Method and apparatus for image forming capable of effectively cleaning a transfer mechanism

An image forming apparatus, comprising:

• photoconductive member means;
• charging means for charging a surface of said photoconductive member means;
• developing means, configured to contact said photoconductive member means to transfer toner thereto, for developing an image on said surface of said photoconductive member means, said toner in a normal charged condition having a same polarity as a polarity of a charge of said photoconductive member means;
• transferring means for transferring said image developed by said developing means from said photoconductive member means onto a recording sheet;
• and
• power supply means for supplying a first voltage to said transferring means when a region of said surface of said photoconductive member means charged by said charging means passes through a development region at which said photoconductive member means and said developing means contact each other without having a development operation performed by said developing means, and reaches a transfer region at which said photoconductive member means and said transferring means contact each other under a condition in which no recording sheet exists therebetween, said first voltage having a same polarity as a polarity of a second voltage applied to said transferring means during a normal transfer operation,
• wherein said photoconductive member means is exposed to light for a time period in which said photoconductive member means moves one rotation or more to reduce a voltage of an entire surface thereof after said photoconductive member means is charged by said charging means but before an image is output and an image forming operation is ended,
• wherein said developing means is applied with a voltage having a reverse-polarity relative to a voltage applied to said developing means during a normal development operation when a region of said surface of said photoconductive member means having said reduced voltage reaches said development region,
• wherein said power supply means is caused to apply to said transfer roller means for a predetermined time period a voltage having a same polarity relative to a voltage applied to said toner during said normal development operation when said region of said surface of said photoconductive member means having said reduced voltage reaches said transfer region, and
• wherein said transferring means is grounded for a predetermined time period.

A method of image forming, comprising the steps of:

• charging a surface of a photoconductive member;
• exposing said surface of said photoconductive member in accordance with image information;
• first causing a development roller to develop an image on said surface of said photoconductive member using toner which is in a normal charged condition having a same polarity as a polarity of a charge applied to said photoconductive member;
• second causing a transfer roller to transfer said image developed by said developing step from said photoconductive member onto a recording sheet with an application of a first voltage from a power supply source;
• third causing said power supply source to supply a second voltage to said transfer roller when a region of said surface of said photoconductive member charged by said charging step passes through a development region without having a development operation performed by said developing step, and reaches a transfer region under a condition in which no recording sheet exists in said transfer region, said second voltage having a same polarity as a polarity of said first voltage,
• wherein said exposing step exposes said surface of said photoconductive member to light for a time period in which said photoconductive member moves one rotation or more to reduce a voltage of an entire surface thereof after said photoconductive member is charged by said charging step but before an image is output and an image forming operation is ended,
• wherein said developing step includes the step of applying to said development roller a voltage having a reverse-polarity relative to a voltage applied to said development roller during a normal development operation when a region of said surface of said photoconductive member having said reduced voltage reaches said development region,
• wherein said third causing step applies to said transfer roller for a predetermined time period a voltage having a same-polarity relative to a voltage applied to said toner during said normal development operation when said region of said surface of said photoconductive member having said reduced voltage reaches said transfer region, and
• wherein said transfer roller is grounded for a predetermined time period.