37 CFR 1.4 Nature of correspondence and signature requirements.
- (b) Since each file must be complete in itself, a separate copy of every paper to be filed in a patent, patent file, or other proceeding must be furnished for each file to which the paper pertains, even though the contents of the papers filed in two or more files may be identical. The filing of duplicate copies of correspondence in the file of an application, patent, or other proceeding should be avoided, except in situations in which the Office requires the filing of duplicate copies. The Office may dispose of duplicate copies of correspondence in the file of an application, patent, or other proceeding.
When the Office does not require duplicate copies of a paper, the filing of multiple copies may cause a delay in processing by the Office. Accordingly, the Office may discard duplicate copies of correspondence filed in an application or patent file.