Image forming apparatus

• US 20020001476A1
• Filed: 08/02/2001
• Published: 01/03/2002
• Est. Priority Date: 06/26/1998
• Status: Abandoned Application

• Current Assignee: Katsumi Takada, Susumu Imado, Tomoyuki Nagamine
• Original Assignee: Katsumi Takada, Susumu Imado, Tomoyuki Nagamine
• Inventors: Nagamine, Tomoyuki, Takada, Katsumi, Imado, Susumu
• Application Number:
  US09/919,851
• Publication Number:
  US 20020001476A1
• Time in Patent Office: Days
• US Class Current: 399/45
• CPC Class Codes: G03G 15/2035 for maintenance purposes, e.g. for removing a jammed sheet
• CPC Class Codes: G03G 2221/1639 for the fixing unit
• CPC Class Codes: G03G 2221/1687 using opening shell type machines, e.g. pivoting assemblies

Abstract

An image forming apparatus has a plurality of print assemblies for forming a color image, a fixing unit, and a paper conveyor belt for conveying a paper sheet through the print assemblies and the fixing unit. The fixing unit includes a pair of fixing rollers, a nip control mechanism for moving the pair of the fixing rollers between a nip position and a non-nip position, and a fixing unit securing means movable with the nip control mechanism. Thus, the fixing unit can be easily mounted and demounted.

Claims

1. An image forming apparatus comprising:

a frame;

at least one print assembly capable of forming an image;

a fixing unit including a pair of fixing rollers for holding and conveying a paper sheet, a nip control mechanism for moving-said pair of fixing rollers between a nip position and a non-nip position, and fixing unit securing means movable with said nip control mechanism for securing and releasing the fixing unit to and from the frame; and

a paper sheet conveyor means for conveying the paper sheet to said fixing unit through said print assembly.

2. An image forming apparatus according to claim 1, characterized in that said at least one print assembly includes a plurality of print assemblies, each of said print assemblies includes a photosensitive member, a charger for charging said photosensitive member, latent image forming means for forming an electrostatic latent image on said photosensitive member, a developing unit for developing said electrostatic latent image, and a transfer element for transferring a developed toner image to the paper sheet, said latent image forming means being mounted on a top cover which is movably mounted on the frame to cover said print assembly.

3. An image forming apparatus according to claim 1, characterized in that said nip control mechanism moves with said end cover when said end cover moves from an open position to a closed position.

4. An image forming apparatus according to claim 1, characterized in that said frame has a positioning pin inserted in a hole of said fixing unit for positioning said fixing unit, and said fixing unit securing means includes a lock member adapted to engage said positioning pin in cooperation with said nip control mechanism.

5. An image forming apparatus according to claim 4, characterized in that said nip control mechanism includes manually operable levers, said lock member includes a cam plate movable with said levers, and said positioning pin has a small-diameter portion adapted to engage said cam plate.

6. An image forming apparatus comprising:

a frame;

at least one print assembly capable of forming an image;

a pair of fixing rollers for holding and conveying a paper sheet, an inlet-side paper guide arranged to be movable in a vertical direction with respect to a paper passage in accordance with a thickness of the paper sheet and guiding the paper sheet between said fixing rollers; and

paper conveyor means for conveying the paper sheet to said fixing rollers through said print assembly and said inlet-side paper guide.

7. An image forming apparatus according to claim 6, characterized in that said inlet-side paper guide comprises an elastic material which is flexible in accordance with the thickness of the paper.

8. An image forming apparatus according to claim 6, further comprising means for moving said inlet-side paper guide in accordance with a kind of the paper sheet.

9. An image forming apparatus comprising:

a frame;

at least one print assembly capable of forming an image;

a fixing unit having a pair of fixing rollers for holding and conveying a paper sheet;

a paper sheet conveyor belt for conveying the paper sheet through said print assembly and said fixing unit; and

means capable of changing a speed of said fixing rollers relative to a speed of said paper sheet conveyor belt in accordance with a kind of the paper sheet.

10. An image forming apparatus comprising:

a frame;

at least one print assembly capable of forming an image;

a fixing unit including a pair of fixing rollers for holding and conveying a paper sheet, and a cleaning member having at least two strips of cleaning felt arranged so that contact pressures of said two strips of cleaning felt against said fixing roller are changed in the rotational direction of said fixing roller to clean the surface of said fixing roller; and

paper conveyor means for conveying the paper sheet through said print assembly and said fixing unit.