A flexographic print is made by creating a positive mirrored master of the required image as a 3D relief in a rubber or polymer material. A measured amount of ink is deposited upon the surface of the printing plate (or printing cylinder) using an engraved anilox roll whose texture holds a specific amount of ink. The print surface then rotates, contacting the print material which transfers the ink.
One method of plate development uses light-sensitive polymer. A film negative is placed over the plate, which is exposed to ultra-violet light. The polymer hardens where light passes through the film. The remaining polymer has the consistency of chewed gum. It is washed away in a tank of either water or solvent. Brushes scrub the plate to facilitate the "washout" process. This method is considered "old-fashioned," but is still widely used in smaller operations, and is still taught in most high school and college flexo programs.
Originally flexographic printing was basic in quality. Labels requiring high quality have generally been printed using the offset process until recently. In the last few years great advances have been made to the quality of flexographic printing presses.
The greatest advances in flexographic printing have been in the area of photopolymer printing plates, including improvements to the plate material and the method of plate creation, usually photographic exposure followed by chemical etching, though also by direct laser engraving.
Digital direct to plate systems have dominated the industry recently with their better resolution and the ability to print four color process (or more) as well as offset. Companies like Dupont in DE and PlateCrafters in Colmar, PA have pioneered the latest technologies with advances in FAST washout and the latest screening technology, even companies who make plates in house are going to trade shops to get these high quality plates.
Laser-etched anilox rolls also play a part in the improvement of print quality. Full color picture printing is now possible, and some of the finer presses available today, in combination with a skilled operator, allow quality that rivals the lithographic process. One ongoing improvement has been the increasing ability to reproduce highlight tonal values, thereby providing a workaround for the very high dot gain associated with flexographic printing.
Flexo has an advantage over lithography in that it can use a wider range of inks, water based rather than oil based inks, and is good at printing on a variety of different materials. Flexographic inks, like those used in gravure and unlike those used in lithography, generally have a low viscosity. This enables faster drying and, as a result, faster production, which results in lower costs.
Printing press speeds of up to 600 meters (2000 FPM) per minute are achieveable now with modern technology high-end printers, like Flexotecnica [1], which introduced the world's first 12-color central impression (CI) drum press at Drupa 2008. Other press formats, such as in-line and stack presses, are available from Tresu and other suppliers.
History
The process of flexography was originally called “aniline printing,” named for the aniline oil used in the ink. In 1890, the first patented press was built in England by Bibby, Baron and Sons. The water-based ink smeared easily, leading the device to be known as “Bibby’s Folly”. In the early 1900’s, other European presses were developed using rubber printing plates. But by the 1920s, most presses were made in Germany, where the process was called “gummidruck”.
During the early part of the 20th century, the technique was used extensively in food packaging in the United States. However, in the 1940’s, the Food and Drug Administration classified aniline dyes as unsuitable for food packaging. Printing sales plummeted. Individual firms tried using new names for the process, such as “Lustro Printing” and “Transglo Printing,” but met with limited success. Even after the government approved the aniline process, sales continued to decline. Intent on re-popularizing aniline printing by changing its name, Franklin Moss, president of Mosstype Corporation, surveyed the industry in 1951 and received over 200 different name suggestions. In October of 1952, the new name was announced; “flexography.”[1]
Products
Typical products printed using flexography include brown corrugated boxes, flexible packaging including retail and shopping bags, food and hygiene bags and sacks, flexible plastics, self adhesive labels, and wallpaper. A number of newspapers now eschew the more common offset lithography process in favour of flexo.
In education
The Flexo in Education Program, formerly The Flexo in High School Program, was started at South Mecklenburg High School in Charlotte, North Carolina by the Flexographic Technical Association in 1993. Since its inception many other high school programs have been started. For example Asheville High School in Asheville, NC, The Applied Technology Center in Rock Hill, SC, Fort Mill High School in Fort Mill, SC, and others. The program has even gone international with the inclusion of Gordon Graydon Memorial Secondary School in Missasauga, Ontario Canada. The program was re-named to become The Flexo in Education Program because post-secondary institutions began to participate in the program. Many technical colleges and universities incorporate flexography into their curriculum. For example The Department of Graphic Communications and the Clemson University Printing and Converting Research Center at Clemson University, Central Piedmont Community College, Chowan University, Appalachian State University, the Graphic Communications Management program at Ryerson University, and others include flexography in their curriculum.
Sadly, Charlotte-Mecklenburg Schools, the school district where Flexo in Education got its start, announced in 2008 that the first ever Flexo in High School program at South Mecklenburg High School would be discontinued. The building where their flexography lab was located was demolished Monday, July 7, 2008, to make way for a new 3-story building to house the school's science and technology department. The school district determined that it would be too difficult and expensive to move, store, and re-install press and equipment in the old lab. It was, instead, donated to another school in North Carolina to start a new flexo program.
Flexographic printing inks
The nature and demands of the printing process and the application of the printed product determine the fundamental properties required of flexographic inks. Measuring the physical properties of inks and understanding how these are affected by the choice of ingredients is a large part of ink technology. Formulation of inks requires a detailed knowledge of the physical and chemical properties of the raw materials composing the inks, and how these ingredients affect or react with each other as well as with the environment. Flexographic printing inks are primarily formulated to remain compatible with the wide variety of substrates used in the process. Each formulation component individually fulfils a special function and the proportion and composition will vary according to the substrate.
Print Process Descriptions:
Printing Industry
Flexographic presses are capable of producing good quality impressions on many different substrates and is the least expensive and simplest of the printing processes used for decorating and packaging printing. The use of flexographic printing presses is on the rise. There are two primary reasons for this: 1) it is a relatively simple operation; and 2) it is easily adapted to the use of water-based inks. The widespread use of water-based inks in flexographic printing means a large reduction in VOC emission compared to the heatset web or gravure printing processes.
Publication flexography is used mainly in the production of newspaper, comics, directories, newspaper inserts, and catalogs. Packaging flexography is used for the production of folding cartons, labels, and packaging materials. Large quantities of inks are used during normal runs on flexographic presses; however, some printers are able to recycle a majority of their spent inks and wash waters. Major chemicals used in flexography include platemaking solution, water and solvent based inks, and blanket/roller cleaning solvents.
Flexography is a form of rotary web letterpress, combining features of both letterpress and rotogravure printing, using relief plates comprised of flexible rubber or photopolymer plates and fast drying, low viscosity solvent, water-based or UV curable inks fed from an "anilox" or two roller inking system. The flexible (rubber or photopolymer) plates are mounted onto the printing cylinder with double-faced adhesive. Plates are sometimes backed with thin metal sheets and attached to the cylinder with fastening straps for close register or ink alignment. This adds additional cost to the plate and requires more makeready time, but when quality printing is critical this type of plate can make the difference.
DIFFERENT TYPE OF PRINTING MACHINES
Now a days a various types of machines is in use in the market. The main purpose of no doubt is printing but for various items various type of machines are used. fes instances are given below.
SOFT PRINTING MACHINES
SOFT
PRINTING
MACHINE
Model
HSR-320
C Type
Characteristics:
1.Adopts ceramic mesh roller to convey ink.
2.Magnetic powder brake and slutch control the feeding and rolling or discharging. It can be equipped with automatic color register controller.
3.Each printing unit adopts 360-degree registering adjuster.
4.Each printing unit is equipped with an assemble of auto infrared drying installation.
5.The inking roller can depart from the machine and rotate at low speed in order to keep the ink from drying when its stops.6.The main motor adopts stepless governor converter.
7.This machine can finish processing one web from feeding,printing polishing,auto infrared druing, laminating and discharging in one processing. The machine is an ideal trademark printing machine for the printing housed to print slips, high grade self adhesive trademarks.
Technical parameters:
Printing speed(m/min) 50
Printable color 4 colors
Max Web Width(mm) 320
Max printing width(mm) 310
Max feeding diameter(mm) 600
Max rolling diameter(mm) 550
Printing circumference(mm) 175-320
Registering precision(mm) +-0.01
Overall dimension(mm) 2000X1100X2100
Complete Weight(kg) about1800
SOFT PRINTING MACHINE
SOFT
PRINTING
MACHINE
Model
HSR-320
D - Type
Characteristics:
1.Adopts ceramic mesh roller to convey ink.
2.Magnetic powder brake and slutch control the feeding and rolling or discharging.It can be equipped with automatic color register controller.
3.Each printing unit adopts 360-degree registering adjuster.
4.Each printing unit is equipped with an assemble of auto infrared drying installation.
5.The inking roller can depart from the machine and rotate at low speed in order to keep the ink from drying when its stops.
6.The main motor adopts stepless governor converter.
7.This machine can finish processing one web from feeding,printing polishing,auto infrared druing,laminating and discharging in one processing.The machine is an ideal trademark printing machine for the printing housed to prin slips,high grade self adhesive trademarks.
8. Aautomatic error correcting.
Main Technical Parameters:
printing speed(m/min) 50
Printable color 4colors
Max Web Width(mm) 320
Max printing width(mm) 310
Max feeding diameter(mm) 600
Max rolling diameter(mm) 550
Printing circumference(mm) 175-320
Registering precision(mm) +-0.01
Overall dimension(mm) 2000X1100X2100
Complete Weight(kg) about1800
6 COLOURS 900 MM AUTOMATIC FLEXOGRAPHIC
PP. / PE. SACK PRINTING MACHINE
TECHNICAL FEATURES
1. Model: OZ - 4 - 900 Automatic Stack Type
2. Net Printing Width : 900 mm.
3. Maximum Possible Film Width : 1000 mm.
4. Maximum Possible Printing Lenght : Max: 1100 mm , min: 350 mm.
5. Type of ink machine can work: FA series, FX series, FE series.
6. Maximum Possible Printing Speed : 140 m/min.
7. Winding and Unwinding system over motor
8. Babana Roller System will be exist 1 piece each in both winding and unwinding. 9. Uncoiler system tension controlled (Loodcell)
10.Coiler system tension controlled (Loodcell)
11.Automatic PLC control system.
12.The main rollers are rigid chromium plated. 200 microns per dot.
13.Ability of printing from coil to coil.
14.Roller Cylinders movement transfer reduction gear system with AC speed control.
15.5.7 ‘‘ touchable control screen
16.Drying System of 30 kw PLC controlled
17.Main motor with electronic speed control of A.C. 5,5 kw 1500 rpm/min.
18.Stop switch (Enables automatic stopping in case of any breaking of film.) 19.PLC controlled metric measurement indicator.
20.Possible print types (44+0)-(2+2)-(3+1)-(2+1).
21.Winding and unwinding units integrated to machine ( optional )
22.Thickness of cliché: 2,54 mm – 2,84 mm.
23.Manual and automatic operating ability in all situations
24.Main motor movement transfer reduction gear system.
25.Corona Device will be exist before printing.
26.Exhaust fan (Suction fan): 2,2 kw 1500 rpm/min.
27.Pneumatic rigid pallet and pressing system.
28.Electronic solid stade roller PLC heat control.
29.2 pieces of ladders for the use of upper printing groups.
30.Dyeing circulation pumps (Motorpump) 4 pieces.
31.Border control unit.
32.Rail-Winch style system.
33.Electronic PLC control system.
34.Modem connection line.
35.Failure notice parameters.
36.Total electricity load: 48 kw.
37.Total weight of the machine: 6500 kg.
YT600-1000 series Flexographic Printing Machine
MODEL
YT 2600
This is 2 color
Printing
machine
with a
variable
width
adjustment
deviceMain Technical information:
MODEL YT- 2600
PRINTING WIDTH 600mm
PRINTING LENGTH 180-1200mm
PRINTING SPEED 80m/min
PLATE THICKNESS 2.38mm
MACHINE DIMENSION 2300X1600X2200mm
MODEL YT- 2800
PRINTING WIDTH 800mm
PRINTING LENGTH 180-1200mm
PRINTING SPEED 80m/min
PLATE THICKNESS 2.38mm
MACHINE DIMENSION 2300X1600X2200mm
MODEL YT- 21000
PRINTING WIDTH 1000mm
PRINTING LENGTH 180-1200mm
PRINTING SPEED 80m/min
PLATE THICKNESS 2.38mm
MACHINE DIMENSION 2300X2000X2200mm
6 COLOURS 900 MM AUTOMATIC FLEXOGRAPHIC RUBBER ROLLER HDPE PLASTIC BAG PRINTING MACHINE
TECHNICAL FEATURES
1. Model: OZ - 6 - 900 Automatic.
2. Net Printing Width : 900 mm.
3. Maximum Possible Film Width : 1000 mm.
4. Maximum Possible Printing Lenght : Max: 800 mm , min: 260 mm.
5. Type of ink machine can work: FA series, FX series, FE series.
6. Maximum Possible Printing Speed : 140 m/min.
7. Possible Printing Coil Diameter : 800 mm.
8. Possible Maximum Coil Weight : 220 - 220 kg.
9. Uncoiler system tension controlled (Loodcell) 1 piece of magnetic brake.Manual.
10.Coiler system tension controlled (Loodcell) 1 piece of DC Motorized.Manual.
11.5,7 ‘‘ touchable control screen.
12.The main rollers are rigid chromium plated. 200 microns per dot .
13.Printing ability from coil to coil
14.Drying System of 32 kw.
15.Main motor with electronic speed control of A.C. 5,5 kw 1500 rpm/min.
16.Stop switch (Enables automatic stopping in case of any breaking of film.)
17.PLC controlled metric measurement indicator.
18.PLC controlled piece counter.
19.Possible print types (6+0)-(4+2)-(3+3)-(3+2).
20.Cliché cyliders collective move pneumatic system.
21.Thickness of cliché: 2,54 – 2,84 mm. Thickness of cliché sticking band: 0.1 - 0.3 mm. 22.Manual and automatic operating ability in all situations.
23.Measurements : Lenght : 6500 mm, Height : 3800 mm , Width : 1400 mm .
24.Cliché cylinder gear backlash: 5 mm.
25.Exhaust fan (Suction fan): 2,2 kw 1500 rpm/min.
26.Pneumatic rigid pallet and pressing system.
27.Electronic solid stade roller PLC heat control.
28.Airy shaft facility in rolling up and unrolling.3 Pieces (1 piece is mechanic) .
29.Dyeing circulation pumps (Motorpump) 6 pieces.
30.Border control unit.
31.Rail-Winch style system.
32.Electronic PLC control system.
33.Modem connection line.
34.Failure notice parameters.
35.Total electricity load: 55 kw.
36.Total weight of the machine: 8500 kg.
37.Total electricity power : 50 kw
6-Color Flexo Model JXG-6500
Features:
1. Variable frequenecy drive (Taiwan TECO) for regulation. Power saving and easy operation.
2. Both sides printing. If 6 colors, 6 + 0, 5 + 1, 4 + 2, 3 + 3.
3. Printing materials: PE, PP, OPP, BOPP, kraft paper, tissue and other web rolls.
4. All pulling rollers are made of stainless steel to insure
Advantages:
Zero plate bounce:
Print cylinders are locked up in steel clumps, eliminating print cylinder bounce. Plate is fixed by self adhesive tapes.
Precise Impression Control:
Print impression and ink delivery operate independently, allowing the operator to always set a perfect kiss impression for better print quality.
Capable to print on web paper and even tissue:
If to add automatic tension controller and ceramic anilox. Giant unwinder and rewinder is available.
OTHER TECHNICAL DATA
No. MKW-M1
Name 6-Color Flexo
Model JXG-6500
Size 20"
Print Width 500mm
Print Length 1,000mm
Print Speed 10-70 m/min
No. MKW-M2
Name 6-Color Flexo
Model JXG-6650
Size 25"
Print Width 650mm
Print Length 1,000mm
Print Speed 10-70 m/min
No. MKW-M3
Name 6-Color Flexo
Model JXG-6750
Size 30"
Print Width 750mm
Print Length 1,000mm
Print Speed 10-70 m/min
No. MKW-M4
Name 6-Color Flexo
Model JXG-61000
Size 425"
Print Width 1000mm
Print Length 1,000mm
Print Speed 10-70 m/min
6 COLOR PRINTING MACHINE YT-61000
Use:
it uses sensitization resin as flexible printing plate, suitable for printingsuch packing materials as polyethylene, polypropylene bag, cellophane and rollpaper. It is a kind of ideal printing equipment for producing paper packing bag forgood, supermarket handbag, vest bag and clothes bag. Performance and characteristics:
1) Easy operation, flexible starting, accurate color register
2) The meter counter can set printing quantity according to the requirements. Stop the machine automatically at the quantity or when the material is cut off
3) Pneumatic printing cylinder lift and lower, it will stir the printing ink automaticallyafter lifting 4) The printing ink is spread by the cylinder with even ink color
5) Reliable drying system coordinated with high-speed rotation, it will automaticallybreak circuit when the machine stops
6) 360°continuous and adjustable longitudinal register device
7) The frequency control of motor speed adapts to different printing speeds
8) There are jogging/stopping buttons on the plate roller base and material rollingrack so as to make it easy operate the machine when the plate is installed
Main technical variables:
1) Type/item:YT-61100
2) Printing entrance width:1100mm
3) Printing width:1060mm
4) Length of printing product: 191 ~ 194mm
5) Diameter of roll material: 455mm
6) Printing speed: 5 ~ 50m/min
7) Thickness of printing plate: 2.3mm
8) Total power:21kW
9) Overall dimensions (mm): 3,900 x 2,160 x 2,950
10) Weight (kg):5,500
