IES84473Y1 - A take-up apparatus for a printing press - Google Patents

Abstract

ABSTRACT An apparatus is disclosed for the take-up of a flexible web, the apparatus compri sing a driven pinch roller through which the web is fed and a plurality of driven mendrels to receive the web from the pinch roller. The pinch roller is operable to substantially maintain the tension in the web as the web is transferred from one of the driven mandrels to another of the driven mandrels.

Description

A Take-Up Apparatus for a Printing Press S 8 4 4 7 3 The present invention relates to roll—to—roll rotary printing devices, in particular to apparatuses for the take—up of the printed material or web.

Rotary printers are well known apparatuses used for the printing of paper or plastic. Roll—to—roll apparatuses are those in which a roll of material is fed into a and is then rewound into a printing unit, is printed, roll as it exits the machine.

Traditional take—up methods involve the printed material exiting the printer, being fed through one or more guide rollers, and then being attached to the take—up roller.

One of the major disadvantages of this method is that once the take-up roller is full, the entire printing process has to be halted. The print feed must be disconnected from the roller, the full take-up roller removed and replaced by an empty roller, the print feed attached, and the process restarted. This procedure results in loss of productivity, due to the downtime of the printing apparatus, and a complicated procedure having to be performed under time pressure. Extra wear and tear is produced on the printing apparatus, due to the frequent stopping and starting of the apparatus.

Considerable wastage of material occurs due to cast- otfs generated during the transferral process.

Therefore, it is an object of the present invention to enable the rapid transfer between take—up rolls without halting the printing machine.

Accordingly, there is provided an apparatus for the take—up of a flexible web, said apparatus comprising a driven pinch roller through which a web is fed and a plurality of driven mandrels to receive the web from the pinch roller, said pinch roller being operable to substantially maintain the tension in said web as said web is transferred from one of said driven mandrels to another of said driven mandrels.

Preferably, said apparatus comprises means for dynamically adjusting the speed of said driven mandrels and of said driven pinch roller.

Preferably, receiving rollers to receive said web are releasably mounted on said driven mandrels.

Preferably, said apparatus comprises means to halt the rotation of a receiving roller to be removed.

There is also provided a method for the transfer of a flexible web between take—up rolls, said method involving the steps of: feeding said web through a pinch roller to a take- up roll; severing said web between said pinch roller and said take—up roll; and attaching the severed end of said web to an empty take—up roll; wherein said pinch roller is driven to substantially maintain the tension in said web as said web is transferred.

Preferably, the steps of severing and attaching are carried out while said web is in motion.

The invention will now be further illustrated by the following description of embodiments thereof, given by way of example only, with reference to the following figures, in which: Fig. 1 is a side View of an apparatus according to the invention; Fig. 2 is a perspective view of the apparatus of Fig. 1 as a take—up roll is nearing completion; and Fig. 3 is a perspective view of the apparatus of Fig. 1 after transferral of the web has been completed.

Referring to Fig. 1, a take—up apparatus for a printing press is indicated generally at 10. The apparatus 10 comprises a box—like housing 12. The apparatus 10 is used in conjunction with a printing press (not shown).

The apparatus 10 is situated at that end of the printing press from which the printed material 16 exits.

A pair of pinch rollers 18a, 18b are mounted on the housing 12 towards the side adjacent to the printing press such that the print feed 16 travelling in the machine direction (indicated by the arrow labelled “from printing machine”) is received by the pinch rollers. The lower pinch roller 18b is driven by a motor to match the speed of the print feed 16, and runs in the direction indicated. The print feed 16 is fed through the pinch rollers 18a, 18b, with the driven pinch roller 18b serving to draw the print feed 16 through the pair of pinch rollers.

It will be understood that said pinch rollers 18a, 18b can be disengaged from each other to facilitate the initial passing through of the print feed 16.

An upper mandrel 20a and a lower mandrel 20b are mounted on the roller face 14 at the opposite side to the pinch rollers 18a, 18b. The mandrels 20a, 20b are driven at the same speed as the driven pinch roller 18b, and in the directions indicated. The mandrels 20a, 20b removably receive take—up rolls 22a, 22b. Either take—up roll 22a, 22b can receive the completed print feed 16, which is then wound around the roll in question.

The apparatus 10 also includes means for altering the speed of the apparatus. In the shown embodiment, the means is in the form of a two—stage switch 24. The switch is connected to the motors of the apparatus 10, and also of the printing press. This allows the operator to change the speed at which the driven pinch roller 18b and the two mandrels 20a, 20b rotate at, as well as altering the speed at which the print feed 16 is produced by the printing press. The operator can change between “HI”, or the normal operating speed of the printing press, and “LO”, which is referred to as the changeover speed and is slower than the normal speed of the apparatus. the transfer of the With reference to Figs. 2 & 3, print feed between take—up rollers is now described.

In Fig. 2, it can be seen that the lower take—up roller 22b is connected to the print feed 16 and is nearing capacity. The roller will need to be changed. As described above, previous methods would involve the stopping of the entire printing process while the print feed is cut, the full take—up roller removed, and the new take—up roller attached and connected to the print feed.

In the present invention, the operator adjusts the speed of the print feed 16 by changing the switch 24 from the “HI” to the “LO” setting. This also slows down the speed of the driven pinch roller 18b and of the two take—up rollers 22a, 22b. The operator then severs the print feed 16 at a point between the pinch rollers 18a, 18b and the full take-up roller 22b, creating a free end 26 to the print feed 16.

The operator then quickly connects or wraps the free end 26 about the empty take—up roller 22a, which proceeds to wind the print feed at the slower speed.

The presence of the pinch rollers 18a, 18b maintains the tension in the print feed 16 from the printing press, preventing the feed 16 from unwinding, slackening, or fouling during transfer.

Once the feed 16 has been transferred to the empty take-up roller 22a, the full take—up roller 22b can be removed, and replaced with an empty roller for future transfer. Once the replacement has been completed, the operator then can restore the switch to the “HI” position, to restore the speed of the whole process to normal.

The two alternate paths of the print feed 16 are shown in Fig. 1.

The invention is not limited to the embodiment described herein, and may be changed without departing from the scope of the invention.

Claims (5)

Claims

1. An apparatus for the take-up of a flexible web, said apparatus comprising a driven pinch roller through which a web is fed and a plurality of driven mandrels to receive the web from the pinch roller, said pinch roller being operable to substantially maintain the tension in said web as said web is transferred from one of said driven mandrels to another of said driven mandrels.

2. An apparatus as claimed in claim 1, wherein the apparatus comprises means for dynamically adjusting the speed of said driven mandrels and of said driven pinch roller.

3. An apparatus as claimed in claim 1 or 2, wherein the apparatus comprises receiving rollers to receive said web, the receiving rollers releasably mounted on said driven mandrels.

4. A method for the transfer of a flexible web between take-up rolls, said method involving the steps of: feeding said web through a pinch roller to a take- up roll; severing said web between said pinch roller and said take—up roll; and attaching the severed end of said web to an empty take—up roll; wherein said pinch roller is driven to substantially maintain the tension in said web as said web is transferred.

5. A method as claimed in claim 4, wherein the steps of severing and attaching are carried out while said web is in motion.