Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B26—HAND CUTTING TOOLS; CUTTING; SEVERING
  • B26F—PERFORATING; PUNCHING; CUTTING-OUT; STAMPING-OUT; SEVERING BY MEANS OTHER THAN CUTTING
  • B26F1/00—Perforating; Punching; Cutting-out; Stamping-out; Apparatus therefor
  • B26F1/18—Perforating by slitting, i.e. forming cuts closed at their ends without removal of material
  • B26F1/20—Perforating by slitting, i.e. forming cuts closed at their ends without removal of material with tools carried by a rotating drum or similar support
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B26—HAND CUTTING TOOLS; CUTTING; SEVERING
  • B26D—CUTTING; DETAILS COMMON TO MACHINES FOR PERFORATING, PUNCHING, CUTTING-OUT, STAMPING-OUT OR SEVERING
  • B26D1/00—Cutting through work characterised by the nature or movement of the cutting member or particular materials not otherwise provided for; Apparatus or machines therefor; Cutting members therefor
  • B26D1/01—Cutting through work characterised by the nature or movement of the cutting member or particular materials not otherwise provided for; Apparatus or machines therefor; Cutting members therefor involving a cutting member which does not travel with the work
  • B26D1/12—Cutting through work characterised by the nature or movement of the cutting member or particular materials not otherwise provided for; Apparatus or machines therefor; Cutting members therefor involving a cutting member which does not travel with the work having a cutting member moving about an axis
  • B26D1/25—Cutting through work characterised by the nature or movement of the cutting member or particular materials not otherwise provided for; Apparatus or machines therefor; Cutting members therefor involving a cutting member which does not travel with the work having a cutting member moving about an axis with a non-circular cutting member
  • B26D1/34—Cutting through work characterised by the nature or movement of the cutting member or particular materials not otherwise provided for; Apparatus or machines therefor; Cutting members therefor involving a cutting member which does not travel with the work having a cutting member moving about an axis with a non-circular cutting member moving about an axis parallel to the line of cut
  • B26D1/40—Cutting through work characterised by the nature or movement of the cutting member or particular materials not otherwise provided for; Apparatus or machines therefor; Cutting members therefor involving a cutting member which does not travel with the work having a cutting member moving about an axis with a non-circular cutting member moving about an axis parallel to the line of cut and coacting with a rotary member
  • B26D1/405—Cutting through work characterised by the nature or movement of the cutting member or particular materials not otherwise provided for; Apparatus or machines therefor; Cutting members therefor involving a cutting member which does not travel with the work having a cutting member moving about an axis with a non-circular cutting member moving about an axis parallel to the line of cut and coacting with a rotary member for thin material, e.g. for sheets, strips or the like
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B26—HAND CUTTING TOOLS; CUTTING; SEVERING
  • B26D—CUTTING; DETAILS COMMON TO MACHINES FOR PERFORATING, PUNCHING, CUTTING-OUT, STAMPING-OUT OR SEVERING
  • B26D1/00—Cutting through work characterised by the nature or movement of the cutting member or particular materials not otherwise provided for; Apparatus or machines therefor; Cutting members therefor
  • B26D1/56—Cutting through work characterised by the nature or movement of the cutting member or particular materials not otherwise provided for; Apparatus or machines therefor; Cutting members therefor involving a cutting member which travels with the work otherwise than in the direction of the cut, i.e. flying cutter
  • B26D1/62—Cutting through work characterised by the nature or movement of the cutting member or particular materials not otherwise provided for; Apparatus or machines therefor; Cutting members therefor involving a cutting member which travels with the work otherwise than in the direction of the cut, i.e. flying cutter and is rotating about an axis parallel to the line of cut, e.g. mounted on a rotary cylinder
  • B26D1/626—Cutting through work characterised by the nature or movement of the cutting member or particular materials not otherwise provided for; Apparatus or machines therefor; Cutting members therefor involving a cutting member which travels with the work otherwise than in the direction of the cut, i.e. flying cutter and is rotating about an axis parallel to the line of cut, e.g. mounted on a rotary cylinder for thin material, e.g. for sheets, strips or the like
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B26—HAND CUTTING TOOLS; CUTTING; SEVERING
  • B26D—CUTTING; DETAILS COMMON TO MACHINES FOR PERFORATING, PUNCHING, CUTTING-OUT, STAMPING-OUT OR SEVERING
  • B26D5/00—Arrangements for operating and controlling machines or devices for cutting, cutting-out, stamping-out, punching, perforating, or severing by means other than cutting
  • B26D5/20—Arrangements for operating and controlling machines or devices for cutting, cutting-out, stamping-out, punching, perforating, or severing by means other than cutting with interrelated action between the cutting member and work feed
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B26—HAND CUTTING TOOLS; CUTTING; SEVERING
  • B26D—CUTTING; DETAILS COMMON TO MACHINES FOR PERFORATING, PUNCHING, CUTTING-OUT, STAMPING-OUT OR SEVERING
  • B26D5/00—Arrangements for operating and controlling machines or devices for cutting, cutting-out, stamping-out, punching, perforating, or severing by means other than cutting
  • B26D5/20—Arrangements for operating and controlling machines or devices for cutting, cutting-out, stamping-out, punching, perforating, or severing by means other than cutting with interrelated action between the cutting member and work feed
  • B26D5/30—Arrangements for operating and controlling machines or devices for cutting, cutting-out, stamping-out, punching, perforating, or severing by means other than cutting with interrelated action between the cutting member and work feed having the cutting member controlled by scanning a record carrier
  • B26D5/32—Arrangements for operating and controlling machines or devices for cutting, cutting-out, stamping-out, punching, perforating, or severing by means other than cutting with interrelated action between the cutting member and work feed having the cutting member controlled by scanning a record carrier with the record carrier formed by the work itself

Definitions

• the present invention relates to perforators as used in continuous web printers, and more particularly to perforators that form a line of perforations which extend across the direction of movement of the web.
• perforators are used as sub-assemblies in web printing systems, for example to form a line of perforations for a tear-off section of a business form, a manually removable coupon in an advertising print, or other such applications wherein printed matter is required to have a portion or sub-part which is to be cleanly separable from another portion or sub-part.
• one approach to perforation of the printed work is to run the web between a pair of opposed rollers, one of which is a hard steel backing roller, and the other of which, called a perf roller, carries a narrow-bladed knife positioned so that it rotates into contact with the paper and perforates the paper at a nip formed with the backing roller.
• Both the backing roller and the perf roller are coupled, by fixed mechanical gearing or otherwise, such that they rotate in opposite senses but with an identical peripheral speed, which is set equal to the web speed.
• a perforation assembly wherein a backup roller is placed on one side of a web, and a perf knife is rotatably held on the opposite side at a home position out of contact with the roller.
• the backup roller runs at a constant surface speed which is substantially matched to that of the web; the web, in turn, is tensioned around the backup roller and supported thereon.
• a servo motor propels the perf knife up into a position to engage the web at the backup roller, and the knife is driven by engagement with the backup roller so that it continues to rotate in engagement with the backup roller, past the nip position, perforating the web.
• the perf knife then continues to rotate further, out of engagement with the web, until it reaches a sensor which triggers a reversal of servo motor current to apply braking torque to the knife.
• the knife then comes to rest at a home position, ready to commence another cycle of operation.
• the backup roller thus serves as an energy-storage mechanism which engages and maintains the perf knife at speed once the perf knife has been moved to the engagement point adjacent the nip region.
• the servo motor which drives the perf knife need only apply a sufficiently large torque impulse to bring the knife quickly intc engagement at an adequate speed which approximates the web speed, and thereafter apply reverse braking torque between the brake point and home position.
• the servo also continues to accelerate the knife after it passes the nip and until it reaches the brake point, thereby reducing the overall recycling period.
• the backing roller may rotate on a different, preferably larger, circumferential diameter than the perf knife, and the inertia of the perf knife holder may therefore be significantly reduced.
• the holder need only have sufficient bending rigidity to maintain the perforation force along the width of the web, and need have neither a large diameter, a solid body, nor the high inertia of a mechanically coupled gear train. This allows the perf blade to engage with a quick response time, to recycle to home position with a relatively quick recovery time, and to be actuated in arbitrary phase relation to the rotation of the backup roller, and at arbitrarily selected instants as the web passes adjacent thereto.
• a preferred system employing the invention is an electrographic print system, wherein images are generated by electrically controlled latent imaging or direct printing, for example, using a multi-electrode printing cartridge driven by an imagewise series of generally multiplexed electrical drive signals.
• a number of common printers have this construction such as "ionographic or charge transfer" printers, laser printers and more generally, electrographic printers.
• line synchronization signals available from the imaging portion of the printer provide, with appropriate offset, the control signal for initiating perf knife actuation.
• Figure 1 shows a print system of the prior art
• Figure 2 shows a prior art perforation assembly such as used in the system of
• FIG. 3 illustrates one embodiment of the perforation assembly of the present invention
• Figure 4 illustrates rotational velocity in a representative cycle of the perforation assembly of Figure 3.
• Figures 5, 5 A and 5B illustrate a perf blade holder adapted to the assembly of Figure 3.
• the structure and advantages of the present invention will be best understood after a consideration of prior art printing and perforation systems as illustrated in Figures 1 and 2.
• the prior art system 1 shown in Figure 1 involves a generally extensive mechanical assembly in which a large supply roll WR of web material, such as newsprint or other paper, provides a web W of continuous print substrate which extends through the assembly 1 past one or more printing stations, 10, 20... at which graphics or text images are applied to the web, and proceeds through a perforator 50 which perforates, punches, or otherwise carries out mechanical operations on the web short of physically separating the web into sheets.
• the web then passes into a cutter/handling assembly 60 which may cut the web into sheets of a standard size, e.g. book, booklet, or newspaper size sheets, and may also stack, fold, sort, bind, or otherwise handle tie final output of the printer.
• perforations are commonly applied across the web, or parallel to the direction of travel, or both.
• Cross-web perforations are commonly used where a section of a paper or form is to be manually torn off and used as a separate document, such as an entry blank, a ticket, or a return form.
• Perforations running in the direction of travel may serve a similar function, and may be used together with cross-web perforations to define rectangular tear-out sections such as small coupons, graphic windows, or other bounded generally rectangular segments.
• Figure 2 illustrates a representative prior art perforation assembly for placing cross-web perforations in the moving web.
• a perforation knife 2 which is essentially a sharp comb is secured in a first roller A and a second or backup roller B is mounted in a rigid frame opposite to the rol er A.
• the rollers are driven at the web speed, and a pair of drive gears, Gl , G2, attached to the respective rollers couple the rollers so that they always move synchronously, i.e. at the same speed as the web and in counterclockwise and clockwise directions such that the nip between the two rollers defines a substantially stationary contact region.
• a pair of drive gears, Gl , G2 attached to the respective rollers couple the rollers so that they always move synchronously, i.e. at the same speed as the web and in counterclockwise and clockwise directions such that the nip between the two rollers defines a substantially stationary contact region.
• such an arrangement is characterized by high inertia, and because the perf blade is fixed in a synchronously operated roller, has limited flexibility as regards timing and spacing of per
• FIG. 3 shows a cross-web perforation assembly 55 in accordance with the present invention.
• Assembly 55 includes a backup roller 56 around which the web is positioned to wrap by idler rollers 57a, 57b, and a perf knife assembly 58 opposed to the backup roller.
• the perf knife assembly 58 includes a fixed mounting 60 such as a frame with a pair of pillow blocks for securing shaft bearings at a defined position across from roller 56, and a pivoting knife holder 62 which holds and adjustably positions a perf knife 65 so that it can rotate up against the web and perforate it as the web passes over the backup roller 56.
• the rotating holder 62 provides a support of high bending stiffness to hold the perf knife straight.
• It may be a shaft such as a steel shaft of diameter approximately one inch having a groove therein in which the perf blade and a plurality of adjusting clamp screws and adjusting jacks are fitted.
• the details of mounting the perf blade in such a roller are well known, and are similar to constructions as employed, for example, to hold planer blades in molding planes or wood jointing machines, and need not be described in detail here.
• the perf knife is mounted so as to contact the backing roller 56 uniformly, and is a somewhat flexible blade made of thin spring steel sheet, which is adjusted to have a preload of approximately one to ten mils against the backup roller, thus assuring that the knife dependably presses with sufficient force to perforate the thin web across the full width of the knife blade.
• a source of motive power is provided to the backup roller 56 to maintain it rotating in direction R at a constant speed substantially equal to the web speed.
• the rotatable knife holder 62 is not coupled to roller 56 but instead lies in a resting state with the perf blade 65 contacting neither the web nor the backup roller.
• Perf blade 65 extends outward from the pivot point (not numbered) by a distance greater than the separation of that pivot point from the surface of roller 56, and lies generally at a home position that is close to, but not contacting, the web W.
• a servo motor S indicated in phantom is connected to the rotatable blade-holder 62, and is electrically actuated to rotate the blade upward into engagement.
• the blade itself is made of spring steel which may for example have a thickness of approximately .65 millimeters, and height of approximately 2.3 centimeters, and in a representative embodiment extends for a length of approximately 26 centimeters, slightly more than the width of the web W.
• This blade is a flexible saw-like or comb toothed blade set in a bearing-mounted shaft which in one prototype embodiment had a maximal outer diameter of approximately thirty-six millimeters, less than half the diameter of the backup roller 56.
• the backup roller 56 had a mass over four times as great as the blade holder 62, with an even higher disparity in rotational inertia.
• This disparity in size allows the backup roller to couple energy into the pivoting holder 62 without slowing substantially when the perf blade 65 engages the web, and to carry the perf blade along substantially synchronously with the web despite the absence of direct drive coupling between the rollers.
• the perf blade is of thin spring steel, and may flex and bend as it engages the roller 56 thus assuring that it maintains a high degree of pressure along the entire perforation line through the web without having so high a degree of rigidity as to rip the delicate web as it travels.
• Operation of the perf blade proceeds as follows.
• the servo motor S is actuated to rotate shaft 62 up from the home position and quickly bring the perf blade 65 up to approximately the rotational speed of backup roller 56.
• the blade engages the web and the backup roller 56 and is carried along by motion of the web, undergoing additional angular acceleration so that it moves synchronously into and past the c ontact nip and out of engagement with the web.
• the knife passes a first sensor 68 located in the housing 58 and this triggers a control circuit which reverses the current applied to the servo motor S.
• the servo motor S therefore brakes the shaft rotation, progressively slowing it down.
• a second sensor 69 detects its presence and an electromagnetic lock is applied to the servo motor to lock the holder 62, securing the knife in position at or just beyond the sensor 69.
• This stopping position is approximately ⁇ /6 radians below the point at which the perf blade would engage the web, a location sufficiently close to the web that the blade may be quickly accelerated into an operative position.
• the complete cycle from servo motor advance, through perforation to braking and return to home position can be effected in approximately 90 milliseconds, allowing perforation to be effected up to about 10 times per second as the web moves therepast.
• the blade By locking the device in the home positi an, the blade is maintained ready at a fixed location to be propelled into engagement with the backup roller, and the servo motor may be repeatedly driven to effectively bring the blade into engagement with the web at a precise instant in time, with an accuracy on the order of a millisecond or less. This has proven to be sufficiently accurate to place perforations within the tolerance band for perforations which is currently accepted in the industry today.
• Figure 4 shows the movement of the perf blade holder during a representative cycle.
• the absc issa plots velocity, while the ordinate plots time or rotational position, with angle of the blade, starting at a home position of zero degrees, indicated at selected points.
• the origin is 31° before the web contact portion.
• the blade holder starts off resting at the home position and is accelerated by the servo S until it rotates 31 °, at which time the perf blade engages the web.
• the web is carried synchronously with or by the backup roller, which in this prototype was a 2.940 inch diameter hardened steel roller moving at 178 RPM, i.e., a surface speed of 27.5 inches/second.
• the blade contacted the web at the 31 ° position, it engaged the backup roller and despite the energetic impulse of perforation impact was then smoothly carried along at the web speed for approximately 5°, while the idler rolls maintained the web closely in contact with the backup roll, so that no ripping would occur.
• Drive acceleration thereafter continued up to the brake cell, located at 300°.
• the brake position at 300° the stepper drive current was reversed bringing the blade back to a low velocity at the home position where the servo armature was locked to keep the blade stationary.
• the initial drive impulse successfully brings the blade up to an adequate speed and thereafter blade travel is such that ripping of the web cannot occur.
• the entire cycle occupies approximately 90 milliseconds, and the lead time between actuation and perforation represents approximately one-half that interval. This time interval was constant for a fixed servo drive current, varying by no more than about one millisecond. Thus perforation can be laid down at an interval of as little as three and one-half inches at this web speed, with a registration that is within existing industry tolerances.
• the perf holder can complete a cycle before the backup roller has undergone a complete revolution, and may be actuated to perform several perforations on a single page, or to perforate different pages at different locations, allowing much greater flexibility in arranging the print process line or producing final prints, as regards areas such as layout of two-sided copy, design of forms, and other aspects of creating prints.
• the rotary holder 62 is a generally solid cylindrical roller shaft which extends across the width of the web and into which a broad flat face 63 has been formed, for example by milling, to support the perf blade 6.5.
• a plurality of holes 63a extend along the length of face 63 perpendicular to its surface, which are tapped for receiving threaded hold-down bolts, while a second plurality of holes 65a oriented perpendicularly thereto extend through the shaft and are threaded for at least part of their length to accommodate jack screws.
• the jack screw holes lie in the plane of face 63, centered under the blade position, which is indicated by B in the cross- sectioned view, Figure 5A.
• the shaft is also milled flat on the side opposite the blade, forming the face F into which the jack screw holes are drilled. Additional material is removed along an edge 68, further reducing the overall inertial mass of the perf holder assembly 62.
• Figure 5B shows a cross-sectional view of the assembly 6 together with the perf blade 65 and a clamp bar 62a, in a system with a backup roller 56 and guide rollers 57a, 57b.
• the clamp bar is a solid prism of substantially triangular cross section extending the length of face 63 with deep set holes on a spacing matching that of holes 63a for clamping the blade against the face. This provides a rigid support for the perf blade 65, and enhances balance by its approximate symmetry with face 68. It also enhances clearance from the printed face of the web and contributes to the low weight of the assembly.
• the perf roller 62 and backup roller 56 lie on parallel axes in a plane P at a separation such that the perf blade contacts the web just as i t rotates through the plane and contacts roller 56.
• the blade remains in contact with the web only when the web is essentially tensioned flat against roller 56, and it remains in contact for only a short arcuate distance 8 subtending 2-5° of arc, as it is engaged and accelerated by contact.
• the assembly then brakes, and returns to the home position which is shown in Figure 5B.
• Figures 5-5B show a prototype system which is assembled by machining and customizing commonly available elements of metal stock.
• the invention may desirably be practiced with machine elements that are fabricated with less costly manufacturing steps, or with materials specifically selected to enhance the performance of the perforator.
• a several fold reduction of mass and corresponding reduction in cycle time may be obtained by substituting a low weight, e.g., cast magnesium, blade holder for the steel shaft of Figure 5.
• synchronization of the perf actuation with the imaging areas of the web although discussed only briefly, will be understood to be effected by any conventional web-or process- synchronization or registration technique. These may include, for example synchronization with electrical print line signals, synchronization by laying down and detection of registration marks on the web itself, or other techniques.

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• Life Sciences & Earth Sciences (AREA)
• Forests & Forestry (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Perforating, Stamping-Out Or Severing By Means Other Than Cutting (AREA)

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• 1997
  • 1997-09-11 WO PCT/US1997/016077 patent/WO1998012027A1/en not_active Application Discontinuation
  • 1997-09-11 JP JP10514742A patent/JP2001500799A/ja active Pending
  • 1997-09-11 EP EP97941031A patent/EP1047532A1/de not_active Withdrawn
  • 1997-09-11 AU AU42674/97A patent/AU4267497A/en not_active Abandoned

Non-Patent Citations (1)

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