Booklet formation device and image formation device

Abstract

To provide a booklet formation device that can provide high-quality deliverables and an image formation device provided therewith.SOLUTION: A booklet formation device that forms a booklet by bonding multiple sheets includes a sheet supporting part that supports sheets coated with adhesive toner, and a bonding unit that has a pressure member and applies heat and pressure to the sheets supported on the sheet supporting part by the pressure member to melt the adhesive toner to form an adhesive layer and bond the sheets together by the adhesive layer. When forming a first booklet that includes a first number of sheets, the bonding unit operates under first operating conditions so that the adhesive layer at a position closest to the pressure member in the first booklet has a first thickness, and when forming a second booklet including a second number of sheets that is greater than the first number, the bonding unit operates under second operating conditions that are different from the first operating conditions so that the adhesive layer at a position closest to the pressure member in the second booklet has a second thickness that is thicker than the first thickness.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a booklet forming apparatus for forming a booklet and an image forming apparatus including the same. [Background technology]

[0002] Patent document 1 describes an image forming apparatus that produces a larger stack of sheet materials by repeatedly heating and pressing three sheets at a time using a heating and pressing member, each sheet having an adhesive toner layer formed thereon. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-231875 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the image forming apparatus described in Patent Document 1, the area where the adhesive toner layer is formed in the finished product, which is a stack of sheets, may be recessed compared to the area where the adhesive toner layer is not formed, which may result in a decrease in quality of the finished product.

[0005] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to provide a booklet forming apparatus capable of producing a high-quality product, and an image forming apparatus including the same. [Means for solving the problem]

[0006] According to a first aspect of the present invention, a booklet forming device that forms a booklet by bonding multiple sheets includes a sheet supporting section that supports sheets to which an adhesive toner is applied, and an adhesive unit that has a pressure member and heats and presses the sheets supported on the sheet supporting section by the pressure member to melt the adhesive toner and form an adhesive layer, and bonds the sheets together by the adhesive layer, wherein when forming a first booklet including a first number of sheets, the adhesive unit operates under first operating conditions so that the thickness of the adhesive layer at a position in the first booklet closest to the pressure member has a first thickness, and when forming a second booklet including a second number of sheets greater than the first number, the adhesive unit operates under second operating conditions different from the first operating conditions so that the thickness of the adhesive layer at a position in the second booklet closest to the pressure member has a second thickness thicker than the first thickness.

[0007] According to a second aspect of the present invention, a booklet forming device that forms a booklet by bonding multiple sheets includes a sheet supporting section that supports sheets to which an adhesive toner is applied, and an adhesive unit that has a pressure member and heats and pressurizes the sheets supported by the sheet supporting section using the pressure member to melt the adhesive toner and form an adhesive layer, and bonds the sheets together using the adhesive layer, wherein the pressure member is configured to pressurize the first number of sheets with a first pressure when forming a first booklet including a first number of sheets, and to pressurize the second number of sheets with a second pressure less than the first pressure when forming a second booklet including a second number of sheets that is greater than the first number.

[0008] According to a third aspect of the present invention, in a booklet forming device that forms a booklet by bonding multiple sheets, the device comprises a sheet supporting section that supports sheets to which an adhesive toner is applied, and an adhesive unit that has a pressure member and heats and presses the sheets supported by the sheet supporting section with the pressure member to melt the adhesive toner and form an adhesive layer, and bonds the sheets together with the adhesive layer, wherein a surface temperature of the pressure member is set to a first temperature when a first booklet including a first number of sheets is formed, and is set to a second temperature lower than the first temperature when a second booklet including a second number of sheets that is greater than the first number of sheets is formed.

[0009] According to a fourth aspect of the present invention, a booklet forming device that forms a booklet by bonding multiple sheets includes a sheet supporting section that supports sheets to which an adhesive toner is applied, and an adhesive unit that has a pressure member and heats and presses the sheets supported by the sheet supporting section with the pressure member to melt the adhesive toner and form an adhesive layer, and bonds the sheets together with the adhesive layer, wherein when forming a first booklet including a first number of sheets, the pressure member heats and presses the first number of sheets for a first time, and when forming a second booklet including a second number of sheets that is greater than the first number, the pressure member heats and presses the second number of sheets for a second time that is shorter than the first time. Effect of the Invention

[0010] According to the present invention, a high-quality product can be provided. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic diagram illustrating a cross-sectional configuration of an image forming apparatus according to a first embodiment. [Diagram 2] 1A is a diagram showing a state in which a sheet is transported to an intermediate stacking section, and FIG. 1B is a diagram showing a state in which the sheet abuts against a vertical alignment reference plate. [Diagram 3]1A is a diagram showing how the lateral alignment claws move, and FIG. 1B is a diagram showing how the edge of the sheet hits the lateral alignment reference plate. [Figure 4] FIG. [Diagram 5] FIG. 2A is a schematic diagram showing a cross section of a booklet in Comparative Example 1, and FIG. 2B is an enlarged cross-sectional view showing an adhesive layer. [Figure 6] FIG. 1(a) shows the measurement of adhesive strength for a booklet made by thermocompression bonding two sheets, and FIG. 1(b) shows the measurement of adhesive strength for a booklet made by thermocompression bonding four sheets. [Figure 7] Graph showing adhesive strength test results. [Figure 8] FIG. 11 is a schematic diagram illustrating a cross-sectional configuration of an image forming apparatus according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0013] <First embodiment> [Overall configuration of image forming device] First, the overall configuration of the image forming apparatus will be described with reference to Fig. 1. Fig. 1 is a schematic diagram showing the cross-sectional configuration of an image forming apparatus 1S according to a first embodiment.

[0014] The image forming apparatus 1S includes a printer section 1 (image forming apparatus main body) equipped with an electrophotographic image forming unit 1e, an intermediate conveying unit 26 connected to the printer section 1, and a post-processing apparatus 4 (sheet processing apparatus) connected to the intermediate conveying unit 26. The image forming apparatus 1S is an image forming system made up of a plurality of apparatuses. However, the functions of the respective apparatuses included in the image forming apparatus 1S of this embodiment may be arranged in one housing.

[0015] 1, the printer section 1 includes a cassette 8 that stores sheets P, an image forming unit 1e (inside a dashed frame) as an image forming section, a fixing device 6 as a fixing section, and a housing 19 that houses these. The printer section 1 has a printing function (image forming function) that forms a toner image on the sheet P fed from the cassette 8 by the image forming unit 1e, and performs fixing processing by the fixing device 6 to produce a printed matter. Note that the sheet P, which is the recording material (recording medium), can be a variety of sheet materials of different sizes and materials, such as paper such as plain paper and cardboard, sheet materials with surface treatments such as plastic film, cloth, and coated paper, and sheet materials with special shapes such as envelopes and index paper.

[0016] In this embodiment, the maximum size of the sheet P on which the printer unit 1 can form an image is A4 size (297 mm length × 210 mm width). The printer unit 1 can form an image by transporting the A4 size sheet P in the vertical direction (long side feed direction, the direction in which the vertical side of the A4 size sheet P is parallel to the sheet transport direction).

[0017] The image forming unit 1e is a tandem-type intermediate transfer electrophotographic unit equipped with four process cartridges 7n, 7y, 7m, and 7c, a scanner unit 2 as an exposure device, and a transfer unit 3. A process cartridge is a unit in which multiple parts responsible for the image forming process are integrated into one replaceable unit.

[0018] As described later, the image forming unit 1e also functions as an application unit that applies adhesive to the sheet P. The image forming apparatus 1S including the image forming unit 1e as an application unit and a booklet production device 50 described later is an example of a sheet bonding apparatus that produces a product in which the sheets P are bonded together.

[0019] Each process cartridge 7n, 7y, 7m, 7c has a substantially common configuration except for the type of powder contained in the four powder containers Gn, Gy, Gm, Gc. That is, each process cartridge 7n, 7y, 7m, 7c has a photosensitive drum Dn, Dy, Dm, Dc as an image carrier, a charging roller Cn, Cy, Cm, Cc as a charger, and a powder container Gn, Gy, Gm, Gc. Each charging roller Cn, Cy, Cm, Cc functions as a charging unit that charges the corresponding photosensitive drum Dn, Dy, Dm, Dc. Each powder container Gn, Gy, Gm, Gc contains toner, which is a powder. In addition, the powder storage sections Gn, Gy, Gm, and Gc are provided with developing rollers Hn, Hy, Hm, and Hc as developer carriers that carry toner, and the developing rollers Hn, Hy, Hm, and Hc supply toner to the corresponding photosensitive drums Dn, Dy, Dm, and Dc.

[0020] Of the four process cartridges 7n, 7y, 7m, and 7c, the three process cartridges 7y, 7m, and 7c from the right end in the figure are process cartridges for forming a visible image on a sheet P. The process cartridges 7y, 7m, and 7c create yellow, magenta, and cyan toner images, respectively. The yellow, magenta, and cyan toners contained in the process cartridges 7y, 7m, and 7c are image forming toners (recording toners for recording information, printing toners, and image toners) for forming an image on a sheet P. That is, the powder containers Gy, Gm, and Gc of the process cartridges 7y, 7m, and 7c contain yellow, magenta, and cyan image toners Ty, Tm, and Tc, respectively.

[0021] In contrast, the process cartridge 7n at the left end in the figure is a process cartridge for applying adhesive toner (adhesive toner, powder adhesive, powder adhesive) to the sheet P for bonding sheets together after printing. The process cartridge 7n creates a toner image of adhesive toner (adhesive toner image) for applying adhesive to the sheet P by the same electrophotographic process as the process cartridges 7y, 7m, and 7c. That is, the powder storage section Gn of the process cartridge 7n stores adhesive toner Tn for bonding sheets together after printing. That is, some of the cartridges of the multiple process cartridges 7n, 7y, 7m, and 7c provided in the image forming unit 1e create a visible image using image toner, and other cartridges form an adhesive layer on the sheet P using adhesive toner. The adhesive toner may be a colorless transparent toner or a colored toner. The image forming unit 1e forms an adhesive toner image in an adhesive area on the sheet using adhesive toner, and forms an image in an image area different from the adhesive area on the sheet using image forming toner.

[0022] In this embodiment, when forming a black image such as text, the black color is expressed by process black obtained by superimposing yellow, magenta, and cyan toners. However, for example, a fifth process cartridge using black toner may be added to the image forming unit 1e so that a black image can be expressed by black image toner. Not limited to this, the types and numbers of image toners and adhesive toners can be changed depending on the application of the image forming apparatus 1S.

[0023] The scanner unit 2 is disposed below the process cartridges 7n, 7y, 7m, and 7c and above the cassette 8. The scanner unit 2 is an example of an exposure section that forms an electrostatic latent image by irradiating and exposing the photosensitive drums Dn, Dy, Dm, and Dc of each of the process cartridges 7n, 7y, 7m, and 7c with laser light. The scanner unit 2 includes, for example, a semiconductor laser as a light source and a polygon mirror.

[0024] The transfer unit 3 of this embodiment includes a transfer belt 3a as an intermediate transfer body (secondary image carrier), a secondary transfer opposing roller 3b, and a drive roller 3c. The transfer belt 3a is a belt member stretched around the secondary transfer opposing roller 3b and the drive roller 3c. The outer circumferential surface of the transfer belt 3a faces the photosensitive drums Dn, Dy, Dm, and Dc of the process cartridges 7n, 7y, 7m, and 7c. Primary transfer rollers Fn, Fy, Fm, and Fc are disposed on the inner circumferential side of the transfer belt 3a at positions corresponding to the photosensitive drums Dn, Dy, Dm, and Dc. The transfer belt 3a is transported in a counterclockwise direction in the figure by the rotational drive of the drive roller 3c.

[0025] The printer unit 1 includes a secondary transfer roller 5 at a position facing the secondary transfer opposing roller 3b across the transfer belt 3a. A transfer nip 5n between the secondary transfer roller 5 and the transfer belt 3a is a transfer unit (secondary transfer unit) for transferring a toner image from the transfer belt 3a to the sheet P.

[0026] The fixing device 6 is an example of a fixing section that fixes the toner image formed on the sheet P to the sheet P. The fixing device 6 is a thermal fixing type device (image heating device) that fixes the toner image by heating.

[0027] The fixing device 6 has a heating film 6b as a fixing member, a ceramic heater 6a as a heat source (heating section) built into the heating film 6b, and a pressure roller 6c as an opposing member facing the heating film 6b. The heating film 6b may be heated by a halogen lamp or an induction heating type heat generating mechanism. The pressure roller 6c is driven to rotate by a driving source (not shown). In addition, the heating film 6b and the pressure roller 6c are pressed against each other by a biasing member such as a spring, and a fixing nip 6n is formed between the heating film 6b and the pressure roller 6c. That is, the sheet P is heated and pressed when passing through the fixing nip 6n.

[0028] The control unit of the image forming apparatus 1S adjusts the power input to the ceramic heater 6a based on the detection result of a radiation thermometer (not shown) to control the temperature so that the heating film 6b reaches a predetermined target temperature (fixing temperature). The ceramic heater 6a is not limited to being in direct contact with the heating film 6b, and may be in contact with the heating film 6b via a sheet material having high thermal conductivity, such as an iron alloy or aluminum.

[0029] The heating film 6b is a thin film made of a highly heat-resistant resin such as polyimide resin or polyamide-imide resin, or a metal such as stainless steel, but a heating roller having rigidity may be used instead of the heating film 6b.

[0030] [Outline of image toner] As the image toner (Ty, Tm, Tc) of the present embodiment, a known image toner can be used. Among them, an image toner using a thermoplastic resin as a binder resin is preferred. The thermoplastic resin is not particularly limited, and resins that have been used in image toners in the past, such as polyester resin, vinyl resin, acrylic resin, and styrene-acrylic resin, can be used. A plurality of these resins may be contained. Among them, it is more preferred to use an image toner using a styrene-acrylic resin. The image toner may contain a colorant, a magnetic material, a charge control agent, a wax, an external additive, and the like.

[0031] [Example of manufacturing method of image toner] An example of a method for producing the image toner used in this embodiment is as follows. Styrene 60.0 parts Colorant 6.5 parts (CI Pigment Blue 15:3, Dainichi Seika Chemicals Co., Ltd.) The above materials were placed in an attritor (manufactured by Mitsui Miike Chemical Engineering Co., Ltd.), and further dispersed using zirconia particles having a diameter of 1.7 mm at 220 rpm for 5 hours to obtain a pigment dispersion liquid.

[0032] Styrene 15.0 parts n-Butyl acrylate 25.0 parts Polyester resin 4.0 parts (Polyester resin with weight average molecular weight (Mw) of 20,000, glass transition temperature (Tg) of 75°C, and acid value of 8.2 mgKOH / g) Behenyl behenate 12.0 parts (Ester wax made by esterifying behenic acid and behenyl alcohol) Divinylbenzene 0.5 parts The above materials were mixed and added to the pigment dispersion liquid. The resulting mixture was kept at 60° C. and stirred at 500 rpm using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) to dissolve and disperse uniformly, thereby preparing a polymerizable monomer composition.

[0033] Meanwhile, 850.0 parts of 0.10 mol / L-Na3PO4 aqueous solution and 8.0 parts of 10% hydrochloric acid were added to a container equipped with a high-speed stirring device Clearmix (manufactured by M Technique Co., Ltd.), the rotation speed was adjusted to 15,000 rpm, and the temperature was heated to 70°C. 127.5 parts of 1.0 mol / L-CaCl2 aqueous solution were added to this to prepare an aqueous medium containing a calcium phosphate compound.

[0034] After the polymerizable monomer composition was added to the aqueous medium, 7.0 parts of t-butyl peroxypivalate, a polymerization initiator, was added, and the mixture was granulated for 10 minutes while maintaining a rotation speed of 15,000 rpm. After that, the high-speed agitator was replaced with a propeller agitator, and the mixture was reacted at 70°C for 5 hours under reflux, and then the liquid temperature was increased to 85°C and the mixture was reacted for another 2 hours.

[0035] After the polymerization reaction was completed, the resulting slurry was cooled, and then hydrochloric acid was added to the slurry to adjust the pH to 1.4 and the slurry was stirred for 1 hour to dissolve the calcium phosphate salt.The slurry was then washed with three times the amount of water, filtered, dried, and classified to obtain toner particles.

[0036] Thereafter, silica fine particles (number average particle diameter of primary particles: 10 nm, BET specific surface area: 170 m) that had been hydrophobized using dimethyl silicone oil (20% by mass) were added to 100.0 parts of the toner particles as an external additive.2 The mixture was mixed at 3000 rpm for 15 minutes using a Mitsui Henschel mixer (manufactured by Mitsui Miike Chemical Engineering Co., Ltd.) to obtain a toner. The weight average particle diameter of the obtained toner was 6.5 μm.

[0037] [Outline of adhesive toner] The adhesive toner (Tn) of the present embodiment can be a toner containing a thermoplastic resin. The resin that can be used for the thermoplastic resin is not particularly limited, and includes known thermoplastic resins such as polyester resin, vinyl resin, acrylic resin, styrene acrylic resin, polyethylene, polypropylene, polyolefin, ethylene-vinyl acetate copolymer resin, and ethylene-acrylic acid copolymer resin. A plurality of these resins may be contained.

[0038] The adhesive toner Tn preferably further contains a wax. As the wax, known waxes such as ester waxes, which are esters of alcohol and acid, and hydrocarbon waxes such as paraffin wax can be used. The adhesive toner Tn may contain a colorant. As the colorant, known colorants such as black colorants, yellow colorants, magenta colorants, and cyan colorants can be used. The adhesive toner Tn as an adhesive toner may contain a magnetic material, a charge control agent, a wax, and an external additive.

[0039] In order to form an adhesive portion by the adhesive toner Tn on the sheet P by using the electrophotographic method, the weight average particle diameter of the adhesive toner Tn is preferably 5.0 μm or more and 30 μm or less, and more preferably 6.0 μm or more and 20 μm or less. In addition, as long as it satisfies the adhesive property, an image toner may be used as the adhesive toner Tn.

[0040] [Example of adhesive toner manufacturing method] An example of a method for producing the adhesive toner Tn used in this embodiment is as follows. Styrene 75.0 parts n-Butyl acrylate 25.0 parts Polyester resin 4.0 parts (Polyester resin with weight average molecular weight (Mw) of 20,000, glass transition temperature (Tg) of 75°C, and acid value of 8.2 mgKOH / g) Ethylene glycol distearate 14.0 parts (Ester wax made by esterifying ethylene glycol and stearic acid) Hydrocarbon wax (HNP-9, Nippon Seiro) 2.0 parts Divinylbenzene 0.5 parts The mixture of the above materials was kept at 60° C. and stirred at 500 rpm using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) to dissolve uniformly, thereby preparing a polymerizable monomer composition.

[0041] Meanwhile, 850.0 parts of 0.10 mol / L-Na3PO4 aqueous solution and 8.0 parts of 10% hydrochloric acid were added to a container equipped with a high-speed stirring device Clearmix (manufactured by M Technique Co., Ltd.), the rotation speed was adjusted to 15,000 rpm, and the temperature was heated to 70°C. 127.5 parts of 1.0 mol / L-CaCl2 aqueous solution were added to this to prepare an aqueous medium containing a calcium phosphate compound.

[0042] After the polymerizable monomer composition was added to the aqueous medium, 7.0 parts of t-butyl peroxypivalate, a polymerization initiator, was added, and the mixture was granulated for 10 minutes while maintaining a rotation speed of 15,000 rpm. After that, the high-speed agitator was replaced with a propeller agitator, and the mixture was reacted at 70°C for 5 hours under reflux, and then the liquid temperature was increased to 85°C and the mixture was reacted for another 2 hours.

[0043] After the polymerization reaction was completed, the resulting slurry was cooled, and then hydrochloric acid was added to the slurry to adjust the pH to 1.4 and stirred for 1 hour to dissolve the calcium phosphate salt.The slurry was then washed with three times the amount of water, filtered, dried, and classified to obtain adhesive toner particles.

[0044] Thereafter, silica fine particles (number average particle diameter of primary particles: 10 nm, BET specific surface area: 170 m) that had been hydrophobized using dimethyl silicone oil (20% by mass) were added to 100.0 parts of the adhesive toner particles as an external additive. 2 The mixture was mixed at 3000 rpm for 15 minutes using a Mitsui Henschel mixer (manufactured by Mitsui Miike Chemical Engineering Co., Ltd.) to obtain an adhesive toner. The weight average particle diameter of the obtained adhesive toner was 6.8 μm.

[0045] [Method for measuring weight average particle size] The weight average particle diameter of the image toner and adhesive toner Tn was calculated as follows. The measurement device used was a precision particle size distribution measurement device using the narrow hole electrical resistance method, "Coulter Counter Multisizer 3" (registered trademark product name, manufactured by Beckman Coulter, Inc.), equipped with a 100 μm aperture tube. The measurement conditions were set and the measurement data was analyzed using the accompanying dedicated software "Beckman Coulter Multisizer 3 Version 3.51" (manufactured by Beckman Coulter, Inc.). The measurement was performed with an effective measurement channel count of 25,000 channels.

[0046] The electrolyte solution used for the measurements was prepared by dissolving special grade sodium chloride in ion-exchanged water to a concentration of 1% by mass, for example, "ISOTON II" (manufactured by Beckman Coulter).

[0047] Before performing the measurements and analysis, the dedicated software was set as follows. In the "Change Standard Measurement Method (SOM)" screen of the dedicated software, the total count number in the control mode was set to 50,000 particles, the number of measurements was set to 1, and the Kd value was set to the value obtained using "Standard particle 10.0 μm" (manufactured by Beckman Coulter). The threshold and noise level were automatically set by pressing the "Threshold / Noise Level Measurement Button". In addition, the current was set to 1600 μA, the gain to 2, the electrolyte to ISOTON II, and "Flush aperture tube after measurement" was checked. In the "Pulse to particle size conversion setting" screen of the dedicated software, the bin interval was set to logarithmic particle size, the particle size bin to 256 particle size bin, and the particle size range to 2 μm to 60 μm.

[0048] The specific measurement method is as follows. (1) 200 mL of the electrolyte solution was placed in a 250 mL round-bottom glass beaker made exclusively for the Multisizer 3, which was then set on the sample stand. The stirrer rod was stirred counterclockwise at 24 revolutions per second. Dirt and air bubbles in the aperture tube were then removed using the "aperture tube flush" function of the dedicated software. (2) 30 mL of the electrolyte solution was placed in a 100 mL flat-bottom glass beaker, and 0.3 mL of a solution prepared by diluting "Contaminon N" (a 10% aqueous solution of a pH 7 neutral detergent for cleaning precision measuring instruments, consisting of a nonionic surfactant, an anionic surfactant, and an organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) three times by mass with ion-exchanged water was added as a dispersant. (3) An ultrasonic disperser "Ultrasonic Dispersion System Tetora150" (manufactured by Nikkaki Bios Co., Ltd.) was prepared, which has two built-in oscillators with an oscillation frequency of 50 kHz and a phase difference of 180 degrees, and an electrical output of 120 W. 3.3 L of ion-exchanged water was placed in the water tank of the ultrasonic disperser, and 2 mL of Contaminon N was added to this water tank. (4) The beaker (2) was set in the beaker fixing hole of the ultrasonic disperser, and the ultrasonic disperser was operated. Then, the height of the beaker was adjusted so that the resonance state of the electrolyte solution in the beaker was maximized. (5) While the electrolyte solution in the beaker in (4) was irradiated with ultrasonic waves, the toner or adhesive toner was added to the electrolyte solution in small amounts of 10 mg at a time and dispersed. The ultrasonic dispersion process was continued for another 60 seconds. During the ultrasonic dispersion, the water temperature in the water tank was appropriately adjusted to be between 10°C and 40°C. (6) The electrolytic solution (5) in which the toner or adhesive toner was dispersed was dropped using a pipette into the round-bottom beaker (1) placed in the sample stand, and the measurement concentration was adjusted to 5%. Then, the measurement was continued until the number of particles measured reached 50,000. (7) The measurement data was analyzed using dedicated software provided with the device, and the weight average particle size was calculated.

[0049] [Image formation operation] Next, an image forming operation of the printer unit 1 will be described (see FIG. 1). The image forming operation is a series of operations in which the printer unit 1 conveys the sheets P one by one, creates a toner image on the sheets P with image toner, and applies adhesive toner to a predetermined adhesive area on the sheets P. When a print instruction accompanied by image data to be printed is input to the image forming apparatus 1S, the control unit of the image forming apparatus 1S starts the image forming operation.

[0050] When the image forming operation is started, the sheets P stored in the cassette 8 are fed one by one from the cassette 8 by the feeding roller 8a. The printer unit 1 can also feed the sheets P set in the multi-tray 20 (manual feed tray, multipurpose tray) one by one. The fed sheets P are transported toward the transfer nip 5n by the transport roller pair 8b.

[0051] In parallel with the feeding of the sheet P, in the image forming unit 1e, the process cartridges 7n, 7y, 7m, and 7c are sequentially driven, and the photosensitive drums Dn, Dy, Dm, and Dc are rotated. The surfaces of the photosensitive drums Dn, Dy, Dm, and Dc are uniformly charged by the charging rollers Cn, Cy, Cm, and Cc. In addition, the scanner unit 2 irradiates the photosensitive drums Dn, Dy, Dm, and Dc with laser light modulated based on image data, thereby forming an electrostatic latent image on the surface of each of the photosensitive drums Dn, Dy, Dm, and Dc.

[0052] The developing rollers Hn, Hy, Hm, and Hc of the process cartridges 7n, 7y, 7m, and 7c supply toner (image toner, adhesive toner) as a developer to the photosensitive drums Dn, Dy, Dm, and Dc, respectively, to develop the electrostatic latent image into a toner image. Note that the adhesive toner image formed on the photosensitive drum Dn by the adhesive toner Tn is different from a toner image of image toner (normal toner image) for printing images such as text and figures on the sheet P in that it is not intended to transmit visual information. However, in the following description, the adhesive toner image (adhesive layer formed by the adhesive toner Tn) developed by the electrophotographic process to form an adhesive toner image in a predetermined pattern on the sheet P is also treated as one of the "toner images."

[0053] The toner images formed in each process cartridge 7n, 7y, 7m, 7c are transferred (primary transfer) from each photosensitive drum to the transfer belt 3a by an electric field formed between the photosensitive drums Dn, Dy, Dm, Dc and the primary transfer rollers Fn, Fy, Fm, Fc. The toner images carried on the transfer belt 3a and reaching the transfer nip 5n are transferred (secondary transfer) to the sheet P fed and conveyed from the cassette 8 by an electric field formed between the secondary transfer roller 5 and the secondary transfer opposing roller 3b.

[0054] Thereafter, the sheet P is conveyed to the fixing device 6 and subjected to a thermal fixing process. That is, when the sheet P passes through the fixing nip 6n, the toner image on the sheet P is heated and pressurized, so that the image toner and adhesive toner melt, and then are fixed to the sheet P.

[0055] A switching guide 21 is disposed downstream of the fixing nip 6n in the sheet transport direction. The switching guide 21 is a guide member for switching the transport path of the sheet P based on single-sided / double-sided setting specified in a print instruction.

[0056] In the case of a single-sided mode (single-sided printing) in which a toner image is formed only on one side of the sheet P, the switching guide 21 guides the sheet P toward the discharge roller pair 22. In the case of a double-sided mode (double-sided printing) in which an image is formed on both sides of the sheet P, the switching guide 21 guides the sheet P on which a toner image is formed on the front side toward the reversing roller pair 23 (switchback roller pair). The reversing roller pair 23 conveys the sheet P in a first direction, and then switches back to convey the sheet P in a second direction opposite to the first direction before the rear end of the sheet passes through the nip portion of the reversing roller pair 23. The sheet P switched back by the reversing roller pair 23 is conveyed via the double-sided conveying path 27, and passes through the transfer nip 5n and the fixing nip 6n again, thereby forming a toner image on the rear side. The sheet P on which the toner image is formed on the rear side is guided by the switching guide 21 toward the discharge roller pair 22.

[0057] The discharge roller pair 22 discharges the sheet P to the outside of the printer unit 1. This completes the image forming operation for one sheet P. In the present embodiment, the sheet P discharged from the discharge roller pair 22 is received by the intermediate transport unit 26. The intermediate transport unit 26 transports the sheet P toward the post-processing device 4 by the transport roller pairs 24 and 25.

[0058] An operation panel 81 is provided on the housing 19 of the printer unit 1, and the operation panel 81 has a liquid crystal display unit 82 that can be viewed and touched by the user. The control unit displays the operating status of the printer unit 1 and the status of consumables such as toner on the liquid crystal display unit 82. The liquid crystal display unit 82 also has a navigation function that guides the user through specific operations.

[0059] [Post-processing device] 1, the post-processing device 4 of this embodiment has a floor-standing configuration. In other words, the post-processing device 4 is installed on the installation surface on which the printer unit 1 is installed, and is arranged side by side with the printer unit 1 in the horizontal direction.

[0060] The post-processing device 4 includes a conveying path for conveying the sheet P received from outside, a plurality of pairs of conveying rollers arranged along the conveying path, an entrance sensor 30a, a booklet making device 50 for making a booklet by gluing a plurality of sheets P together, an upper discharge tray 33 and a lower discharge tray 34.

[0061] In this embodiment, the multiple transport roller pairs are an entrance roller pair 30, a first roller pair 31, a discharge reverse roller pair 32, a second roller pair 36, a third roller pair 37, an inner discharge roller pair 38, and a booklet discharge roller pair 39. The entrance roller pair 30, the first roller pair 31, and the discharge reverse roller pair 32 are arranged on a first transport path from a receiving entrance that receives the sheet P from the outside toward the upper discharge tray 33. The second roller pair 36, the third roller pair 37, and the inner discharge roller pair 38 are arranged on a second transport path from the discharge reverse roller pair 32 toward the booklet production device 50. The booklet discharge roller pair 39 is arranged on a third transport path from the booklet production device 50 toward the lower discharge tray 34.

[0062] The upper discharge tray 33 is a stacking section on which sheets P that are not processed by the booklet production device 50 are stacked. The lower discharge tray 34 is a stacking section on which booklets processed by the booklet production device 50 are stacked. The pair of discharge reversing rollers 32 is a discharge section that discharges the sheets P to the upper discharge tray 33. The pair of discharge reversing rollers 32 is also a reversing section that switches back the sheets P transported on the first transport path and sends them to the second transport path. The pair of booklet discharge rollers 39 is a discharge section that discharges the booklets transported on the third transport path. The housing of the post-processing device 4 is provided with a discharge outlet through which the sheets P are discharged toward the upper discharge tray 33 and a booklet discharge outlet 40 through which the booklets are discharged toward the lower discharge tray 34.

[0063] The post-processing device 4 also has a control unit 90. The control unit 90 has a CPU (Central Processing Unit) 91, a ROM (Read Only Memory) 92, and a RAM (Random Access Memory) 93. Various programs are stored in the ROM 92, and the CPU 91 reads and executes the programs from the ROM 92. The RAM 93 is used as a working area for the CPU 91.

[0064] The operation of the post-processing device 4 will be described. The sheet P conveyed from the intermediate conveying unit 26 is conveyed to the discharge reverse roller pair 32 via the entrance roller pair 30 and the first roller pair 31. The first roller pair 31 increases the rotation speed and accelerates the sheet P based on the entrance sensor 30a detecting the rear end of the sheet P. If the printing instruction specifies that the sheet P is not to be bonded (no booklet is to be produced), the sheet P is discharged as is by the discharge reverse roller pair 32 and stacked on the upper discharge tray 33. At this time, when the rear end of the sheet P comes between the first roller pair 31 and the discharge reverse roller pair 32, the conveying speed of the sheet P is decelerated to a predetermined discharge speed, and the sheet P is discharged toward the upper discharge tray 33.

[0065] When the printing instruction specifies that the sheet P should be glued (a booklet should be produced), the sheet P is switched back by the discharge / reverse roller pair 32. That is, the discharge / reverse roller pair 32 transports the sheet P in a first direction (discharge direction), and when the rear end of the sheet P in the first direction passes through the reversal flap 35, the discharge / reverse roller pair 32 reverses the sheet transport direction to a second direction opposite to the first direction, and sends the sheet P into the second transport path. The sheet P passes through a second roller pair 36 and a third roller pair 37, and is discharged to the booklet production device 50 by the inner discharge roller pair 38.

[0066] The booklet production device 50, which serves as a booklet forming device, produces a booklet by adhering a plurality of sheets P together with adhesive toner. Details of the booklet production device 50 will be described later. The booklet discharge roller pair 39 discharges the booklet conveyed from the booklet production device 50 to the outside of the post-processing device 4 through the booklet discharge port 40. The discharged booklet is stacked on the lower discharge tray 34.

[0067] [Booklet production device] Next, a description will be given of the booklet production apparatus 50. As shown in Fig. 1, the booklet production apparatus 50 has an intermediate stacking section 51 as a sheet supporting section on which a sheet bundle to be processed is supported, an alignment mechanism for aligning the stacked sheet bundles, and a thermocompression bonding unit 60 for thermocompression bonding the sheet bundles.

[0068] The alignment mechanism aligns the sheets conveyed to the intermediate stacking section 51 to a position for performing thermocompression bonding (adhesive operation) in the thermocompression bonding unit 60. A method for aligning a sheet stack using the alignment mechanism will be described with reference to Figs. 2(a) to 3(b). Figs. 2(a) to 3(b) show the booklet making apparatus 50 as viewed from a direction perpendicular to the sheet stacking surface of the intermediate stacking section 51 (height direction). In the following description, the direction along the sheet stacking surface in which the sheets P are conveyed toward the intermediate stacking section 51 is referred to as the "vertical direction" or "X direction", and the direction along the sheet stacking surface that is perpendicular to the vertical direction (X direction) is referred to as the "lateral direction" or "Y direction".

[0069] As shown in FIG. 2(a), the alignment mechanism includes a vertical alignment reference plate 52, a vertical alignment roller 53, a horizontal alignment reference plate 55, and a horizontal alignment claw 54. The vertical alignment reference plate 52 is a reference for the position of the sheet in the vertical direction. The horizontal alignment reference plate 55 is a reference for the position of the sheet in the horizontal direction. The vertical alignment roller 53 is an example of a first moving member that moves the sheet P toward the vertical alignment reference plate 52, and in this embodiment, is a half-moon roller having a part of its outer circumferential surface formed in a linear shape. By configuring the vertical alignment roller 53 as a half-moon roller in this way, even if the vertical alignment roller 53 rotates in a state in which the sheet P abuts against the vertical alignment reference plate 52, it is possible to suppress the formation of wrinkles or folds in the sheet P. The horizontal alignment claw 54 is an example of a second moving member that moves the sheet P toward the horizontal alignment reference plate 55.

[0070] As shown in FIG. 2A, the sheet P conveyed to the pair of inner discharge rollers 38 is discharged to the intermediate stacking section 51 by the pair of inner discharge rollers 38. As shown in FIG. 2B, when the rear end of the sheet P in the vertical direction passes through the pair of inner discharge rollers 38, the vertical alignment roller 53 moves the sheet P in the vertical direction, and the end of the sheet P in the vertical direction abuts against the vertical alignment reference plate 52. This aligns the position of the sheet P in the vertical direction. Note that, as shown in FIG. 1, a bundle pressing member 45 is rotatably supported near the pair of inner discharge rollers 38, and the bundle pressing member 45 presses the rear end of the sheet P stacked on the intermediate stacking section 51 against the intermediate stacking section 51. This makes it possible to prevent interference between the rear end of the preceding sheet stacked on the intermediate stacking section 51 and the leading end of the succeeding sheet discharged by the pair of inner discharge rollers 38 toward the intermediate stacking section 51.

[0071] 3(a), the lateral alignment claw 54 comes into contact with a first end of the sheet P in the lateral direction, and moves the sheet P toward the lateral alignment reference plate 55. Then, as shown in FIG. 3(b), the second end of the sheet P in the lateral direction abuts against the lateral alignment reference plate 55. This causes the position of the sheet P in the lateral direction to be aligned.

[0072] The booklet making device 50 aligns each sheet P of the sheet stack stacked on the intermediate stacking section 51 in the vertical and horizontal directions as described above. The thermocompression bonding unit 60, which will be described next, thermocompresses the aligned sheet stack to bond the sheets together via the adhesive toner. After the sheet stack is aligned in the vertical and horizontal directions by the alignment mechanism, it is bonded into a booklet by the thermocompression bonding unit 60, making it possible to create a booklet that is aligned with high precision.

[0073] 2(a) to 3(b), the case where the sheets P are conveyed one by one to the booklet making device 50 has been described, but a configuration in which a plurality of sheets P in a pre-stacked state are conveyed to the booklet making device 50 may also be used. For example, after the preceding sheet is switched back by the discharge reverse roller pair 32, the preceding sheet is temporarily stopped by the second roller pair 36. Thereafter, in accordance with the timing at which the subsequent sheet reaches the discharge reverse roller pair 32, the second roller pair 36 conveys the preceding sheet toward the discharge reverse roller pair 32. As a result, a sheet bundle in which the preceding sheet and the subsequent sheet are overlapped is formed at the discharge reverse roller pair 32. Also, by replacing the "preceding sheet" with the preceding sheet bundle already overlapped, and replacing the "subsequent sheet" with the subsequent sheet, a sheet bundle of three or more sheets can be produced. The sheet bundle already overlapped by the discharge reverse roller pair 32 is stacked on the intermediate stacking section 51 by the inner discharge roller pair 38 via the second roller pair 36 and the third roller pair 37.

[0074] As described above, the mechanism for stacking the succeeding sheets while reciprocating the preceding sheet (stack) between the pair of discharge and reversing rollers 32 and the pair of second rollers 36 is an example of a buffer mechanism (stacking section) that transports a plurality of sheets in a stacked state toward the intermediate stacking section 51. Other known mechanisms may be used as the buffer mechanism (stacking section).

[0075] When a plurality of sheets P that have been stacked in advance are transported to the booklet production apparatus 50, the alignment mechanism of the booklet production apparatus 50 can perform an alignment operation as follows. When a plurality of sheets P are stacked, the sheets are offset from each other in advance so that the lower sheet P protrudes toward the downstream side in the vertical direction (the side closer to the vertical alignment reference plate 52) than the upper sheet P on the intermediate stacking unit 51. When the rear end of the lowermost sheet P passes through the pair of inner discharge rollers 38, the vertical alignment roller 53 moves the lowermost sheet P in the vertical direction and abuts it against the vertical alignment reference plate 52. Similarly, every time the rear end of the uppermost sheet P passes through the pair of inner discharge rollers 38, the vertical alignment roller 53 moves the sheet P in the vertical direction and abuts it against the vertical alignment reference plate 52. As a result, the positions of the plurality of sheets P in the vertical direction are aligned. After the positions of the multiple sheets P in the vertical direction are aligned, the horizontal alignment claws 54 move the multiple sheets P toward the horizontal alignment reference plate 55 and bring them together against the horizontal alignment reference plate 55. This causes the positions of the multiple sheets P in the horizontal direction to be aligned.

[0076] [Thermocompression unit] The thermocompression unit 60 of the booklet production apparatus 50 will be described. Fig. 4 is a cross-sectional view of the thermocompression unit 60 cut along a plane perpendicular to the vertical direction (X direction). In the description of the booklet production apparatus 50, the direction perpendicular to the sheet stacking surface of the intermediate stacking section 51 (the direction perpendicular to both the X direction and the Y direction) is referred to as the "height direction" or "Z direction". In the description of the booklet production apparatus 50, unless otherwise specified, "downward" refers to the downward direction in the height direction (Z direction), and "upward" refers to the upward direction in the height direction (Z direction).

[0077] The thermocompression bonding unit 60 is an example of a bonding unit that bonds sheets together. The thermocompression bonding unit 60 has a pressure plate 62, a receiving plate 67, a heater 70, a heater support 63, a metal stay 66, and a pressure lever 65. The pressure plate 62 is an example of a pressure member (first pressure member, heating and pressing member) that presses the sheet P. The metal stay 66 transmits the pressure force from the pressure lever 65 to the pressure plate 62 via the heater support 63 and the heater 70. The receiving plate 67 is an example of a receiving member (second pressure member) that receives the pressure force of the pressure plate 62 and presses the sheet P together with the pressure plate 62. The heater 70 is an example of a heat source that heats the pressure plate 62.

[0078] The heater 70 may be a ceramic heater having a resistance heating element 72 formed on a ceramic substrate 71. The substrate 71 is, for example, a plate having a thickness of 1.0 mm. The pressure plate 62 is in contact with the lower surface of the heater 70 (the surface on the lower side in the figure). The pressure plate 62 is, for example, a plate member made of aluminum having a thickness of 1.5 mm. By reducing the thermal capacity of the heater 70 and the pressure plate 62 in this manner, it is possible to reduce the power consumption of the thermocompression bonding unit 60. Note that the substrate 71 of the heater 70 may be made of a material having high rigidity, such as metal, other than ceramic.

[0079] The pressure plate 62 is suitably made of a material having a small heat capacity and high thermal conductivity in order to efficiently transfer heat from the heat source to the sheet P. The heater 70 generates heat by passing electricity through the resistance heating element 72. A control unit 90 provided in the post-processing device 4 controls the power input to the resistance heating element 72 based on the temperature detected by a thermistor 64 serving as a temperature detection unit, thereby setting the pressure plate 62 to a predetermined target temperature suitable for thermocompression bonding of the sheet P. The thermistor 64 in this embodiment is supported by a heater support 63 and is in contact with the upper surface of the heater 70 (the surface opposite to the surface of the heater 70 facing the pressure plate 62).

[0080] The heater support 63 supports the heater 70. The heater support 63 is made of a material such as liquid crystal polymer, which is a type of highly heat-resistant functional resin. The heater support 63 is supported by a metal stay 66. The pressure plate 62, the heater 70, the heater support 63, and the metal stay 66 form a moving unit (heater unit) that moves back and forth in the Z direction to approach and move away from the receiving plate 67. The metal stay 66 is a reinforcing member (rigidity member) that increases the rigidity of the moving unit.

[0081] The pressure lever 65 is fastened to a metal stay 66, and reciprocates in the Z direction by the driving force of a driving source (not shown). When the pressure lever 65 moves the moving unit downward, the pressure plate 62 comes into contact with the uppermost sheet of the sheet stack on the receiving plate 67. The range of pressure applied to the sheet stack by the pressure plate 62 is, for example, 300 mm in the X direction (vertical direction) and 4.0 mm in the Y direction (horizontal direction). When the pressure lever 65 moves the moving unit upward, the pressure plate 62 moves away (retracts) from the sheet stack on the receiving plate 67.

[0082] The receiving plate 67 is a plate-like member made of silicone rubber having a thickness of, for example, 2.0 mm, and is supported by the frame of the booklet producing device 50 (the frame of the post-processing device 4). The receiving plate 67 has a role of applying a stable pressure to the sheet stack by receiving the sheet stack pressed by the pressure lever 65. The pressure applied by the pressure plate 62 to the sheet stack can be controlled by the amount of pressure applied by the pressure lever 65 against the moving unit.

[0083] The material of the receiving plate 67 is not limited to silicone rubber. The material of the receiving plate 67 is preferably one that has a certain degree of deformability, is resistant to repeated stress, and is heat resistant in order to stably transmit pressure to the sheet stack.

[0084] The thermocompression unit 60 performs a thermocompression operation (adhesive operation) in which the pressure plate 62 applies pressure and heat to the sheet stack. Specifically, in the thermocompression operation, the pressure plate 62, which has been preheated to a target temperature, is pressed against the sheet stack for a predetermined time (for example, 2.0 seconds), and then the pressure plate 62 is separated from the sheet stack. The sheet stack is pressed by being sandwiched between the pressure plate 62 and the receiving plate 67, and is heated by the pressure plate 62 heated by the heat of the heater 70. The thermocompression operation softens the adhesive toner applied in advance by the printer unit 1, and the adhesive toner, which is the toner for adhesion, melts to form an adhesive layer S (see FIG. 5(b)), and the sheets are adhered to each other by the adhesive layer S. Hereinafter, the adhesive toner Tn that is heated and melted by the pressure plate 62 and then cooled is referred to as the adhesive layer S (adhesive). In this embodiment, the amount of adhesive toner Tn applied to the sheet P is 0.9 mg / cm. 2 The specific gravity of the adhesive toner Tn is about 1.0 g / cm 3 A level of this is used.

[0085] The booklet making device 50 of the present embodiment makes a booklet containing more than a predetermined number of sheets as a product by performing one thermocompression bonding operation in the thermocompression bonding unit 60 every time a predetermined number of sheets P are stacked. That is, the thermocompression bonding unit 60 performs the next thermocompression bonding operation in a state where the subsequent sheets are stacked on the sheet bundle already bonded in the previous thermocompression bonding operation, thereby bonding the surface (first surface) of the top sheet of the bonded sheet bundle and the surface (second surface) of the subsequent sheet facing the first surface. This allows the thermocompression bonding unit 60 to make a booklet with a number of sheets greater than the number of sheets that can be bonded in one thermocompression bonding operation. In other words, the pressure plate 62 heats and presses the first sheet bundle, and then heats and presses the second sheet bundle placed on the first sheet bundle, thereby bonding the first sheet bundle and the second sheet bundle to form one booklet.

[0086] The number of sheets P that the thermocompression bonding unit 60 thermocompresses in one thermocompression bonding operation (predetermined number) can be changed as appropriate, taking into consideration the time required for the thermocompression bonding process and the productivity of booklet production. The thermocompression bonding unit 60 may be configured to perform one thermocompression bonding operation every time one subsequent sheet is stacked on the bonded sheet stack. In the following description, it is assumed that the thermocompression bonding unit 60 performs one thermocompression bonding operation every time five sheets P are stacked on the intermediate stacking section 51.

[0087] For example, a booklet consisting of 15 sheets P is produced by the following process. The first thermocompression bonding operation is performed when the first to fifth sheets P are stacked on the intermediate stacker 51 and aligned by the alignment mechanism. By the first thermocompression bonding operation, a bonded sheet stack including five sheets P (hereinafter, referred to as a five-sheet temporary booklet) is produced. The second thermocompression bonding operation is performed when the sixth to tenth sheets P are stacked on top of the five-sheet temporary booklet and aligned by the alignment mechanism. By the second thermocompression bonding operation, a bonded sheet stack including ten sheets P (hereinafter referred to as a ten-sheet temporary booklet) is produced. The third thermocompression bonding operation is performed when the 11th to 15th sheets P are stacked on top of the 10-sheet temporary booklet and aligned by the alignment mechanism. A bonded sheet stack containing 15 sheets P (hereinafter referred to as a 15-sheet temporary booklet) is produced by the third thermocompression bonding operation. A booklet containing 15 sheets P is completed as an end product by the above three thermocompression bonding operations.

[0088] When the number of sheets P that have been stacked in advance in the buffer mechanism (stacking section) are transported to the booklet production device 50, the number of sheets P stacked by the buffer mechanism (stacking section) is set to be the same as the number of sheets P that the thermocompression bonding unit 60 thermocompresses in one thermocompression bonding operation. This makes it possible to shorten the time required to complete alignment of a predetermined number of sheets P compared to when the booklet production device 50 aligns a predetermined number of sheets P that are transported one by one, and therefore may shorten the interval between thermocompression bonding operations. This also makes it possible to improve the productivity of the post-processing device 4 as a whole.

[0089] Furthermore, when the number of sheets included in one booklet is less than a predetermined number, the thermocompression operation may be performed when all sheets P included in one booklet are stacked on the intermediate stacker 51 and aligned by the alignment mechanism.

[0090] The booklet produced by the thermocompression operation of the thermocompression unit 60 is pushed toward the booklet discharge port 40 (FIG. 1) by a booklet discharge guide provided in the booklet production device 50. The booklet discharge guide stops after the leading edge of the booklet reaches the booklet discharge roller pair 39, and returns to the standby position. The booklet discharge roller pair 39, which receives the booklet from the booklet discharge guide, discharges the booklet from the post-processing device 4 to the lower discharge tray 34. This completes the series of booklet production operations for producing one booklet.

[0091] [Mechanism of lumps] Next, the mechanism of dents will be described with reference to Fig. 5(a) and (b). Fig. 5(a) is a schematic diagram showing a cross section of a booklet after the booklet production operation is completed according to Comparative Example 1. The number of sheets in the booklet shown in Fig. 5(a) is assumed to be a relatively large number under which dents are likely to occur.

[0092] The lumps are a phenomenon that occurs in the area where the adhesive toner Tn is applied. More specifically, the lumps are a state in which the area where the adhesive toner Tn is applied has a dent in the thickness direction of the sheet P, compared to an area where the adhesive toner Tn is not applied, and the appearance is impaired. The area where the adhesive toner Tn is applied is heated and pressurized by the thermocompression bonding unit 60 as described above. Since the adhesive toner Tn has thermoplasticity, the adhesive toner Tn is put into a molten state by the heat received from the thermocompression bonding unit 60. Furthermore, the adhesive toner Tn in the molten state melts and spreads due to the pressure received from the thermocompression bonding unit 60, and some of it tends to soak into the fine irregularities on the surface of the sheet P.

[0093] This action strengthens the force that holds the sheets P together, and as a result, the distance between the sheets P becomes closer. The thickness of the adhesive layer S formed by the adhesive toner Tn is likely to be thinner than the thickness-wise distance between the sheets P that occurs when the sheets P are normally stacked. This action makes the thickness TH1 of the booklet in the application area AR1 where the adhesive toner Tn is applied thinner than the thickness TH2 of the booklet in the non-application area AR2 where the adhesive toner Tn is not applied. When the difference in thickness becomes large, it becomes apparent as a dent. The inventor's study revealed that the dent is likely to occur when the number of sheets P that form the booklet (hereinafter also referred to as the number of booklets) is large and when the heating and pressing effect of the thermocompression bonding unit 60 is large. The heating and pressing effect of the thermocompression bonding unit 60 is large when the pressure force is large, when the heating temperature is high, and when the heating time is long.

[0094] 5(b) is an enlarged cross-sectional view showing the adhesive layer S sandwiched between the sheets P1 and P2 after the booklet production operation is completed. As described above, the surface of the sheet P has a certain uneven shape. Therefore, when the adhesive toner Tn is subjected to the thermocompression operation by the thermocompression bonding unit 60, the molten adhesive toner Tn enters into the recesses. The degree of penetration of the adhesive toner Tn, that is, the strength of the heat and pressure applied by the thermocompression bonding unit 60, can be evaluated by the thickness W of the adhesive layer S shown in FIG. 5(b).

[0095] In this case, the thickness W of the adhesive layer S after the thermocompression bonding operation was measured under the following conditions. Observation equipment: Field emission scanning electron microscope (S-4800, manufactured by Hitachi High-Tech Corporation) ·Measurement conditions: Magnification 300x Measurement method: The booklet that has been subjected to the booklet production process is cut out to expose the adhesive layer S. After that, the thickness W of the adhesive layer S in the thickness direction of the sheet P is measured. - Averaging method: 20 measurements were taken and the simple average was calculated. Measurement position: The adhesive layer S that was closest to the heating plate 502 during the final thermocompression bonding operation, which tended to have the highest correlation with lumps, was measured. That is, the measured adhesive layer S is formed between the topmost sheet (P1) of the multiple sheets forming the booklet and the sheet (P2) that is adjacent to the topmost sheet (P1) and is arranged below it. In other words, the measured adhesive layer S is the adhesive layer S that is located closest to the pressure plate 62 in the booklet. Booklet production conditions: Red Label Presentation (Canon, A4 size) was used as the sheet P, and the thickness W of the adhesive layer S and the occurrence of lumps were confirmed while changing the number of booklets and the thermocompression operation conditions.

[0096] From the viewpoint of preventing the above-mentioned dents, the inventors have found that in a booklet consisting of, for example, 30 sheets P, which is a relatively large number of sheets, the thickness W of the adhesive layer S is preferably about 8 μm or more, and more preferably about 10 μm or more. Conversely, it has been found that in the case where the thickness of the adhesive layer S is about 5 μm or less, dents will occur when a booklet consisting of 30 or more sheets is produced. For example, from the viewpoint of preventing the occurrence of dents, when the number of sheets P forming the booklet is 30, the thickness W of the adhesive layer S is preferably 6 μm or more and 20 μm or less.

[0097] [Adhesive strength test] Next, a method for evaluating the adhesive strength of the adhesive layer S will be described with reference to Fig. 6(a) and (b). Fig. 6(a) is a diagram showing how the adhesive strength of a booklet made by thermocompression bonding two sheets P is measured. Fig. 6(b) is a diagram showing how the adhesive strength of a booklet made by thermocompression bonding four sheets P is measured.

[0098] In the method of evaluating the adhesive strength, first, the booklet after the thermocompression operation was cut into a width of 20 mm to prepare a test piece. Next, the sheet P of this test piece closest to the pressure plate 62 was held by a holding member 75 arranged above the booklet. Furthermore, all the remaining sheets P of the booklet were held by a holding member 76 arranged below the booklet. That is, the holding member 76 holds the second sheet P in the example of FIG. 6(a), and holds all the second to fourth sheets P in the example of FIG. 6(b). In addition, a digital force gauge M (manufactured by Nidec-Shimpo Corporation, FGP-2) was connected to the holding member 75. The digital force gauge was gradually pulled upward, and the measured value of the digital force gauge was measured when the adhesive part of the adhesive layer S peeled off. The measurement was performed five times, and the average value was taken as the adhesive strength of the adhesive layer S.

[0099] 7 shows the results of the adhesive strength test when the number of booklets was changed, specifically, the results for 2, 3, 4, and 10 booklets. The following conditions for the thermocompression bonding operation by the thermocompression bonding unit 60 were common: pressure: average surface pressure 0.2 MPa, surface temperature of pressure plate 62: 200°C, heating time: 2.0 seconds, sheet P: Red Label Presentation (Canon, A4 size). The heating time is the heating time of the sheet stack by pressure plate 62 in the thermocompression bonding operation.

[0100] As shown in Figure 7, it was confirmed that the adhesive strength of the adhesive layer S tends to become stronger as the number of booklets increases up to 4 pages. It was also confirmed that when the number of booklets is more than 4 pages, the adhesive strength tends to converge to a nearly constant value.

[0101] For example, in the case of a small number of booklets as shown in Fig. 6(a), the adhesive strength test mode is a test mode in which the strength measurement element in the direction of peeling the sheets P from each other perpendicularly to the thickness direction of the sheets P is strong. In this case, it is known that the adhesive toner Tn made of thermoplastic resin used in this embodiment is easily peeled off by a relatively small force due to the adhesive layer S. Therefore, it has been found that the adhesive strength tends to be low.

[0102] On the other hand, for example, as shown in FIG. 6(b), when the number of booklets is large, the adhesive strength test mode is a test mode in which the strength measurement element in the direction of peeling parallel to the thickness direction of the sheet P is strengthened, that is, a test mode for evaluating the shear direction strength of the adhesive layer S. In this case, it is known that the adhesive toner Tn made of thermoplastic resin used in this embodiment tends to obtain a relatively high adhesive strength. This tendency is due to the fact that, when the number of booklets is increased beyond four, the change in the pulling angle of the sheet P is relatively small, and the change in the test mode from the mode for evaluating the strength in the shear direction is small, so that the adhesive strength tends to converge to a certain value.

[0103] Incidentally, the inventors have confirmed through their investigations that the adhesive strength of the adhesive layer S for producing the booklet is desirably 0.3 N / cm or more per unit distance in the width direction of the test piece.

[0104] From the above, it was confirmed that even if booklets are produced under the same heating and pressing conditions, a larger number of booklets can ensure a stronger adhesive strength. In other words, in order to ensure the same adhesive strength as when there are fewer booklets, when there are more booklets, it can be said that it is possible to weaken the conditions of the thermocompression bonding operation by the thermocompression bonding unit 60, that is, to reduce the pressure, heating temperature, and heating time.

[0105] [Thermocompression unit operating conditions and performance evaluation] Next, we will explain the performance evaluation of adhesive strength and lumps when the operating conditions of the thermocompression unit 60 are changed according to the number of booklets. As mentioned above, lumps are likely to occur when the adhesive toner Tn is subjected to relatively strong heat and pressure, and are likely to occur when the number of booklets is large. In addition, the adhesive strength of the booklet tends to be better when the number of booklets is large.

[0106] From the above, the basic idea of ​​this invention is to focus on the number of booklets to be produced, and to reduce the heat and pressure strength when the number of booklets is large compared to when the number of booklets is small, thereby suppressing the occurrence of lumps while maintaining the adhesive strength of the booklets. In this embodiment, a configuration focusing on the pressure during heating and pressing as the heating and pressing conditions which are the operating conditions of the thermocompression bonding unit 60 will be described. The operating conditions of the thermocompression bonding unit 60 are changed by the control unit 90.

[0107] Common conditions for booklet production were that Red Label Presentation (Canon, A4 size) was used as the sheet P, and among the conditions for the thermocompression bonding operation by the thermocompression bonding unit 60, the surface temperature of the pressure plate 62 was 200°C, and the heating time was 2.0 seconds (all other conditions were constant except for the pressure). Furthermore, booklets with 2 and 30 sheets were produced, and when producing the 30-sheet booklet, heating and pressing were performed by the thermocompression bonding unit 60 every 5 sheets as described above. The conditions for each thermocompression operation were as shown in Table 1 below. That is, for example, when producing a booklet with 30 sheets, the thermocompression bonding operation was performed a total of 6 times, and all of the conditions were the same.

[0108] Table 1 shows the booklet production conditions (operating conditions of the thermocompression bonding unit 60) and performance evaluation in this embodiment. The adhesive strength and the thickness W of the adhesive layer S were observed for the adhesive layer S located closest to the pressure plate 62 in the booklet. [Table 1]

[0109] In Comparative Example 1, the number of booklets was relatively small at 2, and the sheet stack was subjected to thermocompression at a relatively high pressure of 0.4 MPa in order to increase the adhesive strength of the booklets. As a result, a high adhesive strength of 0.80 N / cm was achieved, and the adhesive performance was sufficient. In addition, the thickness W of the adhesive layer S was about 5 μm, which is a thickness that would cause lumps, but since the number of booklets was small, the lumps were not apparent and the lumps were not a problem.

[0110] On the other hand, even when the booklet contained a relatively large number of sheets (30 sheets), the thermocompression operation was performed on the sheet stack at 0.4 MP without changing the pressure, which achieved an even higher adhesive strength of 1.4 N / cm, but some lumps occurred.

[0111] Next, the present embodiment will be described. In this configuration, the thermocompression operation was performed at 0.4 MPa as in Comparative Example 1 under the condition of a relatively small number of booklets, 2 sheets. Therefore, the performance evaluation results were also good, with sufficient adhesive strength and no lumps occurring. Under the condition of a relatively large number of booklets, 30 sheets, the pressure condition was changed from 0.4 MPa in Comparative Example 1 to 0.2 MPa. Under this condition, the adhesive strength was 1.2 N / cm, which tended to decrease compared to Comparative Example 1, but still maintained a sufficient adhesive strength. In addition, as for lumps, the pressure condition was changed to a lower direction, so the thickness W of the adhesive layer S was about 10 μm, which was a good condition, and no lumps actually occurred.

[0112] In Comparative Example 2, the number of booklets was relatively small, at 2, and the thermocompression operation was performed at a relatively low pressure of 0.2 MPa. Because the number of booklets was small, the adhesive strength obtained was only 0.21 N / cm, which was insufficient.

[0113] As described above, in this embodiment, the operating conditions of the thermocompression bonding unit 60 are changed between forming a first booklet including a first number of sheets P and forming a second booklet including a second number of sheets P that is greater than the first number. Specifically, when forming a first booklet (e.g., a booklet with two sheets), the thermocompression bonding unit 60 operates under a first operating condition so that the thickness W of the adhesive layer S located in the first booklet closest to the pressure plate 62 becomes a first thickness. Also, when forming a second booklet (e.g., a booklet with two sheets), the thermocompression bonding unit 60 operates under a second operating condition so that the thickness W of the adhesive layer S located in the second booklet closest to the pressure plate 62 becomes a second thickness that is thicker than the first thickness. In this embodiment, the first operating condition includes the pressure plate 62 pressing the first number of sheets P (e.g., two sheets) with a first pressure (e.g., 0.4 Mpa). The second operating condition includes pressing a second number of sheets (eg, 30) greater than the first number with a second pressure (eg, 0.2 Mpa) less than the first pressure.

[0114] As a result, the thickness of the adhesive layer S formed on the second booklet becomes thicker than the thickness of the adhesive layer S formed on the first booklet, and the occurrence of lumps can be suppressed. This makes it possible to provide a finished product such as a high-quality booklet. Furthermore, since the adhesive strength required for the adhesive layer S is smaller when the number of booklets is greater, even if the pressure applied by the pressure plate 62 when forming the second booklet is the second pressure, which is relatively small, the adhesive strength of the adhesive layer S can be maintained sufficient to form the booklet.

[0115] <Second embodiment> Next, a second embodiment of the present invention will be described, in which the surface temperature of the pressure plate 62 is changed as an operating condition of the thermocompression bonding unit 60 that is changed according to the number of booklets. Therefore, the same configuration as the first embodiment will be described with the same reference numerals in the drawings or omitted from the illustrations.

[0116] In this embodiment, a configuration focusing on the surface temperature (heating temperature) of the pressure plate 62 during heating and pressing as the heating and pressing conditions, which are the operating conditions of the thermocompression unit 60, will be described. As common conditions for booklet production according to the second embodiment, Red Label Presentation (Canon, A4 size) was used as the sheet P, and among the conditions for the thermocompression operation by the thermocompression unit 60, the pressure of the pressure plate 62 was 0.2 Mpa and the heating time was 2.0 seconds (other than the surface temperature of the pressure plate 62 was constant). Furthermore, booklets with 2 and 30 sheets were produced, and when producing the 30-sheet booklet, heating and pressing were performed by the thermocompression unit 60 every 5 sheets as described above. In addition, the conditions for each thermocompression operation were as shown in Table 1 described later. That is, for example, when producing a booklet with 30 sheets, the thermocompression operation was performed a total of 6 times, and all the conditions at that time were the same.

[0117] Table 2 shows the booklet production conditions (operating conditions of the thermocompression unit 60) and performance evaluation in this embodiment. In the second embodiment, the heating temperature of the pressure plate 62, i.e., the surface temperature when the pressure plate 62 heats and presses the sheet stack, was changed according to the number of booklets. The adhesive strength and thickness W of the adhesive layer S were observed for the adhesive layer S located closest to the pressure plate 62 in the booklet. [Table 2]

[0118] In Comparative Example 3, the number of booklets was relatively small at 2, and the sheet stack was subjected to thermocompression bonding at a relatively high heating temperature of 220°C in order to increase the adhesive strength of the booklets. As a result, a high adhesive strength of 0.80 N / cm was achieved, and the adhesive performance was sufficient. In addition, the thickness W of the adhesive layer S was about 5 μm, which is a thickness that would cause lumps, but since the number of booklets was small, the lumps were not apparent and the lumps were not a problem.

[0119] On the other hand, even when the booklet contained a relatively large number of sheets (30 sheets), the heat bonding operation was performed on the sheet stack at 220°C without changing the heating temperature, which achieved an even higher adhesive strength of 1.4 N / cm, but caused bumps to form.

[0120] Next, the present embodiment will be described. In this configuration, the thermocompression bonding operation was performed at 220°C as in Comparative Example 3 under the condition of a relatively small number of booklets, 2 sheets. Therefore, the performance evaluation results were also good, with sufficient adhesive strength and no lumps occurring. Under the condition of a relatively large number of booklets, 30 sheets, the heating temperature condition was changed from 220°C in Comparative Example 3 to 200°C. Under this condition, the adhesive strength was 1.2 N / cm, which tended to decrease compared to Comparative Example 3, but still maintained sufficient adhesive strength. In addition, as for lumps, the heating temperature condition was changed to a lower direction, so the thickness W of the adhesive layer S was about 10 μm, which was a good condition, and no lumps actually occurred.

[0121] As described above, in this embodiment, the operating conditions of the thermocompression bonding unit 60 are changed between forming a first booklet including a first number of sheets P and forming a second booklet including a second number of sheets P that is greater than the first number. Specifically, when forming a first booklet (e.g., a booklet with two sheets), the thermocompression bonding unit 60 operates under a first operating condition so that the thickness W of the adhesive layer S located in the first booklet closest to the pressure plate 62 becomes a first thickness. Also, when forming a second booklet (e.g., a booklet with two sheets), the thermocompression bonding unit 60 operates under a second operating condition so that the thickness W of the adhesive layer S located in the second booklet closest to the pressure plate 62 becomes a second thickness that is thicker than the first thickness. In this embodiment, the first operating condition includes that the surface temperature of the pressure plate 62 is a first temperature (e.g., 220°C). The second operating condition includes the surface temperature of the pressure plate 62 being at a second temperature (eg, 200° C.) lower than the first temperature.

[0122] As a result, the thickness of the adhesive layer S formed on the second booklet becomes thicker than the thickness of the adhesive layer S formed on the first booklet, and the occurrence of lumps can be suppressed. This makes it possible to provide a finished product such as a high-quality booklet. Furthermore, since the adhesive strength required for the adhesive layer S is smaller when the number of booklets is greater, the adhesive strength of the adhesive layer S can be maintained sufficient to form the booklet even when the surface temperature of the pressure plate 62 when forming the second booklet is at a relatively low second temperature.

[0123] <Third embodiment> Next, a second embodiment of the present invention will be described, but in the third embodiment, the heating time of the sheet stack by the pressure plate 62 is changed as an operating condition of the thermocompression bonding unit 60 that is changed according to the number of booklets. Therefore, the same configuration as the first embodiment will be described by omitting illustrations or by assigning the same reference numerals in the drawings.

[0124] In this embodiment, a configuration focusing on the heating time of the pressure plate 62 during heating and pressing as the heating and pressing conditions which are the operating conditions of the thermocompression unit 60 will be described. As common conditions for booklet production according to the third embodiment, Red Label Presentation (Canon, A4 size) was used as the sheet P, and among the conditions for the thermocompression operation by the thermocompression unit 60, the pressure of the pressure plate 62 was 0.2 Mpa and the surface temperature of the pressure plate 62 was 200°C (other than the heating time of the pressure plate 62, all were constant). Furthermore, booklets with two and 30 sheets were produced, and when producing the 30-sheet booklet, heating and pressing were performed by the thermocompression unit 60 every 5 sheets as described above. Moreover, the conditions for each thermocompression operation were as shown in Table 1 described later. That is, for example, when producing a booklet with 30 sheets, the thermocompression operation was performed a total of six times, and all the conditions at that time were the same.

[0125] Table 3 shows the booklet production conditions (operating conditions of the thermocompression unit 60) and performance evaluation in this embodiment. In the third embodiment, the heating time of the pressure plate 62, i.e., the time when the pressure plate 62 heats and presses the sheet stack in one thermocompression operation, was changed according to the number of booklets. The adhesive strength and thickness W of the adhesive layer S were observed for the adhesive layer S located closest to the pressure plate 62 in the booklet. [Table 3]

[0126] In Comparative Example 4, the number of booklets was relatively small at 2, and the sheet stack was subjected to thermocompression bonding for a relatively long heating time of 3.0 seconds in order to increase the adhesive strength of the booklets. As a result, a high adhesive strength of 0.80 N / cm was achieved, and the adhesive performance was sufficient. In addition, the thickness W of the adhesive layer S was about 5 μm, which is a thickness that would cause lumps, but since the number of booklets was small, the lumps were not apparent and the lumps were not a problem.

[0127] On the other hand, even when the number of booklets was relatively high at 30, the heating time was left unchanged at 3.0 seconds, which achieved a higher adhesive strength of 1.4 N / cm, but bumps occurred.

[0128] Next, the present embodiment will be described. In this configuration, under the condition of a relatively small number of booklets, 2, the heating time was set to 3.0 seconds, as in Comparative Example 4. Therefore, the performance evaluation results showed that the adhesive strength was sufficient and no lumps occurred, resulting in good results. Under the condition of a relatively large number of booklets, 30, the heating time condition was changed from 3.0 seconds in Comparative Example 4 to 2.0 seconds. Under this condition, the adhesive strength was 1.2 N / cm, which tended to decrease compared to Comparative Example 4, but still maintained a sufficient adhesive strength. In addition, as for lumps, the heating temperature condition was changed to a lowering direction, so that the thickness W of the adhesive layer S was in a good state of about 10 μm, and no lumps actually occurred.

[0129] As described above, in this embodiment, the operating conditions of the thermocompression bonding unit 60 are changed between forming a first booklet including a first number of sheets P and forming a second booklet including a second number of sheets P that is greater than the first number. Specifically, when forming a first booklet (e.g., a booklet with two sheets), the thermocompression bonding unit 60 operates under a first operating condition so that the thickness W of the adhesive layer S located in the first booklet closest to the pressure plate 62 becomes a first thickness. Also, when forming a second booklet (e.g., a booklet with two sheets), the thermocompression bonding unit 60 operates under a second operating condition so that the thickness W of the adhesive layer S located in the second booklet closest to the pressure plate 62 becomes a second thickness that is thicker than the first thickness. In this embodiment, the first operating condition includes the pressure plate 62 pressing the first number of sheets P (e.g., two sheets) for a first time (e.g., 3.0 seconds). The second operating condition includes pressing a second number of sheets (eg, 30) greater than the first number for a second time period (eg, 2.0 seconds) less than the first time period.

[0130] As a result, the thickness of the adhesive layer S formed on the second booklet becomes thicker than the thickness of the adhesive layer S formed on the first booklet, and the occurrence of lumps can be suppressed. This makes it possible to provide a finished product such as a high-quality booklet. Furthermore, since the adhesive strength required for the adhesive layer S is smaller when the number of booklets is greater, the adhesive strength of the adhesive layer S sufficient for forming the booklet can be maintained even if the heating time of the pressure plate 62 when forming the second booklet is set to the relatively short second time.

[0131] <Fourth embodiment> Next, a fourth embodiment of the present invention will be described, in which the layout of the post-processing device is changed from that of the image forming apparatus 1S of the first embodiment. Therefore, the same configuration as that of the first embodiment will be described by omitting illustrations or by assigning the same reference numerals in the drawings.

[0132] 8, an image forming apparatus 2S according to the fourth embodiment includes a printer unit 1 and a post-processing device 401. The post-processing device 401 is disposed above the printer unit 1, and includes a booklet producing device 50. The booklet producing device 50 includes a thermocompression bonding unit 60.

[0133] As described above, by disposing the post-processing device 401 above the printer unit 1, the intermediate conveying unit 26 of the first embodiment can be omitted, leading to cost reduction. In addition, the installation space required for installing the image forming device 2S can be reduced.

[0134] <Other embodiments> In any of the above-described embodiments, when a booklet having 30 sheets is produced, the thermocompression bonding unit 60 performs a total of six thermocompression bonding operations under the same operating conditions, but this is not limiting. For example, the operating conditions of the thermocompression bonding unit 60 may be changed between the first thermocompression bonding operation and the second and subsequent thermocompression bonding operations.

[0135] In the first to third embodiments, the pressure, heating temperature, and heating time are changed independently according to the number of booklets in order to simplify the description, but the present invention is not limited to this. That is, in order to prevent the occurrence of lumps when the number of booklets is large, any two or more of the above conditions of pressure, heating temperature, and heating time may be changed according to the number of booklets, as long as the thickness of the adhesive layer S is within a certain range. In this case, even if one condition is a condition that increases the strength of the heat and pressure applied by the thermocompression bonding unit 60, the other condition may be a condition that decreases the strength of the heat and pressure applied by the thermocompression bonding unit 60, as long as the thickness of the adhesive layer S is ultimately within a certain range.

[0136] In any of the above-described embodiments, the operating conditions of the thermocompression bonding unit 60 are changed by the control unit 90 provided in the post-processing device 4, but the present invention is not limited to this. The operating conditions of the thermocompression bonding unit 60 may be changed by a control unit provided in the printer unit 1 or the intermediate conveyance unit 26, for example, or may be changed by receiving a signal from an external computer or the like connected to the image forming apparatuses 1S, 2S.

[0137] The present invention can also be realized by a process in which a program for implementing one or more of the functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. The present invention can also be realized by a circuit (e.g., ASIC) that implements one or more of the functions.

[0138] The disclosure of the present embodiment also includes the following configuration examples and method examples. (Configuration 1) In a booklet forming apparatus for forming a booklet by bonding a plurality of sheets, a sheet supporting section for supporting a sheet on which an adhesive toner is applied; an adhesive unit having a pressure member, the pressure member applying heat and pressure to the sheet supported by the sheet support section to melt the adhesive toner and form an adhesive layer, and the sheets are adhered to each other by the adhesive layer; The adhesive unit includes: When forming a first booklet including a first number of sheets, the adhesive layer is operated under a first operating condition so that a thickness of the adhesive layer at a position of the first booklet closest to the pressing member becomes a first thickness; When forming a second booklet including a second number of sheets that is greater than the first number of sheets, the apparatus operates under a second operating condition different from the first operating condition so that a thickness of the adhesive layer at a position in the second booklet closest to the pressing member becomes a second thickness that is greater than the first thickness. A booklet forming apparatus comprising: (Configuration 2) the first operating condition includes the pressure member pressing the first number of sheets with a first pressure; the second operating condition includes the pressure member pressing the second number of sheets with a second pressure less than the first pressure. 2. The booklet forming apparatus according to claim 1, (Configuration 3) the first operating condition includes a surface temperature of the pressure member being a first temperature; the second operating condition includes a surface temperature of the pressure member being a second temperature lower than the first temperature; 2. The booklet forming apparatus according to claim 1, (Configuration 4) The bonding unit has a heater that heats the pressure member. 4. The booklet forming apparatus according to configuration 3. (Configuration 5) the first operating condition includes the pressure member applying heat and pressure to the first number of sheets for a first time; the second operating condition includes the pressure member applying heat and pressure to the second number of sheets for a second time period that is shorter than the first time period. 2. The booklet forming apparatus according to claim 1, (Configuration 6) In a booklet forming apparatus for forming a booklet by bonding a plurality of sheets, a sheet supporting section for supporting a sheet on which an adhesive toner is applied; an adhesive unit having a pressure member, the pressure member applying heat and pressure to the sheet supported by the sheet support section to melt the adhesive toner and form an adhesive layer, and the sheets are adhered to each other by the adhesive layer; The pressure member is forming a first booklet including a first number of sheets, pressing the first number of sheets with a first pressure; When forming a second booklet including a second number of sheets that is greater than the first number of sheets, pressing the second number of sheets with a second pressure that is less than the first pressure. A booklet forming apparatus comprising: (Configuration 7) In a booklet forming apparatus for forming a booklet by bonding a plurality of sheets, a sheet supporting section for supporting a sheet on which an adhesive toner is applied; an adhesive unit having a pressure member, the pressure member applying heat and pressure to the sheet supported by the sheet support section to melt the adhesive toner and form an adhesive layer, and the sheets are adhered to each other by the adhesive layer; The surface temperature of the pressure member is a first temperature is set when forming a first booklet having a first number of sheets; When forming a second booklet including a second number of sheets that is greater than the first number of sheets, a second temperature is set lower than the first temperature. A booklet forming apparatus comprising: (Configuration 8) In a booklet forming apparatus for forming a booklet by bonding a plurality of sheets, a sheet supporting section for supporting a sheet on which an adhesive toner is applied; an adhesive unit having a pressure member, the pressure member applying heat and pressure to the sheet supported by the sheet support section to melt the adhesive toner and form an adhesive layer, and the sheets are adhered to each other by the adhesive layer; The pressure member is applying heat and pressure to the first number of sheets for a first time period when forming a first booklet including the first number of sheets; When forming a second booklet including a second number of sheets that is greater than the first number of sheets, the second number of sheets are heated and pressed for a second time period that is shorter than the first time period. A booklet forming apparatus comprising: (Configuration 9) the pressing member heats and presses the first sheet stack, and then heats and presses the second sheet stack placed on the first sheet stack, thereby bonding the first sheet stack and the second sheet stack to form one booklet. 9. The booklet forming apparatus according to any one of configurations 1 to 8, (Configuration 10) The bonding unit operates so that the adhesive strength between the sheets forming the booklet is 0.3 N / cm or more. 9. The booklet forming apparatus according to any one of configurations 1 to 8, (Configuration 11) an image forming section for forming an image on a sheet and applying the adhesive toner to the sheet; A booklet forming apparatus according to any one of configurations 1 to 8, 1. An image forming apparatus comprising: (Configuration 12) the image forming unit forms an adhesive toner image in an adhesive region on the sheet by using the adhesive toner, and forms an image in an image region on the sheet different from the adhesive region by using the image forming toner; 12. The image forming apparatus according to claim 11, [Explanation of symbols]

[0139] 1S, 2S: image forming device / 1e: image forming section (image forming unit) / 50: booklet forming device (booklet making device) / 51: sheet support section (intermediate stacking section) / 60: adhesive unit (thermocompression unit) / 62: pressure member (pressure plate) / 70: heater / P: sheet / S: adhesive layer / Tn: toner for adhesion (adhesive toner) / W: thickness

Claims

1. In a booklet forming apparatus for forming a booklet by bonding a plurality of sheets, a sheet supporting section for supporting a sheet on which an adhesive toner is applied; an adhesive unit having a pressure member, the pressure member applying heat and pressure to the sheet supported by the sheet support section to melt the adhesive toner and form an adhesive layer, and the sheets are adhered to each other by the adhesive layer; The adhesive unit includes: When forming a first booklet including a first number of sheets, the adhesive layer is operated under a first operating condition so that the thickness of the adhesive layer at a position in the first booklet closest to the pressing member becomes a first thickness; When forming a second booklet including a second number of sheets that is greater than the first number of sheets, the apparatus operates under a second operating condition different from the first operating condition such that a thickness of the adhesive layer at a position in the second booklet closest to the pressing member becomes a second thickness that is greater than the first thickness. A booklet forming apparatus comprising:

2. the first operating condition includes the pressure member pressing the first number of sheets with a first pressure; the second operating condition includes the pressure member pressing the second number of sheets with a second pressure less than the first pressure.

2. The booklet forming apparatus according to claim 1.

3. the first operating condition includes a surface temperature of the pressure member being a first temperature; the second operating condition includes a surface temperature of the pressure member being a second temperature lower than the first temperature; 2. The booklet forming apparatus according to claim 1.

4. The bonding unit has a heater that heats the pressure member.

4. The booklet forming apparatus according to claim 3.

5. the first operating condition includes the pressure member applying heat and pressure to the first number of sheets for a first time; the second operating condition includes the pressure member applying heat and pressure to the second number of sheets for a second time period that is shorter than the first time period.

2. The booklet forming apparatus according to claim 1.

6. In a booklet forming apparatus for forming a booklet by bonding a plurality of sheets, a sheet supporting section for supporting a sheet on which an adhesive toner is applied; an adhesive unit having a pressure member, the pressure member applying heat and pressure to the sheet supported by the sheet support section to melt the adhesive toner and form an adhesive layer, and the sheets are adhered to each other by the adhesive layer; The pressure member is forming a first booklet including a first number of sheets, pressing the first number of sheets with a first pressure; When forming a second booklet including a second number of sheets that is greater than the first number of sheets, pressing the second number of sheets with a second pressure that is less than the first pressure. A booklet forming apparatus comprising:

7. In a booklet forming apparatus for forming a booklet by bonding a plurality of sheets, a sheet supporting section for supporting a sheet on which an adhesive toner is applied; an adhesive unit having a pressure member, the pressure member applying heat and pressure to the sheet supported by the sheet support section to melt the adhesive toner and form an adhesive layer, and the sheets are adhered to each other by the adhesive layer; The surface temperature of the pressure member is a first temperature is set when forming a first booklet having a first number of sheets; When forming a second booklet including a second number of sheets, the second number being greater than the first number of sheets, the temperature is set to a second temperature lower than the first temperature. A booklet forming apparatus comprising:

8. In a booklet forming apparatus for forming a booklet by bonding a plurality of sheets, a sheet supporting section for supporting a sheet on which an adhesive toner is applied; an adhesive unit having a pressure member, the pressure member applying heat and pressure to the sheet supported by the sheet support section to melt the adhesive toner and form an adhesive layer, and the sheets are adhered to each other by the adhesive layer; The pressure member is When forming a first booklet including a first number of sheets, applying heat and pressure to the first number of sheets for a first time; When forming a second booklet including a second number of sheets that is greater than the first number of sheets, the second number of sheets are heated and pressed for a second time period that is shorter than the first time period. A booklet forming apparatus comprising:

9. the pressing member heats and presses a first sheet bundle, and then heats and presses a second sheet bundle placed on the first sheet bundle, thereby bonding the first sheet bundle and the second sheet bundle to form one booklet.

9. The booklet forming apparatus according to claim 1, wherein the first and second sheets are arranged in a first direction.

10. The bonding unit operates so that the adhesive strength between the sheets forming the booklet is 0.3 N / cm or more.

9. The booklet forming apparatus according to claim 1, wherein the first and second sheets are arranged in a first direction.

11. an image forming section for forming an image on a sheet and applying the adhesive toner to the sheet; The booklet forming apparatus according to any one of claims 1 to 8, 1. An image forming apparatus comprising:

12. the image forming unit forms an adhesive toner image in an adhesive region on the sheet by using the adhesive toner, and forms an image in an image region on the sheet different from the adhesive region by using the image forming toner; 12. The image forming apparatus according to claim 11.

Images