Prepared By : Prepared By : Mazadul Hasan sheshir ID: 2010000400008 13thBatch (session 2009-2013) Department : Wet Processing Technology Email: email@example.com Blog : www. Textilelab.blogspot.com (visit) Southeast University Department Of Textile Engineering I/A 251,252 Tejgaon Dhaka Bangladesh ©right
PRINTING The printing is described as localized dyeng, dyes or pigment are applied locally or discontinuously to produce the various designs. Printing is the production of all active designs with well defined boundaries made by the artistic arrangement of a motif is one or more colors. Printing is a process for reproducing text and image, typically with ink on paper using a printing press. It is often carried out as a large- scale industrial process, and is an essential part of publishing and transaction printing. Screen printing is a printing technique that uses a woven mesh to support an ink-blocking stencil. The attached stencil forms open areas of mesh that transfer ink as a sharp-edged image onto a substrate. A roller or squeegee is moved across the screen stencil, forcing or pumping ink past the threads of the woven mesh in the open areas. Screen printing is also a stencil method of print making in which a design is imposed on a screen of silk or other fine mesh, with blank areas coated with an impermeable substance, and ink is forced through the mesh onto the printing surface. It is also known as silk screening or serigraphy.
PRINTING printing 1. used to add color to localized areas only 2. allows for greater design flexibility and relatively inexpensive patterned fabric 3. wet prints use a thick, liquid paste 4. dry prints use a powder 5. foam prints use a colorant dispersed in foam
printing methods digital printing— • ink-jet printing heat-transfer printing • design transferred to fabric from specially printed paper by heat & pressure electrostatic printing • prepared screen covered with powdered dye; passes through electric field & pulled onto material foil printing • adhesive applied to fabric, foil heated on heat transfer press & bonds to adhesive pattern stencil printing • separate pattern cut for each color, color is applied in thick paste or sprayed on with air gun
What type of printing method you know? There are three methods of pattern dyeing and printing: Direct printing Resist printing Discharge printing
What type of printing method you know? Direct Printing: In direct printing a design is etched into a copper roller. A dye that has been thickened into a paste with starch, gelatin, or synthetic polymers is applied to the etched area while the un-etched surface is kept clean. The color design is transferred to the cloth under pressure. Direct printing may also involve forcing the paste onto the fabric through a screen, a technique similar to stencil printing except that the screen controls how much paste is applied to the cloth. Resist Printing: In resist printing a reverse-printing method, a dye repelling substance is selectively applied to the cloth, which is then placed in a dye bath. This method is used for example, to produce white polka dots on a color background. Discharge Printing: In discharge printing, the whole fabric is dyed. A pattern is then printed on the fabric with a chemical that oxidizes or reduces the dye, creating a white pattern on a colored background.
All others of printings are--- Allover print. Screen print. Reactive print. Print with plastisol dye-stuffs. Pigment print Flock print Foil print Lurex print Embossed print Heat transfer print Hi-density print Dip-dye print.
Factors Affecting Cost of Printing 1. Size of printing 2. Number of color of printing 3. Any grading of size of printing from size to size 4. Any restriction/selection of use of dyes and chemicals 5. Lab test requirement 6. Wash sustainability 7. Tolerance in placement of print art-work 8. Tolerance in color shade variation 9. Place of printing 10. Type of printing
Steps of printing:- Preparation of the fabric to be printed. Preparation of the print paste. Making an impression of the print paste on the fabric. Drying of the printed fabric. Steaming of the printed fabric. After treatments (soaping etc)
Printing process:- Sychrop print\ hand print ↓ Dryer (temp 170 – 172) ↓ Quality inspection ↓ Sewing.
Steps of printing section :- Design ↓ Expose ↓ Color ↓ Develop sample
Process of after Production Primary Printing Inspection:- Approval ↓ Strike of Approval ↓ Hand over (Measurement Chart) ↓ Pre-production meting ↓ Quality Report ↓ Total Production Summary.
Roller / Rotary Printing This process involves a print engraved roller, and the fabric is guided between it and a central cylinder. The pressure of the roller and central cylinder forces the print paste into the fabric. Because of the high quality it can achieve, roller printing is the most appealing method of printing designer and fashion apparel fabrics. paste (like a thick paint) that is applied to an Long runs of the same fabric design are produced on a roller print cylinder machine operating at speeds between 50 and 100 yards a minute. As many as 10 different colors can be printed in one continuous operation, but each colour must have a separate roller. The design is cut into the surface of copper rollers; by varying the depth of the engraving on the roller the shade depth can be altered. Sharpness of line and fine detail can be achieved this way. A typical printing machine has a large padded drum or cylinder, which is surrounded by a series of copper rollers, each with its own dye trough and doctor blade that scrapes away excess dye.
The tubular screens rotate at the same velocity as the fabric, the print paste is distributed inside a tubular screen, which is forced into the fabric as it is pressed between the screen and a printing blanket (a continuous rubber belt). It picks up colour from the engraved area of each roller in sequence. The printed cloth is dried immediately and conveyed to an oven that sets the dye. Knitted fabric is mostly printed in this method as it does not pull or stretch the fabric.
Roller Printing Flat (Silk) Screen Printing Rotary Screen Printing Block Printing Heat Transfer Printing Dye Sublimation Printing Resist Printing
Exposing m/c Curing m/c Heat transfer m/c
Design: - printing design means colors separate to the design. Printing size , grading system , measurement then design pass to the expose section. Expose :-Design pass to the screen heat transfer to the expose machine , screen is the mesh fabric the machine can per from through high function vacuum pumps that saves time for screen preparation. Exposing Machine that is specially designed to enable the fine screen to be exposed. Imported sealed rubber blanket and filtered air regulator is used to keep the machine dust clean. The Machine is a specially designed for enable the fine screen to be expose The Machine can perform high function (imported) vacuum pumps. Instant vacuum leads to save time for screen preparation. The machine consists indigenous quick start espousal systems, the light is very strong and stable Machine adopts many rows of powerful homogeneous distribution UV light source, economic and save energy. The Imported sealed rubber blanket. Filtered Air Regulator Heat &+ Keep Dust clean
Steps in design to screen:- Screen mode (50-60 min dryer temp 70 c) ↓ Exposing m\c ↓ Cold water (5 min) ↓ After them spray gun develop ↓ Dryer (30-40 min) ↓ Re-wash ↓ Dryer (20 min) ↓ Re-expose (20 min) ↓ Hard & applied. ↓ Design complete
Difference between Automatic Print & Hand Print:- Automatic Print Hand Print 1. Accuracy 1. No Accuracy 2. Limited Production 2. No Limited Production 3. Production is high 3. Production is Low 4. Depends on m/c capacity 4. It is manually print 5. Capacity is 9 colors 5. Variety colors print
Block Printing Block printing is a traditional process dating back to India in the 12th century. Wooden blocks made of seasoned teak in different shapes and sizes are cut by trained craftsmen. Each block has a wooden handle and two or three holes drilled into the block to the passage of air and release of excess print paste. Fabric is stretched over a printing table and fastened with small pins. Printing starts from left to right, first the colour is evened out in the tray and then the block is dipped in. Then the block is applied to the fabric with careful registration and pressure is applied.
Dye Sublimination Printing Dye sublimation allows photo lab quality picture printing. During the dye sublimation printing process, an image is digitally printed in reverse with dye sublimation toners or inks onto media. That image is then placed on top of a fabric and subjected to high heat and pressure to form a heat press. The dye sublimation toners or inks sublimate – the inks go from a solid state to a gaseous state without becoming liquid in between and flow into the fabric, dyeing the threads. This creates a gentle gradation of colour and does not distort or fade over time.
Heat Transfer Printing This is essentially transferring an image to fabric from a paper carrier. When heat and pressure are applied to this paper the inks are transferred. Some transfers are topical, and the image sits on the surface of the fabric. Other transfers are absorbed into the fibres of the fabric. Heat transfer printing is clean and environmentally safe. The only by-product is the paper carrier. It is the perfect print method for short run and sample production, but can also be used for batch production as well.
Batik Although experts disagree on the origins of Batik, it is very popular in Indonesia and Africa. The cloth that is used for batik is washed and boiled in water many times before the wax can be applied so that all traces of starches, lime, chalk and other sizing materials are removed. Before modern-day techniques, the cloth would have been pounded with a wooden mallet or ironed to make it smooth and supple so it could receive the wax design. The designer uses a ‘tjanting’ (wax pen) to draw the design on the cloth. The wax is kept fluid in a melting pot. After the wax has been applied, the fabric is ready for the dye bath. Today most batik factories use large concrete vats, above the vats are ropes with pulleys that the fabric is draped over after it has been dipped into the dye bath. The amount of time it is left in the bath determines the hue of the colour (longer for deeper colours)
Direct Print Also called application print. Design is printed directly onto a white cloth or a previously dyed fabric. They are the most popular print types.
Discharge Print Fabrics are dyed a solid color prior to printing. When printing is done, the design is applied by screen or roller with a chemical which removes the color of the originally dyed fabric. Discharge prints can be made with rollers and screen methods. They are not widely used because production costs are high.
Resist Print It involves a two step procedure: (1) printing a pattern design on a white fabric with a chemical that will prevent penetration of dyes; and piece dyeing the fabric. The result is a dyed background with a white patterned area.
Blotch Prints It is one in which the background color is created by printing rather than dyeing. The ground and pattern design colors are printed onto a white cloth. One of the problems with blotch prints is that large background color areas of the print are not covered with the full depth of color.
Warp Prints This involves printing the warp yarns of a fabric before weaving. The fabric is woven with a solid color filling, usually white. The result is a soft, shadowed, blurred design on the fabric. These prints are found on high quality, costly fabrics because it requires careful, meticulous labor.
Flock Prints Tiny particles of fiber are made to adhere to a fabric surface in conformance to a particular design. Rayon and nylon fibers are typically used for flocking. The ability of flocked fibers to withstand dry cleaning and/or laundry depends on the adhesive. Adhesives with excellent fastness to cleaning processes are used.
Burn-out Prints 1. This involves printing with a chemical that will destroy the fiber in the patterned design print area. 2. In fabrics that are made with blended yarns, the burn-out chemical will destroy one fiber and leave the other undamaged. Unusual and interesting fabrics can be created by this method.
Duplex Prints These are fabrics in which both sides of the fabric are printed. They are made to imitate more costly woven yarn-dyed design effects such as stripes, checks and plaids.They are rarely used because of the high cost of printing both sides of a fabric
Chemical in use:- Magic color :- Variotherm in use. Only for pigment & base fabric just white & light color just heat fabric print reduces, cold then fabric prints in show. Chemical in use:- Variotherm & pigment. Color in use. Time :- 7.5 pieces/min. Fault :- Color shade Design Placement design ok
Metallic print :- Metallic print is the powder from then mix if any color & print. Chemical in use:- Base - 200 Powder 5-10% Color in use. Time :- 7.5 pieces/min. Fault :- Color shade Design Placement design ok.
Glitter print:- Glitter is the powder from. fixer must be use. Chemical in use:- Binder - 100 Glitter powder ----- 30-50 Color in use. Fixer— 1-2 % Time :- 7.5 pieces/min. Fault :- Color shade Design Placement design ok Fixer can not be use then glitter is damaged print.
Puff print:- It is chemical character. It is imbues mesh. Chemical in use:- Base & clear minimum - 50 White if need -100 Color in use. Time: - 2 pieces/min. Temp- 170 c Fault:- Color shade Design Placement design ok Gum mistake then flock mistake.
Foil print:- Print some pattern with the foil on the fabric or paper for shinny effect. Foil print is the foil paper. it is heat transfer Chemical in use:- Gum mix binder. Heat press foil. Time 10-15 sec & temp -160-165 c Time: - 7.5 pieces/min. Fault:- Color shade Design Placement design ok Gum mistake then foil mistake& heat problem then print problem.
Flock print :- The flock technique of printing designs with an adhesive and sprinkling with fine bits of wool or silk was probably first adapted to wallpaper. fiber dust use with gum. Chemical in use:- Powder with gum. Fixer add gum Fixer-1% & gum-100% Time :- 7.5 pieces/min. Fault :- Color shade Design Placement design ok Gum mistake then flock mistake
Discharge :- Discharge means out of fabric colors. Activator must be use. Chemical in use:- White & clear. Activator -->6-10% Time :- 7.5 pieces/min. Fault :- Color shade Design Placement design ok Fabric must be discharge. White fabric is no print.
Oil base plastisol :- It is oil soluble. It is sari cal thinner; it is oil to which other oils or substances are added to produce a lubricant. Chemical in use:- Seri cal thinner. Oil base color. Time :- 7.5 pieces/min. Fault :- Color shade Design Placement design ok Seri cal problem then print problem.