Image forming method and apparatus therefor

Claim 2

An image forming method using an image forming apparatus comprising: a rotary image carrier, and a rotary intermediate transfer medium arranged in pressure-contact with said image carrier, wherein at least one of said image carrier and said intermediate transfer medium is a belt-shape rotary body which is looped over a group of rolls and can circulate with at least one of said rolls as a drive transmission roll, and the peripheral length of said belt-shape rotary body is m (m: integer)-times as long as the peripheral length of said drive transmission roll, comprising the steps of: a toner image forming step of rotating said image carrier at a constant peripheral speed to form a toner image successively for each color component on said image carrier; a toner image intermediate transfer step of rotating said intermediate transfer medium at a constant peripheral speed different from the constant peripheral speed of said image carrier, on condition that one revolution time of said intermediate transfer medium is n (n: integer or 1/integer)-times as long as one revolution time of said image carrier, to transfer the toner image for each color component carried on said image carrier; and a toner image final transfer step of collectively transferring the toner image for each color transferred on said intermediate transfer medium onto a recording medium.

Claim 3

An image forming apparatus comprising: a rotary image carrier, an intermediate transfer medium in pressure-contact with said image carrier, a multi-color toner image forming means for successively forming a toner image for each color by a predetermined image forming process on said image carrier, a primary transfer means for successively transferring the toner image for each color carried on said image carrier to said intermediate transfer medium, and a secondary transfer means for collectively transferring the toner image for each color multiply transferred on said intermediate transfer medium onto a recording medium, at least one of said image carrier and said intermediate transfer medium being a belt-shape rotary body which is looped over a group of rolls and can circulate at least one of said rolls as a drive transmission roll, an image carrier driving means for driving said image carrier at a constant peripheral speed; and an intermediate transfer medium driving means for rotatively driving said intermediate transfer medium at a constant peripheral speed different from the constant peripheral speed of said image carrier so as to satisfy the condition that one revolution time of said intermediate transfer medium is n (n: integer or 1/integer)-times as long as one revolution time of said image carrier.

Claim 4

An image forming apparatus comprising: a rotary image carrier, an intermediate transfer medium in pressure-contact with said image carrier, a multi-color toner image forming means for successively forming a toner image for each color by a predetermined image forming process on said image carrier, a primary transfer means for successively transferring the toner image for each color carried on said image carrier to said intermediate transfer medium, and a secondary transfer means for collectively transferring the toner image for each color multiply transferred on said intermediate transfer medium onto a recording medium, at least one of said image carrier and said intermediate transfer medium being a belt-shape rotary body which is looped over a group of rolls and can circulate at least one of said rolls as a drive transmission roll, an image carrier driving means for driving said image carrier at a constant peripheral speed; and an intermediate transfer medium driving means for rotatively driving said intermediate transfer medium at a constant peripheral speed different from the constant peripheral speed of said image carrier so as to satisfy the condition that one revolution time of said intermediate transfer medium is n (n: integer or 1/integer)-times as long as one revolution time of said image carrier.

Claim 5

The image forming apparatus of claim 2, wherein said drive transmission roll has a larger contact area with said belt-shape rotary body than the contact area of other rolls in the group of rolls.

Claim 6

The image forming apparatus of claim 2, wherein said drive transmission roll of said belt shape rotary body is located at a position where there is a large change in the load for said belt-shape rotary body.

Claim 7

The image forming apparatus of claim 2, wherein after the primary transfer step of transferring the toner image of a final color from said image carrier to said intermediate transfer medium has been completed, the peripheral speed of said intermediate transfer medium is varied.

Claim 8

An image forming apparatus comprising: a rotary image carrier, an intermediate transfer medium in pressure-contact with said image carrier, a multi-color toner image forming means for successively forming a toner image for each color by a predetermined image forming process on said image carrier, a primary transfer means for successively transferring the toner image for each color carried on said image carrier to said intermediate transfer medium, and a secondary transfer means for collectively transferring the toner image for each color multiply transferred on said intermediate transfer medium, one of said image carrier and said intermediate transfer medium being a drum-shape rotary body and the other being a belt-shape rotary body which is looped over a group of rolls and can circulate at least one of said rolls as a drive transmission roll, an image carrier driving means for driving said image carrier at a constant peripheral speed; and an intermediate transfer medium driving means for driving said intermediate transfer medium at a constant peripheral speed different from the constant peripheral speed of said image carrier, wherein a peripheral length of said belt-shape rotary body is set so as to satisfy the following relationship equation: Lb=m·Lbr (m: integer) Lb/vb=n·Ld/vd (n=integer or 1/integer) where Lb: peripheral length of said belt-shape rotary body Lbr: peripheral length of said drive transmission roll Ld: peripheral length of said drum-shape rotary body vb: peripheral speed of said belt-shape rotary body vd: peripheral speed of said drum shape rotary body.

Claim 9

An image forming apparatus comprising: a rotary image carrier, an intermediate transfer medium in pressure-contact with said image carrier, a multi-color toner image forming means for successively forming a toner image for each color by a predetermined image forming process on said image carrier, a primary transfer means for successively transferring the toner image for each color carried on said image carrier to said intermediate transfer medium, and a secondary transfer means for collectively transferring the toner image for each color multiply transferred on said intermediate transfer medium, one of said image carrier and said intermediate transfer medium being a drum-shape rotary body and the other being a belt-shape rotary body which is looped over a group of rolls and can circulate at least one of said rolls as a drive transmission roll, an image carrier driving means for driving said image carrier at a constant peripheral speed; and an intermediate transfer medium driving means for driving said intermediate transfer medium at a constant peripheral speed different from the constant peripheral speed of said image carrier, wherein a peripheral length of said belt-shape rotary body is set so as to satisfy the following relationship equation: Lb=m·Lbr (m: integer) Lb/vb=n·Ld/vd (n=integer or 1/integer) where Lb: peripheral length of said belt-shape rotary body Lbr: peripheral length of said drive transmission roll Ld: peripheral length of said drum-shape rotary body vb: peripheral speed of said belt-shape rotary body vd: peripheral speed of said drum shape rotary body.

Claim 10

An image forming apparatus comprising: a rotary image carrier, an intermediate transfer medium in pressure-contact with said image carrier, a multi-color toner image forming means for successively forming a toner image for each color by a predetermined image forming process on said image carrier, a primary transfer means for successively transferring the toner image for each color carried on said image carrier to said intermediate transfer medium, and a secondary transfer means for collectively transferring the toner image for each color multiply transferred on said intermediate transfer medium to a recording medium, both of said image carrier and said intermediate transfer medium being belt-shape rotary bodies each of which is looped over a group of rolls and can circulate with at least one of said rolls as a drive transmission roll, an image carrier driving means for driving said image carrier at a constant peripheral speed; and an intermediate transfer medium driving means for rotatively driving said intermediate transfer medium at a constant peripheral speed different from that of said image carrier, wherein the peripheral length of said belt-shape rotary body of each of said image carrier and said intermediate transfer medium is set so as to satisfy the following relationship equation: Lb1=m1·Lbr1 (m1: integer) Lb2=m2·Lbr2 (m2: integer) Lb1/vb1=n·Lb2/vb2 (n=integer or 1/integer) where Lb1: peripheral length of said belt-shape rotary body of said image carrier Lbr1: peripheral length of said drive transmission roll of said image carrier Lb2: peripheral length of said belt-shape rotary body of said intermediate transfer medium Lbr2: peripheral length of said drive transmission roll of said intermediate transfer medium vb1: peripheral speed of said belt-shape rotary body (=Vp) of said image carrier vb2: peripheral speed of said belt-shape rotary body (=Vm) of said intermediate transfer medium.

Claim 11

An image forming apparatus comprising: a rotary image carrier, an intermediate transfer medium in pressure-contact with said image carrier, a multi-color toner image forming means for successively forming a toner image for each color by a predetermined image forming process on said image carrier, a primary transfer means for successively transferring the toner image for each color carried on said image carrier to said intermediate transfer medium, and a secondary transfer means for collectively transferring the toner image for each color multiply transferred on said intermediate transfer medium to a recording medium, both of said image carrier and said intermediate transfer medium being belt-shape rotary bodies each of which is looped over a group of rolls and can circulate with at least one of said rolls as a drive transmission roll, an image carrier driving means for driving said image carrier at a constant peripheral speed; and an intermediate transfer medium driving means for rotatively driving said intermediate transfer medium at a constant peripheral speed different from that of said image carrier, wherein the peripheral length of said belt-shape rotary body of each of said image carrier and said intermediate transfer medium is set so as to satisfy the following relationship equation: Lb1=m1·Lbr1 (m1: integer) Lb2=m2·Lbr2 (m2: integer) Lb1/vb1=n·Lb2/vb2 (n=integer or 1/integer) where Lb1: peripheral length of said belt-shape rotary body of said image carrier Lbr1: peripheral length of said drive transmission roll of said image carrier Lb2: peripheral length of said belt-shape rotary body of said intermediate transfer medium Lbr2: peripheral length of said drive transmission roll of said intermediate transfer medium vb1: peripheral speed of said belt-shape rotary body (=Vp) of said image carrier vb2: peripheral speed of said belt-shape rotary body (=Vm) of said intermediate transfer medium.

Claim 12

An image forming method using an image forming apparatus comprising: a rotary image carrier, and a rotary intermediate transfer medium arranged in pressure-contact with said image carrier, comprising the steps of: a toner image forming step of rotating said image carrier at a constant peripheral speed to form a toner image successively for each color component on said image carrier; a toner image intermediate transfer step of rotating said intermediate transfer medium at a constant peripheral speed different from the constant peripheral speed of said image carrier, on condition that one revolution time of said intermediate transfer medium is n (n: integer or 1/integer)-times as long as one revolution time of said image carrier, to transfer the toner image for each color component carried on said image carrier onto said intermediate transfer medium; and a toner image final transfer step of collectively transferring the toner image for each color transferred on said intermediate transfer medium onto a recording medium.

Claim 13

An image forming method using an image forming apparatus comprising: a rotary image carrier, and a rotary intermediate transfer medium arranged in pressure-contact with said image carrier, comprising the steps of: a toner image forming step of rotating said image carrier at a constant peripheral speed to form a toner image successively for each color component on said image carrier; a toner image intermediate transfer step of rotating said intermediate transfer medium at a constant peripheral speed different from the constant peripheral speed of said image carrier, on condition that one revolution time of said intermediate transfer medium is n (n: integer or 1/integer)-times as long as one revolution time of said image carrier, to transfer the toner image for each color component carried on said image carrier onto said intermediate transfer medium; and a toner image final transfer step of collectively transferring the toner image for each color transferred on said intermediate transfer medium onto a recording medium.

Claim 14

An image forming apparatus comprising: a rotary image carrier, an intermediate transfer medium in pressure-contact with said image carrier, a multi-color toner image forming means for successively forming a toner image for each color by a predetermined image forming process on said image carrier, a primary transfer means for successively transferring the toner image for each color carried on said image carrier to said intermediate transfer medium, and a secondary transfer means for collectively transferring the toner image for each color multiply transferred on said intermediate transfer medium onto a recording medium, an image carrier driving means for driving said image carrier at a constant peripheral speed; and an intermediate transfer medium driving means for driving said intermediate transfer medium at a constant peripheral speed different from the constant peripheral speed of said image carrier so as to satisfy the condition that one revolution time of said intermediate transfer medium is n (n: integer or 1/integer)-times as long as one revolution time of said image carrier.

Claim 15

An image forming apparatus comprising: a rotary image carrier, an intermediate transfer medium in pressure-contact with said image carrier, a multi-color toner image forming means for successively forming a toner image for each color by a predetermined image forming process on said image carrier, a primary transfer means for successively transferring the toner image for each color carried on said image carrier to said intermediate transfer medium, and a secondary transfer means for collectively transferring the toner image for each color multiply transferred on said intermediate transfer medium onto a recording medium, an image carrier driving means for driving said image carrier at a constant peripheral speed; and an intermediate transfer medium driving means for driving said intermediate transfer medium at a constant peripheral speed different from the constant peripheral speed of said image carrier so as to satisfy the condition that one revolution time of said intermediate transfer medium is n (n: integer or 1/integer)-times as long as one revolution time of said image carrier.