JPH0247063A - Device for automatic cleaning of blanket cylinder - Google Patents

Abstract

PURPOSE:To rapidly automatically detect the completion of cleaning by detecting the variation in the lightness on the surface of a web moving in a printer during cleaning work by a sheet face lightness sensor, completing the cleaning when the lightness arrives at a predetermined value, and outputting a cleaning end designation signal. CONSTITUTION:Cleaning cloth 8 is disposed at an opposite position to a blanket cylinder 2 by a clothe feeding cylinder 14, a cloth feeding arm 16, etc. The cloth 8 which is moistened with cleanser is pressed to the cylinder 2 by a pressure pad 12, and starts cleaning. In this case, cleaning completion detecting means is operated, and the variation in the lightness of a printing sheet 18 is detected by a sheet face lightness sensor 20. As the cleaning is advanced, the lightness is raised, and when it arrives at a reference level, an AND circuit 24H outputs a cleaning end designation signal, and the pad 12 stops pressing of the cloth 8, and winds the cloth 8 at a predetermined amount.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an automatic plunket cylinder cleaning device, and in particular,
The present invention relates to cleaning completion detection means for reducing wastage of cleaning cloth, cleaning liquid, and printing paper.

[Conventional technology]

In conventional blanket cylinder cleaning devices, the cleaning process is automated, but the cleaning results are not checked.

That is, the number of times of washing that is estimated to be sufficient is set in advance, and when the number of times of washing is reached, the washing is finished.

[Problem to be solved by the invention]

As a result, printing may be resumed before the dirt has been completely cleaned, or conversely, cleaning may continue even after the dirt has been sufficiently removed, resulting in the problem of wasting cleaning cloth, cleaning liquid, and printing paper. there were.

Therefore, a Puno method has been proposed in which several types of cleaning times are set in advance and selected depending on the condition of the printed matter during use.

However, with this type of method, it is time-consuming as the predictions are wrong and it becomes necessary to clean again, and there is a tendency to set a large number of times. It wasn't a cleaning device.

SUMMARY OF THE INVENTION An object of the present invention is to provide an automatic blanket cylinder cleaning device equipped with a cleaning completion detection means that can accurately detect the completion of cleaning and reduce wastage of cleaning cloth, cleaning liquid, and printing paper to a large extent.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a paper surface brightness sensor that non-contactly detects changes in the brightness of the surface of a web running in the printing press during cleaning work in a blanket cylinder cleaning device for an offset printing press. The present invention proposes an automatic blanket cylinder cleaning device that includes a circuit that determines that cleaning is complete when the brightness reaches a predetermined value, and that has a cleaning completion detection means that outputs a cleaning completion instruction signal to a cleaning unit.

Blanket cylinder cleaning completion detection means are generally provided on both the front and back sides of the printing paper.

Furthermore, in the case of multi-color printing, basically it is sufficient to provide it after the final printing unit, but it is also possible to provide it for each color printing unit.

[Operation] Generally, during the blanket cylinder cleaning operation, a portion of the ink stains on the surface of the blanket cylinder softened by the cleaning liquid adheres to the running web and is carried away. The brightness of the web surface corresponds to the degree of lr3 deviation on the surface of the blanket cylinder, and as the lr3 deviation of the blanket cylinder surface decreases as cleaning progresses, the brightness of the web surface increases.

Therefore, in the present invention, the disappearance of the '/Q deviation of the web that is run during cleaning is detected non-contactly, that is, optically, as a change in brightness, so there is no need to estimate or set the required number of cleanings. Become.

In addition, conventionally it took the same amount of time to clean both items with little dirt and items with a lot of dirt, but with the present invention, the completion of cleaning is detected early on for items with little dirt, so the cleaning work can be completed in a short time and the next time. Start printing and preparing for printing.

On the other hand, heavily soiled items can be reliably cleaned without requiring repeated instructions for re-cleaning.

As a result, wastage of cleaning cloth, cleaning fluid and printing paper is f
The low installation costs of the simple device of the present invention can be recovered in a short period of time, and then in the long term, significantly reducing running costs.

〔Example〕

Next, an embodiment of the present invention will be described with reference to the drawings.

1 and 2 are a perspective view and a side sectional view showing an embodiment of an automatic blanket cylinder cleaning device equipped with a blanket cylinder cleaning completion detection means according to the present invention.

In these figures, 2 is the blanket cylinder to be cleaned;
4 is a cloth supply roll of the cleaning unit; 6 is a cloth take-up roll; 8 is a cleaning cloth sent between the two rolls; 10 is a spray bar that supplies cleaning liquid to the cleaning cloth 8; a spray bar 112 is used to transfer the cleaning cloth 8 to the blanket cylinder during cleaning; 1 is a pressure roller that presses on 2, 14 is a cloth feed cylinder, 16 is a cloth feed arm,
18 is printing paper.

In the present invention, an elliptical detection area 22 located approximately at the center of the printing paper 18 is focused on the basic configuration of such an automatic blanket cylinder cleaning device.

A paper surface brightness sensor 20 that optically detects changes in the brightness of the surface of the printing paper 18, and a cleaning completion determination circuit 24 that determines that cleaning is complete when the brightness reaches a predetermined value based on the output thereof are provided. .

As the paper surface brightness sensor 20, various photoconductive elements such as a photodiode, a phototransistor, and a CCD can be used.

Generally, when feeding printing paper of various widths, it is desirable to set the detection area 22 of the paper surface brightness sensor 20 near the extension line of the horizontal center of the blanket cylinder 2, since the paper is fed based on the horizontal center of the blanket cylinder 2.

Further, the cleaning completion determination circuit 24 includes comparators 24A to 24D and a detection level setter 2, as shown in FIG.
4E and an AND circuit 24F-II. Comparators 24A and 24B, which take in signals from the upper paper brightness sensors 2OA and 2OA, are connected to detection level setters 24. The reference level of the washed paper surface brightness set according to the ground color of the paper surface by E is compared with the signal from the paper surface brightness sensors 2OA and B, and when this signal exceeds the reference level, the upper blanket cylinder 2 It is determined that cleaning has been completed. The AND circuit 24F determines that the entire surface of the upper blanket cylinder 2 has been completely cleaned when the respective comparators 24A and 24B determine that cleaning has been completed. Comparators 24C and D and A for the lower printing side
The operation of the ND circuit 24G is similar, and determines whether the lower blanket cylinder 2 has been cleaned. The signals from the AND circuits 24F and 24G are further applied to an AND circuit 24I to determine that cleaning of the upper and lower blanket cylinders 2 is complete.

Now, the operation of the automatic blanket cylinder cleaning apparatus of the present invention having such a configuration will be explained with reference to FIG.

When blanket cylinder cleaning is started in accordance with an instruction from a control panel (not shown), cleaning liquid is sprayed onto the cleaning cloth 8 from the spray bar 10, as shown in (A).

Next, as shown in (B), the cleaning cloth 8 is fed by the cloth feeding cylinder 14 and the cloth feeding arm 16 shown in FIG.

Here, the cleaning cloth 8 moistened with the cleaning liquid is pressed against the blanket cylinder 2 by the pressure pad 12 to start cleaning. At this time, the cleaning completion detection means is activated, and the paper surface brightness sensor 20 detects a change in the brightness of the printing paper 18. Initially, 1. Since the surface of the blanket cylinder 2 is dirty with ink, the brightness of the surface of the printing paper 18 is low;
As the cleaning progresses, the brightness increases until it reaches a standard level indicating that it is clean.

Therefore, a cleaning end instruction signal is output from the AND circuit 24H, and the pressure pad 12 stops pressing the cleaning cloth 8, and as shown in (D), the cleaning cloth 8 is wound up by a predetermined amount and the cleaning cloth 8 is retracted for the next cleaning. .

In the above embodiment, the completion of cleaning of both the upper and lower blanket cylinders 2 is detected, but it is also possible to adopt a method of detecting the completion of cleaning of only one blanket cylinder 2.

In addition, in the case of multi-color printing, the object of the present invention can be achieved by providing a cleaning completion detection means after the final blanket cylinder 2, but if it is provided for each printing unit of each color, the cleaning cloth and cleaning liquid of each stage will be It is possible to keep consumption to a minimum.

Furthermore, instead of detecting changes in the brightness of the web 18,
Changes in the surface of the blanket cylinder 2 itself may also be detected.

〔Effect of the invention〕

According to the present invention, since the completion of cleaning can be automatically detected quickly and accurately, the waste of cleaning cloths, washing cloths, cleaning cloths, printing materials, and abrasives is drastically reduced.

Further, since the cleaning completion detection means of the present invention has a simple configuration, its low installation cost can be recovered in a short period of time, and thereafter, the running cost can be significantly reduced over a long period of time.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of an automatic plunger barrel cleaning device equipped with a plunger 1 to barrel cleaning completion detection means according to the present invention, FIG. 2 is a side sectional view thereof, and FIG. 3 is an explanation of the cleaning procedure. It is a diagram. 2. Planken 1 to body, 4. Cloth supply roll, 6
Cloth winding roll, 8..Cleaning cloth, 10.Spray bar 512..Pressure pad. 14... Cloth feed cylinder, 16... Cloth feed arm,
18... Web, 2o mountain paper surface brightness sensor, 2
2...Detection area, 24...Cleaning completion determination circuit, 24A-D...Comparator, 24E...Detection level setter, 24F-H...AND circuit.

Claims (1)

[Scope of Claims] 1. A blanket cylinder cleaning device for an offset printing press, comprising: a paper surface brightness sensor that non-contact detects changes in the brightness of the surface of printing paper (web) running in the printing press during cleaning work; An automatic blanket cylinder cleaning device comprising a circuit for determining that the cleaning is completed when the brightness reaches a predetermined value, and cleaning completion detection means for outputting a cleaning completion instruction signal to a cleaning unit.