Fixing device and image forming apparatus
A fixing device includes a fixing film, a heater for heating the fixing film, a heater holder including a heater holding portion holding the heater, and a pressing roller forming a nip between itself and the fixing film to be heated by the heater. In the nip, a toner image carried on a recording material is fixed. The heater holder includes an opposing surface which is provided on a side upstream of the heater holding portion with respect to a recording material feeding direction and which opposes the pressing roller, a lubricant holding portion provided on the opposing surface, for supplying a lubricant to between the fixing film and the heater, and a projected portion provided on the side upstream of the heater holding portion with respect to the recording material feeding direction and projecting toward the pressing roller from the opposing surface.
1. A fixing device comprising:
a fixing film;
a heater configured to heat said fixing film;
a heater holder including a heater holding portion holding said heater; and
a pressing roller forming a nip, between itself and said fixing film to be heated by said heater, in which a toner image carried on a recording material is fixed,
wherein said heater holder comprises:
an opposing surface which is provided on a side upstream of said heater holding portion with respect to a recording material feeding direction and which opposes said pressing roller;
a lubricant holding portion provided on said opposing surface and configured to supply a lubricant to between said fixing film and said heater; and
a projected portion provided on a side upstream of said heater holding portion with respect to the recording material feeding direction and projecting toward said pressing roller from said opposing surface,
wherein with respect to the recording material feeding direction, said opposing surface located upstream of said lubricant holding portion does not contact said fixing film, but said opposing surface located downstream of said lubricant holding portion contacts said fixing film.
2. A fixing device according to claim 1 , wherein said opposing surface is projected more toward said pressing roller than the nip is projected.
3. A fixing device according to claim 1 , wherein when said opposing surface is seen from said pressing roller side in a direction perpendicular to the feeding direction and perpendicular to a longitudinal direction of said heater holder perpendicular to the feeding direction, said lubricant holding portion has an elliptical shape, a rectangular shape or a diamond shape.
4. A fixing device according to claim 1 , wherein when said opposing surface is seen from said pressing roller side in a direction perpendicular to the feeding direction and perpendicular to a longitudinal direction of said heater holder perpendicular to the feeding direction, a length of said lubricant holding portion with respect to the longitudinal direction of said heater holder is longer at a portion far from the nip than at a portion near to the nip.
5. A fixing device according to claim 1 , wherein a longitudinal direction of said lubricant holding portion forms a predetermined angle with respect to the feeding direction.
6. A fixing device according to claim 1 , wherein said lubricant holding portion includes a plurality of lubricant holding parts with respect to a longitudinal direction of said heater holder.
7. A fixing device according to claim 6 , wherein said lubricant holding parts are provided at regular intervals.
8. A fixing device according to claim 6 , wherein when said opposing surface is seen from said pressing roller side in a direction perpendicular to the feeding direction and perpendicular to a direction of said heater holder perpendicular to the feeding direction, areas of said lubricant holding parts change depending on positions thereof with respect to the longitudinal direction and/or intervals of said lubricant holding parts change depending on the positions thereof with respect to the longitudinal direction.
9. A fixing device according to claim 6 , wherein said opposing surface is seen from said pressing roller side in a direction perpendicular to the feeding direction and perpendicular to a direction of said lubricant holding portion perpendicular to the feeding direction, each of areas of said lubricant holding parts is larger at an end portion than at a central portion with respect to the longitudinal direction and/or each of intervals of said lubricant holding parts in narrower at the end portion than at the central portion with respect to the longitudinal direction.
10. A fixing device according to claim 6 , wherein said lubricant at least contains base oil having a contact angle of 90° or less with respect to said heater holder, and
wherein each of the intervals of said lubricant holding parts is smaller than a diameter in which said base oil extends when said base oil in an amount held by one lubricant holding part is added dropwise to said opposing surface.
11. A fixing device according to claim 1 , wherein said lubricant holding portion comprises a recessed portion recessed in a direction in which said recessed portion is distant from said pressing roller.
12. An image forming apparatus comprising:
a photosensitive member on which an electrostatic latent image is formed;
developing means configured to develop the electrostatic latent image with toner to form a toner image;
transfer means configured to transfer the toner image onto a recording material; and
a fixing device according to claim 1 , configured to fix the toner image carried by the recording material.