JP2001162769A - Device for ink supply of printing press - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for ink supply of a printing press which prevents the amount of transfer of ink from becoming unstable, even when a difference in speed is present between a fountain roller and the subsequent roller and also which prevents the ink from moving to the lower part of a cylinder under its own weight when the rotation of the fountain roller stops and thus can prevent nonuniformity in the thickness of the ink in the circumferential direction. SOLUTION: Minute indentations 4a are formed in the surface of the fountain roller 4. The height (height from the bottom of the recess to the peak of the projection) (h) of the minute indentations 4a is set to be smaller than a minute gap (c) between the fountain roller 4 and the subsequent pickup roller. These minute indentations 4a of the fountain roller 4 increase sharply the area of contact of the ink with the surface of the fountain roller 4 in comparison with a smooth surface of a usual fountain roller and enhances the capacity of the surface of the fountain roller 4 to retain the ink.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of an ink supply device of a printing press for supplying ink to a plate surface on a plate cylinder, and in particular, receives ink first and applies the ink to a next roller. The invention belongs to the technical field of an ink supply device for a printing press having a fountain roller to be transferred.

[0002]

2. Description of the Related Art In a printing press such as an offset rotary printing press for newspaper printing, an ink supply device for supplying ink to a plate surface on a plate cylinder is provided with a fountain roller. Upon receiving the ink, the ink is transferred to the next supply roller. The ink supply method in the conventional ink supply device is
It is classified into an ink rail system and a pot system.

FIG. 5 is a view schematically showing an example of a conventional ink supply apparatus using an ink rail system. In the figure, 1 is an ink supply device of a printing press, 2 is a pump, 3 is an ink rail, 4 is a fountain roller (corresponding to the first roller of the present invention), and 5 is a pickup roller (corresponding to the second roller of the present invention). , 6 is a rubber roller, 7 is an ink drum, 8 is a rubber roller, 9 is an ink drum, 10 is an ink application roller,
Numeral 11 denotes a plate cylinder, numeral 12 denotes a wet roller, and numeral 13 denotes a blanket cylinder.

As shown in FIG. 5, in the ink supply system 1 of the ink rail type, ink sent out by a pump or the like is discharged from an orifice (not shown) of the ink rail 3 by an appropriate amount of ink, and the ink rail 3 is attached to the surface of the fountain roller 4 which is in close proximity with a small gap. Next, the ink adhered to the surface of the fountain roller 4 is scraped off by an appropriate amount by the pickup roller 5 which is in close proximity to the fountain roller 4 with a small gap, and is transferred to the surface of the pickup roller 5. The ink is transferred to a pair of ink applying rollers 10 and 10 via an ink drum 7, a rubber roller 8 and an ink drum 9. Further, ink is supplied from these ink forming rollers 10 and 10 to a plate surface of a printing plate (not shown) mounted on the surface of the plate cylinder 11. At this time, the ink is transferred by a roller group including a large number of rollers from the fountain roller 2 to the ink setting rollers 10, 10, so that the ink is sufficiently kneaded and formed into a uniform thin film, and the plate cylinder is formed. 11
Will be supplied to the plate. In addition, wetting roller 1
From 2, dampening water is supplied to the non-image forming portion of the plate surface of the plate cylinder 11 so that ink is not supplied to this non-image forming portion. Then, the ink image formed by the ink supplied to the plate surface of the plate cylinder 11 is transferred to the blanket cylinder 13, and the transferred image is printed on a printing paper (not shown).

The surface speed of the fountain roller 4 is set at the same speed as the running speed of the printing paper, is set at a speed proportional to the running speed of the printing paper, or is independent of the running speed of the printing paper. It is set to a constant speed. In any of these cases, since the ink rail 3 is fixed and stopped, a speed difference exists between the ink rail 3 and the fountain roller 4. In general, the surface speed of the fountain roller 4 is often set lower than the surface speed of the next pickup roller 5 which is set to the same speed as the running speed of the printing paper. It is often set smaller. Therefore, there is also a speed difference between the surface speeds of the fountain roller 4 and the pickup roller 5.

As described above, if there is a speed difference between the fountain roller 4 and the ink rail 3 and between the fountain roller 4 and the pickup roller 5, the surface of the fountain roller 4 is damaged by the speed difference. In order to avoid damage due to the speed difference, the distance between the fountain roller 4 and the ink rail 3 and the distance between the fountain roller 4 and the pickup roller 5 are reduced.
And a predetermined value (usually, 10
A minute gap of about 0 μm (but not limited to this) is provided (only the gap c between the rollers 4 and 5 is shown in FIG. 5).

FIG. 6 is a diagram schematically showing an example of a conventional ink supply device using a pot. In the drawing, reference numeral 14 denotes a pot for storing ink. In addition, the same reference numerals are given to the components corresponding to the components of the above-described ink rail type ink supply device. As shown in FIG. 6, in the ink supply device 1 of the fountain type, a part of the surface of the fountain roller 4 is immersed in the fountain 14 storing the ink, and in this state, the fountain roller 4 is moved up to 15 to 20 per minute. Rotated by rotation. Then, ink adheres to the surface of the fountain roller 4 and, among the adhered ink, excess ink is scraped off by a blade (not shown), so that an appropriate amount of ink is fed to the pickup roller 5, It is scraped off by the pickup roller and transferred to the surface of the pickup roller. Although not shown, the ink transferred to the pickup roller 5 is supplied to the surface of the plate attached to the plate cylinder 11 through a predetermined number of rollers similarly to the case of the ink rail system described above. Also, in the ink supply device 1 of the fountain type, a predetermined minute gap c is provided between the fountain roller 4 and the pickup roller 5 in order to avoid damage due to a speed difference as in the case of the ink rail type described above. Have been.

In any of these ink supply systems, the surface of the conventional fountain roller 4 is
The surface of the fountain roller 4 which is required to be changed every time the ink is changed is made a smooth surface so as to facilitate cleaning, and the ink is adhered and held on the smooth surface. On the other hand, the pickup roller 5 is generally provided with oblique streaks having a predetermined angle with respect to the axial direction of the pickup roller 5, or the oblique streaks are used to facilitate scraping of ink. Are formed so as to intersect with each other.

[0009]

However, if there is a speed difference and a gap between the ink rail 3 and the fountain roller 4 as described above, ink drips from the ink rail 4. The speed difference and the gap c between the fountain roller 4 and the next pickup roller 5
Is present, the ink adhering to the surface of the fountain roller 4 is affected by changes in the machine speed, ink tack, water content of the ink, and the like, so that the amount of ink transfer becomes unstable.

For example, as shown in FIG. 7, a predetermined amount of ink on the surface of the fountain
After the transfer, the filament α of the ink due to stringing is generated between the remaining ink on the surface of the fountain roller 4 and the ink transferred to the pickup roller 5. This filament α is applied to the fountain roller 4
As the ink on the pick-up roller 5 and ink on the pick-up roller 5 are separated, the ink is stretched and gradually thinned, and finally cut at several places, and a part of the ink mist β does not adhere to either of the rollers 4 and 5. Both rollers 4,5
Will be released from Therefore, the fountain roller 4
The transfer of the ink to the pickup roller 5 from the ink is hindered. Also, for example, during printing, dampening water or paper powder will be mixed into the ink adhering to the surface of the ink roller, but if the dampening water mixes with the ink, the transfer of the ink becomes unstable. Also, if an oxidized film is formed on the surface of the ink drum by the dampening solution, proper transfer of the ink is hindered. Further, the ink attached to the smooth surface of the cylindrical fountain roller 4 moves to the lower part of the cylinder by its own weight when the rotation of the fountain roller 4 is stopped, so that the ink thickness becomes uneven in the circumferential direction. There is also a problem.

Furthermore, compared to the ink film thickness transferred to the final printing paper, the fountain roller 4 needs to be supplied with an extremely large amount of ink from an ink rail or a fountain. Now, when printing with a predetermined ink film thickness on printing paper (running paper) in a state where there is a circumferential speed difference (peripheral speed) between the fountain roller 4 and the pickup roller 5 and a gap is provided. First, an approximate film thickness of the ink that must be formed on the surface of the fountain roller 4 will be obtained.

First, the ink film thickness on the fountain roller 4 and the pickup roller 5 is determined. As shown in FIG. 7, the ink film thickness of the fountain roller 4 before the nip (contact portion: ink transfer portion) with the pickup roller 5 is set to tf.
_1. The ink film thickness after the nip of the fountain roller 4 is t
f ₂ , the ink film thickness before the nip of the pickup roller 5 with the fountain roller 4 is tp ₁ , the ink film thickness after the nip of the pickup roller 5 is tp ₂ , the peripheral speed Sf of the fountain roller 4 (= the diameter of the fountain roller 4). × π ×
Rotation speed) and the peripheral speed Sp of the pickup roller 5 (= printing paper speed),

## EQU1 ## (tf ₁ −tf ₂ ) · Sf = (tp ₂ −tp ₁ ) · Sp.

(Tf ₁ −tf ₂ ) / (tp ₂ −tp ₁ ) = Sp / Sf Further, when tf ₁ is obtained,

## EQU3 ## tf ₁ = (Sp / Sf)） (tp ₂ -tp ₁ ) + tf ₂

Since a gap is provided between the fountain roller 4 and the pickup roller 5, a shear flow region of the ink is formed in the gap. In the shear flow region of the ink, a speed gradient occurs due to the ink pressure for ink transfer and the difference between the peripheral speeds of the rollers 4 and 5 from the surface of the pickup roller 5 to the surface of the fountain roller 4. As shown in FIG. 7, the shear failure of the ink layer occurs at the position where the speed difference is greatest, and one of the sheared ink layers is placed on the ink layer having the film thickness tp _{1 on} the surface of the pickup roller 5. Added as a layer. Then, the added ink layer having the film thickness tp becomes the ink transfer amount to the pickup roller 5. This ink transfer amount is mainly caused by a speed difference between the fountain roller 4 and the pickup roller 5. If the speed difference is large, the amount of ink transferred to the pickup roller 5 is small. The transfer amount of the ink increases. Therefore, it is necessary to consider the gap where the shear flow region of the ink is formed.

Referring now to FIG. 7, the fountain roller 4
Assuming that a gap between the roller and the pickup roller 5 is c, the ink in the gap c is sheared and broken, so that an ink layer having a film thickness tf ₂ is formed on the fountain roller 4 and a film thickness tp ₂ is formed on the pickup roller 5. Because the ink layer of is formed

## EQU4 ## tf ₂ + tp ₂ = c Therefore, from Equations 3 and 4,

## EQU5 ## tf ₁ = (Sp / Sf) · (tp ₂ −tp ₁ ) +
(C-tp ₂ )

## EQU6 ## tf ₂ = c-tp ₂

Next, the ink film thickness of the n rollers in a state where there is no circumferential speed difference and no gap is provided between two adjacent rollers is obtained. For simplicity of calculation, among the n rollers R ₁ ~Rn 8, the thickness of the ink on the two adjacent rollers each other is another nip roller, to each other after each nip Assume equal. For example, assuming that the film thickness of the ink on the _two rollers R ₁ and R ₂ is a and 3a before the nip, respectively, the film thickness of the ink after the nip on each of the rollers R ₁ and R ₂ is 2a. It is assumed that the thickness is half of the sum of the ink film thicknesses a and 3a on the rollers R ₁ and R ₂ . Also, for the sake of simplicity of calculation, it is assumed that each of the rollers R _{1 to} Rn is in contact (nip) on a one-to-one basis (that is, one roller receives ink at one location).

As shown in FIG. 8, ink film thickness on printing paper
Let a be the nip np on the printing paper and ink transfer side.
₁First roller R₁Nip with printing paper in₁Previous
Is 2a. Also, the first roller R₁
Ink receiving side and nip np_TwoSecond roller R_TwoSmell
First roller R₁Nip np with_TwoThe previous ink film thickness is 3a
Becomes Further, the second roller R_TwoInk receiving side and nip
np_ThreeThird roller R _ThreeSecond roller R at_TwoAnd d
Np_ThreeThe previous ink film thickness is 4a. Similarly,
(N-1) roller R_n-1Ink receiving side and nip np_n
Nth roller R _n(N-1) roller R_n-1With
Nip np_nThe previous ink film thickness is (n + 1) · a.
At this time, the n-th roller R_n(N-1) roller R
_n-1Nip np with_nThe subsequent ink film thickness is na. I
Also, the n-th roller R_nInk from the fountain roller
As a pickup roller to receive, tp₁= Na
And tp_Two= (N + 1) · a, and (tp_Two−
tp₁) = A. Therefore, the above Equation 5 becomes

Tf ₁ = {(Sp / Sf)-(n + 1)} · a + c

Therefore, as a specific example, a trial calculation of the ink film thickness tf ₁ before the nip of the fountain roller 4 with the pickup roller 5 in the ink supply device shown in FIG. Specific values of the respective values are as follows. Ink film thickness on printing paper aa = 0.8 μm Nip number n = 8 Printing paper speed v = 43.6 km / h Gap between fountain roller 4 and pickup roller 5 c = 100 μm Pickup Peripheral speed of roller 5 Sp = 728 m / min Peripheral speed of fountain roller 4 In case of ink rail type Sfi = 33 m / min In case of crucible type If Sfo = 10 m / min, Sp / Sfi ≒ 22 and Sp / Sfo ≒ 73 , Tp ₁ = a · n = 6.4 μm, and tp ₂ = a · (n + 1) = 7.2 μm. Therefore, from Equation 7, tf _1i = (22−9) · 0.8 + 100 = 11.4 μm in the case of the ink rail type and tf _1o = (73−9) · 0.8 + 100 = 151.2 μm in the case of the pot type. Become. Similarly, the pickup roller 5 of the fountain roller 4 in the ink supply device shown in FIG.
Looking specifically estimate the ink film thickness tf ₂ after the nip with a same for pot-type case from Equation 6 of the ink _{rail, tf 2i = tf 2o = 100-7.2} = 92.8 μm.

From these estimated values, the film thickness tf ₁ on the fountain roller 4 before the nip, that is, when the ink is supplied from the ink rail or the fountain onto the fountain roller 4, is 110.4 μm or 151.2 μm, It can be seen that the ink film thickness is orders of magnitude greater than the required ink film thickness of 0.8 μm for the printing paper. That is, a very large amount of ink needs to be supplied to the fountain roller 4 from the supply ink rail or the fountain, and the fountain roller 4 must be able to reliably hold a large amount of ink. Therefore, not only the amount of ink transferred to the pickup roller 5 becomes more unstable, but also the ink film thickness becomes more non-uniform in the circumferential direction.

In addition, as shown in FIG. 7, when the ink is sheared and broken, a filament α is generated due to the stringing of the ink, and the filament α is partially removed as the surfaces of the fountain roller 4 and the pickup roller 5 are separated. Is cut off, and a free ink mist β which is not held by any of the fountain roller 4 and the pickup roller 5 is generated. When the ink mist β is generated, the amount of ink transferred to the pickup roller 5 becomes further unstable.

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and has as its object a first roller which receives ink from a first roller and a second roller which receives ink from the first roller. Even if there is a speed difference and a gap, the first roller can surely hold a large amount of ink, can suppress the ink transfer amount from becoming unstable, and moreover, when the rotation of the first roller is stopped, It is an object of the present invention to provide an ink supply device for a printing press, which can prevent the ink thickness in the circumferential direction from becoming uneven by suppressing movement to the lower portion of the cylinder due to its own weight.

[0021]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the invention of claim 1 includes a roller group including a predetermined number of ink supply rollers, and supplies ink to the plate cylinder by the roller group. In the ink supply device for a printing press, the roller group is provided with at least a first roller to which ink is first supplied, and a predetermined gap with respect to the first roller. A second roller for receiving ink from one roller, and an ink holding surface increasing means for increasing the contact area with the ink and increasing the ink holding force on the ink adhering surface of the first roller. Features.

Further, the invention according to claim 2 is characterized in that the means for increasing the ink holding force comprises fine irregularities. Further, the invention according to claim 3 is characterized in that the ink holding force increasing means comprises a predetermined number of protruding linear members having soft elasticity.

[0023]

In the ink supply device for a printing press according to the present invention, the ink holding force of the first roller is increased by the ink holding force increasing means provided on the ink adhering surface of the first roller. Therefore, when the ink supply device is of the ink rail type, the ink in the minute gap between the ink rail and the first roller is more strongly held by the first roller in front of the first roller than in the related art. . Therefore, after the ink is transferred from the ink rail to the first roller, the amount of ink remaining on the surface of the ink rail is relatively small. Accordingly, even if there is a speed difference between the ink rail and the first roller, ink dripping from the ink rail is reduced.

In addition, in both cases where the ink supply device is of the ink rail type or the fountain type, when the second roller scrapes ink from the first roller, the ink holding force of the first roller is increased. Separation of ink occurs between the surface of the first roller and the ink layer, and a phenomenon in which a large amount of ink is transferred to the second roller is suppressed. Accordingly, even if there is a speed difference between the first roller and the second roller, the amount of ink transferred from the first roller to the second roller becomes more stable. Further, since the ink holding force of the first roller is increased, when the rotation of the first roller is stopped, the ink on the cylindrical surface of the first roller is less likely to move to the lower part of the cylinder due to its own weight, and the ink thickness is reduced along the circumference. More uniform.

In particular, in the second aspect of the present invention, the means for increasing the ink holding force is constituted by fine irregularities. Thus, the first roller can be easily and inexpensively formed even if the ink holding force increasing means is provided. In the invention according to claim 3, the ink holding force increasing means is constituted by a predetermined number of protruding linear members having soft elasticity. These protruding linear members further increase the ink holding force, so that the aforementioned ink dripping is further reduced, the amount of ink transferred to the second roller is further stabilized, and the first roller The ink thickness becomes more uniform along the circumference.

[0026]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a partial cross-sectional view of a fountain roller used in an example of an embodiment of an ink supply device for a printing press according to the present invention. The same components as those of the above-described conventional ink supply device are denoted by the same reference numerals, and detailed description thereof will be omitted (the same applies to all the following examples).

In the ink supply device 1 of the printing press according to this embodiment, the pickup roller 5 is knurled to facilitate the scraping of the ink on the fountain roller 4 as in the prior art, though not shown. Fine irregularities are formed on the surface. As shown in FIG. 1, fine irregularities 4 a are also newly formed on the surface of the fountain roller 4. The height h (height from the bottom of the concave portion to the tip of the convex portion) h of these fine irregularities 4 a is set smaller than the minute gap c between the fountain roller 4 and the pickup roller 5. The fine unevenness 4a of the fountain roller 4 greatly increases the contact area between the ink and the surface of the fountain roller 4 as compared with the smooth surface of the conventional fountain roller 4 and increases the ink holding force on the surface of the fountain roller 4. Is increasing. That is,
The fine irregularities 4a constitute the ink holding force increasing means of the present invention. Other configurations of the ink supply device 1 of the printing press of this example are the same as those of the ink rail type ink supply device shown in FIG. 5 or the pot type ink supply device shown in FIG.

As described above, in the ink supply device 1 of the printing press of this embodiment, for example, in the case of the ink rail type, the fine unevenness 4a is formed on the surface of the fountain roller 4, and the ink holding force of the fountain roller 4 is reduced. Since the height is increased, the ink in the minute gap between the ink rail 3 and the fountain roller 4 is more strongly held by the fountain roller 4 in front of the fountain roller 4 than before. . Therefore, ink is transferred from the ink rail 3 to the fountain roller 4.
After being delivered to the ink rail 3, the amount of ink remaining on the surface of the ink rail 3 becomes relatively small. Thus, even if there is a speed difference between the ink rail 3 and the fountain roller 4, ink dripping from the ink rail 3 is reduced.

In both the ink rail type and the fountain type ink supply device 1, when the pickup roller 5 scrapes ink from the fountain roller 4 between the fountain roller 4 and the pickup roller 5, When the ink holding power of the fountain roller 4 is increased, the ink is separated between the surface of the fountain roller 4 and the ink layer, and the phenomenon that a large amount of ink is transferred to the pickup roller 5 is suppressed. Thereby, even if there is a speed difference between the fountain roller 4 and the pickup roller 5, the amount of ink transferred from the fountain roller 4 to the pickup roller 5 becomes more stable. Further, since the ink holding force of the fountain roller 4 is increased, when the rotation of the fountain roller 4 is stopped, the ink on the cylindrical surface of the fountain roller 4 becomes difficult to move to the lower part of the cylinder due to its own weight, and the ink thickness increases along the circumference. More uniform.

FIG. 2 is a partial sectional view similar to FIG. 1, partially showing a fountain roller according to another embodiment of the present invention. In the example shown in FIG. 1 described above, the fountain roller 4 has fine unevenness 4a formed of a metal material as an ink holding force increasing means, but the fountain roller 4 of the ink supply device 1 of this example has a surface. And fine irregularities 4a made of rubber as means for increasing ink holding force.
have. Another configuration of the ink supply device 1 of this example,
The operation and effect are substantially the same as those of the above-described example.

FIG. 3 is a partial sectional view similar to FIG. 1, partially showing a fountain roller in still another example of the embodiment of the present invention. In each of the examples shown in FIGS. 1 and 2 described above, the fine unevenness 4a is formed on the surface of the fountain roller 4, but the fountain roller 4 of the ink supply device 1 of this example has It has a large number of protruding linear members 4b having soft elasticity, which are fibrous fluffs, as holding force increasing means. The length α of these fibrous protruding linear members 4b is larger than the gap c between the fountain roller 4 and the pickup roller 5, and is preferably about 1.5 times or less the gap c. These fibrous protruding linear members 4b greatly increase the ink contact area on the surface of the fountain roller 4 by greatly increasing the contact area with ink as compared with the related art, and constitute the ink retaining force increasing means of the present invention. are doing.

In the ink supply device 1 of the printing press of this example, when the fountain roller 4 rotates and ink adheres to the surface from the ink rail 3 or the fountain 14,
Since this ink is adhered and held by a number of projecting linear members 4b, the ink holding force of the fountain roller 4 is increased. At this time, as shown in FIG.
b lies in the direction opposite to the rotation direction of the fountain roller 4. In this state, when the ink layer having the thickness tf _{1 on} the surface of the fountain roller 4 moves toward the pickup roller 5, the ink layer having the thickness tp ₁ before the nip adhering to the surface of the pickup roller 5 is removed. After mixing, the inks of both ink layers move rightward in FIG. 4A while mixing.

As described above, a shear flow region of the ink is formed in the gap c between the fountain roller 4 and the pickup roller 5, and in the shear flow region of the ink, the ink pressure and the ink pressure for the ink transfer are reduced. In addition, a speed gradient occurs from the surface of the pickup roller 5 to the surface of the fountain roller 4 and the difference between the peripheral speeds of the rollers 4,5. Occur shear failure of the ink layer at the greatest at this speed difference, one of the ink layer which has been sheared is adhered to the surface of the pickup roller 5, the ink film thickness film thickness tp is plus film thickness tp ₁ with film The thickness is tp ₂ . Sheared other ink layer adheres to the surface of the fountain roller 4, the ink film thickness becomes the thickness tf _2.

When the ink layer is sheared and broken into two ink layers on the fountain roller 4 side and the pickup roller 5 side, a filament α is generated by the stringing of the ink as described above. As shown in FIG. 4B, the filament α is adhered and held by the protruding linear member 4, and is gradually expanded as the ink layers on the fountain roller 4 side and the pickup roller 5 side are separated.
And, finally filaments alpha is off, so divided into held in the protruding linear member 4 the fountain roller 4 side filament alpha ₁ and the pickup roller 5 side filaments alpha _2. At this time, since the protruding linear member 4 is formed relatively long, the fountain roller 4 side filament α ₁ held by the protruding linear member 4 occupies most of the generated filament α, and the pickup roller 5 side filament α ₂ is small. Moreover, since most of the filament α is held by the protruding linear member 4 with a relatively strong holding force, the ink mist β as shown in FIG. 7 described above hardly occurs.

Thus, when the pickup roller 5 scrapes ink from the fountain roller 4, the ink is separated between the surface of the fountain roller 4 and the ink layer, and a large amount of ink is transferred to the pickup roller 5. Is more effectively suppressed. Therefore, the fountain roller 4 can hold a large amount of ink, and there is also a peripheral speed difference and a gap c between the fountain roller 4 and the pickup roller 5, and the fountain roller 4 holds a large amount of ink. Even so, the amount of ink transferred from the fountain roller 4 to the pickup roller 5 becomes more stable.

Further, since the ink retaining force of the fountain roller 4 is further increased by the protruding linear member 4,
When the rotation of the fountain roller 4 is stopped, the ink on the surface of the cylinder of the fountain roller 4 hardly moves to the lower part of the cylinder by its own weight, and the ink thickness becomes more uniform along the circumference. Other configurations, functions, and effects of the ink supply device 1 of this example are substantially the same as those of the above-described examples.

In the above-described example, the present invention has been described as applied to the ink supply system of the ink rail system shown in FIG. 5 or the ink supply system of the fountain system shown in FIG.
The present invention can be applied to any ink supply apparatus provided with a fountain roller and a pickup roller, and having a peripheral speed difference and a gap between these two rollers.

[0038]

As is apparent from the above description, according to the ink supply device of the printing press of the present invention, the ink is first applied to the ink-applied surface of the first roller which receives the ink and transfers the ink to the second roller. Since the ink holding force increasing means for increasing the contact area with the ink to increase the ink holding force is provided, the ink holding force on the surface of the first roller can be increased. Therefore, when the ink supply device is of the ink rail type, the ink can be reliably transferred from the ink rail to the first roller, and the ink remaining on the surface of the ink rail can be relatively reduced. This allows
Even if there is a speed difference between the ink rail and the first roller, it is possible to reduce ink dripping from the ink rail.

Further, in either case of the ink rail system or the fountain system, the second roller scrapes ink from the first roller because the ink holding force of the first roller is increased. At this time, it is possible to suppress the phenomenon that a large amount of ink is transferred to the second roller by causing the ink to peel off between the surface of the first roller and the ink layer.
Thus, even if there is a speed difference between the first roller and the second roller, the amount of ink transferred from the first roller to the second roller can be further stabilized. Further, since the ink retaining force of the first roller is increased, it is possible to make it difficult for the ink on the cylindrical surface of the first roller to move to the lower part of the cylinder by its own weight when the rotation of the first roller is stopped. Thereby, the ink thickness can be maintained more uniformly along the circumference.

In particular, according to the second aspect of the present invention, since the ink holding force increasing means is constituted by fine irregularities,
Even if the ink holding force increasing means is provided, the first roller can be simply and inexpensively formed. According to the third aspect of the present invention, since the ink holding force increasing means is constituted by a predetermined number of protruding linear members having soft elasticity, these protruding linear members further increase the ink holding force. Can be strengthened. Therefore, the aforementioned ink dripping can be further reduced, the amount of ink transferred to the second roller can be more effectively stabilized, and the ink thickness of the first roller can be reduced along the circumference. Can be more uniform.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a fountain roller used in an example of an embodiment of an ink supply device for a printing press according to the present invention.

FIG. 2 is a partial cross-sectional view of a fountain roller used in another example of the embodiment of the ink supply device of the printing press according to the present invention.

FIG. 3 is a partial cross-sectional view of a fountain roller used in still another example of the embodiment of the ink supply device for a printing press according to the present invention.

FIG. 4 is a partial cross-sectional view illustrating ink transfer between a fountain roller and a pickup roller in the example shown in FIG. 3;

FIG. 5 is a diagram schematically illustrating an ink rail type ink supply device of a conventional printing press.

FIG. 6 is a diagram schematically illustrating a part of a fountain type ink supply device of a conventional printing press.

FIG. 7 is a diagram illustrating ink transfer between a fountain roller and a pickup roller in a conventional ink supply device.

FIG. 8 is a diagram schematically illustrating a roller group including n rollers used for calculating an ink film thickness.

FIG. 9 is a diagram schematically illustrating a roller group including nine rollers used for specific trial calculation of an ink film thickness.

[Explanation of symbols]

1. Ink supply device 2. Pump 3. Ink rail
4 Fountain roller (first roller), 4a ... fine irregularities, 4b ... fibrous protruding linear member, 5 ... pickup roller (second roller), 6, 8 ... rubber roller, 7, 9 ... ink drum, 10 ... Ink roller, 11 ... plate cylinder, 12
... watering roller, 13 ... blanket cylinder, 14 ... pot,
c ... gap

Claims (3)

[Claims] 1. An ink supply device for a printing press, comprising a roller group consisting of a predetermined number of ink supply rollers, wherein said roller group supplies ink to a plate cylinder. A first roller to which ink is supplied; and a second roller which is disposed with a predetermined gap from the first roller and receives ink from the first roller. An ink supply device for a printing press, wherein an ink holding force increasing means for increasing a contact area with ink to increase ink holding force is provided on a surface. 2. An ink supply device for a printing press according to claim 1, wherein said ink holding force increasing means comprises fine irregularities. 3. The ink supply device for a printing press according to claim 1, wherein said ink holding force increasing means comprises a predetermined number of projecting linear members having soft elasticity.