GB2164295A - Damping in a multi-color lithographic proofing machine - Google Patents

Abstract

A multi-colour lithographic proofing machine comprises frame 46 and reciprocating holder 48, the frame supporting a damping water supply 66, a plurality of printing tables 41-44, a corresponding number of ink feeders 81-84, and a water distribution plate 68, whilst the holder carries one or more blanket cylinders 50, sets of inking rollers 71-74, and at least one damping roller 61-64 associated with each set, the individual rollers being tripped in the appropriate sequence for printing each of the colours during reciprocation of the holder, Figure 2. Uniform water supply for each colour can thus be obtained without any increase in size, or the reciprocating stroke, of the holder. <IMAGE>

Description

SPECIFICATION A damping water supplier in a multi-color lithographic proofing machine Background of the invention The present invention relates to a lithographic proofing machine, particularly to a damping water supplier of a multi-color lithographic proofing machine which proof-processes more than two colors at a process.

Prior art As one of the conventional multi-color lithographic proofing machines there is a multi-color lithographic proofing machine which has been disclosed in the Japanese Patent Laid-Open Publication No. 54-150203 of which schematic construction is shown in Fig. 3 of the present application.

That is, it comprises a first color table (12), a second color table (14), a third table (16) for a paper, and a frame (18) which arranges the first table (12), the second table (14) and the third table (16), has a holder (20) on the upper surface thereof and moves the holder (10) reciprocally along itself.

On the holder (20) a first color blanket cylinder (22), a second color blanket cylinder (24), a common damping roller (wetty roller) (26) for a first and a second colors, a first color ink roller (28) and a second color ink roller (30) are pivotally sLpported, and they are rolled on a predetermired table in synchronism with the movement of the holder (20).

When the holder (20) reaches at the stroke end terminal of the left side thereof, a damping means (32) comes to be disposed oppositely with the damping roller (26) at the left end portion of the frame (18), and at the right end portion of the frame (18), when the holder (20) reaches at the stroke end terminal thereof, a first color ink feeding means (34) and a second color ink means (36) are disposed oppositely with two sets of the ink rollers (28) and (30).

The reference number (38) indicates a plate for distributing water uniformly is covered with a material of good water retention characteristics, such as molten etc., for the purpose of unifying the amount of water contained in the damping roller (26).

To carry out two colors proofing printing by the apparatus shown in Fig. 3, a first color plate is mounted on the first color table (12), a second color plate is mounted on the second color table (14), and a printing paper is mounted on the third table, same as the afore-mentioned, thus, they are moved reciprocally according to the movement of the holder (20).

Then, at the both ends of the reciprocal stroke of the holder (20), from the damping means (32) damping water is fed to the damping roller (26), to the first and second color ink rollers (28) and (30) the first and the second color inks are fed from the first and the second ink feeding means (34) and (36), respectively. The damping water is fed to both the first and the second color printing plates, and the first color and the second color inks are fed and applied respectively to each of the corresponding printing plates.

The inks on the faces of the first and the second color printing plates are further transferred on the surfaces of the first ancl the second blanket cylinders (22) and (24), and printed on the surface of the printing paper apple onto the third table (16).

The multi-color lithographic proofing machine of the above described construction can carry out two color proof printing by one process, so that it is possible to improve productivity and for that reason it has been widely orevailing. In addition the multi-color lithographic proofing machine of the above described construction, comprises four sets of tables, ink rollers, blanket cylinders etc., so that proof printing of four colors may be performed by one process.

In the multi-color lithographic proofing machine, for example, in the case of carrying out proof printing of four colors, damping water is fed to the four sheets of printing plates applied on each of the tables by the respective damping rollers to which the damping water is supplied from the damping means, but there is a disadvantage that to the printing plate which is lastly fed the damping water, sometimes there occurs only smaller amount of the damping water being fed in comparison with that of fed to other printing plates.

In addition, it is preferable to feed and apply the ink onto the surface of the printing plate immediately after the damping water having been fed and applied thereto, however, the holder on which ink rollers for four colors etc. are mounted becomes considerably longer, so that relatively longer time interval is required for feeding and applying the ink to the rollers after the damping water having been supplied to the rollers. Accordingly, sometimes there occur cases in which prior to feeding and applying the ink onto the rollers, the amount of the damping water to be supplied thereto is in short, because of evaporation thereof.

In view of the afore-described disadvantage, it is proposed that instead of the damping roller common to all the colors, if rollers for feeding and damping water to each of the colors are provided, the disadvantage can be solved.

However, if the machine is constructed so that, by providing a damping means of usual construction, the damping water may be fed to each of the damping rollers of the respective colors, the stroke of the holder becomes too longer, which results in making the whole machine large scale. Further, in the case of a plurality of damping means being disposed on the holder corresponding to each of the damping rollers, not only the machine becomes very complicate but also the holder becomes larger size and not practical.

The damping water supplier of the multi-color lithographic proofing machine according to the present invention comprises, in order to overcome the problems above-described, a damping means, a plurality of tables, and along the upper surface of a frame on which the same number of ink feeding means as that of the plurality of tables are arranged, a holder which supports damping roller common to each of colors, a blanket cylinder and ink rollers of the same number of sets of those of the table, and said damping water supplier moves the holder reciprocally, said damping water supplier is characterized in that in addition to the first damping roller common to each of the colors, at least a second damping roller is approximately attached to the side of the tables etc. and pivotally supported thereto, and at an appropriate position between the table and the ink feeding means a water retention means at least the surface of which is covered with materials having water retention characteristics is disposed so that an appropriate amount of water may be supplied from the water retention means to each of the damping rollers, when they are passing the position.

Summary of the invention The present invention is achieved to solve disadvantages of the conventional multi-color lithographic proofing machine. In view of the foregoings, it is an object of the present invention to provide a multi-color lithographic proofing machine having an improved damping water supplier which comprises a damping means, a plurality of tables, and along the upper surface of a frame on which the same number of ink feeding means as that of the table are arranged, a holder on which damping rollers, a blanket cylinder and ink rollers sets of the same number as that of the plurality of the table are supported, and moves the holder reciprocal ly.

In the present invention by the damping means a part of damping water fed to the damping roller common to each of colors is supplied to each of the second damping rollers of respective colors.

Brief description of the drawings Figure 1 is a schematic construction view of the four-color lithographic proofing machine to which the present invention is applied; Figure 2 is a diagram showing up and down states of each of means supported on the holder; and Figure 3 is a schematic construction view of the conventional multi-color lithographic proofing machine.

Description of the preferred embodiment Fig. 1 is a schematic construction view of a fourcolor lithographic proofing machine to which the present invention is applied.

A holder (48) is mounted on the upper surface of a frame (46) on which the first color table (41), the second color table (42), the third color table (43) and the fourth color table (44) are arranged, and the holder is reciprocally moved along the frame (46).

On the holder (48) a blanket cylinder (50) on which four sheets of blankets (51), (52), (53) and (54) are applied, the first damping roller (60) common to each of the colors, the second damping rollers (61), (62), (63) and each of the colors, the second damping rollers (61), (62), (63) and (64) respectively for the first, the second, the third and the fourth colors, and ink rollers (71), (72), (73) and (74) respective for the first, the second, the third and the fourth colors are pivotally supported. They roll over the surface of a desired table in synchronism with the movement of the holder (48).

Then, in order to roll the blanket cylinder (50) on the plate applied onto any of the tables (41), (42), (43) and (44) without causing relative slippage therebetween, a rack is mounted on the frame (46) side and a pinion is mounted on the blanket cylinder (50) side, so that certain rolling conditions may be obtained therebetween.

Further, on the holder (46) a printing cylinder (58) is pivotally supported. Opposing to the blanket cylinder (50) there is provided a paper gripper (56) which serves to apply the printing paper onto the blanket cylinder (58).

Here, the blanket cylinder (50) has a diameter of a size as four times as that of the printing cylinder (58), and with mechanism, such as spur gear etc.

(not shown), it is adapted to rotate with the same circumferential speed as that of the printing cylinder (58).

The peripheral surfaces of all of the abovementioned rollers, i.e., the first damping roller (60) common to all the four colors, the first color, the second color, the third color and the fourth color rollers (61), (62), (63) and (64) are covered with good water retentive material such as molten etc.

At an opposite position in the vicinity of the left side end of the frame (46) to that of the first damping roller (60) comes to be located, when the holder (48) reaches at a stroke end shown by a dashed line in Figure 1 (hereinafter, refer to "left terminal end of the stroke"), a damping means (66) is provided. At the right end of the frame (46) there are provided a first color ink supplier (81), a second color ink supplier (82), a third color supplier (83) and a fourth color supplier (84) at each of positions opposite to respective positions where a first color, a second color, a third color and a fourth color ink rollers (71), (72) and (74) comes to be located, when the holder (48) reaches at the other stroke end shown by a solid line in Figure 1 (hereinafter, refer to "right terminal end of the stroke").

The reference number (68) is a water distributing plate disposed at an opposite position to that of the first damping roller (60) being positioned as a water retention means, and same as those damping rollers (61), (62), (63) and (64), it is covered with materials of good water retentive characteristics, such as molten etc.

In the case of carrying out four colors proofing print, the first color plate is applied onto the first color table, the second color plate onto the second color table (42), the third color plate onto the third table (43) and the fourth color plate onto the fourth color table (44), and further, onto the peripheralsurface of the blanket cylinder (50) a first color blanket (51), a second color blanket (52), a third color blanket (53) and a fourth color blanket (54) are applied, and all o- the first, second, third and fourth color ink suppliers (81), (82), (83) and (84) are filled with respective color inks. In the damping means (66) damping water is supplied. Thus, the holder (48) is reciprocally traveled.

Here, the damping rollers (60), (61), (62), (63) and (64), the ink rollers (71), (72), (73) and (74) and the blanket cylinder (50) pivotally supported to the holder (48) contact with predetermined tables etc.

only at required areas as the holder (48) reciprocally moves, but at other areas they must be kept from contacting with the tables or the like.

in Figure 2 there is a diagram shown status of each of the means pivotally supported to the holder (48) is to move up and down according to the reciprocal movements of the holder (48). In the diagram each of solid lines shows, from the top in regular order, respective up and down status of the following members, when each of them moves in the direction shown by each of arrow lines, that is, the blanket cylinder (50), the first damping roller (60), the first color damping roller (61), the second damping roller (62), the third color damping roller (63), the fourth color damping roller (64), the first color ink roller (71), the second color ink roller (72), the third color ink roller (73) and the fourth color ink roller (74).

Areas (A),...(K) shown in Figure 2 are same as those of shown in Figure 1. The area (A) is a damping water supplying area of the left side of the frame, the area (B) is an area of the first color table, the area (C) is a second color table areas, the area (D) is a third color table area, the area (E) is a fourth color table area, the area (F) is a rotation area of the blanket cylinder (50) which will be described hereinafter, the area (G) is a water distribution plate area, the area (H) is a first color ink supplying area, the area (I) is a second color ink supplying area, the area (J) is a third color ink sup plying area and the area (K) is a fourth color ink supplying area.

The above described up and down movements are carried out by providing a plurality of cams on both sides of the frame (46), and by driving an air cylinder, basing upon travelling direction and trav eling position of the holder (48), connected to the both sides of each of the rollers. However, these mechanisms are well known matters for the per sons skilled in the art, and have been already dis closed in the Japanese Patent Laid-Open Publication No. 54-15020, Japanese Utility Model Publication No. 54-4402, so that further description is abbreviated.

Accompanying with the reciprocal movements of the holder (48), the first damping roller (60) which is fed damping water from the damping means (66) at the left end of the stroke contacts with the water distributing plate (68), whereby damping water contained in the roller (60) is uniformly dis tributed and a part of damping water is supplied to the water distributing plate (68).

Then, each of the inks is supplied to the respec tive ink rollers (71), (72), (73) and (74) from the ink suppliers (81), (82), (83) and (84), respectively.

Nextly, during the holder (48) traveling to the left end of the stroke, damping water and each of the color inks are fed to each of the printing plates on the respective tables (41), (42) (43) and (44).

The first damping roller (60) descends at those areas (F),...(B) areas shown in Figure 2 to feed damping water to the surface of each of the printing plates.

The second damping rollers (61), (62), (63) and (64) which are supplied damping water from the water distributing plate (68) descend at the areas (B), (C), (D) and (E) shown in Figure 2 and supply damping water to thE surfaces of the respective printing plates, and that unify damping water on each of the printing plates.

Further, the ink rollers (71), (72), (73) and (74) descend at the areas (B), (C), (D) or (E), and supply the surfaces of the printing plates with inks.

All of the above described operation is carried out overlappingly, and when the holder (48) moves to the left end of the stroke, damping water supply and ink feeding to the surface of each of the printing plates finish.

At the left side end of the stroke, as mentioned the above, from the damping means (66) damping water is supplied to the first damping roller (60).

In succession, while the holder (48) travels to the right side end of the stroke, the blanket cylinder 150) descends at the areas (B).,,,(E) shown in Figure 2, and inks are transferred on the corresponding blankets (51), (52), (53) and (54) which are applied onto the blanket cylinder (50) from each of the printing plates.

When the holder (48) returns to the right side end of the stroke, the paper gripper (56) of the printing cylinder (58) is fed the printing paper and engagement between the pinion of the blanket cylinder (50) and the rack of the frame (46) is released.

Then, the blanket cylinder (50) is driven to one rotation by driving means such as motor etc. (not shown). Then, in synchromism with rotation of the blanket cylinder (50) the printing cylinder (58) on which the printing paper is applied rotates four revolutions, and each of the inks on the respective blankets (51), (52), (53) and (54) is transferred orto the printing paper on the printing cylinder (58) and printing is carried out.

Further, while the above described operation is being performed, feeding ink from each of the ink feeding means (81), (82), (83) and (84) to the respective corresponding ink rollers (71), (72), (73) and (74) is, of course, done, as above mentioned.

As described the above, while the holder (48) reciprocally travels on the frame (46) four color proof printing is completed The above description relates to a case that a four color lithographic proofing machine in which a plurality of blankets are applied onto a blanket cylinder is practically used. Of course, it is also possible to apply each of blankets for respective colors to a multi-color lithographic proofing machine.

In this case positions of the damping rollers of respective colors may be disposed any sides of the blanket cylinder (22), (24). What is important lies in that at least one damping roller is disposed so that it may correspond to each set of ink rollers.

The damping water supplier of the multi-color lithographic proofing machine according to the present invention is constructed as the afore-mentioned and has effects as follows.

(1) A damping roller is provided at each of ink rollers, so that uniform water supply on the surface of the printing plate can be achieved.

(2) Damping water supply can be performed immediately prior to applying and feeding inks to the surfaces of the printing plates, so that there is no apprehension of damping water having been evaporated prior it to feeding inks.

(3) Damping water is supplied to the damping roller of each set of the ink rollers through the water retention means, so that size of stroke of reciprocal movements of the holder can be shortened.

(4) It is unnecessary to provide a damping means on the holder, so that the holder can be made smaller and more compact.

Claims (2)

1. A multi-color lithographic proofing machine having a damping means, a plurality of tables, ink feeding means of the same number of said tables, a frame on which said damping means, said tables and said ink feeding means are arranged and a holder which pivotally supports damping rollers, a blanket cylinder and ink rollers same number as that of said plurality of tables, said holder being reciprocally traveled along the upper surface of said frame, characterized in that: at least one damping roller is pivotally supported at every set of a damping roller common to each of colors and each of ink rollers on said holder, at a position between said table of the frame and said ink feeding means a water distributing plate which is supplied water from said first damping roller and supplies damping water to the second damping rollers, when they are passing therethrough.

2. A multi-color lithographic proofing machine according to claim 1, wherein the second damping roller is provided at the table side of the ink roller and adjacent thereto.