| 摘要 |
PROBLEM TO BE SOLVED: To realize control in accordance with the state of a machine and to prevent an optical system from being soiled by varying the cooling ratio of the inside of an optical system unit to the inside of an image forming unit. SOLUTION: As for a cooling means 30 for cooling the inside of the optical system unit 10 and the inside of the image forming unit 20; air inside the unit 10 is exhausted by the rotation by itself. The machine is provided with a cooling fan 31 exhausting the air inside the unit 20. By the rotation of the fan 31, the air inside the unit 10 and the air inside the unit 20 are discharged to the outside of the machine. The machine is provided with a control means to very the cooling rate between the inside of the unit 10 and the inside of the unit 20. As the control means, it is provided with an opening/closing member 41 capable of varying the cross section communicating an optical system exhaust path 32 and set at the middle of the path 32 communicating the unit 10 and the fan 31. |
