Color image forming apparatus spacially separating toner image heat-fusion from toner image transfer to a recording medium

A color image forming apparatus comprising:

• an image carrying body supported in such a manner that a toner image forming surface thereof is allowed to circulate;
• image forming means for forming a multi-color toner image on said image carrying body by sequentially superimposing toner images in respective colors;
• heating means for heat-fusing the multi-color toner image on said image carrying body;
• and
• pressing means for pressing said image carrying body from the toner image surface side, wherein:
• the multi-color toner image heat-fused is fixed upon transfer onto a recording material transported to a pressing position of said pressing means against said image carrying body;
• the pressing position of said pressing means against said image carrying body is provided spaced apart from a heating position at which said heating means heat-fuses the multi-color toner image;
• and
• when L1 is a heating length of said heating means in a circulation direction of said image carrying body at the heating position, and L2 is a pressing length of said image carrying body against the recording material in the circulation direction thereof at the pressing position, then said heating means is set to satisfy:
• L2×10>L1>L2×2.

A color image forming apparatus comprising:

• an image carrying body supported in such a manner that a toner image forming surface thereof is allowed to circulate;
• image forming means for forming a multi-color toner image on said image carrying body by sequentially superimposing toner images in respective colors;
• heating means for heat-fusing the multi-color toner image on said image carrying body;
• and
• pressing means for pressing said image carrying body from the toner image surface side, wherein:
• the multi-color toner image heat-fused is fixed upon transfer onto a recording material transported to a pressing position of said pressing means against said image carrying body;
• the pressing position of said pressing means against said image carrying body is provided spaced apart from a heating position at which said heating means heat-fuses the multi-color toner image;
• and
• said pressing means includes a fixing roller and a pressing roller, said fixing roller being composed of a metallic column whose surface is coated with foam silicone rubber, said pressing roller being composed of a metallic drum whose surface is coated with fluoride resin.

A color image forming apparatus comprising:

• an image carrying body supported in such a manner that a toner image forming surface thereof is allowed to circulate;
• image forming means for forming a multi-color toner image on said image carrying body by sequentially superimposing toner images in respective colors;
• heating means for heat-fusing the multi-color toner image on said image carrying body;
• and
• pressing means for pressing said image carrying body from the toner image surface side, wherein:
• the multi-color toner image heat-fused is fixed upon transfer onto a recording material transported to a pressing position of said pressing means against said image carrying body;
• the pressing position of said pressing means against said image carrying body is provided spaced apart from a heating position at which said heating means heat-fuses the multi-color toner image;
• said image carrying body has an image carrying belt bridged across at least two rollers;
• said heating means is provided at an end of an inner circumferential surface of said image carrying belt;
• and
• said heating means is provided between the pressing position and one of said at least two rollers across which said image carrying belt is bridged in such a manner as to slide along the inner circumferential surface of said image carrying belt.

A color image forming apparatus comprising:

• an image carrying body supported in such a manner that a toner image forming surface thereof is allowed to circulate;
• image forming means for forming a multi-color toner image on said image carrying body by sequentially superimposing toner images in respective colors;
• heating means for heat-fusing the multi-color toner image on said image carrying body;
• and
• pressing means for pressing said image carrying body from the toner image surface side, wherein:
• the multi-color toner image heat-fused is fixed upon transfer onto a recording material transported to a pressing position of said pressing means against said image carrying body;
• the pressing position of said pressing means against said image carrying body is provided spaced apart from a heating position at which said heating means heat-fuses the multi-color toner image;
• said image carrying body has an image carrying belt bridged across at least two rollers;
• said heating means is provided at an end of an inner circumferential surface of said image carrying belt;
• and
• said heating means is a heating roller, said heating roller being one of said rollers across which said image carrying belt is bridged and provided at an upstream end of said pressing position of said pressing means against said image carrying belt.

A color image forming apparatus comprising:

• an image carrying body supported in such a manner that a toner image forming surface thereof is allowed to circulate;
• image forming means for forming a multi-color toner image on said image carrying body by sequentially superimposing toner images in respective colors;
• heating means for heat-fusing the multi-color toner image on said image carrying body;
• and
• pressing means for pressing said image carrying body from the toner image surface side, wherein:
• the multi-color toner image heat-fused is fixed upon transfer onto a recording material transported to a pressing position of said pressing means against said image carrying body;
• the pressing position of said pressing means against said image carrying body is provided spaced apart from a heating position at which said heating means heat-fuses the multi-color toner image;
• and
• when T1 is a temperature of an interface between toner and the recording material when the toner image is fixed onto the recording material upon transfer, and T2 is a temperature of the toner when viscosity of the toner is set to a value that can attain sufficient fixing strength, said heating means heats the toner image and said image carrying body to satisfy:
• T1>>T2.

A color image forming apparatus comprising:

• an image carrying body supported in such a manner that a toner image forming surface thereof is allowed to circulate;
• image forming means for forming a multi-color toner image on said image carrying body by sequentially superimposing toner images in respective colors;
• heating means for heat-fusing the multi-color toner image on said image carrying body;
• and
• pressing means for pressing said image carrying body from the toner image surface side, wherein:
• the multi-color toner image heat-fused is fixed upon transfer onto a recording material transported to a pressing position of said pressing means against said image carrying body;
• the pressing position of said pressing means against said image carrying body is provided spaced apart from a heating position at which said heating means heat-fuses the multi-color toner image;
• and
• when T3 is a softening point temperature of toner and T4 is a temperature of the toner right before the toner image is fixed onto the recording material upon transfer, then said heating means heats the toner image and said image carrying body to satisfy:
• T4−T3>>60° (C.).