JPS61266249A - Doubling preventive device of press - Google Patents

Abstract

PURPOSE:To automatically carry out the braking control for prevention of doubling and to achieve the role of the auxiliary brake of press removing the loss of power, by a method wherein a motor is connected to the shaft of the plate cylinder of press and a controller is provided to the motor. CONSTITUTION:A plate cylinder 1 comes in contact with a blanket cylinder 2. The blanket cylinder 2 is driven via gears 15, 14, 13 and the plate cylinder 1 is driven with the gears 13 via the gear 12. Further, the motor 3 capable of regenerative braking is connected to the plate cylinder 1 via gears 11, 12 and the motor 3 is connected to a power source 5 via a controller 4. The torque of the motor 3, that is, the torque in the reversing direction to the arrowed mark A is transmitted to the gear 12 via the gear 11 and the gear 12 is not moved between the back lash to the gear 13. Because the driving side tooth surface of gears 12, 13 come always in contact with each other and the plate cylinder 1 and the blanket cylinder 2 are rotated without sliding during operation, the doubling is not generated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an overlapping prevention device for an offset printing press.

(Prior Art) In an offset printing press, ink supplied to the printing area of a printing plate cylinder is once transferred onto a blanket cylinder, and then printing is performed from the blanket cylinder onto a paper surface.

If we focus on one point on the plate, and a shift occurs between the blanket cylinder and the plate cylinder due to gear backlash while this point is in contact with the blanket cylinder, the point will change according to the amount of shift. Stretching of the shape occurs. Furthermore, when this point contacts again after one rotation of the blanket cylinder, when it comes into contact with a point that deviates from the previous contact history due to similar slippage, the point is stretched or two points are printed on the paper surface. Generally, such printing failures are called double prints, and appear as uneven color tones on printed matter.

The outside diameter dimensions of the blanket cylinder and the plate cylinder are typically in an integer ratio of 1:1 or 2:1, and the plate cylinder is driven from the blanket cylinder by the outside diameter of the cylinder or by a gear, and the outside diameter of the cylinder is driven by the outside diameter of the cylinder. In some cases, the gear acts as a brake, and in cases where the gear is driven, the outer diameter of the cylinder acts as a brake, and constant rotational contact is always performed, but in reality, the rotation is caused by the passage of a calling roller, gap, etc. There are many elements of rotational fluctuation in a printing press, and the torque required to drive the plate cylinder is
It is changing from moment to moment. When printing is performed normally from the plate cylinder gear seen from the gear on the blanket cylinder side, positive or negative torque is acting without reversal, but until torque fluctuation causes torque reversal. When it reaches that point, it appears as an overlapping effect as mentioned earlier.

In general, in printing presses, the absolute value of the torque that drives the plate cylinder is small, and the fluctuation value often exceeds the absolute value, causing overlapping. Therefore, it is necessary to apply a mechanical brake torque to the plate cylinder to drive the plate cylinder. Measures were taken to increase the absolute value of torque.

(Problems to be Solved by the Invention) As described above, when applying mechanical brake torque to prevent overlapping, heat generated by the brake is generated inside the machine, so a cooling device is required. Additionally, the energy required for the brakes results in power loss for the printing press. Additionally, mechanical brakes have the problem of being difficult to perform various effective controls.

(Means for Solving the Problems) The present invention addresses the above problems, and includes an electric motor connected to the shaft of the plate cylinder of a printing press L2, and a control device for controlling the electric motor. The present invention relates to a doubling prevention device for a printing press, which is characterized in that it is capable of automatically performing braking control for doubling prevention. It also eliminates power loss and can serve as an auxiliary brake for machinery. Another object of the present invention is to provide an overlapping prevention device for a printing press that can eliminate the need for a cooling device and reduce power loss.

(Embodiment) Next, the overlapping prevention device for a printing press of the present invention will be explained using an embodiment shown in FIG.
) is in contact with the blanket cylinder (2). Gear 0 0
The blanket cylinder (2) is driven by the gear 0, and the plate cylinder (11) is driven by the gear 0 through the gear A. Also, the electric motor (3) capable of regenerative braking is driven by the gear Q1.
The electric motor (3) is connected to the power supply (5) via the control device (4).

Note that the electric motor (3) may be directly connected to the shaft (1α)' of the plate cylinder without intervening the gear Q1)Q21.

(Function) Next, the function of the overlapping prevention device of the printing press will be explained.
When a power source (not shown) is driven, gears a (14) (1)
303, the blanket cylinder (2) and plate cylinder (1) rotate in the direction of arrow tc+(B), and at the same time, the regenerative braking electric motor (3) rotates in the direction of arrow (A) through gear (11). Rotate. Also, when power is supplied from the power source (5) to the electric motor (3) via the control device (4), the IT electric motor 3)
It rotates in the direction of arrow fAl while generating a rotational force in the opposite direction. That is, the electric motor (3) becomes a load, generates electric power corresponding to that amount, and sends it back to the power source (5).

The rotational force of the electric motor (3) (rotational force in the opposite direction to the arrow (A)) is transmitted to the gear (+21) via the gear 01), and the gear I moves between backlashes with respect to the gear a4. Since the driving side tooth surfaces of the gear (the gear is always 0 during operation) come into contact with each other and the plate cylinder (1) and blanket cylinder (2) rotate without slipping, no overlap occurs.

Further, the heat generated during braking is generated from the loss of the electric motor (3) as an electric machine, and is much smaller than the heat for braking, and does not require a special cooling device.

Further, the braking force can be easily and automatically controlled according to changes in torque fluctuations of the plate cylinder (1) and the blanket cylinder (2), operating speed, etc. Also, the plate cylinder (1) is the blanket cylinder (2).
In machines driven by the outer periphery of the electric motor (
3) Overlapping can also be prevented by applying torque in the driving direction of the machine.

Further, when the machine is stopped, the electric motor (3) can be operated as an auxiliary brake without power loss. In addition, it can be used as a slippage device without power loss in machines that require a brake for sudden stops.

Note that even if the electric motor (3) is capable of dynamic braking, the effects other than power loss are the same.

(Effects of the Invention) As described above, the present invention connects the electric motor to the shaft of the plate cylinder of the printing press, and the electric motor is provided with a control device for controlling the electric motor, so that the braking control for preventing overlapping is performed. It can be done automatically. It also eliminates power loss and can serve as an auxiliary brake for machinery.

Additionally, a cooling device is not required, which has the effect of reducing power loss. Note that when an electric motor capable of dynamic braking is used, the same effect is achieved except for power loss.

Although the present invention has been described above with reference to embodiments, it goes without saying that the present invention is not limited to such embodiments, and that various design modifications can be made without departing from the spirit of the present invention. 1゜

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the overlapping prevention device for a printing press according to the present invention. (1)...Plate cylinder, (3)...Electric motor, (4)...
Control device. Sub-agent: Patent attorney: Shige Okamoto, 2 other people

Claims (1)

[Claims] An overlapping prevention device for a printing press, characterized in that an electric motor is connected to the shaft of a plate cylinder of the printing press, and the electric motor is provided with a control device for controlling the electric motor.