Processing paper and other webs

Abstract: A printing apparatus has an array of cartridges (40,41,42) for printing a web (2) of e.g. paper passing through the array, and one or more units (48,49) contain­ ing printing medium. The cartridges (40,41,42) each are capable of transferring the printing medium from the unit(s) (48,49) to the web (2). The unit(s) (48,49) and the cartridges (40,41,42) of the array are relatively movable, to allow the unit(s) (48,49) to interact success­ ively with at least two of the cartridges (40,41,42). In this way it is possible to change printing from one cartridge (40,41,42) to another, allowing changes to be made to what is printed, without halting the movement of web (2) significantly. The present invention also proposes that the cartridges (40,41,42) may have printing cylinders (43,44,45,46) of different sizes, and furthermore that a mobile unwind stand may be used to move web material to the printing apparatus, and the web output from the printing apparatus processed by sheet folding techniques.

Description: The present invention relates to web processing systems, which may perform operations such as forming an image on a web (e.g. of paper) by printing, copying or other marking process, (hereinafter generally referred to as "printing") and/or handling arrangements such as folding or format adjustment. The present invention is particularly, but not exclusively, concerned with processing systems in which the paper or other material orginates as a continuous web on a roll. It is very well known to pass paper from a roll through a printing machine to form a series of images on it and then rewind, sheet or fold it into various formats. However, there are fundamental problems which provide a serious limitation to the efficiency of such machines. There is the problem of "down-time". Once the printing machine has been set up, and the paper put in motion, printing can occur very rapidly. However, with the known machines (see e.g. EP-A-0 165 599) long delays can occur when any change is made to the method of delivery or to what is being printed. For example, if a different image is to be printed, or if the repeat length of the image is to be changed, or if a different colour is to be used, or the folded format is to be changed, then the print run has to be stopped. The design of the known printing machines is such that it is extremely difficult to make such changes, and hence it is common for the time such machines are not working (the down-time) to be much longer than the effective working time. A further problem of existing arrangements is that printing machines are designed for a specific printing application, the machine being available as a single entity. What this means, in practice, is that if the owner of the machine wants to carry out more complex operations than are currently possible on his machine, he must undertake quite major engineering or buy a whole new machine. The present invention is therefore concerned with overcoming, or at least ameliorating, these problems to design a web processing system in which many changes can be made whilst the system is in operation (can be made "on the fly") and which may also have the advantage of being modular so that the system may be expanded in capability if required. The web processing system with which the present invention is concerned may be divided into three parts. Firstly, there is the part of the system which takes the web from a roll or reel and feeds it to the rest of the system. Secondly, there is the part which forms an image on the web, and thirdly there is a handling arrangement for the printed web. The present invention is concerned with the third part of such a system. The present invention concerns the relationship between the printing arrangement and the subsequent web handling. The printing industry has developed in two directions. One of them is concerned with the handling of elongate webs, such as described above, whilst the other is concerned with handling material in sheet form. In general, each type has its associated problems, and workers in the art tend to concentrate on their own field. It has been realised, however, that the problems of folding occurring in the field of elongate web handling can be effectively solved using techniques from the sheet handling field, which techniques have been evolved to handle the products of a sheet-fed printing machine. Therefore, the present invention proposes that the output of a web printing machine is cut into sheets and is fed to a sheet folding system operating in a un-timed relationship. Thus this invention may provide a method of processing at least one web of material comprising printing on the at least one web; cutting, in a timed relationship with the printing, the or each printed web into a plurality of separate sheets; and folding each sheet by a folding means whose action is timed in dependence on the arrival of a sheet at the folding means and independently of the action of printing on the at least one web; wherein there is continuous movement of the material from prior to the printing to the commencement of the folding of the sheets. This invention may also provide a method of processing at least one web of material, comprising printing on the at least one web; forming a longitudinal fold in the or each printed web; cutting, in a timed relationship with the printing, the or each web into a plurality of separate sheets; and folding each sheet by a folding means whose action is time in dependence on the arrival of a sheet at the folder and independently of the action of printing on the at least one web. Furthermore, this invention may provide a method of processing at least one web of material, comprising printing the at least one web; forming transverse perforations in the printed web; cutting, in a timed relationship with the printing, of the or each web into a plurality of separate sheets; and folding each sheet by a folding means whose action is timed in dependence on the arrival of a sheet at the folder and independently of the action of the printing on the at least one web. In a similar way, the present invention may provide a web processing system comprising an apparatus for printing continuously at least one web of material; means for transferring the printed web continuously to a means for cutting the web into a plurality of separate sheets, which means has an action having a timed relationship with the printing apparatus and means for transferring the sheets continuously to a means for folding the sheets, which folding means has an action which is timed in dependence on the arrival of a sheet at the folding means and independently of the action of printing on the at least one web. The present invention may further provide a web processing system comprising an apparatus for printing at least one web of material; means for forming a longitudinal fold in the or each web; means for cutting the web into a plurality of separate sheets, and means for folding the sheets, which folding means has an action which is timed in dependence on the arrival of a sheet at the folding means and independently of the action of printing on the at least one web. The present invention may provide a web processing system comprising an apparatus for printing at least one web of material; means for forming a transverse perforation in the or each web; means for cutting the web into a plurality of separate sheets, and means for folding the sheets, which folding means has an action which is timed in dependence on the arrival of a sheet at the folding means and independently of the action of printing on the at least one web. Once the web has been cut, it can be fed to a buckle, knife, or combination folder which may perform various known folding operations on each sheet. This is particularly advantageous when handling lightweight stock, at least not unless they run at very reduced speeds. However, it is easy to make an initial fold in the web from the web printing machine, thereby stiffening the material. It also becomes possible to provide a perforation for the first fold made by the folding machine. Embodiments of the invention will now be described in detail, by way of example, with reference to the accompanying drawings, in which: Fig. 1 shows a general view of a paper handling system with which the present invention is concerned; Figs. 2 and 3 show alternative paper folding systems; Fig. 4 shows one form of processing and folding paper from a web printing machine, embodying the present invention; and Fig. 5 shows an alternative paper processing arrangement. Referring first to Fig. 1, a web (in this example, paper) handling system with which the present invention is concerned involves three parts. A first part, generally indicated at 1, takes paper from one or more paper rolls in the form of a web 2 and transports it to a printing unit 3 and an optical drying unit 4. As illustrated in Fig. 1, a right-angled turn in the paper web 2 is achieved by passing the paper round an angled bar 5. After passing through the printing unit 3, and the drying unit 4, the paper web 2 is again turned for convenience through 90° via bar 6, and passed to a cutting and folding arrangement generally indicated at 7. Sheets of paper printed, cut and folded as appropriate then pass for e.g. stacking in the direction indicated by the arrow 8. Of course, any arrangement of paper web input unit 1, printing station 3, drying station 4, and cutting and folding arrangement 7 may be provided, the actual configuration depending on space and similar constraints. As discussed above, the present invention is concerned with various developments of the components of this system. Once the paper web has been printed, then this invention comes into play. In most cases, the possibilities for folding of paper whilst in web form are limited (although one or more longitudinal folds may be made as will be described later), but few complicated folding combinations are practicable with the output from web printing machines. On the other hand, there are various techniques for folding paper sheets in e.g. gate folds, multiple transverse folds and longitudinal folds; two are illustrated in Figs. 2 and 3. Fig. 2 shows an arrangement known as a knife folder in which the paper sheet 160 passes over a pair of contra-rotating rollers 161, 162. With the sheet 160 stationary in that position, a knife 163 is lowered, forcing the sheet 160 into the "nip" 164, thereby providing a firm fold. The sheet 160 is then drawn between the rollers 161, 162 for subsequent use. The knife 163 will normally be connected to a photocell or similar detector which detects the presence of sheet 160 below the knife. In this way the folding operation can be synchronised with the arrival of the paper sheet 160 at the folder, rather than synchronised with e.g. an earlier stage of the printing operation. Fig. 3 shows an arrangement known as a buckle folder in which a sheet of paper 170 passes between a first pair of contra-rotating rollers 171,172 and its leading edge strikes a ramp 173. The action of the rollers 171,172 forces the paper sheet 170 up the ramp 173 until its leading edge strikes a stop 174, the position of which is determined by the desired position of the fold. When paper strikes the stop 174, it can no longer move up the ramp, and so the action of rollers 171,172 is to force the paper sheet 170 into the nip defined between roller 172 and another roller 175. This forms a sharp fold in the paper, which then passes downwardly due to the action of rollers 172 and 175. It may then strike another ramp 176 and move downwardly to another stop 177. In this position the sheet 170 is then acted on by rollers 175 and 178, between which is another nip causing further folding. It is also possible to perforate the folded paper longitudinally by passing it through a perforating nip formed by rollers 179. Thus, the system in Fig. 3 permits successive transverse folding and perforating of the sheet, and by providing several such units with one or two ramps, any number of transverse folds may be provided. If the direction of movement of the sheet is changed between one buckle folder and the next, both longitudinal and transverse folds may be provided. However, the first fold is generally a transverse one, or extra equipment would be needed. Again the folding of the sheet 170 is in timed dependence on its arrival at the folder, not in dependence of the timing of the printing operation. It is also possible to provide folders which are a combination of knife and buckler folders. Referring now to Figs. 4 and 5 a paper web 2 from a web printing machine is cut into sheets by a knife arrangement 180. Fig. 4 shows a persepctive view of the arrangement, and the web 2 from the printing machine is first turned through 90° by a bar 6 as has already been described with reference to Fig. 1. Of course, this is not essential and the web path to the knife arrangement 180 may be straight as shown by dotted lines in Fig. 4. This knife unit 180 may be powered from a drive shaft common with the printing station. A drier unit may also be provided as discussed with reference to Fig. 1. Once the knife arrangement 180 has cut the web 2 into sheets, they may be passed to a folder 181 which may be e.g. a buckle folder such as shown in Fig. 3, although a knife folder as shown in Fig. 2 may also be used. One factor to bear in mind is that the speed of the web from the printing machine may be faster than can be handled by the known sheet folding systems, and it may be necessary to divide the sheet flow so that sub-streams follow two or more routes. In this example a divider 183 is provided so that some sheet pass straight onto the folder 181, and others are diverted to another folder 182. Further changes in direction may occur at units 184 and 185. Such two-route handling of paper sheets is known, and therefore it is unnecessary to discuss it in greater detail here. Clearly, it is possible to provide for any number of folds, depending on the use to which the paper is to be put. Whereas, as explained above, the first fold is generally a transverse fold in sheet fed systems. Fig. 5 shows a simple way of providing a first, longitudinal, fold in the paper. This is particularly important with thin paper which cannot easily be handled by buckle folders such as shown in Fig. 3. The paper web 2 from the printer machine and (possibly) the drier passes to a former 190 which is triangularly shaped so that a longitudinal fold is placed in the paper as it moves downwardly from a roller 191 to a pair of guide rollers 192, between which a throat is formed. Thus, the paper fed to a buckle folder generally indicated at 193 has already been folded once, in the longitudinal direction, and is therefore less subject to malfunctioning in the folder. Again, however, a knife or similar cutter 194 has to be provided before the web enters the buckle folder 193. As described above, the folds are made directly to the paper. However, to ease the transverse folding, a transverse perforating unit 195 may be provided upstream of the knife or other cutter 194. Furthermore, the use of a web printer permits longitudinal perforation to facilitate the longitudinal folding shown in Fig. 5, by means of the continuous perforating wheel 196 producing perforations 197. Furthermore, this wheel 196 may be powered from the main drive shaft to the printing station. Likewise, any other longitudinal fold can be produced on a continuous basis. Perforation also assists quality by permitting air to escape from within the fold.

Claims: A method of processing at least one web (2) of material comprising printing (3) on the at least one web (2); cutting (194), in a timed relationship with the printing (3), the or each printed web (2) into a plurality of separate sheets; and folding each sheet by a folding means (181,182,193); there being continuous movement of the material from prior to the printing to the commencement of the folding of the sheets; characterised in that: the folding means (181,182,193) has an action which is timed in dependence on the arrival of a sheet at the folding means (181,182,193) and independently of the action of printing (3) on the at least one web (2). A method according to claim 1, further including forming a longitudinal fold (197) in the or each web (2) prior to cutting the web (2) into the sheets. A method of processing at least one web (2) of material, comprising printing (3) on the at least one web (2); forming (190) a longitudinal fold in the or each printed web (2); cutting (194), in a timed relationship with the printing (3), the or each web into a plurality of separate sheets; and folding each sheet by a folding means (181,182,193); characterised in that: the folding means (181,182,193) has an action which is timed in dependence on the arrival of a sheet at the folding means (181,182,193) and independently of the action of printing (3) on the at least one web (2). A method according to claim 2 or claim 3, wherein a longitudinal perforation (196) is formed in the or each web (2) prior to the formation of the longitudinal fold. A method according to any one of claims 2 to 4, wherein transverse perforations are formed (195) in the or each web (2) prior to cutting the or each web (2) into the sheets. A method of processing at least one web (2) of material, comprising printing (3) the at least one web (2); forming transverse perforations (195) in the printed web; cutting (194), in a timed relationship with the printing, of the or each web (2) into a plurality of separate sheets; and folding each sheet by a folding means (181,182,193); characterised in that: the folding means (181,182,193) has an action which is timed in dependence on the arrival of a sheet at the folding means (181,182,193) and independently of the action of printing (3) on the at least one web (2). A method according to any one of claims 1 to 6, wherein after cutting the or each web into sheets, alternate sheets are directed (183) to separate folding locations, where the sheets are folded. A web processing system comprising an apparatus (3) for printing continuously at least one web (2) of material; means for transferring the printed web continuously to a means (194) for cutting the web into a plurality of separate sheets, which cutting means (194) has an action having a timed relationship with the printing apparatus (3); and means for transferring the sheets continuously to a means (181,182,193) for folding the sheets; characterised in that: the folding means (181,182,193) has an action which is timed in dependence on the arrival of a sheet at the folding means (181,182,193) and independently of the action of printing (3) on the at least one web (2). A web processing system according to claim 8, having means (197) between the printing apparatus (3) and the cutting means (194) for forming a longitudinal fold in the or each web (2). A web processing system comprising: an apparatus (3) for printing at least one web (2) of material; means (197) for forming a longitudinal fold in the or each web (2); means (194) for cutting the web (2) into a plurality of separate sheets; and means (181,182,193) for folding the sheets; characterised in that: the folding means (181,182,193) has an action which is timed in dependence on the arrival of a sheet at the folding means (181,182,193) and independently of the action of printing on the at least one web. A web processing system accordingly to claim 9 or claim 10, having means (196) for forming a longitudinal perforation in the or each web (2) prior to the formation of the longitudinal fold. A web processing system according to any one of claims 8 to 11, having means (195) for forming a transverse perforation in the web (2) prior to the cutting of the web (2) into sheets. A web processing system comprising: an apparatus (3) for printing at least one web (2) of material; means (195) for forming a transverse perforation in the or each web (2); means (194) for cutting the web (2) into a plurality of separate sheets, and means (181,182,193) for folding the sheets; characterised in that: the folding means (181,182,193) has an action which is timed in dependence on the arrival of a sheet at the folding means (181,182,193) and independently of the action of printing on the at least one web (2). A web processing system according to any one of claims 8 to 13, wherein the means (181,182,193) for folding the sheets includes a buckle folder. A web processing system according to any one of claims 8 to 14, wherein between the cutting means (194) and the means (181,182,193) for folding the sheets, means (183) are provided for directing alternate sheets to a corresponding one of two folders (181,182) of the folding means.

Inventors: BOWMAN KENNETH ALBERT, GODDEN DAVID, MASLIN ROGER FREDERICK, RIPPER JONATHAN HEATH, BOWMAN, KENNETH ALBERT, GODDEN, DAVID, MASLIN, ROGER FREDERICK, RIPPER, JONATHAN HEATH
Applicants: STRACHAN & HENSHAW MACHINERY, STRACHAN HENSHAW MACHINERY LIMITED
Application year: 1987
Main classification: B41F13
IPC codes: B41F13, B41F31, B41F7, B65H19