JP2015146728A5 - DRIVE DEVICE, CONVEYING DEVICE, AND IMAGE FORMING DEVICE - Google Patents

Description

The present invention, DC motors drive operated device that controls the drive of, and, to a conveyance apparatus and an image forming apparatus Ru with drive kinematic device that written.

The present invention has been made in consideration of the above background, and has as its object to provide a following drive operated device, conveyance device and an image forming apparatus. That is, motor instability of the rotation, and the driven member speed destabilization can be that drive operated device to suppress the like due to load fluctuations due to mixing of noise into the rotation sensing signal.

In order to achieve the above object, the invention of claim 1 is a drive device, which is attached to a DC motor for rotating a motor shaft and the DC motor main body, and is arranged around the motor shaft of the DC motor. A board, a code wheel attached to a position on the shaft tip side of a position on the DC motor main body side and a position on the shaft tip side with respect to the substrate in the longitudinal direction of the motor shaft, and accompanying rotation of the motor shaft A Hall element that outputs a Hall signal, and the substrate reads a code wheel from a driver circuit that supplies an excitation voltage to the DC motor based on the Hall signal. A sensor for detecting the rotation amount of the motor shaft and outputting a rotation amount detection signal with a resolution higher than the resolution for detecting the rotation amount of the motor shaft. It is characterized in.

In the present invention, without detecting the speed of the driven body driven by the D C motors, to detect directly and accurately the rotational speed of the D C motors by sensors. In such a configuration, as compared with the prior art in which has been indirectly detecting a change in the rotational speed of the D C motors based on the speed change of the driven body, quickly detect the change in the rotational speed of the D C Motor Then, by quickly returning to the original rotational speed, speed instability of the driven body due to load fluctuation can be suppressed.

In the present invention, a substrate having a driver circuit that is mounted on D C motors, as compared with the driver circuit in the prior art which has been disposed at a position away from the D C motors, the driver circuit thus approximating the distance between D C motors coils and. Thus, the supply that without excitation voltage to the motor coil from the driver circuit by an electrode on the circuit board provided between the plurality of driving power supply lines or signal driver circuit harness a bundle of electric wires and D C motors And a rotation sensing signal can be transmitted from the DC motor to the driver circuit. As a result, by suppressing the generation of noise when switching the coil to be excited at high speed, or by suppressing the mixing of the generated noise into the rotation sensing signal, the motor caused by the mixing of noise into the rotation sensing signal Instability of rotation can be suppressed.

A code wheel 211a of a motor encoder 211 as a second rotation amount detection means is fixed at a position behind the driver board 216 in the motor shaft 213, and the same rotation as the motor shaft 213 is accompanied by the rotation of the motor shaft 213. Rotate on the axis. As shown in FIG. 9, the code wheel 211 a includes a plurality of slits SL arranged at a predetermined pitch in the rotation direction. An optical sensor 211b composed of a transmissive photosensor is fixed to the driver board 216 of the transport motor 210 so as to sequentially detect the slits SL as the code wheel 211a rotates (see FIG. 8). Although not shown for convenience, a cover member that covers the driver board 216 and the motor encoder 211 is fitted into the rear end portion of the motor body of the transport motor 210.

The position / speed tracking control circuit 202 calculates a deviation amount of the motor rotation speed signal sent from the motor rotation amount / speed calculation circuit 203 from the target speed signal, and adjusts the PWM signal based on the deviation amount. Thus, the excitation voltage for the conveyance motor 210 is adjusted, and a speed adjustment process for controlling the rotation speed of the conveyance motor 210 to the target rotation speed is performed. By this speed adjustment processing, the rotational speed of the first transport row r46a that is a driven body driven by the transport motor 210 can be freely adjusted. Such speed adjustment processing is performed by feedback control using PID control. The present invention can freely adjust the speed of the driven body driven by the DC brushless motor based on the result of detecting the rotational speed of the DC brushless motor as in this copying machine.

Claims (8)

  A driving device comprising:
A DC motor that rotates the motor shaft;
A substrate attached to the DC motor body and disposed around the motor shaft of the DC motor;
A code wheel attached to a position on the shaft tip side of the DC motor main body side and the shaft tip side of the substrate in the longitudinal direction of the motor shaft;
A hall element that outputs a hall signal as the motor shaft rotates,
By reading the code wheel and the driver circuit that supplies the excitation voltage to the DC motor based on the Hall signal, the substrate has a resolution higher than the resolution of detecting the rotation amount of the motor shaft based on the Hall signal. A driving device comprising: a sensor that detects a rotation amount of the motor shaft and outputs a rotation amount detection signal.   The drive device according to claim 1, further comprising a cover member that covers the substrate and the code wheel.   The drive device according to claim 1, wherein the motor shaft passes through the substrate.   The drive device according to any one of claims 1 to 3, wherein the sensor is an optical sensor, and the code wheel includes a plurality of slits.   5. The driving device according to claim 1, wherein the board includes a connector that performs electrical connection for transmitting the rotation amount detection signal. 6.   A drive system,
A drive system comprising: the drive device according to any one of claims 1 to 5; and a control circuit that receives the rotation amount detection signal.   A conveying device,
A transport apparatus comprising: the drive device according to claim 1; and a transport roller driven by the drive device.   An image forming apparatus,
6. A drive device according to claim 1, a transport unit that transports a recording sheet by a transport roller driven by the drive device, and an image forming unit that forms an image on the recording sheet. An image forming apparatus.