JPS58100057A - Curl removing apparatus for sheet material - Google Patents

Abstract

PURPOSE:To set the correction of a curl arbitrarily in a copier by providing two curl applying means comprising endless belts having elasticity extended between two pairs of fixed rollers and pressure rollers. CONSTITUTION:A sheet material passed through a fixing device 12 is unevenly curled due to heat. Such a sheet material 14 is first clamped and transported between an endless belt 18 and a pressure roller 19, and curled clockwise by the first curl applying means 20. Next, the sheet material is curled counter-clockwise in the same manner by the second curl applying means 21, and discharged with high levelness. The sheet material curl removing apparatus 13 includes pressure rollers 19, 19' fixed to a lever 28 which is turned by an adjusting gear 25 to change the pressure force, whereby the correction of a curl can be changed by such pressure force.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sheet material decurling device that mechanically corrects and removes 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,
Curling occurs when the paper is placed in a high humidity state or when exposed to heat such as when passing through a heat fixing device of a copying machine. If such curling occurs, the poor flatness will cause problems during transportation, that is, sheet jams, and the sheet material itself may also be disposed of as a defective product. Therefore, various devices have been proposed for removing curls from sheet materials and improving the flatness of the sheet materials.

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 20, and a swinger 4 that can move up and down is provided at the center of the upper surface of 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 shown in the figure) when adjusting the suppressing effect on the endless roller 8 by moving the idler 4 up and down.

In this conventional example, when the sheet material is passed between the endless belt and the floater to correct the curl, the direction of the curl is known in advance, and the front and back sides of the sheet material are adjusted to curl in the opposite direction. There are drawbacks that must be carefully considered. 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 both 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 on either the front or back side. 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 rod and the positional relationship between the two piece-cut 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 described below.

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 an electrostatic charger, 7 is a developing device, 8 is a transfer charger, 9 is a cleaning brush, 10 is a registration roller, 11 is a separation belt, and 12 is a heat roller that constitutes a fixing device. and
Both are publicly known! IIt composition. A sheet material curl removing device 1B 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 photoconductor 5 by the registration rollers 1O, and after the toner moat is transferred by the action of the transfer charger 80, the sheet material 14 is sent to the fixing device by the separation bell (IIK). It's now 5.

This sheet material 14 receives heat from a heat roller in the fixing device, and may warp or curl unevenly. In such a case, troubles are likely to occur when the paper is transported toward the output tray (not shown), or when transported toward the sorter or the intermediate storage section for double-sided copying. A sheet material curl removal device was installed near the 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 includes a driving roller 15 which is a rotating roller, a crown roller 17 which is a rotating roller rotatably provided on the outer periphery of a shaft 16, and a plurality of rollers stretched between them. An endless belt 18 made of rubber and a pressing roller 19 provided to press the center of the endless belt.
It consists of a first curling means 20 consisting of a first curling means 20 and a second curling means 81 having the same structure (the figure has a dash) and which curls in the opposite direction.

The sheet material 1 that has passed through the fixing device 12 is first conveyed in a first curling means 20 while being sandwiched between an endless bell 18 and a pressure roller 19, and is curled in a clockwise direction. Ru. Next, the second curling means 21 similarly curls the paper in a counterclockwise direction and discharges the paper, resulting in improved flatness. The pressing rollers 19, 19' are swingable in the direction of pressing the endless bell (18, 18') by a mechanism to be described later. Since this endless belt 18, 18' is made of rubber as described above, it is expandable and retractable, and therefore the amount of curl correction can be changed by the pressing force of the pressing roller 19, 19'. The amount of curl of the sheet material varies depending on the type of sheet material used, conveyance speed, amount of toner adhering, fixing conditions, etc.Side 4 Figure 8 is a view of the apparatus viewed from the direction of the arrow in Figure 8. It is a diagram. In the figure, the drive roller 15 is configured to be driven by a drive gear 22 receiving a transmission force from the outside, and each crown roller 17, which has a belt deviation prevention function, is provided with an endless roller (18). Further, the suppression roller 19 (and 19') is pivotally supported by one end of a lever 2B, which will be described later. Although this lever 2B is not shown, it is assumed that it is provided at both ends of the suppression roller 19 (and 19').

FIG. 5 is a schematic diagram showing the relationship between the pressure roller and the lever. In the figure, this lever 28 is rotatable around the pin 24, and the adjustment gear 25 and lever 28
It is designed to rotate by meshing with a gear part z6 formed in . Therefore, as described above, by turning this adjustment gear 25, the suppression roller 19, 19' can be swung in a direction perpendicular to the flat surface of the endless belt 18, 18', so that it can penetrate deeply or come into shallow contact with it. be. The adjusting gear 25 can also be adjusted manually while checking the flatness of the sheet material. It goes without saying that the pressing rollers 19 and 19' may be pressed by a separate pressing member.

FIG. 6 shows another embodiment of the pressure roller swing mechanism, in which the pressure roller 19.1 is moved by pulling the rod 28 connected to the pin z7 provided on a part of the lever 2B.
9' can be swung. This rod 28 may be moved by engaging a screw by rotating the handle 290. FIG. 7 shows yet another embodiment, in which a wire 80 may be used to pull the lever 2B. In this case, since the endless belt has elasticity, if you want to reduce the amount of curl, all you have to do is loosen the wire.

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 an elastic endless belt is stretched between two fixed rollers, and two curling means, a first and a second, are provided for pressing with a suppression roller. It is possible to achieve all desired objectives. −

[Brief explanation of drawings]

FIG. 1 is a diagram illustrating a conventional example, and FIG. 2 is a schematic configuration diagram illustrating an embodiment of the present invention incorporated into a copying machine. Figure 8 is an enlarged side view of the main parts, Figure 4 is a plan view seen from direction A in Figure 8,
FIG. 5 is a simplified diagram showing one embodiment of the swinging mechanism of the pressure roller, FIG. 6 is a simplified diagram showing another embodiment similar to FIG. 5, and FIG.
This figure is a simplified diagram showing yet another embodiment similar to FIG. 5. 14... Sheet material, 15, l? , 15'
, 17'...Rotating roller, 18.18'...
...Endless belt, 19.19'...
Pressing rollers, 20, 21...first and second curling means. TIFjJ/74Figure 57'X 67'77I2]

Claims (1)

[Claims] a first curling means for curling the sheet material being conveyed in a certain direction; a second curling means for curling the sheet material in a direction opposite to the first curling means; The second curling means each includes two rotating rollers provided at fixed positions, a plurality of elastic endless belts stretched between the rotating rollers, and a substantially central portion of the two rotating rollers. It consists of a suppression roller that is swingably provided so that the contact pressure against the endless belt can be changed, and the sheet material is conveyed between the endless belt and the suppression roller to remove curls from the sheet material. A device for removing curls from sheet materials.