Appeal No. 1997-3649 Page 8
Application No. 08/432,450
oxygen. The Examiner indicates that Fan discloses that the effect of atmospheric oxygen can be
overcome by longer radiation exposure times or higher intensity radiation sources. However, Fan also
indicates that the results are less reproducible when oxygen is present. One would not desire to form a
less reproducible printing plate when a barrier layer can be used which remedies that problem and other
problems too. The fact remains that Fan expressly requires a barrier layer in every embodiment of the
photosensitive element, there is no suggestion in Fan for eliminating the barrier layer, and Fan teaches
away from such elimination.
Next we turn to the Examiner’s alternative position that the barrier layer may itself be
photopolymerizable. We note that claim 1 requires the photopolymerizable layer not only contain
elastomeric binder, monomer and initiator, but it also requires that the monomer, or a plasticizer if
present, have a weight average molecular weight of 30,000 or less. In addition, we note that the
infrared sensitive layer of the claim is required to contain a binder which is incompatible or substantially
incompatible with the low molecular weight materials in the photopolymerizable layer.
In Fan, two types of barrier layers are described as useful. The first type is insensitive to actinic
radiation (col. 4, lines 54-55). The second type is photosensitive and is usually a layer of an
elastomeric composition (col. 5, lines 15-19). The elastomeric composition can consist simply of a
nonphotosensitive elastomeric binder layer similar to the binder in the photopolymerizable layer or it can
contain an elastomeric binder, monomer and initiator (col. 5, lines 19-23). Fan is silent as to the
Page: Previous 1 2 3 4 5 6 7 8 9 10 11 12 Next
Last modified: November 3, 2007