A sheet supply apparatus includes a sheet supporting device for supporting sheets, a sheet supply for positively contacting the sheet supported by the sheet supporting device and for feeding out the sheet, a release mechanism for releasing contact between the sheet supply and the sheet, a separation device for separating the sheets fed by the sheet supply one by one, a pair of convey rotary devices for conveying the separated sheet, and a controller. The controller effects control such that, after the sheet separated by the separation device is conveyed by a predetermined amount by the convey rotary devices, in a condition that the contact between the sheet supply and the sheet is released by the release mechanism, the sheet is conveyed in a reverse direction by the convey rotary devices until a tip end of the sheet leaves a nip of the convey rotary devices, and then the sheet is sent toward the nip of the convey rotary devices by the sheet supply to urge the tip end of the sheet against the nip of the convey rotary devices, which are now rotated in a reverse direction.
The present invention relates to a device for switching a pickup roller of an inkjet printer to eliminate an unnecessary load due to maintenance of a contact state between the pickup roller and a knockup plate. The device maintains the contact state between the pickup roller and the knockup plate during a paper feed operation by mounting a rotatable cam device on the paper feeder part. The cam separates the pickup roller from the knockup plate according to the rotational direction of the line feed motor 24 as the driving system of the paper feeder part. After the feed operation has ended, the cam separates the pickup roller from the knockup plate and, as a result, an unnecessary load after the paper feed has ended is eliminated. A uniform quality for the line feed can be gained by feeding the paper without an excessive load at the beginning, and accordingly loss of printing quality (white line, etc.) is prevented.
An improved image forming apparatus is provided for performing a printing operation on a series of paper and having a serial paper feeding device and a single sheet feeding device. The apparatus causes no paper jams of the series of paper while returning the series of paper to switch from a serial paper feeding mode to a single sheet feeding mode. The image forming apparatus includes a tractor wheel for conveying a series of paper to a printing area and for retreating the series of paper, and a tractor shaft for pivoting the tractor wheel. The image forming apparatus for feeding the series of paper by a serial paper feeding device causes a certain backlash in an initial pivotal movement of the tractor wheel and the tractor shaft. The image forming apparatus for preventing a paper jam during a retreating of the series of paper further includes an eject roller for feeding or retreating the paper which is conveyed by the serial paper feeding device by a forward and backward rotation thereof; an eject shaft for providing rotational force to the eject roller; an eject gear for causing a backlash at the eject shaft and the eject roller in the initial pivotal movement thereof, the eject gear for providing the rotational force to the eject shaft; a backlash hole formed in a certain location of the eject gear to race for causing the backlash at the eject gear in an initial pivotal movement; and a shaft pin fixed on the eject shaft after being passed through the backlash hole, for transmitting the rotational force of the eject gear to the eject shaft, thereby driving the eject shaft.
A paper jamming prevention device includes a conveying portion for conveying a sheet of paper from a paper feeding portion according to a feed command; a discharging portion for receiving the conveyed sheet of paper for discharge; and a base frame, installed between the conveying portion and the discharging portion, having a flat surface disposed toward the conveying portion and a curved conveyance surface disposed toward the discharging portion, the conveyance surface deviating from the flat surface toward the discharging portion. The conveyance surface has a curved middle region and side regions which slope symmetrically upward on each side of the base frame. The discharging portion is made up of discharging rollers and star wheels installed along the curvature of the conveyance surface.
A recording apparatus includes a recording section, a convey section, and a discharge section. The invention further includes an urging device for urging a pinch roller against a recording sheet, an urging force controller for controlling an urging force of the urging device, and a detector for detecting that a trail end of the recording sheet is conveyed to a predetermined position disposed upstream of a position where the trail end of the recording sheet leaves the pinch roller. The urging force controller reduces or releases the urging force of the urging device on the basis of a detection result from the detector, thereby eliminating the force of the pinch roller acting on the trail end of the recording sheet. The apparatus prevents the conveying accuracy of the recording sheet from being adversely affected.
The present invention relates to a sheet material conveying apparatus comprising first conveying means for conveying a sheet, material second conveying means for conveying, on a downstream side in a sheet material conveyance direction of the first conveying means, the sheet material and a plurality of guide members for forming a curving conveyance route located between the first conveying means and the second conveying means. The guide member forms the curving conveyance route located on an inner side among the guide members is a rotary body rotatably, which is arranged with no pressing member for pressing the sheet material to the rotary body.
