JP2981001B2 - Paper feeder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feeder for an image forming apparatus, and more particularly to a lower paper feeder suitable for an automatic double-sided paper feeder.

[0002]

2. Description of the Related Art In an automatic double-sided paper feeder, single-sided copied paper discharged onto an intermediate tray is pushed out by a conveying roller toward a pair of separation rollers serving as re-feeding means, and the paper is stacked. There is a known type in which a separation roller pair separates one sheet at a time from the lowest sheet one by one and refeeds the sheets.

In such a paper feeder, as described above, the paper is separated and separated by the separation nip of the pair of separation rollers, and the paper is re-fed one by one. In order to ensure the reliability, it has been proposed to provide a sheet handling assist mechanism upstream of the separation roller pair. For example, Japanese Patent Application Laid-Open No. 2-178134 proposes a technique in which a sheet bundle is abutted against a separating plate and fed while being shifted in a wedge shape.

[0004]

However, in the above prior art, when the number of sheets in a bundle is increased or when a sheet having a large coefficient of friction is handled, a large separating force is required to realize a desired displacement. And the load increases. Also,
If only the lower part of the sheet bundle shifts and the upper part does not shift at all, and is fed to the separation roller pair without any shift,
There is a problem in that the sheet bundle is closed before the nip, causing non-feeding, slipping, and multi-feeding of many sheets.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an abutting paper
Even if the paper has curls or if the paper buckles,
The upper guide plate parallel to the stacking surface of the
It is regulated and firmly butted against the stopper gate means,
The wedge shape can be easily adjusted, and the effect of paper quality is reduced.
And the support shaft is located above the upper guide plate.
And the rotation range of the stopper gate means is small.
It is an object of the present invention to provide a sheet feeding device which is made and is advantageous in design .

[0006]

SUMMARY OF THE INVENTION The above object, an intermediate tray for stacking accommodate paper after one-sided image formation, the intermediate tray
An upper guide plate provided in parallel to the sheet stacking surface of Lee, the arranged delivery side of the intermediate tray, the paper refeed means for retransmitting one by one from the lowermost sheet of the stacked sheet, said sheet refeeding means disposed separated Nitsupu upstream, and released paper edge and abutment, and the angle between the stacking surface of the intermediate tray sheet and its abutment surface at an acute angle, Ru is tilted the abutment surface on the upstream side With
And a transport roller for transporting the sheet discharged to the intermediate tray to the stop gate means on the re-transmission side.

[0007]

[Function] An upper guide plate is provided in parallel with the loading surface of the intermediate tray.
And the support shaft of the stop gate means is above the upper guide plate.
Position and rotate the
Paper is curled or buckled by any chance
Also, with the upper guide plate parallel to the loading surface of the intermediate tray,
The paper is regulated and securely abuts against the stopper gate means.
Therefore, it is possible to easily form a wedge shape . The abutment surface is opened by a solenoid or the like when the sheet bundle is fed again. Further, when the angle between the abutment surface and the stacking surface of the intermediate tray is 30 to 70 degrees, the reliability of re-feeding by the re-feeding means increases.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a copying machine centering on a sheet feeding device (double-sided sheet feeding device) according to an embodiment of the present invention. The sheet 2 on which single-sided copying has been performed is sent into the double-sided apparatus 100 via the fixing device 3, the branch claw 4, and the switch reversing device 5. The sheet 2 carried into the double-sided apparatus 100 is discharged from the discharge gates A1 to A4, which are predetermined according to the sheet length in the transport direction, onto the intermediate tray 101 and stored therein (long letters are short from A1 side). The letter is emitted from the A4 side). The discharged paper 2 slides on the already stored paper, is further transported by the transport roller 102, and abuts against the abutment surface 103a of the stopper 103 to align the leading edge of the paper.
When a predetermined number of sheets are stored, the stopper 103 is rotated about the support shaft 104 by the solenoid 106, and the conveyance path is opened. Thereafter, the half-moon-shaped feed roller 120 makes one rotation, and transfers the entire sheet bundle to the downstream separation roller pair 105. Then, the lowermost sheet is separated from the sheet bundle by the separation roller pair 105 and is sent out from the duplex apparatus 100. Reference numeral 1 denotes a photosensitive drum.

FIG. 2 is a configuration diagram showing a main part of the sheet feeding device. The stopper 103 is disposed upstream of the separation nip formed by the feed roller 105a and the separation roller 105b that form the separation roller pair 105, and the abutment surface 103a is moved back and forth from the conveyance path by the solenoid 106 as described above. The abutment surface 103a is located at the intermediate tray 1
01 is provided to be inclined toward the upstream side with respect to the loading surface. The abutment surface 103a of the stopper 103 rotates within the range indicated by a, but the angle θ between the horizontal position indicated by the broken line and the solid line position at which the sheet bundle abuts is desirably 30 to 70 degrees. The angle θ is also the angle between the sheet stacking surface of the intermediate tray 101 and the abutment surface 103.

The transport roller 102 is made of a material having a relatively low coefficient of friction, and is supported by a support arm 107. The support arm 107 is suspended from the rotation shaft 108.
A belt 109 is stretched between the rotation shaft 108 and the transport roller 102 to rotate the transport roller 102 in a counterclockwise direction. The sheet discharged to the intermediate tray 101 is transported by the transport roller 1
02 is conveyed to the abutment surface 103a of the stopper 103. After the paper abutment, the transport roller 102 slips on the paper, so that the abutted paper does not buckle. Further, as the number of sheets to be accommodated increases, the transport roller 102 can move upward about the shaft 108. In addition, 110 is an upper guide plate, 11
1 is a lower guide plate. As shown in FIG.
The support shaft 104 of the stopper 103 is located above the guide plate 110.
Is located.

According to the above-described configuration, the leading end of the sheet bundle after the accommodation can be stacked and accommodated in a substantially wedge shape in which the lower part precedes and the upper part gradually retreats as shown in FIG. Note that the shape of the paper at the leading end may be like the shape shown in FIGS. Also, as shown in FIGS. 6 to 8, immediately after refeeding, the lowermost sheet of the sheet bundle easily reaches the nip portion, and the upper part of the sheet bundle is separated from the separating means such as the separating roller 105b. (S ₁ > S _{0 in} the example of FIG. 6). However, S ₁ ; the amount of deviation of the sheet bundle up and down S ₀ ; the equation r in FIG. 8B; the separation roller radius t; the sheet bundle thickness In this way, the separate roller 105 shown in FIG.
The reaction force R from b is lost, and the forward force of the sheet bundle (F-R)
And troubles such as non-feeding and slipping can be remarkably reduced.

FIG. 3 is a schematic diagram showing a main part of a sheet feeding apparatus according to another embodiment. In this embodiment, an upper guide plate 110 is provided with a stopper function and has a similar inclination as described above. The surface 110a is formed. At the time of re-feeding, the intermediate tray 101 moves downward, and the sheet bundle is sent out by the sending roller 120 which is waiting below. FIG.
FIG. 9 is a diagram showing an example in which a friction pad 105c is provided instead of the separate roller 105b.

[0013]

As described above, according to the present invention,
An upper guide plate is provided parallel to the loading surface of the intermediate tray,
The spindle of the stop gate means is located above the upper guide plate
The paper has been rotated so that it
Even if there is curl or the paper buckles,
Paper is regulated by the upper guide plate parallel to the loading surface of the ray
The stopper gate means,
The wedge shape can be easily adjusted, and the effect of paper quality is reduced.
Can be eliminated. Also, the spindle is above the upper guide plate.
Position, so that the rotation range of the stopper gate means
Can be reduced, which is advantageous in design.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a copying machine centering on a sheet feeding device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a main part of the paper feeding device.

FIG. 3 is a configuration diagram of a main part of a sheet feeding device according to another embodiment.

FIG. 4 is an explanatory diagram showing the shape of the leading end of a wedge-shaped sheet bundle.

FIG. 5 is an explanatory diagram illustrating a shape of a leading end of a wedge-shaped sheet bundle.

FIG. 6 is an explanatory diagram illustrating a relationship between a separation roller pair and a leading end of a sheet bundle.

FIG. 7 is an explanatory diagram showing a relationship between a separation roller pair and a leading end of a sheet bundle.

FIG. 8 is an explanatory diagram showing a relationship between a separation roller pair and a leading end of a sheet bundle.

FIG. 9 is a configuration diagram showing another example of the separating means.

[Explanation of symbols]

Reference Signs List 101 Intermediate tray 102 Transport rollers 103, 110 Stopper (stopper gate means) 103a, 110a Abutment surface 105 Separation roller pair (refeeding means) 120 Delivery roller

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B65H 1/00-3/68 B65H 83/02

Claims (3)

(57) [Claims] 1. An intermediate tray for stacking and storing sheets on which a single-sided image has been formed, and an upper guide provided in parallel with a sheet mounting surface of the intermediate tray.
A plate, the disposed on the delivery side of the intermediate tray, the paper refeed means for retransmitting one by one from the lowermost sheet of the stacked paper, the disposed Nitsupu upstream of the separation sheet refeeding means, and released paper leading abut, and the angle between the abutment surface and the intermediate tray stacking surface of the sheet at an acute angle, Rutotomoni tilted the abutment surface on the upstream side, the supporting shaft of the upper guide plate
And Sutotsupageto means is positioned above, sheet feed device being characterized in that a conveying roller for conveying to the said Sutotsupageto means retransmission side released sheet to the intermediate tray. 2. The sheet feeding device according to claim 1, wherein the stop gate means is provided such that an abutting surface thereof can be opened upward. 3. The sheet feeding device according to claim 1, wherein an angle between a loading surface of the intermediate tray and an abutment surface of the stop gate means is 30 to 70 degrees.