JP4457433B2 - Blanket dirt prevention device and blanket dirt prevention method using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an anti-blocking powder blanket anti-stain device in an offset printing sheet machine and a blanket anti-stain method using the device.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in an offset printing sheet feeder, printing sheets that have been printed are transported to a paper discharge unit and stacked. If ink drying is not complete at this time, a show-through state in which ink movement occurs between stacked printing papers may occur. In order to prevent this show-through, that is, blocking, blocking prevention powder is sprayed on the surface of the printing paper in front of the paper discharge unit. In front of the paper discharge unit, blocking powder is supplied to the printing paper from the powder spraying nozzle, but not all the powder sprayed from the nozzle is placed on the printing paper, and surplus powder is generated. In the conventional method, this excess powder is collected by the upper dust collector of the paper discharge unit. However, the dust collector is not able to collect all the excess powder, and there are powders that flow out of the printing press and remain in the printing press. As proposed in Japanese Utility Model Laid-Open No. 01-16331, etc., attempts have been made in the past not to generate excessive powder as much as possible outside or inside. However, it is difficult to completely prevent the generation of excess powder, and there is no precedent for countermeasures against powder backflow to the printing unit upstream of the printing press.
[0003]
[Problems to be solved by the invention]
The present invention has been made in view of the above problems, and prevents blocking powder sprayed in front of the paper discharge unit from being scattered back to the outside of the printing press and inside the printing unit upstream of the printing press. It aims at proposing the blanket dirt prevention apparatus and the blanket dirt prevention method using the apparatus.
[0004]
[Means for Solving the Problems]
In order to solve the above problem, the invention according to claim 1
In the offset sheet-fed machine, in order to prevent backflow of the blocking prevention powder sequentially from the downstream side of the conveyance path to the printing unit side conveyance path in the printing paper run-up section before the paper discharge section in the middle of the conveyance path of the printing paper. A blanket antifouling device comprising an air injection device, a powder reservoir, a blower in the vicinity of a run-up portion and a block for circulating an anti-blocking powder accumulated in the powder reservoir, and a pipe line therefor.
[0005]
The invention according to claim 2
Use of the blanket antifouling device according to claim 1 to prevent blocking in the air jetting device provided in the printing unit side conveyance path of the printing paper run-up section in front of the paper discharge section in the middle of the printing paper conveyance path. Preventing backflow of the powder, collecting the anti-blocking powder collected in the vicinity of the run-up part and in the powder pool, together with the air in the circulation blower, and injecting the air together with the powder toward the downstream of the conveying path, A blanket smudge prevention method characterized by spraying onto printing paper in the vicinity of the paper discharge unit.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
An example of an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view of the blanket antifouling device of the present invention.
The run-up portion in front of the discharge unit of the printing press is blocked from the outside by the delivery guide 7, and the blocking preventing powder hardly flows out from this position. Actually, the powder injection is performed on the surface of the printing paper being conveyed from the powder spray nozzle 6. At this time, according to the above-described conventional method, excess powder is generated, and is deposited below the run-up portion. Therefore, a groove such as a powder reservoir 2 is provided as a collection place for the accumulated powder. In addition, the collected excess powder is jetted onto the printing paper being conveyed again by the blower 3 via the circulation path.
[0007]
In addition, for the powder which is not collected in the powder reservoir 2 and is going to flow backward, the backflow prevention air 1 is always jetted to prevent entry into the printing unit, thereby causing the printing unit blanket to become dirty. Can be minimized. At this time, the continuous operation by the backflow prevention air 1 and the dust collector 4 is indispensable, and the operation for reusing the powder by the blower 3 causes the fluttering of the conveyed printing paper regardless of the operation or stoppage of the printing press. It is desirable not to do so.
[0008]
The delivery guide 7 was manufactured by bending a cold rolled material. A commercially available blower (Fuji Electric: RING BLOW) is used as the circulation blower 3 for reusing the powder, and this is attached to the outside of the printing press via an inverter, and is connected to the run-up section in front of the paper discharge section. The spray was divided into routes. Further, the powder reservoir 2 is manufactured with a groove depth of 100 mm, and the air nozzle for backflow prevention is preferably non-diffusing air. Used by opening a part.
As for the printing press operation method at this time, the dust collector is always operating, the backflow prevention air is synchronized with the operation of the printing press, and the blower for reusing the powder is adjusted to 1/3 when the printing press is stopped. is doing. As a result, a good printing state could be maintained for a long time.
[0009]
【The invention's effect】
According to the present invention, it is possible to prevent the anti-blocking powder sprayed in front of the paper discharge unit inside and outside of the printing press from being scattered back to the printing unit upstream of the printing press, and thereby the dirt on the blanket. It became possible to prevent.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view of a blanket antifouling device of the present invention.
1 ... Air for preventing backflow 2 ... Powder pool 3 ... Blower 4 ... Dust collector 5 ... Delivery air blow 6 ... Powder spray 7 ... Delivery guide

Claims (2)

In the offset sheet-fed machine, in the middle of the conveyance path of the printing paper, in the printing unit side conveyance path of the printing paper run-up section in front of the paper discharge section, the powder reservoir disposed at the lower portion of the running-up section, and this powder collection An air injection device for preventing backflow of the blocking prevention powder that injects air from the printing unit side, and a circulation for circulating the blocking prevention powder accumulated in the vicinity of the run-up portion and in the powder pool and spraying it onto the printing paper Blanket dirt prevention device characterized by having a blower for air and its pipe line.   A blanket contamination prevention method for preventing a blanket of an offset sheet-fed machine from being contaminated by an anti-blocking powder using the blanket contamination prevention device according to claim 1.

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