LIQUID INJECTION DEVICE AND PRODUCTION LINE

A liquid injection device comprises a vacuumizing air path, first-level and second-level cups, injection paths, and liquid flowing assemblies. The first-level cup is formed with a plurality of buffer cavities that are isolated from each other; the second-level cup is formed with a plurality of liquid injection cavities that are isolated from each other; the liquid injection cavities are all communicated with the vacuumizing air path; each injection path is communicated with one buffer cavity; the liquid flowing assemblies, the buffer cavities, and the liquid injection cavities are arranged in a one-to-one correspondence manner; each liquid flowing assembly comprises a liquid flowing channel and a first switch element; the liquid flowing channel is communicated with one buffer cavity and one liquid injection cavity; and the first switch element is arranged in the liquid flowing channel to selectively open or close the liquid flowing channel.