JPH11320846A - Damage preventing device for printing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect a printing unit from being broken by executing an operation such as the detection of a tear in a printing material by a method wherein a controlling device for separating an impression cylinder from a paper after a certain fixed time lag is provided in other printing unit locating among printing units subsequent to a tear site. SOLUTION: Respective band-like matter tear sensors 7-14 are installed in printing units 1-6 so as to send a signal to the controlling device of a printing machine when a sensor recognizes a tear, resulting in letting the controlling device to actuate the controlling system of the printing machine by means of a stopping algorithm given in advance. When a tear develops before the first printing unit 1, the rotational frequencies of printing units 1, 3 and 5 or every other printing unit are controlled to become zero and mechatronics type brakes are put into actuation. The braking systems of printing units 2, 4 and 6 or every other printing unit are put into actuation after the elapse of a certain fixed period of time and the mechatronics type brakes of the printing units start their actuations after the elapse of a certain fixed period of time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for preventing breakage in a printing machine for printing a roll of paper, metal foil, textile, or other belt-shaped material.

[0002]

2. Description of the Related Art In order to prevent the printing substrate from being damaged in the printing unit of a printing press, currently known methods protect the printing unit by means of a device for catching, cutting or fixing the web material.

[0003] In DE-PS 41 30 679, the printing speed on a guide roll is measured by means of a pulse generator which is arranged immediately before and after one of the printing units and which is driven by a strip and which is driven by a belt-like material. Pulse values are compared by a connected control computer, and when the pulse values compared with each other deviate from a predetermined reference value, the printing press is stopped to prevent damage to the printing unit of the roll-type rotary printing press. A method of preventing this is disclosed.

According to this method, the response speed is reduced in order to avoid damage to the printing unit.

[0005]

However, this method has disadvantages such as technical complexity, large occupied space, and difficulty in printing operation due to the inability to realize optimum conditions for all paper rolls. There is. This is especially true for printing presses that use multiple paper rolls. Further, if the paper tears, there is a danger to the paper take-up roll, and the blanket, bearings, journals and, in extreme cases, the entire mechanism of the printing unit may be damaged. A stoppage of the folding machine or a stoppage of the drive system of the printing press due to the wrapping around the impression cylinder may make it impossible to stop the operation for a maximum of about one week, which corresponds to a decrease in the operation rate of about 2%. This adds to the cost of repair. In other known impression cylinder protection systems, the power supply is disconnected directly in the printing unit drive via split pins. For this reason, the drive wheel of the blanket cylinder is composed of two parts connected by two shear bolts, and when the drive system is overloaded by entanglement, the bolt is broken and the drive wheel runs idle. This prevents damage to the impression cylinder drive wheels and torsion of the impression cylinder journal.

[0006] It is therefore an object of the present invention to propose an apparatus for preventing the printing unit from being damaged by detecting a tear in the printing material.

[0007]

In the damage prevention device for a printing press according to the present invention, each of the printing units is provided with a rupture sensor for monitoring the rupture of the sheet, and the first printing unit after the rupture point of the sheet and the first printing unit. A control device is provided on the impression cylinders of every other printing unit which immediately releases the impression cylinders from the printing material, and the regenerative braking force of the first impression cylinder and every other impression cylinders after the tear point. A control device for separating the impression cylinder from the sheet after a certain time delay is provided in another printing unit located between the printing units after the tearing point, and a further control device. The printing unit before the tear point is
Thereafter, the rotation speed is controlled to zero by synchronizing the angle, speed, and position with the individually driven printing unit.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The apparatus according to the present invention will be described in more detail with reference to an embodiment. As shown in FIG. 1, in this embodiment, strip-like material tear sensors 7-14 are installed in the printing units 1 to 6, respectively, and when the sensors recognize the tear, a signal is sent to the printing press control device, and the control device preliminarily transmits the signal. The braking system of the printing press is activated according to the given stop algorithm. When a tear occurs before the first printing unit 1, control is performed so that the rotation speed of the printing units 1, 3, 5, 7, and every other printing unit thereafter becomes zero, and the mechatronic brake is activated. .
The braking systems of the printing units 2, 4, 6 and every other printing units are activated after a certain time, so that the mechatronic brakes of these printing units start operating after this certain time. By providing a time lag between the application of the braking command between two adjacent printing units, the tension of the web is significantly increased, and the web is ruptured. The printing unit before the rupture point is controlled to zero speed by a standard braking gradient, synchronizing the angle, speed and position with the subsequently individually driven units. This allows these units to be shut down without significant wear, and the majority of the paper remains in the press, making it easier for the print operator to restart the press and reducing downtime. Be shortened. The paper ejected after the first tear does not damage the printing unit during the subsequent braking process. The braking gradient usually varies from machine to machine and is determined by the maximum speed and the moment of inertia of the braked object. In addition, a paper cutting device is provided at the exit side of the last printing unit in order to prevent a double-winding of the reversing paper into the blanket cylinder due to a tear in front of the printing unit in the folder direction. The device is activated by the sensor 14 or any further sensors in the paper running direction. After the printing press is completely stopped, it is easy to remove the residual paper from the printing unit, and the band-shaped paper can be passed through the printing unit, passed through the printing unit to the position where the paper is maintained, and re-adhered. .

[0009]

In the damage prevention device for a printing press according to the present invention, the time difference between the activation of the brake command between two adjacent printing units causes the tension of the strip to increase significantly, leading to a tear. This can prevent the printing unit from being damaged.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a printing press and a control table showing an embodiment of the present invention.

[Explanation of symbols]

1, 2, 3, 4, 5, 6 printing unit 7, 8, 9, 10, 11, 12, 13, 14 tear sensor

Claims (1)

[Claims] 1. A damage prevention device for a printing press, comprising:
Each of the printing units (1-6) is provided with a tear sensor (7-14) for monitoring the tearing of the sheet, and the impression cylinders of the first printing unit after the tearing point of the sheet and every other printing unit thereafter. A control device for generating a regenerative braking force of the first impression cylinder after the tear point and every other impression cylinder thereafter, and a control device for immediately releasing the impression cylinder from the belt-shaped printing material is provided. A control unit for separating the impression cylinder from the sheet after a predetermined time delay is provided in another printing unit located between the printing units thereafter, and the printing unit before the tearing point is further controlled by another control unit. An apparatus for controlling the number of revolutions to zero by synchronizing an angle, a speed, and a position with a printing unit individually driven.