Chokes for microwave dryers that block microwave energy and enhance thermal radiation

#The invention relates to the field of dryers, and in particular, to continuous-process microwave dryers.

#Production printing systems for high-volume printing typically utilize a production printer that marks a continuous-forms print medium (e.g., paper) with a wet colorant (e.g., an aqueous ink). After marking the continuous-forms print medium, a dryer downstream from the production printer is used to dry the colorant applied to the continuous-forms print medium. Microwave dryers may be employed as a dryer for a production printing system in some applications.

#A microwave dryer utilizes microwave energy to heat the colorant to cause a liquid portion of the colorant to evaporate, thereby fixing the colorant to the continuous-forms print medium. A microwave source directs the microwave energy down a long axis of a waveguide, and a passageway through the waveguide is sized to enable the continuous-forms print medium to pass through the waveguide. As the continuous-forms print medium traverses the passageway, wet colorant applied to the continuous-forms print medium is exposed to the microwave energy and is heated.

#Some embodiments of the present invention are now described, by way of example only, and with reference to the accompanying drawings. The same reference number represents the same element or the same type of element on all drawings.

#FIG. 1 is a block diagram of a printing system in an illustrative embodiment.

#FIG. 2 is a side view of a choke assembly for a microwave dryer in an illustrative embodiment.

#The figures and the following description illustrate specific illustrative embodiments of the invention. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described or shown herein, embody the principles of the invention and are included within the scope of the invention. Furthermore, any examples described herein are intended to aid in understanding the principles of the invention, and are to be construed as being without limitation to such specifically recited examples and conditions. As a result, the invention is not limited to the specific embodiments or examples described below, but by the claims and their equivalents.

#FIG. 1 is a block diagram of a printing system 100 in an exemplary embodiment. Printing system 100 comprises any system capable of marking print media (or other objects) and performing microwave drying as part of a continuous process. In this embodiment, printing system 100 includes printer 110, microwave dryer 120, and planar substrate 130 (e.g., a continuous-forms print medium, a continuous transport belt bearing cut-sheet print media, etc.). Planar substrate 130 travels along process direction 150 in FIG. 1 to receive marking at printer 110 and drying at microwave dryer 120.

#Print controller 112 of printer 110 receives print data 116 which defines locations at which to mark underlying print media. Print data 116 may be defined according to a Page Description Language (PDL), such as Portable Document Format (PDF). Print data 116 is rasterized by print controller 112 into bitmap data. The bitmap data is used by marking engine 114 (e.g., a drop-on-demand print engine) of printer 110 to apply wet colorant as planar substrate 130 travels downstream towards microwave dryer 120. In embodiments where planar substrate 130 is a continuous-forms print medium, planar substrate 130 is marked by marking engine 114 of printer 110. In embodiments where planar substrate 130 comprises a continuous transport belt, items being carried by planar substrate 130 (e.g., cut-sheet print media) are marked by marking engine 114 of printer 110. Some examples of print media include paper and textiles. Marking engine 114 may apply a wet or liquid colorant, such as one or more aqueous inks. Thus, printer 110 may comprise a continuous-forms inkjet printer, a cut-sheet inkjet printer, etc. Print controller 112 may be implemented as custom circuitry, as a hardware processor executing programmed instructions, etc.