JPS58100056A - Curl removing apparatus for sheet material - Google Patents

Abstract

PURPOSE:To adjust the correction of a curl in a copier by providing two curl applying means comprising an endless belt having elasticity extended between rollers, which are disposed in such a manner as to eat into each other. CONSTITUTION:A sheet material 14 passed through a fixing device 12 is unevenly curled due to heat of a heat roll. Such a sheet material 14 is first clamped and transported between endless belts 17 and 17' of the first and second curl applying means 18, 19, whereby the seet material is curled clockwise and then curled counter-clockwise, and is discharged with high levelness. A sheet material curl removing apparatus 13 includes a driven roller 16 and a driving roller 15' which are combined in such a manner as to reciprocally press each central portion of the endless belts 17', 17, whereby the correction of a curl can be changed by changing such pressure force.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sheet material decurling device for mechanically straightening and removing curls from sheet materials such as paper, films, metal plates, etc.

Generally, when sheet materials are left in a roll state for a long time,
When placed in a high humidity condition, curling occurs, such as when passing through the heat fixing device of a copying machine (or when exposed to heat).When curling occurs like this, it is difficult to transport due to its poor flatness. In other words, problems such as sheet jamming will occur, and the sheet material itself will also be disposed of as a defective product.Therefore, conventional methods have been used to remove curls from the sheet material and improve the flatness of the sheet material. Various devices have been proposed to improve this.

For example, the apparatus shown in FIG. 1 is one example. In the figure,
An endless belt 8 is stretched between the rotating shaft 1 and the driven shaft 2, and a swinger 4 that can move up and down is provided at the center of the upper surface of the endless belt 8. When the idler 4 is moved up and down to adjust the suppressing action on the endless belt 8, the rotary shaft 1 and the driven shaft 2 are configured to move left and right (in the direction of the arrow in the figure).

In this conventional example, when the sheet material is passed between the endless belt and the roller to correct the curl, the direction of the curl is known in advance, and the surface of the sheet material is adjusted so as to curl in the opposite direction. The drawback is that you have to look carefully at what's behind the scenes. Furthermore, a mechanism for moving the rotary shaft and the driven shaft in the left-right direction is required, making the device complicated.

On the other hand, a curl removing means is provided in which two frame cutting rollers are inserted into each other so that the curl direction is reversed between the first stage and the second stage, and a rigid cylindrical load is arranged in contact with the rollers. It is also known that two sets are provided. In this conventional example, there are two curling locations, and since the curling occurs in opposite directions, the sheet material being passed through can be easily straightened even if it is curled outwardly or outwardly. However, in this conventional example, since the leading edge of the sheet material is configured to abut against one of the frame cutting rollers, there is a drawback that if the sheet material is thin, the leading edge may be folded. Further, the amount of curl correction is determined by the diameter of the cylindrical load and the positional relationship between the two frame-cutting rollers, and is constant within one device, so there is a drawback that the amount of curl correction cannot be changed.

The present invention has been made in view of these points, and allows curls to be removed without checking the curl direction.
Another object of the present invention is to provide a sheet material removing device that does not cause folding even when the sheet material is thin, and can arbitrarily set the amount of curl correction.

An embodiment of the present invention will be explained below in FIG.

FIG. 2 is a schematic diagram showing the internal configuration of a copying machine embodying the present invention. In the figure, 5 is a photoreceptor, 6 is a charger, ? 1 is a developing device, 8 is a transfer charger, 7 is a cleaning pusher, 10 is a registration roller, 11 is a separation belt, 12 is a heat roller constituting a fixing device,
Both have known configurations. A sheet material curl removal device 18 according to the present invention is provided behind the fixing device 12.

In such a copying machine, the sheet material 14 is conveyed toward the photoreceptor 5 by the registration rollers 10, and after the toner particles are transferred by the action of the transfer charger 8, the sheet material 14 is transported to the vicinity of the fixing device by the separation bell (11). It has become.

This sheet material 14 receives heat from a heat roller in the fixing device, and may warp or curl unevenly. In such a case, when transporting the paper towards the output tray (not shown) or towards the sorter or the intermediate storage section for double-sided copying, the trough t is used as described above.
Therefore, a sheet material curl removal device was provided near the fixing device. FIG. 8 is an enlarged side view of this sheet material curl removal device. In the figure, the sheet material curl removing device 18 is similar to the first curling means 18 which includes a driving roller 15 which is a rotating roller, a driven roller 16, and a plurality of rubber endless bells (17) stretched between them. It is configured in combination with a second curling means 19 consisting of the configuration (the reference numeral has a dash). The sheet material 14 that has passed through the curling device 12 is first curled by a first curling means 18, as shown by the arrow in the figure. and second curling means 1
Endrespel (No. 9) 17' and is conveyed while being held between them and curled in a clockwise direction. Next, the second curling means 19 similarly curls the paper in a counterclockwise direction and discharges the paper, resulting in improved flatness. The driven roller 16 of the first curling means 18 and the driving roller 15' of the second curling means are mutually different endless rollers) 17', l? The combination is such that the central part of the body is pressed. Since the endless belts 17 and 17' are made of rubber as described above, they are stretchable and therefore the driven rollers 16. The amount of curl correction can be changed by the pressing force of the drive roller 15'. The amount of curl of the sheet material depends on the type of sheet material used,
It varies depending on the conveyance speed, amount of toner attached, fixing conditions, etc.

FIG. 4 is a sectional view taken along the line A in FIG. 8. Endrespel (as shown in the figure)17. l? ' are arranged alternately so as not to interfere with each other. However, even if these are arranged so as to overlap as shown in FIG. 5, there is no disadvantage to the percentage. First curling means 18. In the second curling means 19, the driving rollers 15. Driven roller 1
These first curling means 18.6' are the axis. If the second curl applying means 19 is made rotatable, the amount of biting into each endless belt can be adjusted, and therefore the amount of curl correction can also be adjusted.

Note that the sheet material curl removal device of the present invention can be placed anywhere on the sheet material conveyance path.

The present invention is constructed as described above, and has two curling means each having an elastic endless belt stretched between two rollers, and these curling means are arranged so as to be bitten into each other. , it is possible to achieve all the intended objectives.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a conventional example, and FIG. 2 is a schematic configuration diagram illustrating an embodiment of the present invention incorporated into a copying machine. 8 is an enlarged side view of a main part, FIG. 4 is a sectional view taken along the line A- in FIG. 8, and FIG. 5 is a sectional view showing another embodiment corresponding to FIG. 4. ■4...Sheet material, 15, 16, 15'
, 16'...Rotating roller, 17.17'...
...Endrespel), 18.19...1st. Second curling means. Agent Patent Attorney Kenjibu Take'``E1r・1'' (2ro 73 Figure 7 Otsuzo 251'Efl

Claims (1)

[Claims] A first curling means for curling the sheet material being conveyed in a certain direction, and then a second curling means for curling the sheet material in a direction opposite to the first curling means,
This first. Each of the second curling means includes two rotating rollers and a plurality of stretchable endless belts stretched between the rotating rollers, and one of the first and second curling means A sheet characterized in that the rollers are configured to press each other against the center portions of endless belts of other curling means, and the sheet material is decurled by conveying the sheet material between the endless belts. Material decurling device.