JPH09110290A - Paper sheet bundle turning-in device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce rotational torque of rollers by arranging a thin bundle turning-in nip roller device composed of a pair of rollers brought into pressure contact with each other with weak force and a thick bundle turning-in nip roller composed of a pair of rollers energized with stronger force. SOLUTION: When the number of sheets of a paper sheet bundle is a few, a fold line is applied by a pre-nip roller device 2, and the paper sheet bundle is completely turned in by a first nip roller device 5. When the number of sheets of the paper sheet bundle is many, a fold line is applied by the pre-nip roller device 2 and a first nip roller device 5, and the paper sheet bundle is completely turned in by a second nip roller 7. The second nip roller 7 can reliably turn in a thick bundle since it is energized by a strong third spring member 8. Since a gap S is formed between respective rollers of the second nip roller 7, deforming resistance of a rubber elastic body on a roller surface is eliminated, so that rotational torque of the rollers can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet bundle folding device mounted on a post-processing device of a printing machine or a copying machine.

[0002]

2. Description of the Related Art Generally, a sheet bundle is folded by pushing the center of the side surface of the sheet bundle to be folded by the tip of a knife edge plate to bend the central portion of the sheet bundle and pushing it into the nip portion of a pair of sheet folding rollers pressed against each other. In this case, the sheet bundle is passed through the nip portion of the roller pair.

In a conventional simple type sheet bundle folding device, the roll pair is pressed against each other by a pressing spring, and the roll pressure is determined by the strength of the spring.
Therefore, in order to fold a thick sheet bundle, the spring force of the pressing spring must be increased. However, when the spring force is increased, there is a problem that the rotation torque is increased due to the deformation of the rubber on the roll surface.

As a solution to such a problem, as described in JP-A-3-13455 and JP-A-4-164780, a small gap is provided between a pair of sheet folding rollers and folding is performed. It has been proposed to change the gap according to the number of sheets. However, in this case, there is a problem that a mechanism for changing the gap according to the number of sheets to be folded is required. Also, 1
There is a problem in that it is necessary to set a minute gap so that even a single sheet can be folded surely, which requires labor for adjustment and high mechanical accuracy.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to reliably fold a sheet bundle regardless of the number of sheets. Another object of the present invention is to reduce the rotation torque of the roll. Another object of the present invention is to stably fold a bundle of sheets without increasing the accuracy of the gap between rolls.

[0006]

FIG. 1 is an explanatory view showing the principle configuration of a sheet bundle folding apparatus of the present invention. The sheet bundle folding device of the present invention includes a pre-nip roll device 2 for taking in the sheets 1 to be folded, a first spring member 3 for pressing the rolls of the pre-nip roll device 2 against each other, and a pre-nip roll for the central portion of the sheets 1 to be folded. A plate-shaped member 4 such as a knife edge plate to be pushed into the nip portion of the device 2, a first nip roll device 5 arranged on the downstream side of the pre-nip roll device 2, and a first nip roll device 5
Second spring member 6 for pressing the respective rolls of the sheet into pressure contact with each other
And a second nip roll device 7 arranged downstream of the first nip roll device 5 and having a gap S at a predetermined interval between the rolls, and each roll of the second nip roll device 7 in the direction of approaching each other. The second spring member 6 is provided with a third spring member 8 that is biased by a stronger force.

When the number of sheet bundles is small, the pre-nip roll device 2 makes a crease, and the first nip roll device 5 completely folds the sheet bundle. The pressure contact force in the first nip roll device 5 is weaker than the pressure contact force in the subsequent second nip roll device 7, but since the number of sheet bundles is small, the sheet bundle is surely folded. The sheet bundle folded by the first nip roll device 5 passes through the gap S between the second nip roll devices 7 as it is and is conveyed.

When the number of sheets is large, the pre-nip roll device 2 and the first nip roll device 5 make a crease, and the second nip roll 7 completely folds the sheet bundle. Since the second nip roll 7 is biased by the strong third spring member 6, the thick bundle can be surely folded. Further, since the gap S is formed between the rolls of the second nip roll 7, the deformation resistance of the elastic body of the rubber on the roll surface is eliminated when the sheet bundle does not enter between the rolls. , The rotation torque of the roll is small.

[0009]

FIG. 2 is a schematic perspective view showing an embodiment of the sheet bundle folding apparatus of the present invention. FIG. 3 is similar to FIG.
It is explanatory drawing which shows operation | movement of the sheet bundle folding apparatus shown in FIG. The members corresponding to those shown in FIG. 1 are designated by the same reference numerals.

The pre-nip roll device 2 is composed of a pair of rolls 2a and 2b having a diameter of 20 to 30 mm and having an elastic member such as rubber on at least the surface thereof and pressed against each other. Each of them has a length of about 5 to 10 mm, and a plurality of them are attached to the rotating shafts 9a and 9b at predetermined intervals in the axial direction, and the entire length is about 200 mm. Each roll 2a,
The pressing force of the first spring member 3 that presses the two 2b against each other is selected to have a strength such that a thin sheet bundle can be folded, for example, about 3 to 4 kg / 200 mm. An escape groove 4a is formed at a position of the plate member 4 corresponding to each roll 2a, 2b.

The first nip roll device 5 comprises a pair of rolls 5a and 5b which are in pressure contact with each other, and the rolls 5a and 5b are provided along the axial direction of the rotary shafts 10a and 10b. The first nip roll device 5 is composed of a pair of rolls 5a and 5b that are in pressure contact with each other, and the rolls 5a and 5b are provided along the axial direction of the rotary shafts 10a and 10b. The pressing force of the second spring member 6 that presses the rolls 5a and 5b into contact with each other can completely fold a thin sheet bundle, but is insufficient to completely fold a thick sheet bundle, such as a certain strength. , 5 to 6 kg / 200 mm.

The second nip roll device 7 is composed of a pair of rolls 7a and 7b which are in pressure contact with each other, and the rolls 7a and 7b are provided along the axial direction of the rotary shafts 11a and 11b. Collars 12a and 12b are provided at both ends of the rolls 7a and 7b in the axial direction. When the distance between the surface of the roll 7a and the surface of the roll 7b is S, the collars 12a and 12b are arranged so that the circumferences of the collars 12a and 12b protrude from the surface of the rolls 7a and 7 by S / 2.
Select dimensions. The distance S is, for example, about 1 mm. The pressing force for folding the paper in the second nip roll device 7 is set to about 8 to 10 kg / 200 mm.

Further, between the first nip roll device 5 and the second nip roll device 7, an upper chute plate 13a and a lower chute plate 13b provided with a sheet conveying path interposed therebetween.
A paper chute device 13 composed of is arranged.

FIG. 3 (a) shows the state of the sheet bundle folding device before folding the sheet bundle, and the sheet 1 to be folded is shown in FIG.
Is disposed between the plate-shaped member 4 and the pre-nip roll device 2 in a direction orthogonal to the sheet conveying direction of the sheet bundle folding device. Next, the plate member 4 moves in the direction of arrow A, and the central portion of the sheet 1 is pushed into the nip portion of the pre-nip roll device 2 by the plate member 4 as shown in FIG. The rotation of the roll of the pre-nip roll device 2 makes a crease in the central portion of the sheet 1, and the crease portion is conveyed to the nip portion of the first nip roll device 5.

When the number of sheet bundles is small, the pre-nip roll device 2 makes a crease, and the first nip roll device 5 completely folds the sheet bundle. The pressure contact force in the first nip roll device 5 is weaker than the pressure contact force in the subsequent second nip roll device 7, but since the number of sheet bundles is small, the sheet bundle is surely folded. The sheet bundle folded by the first nip roll device 5 passes through the gap S between the second nip roll devices 7 as it is and is conveyed.

When the number of sheets is large, the pre-nip roll device 2 and the first nip roll device 5 make a crease, and the second nip roll 7 completely folds the sheet bundle as shown in FIG. 3 (c). Be done. Since the second nip roll 7 is biased by the strong third spring member 6, the thick bundle can be surely folded. Also, the second
Since the gap S is formed between the rolls of the nip roll 7 of No. 1, the rotation resistance of the elastic body of the rubber on the roll surface is eliminated when the sheet bundle does not enter between the rolls. It requires less torque.

Further, since the nip roll device for the thin sheet bundle is arranged on the upstream side of the sheet conveying path and the nip roll device for the thick sheet bundle on the downstream side is arranged, when the number of sheet bundles is large, The folding operation can be performed to a certain extent by using the nip roll device for the sheet, and the folding operation by the nip roll device for the thick sheet bundle can be ensured.

Further, since the gap S of the nip roll device for the thick sheet bundle is not adjusted to fold the thin sheet bundle, the accuracy of the gap S of the roll device can be lowered.

[0019]

As described above, in the present invention,
Nip roll device for thin bundle folding consisting of a pair of rolls pressed against each other with a weak force, and thick bundle folding device consisting of a pair of rolls having a predetermined interval and biased with a stronger force than the nip roll device for folding thin bundle The nip roll device for use is arranged in series with respect to the paper transport path, so that the following effects are achieved.

(1) Regardless of the number of sheets, the sheet bundle can be surely folded.

(2) Since the amount of deformation of the roll is small, the rotational torque of the roll can be reduced.

(3) A small number of sheets can be folded without increasing the accuracy of the gap between the rolls.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a basic configuration of a sheet bundle folding device of the present invention.

FIG. 2 is a schematic perspective view showing an embodiment of the sheet bundle folding device of the present invention.

FIG. 3 is an explanatory diagram showing an operation of the sheet bundle folding device shown in FIG. 2.

[Explanation of symbols]

1 ... Paper, 2 ... Pre-nip roll device, 3 ... First spring member, 4 ... Plate member, 5 ... First nip roll device, 6 ... Second spring member, 7 ... Second nip roll device, 8 ... Third spring member

Claims (1)

[Claims] 1. A nip roll device for folding a thin bundle, which comprises a pair of rolls pressed against each other with a weak force, and a pair of rolls which are spaced apart from each other by a stronger force than the nip roll device for folding a thin bundle. A sheet bundle folding device comprising: a thick-bundle folding nip roll device, which is formed of, and is arranged in series with respect to a sheet conveying path.