JPH0216226B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a printing method capable of printing with arbitrary dimensions on a continuous sheet, and more specifically, with a printing method capable of printing with an arbitrary printing length on a continuous sheet such as a web. , relates to a novel printing method that can be applied sequentially within the circumferential dimension of a plate cylinder in a rotary printing press.

Prior Art In a rotary printing press that performs printing by supplying a continuous sheet between a plate cylinder and an impression cylinder to which a curved printing plate is attached, the size of the printed matter applied to the continuous sheet is generally determined by the circle of the plate cylinder. Determined by circumference.
In other words, it is impossible to print larger than the circumference of the plate cylinder, and if a plate smaller than the circumference is used, a blank space is created between prints each time the plate cylinder rotates, which is extremely wasteful. There are drawbacks.

In order to deal with this drawback, an all-size rotary press has been proposed in which the supplied continuous sheet is cut into sheets of appropriate size using a cutting device before printing, and printing is performed using a plate surface corresponding to the paper size. ,
This is unsuitable for high speed printing. Furthermore, since this method is based on the premise of cutting during printing, it goes without saying that it cannot be said to print on continuous sheets.

Therefore, as another means of printing in arbitrary dimensions without cutting the continuous sheet, it is conceivable to prepare a plate cylinder having a circumferential dimension corresponding to the desired printing dimension and to replace it each time. However, in this case, a large number of plate cylinders with different circumferential dimensions must be prepared as many as the desired printing size, which is extremely difficult to realize in terms of equipment costs and space for storing the plate cylinders. In this way, in rotary printing on continuous sheets, the circumferential dimension of the plate cylinder generally determines the printing length of the printed material, so it is not possible to sequentially print on continuous sheets with arbitrary dimensions and without creating unnecessary margins. It was difficult.

Problems to be Solved by the Invention However, there has long been a desire in the industrial world to perform high-speed printing on webs or other continuous sheets at arbitrary print lengths without cutting them. For example, in a corrugator line that continuously produces corrugated cardboard, a core paper made of a long continuous sheet and a liner are used, and the liner is glued to the top of the corrugated corrugation attached to the core paper. The company manufactures single-sided corrugated cardboard and double-sided corrugated cardboard.
However, printing on the obtained corrugated board is performed after cutting the corrugated board into a predetermined size to produce sheet-fed corrugated board. By the way, taking the front corrugated board as an example, as shown in Fig. 1, the front liner 10
The front liner 10 and the back liner 12 are joined to each other by a corrugated core paper 14, and the front liner 10 and the back liner 12 are approximately flat in appearance. However, each liner has a portion a that is supported by the corrugated top portion (so-called peak portion) of the corrugated paper and a so-called valley portion b that is not supported by the corrugated top portion. The pressure applied to the liner is uneven, which tends to cause dark flames and uneven coloring. In addition, if after forming corrugated cardboard, it is passed through a printing machine and compressed by a plate cylinder and an impression cylinder, there is a concern that the compressive strength of the corrugated cardboard itself will decrease. In order to perform printing, it is preferable to print on the liner in a continuous sheet before being laminated to the core paper. However, apart from the case where printing is performed according to the circumferential dimension of the plate cylinder as a repeating wood grain pattern (for example, in the Hinotsky machine), it is impossible to print on the liner at high speed without creating a margin with an arbitrary printing length. This was previously impossible, and its realization has been long awaited. Further, if the liner in sheet form is printed, the above-mentioned concerns such as a decrease in the compressive strength of the corrugated board itself will be eliminated, which is also desirable from this point of view.

Purpose of the Invention The present invention was devised in view of the above-mentioned drawbacks inherent in the prior art, and it is an object of the present invention to perform printing at an arbitrary printing length in a continuous state without cutting a web or other continuous sheet. To provide a printing method capable of printing without creating wasteful margins between adjacent printed matter.

Means for Solving the Problems In order to achieve this object, the present invention provides two or more plate cylinders at required intervals along the feeding direction of the sheet when printing on a continuous sheet, and each plate cylinder The printing is divided into sections to be printed on the continuous sheet, and each of these plate cylinders is rotated in synchronization with the feeding speed of the continuous sheet during printing, and after printing in the section to be printed is completed, The present invention is characterized in that the rotation of the plate cylinder is controlled at an inconstant speed during the rotation period of the plate cylinder until the printing of the next scheduled printing section is started.

Embodiments Next, a continuous sheet printing method according to the present invention will be described below with reference to preferred embodiments and the accompanying drawings. As an example, it will be explained in relation to a corrugator line that manufactures corrugated cardboard.
It goes without saying that the present invention is not limited to this, but can be widely applied to printing of webs such as general paper rolls, resin films, and other continuous sheets.

(Regarding the case of printing with one plate cylinder) The printing method according to the embodiment is carried out using two or more transfer printing machines as described later, but for convenience of explanation, the printing mode will be described as follows. We will discuss the case where the process is carried out using one transfer printing machine. In addition,
When the dimension L in the machine direction of the printed material (this is distinguished from the printing length l printed by the printing plate) is larger than the circumferential dimension πD of the plate cylinder (L>πD), and when it is smaller (L≦πD) ), the printing mode changes depending on the printing mode, so FIG. 2 illustrates a case where the dimension L of the printed material is smaller than the circumferential dimension πD of the plate cylinder (L<πD).

That is, FIG. 2 shows each mode in the intermittent states 1 to 7 when printing is performed by the printing method according to the embodiment. In the figure, the reference numeral 16 indicates the plate cylinder of the transfer printing machine, and the reference numeral 18 indicates the printing plate attached to the printing cylinder 16, and the arcuate dimensions of the printing plate 18 are as follows:
It is assumed that the circumferential dimension πD of the plate cylinder 16 is set to 1/4. Further, reference numeral 20 indicates a continuous sheet to be printed, and the planar state of the continuous sheet 20 is shown below in a positionally corresponding manner. In the plan view of the continuous sheet 20, each section A, B, C, etc. divided by vertical lines is an area where printing is planned (by printing, printed matter
A ₁ , B ₁ , C _{1 .} . .), and the dimension L in the flow direction indicated by the arrow is smaller than the circumferential dimension πD of the plate cylinder 16. Note that the impression cylinder corresponding to the plate cylinder 16 is omitted in the drawing.

The continuous sheet 20 is fed and running at a constant speed in the direction of the arrow, and is sequentially printed in each of the above-mentioned printing areas A, B, C, etc. with an arbitrary printing length l as shown in FIG. In order to perform this (the printing length l approximately matches the arcuate dimension of the plate surface 18 and is limited within the range of the circumferential dimension πD of the plate cylinder 16), the rotation speed per rotation of the plate cylinder 16 is Control may be performed according to the mode shown in FIG. Figures 3a and 3
Figure b shows the operating mode of the printing 18 on the plate cylinder 16, where the symbol v indicates a constant feeding speed of the continuous sheet 20, and the symbol vt indicates the maximum speed of the plate cylinder 16 (print surface 18).

That is, since there is a precondition that the dimension L of the planned printing areas A, B, C, ... is smaller than the circumferential dimension πD of the plate cylinder 16, printing is performed within the dimension L by one rotation of the plate cylinder 16. In this case, the rotation speed per rotation of the plate cylinder 16 must not be constant, and the rotation speed per rotation of the plate cylinder 16 must not be constant;
It is necessary to change the operating mode shown in FIG. 3A or FIG. 3B. For example, in FIG. 2, the rotation of the plate cylinder 16 is from the time (2) when the print 18 contacts the sheet 20 and starts printing to the time (3) when printing is completed and the print 18 leaves the sheet 20. The speed must be synchronized with the constant supply speed v of the continuous sheet 20 (horizontal section α in Figures 3a and 3b), and after printing is completed until printing starts in the next printing area B (4 to 3). 6) is controlled to accelerate and decelerate as indicated by β and γ in FIG. 3a, so that the printing plate 18 arrives at a speed greater than the synchronous speed v until the next printing start point. Further, as shown in FIG. 3b, the degree of acceleration and deceleration may be increased, and a flat portion rotating at the maximum speed vt may be interposed therebetween. In this case, the required acceleration is greater in the mode shown in FIG. 3b than in the mode shown in FIG. 3a.

Also, the dimensions L of the planned printing areas A, B, C,...
is larger than the circumferential dimension πD of the plate cylinder 16 (L>
πD), the rotation of the plate cylinder 16 may be controlled in the operating mode shown in FIGS. 4a or 4b (however, the printing length l is smaller than the circumferential dimension πD. In either case, during printing from the start of printing to the end of printing, the continuous sheet 2
The plate cylinder 16 rotates in synchronization with a constant supply speed v of 0, and during other periods, deceleration/acceleration control is performed at a speed smaller than the synchronized speed v, and the next printing scheduled section B starts printing. You will have to buy time until you arrive at your location.

In the operation mode shown in FIG. 4b, after waiting for a predetermined stop time, the synchronous speed v
The synchronous speed v is reached by accelerating at a speed smaller than .

In this way, the plate cylinder 16 is
In order to perform speed conversion to achieve the operation mode shown in the figure (for L < πD) or Figure 4 (for L>πD), it is necessary to perform pulse control on the pulse motor or use a DC servo motor as described later. This can be easily realized by controlling the motor with a D/A conversion circuit or variable speed control of an AC motor with an inverter.

(Regarding the case of printing with two or more plate cylinders) By the way, in order to simply explain the theory of the printing method according to the present invention, FIG.
Although we have given an example of printing on plate cylinder 1, in reality, plate cylinder 1
It is often difficult (though not impossible) to control the speed with just the base. The reason is, for example, in Figure 2,
As mentioned above, the printing plate 18 having an arc length of 1/4 of the circumferential dimension πD of the plate cylinder 16 is used, but in this case, the plate cylinder 16 has a continuous sheet for only 1/4 of the circumference. 2
The plate cylinder rotates in synchronization with the supply speed v of 0, and the subsequent 3/4 circumferential distance must be controlled to accelerate and decelerate within a short time at a speed greater than the synchronous speed v. 16 is itself quite heavy and has inherent inertia, so it is generally difficult to control the speed with only one plate cylinder.

Therefore, in the printing method according to the present invention, at least two plate cylinders are provided and these plate cylinders are set to share the printing of every other printing section, thereby providing sufficient response to each plate cylinder. It gives you time and allows you to easily handle continuous printing. For example, in FIG. 5, two plate cylinders 16a and 16b are arranged at a predetermined interval, and the plate cylinder 16a is responsible for printing every other printing section in the order of printing sections A, C, E,...
Further, the plate cylinder 16b has printing sections B, D, F,...
Similarly, the printing of every other item is shared in this order. If this is explained in the order of 1 to 8 in Fig. 5, the plate cylinder 1
6a starts rotating and printing in printing section A is completed (1-4), plate cylinder 16b starts rotating (5) and printing in printing section B is performed. At this time, the plate cylinder 16a shares printing in the adjacent printing section C.

From then on, the two plate cylinders 16a and 16b are
A similar variable speed control is provided, with every other printing section being shared with each successively arriving print section. In this way, in the embodiment shown in FIG.
One printing cylinder 16 had to perform printing for each printing section, and the control density of acceleration and deceleration per unit time was extremely high. However, in the embodiment shown in FIG. The plate cylinders only need to correspond to every other printing section, and assuming that the feed rate of the continuous sheet 20 is the same in both embodiments, the print preparation time for each plate cylinder is doubled, and therefore the acceleration/deceleration control You will be able to do this easily and with sufficient margin.

(Regarding an example of application in a corrugator line) An example of the case where the printing method according to the present invention is implemented in a transfer printing machine (hereinafter referred to as a preprint device) in a corrugator line for manufacturing corrugated board is shown in Fig. 6. . FIG. 6 shows an example in which the preprinting device 22 is installed in a double back section for producing double-sided corrugated boards, and the first single-sided corrugated board 2
4 and the second single-sided corrugated board 26 are transported on a conveyor 36, and the liner 28 is transported on the two plate cylinders 3.
2. When passing through the preprint device 22 equipped with the impression cylinder 34, printing is performed with a printing length of arbitrary size. Next, the first and second single-sided cardboard boxes 24, 26
passes through a triplex heater 30 for preheating and humidity control, merges with the printed liner 28 in a glue machine 38 to be glued, and is heated and pressed in a heating section 40 consisting of a heating box or hot plate. be done.

(Regarding the case of printing on continuous corrugated board) Furthermore, since the method of the present invention allows printing of any printing length on a continuous sheet, it is possible to print on the front liner of the continuous corrugated board after manufacturing it. It's okay. For example, in FIG. 7, after the continuous corrugated board 42 passes through the double facer 44 and before entering the slit scorer device 46, printing is performed with a preprinting device 22 of an arbitrary size by the preprint device 22 installed here. In this case, the continuous corrugated board 42 that has undergone predetermined printing via the preprint device 22 is subjected to predetermined slit processing and ruled line processing in a slit scorer device 46 that operates synchronously corresponding to the printed sections. The paper is cut into corrugated cardboard sheets of a predetermined length by cutters 48 that synchronize with each other.

(Regarding means for controlling the motor that drives the plate cylinder) Next, the means for controlling the motor for driving the plate cylinder, which is necessary to carry out the printing method according to the present invention, will be described. FIG. 8 shows one embodiment of the control circuit.
This uses a thyristor to accelerate and decelerate the DC motor M that drives the plate cylinder 32.
A pulse generator PLG ₁ is connected to the DC motor M,
Further, on the supply side of the continuous sheet 20, a pulse generator PPLG ₂ is connected to a measuring roll 50 that rotates in contact with the measuring roll 50. Directly below the plate cylinder 32, a sensor (for example, a magnetic sensor) 52 is arranged to detect the bottom dead center, that is, to detect the printing start point. The arithmetic circuit indicated by the reference numeral 54 includes a pulse generator PLG ₁
The rotation pulse △B of the motor M due to the supply pulse △ of the continuous sheet 28 due to the pulse generator PLG ₂
A is input. In addition, the circumferential dimension πD of the plate cylinder 32,
The length L of the section to be printed (see FIG. 2) and the maximum acceleration vt of the plate cylinder 32 are input to the arithmetic circuit 54 as data.

Line pulse △A from pulse generator PLG ₂ is
After the pulse is corrected, it is detected as the sheet feeding speed v, and is inputted to the plate cylinder speed control circuit 58 via the D/A converter 56. The detected speed v is input and stored in the memory 60 on the one hand, and on the other hand, fluctuations in the line speed are calculated and inputted to the control circuit 58 via the D/A converter 62. In addition, the difference between the length L of the section to be printed and the circumferential dimension πD of the plate cylinder 32, the pulse-corrected line pulse ΔA and motor rotation pulse ΔB, and the signal from the bottom dead center detection sensor 52 are added together. The data is preset in the integrator 64, passed through the limiter 66 and the D/A converter 68, and is inputted to the control circuit 58 as remaining length data up to the next printing start position.

Furthermore, the pulse-corrected line pulse ΔA and motor rotation pulse ΔB are added and integrated to take the absolute value, and the length L of the section to be printed is determined.
The absolute value of the difference between and the circumferential dimension πD of the plate cylinder 32 |L−
πD| is compared and entered into the speed command generator 70.
Further, the difference (vt- _v1 ) between the maximum acceleration vt of the plate cylinder 32 and the line speed v1 stored in the memory 60 is also inputted to the _speed command generator 70, and the calculated output is D/A converted. The rotational speed of the plate cylinder 32 is inputted to the control circuit 58 through the device 72 as the corrected rotational speed of the plate cylinder 32. In addition,
The speed command generator 70 determines whether the length L of the section to be printed is larger or smaller than the circumferential dimension πD of the plate cylinder 32, and, via the switching gate 74, sets the acceleration direction to be positive or negative. These commands are also given to the control circuit 58.

Based on these input data, the plate cylinder speed control circuit 58 causes the thyristor 76 to
DC motor M in the operating mode shown in Fig.
The printing method according to the present invention is preferably carried out by performing acceleration/deceleration control. Note that this control means is
This is merely an example, and other
Various control circuits can be employed, such as controlling the rotational speed of an AC motor using a transistor inverter using PWM (pulse width modulation).

Effects of the Invention As explained above, according to the printing method according to the present invention, when printing on a continuous sheet, two or more plate cylinders are provided, and when printing, these plate cylinders are used to supply the continuous sheet. By rotating in synchronization with the printing speed and controlling the speed and deceleration of the rotation period of the plate cylinder from the end of printing until the start of the next printing, each plate cylinder can print the portion to be printed in each section on a continuous sheet. can be done. In other words, it is possible to print at a desired printing length without cutting the continuous sheet while it is still in a continuous state (this arbitrary printing length is determined by the printing length attached to the plate cylinder, and therefore the printing length (Of course, it is limited within the circumferential dimension of the cylinder), and has many beneficial effects, such as eliminating unnecessary blank space between adjacent printed matter. Therefore, the method of the present invention is preferably used for printing continuous liners in corrugator lines for manufacturing corrugated board, but also for printing on continuous liners.
It can be widely applied to printing long films, fabrics, webs, etc. at arbitrary printing lengths.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a double-sided corrugated board, Fig. 2 is a schematic explanatory diagram of the printing process for explaining the theory of the printing method according to the present invention, and Figs. 3a and 3b show the length L of the section to be printed. , the circumference dimension of the plate cylinder πD
4a and 4b are schematic diagrams showing the operation mode of the plate cylinder when L>πD is smaller than (L<πD),
FIG. 5 is a schematic explanatory diagram of the printing process when implementing the printing method according to the present invention, and FIGS. 6 and 7 show a blurprinting device installed in a corrugator line for implementing the printing method according to the present invention. FIG. 8 shows a block diagram as an embodiment of a motor control circuit for carrying out the printing method according to the present invention.

Claims (1)

[Scope of Claims] 1. When printing on a continuous sheet, two or more printing cylinders are provided at required intervals along the feeding direction of the sheet, and each printing cylinder is used to print on each section of the continuous sheet to be printed. During printing, each of these plate cylinders is rotated in synchronization with the feeding speed of continuous sheets, and after the printing of the section to be printed is completed, printing of the next section to be printed is started. A continuous sheet printing method characterized by performing non-uniform speed rotation control over the rotation section of the plate cylinder until the plate cylinder rotates.