“Develop success from failures. Discouragement and failure are two of the surest stepping stones to success.”
Printing from Hot Metal Type is generally called Letterpress printing. Until the middle of 19th Century L/P was the only commercial method for putting ink on paper, even until the middle of 20th Century, it was still being used to print newspaper book, magazines, and most commercial printing. Letterpress is based on the concept of relief printing.
Designed in 1950, the platen Jobber became the most common type of Letterpress used in US.
Type of Presses:
Platen Press: 11"x17", 17 x 22"
Rotary Press: for newspaper and magazines use stereotype, electroplates.
Flong- for casting streo-plates.
Wax mold: for electroplates
Image carrier: Type-form - cast type
Stereotype- plate1
Electrotype-plate
1885-1890: Linotype, Monotype
Zine blocks copper blocks or engravings.
Substrates: Mostly paper, folding Cartons, Cardboard material and textiles like book binding cloth.
Inks: Linseed oil or varnishes. Petroleum baked inks, require denser ink, heavier in pigment.
UV and water-based inks.
Press Technology:
Flatbed presses
Rotary Screen Presses
Cylinder Presses.
Flatbed press: use flat screens that require back and forth motion. used for printing graphic applications such as bill boards, posters, t shirts, banners and caps, some presses have vaccum table which improves print quality and registration, Manual, semi-automatic fully automatic.
Rotary: use screened cylinders with the squeezer mounted inside the cylinder, Ink is pumped automatically and the squeezee controls the flow of ink used to print continuous pattern like gift wrap, textile, thin paperboard, and wall covering vinyl. Have multiple printing units.
Cylinder: Have configuration similar to offset, flexo and gravure. A series of grippers grab the sheet which is held tight to the cylinder by a vaccum. As the cylinder rotates, the screen carriage passes over the substrate; the stationary squeeze
LETTERPRESS PRINTING: The term letterpress brings to mind images of raised letters pressing against a surface, onto which their shape is transferred in ‘ink’, letterpress printing is also called relief printing.
Types: letterpress printing is meant for printing text comprising of not only letters but also other visual such as borders, rules and illustrations in black and white or color. Other visual can also be made separately and then arranged together on a page or pages. Then, a form can be made for printing.
There are three types of processes involved in letterpress printing.
1. Plane to plane surfaces (flat to flat).
a. Hand press.
b. Platen machines.
2. Plane to cylinder (flat to cylinder).
a. Stop cylinder machine.
b. Two revolution cylinder machine.
c. Swing cylinder machine.
d. Single revolution cylinder machine.
e. Reduced stop cylinder machine.
3. Cylinder to cylinder (rotary machine).
a. Platen press: the platen press takes its name from the platen, which is one of two plain surfaces on which paper is placed for printing. The other surface on which the arranged images (forms) are locked firmly, is known as the image carrier. Inking is done by ink rollers, which up ink from a revolving disc fixed above the machine and then pass it across the forme. Paper is fed by inserting it between the two flat surfaces. These surfaces are brought together to print the required image. This output is taken out in the form of printed paper from the machine when the two surfaces are open or separated. The feeding and delivery system of the platen press may be automatic or hand operated. The platen press is slow, but it is well-suited for printing letterheads, cards, bill-forms, small format booklets. It can also be used for embossing, die-cutting, creasing, perforating, and hot-foil stamping.
b. Plane to cylinder: the first development of the flatbed cylinder press came as many as 350 years later than the invention of the platen press. The credit for it goes to Frederick Koening of Germany. It had two features- 1. The press was operated by stream power, 2. One of the printing surfaces was cylinder, that is, the surface the type forme remained flat on a bed while the ink rollers rotated over it and a cylinder was used to roll over and press the paper against it. The cylinder function, while revolving the ink applied on the matter of the bed gets transferred to the paper through the pressure of the cylinder.
c. Cylinder to cylinder: letterpress printing improved further when both the printing surfaces were made cylindrical. There in lay the beginning of the rotary press and high-speed printing. The type forme in a rotary press is converted into a cylindrical plate and another cylinder is rolled against it. The paper passes between the two cylinders.
It is faster and the continuous action of the cylindrical image carrier.
A rotary press require elaborates make ready procedures before printing can begin. To achieve this, the copy is set on a hot metal composing system and block are made for illustrations, etc. and then arranged according to the layout plan on a metal frame called chase. Now, the paper flong with depressed images is fed into a casting box where it is converted into a lead version, called a stero.
EQUIPMENT OF PRINTING DEPARTMENT: These main material required in letterpress printing department.
1. Material used for tightening the matter: some special instruments are required to tighten matter in the chase, beside the matter there is some vacant space in the chase. This space has also to be filled to 1 to 10 em in breadth and different length).
a. Furniture:
1. Wooden furniture: 60 em long and one em to 8 or 10 em in breadth.
2. Cast iron furniture: length 8 em to 60 em and breadth is 2em to 10 em.
3. Inter locking furniture: this is used for large vacant space filled in the chase. It is made of solid iron. 8em to 72em long and 2em to 4em broad. Other besides this furniture made of aluminum, plastic and Bakelite.
b. Load: this used when space less than 1em. It height is 1.92cm and it is prepared from 1.5 to 3 point.
The length is 45cm for hand machine and 60cm for automatic machine.
c. Reglet: it is made of wood and work like lead. It thickness is form three to twelve Point and length according requirement.
d. Quatations: these are square pieces of metal. It is also used for fill up space between two furniture while empty space between small matters.
2. Quoins: these are used for tightening the matter. For each page mater at least two or more quoins are required according to the need.
a. Wooden quoins:
b. Hemple quoins: these are two wedge shaped iron pieces. In both the pieces, teeth are found on one side, leaving a little plane part in it. These two teethed pieces are put together and a key is placed in between the teeth with facing each other. When this key is rotated, both these pieces quoins slide in opposite directions. In this way the breadth of the quoins goes on expanding.
Some mechanical quoins are named
c. Wickersham quoins: the special key is placed in this groove. Both parts are connected by two springs. The key is kept in the groove and turned in the clock-wise direction. The expansion can be made the most upto M points.
d. Noting quoin:
e. Safety or precision quoins:
f. Super quoin:
g. Expansion job locking quoins:
h. Register quoins:
i. Bar book quoins:
3. Chase: this is a frame made of iron. The matter to be printed is fitted on to it. With the help of some other materials. These frame are different types.
a. Cast iron: if the matter is tightened with heavy pressure or falls from a height.
b. Wrought iron: this is not use generally.
c. Steel case: this is best type of chase. Neither can they expand nor there a danger of their breakage.
4. Galley: this is square tray in which there are walls on three sides and the fourth side is plane. The matter to be printed is put in it. It is made of steel. Whenever the galley has to be placed in store room, at least it is upper surface should be smeared with oil, otherwise it will get rusted.
5 .Imposition surface: another old name for it is imposition stone. This means, that it is a type of stone on which the matter can be placed and the forme can be fitted on it. The upper surfaces does not have any roughness.
Now – a – days iron imposing surface are being used. It is a rectangular plate made o cast iron.
6. Racks: different types of racks are used for keeping different materials, but steel racks are more durable. The main types of racks are chase rack, galley rack.
7. Cabinet: it is used for tolls concerned with printing machine, proof and paper progress cards of daily work should all be placed in a soft place.
Tools: Many types of big and small instrument are used in the printing department for the preparation of the forme, machine and tightening the forme etc. it is essential for every person who operated the machinery to have a knowledge of these tools. Among the many tools some are described below.
1. Shooting stick: it can be made of wood iron, or horns. The best types is made from iron. It is a rectangular or cylindrical rod about 15 to 20cm long. There are two pointed ends on one side one pointed end is small and beat, the other one is straight and long. This double end is placed on one side of the quoins and struck with a mallet.
2. Planner: this is made of wood in rectangular shape, on its both edges, there is a deep groove along its length. The aim of groove is to make a good grip. It is 15cm long and 10cm broad.
3. Mallet: this is made of wood. It is to strike on the planner for making the matter surface plane, because the upper surface of the type is not strong.
4. Spanner: this is also called wrinches. The groove made in it help in tightening and opening a bolt or a nut. Theses spanner may be different types.
a. L shaped spanner: it resembles the capital letter L. it is used or open and close a bolt.
b. Box spanner: it has inner side groove of different sizes according to the size of the bolt. The bolt is fitted into groove. The bolt can be opened or tightened by turning its handle.
c. Ordinary spanner: it has a groove at both ends in which the nut or bolt can be fitted.
These spanners are available in different sizes separately and also in sets.
5. Oil can, oil gun and grease gun: it used for all part moves smoothly.
6. Screw driver:
7. Ink knife: it has a strong steel blade fitted in a wooden handle, ink knives are made in different sizes. The length is even more than 15 to 20 cm.
8. Pins (lays): their technical name in printing is lays. Generally, lays are made of ordinary pins used in paper world. But in printing trade, the word lays has a wise meaning. In each machine, different specific types of lays are used.
9. Roller setting guage: the distance between the type bed and forme roller is measured by this tool. The height of the roller from the bed should be 2.33cm. These guage are of different types.
a. Square Iron gauge
b. Cylindrical roller setting gauge
c. Rollo test
d. Krissan
e. Hartman
f. Corner stone.
10. Tommy: these are made of many types of large and small iron rods. They are used for the opening and closing of some special part of the machine.
11. Paper cutting knife: it also has a strong steel blade. These is a long handle made of wood or ivery. It used for cutting paper.
12. Scissors: their pair of scissors is used for cutting paper and cloth for permanent packing.
13. Immery cloth: immery cloth is used for removing rust.
14. Sand paper: sand particles are sprayed into a strong paper. It is used for rubbing the base of the block.
15. Steel em scale: it is special type of scale. The marks made on it indicates inches and ems.
16. Packing gauge: this looks like a screw guage. The definite thickness of packing papers can be measured by this guage. It is marked in centimeter and millimeters.
Other tools used for perfect packing:-
a. Over lay pin: it is small needle. This is used to make registering holes on the top sheet of the packing.
b. Over lay knife: it looks like a nail cutter. Whereas the nail cutter fully made of steel.it is used to prepare the overlays.
17. Key for tightening the quoins: it used for tightened the quoins and most of the keys are ‘T’ shaped. The key of one type of quoins cannot fit into the other type of quoins.
18. File: these are made from very strong iron. It is many types, some have small grains on them. In all files, these grains are measured by number per square inch.
19. Block height guage: Generally the mount or base of the block is made of wood. Ordinarily, the total thickness of the printing plate and base together is 2.33cm high.
A horse shoe shaped guage is used for this purpose. Another guage which works on the principle of the micrometer guage.
UNIT-2
IMPOSITION AND PLANNING:
Imposition and setting margin:
Imposition: Imposition is the process set of pages sequence for made a section.
Method of working:
1. Half sheet work: in this methods all the pages are imposed in one side of the sheet are contained in one half and those of the other side in other half of the form. Both the sides of the paper are printed form the same form and when cut into half, each sheet producing two complete copies of the job. Also called ‘work and turn’. The sheet are tuned along the longer edge for backing.
2. Sheet work: two different forms are require for printing on each side of the paper. Two side made ‘inner side’ and ‘outer side’ after folded made one complete copy.
3. Work and tumble: all the pages of the scheme are imposed in one forme and both the side of the paper are printed from it. The sheet are turn along the shorter side for registration with same form with contain two complete copies.
4. Work and twist: the same side of the paper is printed twice from the same forme. The sheet twisted around 180 angle. The first print horizontally contain in one half and vertical rules of the pages are contained in other half.
5. Printed first and third: like practical file 1 and 3 page print and 2 and 4 page are print.
Terminology:
1. Oblong page: composing done along the longer edge. (Portrait).
2. Upright: composing along shorter edge (landscape).
3. Section: the printed and folded sheets of paper ready for sewing is called section.
4. Signature: the small alphabet which are printed in single at the left hand bottom corner of the first page of each section are called signature.
5. Inset: the sheet insert in another section.
6. Outset: wrapped around other section.
7. Perfecting: both side registration equal.
8. Recto: right hand page in the facing page of an opened book.
9. Verso: left hand page faced when an opened book.
10. Margin: white area around a printed page.
a. Back margin 1 ½.
b. Fore-edge margin 1.
c. Head margin 2.
d. Tail margin 2 ½.
11. Gutter margin: white space between pages.
12. Cut-flush illustration: bleeding (no margin).
Collating marks: the mark found at back edge of the section for proper gathering.
UNIT 4: Make ready
Make-ready sequence of operations: make ready is a process that start from locking the forme on the machine to start the ok printing.
1. Locking the forme
2. Cleaning and oiling the machine
3. Packing the platen.
4. Setting the inking roller
5. Fixing the forme
6. Taking a proof and adjusting the pressure.
7. Settign the lays on the packing.
8. Setting the frisket
9. Controlling the ink from ink duct.
10. Taking a correct printing proof and then seeking the permission from authority concerned.
11. Placing the printing paper on the feed board.
12. Starting the printing.
We have already discussed about locking the forme, now we are reading next processes.
Packing: the packing is some layer of sheet which is tying-up on the platen or cylinder of the machine. The packing is used for give some extra soft surface between the platen and impression surface. The packing also help to printing on difference paper thicknesses and prevent from break the fine typefaces.
Types of packing: hard packing, medium packing, soft packing, sandwich packing, and extra hard packing.
Parts of the packing:
The top sheet and two or three filler paper should be changed after printing each forme. A pressed impression is made in the top sheet and also two or three filler papers during printing. This pressed packing is not good for another printing forme.
Fixing the rollers:
a. When a roller is removed to cleaning then it’s fitted in the same bracket because all roller have different measurements.
b. The groove of the roller runner has to be fitted properly in the pin of the roller rod.
c. In the platen machine, there is a stud above the roller bracket. This stud can be pressed and the runner of the roller is lifted above the track of the roller. The roller can now easily fit into the socket because socket of the roller is kept pulled back by means of springs.
d. The roller, runner and track should be cleaned and dried properly.
e. All roller should be tightened at an equal pressure with each other and pressure according to steel rollers.
f. All the forme roller should be set equal to the type height by means of a roller setting guage.
Placing ink in the machine: the ink should be applied in the form of a strip uniform on the left edge of the disc and avoid center, right and lower part of the disc. This process is useful because in the beginning the machine has to be operated without impression but each rotation ink comes out from the ink duct and spread on the matter, but impression is off. In this condition, the excess filling on the forme and then in printing. Machine need time to proper grinding so, Ink applied on the left edge of the disc, takes longer time to reach the matter. First rotates the ink roller to proper grinding then locking the form for printing.
Placing the forme on the bed:
a. Make sure forme and bed should be cleared without any dust before printing.
b. Keep the roller at maximum distance from bed.
c. There are two stud present at the lower side of the bed. The forme is placed on the studs.
d. The forme fit from the top side and then tightly clamped.
Adjustment of the Frisket: The frisket is to bring the printed paper without sticking on the forme during printing. Paper sticks to the forme due to tackiness of the printing ink. It also help to check the paper from sliding on the lays. The frisket remains between the matter and the platen while taking impression. It should always be fitted in the non-printing areas. Make sure the position and tightened perfectly of frisket before printing. A care should be taken so that the frisket does not press the lays.
Setting the lays:
1. Temporary lays for short run jobs: First impression taken on the packing of the platen to setting the lays at correct position. Now the full length of the non-printing area of the paper is folded into half. This half folded edge of the paper is placed in such away, that it touches the full edge length of upper edge of the printed matter on the packing. Now the folded sheet is carefully opened without any slip even a little bit. We should take care of the folded paper is properly touching the upper edge of the matter.
The two lays are inserted in the lower edge of the paper placed on the packing for measurement. These lays should be set at an angle of 45 degree to the right side. These are called front lays. Another lay of the left side is also set similar to the front lays and it is called side lay. There are only awlpins used for registration.
2. Permanent lays: those lays which can be used for long run job. 1. Mechanical lays, 2.quad made lays. There are a mechanical lays and other is quad made lays with awlpins used for registration.
a. Mechanical lays: a special type of lays made of brass is used for this purpose. It is very perfect lay to get registration.
b. Quad made lays: it is prepared by a 2 em quad of 12 point size are taken. Each of these quad is placed along with point of the pins and stuck to it with gum or glue. After this, a paper strip are cut, which are as broad as the length of the quad and 5 cm long. Now gum or glue is applied on one side of the paper strip and placed on the quad center part. Now extra strip of paper is stuck on to the packing with the help of other quad. Temporary lays should remain as it were fixed along with the permanent lays to more accuracy. This is not so durable and accurate than mechanical lays.
Preparation of the forme: setting the impression: make sure that ink should be uniform density on the full page. There should be no indentation on the reverse side of the printed paper. Because the packing also needs changes according to the nature of the matter to be printed. Therefore it is essential that while setting new packing, the thickness of the packing should be less than the estimated packing. We can increased the no. of paper of packing according to requirement after first impression.
Technique of setting the impression:
Overlays: first take the impression on white paper and then find out that area which has no ink uniformity and then one or more thin or thick papers have to be stuck on to it. Those areas where having more inks but other parts of highlight areas are cut-off from the printed paper. This sheet is called patch sheet. Sometimes we put a tap on the back side of rules to give thickness. The tapes is comes in different thickness as per requirement. After first proof of a block, prepared the sheet as per requirement with thickness and position. The patch is cut from the near printed edge from four corners of full sheet. That patch sheet is placed on the top sheet of packing and then made the holes in the top sheet and filler papers. The adhesive should be applied on the non-printing areas only. The prepared patch sheet placed under the mount of the block.
Controlling the ink: the ink goes from this ink duct and reaches to the ink disc and then forme rollers. The ink should be dust free, uniform layer, tackiness and long filament. The ink is mixed completely on ink stone by ink knife and then fill in the ink duct. The quantity adjustment of the ink is depends on two function: ink keys and ink duct roller.
Printing permission: after obtaining a perfect printing proof, the permission for commencing the printing work should be taken from the officer in-charge. While printing, the machine should be checked properly, in case there may be some defect in any of its parts, an experienced and skilled worker can judge the defect of the running machine from its sound. Finding the defect of the running machine by its sound, is the right standard of skilful-ness of the worker. If the running machine has to be stopped all of a sudden due to some reason. At that time it should be noted the forme roller should not stay on the forme otherwise the matter and the roller both may become defective.