EP0487836A1 - Méthode de réglage thermique pour contrôler l'impression d'une presse à imprimer - Google Patents

Méthode de réglage thermique pour contrôler l'impression d'une presse à imprimer Download PDF

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Publication number
EP0487836A1
EP0487836A1 EP91114491A EP91114491A EP0487836A1 EP 0487836 A1 EP0487836 A1 EP 0487836A1 EP 91114491 A EP91114491 A EP 91114491A EP 91114491 A EP91114491 A EP 91114491A EP 0487836 A1 EP0487836 A1 EP 0487836A1
Authority
EP
European Patent Office
Prior art keywords
bearers
operating
pair
frame
press
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP91114491A
Other languages
German (de)
English (en)
Inventor
Francis John Littleton
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
LITTLETON INDUSTRIAL CONSULTANTS Inc
Littleton Ind Consultants Inc
Original Assignee
LITTLETON INDUSTRIAL CONSULTANTS Inc
Littleton Ind Consultants Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by LITTLETON INDUSTRIAL CONSULTANTS Inc, Littleton Ind Consultants Inc filed Critical LITTLETON INDUSTRIAL CONSULTANTS Inc
Publication of EP0487836A1 publication Critical patent/EP0487836A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41F—PRINTING MACHINES OR PRESSES
    • B41F13/00—Common details of rotary presses or machines
    • B41F13/08—Cylinders
    • B41F13/24—Cylinder-tripping devices; Cylinder-impression adjustments
    • B41F13/34—Cylinder lifting or adjusting devices

Definitions

  • This invention relates to machines in which a first rotating member is maintained in close physical relationship to a second fixed or rotating member and more particularly to a method for thermally controlling the spacing between the bearers of the first and second members such that the machine operates "off-bearer". While the invention is thus broadly applicable, it is disclosed more fully with reference to the printing art to which it is particularly applicable.
  • a web of paper is fed into a printing press where it is passed between a pair of cylinders which print ink images on one or both sides of the web.
  • these printing cylinders are called blanket cylinders.
  • the blanket cylinders are precisely supported for rotation in a rigid frame which maintains a firm pressure between the cylinders.
  • the ink images are transferred to the blanket cylinders by plate cylinders via techniques well known in the art and unimportant to the present invention.
  • the blanket cylinders are connected axially to bearer elements, which in turn are connected by a journal for rotation about bearings.
  • the bearings are fixedly attached to the frame supports, and the distance between bearings is fixed prior to operation of the press.
  • the blanket and plate cylinders are slightly undercut from their respective bearers causing each pair of bearers to engage the other pair of bearers.
  • Frictional force also causes greater wear on the bearers and bearings.
  • the contact between bearer elements is aggravated during operation of the press by the expansion of the bearer elements due to centrifugal forces created by high speed operation.
  • the temperature of the bearers tends to increase causing further expansion and bowing of the cylinders. This expansion by heat and erosion of the bearers by friction seriously hampers attempts to keep the press positioned to maximize print quality and efficiency.
  • the problems involved with operating a web offset press "off-bearer" at high printing speeds are overcome by a method for thermally controlling the space between bearers. Additionally, the problem of print inefficiencies associated with non-bearered or Flexo presses is also overcome by the disclosed method.
  • the pressure between a blanket cylinder and a plate cylinder can be controlled by a thermal adjusting apparatus operating on the frame which supports the cylinders as disclosed in U.S. Patent No. 4,426,897.
  • the method disclosed in the '897 patent did not completely cure the problems of the plate and blanket cylinders bowing out at the edges due to the increased heat and increased load caused by friction between bearer elements, nor was it appreciated how the '897 invention could be applied to operating an offset press off-bearer.
  • the present invention provides a method of thermally controlling the distance between the bearer elements such that a fixed space is maintained between the bearers thereby avoiding bowing of the plate and blanket cylinders. By operating off-bearer and avoiding a bowing of the blanket and plate cylinders the operational efficiency of the press is significantly increased.
  • a method of operating a rotary machine in accordance with the present invention is to be applied to an apparatus comprising a frame having first and second support portions, an operating member mounted on the support portions for rotation, a cooperating member mounted on the support portions and disposed relative to the operating member so that printing, cutting or perforating is performed on a web of material as it passes between the operating and cooperating members and the operating member is rotated.
  • the method as it applies to an offset press comprises the steps of setting the frame supports to a predetermined temperature above the ambient, situating the bearers so that there is a selected space between them, packing the blanket cylinder "lightly" such that the radius of the blanket cylinder is slightly greater than the radius of the bearers, monitoring the space between the bearers during operation of the press, and adjusting the temperature of the frame supports to keep the distance between the bearers adequate to assure satisfactory print quality.
  • the temperature control is coordinated or synchronized with the speed of rotation of the machine by controlling the temperature in proportion to that speed of rotation.
  • FIG. 1 is a schematic diagram showing paper flow through a printing press.
  • FIG. 2 is a partially sectioned view of the printing press of FIG. 1 taken along the line 2-2 in FIG. 1 showing a printing press running without the present invention and is representative of the prior art.
  • FIG. 3. is a partially sectioned view of the printing press of FIG. 1 taken along the line 2-2 in FIG. 1 showing a printing press running with the present invention.
  • FIG. 4a-d are schematic diagrams showing the gap between bearers during operation of a press utilizing the present invention.
  • FIG. 5 is a side view of a non-bearered or Flexo press.
  • FIG. 1 shows schematically an offset printing operation wherein a web of paper 100 is passed through an offset printing press 102 which is shown as a single printing stage or station, however typically would comprise several printing stages.
  • the paper web 100 is passed from the printing press 102 through a variety of post printing equipment such as a dryer and/or chill rolls indicated generally at 104.
  • the web 100 is next fed through a rotary cutter 106 where the web 100 is intermittently severed to form sheets or pages 108, which pages may comprise one or more sheets of printed material.
  • the rotary cutter 106 may, for example, be a part of a sheeter 110 such as that illustrated in U.S. Patent No. 3,994,221.
  • the equipment for each printing stage or station includes a pair of inked plate cylinders 112, each carrying ink images of matter to be printed on the two sides of the paper web 100 and two offset or blanket cylinders 114 for transferring the ink images from the plate cylinders 112 to the paper in the desired registry.
  • the transfer surfaces on the blanket cylinders 114 are provided by sheets or blankets wrapped around the cylinders and secured thereto by suitable clamping means (not shown) disposed in transverse slots or gaps 114A extending throughout the length of the cylinders.
  • the two blanket cylinders 114 also serve as backing or impression cylinders each for the other, the moving web 100 engaging both in a common transverse contact zone so that both sides of the web are printed at the same time.
  • the two blanket cylinders 114 are phased so that the blanket joints or gaps 114A of both revolve through the common contact zone and in register with the spacing or transverse border area between successive printings or signatures.
  • Sheets or plates containing the impression to be printed onto the paper web 100 are similarly wrapped around the plate cylinders 112 and secured thereto by suitable clamping means (not shown) disposed in transverse slots or gaps 112A which similarly extend throughout the lengths of the plate cylinders 112.
  • the blanket and plate cylinders 112, 114 are phased so that the blanket joints or gaps 114A and the plate joints or gaps 112A of the blanket and plate cylinders similarly revolve through a common contact zone and in registry with the spacing or transverse border area between successive printings or signatures.
  • the impression pressure between the blanket cylinders 114 can be set in a variety of ways well known in the art, such as by adjustment screws and apparatus 116.
  • the impression pressure between the blanket cylinders 114 and the plate cylinders 112 can be set in a variety of ways well known in the art, such as by adjustment screws and brackets 118.
  • the impression pressure between the blanket cylinders and between the blanket cylinders and plate cylinders is set while the printing press is at rest.
  • FIG. 2 which is included as representative of the prior art, some of the major shortcomings of a conventional offset press running without using the present invention are shown. Because heat is generated by the bearers 112b and 114b engaging each other plate cylinder 112 bows causing bearer 112b to lift off on the inside (shown at B) and journal 115 to pull away from bearer 112b (shown at C).
  • FIG. 3 shows a partially sectioned view through the blanket and plate cylinders and the supporting sidewalls of the printing press 102 taken along line 2-2 shown in FIG. 1.
  • the blanket cylinders 114 includes bearers 114b and the plate cylinders 112 includes bearers 112b.
  • Bearers 112b and 114b are illustrated here to show fully the method of the present invention and it should be appreciated that the exact size or shape of any of the bearers is a design consideration and does not form part of the present invention.
  • the blanket cylinders 114 are shown having a smaller radius than bearer elements 114b.
  • the blanket cylinders 114 must first be packed when the machine is at rest such that the packing extends the effective radius of each blanket cylinder 114 beyond the radial length of the bearers 114b. By packing the blankets in this manner, pressure will be applied between the blanket cylinders 114 before bearers 114b come into contact. This initiates the "impression" of the press.
  • the frame supports are heated to a predetermined temperature above the ambient temperature, thus growing the effective lengths of the frame supports and consequently increasing the distance between the bearers.
  • the distance between bearers 114b is increased.
  • Bearers 114b are then mechanically positioned with a predetermined space or distance between them prior to operation of the press.
  • the space A eliminates friction caused by the bearers 114b engaging one another.
  • the space A between the bearers 114b is set by adjusting the bearings on frame supports 202, 204 in a position such that the bearers 114b which are attached to the bearings are not in contact.
  • the bearers 114b are positioned for off bearer operation while the press is at rest.
  • the press may be operated by mechanically positioning the bearers before the frame supports have been heated.
  • the blanket and plate cylinders are packed to achieve the desired impression pressure on the web of paper 100.
  • the blanket cylinders 114 and plate cylinders 112 are packed such that the radius of the cylinders is slightly greater than the radius of the connected bearers. This procedure assures a constant pressure between blanket cylinders and between plate and blanket cylinders and printing is effected on the web of paper passing between blanket cylinders 114.
  • the press is precisely adjusted during operation by controlling the temperature of the section of the frames 202 and 204 located between the bearings 200 supporting the plate and blanket cylinders.
  • these frame sections are constructed from a material having a positive co-efficient of thermal expansion since heating elements are used for the thermal control.
  • the frame dimensions can be increased or decreased by thermal expansion or contraction of those portions of the frame by an amount approximately equal to the growth of the bearers due to centrifugal force, bearer wipes and heating and other well known factors.
  • Precisely adjusting the distance between bearers 114b during high speed operation of the press is accomplished by correspondingly raising or lowering the temperature of the frame supports. Raising and lowering the temperature of the frame supports 202, 204 maintain an appropriate distance between bearers 114b, preferably the preset distance between bearers 114b simultaneously maintains the initial positioning of the blanket 114 and plate cylinders 112.
  • the portions of the framework separating the bearers which support the cylinders are controlled by thermal heating elements shown in FIG. 3 as either strip heaters 300 positioned on either side of the frame or circular heating elements 302 which are inserted into small holes drilled either partially or totally through the supporting framework.
  • the strip heaters 300 are held in place by flanges 304 or by other appropriate supports.
  • Press frames are generally constructed of steel and are of substantial rigidity and strength so that holes drilled to receive heating elements 302 should not effect the strength of the support members.
  • the positioning of the heating elements is best seen in FIG. 3 as being oriented along a line generally normal to the line interconnecting the centers of the associated cylinders which are effected by the heating elements.
  • two cylindrical heating elements 302 are positioned between the two blanket cylinders.
  • Strip heaters 300 are positioned between the blanket to plate cylinders. It is not necessary to maintain the entire frame support at the temperatures required to "grow" the frame. The temperature of the portions of the frame centered between any two cylinders can be adequately controlled to produce the dimensional changes required to compensate for the centrifugal and heat growth produced by high speed operation of the printing press. It should be understood that the gap between any two cylinders or bearers can be monitored and adjusted separately or all gaps may be monitored simultaneously.
  • Fig. 4a shows a gap 501 between plate cylinder bearer 112b and packing cylinder bearer 114b when the bearers are initially positioned prior to operation.
  • a larger gap 502 is created between plate cylinder bearer 112b and blanket cylinder bearer as shown in Fig. 4b.
  • the gap 502 is adjusted to a predetermined distance by varying the temperature or making standard mechanical adjustments.
  • Fig. 4d shows plate cylinder bearer 112b and blanket cylinder bearer 114b again with gap 501 between them due to an increase in the heat supplied to frame supports 202 and 204 to compensate for the centrifugal force acting on the cylinders and bearers, thus maintaining a desired gap between bearers for optimal printing efficiency.
  • Fig. 4a-4d are exaggerated to show the effect the present invention has on a conventional offset press. It should be understood that in operation the speed of rotation is constantly monitored or the gap is visually or through other means constantly monitored and the heat supplied to grow frame supports 202 and 204 is adjusted correspondingly, thus the gap between the plate cylinder bearer and blanket cylinder bearer, and the gap between the blanket cylinder bearers is maintained at substantially constant.
  • Fig. 5 shows a typical Flexo printing unit. Paper web 400 is fed between impression cylinder 405 and plate cylinder 410. Plate cylinder 410 receives ink when cooperating with the grooved or annolux roll 415. Simultaneously, plate cylinder 410 cooperates with impression cylinder 405 transferring the designated configuration to paper web 400 as it passes between impression cylinder 405 and plate cylinder 410.
  • the method, as applied to this bearerless type printing press would include setting the frame supports to an initial temperature above the ambient, effectively lengthening the frame supports and consequently increasing the distance between impression cylinder 405 and plate cylinder 410, (indicated as 401 in Fig. 5) and plate cylinder 410 and annolux cylinder 415 respectively (indicated as 402 in Fig. 5).
  • the position of the impression cylinder relative to the plate cylinder, and the portion of the plate cylinder relative to the annolux cylinder would then be set prior to operating the press. While the machine is operating the original position of the operating cylinders is maintained in the same manner as the offset bearered press. Thus the initial optimum setting of the operating cylinders is approximately maintained thereby maintaining the print quality during the entire time of operating the machine, and at all speeds of operating the press.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Rotary Presses (AREA)
EP91114491A 1990-11-28 1991-08-29 Méthode de réglage thermique pour contrôler l'impression d'une presse à imprimer Withdrawn EP0487836A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US61913490A 1990-11-28 1990-11-28
US619134 2003-07-15

Publications (1)

Publication Number Publication Date
EP0487836A1 true EP0487836A1 (fr) 1992-06-03

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EP91114491A Withdrawn EP0487836A1 (fr) 1990-11-28 1991-08-29 Méthode de réglage thermique pour contrôler l'impression d'une presse à imprimer

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EP (1) EP0487836A1 (fr)
CA (1) CA2043297A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10228242B4 (de) * 2002-06-25 2004-09-16 Koenig & Bauer Ag Druckwerk einer im wasserlosen Offsetdruck arbeitenden Rotationsdruckmaschine mit zwei Druckstellen
CN110126443A (zh) * 2019-06-23 2019-08-16 黎兴才 一种凸版印刷机

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4426897A (en) * 1981-07-13 1984-01-24 Littleton Francis J Thermal adjustment method and apparatus for rotating machines

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4426897A (en) * 1981-07-13 1984-01-24 Littleton Francis J Thermal adjustment method and apparatus for rotating machines

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10228242B4 (de) * 2002-06-25 2004-09-16 Koenig & Bauer Ag Druckwerk einer im wasserlosen Offsetdruck arbeitenden Rotationsdruckmaschine mit zwei Druckstellen
US7392742B2 (en) 2002-06-25 2008-07-01 Koenig & Bauer Aktiengesellschaft Devices for supporting and adjusting a form cylinder in a printing group of a rotary printing press
CN110126443A (zh) * 2019-06-23 2019-08-16 黎兴才 一种凸版印刷机

Also Published As

Publication number Publication date
CA2043297A1 (fr) 1992-05-29

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