JPH0228467B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dampening fluid supply device or system for an offset lithographic printing press.

The main elements of an offset press are a plate cylinder, a blanket cylinder, a dampening system, and an inking system. A printed printing plate with a photographic image is mounted around the plate cylinder. The image is defined by the density of lipophilic dabs on a hydrophilic background, and the intensity or darkness of the image is directly proportional to the density of such dabs.

The function of the humidification system is essentially to sufficiently wet only the background part of the plate with the aqueous solution. Fatty ink is then rolled onto the plate, which adheres only to the oleophilic dabs to create an inked image that is transferred to the adjacent blanket cylinder and then to the paper surface to be printed.

The humidification system constitutes an important element of this press. If the amount and application of the dampening fluid is not accurate, the dampening fluid and ink will inaccurately coat the relevant hydrophilic and oleophilic zones, ultimately damaging the printed image. be. In a conventional humidification system, a water supply roller (ductor) reciprocates from the humidification liquid reservoir to the humidification roller row.
By adjusting the reciprocating speed frequency of
Control the amount of solution delivered to the foam cylinder adjacent to the plate cylinder. By adjusting the pressure between the foam roller and the plate cylinder, the amount of solution actually delivered to the plate is then controlled. Excess liquid is nipped between the form roller and the plate cylinder and accumulates on the form roller. This excess liquid may have to be reduced in quantity by reducing the frequency of the reciprocating movement of the water supply roller. Otherwise, it would build up to the point of over-wetting the printing plate.

Additionally, the foam roller is coated with a highly absorbent material, such as molleton, in order to absorb a sufficient amount of dampening fluid for application to subsequent printing plates. However, this coating eventually becomes clogged with ink and collects dampening fluid until it must be replaced, ultimately inhibiting the delivery of dampening fluid to the background zone. Because of these and other deficiencies of prior art humidification systems, it is difficult to obtain sharp printed images without a very high degree of control and care.

The object of the present invention is to provide a dampening fluid supply device for offset lithographic printing presses in which the above-mentioned problems can be overcome or at least appreciably reduced.

Therefore, in order to achieve the above object, the present invention provides a dampening liquid supply device for an offset lithographic printing press having a plate cylinder around which a lithographic printing plate is attached and which can be fixed in a recessed portion. a frame mounted on the printing press adjacent to the plate cylinder; a form roller rotatably supported on the frame so as to contact the printing plate on the plate cylinder; a metering roller rotatably supported by the frame in pressure contact with the plate cylinder; and a metering roller cooperating with the foam roller to form a reservoir for dampening liquid. sealing means mounted on the frame, the foam roller and metering roller having ink-adhesive surfaces, and the surface of the metering roller having a significantly less elasticity than the surface of the foam roller; means for pressing the form roller into contact with a printing plate on the plate cylinder; and means for pressing the metering roller into contact with the form roller with a force sufficient to compress the surface of the form roller. drive means for rotating the form roller and metering roller at a one-to-one surface speed with respect to each other and the plate cylinder; and means for supplying a dampening liquid to the liquid reservoir, thereby increasing the humidity in the liquid reservoir. It is characterized in that the liquid is continuously mixed with the ink picked up from the printing plate by the action of the metering roller and the form roller.

According to the above arrangement and configuration, the dampening liquid is actually applied by adjusting the pressure between the first roller, that is, the foam roller, and the second roller, that is, the metering roller, and between the first roller and the plate cylinder. The amount of can be controlled. Excess moisture retained on the first roller is continuously returned directly to the sump. If the device of the invention is used with a conventional plate cylinder having a recessed clamping section for mounting a printing plate, excess liquid caught between the cylinder and the first roller will also be absorbed into the recess. Each pass through the attached compartment directly returns to the sump. Excessive accumulation of liquid is therefore not easily possible, so that the plates are not possibly overwetted.

Furthermore, since the reservoir is in direct contact with the first roller, there is no need for an absorbent moretone coating on the roller to ensure proper fluid delivery.
Also, since the form roller and metering roller have ink-adhesive surfaces, the ink picked up from the printing plate is continuously mixed with the dampening liquid in the reservoir by the action of these rollers. At this time, since the ink and the dampening liquid are made of different bases, they do not form an emulsion, but form a liquid mixture that can be separated from each other. This liquid mixture is then broken into uniform droplets under the pressure between the two rollers. The droplets are applied onto a printing plate where they are separated into ink droplets and dampening liquid droplets. Therefore, there is no need for conventional efforts to prevent or minimize the transfer of ink from the printing plate to the form roller and metering roller during operation.

The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings, in which: FIG.

As shown in FIG. 1, a plate cylinder 1 is driven within a machine frame 12 by a drive gear 11.
The press includes 0. The dampening fluid supply device itself consists of two end housings 13 and a covering top cover 1 extending between these end housings.
It is surrounded by a frame containing 4 and 4. The dampening fluid supply device is attached to the press housing in a conventional manner. Various presses are provided with accessories for the dampening liquid supply device. The pressure between the plate cylinder 10 and the form roller 20 is regulated by these accessories.

The dampening liquid supply device includes a foam roller 20 mounted parallel to the plate cylinder 10 and in contact with the cylinder, and a second roller 22 disposed parallel to and tangentially to the foam roller 20. and a tangent line 27 between the form roller 20 and the second roller 22 and between these rollers.
A dampening fluid reservoir 26 (shown in FIG. 3) located above (FIGS. 4 and 5);
A liquid reservoir bottle 24 is placed directly above the liquid reservoir bottle 24.

As shown in FIG. 6, the liquid reservoir bottle 24 is a closed container having a core bar 29 extending horizontally in an arc shape over substantially the entire length of the second roller. The dampening liquid is discharged through an outlet or feed pipe 30 located approximately in the center of the entire length of the core metal. According to this device or arrangement, the liquid level in the liquid reservoir 26 is
As the water drops below the limit or lower end 31 of the bottle, air enters the bottle 24 and drains the dampening liquid in the bottle until the liquid level in the reservoir 26 completely covers the lower end 31 of the feed pipe 30. It is possible to discharge it. The sump bottle 24 therefore serves to automatically maintain the liquid level in the sump 26 at a specified level. The lower end of the feed tube 30 is generally submerged below the liquid level in the liquid reservoir 26. Since it has a slightly arcuate shape, the core bar maintains a constant liquid level in the container over the entire length of the roller. Therefore, the dampening liquid does not foam. This eliminates the possibility of liquid bubbles forming in the feed tube 30 and leaving part of the reservoir dry. If part of the liquid reservoir becomes liquid-free, the roller will be rotated without being supplied with a sufficient amount of liquid, and clear printing will not be achieved.

FIG. 2 illustrates a seal used to prevent leakage from a reservoir. 1st, 7th and 8th
The figure shows the location of the seal in the dampening fluid supply device. The seal comprises a seal carrier 33 and a seal plate 36. Seal carrier 33
are preferably made of metal, while sealing plate 36 is preferably made of plastic. Seal plate 36 forms a perimeter seal with second roller 22 and also forms an end seal with roller 20.

In the seal shown in FIG. 1, the seal is attached to end housing 13 by bolts 35 passing through slots 34. 7th and 8th
In the seal shown, a tension spring 38 is mounted through the opening 37. Opposite ends of the spring 38 are secured to the end housing 13 (see FIG. 7). As shown in FIG. 8, another spring 39 is biased against the seal carrier 33 adjacent the end housing 13. The seal carrier 33 and therefore the carrier and the seal plate 36 are connected to the spring 38.
is urged downward and toward the second roller 22 by the tension of the roller 22 . At the same time, bias spring 3
9 urges the seal carrier 33 and thus the carrier as well as the seal plate 36 into abutment against the end of the foam roller 20 . In this way, the seal becomes progressively worn but remains effective in its function. Even if the second roller 22 causes wear on the seal plate 36, the tension spring 38 ensures a tight circumferential seal by pulling the seal plate towards the second roller. Even if the form roller 20 causes wear on the seal plate 36, the bias spring 39 biases the seal against the end of the form roller 20 to maintain an effective end seal.

Adjustments to control the pressure between the form roller 20 and the second roller 22 are made using a lock nut 43.
This is done by adjusting the screw 42 screwed together through the screw (see FIG. 9). screw 42
extends through the lock nut 43 and the wall of the end housing 13 and into the cam 44. By adjusting the screw 42, the cam 44 attached to the second roller 22 moves towards the second roller with a slight change in its eccentric arcuate path. Adjusting the screw in the opposite direction will slightly change the eccentric arcuate path of the cam so that the second roller 22 is spaced from the form roller 20. In this way the pressure between both rollers is controlled.

As shown in FIG.
It is attached to the roller pressure gauge 45 by a. A roller pressure gauge 45 is provided projecting from the end housing and is graduated at regular intervals to provide a relative reading of the pressure between the form roller and the second roller. being done. An indicator 46 provided on the end housing 13 makes it possible to measure the relative pressure value between the two rollers.

The operator can loosen or tighten screw 47 and adjust the position of roller pressure gauge 45 at zero point. Locknut 43
The pressure value between the second roller and the foam roller can be controlled by loosening the screw 42 and adjusting the screw 42.

Form roller 20 has an axle 50 which is compacted in a tubular body part 51 . A cylindrical shell 52 is mounted on the tubular body portion 51. The shaft 50 extends from the roller 20 at both ends and passes through a pair of bearings 53 (FIG. 8), and is mounted within the end housing 13. Bearing 5
3 rotates freely around the axis 50.

The second roller 22 has an axle 60 which is compacted within the tubular body part 61 . Tubular body portion 61
is compacted within the cylindrical shell 62. axis 60
extend from both ends of the roller. At the end of the shaft where the gear is mounted, the shaft 60 extends through a directional bearing and another bearing mounted within the cam 44. The opposite shaft end extends through a spacer (not shown) and a bearing (not shown) and is mounted within the end housing 13.

The gear 66 is fitted into the bearing 53 and meshed with the drive gear 11. The second gear 68 is fitted into the center of the directional bearing 63 and engages with a first driven gear (not shown). Therefore, in this assembly, the driving gear 11 is the first driven gear 66
The first driven gear 66 drives the second driven gear 68.
Rotate. Since the second driven gear 68 is rigidly coupled to the directional bearing, rotation of the gear 68 locks the directional bearing about the axis, thereby causing rotation of the second roller. The rotation of roller 22 causes foam roller 20 to rotate simultaneously with roller 22 due to the pressure between the two rollers 20 and 22. Furthermore, since the form roller 20 is in contact with the auxiliary rotating plate cylinder 10, the rotation is assisted. When the gear 68 is rotated in the opposite direction, the directional bearing is released and the second roller 22 is prevented from rotating.

In summary of operation, drive gear 11 rotates plate cylinder 10 and first driven gear 66 . The first driven gear 66 rotates the second driven gear 68, which transmits its motion to the shaft 60 of the second roller 22 via a directional bearing. In operation, the pressure between the shells 52 and 62 of the foam roller 20 and the second roller 22 is regulated by the screw 42, and the pressure between the shells 52 and 62 of the first roller 20 is adjusted by the screw 42.
The pressure between the two is adjusted by conventional attachment means including bolts or cams such that the form roller 20 is driven by both the second roller 22 and the plate cylinder 10. As will be appreciated, the preselected degree of pressure between rollers 20 and 22 also determines the amount of liquid metered from reservoir 26 to foam roller 20. Similarly, the degree of pressure between the form roller 20 and the plate cylinder 10 determines the amount of metering fluid actually applied to the printing plate 85 on the plate cylinder 10.

FIG. 10 shows the attachment means between the dampening liquid supply device and the press. The dampening liquid supply device includes a lever arm 18 connected to the housing 13 via a stud 19, as indicated by a dashed line 71.
can be raised and lowered pivotally around screw 70 by. The housing 13 is a tension spring 73
The adjusting bolt 72 is biased to the lowered position by the adjusting bolt 72. By adjusting the bolt 72 and selecting the spring 73, the degree of pressure between the plate cylinder 10 and the form roller 20 is varied.
A screw 70 secures a connecting arm 74 between the press and the dampening liquid supply device. The connecting arm 74 has two screws 75
and 76 to the press.

The relative rotation of form roller 20, second roller 22, and plate cylinder 10 is shown in FIG. The printing plate 85 is wrapped around the plate cylinder 10 and secured in a recess 86. After the dampening system, ink is applied to the printing plate 85 by a bank of inking rollers (not shown). In FIG. 4, the row of inking rollers will be placed on the right side of the plate cylinder 10. After the ink has been applied to the printing plate 85, the image thereby created is transferred to a blanket cylinder and then printed onto a printing paper.

The best printed image will result if the amount of dampening liquid applied to printing plate 85 is adequate. Therefore, in theory, the pressure between the form roller 20 and the second roller 22 should be adjusted such that the amount to be applied to the printing plate 85 is metered through the form roller 20 and the pressure between the form roller 20 The pressure between the printing plate 85 and the plate cylinder 10 must be precisely adjusted to apply the above amount to the printing plate 85. In practice, such precise adjustment is not possible and constant monitoring is required.

According to this embodiment, at the start of printing, the ink is quickly returned to the dampening liquid in the reservoir by the rollers 20 and 22, and a mixture of ink and dampening liquid is formed. At this time, since the ink and dampening liquid are made of different bases, they do not form an emulsion.
Form a mixture that can be separated from each other. The liquid mixture is broken into uniform droplets under the pressure between both rollers. The droplets are applied onto the printing plate 85 by the form roller 20 and separated according to the adsorption selectivity of the printing plate 85 for ink and dampening liquid. This results in a precisely inked image on the printing plate after several revolutions of the plate cylinder, and a good product can be obtained rapidly. A slight excess of liquid is metered through the tangent 27 between the foam roller 20 and the second roller 22. However, the form roller 20 and plate cylinder 10 are adjusted so that only the proper amount of liquid is applied to the printing plate 85. Some excess remains on the foam roller 20 as surface moisture and is removed from the liquid reservoir 2.
6, while a droplet 90 is formed by the excess residual portion at the point where the form roller 20 contacts the plate cylinder 10, as shown in FIG. However, this droplet
Recess 8 of plate cylinder 10 as shown in the figure
6 is returned to the liquid reservoir 26 each time it circulates. The reservoir 26 is located adjacent to the form roller 20 but beyond its highest tangent in the direction of rotation so that dampening fluid does not accumulate where it could drip onto the printing plate 85. This embodiment thus provides a means to continuously apply a constant amount of liquid to printing plate 85 without requiring careful monitoring and control by an operator.

This embodiment also has other advantages. Each printing plate 85 necessarily contains heavily inked and minor inked zones depending on the intensity of the image ultimately to be produced. As a result, after some use, the foam roller 20 and possibly the second roller in the dampening train of rollers will have correspondingly more and less inked zones. Such a phenomenon is caused by the fact that the amount of dampening liquid actually applied to any particular portion of the printing plate 85 by the form roller 20 is
Advantageously, it is approximately inversely proportional to the density of the ink on the corresponding portion of roller 22. For example, a large ink deposit zone on the foam roller 20 may actually deposit a small amount of dampening fluid into a high ink deposit zone on the printing plate 85 compared to the amount of liquid applied by a small ink deposit zone. This is a favorable result. This is because, as explained in the foregoing technical background, the intense image represented by the heavily inked zone requires only a small amount of dampening solution for clarity and sharpness.

However, known foam rollers generally have a highly absorbent cover, such as a Moreton coating, in order to direct a sufficient amount of dampening liquid, and these covers do not absorb much of the printing plate due to the extremely low dampening liquid ratio. Ink easily stains areas that spoil the image above. In such cases, the operator must replace the soiled cover with a new one, which is a time consuming and inefficient task. Similarly, the operator must change the cover when replacing the printing plate with another different image. An otherwise constantly dirty cover will give a dirty band to the low density image area of the new printing plate, resulting in a smudged image.

According to this embodiment, sufficient supply of the dampening liquid can be achieved by connecting the tangent line 2 between the foam roller 20 and the second roller 22.
7 and the foam rollers, an absorbent cover as described above is unnecessary and not used. Shells 52 and 62 of form roller 20 and second roller 22 are preferably made of rubber and metal, respectively. However, other materials can also be used.

Since there is no absorbent cover (indeed, it is preferred not to have any ink-absorbing material in any part of the device), the ink on the rollers 20 and 22 is only on their surfaces and does not interfere with printing. It is continuously replaced with the ink on the plate. In this way, during operation of the press, the ink on the dampening rollers 20 and 22 does not build up and become excessive. Furthermore, when a new printing plate is installed in the plate cylinder, after a short time the ink on the heavily inked zones of the form roller 20 and the second roller 22 is completely removed and the new inked zone is replaced by the new printing plate. This appears on rollers 20 and 22 corresponding to a heavily inked zone.

Another dampening fluid supply system is shown in FIG. This device includes a liquid reservoir 100 and a liquid reservoir bottle 101.
, a second roller located parallel to and in contact with the form roller 103 at a tangent 104 , and a second roller located parallel to and in contact with the form roller 103 at a tangent 106 .
05 and a form roller 103 located parallel to and in contact with the roller. The second roller 102 is located within the liquid reservoir 100 and the liquid reservoir 107 is located above the tangent line 104 between the foam roller 103 and the second roller 102.
rotates to continuously deliver dampening fluid to the The pressure between the form roller 103 and the second roller 102 is increased by measuring a slight excess amount of liquid from the liquid reservoir 107, and increasing the pressure between the form roller 103 and the liquid formed between the tangent line 104 and the tangent line 106 in the rotation direction. The distribution arc 108 is adjusted to provide a distribution arc 108. The pressure between the foam roller 103 and the plate cylinder 105 is adjusted to apply the appropriate amount of the excess amount to the printing plate 109, which is sandwiched between the foam roller 103 and the plate cylinder 105. The excess 110 is tangent 1 in the direction of rotation.
The liquid is returned by a liquid return arc-shaped portion 115 of the form roller 103 formed between 06 and the tangent line 104. The tangent line 104 and the liquid reservoir 107 are arranged beyond the uppermost tangent line 116 of the form roller 103 in the direction of rotation. Storage tank 100
Since the liquid inside is used, it is continuously exchanged with the liquid in the liquid reservoir bottle 101 as described above.

The foam roller 103 is slightly shorter than the second roller so that the liquid will flow to the foam roller 10 when the sump 107 reaches the overflow level.
The liquid is regularly exchanged from the reservoir 107 to the storage tank 100 along the rotating surface of the second roller that is in contact with the end of the liquid. This configuration eliminates or simplifies sealing of the end 118 of the form roller 103.

Figures 12 and 13 show other embodiments of sealing means that can be used to prevent leakage from the reservoir. This sealing means is a seal carrier 233
and a seal 236. A flange or lip 237 is located along one edge of the seal carrier. The seal 236 is attached to the carrier 23 with a lip 237 engaging one side of the seal.
It is free to move or float with respect to the carrier 233, except that it is held in relative position on the carrier 233. A projection or pin 239 is provided on the surface of the carrier opposite to the seal 236. spring 2
41 is arranged around the protrusion 239 to hold the seal carrier 233 between the form roller 20 and the second roller 22.
It acts to strengthen the. Protrusion 23
9 and spring 241 are placed within an opening 243 provided in end housing 13. Protrusion 2
By positioning 39 within opening 243,
Seal carrier 233 is maintained in proper relationship to form roller 20 and second roller 22.

The top of the seal carrier 233 is provided with a flange 245 that projects beyond the top of the seal 236. The spring 2 engages with this flange 245.
47 are arranged. The other end of spring 247 enters a hole 248 located on the top surface of seal 236.

An opening 249 is provided at the lower end of the seal carrier 233. A member 251 is disposed in end housing 13 and extends toward form roller 20 . An end housing 13 is provided at the end of this member.
An opening 253 is provided at a location spaced apart from. A spring 255 is connected between the opening 249 of the seal carrier 233 and the opening 253 of the member 251. The member 251 is typically arranged at an angle such that the spring biases the seal carrier against the foam roller 20.

In operation, the seal 236 is unconstrained and floats on the seal carrier 233 during operation of the dampening fluid supply system. A spring 241 arranged on the projection 239 presses the seal carrier 233 and the seal 236 against the foam roller 20 and the second roller 22 . A spring 247 located between the flange 245 and the top surface of the seal 236 urges the seal against the cylindrical surfaces of the foam roller 20 and the second roller 22. A spring 255 connecting between the opening 249 in the seal carrier 233 and the opening 253 in the member 251 moves the seal carrier 233 and the seal 236 against the roller, in particular the second roller 2
It is pressed against 2. Lip 237 of seal carrier 233 engages seal 236 and presses the seal against second roller 22 as spring 255 biases the seal carrier against second roller 22. The spring is configured such that the seal self-adjusts to continuously provide a proper seal with the first and second rollers during operation of the dampening fluid supply system.
Activating the seal.

Preferably, the second roller 22 in this embodiment has a copper surface. The ink used for printing is deposited on the surface of the copper roller, and this ink is retained in the image zone of the second roller 22 and the foam roller 20. Retaining the ink in the image zone of the roller improves the quality of prints made in lithographic printing methods that utilize the dampening system of the present invention.

It has been found advantageous to provide the second roller 22 with a reinforced end made of chrome, stainless steel or other suitable material. The reinforced end of the second roller 22 is provided to engage a seal 236 that is placed in contact with the end of the roller. The reinforced end reduces wear on the seal zone of the second roller. Therefore, the life of the second roller is significantly increased by providing the second roller 22 with a reinforced end.

FIG. 14 shows another embodiment of the dampening liquid supply device of the present invention. In this embodiment, the form roller 20 has a sprocket 203 mounted on a support shaft 205 thereof. This sprocket engages the drive gear 11 for the plate cylinder 10, so that the form roller is directly driven by the plate cylinder 10. The second roller is caused to rotate by frictional contact with the form roller 20. Directly driving the form roller 20 is advantageous since there is little chance of the form roller slipping or moving relative to the plate cylinder 10. The printing material is therefore less likely to be soiled by slips between the form roller and the plate cylinder.

FIG. 15 shows another embodiment of the liquid reservoir bottle and the core member for supplying the dampening liquid to the foam roller 20 and the second roller 22. In FIG. In this embodiment, the reservoir bottle 224 is disposed in conjunction with an arcuate core member 200 that extends horizontally over substantially the entire length of the second roller. A central opening 230 is provided at substantially the center in the longitudinal direction of the core member. There are two side channels 22 on both sides of the central opening 230.
9 is placed. This side channel has a central opening 230
It is located approximately equidistant from the The central opening 230 and the two side channels are located generally along the longitudinal axis or centerline of the core member 200.

A valve 270 is provided in the neck of the bottle 224 and cooperates with the central opening 230 and the two side channels 229 to bring liquid into the reservoir 26 . valve 270
has a plunger 271 having a passage 273. This passage has an inlet opening 272 and an outlet opening 27
It has 4. This passage communicates the interior of the bottle 224 with the central opening 230 of the core member 200.
The plunger also has a cutout 276 along its side defining a passageway 278. Passage 2
78 communicates the interior of the bottle with the two side channels 229 of the core member 200. A spring 275 is disposed around the outside of the plunger 271. One end of this spring engages the shoulder 277 of the valve, and the other end engages an O-
It engages ring seal 279. Spring 275 forces plunger into bottle 2 such that O-ring seal 281 contacts face 283 of the valve.
It is pushing in the direction away from 24. O-ring 281 forms a seal with surface 283 to prevent liquid from flowing out of the bottle.

When the bottle 224 is placed on the core member 200, the end of the plunger remote from within the bottle engages the central opening 230. When the bottle is placed into engagement with the central opening 230, the plunger is displaced relative to the bottle 224. Displacement of the plunger causes inlet opening 272 to communicate with the bottle interior, so that passageway 273 connects the bottle interior to central opening 230 . A passage 278 also connects the bottle interior to the two side passages 229.

When the level of the humidifying liquid reservoir 26 drops below the discharge end 231 of the central opening 230, air flows through the central opening 2.
30 into the bottle 224 and the liquid within the bottle flows out of the bottle, along passage 278 and into the sump 26 through the side passage 229. Liquid continues to drain from the bottle 224 until the level of the reservoir 26 completely re-covers the drain end 231 of the central opening 230. In this way, the liquid reservoir bottle 224 and the core member 2
The 00 configuration automatically holds reservoir 26 at a predetermined level. This bottle and core configuration improves the flow of dampening fluid into the reservoir 26. In addition, narrower casting of the core member is possible, which allows a narrower bead of dampening liquid to be placed between the foam roller 20 and the second roller 22.
A narrow dampening liquid bead allows the core member to be placed further away from the rollers, thereby increasing the gap between the core member and the rollers. If the distance between the core member and the roller increases, it becomes difficult for the surface of the core member and the surface of the roller to come into contact with each other.

[Brief explanation of drawings]

In the accompanying drawings, FIG. 1 is a cutaway perspective view illustrating one embodiment of the dampening liquid supply device according to the present invention, FIG. 2 is a perspective view illustrating a sealing portion of the device shown in FIG. 1, and FIG. The figure is a sectional view of the device shown in FIG.
4 and 5 are schematic diagrams of the moisturizing roller and plate cylinder shown in FIG. 1, and show how the excess liquid received in the nip is circulated back to the container; FIG. 1 is a longitudinal sectional view of the device shown in FIG. 1, FIG. 7 is a sectional view taken along line 7-7 in FIG. 1, and FIG. 8 is a sectional view taken along line 8-8 in FIG.
Figure 9 is a sectional view taken along line 9-9 in Figure 1.
FIG. 0 is an end view of the device shown in FIG.
11 is a schematic sectional view showing one modified embodiment of the dampening liquid supply device according to the present invention, and FIGS. 12 and 13 are diagrams showing still another dampening liquid supply device according to the present invention. FIG. 14 is a perspective view showing a sealing device portion in one embodiment, FIG. 14 is a drawing showing a sprocket device portion in still another embodiment of the device of the present invention, and FIG. It is a drawing showing a wet liquid feeding system.
The correspondence relationship between the main parts of the illustrated device of the present invention and the reference numerals is as follows. Plate cylinder...10, first member...20
(first roller to form roller), second member...
22 (second roller to measuring roller), dampening liquid reservoir...26,107, sealing means...33,23
3 (seal carrier) and 36,236 (seal plate), dampening liquid container...24,101,224
(liquid reservoir bottle), core metal, core member...29,200,
Humidifying liquid supply means...30 (outlet or supply pipe),
230 (center opening), seal plate bias means...38 (tension spring) and 39 (bias spring), 241, 247, 255 (spring), plunger...271.

Claims (1)

[Scope of Claims] 1. A dampening liquid supply device for an offset lithographic printing machine having a plate cylinder around which a lithographic printing plate is attached and which can be fixed in a recessed portion, wherein the printing plate is provided adjacent to the plate cylinder. a frame mounted on the machine; a form roller rotatably supported by the frame so as to be in contact with the printing plate on the plate cylinder; and a form roller pressed against the form roller on a side opposite to the plate cylinder. a metering roller rotatably supported on the frame in a state in which the metering roller is rotatably supported on the frame; and a sealing means mounted on the frame in cooperative relationship with the foam roller and metering roller to form a reservoir for dampening liquid. the form roller and the metering roller have ink-adhesive surfaces, the surface of the metering roller has a significantly lower elasticity than the surface of the form roller, and the form roller is mounted on a plate cylinder. means for pressing the metering roller into contact with the printing plate; means for pressing the metering roller into contact with the foam roller with a force sufficient to compress a surface of the foam roller; and means for pressing the metering roller into contact with the foam roller; drive means for rotating at a one-to-one surface speed with each other and the plate cylinder; and means for supplying dampening liquid to the reservoir, whereby the dampening liquid in the reservoir is supplied to the metering roller and the form roller. A dampening liquid supply device characterized in that the dampening liquid is continuously mixed with the ink picked up from the printing plate by the action of the above. 2 a seal carrier in which the sealing means is movably supported adjacent to both ends of the foam roller and the metering roller and has a seal contact surface; a sealing member housed within each of the seal carriers; and the seal carrier. biasing means for biasing the foam roller toward an end of the foam roller and a peripheral surface at the end of the metering roller, thereby forming a peripheral seal against the outer periphery of the metering roller; 1. The dampening liquid supply device according to claim 1, wherein an end seal is formed on the roller. 3. the sealing means includes a pin member extending between the seal carrier and the end of the frame;
3. The dampening liquid supply device according to claim 2, wherein said pin member forms an axis around which said seal carrier can rotate and along which said seal carrier can move axially. 4. The dampening liquid supply device according to claim 3, wherein the sealing means includes an elastic member acting on each of the pin members to press the seal carrier toward the end of the foam roller. 5. The dampening liquid supply device according to item 4, wherein the sealing means includes a spring member connected between the seal carrier and the frame and acting to press the sealing member toward the circumferential surface of the metering roller. .