JPS60232574A - Image forming apparatus - Google Patents

Abstract

PURPOSE:To enable dew condensation of an optical system to be prevented by simple rearrangement without any cost by arranging a fixing device and an exhausting fan across the image forming optical system. CONSTITUTION:A transfer material 7 having a toner image transferred is separated from a photosensitive drum 2 with a separating means, conveyed in the arrow direction along a conveying route 10, the toner is fixed to the material 7 with a fixing roller 11 provided with a fixing heater 12 in the inside and a pressing roller 13 an then, the material 7 is ejected out of an ejection outlet 14 of the main body 1 of an electrophotographic copying machine. The fixing roller 11 is arranged on the left lower end of a diagonal drawn from the left lower part of the main body 1 to its right upper part, and the exhausting fan 15 is arranged on its right upper end, and the conveying route 10 of the material 7 is arranged in contact with the lower part of the photosensitive drum 2. Air flow 18 is allowed to enter through the outlet 14 below the left side of the fixing roller 11, cools the roller 11, advances toward the right upward direction and through a filter 17, passes along the outer circumference of the optical system 4 and through the fan 15, and is ejected out of an exhausting outlet 19.

Description

[Detailed description of the invention] The present invention relates to a dew condensation prevention device for an image forming apparatus.

Conventional image forming devices, such as electronic copying machines, suffer from condensation on the optical system when the room is rapidly heated during cold seasons such as winter or in cold locations, or when the electronic copying machine is moved from a cold location to a warm location. To prevent this, a planar heater, segment resistor, etc. were used to directly heat the optical system. These heaters are installed only to prevent condensation, which is one of the causes of high costs.

SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus in which dew condensation can be prevented simply by arranging an exhaust fan without providing any special dew condensation prevention means.

The present invention will be explained in more detail below with reference to the drawings.

FIG. 1 is a cross-sectional side view showing an embodiment of the present invention. A photosensitive drum is provided approximately in the center of an image forming apparatus, for example, an electronic copying machine main body l, and a charger 3 for activating the surface of the photosensitive drum is placed around the photosensitive drum a from upstream in the rotational direction of the arrow.
An optical system that exposes the photosensitive drum lζ by irradiating the original image; a developing device S1 that develops a latent image formed on the surface of the photosensitive drum due to the exposure; A transfer charger g for transferring, a cleaner for cleaning part of the developer remaining on the photosensitive drum a without being transferred to the transfer material? is the provision.

On the other hand, the transferred transfer material is separated from the photosensitive drum by a separating means (not shown), and is transported along the transport path 10 in the direction of the arrow.
The transfer material to which the developer has been fixed by the fixing roller with a built-in fixing heater saw and the pressure roller/3 is discharged from the outlet/4I.
is ejected from the electronic copying machine.

A fixing roller // is arranged at the lower left end of a diagonal line drawn from the lower left to the upper right of the electronic copying machine main body l, an exhaust fan 13 is arranged at the upper right end, and the transfer roller touches the lower part of the photosensitive drum. A conveyance path IO for the material 7 is arranged, a partition wall 16 partitions the fixing roller // and the photosensitive drum, and also the optical system and the developing device! , the paper feed cassette 6, etc., and the partition wall between the fixing roller and the optical system are equipped with a filter, and the air flow is located at the lower left outlet of the fixing roller. to cool the fixing roller l/,
The air flows toward the upper right, passes through the filter, passes around the optical system, passes through the exhaust fan 15, and is discharged from the exhaust port 19.

When the main switch is turned on, warm-up starts, the fixing heater is turned on, and the fixing roller l/ is warmed.

The air heated by the fixing roller l in the electronic copying machine main body l by the operation of the exhaust fan 15 causes air (1) flow i g to pass around the optical system, and this air flow tz
The optical system is warmed up during warm-up.

Therefore, dew condensation on the optical system is prevented, making it possible to always obtain clear images.

As explained above, the present invention provides an image forming apparatus that includes:
Because the fuser and exhaust fan are placed between the image optical system,
During warm-up, air heated by the fuser passes around the optical system and removes condensation from the optical system at that time, so it is possible to prevent condensation from the optical system at no cost by simply changing the arrangement. It became.

[Brief explanation of the drawing]

FIG. 7 is a sectional view of the main body of the electronic copying machine. l...Electronic copying machine main body K...Photosensitive drum...Optical system 10...Transport path l/...Fixing roller /2 Constant fixing heater 15--Exhaust fan /l...Air flow 19
··exhaust port. Patent Applicant Canon Co., Ltd. Agent Parti Arai

Claims (1)

[Claims] (l) An image forming apparatus characterized in that an exhaust fan is disposed diagonally above the fixing device, sandwiching the image optical system.