# US 2021/0397111 A1 · Image forming apparatus

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- Number: US 2021/0397111 A1
- Document ID: US20210397111A1
- Status: Published application
- Kind: A1
- Application number: 17/337,585
- Filed: 2021-06-03
- Published: 2021-12-23
- Earliest claimed: 2020-06-18
- Assignees: Canon Kabushiki Kaisha
- Applicants: Canon Kabushiki Kaisha
- Inventors: Tomoya Inuzuka
- Web page: https://patentgrep.com/patent/US20210397111A1

## CPC

- G03G 15/6558: {Feeding path after the copy sheet preparation and up to the transfer point, e.g. registering; Deskewing; Correct timing of sheet feeding to the transfer point}
- G03G 15/1605: {using at least one intermediate support (G03G15/1625 takes precedence)}
- G03G 15/1615: {relating to the driving mechanism for the intermediate support, e.g. gears, couplings, belt tensioning}
- G03G 15/6564: {with correct timing of sheet feeding}
- G03G 15/06: for developing
- G03G 15/16: of a toner pattern, e.g. a powder pattern {, e.g. magnetic transfer}
- G03G 2215/00409: Transfer device
- G03G 2215/00481: Thick
- G03G 2215/00485: Thin
- G03G 2215/00556: Control of copy medium feeding
- G03G 2215/00599: Timing, synchronisation
- G03G 2215/00603: Control of other part of the apparatus according to the state of copy medium feeding
- G03G 2215/00738: of sheet thickness or rigidity
- G03G 2215/00949: Copy material feeding speed switched according to current mode of the apparatus, e.g. colour mode
- G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY

## Abstract

An image forming apparatus includes an image bearing member, an image forming portion, an endless belt, a plurality of stretching rollers including an inner roller, an outer roller, a position changing mechanism capable of changing a position of the inner roller to a first position and a second position positioned downstream of the first position with respect to a rotational direction of the endless belt, a feeding member, a feeding member driving portion, and a controller. A feeding start timing of a recording material by the feeding member depends on the position of the inner roller during transfer of a toner image onto the recording material.

## Claims

### Claim 1

An image forming apparatus comprising:
an image bearing member configured to bear a toner image;
an image forming portion configured to form the toner image on said image bearing member;
an endless belt onto which the toner image formed on said image bearing member is transferred at a primary transfer portion;
a plurality of stretching rollers including an inner roller and configured to stretch said endless belt;
an outer roller configured to form a secondary transfer portion, in cooperation with said inner roller, where the toner image is transferred from said endless belt onto a recording material;
a position changing mechanism configured to change a position of the secondary transfer portion with respect to a circumferential direction of said inner roller by moving said inner roller,
wherein said position changing mechanism is capable of changing a position of said inner roller to a plurality of positions including a first position and a second position positioned downstream of the first position with respect to a rotational direction of said endless belt;
a feeding member configured to feed the recording material to the secondary transfer portion;
a feeding member driving portion configured to drive said feeding member; and
a controller configured to control a feeding start timing of the recording material by said feeding member,
wherein the feeding start timing of the recording material by said feeding member depends on the position of said inner roller during transfer of the toner image onto the recording material.

### Claim 2 (depends on 1)

An image forming apparatus according to claim 1, wherein on the basis of information on a kind of the recording material, said controller controls the position of said inner roller during the transfer of the recording material onto the recording material and the feeding start timing of the recording material by said feeding member.

### Claim 3 (depends on 1)

An image forming apparatus according to claim 1, wherein said stretching rollers includes a downstream roller provided downstream of and adjacent to said inner roller with respect to the rotational direction of said endless belt,
wherein when a length of said endless belt in a circumferential direction stretched between said inner roller and said downstream roller is Ld which is Ld1 in a case that said inner roller is in the first position and which is Ld2 in a case that said inner roller is in the second position, Ld1 being longer than Ld2, and
wherein said controller controls the feeding start timing of the recording material by said feeding member so that the feeding start timing in a case that the toner image is transferred in a state in which said inner roller is in the first position is later than the feeding start timing in a case that the toner image is transferred in a state in which said inner roller is in the second position.

### Claim 4 (depends on 3)

An image forming apparatus according to claim 3, wherein said stretching rollers includes a tension roller provided downstream of the primary transfer portion and upstream of said inner roller with respect to the rotational direction of said endless belt and imparting tension to said endless belt.

### Claim 5 (depends on 1)

An image forming apparatus according to claim 1, wherein in a case that the toner image is transferred onto the recording material in a state in which said inner roller is in the first position, a time from a predetermined reference timing with respect to a driving speed of said endless belt during the transfer until the feeding start timing of the recording material by said feeding member is a first predetermined value, and
in a case that the toner image is transferred onto the recording material in a state in which said inner roller is in the second position, the time is a second predetermined value different from the first predetermined value.

### Claim 6 (depends on 1)

An image forming apparatus according to claim 1, wherein on the basis of a kind of the recording material, said controller changes a time from a predetermined reference timing with respect to a driving speed of said endless belt during transfer of the toner image onto the recording material until the feeding start timing of the recording material by said feeding member, depending on the position of said inner roller.

### Claim 7 (depends on 1)

An image forming apparatus according to claim 1, wherein said controller controls the feeding start timing of the recording material by said feeding member so that a registration deviation amount occurring with a change in position of said inner roller is small or zero.

### Claim 8 (depends on 1)

An image forming apparatus according to claim 1, wherein said stretching rollers includes an upstream roller provided upstream of and adjacent to said inner roller with respect to the rotational direction of said endless belt, and
wherein in a cross section substantially perpendicular to a rotational direction of said inner roller,
a common tangential line between said inner roller and said upstream roller on a side where said endless belt is stretched is a reference line L1,
a rectilinear line passing through a rotation center of said inner roller and substantially perpendicular to the reference line L1 is an inner roller center line L2,
a rectilinear line passing through a rotational center of said outer roller and substantially perpendicular to the reference line L1 is an outer roller center line L3, and
a distance between the inner roller center line L2 and the outer roller center line L3 is an offset amount X which is a positive value when the outer roller center line L3 is positioned upstream of the inner roller center line L2 with respect to the rotational direction of said endless belt, and
wherein said position changing mechanism changes the offset amount X between a first offset amount X1 in a case of the first position and a second offset amount X2 in a case of the second position, the first offset amount X1 being a positive value and the second offset amount X2 being zero or a negative value.

### Claim 9 (depends on 1)

An image forming apparatus according to claim 1, wherein said outer roller contacts an outer peripheral surface of said endless belt via another endless belt stretched by said outer roller and another roller.

### Claim 10 (depends on 1)

An image forming apparatus according to claim 1, further comprising a guiding member provided upstream of the secondary transfer portion with respect to a recording material feeding direction and configured to guide the recording material to the secondary transfer portion.