Legal analysis
Formal documents are usually signed with a water-based pen. Black ink pen or signature pen will be used to sign contract documents on formal occasions, because black ink pen or signature pen mainly contains carbon, which is known to those who have studied chemistry and is not easy to be oxidized. The main component is carbon black, that is, elemental carbon, which has stable chemical properties and black luster and is suitable for long-term preservation of writing materials. Ink pens are used less now. The widely used signature pens are divided into oil pens, gel pens and water pens. Although the matrix is different, for example, exams also use black pens. This is because when scanning the test paper, there will be light hitting the paper. If other colors are used, the handwriting will become unclear or even intermittent for some optical reasons, and it is difficult to explain it clearly in one or two sentences. So it's not that the blue one will be invisible, but the words written by the blue pen will be illegible. Most importantly, some colors will be ignored by the machine. It is recommended to use a black pen according to the regulations.
legal ground
People's Republic of China (PRC) Civil Code
Article 469 The parties may conclude a contract in writing, orally or in other forms. Written form refers to contracts, letters, telegrams, telexes, faxes and other forms that can tangibly express the contents contained. A data message that can tangibly express its content through electronic data interchange, e-mail, etc. , and can be retrieved at any time, are considered in writing.
Article 493 Where a contract is concluded by the parties in the form of a contract, the place where the contract is finally signed, sealed or fingerprinted is the place where the contract is established, unless otherwise agreed by the parties.
Article 502 A lawfully formed contract shall become effective upon its formation, unless otherwise provided by law or agreed by the parties. In accordance with the provisions of laws and administrative regulations, if the contract should go through the approval procedures, such provisions shall prevail. If the failure to go through the formalities such as approval affects the effectiveness of the contract, it will not affect the performance of the obligation clauses such as approval and the effectiveness of relevant clauses in the contract. If the party that should go through the formalities for approval fails to perform its obligations, the other party may require it to bear the responsibility for violating its obligations. The modification, assignment and dissolution of a contract shall be subject to the provisions of laws and administrative regulations, and the provisions of the preceding paragraph shall apply and shall be subject to approval.