Fixing device and image forming apparatus including the same
AssigneeRicoh Company, Ltd.
InventorsAkira Shinshi, Naoki Iwaya
Life of this patent
Estimating the term…
Abstract
A fixing device for an image forming apparatus of the present invention includes fixing roller and a pressing belt forming a nip therebetween. The fixing belt is passed over a drive roller and a driven roller and formed of a nonconductive material. A charge roller applies a charge opposite in polarity to a toner image carried on a sheet to the pressing belt from the outside surface of the belt. On contacting the pressing belt, the sheet is polarized with the result that a force attracting it toward the pressing belt increases. The sheet is therefore conveyed via the nip while being attracted by the belt 19 and does not or substantially does not wrap around the fixing roller.
Claims101
A fixing device for fixing a toner image carried on a sheet-like recording medium, said fixing device comprising:
- rotatable means facing each other for fixing the toner image on the recording medium by nipping and conveying said recording medium via a nip of said rotatable means, said rotatable means comprising a rotatable member positioned at a non-fixing side and contacting a non-image surface of said recording medium and a rotatable member positioned at a fixing side and facing said rotatable member positioned at said non-fixing side;
- and
- charging means for applying a charge to said rotatable member positioned at the non-fixing side to thereby cause the recording medium to be attracted toward said rotatable member positioned at said non-fixing side by an electrostatic force.
A fixing device for fixing a toner image carried on a sheet-like recording medium, said fixing device comprising:
- a pair of rotatable members facing each other for fixing the toner image on the recording medium by pressing and conveying said recording medium via a nip of said pair of rotatable members;
- and
- electrostatic attraction applying means for applying an electrostatic attracting force to either one of one of said pair of rotatable members and the recording medium;
- wherein part of a surface of said one rotatable member at least downstream of the nip attracts the recording medium while part of said surface upstream of said nip is substantially flat.
A fixing device for fixing a toner image carried on a sheet-like recording medium, said fixing device comprising:
- a pair of rotatable members facing each other for fixing the toner image on the recording medium by pressing and conveying said recording medium via a nip of said pair of rotatable members;
- and
- electrostatic attraction applying means for applying an electrostatic attracting force to either one of one of said pair of rotatable members and the recording medium;
- wherein part of a surface of said one rotatable member extending from a side upstream of the nip to a side downstream of said nip attracts the recording medium and is substantially flat.
A fixing device for fixing a toner image carried on a sheet-like recording medium, said fixing device comprising:
- a pair of rotatable members facing each other for fixing the toner image on the recording medium by pressing and conveying said recording medium via a nip of said pair of rotatable members, one of said pair of rotatable members comprising a conductive portion and a nonconductive portion closer to the other rotatable member than said conductive portion;
- and
- electrostatic attraction applying means for applying an electrostatic attracting force to said nonconductive portion of said one rotatable member.
A fixing device for fixing a toner image carried on a sheet-like recording medium, said fixing device comprising:
- a pair of rotatable members facing each other for fixing the toner image on the recording medium by pressing and conveying said recording medium via a nip of said pair of rotatable members, one of said pair of rotatable members comprising an outside surface facing the other rotatable member and an inside surface facing a center of rotation of said one rotatable member;
- and
- electrostatic attraction applying means for applying an electrostatic attracting force to the inside surface of said one rotatable member.
A fixing device for fixing a toner image carried on a sheet-like recording medium, said fixing device comprising:
- a pair of rotatable members facing each other for fixing the toner image on the recording medium by pressing and conveying said recording medium via a nip of said pair of rotatable members;
- electrostatic attraction applying means for applying an electrostatic attracting force to one of said pair of rotatable members;
- and
- charge applying means for applying a charge to the recording medium.
A fixing device for fixing a toner image carried on a sheet-like recording medium, said fixing device comprising:
- a pair of rotatable members facing each other for fixing the toner image on the recording medium by pressing and conveying said recording medium via a nip of said pair of rotatable members;
- and
- charge applying means for applying a charge to a non-image surface of the recording medium not carrying the toner image.
A fixing device for fixing a toner image carried on a sheet-like recording medium, said fixing device comprising:
- a pair of rotatable members facing each other for fixing the toner image on the recording medium by pressing and conveying said recording medium via a nip of said pair of rotatable members;
- electrostatic attraction applying means for applying an electrostatic attracting force to either one of one of said pair of rotatable members and the recording medium;
- and
- varying means for varying intensity of the electrostatic attracting force.
A fixing device for fixing a toner image carried on a sheet-like recording medium, said fixing device comprising:
- a pair of rotatable members facing each other for fixing the toner image on the recording medium by pressing and conveying said recording medium via a nip of said pair of rotatable members;
- and
- electrostatic attraction applying means for applying an electrostatic attracting force to at least part of a surface of one of said pair of rotatable members downstream of the nip;
- wherein the recording medium is electrostatically attracted toward the part of the surface of said one rotatable member downstream of the nip, but not electrostatically attracted toward part of said surface upstream of said nip.
In a fixing method for fixing a toner image carried on a sheet-like recording medium by conveying said recording medium via a nip between a pair of rotatable members facing each other, a charge is applied to one of said pair of rotatable members positioned at a non-fixing side, whereby said toner image is fixed on said sheet being attracted toward said one rotatable member by an electrostatic force.
In a fixing method for fixing a toner image carried on a sheet-like recording medium by conveying said recording medium via a nip between a pair of rotatable members facing each other, an electrostatic attracting force is applied to either one of one of said pair of rotatable members positioned at a non-fixing side and said recording medium, whereby said toner image is fixed on said sheet being electrostatically attracted toward said one rotatable member by an electrostatic force.
In an image forming apparatus for fixing a toner image carded on a sheet-like recording medium by conveying said recording medium via a fixing device, said fixing device comprising:
- rotatable means facing each other for fixing the toner image on the recording medium by nipping and conveying said recording medium via a nip of said rotatable means, said rotatable means comprising a rotatable member positioned at a non-fixing side and contacting a non-image surface of said recording medium and a rotatable member positioned at a fixing side and facing said rotatable member positioned at said non-fixing side;
- and
- charging means for applying a charge to said rotatable member positioned at the non-fixing side to thereby cause the recording medium to be attracted toward said rotatable member positioned at said non-fixing side by an electrostatic force.
In an image forming apparatus for fixing a toner image carried on a sheet-like recording medium by conveying said recording medium via a fixing device, said fixing device comprising:
- a pair of rotatable members facing each other for fixing the toner image on the recording medium by pressing and conveying said recording medium via a nip of said pair of rotatable members;
- and
- electrostatic attraction applying means for applying an electrostatic attracting force to either one of one of said pair of rotatable members and the recording medium;
- wherein part of a surface of said one rotatable member at least downstream of the nip attracts the recording medium while part of said surface upstream of said nip is substantially flat.
In an image forming apparatus for fixing a toner image carried on a sheet-like recording medium by conveying said recording medium via a fixing device, said fixing device comprising:
- a pair of rotatable members facing each other for fixing the toner image on the recording medium by pressing and conveying said recording medium via a nip of said pair of rotatable members;
- and
- electrostatic attraction applying means for applying an electrostatic attracting force to either one of one of said pair of rotatable members and the recording medium;
- wherein part of a surface of said one rotatable member extending from a side upstream of the nip to a side downstream of said nip attracts the recording medium and is substantially flat.
In an image forming apparatus for fixing a toner image carried on a sheet-like recording medium by conveying said recording medium via a fixing device, said fixing device comprising:
- a pair of rotatable members facing each other for fixing the toner image on the recording medium by pressing and conveying said recording medium via a nip of said pair of rotatable members, one of said pair of rotatable members comprising a conductive portion and a nonconductive portion closer to the other rotatable member than said conductive portion;
- and
- electrostatic attraction applying means for applying an electrostatic attracting force to said nonconductive portion of said one rotatable member.
In an image forming apparatus for fixing a toner image carried on a sheet-like recording medium by conveying said recording medium via a fixing device, said fixing device comprising:
- a pair of rotatable members facing each other for fixing the toner image on the recording medium by pressing and conveying said recording medium via a nip of said pair of rotatable members, one of said pair of rotatable members comprising an outside surface facing the other rotatable member and an inside surface facing a center of rotation of said one rotatable member;
- and
- electrostatic attraction applying means for applying an electrostatic attracting force to the inside surface of said one rotatable member.
In an image forming apparatus for fixing a toner image carried on a sheet-like recording medium by conveying said recording medium via a fixing device, said fixing device comprising:
- a pair of rotatable members facing each other for fixing the toner image on the recording medium by pressing and conveying said recording medium via a nip of said pair of rotatable members;
- electrostatic attraction applying means for applying an electrostatic attracting force to one of said pair of rotatable members;
- and
- charge applying means for applying a charge to the recording medium.
In an image forming apparatus for fixing a toner image carried on a sheet-like recording medium by conveying said recording medium via a fixing device, said fixing device comprising:
- a pair of rotatable members facing each other for fixing the toner image on the recording medium by pressing and conveying said recording medium via a nip of said pair of rotatable members;
- and
- charge applying means for applying a charge to a non-image surface of the recording medium not carrying the toner image.
In an image forming apparatus for fixing a toner image carried on a sheet-like recording medium by conveying said recording medium via a fixing device, said fixing device comprising:
- a pair of rotatable members facing each other for fixing the toner image on the recording medium by pressing and conveying said recording medium via a nip of said pair of rotatable members;
- electrostatic attraction applying means for applying an electrostatic attracting force to either one of one of said pair of rotatable members and the recording medium;
- and
- varying means for varying intensity of the electrostatic attracting force.
In an image forming apparatus for fixing a toner image carried on a sheet-like recording medium by conveying said recording medium via a fixing device, said fixing device comprising:
- a pair of rotatable members facing each other for fixing the toner image on the recording medium by pressing and conveying said recording medium via a nip of said pair of rotatable members;
- and
- electrostatic attraction applying means for applying an electrostatic attracting force to at least part of a surface of one of said pair of rotatable members downstream of the nip;
- wherein the recording medium is electrostatically attracted toward the part of the surface of said one rotatable member downstream of the nip, but not electrostatically attracted toward part of said surface upstream of said nip.
An image forming apparatus comprising:
- an image carrier configured to transfer a toner image to a recording medium;
- and
- a fixing device configured to receive the recording medium from the image carrier and including,
- a conveying member a charger configured to apply an electrostatic attracting force to the conveying member, and
- a processing unit configured to vary an intensity of the electrostatic attracting force.
A method for fixing a toner image on a recording medium, comprising:
- forming a nip between a first rotatable member and a second rotatable member, the second rotatable member being positioned at a non-fixing side;
- conveying the recording medium via the nip;
- applying a charge to the second rotatable member such that the recording medium is attracted to the second rotatable member by an electrostatic force;
- and
- fixing the toner image on the recording medium while the recording medium is attracted to the second rotatable member.
Dependencies are inferred from the claim text.