US3785285A - Damping device for rotary offset press - Google Patents

Damping device for rotary offset press Download PDF

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Publication number
US3785285A
US3785285A US00161545A US3785285DA US3785285A US 3785285 A US3785285 A US 3785285A US 00161545 A US00161545 A US 00161545A US 3785285D A US3785285D A US 3785285DA US 3785285 A US3785285 A US 3785285A
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US
United States
Prior art keywords
roll
wiping
transfer roll
transfer
rotating
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.)
Expired - Lifetime
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US00161545A
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English (en)
Inventor
L Chambon
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.)
Societe dEtudes de Machines Speciales SA
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Societe dEtudes de Machines Speciales SA
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Filing date
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Publication of US3785285A publication Critical patent/US3785285A/en
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Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41F—PRINTING MACHINES OR PRESSES
    • B41F7/00—Rotary lithographic machines
    • B41F7/20—Details
    • B41F7/24—Damping devices
    • B41F7/26—Damping devices using transfer rollers

Definitions

  • a wiping r011 having a flexible surface is pressed against the transfer roll.
  • the wiping roll is rotated very slowly at a speed between one hundreth to one tenth of the speed of the transfer roll, the sludge entrained by the wiping roll being collected by a scraper blade or other means so as to prevent it being recycled.
  • this type of device has the disadvantage that the ink and dampening medium which come into contact on the forme roller emulsify and form a sludge which is constantly recycled through the damping and inking systems so that poor prints are eventually produced.
  • a damping device comprises a transfer roll with a hard, hydrophilic surface, the lower part of which is immersed in a trough containing a damping medium.
  • the transfer roll is rotated at a constant but controllable speed in contact with a forme roll, and has pressed against it a wiping roll with a flexible peripheral layer.
  • the wiping roll is driven in the opposite direction to the transfer roll but at a very slow speed of between one hundredth and one tenth of the rotational speed of the transfer roll.
  • the speed at which the wiping roll is driven is so low that the roll is practically stationary with the result that the sludge is prevented from returning to the inking system. Nevertheless, the rotation of the wiping roll is such that the quantity of sludge which does accumulate on the inlet side of the zone of contact between the transfer and wiping roll is passed gradually through the said zone and forms a thin film on the surface of the wiping roll down stream of the zone. This film can easily be removed either by wiping the surface with a cloth by hand or by some means of an automatic scraper in contact with the said surface.
  • FIG. 1 is a schematic vertical section through a dampening device of an offset rotary printing machine
  • FIG. 2 is a sectional diagram, on a larger scale, of the contact zone between the transfer roll and the wiping roll.
  • the dampening device shown in FIG. 1 comprises a trough 1 containing a quantity of dampening medium for example water, which is kept to a fixed level and constantly recirculated by a filtration device, such as a pump, which is not shown in the drawing.
  • a dampening or transfer roll 2 of which the lower part is immersed in the dampening medium contained in the trough l, is integral or fast with a horizontalshaft 3. This shaft 3 and consequently the transfer roll 2 are rotated in an anti-clockwise direction as viewed in the drawing and at a constant but adjustable speed,by a variable-speed electric motor 4, via a gear train 5.
  • the peripheral surface of the dampening roll 2 has a comparatively hard covering with considerable affinity for water, the covering being made for example of chromium.
  • a wiping roll 6 is mounted so that its peripheral surface contacts that of the roll 2 in a zone 7 situated substantially in a horizontal plane passing through the axis of the shaft 3.
  • the wiping roll 6 comprises a central core 6a, of a relatively hard material, for example steel, and a surface layer 6b of a supple material such as rubber.
  • the wiping roll 6 is firmly pressed against the transfer roll 2, sufficiently to ensure that the surface layer 6b is considerably compressed in the contact zone 7.
  • the transfer roll 2 is also pressed at a position substantially diametrically opposite the zone of contact 7 with roll 6, against a roll 8 having a supple peripheral layer and rotating at a constant speed, in a clockwise direction.
  • this roll 8 can consist either of the forme roll rotating on the plate or on the etched roll 9 of the printing machine, as shown in FIG. 1, or of a distributor roll.
  • the forme roll 8 itself is in contact, in its upper part, with an inking roll 1 l which rotates in the anti-clockwise direction and has its periphery regularly fed with ink by an inking device of a known type and not shown in the drawing.
  • the roll 8 is freely mounted and is controlled by the rolls 9 and 11.
  • the transfer roll 2 which carries on its periphery an even, thin film of water a, partly deposits this film on the surface of the form roll 8, which has previously been inked by the inking roll 11.
  • the layer of water distributes itself in more or less equal proportions between the rolls 2 and 8, downstream of their contact zone.
  • the forme roll 8 in its turn, deposits the mixed layer of ink and water, present on its surface, onto the plate or the etched roll 9 of the printing machine. Owing to the layering effect occurring in the zone of contact under pressure between the roll 8 and the plate or the engraved roll 9, an emulsion of water in the ink is formed and continues to adhere to the surface of the rubber layer of the forme roll 8, downstream of its zone of contact with the engraved roll 9.
  • This emulsion is carried along by the forrne roll 8 as far as the zone of contact between this roll and the transfer roll 2, whereafter some of it is transferred to the transfer roll 2 while the remainder is once again conveyed to the plate or etched roll 9.
  • the quantity of emulsion adhering to the roll 2 is thus passed through the body of water contained in the trough 1. Some of the emulsion is washed off the roll 2 and is filtered out during recirculation while the remainder continues to adhere to the surface of the roll 2 and is thus conveyed towards the contact zone 7 between the roll 2 and the wiping roll 6.
  • the wiping roll is kept stationary, the emulsion conveyed into the contact zone 7 by the roll 2, accumulates between this roll and the wiping roll 6, thus forming a mass of sludge indicated at e in FIGS. 1 and 2.
  • the invention provides for the wiping roll 6 to be rotated at a very low speed in comparison with that of the roll 2.
  • the shaft 12 of the wiping roll 6 is driven by the electric motor 4, via a train of reduction gears marked as a whole by the reference number 13.
  • the speed reduction selected for the gear tain 13 is such that the rotation speed of the wiping roll 6 is between one hundredth and one tenth of that of the roll 2.
  • the wiping roll 6 is rotated in the opposite direction to the roll 2, i.e., clockwise in the case of FIGS. 1 and 2.
  • the froth formed by the emulsion of water and ink is caused to move in a layer or film during its passage in the contact zone 7 between the rolls 2 and 6, and the sludge which results from the layering of this froth and which is indicated by e, in FIG. 2 continues to adhere to the surface of the wiping roll 6, down stream ofthe contact zone 7.
  • the sludge resulting from the emulsion can be collected by a doctor blade 14 in contact with the upper portion of the peripheral surface of the wiping roll 6 or alternatively by wiping over the surface of this roll with a cloth held in the hand. This ensures the efficient operation of the dampening device, owing to the fact that the sludge caused by the emulsion of the water in the ink is eliminated without difficulty.
  • a rotary press of the offset type having a rotating inking roll, a trough for a dampening liquid, a rotating transfer roll having a hydrophilic surface, part of said surface being disposed in said trough to pick up said dampening liquid from said trough as the transfer roll rotates, a third roll with a flexible peripheral layer in rolling contact with said inking roll and said transfer roll, and a wiping roll having a flexible peripheral layer pressed firmly against the transfer roll so as to compress said flexible peripheral layer of the wiping roll in the zone of contact with the transfer roll, means for rotating said transfer roll in a direction to engage said wiping roll after picking up dampening liquid from said trough and before engaging said third roll, the improvement comprising means for maintaining said wiping roll almost stationary so as to collect on the inlet side of the zoneof contact between the transfer roll and the wiping roll any sludge comprising an ink-dampening liquid emulsion formed on the transfer roll while rotating said wiping roll in a direction opposite to the transfer roll at
  • said means for rotating the transfer roll and said means for rotating the wiping roll comprise a single electric motor, a first gear train by means of which the transfer roll is driven by the said motor in a selected first direction, and a second reduction gear train by which the wiping roll is driven from the said motor in a second direction opposite to the aforementioned first direction of rotation, and at a speed of between one hundredth and one tenth of the speed of rotation of the transfer roll.
  • said cleaning means including a scraper contacting the peripheral surface of the wiping roll.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Inking, Control Or Cleaning Of Printing Machines (AREA)
  • Rotary Presses (AREA)
US00161545A 1970-07-10 1971-07-12 Damping device for rotary offset press Expired - Lifetime US3785285A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR7025901A FR2097585A5 (enrdf_load_stackoverflow) 1970-07-10 1970-07-10

Publications (1)

Publication Number Publication Date
US3785285A true US3785285A (en) 1974-01-15

Family

ID=9058654

Family Applications (1)

Application Number Title Priority Date Filing Date
US00161545A Expired - Lifetime US3785285A (en) 1970-07-10 1971-07-12 Damping device for rotary offset press

Country Status (5)

Country Link
US (1) US3785285A (enrdf_load_stackoverflow)
DE (1) DE2134064A1 (enrdf_load_stackoverflow)
FR (1) FR2097585A5 (enrdf_load_stackoverflow)
GB (1) GB1347508A (enrdf_load_stackoverflow)
NL (1) NL142620B (enrdf_load_stackoverflow)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4000691A (en) * 1973-02-28 1977-01-04 Maschinenfabrik Augsburg-Nurnberg Ag Rotary printing press with improved inking system
US4066017A (en) * 1975-07-09 1978-01-03 Addressograph-Multigraph Corporation Blanket cleaner for duplicating machines
WO1979000245A1 (en) * 1977-10-29 1979-05-03 Bp Chem Int Ltd Foundry compositions containing propylene glycol monoacetate
WO1979001110A1 (en) * 1978-04-18 1979-12-13 H Dahlgren Newspaper printing system
WO1980000144A1 (en) * 1978-04-18 1980-02-07 H Dahlgren Reversible newspaper press
US4237785A (en) * 1978-04-18 1980-12-09 Dahlgren Harold P Inker for applying newsprint type ink
US4488485A (en) * 1982-06-03 1984-12-18 Koenig & Bauer Aktiengesellschaft Simplified inking unit
US5438921A (en) * 1993-08-24 1995-08-08 Riso Kagaku Corporation Stencil printing device having an ink mixing unit
US5599266A (en) * 1994-06-21 1997-02-04 American Roller Company Foam reservoir fluid transfer roller

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0022191A1 (de) * 1979-07-05 1981-01-14 Automation für grafische Technik A.G. Druckmaschine, insbesondere Offset-Druckmaschine
GB2151186B (en) * 1983-12-12 1987-09-09 Baldwin Technology Corp Dampening system
DE3923350C1 (enrdf_load_stackoverflow) * 1989-07-14 1990-05-17 Man Roland Druckmaschinen Ag, 6050 Offenbach, De

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3026795A (en) * 1957-01-18 1962-03-27 Maschf Augsburg Nuernberg Ag Dampening apparatus for rotary printing presses
US3038405A (en) * 1959-12-04 1962-06-12 Harris Intertype Corp Lithographic dampening device and method
US3285169A (en) * 1965-05-28 1966-11-15 Hans H Hartwig Apparatus and method for flexographic printing with doctor roll ink control
US3343484A (en) * 1964-12-16 1967-09-26 Harold P Dahlgren Lithographic dampener with skewed metering roller
US3587460A (en) * 1967-05-22 1971-06-28 Etudes De Machines Speciales Dampening system for rotary offset press

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3026795A (en) * 1957-01-18 1962-03-27 Maschf Augsburg Nuernberg Ag Dampening apparatus for rotary printing presses
US3038405A (en) * 1959-12-04 1962-06-12 Harris Intertype Corp Lithographic dampening device and method
US3343484A (en) * 1964-12-16 1967-09-26 Harold P Dahlgren Lithographic dampener with skewed metering roller
US3285169A (en) * 1965-05-28 1966-11-15 Hans H Hartwig Apparatus and method for flexographic printing with doctor roll ink control
US3587460A (en) * 1967-05-22 1971-06-28 Etudes De Machines Speciales Dampening system for rotary offset press

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4000691A (en) * 1973-02-28 1977-01-04 Maschinenfabrik Augsburg-Nurnberg Ag Rotary printing press with improved inking system
US4066017A (en) * 1975-07-09 1978-01-03 Addressograph-Multigraph Corporation Blanket cleaner for duplicating machines
WO1979000245A1 (en) * 1977-10-29 1979-05-03 Bp Chem Int Ltd Foundry compositions containing propylene glycol monoacetate
WO1979001110A1 (en) * 1978-04-18 1979-12-13 H Dahlgren Newspaper printing system
WO1980000144A1 (en) * 1978-04-18 1980-02-07 H Dahlgren Reversible newspaper press
US4208963A (en) * 1978-04-18 1980-06-24 Dahlgren Manufacturing Company Newspaper printing system
US4237785A (en) * 1978-04-18 1980-12-09 Dahlgren Harold P Inker for applying newsprint type ink
US4488485A (en) * 1982-06-03 1984-12-18 Koenig & Bauer Aktiengesellschaft Simplified inking unit
US5438921A (en) * 1993-08-24 1995-08-08 Riso Kagaku Corporation Stencil printing device having an ink mixing unit
US5599266A (en) * 1994-06-21 1997-02-04 American Roller Company Foam reservoir fluid transfer roller

Also Published As

Publication number Publication date
NL7109063A (enrdf_load_stackoverflow) 1972-01-12
FR2097585A5 (enrdf_load_stackoverflow) 1972-03-03
DE2134064A1 (de) 1972-01-20
GB1347508A (en) 1974-02-27
NL142620B (nl) 1974-07-15

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