BOOKBINDING AND ITS PRODUCTS

Abstract: In a method of bookbinding arranged ends of superposed sheets 2 are bonded by friction welding to a thermoplastic inner face of a spine of a cover 1 by means of friction heat generated between the thermoplastic inner face of the spine and the arranged ends of the sheets 2. The sheets 2 may be of a thermoplastic resin. A thermoplastic film may be interposed between the inner face of the spine and the arranged ends of the sheets 2, said thermoplastic film optionally being united with flap sheets which are superposed on either both sides or one side of the sheets 2 and, optionally, being united with one or more supporting sheets interposed between the sheets 2.

Description: The present invention relates to bookbinding and its products, such as files, wherein a plurality of sheets which are superposed on each other are bonded to an inner face of a spine of a cover at their arranged ends. In the prior art bookbinding was generally achieved by adhering the arranged ends of the sheets to the inner face of a cover using an adhesive. For example, British Patent Specification No. 1,510,122 discloses a method in which the edges of a stack of sheets are placed in contact with a tape that comprises a web of heatactivatible adhesive and a backing or reinforcing substrate which is electrically conductive, an electric current then being passed therethrough so as to activate the adhesive and bond the sheets and tape together. A thermoplastic hot melt adhesive is preferred. It is one of the problems of the prior art to need an adhesive and another problem is that a cheap adhesive having an excellent adhesive strength is hardly obtained when the bound sheets and the cover are made with a thermoplastic resin such as polypropylene. In one attempt to solve the above-mentioned problems, in one method of bookbinding, the arranged ends of sheets made with a thermoplastic resin are bonded to the inner face of the spine made with the same thermoplastic resin by holding the arranged ends of the superposed sheets by a clamping means with a slight projection of the ends and pressing the inner face of the spine onto the ends using a high frequency vibrator such as an ultrasonic horn from the rear side of the spine of the cover and thereby welding the thermoplastic resins of the ends of the sheets and the inner face of the spine. Said welding bookbinding using a high frequency vibrator has the defects that the welding time is comparatively long and thereby power consumption becomes great. Furthermore, the outer face of the spine is likely to melt or suffer from damage or breakage due to a successive pressing of a high frequency vibrator. The Applicants have now discovered that improved results are obtained if relative reciprocatory motion is caused in a direction parallel to the contact plane between the cover and the sheets. The present invention accordingly provides a method of binding sheets to a face of a cover, the material constituting the said face being thermoplastic, comprising superposing the sheets to form a stack, a region of thermoplastic material being provided along an edge of the stack, pressing an edge of the stack against the said face and causing relative motion of the cover and the edge of the stack so that the said edge bonds to the cover by means of friction heat generated in the said region and in the face by the motion, wherein the relative reciprocatory motion of the cover and the edge of the stack is caused in a direction parallel to the contact plane therebetween to generate the said friction heat. Bookbinding accomplished in accordance with the present invention enables damage to the outer face of the spine of the cover to be avoided and is of less energy consumption and a bookbinding product obtained shows a high quality appearance. Preferably, a micro vibration is applied to at least either the cover or the sheets in parallel with the contact plane to cause the said reciprocatory motion. Micro vibration as used herein means a vibration having an amplitude of from 0.5 to 2.00 mm and a frequency of from 150 to 300 cps (Hz). In the method, the region of thermoplastic material may comprise the sheet ends, which ends may be made of thermoplastic material. In this case, the method may comprise pressing the ends of the superposed sheets made with a thermoplastic resin onto the inner face of the spine of the cover made with a thermoplastic resin, applying a micro vibration to at least either the cover or the sheets in parallel with a contact plane wherein the ends of the sheets and the inner face of the spine are pressed to each other and thereby bonding the ends of the sheets to the inner face of the spine of the cover by means of friction welding. In this way, a bookbinding product, for example a file, may be obtained by bonding the ends of the superposed sheets made with a thermoplastic resin to the inner face of the spine of the cover made with a thermoplastic resin by means of friction welding between the spine and the ends of the sheets which are subjected to a mutual reciprocating motion while pressing each other. The above bookbinding method is only applicable for combining the ends of the sheets and the spine of the cover when both the ends and the spine are made with a thermoplastic resin; sheets made with other materials such as papers are not susceptible of the same bonding process. The present invention also provides an improved bookbinding method, and products thereof, wherein not only superposed sheets having ends made of a thermoplastic resin can be used, but also superposed sheets of other materials, for example, papers, can be bonded by welding to the inner face of the spine of the cover made with a thermoplastic resin in a short time and with little power consumption and also without suffering from damage or breakage at the outer face of the spine. According to the present invention, this may be achieved by providing a region of thermoplastic material comprising a film which is positioned between the edge of the stack and the inner face of the spine. The method may comprise pressing arranged ends of superposed sheets to a thermoplastic inner face of a spine of a cover, interposing a thermoplastic film therebetween, applying a micro vibration to at least either the cover or the sheets in parallel with a contact plane wherein the ends of the sheets and the inner face of the spine are pressed to each other to melt both the thermoplastic resin of the inner face of the spine and the thermoplastic film by a friction heat generated by said micro reciprocating motion and thereby bonding the ends of the sheets to the inner face of the spine of the cover. The thermoplastic films may have flap sheets which are superposed on either one side or both sides of the sheets. Said thermoplastic films may also have one or more supporting sheets to be interposed between the sheets. Employing a thermoplastic film to be interposed between the ends of the bound sheets and the inner face of the spine of the cover enables desired bookbinding for the bound sheets made with not only thermoplastic resins but also other materials like papers. The present invention also provides a bookbinding product obtainable by the above-mentioned method, which product comprises a cover having an inner face of a spine made with a thermoplastic resin and superposed bound sheets whose arranged ends are bonded by friction welding to the inner face of the spine of the cover, a thermoplastic film being positioned between the inner face of the spine and the arranged ends of the superposed sheets, friction welding of the end of the sheets to the inner face of the spine being completed by means of friction heat which is generated by a mutual reciprocating motion of the inner face of the spine and the ends of the sheets. The present invention will be further described, by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a schematic side view of an apparatus for accomplishing bookbinding in accordance with one embodiment of the present invention; Fig. 2 is a sectional view taken along II-II line shown in Fig. 1; Fig. 3 is a side view of a bookbinding product obtained by using the apparatus shown in Fig. 1; Fig. 4 is a schematic side view of another apparatus for accomplishing bookbinding in accordance with another embodiment of the present invention; Fig. 5 is a sectional view taken along V-V line shown in Fig. 4, Fig. 6 is a side view of a bookbinding product obtained by using the apparatus shown in Fig. 4; Fig. 7 is a schematic side view of an apparatus for accomplishing bookbinding using thermoplastic film in accordance with a further embodiment of the present invention; Fig. 8 is a sectional view taken along VI-VI line shown in Fig. 7; Fig. 9 is a side view of a bookbinding product obtained by using the apparatus shown in Fig. 7; Fig. 10 is another schematic side view of another apparatus for accomplishing bookbinding using a thermoplastic film in accordance with the present invention; Fig. 11 is a sectional view taken along XI -XI line shown in Fig. 10; Fig. 12 is a side view of a bookbinding product obtained by using the apparatus shown in Fig. 10; In Fig. 13, (A) to (E) show examples for interposing the thermoplastic film between an inner face of a spine of a cover and ends of bound sheets. In Fig. 1 and Fig. 2, reference numeral 1 indicates a cover made with a thermoplastic resin for example polypropylene, 2 shows sheets of a bag shape having a front opening and made with a thermoplastic resin of the same kine with that of the cover. 3 denotes spacer sheets made with the same kind of resin. Said spacer sheets 3 and sheets 2 are superposed by turns with arranged ends thereof. 4 is clamping means having fastening bolts 5 for securing the bound sheets 2 and the spacer sheets with a slight projection of both ends. 6 indicates a setting table which secures the clamping means 4 so as not to move in the lateral direction in Fig. 2. 7 denotes pressing means having a shallow groove in which a spine of the cover 1 fits in. An inner face of the spine is pressed onto the arranged ends of the sheets 2 and the spacer sheets 3 slightly projecting from the clamping means 4. Said pressing means 7 reciprocates in the lateral direction in Fig. 2 with a vibration amplitude of 0.5 to 2.0 mm and at a frequency of 150 to 300Hz while keeping the above pressing action. Thus there generates a friction heat between the inner face of the spine of the cover 1 and the arranged ends of the bound sheets 2 and thereby the spacer sheets 3 and the thermoplastic resins melts. Stopping the reciprocating motion of the pressing means and blowing optionally a cold air to cool them, the ends of the sheets and the spacer sheets are bonded to the inner face of the spine. Raising the pressing means 7, the cover 1 is retained at the setting table together with the bound sheets 2 and the spacer sheets 3. Detaching the clamping means 4 from the setting table and detaching the integral unit of the cover, bound sheets and spacer sheets from the clamping means, a bookbinding product having the curved spine which shows an excellent appearance is obtained as shown in Fig. 3. In Fig. 4 and Fig. 5 which show another apparatus for accomplishing bookbinding in accordance with the present invention, reference numerals 11 and 12 indicate a cover and sheets respectively which are made with the same thermoplastic resin as in the above example. 13 shows spacer sheets made with materials, for example cardboards, which are not susceptible of friction welding with a spine of the cover 11. 14 shows clamping means one of which is fixed on a table 16 and another of which is movable in the direction of an arrow on the table 16 by the action of driving means like plungers. 17 indicates pressing means which is movable up and down by the action of lifting means and to which the cover 11 is secured by any suitable means. Said pressing means 17 can be reciprocated in the lateral direction in Fig. 5 by driving means with a vibration amplitude of 0.5 to 2.0 mm and at a frequency of 150 to 300Hz. The sheets 12 and the spacer sheets 13 are superposed by turns with arranged ends thereof. Said composite sheets are set vertically on the table 16 between the clamping means 14. Moving the movable clamping means to the right hand in the drawing, the composite sheets are held by the clamping means. As shown in the drawing, upper ends of the spacer sheets 13 slightly project from upper ends of the clamping means and upper ends of the sheets 12 project from the upper ends of the spacer sheets 13 approximately by 1 mm. Then the pressing means 17 having the cover 11 secured thereto is moved downwards to press the inner face of the spine of the cover onto the upper ends of the sheets and also reciprocated laterally in Fig. 5. By a friction heat generated by the above action of the pressing means, the upper ends of the sheets are bonded by friction welding to the inner face of the spine. Stopping the reciprocating motion of the pressing means, detaching the cover from the pressing means, releasing the clamping means and detaching the spacer sheets interposed between the bound sheets, a binding product having the curved spine which shows an excellent appearance is obtained as shown in Fig. 6. In the present invention, the cover, sheets and spacer sheets are not necessarily required to be made entirely with a thermoplastic resin as far as the end portions thereof are of a thermoplastic resin. Omitting the spacer sheets, using sheets of a plain sheet form, reciprocating the pressing means in the lateral direction in Fig. 1 and Fig. 4 or reciprocating both the cover and the sheets may be all applicable in the present invention. In Fig. 7 through Fig. 13 which show further examples of apparatuses for accomplishing bookbinding in accordance with the present invention, reference numeral 18 shows sheets, 19 indicates a thermoplastic film which is interposed between an inner face of a spine of a cover and arranged ends of the sheets, 20 indicates spacer sheets, 21 is a cover. An inner face 21a of a spine of the cover 21 is made with a thermoplastic resin, for example polypropylene, polyvinyl chloride etc. Making the cover entirely with a thermoplastic resin may be preferable from the veiw point of durability and economy. Said thermoplastic film 19 may be of a plain sheet as shown in Fig 13 (A) or may be united with flap sheets 19a which are superposed on either one side or both sides of the sheets 18 as shown in Fig. 13 (D) or (E). Said thermoplastic film 19 may be also united with one or more supporting sheets 19b which are interposed between the sheets 18 as shown in Fig. 13 (B) or united with the spacer sheets 20 as shown in Fig. 13 (C). Making the flap sheets 19a and the thermoplastic film 19 with a same thermoplastic resin in a unit form may be preferable from the view point of durability and economy. The sheets 18 may be of a plain sheet form or of a bag shape which is suitable for making a file. The material of the sheets 18 may be for example papers or thermoplastic resins which can be bonded by friction welding to the cover and the thermoplastic films. In making a file, the sheets 18 of a bag shape is preferable to be made with a thermoplastic resin from the view point of processability and durability. The spacer sheets 20 may be bonded together with the bound sheets 18 to the cover 21 or may not be bonded so as to be detached from the bound sheets 18 after the sheets 18 are bonded to the cover. For bonding purpose, the spacer sheets are made with a thermoplastic resin. For detaching purpose, they are made with for example papers, metals or plastic materials which can not bonded to a thermoplastic resin to be used for the flap sheets 19a or the cover 21. Bookbinding using the apparatus shown in Fig. 7 and Fig. 8 is accomplished as follows. The upper ends of the superposed sheets 18 are arranged on a table 22. The flap sheets 19a are superposed on both sides of the sheets 18 and the thermoplastic films united with the flap sheets are overlaid on the upper ends of the sheets 18. Then the flap sheets and the sheets 18 are held by clamping means 23,24. The clamping means 23 is fixed on the table 22. The clamping means 24 is movable by means of driving means like a piston, screw and so forth. Pressing means 25 securing the cover 21 is moved downward by means of a piston, screw and so forth and presses the inner face 21a of the spine of the cover 21 on the thermoplastic films 19 and the upper ends of the sheets 18. Said pressing means 25 is then reciprocated in the lateral direction in Fig. 8 with a vibration amplitude of 0.5 to 2.0 mm and at a frequency of 150 to 300H z . Said action of the pressing means generates a friction heat between the thermoplastic films 19 and the inner face 21a of the spine of the cover to melt the resin of both the thermoplastic films and the inner face of the spine. Stopping the reciprocating motion of the pressing means, the sheets 18 and the flap sheets 19a are bonded by friction welding to the inner face of the spine. The reciprocating direction of the pressing means may be lateral in Fig. 7. The sheets 18 are bonded to the cover 21 by means of the molten thermoplastic films 19. Then it is preferable that the thermoplastic films 19 cover the upper ends of the sheets 18 entirely. A slight gap between the thermoplastic films may be admissible because the molten resin flows over and cover a entire region of the upper ends. It will be preferable that the thermoplastic films 19 are not overlapped with each other, because the overlapped portion may take a long time to be melted and the bonding time may be prolonged. The flap sheets 19a may be superposed on one side of the sheets 18. Superposing on both sides as above, an appearance of a bookbinding product is beautiful. Besides the upper end of the sheets 18 being covered by a pair of thermoplastic films 19 as shown in the drawing, the thermoplastic films can be easily set in good alignment with the sheets 18. It is preferable that lower ends of the flap sheets 19a terminate slightly inwardly of lower ends of the sheets 18. As shown in Fig. 7 and Fig. 8, the clamping means 23,24 have upper portions 23a,24a which are slidably mounted on the clamping means 23,24 by means of slidable pins and springs. The pressing means presses the inner face of the spine of the cover onto the thermoplastic films and the upper ends of the sheets 18 pressing down the upper portions 23a,24a. The thermoplastic films and the upper ends of the sheets being held by said upper portions 23a,24a, the arrangement and alignment thereof are not disturbed by the reciprocating motion of the pressing means. Adjustable upper portions which can be set on the clamping means having upper ends positioned at a same horizontal plane with the upper ends of the sheets may be also applicable. For sheets having a given dimension, the clamping means having the same dimension may be applicable without equipping an adjustable means. Being bonded to the inner face 21a of the spine of the cover 21 by means of the molten thermoplastic films 19, the sheets 18 can be also made with papers or any suitable materials instead of a thermoplastic resin. Employing the flap sheets 19a serves to bond completely and beautifully the sheets 18, especially the outermost sheets, to the inner face of the spine of the cover. When the sheets and the flap sheets have been bonded to the inner face of the spine, the cover is detached from the pressing means and the clamping means is opened. Then a bookbinding product having the curved spine which shows an excellent appearance is obtained as shown in Fig. 9. Bookbinding using the apparatus shown in Fig. 10 and Fig. 11 is accomplished as follows. Between the upper ends of the superposed sheets 18 the spacer sheets 20 are interposed. The flap sheets 19 are superposed on either both sides of the sheets as shown in Fig. 13 (D) or one side as shown in Fig. 13 (E) and the thermoplastic films or film united with the flap sheets or sheet are overlaid on the upper ends of the composite sheets consisting of the sheets 18 and the spacer sheets. Then the composite sheets are held by clamping means 26 with a slight projection of the upper ends of the composite sheets and the thermoplastic films or film. The clamping means 26 are secured by a setting table 27 which has an aperture 27a through which the composite sheets are hung down. Pressing means 25 securing the cover 21 is then moved downward to press the inner face 21a of the cover onto the thermoplastic films or film 19 and the upper end of the composite sheets. Said pressing means 25 is then reciprocated as in the same manner as described in connection with the example shown in Fig. 7 and Fig. 8 to bond by friction welding the sheets 18, flap sheets or sheet 19 and spacer sheets 20 to the inner face 21a of the spine of the cover 21. Consequently a bookbinding product having the curved spine which shows an excellent appearance is obtained as shown in Fig. 12. Shown in the drawings is an example for a file consisting of bound sheets 18 of a bag shape. The spacer sheets 20 become detachable when they are made with materials which can not be bonded by friction welding or when they are set slightly inwardly of the upper ends of the composite sheets even if they are made with a thermoplastic resin.

Claims: A method of binding sheets to a face of a cover, the material constituting the said face being thermoplastic, comprising superposing the sheets to form a stack, a region of thermoplastic material being provided along an edge of the stack, pressing an edge of the stack against the said face and causing relative motion of the cover and the edge of the stack so that the said edge bonds to the cover by means of friction heat generated in the said region and in the face by the motion, characterized in that relative reciprocatory motion of the cover and the edge of the stack is caused in a direction parallel to the contact plane therebetween to generate the said friction heat. A method as claimed in claim 1, wherein a micro vibration is applied to at least either the cover or the sheets in parallel with the contact plane to cause the said reciprocatory motion. A method as claimed in claim 1 or claim 2, wherein the ends of the sheets are thermoplastic and form the region of thermoplastic material. A method as claimed in claim 1 or claim 2, wherein the region of thermoplastic material is a film positioned between the edge of the stack and the said face. A method as claimed in claim 4, wherein the thermoplastic film has flap sheets superposed on either one side or both sides of the sheets. A method as claimed in claim 4 or claim 5, wherein the thermoplastic film has one or more supporting sheets interposed between the sheets. A bookbinding product obtainable by a method as claimed in any one of claims 4 to 6 and comprising a cover having a thermoplastic inner face at a spine and superposed bound sheets whose arranged ends are bonded to the inner face of the spine of the cover, a thermoplastic film being positioned between the inner face of the spine and the arranged ends of the bound sheets. A bookbinding product as claimed in claim 7, wherein the thermoplastic film has flap sheets superposed on either one side or both sides of the bound sheets. A bookbinding product as claimed in claim 7 or claim 8, wherein the thermoplastic film has one or more supporting sheets interposed between the bound sheets.

Inventors: NISHIKAWA, KENJIRO
Applicants: MARUNI KASEI KABUSHIKI KAISHA
Application year: 1988
Main classification: B42C11
IPC codes: B42C11