1. Field of the Invention
The present invention relates to a processing head incorporated in an electrophotographic apparatus for executing various kinds of processing of electrophotographic films.
2. Description of the Prior Art
One type of photographic apparatus has heretofore been known which is capable of recording an image on a predetermined frame of a photographic film and of projecting or copying the recorded image.
A processing head is disposed in such photographic apparatus to subject an electrophotographic film to various kinds of processing such as charging/exposure and development, and such a processing head is known from the specifications of U.S. Pat. Nos. 4,591,543, 4,600,291, 4,613,226 4,623,240, 4,671,648 and so forth.
The processing head disclosed in the above-mentioned specifications has a charging exposure section, a developing section, a drying section, and a fixing section. These sections are disposed side by side in the mentioned order in the direction in which an electrophotographic film is fed at a constant pitch which corresponds to the pitch of frames of the electrophotographic film.
In the charging exposure section, a portion of the electrophotographic film (corresponding to one frame of the film) which is positioned at this section is charged and is then exposed to light reflected from a document carrying an image. By this operation, an electrostatic latent image which corresponds to the image pattern on the document is formed on the frame of the electrophotographic film. In the developing section, the frame of film which has been subjected to exposure in the charging exposure section is coated with a liquid developer so as to make the electrostatic latent image visible. In the image section, dry air is applied to the frame of film which is wet from the liquid developer so as to remove moisture therefrom. In the fixing section, the image is fixed on the frame of film by means of a fixing lamp or the like.
With this processing head, part of the liquid developer coated on the electrophotographic film after the film has been charged and exposed may remain in the developing section, particularly on a developing electrode thereof, and adhere thereto as surplus developer after the completion of the developing. In order to remove the surplus developer, the processing head is adapted to use air to swish off the surplus developer.
However, there is a fear that some of the surplus developer may not be removed and may, instead, dry and become solidified. The amount of surplus developer adhering to and being deposited on the developing electrode will increase as the number of times development is performed increases. When the amount of the surplus developer adhering to and deposited on the developing electrode in this way exceeds a certain level, some of the surplus developer may become partially exfoliated and turned away from the electrode, projecting toward the space between the electrophotographic film and the electrode, that is, into the developing chamber. The solidified developer which projects in this way may disturb the flow of developer which will flow in the developing chamber during the developing of subsequent frames, causing non-uniform flow of the developer. This may result in the formation of defective images.