Let's see how the films prepared in printing are transferred onto the paper by means of plates.
Printing Techniques
The process of the dot, which is done with the help of humidification and ink, is called offset printing. The grains formed on the mold surface by the dots on the film surface, which we call tram, are filled with inks carried by the rollers. The filled dots transfer the ink onto the rubber, which we call blanket, on another boiler, and onto the paper.
● Offset printing
● Letterpress Printing
● Graffiti Print
● Flexo Printing
● Screen Printing
● Digital Printing
Angles in Color Points
As the dots print on each other at an angle and the ink has a transparent (non-covering) feature, various colors are formed. In order to obtain a good print, a particularly good film, a quality ink series, and precise machine settings are required for a healthy transfer job. Some types of fast and healthy printing in printing processes and terms used.
● Printing method on the spread
● Normal Revolta printing method
● Skirt - Scissors Revolta printing Method
● Front - Back print
● Scissors - Scissors revolta
● Skirt - Scissors revolta
Sheet Offset
The mold sensitized with a special emulsion is exposed with light and the black areas on the film are left without light on the mold. Other transparent areas are cooked by being saturated with light. Then, the non-light surfaces on this mold pour their enamel during the bath, creating an emission that will accept paint.
As the resulting emission does not hold water, it holds the paint coming from the rollers and transfers it to the rubber. Blanket, on the other hand, gives it to the paper as it takes the paint on it. Thus, the dots on the film are transferred to the paper exactly according to the color of the ink. Today, offset printing is done on 4 main colors. This is what we call trichrome printing in printing.
Form Printing Method
It is a technique used in multi-page works such as Book-Catalogue etc. Its purpose is to allow the pages to follow each other when the paper is folded and to reduce the collation process. In addition, it ensures that complementary and continuation pictures that may be on the corresponding pages continue in the same color tone.
Water Path of Paper
Water path of the paper means the direction (texture direction) in which the pulp flows from the hopper to the sieve continuously during manufacture. Because cellulose fibers stretch in this direction and become felted. The most practical process to find the water direction of the paper is as follows: A piece of paper is folded horizontally and longitudinally. The folded places are slightly moistened and scratched with a nail. After this process, the waving side of the paper shows that the water direction is opposite. Because the cellulose fibers are broken in this direction and cause fluctuations in the paper. The other side that does not fluctuate shows the side where the water direction of the paper is. The waterway of the paper is extremely important in printing and binding.
Normal Revolta Printing Method
It is the technique of printing the front and back of the paper in formats suitable for the machine size by printing 4 colors with 4 molds. It saves both the number of patterns to be printed and the time to be lost in machine settings.
The movement of the paper in the machine is in the form of the apparatus we call scissors, holding the wide side of the paper and carrying it to other printing units. We call the part of the paper held by the scissors "Scissors".
We also call it "pose", which sets the paper just before it is picked up by the scissors to ensure that the prints on the paper can be printed in the same place. It is the type of printing made without changing the scissors of the paper in normal revolution printing. It is the process of printing the front and back of the paper with the same pose and the same scissors.
Skirt-Scissors Revolta Printing Method
The place where the scissors hold is scissors, the place where the pose apparatus pulls is the pose. What are the remaining two edges of the paper called? The side behind the point held by the scissors is called "Skirt" and the side opposite the point pulled by the scissors is called "Counter Pose".
The purpose of this printing technique is still the same. Color printing is done on the front and back of the 4 plates at once. In other words, the aim and the results obtained are the same as the revolta technique. The difference is only in the method. This time, the paper is tumbled and printed as skirt-scissors. The pose is still fixed. On the other hand, the counter pose is an apparatus used for printing the front and back printed materials in the same setting, mostly in front+rear prints.
By Printing Systems of Papers Properties
Web Offset (Rotation) Printing Technique
In 1912 Casper Herman (Vomag) started to manufacture the first rotary machines. It is an advanced form of offset printing system. This system is used for print works with a large circulation in today's world. Today, the advantages it provides for circulation works in the printing field are many.
● Tram: Points that create transitions (tones). (Number of dots per 1 cm)
● The biggest feature of web offset (rotation printing) is that it can print on paper that is wrapped in COIL.
● As a printing system, web offset machines are not much different from flat offset machines that print in sheets, except for the way they use the paper (sheet/roll).
● The biggest feature of web offset is that it is both technical and commercial. However, some rotation experts believe that sheet offset gives better results. The paper, on which the dye is transferred, passes through 110-140 degrees and is shocked by a temperature that suddenly drops to +13 degrees, and finally, the paper gains brightness as a result of the sudden drying of the paint. Before coming to the folding hopper, paper emission from the silicon chamber passes through the silicon. Therefore, the glow gains + value at this point.
● Since these machines do certain works and are manufactured for these works, they are added to the equipment according to the necessity and nature of the work. (For example; devices such as folding, cutting, blending, packaging, drying etc. are added)
● In the web system, each unit consists of two molds and two rubber pots. The printing happens from rubber to rubber. The paper in the form of a coil passes between two rubbers and prints one rubber top and the other rubber bottom. Thus, both sides of the paper are printed.
● The most important feature of web offset inks is drying. This means that heat-setting ink should be used. For this, ovens or tunnels should be used to ensure drying between the final printing and folding.
Some technical features of web offset (rotation) machines
Remote control of the machine and print settings can be made with the central control system in these machines, valid for each unit. We see 2 types of systems in the rotation printing technique. Coldset (Non-Drying) and Heatset (Drying). We've talked about the Heatset edition so far. Coldset printing, on the other hand, cannot be printed on machines that do not have a drying tunnel that prints on uncoated papers (such as Newspapers), such as 3rd or 1st Pulp.
● Central control system
● One or more printing units
● Coil stand
● Paper tension
● Dryer
● Cooler
● Fold
●
● Collation
● Desired number of jobs
Screen Printing Technique
It spread from Japan to America and then to Europe. It is especially used in advertising prints. As it is known, in offset printing technique, printing was done directly only on paper and paper type sheets or coils. In screen printing, not only paper, but also cardboard-cardboard-pvc (hard and soft)-many plastics (synthetic) materials, metals, glass-ceramic-textiles, etc. It is possible to print on materials such as The success in this printing technique is in the workshops that know the technique well (ink is very important in this printing technique) and use researched ink suitable for quality work. In this printing technique, silk screens are used instead of molds. This is a kind of tulle called pure silk, nylon perlon and metal fabric. Because this tulle is perforated like a sieve, it is called sieve printing. Paint thickness is 6-10 times more than letterpress printing. Screen printing is done in 2 parts.
Silkscreen Printing
For centuries, fabrics have been printed with stencils in China and Japan and sold to many countries around the world. At first it was not possible to print figures with templates such as paper and leather without leaving traces of connection. The stencil traces remained on these surfaces at certain intervals. Over time, figures excavated from paper were pasted on these templates, which were used in the past in the Far East, and the result of printing was obtained without leaving any traces of connection. A carrier and paint-permeable porous surface mounted on the frame is required so that the prints can be made without traces of attachment. We call it GAZE or SIEVE CLOTH in screen printing.
The paint is passed onto the fabric with a tool we call a squeegee (the object that is moved back and forth on the sieve so that the hard rectangular smooth paint held by the master is passed through the sieve). This dye passes to the fabric only from the parts of the gaze (screen cloth) that are not covered. Since the thin gauze threads do not prevent the dye from passing through, the dye is spread cleanly and smoothly on the surface of the printed material. Printing done in this way is also called Film Printing or Template Printing in textiles.
As this printing method is rich in application variety, it is applied from the simplest hand workshops to the largest factories.
Recently, screen printing has become competitive with roll printing. Screen printing is more convenient for small-run printing, as it can easily and quickly change printing shapes, in a simpler and cheaper way. The dexterity of the master who does this work is very important.
Silk gazes are tissues made with the rotating needle technique that does not slide in any direction. Later, special gazes were made from natural silk for stencil printing.
Silk gazelles lost their importance after the emergence of synthetic fiber. (This is because synthetic fiber was preferred due to its high chemical resistance, flexibility and durability). The most suitable fiber for gauze is polyamide.
Template Preparation
First, you need a wooden or metal frame, a synthetic or metal silk squeegee to be able to print. Silk is stretched to the frame and poured into a film on enameled silk. (It can be a fastener, stapler, sticking). The places that see the light with the bathroom are cleaned. Then the template is washed with pressurized water. Exposure time is determined in a few tries according to the distance between the light and the template and the power of the lamp.
Printing
Manually: The paper, fabric, plastic, leather, etc. to be printed is placed on a flat surface. The template is placed on the material to be printed. Some paint is poured into the inside of the stencil and drawn once or twice on the pattern with a squeegee. This pulling is the skill of the master who does this work, and the movement and power in the manual pressure must be equal. These prints are then placed on individual racks to dry.
With the machine: This is very simple. The template is connected to the machine. Printed directly.
Important Information in Screen Printing
When printing on plastic printed materials such as acrylic plystrol, properties such as good adhesion, quick drying and high light resistance are sought in paints. For example; If small table top flags and pennants are to be made on cloth, special fabric dyes. If printing will be made on materials such as polyester or polyethylene, special polyethylene inks and high-density paints specially prepared should be used if very bright and durable printing is desired on surfaces such as glass and metal.
Screen printing inks must be stored as a set. Otherwise, it will harden after 8-10 hours and cannot be used again.