JPH0342587B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printing method in an offset sheet-fed printing press, and more specifically, it emits a constant amount of ink without making fine adjustments to the ink fountain screw, and prints regardless of the pattern on the plate. This is the printing method used.

Conventionally, when printing on sheet-fed paper using an offset sheet-fed printing machine, the pattern area of the plate is measured using a printing plate pattern area ratio meter, the opening/closing angle of each screw in the ink fountain is set, and each screw in the ink fountain is automatically adjusted. The amount of ink flowing out was adjusted and released according to the pattern on the plate.

Alternatively, in the case of offset sheet-fed printing machines, on-site technicians used years of intuition and experience to carefully open and close each ink fountain screw by hand, matching it to the pattern on the plate, resulting in a lot of wasted printing and poor finishing quality. It has the drawback that it takes time to stabilize, and the automatic ink adjustment device of the offset sheet-fed printing press has the drawback that the equipment is expensive.

The present invention was developed for the purpose of providing a printing method that eliminates the need for fine adjustment of the ink fountain screw in an offset sheet-fed printing machine, and that allows a uniform print finish to be obtained regardless of the pattern on the plate, with constant constant discharge of ink. .

To explain one embodiment of the method according to the present invention, in an offset sheet-fed printing machine, all the ink fountain screws 1 are opened at a constant rate in advance so that a constant amount of ink is discharged, and the printing area A3 (the printing area A3) is placed on the plate cylinder 2. (See Figure 2) and a normal plate A1 with a non-image area A4, and the area is compressed from less than 1 time to more than 1/10 of that of the plate, and the image area on the film corresponding to the image area of the plate is the image area ratio. An auxiliary plate portion A2 having a relative printed area A5 and a non-printed area A6 measured with a meter and averaged is provided, and ink is applied to the plate via each inking roller 3,
The plate and auxiliary plate portion A are rotated in contact with a blanket cylinder 6 having a blanket 8 of a corresponding size.
The ink of No. 2 is transferred onto the blanket, and the impression cylinder 4 is used to print on a sheet of paper B1 of a corresponding size, and the sheet is transferred so that no excess ink remains on the printing area A3 of the printing plate. The remaining ink is printed on extra paper B2 having an area less than 1 times and more than 1/10 of the area of plate A1 attached to paper B1, and after being consumed, it is discarded, and the area of the image on printing plate A1 is calculated in advance by the image area. There is no need to measure with a rate meter, install an automatic ink bottle screw adjustment device using numerical control, or make detailed manual adjustments of the ink bottle screw based on intuition, and even if a certain amount of ink is ejected, it will be uniform on the print area A3. This is a printing method used in offset sheet-fed printing presses that allows ink to be placed on the sheet-fed offset press.

The present invention consists of the method as described above, and one embodiment of the present invention will be described in detail.As shown in FIG. 3 to the plate A1 provided on the plate cylinder 2, the amount of ink supplied differs depending on the image area A3 or the non-image area A4 on the plate. A3 and non-printing area A4
A printed area A5 and a non-printed area A6 having areas obtained by measuring and averaging the pattern area on the film corresponding to
An auxiliary plate section A2 correspondingly provided is provided in series to uniformly apply a fixed amount of ink.

The regular version A1 has a drawing area A3 and a non-printing area A.
4, and the relative printing area A of the auxiliary printing area A2
The area of 5 can be compressed to less than 1 times and more than 1/10 by measuring the image in the drawing area of the normal plate A1 with a pattern area ratio meter and averaging it, so an extra auxiliary plate area corresponding to this will be compressed. It is good to provide A2.

It is then transferred to a blanket 8 provided on the blanket cylinder 6 and having a corresponding area, and further printed onto a printing paper B1 having an area corresponding to the area of the plate A1 and the auxiliary plate section A2 which are fed to the impression cylinder 4.

As shown in FIG. 2, a printed area A3 and a non-printed area A4 of a normal printing plate A1 can be displayed as being roughly divided by a diagonal line G.

Therefore, if a printing area A5 having an area inversely proportional to this is provided in the auxiliary printing area A2, a certain amount of ink is uniformly consumed as a whole by the printing plate A1 and the auxiliary printing area A2. So it won't be uneven.

However, making completely similar plates of the same size would be wasteful, so measure the area of the pattern corresponding to the plate on the film in advance using a pattern area ratio meter, and create the auxiliary plate section A2 by averaging the values. For example, regular version A1 1
The area of the extra printing paper B2 will be equal to or less than 1/10, and by cutting off the extra printing paper B2, the printing paper B1 will be correctly printed on the plate A1. It is possible to reproduce the pattern.

In general, it is ideal to make auxiliary plates of the same size and completely similar shapes, but in reality there are constraints on the diameter of the plate cylinder, and there are many unnecessary non-printing areas, so the auxiliary plate part A2 It is advantageous to make the plate smaller than the normal plate A1. In this case, depending on the area of the printing area, the printing area A of the normal plate area A1 as shown in FIG.
3, the area of P, P, P, P and non-printing area A4
In the area where the area ratio of P, P, P, P exceeds a certain range (approximately the shaded area), the auxiliary printing section A2 cannot correct it. Therefore, in this area, it may be necessary to manually adjust the opening/closing angle of the ink fountain screw and make corrections to uniformly deposit ink on the printing area A3 of the normal plate area A1.

As described above, in offset sheet-fed printing machines, in order to finely adjust the amount of ink flowing into the ink pot using the pattern on plate A1, there is no need for expensive computer-controlled equipment or engineers with years of experience and intuition. This is an invention of a printing method for an offset sheet-fed printing press that allows anyone with ordinary printing skills to easily engage in printing work.

[Brief explanation of drawings]

The drawings show an embodiment of the method according to the invention, in which FIG. 1 is a schematic diagram of a printing machine, FIG. The figure shows the printing paper, and FIG. 4 shows the plate when the ratio of the area of the printed area to the non-printed area exceeds a certain range. 1...All ink fountain screws, 2...Print cylinder, 3...Inking roller, 4...Impression cylinder, 5...Sheet paper,
6... Blanket body, 7... Urn, 8... Blanket, G... Approximately diagonal lines, A1... Said version, A2
...Auxiliary printing section, A3, A5... Drawing section, A4, A
6... Non-printing area, B1... Sheet, B2... Extra paper.

Claims (1)

[Claims] 1. In an offset sheet-fed printing press, all ink fountain screws 1 are opened at a constant rate in advance so that a constant amount of ink is discharged, and the printing area A3 and the non-printing area A4 are printed on the plate cylinder 2.
Relative drawing area A5 and non-printing area A are compressed to an area of approximately 1 times or less to 1/10 or more of that of the printing plate, and the image area is measured and averaged to a normal printing plate A1.
6 is provided, and ink is applied via each ink application roller 3, and the ink is applied to the plate A1 and the auxiliary plate part A2 by rotating in contact with a blanket cylinder 6 having a correspondingly sized blanket 8. is transferred onto the blanket, and is further printed on a sheet 5 of a corresponding size by the impression cylinder 4, and is transferred onto the sheet B1 so that excess ink does not remain in the image area A3 of the plate. After printing, discard the remaining ink on extra paper B2 having an area of 1 times or less and 1/10 or more of the continuous plate A2, and then cut it off. Measure the area of the pattern on the printing plate A1 in advance with a pattern area ratio meter. , there is no need to install an automatic ink bottle screw adjustment device using numerical control or perform fine manual adjustments of the ink bottle screw based on intuition, and even if a certain amount of ink is ejected, the image area A3
A printing method for offset sheet-fed printing machines that allows ink to be placed evenly on the surface of the sheet.