Comparing rolar and rotary printing

This slide shows the difference between and brief explanation of roller and rotary printing

1. Comparing Rotary & Roller Printing

2. Content Roller Printing Rotary Printing Comparing of Both Engraving Process Printing Process Squeezing Mechanism Comparing Machine Advantages and Disadvantages Conclude

3. Roller Printing The printing of textiles from engraved copperplates was first practiced by Bell in 1770. Each color of the design requires a separate cylinder. Sometimes referred to as cylinder or machine printing. Engraved roller printing is a modern continuous printing technique developed in the late 19th and early 20th century. Until the development of rotary screen printing, it was the only continuous technique. In this method, a heavy copper cylinder (roller) is engraved with the print design by carving the design into the copper. It was entirely obsolete.

4. Rotary Printing Rotary screen printing is a continuous printing process. A perforated cylinder or spherical screen are used which are automatically fed with paste from inside by pump and paste pass through perforation. The screen is produced by photochemical means, in that a photopolymer coating is applied to the surface of the screen. A typical rotary screen print machine would have an in-line configuration with upwards of seven or eight print stations available, each printing one color. The cylindrical printing screen itself is a very fine ‘honey combed’ type mesh.

5. Comparison of Engraving Department Roller Printing In which we Engrave by mechanical and chemical then coat with chrome for Durability of screen and copper is soft. In which we use different type of chemical for etching and mechanical process also available. Laser engraving also use. If we Engraved the roller for one design, then it can’t be use for other design. In which engraved Portion give the design. Engraving of roller is expensive. In which there no mesh problem for printing. It engrave give less fine design. Rotary Printing In which we engraved by laser, Manually, Ink jet and wax and no requirement of coat because nickel is durable and prover cad system. In which there is chemical etching method used for engraving. In this case screen is reusable for other design because photoelement easily washable. In which engraved portion give design by pressure of paste through perforation. Engraving of roller in inexpensive. In which mesh have very important for design (toner, fine). In which we obtained more fine design.

6. Comparison of Engraving Department Roller Printing In which there is no effect in coating on design because design is engraved portion. For photoengraving we must make positive and negative image for etching on roller for required design and separation of color. In which in case of photoengraving we use same process as such rotary screen but after exposing of masked screen to light then we dip the copper in acid and un-exposed area remove the chemical and etch copper because copper is sensitive for copper. The depth of scales depend upon time duration in acid of screen. After that we remove the photochemical by mineral and then coated. Rotary Printing The quality and thickness of the coating on screen are determined by the down-ward movement of the squeegee speed, viscosity of the lacquer, squeegee diameter, rubber hardness and rubber thickness In rotary this process is also same and separation of color. In this case we washed the un-exposed area with help of hot water we don’t need acid. The depth depends upon the layer of photochemical. In we don’t remove the chemical from every part of screen on masked area and then cured.

7. Comparison of Printing Process Roller Printing In which we set the screen according to color depth for printing because of color contamination. In which paste is taken from color box evenly spread on roller for printing. In which color doctor evenly spread the color and lint doctor remove the contamination. Design is print on fabric from engraved portion by pressure. It can print woven and tricot fabric. Rotary Printing In which there is no setting of color according to depth but in certain designs, particularly those containing tonal areas, it is advisable to print one color on top of another. In which past is evenly spread inside the roller and squeegee system work. In this case there is no lint doctor and color doctor use for pressure the paste through perforation. In which design is print from perforation. It can print woven and knitted fabric.

8. Comparison of Printing process Roller Printing In which large design can not be print wide 1.8m. In which maximum 15 color can be print and lack of freshness of design. In this case (?) In which temperature of dryer is maintained because This is particularly critical for designs in which a high proportion of the total area is printed (high percentage cover). Rotary printing In which there is no problem of large design and large repeat can also be print by Zimmer. In which 16-32 color can be print and there is no problem of freshness of design. Sometimes more than one pass is required to achieve uniformity and adequate penetration of paste for irregular and thick fabric. In some machines the squeegees this fills the mesh in the printing areas of the screen with paste before the screen touches the fabric. In this temperature of dryer also have same importance

9. Squeezing Mechanism Roller Printing In which there is no squeegee system for printing just press the roller on fabric. Pressure of roller is very crucial for same color of print in it. In which there is problem of impression of design because to the mandrel ends inevitably produces some bending and the fabric edges tend to be printed more heavily than the middle. In which above problem solve making more lapping in center for continuous impression. In which problem of changing the roller time which 50% of working time of production of printed fabric. In which contact time and pressure of roller with fabric show the paste flowing. Pressure of roller is high. Rotary Printing In which there are many squeegee system like conventional, air and magnetic squeegee. Pressure of roller is not crucial for printing same depth impression. In which If the squeegee pressure is uneven, the volume of print paste applied across the width will vary, resulting in an unlevel appearance in the final print. The Zimmer brothers used the magnetic-rod squeegee system in their rotary machines which solve the problem. In which there is no such problem. In which pressure, pore size of screen, kinetic motion of paste has direct effect on the quantity of paste flowing through a screen and fabric type. Pressure of roller is not high

10. Comparison of machine Roller Printing In which we use roller for printing. In which color is taken from furnishing roller. In which pressure bowl play important role in printing and roller print around it. In which fabric move with help of roller drive and pressure bowl. In which continuous use of blanket must replace. Skill of operator is good. In which lapping is required for even printing. In which no adhesive material used to make contact the fabric with bowl. In which there is less penetration of past because forcing the paste by pressure. Rotary printing In which we also use roller, but perforation is used for printing. In which color is take with help of suction pipe from tank of color. In which we use belt for printing and roller print on it. In which fabric move with the help of belt. In which blanket is continuously washed under the conveyer belt. Skill of operator is not good. In which there is no use of lapping. In which adhesive material is used for making fabric contact with blanket. In which there is no such problem.

11. Roller Printing Advantages High production Upton 16 colors can be used Complex designs are possible Fine vertical lines can be produced Can be used for printing any style Sharp lines can be produced Floral designs can be produced Disadvantages Lack of freshness of the design Large design (wider width not more than 1.8 m) is not possible Horizontal lines and large blotches are difficult to produce If back grey is used, then stitch impression Sequence of colors printed (light colors earlier than darker) Higher coloring effect not possible Design change time is high Lower production in case of more colors Engraving of rollers is expensive Not suitable for short runs

12. Rotary Printing Advantages It needs relatively cheap equipment. It has very few preliminaries. This  type of printing  permits printing on almost any surface. Areas of far greater size can be stenciled. Frames 1.27m X 1.52m (50” X 60”) are frequently used for textile printing. Surface to be printed need not be flat. It give high production than roller. Can be used for printing any style Sharp lines can be produced Floral designs can be produced Disadvantages Not suitable for small scale Not environmentally friendly because this method used lot water and drain of chemical. This arises from inaccurate screen placement or fabric movement, from the fabric slipping on the blanket because of poor adhesion, or from distortion of the screen mesh by the drag of the squeegee.  Off-contact printing cause the splashing of color. When printing consecutive screen repeats, the screen frame inevitably falls on part of the area most recently printed and may leave an impression.

13. Conclude