US 10,372,069 B2Granted

Image forming apparatus having a control portion capable of controlling a rotation speed of a pair of conveyance members

AssigneeCanon Kabushiki Kaisha

InventorsKentaro Yamana, Yuichi Tanabe

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Abstract

An image forming apparatus includes a control portion that controls a drive speed of a first drive source, so that a speed of a sheet conveyed in a conveyance nip portion is greater than a speed of the sheet conveyed in a transfer nip portion, and a drive speed of a second drive source, so that the speed of the sheet conveyed in the transfer nip portion is greater than a speed of the sheet conveyed in a fixing nip portion. The control portion changes a rotation speed of a pair of conveyance members from a first speed to a second speed greater than the first speed after a first loop amount of the sheet formed between the transfer nip portion and the fixing nip portion becomes greater than a second loop amount of the sheet formed between the transfer nip portion and the conveyance nip portion.

Claims16

Dependent claims

An image forming apparatus comprising:

a movable endless belt;
a toner image forming unit configured to form a toner image on the belt;
a transfer rotary member forming a transfer nip portion with the belt, and configured to transfer the toner image, formed on the belt, onto a recording material;
a pair of conveyance members arranged upstream of the transfer nip portion in a conveyance direction of the recording material, and configured to convey the recording material to the transfer nip portion, the pair of conveyance members forming a conveyance nip portion;
a first drive source configured to drive at least one of the pair of conveyance members;
a pair of fixing members arranged downstream of the transfer nip portion in the conveyance direction of the recording material, and configured to fix the toner image, which has been transferred onto the recording material in the transfer nip portion, onto the recording material, the pair of fixing members forming a fixing nip portion;
a second drive source configured to drive at least one of the pair of fixing members;
and
a control portion configured to control:
(a) a drive speed of the first drive source, so that a speed of the recording material conveyed in the conveyance nip portion is greater than a speed of the recording material conveyed in the transfer nip portion;
and
(b) a drive speed of the second drive source, so that the speed of the recording material conveyed in the transfer nip portion is greater than a speed of the recording material conveyed in the fixing nip portion,
wherein the control portion changes a rotation speed of the pair of conveyance members from a first speed to a second speed greater than the first speed after a first loop amount of the recording material, formed between the transfer nip portion and the fixing nip portion, becomes greater than a second loop amount of the recording material, formed between the transfer nip portion and the conveyance nip portion.

10 more elements

An image forming apparatus comprising:

a movable endless belt;
a toner image forming unit configured to form a toner image on the belt;
a transfer rotary member forming a transfer nip portion with the belt, and configured to transfer the toner image, formed on the belt, onto a recording material at the transfer nip portion;
a pair of conveyance members arranged upstream of the transfer nip portion in a conveyance direction of the recording material, and configured to form a conveyance nip portion for conveying the recording material to the transfer nip portion;
a first drive source configured to drive at least one of the pair of conveyance members;
a pair of fixing members arranged downstream of the transfer nip portion in the conveyance direction of the recording material, and configured to form a fixing nip portion for fixing the toner image, which has been transferred onto the recording material in the transfer nip portion, onto the recording material;
a second drive source configured to drive at least one of the pair of fixing members;
an input portion configured to input information regarding a weight per unit area of the the recording material;
and
a control portion configured to control:
(a) a drive speed of the first drive source, so that a speed of the recording material conveyed in the conveyance nip portion is greater than a speed of the recording material conveyed in the transfer nip portion;
and
(b) a drive speed of the second drive source, so that the speed of the recording material conveyed in the transfer nip portion is greater than a speed of the recording material conveyed in the fixing nip portion,
wherein the control portion controls the drive speed of the first drive source to a first predetermined speed in at least a portion of a period of time from a time when a leading edge of the recording material reaches the fixing nip portion to a time when a trailing edge of the recording material reaches the conveyance portion, in a case in which the input information indicates that the weight per unit area of the recording material is a first weight per unit area,
wherein the control portion controls the drive speed of the first drive source to a second predetermined speed that is greater than the first predetermined speed in at least a portion of the period of time from the time when the leading edge of the recording material reaches the fixing nip portion to the time when the trailing edge of the recording material reaches the conveyance portion, in a case the input information indicates the weight per unit area of the recording material is a second weight per unit area that is greater than the first weight per unit area, and
wherein the first predetermined speed and the second predetermined speed are greater than the drive speed of the first drive source in a period of time from a time when the pair of conveyance members starts to convey the recording material to a time when the leading edge of the recording material reaches the fixing nip portion.

13 more elements

An image forming apparatus comprising:

a movable endless belt;
a toner image forming unit configured to form a toner image on the belt;
a transfer rotary member forming a transfer nip portion with the belt, and configured to transfer the toner image, formed on the belt, onto a recording material at the transfer nip portion;
a pair of conveyance members arranged upstream of the transfer nip portion in a conveyance direction of the recording material, and configured to form a conveyance nip portion for conveying the recording material to the transfer nip portion;
a first drive source configured to drive at least one of the pair of conveyance members;
a pair of fixing members arranged downstream of the transfer nip portion in the conveyance direction of the recording material, and configured to form a fixing nip portion for fixing the toner image, which has been transferred onto the recording material in the transfer nip portion, onto the recording material;
a second drive source configured to drive at least one of the pair of fixing members;
and
a control portion configured to control:
(a) a drive speed of the first drive source, so that a speed of the recording material conveyed in the conveyance nip portion is greater than a speed of the recording material conveyed in the transfer nip portion;
and
(b) a drive speed of the second drive source, so that the speed of the recording material conveyed in the transfer nip portion is greater than a speed of the recording material conveyed in the fixing nip portion,
wherein the control portion controls the drive speed of the first drive source to a predetermined speed in at least a portion of a first period of time from a time when a leading edge of the recording material reaches the fixing nip portion to a time when a trailing edge of the recording material reaches the conveyance portion, the predetermined speed being greater than the drive speed of the first drive source in a second period of time from a time when the pair of conveyance members starts to convey the recording material to a time when the leading edge of the recording material reaches the fixing nip portion.

10 more elements

Dependencies are inferred from the claim text.

Facts

Application: 15/212,351Filed 18 Jul 2016
Priority: JP 2015-1561766 Aug 2015
Published: US 2017/0038714 A19 Feb 2017
Granted: 6 Aug 2019
Term ends: Not estimatedThe source records don’t support an estimate.

Classification10 codes

G03G 15/2053
Using contact heat: structural details of heat elements, e.g. structure of roller or belt, eddy current, induction heating
G03G 15/1615
Using at least one intermediate support: relating to the driving mechanism for the intermediate support, e.g. gears, couplings, belt tensioning
G03G 15/167
By introducing the second base in the nip formed by the recording member and at least one transfer member, e.g. in combination with bias or heat:…
G03G 15/2017
Using contact heat: structural details of the fixing unit in general, e.g. cooling means, heat shielding means

Family

US 2017/0038714 A1Pre-grant publication · published 9 Feb 2017
US 10,372,069 B2This patent

From the US filing history. Foreign family members aren’t listed.

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