Image forming apparatus with changeable feed interval for continuous feed

Claim 2

An image forming apparatus comprising: means for fixing an unfixed image on a recording material, said fixing means comprising a heating member selectively maintainable at one of at least a first set temperature and a second set temperature lower than the first set temperature during fixing, and a backup member forming a nip with said heating member so that said nip conveys a recording material holding an unfixed image thereon through said nip to fix the unfixed image; feed means for continuously feeding recording materials on which there is an unfixed image to said fixing means; and feed interval control means for switching between a first feed interval at the first set temperature and a second feed interval shorter than the first feed interval at the second set temperature during continuous feeding of the recording materials.

Claim 3

An apparatus according to claim 1, wherein said heating member comprises a heating roller heated by a heater and supported by bearings made of a resin.

Claim 4

An apparatus according to claim 1, wherein said fixing means further comprises a temperature detection element for detecting the surface temperature of said heating member, said temperature detection element being provided within a passage region of a recording material.

Claim 5

An apparatus according to claim 3, wherein said temperature detection element is provided adjacent a reference position for passage of recording materials.

Claim 6

An apparatus according to claim 1, wherein said fixing means maintains the temperature of said heating member so that said first set temperature is higher than said second set temperature for a predetermined time after a power source of the apparatus body is turned on.

Claim 7

An image forming apparatus comprising: a heating member for fixing; temperature control means for maintaining said heating member at a predetermined set temperature during fixing; a backup member forming a nip with said heating member to convey a recording material holding an unfixed image through said nip to fix the unfixed image; feed means for continuously feeding recording materials at intervals to said nip for fixing an unfixed image on each of said recording materials; size detection means for detecting a size of the recording material; and feed interval control means for controlling the feed interval of said recording materials on the basis of the results of detection by said size detection means; wherein said feed interval control means makes the feed interval longer when said size detection means detects that a recording material has a small passage region in said nip.

Claim 8

An image forming apparatus comprising: a heating member for fixing; temperature control means for maintaining said heating member at a predetermined set temperature during fixing; a backup member forming a nip with said heating member to convey a recording material holding an unfixed image through said nip to fix the unfixed image; feed means for continuously feeding recording materials at intervals to said nip for fixing an unfixed image on each of said recording materials; size detection means for detecting a size of the recording material; and feed interval control means for controlling the feed interval of said recording materials on the basis of the results of detection by said size detection means; wherein said feed interval control means makes the feed interval longer when said size detection means detects that a recording material has a small passage region in said nip.

Claim 9

An apparatus according to claim 6, wherein said heating member comprises a heating roller heated by a heater and supported by bearings made of a resin.

Claim 10

An apparatus according to claim 6, wherein said temperature control means further comprises a temperature detection element for detecting the surface temperature of said heating member, said temperature detection element being provided within a passage region of a recording material.

Claim 11

An apparatus according to claim 8, wherein said temperature detection element is provided adjacent a reference position for passage of recording materials.

Claim 12

An apparatus according to claim 6, wherein a smaller size recording material is an envelope.