ใจ is a particle that marks something as a quotation in the form of a single noun, and makes that noun function as a modifier to the primary verb in the clause.1
Example: As for Yui, she said "late! late!".
็ต่กฃใกใใใฏใใใใ๏ผใใใ๏ผใใจ่จใฃใ
Info
In this example, ็ต่กฃใกใใ/ใใใกใใ (Yui-chan) is marked by the ใฏ particle, making her the primary topic of the sentence.
ๆ่จ/ใจใใ (clock) is marked by ใ, so it the object of the sentence.
The primary verb ่จใ/ใใ (say) is in the ใ-form, placing the sentence into the past tense.
ใใใใ๏ผใใใ๏ผใ has quotation brackets to clarify the start and end points of the quotation. The ใจ particle marks it as a quotation in the form of a single noun, and makes it act as a modifier for the proceeding verb, telling us more about it.
The subject of the sentence is inferred from context to be ็ต่กฃใกใใ (Yui-chan), as the ใ particle is omitted.