The proceeds of bona fide infringers are not unjust enrichment and need not be returned.
However, if the seller still sells the infringing products in his inventory after being notified by the patentee, it cannot be considered that he is unaware of it. China's patent law specifically defines this situation as "for the purpose of production and operation, using or selling a product that is not known to be patented and manufactured or sold without the permission of the patentee or a product directly obtained according to the patented method can prove the legal source of the product". Here, the scope of behavior is limited to use and sale. For manufacturing or importing, according to the current law, the actor should or has the obligation to know whether the products he manufactures or imports are patented products. Legally speaking, the relevant procedures of patent announcement provide a way to know the patent status. When manufacturing or importing a product, the manufacturer concerned should know the status of the product in the patent law. Although the Patent Law also has special provisions on the use or sale of infringing products without knowledge, it does not think that this kind of behavior is not infringement, but it does not bear tort liability for the behavior it did during its ignorance.