JPH0466189B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an ink supply method for a printing press equipped with a rotating plate cylinder, and more specifically, for a printing press equipped with a rotating plate cylinder such as a rotary printing press. The present invention relates to an improvement in an ink supply method for supplying ink from an ink fountain roller to an ink transfer roller.

[Prior Art] Conventionally, a doctor blade is pressed against a rotating ink fountain roller, and ink from an ink reservoir on the doctor blade is supplied to the circumferential surface of the ink fountain roller to form a desired thickness on the ink fountain roller. A thin ink film is formed on the ink fountain roller, and the ink thin film is brought into contact with an ink transfer roller (for example, a plate cylinder, a mixing roller, etc.), and ink is supplied to the ink transfer roller. A method of supplying ink to a printing press is known.

With this method, the thickness of the ink thin film can be adjusted arbitrarily by changing the pressing force of the doctor blade. Such an ink supply method has the excellent advantage that the size of the entire ink supply apparatus can be made compact.

[Problems to be Solved by the Invention] However, with this ink supply method, ink drips occur near the ink fountain roller on the lower surface (back side) of the doctor blade during operation, grows and becomes larger over time, and eventually There was a problem that the ink droplets fell onto the plate cylinder, damaging printed matter and staining the inside of the printing device.

In addition, to prevent this, the printing press must be stopped before the ink drips grow, and the grown ink drips must be manually cleaned up, which is a complicated process and results in excessive human body stains, and also reduces production. There was also the problem of decreased sex.

SUMMARY OF THE INVENTION An object of the present invention is to provide an ink supply method for a printing press that is easy to operate and shortens the down time of the apparatus, by improving the problems of the prior art described above.

[Means for Solving the Problems] In order to achieve the above object, the present invention has the following configuration.

That is, a doctor blade is pressed against a rotating ink fountain roller, and the ink in the ink reservoir on the doctor blade is supplied to the circumferential surface of the ink fountain roller to form an ink thin film of a desired thickness on the ink fountain roller. In the ink supply method for a printing press, the ink thin film is brought into contact with the ink transfer roller which is mounted on the ink fountain roller to supply ink to the ink transfer roller, comprising: A. the ink fountain roller; After separating the ink transfer roller and stopping the supply of ink from the ink fountain roller to the ink transfer roller, B. Stopping the rotation of the ink fountain roller for a certain period of time, and The ink dripping on the lower surface of the blade is transferred to the ink fountain roller, and after the above-mentioned certain period of time has elapsed, the ink fountain roller is rotated, and the dripping ink transfer portion is moved over the ink transfer roller which is being moved away. After passing through the ink fountain at least once, the ink fountain roller and the ink transfer roller are placed on the cylinder, and the supply of ink from the ink fountain roller to the ink transfer roller is started. The gist is the method.

Here, the ink fountain roller is an ink supply roller against which a doctor blade is pressed.

The ink transfer roller refers to a roller that collectively includes a plate cylinder and a kneading roller, and is a roller that is attached to the ink fountain roller. Note that the kneading roller is a roller interposed between the ink fountain roller and the plate cylinder.

The printing machine may be any known printing machine equipped with an ink fountain roller and an ink transfer roller.

Next, the present invention will be explained in detail based on the drawings.

FIG. 1 is a sectional view of an apparatus to which the present invention is applied.

In FIG. 1, 1 is an ink fountain roller;
A doctor blade 2 is pressed against the circumferential surface of the ink fountain roller 1 and the ink fountain roller 1 is rotated in the direction of arrow 6 to shear the ink 5 and form an ink thin film 7 on the circumferential surface of the ink fountain roller 1. do.

Here, the stronger the pressing force of the doctor blade 2, the thinner the ink thin film 7 becomes. The upper part of the ink fountain roller 1 and doctor blade 2 serves as an ink reservoir 4 in which ink 5 is stored.

The thin ink film 7 formed on the circumferential surface of the ink fountain roller 1 is transferred and supplied to an ink transfer roller 8 which is mounted on the ink fountain roller 1.

The ink supplied to the ink transfer roller 8 is not the entire thin ink film 7 formed on the ink fountain roller 1, but only the necessary portion of the ink is supplied to the ink transfer roller 8. Therefore, after ink has been supplied to the ink transfer roller 8, a considerable amount of ink remains on the surface of the ink fountain roller 1, and the ink is replenished in the ink fountain 4, and a new ink thin film 7 is formed by the doctor blade 2. This operation is performed continuously during printing.

FIGS. 3 to 5 are explanatory diagrams showing over time the process in which ink dripping on the lower surface of the doctor blade near the ink fountain roller (hereinafter referred to as an ink dripping portion) is generated and grows.

FIG. 3 shows a state in which a small ink drip portion 9 is formed on the lower surface of the doctor blade 2 during operation of the printing press. As time passes, the ink drips into a large ink dripping portion 9' as shown in FIG. 4, and is on the verge of falling onto the ink transfer roller 8. As the growth progresses further, the ink droplets naturally fall onto the ink transfer roller 8 (not shown).

The present invention aims to avoid the natural fall of the ink drip portion 9 by implementing the method according to the present invention before the state shown in FIG. 4 is reached.

FIG. 2 is a sequence diagram for explaining an example in which the method of the present invention is applied to the apparatus shown in FIG.

In FIG. 2, the upper chart on the vertical axis shows the surface speed of the ink fountain roller 1, the lower chart shows the relationship between the ink fountain roller 1 and the ink transfer roller 8, and the horizontal axis shows the relationship between the ink fountain roller 1 and the ink transfer roller 8. Show time.

When the ink dripping part 9 occurs and grows and becomes a large ink dripping part 9' and requires removal treatment, first separate the ink transfer roller 8 in the drum and the ink fountain roller 1 at point A. torso. After the cylinder separation is completed, at time B after some time has elapsed (however, it may be immediately after the cylinder separation is completed), the ink fountain roller 1 is
stop the rotation. The ink fountain roller 1 rotates due to inertia, but eventually stops. In this case, if the inertia is strong, the brake may be activated. When the rotation of the ink fountain roller 1 stops, the ink drip portion 9' moves to the surface of the ink fountain roller 1 and becomes an ink transfer portion 10 (see FIG. 5) and adheres thereto.

After a certain period of time has elapsed, the rotation of the ink fountain roller 1 is started at time C.

At point D, when the transition portion 10 attached to the ink fountain roller 1 passes over the ink transfer roller 8 at least once while the ink transfer roller 8 is separated, the ink transfer roller 8 and the ink fountain are removed. Place roller 1 on the body.

Note that it is preferable that the ink fountain roller 1 is placed on the ink transfer roller 8 after its rotational speed reaches a steady value.

While the ink fountain roller 1 is stopped, the ink transfer roller 8 may be rotating or stopped, but printing cannot be performed because the ink supply is cut off.

Therefore, it is necessary to temporarily suspend the printing operation while the above sequence is executed, but D
Printing is possible after this point.

Here, the transition process of the ink drip portion 9' will be explained in more detail based on FIGS. 4 and 5.

When the ink fountain roller 1 is stopped in the state shown in FIG. 4, the ink dripping portion 9' and the ink thin film 7 are connected by the ink, so that they become one body due to the surface tension of the ink. Note that a certain stopping time is required in order for the integrated ink transition portion 10 to have a stable thickness on the surface of the ink fountain roller 1. Although this time is not constant depending on physical properties such as the viscosity and surface tension of the ink, it is preferably 5 seconds or more.

Next, when the ink fountain roller 1 is rotated, an ink transfer portion 10 is formed.

When the ink transfer portion 10 is passed over the ink transfer roller 8 by the rotation of the ink fountain roller 1, the ink transfer portion 10 is collected into the ink reservoir 4.

Therefore, the ink dripping portion 9 that had formed under the doctor blade 2 is removed, so that after the ink transfer portion 10 passes over the ink transfer roller 8,
Once the ink fountain roller 1 and the ink transfer roller 8 are mounted, printing can be resumed.

As mentioned above, once the ink dripping area 9 occurs, it gradually grows as the printing press runs, and may occur many times. Therefore, when performing continuous printing for a long time, repeat the above sequence several times. also needs to be repeated.

The growth rate of the ink dripping portion 9 is the ink fountain roller 1.
It depends on factors such as the material and hardness of the blade, the shape of the tip of the blade, the size of the gap, the physical properties of the ink, and the rotational speed of the ink fountain roller 1, and it is difficult to understand it uniquely. Once the operating conditions are determined, the situation in which the ink dripping 9 occurs can be fully grasped, and the sequence described above can be designed to meet the conditions.

As described above, the ink dripping portion 9 occurs naturally and often appears periodically at regular intervals, but it may also occur suddenly. Therefore, it is sufficient to carry out the method according to the present invention before the ink dripping portion 9 occurs and the printing device and printed matter are likely to be affected.

As means for detecting the occurrence of the ink dripping portion 9, for example, there is a monitoring device (not shown) such as a phototube or a television camera.
The present invention may be implemented by monitoring the movement and when it becomes necessary to treat the ink dripping portion 9.
Also, as a method for stopping the ink fountain roller 1 for a certain period of time, it is good to install a stop timer (not shown) linked to the above-mentioned monitoring device, or to stop the ink fountain roller 1 every certain rotation. A counter (not shown) may be provided.

FIG. 6 is a sectional view showing an ink supply device and a method of treating the ink dripping portion 9 in a different manner from that shown in FIG.

The apparatus shown in FIG. 6 differs from the apparatus shown in FIG. 2 in that an ink leveling roller 11 is added. Here, the ink transfer area 10 (see FIG. 5) formed by the transfer of the ink dripping area 9 onto the ink thin film 7 on the surface of the ink fountain roller 1 is pressed down by the ink leveling roller 11 and is slightly smaller. Ink transfer section 1
0' and 10'', and an ink sink 12 (stain-like ink) occurs.

Therefore, if the sequence shown in FIG. 2 is executed in this state, the ink shrinkage 12 that occurs when the ink fountain roller 1 is rotated again after it has stopped will be caused by the ink transfer roller 8 (particularly the ink transfer roller 8). If 8 is a plate cylinder, it not only contacts the plate cylinder (which causes printing defects), but also cannot sufficiently remove the transition portion 10'' on the ink leveling roller 11.
Regarding 2, if the rotational (rolling) speed of the ink fountain roller 1 and the ink leveling roller 11 is low, it becomes difficult to occur.

Therefore, the ink fountain roller 1 and the ink leveling roller 11 are rotated in advance at a low speed for a certain period of time to prevent the occurrence of ink smearing 12, and to average these ink transfer portions 10' and 10''. After the thin ink film 7 on the surface is smoothed, the rollers 1 and 11 are rotated normally, the ink fountain roller 1 is placed on the ink transfer roller 8, and printing is resumed.

FIG. 7 is an explanatory diagram showing the sequence between the ink fountain roller 1 and the ink transfer roller 8 when the method according to the present invention is applied to the apparatus shown in FIG.

In this figure, the time from time C' to time C'' is the time during which the ink fountain roller 1 is rotated in advance.

If it is mechanically difficult to rotate the ink fountain roller 1 at a low speed as described above, the same effect can be obtained by inching the roller several times.

[Example] The ink supply device shown in FIG. 1 was used.

The diameter of the ink fountain roller 1 is 60 mm, and the material is NBR.
Made of coated rubber roller, the rubber hardness is 30°. The doctor blade is made of metal, and the vertical thickness of the tip is 0.15 mm, and the rotation speed of the ink fountain roller is 3.2 rps (surface speed approximately 600 mm/sec).

The ink is a non-Newtonian fluid exhibiting thikitropy, consisting of linseed oil, rosin-modified phenolic resin, solvent, pigment, etc.

Under these conditions, the sequence shown in Figure 2 is adopted every 5000 rotations of the ink fountain roller (every 2500 sheets printed), and the time between A and B is 1 second, and the time between B and B is set as the condition.
The present invention was carried out by setting the time between -C to 15 seconds and the time between CD to 2 seconds. As a result, the ink dripping area 9
Most of the ink was transferred into the ink reservoir 4, allowing continuous printing for a long time without any problems.

[Effects of the Invention] By having the above-described configuration, the present invention achieves the following excellent functions and effects.

First, by implementing the present invention, the ink dripping area can be treated extremely easily and in a short time, so the productivity of printed matter is high, and the yield is improved with less staining of the printed matter. do.

Next, since the conventional cleaning work every time an ink drip occurs can be omitted, it is possible to operate for an extremely long time, and the reliability of the apparatus is improved.

Furthermore, since there is no need to manually handle printing ink, a substance that is highly sticky and easily smeared, it is possible to maintain a clean work environment despite the smudged working environment of printing.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an apparatus to which the present invention is applied, FIG.
The figure is an explanatory diagram showing the process of generation and growth of ink dripping parts over time. FIG. 6 is a sectional view showing an ink supply device in a different form from that shown in FIG. 2, and FIG. 7 is an explanatory diagram showing a sequence when the method of the present invention is applied to the device shown in FIG. 1... Ink fountain roller, 2... Doctor blade, 4... Ink reservoir, 5... Ink, 7... Ink thin film, 8... Ink transfer roller, 9... Ink dripping portion, 10... Ink transfer Part, 11... Ink conditioning roller, 12... Ink shrinkage.

Claims (1)

[Claims] 1. A doctor blade is pressed against a rotating ink fountain roller, and the ink in the ink reservoir on the doctor blade is supplied to the circumferential surface of the ink fountain roller to form a desired thickness on the ink fountain roller. In an ink supply method for a printing press, the ink is supplied to the ink transfer roller by forming a thin ink film on the ink fountain roller and bringing the ink thin film into contact with the ink transfer roller, which is attached to the ink fountain roller. After separating the ink fountain roller and the ink transfer roller and stopping the supply of ink from the ink fountain roller to the ink transfer roller, B. Stopping the rotation of the ink fountain roller for a certain period of time, and then removing the ink fountain roller. The ink dripping on the lower surface of the nearby doctor blade is transferred to the ink fountain roller, and after the above-mentioned certain period of time has elapsed, the ink fountain roller is rotated, and the dripped ink transfer portion is transferred to the ink transfer roller that is being moved away. After the ink fountain roller and the ink transfer roller are passed through the ink fountain roller at least once, D. Ink supply method.