Stencil printing its advantages and disadvantages

 Stencil printing method

This is also, one of the oldest methods of printing but it is not used to any great extent. Really speaking it is not a printing process at all as the color is applied to the fabric not by impression as in block or roller printing but by brushing or spraying the interstices of a pattern cut out from a flat sheet of rental or waterproof paper or plastic sheet or laminated sheet.

A stencil is prepared by cutting out a design tram a fiat sheet of cartridge paper, metal, or plastic, with a sharp-pointed knife.

Stencil printing

Stencils made from a thin sheet of metal are costly and less easy to cut with accuracy and more difficult to handle than those made from cartridge paper.

Metal stencils are durable but are liable to damage during working because of their thinness.

It is not possible to cut a perfect circle or a ring or any other complete outline on a stencil plate which if cut, would fall

out of the pattern at once leaving a spot. To prevent this, some form of a tie' is used to link such shapes to the main stencil.

The outlines of a pattern are, therefore, broken at convenient points by cutting the stencil partially; the uncut portions serve as 'ties' to support the inside parts.

Sometimes hair is used to hold to the main. Design those parts or areas that would otherwise fall out.

The ties strengthen the stencil and form an essential feature of the design. Procedure: In actual practice, the stencil is laid perfectly flat on the fabric to be printed and the color paste is then brushed through its perforations with a brush.

The plate is then lifted when the pattern appears on cloth as a colored silhouette corresponding with the cutout! Parts of the stencil.

In patterns with two or more colors. A separate stencil is required for each color as in block printing.

The cloth is stencil printed throughout in one color first and then the other colors are printed. Every repeat can be colored differently desired.

The color can be brushed, dabbed. Sponged, or sprayed by means of a spray gun through the stencil lo.obtain different elects.

Further, different colors can be applied to different Paris of the stencil and then blended together with a sweep of the brush before the stencil is removed.

Such effects are obtained by block or machine printing. The method is mainly confined to the printing of wall hangings, decorative panels, curtains, bedspreads, table cover3, cushion covers, etc.

Any kind of color can he used a lot the paten in this method. Oil colure is often used for heavy, woolen goods, velvets, jute cloth, buckram, etc.

 Ever. Water Colors that can be used for lighter goods is fast! colors are not required.

Advantages of Stencil Printing:

1. the method is simple to operate and does not require elaborate or expensive equipment; the cost of production is low.

2. The stencil plates can be cut rapidly and can be used with prolix in executing small orders for which the expense of block cutting would be prohibitive.

3. A great variety of graded color effects can be obtained from one stencil by blending different colors or different parts oil the stencil with one stroke of the brush; suction effects cannot be obtained by other methods

4. Any kind of color can be used in stencil printing including oil colors and watercolors, other methods of printing do not permit the use of such colors,

Disadvantages of Stencil Printing

1. Complete rings or circles, as well as unbroken lines, cannot be obtained by this method; the designer's freedom is, therefore, limited;

2.  The process involves manual work and is, therefore laborious

3. The method is not suitable for large-scale production. 

Prepare design on trace paper for printing

The method of screen preparation in screen printing:

The most popular method of making the lawn is photographic method. In this method, the finer fabric of silk, isolation or polyester is used. First of all, the fabric is made on a wooden or metal frame. 

The fabric which is extracted in the frame, is cut, and sticks the fabric out of the edges with the help of tape on the frame.
After this, they paint the whole frame with Lacquer, which makes it waterproof. After this the frame is well-mixed with hot water.

If there is any tension in the clothes of the screen by washing with hot water then the body is finished. After that dry the screen.  After drying down on the screen. Casting from any solution passed.

Designing on trace paper

 Every one color in printing has to make a separate design screen. As if there is a full-leaf design, a screen will need a separate screen to print the full color red and to print the leaves green.

 To make this design on the screen, it is necessary to first design a trace paper. 

Here, it has to be kept in mind that the design made on trace paper is made of blackleg, so that the light can not be passed through it. This design made on trace paper is called Positive.

Thickeners

Thickeners

 When we dye the cloth then dissolve the color in the water and run the fabric and simultaneously add the chemical as per the requirement. But if we have to chill, then the use of Hem coloration can not be used in printing because if we print that solution, then wherever this slurry is used it will spread on the fabric. So we will not get Sharp design. To remove this shortage, chicken like starch, sodium alginate etc. are mixed in color solution. This makes the solution very thick, so that the color does not spread on the cloth.




The choice of the right Thickeners depends on the things given below. 
1. Stability of printing solution (Print - paste stability)
2. Property of dried thickener film
3. Effect on color yield
4. Time to process the process of turning the thinner into paste and remove it from the cloth
5. The Cost of Thickener

Stability of printing solution:

Thinar should be such that when combined with color and chemistry, it remains stable. If Cationic Dyed is mixed with Anionic Thickener, then by meeting both, it creates a substance that is insoluble. This changes the viscosity of the solution. Similarly, anaeric thinners should not be used with metals like salts such as aluminum sulphate.

Similarly, pH of solution should also be kept in mind that some thinners such as sodium alginate, more acid or alkaline pi. H. Creates a kind of gel-like material in
The biological process also has a bad effect on natural thermometers because enzymes are formed by this process which break the chain of these polymers. Therefore these substances have to put substances that stop the biological process from it.

 Properties of The Thickeners

When the cloth is cleansed after filtering with thinner paste, the film of Thickeners is made up of clothes. There is also a color in this film. If the film does not get well with the cloth then the printed texture passes through different mechanical processes, then the film breaks, which also makes the paint present in Phil also useless. Therefore, the film of Thickeners should stick on the cloth.

Effects on the color of the Thickeners:

It has been observed that the steaming process is the best color correction. Steam | The procedure works in the steps given below.
1. Steam Thinner's film is condense, so that the film is full of flowers. Goes swell.
2. This swared film which also has color, makes small dye baths on the surface of the fibers.
3. In the next stage, the color goes into the film from the small Dye bath.
It has been observed that the thickness of the low solid content fixes more fiber than the thicker than the higher solid content. The reason for this is that thinner ratio with low solid content creates thin films on the scale, which makes it less time for the colors to move from film to clothes or fibers.
The time it takes to process the thinner in paste and remove it from the cloth

The time required to change the thinner's paste and remove it from the cloth: When selecting thinner, it is very necessary to see that the thinner is in the form of a paste. How long does it take to change, and how much time does the clothes go out after printing?

Thickeners price:

While selecting Thickeners it is also necessary to see that the cost of Thickeners is reduced and there is all the qualities as per the requirement.

Pigment printing

Pigment printing

 In pigment printing, pigments that are not soluble and which do not have any action with fibers, on the top of the cloth, with the help of gum, the kind of design that is needed, the beds are given. Its emulsion before printing on the cloth (emulsion). In this emulsion, mix many types of chemicals and make the solution for the pie. They make two types of emulsions for printing.

1 Oil - In-Water Emulsion
2 Water - In Oil Emulsion

 The pigment printing has the importance of the substances given below

1. Pigment Deduction
2. Winder
3. Thicker and need chemicals to thicken paste.

Good pigment printing will be those qualities given below

1. Bright and good color value
2. Being soft in printed clothes
3. Good color fastness 

Pigments used in printing are made of synthetic organic materials. Some pigments such as carbon black, titanium dioxide, copper and alluminium alloys and iron oxide are natural See you at the stage.

Printing in pigment is pure in three stages.
1. Printing
2. Drying clothes
3. Curing

 Pigment printing does not require water at any stage. Pigment printing is mainly used in cellulose ether, sodium alijenet etc. Pigment printing can be used in the recipe recipe.
She gave down
 Pigment     x
 Reduction thickner   1000  -5x / 2
Winder 3x / 2

Use one of the ingredients given below to print a single pigment emulsion of tepidity. This oil-in-water (water-n-water) is suspended.


1. Ekron Pigment Emulsion
2. Akon Bidders
3. Pidifiera as per the need to forget
4. Acid dropping catalysts like dye. Ammonium hydrogen phosphate

5. Kerosene
6. Water
 Acron pigment emulsion
In this emulsion, very fine inorganic pigment occurs in the 

dispersal phase.  In this, the emulsifier is also mixed.

Akron Binders - It works in Binders Roller Rotary and Flatbed Printing.
Pidifix Fixer:
In the printing of artificial fibers or their blades, the fixer (1 - 3%) should be used.

Acid dropping catalyst
    diammonium phosphate is the best catalyst

 Kerosene
Use kerosene to make printing solution.

Water
Water is used to make a printing solution. Preparation of Reduction Binder

Preparation of Reduction Binder:
 Aaron Binder-  10 Parts
 Water            -   9 parts
Kerosene    -      81 parts
 Total          - 100 parts

 Preparation of Solution for Printing:

 Reduction binder              - 95 parts
 Aaron Pagment Emulsion-1 Part
 Ketlist                             - 4 Parts
 Total                              - 100 parts

After printing with the solution given above, do the curing for clothes for 4 minutes at 150 degree centigrade.

Advantages of Pigment Printing:

1) It can be used in all types of fibers. 
2) This printing is cheap, attracted and less time consuming.
3). No need to wash clothes after printing.
4) These colors are fixed.
5) Pigments can also use other colors

Fixation of printing

Fixation of printing

All textile material is require dye fixing after dye and printing printing fixation following type there are given below

Type of printing fixation

1. Steam Fixation

2. Dry Heat Fixation

3. Wet Fixation

4. High Temperature and High Pressure

 Steam Fixation

This method is suitable for all class of dyestuffs. In the steamer, fibre and thickener absorb a certain amount of moisture. As a result, swelling of the fibre and of the film of thickener takes place. 

The dyes and chemicals incorporated in the printing paste pass into the solution and thus enter into the reaction. During this phase, the dye commences to penetrate the swollen fibre. Depending upon the class of dyestuff and the kind of fibre, chemical or physical combination of the dyestuff takes place with the fibre molecule. 

In order to accelerate the process of fibre swelling and dyestuff penetration. The printing paste may contain swelling agents, such as urea, thiourea, glycols, carriers, etc. In case of synthetic fibres, the fibre swelling takes place only under high pressure or high temperature steaming. 

Vat, indigosol, azoic, reactive and aniline black can be fixed by normal steaming. Disperse dyes on synthetic fibres are fixed under high pressure or high temperature stemming.

Dry Heat Fixation

 Usually pigment, reactive and disperse ayes are fixed by this process Baking chember or hot-air stenter having high temperature tones is use for this purpose. Fixation takes place 130°-150°C within 5 to 3 minutes pigments, 150 C for 5 minutes for reactive: and 180°-200 C for  to 30 seconds for disperse dyes

 Wet Fixation

The methods of wet fixation for the different types of dyes are : Nitrite process for indigosols: oxidation of vat dyes, aniline black and metal complex formation in phthalogen blue, alkali fixation of reactive dyes and two-phase printing of vat dyes and reactive dyes

 High Temperature and High Pressure 

Steaming In a print house, the steaming operation required to fixation dye on the fabric has been often a bottleneck and also it is a relatively expensive process as far as steam consumption is concerned. In order to overcome this problem two processes viz.,
 high temperature steaming (Flash aging) and high pressure steaming process and mchines have been developed. In the case of synthetic fibres, disperse dyes do not fix spite of long steaming at 100-102°C 

in pressure steaming they can be fixed within 20 to 30 minutes at .5 to 2 atmosphere pressure similarly. in high temperature steaming these colours are fixed at 180°-200°C in 30 to 50 seconds only. 
Pressure steaming is a discontinuous process and is not suitable for high rates of production. 
High temperature steaming fixes reactive dyes on cotton and reactive/disperse or metal complex dyes on synthetic fibres in 30 to 60 seconds only. Reactive dyes fixed by high temperature steaming give better yields than thermofixation process.

Style of printing

Style of printing

The 'style of printing refers to the method used for producing a given design on the fabric. The three main styles of printing are given below

 Direct Printing 

In this style the color is applied directly to the cloth by printing and is fixed by steaming or baking. This style of printing can be divided into the following three sub-groups

       (a) white and dyed ground.

       (b) semi-blotch, and

       (c ) blotch.

Following class of dyes are applied commonly in direct style of printing: Vats, indigosols, azoics (rapidogen), pigments, reactive and aniline Black 

Discharge Printing

In this style, a dyed ground is removed locally leaving a white or coloured pattern on the original ground.


Vat dyes are used as illuminating colored effects and Rongalite and alkali along with suitable chemicals act as discharging component for both white and colored discharge. Following ground shades are commonly empleyed for getting white and coloured discharges: Direct, azoic, reactive, indigosol derived from indigoid vat dyes

 Resist Printing

The object of this style is to produce a pattern on a culoured ground by first printing on the white cloth a substance that will prevent the fixation of any colouring matter applied over it

In resist styles of printing, vat, rapidogen, pigment, and reactive dyes can be used as illuminating colours while a number of chemicals as resisting agent. Increasing printing effects can be produced by using the following

Metal Printing:  

  Metallic powders are applied to produce designs in gold, silver, etc. They are printed with synthetic binders such as Binder SL.N

Crimp Printing:

This printing is carried out to give crimp effect to the fabric at the printed places .Caustic Soda up to 50 % strength is incorporated in British gum paste and is printed on' the cloth. The whole process depends upon the tensionless drying of the printed cloth and slack washing in batches

.

Khadi Printing : 

 Production of matt white and matt coloured effects can be brought about by titanium dioxide. Pigment powder, etc. The deeper the dye, the better is the print.

Flock Printing:

In this style, velvet type of designs are produced on plain cloth by fixing silk or man-made fiber flock with an adhesive during the printing operation

Rotary Screen Printing

Rotary Screen Printing

In this type of printing, the screen is wrapped on a metal cylinder. The solution of the color is inserted from one end of the cylinder. This roller rotates by mechanical method. When the cloth is to be printed then this cylinder will sit on the cloth Goes and starts to rotate, so that the entire screen on the fabric (which is wrapped on the cylinder) is printed. In this printing, the color of the screen is the same as the screen is needed. The cylinders are wrapped on this process by about 100 meters /

 Part of the rotary printing machine

Some of the most important devices fixed on the rotary screen printing machine is as follow

(A) Feed Device: This consists of guide rollers with or without scary and a pair of clothing guider  it is meant to feed fabric

(b) Vacuum Cleaner: Vacuum cleaner removes any loose lint or fluff from the surface of the fabric

(c) Gluing Device: This device consists of an expander roller and a pressing

(d) Printing Bed: Printing is carried out by circular nickel perforated standard size of the screen (Mostly 640 mm circumference) which are mounted on the sized screen ( flatbed of the blanket which is an endless washable darex type.

(e) Feeding Pumps: Colored feeding is carried out into the screen, by non- reversible type pumps made of stainless steel.

(F) Drier: Printed fabric is fed by means of a systematic conveyer belt to the hot air drier which consists of a high-grade beat insulated hot air chamber equipped with a powerful radial fan and exhaust fan. Drier has a plaiter at the delivery end.

(G) Squeeze System: The important part of the machine is a squeeze system that feeds the color of the fabric. There are mainly two systems:

(i) pneumatic  squeeze system working with a doctor blade

(ii) Magnetic rod system working in the influence of the magnetic field’. Modified squeeze consists of plastic tip rubber blades. Different sizes of squeezes are used for various types of prints such as cutlines, blotches, etc.

Advantages of Rotary Screen Printing:

Production of printed material by this method is the highest ás compared to roller printing or automatic flatbed printing method;

 As many as 24 colors can be printed by this method but 8 to 10 colors can te printed easily, Joint marks which am perceptible in flat-bed and hand screen printing methods are totally absent In rotary printing.

Hall tone effects and vertical! lines can be produced very successfully by this method; The prints produced are froe from the smudging effect which is quite severe in roller printing.

Disadvantages of Rotary Screen Printing :

The method is not economical for short runs of the fabric due to the high cost of engraving of the screens; The size of repeat o! the design is limited to about 55 cm. which is less than that of a hand screen.

Screen Printing

Screen Printing and Defects and Their Remedies

When you put a paste of Color, then the color comes through the fine holes of the design and comes on the fabric. In this printing, a color can be printed from one screen in the same way as the color printing. For every color design, 

There are many runs needed in this.
 In manual screen printing, the fabric is piled well on the printing panel and it is taken care that there is no fall on the cloth. 

Therefore, by pulling this cloth properly, fix it with the help of pins and Put the screen on the cloth and put a color paste. Spread the paste on top of the screen with the help of Squeegee, which spreads well on the screen, so that the color can be seen from the hood of the screen. Check it out.

making a screen for printing

Screen printing is a form of stencil printing. This printing has a frame for printing which is covered with silk, metal, nylon, or polyester cloth. The screen is prepared like this. On the screen, a photographic film is coated with a design based on trace paper. Design made on the screen is made of very fine holes. 

Machine screen printing

This kind of printing can also be done by machine, which is called flat band printing. Textile with such a machine is constantly printing. With the help of a cloth conveyor belt, the printing keeps on moving forward. In the law, the screen is one after the other, which is above the belt. 

The time of printing stops the belt so that the cloth comes in a steady-state, the screen comes on top of the screen and after printing, the screen is up like the above and the cloth moves further. The next screen is placed on another screen. This process keeps running on the fabric (which is printed from the first screen). 

In this method, the colors are brought to the screen with the help of Pump and the skiing process comes from mechanical squeezing.
Two types of suites are used. A conventional squeegee moves forward and backward on the screen with the help of a motor, and there is a squire like the other roller bar which keeps roll on the screen.

Printing in flatbed 6 Maybe at a meter/minute speed. Fig - The flat-screen printing process is shown in

Vertical Duplex Screen Printing Machine
 

This new vertical duplex screen printing machine has been developed by the firm Franz Zimmer. The screens are used vertically at twin pairs, which clamp together over the cloth at the moment of printing. They register the prints exactly at the same place on the back and face of the cloth. 

This is insured by the method of packing the screen. The machine provides a new technique for the whole range of textiles, particularly very wide and thick materials such as drills, blankets, toweling, etc. It is possible to print on both sides with ease and economy. 

Depending upon the type of dye used, the fabric after printing and dyeing is passed through either a steamer or a polymerize to fix the dye the fabric. The fabric is then washed on a soaper and dried. The details regarding steamer, polymerizer and 

soaper are mentioned earlier in the Chapter n Machinery Used in Dyeing.

Screen Printing Defects and Their Remedies

The defects that occur in screen printing is not as many as those which occur in roller printing because being a hand.

printing process, the defects which arise in a machine due to say,. doctor blade roller engraving, are absent in screen printing. Other defects and the remedies thereof are as under  

Uneven Prints :

These occur if the printing table is not level or if the edge of the rubber squeegee is uneven. The remedy lies in using a perfectly lovely table and sharpening the edge of the squeegee.

The badly bleached cloth also gives rise to uneven prints due to uneven absorption of color; the remedy is to use a well-bleached cloth.

Lighter Prints

These arise il the openings of the screen get clogged particularly by pigment colors which dry up too soon; the remedy lies in washing the screen immediately after use because it is difficult to dean the opening once the synthetic resin ( binder ) is set

Lighter prints are also caused it the colour paste is too thick; the paste produces a weak impression because it is too solid to be absorbed freely. The remedy is to thin down the pasta, The foam produced in the paste also causes Lighter prints; the remedy lies in adding anti-foaming agents like pine oil, turpentine or cyclohexane to the paste.

Specks of Dark Color:

These appear as minute specks on the cloth due to faulty color mixing; the remedy is to mix the ingredients properly.

Small specks on the unprinted portions of the cloth appear due to Pinholes on the screen or due to negligence of the screen maker. The remedy is to check the pinholes and cover them with lacquer.

Light and Dark Prints:

These appear on the selvages steaming in the Star Ager is not uniform; uneven prints. appear one to batch-wise steaming on batch rollers. The remedy applies pressure on the squeegee evenly ensure proper steaming and avoid too much loading on the roller

Once the cloth is badly printed, it is difficult to rectify the defect; therefore, great care has to be taken to prevent the faults and to rectify the same immediately so that The number of rejects is kept to the minimum. 

 

Advantages of Screen Printing:

1. The method is simple to operate and does oat require elaborate and expansive equipment.

2. The method enables new patterns to be produced quickly and without a large initial expense since the screens can be produced cheaply.

3. The method is useful for printing knitted rayon fabrics which cannot be manipulated satisfactorily on the roller printing machine.

5. The method is economical in production and manually less exacting than block printing.

6. Blotch designs can be printed by this method which cannot be printed by block or roller printing: further, it is possible to produce larger repeats than those in roller printing.

7.  As many as 16 colors can be printed in one pattern by this method. In roller printing, even though it is possible to do this, it is difficult in practice to use more than 6 rollers.

8.  Prints obtained by this method are more intense, more bright and possess natural bloom as corn pared with those obtained by roller printing method; further, by using fine- mesh screens, sharp line effects including vertical lines can be produced by this method which is difficult it to produce with roller printing.

 

Disadvantages of Screen Printing

1.  For high production, a large number of tables have to be used requiring huge space with incidental overheads; in roller printing, tale space required Is very much less.

2. Delicate shading and gradation of colour are difficult to obtain by this method and the joint marks at the repeals are often perceptible.

3. Fine mesh screens used for sharp line effect: often get choked rendering the screen redundant. 

Printing and type of printing

printing

The color on the clothes means that the color at the selected point of color

 Is selected i.e. all colors in colors of colors

Put the color of clothes that touch the place in the printing

 Let's print. One way by which we wear clothes

 Make well and according to the mind, clothes

But any size can be made in the printing

 Color should be prepared for It is very focused that

To further strengthen this color, thickness in this way

It is inserted that the use of starch, gum etc. to wear

The advantage of colors prevents the spread of colors, not painted colors

 Exit the picture and get sharp design

is. Different methods are used in printing, which

 It is as follows.

Types of printing

1 block printing

2 screen printing

3 flat bed printing

4 Roller printing

5 Rotary printing

6 Transfer printing

7 Flock printing

Each method has its own use. Block printing

The oldest and most simple method of printing. This printing hand

Made of shapes on wooden blocks. Of this method

The capacity is very low but very low if you have the same amount

To do so it is very cheap

Digital printing is being used a lot nowadays

Machine use is not present in screen printing. First

Screen is drawn in which the design is small (small holes)

Make this screen on clothes and color it

Paint on the screen where the design is made,

Comes through and it is printed in this way.

Flat bed printing is an advanced form of screen printing in which. Printing machine, printed in roller printing .The design is designed by digging on the roller and Roll it in different roller-colored characters for each color. Does a different use cylinder Rotary printing is a mixture of screen and roller, in which the screen. Designed and on screen screw and hollow roller. Is wrapped. Whenever the pressure in the roller is required. So this roller fills in color. So that the color is made in the screen. Comes through the design hole. After printing, fixes the colors on the fabric. This color comes with gates or hot-

Hitting is determined by the steam, after which the clothing is needed. Is washed according to

There is a different style of printing

1 direct style

2 Resist  style

3 Discharge style