US 2013/0156454 A1 · DEVELOPING DEVICE, IMAGE FORMING APPARATUS AND METHOD OF CONTROLLING DEVELOPING DEVICE

Abstract

A developing device includes a development roller, a magnetic roller, a transformer, a switching portion, output control portion and a capacitor. The development roller is opposite a photoconductor drum. The magnetic roller performs, with a magnetic brush, the supply of a toner to the development roller and the removal of the toner. The transformer generates an alternating-current voltage applied to the development roller. The switching portion passes and interrupts a current to the transformer. The output control portion stepwise changes, when a duty ratio in switching is changed, the duty ratio a plurality of times from a first duty ratio to a second duty ratio. The capacitor has one end connected to the transformer and the other end connected to the switching portion.

Claims15

Dependent claims

A developing device comprising:

a development roller which bears a toner and which is opposite a photoconductor drum;
a magnetic roller which is arranged opposite the development roller and which performs, with a magnetic brush, supply of the toner to the development roller and removal of the toner from the development roller;
a transformer which generates an alternating-current voltage applied to the development roller;
a switching portion which passes and interrupts a current to the transformer;
a output control portion stepwise changes the duty ratio a plurality of times from the first duty ratio to the second duty ratio, when a duty ratio in switching performed by the switching portion is changed from a first duty ratio to a second duty ratio;
and
a capacitor in which one end is connected to the transformer and the other end is connected to the switching portion.

4 more elements

A method of controlling a developing device comprising:

generating, by a transformer, an alternating-current voltage applied to the development roller;
passing and interrupting, by switching of a switching portion, a current to the transformer;
and
stepwise changing, when a duty ratio in switching performed by the switching portion is changed from a first duty ratio to a second duty ratio, the duty ratio a plurality of times from the first duty ratio to the second duty ratio.

1 more element

Dependencies are inferred from the claim text.

Developing device, image forming apparatus and method of controlling developing device

Life of this patent

Developing device, image forming apparatus and method of controlling developing device

Life of this patent

Abstract

Claims15