Image forming apparatus

Patent metadata

Field	Value
Publication number	US-10054894-B2
Application number	US-201715718932-A
Country	US
Kind code	B2
Filing date	Sep 28, 2017
Priority date	Oct 25, 2016
Publication date	Aug 21, 2018
Grant date	Aug 21, 2018

Abstract

An image forming apparatus that controls to cut off exciting currents supplied to a plurality of motors to drive conveyance roller pairs after a leading end of a paper sheet is brought in contact with a registration roller pair, and, when cutting off the exciting currents, cut off the exciting current for at least one of the motors at a different timing from the other motors.

First claim

What is claimed is:

1. An image forming apparatus, comprising:
a registration roller pair;
a loop roller pair that is disposed on an upstream side of the registration roller pair and further pushes a paper sheet brought in contact with the registration roller pair having stopped so as to form a loop on the paper sheet;
a plurality of conveyance roller pairs that are disposed on an upstream side of the loop roller pair;
a plurality of motors that are provided for the plurality of conveyance roller pairs so as to rotate the plurality of conveyance roller pairs; and
a processor that controls exciting currents to be supplied to the plurality of motors,
wherein after a leading end of the paper sheet is brought in contact with the registration roller pair, the processor controls to cut off the exciting currents supplied to the plurality of motors, and when cutting off the exciting currents, among the plurality of motors driving the plurality of conveyance roller pairs that are conveying the paper sheet, the processor cuts off the exciting current for at least one of the plurality of motors at a different timing from another motor of the plurality of motors.

2. The image forming apparatus according to claim 1 , wherein when cutting off the exciting currents, the processor cuts off the exciting currents in an order from the exciting current for the motor to drive the conveyance roller pair located on an upstream side to the exciting current for the motor to drive the conveyance roller pair located on an downstream side among the plurality of conveyance roller pairs being conveying the paper sheet.

3. The image forming apparatus according to claim 1 , wherein the processor selects an order of the motors for which the exciting currents are cut off, in accordance with a thickness and stiffness of a paper sheet.

4. The image forming apparatus according to claim 1 , wherein the processor cuts off the exciting current for at least one of the motors during a period when a rotation speed of each of the motors is decelerated after the paper sheet has been brought in contact with the registration roller pair.

5. The image forming apparatus according to claim 1 , wherein the processor detects counter electromotive force in at least one of the motors, and based on a detection result, the processor cuts off the exciting current for at least the other one of the plurality of motors.

6. The image forming apparatus according to claim 1 , wherein based on a conveyance speed and sheet length of the paper sheet, the processor control a timing at which the exciting currents for the motors are cut off and a conveyance speed after the motors have been restarted again after the exciting currents have been cut off.

7. The image forming apparatus according to claim 1 , wherein at least one of the conveyance roller pairs is disposed on a crooked conveyance pathway.

8. The image forming apparatus according to claim 1 , wherein the loop roller pair includes at least two roller pairs driven independently, which are disposed in a direction intersecting with a conveyance direction of the paper sheet.

Assignees

• Konica Minolta Inc

Inventors

• Mine Hidenori
• Izumiya Kenji
• Ogata Satoshi
• Tamaki Kenji
• Kodama Hirokatsu

Classifications

• B65H2515/704

  Operations & Transport · mapped topic

• B65H5/062

  between rollers or balls · CPC title

• B65H9/006

  the stop being formed by forwarding means in stand-by · CPC title

• G03G15/6561 Primary

  for sheet registration · CPC title

• B65H2403/92

  Electric drive · CPC title