JP2666484B2 - Paper feeding method in paper feeding device of image forming apparatus - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feeding method in an image forming apparatus such as an electronic copying machine or a printer.

[Conventional technology]

The paper feeder of the image forming apparatus includes a feed roll that feeds the paper stored in the cassette tray, a trans roll that transports the paper fed by the feed roll, and a paper roll that feeds the paper transported by the trans roll. A registration roll for feeding the sheet toward the transfer section after temporarily stopping the tip by abutting the tip against the nip section and feeding the sheet toward the transfer section. As disclosed in Japanese Patent Application Laid-Open No. 62-244846, a trans-roll is rotated so that the sheet does not bend between the resist roll and the trans-roll when the sheet is fed by the above-described resist roll. The paper is conveyed.

[Problems to be solved by the invention]

In the above-described conventional paper feeding method, since there is no alignment correction in the trans-roll section, it may not be possible to completely correct variations in skew and lead edge registration that occur during conveyance by the feed roll.

Further, since the transformer roll is rotating in the sheet feeding direction until the rotation of the registration roll starts, abnormal noise, abrasion of the relay roll, and sheet contamination occur at this time.

The present invention has been made in view of the above, and it is possible to satisfactorily correct the skew and the variation of the lead edge registration generated at the time of conveyance by the feed roll, and to generate the abnormal noise due to the trans roll at the time of registration. It is an object of the present invention to provide a paper feeding method in an image forming apparatus capable of preventing abrasion of a trans-roller and generation of paper stains.

[Means for solving the problem]

In order to achieve the above object, a paper feeding method in an image forming apparatus according to the present invention includes a feed roll that feeds the paper stored in a cassette tray, and a transformer that transports the paper fed by the feed roll. Feeding of an image forming apparatus including a roll and a registration roll for temporarily stopping the sheet of paper conveyed by the trans-roller against a nip portion and temporarily feeding the sheet to a transfer section. In the apparatus, the timing of the rotation of the transformer roll is controlled in a plurality of steps, and in the first step, the leading end of the sheet is caused to abut against the nip of the registration roll, and further fed in the next step. Then, the resist roll is rotated.

Further, in the sheet feeding device of the image forming apparatus, the timing of the rotation of the trans roll is controlled in a plurality of steps, and in the first step, the leading end of the sheet is abutted against the nip of the resist roll, and In the next step, the resist roll is rotated during the rotation of the transformer roll in the next step.

Further, in the paper feeding method in the paper feeding device of the image forming apparatus, the paper is fed so as to bend against the nip portion of the trans roll stopped by the feed roll.

(Operation)

By the rotation of the trans roll in the first step, the sheet is abutted against the nip portion of the registration roll to correct the skew and the lead edge registration during the feeding of the sheet, and the second step provides the ejection output of the sheet. .

In addition to the above-described operation, the paper is sent so as to bend and abut on the nip portion of the stopped trans-roll by the feed roll, so that the alignment of the paper is corrected at two locations of the trans-roll and the registration roll.

〔Example〕

 An embodiment of the present invention will be described with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a transfer unit, and 2 denotes a U-turn path type sheet feeding device in the transfer unit 1.

The transfer unit 1 includes a photosensitive drum 3, a developing roll 4, a transfer corotron 5, and the like.
, A feed roll 8 for feeding out the sheets 6 of the cassette tray 7 one by one, and a feed roll 1 provided at a predetermined distance upstream from the transfer corotron 5 of the transfer section 1 in the transport direction. It comprises a pair of resist rolls 9,9 and a pair of trans rolls 10,10 arranged in a U-turn section between the feed roll 8 and the resist rolls 9,9.

Each roll of the sheet feeding device in the above configuration operates according to the time chart shown in FIG.

That is, when a sheet feed start instruction is issued, first, the foot roll 8 is driven for a predetermined time to feed one sheet 6 on the cassette tray 7 to the trans rolls 10 and 10. Then, the trans-rolls 10, 10 rotate in the first step until the leading edge of the paper 6 comes into contact with the nip of the stopped registration rolls 9, 9 and the intermediate portion thereof is slightly curved upward. send. Then, after a short time, the second step is performed to feed the sheet 6 such that the middle portion of the sheet 6 is further curved. Then, at the same time as the rotation of the transformer rolls 10, 10 in the second step is stopped, the registration rolls 9, 9 are driven to rotate.

By the above operation, the leading end of the paper 6 sent out by the feed roll 8 is securely applied to the nip of the resist rolls 9, 9 by the rotation of the first steps of the trans rolls 10, 10, thereby correcting the skew of the paper. Is done. Further, the rotation of the transformer rolls 10, 10 in the second step causes a projection output in the feed direction of the paper 6 to be fed to the transfer unit 1 at an accurate angle and direction with respect to the registration rolls 9, 9.

FIG. 3 is a time chart showing an embodiment of claim (2) of the present invention.

In this embodiment, when the pre-start signal becomes NO, first, the feed roll 8 rotates and the paper 6 is sent out, and then the transformer rolls 10 and 10 rotate in the first step, and the leading end of the paper 6 Is fed to the nips of the resist rolls 9, 9 and the intermediate portion is slightly curved upward. Then, when the start signal is turned ON, the trans rolls 10 and 10 rotate in the second step, and the paper 6 is fed so that the middle portion of the paper 6 is further greatly curved. The registration rolls 9 rotate during the rotation of the transformer rolls 10 in the second step, and the paper 6 is fed to the transfer unit 1.

The above embodiment, as described above, trans roll 10,1
During the second step rotation of 0, the registration rolls 9, 9 rotate to feed the paper 6 to the transfer unit 1.

According to this embodiment, generation of abnormal noise, roll abrasion, paper contamination, and the like is prevented when the trans rolls 10, 10 continue to rotate until the registration rolls 9, 9 start rotating.

After the paper 6 reaches the registration rolls 9, 9, the transformer rolls 10, 10 are turned off until the rotation of the registration rolls 9, 9 starts.
In contrast to the case of F, variations in the lead edge resist and skew, and the occurrence of paper jams and the like due to the resist rolls 9, 9 not catching the paper 6 are prevented.

Further, in the embodiment based on the timing charts shown in FIGS. 2 and 3, the feeding operation of the paper 6 by the feed roll 8 is shown by a virtual line in FIG.
The paper 6 may be fed such that the leading end of the paper roll is abutted against the nips of the stopped trans rolls 10 and 10 and the intermediate portion thereof is curved, and then the trans rolls 10 and 10 may be rotated. .

As a result, the paper alignment is corrected at two locations of the trans rolls 10, 10 and the registration rolls 9, 9, and the skew and lead edge resist variations that occur at the time of paper feeding are satisfactorily corrected.

In each of the above embodiments, the trans rolls 10, 1
In a state where the drive of the drive roller 0 is OFF, the transformer rolls 10 and 10 can be freely rotated by an electromagnetic clutch or the like.
If it is still on 0,10, the trans rolls 10,10 will move with the paper fed by the registration rolls 9,9.

Further, the rotation of the transformer rolls 10, 10 is not limited to the first and second steps, and may be a step rotation of more steps.

〔The invention's effect〕

According to the present invention, it is possible to satisfactorily correct variations in skew and registration that occur during conveyance by the feed roll 8, and to generate abnormal noise due to the trans rolls 10, Abrasion and the occurrence of paper stains can be prevented.

[Brief description of the drawings]

FIG. 1 is a schematic structural explanatory view of a sheet feeding device in a transfer section, and FIGS. 2 and 3 are time charts showing different embodiments of the sheet feeding method of the present invention. 1 is a transfer unit, 2 is a paper feeder, 6 is paper, 7 is a cassette tray, 8 is a feed roll, 9 is a registration roll, and 10 is a trans roll.

Claims (3)

(57) [Claims] A feed roll for feeding the paper stored in the cassette tray, a trans roll for transporting the paper fed by the feed roll, and a nip portion for leading the paper transported by the trans roll. The timing of the rotation of the trans roll is controlled in a plurality of steps in a paper feeder of an image forming apparatus that includes In the first step, the leading end of the sheet is made to abut against the nip of the registration roll, and the paper is further fed in the next step, and then the registration roll is rotated. Paper feeding method in the paper feeding device of the forming apparatus. 2. A feed roll for feeding paper stored in a cassette tray, a trans roll for transporting the paper fed by the feed roll, and a nip portion for leading the paper transported by the trans roll. The timing of the rotation of the trans roll is controlled in a plurality of steps in a paper feeder of an image forming apparatus that includes Then, in the first step, the leading end of the sheet is caused to abut against the nip portion of the registration roll, and further fed in the next step, and the registration roll is rotated during the rotation of the transformer roll in the next step. A sheet feeding method in a sheet feeding device of an image forming apparatus, wherein the sheet feeding method is configured to rotate. 3. A paper feeder according to claim 1, wherein the paper is fed so as to be abutted against a nip portion of the trans roll stopped by a feed roll. Method.