US 5,799,229 A · Toner spreading device for a charging roller of an image forming apparatus

Abstract

An image forming apparatus including a photoconductive drum, a charging roller which is held in pressured contact with the photoconductive drum, and a holder which holds a spreading blade having a free or unsupported end which is held in contact with the charging roller to spread toner and other particles which adhere to the surface of the charging roller. Preferably, there is a thin flexible film between the holder and the spreading blade. The spreading blade is held by the holder such that when the charging roller rotates, a frictional force pulls the spreading blade relative to the holder. This frictional force imposes a rotational moment on the spreading blade which reduces the force of the spreading blade against the charging roller when the charging roller rotates. In order to extend the life of the spreading blade and to achieve a uniform distribution of the particles on the charge roller, the spreading blade may be moved in a reciprocating motion along a plane tangential to the surface of the roller and/or along the length of the roller. The spreading blade spreads the toner and other particles which adhere to the surface of the charging roller into a thin uniform layer so that the charging roller uniformly charges the photoconductive drum.

Claims48

Dependent claims

A charging device, comprising:

a charging roller which charges an image bearing member and rotates in a predetermined direction;
a holder, and
a spreading blade having a contact surface and a width which is parallel to the contact surface, the width having a first end and a second end opposite to the first end, the first end being a free end which is unsupported and the second end being supported by the holder, the contact surface being held in contact with said charging roller to spread toner adhered to a surface of the charging roller when the charging roller rotates in the predetermined direction,
wherein the holder supports said spreading blade at the second end so that a frictional force acting on the spreading blade, which results from contact between the charging roller and spreading blade when the charging roller rotates in the predetermined direction, urges the spreading blade away from the holder.

1 more element

An image forming device for forming a toner image on a sheet of paper, comprising:

a photoconductive member;
a charging roller which charges the photoconductive member and rotates in a predetermined direction;
a holder, and
a spreading blade having a contact surface and a width which is parallel to the contact surface, the width having a first end and a second end opposite to the first end, the first end being a free end which is unsupported and the second end being supported by the holder, the contact surface being held in contact with said charging roller to spread toner adhered to a surface of the charging roller when the charging roller rotates in the predetermined direction,
wherein the holder supports said spreading blade at the second end so that a frictional force acting on the spreading blade, which results from contact between the charging roller and spreading blade when the charging roller rotates in the predetermined direction, urges the spreading blade away from the holder.

2 more elements

Dependencies are inferred from the claim text.

Toner spreading device for a charging roller of an image forming apparatus

Life of this patent

Toner spreading device for a charging roller of an image forming apparatus

Life of this patent

Abstract

Claims48