JP7486260B2 - Image forming apparatus and bonding apparatus - Google Patents

Description

The present invention relates to an image forming apparatus and bonding device that applies powder adhesive to a sheet using an electrophotographic process.

Patent Documents 1 to 4 disclose an apparatus that forms an image by applying toner to a sheet using an electrophotographic process, and also applies a powder adhesive to the sheet using an electrophotographic process. The sheet with the powder adhesive applied is folded, and then heated and pressurized. As a result, the folded sheet is adhered by the powder adhesive.

JP 2006-171607 A JP 2007-193004 A JP 2008-36957 A JP 2008-162029 A

For example, when folding a sheet to form a bag, it is necessary to apply powder adhesive continuously in the conveying direction at least at one end of the width direction of the sheet perpendicular to the conveying direction. This means that powder adhesive is continuously supplied to the photoconductor from the same position in the direction of the rotation axis of the developing roller. If powder adhesive is continuously supplied to the photoconductor from the same position in the direction of the rotation axis of the developing roller, the amount of powder adhesive supplied to the photoconductor from that position on the developing roller will be reduced, and therefore the amount of powder adhesive adhering to the sheet will also be reduced. The adhesive strength at the point where the amount of powder adhesive is small will be reduced, and the final product, a bag, may not be formed.

The present invention provides a technology that suppresses the decrease in adhesive strength caused by powder adhesives.

According to one aspect of the present invention, an image forming apparatus includes a powder image forming means for forming a powder image on a conveyed sheet by adhering multiple types of powder, including toner and powder adhesive, to the sheet by an electrophotographic process, and a control means for controlling the sheet spacing between a preceding sheet and a succeeding sheet on which the powder image is formed by the powder image forming means after the preceding sheet, based on the type of powder adhered to the sheet by the powder image forming means.

The present invention makes it possible to suppress the decrease in adhesive strength caused by powder adhesives.

FIG. 1 is a diagram illustrating the configuration of an image forming apparatus according to an embodiment. FIG. 2 is a diagram illustrating the configuration of a process cartridge according to an embodiment. 1 is an explanatory diagram of a process in a folder according to an embodiment. FIG. 4 is a diagram showing the positional relationship of each powder particle attached to a sheet according to an embodiment. 1 illustrates a deliverable and adhesive regions according to one embodiment. FIG. 13 is a graph showing the relationship between the amount of powder adhesive applied per unit area and adhesive strength. FIG. 4 is an explanatory diagram of sheet interval control according to an embodiment. FIG. 13 is an illustration of results according to one embodiment. FIG. 4 is an explanatory diagram of post-rotation control according to one embodiment. FIG. 4 is an explanatory diagram of sheet interval control according to an embodiment.

The following embodiments are described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe multiple features, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicate explanations are omitted.

Figure 1 is a diagram showing the configuration of an image forming apparatus 1 according to the present embodiment, which forms an image by an electrophotographic process. The image forming apparatus 1 has an image forming unit 10 and a post-processing unit 30. The image forming unit 10 forms an image on a sheet P stored in a cassette 8 based on image data, and applies powder adhesive to an area of the sheet P specified by the image data (hereinafter, adhesive area). For this purpose, the image forming unit 10 has four process cartridges 7n, 7y, 7m, and 7c, and primary transfer rollers 4 corresponding to the process cartridges 7n, 7y, 7m, and 7c, respectively. Each process cartridge 7n, 7y, 7m, and 7c is a replacement part for the image forming apparatus 1, and is configured to be detachable from the main body of the image forming apparatus 1.

The process cartridges 7n, 7y, 7m, and 7c are all similarly configured, and will be collectively referred to as process cartridge 7 below. However, different types of powder are stored in process cartridges 7y, 7m, and 7c, and process cartridge 7n. Specifically, the powder type "toner" is stored in process cartridges 7y, 7m, and 7c, and the powder type "powder adhesive" is stored in process cartridge 7n. The colors of the toner stored in process cartridges 7y, 7m, and 7c are yellow, magenta, and cyan, respectively.

Figure 2 is a diagram showing the configuration of the process cartridge 7. The process cartridge 7 includes a photoconductor unit CC and a development unit DT. The photoconductor unit CC includes a photoconductor 101, a charging roller 102, and a cleaning member 103, and the development unit DT includes the remaining members shown in Figure 2. The photoconductor 101 is rotated clockwise in the figure during image formation. The charging roller 102 outputs a charging voltage to charge the surface of the photoconductor 101 to a uniform potential. The charged surface of the photoconductor 101 is exposed by the scanner unit 2 (Figure 1), and an electrostatic latent image is formed on the photoconductor 101. The cleaning member 103 removes any powder remaining on the photoconductor 101.

The powder is stored in the storage section 104 of the developing unit DT. The transport member 108 is rotated in the clockwise direction (arrow f direction) in the figure. As a result, the powder stored in the storage section 104 is stirred and transported to the developing chamber 109. The supply roller 106 is rotated in the clockwise direction in the figure to supply the powder to the developing roller 105 and to peel off the powder remaining on the developing roller 105 from the developing roller 105. The developing blade 107 is provided to regulate the thickness of the powder on the developing roller 105. The developing roller 105 is rotated in the counterclockwise direction in the figure to output a developing voltage. The developing voltage causes the powder carried by the developing roller 105 to adhere to the electrostatic latent image (exposed area) of the photoconductor 101. As a result, in the case of the process cartridges 7y, 7m and 7c, yellow, magenta and cyan toner images are formed on the photoconductor 101. In the case of process cartridge 7n, an image (pattern) of powder adhesive is formed on photoreceptor 101. In the following description, the toner images formed by process cartridges 7y, 7m, and 7c and the image (pattern) of powder adhesive formed by process cartridge 7n are collectively referred to as powder images. Non-volatile memory 110 stores information necessary for control during image formation, as well as information that is updated from time to time, such as the usage history of process cartridge 7.

Returning to FIG. 1, the primary transfer roller 4 provided for each process cartridge 7 outputs a primary transfer voltage to transfer the powder image on each photoconductor 101 to the transfer belt 3. During image formation, the transfer belt 3 is driven to rotate in the counterclockwise direction (V direction) in the figure. Colors other than yellow, magenta, and cyan can be formed by superimposing the toner images formed on each photoconductor 101 of the process cartridges 7y, 7m, and 7c and transferring them to the transfer belt 3. For example, black can be formed as process black by superimposing yellow, magenta, and cyan toners. The powder image transferred to the transfer belt 3 is transported to a position opposite the secondary transfer roller 5.

The sheet P stored in the cassette 8 is fed to the main transport path 1m and transported to a position facing the secondary transfer roller 5. The secondary transfer roller 5 transfers the powder image on the transfer belt 3 to the sheet P by outputting a secondary transfer voltage. In this way, the process cartridge 7, the primary transfer roller 4, the scanner unit 2, the transfer belt 3, and the secondary transfer roller 5 constitute a powder image forming unit that forms a powder image on the sheet P. Each process cartridge also constitutes a powder image forming unit in the narrow sense that forms a powder image on the photoconductor 101 using toner Ty, Tm, or Tc of each color, or a powder image using powder adhesive Tn. As described above, the electrophotographic process is a process in which an electrostatic latent image is formed on the photoconductor 101, the electrostatic latent image is developed using powder, and the developed image is transferred (attached) to the sheet P.

After the powder image is transferred, the sheet P is transported to the first fixing device 6. The first fixing device 6 heats and presses the sheet P to fix the powder image to the sheet P. When forming a powder image on both sides of the sheet P, the flapper 33 is set in a direction to guide the sheet P to a nip area between the first discharge roller 34a and the intermediate roller 34b, as shown by the dotted line in the figure. Then, the sheet P is sandwiched and transported by the first discharge roller 34a and the intermediate roller 34b toward the discharge tray 13. When the rear end of the sheet P passes the flapper 33, the rotation direction of the first discharge roller 34a and the intermediate roller 34b is switched to the opposite direction. In addition, the flapper 33 is set in a direction to guide the sheet P to the double-sided conveying path 1r, as shown by the solid line in the figure. As a result, the sheet P is transported toward the double-sided conveying path 1r. After that, the sheet P is transported again via the double-sided conveying path 1r to a position facing the secondary transfer roller 5, which is the image forming position (transfer position).

The sheet P with powder images formed on both sides, or the sheet P with a powder image formed on one side when a powder image is formed on only one side of the sheet P, passes through the first fixing device 6 and is then sandwiched and conveyed by the second discharge roller 34c and the intermediate roller 34b. At this time, the flapper 33 is set in a direction to guide the sheet P to the nip area between the second discharge roller 34c and the intermediate roller 34b, as shown by the solid line in the figure.

The powder images formed on the sheet P are classified into those using the powder adhesive Tn and those using only toner without using the powder adhesive Tn. In the following description, the powder image using the powder adhesive Tn is referred to as the "first type" powder image, and the powder image using only toner is referred to as the "second type" powder image. The sheet P on which the first type of powder image is formed requires post-processing by the post-processing unit 30, and the sheet P on which the second type of powder image is formed does not require post-processing by the post-processing unit 30. Therefore, the sheet P on which the second type of powder image is formed is discharged to the discharge tray 13. At this time, the flapper 13a is set in a direction to guide the sheet P to the tray 13 as shown by the dotted line in the figure. On the other hand, the sheet P on which the first type of powder image is formed is transported toward the intermediate path 15 of the post-processing unit 30. At this time, the flapper 13a is set in a direction to guide the sheet P to the intermediate path 15 as shown by the solid line in the figure.

The post-processing unit 30 provided downstream of the first fixing device 6 includes a folder 31, a second fixing device 32, and a discharge unit 35. In the folder 31, a folding process is performed to fold the sheet P. FIG. 3 is an explanatory diagram of the folding process. FIG. 3A shows a state in which the sheet P is sandwiched and transported in the intermediate path 15 by the first guide roller 31c and the second guide roller 31d. When the leading edge q of the sheet P passes the positions of the first guide roller 31c and the second guide roller 31d, the leading edge q of the sheet P is guided downward in the figure by the guide wall 31f (FIG. 3B). Then, as shown in FIG. 3B, the leading edge q of the sheet P is pulled into the first folding roller 31a and the second guide roller 31d, which are opposed to each other, and abuts against the wall 31g of the pull-in portion 31e. After that, the sheet P is pushed by the first guide roller 31c and the second guide roller 31d, and advances to the back of the retraction section 31e while sliding against the wall 31g. Then, as shown in FIG. 3C, the leading end q hits the end 31h of the retraction section 31e. As shown in FIG. 1, the retraction section 31e is formed below the intermediate path 15 and approximately parallel to the intermediate path 15. At the stage shown in FIG. 3C, the sheet P is wrapped around the second guide roller 31d and bent into a U-shape.

When the sheet P is further pushed in by the first guide roller 31c and the second guide roller 31d from the state shown in FIG. 3C, a bend occurs at the intermediate position r of the sheet P, as shown in FIG. 3D. When the bent intermediate position r comes into contact with the second folding roller 31b, the intermediate position r of the sheet P is pulled into the nip between the first folding roller 31a and the second folding roller 31b by the frictional force received from the second folding roller 31b, as shown in FIG. 3E. Then, as shown in FIG. 3F, the sheet P is folded with the intermediate position r as the crease, and is conveyed by the first folding roller 31a and the second folding roller 31b, and is discharged from the folder 31 with the intermediate position r as the leading edge.

If the length of the sheet P in the transport direction is L, the depth N of the retraction section 31e (FIG. 3E) can be set to L/2. The depth N of the retraction section 31e is the distance from the nip between the first folding roller 31a and the second folding roller 31b to the end 31h of the retraction section 31e. By setting the depth N in this manner, the folder 31 folds the sheet P in half (center folding) at a position halfway along the transport direction of the sheet P. The depth N of the retraction section 31e is not limited to being half the length L of the sheet P in the transport direction. The depth N of the retraction section 31e can be adjusted as desired depending on the position of the fold of the sheet P.

The configuration of the folder 31 is not limited to that shown in FIG. 3. For example, a folding mechanism can be used that presses a blade against the sheet P and pushes it into the nip area of a pair of rollers to form a crease. The folding process is not limited to folding in half, and can be a Z-fold, a triple-fold, or other folding process. 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 requires the four rollers and the retraction section 31e with a depth N that is half the sheet length, which allows the post-processing unit 30 to be made smaller.

Returning to FIG. 1, the sheet P that has passed through the folder 31 is transported to the second fixing device 32. The second fixing device 32 has a fixing configuration similar to that of the first fixing device 6. Specifically, the second fixing device 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 using an induction heating method. The pressure roller 32a is pressed against the heating roller 32b by a biasing member such as a spring, and generates a pressure force to pressurize the sheet P that passes through the nip area (pressure nip) between the heating roller 32b and the pressure roller 32a.

The sheet P folded by the folder 31 is heated and pressurized by the second fixer 32. When heated, the powder adhesive Tn in the adhesive area of the sheet P is remelted, and when pressurized, the remelted powder adhesive Tn adheres to the opposing area of the adhesive area (the area opposing the adhesive area in the folded state). After passing through the second fixer 32, the powder adhesive Tn cools and hardens, bonding the adhesive area of the sheet P to the opposing area. The sheet P that has passed through the second fixer 32 is discharged to the discharge unit 35.

The control unit 100 of the image forming device 1 has a CPU and storage devices such as a volatile memory and a non-volatile memory, and controls the entire image forming device 1. The image forming device 1 also has a sensor that acquires environmental information about the surroundings of the image forming device 1. In this embodiment, the image forming device 1 acquires the temperature and humidity around the image forming device 1 as environmental information. For this reason, the image forming device 1 has a temperature and humidity sensor 16.

As shown in FIG. 1, in this embodiment, the powder images are transferred to the transfer belt 3 in the order of process cartridges 7n, 7y, 7m, and 7c. Therefore, as shown in FIG. 4, when four types of powder images are superimposed, the powder adhesive Tn is the bottom layer (the layer in contact with the transfer belt 3) on the transfer belt 3, and the yellow, magenta, and cyan toners Ty, Tm, and Tc are superimposed on top of it. Therefore, as shown in FIG. 4, the layer of powder adhesive Tn is the top layer on the sheet P. Because the layer of powder adhesive Tn is the top layer, the folded sheet P can be adhered by the second fixing device 32.

For the yellow, magenta and cyan toners Ty, Tm and Tc, various known toners can be used. For example, toners using thermoplastic resins as binder resins can be used. Toners using polyester resins, vinyl resins, acrylic resins, styrene acrylic resins, etc. can also be used. Furthermore, the toners can contain colorants, magnetic materials, charge control agents, waxes and external additives.

The powder adhesive Tn may be a powder adhesive containing a thermoplastic resin. The powder adhesive Tn may contain a known thermoplastic resin such as polyester resin, vinyl resin, acrylic resin, styrene-acrylic resin, polyethylene, polypropylene, polyolefin, ethylene-vinyl acetate copolymer resin, or ethylene-acrylic acid copolymer resin. The powder adhesive Tn may contain a wax. Specifically, the powder adhesive Tn may contain, for example, an ester wax, which is an ester of alcohol and acid, or a hydrocarbon wax such as paraffin wax. The powder adhesive Tn may also contain a colorant. As the colorant, a known colorant such as a black colorant, a yellow colorant, a magenta colorant, or a cyan colorant may be used. The content of the colorant in the powder adhesive Tn may be 1.0% by mass or less. The powder adhesive Tn may also contain a magnetic material, a charge control agent, a wax, or an external additive.

In addition, since the powder adhesive Tn is applied to the sheet P using the electrophotographic method, for example, the weight average particle diameter of the powder adhesive Tn may be 5.0 μm or more and 30 μm or less. In addition, toner used for printing may also be used as the powder adhesive Tn as long as it satisfies the adhesive properties.

5 shows examples of products generated by the image forming device 1 and adhesive areas for generating each product. FIG. 5(A) shows a case where the product is a pressure-bonded postcard 51. In this case, substantially the entire area of one side of the sheet P becomes the adhesive area 51a, and the sheet P is pressure-bonded in a state where it is folded at the central crease 51b. FIG. 5(B) shows a case where the product is a pay slip 52. In this case, the entire circumference of the outer periphery of one side of the sheet P becomes the adhesive area 52a, and the sheet P is pressure-bonded in a state where it is folded at the central crease 52b. FIG. 5(C) shows a case where the product is a medicine bag 53. In this case, three sides of the outer periphery of one side of the sheet P except for one side become the adhesive area 53a. The powder adhesive Tn is applied so that two parallel sides of the three sides are parallel to the crease 53b. By folding the sheet P at the crease 53 and pressure-bonding it, the sheet P is formed into a bag shape.

In the case of deliverables such as the sealed postcard 51 and pay slip 52 in Fig. 5(A) and Fig. 5(B) where the contents printed on the inside (adhesive side) of the folded product are to be checked by a specific person, the adhesive strength, i.e., the amount of powder adhesive Tn applied, is adjusted so that the adhesive surface can be peeled off. On the other hand, in the case of deliverables such as the medicine bag 53 in Fig. 5(C) where the adhesive surface needs to be maintained, the adhesive strength, i.e., the amount of powder adhesive Tn applied, is adjusted so that the adhesive surface does not peel off.

Figure 6 shows the relationship between the weight per unit area of the powder adhesive Tn (hereinafter, referred to as M/S) and the adhesive strength. As shown in Figure 6, as M/S increases, the adhesive strength also increases. Note that Y in Figure 6 corresponds to the strength of the sheet P, more specifically, the force at which the sheet P begins to break, such as tearing, when a force in the direction of peeling off the adhesive surface is applied to the sheet P. From Figure 6, when M/S is greater than X, the adhesive strength is higher than the strength of the sheet P. For example, when M/S is smaller than X, the adhesive surface can be peeled off. Therefore, in the case of a product whose adhesive surface is peeled off, such as the pressure-bonded postcard 51 and the pay slip 52 shown in Figures 5(A) and 5(B), M/S may be less than X. In addition, in the case of a product whose adhesive surface is maintained, such as the medicine bag 53 shown in Figure 5(C), M/S may be greater than X.

For example, consider the case where powder images are formed continuously on multiple sheets P by one print job. When powder images are formed continuously on multiple sheets P, a predetermined reference distance R (see FIG. 7A) is provided between the rear end of the preceding sheet and the front end of the succeeding sheet. Note that, in order to increase productivity, the reference distance R is set as short as possible. Note that, in one print job, sheets P on which a first type of powder image (using powder adhesive Tn) is formed and sheets P on which a second type of powder image (not using powder adhesive Tn) is formed can be mixed.

Now, consider the case where the first type of powder image is continuously formed on the sheet P. FIG. 7(A) shows the case where the medicine bag 53 shown in FIG. 5(C) is continuously formed. Note that the shaded area 54 in FIG. 7(A) (similarly in FIG. 7(B)) is the adhesive area of the preceding sheet, and the shaded area 55 is the adhesive area of the succeeding sheet. In FIG. 7(A), the powder adhesive Tn must be continuously applied to the left side of the sheet P parallel to the conveying direction. This means that the powder adhesive Tn is continuously supplied to the photoconductor 101 from the same position in the rotation axis direction of the developing roller 105 (corresponding to the width direction perpendicular to the conveying direction). If this happens, the supply of the powder adhesive Tn from the supply roller 106 to the developing roller 105 will not be able to keep up, and the amount of powder adhesive Tn applied to the sheet P will be reduced. As a result, the required amount of powder adhesive Tn will not be applied to the adhesive area, and the adhesive surface will peel off, or the parts that need to be adhered will not be adhered in the first place, resulting in defective products (hereinafter, defective products).

Therefore, in this embodiment, as shown in FIG. 7B, when the preceding sheet and the following sheet are both sheets P on which a first type of powder image is formed, the control unit 100 widens the sheet interval between the preceding sheet and the following sheet by ΔI from the reference interval R. Note that when at least one of the preceding sheet and the following sheet is a sheet P on which a second type of powder image is formed, the control unit 100 controls the sheet interval between the preceding sheet and the following sheet to the reference interval R.

The increase amount ΔI of the sheet interval is determined based on the time it takes for the supply of powder adhesive Tn to the developing roller 105 to recover. For example, the increase amount ΔI can be set to the circumference of the developing roller 105 or a value greater than the circumference of the developing roller 105. By widening the sheet interval by at least the circumference of the developing roller 105, the powder adhesive Tn is supplied from the supply roller 106 over one revolution of the developing roller 105. In addition, taking into consideration that the amount of powder adhesive Tn in the developing chamber 109 is reduced, the increase amount ΔI can be set to a value equal to or greater than the circumference of the supply roller 106 or the distance (length) by which the sheet P is transported during one revolution of the transport member 108. For example, the increase amount ΔI can be set to the maximum value of the circumference of the developing roller 105, the circumference of the supply roller 106, and the distance (length) by which the sheet P is transported during one revolution of the transport member 108, or a value greater than the maximum value.

Figure 8 (A) shows the result when four medicine bags 53 shown in Figure 5 (C) are formed in succession. In Figure 8 (A), the increase amount ΔI is shown as a multiple of the circumference of the developing roller 105. As shown in Figure 8 (A), when a new process cartridge 7n was used in an environment with a temperature and humidity of 23 degrees and 50%, no defective product occurred in any of the four medicine bags 53 for ΔI = 3, 5, and 8. In addition, as a comparative example, when a new process cartridge 7n was used in an environment with a temperature and humidity of 23 degrees and a humidity of 50%, and ΔI = 0, a defective product occurred in the last (fourth) medicine bag 53.

As shown in FIG. 8A, when a new process cartridge 7n was used in an environment with a temperature and humidity of 15 degrees and 10%, no product defects occurred in the four medicine bags 53 when ΔI=5 and 8. However, when ΔI=3, a product defect occurred in the last medicine bag 53. Furthermore, when a process cartridge 7n at the end of its life was used in an environment with a temperature and humidity of 15 degrees and 10%, no product defects occurred in the four medicine bags 53 when ΔI=8. However, when ΔI=3, a product defect occurred in the last two medicine bags 53, and when ΔI=5, a product defect occurred in the last medicine bag 53. Note that in the image forming apparatus 1 of this embodiment, ΔI=8 corresponds to one rotation of the conveying member 108.

It is believed that the reason why poor product results are more likely to occur when the temperature and humidity are low is because the fluidity of the powder adhesive Tn decreases. Specifically, in a low-temperature, low-humidity environment, some of the powder adhesive Tn may have a high charge. If a powder adhesive Tn with a high charge is present, it becomes a nucleus around which other powder adhesives Tn with relatively low charge gather, easily forming agglomerates. This reduces the fluidity of the powder adhesive Tn, and the amount of powder adhesive Tn supplied from the supply roller 106 to the development roller 105 is reduced, which is believed to be the cause of poor product results.

It is believed that one of the reasons why defective products tend to occur when the process cartridge 7n approaches the end of its life is that the external additives in the powder adhesive Tn become embedded due to changes over time in the process cartridge 7. When the external additives in the powder adhesive Tn become embedded, the fluidity of the powder adhesive Tn decreases, which reduces the amount of powder adhesive Tn supplied to the developing roller 105. It is believed that one of the reasons why defective products tend to occur when the process cartridge 7n approaches the end of its life is that the remaining amount of powder adhesive Tn decreases, which reduces the amount of powder adhesive Tn supplied to the supply roller 106 by the conveying member 108.

Therefore, the control unit 100 can control the increase amount ΔI based on the environmental information detected by the temperature and/or humidity sensor 16. For example, the relationship between the temperature and/or humidity and the increase amount ΔI is determined in advance and stored in the storage device of the control unit 100. Then, the control unit 100 can determine the increase amount ΔI based on the temperature and/or humidity detected by the temperature and/or humidity sensor 16 when forming a powder image on the sheet P. In this case, the increase amount ΔI can be increased stepwise as the temperature and/or humidity decreases. Also, the increase amount ΔI can be controlled according to the deterioration of the process cartridge 7n. Specifically, the control unit 100 manages an evaluation value that evaluates the deterioration of the process cartridge 7n. As the evaluation value, the period of use of the process cartridge 7n, the cumulative number of rotations of the developing roller 105 of the process cartridge 7n, the number of sheets P on which the first type of powder image is formed, the total amount of powder adhesive Tn supplied to the sheet P, etc. can be used. When the evaluation value increases, the control unit 100 can increase the increase amount ΔI stepwise. It is also possible to configure the increase amount ΔI to be determined by taking into account both the environmental information and the deterioration of the process cartridge 7n. The increase amount ΔI can also be always set to a predetermined amount. For example, based on the results of FIG. 8A, it can be set to a constant ΔI = 8, at which no defective product occurred, regardless of the state of the process cartridge 7 or the temperature and humidity.

In this embodiment, if both the preceding sheet and the following sheet form a first type of powder image, the sheet interval between the preceding sheet and the following sheet is wider than the reference interval R, regardless of the adhesive area of the preceding sheet and the adhesive area of the following sheet. However, if the adhesive area 54 (first adhesive area) of the preceding sheet and the adhesive area 55 (second adhesive area) of the following sheet satisfy a predetermined expansion condition, the sheet interval between the preceding sheet and the following sheet can be wider than the reference interval R. For example, one of the expansion conditions can be that the adhesive areas of the preceding sheet and the following sheet both have a first area and a second area to which the powder adhesive Tn is continuously applied in the conveying direction, and the widthwise ranges of the first area and the second area overlap. If this expansion condition is not satisfied, the powder adhesive Tn is not continuously supplied to the preceding sheet and the following sheet from the same position on the developing roller 105. Therefore, it is less likely that the required amount of powder adhesive Tn will not be supplied to the sheet P. Therefore, even if the first type of powder image is formed on both the preceding sheet and the succeeding sheet, if the expansion condition is not satisfied, the sheet interval can be controlled to the reference interval R. The continuous length in the transport direction of the first and second regions that satisfies the expansion condition is determined in advance. For example, if the length in the transport direction of either or both of the first and second regions spans the entire length of the sheet P, at least the expansion condition can be satisfied.

Although this embodiment has been described in the context of controlling the sheet interval, the sheet interval can be replaced with the image formation timing. In other words, increasing the sheet interval between the preceding sheet and the succeeding sheet is equivalent to delaying the image formation timing for the succeeding sheet by the time it takes for the sheet P to be transported ΔI from the image formation timing when the sheet interval is the reference interval R. Note that the image formation timing is the timing at which exposure of each photoconductor 101 begins in order to form an electrostatic latent image on each photoconductor 101.

As explained above, by controlling the sheet interval between the preceding and succeeding sheets or the image formation timing of the succeeding sheet, it is possible to prevent the necessary amount of powder adhesive Tn from being supplied to the sheet P, thereby reducing defective products.

Second Embodiment
Next, the second embodiment will be described, focusing on the differences from the first embodiment. In the first embodiment, the control of the sheet interval or the image formation timing of the subsequent sheets when forming powder images on multiple sheets P by one print job was described. In this embodiment, the control between different print jobs will be described.

As shown in FIG. 9A, after the processing of the last sheet P of the preceding print job is completed, the image forming apparatus 1 performs a preparatory operation (post-rotation) after image formation. Specifically, in the post-rotation, the image forming apparatus 1 turns off each voltage used for image formation, such as the development voltage, separates the developing roller 105 from the photoconductor 101, and stops the rotation of the developing roller 105, the photoconductor 101, etc. Also, as shown in FIG. 9A, before processing the first sheet P of the following print job, the image forming apparatus 1 performs a preparatory operation (pre-rotation) before image formation. Specifically, in the pre-rotation, the image forming apparatus 1 turns on each voltage used for image formation, such as the development voltage, rotates the developing roller 105, the photoconductor 101, etc., and abuts the developing roller 105 against the photoconductor 101.

Powder adhesive Tn is supplied to the developing roller 105 until the developing roller 105 stops in the later rotation and after the developing roller 105 has been rotated in the earlier rotation. However, if the amount of supply is insufficient, the first sheet P of the subsequent job may not be sufficiently supplied with powder adhesive Tn, resulting in a defective product. Therefore, in this embodiment, as shown in FIG. 9B, when a first type of powder image is formed on the last sheet P of the preceding job, the number of rotations until the developing roller 105 is stopped in the later rotation is increased by ΔK from the reference number of rotations. The reference number of rotations is the number of rotations of the developing roller 105 in the later rotation when a second type of powder image is formed on the last sheet P of the preceding job. With this configuration, a sufficient amount of powder adhesive Tn is supplied to the developing roller 105 at the start of the subsequent job.

Figure 8 (B) shows the results when four consecutive print jobs are submitted to form only one medicine bag 53 as shown in Figure 5 (C). As shown in Figure 8 (B), when ΔK = 2, no defective product occurred in the four medicine bags 53. On the other hand, as a comparative example, when ΔK = 0, a defective product occurred in the last (fourth) medicine bag 53. Note that Figure 8 (B) shows the results when a new process cartridge 7n is used in an environment with a temperature and humidity of 23 degrees and 50%.

In this embodiment, the condition for increasing the rotation speed of the developing roller 105 in the post-rotation from the reference rotation speed is to form a first type of powder image on the last sheet P of the preceding job. However, if a subsequent job is input to the image forming apparatus 1 before the completion of the preceding job and a second type of powder image is formed on the first sheet P of the subsequent job, the rotation speed of the developing roller 105 in the post-rotation can be controlled to the reference rotation speed. Furthermore, even if a first type of powder image is formed on the first sheet P of the subsequent job, if the developer areas of the last sheet P of the preceding job and the first sheet P of the subsequent job do not satisfy the expansion condition, the rotation speed of the developing roller 105 in the post-rotation can be controlled to the reference rotation speed. This is because, in such a case, it is not necessary to continuously supply the powder adhesive Tn to the photoconductor 101 from the same position of the developing roller 105 for both the last sheet P of the preceding job and the first sheet P of the subsequent job.

The reason for increasing the number of rotations of the developing roller 105 during the post-rotation rather than the pre-rotation is to shorten the period from when the subsequent job is input to the image forming device 1 until the subsequent job is started. However, it is also possible to configure the developing roller 105 to rotate at a speed greater than the reference number of rotations during the pre-rotation period so that a sufficient amount of powder adhesive Tn is supplied to the developing roller 105 before the formation of the powder image in the subsequent job.

In this case, forming a first type of powder image on the first sheet P of the subsequent job can be set as a condition for increasing the number of rotations of the developing roller 105 in the previous rotation above the reference number of rotations. The reference number of rotations is the number of rotations of the developing roller 105 in the previous rotation when forming a second type of powder image on the first sheet P of the subsequent job. Furthermore, in addition to forming a first type of powder image on the first sheet P of the subsequent job, forming a first type of powder image on the last sheet P of the preceding job can also be set as a condition for increasing the number of rotations of the developing roller 105 in the previous rotation above the reference number of rotations. Furthermore, as described in the first embodiment, the developer area of the last sheet P of the preceding job and the first sheet P of the subsequent job can be added to the condition for increasing the number of rotations of the developing roller 105 in the previous rotation above the reference number of rotations. Also, forming a first type of powder image on the last sheet P of the preceding job can be set as a condition for increasing the number of rotations of the developing roller 105 in the previous rotation above the reference number of rotations. In this case, when a second type of powder image is formed on the last sheet P of the preceding job, the control unit 100 controls the rotation speed of the developing roller 105 in the pre-rotation to the reference rotation speed.

As described above, when a certain condition is satisfied, the developing roller 105 is rotated at a speed greater than the reference speed during the post-rotation or pre-rotation. This configuration prevents the necessary amount of powder adhesive Tn from being not supplied to the sheet P, and thus suppresses the occurrence of defective products. Rotating the developing roller 105 at a speed greater than the reference speed corresponds to increasing the interval between the last sheet P of a preceding job and the first sheet P of a subsequent job when the preceding job and the subsequent job are consecutive, compared to the interval when the developing roller 105 is rotated at the reference speed. Furthermore, rotating the developing roller 105 at a speed greater than the reference speed corresponds to delaying the image formation timing of the first sheet P of a subsequent job when the preceding job and the subsequent job are consecutive, compared to the image formation timing when the developing roller 105 is rotated at the reference speed.

Third Embodiment
Next, the third embodiment will be described, focusing on the differences from the first embodiment. In the first embodiment, the sheet interval was controlled based on the type of powder image formed on the preceding sheet and the succeeding sheet. In other words, in the first embodiment, even if a first type of powder image is formed on three consecutive sheets P, the number of consecutive sheets P is not taken into consideration when determining the sheet interval. In this embodiment, the sheet interval is controlled according to the number of consecutive times that the first type of powder image is formed on the sheets P.

Figure 10 shows the sheet spacing when a first type of powder image is formed on four consecutive sheets P. The first sheet P in Figure 10 is the first sheet P in a print job, or the preceding sheet P on which a second type of powder image is formed. As shown in Figure 10, the increase in the sheet spacing between the first and second sheets is ΔI1, the increase in the sheet spacing between the second and third sheets is ΔI2, and the increase in the sheet spacing between the third and fourth sheets is ΔI3. The increase amounts ΔI1, Δ2, and Δ3 are determined in advance and stored in the memory device of the control unit 100. In the following, these three increase amounts are expressed as "ΔI/Δ2/Δ3". As in the first embodiment, the increase amounts ΔI1, Δ2, and Δ3 are expressed as multiples of the circumference of the developing roller 105.

As described in the first embodiment, when a new process cartridge 7n was used in an environment with a temperature and humidity of 23 degrees and 50%, and four medicine bags 53 were formed in succession with an increment ΔI of 0, a defective product occurred in the fourth medicine bag 53. On the other hand, when a new process cartridge 7n was used in an environment with a temperature and humidity of 23 degrees and 50%, and an increment of "0.5/0.5/2" was used, no defective product occurred in any of the four medicine bags 53. Note that, when five or more sheets P are successively formed with a first type of powder image, the increment of the sheet interval after the fourth sheet can be fixed at ΔI3=2, which is the third (last) increment. Note that, in this embodiment, the increments ΔI1 to ΔI3 are defined from the first to third increments, but the increment information defining the increments from the first to nth increments for any n of 2 or more can be determined in advance and stored in the storage device of the control unit 100.

Note that the increment information "0.5/0.5/2" is just an example, and the present invention is not limited to such increment information. However, the increment of a certain sheet spacing is the same as or greater than the increment of the previous sheet spacing. For example, the increment information can be "0.5/1/1.5". In this case, if there are three consecutive sheets P on which the first type of powder image is formed, the spacing between the first and second sheets is increased by 0.5, and the spacing between the second and third sheets is increased by 1.

For example, the increment information can be "0/0/3". This corresponds to increasing the sheet interval from the third and fourth sheets when four or more sheets P are formed with the first type of powder image in succession. As described in the first embodiment, even when a new process cartridge 7n is used in an environment with a temperature and humidity of 23 degrees and 50%, and four medicine bags 53 are formed in succession with the increment ΔI set to 0, no defective product occurs in the first to third medicine bags 53. Therefore, in the case of such characteristics, no problem occurs even if the first increment ΔI1 and the second increment ΔI2 are set to 0, and productivity can be increased by not widening the interval. Note that the above "0/0/3" is an example, and a configuration can be made in which the sheet interval begins to be increased from the reference interval R when a predetermined number of sheets P are formed with the first type of powder image in succession.

As described above, in this embodiment, the relationship between the number of consecutive occurrences of determining that the sheet interval should be increased from the reference interval R and the increment ΔI is determined in advance, and stored as increment information in the control unit 100. This configuration can increase productivity while suppressing defective products. The increment ΔI is increased stepwise as the number of consecutive occurrences increases. As described above, the increment ΔI for the first predetermined number of occurrences can be set to 0. This corresponds to increasing the sheet interval from the reference interval R when the sheet P on which the first type of powder image is formed is consecutively formed a predetermined number of times or more. In this embodiment, the extension condition described in the first embodiment can also be used. Specifically, when the preceding sheet and the succeeding sheet satisfy the extension condition, the control unit 100 can be configured to determine the increment ΔI based on the number of consecutive occurrences of the extension condition and the increment information.

Furthermore, as described in the first embodiment, environmental information and an evaluation value for evaluating the deterioration of the process cartridge 7n can be further taken into consideration. For example, the increase amount information can be determined in advance for each environmental information and/or evaluation value and stored in the control unit 100. Also, for example, information indicating a correction method for each increase amount ΔI of the increase amount information based on the environmental information and/or evaluation value can be determined in advance and stored in the control unit 100.

[Other embodiments]
Although the above embodiments have been described using an image forming apparatus that forms a powder image using toner and powder adhesive as an example, the present invention can also be realized as a bonding device that uses only powder adhesive. When the extension condition described in the first embodiment is satisfied when applying powder adhesive to multiple sheets in one job, the bonding device increases the sheet interval between the preceding sheet and the succeeding sheet from the reference interval. In other words, when the powder adhesive Tn is applied continuously in the conveying direction to both the preceding sheet and the succeeding sheet, and the widthwise ranges to which the powder adhesive Tn is applied continuously in the conveying direction overlap, the sheet interval is increased from the reference interval.

In addition, if a subsequent job is submitted before the end of the preceding job and the last sheet of the preceding job and the first sheet of the subsequent job do not satisfy the extension condition, the bonding device controls the rotation speed of the developing roller 105 in the subsequent rotation to the reference rotation speed. On the other hand, if the extension condition is satisfied, the control unit 100 increases the rotation speed of the developing roller 105 above the reference rotation speed. Alternatively, if the last sheet of the preceding job and the first sheet of the subsequent job satisfy the extension condition, the bonding device increases the rotation speed of the developing roller 105 in the previous rotation to the reference rotation speed. In addition, if the last sheet of the preceding job and the first sheet of the subsequent job do not satisfy the extension condition, the bonding device controls the rotation speed of the developing roller 105 in the previous rotation to the reference rotation speed.

In the first and third embodiments, the control of the sheet interval or the image formation timing of the subsequent sheet when forming powder images on multiple sheets P in succession has been described. Here, we will supplement the sheet P transport control when forming powder images on multiple sheets P in succession. First, when forming a powder image on only one side of each of multiple sheets P, the multiple sheets P are simply transported sequentially to a position facing the secondary transfer roller 5 (single-sided control). Also, when forming powder images on both sides of multiple sheets P, after forming a powder image on one side of a sheet, there is a control to transport the sheet so that a powder image is formed on another sheet before forming a powder image on the other side of the sheet (double-sided first control), and a control to transport the sheet so that a powder image is not formed on another sheet (double-sided second control).

The present invention can be applied to any of the above single-sided control, double-sided first control, and double-sided second control. In the case of single-sided control and double-sided first control, the two consecutive sheets P to which the powder image forming unit transfers the powder image are different sheets P. In other words, the preceding sheet and the following sheet are different sheets P. On the other hand, in the case of double-sided second control, the two consecutive sheets P may be the same sheet. Specifically, the powder image forming unit forms a powder image on the first side (front side) of a certain sheet P, then forms a powder image on the second side (back side) of the same sheet P, and then forms a powder image on the first side (front side) of another sheet P. In this case, the preceding sheet and the following sheet may be the same sheet P. In the case of double-sided second control, the sheet P on which the powder image is formed on both sides first is the preceding sheet, and the sheet P on which the powder image is formed on both sides next to the preceding sheet is the following sheet, so that the present invention can be applied. In addition, the reference interval R in the first and third embodiments may be different for each of single-sided control, double-sided first control, and double-sided second control.

Furthermore, both-side first control and both-side second control can be mixed. For example, when a second type of powder image is formed on both sides of a sheet P, both-side first control can be used, and a second type of powder image is formed on the first side, but for a sheet P on which a first type of powder image is formed on the second side, both-side second control can be used. In the case of a sheet P on which a first type of powder image is formed on its second side, no powder image is formed on other sheets P between the formation of the powder image on the first side and the formation of the powder image on the second side, so the sheet interval becomes large. Therefore, the number of rotations of the developing roller 5 between the formation of the powder image on the first side and the formation of the powder image on the second side increases, and the powder adhesive Tn can be supplied to the developing roller 5.

The present invention can also be realized by supplying a program that realizes one or more of the functions of the above-mentioned embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program. It can also be realized by a circuit (e.g., an ASIC) that realizes one or more functions.

The invention is not limited to the above-described embodiment, and various modifications and variations are possible without departing from the spirit and scope of the invention. Therefore, the following claims are appended to disclose the scope of the invention.

7n, 7y, 7m, 7c: process cartridge, 100: control unit

Claims (25)

a powder image forming unit that forms a powder image on a sheet by attaching a plurality of types of powder, including a toner and a powder adhesive, to the sheet being conveyed by an electrophotographic process;
a control means for controlling a sheet interval between a preceding sheet and a succeeding sheet on which the powder image is formed by the powder image forming means after the preceding sheet, based on the type of the powder applied to the sheet by the powder image forming means;
An image forming apparatus comprising: The image forming apparatus according to claim 1, characterized in that the control means controls the sheet interval to a reference interval when at least one of the preceding sheet and the succeeding sheet is a sheet to which only the toner adheres. The image forming apparatus according to claim 2, characterized in that the control means increases the sheet interval from the reference interval when both the preceding sheet and the succeeding sheet are sheets to which the powder adhesive is to be applied. The image forming apparatus according to claim 2, characterized in that the control means increases the sheet interval from the reference interval when both the preceding sheet and the succeeding sheet are sheets to which the powder adhesive is applied, and when a first adhesive area to which the powder adhesive is applied in the preceding sheet and a second adhesive area to which the powder adhesive is applied in the succeeding sheet satisfy a predetermined condition. The image forming apparatus according to claim 4, characterized in that the predetermined condition is satisfied when, in the sheet conveying direction, the first adhesive region includes a first region where the powder adhesive is applied continuously to the preceding sheet, in the sheet conveying direction, the second adhesive region includes a second region where the powder adhesive is applied continuously to the succeeding sheet, and the first region and the second region overlap in the width direction perpendicular to the conveying direction. The image forming apparatus according to claim 2, characterized in that the control means increases the sheet interval from the reference interval when both the preceding sheet and the succeeding sheet are sheets to which the powder adhesive is applied a predetermined number of times in succession. The device further includes an acquisition unit for acquiring environmental information,
7. The image forming apparatus according to claim 3, wherein the control unit uses the environmental information to determine an amount of increase when the sheet interval is to be increased beyond the reference interval. The image forming device according to claim 7, characterized in that the environmental information includes at least one of temperature and humidity. The image forming apparatus according to any one of claims 3 to 8, characterized in that the control means manages an evaluation value for evaluating deterioration of the powder image forming means, and uses the evaluation value to determine the amount of increase when the sheet interval is increased from the reference interval. The image forming apparatus according to any one of claims 3 to 9, characterized in that the control means uses the number of consecutive times that the sheet spacing has been increased from the reference spacing to determine the amount of increase when the sheet spacing is increased from the reference spacing. The image forming apparatus according to any one of claims 3 to 6, characterized in that, when the control means increases the sheet interval from the reference interval, the control means increases the sheet interval from the reference interval by a predetermined amount. The powder image forming means comprises:
A first photoconductor and a second photoconductor;
an exposure unit for exposing the first photoconductor and the second photoconductor;
a first roller which is rotationally driven when the powder image is formed and which applies the powder adhesive to an area of the first photoconductor exposed by the exposure means;
a second roller that is rotationally driven when the powder image is formed and that adheres the toner to an area of the second photoconductor exposed by the exposure means,
An image forming apparatus as described in any one of claims 1 to 11, characterized in that the first roller is rotated and driven even between the time when the powder adhesive to be adhered to the preceding sheet is adhered to the first photosensitive body and the time when the powder adhesive to be adhered to the subsequent sheet is adhered to the first photosensitive body. A powder image forming unit that forms a powder image on a sheet by attaching a plurality of types of powder, including a toner and a powder adhesive, to the sheet being conveyed,
A first photoconductor and a second photoconductor;
an exposure unit for exposing the first photoconductor and the second photoconductor;
a first roller which is rotationally driven when the powder image is formed and which applies the powder adhesive to an area of the first photoconductor exposed by the exposure means;
a second roller that is rotationally driven when the powder image is formed and that adheres the toner to an area of the second photoconductor that is exposed by the exposure means;
said powder image forming means having
a control unit that controls the number of rotations of the first roller until the first roller is stopped after the job is completed, based on the type of the powder to be attached to the last sheet of the job;
An image forming apparatus comprising: The image forming apparatus according to claim 13, characterized in that the control means increases the number of rotations of the first roller until the first roller is stopped from a reference number of rotations when the last sheet of the job is a first sheet to which the powder adhesive is applied, and controls the number of rotations of the first roller until the first roller is stopped to the reference number of rotations when the last sheet of the job is a second sheet to which only the toner is applied. The image forming apparatus according to claim 14, characterized in that the control means controls the number of rotations of the first roller until the first roller is stopped to the reference number of rotations when the last sheet of the job is the first sheet, but the next job is input before the end of the job and the first sheet of the next job is the second sheet. A powder image forming unit that forms a powder image on a sheet by attaching a plurality of types of powder, including a toner and a powder adhesive, to the sheet being conveyed,
A first photoconductor and a second photoconductor;
an exposure unit for exposing the first photoconductor and the second photoconductor;
a first roller which is rotationally driven when the powder image is formed and which applies the powder adhesive to an area of the first photoconductor exposed by the exposure means;
a second roller that is rotationally driven when the powder image is formed, and that adheres the toner to an area of the second photoconductor that is exposed by the exposure means;
said powder image forming means having
a control means for controlling a number of rotations of the first roller until the start of the first job, based on a type of the powder to be adhered to a first sheet of a first job or a type of the powder adhered to a last sheet of a second job preceding the first job;
An image forming apparatus comprising: The image forming apparatus according to claim 16, characterized in that the control means increases the number of rotations of the first roller before starting the first job from a reference number of rotations when the first sheet of the first job is a sheet to which the powder adhesive is to be applied, and controls the number of rotations of the first roller before starting the first job to the reference number of rotations when the first sheet of the first job is a sheet to which only the toner is to be applied. The image forming apparatus according to claim 16, characterized in that the control means increases the number of rotations of the first roller before starting the first job from a reference number of rotations when the last sheet of the second job is a sheet to which the powder adhesive is to be applied, and controls the number of rotations of the first roller before starting the first job to the reference number of rotations when the last sheet of the second job is a sheet to which only the toner is to be applied. The image forming apparatus according to claim 16, characterized in that the control means increases the number of rotations of the first roller before starting the first job from a reference number of rotations when both the first sheet of the first job and the last sheet of the second job are sheets to which the powder adhesive is to be applied, and controls the number of rotations of the first roller before starting the first job to the reference number of rotations when at least one of the first sheet of the first job and the last sheet of the second job is a sheet to which only the toner is to be applied. a folding means for folding the sheet to which the powder adhesive has been applied by the powder image forming means;
a means for heating and pressing the sheet folded by the folding means;
20. The image forming apparatus according to claim 1, further comprising: a fixing unit that fixes the powder image on the sheet by applying heat and pressure to the sheet on which the powder image has been formed by the powder image forming unit,
21. The image forming apparatus according to claim 20, wherein the folding unit is provided downstream of the fixing unit in the sheet transport direction. An adhesive applying means for applying a powder adhesive to a conveyed sheet by an electrophotographic process;
a control means for controlling a sheet interval between the preceding sheet and the succeeding sheet based on a first adhesive region to which the powder adhesive is applied in the preceding sheet and a second adhesive region to which the powder adhesive is applied in the succeeding sheet to be processed by the application means after the preceding sheet;
A bonding device comprising: the control means controls the sheet interval to a reference interval when the first adhesive region and the second adhesive region do not satisfy the expansion condition, and increases the sheet interval from the reference interval when the first adhesive region and the second adhesive region satisfy the expansion condition;
The bonding device of claim 22, characterized in that the expansion condition is satisfied when, in the conveying direction of the sheet, the first adhesive region includes a first region where the powder adhesive is applied continuously to the preceding sheet, and in the conveying direction of the sheet, the second adhesive region includes a second region where the powder adhesive is applied continuously to the succeeding sheet, and when, in the width direction perpendicular to the conveying direction, the first region and the second region overlap. a photoreceptor, an exposure means for exposing the photoreceptor to light, and a roller for applying a powder adhesive to an area of the photoreceptor exposed by the exposure means, and an application means for applying the powder adhesive to a sheet being conveyed;
a control means for controlling the number of rotations of the roller until the roller is stopped after the first job is completed or the number of rotations of the roller until the second job is started, based on a first adhesive area to which the powder adhesive is applied on the last first sheet of the first job and a second adhesive area to which the powder adhesive is applied on the first second sheet of a second job following the first job;
A bonding device comprising: the control means controls the rotation speed of the roller to a reference rotation speed when the first adhesive region and the second adhesive region do not satisfy the expansion condition, and increases the rotation speed of the roller above the reference rotation speed when the first adhesive region and the second adhesive region satisfy the expansion condition;
The bonding device of claim 24, characterized in that the expansion condition is satisfied when, in the conveying direction of the sheet, the first adhesive region includes a first region where the powder adhesive is applied continuously to the first sheet, and in the conveying direction of the sheet, the second adhesive region includes a second region where the powder adhesive is applied continuously to the second sheet, and in the width direction perpendicular to the conveying direction, the first region and the second region overlap.

Images