METAL MOLD FOR MANUFACTURING ROTARY POLYGON MIRROR

• Main Authors: SAGAWA TAKESHI, TANI MASATO
• Format: Patent
• Language: English
• Published: 02.05.1997
• Edition: 6
• Subjects: AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING; INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULARARTICLES; OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICS; PERFORMING OPERATIONS; PHYSICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDEDFOR; SHAPING OR JOINING OF PLASTICS; TRANSPORTING; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL

PROBLEM TO BE SOLVED: To prevent trouble such as unevenness from being generated at the part where a motor shaft is fitted by shifting the center position of a gate at which the resin is injected from the inner peripheral surface side to the outer peripheral surface side of a rotary polygon mirror, by a specific quantity from the center position of a shaft holding part. SOLUTION: The metal mold 20A for rotary polygon mirror manufacture is formed so that the position of the gate 3 at which the resin 60 is injected from the inner peripheral surface (shaft fitting-in part 9 side) to the outer peripheral surface (mirror surface 7 side) of the rotary polygon mirror 10A is shifted by the specific shift quantity Δ from the position H0 facing the holding part 50b for the motor shaft 50 driving the rotary polygon mirror 10A and moved to a position H1 . When the position of the gate 3 is shifted from H0 to H1 , a means for guiding the resin 60 injected from the gate 3 toward the reference point K of the mirror surface 7 needs to be taken. In this case, a dummy space 40 of a dummy quantity Δ1 corresponding to the shift quantity Δ of the gate 3 is formed nearby the gate 3 to guide the resin toward the reference point K.