Sheet conveying device, image forming apparatus

A sheet conveying device comprising:

• a first pair of rollers configured to convey a sheet on a conveyance path that passes an image forming portion that forms an image on the sheet;
• a first driving motor configured to rotationally drive at least one roller of the first pair of rollers;
• a first speed detecting portion configured to detect a speed related to a sheet conveyance speed of the first pair of rollers;
• a second pair of rollers configured to convey the sheet on the conveyance path together with the first pair of rollers;
• a second driving motor configured to rotationally drive at least one roller of the second pair of rollers;
• a second speed detecting portion configured to detect a speed related to a sheet conveyance speed of the second pair of rollers;
• a speed difference calculating portion configured to calculate a speed difference between a first detected speed detected by the first speed detecting portion and a second detected speed detected by the second speed detecting portion;
• a motor control portion configured to determine target speeds respectively for the first driving motor and the second driving motor based on the speed difference calculated by the speed difference calculating portion, and performs a control during a non-image formation period so that driving speeds of the first driving motor and the second driving motor respectively become the target speeds for the first driving motor and the second driving motor;
• and
• a storage portion configured to store, in advance, correspondence between each possible value of the speed difference that may be calculated by the speed difference calculating portion, and correction amounts for duty cycles of PWM signals that are output to the first driving motor and the second driving motor, wherein
• when the speed difference is calculated by the speed difference calculating portion, the motor control portion reads correction amounts for duty cycles of PWM signals for the first driving motor and the second driving motor that correspond to a value of the speed difference calculated by the speed difference calculating portion, and drives the first driving motor and the second driving motor by PWM signals corrected by the correction amounts read from the storage portion.