Optical scanning apparatus

Abstract

A scanning optical apparatus includes an optical box accommodating a deflection device for scanningly deflecting a laser beam emitted by a light source and an optical part for directing the laser beam toward a member-to-be-scanned; a cap mounted to the optical box; a sealing member extending from the cap, wherein the sealing member is made of a material exhibiting easier deformation than the cap, and is contacted to a wall of the optical box in a deformed state.

1 . A scanning optical apparatus comprising:
 an optical box accommodating a deflection device for scanningly deflecting a laser beam emitted by a light source and an optical part for directing the laser beam toward a member-to-be-scanned;   a cap mounted to said optical box;   a sealing member extending from said cap;   wherein said sealing member is made of a material exhibiting easier deformation than said cap, and is contacted to a wall of said optical box in a deformed state.   
   
   
       2 . A scanning optical apparatus according to  claim 1 , wherein said sealing member has an elastic coefficient which is larger than that of said cap. 
   
   
       3 . A scanning optical apparatus according to  claim 1 , wherein said sealing member is provided on said cap by insertion molding. 
   
   
       4 . A scanning optical apparatus according to  claim 1 , wherein the material of said sealing member is thermoplastic elastic material, and said cap has an inlet for permitting molten thermoplastic elastic material to enter at the time of the insertion molding, and a flow path for guiding the molten thermoplastic elastic material supplied through said inlet so that sealing member is molded so as to contact the wall of said optical box when said cap is mounted to said optical box. 
   
   
       5 . A scanning optical apparatus according to  claim 1 , wherein said sealing member forms an acute angle relative to the wall. 
   
   
       6 . A scanning optical apparatus according to  claim 5 , wherein said sealing member has a thickness which is smaller in a free end portion than in a base portion. 
   
   
       7 . A scanning optical apparatus according to  claim 5 , wherein a thickness of said sealing member in a range of ⅓ length from the free end is not more than ½ of the thickness in the base portion. 
   
   
       8 . A scanning optical apparatus according to  claim 5 , wherein said sealing member presses against the wall is not more than 100 gf per 1 cm of a circumferential length of sealing member. 
   
   
       9 . A scanning optical apparatus according to  claim 5 , wherein said sealing member has a volume resistivity R which satisfies,
   1×10 6  Ωcm≦ R ≦1×10 10  Ωcm.   
   
   
       10 . A scanning optical apparatus according to  claim 1 , wherein said sealing member includes a base portion extending from said cap and a contact portion contacting to the wall, and the contact portion is bent toward the wall from the wall. 
   
   
       11 . A scanning optical apparatus according to  claim 10 , wherein said contact portion has a thickness which is larger than that of said base portion. 
   
   
       12 . A scanning optical apparatus according to  claim 11 , wherein said sealing member has a volume resistivity R which satisfies,
   1×10 6  Ωcm≦ R ≦1×10 10  Ωcm.