Centrifugal casting die, method for manufacturing thereof as well as casting material, blade obtained therefrom and method for manufacturing thereof

Abstract

A centrifugal casting die according to the present invention includes a cylindrical die body, a backup layer releasably bonded to the inner surface 12b of the die body, and a top layer bonded to be integral to the inner surface of the backup layer, for holding a centrifugally casting material supplied to the inner surface thereof, whereby the centrifugally casting material having a uniform thickness is easily releasable from the centrifugal casting die without using a die-lubricant.

Description

[0001]This application claims priority from Japanese Patent Application Nos. 2002-136191 filed May 10, 2002, 2002-136190 filed May 10, 2002 and 2003-117441 filed Apr. 22, 2003, which are incorporated hereinto by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to a centrifugal casting die for casting a thin-walled cylindrical resinous material and a method for manufacturing the casting die as well as the casting material by using the same, a blade used in an electrophotographic apparatus and a method for manufacturing the blade.[0004]2. Description of the Related Art[0005]A schematic structure of a conventional electrophotographic apparatus is shown in FIG. 7, which carries out a contact-charging process and a contact-transfer process without using a corona discharge. That is, an electro-photosensitive drum 101 on which an electrostatic latent image is formed is provided with an electroconductive basic layer made, for example, o...

AI Technical Summary

Benefits of technology

[0014]An object of the present invention is to provide a centrifugal casting die from which a centrifugally casting material is easily removable without using a die-lubricant, and which is capable of being repeatedly used and easily refreshed, as well as to provide a method for manufacturing such a casting die.

[0015]Another object of the present invention is to provide cylindrical centrifugally casting materials excellent in quality and having a uniform thickness manufactured by using such a centrifugal casting die, blades used in an electrophotographic apparatus and a method for manufacturing the blades.

Problems solved by technology

When a center axis of the rotary shaft 110b is eccentric from a center axis of the inner surface 110c of the conventional die body 110 shown in FIG. 8, or the deviation from circular form of the inner surface 110c of the die body 110 is low, vibration occurs in the inner surface 110c of the die body 110 during the rotation of the casting die, causing the uneven distribution of centrifugal force in the circumferential direction thereof and results in an inconvenience in that a wall thickness of the obtained thin-walled resinous cylindrical material 111 lacks the uniformity in the circumferential direction.

Particularly, when the silicone rubber having the deterioration in releasability is removed from the inner surface of the die body, the silicone rubber is liable to be torn and left on the inner surface.

The complete removal thereof from the inner surface of the die body necessitates an extremely large amount of man-hours.

As a result, when the obtained thin-walled centrifugally casting material is processed to a blade or others of the electrophotographic apparatus, it is liable to adhere to a casting jig or others and difficult to be handled to lower the workability.

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