JPH1191075A - Method for controlling thickness of ink film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the density of printed matter from decreasing on the opposite sides thereof by increasing the opening of an ink fountain key at the opposite sides as compared with the central part, actuating an ink doctor roller and forming an ink thickness distribution becoming thinner toward the downstream side in an ink roller group. SOLUTION: When an ink roller group 6 retains no ink, a fountain roller rotational amount controller sets the rotational amount of an ink fountain roller 3 at 50% and an ink key opening controller sets the opening of ink fountain keys 4-1,..., 4-n wider at the opposite sides as compared with the central part. Subsequently, a call controller controls an ink doctor roller 5 to perform ink transfer operation eleven times. Consequently, a minimum necessary ink thickness distribution becoming thinner toward the downstream side is formed in the ink roller group 6. According to the method, a substantially constant gradient of ink thickness distribution can be ensured over the entire key zone.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling an ink film thickness in an ink supply device for supplying ink in an ink fountain to a printing plate via an ink roller group.

[0002]

2. Description of the Related Art FIG. 4 shows a main part of an ink supply device in a rotary printing press. In the drawing, 1 is an ink fountain, 2 is ink stored in the ink fountain 1, 3 is an ink fountain roller, and 4 (4-1 to 4-n) are provided in parallel with each other in the axial direction of the ink fountain roller 3. Reference numeral 5 denotes an ink fountain key, 5 denotes an ink transfer roller, 6 denotes an ink roller group, and 7 denotes a printing plate.

In this ink supply device, the ink 2 in the ink fountain 1 is supplied to the ink fountain roller 3 by adjusting the opening of the ink fountain keys 4-1 to 4-n, and the ink supplied to the ink fountain roller 3 is transferred to the ink. The ink is supplied to the printing plate 7 through the ink roller group 6 by the operation of calling the roller 5.

When the printing plate 7 is replaced with a new printing plate 7 ', the opening of the ink fountain keys 4-1 to 4-n and the rotation of the ink fountain roller 3 are adjusted to values corresponding to the pattern of the new printing plate 7'. The amount etc. are preset. That is, the ink fountain key 4-
The ink 2 in the ink fountain 1 is transferred to the new printing plate 7 ′ via the ink roller group 6 by setting the degree of opening of the ink fountain roller 3, the rotation amount of the ink fountain roller 3, and the like as values according to the pattern of the new printing plate 7 ′. Supplied to In this case, test printing is performed before final printing to adjust the ink supply amount and obtain a satisfactory color tone. Thus, a desired ink film thickness distribution (gradient of ink film thickness) is created in the ink roller group 6.

In this ink supply apparatus, when the printing plate 7 is replaced with a new printing plate 7 ′, the ink film thickness distribution with respect to the old printing plate 7 remains in the ink roller group 6. That is, in this case, it is necessary to gradually change the ink film thickness distribution for the old printing plate 7 to the ink film thickness distribution for the new printing plate 7 ', and to adjust the ink supply amount until a satisfactory color tone is obtained. Excessive trial printing is required.

Therefore, before exchanging the printing plate 7, it is necessary to turn off the call-out operation of the ink transfer roller 5 and perform printing on a blank sheet to make the ink film thickness distribution on the ink roller group 6 zero. Will be In this case, the ink roller group 6 does not hold ink, and an ink film thickness distribution for the new printing plate 7 'is formed from the beginning on the ink roller group 6. Here, as a method of forming the ink film thickness distribution from the state in which the ink roller group 6 does not hold ink, the ink is directly applied to the ink roller group 6 by an ink spatula based on the experience of an operator, and a pattern area ratio measuring device is used. A method is used in which a call is made and ink is applied while the created key point is being opened. Even when the ink roller group 6 does not hold ink when the printing plate 7 is set, for example, at the beginning of work, the formation of the ink film thickness distribution is performed in the same manner.

[0007]

However, in the conventional method of forming the ink film thickness distribution, the method cannot be quantified because the method depends on the operator's experience. Further, in the method (1), the work can be quantified, but a desired appropriate film thickness (concentration) cannot be obtained, and it takes time to bring the ink film thickness distribution into an equilibrium state.

Therefore, the present applicant has filed Japanese Patent Application No. Hei 8-16771.
No. 44, when forming an ink film thickness distribution according to the pattern of the printing plate 7 (7 ') on the ink roller group 6, when the ink roller group 6 does not hold ink, the ink fountain keys 4-1 to 4-n The opening of the ink fountain roller 3 is set to a predetermined amount of rotation, the opening of the ink fountain roller 3 is set to a predetermined amount of rotation, and the ink transfer roller 3 is called by a predetermined number of times. The minimum ink film thickness distribution Ma (see FIG. 5 (a)) required during printing in which the ink roller group 6 becomes thinner from upstream to downstream, that is, a portion of the printing plate 7 (7 ') without a pattern Is formed, and then the ink fountain key 4 is formed.
The opening degree of -1 to 4-n is preset to a value corresponding to the pattern of the printing plate 7 (7 '), the ink transfer roller 5 is called up a predetermined number of times, and the ink film formed on the ink roller group 6 is operated. A technique has been proposed in which an ink film thickness distribution Mb (see FIGS. 5B and 5C) corresponding to the pattern of the printing plate 7 (7 ′) is superimposed on the thickness distribution Ma.

According to this technique, the time until the ink film thickness distribution is brought into an equilibrium state is shortened, "reduction of preparation time before printing", "reduction of labor load", "saving of printing materials",
"Improvement of production efficiency" and "reduction of cost" can be realized. However, the ink supply device has a swing roller that swings the ink roller group 6 in the lateral direction. Since the swing roller is longer than the other kneading rollers, if the ink fountain keys 4-1 to 4-n are opened at a fixed opening, the ink at both ends flows into the ends,
The ink in the ink supply device does not flatten right and left (the ink film thickness at both ends is small). That is, when an attempt is made to form the minimum ink film thickness distribution Ma required during printing on the ink roller group 6, the ink fountain key 4-
Among the key zones formed by 1 to 4-n, the gradient of the ink film thickness distribution Ma of the key zone on both side portions is smaller than the gradient of the ink film thickness distribution Ma of the key zone on the central portion. On both sides of the printed matter, the actual density value is lower than the target density value (see the shaded portion shown in FIG. 6).
It will be pale.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to prevent a density reduction on both sides of a printed matter and to make an actual density value close to a target density value. An object of the present invention is to provide a control method of a possible ink film thickness.

[0011]

In order to achieve the above object, the present invention provides a method of forming an ink film thickness distribution according to the pattern of a printing plate on an ink roller group. If not, set the opening of the ink fountain key so that the opening of the ink fountain key on both sides is larger than the opening of the ink fountain key in the center part, and set the rotation amount of the ink fountain roller to a predetermined amount, By operating this machine and invoking the ink transfer roller a predetermined number of times, the minimum ink film thickness distribution required during printing that becomes thinner from upstream to downstream in the ink roller group is formed. Things. According to the present invention, an ink roller group that does not hold ink
By setting the opening of the ink fountain key on both sides to be larger than the opening of the ink fountain key in the central portion, an ink film thickness distribution Ma corresponding to a portion of the printing plate having no picture is formed.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments. FIG. 2 is a block diagram showing a hardware configuration of an ink supply device to which the present invention is applied. In the figure, 8 is a CPU, 9 is a ROM, 10 is a RAM, 1
Reference numerals 1 and 12 denote interfaces, 13 denotes a touch panel display, 14 denotes a printing machine control device, 15 denotes a calling mechanism ON / OFF control device (hereinafter referred to as a calling control device), 16 denotes a fountain roller rotation amount control device, and 17 denotes an ink key. The opening control device 18 is a floppy disk drive (hereinafter referred to as a drive device).

The CPU 8 includes interfaces 11 and 12
And performs various processing operations according to a program stored in the ROM 9 while accessing the RAM 10. Various processing information in the CPU 8 is output to the display 13, the printing machine control device 14, the call control device 15, the fountain roller rotation amount control device 16, the ink key opening degree control device 17, and the drive device 18 via the interfaces 11 and 12. You.

In FIG. 4, a printing plate 7 is
In making the ink film thickness distribution according to the pattern of (7 ′), when the ink roller group 6 does not hold ink,
“Preinking” is selected on the ink film thickness control screen on the display 13. That is, the display 1
On the ink film thickness control screen 3 above, touch the display surface of "pre-inking".

Then, the CPU 8 controls the printing machine control device 1.
4 to rotate the machine at a low speed (step 101 shown in FIG. 1). And the acupoint roller rotation amount control device 1
6 and the rotation amount of the ink fountain roller 3 is reduced by 50%.
(Step 102). Also, a command is sent to the ink key opening degree control device 17 and the ink fountain keys 4-1 to 4-n are sent.
Is set so that the opening of the ink fountain key on both sides is larger than the opening of the ink fountain key on the center (step 103). For example, if the ink fountain key 4 is 2
If one is used, as shown in FIG.
O. 1 "and" NO.21 "have an opening of 60%, and" NO.
The opening degree of “NO. 2” and “NO. 20” is 55%, and “NO.
O. 19 "is 50%.

Then, a command is sent to the printing machine controller 14 to turn on the high-speed operation (step 104), and the printer is operated at a high speed (step 105). When the machine reaches a predetermined operation speed (7000 rpm), the CPU 8 sends a command to the call control device 15 to turn on the call (step 106), and causes the ink transfer roller 5 to perform a call operation 11 times (step 106). 107), the call is turned off (step 108). As a result, the minimum ink film thickness distribution Ma required during printing is formed in the ink roller group 6 as shown in FIG.

In this case, the ink fountain keys 4-1 to 4-n
Because the opening of the ink fountain key on both sides is larger than the opening of the ink fountain key in the center,
Among the key zones formed by the ink fountain keys 4-1 to 4-n, the gradient of the ink film thickness distribution Ma in the key zones on both sides is the ink film thickness distribution M in the key zone in the central portion.
It is avoided that the gradient is smaller than the gradient of a, and almost the same gradient can be obtained for all the key zones.

Thereafter, the CPU 8 sends commands to the ink key opening degree control device 17 and the fountain roller rotation amount control device 16 to determine the opening degrees of the ink fountain keys 4-1 to 4-n and the rotation amount of the ink fountain roller 3 on the plate 7. The value is preset to a value corresponding to the pattern of (7 ') (step 109). That is,
The CPU 8 reads out the picture area ratio of each zone of the printing plate 7 (7 ') corresponding to the ink fountain keys 4-1 to 4-n from the floppy disk set in the drive device 18, and according to this picture area rate. Ink fountain key 4-1
The opening degree of 4-n and the rotation amount of the ink fountain roller 3 are obtained, and these are preset as data for final printing.

In this embodiment, the printing plate 7
In the measurement of the pattern area ratio for each zone of (7 '), Japanese Patent Application Laid-Open Nos. 58-201008 and 58
No. 2010010, a "pattern area ratio measuring device" is used, and the pattern area ratio measured using the "pattern area ratio measuring device" is written on a floppy disk. The written floppy disk is set in the drive device 18. In addition,
The CPU 8 is connected to the "picture area ratio measuring device" online, and the printing plate 7 (7 ') is directly connected to the "picture area ratio measuring device".
May be taken in for each zone.

Next, the CPU 8 sends a command to the call control device 15 to turn the call ON (step 110), and after the ink transfer roller 5 performs the call operation six times (step 111), turns the call OFF (step 112). And As a result, as shown in FIGS. 5B and 5C, the printing plate 7 (7 ′) has a minimum ink film thickness distribution Ma required during printing formed on the ink roller group 6. Is superimposed on the ink film thickness distribution Mb corresponding to the pattern of (a).

FIG. 5 (b) shows the ink film thickness distribution in the key zone having a large number of patterns. The ink film thickness distribution Mb having a large gradient is superimposed on the minimum ink film thickness distribution Ma required during printing. You. FIG. 5 (c) shows the ink film thickness distribution in the key zone where the pattern is small, and the ink film thickness distribution Mb with a small gradient is changed to the minimum ink film thickness distribution Ma required during printing.
Are superimposed.

The CPU 8 controls the printing machine control device 1.
4 to start the trial printing (step 113).
After ten test prints have been performed (step 114), the machine is stopped (step 115). The operator checks the density of the test-printed material (step 116). Here, if the color tone is satisfactory, the control of the ink film thickness by pre-inking is terminated (step 11).
7) Start printing.

In this case, since the gradient of the ink film thickness distribution Ma is substantially equal in all the key zones, the density reduction on both sides of the printed matter is prevented, and the actual density value becomes the target density value. Get closer. Step 1
If the opening of the ink fountain keys 4-1 to 4-n preset in step 09 is corrected and set so that the opening of the ink fountain keys on both sides is larger than the opening of the ink fountain keys in the center, the both sides of the printed matter can be obtained. It is possible to further prevent the concentration from decreasing on the side.

If the test print does not have a satisfactory color tone, the operator selects pre-inking (+) or pre-inking (-) on the ink film thickness control screen on the display 13 (step 118). This makes it possible to make fine adjustments to the ink supply amount to bring the color tone closer to a satisfactory color tone.

In this pre-inking, the rotation of the ink fountain roller 3 is set to 50% in step 102, and the ink fountain keys 4-1 to 4-4 are set in step 103.
Although the opening degree of -n is set to 60%, 55%, and 50%, it is not limited to this value. Further, the number of calls in steps 107 and 111 and the number of test prints in step 114 are not limited to these values. These values can be changed according to the situation.

[0026]

As is apparent from the above description, according to the present invention, the ink fountain keys on both sides of the ink roller group having no ink are made to have a larger opening than the ink fountain keys at the center. As a result, the minimum ink film thickness distribution Ma required during printing is formed, and the ink film thickness distribution M is obtained for all key zones.
The gradient of “a” is made substantially equal, and a decrease in the density on both sides of the printed matter is prevented, so that the actual density value approaches the target density value.

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating an ink film thickness control operation by breaking.

FIG. 2 is a block diagram illustrating a hardware configuration of an ink supply device to which the present invention is applied.

FIG. 3 is a diagram showing an example of setting an opening of an ink fountain key in step 103 shown in FIG. 1;

FIG. 4 is a diagram illustrating a main part of an ink supply device in a rotary printing press.

FIG. 5 is a diagram showing ink film thickness distributions Ma and Mb formed on an ink roller group.

FIG. 6 is a diagram illustrating a situation where an actual density value is lower than a target density value on both sides of a printed material.

[Explanation of symbols]

1: Ink fountain, 2: ink, 3: ink fountain roller,
4 (4-1 to 4-n): ink fountain key, 5: ink transfer roller, 6: ink roller group, 7, 7 '... printing plate, 8 ...
CPU, 9 ROM, 10 RAM, 11, 12 interface, 13 display (touch panel type), 14 printing machine control device, 15 call control device,
16: Pot roller rotation amount control device, 17: Ink key opening control device, 18: Drive device.

Claims (1)

[Claims] An ink fountain key is provided in parallel in the axial direction of an ink fountain roller, and ink in the ink fountain is supplied to the ink fountain roller by adjusting the opening of the ink fountain key. An ink supply device for supplying ink to a printing plate via an ink roller group by a call operation of an ink transfer roller, wherein the ink roller group is used for forming an ink film thickness distribution according to a pattern of the printing plate on the ink roller group. When the ink fountain key is not possessed, the opening of the ink fountain key is set to be larger than the opening of the ink fountain key in the central part, and the rotation of the ink fountain roller is adjusted. Quantitative,
The machine is operated and the ink transfer roller is operated a predetermined number of times to form a minimum ink film thickness distribution required during printing in which the ink roller group becomes thinner from upstream to downstream. A method for controlling an ink film thickness, characterized in that: