Book article

Abstract

An improved book article has a book body attached to a case at the hinge by a bonding agent having a short period of adhesiveness following exposure to indirectly applied energy. The bonding agent is located at the hinge area of the book.

Parent Case Text

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional application of copending application, Ser. No. 74,271, filed Sept. 22, 1970, now U.S. Pat. No. 3,730,806.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is directed to an improved book article.

2. Description of the Prior Art

The ordinary hard bound book consists of two main parts, the case and the body. The case comprises the front and the back covers connected by the spine. The covers are hinged along either edge of the spine. An indentation or groove in the case at the spine edges allows the cover to be opened and closed easily.

The body of the book is comprised of a plurality of paper sheets termed leaves. The leaves are sewn together along their center folds in groups of 16 or more to form the sections or signatures of the book. The signatures are assembled by additional sewing, binding to tapes or cords, or the like, to form the body of the book. At the front and back of the body are affixed heavy folded pages, termed the end papers, which facilitate the attachment of the body to the case.

To effect this attachment, the center of a piece of fabric, termed crash, is glued to the centerfolds of the body signatures. The ends of the crash extend along the outside of the end papers on either side of the body. The body is then inserted in the case so that the folds in the end papers are adjacent the spine of the case. Paste is applied to both sides of the crash and to the sides of the front and back end papers adjacent the insides of the covers of the case. The end papers are pasted to the inside of the covers, enclosing the crash. The case and body are then placed in a press to form the groove at either edge of the case spine. When the attachment process, termed casing in, is complete, the body is bound to the case at the hinge so that the covers and leaves are movable with respect to each other.

From the standpoint of durability and utility of the completed book, the hinge forms a most critical portion thereof. The hinge must have sufficient flexibility to permit the covers to open and close easily and to lie flat when the book is in use. On the other hand, the hinge must have sufficient strength to retain the body in the case under conditions of normal wear and tear throughout the useful life of the book.

The creation of satisfactory book hinges having the desired qualities of flexibility and strength makes severe demands on the bonding materials and techniques utilized in the book article and becomes particularly critical with the high processing speeds employed in modern bookbinding methods.

In a book bound with conventional bookbinding paste of the starch or animal variety, continuous application of pressure to the hinge area of the bound book is desirable until the paste is dry or at least until it has set in order to form a satisfactory hinge. The application of pressure is necessary, in part, to overcome the natural springiness of the materials which tends to separate the hinge. Such conditions have not been previously obtainable at the processing speeds employed in the commercially and economically feasible book binding processes, with the result that pressure is prematurely removed from the book causing faulty bonding in the hinge and an unsatisfactory book article.

One expedient commonly employed to improve the quality of bound book hinges is to carefully stack the books after binding so that no strain is on the hinge area. The books are left in this condition for a period of time, typically 24 hours, before shipping. Pressure is thus applied to the books as the paste dries. While this technique is simple and feasible to some extent, it leaves much to be desired in terms of uniformity and control of pressure. The extra handling and storage of the stacked books increase the cost of the books.

A second expedient has been to accelerate the drying of the paste. For this purpose, the press used to form the hinge is equipped with heated press platens so that heat, as well as pressure, is applied to the book undergoing binding. However, the heat of the platens must pass through the cover in order to reach the paste on the inside thereof. Typical cover materials include multi-layer cardboard and buckram, both of which tend to be good thermal insulators. Thus, considerable time is required for this directly applied heat to pass through the case to the paste area and the desired bonding result is not achieved without an unwanted reduction in the speed of the binding process.

While higher platen temperatures may be utilized to increase the rate at which heat passes to the paste area, the point is quickly reached at which scorching and degradation of the case and body materials becomes likely. Thus, the use of heated press platens has not achieved the desired result of increasing binding speed without undue loss of hinge quality.

Another drawback of prior art binding processes is that the paste when it reaches the point at which pressure is applied in the casing-in line, may have reached different degrees of drying. This may be due to variations in the viscosity of the paste from time to time even from the same batch, or to differences in the paste from batch to batch, or to differences in the climate conditions in the binding room, or to changes in the operating speed of the machine, or for a number of other reasons. This results in variations in the bond at the hinge joint obtained during casing-in.

It is thus characteristic of prior art books that the strength of the hinge joint varies widely, even though they are manufactured in one batch sequentially one after the other.

Yet another expedient which has been used is to employ hot melts, i.e., substances which are applied to the book parts in the molten form and which subsequently solidify to affix the body to the case. However, such substances are difficult to handle and apply, are low in strength, and are expensive. Further, commercially feasible hot melts have a fairly long solidification period, for example, seven seconds, so that only modest increases in processing speed are obtainable.

SUMMARY OF THE PRESENT INVENTION

It is therefore the object of the present invention to provide an improved bound book featuring an enhancement in the quality and uniformity of quality of the hinge joint.

It is a further object of the present invention to provide an improved book article having a case and body which are formed in the normal manner and which permits, insofar as is possible, use of conventional book binding techniques, thereby permitting the use of existing book binding equipment.

It is another object of the present invention to provide an improved book article in which the conventional book binding techniques are reinforced at certain critical areas.

In summary, the present invention provides an improved book article incorporating a bonding agent having a thermally induced short period of adhesiveness on the body or case adjacent the hinge area. The short adhesive period of the bonding agent is induced by exposure of the agent to a selected form of indirectly applied energy. A suitable bonding agent is typically formed by dispersing, in a thermoplastic carrier, a susceptor material heatable by indirectly applied energy. The bonding agent may be applied directly to the end papers, crash, and covers of the book in the conventional manner or may be applied as a separate material film interposed between the above identified elements. The bonding agent may be used in conjunction with conventional pastes to reinforce the hinges of the book.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a perspective view of a typical hard bound book, a portion of the hinge area of the book being broken away to reveal the construction thereof

FIG. 2 is a cross sectional view showing, in detail, the hinge area of the improved book of the present invention.

FIG. 3 is a cross sectional view similar to FIG. 2, showing a step in the process of manufacture of the book of the present invention.

FIG. 4 is a cross sectional view similar to FIG. 2, showing a modification of the improved book of the present invention.

FIG. 5 is a cross sectional view similar to FIG. 3, showing the use of a different type of indirectly applied energy in manufacturing the book of the present invention.

FIGS. 2 through 5 show the book hinge in a somewhat exaggerated form to facilitate an understanding of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Turning now to FIG. 1, there is shown therein an assembled hard bound book 10 comprised of case 12 and body 14. Case 12 includes front cover 16a and back cover 16b, each of which is formed of board 18 covered with buckram cloth 20. Buckram cloth 20 connects the boards at spine 22. A groove 24 formed in the buckram at either edge of the spine permits the covers to hinge on the spine.

The body 14 of the book 10 is formed of a plurality of leaves 26 folded on a center fold and sewn together to form signatures 28 which are sewn on cords 29 to form body 14. End papers 30 are affixed to the front and back of the body so as to abut the inner surfaces of front and back cover boards 18.

The crash 32 is cemented to the center folds of the assembled signatures across cords 29 and extends along the exterior surface of the end papers between the cover boards and the end papers. If desired, the portion of crash 32 adjacent the spine of the book may be covered with kraft paper 34.

In the conventional prior art book article, the crash is pasted to the end papers and to the insides of the cover boards at the hinge in the presence of such pressures and/or heat as is obtainable to attach the body to the case and form the assembled hard bound book.

To overcome the shortcomings of the prior art, as noted above, the present invention contemplates the use of a bonding agent having a short period of adhesiveness responsive to exposure to a selected form of indirectly applied energy. The exposure typically results in a temperature increase and the bonding agent may be thermoplastic in nature. In the alternative, the bonding agent may be thermosetting, such as an epoxy compound having a cure rate proportional to temperature. A bonding agent having a short period of adhesiveness is often said to have a short "open time".

By the term "indirectly applied energy" it is meant that the energy responsible for the temperature increase is applied through the medium of a radiant field, rather than by direct application of, for example, a heated platen. Typically, the radiant fields are electric or magnetic fields.

A bonding agent having the necessary properties for successful practice of the present invention may be formed by selecting a thermoplastic or thermosetting carrier and dispersing therein a material susceptable to heating by the indirectly applied energy. The material is preferably in particulate form and is incorporated in the carrier in quantities sufficient to produce the desired heating action. This is typically 10 to 50% by weight with respect to the carrier. Such material, termed herein a susceptor, may be responsive to the indirect application of energy in the form of an alternating magnetic field, in which case the susceptor could consist of material heatable by induction heating, such as fine particles of iron oxide, preferrably gamma (.alpha.) Fe.sub.2 O.sub.3. Metal particles or ferrite particles may also be used. The material may be responsive to an alternating electric field in which case a dielectrically heatable substance such as polyvinyl chloride may be used.

The carrier may, under normal conditions, be a fluid substance, typically a liquid, having the susceptor suspended therein, or the carrier may be solid substance, such as a film or layer, having the susceptor dispersed therein. In the case of a liquid carrier, the carrier should be dryable at a rate commensurate with the speed of the casing-in process. A typical carrier of the thermoplastic type which has been found useful in the process of the present invention is the water emulsion of ethylene vinyl acetate sold under the trade designation Aircoflex 400 by Air Reduction Co., New York, N.Y. The period of adhesiveness or open time of such a carrier upon termination of the application of heat is on the order of one second.

In some cases, for example, where an alternating electric field is being used, it may be possible to select a dielectrically heatable substance which itself may act as the bonding agent.

The bonding agent, formed as described above, is applied to the book portions to commence the casing operating. As shown in FIG. 2, the bonding agent, identified by numeral 36, may contact both sides of crash 34 adjacent hinge 24 as well as the inside of boards 18 of covers 16a and 16b and the outsides of end papers 30. In cases in which bonding agent 36 is in fluid form, it may be applied to a desired combination of the above mentioned surfaces. It has been found preferable, from the standpoint of reducing unwanted smearing, adhesion, and the like, to allow bonding agent 36 to assume the dry state before further processing of book 10.

When bonding agent 36 is in solid form, it may be applied to the hinge area, either before or after assembly of the case and body, as hereinafter described.

Body 14 is inserted in case 12 with that portion of crash 34 located across the center folds of signatures 28 abutting spine 22. This locates the portions of crash 32, or end papers 30, to which bonding agent 36 has been applied at hinge 24. In the case where bonding agent 36 has been applied to case 12, this places crash 32 and end papers 30 adjacent the treated portions of case 12.

The bonding agent is then exposed to the indirectly applied energy as by inserting hinge 24 into a radiant field. In the instance in which the susceptor is inductively heatable, an alternating magnetic field may be established by coils 42, shown in cross section in FIG. 3 energized by the current of alternating source 44. Coils 42 may be cooled by coolant circulated in passages 46, to prevent scorching or degradation of buckram 20 of boards 18.

Upon insertion in the field of coils 42, the susceptor of the bonding agent increases in temperature causing the agent carrier to enter the adhesive state and commence the bonding process.

During the time bonding agent 36 is in the adhesive state, i.e., during the open time of the bonding agent, pressure is applied to book 10 in the area of hinge 24. While separate pressure applying means may be used, it is advantageous to utilize the pressure applying means, platen 48, as the support for coils 42, as shown in FIG. 3. Pressure is applied in the direction of the arrows in FIG. 3.

The pressure applied by platen 48 continues until the termination of the period of adhesiveness of bonding agent 36 or until bonding agent 36 is set, and boards 18, crash 32, and end papers 30 are firmly bonded at hinge 24. Removal of book 10 from the field of coils 42, or the turn off of alternating current source 44 initiates the termination of the period of adhesiveness in a thermoplastic carrier. Pressure may be applied prior to the termination of the heating of the susceptor, if desired. When bonding agent 36 has set, the pressure may be removed and the casing in of book 10 is complete. Because pressure is applied during the entire time bonding agent 36 is setting, a highly satisfactory hinge joint is obtained through the firm adhesion and its continuity throughout the hinge area. There is also considerably less variation in the quality of the hinge joint than has heretofore been experienced.

In the case in which bonding agent is subjected to dielectric heating, case 12 and body 14 may be placed in an electric field created by electrodes 50 energized by alternating current voltage source 52. Platens 48 may be incorporated in electrodes 50 as shown in FIG. 5. The remaining steps of the process proceed as described in connection with FIGS. 2 and 3.

The present invention also contemplates the reinforcement of the hinges of books cased in in the normal manner. Bonding agent 36 is placed in hinge 24 at the points of joinder or at points of excessive stress, flexure, and wear, as shown in FIG. 4, adjacent the conventional paste 54. Bonding agent 36 is treated in the manner described above to insure that adequate bonding occurs at the aforesaid points, thereby to improve the strength and durability of hinges 24. With the critical points of the hinge joint bonded by bonding agent 36, the conventional paste may dry in the ordinary manner and without pressure without affecting the quality of the hinge.

Various modes of carrying out the invention are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

Claims

We claim:

1. A bound book having a pair of covers separated by a spine and embracing a body of leaves bound along one edge, said body and covers having abuttable surfaces suitable for joinder at a hinge area of the book, said book having a composite hinge joint comprising abutting surfaces of the covers located adjacent the spine and abutting surfaces of said body of leaves adjacent said bound edge, said hinge joint having a first portion joined by conventional book binding paste and a second portion which is subjected to stress during use of the book, said second portion being joined by a solidified bonding agent comprised of a thermoplastic adhesive carrier containing dispersed particulate gamma Fe.sub.2 O.sub.3.

2. The book according to claim 1 wherein the body of leaves has end papers, adjacent the bound edge and wherein said hinge joint is formed, in part, by the joinder of said end papers to said covers by said bonding agent at said second portion.

3. The book according to claim 2 wherein said body of leaves includes crash across the bound edge and the adjacent exterior of the end papers, said hinge joint being formed by the interposition of the crash between the covers and the end papers and the joinder of said crash, covers, and end papers by said conventional paste at said first portion and said bonding agent at said second portion.

4. The book according to claim 1 wherein said bonding agent is further defined as containing 10 to 50% by weight of dispersed particulate gamma Fe.sub.2 O.sub.3 with respect to said carrier.