JPH04234655A - Improved non-key printing machine for non-key lithograph printing - Google Patents

Abstract

PURPOSE: To provide a keyless lithographic printing press retaining essential principle of keyless lithographic printing system by overcoming problems of prior art. CONSTITUTION: The keyless lithographic printing press comprises a blanket cylinder 10, a plate cylinder 15 with printing plate mounted thereon, a system 14 for supplying dampening water to the plate cylinder 15, a form roller 16 in rotational contact with the plate cylinder 15, an inking drum 11 in rotational contact with the form roller 16, first and second transfer rollers 13, 17 in rotational contact with the inking drum 11, a metering roller 20 in rotational contact with the transfer rollers 13, 17, and a system 30 for supplying printing fluid to the metering roller 20.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing apparatus used in a keyless lithographic printing method.

0002

BACKGROUND OF THE INVENTION In the art of high speed lithographic printing, ink is continuously transferred by a series of rollers from an ink supply to a lithographic printing plate on a plate cylinder of a lithographic printing press. The image portion of the printing plate receives ink from the last one or more of these series of inking rollers and transfers a portion of this ink as a reverse image to the blanket cylinder, and this reverse image is the correct Transferred onto paper or other material to form a recorded image. In the usual lithographic printing process, a dampening solution containing water and suitable additives is continuously transferred to the printing plate, thereby partially transferring it to the non-image areas of the printing plate, so that the water absorbs these non-image areas. This is to prevent ink from adhering to the image area. In the following description, the terms water, dampening solution refer to water plus additives or other aqueous solutions used in lithographic printing press operation.

In conventional printing presses, ink is applied continuously to all portions of the printing plate, including image area portions and non-image area portions, in varying amounts determined by a press cross-row feed control regulator. . In the absence of dampening solution, the printing plate would receive ink on both the image and non-image areas of its surface.

The surface of a lithographic printing plate, free of imaging material, has small interstices and is hydrophilic (ie, has an affinity for water) that improves the retention of water, the dampening solution, rather than ink, on the surface of the plate. It has certain characteristics. Imaging on the plate creates areas with oleophilic properties (ie, affinity for ink) that conform to the printed image. Thus, when the appropriate amounts of ink and dampening solution are applied to an imaged plate, only the ink that tends to be present in the non-imaged areas is removed from the plate. Such action generally results in continuous ink and dampening solution differentiation on the printing plate, which is important and necessary in lithographic printing processes.

Controlling the correct amount of dampening solution applied during lithographic printing has been a widespread problem in the art since the advent of lithographic printing. Lithographic printing requires continuous attention from the operator. This is because adjusting the amount of ink applied in each column requires changing the amount of dampening solution applied. Balancing variable ink coverage for each row across the width of the press with uniform dampening solution coverage across the width of the press is at best a compromise. Therefore, depending on which part of the image the operator takes as the print quality standard at a given time during the printing operation, the operator must adjust the ink application at the corresponding transverse press position. There will be. As a result, the ratio of dampening solution to ink at that location may vary from the desired value. Conversely, the operator can adjust the application of the dampening solution to obtain the best ink and dampening solution equilibrium in one inking train, but this may affect the ink and dampening solution in one or another transverse press location. The equilibrium state of the dampening solution may be adversely affected. Such adjustments tend to occur repeatedly throughout a press run, resulting in a wide range of differences, from slight to significant differences, in the quality of the printed image throughout the entire run. If these adjustments are made, the resulting image may be commercially acceptable;
It may also be unacceptable, resulting in wasted labor, materials, and press operating time.

Some commercially successful newspaper printing formats rely on banks of inking rollers that deliver dampening solution directly to the printing plate. Of these, the most notable is Rockwell International Corp. The Goss Metro, Goss Metroliner and Goss Headliner offset printing presses are manufactured by the Graphic Systems Division of Goss. In these different configurations, a dampening solution is combined with ink on an inking vibrating drum such that both ink and water are subsequently transferred to an ink-forming roller and deposited on a printing plate. It has become. In another variant, the dampening solution is supplied directly to the printing plate in the usual manner by a separate dampening roller and a dampening solution supply device. Regardless of how the dampening solution is introduced in both types of equipment, some of the dampening solution is mixed with the ink and returned to the inking roller bank, and finally introduced into the ink supply itself. It is well known that In any case, these conventional lithographic apparatuses require significant operator attention to maintain equilibrium of the ink and dampening solution and tend to result in more product wastage than desired.

Conventional apparatus and methods for correcting the inherent deficiencies in conventional lithographic printing use keyless inking devices. Some of these methods also include omitting the dampening device or eliminating operator control of the dampening device.

By omitting an adjustable inking key, the operator's attention to the control of the inking train is eliminated, thereby avoiding most of the aforementioned disadvantages of conventional lithographic printing. Keyless inking devices have been previously disclosed. For keyless inking devices, an ink that acts continuously despite the presence of up to about 40% dampening solution in the ink without allowing temporarily free dampening solution to interfere with the ink metering action. A measuring method is required. In addition, the unused portions or non-uniform portions of the ink film continuously applied to the printing plate are continuously peeled off from the return side of the inking device, and the ink film is uniformly applied to the printing plate by the supply side of the inking device. It must be possible to provide a continuous film of ink. This peeled film is not uniform across the width of the press within the ink and dampening solution composition. Since it is not economically viable to continuously dispose of the ink in the unused portions of the ink and dampening solution mixture, this mixture is then printed with the selective removal of the dampening solution from which the inked portions are printed. Should I return it to the machine?
Alternatively, the mixture of unused ink and dampening solution must be thoroughly mixed with new replenishing ink and this mixture must be refreshed by returning it to the printing press. U.S. Pat. No. 4,690,055 discloses a keyless ink applicator in which removal of dampening solution is unnecessary and no use is made during lithographic printing. It is adapted to accommodate the inevitable dampening solution in the uncoated ink, thus eliminating the need for removal of the dampening solution.

In the keyless inking device disclosed in US Pat. No. 4,690,055 (which is incorporated herein by reference), the location of the dampening device is not critical and the dampening solution is directly applied. The ink can be fed into a plate cylinder or placed in some other location such as a vibrating drum where the ink is fed. The ink circulation and mixing device receives fresh or replenishing ink as well as a combination of ink and dampening solution that is continuously returned from a doctor blade that strips excess printing fluid from a rotating metering roller. . Such an ink and dampening solution combination is generally referred to herein as a printing fluid. The printing fluid circulation and mixing device operates to ensure an inherently uniform cross-press application of printing fluid maintained in unison throughout the printing fluid dish roller,
It consists of a pump and suitable conduits, a printing fluid pan level control device and a printing fluid reservoir, which is provided with the printing fluid supplied to the metering rollers when the printing fluid is unused or has been stripped off. The volume and design ensure that the returned printing fluid is uniform in composition at any given moment despite successive cross-press dampening solution to ink ratio differences. This printing fluid circulation system continuously collects printing fluid from a reservoir and distributes it through a solid space or a series of orifices to redistribute the printing fluid uniformly across the width of the press, and the printing fluid introduced into the metering rollers. Try to give a uniform composition of the fluid. This metering roller is U.S. Patent No. 4,882,9
No. 90, No. 4,537,127, No. 4,862,79
No. 9, No. 4,567,827 or No. 4,601,2
42 (all of which are incorporated herein by reference), or of any of the types shown and described in No. 42, all of which are incorporated herein by reference, or of any pair substantially as herein defined. Can be made into abrasive lipophilic and hydrophobic metering rollers.

Although the apparatus described in US Pat. No. 4,690,055 represents a significant improvement in lithographic printing presses, the technology in this area is more or less open to the environment of the press room. This requires an ink tray device that is difficult to handle. This technique requires that the pan be placed below the meeting point of the metering roller and doctor blade so that the excess return printing fluid film that is stripped off easily falls into the pan device. Replacing pan or metering rollers is inconvenient and time consuming due to the large pan size and surrounding mounting equipment. Additionally, the countersunk roller requires a separate motor that typically drives the countersunk roller at a nominal speed that is slower than the press speed metering roller. This more or less open state of the dish arrangement causes the dish rollers, which are immersed in the pool of printing fluid, to be blown away from the surface of the printing fluid in a number of directions, including in a direction outside the area of the dish and into the press chamber. It cannot be driven at the speed of the press to release it. Also, the slow rotational movement of the countersunk roller causes excessive and severe wear when the countersunk roller and metering roller are placed in an intricate relationship with each other. Therefore, there must be a gap at the meeting point of the countersunk roller and metering roller. Controlling this gap to avoid wear of the metering roller and at the same time to completely fill the metering roller compartment is difficult to process and difficult to control over long operating times. For example, depending on the flow characteristics of the ink used, metering roller sections may be utilized in unforced conditions such as gaps between a countersunk roller and a sectioned roller, or an inking device without countersunk rollers may be used. It may be completely filled, or it may not be filled.

Depending on the particular metering roller technology utilized, a slow-moving countersunk roller driven in contact with a fast-rotating metering roller rotating at press speed may be a hard but abrasive oleophilic and hydrophobic roller. quickly wears out the metering roller surface of the element, thereby negating the element's necessary contribution to effective keyless lithography printing operations. In severely worn conditions, the metering roller has a hydrophilic or compartmentalized surface where dampening water can adversely affect the uniform and efficient metering of ink into this device. There is a danger that by losing its shape, it will lose its ability to hold ink. Thus, it is possible to incorporate all the necessary operating features as disclosed in U.S. Pat. No. 4,690,055, but overcome the disadvantageous features known above, i.e. the size of the reservoir and the need for large amounts of ink associated with using pan rollers and such large reservoirs and the inefficient metering roller compartments due to potentially rapid wear of the metering roller or gaps to the pan roller; There is a need for a keyless lithographic printing press or printing fluid device that overcomes the disadvantageous disadvantages associated with filling operations. Obviously, these limit the range of metering roller techniques that can be used advantageously.

0012

SUMMARY OF THE INVENTION The present invention overcomes the problems, difficulties and inconveniences set forth above, and moreover,
, 690,055. Therefore, with the improvement according to the invention, pans and pan rollers are omitted and at least two transfer rollers are used in the inking roller bank between the metering roller and the inking drum.

One object of the present invention is to provide an improved keyless lithographic printing machine having more transfer rollers in the inking roller bank than was required in prior art keyless lithographic printing machines. It is.

Another object of the invention is to increase the useful life of the metering roller by providing an ink transfer roller operating at press speed in place of the slow moving countersunk rollers of the prior art.

Yet another object of the present invention is to provide a pair of metering rollers operative to produce a print having even better optical density uniformity than was achievable in prior art keyless lithographic printing apparatus. is to provide transfer rollers.

Another object of the present invention is that US Pat.
An improved keyless lithography system which eliminates the countersunk roller of the inking device disclosed in U.S. Pat. The purpose is to provide a printing device.

Still another object of the invention is that the water content in the ink naturally generated by the process is kept homogenized, so that there is no free water anywhere in the ink applicator. It is an object of the present invention to provide simplified and structurally compact inking and circulation system components that function to ensure that the accumulation of ink can be avoided.

Another primary object of the present invention is to provide an improved keyless lithographic printing apparatus having greater latitude in the selection of useful metering roller technologies.

[0019]

SUMMARY OF THE INVENTION The foregoing objects are achieved by the present invention by providing an improved keyless printing apparatus for use in a keyless lithographic printing press having a blanket cylinder and a plate cylinder to which a printing plate is attached. be done. The improved keyless printing device includes a device for supplying dampening water to a press cylinder, at least one forming roller (foam roller) in rotational contact with the press cylinder, and an inking drum in rotational contact with the forming roller. and at least a first and a second inking drum in rotational contact with the inking drum.
a transfer roller and at least one oleophilic, hydrophobic surface that retains a quantity of printing fluid along with an ink modifying doctor blade for effecting the transfer by rotating contact with the first and second transfer rollers. and a device for supplying printing fluid to the metering roller. In a preferred embodiment, the first and second transfer rollers are frictionally driven by at least the metering roller and have a surface speed that is substantially the same as the surface speed of the metering roller.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The features of the invention that are considered novel are particularly defined in the claims. The present invention, together with further objects and advantages, is best understood by reference to the following description taken in conjunction with the accompanying drawings, in which like components indicate like elements.

A keyless ink applicator incorporating the present invention is shown in FIG.
Printing on a moving web is now possible, as shown here. First of all, this blanket cylinder 1
Referring to the dampening and inking device combined in FIG. and is in contact with the metering roller 20. Ink measuring roller 20
No. 4,862,799, 4,8
No. 82,990, No. 4,537,127, No. 4,56
Preferably, it is of the type disclosed in U.S. Pat. No. 7,827 or No. 4,601,242. The dampening device associated with the plate cylinder 15 typically uses a rubber dampening roller 19 and a vibrating transfer roller 22, which can be copper-coated or chrome-coated. The water is contained within a tray pan 23 from which a pan roller 24 is used to pick up water and contact it, for example, with a helical brush roller 25. is rotating at a speed relatively different from the rotation speed of the plate roller 24. It must be recognized that virtually any known dampening device may be used in the present invention.

[0022] By the arrangement described above or otherwise, the dampening solution is transferred onto the transfer roller 22 and from this transfer roller to the dampening forming roller 19. These forming rollers 19 are arranged so as to undergo sequential operation, usually first in contact with the water, and during each revolution of the press after transferring the ink to the blanket cylinder 10 these plates are exposed to renewed printing fluid. The rubber-coated printing fluid is first adapted to receive dampening solution from a dampening roller 19 before being applied by forming roller 16 to the imaging surfaces of these plates.

An important part of the invention is the inking device used to supply printing fluid to plate cylinder 15 and blanket cylinder 10. This device supplies the plate cylinder 15 with a homogeneous mixture of ink and naturally occurring dampening solution, thereby making it possible to retain the high print quality characteristics of conventional lithographic printing. In such an arrangement, the printing fluid application and circulation system is indicated generally at 30;
It is used to supply an ink-containing dampening solution, or printing fluid, to the metering roller 20. The dampening solution in this device is not carefully added to the ink, but rather comes naturally from the ink that is brought into contact with the dampening solution on the printing plate cylinder 15, and this dampening solution is not used or Alternatively, a return portion of the printing fluid that is returned through the various rollers eventually enters the printing fluid application device 30 in part.

The printing fluid applicator portion of the apparatus 30 of the present invention is shown in FIGS. 2 and 3 in an open solution position relative to the metering roller 20. An end view of this device engaged with metering roller 20 in the closed operating position is shown in FIG. Metering roller 20 has first and second ends 32 and 34 that rotate within frames 36 and 38, respectively. Metering roller 20 has a surface 40 intermediate its first and second ends 32 and 34.
, such that this surface 40 can hold a quantity of printing fluid. Housing 42 has an open first side 46 that mates with at least a portion of surface 40 of metering roller 20 . A chamber 44 containing printing fluid at a predetermined pressure is formed when the housing 42 is in the closed operating position.

At least first and second sealing assemblies 4
8 and 50 are attached to first and second ends 52 and 54 of housing 42, respectively. These first and second end seal assemblies 48 and 50 each have a first surface 56 that mates with the first and second ends 58 and 60, respectively, of metering roller 20.

Referring now to FIGS. 4 and 5, an inverted doctor blade 62 is mounted on the side 64 of housing 42 in FIG.
has an edge 66 that contacts the printing fluid fill chamber 44 to remove excess printing fluid adhering to the surface 40 as the metering roller 20 rotates past the printing fluid fill chamber 44 . Sealing member 6
8 is attached to the third side 70 of the housing 42 and has an area 72 that substantially seals the chamber 44 such that at least an area 72 of the sealing member 68 is attached to the surface 40 of the metering roller 20. Adjacent to the rim 74 of the sealing member 68 extends into the chamber 44 . In a preferred embodiment, the sealing member 68 is substantially longer than the reverse-angle doctor blade 62 and is made more flexible.

Since the printing fluid in chamber 44 is under pressure, this reverse-angle doctor blade 62 is held at least in part against face 40 of metering roller 20 by the pressurized printing fluid in chamber 44. This is a feature of the present invention.

It is known in the printing press art to vibrate selected rollers or cylinders (eg Goss Metroliner Parts Catalog No. 280-PC, Figure 280-56). Referring again to FIG. 1, in the present invention, such a vibration drive 76 is attached to the metering roller 20, thereby imparting vibrations to the metering roller 20 while the housing 42 of the printing fluid applicator 30 is stationary. It is now possible to give. The metering roller 20 is of the type having an oleophilic and hydrophobic surface.

Depending on the application, it may or may not be necessary to provide vibration to metering roller 20. However, it is a novel feature of the present invention that in applications where it is desirable to impart vibration to the metering roller 20, this can be done by the printing fluid application apparatus of the present invention.

For example, the sealing member 68 is formed of steel or plastic and has a diameter of approximately 2.54 to 2.5 mm, selected as a function of the dimensions of the first side of the housing 42 and the diameter of the metering roller 20 associated with this side. The sealing member 68 can have a width ranging from 1 to 2 inches and a thickness ranging from about 0.010 to 0.01 inches. This is done to properly seal the chamber 44. The reverse angle doctor blade 62 is formed of steel or plastic and typically has a width of about 2.54 cm (1 in) and a width of about 0.010 to 0.254 mm (0.254 mm) for steel.
004 to 0.01 inch), for plastics,
Approximately 1.016 to 1.524mm (0.04 to 0
．． 0.06 in.).

As shown in FIG. 6, the housing 42 is attached to a support blanket 80 which is pivotable about an axis 82 to provide an open utility position and a closed operating position. Housing 42 and metering roller 20 are shown in the open service position in FIGS. 2 and 3, with FIG. 2 being a plan view and FIG. 3 being an elevation view.

The printing fluid application device further includes a housing 4
2 includes within the housing 42 at least one inlet device 102 for introducing printing fluid into the chamber 44 and at least one outlet device 104 for exiting the printing fluid from the chamber 44. The chamber 44 contains the metering roller 20,
Sealed by first and second end seal assemblies 48 and 50, reverse angled doctor blade 62 and sealing member 68, the printing fluid can be maintained at a predetermined pressure. It will become. In the preferred embodiment, a circulation system is used to propel printing fluid through housing 42, as described below. Since the printing fluid is under pressure, the printing fluid circulation system is completely independent of the action of gravity, as opposed to prior art devices that rely on the printing fluid falling into a reservoir or catch pan. is an important feature of the present invention. Accordingly, the housing 42 can be placed anywhere around the metering roller 20. This is an extremely important advantage in the art of keyless lithographic printing press design. This allows the pair of printing devices of the press to be reversed, thereby shortening the length of the paper path between the pairs and saving space and material in the structure. The flexibility to position housing 42 anywhere around metering roller 20 provides a degree of freedom in printing press design not available in prior art keyless printing presses.

Furthermore, the housing 42 is connected to the metering roller 2.
0 can be designed to extend the entire axial length of the surface 40 or to extend only a portion of the surface 40. For example, multiple housings, each smaller than the overall width of the press, can be placed on one metering roller 20. Additionally, the housing 42 can be configured to be wrapped more or less around the metering roller 20 depending on the criteria of the press being designed.

Referring now to FIGS. 10 and 11,
Each end seal assembly 48 and 50 shown in FIGS. 2 and 3 includes a seal device 90 supported by a seal cap 92. As shown in FIGS. As shown in FIG. 5, a seal cap 92 is attached to one end of the housing 42, and more particularly, a seal cap assembly is attached to each end of the housing 42.

Additionally, the present invention may include a gauge assembly 94 as shown in FIGS. 7, 8 and 9, in which the housing 42 is connected to the metering roller 20 as shown in FIG. housing 42 relative to
The housing 42 is adapted to engage the locating pin 96 when pivoted to the closed operating position for precise positioning of the housing 42 . The gauge assembly 94 is located adjacent the first and second ends 32 and 34 of the metering roller 20. The gauge assembly 94 has first and second portions 81, 83 surrounding the ends 32, 34 of the metering roller 20.

Generally speaking, chamber 4 within housing 42
A device 100 for pressurizing 4 with a printing fluid is connected to the housing 42 via an inlet device 102 and an outlet device 104 of the housing 42 .

As shown in FIG. 12, this pressurizing device 1
00 is a pump 10 with an outlet 108 and an inlet 110
It is a circulation device having 6. Outlet 108 of pump 106
is connected to the pressure regulating check valve 111 and to the inlet device 102 of the housing 42. Inlet 11 of pump 106
0 is connected to printing fluid reservoir 112 which is also connected to outlet device 104 of housing 42 . Figure 1
As shown at 2, a pressure regulating check valve 111 is also connected to the printing fluid reservoir 112. In the preferred embodiment, the pump 106 is a constant speed drive motor 114 coupled to a press unit controller 116 of the printing press.
It is designed to be driven by The press unit controller 116 is also adapted to receive signals from a sensor 118 mounted within the housing 42 to sense the pressure of the printing fluid within the chamber 44 of the housing 42. In one embodiment, 0.28-0.4
A pressure of 2 kg/cm2 (4-6 psi) is maintained within chamber 44 to enable smooth and consistent application of printing fluid to metering roller 20. This pressure regulating check valve 111 has a pressure of 0.28-0.4 in the chamber 44.
It operates to establish a pressure of 4-6 psi to allow a portion of the printing fluid to flow back into the printing fluid reservoir 112 as needed.

FIG. 13 shows an alternative apparatus 100 for pressurizing the chamber 44 in which the pump 106 is driven by a motor 120 which is in turn connected via a variable speed drive 122. The press is operated at a speed proportional to the speed of the printing press. In this embodiment, outlet 1 of pump 106
08 is connected to an inlet device 102 of the housing 42 and an outlet device 104 of the housing 42 is connected to a printing fluid reservoir 112. The inlet 110 of this pump is connected to a printing fluid reservoir 112. Printing fluid reservoir 11 of the embodiment of FIG. 12 or 13 is filled with new refill ink as needed.
A variety of devices can be used to add 2. For example, the apparatus includes a solenoid valve 124 coupled to a press unit controller 126 such that the press unit controller 126 receives a signal from a printing fluid level sensor 128 coupled to the printing fluid reservoir 112. be able to. It is a novel feature of the present invention that printing fluid reservoir 112 can be positioned relative to chamber 44, either higher or lower than chamber 44. This is because the flow of printing fluid is regulated by the internal pressure of chamber 44 and not by gravity.

Furthermore, the present invention may include a device for controlling the temperature of the printing fluid within chamber 44 of housing 42. For example, a device for controlling this temperature can be connected directly to housing 42 or can be connected to printing fluid reservoir 112. The device for controlling this temperature is a resistive strip heater (e.g. Chromalox No. SL0515) mounted on the housing 42.
(No. 1, flexible resistance element heaters) can be used. For printing fluid reservoir 112, Chromalox No. AR
An immersion type heater such as MTO-2155T2 can be used.

The present invention overcomes many of the problems, difficulties and limitations of prior art keyless lithographic printing devices. For example, the prior art pan and pan roller cited above (U.S. Pat. No. 4,690,055)
can be replaced by a more compact, less complex housing which together with the face of the metering roller forms a complete enclosing housing.

The inks selected for use in the present invention have low viscosity values at low shear ratios, allowing the printing fluid to flow more easily compared to conventional lithographic printing inks. is desirable. Ink having such properties is deposited within a section or small gap in the plane of the rapidly rotating metering roller 20 as it moves past the pressurized, slowly circulating printing fluid in the chamber 44. It can easily flow in and flow out through a small gap in the plane of the metering roller 20 after being metered by the doctor blade as practiced here.

An important feature when using the low viscosity printing fluid according to the invention is that the ink can be tailored to have good printing fluid transfer properties in the inking roller train, yet has a wide range of viscosity values at low shear rates. It can have any value within a range, and such adjustments are related to the various roller and cylinder configurations used in a particular printing press. Such capability was not possible with prior art dish roller printing fluid application devices. This is because the amount of printing fluid applied to the metering roller is related to the force of the countersunk roller and not to the movability of the printing fluid. Such capability is also not possible without the use of oleophilic and hydrophobic metering rollers. This is because water is more easily separated from less viscous printing fluids, and without hydrophobic properties, the printing fluid would be stripped from the metering rollers, thereby defeating the control of ink application.

In FIGS. 14 to 16, paper strip 1
2. Blanket cylinder 10, plate cylinder 15, forming roller 16, dampening device 14 and oleophilic inking drum 11 are all arranged substantially parallel in the axial direction, more or less standard in the practice of lithographic printing. It has been made into a beautiful element. Conventionally, and as in common practice, only one transfer roller 13 transfers the metered ink by cooperating metering rollers 20 and blades 18 to the oleophilic inking drum 11 and from there to the forming roller 16 , the paper strip 1 by the printing plate cylinder 15 and the printing blanket cylinder 10
Required to transfer to 2. The present invention provides and requires a second transfer roller 17 in addition to the first transfer roller 13 for reasons explained below. . 14 to 16 illustrate embodiments of variations of the invention, which may include different ink or printing fluid application devices 30 and different moisturizers than those described above to demonstrate the flexibility of the invention. The structure is similar to that described above except that the arrangement of the device 14 is shown. The capacity of the printing fluid application and circulation system 30 is designed to be approximately 5 gallons less ink or printing fluid. Other combinations of inking and dampening devices can be readily devised by those skilled in the art based on the teachings described herein without departing from the general contemplation of the present invention.

Also, as shown in FIG. 14, an auxiliary transfer roller 213 can be used in rotational contact with the inking drum 11. This auxiliary transfer roller 213 is adapted to transfer printing fluid to the auxiliary inking drum 211 . A further auxiliary forming roller 216 is arranged in rotational contact with this auxiliary inking drum 211 and plate cylinder 15. Other variations of auxiliary rollers, drums and cylinders can be used in the present invention.

While implementing the keyless inking technique described in US Pat. No. 4,690,055,
When it becomes necessary to assemble a page-width keyless inker rather than a press-width inker, a prior art keyless inker with such separately driven countersunk rollers can be used. It turned out to be particularly difficult to configure. The center page of a four-width newspaper press is approximately 19.05 mm between the side-to-side page positions of a typical newspaper strip.
(3/4 inch) margin limits require that the two central countersunk rollers be mounted and coupled to separate drives.

US Pat. No. 4 with a Newspaper Press 4 Page Width
In implementing the teachings of No. 690,055, it is necessary to manufacture countersunk rollers of large weight and relatively large diameter in order to avoid deflection or deformation of the unsupported central portion. However, this also requires a larger size ink tray and reservoir assembly, which, along with a matching pump and hose, is required for the printing couple.
It occupies a significantly large area below the . moreover,
The minimum practical ink fluid level in the reservoir pan is 18
．． It produces a relatively large volume of working ink, from 5 to 10 gallons. This means that an inconveniently large volume of ink must be handled whenever an ink change is required.

Furthermore, US Pat. No. 4,690,05
When implementing the technique No. 5, for example, from 3.175 mm to 4.
Typical values of countersunk roller-to-metering roller contact pressure for flat sections up to 762 mm (1/8 inch to 3/16 inch) reduce metering roller life due to premature wear of the metering roller face coating. It was found that there is a possibility that this may occur. With regard to the harshness of the general printing conditions, U.S. Pat.
The metering roller technology of No. 827 and No. 4,601,242 has shown that the expected 40 million or more Without being able to make copies, it is not possible to meter ink effectively for only 5 to 20 million printed copies.

The above and other reasons motivate the present invention to develop the improved keyless inking device of the present invention, which was previously taught by US Pat. No. 4,690,055. It retains all the functional features necessary to carry out keyless inking of lithographic printing without difficulty.

FIG. 18 is generally shown in US Pat. No. 4,690,
055 shows the prior art roller shape technology. FIG. 19 is similar, but with dish roller 21 removed from contact with metering roller 20. Figure 20, Figure 21
and FIG. 22 does not have a countersunk roller, but the metering roller 20
A similar keyless press roller configuration is shown with an additional rider roller 29 in contact with the . However, FIG. 22 shows a pressing device with a second transfer roller 17 according to the invention. All elements 10, 12, 1
5, 16 and 11 have been kept the same in shape as in FIGS. 18 to 22, but these devices have been evaluated in terms of operational and printing possibilities. All of these provide good ink transfer to the substrate of the paper strip being printed. However, using only one transfer roller 13 and no countersunk roller 21, the configuration shown in FIGS. This resulted in a deterioration in the uniformity of the measurable optical density values during the printing run. This result of poor uniformity is due to the fact that the countersunk roller 2
19, which corresponds to the technique described in US Pat. No. 4,690,055, which provides promise by a purposeful gap between 1 and metering roller 20. US Pat. No. 4,690,055 teaches that interference between the pan and metering roller is desirable. The results described above appear to confirm this teaching. The results according to the present invention also demonstrate the performance of the prior art when the frictionally driven press speed rider rollers 29 of FIGS. It has been proven that the characteristics are not inferior. Some of these results are shown in Table 1.
is shown.

[0050]

[Table 1]

When the frictionally driven roller 17 as in FIG. 22 is assembled in contact with both the main inking drum 11 and the metering roller 20 and the same non-uniform mold as in FIG. 23 is used, printing The device closely approximates the advantages of prior art countersunk roller inking devices as taught by U.S. Pat. No. 3,998,546. The corresponding results are also listed in Table 1 above.

The frictionally driven press speed second transfer roller of the present invention avoids the need for intricate contact of the metering roller with any inking roller operating at a significantly different surface speed than the metering roller itself. That's what I do. In the present invention, the useful life of the previously described advantageous hard oleophilic hydrophobic inking roller is improved by the use of separately driven countersunk rollers, as disclosed in U.S. Pat.
They have found that when the technique of No. 1 is utilized, the increase can be increased by a factor of 2 to 10.

The reason for the advantageous more uniform optical density effect is clearly not known. Indeed, the variant of FIGS. 20 and 21 would be similar to FIG. It acts on Table 1 proves that this is not the case and that the two double contact transfer roller configurations shown in FIG. 22 are clearly superior.

Irrespective of the precise technical reason, the present invention provides that a slow-moving inking plate roller riding on a sectioned metering roller at prior art press speeds is effective when printing with a keyless lithographic printing press. It is shown that it is not the only form that provides the necessary processing capabilities to ensure minimal type dependence of optical density. Such slow-moving dish rollers can be replaced by transfer rollers at a second press speed as shown here, yet with even less printing fluid circulation, smaller dimensions of the overall inking device, This offers the advantage of less wear on the sectioned metering roller during printing operations and the opportunity to use any of several printing fluid application devices.

The invention is not limited to the particular details of the device described above, but contemplates other modifications and applications. Certain other modifications may be made to the above-described apparatus without departing from the true spirit and scope of the invention herein presented. Accordingly, the subject matter of the above description is intended to be illustrative only and not in a limiting sense.

Since the invention is constructed as described above, pans and pan rollers are omitted and at least two transfer rollers are used in the inking roller bank between the metering roller and the inking drum. by overcoming the problems, difficulties and inconveniences of the prior art, yet retaining all the principals important to keyless lithographic printing devices such as those described in U.S. Pat. No. 4,690,055. A superior keyless lithographic printing device is provided.

[Brief explanation of the drawing]

1 is a schematic side view of a keyless lithographic printing press apparatus according to the invention; FIG.

FIG. 2 is a plan view of the printing fluid application device and metering roller of the present invention.

FIG. 3 is an elevational view of the printing fluid applicator and metering roller of the present invention.

FIG. 4 is an end view of the printing fluid applicator and metering roller.

FIG. 5 is a partial plan view of the printing fluid application device.

FIG. 6 is an end view of the metering roller and printing fluid applicator in an open service position.

FIG. 7 is a plan view of a gauge assembly used in the present invention.

FIG. 8 is an elevational view of a gauge assembly used in the present invention.

FIG. 9 is a side view of a gauge assembly used in the present invention.

FIG. 10 is a plan view of a seal cap assembly used in the present invention.

FIG. 11 is an elevational view of a seal cap assembly used in the present invention.

FIG. 12 is a schematic circulation circuit diagram of a pressurized printing fluid circulation device used in the present invention.

FIG. 13 is a schematic circuit diagram of a modified pressurized printing fluid circulation device used in the present invention.

FIG. 14 is a schematic side view of a variant embodiment of the invention with a doctor blade and a retracted ink catcher pan.

FIG. 15 is a schematic side view of a variant embodiment of the invention with an injector or extrusion inking element;

FIG. 16 is a schematic side view of a variant embodiment of the invention with an inking shoe or rail element;

FIG. 17 is a schematic side view of an embodiment of the present invention having a doctor blade and a recirculating ink catcher pan with a single forming roller.

FIG. 18 is a schematic side view of a prior art device according to US Pat. No. 4,690,055.

FIG. 19 is a schematic side view showing an experimental configuration similar to that according to the aforementioned U.S. Pat. No. 4,690,055, but with a countersunk roller just out of recessed relation to the metering roller; figure.

FIG. 20 is a schematic side view of an experimental configuration with additional rider rollers.

FIG. 21 is a schematic side view of an experimental configuration with additional rider rollers.

FIG. 22 is a schematic side view of a preferred embodiment of the invention with two transfer rollers.

FIG. 23 shows the printed shape of a target plate used to test the configurations of FIGS. 18 to 22;

[Explanation of symbols]

10 Blanket cylinder 11 Lipophilic ink application drum 12 Paper strip 13 Transfer roller 14 Dampening device 15 Plate cylinder 16 Ink forming roller 17 Second transfer roller 18 Blade 19 Dampening forming roller 20 Metering roller 21 Disc roller 22 Vibrating transfer roller 24 countersink roller 25 helical brush roller 29 rider roller 30 printing fluid application and circulation system 36 frame 38 frame 40 printing fluid retaining surface 42 of metering roller 20 housing 44 printing fluid fill chamber under pressure 48 end seal assembly 50 end Part sealing assembly 62 Doctor blade 68 Sealing member 76 Vibration drive device 92 Sealing cap 94 Gauge assembly 96 Locating pin 100 Pressure device 106 Pump 111 Pressure regulating check valve 112 Printing fluid reservoir 114 Constant speed drive motor 116 Press - Unit controller 118 Sensor 120 Motor 122 Variable speed drive 124 Solenoid valve 126 Press unit controller 128 Printing fluid level sensor 211 Auxiliary inking drum 213 Auxiliary transfer roller 216 Auxiliary forming roller

Claims (20)

[Claims] 1. An improved keyless printing apparatus in a keyless lithographic printing press having a plate cylinder having a blanket cylinder and a printing plate attached thereto, comprising: a means for supplying dampening water to the plate cylinder; at least one forming roller in rotational contact, an inking drum in rotational contact with the forming roller, at least first and second transfer rollers in rotational contact with the inking drum, capable of holding a quantity of printing liquid; an improved metering roller having at least one oleophilic and hydrophobic surface and in rotational contact with the first and second transfer rollers; and a device for supplying printing fluid to the metering roller. Keyless printing device. 2. The improved keyless printing device of claim 1, wherein said first and second transfer rollers are frictionally driven by at least said metering roller. 3. When the metering roller rotates during a printing operation, the first and second transfer rollers rotate and have a surface speed that is substantially the same as a surface speed of the metering roller. An improved keyless printing device as claimed in claim 1. 4. The improved keyless printing of claim 1, wherein the device for supplying dampening water to the plate cylinder includes at least one dampening roller in rotational contact with the plate cylinder. Device. 5. The device for supplying dampening water to the plate cylinder includes at least one dampening roller in rotational contact with the inking drum, such that the inking roller transfers dampening water to the dampening drum. 2. The improved keyless printing device of claim 1, further comprising transfer from a printing roller through said foam roller to said plate cylinder. 6. The improved keyless printing apparatus of claim 1, wherein said printing fluid supply device is an underload ink fountain device that provides printing fluid to said metering roller. 7. The improved keyless printing device of claim 1, wherein the device for supplying printing fluid is an injector device for applying printing fluid to the metering roller. 8. The improved keyless printing apparatus of claim 1, wherein said printing fluid supply device is a slit manifold device that provides printing fluid to said metering roller. 9. The improved keyless printing apparatus of claim 1, wherein said printing fluid supply device is a pressurized printing fluid and circulation device that provides printing fluid to said metering roller. 10. An improved keyless printing fluid transfer device in a keyless lithographic printing press having at least one inking drum and a metering roller having an oleophilic and hydrophobic surface capable of holding a quantity of printing fluid, comprising: an improved key comprising a plurality of transfer rollers in rotational contact with the inking drum and the metering roller and transferring at least the printing liquid from the metering roller to the inking drum during operation of the printing press. No printing liquid transfer device. 11. The improved keyless printing device of claim 10, wherein said printing fluid transfer device includes first and second transfer rollers. 12. The improved keyless printing device of claim 10, wherein said plurality of transfer rollers are frictionally driven by at least said metering roller. 13. When the metering roller rotates during a printing operation, the plurality of transfer rollers are configured to rotate to have a surface speed that is substantially the same as a surface speed of the metering roller. An improved keyless printing device as described in . 14. An improved keyless printing apparatus in a keyless lithographic printing press having a plate cylinder having a blanket cylinder and a printing plate attached thereto, comprising: a means for supplying dampening water to the plate cylinder; at least one forming roller in rotational contact with the forming roller; an inking drum in rotational contact with the forming roller; and at least first and second transfer rollers in rotational contact with the inking drum; , at least 1
having two lipophilic and hydrophobic surfaces, said first and second
a metering roller adapted to be in rotational contact with a transfer roller, and a device for supplying printing liquid to the metering roller, the first and second transfer rollers being driven by at least the metering roller, the metering roller being driven by at least the metering roller; An improved keyless printing device adapted to have a surface speed substantially the same as the surface speed of the roller. 15. The improved keyless printing of claim 14, wherein the device for supplying dampening water to the plate cylinder includes at least one dampening roller in rotational contact with the plate cylinder. Device. 16. The improved keyless apparatus of claim 14, wherein the device for supplying dampening water to the plate cylinder includes at least one dampening roller in rotational contact with the inking drum. Printing device. 17. The improved keyless printing apparatus of claim 14, wherein said printing fluid supply device is an underload ink fountain device that provides printing fluid to said metering roller. 18. The improved keyless printing apparatus of claim 14, wherein the device for supplying printing fluid is an injector device for applying printing fluid to the metering roller. 19. The improved keyless printing apparatus of claim 14, wherein said printing fluid supply device is a slit manifold device that provides printing fluid to said metering roller. 20. The improved keyless printing apparatus of claim 14, wherein said printing fluid supply device is a pressurized printing fluid and circulation device for applying printing fluid to said metering roller.