printer or photocopier for marking. In service, it has been found that during periods of operation of such devices in high humidity climatic conditions, the sheet print media and particularly sheet paper stock is subject to excessive curling which results in paper jams upon entering the feeder. In particular, in regions where the humidity is 80% or higher, paper curling occurs quite often and significantly reduces the productivity of the printing due to machine jamming from paper mis-feed.
Heretofore, attempts have been made to reduce the curling of the sheet paper stock in high moisture conditions by providing a heater under the stack of paper, drying the paper by natural convection to thereby reduce the curling and jamming. Such attempts involved installing line voltage ceramic block mounted heating elements in the machine compartments immediately beneath the sheet paper stack to provide heated air for drying the paper. These block heaters provided an electrical shock hazard by virtue of their line voltage connections and thus required costly shielding and safety devices to prevent user shock, shorting and over-heating. Furthermore, the installation of the block heaters and the wiring interconnections necessary to effect their operation has been found to be costly and time consuming where retrofitted to existing photocopiers. Thus, it has been desired to provide a less costly, efficient and electrically safer way of drying the sheet paper stack in a printer/photocopier and which is simple and easy to install in the machine.
The present disclosure describes a low-voltage flexible pad-like heater or heating pad which may be disposed in the bottom of the cabinet for a sheet paper stacker/feeder for convective drying of the sheet stock in the stack and which is simple and easy to install. The heating pad disclosed herein is of the type employing a resistance wire heating element embedded in silicon rubber which has resistance to elevated temperatures and provides excellent electrical insulating properties. The air surface heating pad of the present disclosure operates at a maximum continuous heating temperature of 200° C. and can withstand over temperature excursions as high as 230° C. The pad is thin and lightweight with a low thermal mass thus providing rapid heat-up and relatively quick response to temperature controlling. The pad may be molded to the configuration of the bottom of the cabinet to provide simple installation yet optimize the amount of heating element present for the cabinet configuration. The heating pad may be manufactured with a self-adhesive backing to allow for ease of installation in the cabinet of the stacker/feeder.
Referring to
Referring to
Referring to
The flexible heater pad of the present disclosure is thus readily installable in the base of a sheet stacker/feeder by virtue of the adhesive backing and provides protection from electrical shock by operating only on low voltage power supply. The sheet paper in the stacker/feeder may thus be maintained in a desired state of dryness by natural convection of the air rising from the heater pad.
It will be appreciated that various of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Also that various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.
