JPH01285347A - Keyless ink feeding and adjusting device and method therefor - Google Patents

Abstract

PURPOSE:To eliminate a dispersion in ink density between printing paper surfaces and to eliminate unevenness in ink density between respective colors, by changing the ratio of the rotating peripheral speed of an ink supply roller to that of a mesh roller on the side of the ink supply roller. CONSTITUTION:As a means for changing and adjusting the ratio of the peripheral speed of an ink supply roller 3 to that of a mesh roller 1 on the side of the ink supply roller 3, a variable speed motor 14 actuating in conjunction with the shaft of the ink supply roller 3 through a toothed belt 13 and a control part 15 controlling the variable speed motor are provided. The control part 15 is operated by the input of a signal which is issued, for example, from a rotating number counter 16 for the shaft of the mesh roller 1 by an automatic means by every predetermined count value. Alternatively, the input to the control part 15 can be also performed by using a signal issued according to the comparison of a detection value detected by a means for detecting an ink density on the surface of printing paper 11 with a preset value.

Description

DETAILED DESCRIPTION OF THE INVENTION a) Industrial Field of Application This invention originally relates to an ink supply device for a printing press that has a keyless ink supply function, that is, a function that does not require adjustment of the ink supply amount, and which has a mesh roller as a main part. This invention relates to an apparatus and method for increasing or decreasing the amount of ink that is allowed to pass through the combination of a mesh roller and a doctor blade in contact with the mesh roller, from the standpoint of optimizing the ink density on the printing paper surface.

b) A conventional mesh roller, that is, a roller having fine and regular ink metering cells (indentations) arranged in a row on its circumferential surface;
The combination with the doctor blade for scraping off excess ink, which comes into contact with the circumferential surface of the roller from the direction opposite to the rotational direction, has a remarkable effect of achieving keyless, constant and uniform supply of ink without the need for adjustment. This greatly contributed to making the ink supply system ultra-small, light, simple, and inexpensive.

C) Problems to be Solved by the Invention However, the keyless performance resulting from the above combination has not been able to overcome changes due to usage time from the start of use of the mesh roller to the replacement of old and new mesh rollers. In other words, as shown in Fig. 3, the cell depth C of the mesh roller, which had obtained the ink density B on the paper at the time the mesh roller started to be used, is constantly pressed against its peripheral surface while the mesh roller is in use. As the depth of the cell becomes shallower, the amount of ink that enters the cell decreases, and as the amount of ink supplied decreases, the ink density on the printed paper becomes thinner, and eventually reaches its lowest level. When the appropriate density A is reached, the mesh roller must be replaced with a new mesh roller at the intersection F with the cell depth.

Therefore, the first object of this invention is to suppress within a narrow range the phenomenon of gradual decrease in the density of the printed paper surface that occurs with the operation of the mesh roller, that is, increase in the cumulative number of rotations, to restore the density of the printed paper surface and to maintain a high quality printed paper surface for a long period of time. We would like to be able to obtain the same results over a long period of time, and we would also like to extend the life of the mesh roller itself.

The second object of this invention is to solve the problem of dispersion in ink density between printing paper surfaces caused by differences in the cell depth of each mesh roller in multiple mesh rollers used for simultaneous multi-page printing. I want to adjust the print density to be approximately equal.

A third object of the present invention is to eliminate unevenness in the ink density of each color on the printing paper surface and adjust the desired color tone (color balance) in a plurality of mesh rollers used for supplying multicolor ink.

d) Means for Solving the Problems In order to solve the above three problems, the present invention provides a mesh roller, a doctor blade for ink scraping that comes into contact with the roller, and a peripheral surface of the mesh roller. In a keyless ink supply device that includes an ink supply roller that supplies ink to the mesh roller through circumferential surfaces facing each other through a gap, the rotational peripheral speed of the ink supply roller relative to the rotational peripheral speed of the mesh roller. A drive unit that can change the ratio of the ink supply roller on the side of the ink supply roller, and a control unit that can operate the drive unit are provided.

Furthermore, in order to solve the first problem, the present invention has the following features:
A counter is provided to count the number of rotations of the mesh roller or the number of rotations of other rotating bodies that can be converted into the number of rotations, and the control unit can be operated by human power of a signal emitted every time the counter reaches a predetermined count value. Configure.

The control section may be configured to be operated by inputting a signal obtained by comparing the 1 degree value detected by the ink density detection means on the printing paper surface with a predetermined set density value.

e) Operation When the control section is operated manually or by automatic means, the drive section is activated, and the ratio of the rotational circumferential speed of the ink supply roller to the rotational circumferential speed of the mesh roller is changed on the side of the ink supply roller. be adjusted.

By changing the peripheral speed of the ink supply roller, the amount of ink supplied to the gap between the circumferential surface of the ink supply roller and the circumferential surface of the mesh roller increases or decreases.

By changing the amount of ink supplied to the gap, the velocity distribution within the ink film when passing through one gap changes, and as a result, the ink transfers to the entire circumferential surface of the mesh roller, including the banks within the cells and between the cells. The amount increases or decreases in response to changes in the velocity distribution.

The ink transferred onto the circumferential surface of the mesh roller reaches the position of the doctor blade due to the rotation of the roller, and
This blade scrapes off the excess ink, but in reality, the amount of ink on the mesh roller periphery is reduced due to the slight vibration of the doctor blade's cutting edge and the fact that the ink has a certain degree of viscosity. As the amount of ink increases, the amount of ink that passes through without being scraped off by the cutting edge of the doctor blade also increases.

Since the ink that has escaped scraping by the doctor blade is supplied toward the printing plate surface of the printing cylinder, increasing or decreasing the amount of ink makes it possible to adjust the density of the ink on the printing paper surface.

f) Embodiments A specific embodiment of the present invention will be described in detail below with reference to one drawing.

Figures 1 and 2 show, for example, a mesh roller 1 that rotates to the left, and a doctor blade 2 for scraping off excess ink that comes into contact with the circumferential surface of the roller from a direction opposite to the direction of rotation. Each of the figures shows a keyless ink supply device having a combination of the following, and a mesh roller 1 has fine and regular cells (concavities) arranged in a row on the circumferential surface thereof.

Usually, the ink supply roller 3, which is called a fountain roller, is disposed opposite to the circumferential surface of the mesh roller I on the upstream side in the rotational direction from the position where the doctor blade 2 comes into contact with a gap 4 therebetween, and its lower circumferential surface is The ink is immersed in the ink 6 in the ink fountain 5 and, for example, rotated clockwise, so that the ink adheres to the circumferential surface of the ink and is taken out.

The rotational speed of the ink supply roller 3 is such that the ink adheres to its circumferential surface and rotates at a sufficient circumferential speed to follow the ink, and the ink attached to its circumferential surface is removed from the gap 4 between the ink supply roller 3 and the circumferential surface of the mesh roller 1.
Continue to supply sequentially. On the other hand, the mesh roller I is rotated at a high circumferential speed equivalent to the circumferential speed of the first plate cylinder 9 because ink is supplied to the first plate cylinder 9 in a continuous state with no gaps. Conventionally, the peripheral speed ratio of the ink supply roller 3 and the mesh roller 1 is normally set to a constant value during subsequent operation, except for the initial adjustment.

A pair of ink deposit rollers 7 and 8 are provided in contact with two points on the circumferential surface of the mesh roller 1 on the downstream side in the rotational direction from the position where the doctor blade 2 contacts, and furthermore, the ink deposits are The plate cylinder 9 is connected to the other circumferential surface of the plate cylinder, and the blanket cylinder 10 is connected to the other circumferential surface of the plate cylinder, and the printing paper 11 is connected to the other circumferential surface of the blanket cylinder. It runs, and one side of it is printed. 12 is a water supply mechanism to the plate cylinder 9.

Now, as shown in Figure 3 and already mentioned,
The paper surface ink density of the printing paper 11 is caused by the fact that as the cumulative number of revolutions of the mesh roller 1 increases, the depth of the cells becomes shallower due to wear by the doctor blade 2, and the amount of ink conveyed becomes insufficient. As a result, it becomes gradually thinner, and in the past, it has not been possible to change or adjust this phenomenon of gradual decrease in printed paper surface density.

On the other hand, the inventors of the present application have proposed that the ink supply roller 3
It was discovered that by increasing the circumferential speed of the mesh roller 1 relative to that of the mesh roller 1, the ink density on the printed paper surface increases, and by decreasing it, the ink density on the printed paper surface becomes thinner (the details will be described later). .

The present invention is based on the discovery of this fact and applies it to a keyless ink supply device. In other words, the ink supply roller 3 relative to the circumferential speed of the mesh roller]
In the embodiment shown in FIG. 1, a variable speed motor 14 interlocked with the shaft of the ink supply roller 3 by a toothed belt 13 is used as a means for changing and adjusting the ratio of the circumferential speed of the ink supply roller 3 on the side of the ink supply roller 3. Control unit 1 that controls the variable speed motor
5, and the control unit 15 automatically controls, for example, a revolution counter 16 of the shaft of the mesh roller 1.
It is operated by inputting a signal emitted every predetermined count value from . However, if it is considered that the degree of wear of the cell depth of the mesh roller l can be detected indirectly, the number of rotations of a rotating body other than the mesh roller may be counted. Manually, it is also possible to use a signal generated by comparing a detection value detected by a paper surface ink density detection means (not shown) of the printing paper 11 with a predetermined setting value.

FIG. 4 shows that a signal is generated every predetermined number of rotations of the mesh roller 1 and the control unit 15 is operated, thereby
The phenomenon in which the ink density on the printing paper surface recovers each time when the circumferential speed of the ink supply roller 3 is increased is diagrammatically shown in comparison with FIG. The circumferential speed of the ink supply roller 3 is increased from the time H6 to H@ reached, and is controlled so that it reaches the maximum value of the variable allowable range, for example, at the final time H1. As a result, the life of the mesh roller 1 is extended from point F to point G.

The embodiment shown in FIG. 2 is equipped with a continuously variable transmission 17, whose input shaft 18 is interlocked with the rotating shaft of the mesh roller l by a toothed belt 21, and a motor that drives the gear ratio converter. 22 and.

This figure shows a configuration including a control section 23 for operating the motor 22, and similarly to the embodiment shown in FIG. When the mesh roller 1 is operated, the transmission ratio of the power from the mesh roller 1 is changed and the power is transmitted to the ink supply roller 3.

In both cases of Fig. 1 and Fig. 2, the operator visually checks the ink density on the printed paper surface and
5 or 23 may be given a manual input signal 24 to operate it.

FIG. 5 shows that, based on the test results of the inventors of the present application, the printing paper surface is This is a graph showing the relationship in which the ink concentration changes, and the ink used has a viscosity of 25% as measured by type B viscosity.
．． 0±2 points (measured at 25°C), the color is black, the narrowest gap between both rollers is 0.3 am, however, the printing speed is approximately 545 m/min for X and approximately 454 m/min for Y. Ta.

As is clear from the graph in FIG.
As the recording speed decreases, the ink density on the printed paper surface decreases.

The details of the occurrence of such a correlation between the two will be explained with reference to FIGS. 6 and 7, comparing two cases where the circumferential speed ratio of the two is 1:50 and 1:25, for example.

A and B in FIGS. 6 and 7 show the relationship between the state of the ink passing through the gap 4 and the compressive force acting on the ink. The ink is smaller than the film thickness (for example, set to about 0.3 mm, and the ink is pushed through the gap 4 and passes through it,
It becomes stable when the pushing and spreading force is balanced with the reaction forces from the ink supply roller 3 and the mesh roller 1. In other words, the amount of ink that passes through the gap 4 is determined by the amount of ink supplied by the ink supply roller 3 and the circumferential speed of the ink supply roller 3, and a reaction force of approximately 2 is generated depending on the amount.
A compressive force acts on the ink passing through the gap 4.

Figure 6 shows the ink supply roller 3 and mesh roller l.
The case where the circumferential speed ratio is, for example, 1:50 is shown.

In this case, the ink supplied from the circumferential surface of the ink supply roller 3 is gradually subjected to compressive force from a portion at a distance slightly smaller than the ink film thickness on the inlet side of the gap 4, and the maximum compressive force is exerted at a portion slightly closer to the inlet than the narrowest portion. After that, the pressure is reduced to -qi (Fig. 6, B6).

Then, bubbles are generated within the ink film due to the rapid pressure reduction action. Furthermore, since the circumferential speeds of the two rollers are different, the flow velocity distribution in the thickness direction of the ink film passing through the gap 4 is such that the fastest circumferential portion is biased toward the circumferential surface of the mesh roller 1, which has a faster circumferential speed ( At this time, the separation of the ink film after passing through the gap 4 occurs along the bubbles at the fastest circumferential portion, and the cell portion is slightly depressed due to surface tension. become. The rotation of the mesh roller l, which has received the ink, causes the doctor blade edge 2 to
1, and the ink is leveled by this cutting edge 21.

However, since the ink has a relatively high viscosity, the cell part 1
Excess ink on the embankment 12 surrounding the doctor blade 1 does not flow into the ink recess of the cell 11, and most of it flows into the cutting edge 2 of the doctor blade.
2, it separates from the circumferential surface of the mesh roller 1, falls into the ink fountain 5, and is collected.
1 (between the solid line position and the two-dot chain line position in Figure 6), it escapes scraping, passes through the blade edge 21, and remains on the bank 12 of the mesh roller l (see Figure 5, left side e). , and if the circumferential speed of the mesh roller l and the contact pressure of the doctor blade cutting edge 21 are constant, it is estimated that the slight vibration of the cutting edge 21 is stably generated in a substantially constant state.
The ink on the circumferential surface of the mesh roller l that has passed through the contact position of the doctor blade cutting edge 21 becomes substantially constant and uniform, as shown in FIG. 6C.

Figure 7 shows the ink supply roller 3 and mesh roller 1.
The circumferential speed difference between the
The case where it is set to 5 is shown.

In this case, the amount of ink passing through the gap 4 increases because the circumferential speed of the ink supply roller 3 increases relative to the circumferential speed of the mesh roller 1, and the force that expands the gap and the reaction force generated accordingly also increase. In addition, since the compressive force acting on the ink increases and becomes larger than the case shown in FIG. When the difference is larger), there is a shift toward the outlet side (see Figure 7B), which causes air bubbles in the ink film.Also, the flow velocity distribution in the thickness direction of the ink film passing through the gap 4 is the fastest, as described above. Although the peripheral part is biased toward the peripheral surface of the mesh roller 1, the ink film is shifted closer to the center of the ink film by the amount that the peripheral surface of the ink supply roller 3 approaches the peripheral surface of the mesh roller l (see FIG. 7A). Therefore, at this time, the separation of the ink film after passing through the gap 4 is thought to occur along the bubbles at the fastest peripheral part of the ink film, as described above, but the separation is transferred to the circumferential surface of the mesh roller 1. The ink is cell part 11 of mesh roller l.
The area is filled to the brim, and the area becomes even more mounded to some extent. Also regarding the circumferential surface of the mesh roller 1 that received the ink in FIG. 7AB.

Mesh roller 1 that received ink in FIG. 6AB above
The same effect as that on the circumferential surface of the mesh roller l occurs on the doctor blade 2, and slight vibrations of the doctor blade cutting edge 21 (between the solid line position and the two-dot chain line position in FIG. 7) also occur, and the circumferential surface of the mesh roller l receives It is estimated that the amount of ink that passes under the doctor blade cutting edge 21 increases as the excess ink increases.
As shown in FIG. 7C, the ink on the circumferential surface of the mesh roller l that has passed through the contact position 1 is more raised than in FIG. 6C (see e on the right side of FIG. 5). It becomes constant and uniform.

In either case shown in FIGS. 6 and 7, the peripheral surface of the mesh roller 1 that has passed the contact position of the cutting edge 21 of the doctor blade is free from ink adhesion to the roller 7 as the mesh roller 1 continues to rotate. .8 and transfer the ink to them, and then return to the part facing the circumferential surface of the ink supply roller 3 with a gap 4 in between.

The ink adhering roller 7.8 is a mesh roller l.
The ink received from the printer is supplied to the printing plate on the printing cylinder 9 and transferred to the printing paper 11.

g) Effects of the Invention As detailed above, the present invention provides a keyless ink supply device that has hitherto not required ink supply adjustment. MEC 10-
The ratio of the rotational peripheral speed of the ink supply roller 3 to the rotational peripheral speed of the roller 1 can be changed and corrected by increasing or decreasing the ratio of the rotational peripheral speed of the ink supply roller 3 to the rotational peripheral speed of the ink supply roller 3 by manual or automatic means.

As a result, by increasing the rotational speed of the ink supply roller 3 in accordance with the increase in the cumulative rotational speed of the mesh roller 1, it is possible to suppress a decrease in the ink density value on the paper surface to be printed, and also to Accordingly, the service life of the mesh roller itself can be extended.

Furthermore, when printing multiple pages at the same time using multiple printing machines, such as newspaper rotary presses, the present invention is capable of printing even if there are variations in printed paper surface density caused by differences in mesh roller wear in each printing machine. By adjusting the rotation of each ink supply roller by increasing or decreasing the rotation of each ink supply roller, it is possible to change and adjust the printing density of all pages almost equally without replacing the printing roller.

Furthermore, in the case of multicolor printing presses, in the past, spare mesh rollers were prepared and the depth of the mesh roller cells was slightly changed for each color of ink to adjust the color tone (color balance). In the present invention, this is not necessary, and it is possible to eliminate unevenness in the ink density of each color by adjusting the circumferential speed of each ink supply roller, thereby obtaining a desired color tone (color balance).

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an embodiment of the device of the present invention. FIG. 2 is an explanatory diagram showing an embodiment different from that in FIG. 1. FIG. 3 is a graph showing the interrelationship changes between the cell depth of the mesh roller, the ink density on the paper surface, and the cumulative rotational speed of the roller. A graph showing how the ink density on the printing paper surface is prevented from decreasing by means of gradually increasing the amount of ink passing through the mesh roller. FIG. 6 is a graph showing the change in the interrelationship between the ink supply roller and the mesh roller and the density on the printed paper surface. When the circumferential speed ratio of the ink supply roller and mesh roller is 1:50, the state of transfer of ink supplied from the former to the latter and the final passing ink are shown in FIG. It is an explanatory diagram showing the relationship with quantity in an enlarged manner,
Among them, A illustrates the aspect of ink transfer in the opposing gap between the two, B shows the compressive force distribution diagram acting on the ink in A, and C shows the amount of ink that has passed through without being scraped by the doctor blade. FIG. 7 is an explanatory diagram showing an enlarged view of the relationship between the state of transfer of ink supplied from the former to the latter and the final amount of ink passing when the circumferential speed ratio of the ink supply roller and mesh roller is 1:25. Among them, A illustrates the aspect of ink transfer in the opposing gap between the two, B shows the compressive force distribution diagram acting on the ink in A, and C shows the amount of passing ink that has not been scraped by the doctor blade. l...Mesh roller, 11... Its cell part, 12... Its bank part, 2... Doctor blade, 2I... Its cutting edge. 22...Blade area, 3...Ink supply roller (fountain roller)
). 4...Gap, 5...Ink fountain, 6
... Ink, 7 and 8 ... Ink is deposited on roller, 9 ... Plate cylinder, lO ... Blanket cylinder, ll ... Printing paper, 12 ... Water supply mechanism, 13 ...Toothed belt, 14...Variable speed motor. 15...Control unit. 16...Rotation speed counter. 17...Continuously variable transmission, 18...Input shaft, 19...Toothed belt, 20...Output shaft. 21...Toothed belt, 22...Motor. 23...Control unit, 24...Manual input signal.

Claims (4)

[Claims] (1) A mesh roller, a doctor blade for ink scraping that comes into contact with the roller, and an ink supply roller that supplies ink to the mesh roller with its circumferential surface facing the circumferential surface of the mesh roller through a gap. The main part of the keyless ink supply device includes a drive unit that can change the ratio of the peripheral rotational speed of the ink supply roller to the rotational peripheral speed of the mesh roller on the side of the ink supply roller, and a drive unit that can operate the drive unit. A keyless ink supply adjustment device equipped with a control unit and. (2) A counter for counting the number of rotations of a rotating body that can be regarded as a device that can indirectly measure the degree of wear of the depth of cells on the circumferential surface of the mesh roller, and the counter reaches a predetermined count value. The keyless ink supply adjustment device according to claim 1, further comprising: the control section that is operated by inputting a signal issued every time the keyless ink supply adjustment device is pressed. (3) The control unit is configured to be operated by inputting a signal obtained by comparing the density value detected by the ink density detection means on the printing paper surface with a predetermined set density value. The keyless ink supply adjustment device described. (4) In the keyless ink supply adjustment device according to claim 1, the ratio of the rotational peripheral speed of the ink supply roller to the rotational peripheral speed of the mesh roller is increased or decreased on the side of the ink supply roller by manual or automatic means. A keyless ink supply adjustment method characterized by: