Image forming apparatus

Patent metadata

Field	Value
Publication number	US-9229350-B2
Application number	US-76819310-A
Country	US
Kind code	B2
Filing date	Apr 27, 2010
Priority date	Aug 19, 2009
Publication date	Jan 5, 2016
Grant date	Jan 5, 2016

Abstract

An image forming apparatus includes an image carrier; a transferring unit; a fixing unit; a conveying unit; and a sheet shape detecting unit as defined herein, and a discharge position where the sheet is discharged from the conveying path, a feed position where the sheet is fed to the sheet conveying path and a detection position where the shape of the sheet is detected by the sheet shape detecting unit are arranged in this sequence along a sheet conveying direction to be close to one another, immediately downstream in the sheet conveying direction from a fixing position where the toner image is fixed to the sheet.

First claim

What is claimed is:

1. An image forming apparatus comprising:
an image carrier on which a plurality of toner images is formed, each of the toner images corresponding to a different color;
a developing unit that develops an electrostatic latent image formed on the image carrier to sequentially form the toner images on the image carrier;
a transferring unit that transfers the toner image formed on the image carrier to a sheet at a transfer position;
a fixing unit that fixes the toner image transferred to the sheet at a fixing position;
a conveying unit that conveys the sheet along a conveying path that circulates around the image carrier, to repeatedly transfer and fix the plurality of toner images to the sheet, each of the toner images being sequentially transferred and fixed to the sheet one at a time;
a sheet shape detecting unit that detects information indicative of a shape of the sheet that is conveyed through the conveying path;
a discharge position where the sheet is discharged from the conveying path, a feed position where the sheet is fed to the conveying path and a detection position where the information indicative of the shape of the sheet is detected by the sheet shape detecting unit are arranged in this sequence along a sheet conveying direction to be close to one another, immediately downstream in the sheet conveying direction from the fixing position where the toner image is fixed to the sheet,
a distance from the feed position along the conveying path in the sheet conveying direction to the discharge position is greater than a distance from the discharge position along the conveying path in the sheet conveying direction to the feed position, and a distance from the feed position along the conveying path in the sheet conveying direction to the transfer position, where each of the toner images is sequentially transferred to the sheet one at a time, is greater than a distance from the transfer position along the conveying path in the sheet conveying direction to the feed position,
wherein the discharge position, the feed position and the detection position are on a same side with respect to a first plane which is perpendicular to a second plane connecting the transfer position of the transferring unit to the fixing position of the fixing unit and which passes through the transfer position, the second plane connecting the transfer position of the transferring unit to the fixing position of the fixing unit being substantially vertical, and
wherein a length of a conveying path extending from the detection position to the transfer position in the conveying direction is equal to or greater than the maximum sheet length for the image forming apparatus.

2. The image forming apparatus according to claim 1 , further comprising:
a feed sheet housing portion for housing the sheet prior to conveyance along the conveying path; and
a discharge sheet housing portion for housing the sheet after discharge from the conveying path,
wherein the feed sheet housing portion and the discharge sheet housing portion are placed so that a first path portion of the conveying path, the first path portion extending from the transfer position to the fixing position, a sheet which is housed in the feed sheet housing portion, and a sheet which is housed in the discharge sheet housing portion are opposed to one another.

3. The image forming apparatus according to claim 2 , wherein
the feed sheet housing portion is placed to be opposed to the first path portion across a second path portion of the conveying path, the second path portion extending from the fixing position to the transfer position, and
the discharge sheet housing portion is placed to be opposed to the first path portion across the second path portion and the feed sheet housing portion.

4. An image forming apparatus comprising:
an image carrier on which a plurality of toner images is formed, each of the toner images corresponding to a different color;
a developing unit that develops an electrostatic latent image formed on the image carrier to sequentially form the toner images on the image carrier;
a transferring unit that transfers the toner image formed on the image carrier to a sheet at a transfer position;
a fixing unit that fixes the toner image transferred to the sheet at a fixing position;
a conveying unit that conveys the sheet along a conveying path that circulates around the image carrier, to repeatedly transfer and fix the plurality of toner images to the sheet, each of the toner images being sequentially transferred and fixed to the sheet one at a time;
a sheet shape detecting unit that detects information indicative of a shape of the sheet that is conveyed through the conveying path;
a discharge position where the sheet is discharged from the conveying path, a feed position where the sheet is fed to the conveying path and a detection position where the information indicative of the shape of the sheet is detected by the sheet shape detecting unit are arranged in this sequence along a sheet conveying direction to be close to one another, immediately downstream in the sheet conveying direction from the fixing position where the toner image is fixed to the sheet,
wherein the discharge position, the feed position and the detection position are on a same side with respect to a first plane which is perpendicular to a second plane connecting the transfer position of the transferring unit to the fixing position of the fixing unit and which passes through the transfer position, the second plane connecting the transfer position of the transferring unit to the fixing position of the fixing unit being substantially vertical, and
wherein a length of a conveying path extending from the detection position to the transfer position in the conveying direction is equal to or greater than the maximum sheet length for the image forming apparatus.

Assignees

• Okamoto Tetsuji
• Kitamura Atsuyuki
• Sato Masahiro
• Ogihara Atsushi
• Murakami Junichi
• Nishide Shuichi
• Fuji Xerox Co Ltd

Inventors

• Okamoto Tetsuji
• Kitamura Atsuyuki
• Sato Masahiro
• Ogihara Atsushi
• Murakami Junichi
• Nishide Shuichi

Classifications

• G03G15/0173

  plural rotations of recording member to produce multicoloured copy, e.g. rotating set of developing units (G03G15/0163 takes precedence) · CPC title

• G03G2215/0177

  Rotating set of developing units · CPC title

• G03G15/0163 Primary

  primary transfer to the final recording medium · CPC title

• B65H2405/3321

  Feed tray superposed to discharge tray · CPC title

• B65H2405/3322

  discharge tray superposed to feed tray · CPC title