JP2002091243A5 - Image forming device - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
The present invention is reliable by In the image forming apparatus automatically duplex, a roller for conveying the transfer sheet and driven by a single motor, the electromagnetic clutch is unnecessary while realizing cost reduction and miniaturization It relates to an image forming apparatus having improved properties.

0002.
[Conventional technology]
In the conventional model, the transfer paper is attached to the resist roller from the paper feed tray to correct the bending of the transfer paper, and after a certain period of time, the drive of the loop roller (first roller) is temporarily stopped when a predetermined loop is generated. Then, when the predetermined conditions are met, the resist roller and the loop roller are rotated to feed the transfer paper. Further, from the ADU unit, the transfer paper is attached to the ADU preresist roller (second roller) in order to correct the bending of the ADU circulating paper, and after a certain period of time, when a predetermined loop is generated, the ADU preresist roller is rotated and transferred. Paper is fed, or the drive of the ADU preregistration roller for loop generation is temporarily stopped, and when a predetermined condition is satisfied, the ADU preregistration roller is rotated to feed the transfer paper. Further, paper is fed from the manual feed tray by rotating the manual paper feed roller (third roller) for a predetermined time .

0010
[Problems to be Solved by the Invention]
An object of claims 1 to 3 is to reduce the number of motors by driving three rollers for correcting the bending of the transfer paper with the same motor, and to arrange a one-way clutch in the motor and each drive system. It is an object of the present invention to provide an image forming apparatus capable of realizing cost reduction and miniaturization, and an image forming apparatus having improved reliability by eliminating the need for an electromagnetic clutch having inferior reliability .

1 . In a switchback type or stack type automatic double-sided printing image forming apparatus, a loop roller (first roller) for applying the transfer paper from the paper feed tray to the registration roller for registration, and the transfer paper circulating the ADU. The ADU pre-registration roller (second roller) to which the transfer paper is applied to pre-register and the manual feed roller (third roller) for feeding paper from the manual feed tray are all driven by the same motor, and the motor is installed. A one-way clutch is applied to the motor and each drive system so that the first and second rollers are driven when rotated in the direction, and the third roller is driven when the motor is rotated in the direction opposite to the direction. An image forming apparatus characterized by being arranged.

2 . The operation timing of the motor is determined based on the point at which the front end or the rear end of the transfer paper passes through three photosensors arranged in the vicinity of the first roller, the second roller, and the third roller on the paper passage path. is, the image forming apparatus according to item 1, characterized in that controlling the rotation and drive.

3 . The motor is an image forming apparatus according to the item 1 or 2 wherein, characterized in that a stepping motor.

[0041]
【Effect of the invention】
It was possible to provide an image forming apparatus with improved reliability by driving three rollers for transporting transfer paper with the same motor, reducing costs and reducing the size, and eliminating the need for an electromagnetic clutch.

Claims (3)

In a switchback type or stack type automatic duplex printing image forming apparatus, a loop roller (first roller) for applying a transfer sheet from a paper feed tray to a registration roller for registration, and a transfer sheet circulating through an ADU The ADU pre-registration roller (second roller) for applying transfer paper to pre-register the paper and the manual feed roller (third roller) for feeding paper from the manual tray are all driven by the same motor, and there is a motor. When rotating in the direction, the first and second rollers are driven, and when rotating the motor in the opposite direction, the third roller is driven. An image forming apparatus that is arranged . The operation timing of the motor is determined based on the point at which the leading edge or trailing edge of the transfer paper passes through three photosensors arranged in the vicinity of each of the first roller, the second roller, and the third roller on the sheet passing path. The image forming apparatus according to claim 1 , wherein rotation control and driving are performed . The image forming apparatus according to claim 1 , wherein the motor is a stepping motor .