KR20040074574A - Laminator draw control - Google Patents

Abstract

PURPOSE: A method for controlling the leading speed of a laminator is provided to efficiently inject a thermal adhesive to a material by controlling the rotational speed of a heated roller in a laminator. CONSTITUTION: An arm(18) pivots around a pivot pin(17) against a spring(24) when a material layer contacts a roller(11). Contact brushes attached to springs(19,20) move along tracks(22A,23B). The resistance of a sensor(10) changes when the springs contact the short track. The changed resistance is read and relayed to a motor. The motor influences on the processing speed. A feed roller leads a sheet at a speed proper for the thickness of the material. The heat applied by a heater softens the adhesive on the inward surface of an outer plastic layer. A supplementary heater applies heat to the sheet on the way to a discharge roller.

Description

Stacker Entry Speed Control {LAMINATOR DRAW CONTROL}

The present invention relates to laminators of the type used for laminating sheets, such as photographs, certificates or charts, for example between a pair of transparent plastic sheets, and more particularly, the thickness of the layer to be laminated. Although the present invention relates to a laminator having a mechanism for detecting and means for adjusting the processing speed of a sheet passing through a heating roller of the laminator according to the detected thickness, the present invention is not limited thereto.

Known laminators comprise a pair of internally heated rollers, which rollers are biased towards each other or at fixed intervals, and the layers to be laminated between them are pressed. Heat from the roller melts the adhesive surface on each plastic sheet, and the molten layer is injected to some extent into the sheet being laminated. Cards and thin papers are relatively simple to stack because the preset temperature and speed settings of the rollers achieve the required adhesion between the layers. However, when, for example, a thick sheet of cardboard is to be laminated, the preset temperature and speed settings can result in insufficient adhesive penetration into the cardboard and can also easily layer the finished product. For this reason, the finished finished product will have to go through the laminator up to two or perhaps three times. This can cause loss of productivity or even damage to the finished product.

It is an object of the present invention to overcome or ameliorate the above disadvantages and / or to more generally provide a thickness sensor for a laminate and a laminate incorporating the thickness sensor and the speed controlled lamination / heating roller.

In the present specification, in the thickness sensor for the layered sheet material coming into the lamination machine,

An arm moveable upon interaction with the laminated sheet material, and

Means for providing a variable resistor output according to the position of the arm

A thickness sensor comprising a has been described.

Advantageously, said means for providing a variable resistor comprises an electrical conductor mounted to said arm and providing a pair of exposed electrical contacts, and an exposed track contacted by each of said electrical contacts and at least one of said tracks. A PCB having a resistor for electrically connecting adjacent portions of the track.

Preferably, the tracks are each electrically isolated from one another and comprise end portions contacted by each of the electrical contacts to indicate that the stack is too thick.

Preferably, one of the ends includes a sub portion electrically contacted by one of the electrical contacts to provide an alarm signal that is electrically isolated from it and that the stack is of maximum allowable thickness.

Preferably, the arm is pivotably mounted on a pivot pin and the track is curved.

Preferably, the arm comprises at one end a roller that can contact the laminated sheet material, and the pivot pin is closer to the roller than the electrical contact.

Also, in a lamination machine,

A pair of heated rollers, and

The thickness sensor attached to the stacker in an upstream position of the roller and cooperating with the stacker to change the rotational speed of the roller

Including,

Between the pair of heated rollers the layers of sheet material are compressed for lamination

Laminators are further described.

Preferably, at least one of the rollers is driven by an electric motor, and the operating speed of the electric motor is changed by the thickness sensor.

Preferably, the stacker further comprises a pair of ejection rollers in a lower position of the heated roller.

Preferably, the discharge roller rotates in conjunction with the heated roller via a gear train between the discharge roller and the heated roller.

Preferred embodiments of the invention will now be described by way of example with reference to the accompanying drawings.

1 is a schematic perspective view of a thickness sensor for laminated sheet material.

2 is a schematic perspective view of the thickness sensor of FIG. 1 seen from another angle.

3 is a schematic side cross-sectional view of the laminate with the thickness sensor of FIGS. 1 and 2 attached.

4 is a schematic perspective view of a gear train to ensure that the roller and the roller rotate together.

1 and 2, the thickness sensor 10 is schematically illustrated. Sensor 10 includes a casing, in which a printed circuit board (PCB) 16 is mounted. An arm 18 is mounted on the pivot pin 17, and a coil spring 24 is wound around the pivot pin 17. The coil spring weakly deflects the arm in the direction shown in the figure. One end of the arm extends from the casing and supports the roller 11 to contact the downward surface of the stack of three sheets to be laminated. This is typically a bottom transparent plastic sheet, with a picture laminated as an example between the two plastic sheets.

An idler 12 is positioned above the roller 11, with each end of the idler 12 mounted by an idler support 13. Each idler support 13 projects downward telescopically from a spring casing 15 in which the coil spring 14 is located. Coil spring 14 holds idler 12 in a reference position, but permits upward movement of idler 12 if the overall height of the laminated sheet of material is too high. In that case, the stacker is shut down by the features described later.

Arm 18 has an electrically conductive bus 21 therein. There are two springs 19, 20 extending from the bus to the position between the arm 18 and the PCB 16. There may be an electric brush attached to the springs 19, 20 to engage the tracks 22, 23 formed on the PCB 16. Alternatively, the "spring" may be in direct contact with the track.

As shown in FIG. 1, the distance between the pivot pin 17 and the roller 11 is significantly smaller than the distance between the pivot pin 17 and the electrical contacts and the tracks 22, 23. This ensures that a small pivotal movement of the roller-side end of the arm 18 produces a large movement of the electrical contact, so that a relatively large scale PCB design can be adopted.

One of the tracks 22 is substantially continuous, but includes an electrical disconnect end 22A. The other track 23 is divided into a plurality of short segments electrically connected in series with the surface mount resistor 24. Along the track portion 22A, the track 23 includes electrical breaks 23A, 23B.

When the layer of sheet material contacts the roller 11, the arm 18 pivots about the pivot pin 17 against the spring 24. The contact brushes attached to the springs 19, 20 then move along the tracks 22, 23. When contacting adjacent portions of the short portion 23, the resistance of the sensor 10 changes. This provides an adjacent continuous variable resistor that can be used to control the speed at which the roller (described later) is driven.

When the arm 18 is aligned across the portions 22A, 23A, an alarm signal such as a "beep" sound is illuminated or the alarm light is illuminated indicating that the material being laminated is at or very close to the maximum allowable limit. . When the arm 18 is aligned across the track portions 22A, 23A, a shut-off condition occurs because jam is inevitable.

The thickness sensor 10 is attached to the stacker by mounting 25, where a mounting spring 26 that passes through an eye 34 extends from the mounting 25 to hold the sensor.

The laminator itself comprises a pair of heated feed rollers comprising an elastic rolling surface 26 surrounding the heater 28. At least one of these rollers will be driven by an electric motor (not shown). There is also a pair of downstream discharge rollers 30, at least one of which is rotated with the feed rollers 26. A pair of gear trains 32 achieves this, with one gear train 32 at each end of the roller. In order to rotate the rollers, an electric motor may be coupled to either of the gears of one or both gear trains 32, or may be directly coupled to the rollers.

An additional heater 29 is located between the feed roller and the discharge roller.

In use, the sheet to be laminated is provided at an upstream end of the stacker, which may be provided on a support tray 33. The sheet is fed into the stacker manually, with the lower sheet in contact with the roller 11. Next, the arm 18 makes a pivotal rotation that represents the thickness of the stack of sheets to induce adequate resistance to the sensor 10. This resistance is read and relayed to the motor to affect the processing speed of the material. The feed roller draws in the sheet at a rate appropriate for the material thickness and heat is applied by the heater 28 to soften the adhesive on the inward surface in the outer plastic layer. The molten adhesive is then at least partially injected into the intermediate layer. The supplemental heater 29 then applies additional heat to the sheet on the way to the exit roller 30 which rotates with the feed roller. The discharge roller also has an elastic surface to press the sheets together and provides the sheet to the collecting tray 31 for collection.

It should be understood that modifications and variations apparent to those skilled in the art should not be regarded as outside the scope of the present invention. By way of example, the arms may move linearly instead of pivoting and the rollers may be rotated together by means other than gear trains. Moreover, instead of and / or in addition to controlling the pulling rate, the resistance reading of the thickness sensor may be used to control the heat generated by the heater.

The laminating apparatus of the present invention can stack sheets such as photographs, certificates or charts between a pair of transparent plastic sheets, and more specifically, a mechanism for detecting the thickness of the layer to be laminated and the detected thickness. Accordingly, the processing speed of the sheet passing through the heating roller of the laminator can be adjusted.

In addition, according to the invention, the arms can move linearly instead of pivoting, and the rollers can be rotated together by means other than gear trains. Moreover, instead of and / or in addition to controlling the pulling rate, the resistance reading of the thickness sensor may be used to control the heat generated by the heater.

Claims (10)

A thickness sensor for a layered sheet material entering a lamination machine, An arm moveable upon interaction with the laminated sheet material, and Means for providing a variable resistor output according to the position of the arm Thickness sensor comprising a. The method of claim 1, The means for providing a variable resistor includes an electrical conductor mounted to the arm and providing a pair of exposed electrical contacts, and an adjacent portion of at least one of the track and the exposed track contacted by each of the electrical contacts. A thickness sensor comprising a PCB having a resistor for electrical connection. The method of claim 2, A thickness sensor comprising end portions each of which are electrically isolated from each other of the tracks and contacted by each of the electrical contacts to indicate that the stack is too thick. The method of claim 3, One of the ends comprises a sub portion electrically disconnected from itself and contacted by one of the electrical contacts to provide an alarm signal indicating that the stack is of maximum allowable thickness. The method of claim 2, The arm is pivotally mounted on a pivot pin and the track is curved thickness sensor. The method of claim 5, The arm includes a roller at one end thereof that can be in contact with the laminated sheet material, wherein the pivot pin is closer to the roller than the electrical contact. In a lamination machine, A pair of heated rollers, and The thickness sensor of claim 1 attached to the stacker at an upstream position of the roller and cooperating with the stacker to change the rotational speed of the roller. Including, Between the pair of heated rollers the layers of sheet material are compressed for lamination Stacker. The method of claim 7, wherein At least one of the rollers is driven by an electric motor, and the operating speed of the electric motor is changed by the thickness sensor. The method of claim 7, wherein And a pair of discharge rollers in the lower position of the heated rollers. The method of claim 9, And the discharge roller rotates in association with the heated roller via a gear train between the discharge roller and the heated roller.