ne Pr

anical Phases-Speed-Pressure-Levelling the

ther's, and such would be the natural trend of a discussion on these lines. The machines all have, it is true, many points in common where comparisons would be legitimate and easy. Yet, on the other hand, they each possess distinct advantages which will no doub

13) gives a fair general idea of

ght between the small cylinder and the stone, when pressure is immediately applied. The stone is simply blocked up in the bed of the machine and the position of the print on the pap

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e primary purpose of the machine itself was undoubtedly to accelerate the reproductive power of lithography from a commercial point of view; and throughout the entire course of its development the aim of the engineer has been to produce a printing machine with an ever-increasing capacity for reproduction. It does not follow, however, that the printer's respon

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ated with machine printing, but which offers little that is new to the practical wor

impression which is defective owing to some error of judgment in its preparation. It undoubtedly secures the desired effect, but at what a cost! There is a proportionately heavier drag on the machine and a greater strain on its most vital parts. The following view of this matter may be regarded as somewhat exaggerated, but it is by no means an uncommon state of affairs, and will at least serve to emphasise the importance of this point. It is a popular fallacy to suppose that in adjusting the litho-stone to the bed of the printing machine it should be made perfectly level. As a matter of fact a much easier and more satisfactory impression can be made from a stone which is worked just a little higher at the front or gripper edge than at the back, and for this reason. The drag on the cylinder as it makes the impression is appreciably greater at the back

e stone would almost certainly cause an appreciable indentation in the cylinder covering. This would

graphic stone in the machine for the adjustment

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movement of the screws will therefore cause a corresponding movement of the stone carriage on t

at the points required. The intermittent movement referred to is obviated in various ways. Fig. 13 shows an example of one which is both simple and effective. It might be well also to explain the principle and purpose of the cylinder brake. It is almost impossible to cut mechanical gearing which will run easily and yet be entirely free from slogger. Conse

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of power and its economical application. It is but reasonable to suppose that the power required to move a set of rollers arranged in th

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inish. Every printer knows something of the effect produced by excess of water upon printing inks. It hardens and stiffens them by accelerating oxidisation. In course of time their free working on the rol

onstant and careful attention; any arrangements for this purpose should therefore be as effective as possible. The damping rollers

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t collects any accumulation of ink or scum from the actual dampers, and can be cleaned at any time without serious interference with the progr