US Patent No. 9,829,833

IMAGE FORMING APPARATUS THAT SETS SPEEDS OF DRIVING SOURCES


Patent No. 9,829,833
Issue Date November 28, 2017
Title Image Forming Apparatus That Sets Speeds Of Driving Sources
Inventorship Tadashi Iwakawa, Iwakawa (JP)
Koichi Taniguchi, Tokyo (JP)
Takuya Matsumura, Kashiwa (JP)
Assignee Canon Kabushiki Kaisha, Tokyo (JP)

Claim of US Patent No. 9,829,833

1. An image forming apparatus comprising:
a rotatable image bearing member for bearing a toner image;
a toner image forming portion configured to form the toner image on said image bearing member;
a rotatable intermediary transfer member, contacting said image bearing member at a transfer portion, and configured to carry
the toner image transferred from said image bearing member at the transfer portion and then to be transferred onto a recording
material;

a first driving motor configured to rotationally drive said image bearing member;
a second driving motor configured to drive said intermediary transfer member;
a detecting portion configured to detect information on an output torque of said first driving motor or said second driving
motor;

a changing portion configured to change a speed instruction value of each of driving speeds of said first driving motor and
said second driving motor;

an executing portion configured to execute an operation in a detecting mode in which information on the output torque of another
driving motor corresponding to the speed instruction value of one driving motor is detected while driving said first driving
motor and said second driving motor in a period other than during image formation, wherein the detecting mode includes a first
detection period in which a state relating to a frictional force between said image bearing member and said intermediary transfer
member at the transfer portion is set at a first state and then the detection is made, and includes a second detection period
in which the state is set at a second state greater in the frictional force than in the first state and then the detection
is made, wherein in each of the first and second detection periods, the speed instruction value of the other driving motor
is set at a fixed value, wherein in the first detection period the speed instruction value of the one driving motor is successively
changed to a plurality of different values and information on plural output torque values of the one driving motor corresponding
to the different speed instruction values is successively detected, and wherein in the second detection period the speed instruction
value of the one driving motor is successively changed to a plurality of different values and information on plural output
torque values of the one driving motor corresponding to the plurality of different speed instruction values is successively
detected; and

a setting portion configured to set the speed instruction value of the one driving motor to be used during the image formation
on the basis of the information on plural output torque values detected in the first detection period and the information
on plural output torque values detected in the second detection period.