SE542358C2

SE542358C2 - Device for binding sheets comprising a mechanism controlling the movement of a heating element

Info

Publication number: SE542358C2
Application number: SE1751073A
Authority: SE
Inventors: Per Swartz
Original assignee: Plockmatic Int Ab
Priority date: 2017-09-05
Filing date: 2017-09-05
Publication date: 2020-04-14
Also published as: SE1751073A1; WO2019048447A1

Abstract

A device for binding sheets (1) comprises a feeding section (10) and a binding section (20), wherein the feeding section (10) is adapted during operation to feed sheets of papers (4) to the binding section (20). The binding section comprises a tray (22) for storing a stack of papers (4a), a stop element (24) defining a position for the stack of papers (4a), and a heating element (26) movable between an upper end position, wherein sheets of paper (4) are free to be transported to the stop element (24), and a lower position, wherein the heating element (26) exerts a pressure on a leading edge portion of the stack of papers (4a). A mechanism is provided for controlling the movement of the heating element (26) such that the highest pressure exerted by the heating elements is moved from one end to the other of a binding area of the heating mechanism.

Description

DEVICE FOR BINDING SHEETS COMPRISING A MECHANISM CONTROLLING THE MOVEMENT OF A HEATING ELEMENT Technical field

[0001] The present invention relates generally to a device for binding sheets and more particularly to a device for producing a bound document from a plurality of sheets of paper by binding each sheet of paper to a previous sheet of paper by means of an imaging material.

Background art

[0002] In conventional binders, the sheets of paper are bound by means of stapling, clamping, gluing and/or sewing in the stack of papers. All these methods are associated with some kind of drawback, such as providing a separate binding material or environmental hazards, increasing the cost and complexity of binding.

[0003] The patent publication US 2001/0042599 A1 discloses an apparatus for binding media, wherein imaging material, such as toner, is used for binding media sheets. Although the disclosed apparatus removes some of the prior art drawbacks, it is still not suitable for many high-performance applications, requiring high speed and accuracy.

Summary of invention

[0004] An object of the present invention is to provide a device for binding sheets which is suitable for high-performance applications, providing alignment of sheets of paper with high speed and accuracy.

[0005] According to the invention, there is provided device for binding sheets comprising a feeding section and a binding section, wherein the feeding section is adapted during operation to feed sheets of papers to the binding section, wherein the binding section comprises a tray for storing a stack of papers, a stop element defining a position for the stack of papers, and a heating element movable between an upper end position, wherein sheets of paper are free to be transported to the stop element, and a lower position, wherein the heating element exerts a pressure on a leading edge portion of the stack of papers, the device being characterized by a mechanism controlling the movement of the heating element comprising a rotating arm driven by an electric motor, an actuating element connected to the heating element, wherein two springs are connected between the end portion of the rotating arm and a respective connection point on the actuating element for exerting a force on the actuating element towards the tray at rotation of the rotating arm such that during an operation cycle of the rotating arm the highest pressure exerted by the heating element is moved from one end to the other of a binding area of the heating element.

[0006] In a preferred embodiment, the actuating element is tiltable about an axis provided above the centerline of the tray.

[0007] In a preferred embodiment, a retaining element is provided, preferably arranged parallel to the heating element, and which is movable between an upper and a lower end position and which follows the downward movement of the heating element.

[0008] In a preferred embodiment, the tray is provided with a support made of a flexible material, preferably silicone rubber, in the area of the heating element.

[0009] In a preferred embodiment, a hollow tube is provided around the spring.

Brief description of drawings

[0010] The invention is now described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a top view of a device according to the invention, Fig. 2 is a side view of the device of Fig. 1, Fig. 3 is a cross-sectional view of an alignment roller where one of the feeding wires is provided, Figs. 4a and 4b show a feeding wire in two different positions, explaining the reciprocating movement thereof, Figs. 5a-d are end views of the device of Fig. 1 showing an arrangement for operating the heating element of the device, and Fig. 6 shows an alternative embodiment of an arrangement for operating the heating element.

Description of embodiments

[0011] In the following, a detailed description of a device for binding sheet will now be given with reference to the drawings. It will be appreciated that when reference is made to different directions, such as “up” or “down”, this reference is made when the device is in normal operation, i.e., as shown in the figures.

[0012] Fig. 1 is a top view of a paper treatment device, particularly for binding sheets of paper, generally designated 1. The device comprises a frame 2 supporting the different parts of the device, which are divided into two main sections: a feeding section 10 and a binding section 20. The device is adapted to be operably connected to a printer (not shown), from which sheets of paper are fed to the feeding section 10, i.e., the printer is connected to the left end of the device as shown in Figs. 1 and 2. A sheet of paper 4 is shown being fed in the feeding section 10 in the direction indicated by an arrow. When leaving the feeding section, this sheet of paper 4 will be positioned on a tray 22, thereby forming part of a stack of papers 4a formed by a plurality of papers that has successively been transported by the feeding section 10.

[0013] The feeding section will now be described in detail, initially with reference to Figs. 1 and 2. It comprises a plurality of feeding wires or belts, in the shown embodiment five wires 12. These wires 12 are shaped as loops running around three rollers 14a-c, of which at least one is rotated by means of a motor, such as an electric motor (not shown). The rollers are two upper rollers 14a, 14c and a lower roller 14b. The direction of movement of the feeding wires 12 are shown by arrows in the figures. The roller 14c is a conventional rollers provided with grooves for keeping the wires in place during operation.

[0014] However, rollers 14a, 14b, i.e., the rollers closest to the binding section 20, are provided with a non-circular cross-sectional shape where the feeding wires 12 rest on the roller. In a preferred embodiment, see Fig. 3, the cross-sectional shape is square or essentially square, but it may take other shapes as well, such as hexagonal or elliptical. This results in a reciprocating movement of the feeding wires 12 in the direction of transportation of the sheets of papers, as shown in Figs. 4a and 4b. Fig 4a shows a first rotational position of the rollers 14a, 14b wherein the feeding wire 12 is in a leftmost position, since the groove in the rollers 14a, 14b is the deepest in the area facing the tray 22, due to the irregular depth resulting from the square cross-sectional shape. When the rollers 14a, 14b have rotated 45 degrees clockwise from the position shown in Fig. 4a, see Fig. 4b, the groove in the rollers 14a, 14b are the shallowest. The two adjustment rollers 14a, 14b are interconnected by a toothed belt 16 or the like to ensure that the rotate synchronously, i.e., that the depth of the grooves facing the tray 22 are essentially the same.

[0015] When a sheet of paper leaves the feeding section 10, the reciprocating movement of the feeding wires 12 will result in a “push” on the trailing edge of the sheet of paper being transported. This “push” will help aligning the sheet of paper 4 so that the stack of papers 4a will consist of properly aligned sheets of papers. This proper alignment makes subsequent cutting unnecessary, simplifying the binding process.

[0016] Although the feeding section 10 has been described as part of a device for binding sheets, it will be appreciated that the alignment function thereof can be applied in any kind of paper treatment device wherein feeding of sheets of papers is necessary, such as printers and booklet making machines.

[0017] The binding section will now be described in detail, initially with reference to Figs. 1 and 2. This comprises a stop element 24 provided at the end of the tray 22 and being adapted to act as a stop for sheets of papers 4 being fed by the feeding section 10. The combination of this stop element and the reciprocating function of the feeding wires 12 results in a perfect alignment of the stack of sheets 4a.

[0018] Close to the stop element 24, i.e., in the area of the leading edge of the sheets of paper 4, an elongated heating element 26 is provided. This heating element 26, which also acts a press, is movable up and down as indicated by the arrow between an upper end position, wherein the sheets of paper 4 are free to be transported to the stop element, and a lower end position, wherein the heating element 26 exerts a pressure on the leading edge portion of the stack of papers 4a.

[0019] The sheets of papers 4 being fed to the binding section 20 have been provided with an imaging material, such as toner, along the leading edge of the sheet of paper, as described in the prior art document US 2001/0042599 A1 referred to in the background section. When the heating element 26 exerts a pressure on the stack of papers 4a in this area and simultaneously heats this area, the imaging material will create a bond between the uppermost sheet of paper and the next uppermost sheet of paper. In a preferred embodiment, the heating element 26 is heated to approximately 200° C. After a predetermined time, the heating element 26 reverts to its upper end position, allowing another sheet of paper 4 to be added to the top of the stack of papers 4a.

[0020] In order to ensure that the uppermost sheet of paper of the stack of papers 4a does not stick to the heating element 26, a retaining element 28 is preferably arranged parallel to the heating element 26. This retaining element is also movable between an upper and a lower end position and follows the downward movement of the heating element 26. However, when the heating element 26 starts its movement upward, the retaining element 28 temporarily remains resting on the stack of papers 4a to ensure that this remains firmly in place on the tray 22. This retaining element 28 may be slightly spring loaded, although it may be sufficient that the weight of the retaining element 28 keeps the uppermost sheet of paper in place.

[0021] In order to improve the pressing function, a support made of a slightly flexible material 22a, such as silicone rubber, may be provided on the tray 22 in the binding area, i.e., in the area of the heating element 26.

[0022] This bonding procedure is repeated for every new sheet of paper 4 added to the stack of papers 4a, resulting in a secure binding.

[0023] The mechanism controlling the movement of the heating element 26 will now be described with reference to Figs. 5a-d, showing an end view of the device. The mechanism comprises a rotating arm 30 driven by a suitable arrangement, such as an electric motor 32. Two springs 34a and 34b are connected to the end portion of the arm 30 a first end. At a second end of the springs 34a, 34b opposite the first end, the springs 34a, 34b are connected to a bar 36 at a respective connection point 36a, 36b. The bar 36 is an actuating element connected to the heating element 26. As seen in Fig. 5b, for example, the bar 36 is slightly tiltable about an axis provided above the centerline of the tray 22. It should be appreciated that the degree of tilting is exaggerated in the figures for ease of understanding of the function.

[0024] The operation of the mechanism shown in Figs. 5a-d is as follows. In an initial position, shown in Fig. 5a, the arm 30 is directed upward, i.e. towards a point between the two connection points 36a, 36b. This results in a spring force on the bar 36 that is comparatively small and evenly distributed between the two connection points 36a, 36b. In other words, the distance between the arm 30 is the same to the two connection points. This force is applied when the heating element 26 is in its upper end position.

[0025] Turning now to Fig. 5b, a position for the arm 30 is shown wherein it has been rotated 45 degrees clockwise from the initial position shown in Fig. 5a. This results in a greater distance from the arm 30 to the first connection point 36a and the downward force exerted by the first spring 34a is therefore greater than the downward force exerted by the second spring 34b. This force, which is higher than the force exerted in Fig. 5a and therefore moves the heating element 26 downward against the stack of papers 4a, is transferred to the heating element 26 which therefore exerts a higher pressure at one end of the elongated binding area.

[0026] The rotation of the arm 30 continues and Fig. 5c shows a position straight down, also resulting in an even downward force on the bar 36, although this force is higher than the force exerted in Fig. 5b.

[0027] Fig. 5d shows a position of the arm 30 directed to the left, resulting in a higher force on the right portion of the bar 36. Thus, during the operation cycle shown in Figs. 5a-d, the highest pressure exerted by the heating element 26 has been moved from one end to the other of the binding area. This ensures that the binding is performed evenly across the entire binding area. This function may be particularly relevant if the heating element 26, after long use, has an uneven or curved lower surface.

[0028] In order to avoid bending of the springs 34a, 34b, particularly during the last part of the revolution of the arm 30, a hollow tube 35a, 35b, indicated with dashed lines in Fig. 5a, may be provided around the springs.

[0029] In the emboent shown in Figs. 5a-d, two springs are provided. In an alternative embodiment, a single spring 34’ gives a similar function. The general design is the same, with an arm 30 and a bar 36 connected to the heating element 26, but instead of having two connection points on the bar, a single one 36a’ is provided. In order to increase the tilting function of the spring, this connection point may be provided as high as possible, and preferably on a pin 37 extending up from the bar 36.

[0030] Preferred embodiments of a device for binding sheets have been described. It will be appreciated that these may be varied without departing from the inventive idea as defined by the appended claims. Thus, additional springs may be provided in the operating mechanism for obtaining desired characteristics.

Claims

1. . A device for binding sheets (1) comprising a feeding section (10) and a binding section (20), wherein the feeding section (10) is adapted during operation to feed sheets of papers (4) to the binding section (20), wherein the binding section comprises a tray (22) for storing a stack of papers (4a), a stop element (24) defining a position for the stack of papers (4a), and a heating element (26) movable between an upper end position, wherein sheets of paper (4) are free to be transported to the stop element (24), and a lower position, wherein the heating element (26) exerts a pressure on a leading edge portion of the stack of papers (4a), characterzedy a mechanism controlling the movement of the heating element (26) comprising a rotating arm (30) driven by an electric motor, an actuating element (36) connected to the heating element (26), wherein two springs (34a, 34b) are connected between the end portion of the rotating arm (30) and a respective connection point (36a, 36b) on the actuating element (36) for exerting a force on the actuating element (36) towards the tray at rotation of the rotating arm (30) such that during an operation cycle of the rotating arm the highest pressure exerted by the heating element (26) is moved from one end to the other of a binding area of the heating element (26).

2. The device according to claim 1, wherein the actuating element (36) is tiltable about an axis provided above the centerline of the tray (22).

3. The device according to any one of claims 1 -2, comprising a retaining element (28), preferably arranged parallel to the heating element (26), and which is movable between an upper and a lower end position and which follows the downward movement of the heating element (26).

4. The device according to any one of claims 1 -3, wherein the tray (22) is provided with a support (22a) made of a flexible material, preferably silicone rubber, in the area of the heating element (26).

5. The device according to any one of claims 1 -4, comprising a hollow tube (35a, 35b) provided around the spring (34a, 34b).