DE1962363A1 - Film dampening unit for offset printing machines - Google Patents

Description

KOENIG & BAUER AG VUrzburg, December 9, 196?

Würzburg - 326 / ¥ «/» c

P a t η t η m 1 d u η g Film dampening unit for offset printing machines

The invention relates to a film dampening system for offset printing machines consisting of a Vasserduktor with textile cover, a film roller, a dampening roller and a Vaeserkasten

A design feature of all the dampening systems on the market is that the Vaaaerductor is in the Immerse the surface of the Feuohtwasser and let the water over the entire width of the Vasserduktor * in uncontrolled Catfish in relation to the Vaßserfilmdioke for transmission · »share guide between water ductor and film roller *

The water ductors have different types of surface coatings such as smooth chrome plating with or without textile cover,

The water filii at the Vasserduktor becomes at slow speed adjusted so that it corresponds to the idea guidance, so generated when the speed changes with mechanical (synchron with the Masohine) powered dampening units the changing ratio between return speed and Dragging the Vaasers a rule characteristic,

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at the slower machine speed, there was less water is conveyed ala at high machine speed

Da a Feuchtwassar, daa from the Waaserduktor during its rotation is dragged along, runs on the surface of the water duct back to the water tank · Turn slowly large proportion of the adhering .water back · at faster Rotation is not enough time to reverse, so that a Occasionally larger amounts are taken along and transferred.

So if a mechanically (ayn or ο η with the machine) driven The dampening system is regulated in the water supply at low speed, and overhumidification occurs when the speed is increased Something like that, the peripheral speed is necessary to slow down the Wassarduktora. So here is «in · not linearly proportional Record water delivery at the conventional dampening units. .

In the linguistic usage of the professional world, this led to the fact that "less water ^{11 is} needed at high wind speeds," more water * at slow speeds, and this phenomenon is interpreted as meaning that less water can evaporate at high machine speed than at slow speed. for the non-linearly proportional supply of water actually arises, as has already been said, from the fact that when the turning speed of the MaaChina increases, as a result of the increasing towing speed, the thickness of the water filsia bunipat. Hence it is necessary to use the

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To slow down the circumferential speed of the water duct again the water film thickness corresponding to the ideal moisture content to reach on the Waeserduktor.

The relationships described above resulted in conventional Dampening units to the fact that the dampening ductor drives from the mechanical The drive part of the machines is separate and provided with separate, manually adjustable electric motor drives "

became. With the help of the electric motor drive it is possible to regulate the water ductor speed at the respective machine speeds so that the required thickness of the Moist film is generated. In practice, the procedure is such that the machine is brought up to operating speed. Only after A balance between paint and water is established when the operating speed is reached.

Proves in such systems to be disadvantageous, such as loading A ride said that at speed changes of the engine immediately after an over- or ünterfeuchtung. This non-linear proportional Yasser delivery creates a lot of waste. To avoid this, the drive of the water duct must be readjusted by hand when the speed of the machine changes.

Recently, high-performance machines have been controlled electronically Electric drives used for the water ductors that should roughly compensate for the faulty delivery curve of a water duct dipping into the water in an uncontrolled manner. Such

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Drives are very complex

To add the fountain solution to specific points on the printing form keep away «is known from wipers on the dampening system in the form of roughly zone-wide metal lamellae, rubber squeegee rollers and air nozzles, with the help of which the Vaeser film is wiped off the surface of the water duct and thereby attached The water supply is interrupted at certain points on the printing form.

The disadvantage of interruptions in the supply of water is that the dampening system is heavily contaminated by paint in these places.

Another problem lies in the water circulation within the dampening system, the fresh water is transferred from the water duct the transfer cylinder to the dampening form roller and from there brought to the printing form. The film of water used on the printing form depends on the ink coverage of the printing form The printing plate material, the quality of the paper and the low level of evaporation They increase as a result of machine heating.

However, it is always on the printing form after the dampening water has been applied a water return stream to the water duct is available.

In this water return flow are pigments dissolved from the moist water, Oils, varnishes and resins, paper dust contaminants and acidic or basic fountain solution washes off the paper work back on the forme cylinder «included.

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December 9, 1969

These return flow impurities lead to certain machine running times to stronger disturbances within the dampening system, whereby it is inevitable that these disturbances by Vaschen to eliminate. However, this creates obstacles to production Machine downtimes With high-speed machines, such malfunctions occur very quickly one after the other.

The subject; the invention is based on the object a To create a dampening system that delivers a dampening water quantity that is linearly proportional to the speed of the machine, i.e. at any machine speed is per forme cylinder primary rotation Constantly brought the same amount of Vaeser to the printing form and consumed there. This linear proportional promotion of the water has its analogy in the linear proportional Promote color. It is also part of the task to dissolve it in the water Color components, paper dust and water that is disturbed in the pH-Vert are away from the water duct and the actual fountain solution » to keep. ·

The object is achieved according to the invention in that the Vasserduktor mechanically via a reduction gear accordingly the machine speed from a drive shaft of the machine is drivable, the Vaeserduktordrehzahl with the help of a mechanical, continuously variable control gear is adjustable, the excess Vasserflim on the surface d®a with a textile Covered Vasserduktors with the help of a squeegee over the ("including" Vasserduktorbreite is stripped, and on the

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The backflow side of the film roller is a wiping off the backflow water Backed squeegee arranged with a drip pan is.

This precisely dosed amount of water is brought to the transfer point between the water duct and the film roller and there, depending on the transfer setting, is transferred in an extremely uniform ψ transfer thickness.

The return flow of the dampening water from the dampening form roller the Waaserduktor becomes on the film roll with the help of a backflow doctor blade stripped and diverted separately.

With the dampening system according to the invention, it is possible to use the machine to drive at any desired speed without having to readjust the dampening solution. Ss is single

»This is necessary when setting up the machine for the first time with help of the continuously variable control gear, the amount of fountain solution at pull-in speed to adapt the ideal humidity of the printing form.

Even longer running times have to be regulated slightly, because as a result of the machine warming there is a slight increase in water depletion in the printing forme. The dampening system is - insensitive to the protruding gjes © h ± X «i © rt®B Sto" rutsgs® £ f © kte at Br @ h ^ ahlveräi3derung «n · outside xrlrd © ira Y®waäkmm.tm®n of the Feuofetwerk ® * usd of the F © uohtwaseE © rg s®wi® ®lsä © pH »value ·» Disturbance of the Feuohtwasssrs by the backflow water

avoided · «. 109.825 / 1072

'■ ■ ■ , / 7

9.12 »1969

An embodiment is shown in the drawing and is explained in more detail below.

It shows a schematic front view of the dampening system «

A water ductor 1 is driven by a drive shaft of the machine via a reduction gear (not shown), the gear ratios of which can be adjusted within certain limits by an upstream mechanical continuously variable control gear (also not shown) Vase box k is fed and its filling is kept at a constant level by an overflow pipe (not shown) «

The water duct 1 has a textile cover. The excess water film on the water duct 1 is removed by (j a squeegee 5 stripped off · This squeegee extends over the entire width of the water duct 1 and can be used in a similar way to the knives for inking units through adjacent zone screws 6 and thereby adjusted to the water duct. The drive of the water duct 1 can not by a drawn electromagnetic clutch can be interrupted at will «

The film roll 7 iet in contact with the water ductor 1, wherein

the size of the touch, the type of textile water duct, and the degree of saturation of the textile water duct cover

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after the doctor blade, the amount dee passed on to the film roller 7 Fountain solution determined. The film roll 7 becomes mechanical via a gear from the axis of the forme cylinder 10 at machine speed driven. The dampening form roller is driven by friction from both the film roller 7 and the forme cylinder 10 »

The dampening form roller 8 has a rubber pad and can be provided with a textile cover. On the backflow side of the film roll 7 there is a backflow doctor blade 9, which strips off the backflow consisting of soiled, mixed with color and pH-modified dampening water and diverts it into the collecting pan 11. In this way, impurities are removed from the surface of the film roller and cannot get into the contact area between the film wake 7 and the water ductor 1. In this way, the impurities that interfere with the operation of the machine are kept away from the water duct and dampening water box area.

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Claims (1)

12/9/1969 Claim Film dampening unit for offset printing machines consisting of one Water ductor with a textile cover, a film roller, a Dampening form roller and a water box, characterized in, that the Waseerduktor (1) mechanically via a reduction gear can be driven by a drive shaft of the machine in accordance with the machine speed, the water duct speed with the help of a mechanical, continuously variable control gear is adjustable, the excess water film on the surface of the water duct with a textile cover (i) with the help of a squeegee (5) over the entire width of the water duct is stripped, and on the backflow side of the film roll (7) with a back tr omrakel (9) wiping the back water a collecting trough (11) is arranged. 109825/1072 Blank page