Image forming apparatus with first and second transfer sections

• US 7,689,152 B2
• Filed: 12/27/2006
• Issued: 03/30/2010
• Est. Priority Date: 01/23/2006
• Status: Active Grant

• Current Assignee: Konica Minolta Business Technologies Incorporated (Konica Minolta Inc.)
• Original Assignee: Konica Minolta Business Technologies Incorporated (Konica Minolta Inc.)
• Inventors: Ishizuka, Kazuteru, Kurosu, Shigetaka, Nishida, Satoshi, Sako, Mineyuki
• Primary Examiner(s): Gray; David M
• Assistant Examiner(s): Do; Andrew V
• Application Number:
  US11/646,145
• Publication Number:
  US 20070172267A1
• Time in Patent Office: 1,189 Days
• Field of Search: 399/302, 399/310, 399/314
• US Class Current: 399/302
• CPC Class Codes: G03G 15/1605 using at least one intermediate support G03G15/1625 takes precedence
• CPC Class Codes: G03G 15/161 with means for handling the intermediate support, e.g. heating, cleaning, coating with a transfer agent
• CPC Class Codes: G03G 2215/1614 Transfer roll
• CPC Class Codes: G03G 2215/1652 of transfer roll

Abstract

An image forming apparatus may include a first transfer section for transferring a toner image, formed on an image carrier by utilizing a charging section, an exposing section and a developing section, onto a belt shaped intermediate transfer member; and a second transfer section for transferring the toner image on the intermediate transfer member onto a recording material by applying an electric field between a second transfer roller being provided outside the intermediate transfer member and a backup roller being provided inside the intermediate transfer member, the second transfer roller and the backup roller sandwiching the intermediate recording member and the recording material. The second transfer roller may be grounded and a bias voltage may be applied to the backup roller, and a second charging section for charging a surface of the second transfer roller with a predetermined polarity may be included.

Claims

1. An image forming apparatus comprising:

a first transfer section for transferring a toner image, which is formed on an image carrier by utilizing a charging section, an exposing section and a developing section, onto an intermediate transfer member having a belt shape; and

a second transfer section for transferring the toner image transferred on the intermediate transfer member onto a recording material by applying an electric field between a second transfer roller being provided outside the intermediate transfer member and a backup roller being provided inside the intermediate transfer member, the second transfer roller and the backup roller sandwiching an intermediate recording member and the recording material;

wherein a bias voltage having a same polarity as a polarity of toner forming the toner image to be transferred is applied to the backup roller through a metal shaft of the backup roller when transfer operation is conducted by the second transfer section, and bias voltage having an opposite polarity to the polarity of toner is applied to the backup roller through the metal shaft of the backup roller when transfer operation is not conducted by the second transfer section;

wherein a metal shaft of the second transfer roller is constantly grounded and further provided is a second charging section for charging a surface of the second transfer roller;

wherein the second charging section charges the surface of the second transfer roller with a same polarity as a polarity of toner forming the toner image to be transferred when a transfer operation by the second transfer section is not conducted;

wherein the second charging section comprises s corona discharging electrode.

2. The image forming apparatus of claim 1, wherein the second charging section is enable to apply a bias voltage, on which AC voltage is superimposed, to the surface of the second transfer roller.

3. The image forming apparatus of claim 1, wherein the second transfer roller presses the backup roller.