Browse Prior Art Database

Ring Gate Mold Design

IP.com Disclosure Number: IPCOM000100664D
Original Publication Date: 1990-May-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 69K

Publishing Venue

IBM

Related People

Cochran, DE: AUTHOR [+2]

Abstract

This article describes a mold design that allows for the molding of defect-free rolls.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 53% of the total text.

Ring Gate Mold Design

       This article describes a mold design that allows for the
molding of defect-free rolls.

      Monocomponent nonmagnetic developers commonly employ a
developer roll that transfers toner from the sump to the
photoconductor.  The developer roll is generally made from an
elastomer in order to provide a compliant surface.  The developer
roll can also be coated to provide the desired surface properties for
the application.  The method in which the roll is molded from the
elastomer is critical for its final surface characteristics.  A
common method to mold such a roller is to transfer mold the elastomer
through a series of sprues, runners, and gates such that the material
enters the mold cavity along the parting line between the mold halves
in a symmetric fashion.  This allows for rapid filling of the mold
but can leave defects along the finished roll surface. Compression
molding could also be employed (where each roll has the uncured
elastomer wrapped around the shaft prior to placing the shaft in the
mold), but this is not preferred due to increased labor costs.

      We have found a mold design which allows for the molding of
defect-free parts in an economical fashion.  The concept is a ring
gate design where the mold cavity is filled from the outside diameter
of one end of roll into the cavity.  This design allows for the
material to flow from one end of the cavity to the other without
leaving gate marks on the finished surface...