Thursday, October 29, 2009
Monday, April 13, 2009
Judge a book by the Cover!
What you need to know while choosing Book Covers
In most cases, the design of the book cover is a designer/artist’s job. The publisher takes plenty of effort in the design of the book cover, which improves the salability, and shelf appeal of the book. The illustrations, photographs and designs on the cover are alloted a lot of importance; a huge number of hours are spent on discussing and designing the cover.
All these efforts can come to a naught, if the same attention is missing in selection of the material for the cover. Many of the publishers are aware of the important points to be considered while selecting the cover material/paper. However, some will give undue importance to aesthetics while ignoring the need to crease/score the covers. And finally there are others who will opt for cost over grain direction.
Let us discuss the considerations for choosing the “right cover” for a perfect binding job. Generally, the covers are thick, printed, embossed, laminated papers or boards. While selecting the cover materials, the following properties are to be considered :
* Thickness and size of stock
* Grain direction
* Suitability for creasing / scoring
* Splitting strength
* Inside surface properties
* Stiffness and trim strength.
1. Thickness & Size of Stock: Using a thick board to bind a thin book block is a strict "No No". The cover weight (gsm) is directly proportional to the book thickness. Please consider the guideline in the table below:
Book block thickness (in mm) Cover thickness (in gsm) *
Up to 5 mm 150 - 180
6 to 12 mm 200 - 230
13 to 16 mm 250 – 270
More than 16 mm 300 - 350
The spine length of covers should be foot plus 3mm and head plus 2mm, meaning that an additional 5mm longer that the book block.
* There are other factors like stiffness that need consideration while selecting the cover weight.
2. Grain Direction : The grain direction of the cover should be parallel to the book spine. This is absolutely necessary for a ‘well bound’ book
3. Suitability for Creasing / Scoring : A lot of stress is put on the cover board when it is scored. The two centre scores are necessary for achieving a square spine. The outer creases/scores are known as ornamental or opening creases and they power the opening of the covers. The scoring/ creasing lines, achieved through discs on the perfect binder, should not break the cover surface. Conversely, the cover should not be too thick for the scoring discs to create any impact. In cases, where the ornamental scores are not deep enough, the load of opening will shift to the second and third page and this can break the joint.
4. Splitting strengths : Splitting is a case where the outer layer of the cover comes off the next layer. When splitting occurs on the spine area or at the trimmed edges, it could have disastrous results. Cover materials are fabricated through different methods like couching (pronounced as ‘cooching’) or gluing of several thick layers. Couching is a process of attaching two or more paper webs into one layer, when they are moist, during the paper manufacturing. There is no glue used in this case. Hence couched type paper will have better split resistance when subject to moisture. Also, a high splitting strength will reduce the possibility of wrinkles on the book spine. It is ideal to make a few dummies with the available cover material and compare the results.
5. Inside surface properties: The surface of the inside cover is the one that comes in contact with the glue. There should not be any lamination or lacquer at the spine and side glue areas. Glossy cover should be tested for compatibility with the hot melt adhesive used.
6. Stiffness and trim strength: Extremely stiff covers will not travel well on a perfect binder. The same is true for very thin and highly flexible covers. In certain cover material, the coating, ink, lamination etc peel off at the edges during trimming. This means the paper layer will start to split. This is due to a low trim strength of the cover material.
There are few more points to be considered while selecting a cover, but the six points (listed above) are the critical ones. I've always believed that print buyers are aware of these criteria and take care of the same while suggesting the cover material. However if they do not, it is the responsibility of the book printer to bring these facets to their notice. If the print buyer still insists on the “wrong choice of cover” for whatever reason, then the job should be accepted with the risk factored in.
Additional care will be needed for setting the machine, in process and final inspection. This will mean more machine and man-hours as well as increased allowance for wastage. A costly affair, right?
Let us disregard the old adage about not judging a book by the cover!
Wednesday, March 4, 2009
End Papering - Tony Clark
END PAPERING :
End Papers are not just the last page of welbound times; as you know. They are leaves of paper glued on to the outside signatures of a book block. The outside end sheets are glued on to the book case, during casing-in.
If any full-production “end – papering” is to be done, either before or in line, on perfect binding machines, the choice of an adhesive or adhesive system to bond the end papers must be chosen carefully. End paper could be printed and they could be bonded to wraparounds or heavily inked areas. A few of them are as given below:
1. The hotmelt film should be pliable enough, to be flatted by the subsequent nipping
2. If the hotmelt is firm and forms a ridge, then the first and last pages will be damaged during the rounding and backing operation
3. Hotmelt should be of very high quality so that it will not be affected by heated joints during the building-in operation*. (* Building –in machine is used for the rapid drying of cased books, by a means of several applications of heat and pressure)
4. Emulsions, if used, should have sufficient tack to be able to have end papers stepped up and to resist twisting.
5. Emulsions also should be easy to clean and yet be relatively fast bonding.
Combined end sheets
In the production of these components, the stretch-bind material should be produced so that at least 25-30 per cent stretch can be gained across the width of the spine. The adhesive bonding the endpapers to the centre lining must be pressed completely flat.
When endpapers with step-up ribbons are used in the first and last units on a gathering machine, the ribbons should be innermost so that they come into contact with the first and the last signatures. This prevents a build-up or a ridge during the lining operation (figure 1).
Rounding and backing unsewn book blocks
The production of book blocks on a standard perfect binding machine is now commonplace. However, a few points should be noted.
Any adhesive used should have sufficient stretch and a reluctance to shrink back. Hotmelts, for instance, should have an elongation of an adhesive film of at least 100 % and the regression should certainly not be more that 30 %.
Note also that the stretch crepe or cloth must have stretchability of more 30%. These figures are given as a guideline, since every country has its own preference regarding the amount of round that a book should carry. In Britain a book has to have a deep round with heavy shoulders, whereas at other places books are generally shoulderless with an attractive round.
Round retention can be judged by taking a book block before rounding and drawing a line across the head. After rounding, another line is drawn between the extremities of the original, which should now be curved. Inspecting the marks on the head of this test book will show how good or poor the round retention is. (Figure 2)
End Papers are not just the last page of welbound times; as you know. They are leaves of paper glued on to the outside signatures of a book block. The outside end sheets are glued on to the book case, during casing-in.
If any full-production “end – papering” is to be done, either before or in line, on perfect binding machines, the choice of an adhesive or adhesive system to bond the end papers must be chosen carefully. End paper could be printed and they could be bonded to wraparounds or heavily inked areas. A few of them are as given below:
1. The hotmelt film should be pliable enough, to be flatted by the subsequent nipping
2. If the hotmelt is firm and forms a ridge, then the first and last pages will be damaged during the rounding and backing operation
3. Hotmelt should be of very high quality so that it will not be affected by heated joints during the building-in operation*. (* Building –in machine is used for the rapid drying of cased books, by a means of several applications of heat and pressure)
4. Emulsions, if used, should have sufficient tack to be able to have end papers stepped up and to resist twisting.
5. Emulsions also should be easy to clean and yet be relatively fast bonding.
Combined end sheets
In the production of these components, the stretch-bind material should be produced so that at least 25-30 per cent stretch can be gained across the width of the spine. The adhesive bonding the endpapers to the centre lining must be pressed completely flat.
When endpapers with step-up ribbons are used in the first and last units on a gathering machine, the ribbons should be innermost so that they come into contact with the first and the last signatures. This prevents a build-up or a ridge during the lining operation (figure 1).
Rounding and backing unsewn book blocks
The production of book blocks on a standard perfect binding machine is now commonplace. However, a few points should be noted.
Any adhesive used should have sufficient stretch and a reluctance to shrink back. Hotmelts, for instance, should have an elongation of an adhesive film of at least 100 % and the regression should certainly not be more that 30 %.
Note also that the stretch crepe or cloth must have stretchability of more 30%. These figures are given as a guideline, since every country has its own preference regarding the amount of round that a book should carry. In Britain a book has to have a deep round with heavy shoulders, whereas at other places books are generally shoulderless with an attractive round.
Round retention can be judged by taking a book block before rounding and drawing a line across the head. After rounding, another line is drawn between the extremities of the original, which should now be curved. Inspecting the marks on the head of this test book will show how good or poor the round retention is. (Figure 2)
The Book - According to Paul Parisi , Interviewed by Sajith
The Book According to Paul Parisi
Paul Parisi is president of Acme Bookbinding, a family-owned Charlestown, Massachusetts-based trade shop and industry icon that specialises in binding books - of all shapes and sizes - as long as the customer wants a quality product. The company traces its beginnings to 1821 and the J G Roberts Company. This makes Acme Bookbinding the oldest continuously operated book
bindery in the world.
Over the years, the company has grown from a one-person basement operation to a manufacturer with a staff of 185 operating in a modern 100,000square-foot facility that has world-class systems and machinery.
Acme binds thousands of single copy hardcover books every day, many of which are for private clients. Acme's hardcover and softcover products can be Smyth sewn or adhesive bound with hotmelt, PUR or PVA. Its products include case binding and paperback binding, textbook rebinding, and library binding. Through one of its divisions, Acme Bookbinding serves printers, publishers, libraries, government agencies and other businesses throughout the United
States. Acme'snewest division, Imaging and Digital Printing, offers facsimile reproduction
of out-of-print books and digital printing of short-run books on-demand.
(http://www.acmebook.com/)
Paul Parisi was in India on a holiday with his family, visiting Rajasthan, Agra, Kerala (God's own country ; Welbound’s too) and Mumbai.
WT met him at Mumbai. Although he was on a holiday, Parisi was keen to keep tabs with business trends in India, the methods of binding / systems etc. He visited Jak Printers at Mumbai, the award winning integrated print house to observe and discuss the state of book manufacturing in India.
Paul Parisi compared notes with Khushru Patel and Aspi ---- of Jak. His passion for book binding technology was massive. He is hands-on, as far as the techniques are concerned. Though Harvard educated, he is proud to call himself a book binder, by profession. The knowledge has been painstakingly created thanks to running a modern book binding house, as well as various
visits of leading book manufacturers world over.
WT : What is the most important equipment in your bindery ?.
PP: We have Kolbus Perfect Binding Lines, Muller Martini hard cover lines, Custom-made “ On Demand case making machines” that can make seven different cases per minute - every case being of a different size, etc, the list goes on. But the most important tool in our bindery does not occupy any floor space. It is our software custom made to oversee the complex operations.
We have 5000 jobs at any given point of time. More than 3000 unique books are delivered in a day. With such a huge variety it's very easy for things to go wrong - unless you have a strong system and a solid software.
WT : In India, its often said, that by the time the job comes to the binder, and the deliveries are required 'as of yesterday'. What is the scenario in USA?
PP: The very same. Fast deliveries are order of the day. This is a world phenomena. I think, trade binderies will have to face the challenge. There have to be systems which support quick turnaround of jobs. That's our specialty. Also, one needs to be careful. We do what we can do to avoid the temptation to break a job and do "need or urgency based supply", (like supplying 100 books out of the thousand book order - and then resetting the job for the remaining number). Instead, we try to run the entire job at one time. Set-up times are very expensive. Most of us do not calculate this in our cost estimate.
WT: What advise can you give to a book binding house, in an emerging market like
India?
PP: There are six mantras.
1 Do not compromise on Quality. The key is quality control systems. We have never lost a customer due to quality problems. It's the most critical aspect of service. When you control your bindery, you control your destiny!
2 Safety should be given paramount importance as well. It has the highest priority in our factory.
3. It's better to invest in new machines, as you will have less spoilage. You will realise that you will need just one "new machine" to take the place of 2-3 old machines. Typically in cases like folding machines, the folding roller pressure, movement of paper etc are important to ensure that good quality printed sheets do not get damaged. This is decided by the quality of parts; and definitely one cannot expect the same from an old machine. In a modern thread sewing machine one can use thinner threads, set up a job in minutes and run at high speeds, adding value to the sewn job.
4. Quality of consumables. For example, the cost of adhesive is nowhere near the cost of a book which falls apart. When you lose customers for a botched job, they never return. This can damage your reputation in the market.
5. Train yourselves. And keep training your people.
6. When you miss out on a job on price, do an internal evaluation to see if you could have achieved it, economically. There could be a shortfall in your system which made the job expensive. Use such instances for evaluating your costs.
On his way back to the USA, Paul Parisi had warm thoughts about India. "I am very impressed with what I saw at JAK. I am certain that the Indian book printers and binders can meet standards desirable in the world market by staying focused on the above points".
Paul Parisi is president of Acme Bookbinding, a family-owned Charlestown, Massachusetts-based trade shop and industry icon that specialises in binding books - of all shapes and sizes - as long as the customer wants a quality product. The company traces its beginnings to 1821 and the J G Roberts Company. This makes Acme Bookbinding the oldest continuously operated book
bindery in the world.
Over the years, the company has grown from a one-person basement operation to a manufacturer with a staff of 185 operating in a modern 100,000square-foot facility that has world-class systems and machinery.
Acme binds thousands of single copy hardcover books every day, many of which are for private clients. Acme's hardcover and softcover products can be Smyth sewn or adhesive bound with hotmelt, PUR or PVA. Its products include case binding and paperback binding, textbook rebinding, and library binding. Through one of its divisions, Acme Bookbinding serves printers, publishers, libraries, government agencies and other businesses throughout the United
States. Acme'snewest division, Imaging and Digital Printing, offers facsimile reproduction
of out-of-print books and digital printing of short-run books on-demand.
(http://www.acmebook.com/)
Paul Parisi was in India on a holiday with his family, visiting Rajasthan, Agra, Kerala (God's own country ; Welbound’s too) and Mumbai.
WT met him at Mumbai. Although he was on a holiday, Parisi was keen to keep tabs with business trends in India, the methods of binding / systems etc. He visited Jak Printers at Mumbai, the award winning integrated print house to observe and discuss the state of book manufacturing in India.
Paul Parisi compared notes with Khushru Patel and Aspi ---- of Jak. His passion for book binding technology was massive. He is hands-on, as far as the techniques are concerned. Though Harvard educated, he is proud to call himself a book binder, by profession. The knowledge has been painstakingly created thanks to running a modern book binding house, as well as various
visits of leading book manufacturers world over.
WT : What is the most important equipment in your bindery ?.
PP: We have Kolbus Perfect Binding Lines, Muller Martini hard cover lines, Custom-made “ On Demand case making machines” that can make seven different cases per minute - every case being of a different size, etc, the list goes on. But the most important tool in our bindery does not occupy any floor space. It is our software custom made to oversee the complex operations.
We have 5000 jobs at any given point of time. More than 3000 unique books are delivered in a day. With such a huge variety it's very easy for things to go wrong - unless you have a strong system and a solid software.
WT : In India, its often said, that by the time the job comes to the binder, and the deliveries are required 'as of yesterday'. What is the scenario in USA?
PP: The very same. Fast deliveries are order of the day. This is a world phenomena. I think, trade binderies will have to face the challenge. There have to be systems which support quick turnaround of jobs. That's our specialty. Also, one needs to be careful. We do what we can do to avoid the temptation to break a job and do "need or urgency based supply", (like supplying 100 books out of the thousand book order - and then resetting the job for the remaining number). Instead, we try to run the entire job at one time. Set-up times are very expensive. Most of us do not calculate this in our cost estimate.
WT: What advise can you give to a book binding house, in an emerging market like
India?
PP: There are six mantras.
1 Do not compromise on Quality. The key is quality control systems. We have never lost a customer due to quality problems. It's the most critical aspect of service. When you control your bindery, you control your destiny!
2 Safety should be given paramount importance as well. It has the highest priority in our factory.
3. It's better to invest in new machines, as you will have less spoilage. You will realise that you will need just one "new machine" to take the place of 2-3 old machines. Typically in cases like folding machines, the folding roller pressure, movement of paper etc are important to ensure that good quality printed sheets do not get damaged. This is decided by the quality of parts; and definitely one cannot expect the same from an old machine. In a modern thread sewing machine one can use thinner threads, set up a job in minutes and run at high speeds, adding value to the sewn job.
4. Quality of consumables. For example, the cost of adhesive is nowhere near the cost of a book which falls apart. When you lose customers for a botched job, they never return. This can damage your reputation in the market.
5. Train yourselves. And keep training your people.
6. When you miss out on a job on price, do an internal evaluation to see if you could have achieved it, economically. There could be a shortfall in your system which made the job expensive. Use such instances for evaluating your costs.
On his way back to the USA, Paul Parisi had warm thoughts about India. "I am very impressed with what I saw at JAK. I am certain that the Indian book printers and binders can meet standards desirable in the world market by staying focused on the above points".
Folding Machines and Methods of Folding - P Sajith
As a Folding machine supplier, I keep getting a number of questions on the various types and models of paper folding machines. I have seen that at many a times, a user picks up a model without understanding what it can not do!
The criteria followed by such buyers, in particular the “used” ones, are mainly (a) Brand and (b) Paper Size handled. A lot of other crucial factors are to be considered before zooming in on a specific model. These include (a) Type of Feeder (Pallet, Flat Pile, Vertical, Round etc. In small format machines, you also have friction and various types of suction feeders.) (b) Whether all buckle Or combination (c) Number of folds
(d) Direction of fold (left hand / right hand) (e) speed and the list goes on and on.
Most of the printers look at folding machine as just “another” type of machine used for folding sheets. But an automatic paper folding machine is a complex product with thousands of components and hundreds of variants. It has to address a variety
of problems , be it paper , print or fold related. It is the first link of a post printing chain in book production and hence needs to be treated with a lot of respect.
Modern day folding machines have extended beyond ‘simple folding’ and merge into the realm of packaging, mailing and so on. You can finish a complete booklet of 8/12/16 pages by either gluing or stitching and then trimming on-line.
We will understand some critical factors that define the specifications of a folding machine. You may kindly send us your specific questions that can be answered subsequently.
Speed : Folding machines of various capacities exist and are capable of folding sheets at much faster than by hand. Speeds are measured in meters per minute (instead of copies per hour), since the smaller the sheet size, the more copies can be folded in a given time. The capacity of a folding machine is also affected by the number of folding units it has. So if any one says that the machine has a speed of 10000 sheets per hour, ask him/her about the sheet size and the number of folds.
Folding machines are normally fitted with automatic feeders. Different thicknesses of paper stock and any alteration in the size of sheet require adjustment to both folding and feeding mechanisms. We will discuss various types of feeders at a different occasion.
We will deal with the most critical of them all first:
Methods of Folding: The methods by which sheets are folded by a machine can be classified into three.
1) Knife principle - where the knife folder accepts the long edge first. Figure 1.a shows the knife-folding principle. A vertically descending knife pushes the sheet between two contra-rotating rollers.
2) Buckle principle – where the buckle folder accepts the short edge first (this is more commonly seen). Figure 1.b shows the buckle-folding principle. The principle involves 3 rollers and a buckle plate. The first two rollers, one arranged vertically on top of the other, leads the sheet into the buckle plate till the leading edge of the sheet hits the buckle stopper. The paper bends (buckles) and sags between the rollers. This is picked up by the contra rotating rollers (placed side by side, arranged horizontally). You can have a number of buckle plates in a folding station for multiple parallel folds (eg. Accordion fold)
3) Combination - Knife-folding machines are uncommon and have largely been replaced by combination folders. The style of folding used varies from the basic right-angle folds, to the multi-stage machines employing mainly parallel styles. You can have knives after buckles and again a buckle and so on. Combination folders are specific to a set of jobs that can be done using them.
Buckle-folding machines (also knows as plate folders) are considerably faster than knife machines due to a more continuous process of operation. This is because, on a knife folder, the sheet must be halted at each folding stage before the knife descends to complete the operation, which also demands that the feeder coincides with the knife movement.
The buckle system is ideal for parallel styles of folding. One can have a multiple stage (all buckle) system, where paper is turned at right angle after each stage. Thicker sheets are not really suited to right-angle styles. Accuracy can be improved by the use of pre-creasing units fitted on the folding machines. Beyond certain thickness, one will need a knife unit to accomplish the fold.
Perforation should be made before the fold wherever possible except when folding lightweight papers which may tear while perforating. As the perforation is always made during the fold preceding the fold which will be made along it, the first fold cannot be perforated. Buckle folders can also slit a sheet after the first fold, the two sheets thus created following each other through and ending up as separate folded sections.
Combination-folding machines employ both buckle and knife systems and, though not as fast as all-buckle machines, are very versatile. They can handle both parallel and right-angle styles and are ideally suitable for book signatures. They are effective for folding signatures with sections having both parallel and right-angled styles. The first stage is normally buckle and the later ones knife-folds, thereby maintaining accuracy despite the gradual increase in the bulk of the work.
The criteria followed by such buyers, in particular the “used” ones, are mainly (a) Brand and (b) Paper Size handled. A lot of other crucial factors are to be considered before zooming in on a specific model. These include (a) Type of Feeder (Pallet, Flat Pile, Vertical, Round etc. In small format machines, you also have friction and various types of suction feeders.) (b) Whether all buckle Or combination (c) Number of folds
(d) Direction of fold (left hand / right hand) (e) speed and the list goes on and on.
Most of the printers look at folding machine as just “another” type of machine used for folding sheets. But an automatic paper folding machine is a complex product with thousands of components and hundreds of variants. It has to address a variety
of problems , be it paper , print or fold related. It is the first link of a post printing chain in book production and hence needs to be treated with a lot of respect.
Modern day folding machines have extended beyond ‘simple folding’ and merge into the realm of packaging, mailing and so on. You can finish a complete booklet of 8/12/16 pages by either gluing or stitching and then trimming on-line.
We will understand some critical factors that define the specifications of a folding machine. You may kindly send us your specific questions that can be answered subsequently.
Speed : Folding machines of various capacities exist and are capable of folding sheets at much faster than by hand. Speeds are measured in meters per minute (instead of copies per hour), since the smaller the sheet size, the more copies can be folded in a given time. The capacity of a folding machine is also affected by the number of folding units it has. So if any one says that the machine has a speed of 10000 sheets per hour, ask him/her about the sheet size and the number of folds.
Folding machines are normally fitted with automatic feeders. Different thicknesses of paper stock and any alteration in the size of sheet require adjustment to both folding and feeding mechanisms. We will discuss various types of feeders at a different occasion.
We will deal with the most critical of them all first:
Methods of Folding: The methods by which sheets are folded by a machine can be classified into three.
1) Knife principle - where the knife folder accepts the long edge first. Figure 1.a shows the knife-folding principle. A vertically descending knife pushes the sheet between two contra-rotating rollers.
2) Buckle principle – where the buckle folder accepts the short edge first (this is more commonly seen). Figure 1.b shows the buckle-folding principle. The principle involves 3 rollers and a buckle plate. The first two rollers, one arranged vertically on top of the other, leads the sheet into the buckle plate till the leading edge of the sheet hits the buckle stopper. The paper bends (buckles) and sags between the rollers. This is picked up by the contra rotating rollers (placed side by side, arranged horizontally). You can have a number of buckle plates in a folding station for multiple parallel folds (eg. Accordion fold)
3) Combination - Knife-folding machines are uncommon and have largely been replaced by combination folders. The style of folding used varies from the basic right-angle folds, to the multi-stage machines employing mainly parallel styles. You can have knives after buckles and again a buckle and so on. Combination folders are specific to a set of jobs that can be done using them.
Buckle-folding machines (also knows as plate folders) are considerably faster than knife machines due to a more continuous process of operation. This is because, on a knife folder, the sheet must be halted at each folding stage before the knife descends to complete the operation, which also demands that the feeder coincides with the knife movement.
The buckle system is ideal for parallel styles of folding. One can have a multiple stage (all buckle) system, where paper is turned at right angle after each stage. Thicker sheets are not really suited to right-angle styles. Accuracy can be improved by the use of pre-creasing units fitted on the folding machines. Beyond certain thickness, one will need a knife unit to accomplish the fold.
Perforation should be made before the fold wherever possible except when folding lightweight papers which may tear while perforating. As the perforation is always made during the fold preceding the fold which will be made along it, the first fold cannot be perforated. Buckle folders can also slit a sheet after the first fold, the two sheets thus created following each other through and ending up as separate folded sections.
Combination-folding machines employ both buckle and knife systems and, though not as fast as all-buckle machines, are very versatile. They can handle both parallel and right-angle styles and are ideally suitable for book signatures. They are effective for folding signatures with sections having both parallel and right-angled styles. The first stage is normally buckle and the later ones knife-folds, thereby maintaining accuracy despite the gradual increase in the bulk of the work.
A Costly Mistake - Tony Clark
A Costly Mistake
(Tony Clark)
Some months ago a Director of a Bindery sent me a book that the Publisher had rejected due to pages falling out. He asked me to strength test the book and refute the claim which if proven would cost him some £50,000 to re-print.
The tests showed that the centre pages were very weak and the best result was 2N/cm. After taking off the cover of the spine it could be seen that the cover adhesion was less than 50% and there were large holes in the glue film.
When I telephoned the owner of the Bindery he said that was impossible as the binding machine was computer set. I informed him that the computer cannot see holes in the glue film, (neither can the operators) unless they remove the cover and cut down the spine for a good inspection.
Every time the machine is changed for different sizes or after the spine cutter has been sharpened the books must be checked. Changing the adhesive from one make to another can mean different settings due to a viscosity change and even the ambient temperature can make a difference.
What about moving from 8 page sections to 96 page units or from perfect binding to burst/slotted binding? (See the box )
That of course is the one change-over when the binding machine has to have most of its settings altered.
When setting up a machine to perform the burst-binding operation, firstly, set the infeed table so that the sections do not touch the spine cutter. The bookblock then has to be moved over the glue rollers to make sure that the spine clears the rollers otherwise the folds pressed on to the first roller would close the burst or slot preventing adhesive penetration.
With burst-binding the adhesive is only pushed into the centre sections at the cover- application station. The adhesive should be still movable as it presses the cover or the lining materials upwards and the side nips.
One other point, when the slots are being cut and the last fold has been made do inspect the sections because the fold generally is not perfectly down the centre of the fold and the slots are sometimes to one side or the other.
Therefore to get adhesive into the first or last section a wire needs to be placed on the first roller to create a bow wave of adhesive to help the application into that off-set fold.
When the first burst-bound books have cooled open the first and last sections in the middle to make sure that you have got good adhesive penetration.
It is generally the first and last sections that fail in slotted/burst binding. If ever the centre sections fail it is always due to lack of spine upward pressure for when the adhesive is pushed into the slots the side nip moves it just that little bit more.
Now that you have completed the burst bound job the whole machine has to be re-set for Perfect binding. Measure the amount of fold cut off and the gap between the first glue roller and the cut spine before re-setting the height of the cover station.
So, to go back to the faulty book sent to me .If the operator had done the standard test of removing the cover or putting the book on a simple page pull tester the Bookbinding Company in question would not have had to pay out for a reprint and bind.
All operators should have a magnifying glass and a knife to check the glue film. ( If you use too much glue you are throwing away money and too little and the books will fall to bits or will not have the cold/heat resistance). All larger Binderies should have a page strength tester; these units once purchased will last a life time of service as there are no parts to wear out and the digital readout runs from the mains or a re-chargeable battery. The cost of reprinting and binding may be off set with insurance ( but these costs keep rising ) and it is the loss of reputation that cannot be brought back. Always test books at the beginning of the run and at regular intervals throughout. Tony Clark 28 5 07
Burst / slotted binding
Burst, slotted or perforated binding is a system whereby a slit or a slot is punched into the paper prior to the last fold. The length of this slit will be governed by several factors:
1) The type of adhesive used.
2) The speed of the binding machine.
3) How clean a cut can be made by the folding machine or web press.
Burst / slotted binding has been extremely successful with emulsion adhesives. This is because after the book block is bound, emulsion will carry on moving until completely dry. Other adhesive systems suitable for burst or slotted binding include the Twinflex or emulsion – hotmelt system, provided that after the emulsion has been forced into the slot, the surface adhesive is scraped off and brushed out and sufficient heat is used to dry all the emulsion before the hotmelt is applied to the spine. Two-shot hotmelt systems are also in use with burst binding, using a primer hotmelt of very low-viscosity and long open-time and a higher-viscosity hotmelt that helps to force the primer product well into the slot.
(Tony Clark)
Some months ago a Director of a Bindery sent me a book that the Publisher had rejected due to pages falling out. He asked me to strength test the book and refute the claim which if proven would cost him some £50,000 to re-print.
The tests showed that the centre pages were very weak and the best result was 2N/cm. After taking off the cover of the spine it could be seen that the cover adhesion was less than 50% and there were large holes in the glue film.
When I telephoned the owner of the Bindery he said that was impossible as the binding machine was computer set. I informed him that the computer cannot see holes in the glue film, (neither can the operators) unless they remove the cover and cut down the spine for a good inspection.
Every time the machine is changed for different sizes or after the spine cutter has been sharpened the books must be checked. Changing the adhesive from one make to another can mean different settings due to a viscosity change and even the ambient temperature can make a difference.
What about moving from 8 page sections to 96 page units or from perfect binding to burst/slotted binding? (See the box )
That of course is the one change-over when the binding machine has to have most of its settings altered.
When setting up a machine to perform the burst-binding operation, firstly, set the infeed table so that the sections do not touch the spine cutter. The bookblock then has to be moved over the glue rollers to make sure that the spine clears the rollers otherwise the folds pressed on to the first roller would close the burst or slot preventing adhesive penetration.
With burst-binding the adhesive is only pushed into the centre sections at the cover- application station. The adhesive should be still movable as it presses the cover or the lining materials upwards and the side nips.
One other point, when the slots are being cut and the last fold has been made do inspect the sections because the fold generally is not perfectly down the centre of the fold and the slots are sometimes to one side or the other.
Therefore to get adhesive into the first or last section a wire needs to be placed on the first roller to create a bow wave of adhesive to help the application into that off-set fold.
When the first burst-bound books have cooled open the first and last sections in the middle to make sure that you have got good adhesive penetration.
It is generally the first and last sections that fail in slotted/burst binding. If ever the centre sections fail it is always due to lack of spine upward pressure for when the adhesive is pushed into the slots the side nip moves it just that little bit more.
Now that you have completed the burst bound job the whole machine has to be re-set for Perfect binding. Measure the amount of fold cut off and the gap between the first glue roller and the cut spine before re-setting the height of the cover station.
So, to go back to the faulty book sent to me .If the operator had done the standard test of removing the cover or putting the book on a simple page pull tester the Bookbinding Company in question would not have had to pay out for a reprint and bind.
All operators should have a magnifying glass and a knife to check the glue film. ( If you use too much glue you are throwing away money and too little and the books will fall to bits or will not have the cold/heat resistance). All larger Binderies should have a page strength tester; these units once purchased will last a life time of service as there are no parts to wear out and the digital readout runs from the mains or a re-chargeable battery. The cost of reprinting and binding may be off set with insurance ( but these costs keep rising ) and it is the loss of reputation that cannot be brought back. Always test books at the beginning of the run and at regular intervals throughout. Tony Clark 28 5 07
Burst / slotted binding
Burst, slotted or perforated binding is a system whereby a slit or a slot is punched into the paper prior to the last fold. The length of this slit will be governed by several factors:
1) The type of adhesive used.
2) The speed of the binding machine.
3) How clean a cut can be made by the folding machine or web press.
Burst / slotted binding has been extremely successful with emulsion adhesives. This is because after the book block is bound, emulsion will carry on moving until completely dry. Other adhesive systems suitable for burst or slotted binding include the Twinflex or emulsion – hotmelt system, provided that after the emulsion has been forced into the slot, the surface adhesive is scraped off and brushed out and sufficient heat is used to dry all the emulsion before the hotmelt is applied to the spine. Two-shot hotmelt systems are also in use with burst binding, using a primer hotmelt of very low-viscosity and long open-time and a higher-viscosity hotmelt that helps to force the primer product well into the slot.
Wednesday, November 22, 2006
Tony Talks -- A J Clark
Trouble Shooting Guide on Paper Problems for the Bookbinder
I was told that this issue of WT will focus on substrates – paper , board etc that get bonded together.
The paper upon which the book is produced is usually chosen by the publisher or book designer. The criteria is that it should be ideal for the printing equipment to be used and the print quality required. Unfortunately the best papers for printing are almost invariably the least favorable for adhesive binding.
The best paper to bind is fibrous, uncoated and fairly bulky – eg Newsprint, Antique Wove types. Short fibre - coated papers (such as art paper) do not bind, easily. This type of paper is difficult to bind with single roller gluing systems.
Testing for Paper Grain : There have been many discussions on the subject in the past, but just to recap on this as well as to understand more – The paper you intend to bind contains a grain, which is created by the flow of the pulp stock as it is suspended on the endless wire belt of the paper mill (machine)
Fig (2.1) Grain Direction
1. Pinch the paper between the fingernails
2. Draw lightly down the edge
3. There will be no stretch with grain but stretch mark across the grain
Fig 2.1 (cont)
Long Grain - This is cut lengthwise from the paper web so that the direction of grain runs parallel to longer side
Short Grain – is cut crosswise from the paper web so that the grain runs across the shorter side.
The best bind is obtained when the grain of paper runs parallel to the spine of the book. Cross grained paper can be only bound (as a last resort) provided the paper is fibrous and not too heavy (low gsm)
Given below are a few typical issues related to paper and the solutions.
Cocking or wavy edges - Over-dried paper will steadily increase its relative humidity, thus the problem will grow. Keep drying temperatures as low as possible; remoisten on the press.
Cracking at the fold - Over dried with intense heat, makes the coating medium brittle. Remoisten where possible or use a water line.
Fibre lift - Mechanical fibres that contain lignin expand under heat; this can give glossy papers a rougher surface. Keep drying temperatures low. Ask the buyer to choose wood-free paper.
Poor page strength - Good results one week, poor results the next and yet bound on the same machine, same adhesive and operator. Intense drying makes the fibres brittle, i.e. LWC paper is 50 per cent mechanical pulp and 50 per cent wood free. Brittleness in the ground wood can reduce the page flex and pull strength by half.
Stepping after trimming Over-dried and mixed paper stocks. Growth will vary in speed and amount due to the relevant humidity. Keep drying temperatures to a minimum, re-moisten on the press, and do not use mixed papers.
Wrinkles on Spine after the trimming operation –
Perfect Binding, if not perfect in all aspects is to deliver perfectly smooth spine. Wrinkles on book spine are caused due to many reasons, including the cover stock.
Spin crease - Spongy spine. Increase nip pressure on the binding machine. Check guillotine clamp pressure. Investigate the grinding angle of blade. Test for damp cover board due to aqueous links or varnishes. Monitor board de-lamination and test other boards on the same work.
I was told that this issue of WT will focus on substrates – paper , board etc that get bonded together.
The paper upon which the book is produced is usually chosen by the publisher or book designer. The criteria is that it should be ideal for the printing equipment to be used and the print quality required. Unfortunately the best papers for printing are almost invariably the least favorable for adhesive binding.
The best paper to bind is fibrous, uncoated and fairly bulky – eg Newsprint, Antique Wove types. Short fibre - coated papers (such as art paper) do not bind, easily. This type of paper is difficult to bind with single roller gluing systems.
Testing for Paper Grain : There have been many discussions on the subject in the past, but just to recap on this as well as to understand more – The paper you intend to bind contains a grain, which is created by the flow of the pulp stock as it is suspended on the endless wire belt of the paper mill (machine)
Fig (2.1) Grain Direction
1. Pinch the paper between the fingernails
2. Draw lightly down the edge
3. There will be no stretch with grain but stretch mark across the grain
Fig 2.1 (cont)
Long Grain - This is cut lengthwise from the paper web so that the direction of grain runs parallel to longer side
Short Grain – is cut crosswise from the paper web so that the grain runs across the shorter side.
The best bind is obtained when the grain of paper runs parallel to the spine of the book. Cross grained paper can be only bound (as a last resort) provided the paper is fibrous and not too heavy (low gsm)
Given below are a few typical issues related to paper and the solutions.
Cocking or wavy edges - Over-dried paper will steadily increase its relative humidity, thus the problem will grow. Keep drying temperatures as low as possible; remoisten on the press.
Cracking at the fold - Over dried with intense heat, makes the coating medium brittle. Remoisten where possible or use a water line.
Fibre lift - Mechanical fibres that contain lignin expand under heat; this can give glossy papers a rougher surface. Keep drying temperatures low. Ask the buyer to choose wood-free paper.
Poor page strength - Good results one week, poor results the next and yet bound on the same machine, same adhesive and operator. Intense drying makes the fibres brittle, i.e. LWC paper is 50 per cent mechanical pulp and 50 per cent wood free. Brittleness in the ground wood can reduce the page flex and pull strength by half.
Stepping after trimming Over-dried and mixed paper stocks. Growth will vary in speed and amount due to the relevant humidity. Keep drying temperatures to a minimum, re-moisten on the press, and do not use mixed papers.
Wrinkles on Spine after the trimming operation –
Perfect Binding, if not perfect in all aspects is to deliver perfectly smooth spine. Wrinkles on book spine are caused due to many reasons, including the cover stock.
Spin crease - Spongy spine. Increase nip pressure on the binding machine. Check guillotine clamp pressure. Investigate the grinding angle of blade. Test for damp cover board due to aqueous links or varnishes. Monitor board de-lamination and test other boards on the same work.
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