Can the original patentee still use it after the patent transfer fee is paid?

No, the transfer of rights and interests can be free. For the patent transfer contract, if the transferor transfers the patent right, the patent right will be lost. Therefore, after the transfer, the original obligee can no longer use the patent unless it is stipulated in the contract or agreed by the licensor. The transferee, the new obligee, can use it for free. The transfer of patent right means that the patentee transfers the obtained patent ownership to others. Lawyers should pay attention to the fact that the transfer of patent rights must comply with the law and go through the transfer procedures according to law. Where a unit or individual in China transfers a patent right to a foreigner, it must be approved by the relevant department in the State Council. When assigning the patent right, the client must conclude a written contract, which will take effect after being registered and announced by the Patent Office. Lawyers should pay attention to the fact that the transfer of patent rights must comply with the law and go through the transfer procedures according to law. Where a unit or individual in China transfers a patent right to a foreigner, it must be approved by the relevant department in the State Council. When assigning the patent right, the client must conclude a written contract, which will take effect after being registered and announced by the Patent Office. Once the patent transfer right takes effect, the transferee obtains the status of patentee and the transferor loses the status of patentee. The patent transfer contract shall not affect the effectiveness of the transferor entering into a patent licensing contract with others before the establishment of the contract. Unless otherwise agreed in the contract, the rights and obligations stipulated in the original patent licensing contract shall be borne by the patent transferee. In addition, if the transferor has already exploited the patent before concluding the patent right transfer contract, unless otherwise agreed in the contract, the transferor shall stop the exploitation after the contract is established.