Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41N—PRINTING PLATES OR FOILS; MATERIALS FOR SURFACES USED IN PRINTING MACHINES FOR PRINTING, INKING, DAMPING, OR THE LIKE; PREPARING SUCH SURFACES FOR USE AND CONSERVING THEM
  • B41N1/00—Printing plates or foils; Materials therefor
  • B41N1/04—Printing plates or foils; Materials therefor metallic
  • B41N1/08—Printing plates or foils; Materials therefor metallic for lithographic printing
  • B41N1/083—Printing plates or foils; Materials therefor metallic for lithographic printing made of aluminium or aluminium alloys or having such surface layers
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C21/00—Alloys based on aluminium
  • C22C21/02—Alloys based on aluminium with silicon as the next major constituent
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C21/00—Alloys based on aluminium
  • C22C21/06—Alloys based on aluminium with magnesium as the next major constituent
  • C22C21/08—Alloys based on aluminium with magnesium as the next major constituent with silicon

Definitions

• the present invention relates to an aluminum printing plate, and more particularly, the present invention is con: cerned with an offset printing plate formed of a certain aluminum alloy, and with a method of printing utilizing such printing plates.
• the printing plate of the present invention is particularly suitable for multicolor offset printing.
• an offset printing plate may be subjected to a high degree of stretching and possesses little resiliency or tendency to return after stretching to its previous dimension-s, particularly for multicolor offset printing, since the pl'ates'are subjected to stretching in order to adjust dimensional differences between the plates and the paper which is to be imprinted.
• the present invention contemplates an offset printing plate formed of an aluminum alloy consisting of between 0.7% and 1.3% magnesium, bet-ween 0.7% and 1.3% silicon, between 0.4% and 1.0% manganese, up to 0.1% copper, the balance being aluminum.
• the present invention also encompasses in an offset printing process the step of forming a transferable image on an aluminum alloy plate having the following composition: between 0.7% and 1.3% magnesium, between 0.7% and 1.3% silicon, between 0.4% and 1.0% manganese, up to 0.1% copper, the balance being aluminum.
• a plate carrying an image for offset reproduction and formed of an aluminum alloy of the composition described below will possess the desired qualities i.e., can be subjected to a very high degree of stretching, and will have a relatively low yield point or elastic limit.
• Such plate according to the present invention consists of an aluminum alloy containing between 0.7% and 1.3% magnesium, be-
• the magnesium content of alloy will be about 1%, the silicon content about 1% and the manganese content about 0.8%.
• Offset printing plates produced of such alloy are excellently suitable, particularly for multicolor printing. It hasybeen found that plates of the above described alloy compositions can be made in reproducible quality, particularly with respect to stability and shape retention.
• the plates possess very little resiliency and this is of decisive importance in offset printing in order to obtain proper registry and accurate contours. It is particularly surprising that plates of the above described alloy possess such high extensibility and at the same time very great dimensional stability. Usually, these two qualities are not found to such a high degree in one and the same aluminum alloy.
• a square plate of 1,000 x 1,000 X 0.5 mm. formed of the above described alloy, namely an aluminum alloy containing about 1% magnesium, 1% silicon and 0.8% manganese, and weighing 1.35 kg. is stretched by between about 3 and 5 mm. along its length and width, so that these dimensions are extended by about 0.3 to 0.5%.
• This degree of stretching corresponds to the normal requirement of offset printing, or particularly multicolor offset printing.
• the thus stretched plate retains its stretched shape, and no resilient return towards the original unstretched shape and dimensions of the plate could be observed.
• the printing plates are worked up at the print shop in various manners.
• a pie-treatment is carried out which comprises etching, galvanizing or anodizing of the plate.
• etching e.g., when an oxide layer is formed on the plate by anodizing, it is very important that the anodically oxidized surface is free of tear lines.
• This requirement can be met to a particularly high degree in connection with plates formed of the above-described alloy by coating preferably both faces of the plate with a pure aluminum layer, consisting of aluminum which preferably will possess a purity of between 99.5 and 99.8%.
• the thickness of each of the plating layers should be kept at between 2% and 15% of the thickness of the aluminum alloy plate and preferably at about 8% of such thickness.
• the aluminum which forms the balance of the ,above described alloy may contain conventional impurities including, for instance, 0.1% or up to 0.3% zinc.
• the iron content of the alloy may be up to 0.5%, however the iron content varies greatly depending on the quality of the aluminum such as virgin aluminum which may be used for forming the alloy of which the plate of the present invention is produced.
• virgin aluminum usually has a purity of about 99% and, for instance, the virgin aluminum which is known under the trade name Erftal contains only a relatively low iron content of about 0.040%.
• the plated layers of pure aluminum are generally applied in conventional manner by rolling.
• a offset printing plate carrying an ink receptive image adapted to be reproduced by offset printing, said offset printing plate consisting of an aluminum alloy in soft condition and composed of between about 0.7% and 1.3% magnesium, between about 0.7% and 1.3% silicon, between about 0.4% and 1.0% manganese, up to about 0.1% copper, the balance being aluminum, said offset printing plate being stretchable and substantially retaining after stretching its stretched shape.
• An offset printing plate carrying an ink receptive image adapted to be reproduced by offset printing, said offset printing plate comprising an aluminum alloy plate having opposite faces and consisting of an aluminum alloy in soft condition composed of between about 0.7% and 1.3% magnesium, between about 0.7% and 1.3% silicon, between about 0.4% and 1.0% manganese, up to about 0.1% copper, the balance being aluminum; and a layer consisting of substantially pure aluminum and having a thickness equal to between about 2% and 15% of the predetermined thickness of said aluminum alloy plate covering and firmly adhering to at least one of said opposite faces of said aluminum alloy plate.
• An offset printing plate carrying an ink receptive image adapted to be reproduced by offset printing, said offset printing plate comprising an aluminum alloy plate having opposite faces and consisting of an aluminum alloy in soft condition composed of between about 0.7% and 1.3% magnesium, between about 0.7% and 1.3% silicon, between about 0.4% and 1.0% manganese, up to about 0.1% copper, the balance being aluminum; and two layers of substantially pure aluminum covering and firmly adhering to said opposite faces respectively of said aluminum alloy plate.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Printing Plates And Materials Therefor (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

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Family Applications (1)

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Cited By (2)

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Citations (4)

• 1963
  • 1963-07-19 DE DEV24333A patent/DE1206596B/de active Pending
• 1964
  • 1964-05-29 CH CH703364A patent/CH445530A/de unknown
  • 1964-06-22 GB GB25770/64A patent/GB1061164A/en not_active Expired
  • 1964-06-24 AT AT542064A patent/AT250037B/de active
  • 1964-07-07 US US380916A patent/US3250215A/en not_active Expired - Lifetime

Patent Citations (4)

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