RECYCLING METHOD OF PRINTING BLANKET The Related Art

The invention relates to the blanket, which is used in printing sector in which printing is made by transferring offset or ink, and which provides transfer of ink to paper, metal, plastic etc. materials.

The invention particularly relates to the method of providing recycling and reuse of the blanket, which is used in printing sector, and which performs the task of taking the ink found on the printing block in a quick and correct way and transferring this ink to the printing material.

The Prior Art

Nowadays, among the printing techniques used, offset printing is the newest among the printing techniques. Offset printing technique is based on the principle of not mixing water and oil with each other. Three main printing components are found in offset printing presses. These are; the block cylinder which carries the printing block, the blanket which transfers the image to be printed from the block cylinder to the paper and which is generally made of rubber, and the printing cylinder which compresses the paper into the blanket.

When the press starts to operate, the block found in the block cylinder is firstly wetted by the stored water while passing through the wetting cylinders. While the stored water closes the surfaces which do not comprise image on the block and do not go into the press, it is refused by the regions going into the press. Block cylinder encounters the ink cylinders in the second phase. Ink containing oil in its structure does not get mixed up on the surfaces covered with aqueous solution; only accepted by the regions on which the image is found. Inked images are then transferred to the rubber blanket. Image found on the blanket is transferred to the paper in the last phase. Since the block used in the offset printing is very sensitive and the paper surface quickly wears out the block, direct printing on the paper can not be made from the block. Therefore, a rubber blanket is used between for

transferring the image to be printed. Since the rubber blanket extends the expected life of the printing block and can compress the paper more, quite well printing results can be obtained even with low quality papers.

As it would also be seen in the patent application no US3983287, generally, blankets formed of three or more layers are used. The rubber layer found at the upper surface of the blanket is the layer transferring the printing onto paper. This layer is the layer that is actually damaged.

The expected lives of the blankets are short in the prior art and they are junked after usage. In general, the surface of the blanket making printing in the printing machine is damaged due to the damage caused by the material printed. Since the printing surface being damaged reduces the printing quality, the blanket has to be renewed.

Surface of the printing blanket can be damaged as a result of sticking of papers on top of each other, crumpling of the paper, sticking of foreign substances on the paper, and the quality of the paper being low etc. reasons originating from the printing mechanism. The blankets may be out of use in a few days or a few months. At the end of this period, the blankets are junked.

The junked materials are the textile found at the bottom, the rubber covering found on it, and aluminium metal bars found at the edges. The said situation causes economic loss.

Even one part of the printing surfaces of the above said blankets is damaged; the blanket is separated for being junked. Brief Description of the Invention

The invention is formed by being inspired from the present situations and its purpose is to eliminate the above said drawbacks.

The invention is the method providing recycling and reuse of the printing blanket generally used in offset printing.

Purpose of the invention is to bring into use the blankets, which have completed their expected lives as a result of usage or which have to be dropped out of use as a result of damage, via the method of recycling. In this way, printing can be made in the same quality by using just a small percentage of the financial source required to buy a new blanket. Another purpose of the invention is to provide environmental protection by avoiding formation of waste material. The printing blanket has to be renewed as a result of the tiniest deformation on the printing surface reducing the quality of the printing. Another purpose of the invention is to increase the opportunity of competition since it provides economical recycling.

Since the invention provides more than one recycling opportunities, the money spent on blanket is reduced gradually at each recycle. For example, if annually 1.000.000 euro is spent on blanket, this amount will be reduced to 500.000 euro after the first recycle and to 300.000 euro after the second recycle.

The structural and characteristic features of the invention and all advantages will be understood better in detailed descriptions with the figures given below and with reference to the figures, and therefore, the assessment should be made taking into account the said figures and detailed explanations. Figures for Better Understanding of the Invention

Figure - 1 ; is the flow diagram of the basic process steps of the method, which is the subject of the invention, applied on lightly damaged blankets.

Figure - 2; is the flow diagram of the basic process steps of the method, which is the subject of the invention, applied on locally damaged blankets.

Figure -3; is the flow diagram of the basic process steps of the method, which is the subject of the invention, applied on completely damaged blankets.

Figure - 4; is the front section view of the blanket, on which the method of the invention is applied.

Drawings do not have to be scaled and details not necessary for understanding the present invention may be neglected. Moreover, components which are at least widely equal or which have at least widely equal functions are shown with the same number.

Description of the References

100. Blanket

101. Hard rubber

102. Adhesive layer

103. Soft rubber

104. Bottom layer

10. Grinding of the hard rubber layer found at the upper surface of the blanket

11. Measurement of the surface slickness of the hard rubber layer found at the upper surface of the blanket

12. Sanding of the hard rubber layer found on the blanket

13. Measurement of the surface sensitivity of the hard rubber layer found at the upper surface of the blanket

14. Separation of the blanket in order to be used in printing machines 20. Determination of the regions with local damage

21. Placement of rubber in the form of patch and made of the same material

22. Vulcanization of the blanket on which patch is placed

23. Mellowing of the blanket

30. Complete scraping of the hard rubber layer found at the upper part of the blanket

31. Making surface covering by the hard rubber paste

32. Vulcanization of the blanket on which covering is made

NBR : (Nitrile butadiene rubber)

EPDM : (Ethylene-Propylene-Diene - Monomer)

UV : Ultraviolet

Detailed Description of the Invention

In this detailed description, the preferred embodiment of the recycling method of the blanket (100) comprising hard rubber (101), adhesive layer (102), soft rubber (103), and bottom layer (104) is described for better understanding of the subject and without having any limiting affect.

The invention particularly relates to the method of recycling and reuse of the blanket (100), which is used in printing sector, and which performs the task of taking the ink found on the printing block in a quick and correct way and transferring this ink to the printing material. The blankets (100) on which the invention is applied can have various numbers of layers as shown in figure - 4. In the detailed description, blanket (100) preferably having three layers (101 , 103, 104) and preferably comprising adhesive layer (102) among the said layers is used. The main covering material used in the blankets (100) used in offset printing are generally different with regards to the ink to be used in printing.

The most commonly used blankets (100) are the ones produced from nitrile based rubber (NBR) which are suitable with oil based ink. At the same time, blankets (100) made of EPDM based rubbers are suitable for inks drying with UV beam. And sometimes, mix blanket is used in order to provide use of two ink types at the same time separately. The said mix blanket is made of rubber comprising EPDM and NBR mixture. The hard rubber layer (101 ) found at the upper surface of the blanket (100) is made of EPDM, nitrile (NBR) or mixture of these two (EPDM+NBR) according to its area of usage, and it consists of flux oil, carbon or silica fume, natural rubber, and sulphur.

The recycling method of the blanket (100), which is the subject of the invention; comprises some operations made on the uppermost hard rubber layer (101 ) among the layers forming the blanket (100). Different operation steps are applied for three different situations occurring in the blankets (100) used in the prior art. For example, the operation steps applied on recycling of the lightly damaged or lightly deformed blankets (100) and much more heavily damaged blankets (100) are different from each other.

In general, when it is not possible to use the blankets (100) in the printing machines, the blankets (100) may be in one of three different conditions. These are; lightly damaged, locally damaged, and completely damaged.

Lightly damaged blankets (100) are the blankets (100), slickness of which can be ensured by performing grinding operation up to 1 ,75 millimetres of the hard rubber layer (101 ) and then brought into use again.

Locally damaged blankets (100) are the blankets (100), which have damage or collapse deeper than 0,2 millimetres on the upper layer (101 ) of the blanket (100) normally having 1 ,95 millimetres of thickness. Recycling of these types of blankets (100) can not be obtained only by grinding as lightly damaged blankets (100).

Completely damaged blankets (100) are the blankets (100), recycling of which can not be accomplished by the process steps applied on locally damaged or lightly damaged blankets (100), and which have damages or collapses deeper than 0,2 millimetres on many places of the hard rubber layer (101).

The basic process steps of the method, which is the subject of the invention, applied on lightly damaged blankets (100) are as follows (figure - 1); - Grinding (10) of the hard rubber layer (101) found at the upper surface of the blanket (100),

- Measurement (11) of the surface slickness of the hard rubber layer (101) found at the upper surface of the blanket (100)

• If adequate slickness could not be obtained, repetition of the grinding operation (10),

- Sanding (12) of the hard rubber layer (101) found on the blanket (100),

- Measurement (13) of the surface sensitivity of the hard rubber layer (101 ) found at the upper surface of the blanket (100),

• If adequate surface sensitivity could not be obtained, repetition of the sanding operation (12),

- Separation of the blanket (14) in order to be used in printing machines.

The grinding operation said in the above grinding operation step (10) can be accomplished in various grinding machines such as smooth surface grinding machine, cylindrical grinding machine etc. In the above said grinding operation step (10), surface cleaning of the blanket (100) having normal thickness of 1 ,95 millimetres can be made by grinding up to 1 ,75 millimetres. If smooth surface can not be obtained yet, more grinding operation (10) is not made. In this case, the blanket (100) is considered to be in completely damaged class and complete surface covering is required. The basic process steps of the method, which is the subject of the invention, applied on locally damaged blankets (100) are as follows (figure - 2);

- Determination of the regions with local damage (20), - Placement of rubber in the form of patch made of the same material (21 ) on the determined locally damaged regions,

- Vulcanization (22) of the blanket (100) on which patch is placed, preferably by being vulcanized for about 180 minutes in vulcanization oven at about 6 bar pressure and about 143 °C temperature,

- Mellowing (23) of the blanket (100) following completion of vulcanization operation (22),

- Grinding (10) of the hard rubber layer (101 ) found at the upper surface of the blanket (100),

- Measurement (1 1 ) of the surface slickness of the hard rubber layer (101 ) found at the upper surface of the blanket (100)

• If adequate slickness could not be obtained, repetition of the grinding operation (10),

- Sanding (12) of the hard rubber layer ( 01 ) found on the blanket ( 00), - Measurement (13) of the surface sensitivity of the hard rubber layer (101 ) found at the upper surface of the blanket (100),

• If adequate surface sensitivity could not be obtained, repetition of the sanding operation (12),

- Separation of the blanket (14) in order to be used in printing machines. In the above said grinding operation (10) step of the locally damaged blankets (100), on which patch is placed, the thickness of the hard rubber surface (101 ) serves as basis. Grinding operation (10) can be made up to 1 ,70 millimetres thickness of the blanket (100). The actual operation to be made on the blanket (100); is to obtain blanket (100) having appropriate thickness for being used in printing without unveiling the bottom layer (104) or the soft rubber layer. Thickness and size deflections due to usage are determined in some blankets (100) as a result of recycling operation. However, these size deflections do not reach a level which would affect the printing quality.

The patch, which is placed on the determined locally damaged regions in the operation step of placement of rubber in the form of patch and made of the same material, can be placed with or without glue. Vulcanization operation (22) can be made in the both said situations.

The basic process steps of the method, which is the subject of the invention, applied on completely damaged blankets (100) are as follows (figure - 3); - Complete scraping (30) of the hard rubber layer (101 ) found at the upper part of the blanket (100),

- Making surface covering (31 ) on the scraped upper layer (101 ) of the blanket (100) by hard rubber paste preferably in 2 to 3 millimetres thickness,

- Vulcanization (32) of the blanket (100) on which surface covering is made, preferably by being vulcanized for about 180 minutes in vulcanization oven at about 6 bar pressure and about 143 °C temperature,

- Mellowing (23) of the blanket (100) preferably for 24 hours, following completion of vulcanization operation,

- Grinding (10) of the hard rubber layer (101 ) found at the upper surface of the blanket (100),

- Measurement (1 1 ) of the surface slickness of the hard rubber layer (101 ) found at the upper surface of the blanket (100)

· If adequate slickness could not be obtained, repetition of the grinding operation (10),

- Sanding (12) of the hard rubber layer (101 ) found on the blanket (100),

- Measurement (13) of the surface sensitivity of the hard rubber layer (101 ) found at the upper surface of the blanket (100),

· If adequate surface sensitivity could not be obtained, repetition of the sanding operation (12),

- Separation of the blanket (14) in order to be used in printing machines.

In the above detailed description vulcanization operation (22, 32) is applied preferably by vulcanizing for about 180 minutes in a vulcanization oven at about 6 bar pressure and about 143 °C temperature. Similarly, vulcanization operation (22, 32) can be made in hot press machines or boilers with or without pressure.

Vulcanization operation (22, 32) is made in press or boiler system machines which are vulcanized by; - System heated by vapour

- System heated from below by natural gas, bottled gas etc. components,

- System heated by circulation of oil, and

- System heated by electricity.

In the above said, complete scraping (30) operation of the hard rubber surface (101 ) of the blanket (100), scraping of the hard rubber surface (101 ) can be accomplished preferably by performing grinding in grinding machines.

Hardness level of the recycled blanket (100) is measured with shore A type in order to check whether it meets the hardness criteria or not, which is required for being used in printing. If the result of measurement is negative, the blanket (100) is put into process as completely damaged.