GB2373759A

GB2373759A - Creasing machine

Info

Publication number: GB2373759A
Application number: GB0107811A
Authority: GB
Inventors: Wilfrid Macleod Garner; Paul Stuart Garratt
Original assignee: Morgana Systems Ltd
Current assignee: Morgana Systems Ltd
Priority date: 2001-03-29
Filing date: 2001-03-29
Publication date: 2002-10-02
Also published as: GB0107811D0

Abstract

The machine includes a creasing mechanism, a feed mechanism, a transport mechanism (8) e.g. rolls for transporting sheets of material through the creasing mechanism, and a control means for controlling operation of the creasing mechanism and the transport mechanism. The creasing mechanism includes an upper adjustably positioned creasing element (28) and a lower creasing element (26) that is moveable towards the upper creasing element to produce a crease in a sheet of material located between those elements, driven by a drive mechanism comprising a motor which, when a signal is given to perform a creasing step, is coupled to a shaft 48, which via a rod 50, causes a single vertical reciprocation of the element (26). An infra-red sensor 17 detects a sheet leading edge and, together with an encoder associated with upper roll (8) enable a microprocessor to monitor the exact position of the sheet passing through the creasing mechanism.

Description

CREASING MACHINE The present invention relates to a creasing machine and in particular, but not exclusively, to a creasing machine for use in the production and finishing of printed documents.

When producing a folded document, it is generally preferable first to form a crease in the document. This produces a neat fold-line and it reduces the risk of cracking or tearing when the document is folded.

Conventionally, documents have been creased on a platen press or using a hand-operated machine with a rotating scoring wheel, which rolls across the surface of the document to produce the crease. However, it has been found that this system can lead to cracking of the printed surface, particularly with documents printed using modem ink or toner-based digital printing systems, or on easily damaged materials.

Further, existing creasing machines are either very slow (in the case of hand-operated machines) and therefore unsuitable for anything but very small production runs, or require the manufacture of a custom creasing die (in the case of platen presses), and are suitable therefore only for very large production runs.

It is an object of the present to provide a creasing machine that mitigates at least some of the aforesaid problem.

According to the present invention there is provided a creasing machine including a creasing mechanism, a transport mechanism for transporting sheets of material through the creasing mechanism, and a control means for controlling operation of the creasing mechanism and the transport mechanism, said creasing mechanism including a pair of creasing elements, at least one of said elements being moveable towards the other element to produce a crease in a sheet located between the elements, and a drive mechanism for driving the moveable element.

The creasing machine can produce creases at predetermined locations and is capable of automatic operation. It can thus be used to crease a batch of documents relatively rapidly.

Further, it can be reprogrammed relatively easily to produce a different set of creases. It

is therefore highly adaptable. There is no necessity to mai. facture a new die for each creasing job and accordingly it is economical in use, even for short production runs.

Advantageously, the drive mechanism includes a drive motor and an eccentric drive member that is connected to said moveable element. The eccentric drive member may include a crankshaft that is connected to said moveable element through at least one linear actuator, for example a connecting rod. This is a simple and efficient drive system that is very effective and reliable in use.

Advantageously, the drive mechanism includes an incremental control device (for example a clutch assembly). The incremental control device may be controlled by said control means. Using an incremental control device allows the drive motor for the creasing mechanism to run continuously. There is no need therefore for the motor to accelerate up to speed, and this provides for fast operation. Further, because the running motor has considerable inertia, which assists operation of the creasing mechanism, the motor does not need to be as powerful as it would otherwise have to be.

Advantageously, the creasing machine includes a transport drive motor and a pair of input rollers for transporting sheets of material into said creasing mechanism. The creasing machine may include an encoder constructed and arranged to generate an output signal indicating the rotational position of at least one of said input rollers, and a sensor for sensing the leading edge of a sheet as it passes between the input rollers, said control means being connected to said encoder and said sensor to receive signals therefrom. This enables the control means to monitor the position of the sheet of material continuously as it passes through the creasing mechanism, which enables it to place the creases correctly.

The sensor is preferably an optical sensor, for example a infrared sensor.

The creasing machine may include a pair of output rollers for removing sheets of material from said creasing mechanism. The input and output rollers are preferably constructed and arranged to be driven synchronously, for example by means of a common drive belt.

The transport drive motor is preferably arranged to be controlled by said control means. Advantageously, the transport drive motor is a positional control motor, for example a stepper motor or a servo motor.

Advantageously, the control means is programmable, and is constructed and arranged to control the placing and number of creases produced by the machine according to predetermined requirements.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure I is an isometric view of the assembled machine; Figure 2 is an isometric view showing internal components of the creasing mechanism; Figure 3 is a sectional view from above, showing the paper transport mechanism; Figure 4 is an elevation showing the input side of the paper transport mechanism; Figure 5 is a left-hand sectional end view, showing components of the creasing mechanism; Figure 6 is a sectional front view showing components of the creasing mechanism: Figure 7 is a right-hand end view showing components of the creasing mechanism; Figure 8 is a partial sectional front view, showing components of the creasing mechanism; Figure 9 is a partial left-hand end view showing components of the creasing mechanism; Figure 10 is an isometric view at an enlarged scale, showing components of the creasing mechanism; and Figure 11 is a sectional left-hand view, showing parts of the paper transport and stacking mechanisms.

The document creasing machine, which is shown in Figure 1, includes a feed table 2, a housing 4 that contains the creasing mechanism, and a stacking tray 6. The feed table 2 is of a conventional kind, commonly used on printing and document finishing machines, and known as a"suction bottom feed system". This feed mechanism, which will not be described in detail, feeds sheets of paper or card one at a time from a stack into the paper transport mechanism of the creasing mechanism. The creasing mechanism is shown in detail in Figures 2 to 9. The mechanism 7 includes a pair of input rollers 8 and a pair of output rollers 10, arranged to transport a sheet of paper through the mechanism. Both pairs of rollers are driven by a stepper or servo motor 12 through a step-down gear 14 and a belt drive 16, which is arranged so that the rollers all rotate synchronously.

A through beam infrared sensor 17 is arranged just behind the nip of the input rollers to detect the leading edge of a sheet passing between those rollers. An encoder 18 is provided on one end of the upper input roller 8. The sensor 17 and the encoder 18 are connected to a microprocessor (not shown). By sensing the leading edge of the paper and the rotary position of the input roller, the microprocessor is able to monitor the exact position of the sheet of paper as it passes through the creasing mechanism.

The lower input roller is connected to a feed drive roller 20 under the feed table 2 by a second drive belt 22. This arrangement ensures that a sheet of paper is not fed into the mechanism while the input rollers are stationery.

The creasing mechanism, which is indicated generally by the reference number 24, is mounted between the two sets of rollers. This mechanism, which is shown in more detail in Figures 8,9 and 10, comprises an upper creasing component that is normally fixed (although its position is adjustable when the machine is not in use) and a lower creasing component that is mounted for vertical movement. In the arrangement shown in Figure 10, the upper creasing component comprises a blade 26 and the lower creasing component comprises an anvil 28. The positions of the blade and the anvil can however be swapped, so that the blade 28 is the fixed upper creasing component and the anvil 26 is the moving lower creasing component. Both creasing components comprise elongate metal bars having a substantially rectangular cross-section, the blade 26 having a profiled rib 30 on its lower edge and the anvil having a profiled recess 32 on its upper edge into which the rib fits. The profile of the rib and the recess can be changed, according to the desired form of the crease.

Each of the creasing components 26,28 includes at each of its ends a pair of pins 34a, 34b that engage a vertical slot 36 in the creaser unit frame 38. The inner pins 34b are eccentric and can be adjusted to adjust the lateral positions of the creasing components. The upper creasing component is locked in position by an adjusting mechanism 40 provided at each end of the component. This allows the vertical position and alignment of the component to be adjusted. The lower creasing component is can only be adjusted laterally, but can move vertically, the pins 34a, 34b being guided by the slot 36.

The lower component 28 is driven by a motor 42, for example an induction motor. The motor is connected through a drive belt 44 to an incremental control device 46 (for example a clutch) that is mounted on a crankshaft 48. Operation of the control device 46 is controlled electronically by the microprocessor. Two power links (or con rods) 50 are mounted on eccentric cranks 52 at the ends of the crankshaft and are connected at their upper ends to the lower creasing component 28. The motor 42 operates continuously but as the control device 46 is normally disengaged, it does not normally drive the crankshaft 48. When the control device 46 receives an"engage"signal from the microprocessor, it closes and the crankshaft is driven through one complete rotation. This drives the lower creasing component 28 upwards against the upper creasing component 26, thereby producing a crease in a sheet of card or paper located between those components, before returning it to its original bottom position. A microswitch 58, located beneath the lower creasing component 28, detects that it has returned to the bottom position and sends a signal to the microprocessor, which then disengages the clutch so that no further movement of the creasing component takes place until the next crease is to be formed.

The entire creasing mechanism can be tilted relative to the feed table, using a tilt lever 60.

This allows the angle of the crease to be adjusted, so that it is always perpendicular to the lay edge of the paper.

The stacking tray 6 is located downstream of the output rollers and comprises a sloping table having a back stop and two side guards, into which the creased documents are delivered by the output rollers.

Optionally, perforating or slitting wheels (not shown) may be mounted on the shafts of the output rollers, to form perforations or slits in the documents as they are fed between those rollers. A perforation stripper may also be provided.

The microprocessor may be programmed to produce a plurality of creases at predefined positions. Once the microprocessor has been programmed, operation of the machine is

fully automatic, the machine taking sheets from the feed table, creasing them as required and delivering the creased sheets to the stacker tray.

Operation of the creasing machine is as follows.

During set-up, the operator enters the positions of each of the creases in the microprocessor, using a keypad. The microprocessor can, for example, store the positions of up to nine creases in nine separate memory locations.

A sheet of paper or card is fed from the feed table into the nip between the input rollers 8, which then take over transport of the sheet from the feed system. Immediately the leading edge of the sheet exits from the input rollers it is sensed by the infrared sensor. The signal from the sensor is recorded by the microprocessor together with a rotary position signal from the encoder mounted on one of the input rollers. At this point, the sheet is considered to be registered and throughout its continuing journey through the machine its exact position is always known.

As the sheet approaches the position of the first crease, the stepper motor first slows down and then stops with the sheet in exactly the right place for that crease to be formed (to within an accuracy of, for example, 0.09mm or better). At this point the incremental control device is activated and the crankshaft is driven through one complete rotation, driving the lower creasing component 28 towards the upper creasing component 26 and trapping the sheet to form a crease. The lower creasing component then drops back to its original home position and the sheet is accelerated back up to full speed towards the next pre-set crease position. The same procedure is carried out for all subsequent creases. After the last crease has been formed, the sheet is ejected by the output rollers into the stacker for collection by the operator. This procedure is repeated for each of the remaining sheets, as they are fed one-by-one into the creasing mechanism from the feed table.

As the trail edge of the sheet exits from the nip of the input rollers, the sheet sensor detects the trail edge of the sheet and signals the microprocessor to feed another sheet from the stack of documents in the feed system.

Claims

CLAIMS 1. A creasing machine including a creasing mechanism, a transport mechanism for transporting sheets of material through the creasing mechanism, and a control means for controlling operation of the creasing mechanism and the transport mechanism, said creasing mechanism including a pair of creasing elements, at least one of said creasing elements being moveable towards the other creasing element to produce a crease in a sheet located between those elements, and a drive mechanism for driving the moveable creasing element.
2. A creasing machine according to claim 1, wherein said drive mechanism includes a drive motor and an eccentric drive member that is connected to said moveable element.
3. A creasing machine according to claim 2, wherein said eccentric drive member includes a crankshaft that is connected to said moveable element through at least one linear actuator.
4. A creasing machine according to any one of the preceding claims, wherein said drive mechanism includes an incremental control device.
5. A creasing machine according to claim 4, wherein said incremental control device is controlled by said control means.
6. A creasing machine according to any one of the preceding claims, including a transport drive motor and a pair of input rollers for transporting sheets of material through said creasing mechanism.
7. A creasing machine according to claim 6, including an encoder constructed and arranged to generate an output signal indicating the rotational position of at least one of said input rollers, and a sensor for sensing the leading edge of a sheet as it passes from between said input rollers, said control means being connected to said encoder and said sensor to receive signals therefrom.
8. A creasing machine according to claim 7, wherein said sensor is an optical sensor.
9. A creasing machine according to any one of claims 6 to 8, including a pair of output rollers for removing sheets of material from said creasing mechanism.
10. A creasing machine according to claim 9, wherein said input and output rollers are constructed and arranged to be driven synchronously.
11. A creasing machine according to any one of claims 6 to 10, wherein said transport drive motor is arranged to be controlled by said control means.
12. A creasing machine according to any one of claims 6 to 11, wherein said transport drive motor is a positional control motor.
13. A creasing machine according to any one of the preceding claims, wherein said control means is programmable, and is constructed and arranged to control the placing and number of creases produced by the machine according to predetermined requirements.