legal ground
Article 120 of the Detailed Rules for the Implementation of the Patent Law of People's Republic of China (PRC)
When mailing documents related to the application or patent right to the patent administration department of the State Council, registered letters shall be used, and parcels shall not be used.
In addition to submitting the patent application documents for the first time, when submitting various documents and going through various formalities to the patent administration department of the State Council, the application number or patent number, the name of the invention-creation and the name of the applicant or patentee shall be indicated.
Article 12 1
All kinds of application documents shall be typed or printed in black, with neat and clear handwriting and shall not be altered. The attached drawings shall be drawn with drawing tools and black ink, and the lines shall be uniform and clear, and shall not be altered.
The request, specification, claims, drawings and abstract shall be numbered in Arabic numerals respectively.
The text of the application documents shall be written horizontally. Paper is confined to one side.