Sheet adhesive device

Abstract

To provide a sheet adhesive device capable of realizing stable adhesive strength regardless of the printing rate of preprinted paper.SOLUTION: Control means controls an application unit to increase an amount of adhesive applied as the printing rate of an image printed on a sheet increases.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a sheet bonding apparatus that bonds sheets with a powder adhesive by utilizing an application unit that applies adhesive to the sheets. [Background technology]

[0002] When creating documents that need to be sealed because the contents are confidential, such as pay slips or sealed postcards, an image forming device has been proposed that outputs a finished product in which the confidential information is sealed by folding a sheet and gluing it with a powder adhesive, as in Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-193004 A Summary of the Invention [Problem to be solved by the invention]

[0004] When creating a sealed product as in Patent Document 1, it is conceivable to use preprinted paper (hereinafter referred to as preprinted paper) on which information has been printed beforehand as the sheet to be adhesively processed. In this case, there is a concern that preprinted paper using electrophotographic toner may have insufficient adhesive strength in areas with a high printing rate. This is because the melted toner covers the paper fibers of the sheet, preventing the powder adhesive applied on the toner from penetrating the gaps between the paper fibers and thus failing to exert a sufficient anchoring effect. This leads to insufficient adhesive strength, and there is a concern that poor adhesion of the sheet may occur. The present invention aims to achieve stable adhesive strength regardless of the printing rate of the preprinted paper. [Means for solving the problem]

[0005] The present invention is a sheet bonding device comprising an application unit which applies adhesive to a sheet, a folding means which folds the sheet to which the adhesive has been applied with the surface to which the adhesive has been applied facing inward, a bonding means which heats and / or pressurizes the sheet folded by the folding means to bond the sheet with adhesive, and a control means which controls the amount of adhesive applied by the application unit based on printing information of an image printed on the sheet before the adhesive is applied, characterized in that the control means controls the application unit so that the amount of adhesive applied increases as the printing rate of the image printed on the sheet increases. Effect of the Invention

[0006] According to the present invention, a sheet bonding device capable of realizing a stable adhesive force regardless of the printing rate of the preprinted paper is provided. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic view of a sheet bonding apparatus according to a first embodiment. [Diagram 2] FIG. 2 is a schematic view of a process cartridge according to the first embodiment. [Diagram 3] FIG. 4 is a diagram for explaining the contents of a folding process according to the first embodiment. [Figure 4] FIG. 4 is a diagram for explaining the relationship between the printing rate of the preprinted paper and the amount of powder adhesive applied in the first embodiment. [Diagram 5] FIG. 11 is a diagram for explaining the relationship between the printing rate of the preprinted paper and the amount of powder adhesive applied in the modified example of the first embodiment. [Figure 6] FIG. 4 is a diagram for explaining the relationship between the amount of powder adhesive applied and adhesive strength in Example 1. [Figure 7] FIG. 10 is a diagram for explaining a case where a reading means for a preprint paper according to the second embodiment is another device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. EXAMPLES

[0009] (Overall device configuration) First, the overall configuration of the sheet bonding device 1a will be described with reference to Fig. 1. Fig. 1 is a schematic diagram showing a cross-sectional configuration of the sheet bonding device 1a including a sheet bonding device main body (hereinafter referred to as device main body 10) according to the first embodiment and a post-processing unit 30 connected to the device main body 10. The sheet bonding device 1a is composed of the device main body 10 including an electrophotographic powder adhesive application mechanism and the post-processing unit 30 as a sheet processing device. As will be described below, the device main body 10 has a similar configuration to an electrophotographic image forming device, except that a powder adhesive is used as a developer.

[0010] First, the internal configuration of the device main body 10 will be described. As shown in FIG. 1, the device main body 10 includes a sheet cassette 8 as a sheet storage section for storing the sheet P to be bonded, an electrophotographic unit G1 for applying a powder adhesive to the sheet P, a fixing device 6 as a fixing means (first heating device), and a housing 19 for accommodating these components. The device main body 10 has a function of applying a powder adhesive Tn to the sheet P fed from the sheet cassette 8 by the electrophotographic unit G1, and performing a fixing process in which the powder adhesive Tn is fixed to the sheet P by the fixing device 6. Here, as the sheet P, a preprinted paper on which information is printed in advance by various printing methods such as an electrophotographic method, an inkjet method, and an offset printing method is set. The sheet bonding device 1a of this embodiment is a device that applies only the powder adhesive Tn to the preprinted paper to create a bonded product, and can also be called a pressure bonding device.

[0011] The sheet cassette 8 is inserted into the housing 19 at the bottom of the device main body 10 so as to be removable, and stores a large number of sheets P. The sheets P stored in the sheet cassette 8 are fed from the sheet cassette 8 by the feed roller 8f, and are separated one by one by a pair of separation rollers (not shown), and then transported by the transport roller 8a. The feed roller 8f is an example of a feeding member that feeds the sheets P, and may be a feeding mechanism that adsorbs the sheets P to the surface of an endless belt having air holes formed thereon by a negative pressure generated by an air suction unit and transports the sheets. The pair of separation rollers includes a conveying roller that conveys the sheets P, and a separation roller that is supported by a fixed shaft via a torque limiter and abuts against the conveying roller. In a nip portion (separation nip) between the conveying roller and the separation roller, the separation roller applies a frictional force to the sheets, thereby preventing sheets other than the sheet P in contact with the conveying roller from being fed in multiple. The mechanism for separating the sheets P is not limited to the separation roller, and may be, for example, a pad-shaped friction member.

[0012] The preprint paper reading device (hereinafter simply referred to as "reading device 200") is disposed above the transport roller 8a, and functions as a means for reading information printed on the preprint paper as image data and sending it to an image generating section (not shown). The reading device 200 incorporates a CIS (Contact Image Sensor) sensor, and for example, photodiodes for 10368 pixels are arranged in an array at a specific main scanning density (for example, 1200 dpi). In addition to the CIS sensor, it is also possible to replace it with a CMOS sensor, CCD sensor, etc.

[0013] The electrophotographic unit G1 is an electrophotographic mechanism including a process cartridge P1, a scanner unit 2, and a transfer roller 3. The electrophotographic unit G1 functions as an adhesive application unit that applies a powder adhesive to a sheet P by an electrophotographic process using a powder adhesive as a developer. A process cartridge is a unit in which a plurality of parts that are responsible for the electrophotographic process are integrated into one unit so as to be replaceable. The apparatus main body 10 is provided with a cartridge support portion (not shown) that is supported by a housing 19, and the process cartridge P1 is detachably mounted in the apparatus main body 10.

[0014] The process cartridge P1 is composed of a photosensitive unit CC equipped with a photosensitive drum 101 as an image carrier, a powder container 104, and a developing unit DT equipped with a developing roller 105 for performing development using powder. Details will be described later. In this disclosure, the term "development" is not limited to the process of visualizing an electrostatic latent image on an image carrier using a printing toner (colored toner), but is also used for the process of adhering a transparent powder adhesive Tn to the electrostatic latent image on the image carrier. The powder container 104 contains a powder adhesive Tn (powder adhesive, adhesive toner) which is a powder for performing an adhesion process on the sheet P.

[0015] The scanner unit 2 functions as an exposure unit that irradiates the photosensitive drum 101 of the process cartridge P1 with a laser beam Z to write an electrostatic latent image. The transfer roller 3 faces the photosensitive drum 101 of the process cartridge P1 and forms a transfer nip 3n as a transfer section together with the photosensitive drum 101. The transfer roller 3 functions as a transfer unit that transfers the powder adhesive Tn from the photosensitive drum 101 to the sheet P fed from the sheet cassette 8 in the transfer nip 3n.

[0016] The fixing device 6 is disposed above the transfer roller 3. The fixing device 6 is a fixing device of a thermal fixing type having a heating roller 6a as a fixing member and a pressure roller 6b as a pressure member. The heating roller 6a is heated by a heating element such as a halogen lamp or a ceramic heater or a heating mechanism of an induction heating type. The pressure roller 6b is pressed against the heating roller 6a by a biasing member such as a spring, and generates a pressure force for pressing the sheet P passing through the nip portion (fixing nip 6n) between the heating roller 6a and the pressure roller 6b. Note that, although a configuration in which a pair of rollers as a pair of rotating bodies sandwich and transport a sheet has been exemplified here, for example, a fixing device of a thermal film type may be used as the fixing device 6. The thermal film type fixing device has a cylindrical film with a heater having a resistance heating element disposed inside, and a pressure roller pressed against the heater with the film sandwiched therebetween, and transports the sheet by sandwiching it in the nip portion between the pressure roller and the film.

[0017] The housing 19 is provided with a discharge port 12, which is an opening for discharging the sheet P from the apparatus body 10, and a discharge unit 34 is disposed in the discharge port 12. The discharge unit 34, which is the discharge means in this embodiment, has a first discharge roller 34a and a second discharge roller 34b.

[0018] In addition, the conveying path passing through the conveying roller 8a, the transfer nip 3n, and the fixing nip 6n in the device body 10 constitutes a main conveying path R0 along which the powder adhesive Tn is applied (transferred) to the sheet P. When viewed from the main scanning direction in the electrophotographic process, the main conveying path R0 extends from below to above passing one side of the horizontal direction H with respect to the electrophotographic unit G1. Here, the main scanning direction is the direction of the rotation axis of the photosensitive drum 101, and is also the sheet width direction perpendicular to the conveying direction of the sheet P conveyed on the main conveying path R0. In other words, the device body 10 of this embodiment is a so-called vertical conveying type (vertical path type) electrophotographic device in which the main conveying path R0 extends in a substantially vertical direction V. When viewed from the vertical direction V, the intermediate path 15 (described in detail later) and the sheet cassette 8 at least partially overlap each other. Therefore, the movement direction of the sheet P when the discharge unit 34 discharges the sheet P in the horizontal direction H is opposite to the movement direction of the sheet P when the sheet P is fed from the sheet cassette 8 in the horizontal direction H.

[0019] (Aftertreatment Unit) As shown in Fig. 1, the post-processing unit 30 is attached to the upper part of the device body 10. In the post-processing unit 30, a folder 31 as a folding means and an adhesive means 32 as an adhesive means are housed in a housing 39 and integrated together. The post-processing unit 30 is also provided with an intermediate path 15 and a first discharge tray 35. The function of each part of the post-processing unit 30 will be described later.

[0020] (Process cartridge) The process cartridge P1 will now be described in detail. Fig. 2 is a cross-sectional view showing a schematic configuration of the process cartridge P1. The process cartridge P1 is made up of a photosensitive unit CC including a photosensitive drum 101 and the like, and a developing unit DT including a developing roller 105 and the like.

[0021] A photosensitive drum 101, which is an electrophotographic photosensitive member formed into a drum shape, is rotatably attached to the photosensitive unit CC via a bearing (not shown). The photosensitive drum 101 is driven to rotate in a counterclockwise direction (arrow w) in the drawing when an electrophotographic process is performed by receiving a driving force from a motor serving as a driving means (driving source) (not shown) provided in the apparatus main body 10. Furthermore, the photosensitive unit CC is provided with a charging roller 102 as a charging means for charging the photosensitive drum 101 around the photosensitive drum 101, and a cleaning member 103 as a cleaning means for cleaning the surface of the photosensitive drum 101.

[0022] The developing unit DT is provided with a developing roller 105 as a developer carrier that contacts the photosensitive drum 101 and rotates in a clockwise direction (arrow d) in the figure. The developing roller 105 and the photosensitive drum 101 each rotate so that their surfaces move in the same direction at the opposing portion (contact portion). The developing roller 105 functions as a developing means that develops the electrostatic latent image on the photosensitive drum 101 using a powder adhesive Tn as a developer.

[0023] The developing unit DT is also provided with a developer supply roller (hereinafter simply referred to as "supply roller 106") as a developer supply member that rotates in a clockwise direction (arrow e) in the figure. The supply roller 106 and the developing roller 105 each rotate such that their surfaces move in opposite directions at their opposing portions (contact portions). The supply roller 106 supplies powder adhesive Tn onto the developing roller 105. At the same time, the supply roller 106 acts to strip off the powder adhesive remaining on the developing roller 105 from the developing roller 105. The developing unit DT is also provided with a developing blade 107 as a developer regulating member that regulates the layer thickness of the powder adhesive Tn supplied onto the developing roller 105 by the supply roller 106.

[0024] A powder adhesive Tn is stored as a powder in the powder storage unit 104. A rotatably supported transport member 108 is provided in the powder storage unit 104. The transport member 108 rotates in a counterclockwise direction (arrow f) in the figure to agitate the powder adhesive Tn stored in the powder storage unit 104 and transport the powder adhesive Tn to the developing roller 105 and the supply roller 106.

[0025] Here, the photoconductor unit CC and the developing unit DT can be separately formed as a photoconductor unit cartridge and a developing unit cartridge, respectively, which can be detachably attached to the apparatus main body 10. Also, it is possible to configure a powder cartridge that has only the powder storage section 104 and the transport member 108 and is detachably attached to the apparatus main body 10, separate from a process cartridge having a photoconductor and a developer carrier.

[0026] (powder adhesive) The powder adhesive Tn of this embodiment can be a powder containing a thermoplastic resin. The thermoplastic resin is not particularly limited, and examples thereof include 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 included.

[0027] In addition, the powder adhesive 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. Furthermore, the powder adhesive Tn may contain a magnetic material, a charge control agent, and an external additive.

[0028] In order to form an adhesive region (adhesive portion) by the powder adhesive tn on the sheet P by using an electrophotographic method, the weight average particle diameter of the powder adhesive 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. Note that a printing toner may be used as the powder adhesive Tn as long as it satisfies the adhesive property.

[0029] (Sheet adhesion operation) Next, the sheet bonding operation performed by the sheet bonding apparatus 1a of this embodiment will be described with reference to Figures 1, 2, and 3(a to 3f). Figures 3(a to 3f) are diagrams for explaining the contents of the folding process.

[0030] When using the sheet bonding device 1a of this embodiment to create a product such as a pressure-bonded postcard or a pay slip, first, a preprinted sheet on which information has been printed is set as a sheet P in the sheet cassette 8. At this time, the surface of the sheet P to be bonded is set facing upward (upper side of the device).

[0031] First, an instruction to execute the sheet bonding operation is input to the sheet bonding apparatus 1a from an external personal computer or the like. A control unit (not shown) of the sheet bonding apparatus 1a reads information printed on the sheet P as image data using a reading device 200 while conveying the sheet P, and sequentially transmits the image data to the image generating unit. The image generating unit creates an application pattern (described in detail later) of the powder adhesive Tn to be printed based on the received image data, and transmits the pattern to the control unit of the sheet bonding apparatus 1a. Thereafter, the control unit applies the powder adhesive Tn to the sheet P according to the application pattern transmitted while conveying the sheet P, and starts a series of operations (sheet bonding operation) in which the post-processing unit 30 performs folding and bonding processes. In the sheet bonding operation, first, as shown in FIG. 1, the sheets P are fed one by one from a sheet cassette 8 and conveyed toward the transfer nip 3n via a conveying roller 8a.

[0032] In parallel with the feeding of the sheet P, the photosensitive drum 101 of the process cartridge P1 is rotated in a counterclockwise direction (arrow w) in the figure. The surface of the photosensitive drum 101 is uniformly charged by the charging roller 102. In addition, the scanner unit 2 irradiates the photosensitive drum 101 of the process cartridge P1 with a laser beam Z based on a coating pattern to form an electrostatic latent image on the surface of the photosensitive drum 101. Next, the electrostatic latent image on the photosensitive drum 101 is developed into a powder adhesive Tn image by the powder adhesive Tn carried by the developing roller 105 of the process cartridge P1. That is, the powder adhesive Tn adheres to an area on the surface of the photosensitive drum 101 corresponding to the coating pattern in which the powder adhesive Tn is to be applied to the sheet P.

[0033] The powder adhesive Tn image formed on the photosensitive drum 101 is transferred to the sheet P at a transfer nip 3n between the photosensitive drum 101 and the transfer roller 3. This means that the electrophotographic unit G1 applies (transfers) the powder adhesive Tn to the sheet P.

[0034] Thereafter, the sheet P is conveyed to the fixing device 6 and undergoes a thermal fixing process. That is, when the sheet P passes through the fixing nip 6n, the image of the powder adhesive Tn on the sheet P is heated and pressurized, so that the powder adhesive Tn melts and then adheres to the pre-printed surface of the sheet P. Fixation of the powder adhesive Tn refers to the fact that the particles of the powder adhesive Tn held on the sheet P by electrostatic force after transfer melt and then adhere to the surface of the sheet P by heating and pressurization, so that the particles do not easily peel off from the surface of the sheet P even when subjected to a mechanical external force.

[0035] The sheet P discharged from the apparatus body 10 is sandwiched between the first discharge roller 34a and the second discharge roller 34b, and is transported from the discharge port 12 to the first path R1.

[0036] An intermediate path 15 is provided between the fixing device 6 and the folder 31 in the first route R1. The intermediate path 15 is a sheet transport path located between the apparatus main body 10 and the post-processing unit 30. The intermediate path 15 is inclined upward in the vertical direction V toward the folder 31 with respect to the horizontal direction H. Therefore, the first guide roller 31c and the second guide roller 31d at the entrance of the folder 31 are located vertically higher than the first discharge roller 34a and the second discharge roller 34b at the exit of the apparatus main body 10.

[0037] The folder 31 has four rollers, namely, a first guide roller 31c, a second guide roller 31d, a first folding roller 31a, and a second folding roller 31b, and a lead-in portion 31e. The first guide roller 31c and the second guide roller 31d are a pair of guide rollers that sandwich and transport the sheet P received from a transport path (intermediate path 15 in this embodiment) on the upstream side of the folder 31. The first folding roller 31a and the second folding roller 31b are a pair of folding rollers that feed the sheet P while folding it.

[0038] The distance M from the first discharge roller 34a to the first guide roller 31c in the transport direction of the sheet P along the first path R1 is configured to be shorter than the overall length L of the sheet P in the transport direction before folding. In other words, the distance M from the first discharge roller 34a to the first guide roller 31c determines the lower limit of the length in the transport direction of the sheet P that can be processed by the post-processing unit 30. With this configuration, the sheet P is smoothly delivered from the discharge unit 34 to the pair of guide rollers.

[0039] 3(a-f) show each step of the folding process of the sheet P by the folder 31. The folding process is performed by the folder 31 so that the surface to which the powder adhesive Tn is applied faces inward (the surfaces that face each other when folded).

[0040] When performing folding processing, as shown in Fig. 3(a), the first guide roller 31c and the first folding roller 31a rotate in a clockwise direction in the figure, and the second guide roller 31d and the second folding roller 31b rotate in a counterclockwise direction in the figure. First, the leading edge q of the sheet P sent out from the discharge unit 34 is pulled into the pair of guide rollers (31c, 31d). As shown in Fig. 3(b), the leading edge q of the sheet P is guided downward by the guide wall 31f and contacts the first folding roller 31a. Then, the leading edge q is pulled into the first folding roller 31a and the second guide roller 31d, which face each other, and abuts against the wall 31g of the pull-in portion 31e.

[0041] As the guide roller pair (31c, 31d) continues to pull in the sheet P, the leading edge q slides against the wall 31g and advances toward the back of the pull-in section 31e. Eventually, the leading edge q hits the end 31h of the pull-in section 31e as shown in FIG. 3(c). The pull-in section 31e forms a space extending substantially parallel to the intermediate path 15 below the intermediate path 15 as shown in FIG. Then, at the stage shown in FIG. 3(c), the sheet P wraps around the second guide roller 31d and is bent into a U-shape.

[0042] When the sheet P is further drawn in by the guide roller pair (31c, 31d) from the state shown in Fig. 3(c), bending begins to occur at the middle portion r as shown in Fig. 3(d). Eventually, as shown in Fig. 3(e), the middle portion r comes into contact with the second folding roller 31b, and the sheet P is drawn into the nip portion of the folding roller pair (31a, 31b) by the frictional force received from the second folding roller 31b. Then, as shown in Fig. 3(f), the sheet P is folded with the middle portion r as the crease, and is discharged by the folding roller pair (31a, 31b) with the middle portion r at the front.

[0043] In this embodiment, the depth N of the retraction portion 31e (FIG. 3(e)), i.e., the distance from the nip portion of the pair of folding rollers (31a, 31b) to the end portion 31h of the retraction portion 31e, is set to half the total length L of the sheet P. This enables the folder 31 to fold the sheet P in half (center folding). Note that by changing the depth N of the retraction portion 31e, the position of the fold can be changed as desired.

[0044] The folder 31 described above is an example of a folding means, and a folding mechanism may be used that presses a blade against the sheet P and pushes it into the nip between a pair of rollers to form a crease. The folding process is not limited to folding in half, and a folding mechanism that performs Z-folding or three-folding may be used. Since the folder 31 of this embodiment is composed of rotating rollers and a fixed retraction section 31e, the drive mechanism can be simplified compared to a folding mechanism that uses a reciprocating blade. Furthermore, the folder 31 of this embodiment only needs to be provided with a retraction section 31e having a depth N that is half the length L of the sheet P in addition to the four rollers, and therefore the post-processing unit 30 can be made smaller.

[0045] As shown in FIG. 1, the sheet P that has passed through the folding device 31 is conveyed to the adhesive means 32. The adhesive means 32 has a thermal fixing type configuration similar to the fixing device 6. That is, the adhesive means 32 has a heating roller 32b as a heating member and a pressure roller 32a as a pressure member. The heating roller 32b is heated by a heating element such as a halogen lamp or a ceramic heater or a heating mechanism of an induction heating type. The pressure roller 32a is pressed against the heating roller 32b by a biasing member such as a spring, and generates a pressure force for applying pressure to the sheet P that passes through the nip portion (adhesive nip) between the heating roller 32b and the pressure roller 32a. Note that, although the configuration in which the roller pair as the rotating body pair sandwiches and conveys the sheet is exemplified here, for example, a thermal film type fixer (similar to that described for the fixing device 6) may be used as the adhesive means 32. Note that, in this embodiment, by using an adhesive that exerts adhesive force only by pressure, the adhesive means 32 may only apply pressure without providing the heating roller 32b with a heating function.

[0046] The sheet P folded by the folder 31 is subjected to a bonding process (second thermal fixation of the powder adhesive Tn) by the bonding means 32, so that the sheet P is bonded in the folded state. That is, when the sheet P passes through the bonding nip 32n, the powder adhesive Tn on the sheet P is heated and pressurized again in a softened state. This causes the powder adhesives Tn on the bonding surfaces (surfaces where the surfaces coated with the powder adhesive Tn face each other in the folded state) to adhere to each other. Then, the powder adhesive Tn cools and hardens, so that the sheet P is bonded (pressed) using the powder adhesive Tn as an adhesive.

[0047] The sheet P that has been subjected to the bonding process by the bonding means 32 is discharged to the left side in the figure from a discharge port 32c provided in a housing 39 of the post-processing unit 30. Then, the sheet P is stored in a first discharge tray 35 provided on the left side surface of the apparatus main body 10.

[0048] (Method of generating application pattern of powder adhesive) Next, a method for generating a coating pattern of the powder adhesive Tn based on information printed on a preprinted paper will be described with reference to FIG. 4. In this embodiment, a printing rate is calculated from image data, which is printing information read by the reading device 200, and a coating pattern is generated based on this value. The printing rate shown here is the ratio of the cumulative area of ​​characters, etc. to a certain area in the image data. FIG. 4(a) is a diagram showing a low printing rate area A1 and a high printing rate area A2 in a unit pixel (5×5 pixels in this embodiment, resolution is 1200 dpi) on the image data on the sheet P. In the low printing rate area A1, the number of pixels occupied by the character part (filled in part in the figure) is 5 pixels out of the 5×5 pixels shown by the dotted line as in FIG. 4(b), and the printing rate is 20%. On the other hand, in the high printing rate area A2, the number of pixels occupied by the character part is 12 pixels out of the 5×5 pixels as in FIG. 4(c), and the printing rate is about 50%. In such a case, as shown in Fig. 4(b, c), the amount of powder adhesive Tn applied to the low printing rate area A1 is reduced, and the amount of powder adhesive Tn applied to the high printing rate area A2 is increased. For example, the weight of the powder adhesive Tn per unit area in the low printing rate area A1 is set to 0.5 mg / cm 2 The high printing rate area A2 is 0.8 mg / cm 2 It states that:

[0049] As a modified example, an example will be described in which the amount of adhesive applied to the entire paper is changed according to the printing rate of the entire paper.

[0050] As shown in Figures 5(a) and 5(b), when the overall printing rate of the preprinted paper is higher in Figure 5(a) than in Figure 5(b), the amount of adhesive applied to the entire paper is increased in Figure 5(a) compared to Figure 5(b). Note that increasing the amount of adhesive applied only in areas with a high printing rate, as in Figure 4, can reduce the amount of adhesive used compared to increasing the amount of adhesive applied to the entire paper, as in Figure 5.

[0051] Here, the reason for adjusting the application amount of the powder adhesive Tn depending on the printing rate will be explained with reference to Fig. 6. Fig. 6 is a cross-sectional view of a part of the printing area on the sheet P.

[0052] First, the relationship between the adhesive force Fp acting between the powder adhesive Tn and the paper PP constituting the sheet P, and the adhesive force Ft acting between the powder adhesive Tn and the printed toner Tt will be described with reference to FIG. 6(a). The adhesive force Fp is stable because the powder adhesive Tn easily penetrates between the paper fibers due to melting during fixing, providing a sufficient anchoring effect. On the other hand, the adhesive force Ft is weak because the printed toner Tt, which has already melted, covers the spaces between the paper fibers and does not provide a sufficient anchoring effect. At this time, the magnitude relationship between the adhesive forces is Fp>Ft.

[0053] Next, the relationship between the contact area Sp between the powder adhesive Tn and the paper PP and the contact area St between the powder adhesive Tn and the print toner Tt will be described with reference to FIG. 6(b, c, d).

[0054] 6(b) shows the state of the sheet P in the low printing area and the powder adhesive Tn applied thereto. In the low printing area, the amount of printed toner Tt is small, so the contact area Sp is large and the contact area St is small. At this time, the stable adhesive force Fp acts in the contact area Sp, and as a result, the pressure bonding of the preprinted paper is stable in the low printing area where the contact area Sp is large.

[0055] Figure 6(c) shows the state when the sheet P in the high print area and the amount of powder adhesive Tn applied thereto are the same as in the low print area in Figure 6(b). Because the amount of print toner Tt is greater in the high print area, the contact area Sp is smaller than in the low print area, but the contact area St does not increase significantly from that in the low print area. At this time, the contact area Sp over which the stable adhesive force Fp acts decreases, and the contact area St over which the small adhesive force Ft acts does not change significantly, so that with the same amount of powder adhesive Tn as in the low print area, the adhesive force is insufficient for the high print area, and the pressure bonding of the preprinted paper is not stable.

[0056] Therefore, in this embodiment, as shown in Fig. 6(d), the amount of powder adhesive Tn applied to the high print area is made greater than that of the low print area. At this time, although the contact area Sp remains the same as in Fig. 6(c), the contact area St becomes larger. As a result, even if the adhesive force Ft is small, the area over which it acts is large, and as a result, the same contact force can be obtained in the high print area as in the low print area, and the pressure bonding of the preprinted paper becomes stable.

[0057] When the amount of powder adhesive Tn applied is not adjusted according to the printing rate as in this embodiment (when the amount of powder adhesive applied is uniform over the entire surface of the preprinted paper), the amount of powder adhesive Tn required is adjusted to match the high printing area where the adhesive strength is likely to decrease. In this case, an excessive amount of powder adhesive Tn is applied to the low printing area, resulting in unnecessary consumption of the powder adhesive Tn.

[0058] In contrast, in this embodiment, the amount of powder adhesive Tn can be optimized according to the printing rate of the preprinted paper, so the preprinted paper can be stably pressed while suppressing the consumption of powder adhesive Tn. Also, due to the relationship between the SP value of the adhesive and the printed toner, the adhesive force between the printed toner and the sheet is greater than the adhesive force between the adhesive and the printed toner. Therefore, when the folded sheet is peeled off after adhesion, peeling occurs at the interface between the adhesive and the printed toner, and the image can be confirmed without being disturbed. EXAMPLES

[0059] In the first embodiment, a reading device 200 provided in the sheet bonding device 1a is used as a reading means for the preprinted paper. In this embodiment, the application amount of the powder adhesive Tn is controlled using image data, which is print information obtained from a reading means of another device, or image data stored in a personal computer or the like. Examples of the reading means of the other device include an ADF (Auto Document Feeder) of a copy machine and a document scanner. FIG. 7 is a diagram showing a schematic flow of the process in this embodiment. The copy machine 300 functions as a reading means of the other device. A user reads a sheet P, which is preprinted paper, with an ADF (not shown) of the copy machine 300. The sheet bonding device 1a is connected to the copy machine 300 by a communication means 301, and when reading by the ADF is completed, a control unit of the sheet bonding device 1a obtains image data Dp of the sheet P from the copy machine 300. Meanwhile, the user stores the sheet P, which has been read, in the sheet cassette 8 of the sheet bonding device 1a. Thereafter, as in the first embodiment, the application amount of the powder adhesive Tn is controlled according to the printing rate of the sheet P.

[0060] As a result, the application amount of the powder adhesive Tn can be controlled without providing a reading means in the sheet bonding apparatus 1a, which makes it possible to reduce the cost of the apparatus itself.

[0061] [Note] The above embodiment discloses at least the following sheet bonding apparatus.

[0062] (Item 1) an application unit that applies adhesive to the sheet; A folding means for folding the sheet coated with adhesive so that the surface coated with adhesive is inward; an adhesive means for applying heat and / or pressure to the sheet folded by the folding means to adhere the sheet to the sheet by an adhesive; a control means for controlling the amount of adhesive applied by the application unit based on print information of an image printed on the sheet before the adhesive is applied; A sheet bonding apparatus comprising: The sheet bonding apparatus is characterized in that the control means controls the application unit so that the amount of adhesive applied increases as the printing rate of an image printed on the sheet increases.

[0063] (Item 2) The sheet bonding apparatus according to item 1, The control means causes an application amount per unit area of ​​the adhesive applied to an area with a high printing rate in the printed information to be greater than an application amount per unit area of ​​the adhesive applied to an area with a low printing rate in the printed information. A sheet bonding device characterized by:

[0064] (Item 3) The sheet bonding apparatus according to item 1 or 2, The sheet bonding apparatus further comprises a reading means for reading the printed information.

[0065] (Item 4) The sheet bonding apparatus according to items 1 to 3, A sheet bonding apparatus comprising: a communication means for receiving the printed information read by another apparatus.

[0066] (Item 5) The sheet bonding apparatus according to items 1 to 4, The sheet bonding apparatus is characterized in that the application unit applies adhesive to the sheet by utilizing an electrophotographic method. [Explanation of symbols]

[0067] 1a Sheet bonding device (multipurpose device) 6 Fixing means (fixing device) 31 Folding means (folder) 32 Adhesion means 104 Powder container G1 Electrophotographic Unit Tn Powder Adhesive 200 Reader

Claims

1. an application unit that applies adhesive to the sheet; A folding means for folding the sheet coated with adhesive so that the surface coated with adhesive is inward; a bonding means for bonding the sheet folded by the folding means with an adhesive by applying heat and / or pressure to the sheet; a control means for controlling the amount of adhesive applied by the application unit based on print information of an image printed on the sheet before the adhesive is applied; A sheet bonding apparatus comprising: The sheet bonding apparatus is characterized in that the control means controls the application unit so that the amount of adhesive applied increases as the printing rate of an image printed on the sheet increases.

2. The control means causes an application amount per unit area of ​​the adhesive applied to an area with a high printing rate in the printed information to be greater than an application amount per unit area of ​​the adhesive applied to an area with a low printing rate in the printed information.

2. The sheet bonding apparatus according to claim 1 .

3. 2. The sheet bonding apparatus according to claim 1, further comprising a reading means for reading the printed information.

4. 2. The sheet bonding apparatus according to claim 1, further comprising a communication means for receiving the printed information read by another apparatus.

5. 5. The sheet bonding apparatus according to claim 1, wherein the application unit applies the adhesive to the sheet by utilizing an electrophotographic method.

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