Paper folding device and image forming system

Abstract

To prevent folded bundles from getting caught in a conveyance path to cause paper jamming.SOLUTION: A paper holding device includes: a conveyance roller pair that conveys a recording medium so as to freely advance / retreat; multiple folding roller pairs that convey the recording medium in a direction perpendicular to the direction in which the pair of conveyance rollers convey the recording medium so as to freely advance / retreat; a pair of guide means pair that execute folding processing of causing the recording medium to enter a nip of the folding roller pairs and folding it while alternately switching the folding roller pairs that guide the recording medium; and a control part that controls the folding roller pairs, the conveyance roller pair, and the guiding means, and skips the folding processing at least once when the number of folds of the folded bundle that has been subjected to the folding processing reaches the maximum number of folds that is the upper limit of a height that can be conveyed.SELECTED DRAWING: Figure 19

Description

Technical Field

[0001] The present invention relates to a paper folding device and an image forming system.

Background Art

[0002] Conventionally, a paper folding device that performs a process of folding a recording medium in a bellows shape is known.

[0003] Patent Document 1 discloses a technique of constructing two folded bundles based on the center of a recording medium for the purpose of facilitating the unfolding of the recording medium to be folded during use.

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, according to the conventional technology, there is a problem that when discharging the folded bundle, the side surface of the folded bundle gets caught in the conveyance path (such as the discharge port) of the paper folding device and the recording medium gets jammed. Also, according to the conventional technology, in order to prevent the side surface of the folded bundle from getting caught in the conveyance path (such as the discharge port) of the paper folding device when discharging the folded bundle, there is a problem that it becomes necessary to set a certain upper limit on the number of folding times of the folded bundle. Further, according to the conventional technology, in order to prevent the side surface of the folded bundle from getting caught in the conveyance path (such as the discharge port) of the paper folding device when discharging the folded bundle, there is a problem that when detecting the limit of the number of folding times during the bellows folding process, the folding operation has to be stopped and the paper has to be discharged.

[0005] The present invention has been made in view of the above, and an object thereof is to prevent the folded bundle from getting caught in the conveyance path and causing paper jams.

Means for Solving the Problems

[0006] To solve the above-mentioned problems and achieve the objective, the present invention is characterized by comprising: a pair of transport rollers for transporting a recording medium so that it can advance and retract; a plurality of pairs of folding rollers for transporting the recording medium so that it can advance and retract in a direction perpendicular to the direction in which the transport roller pair transports the recording medium; a pair of guiding means for performing a folding process in which the recording medium is guided into the nip of the folding roller pair and folded, while alternately switching the folding roller pair that guides the recording medium; and a control unit that controls the folding roller pair, the transport roller pair and the guiding means, and skips the folding process at least once when the number of folds of the folded bundle after the folding process has been performed reaches the maximum number of folds which is the upper limit of the transportable height. [Effects of the Invention]

[0007] According to the present invention, it is possible to prevent paper jams caused by folded paper bundles getting caught in the transport path. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a cross-sectional view showing a schematic configuration of an image forming system according to an embodiment. [Figure 2] Figure 2 is a side view showing the operation of the paper folding device. [Figure 3] Figure 3 is a side view showing the operation of the paper folding device. [Figure 4] Figure 4 is a side view showing the operation of the paper folding device. [Figure 5] Figure 5 is a side view showing the operation of the paper folding device. [Figure 6] Figure 6 is a perspective view showing the configuration of the induction mechanism. [Figure 7] Figure 7 is a perspective view showing the guide configuration of the guide means using rail grooves. [Figure 8] Figure 8 is a schematic diagram illustrating the drive configuration of the paper folding device. [Figure 9] Figure 9 is a block diagram illustrating the schematic of the control system of the image forming system. [Figure 10]Figure 10 shows the conventional bellows folding operation. [Figure 11] Figure 11 is a cross-sectional view of a folded bundle that has undergone accordion folding. [Figure 12] Figure 12 is a flowchart that schematically shows the flow of the paper folding process. [Figure 13] Figure 13 is a flowchart showing the processing procedure for the paper folding operation of a paper folding device. [Figure 14] Figure 14 is a flowchart showing the processing procedure for the paper folding operation of a paper folding device. [Figure 15] Figure 15 is a flowchart showing the processing procedure for the paper folding operation of a paper folding device. [Figure 16] Figure 16 is a flowchart illustrating the general flow of the process for forming the non-folded section. [Figure 17] Figure 17 shows the formation process of a non-folded section without the addition of a crease. [Figure 18] Figure 18 shows the process of forming a non-folded section without adding a crease. [Figure 19] Figure 19 is a cross-sectional view showing an example of a folded bundle formed by dividing without adding a crease. [Figure 20] Figure 20 shows the process of forming a non-folded section to which a crease is added. [Figure 21] Figure 21 shows the process of forming a non-folded section to which a crease is added. [Figure 22] Figure 22 shows the process of forming a non-folded section to which a crease is added. [Figure 23] Figure 23 shows the process of forming a non-folded section to which a crease is added. [Figure 24] Figure 24 shows the process of forming a non-folded section to which a crease is added. [Figure 25] Figure 25 is a cross-sectional view showing an example of a folded bundle formed by adding creases (fold lines) and dividing it. [Figure 26] Figure 26 is a cross-sectional view showing another example of a folded bundle formed by adding a crease and dividing it.

Best Mode for Carrying Out the Invention

[0009] The embodiments of the paper folding apparatus and the image forming system will be described in detail below with reference to the attached drawings.

[0010] FIG. 1 is a cross-sectional view showing a schematic configuration of an image forming system according to an embodiment. First, the overall configuration of the image forming system according to the present embodiment will be described with reference to FIG. 1. The image forming system according to the present embodiment mainly includes a copying machine 200 which is an image forming apparatus, and a paper folding apparatus 100. The paper folding apparatus 100 is connected to the back surface of the copying machine 200. The paper folding apparatus 100 folds a sheet of paper (recording medium) P conveyed from the copying machine 200 in a bellows shape. Needless to say, the copying machine 200 and the paper folding apparatus 100 may be an integrated image forming apparatus.

[0011] The paper folding apparatus 100 includes a connecting portion with a copying machine 200 not shown, an end face folding portion 120 that folds the end face of the leading end of the sheet of paper P, a paper folding portion 130 that folds the sheet of paper P in a bellows shape in the conveyance direction, and a tray 140 that discharges and stacks the folded sheet of paper P.

[0012] An image reading device 205 is arranged in the copying machine 200, and a manual paper feed tray 208 is arranged below it. The sheet of paper P set on the manual paper feed tray 208 is temporarily stopped by a registration roll 207 and supplied to an image forming unit 206 at an appropriate timing. The image forming unit 206 forms a latent image corresponding to image data on a photoreceptor not shown, develops this latent image with toner, transfers this toner onto the sheet of paper P, and fixes it with a fixing device 210. When paper folding is to be performed, a recorded paper discharge roll 211 discharges the recorded sheet of paper P on which the toner has been fixed by the fixing device 210 to the paper folding apparatus 100. When paper folding is not to be performed, a switching claw and an upper paper discharge roll 209 not shown discharge the recorded sheet of paper P into the body of the copying machine 200.

[0013] Next, the case of folding the sheet of paper P will be described.

[0014] The paper P discharged from the recorded paper discharge roll 211 is sent to the paper folding device 100. The paper folding device 100 transports the paper P using the entrance transport roller pair 106, 107, and if the end face of the paper P needs to be folded, the end face of the leading edge of the paper P is folded by the end face folding section 120. After the end face of the leading edge of the paper P is folded by the end face folding section 120, the paper folding device 100 folds the paper P in an accordion shape in the transport direction using the paper folding section 130, and stacks the folded paper P in the tray 140.

[0015] Next, we will describe the paper folding device 100 that folds the paper P in an accordion shape in the transport direction.

[0016] Here, Figures 2 to 5 are side views showing the operation of the paper folding device 100. Figures 2 to 5 are enlarged views of the paper folding section 130 in Figure 1.

[0017] As shown in Figure 2, the paper folding section 130 has a tip detection sensor 15 for detecting the leading edge of the paper P positioned at the entrance of the paper folding section 130. Downstream of the tip detection sensor 15, the paper folding section 130 is provided with a transport roller pair 14 that transports the paper P so that it can move forward and backward. Downstream of the transport roller pair 14, the paper folding section 130 has folding roller pairs 11 (11a, 11b) and 12 (12a, 12b) positioned that transport the paper P in a direction perpendicular to the direction in which the transport roller pair 14 transports the paper P. The folding roller pairs 11 and 12 rotate synchronously in the forward and reverse directions to fold the paper P into an accordion shape. That is, the folding roller pairs 11 and 12 transport the paper P so that it can move forward and backward in a direction perpendicular to the direction in which the transport roller pair 14 transports the paper P.

[0018] The paper folding unit 130 is equipped with a left folding width detection sensor 16 and a right folding width detection sensor 17 on the outside of the folding roller pair 11, respectively, to detect the leading edge of the paper P and the folded edge of the folded paper P. The paper folding unit 130 also places a lower guide plate 18 between the folding roller pairs 11 and 12 to guide the edge of the folded paper P to the roller pairs 11 and 12.

[0019] The paper folding section 130 is provided with a pair of guide means 20 and 21 on the outside of the transport roller pair 14, and switches the guidance of the leading edge of the paper P in the transport direction to either the side of the folding roller pair 11 or 12. The guide means 20 and 21 have an arc-shaped trajectory so as to contact the lower folding rollers 11b and 12b, respectively, and perform an advancing and retracting movement by being rotationally driven by drive gears 22 and 23. That is, the guide means 20 and 21 alternately switch the folding roller pair 11 and 12 that guide the paper P, and perform the folding process by guiding the paper P into the nip of the folding roller pair 11 and 12 and folding it.

[0020] The paper folding unit 130 guides the leading edge of the paper P to the vicinity of the folding roller pair 11, 12 using the guide means 20, 21, and causes it to enter the nip of the folding roller pair 11, 12. At this time, the paper folding unit 130 selects which nip of the folding roller pair 11, 12 the leading edge of the paper P should enter by moving either the guide means 20 or 21. Here, the guide means 20 that guides to the right folding roller pair 12 is called the right guide means, and the guide means 21 that guides to the left folding roller pair 11 is called the left guide means. Furthermore, as shown in Figure 4, the guide means 20, 21 are also configured to guide the inside of the paper P to either the nip of the folding roller pair 11, 12 when the paper P is folded. At this time, the rollers 20a, 21a configured at the tips of the guide means 20, 21 come into contact with the lower folding rollers 11b, 12b, respectively.

[0021] Here, Figure 6 is a perspective view showing the configuration of the guide means 20 and 21, and Figure 7 is a perspective view showing the guide configuration of the guide means 20 and 21 by rail grooves. Note that the guide means shown in Figures 6 and 7 is the left guide means 21, but the right guide means is symmetrical and has the same configuration.

[0022] As shown in Figure 6, the guiding means 21 has side plates 21h with gear sections on both sides of the left guiding means 21, connecting the side plates 21h, and providing a guide plate 21d between the side plates 21h to guide the leading edge of the paper P. Furthermore, the guiding means 21 also has a stay 21e between the side plates 21h to support the side plates 21h. The guiding means 21 has a light-shielding plate 21c on the stay 21e that shields the guiding means home position sensors (hereinafter referred to as guiding means HP sensors) 24, 25 shown in Figure 2. The guiding means 21 also has a roller 21a with a width greater than or equal to the maximum paper width at the leading edge between the side plates 21h. The roller 21a is supported not only by the side plates 21h but also by the leading edge 21g of the guide plate 21d as a bearing. Here, the leading edge 21g of the guide plate 21d supports the entire width of the roller 21a, but it may be supported only partially. Furthermore, although the tip portion 21g is coated with a fluororesin such as Teflon (registered trademark), the guide plate 21d itself may be made of a resin material with a low coefficient of friction. Also, the roller 21a may be made of pipe material.

[0023] Furthermore, the guide means 21 has multiple rollers 21f protruding from the outside of both side plates 21h. As shown in Figure 7, a pair of rails 60 are provided on both the outside of the guide means 20 and 21. Rail grooves 60a and 60b are cut in an arc shape into the rails 60 so that the guide means 20 and 21 contact the lower folding rollers 11b and 12b respectively, and the rollers 21f are loosely fitted into the rail grooves 60. This configures the guide means 20 and 21 to move up and down in a circular trajectory. That is, the rollers 21f contact the rail grooves 60a and 60b, the gear parts 20b (not shown) and 21b of the guide means 20 and 21 mesh with the drive gears 22 and 23, and the rollers 21f roll within the rail grooves 60a and 60b, causing the guide means 20 and 21 to reciprocate in an arc trajectory so as to contact and separate from the lower folding rollers 11b and 12b, respectively.

[0024] Figure 8 is an explanatory diagram illustrating the drive configuration of the paper folding device 100.

[0025] In Figure 8, the drive-side roller of the transport roller pair 14 receives driving force from the transport motor 52 via a drive belt 51 through a pulley 50 connected to its end, and rotates in the transport direction (direction of the arrow in Figure 8). A tip detection sensor 15 is also provided near the center of the transport roller pair 14.

[0026] Since the drive configurations for the guide means 20 and 21 are symmetrical and identical, we will use the left guide means 21 for this explanation. First, drive gears 23 mesh with the gear portions 21b at both ends of the left guide means 21. Since the drive gears 23 at both ends are mounted on the same drive shaft 54 ​​and driven, the left guide means 21 moves parallel to the drive shaft 54 ​​as the drive shaft 54 ​​rotates. The drive shaft 54 ​​is connected to a drive pulley 42a via a torque limiter 42b, and the drive pulley 42a and drive pulley 40 are connected and driven by a drive belt 41. Furthermore, a drive pulley 55 on the same shaft 39 as the drive pulley 40 is connected to the left motor 36 of the guide means via a drive belt 37. Therefore, when the left motor 36 of the guide means rotates in the direction of the arrow, the left guide means 21 moves in the direction of the arrow. At that time, if a load exceeding the rotational load torque of the torque limiter 42b is applied to the left guide means 21, the torque limiter 42b and the drive pulley 42a are configured to slip while generating torque. Furthermore, the end of the guide means 21 has a light-shielding plate 21c, which shields the left guide means HP sensor 25 when the guide means 21 is in the upward waiting position, thereby detecting the waiting position. The right guide means 20 has a similar configuration, and in Figure 8, the right guide means 20 shows the direction of rotation when it is descending.

[0027] Next, the drive of the folding roller pairs 11 and 12 will be explained. A drive pulley 35 is connected to the end of the upper folding roller 11a, and a drive pulley 33b is connected to the end of the upper folding roller 12a. Drive pulleys 35 and 33b are connected by a drive belt 34. Furthermore, a drive pulley 33a, which is integrated with drive pulley 33b, is connected to drive pulley 57a via drive belt 31, and a drive pulley 57b, which is integrated with drive pulley 57a, is connected to the folding motor 30 via drive belt 56. Therefore, when the folding motor 30 rotates in the direction of the arrow in Figure 8, the upper folding rollers 11a and 12a rotate synchronously in the direction of the arrow. In addition, a drive belt (not shown) connects the upper folding rollers 11a and 12a and the lower folding rollers 11b and 12b, so that when the folding motor 30 rotates, the folding roller pairs 11 and 12 rotate synchronously in the conveying direction, both the upper and lower folding rollers. Furthermore, a right folding width detection sensor 17 and a left folding width detection sensor 16 are positioned near the outer center of the pair of folding rollers 11 and 12, respectively.

[0028] Figure 9 is a block diagram illustrating the schematic of the control system of the image forming system.

[0029] The control system of the copier 200 consists of an operation unit 201 and a main control board 202. The control system of the paper folding device 100 consists of a paper folding controller 10 which is the control unit, an end-tip detection sensor 15, a right HP sensor 24 for the guidance means, a left HP sensor 25 for the guidance means, a left folding width detection sensor 16, a right folding width detection sensor 17, a folding motor 30, a transport motor 52, a right motor 43 for the guidance means, and a left motor 36 for the guidance means.

[0030] The paper folding controller 10 has a hardware configuration that utilizes a standard computer, including a CPU (Central Processing Unit), ROM (Read Only Memory) for storing programs, and RAM (Random Access Memory). The paper folding controller 10 loads the programs stored in ROM into RAM, and the CPU executes them to realize various functions, such as the paper folding function described later.

[0031] The paper folding controller 10 controls the motors 30, 52, 43, and 36. The main control board 202 receives input signals such as folding type and size from the operation unit 201 of the copier 200, and this information is sent to the paper folding controller 10. Based on the sensor information, the controller controls each motor to fold the paper P.

[0032] In the configuration shown in Figure 9, the paper folding controller 10 controls the motors 30, 52, 43, and 36. The main control board 202 receives input signals such as the type of fold and size from the operation unit 201 of the copier 200. This information, along with necessary information such as the type of paper P, is sent to the paper folding controller 10. Based on the sensor information, the controller controls each motor to fold the paper P.

[0033] Here, Figure 10 shows a conventional accordion folding operation. As shown in Figure 10, the paper folding section 130 of the paper folding device 100 forms folding positions alternately on the left and right sides with respect to the paper P conveyed by the transport roller pair 14, using a folding roller pair 11 that forms a folding position on the left side by a nip, a folding roller pair 12 that forms a folding position on the right side by a nip, a guidance means 21 that guides the paper P to the folding roller pair 11, a guidance means 20 that guides the paper P to the folding roller pair 12, a folding width right detection sensor 17 for measuring the folding width from the left side, and a folding width left detection sensor 16 from the right side.

[0034] In the example shown in Figure 10, the transport roller pair 14 rotates downward, the folding roller pair 11 and folding roller pair 12 rotate to the right, and the guiding means 20 is in operation. Through these operations, the paper folding section 130 attempts to form a fold on the right side of the paper P by the folding roller pair 12.

[0035] By repeating this operation alternately on the left and right sides, the paper folding unit 130 forms an accordion fold on the paper P and finally discharges a single folded bundle.

[0036] Figure 11 is a cross-sectional view of a folded stack of paper that has undergone accordion folding. As shown in Figure 11, typically, the height of the folded stack increases as the number of folds increases. For example, if the height of the folded stack that can be transported within the paper folding device 100 is Hmax, then if the height of the folded stack becomes H, problems such as paper jams will occur during transport and discharge within the paper folding device 100. Alternatively, a constraint may arise in which it is not possible to set the number of folds to such an extent that the height of the folded stack becomes H.

[0037] Therefore, in this embodiment, when the number of folds required for the paper P to reach a height that makes transport difficult is specified, the folding operation is skipped by one step before reaching the upper limit of the transportable height, thereby dividing the resulting folded bundle. As a result, the overall height of the folded bundle is suppressed, preventing the bundle from getting caught in the transport path (such as the discharge port) and causing a paper jam, and also allowing a higher number of transportable folds to be set than in conventional designs. This will be described in detail below.

[0038] Here, Figure 12 is a flowchart that schematically shows the flow of the paper folding process.

[0039] As shown in Figure 12, the paper folding controller 10 of the paper folding device 100 accepts the setting of necessary information such as the paper size and paper type of the paper P (step S201).

[0040] The paper folding controller 10 also accepts the setting of the folding type (step S202). The folding type may be, for example, the type of paper folding to put into the right folding roller 12 or the type of paper folding to put into the left folding roller 11, or whether or not to make a crease (fold line) when folding in an accordion style.

[0041] Next, the paper folding controller 10 calculates the maximum number of folds Nmax that can be transported (step S203). More specifically, the paper folding controller 10 sets the maximum number of folds Nmax just before the paper P reaches a height that makes transport difficult.

[0042] Furthermore, the paper folding controller 10 can switch between automatically setting the maximum number of folds Nmax that can be transported as the number of folds that can be transported, or allowing the user to set it arbitrarily in advance. If only the number of folds that can be transported is set, the final folded stack may become extremely low, resulting in an unbalanced appearance. In this embodiment, the paper folding controller 10 allows the user to set the number of folds for the folded stack in advance, thereby making the height of the discharged folded stacks flat.

[0043] Next, the paper folding controller 10 performs an initial setting where the number of folds N=0 (step S204).

[0044] Next, the paper folding controller 10 performs the paper folding operation (step S205).

[0045] Here, we will describe the sequence of paper folding operations performed by the paper folding device 100 in step S205.

[0046] Figures 13 to 15 are flowcharts showing the processing procedure for the paper folding operation of the paper folding device 100.

[0047] First, when a signal indicating paper folding is input from the main unit operation unit 201 of the copier 200, the signal is sent to the paper folding controller 10 via the main unit control board 202, with necessary information such as the type of paper P added. In this case, on the paper folding device 100 side, the flowchart in Figure 13 starts, and the paper folding controller 10 turns ON the left motor 36 of the induction means in the forward direction (step S0-1), turns OFF the left HP sensor 25 of the induction means, and then turns OFF the left motor 36 of the induction means after T10 seconds (step S0-2). Subsequently, the paper folding controller 10 turns ON the left motor 36 of the induction means in the reverse direction (step S0-3), turns ON the left HP sensor 25 of the induction means, and then turns OFF the left motor 36 of the induction means after T11 seconds (step S0-4), and adjusts the standby position of the left induction means 21.

[0048] Next, the paper folding controller 10 adjusts the standby position of the right guidance means 20 in the same way as the adjustment of the left guidance means 21, through steps S0-5 to S0-8 of the flowchart, using the right guidance means motor 43 and the right guidance means HP sensor 24. The standby positions of the guidance means 20 and 21 are determined by the paper folding controller 10, which obtains necessary information such as the folding type, paper size, and paper type from the main control board 202, and uses various sensors and information to determine the position. After that, the paper folding controller 10 jumps to step S shown in Figure 14, turns on the transport motor 52, and the transport roller pair 14 begins to rotate in the direction of the arrow (step S0).

[0049] Then, as shown in the flowchart of Figure 14, when the tip detection sensor 15 is turned ON (step S1), the paper folding controller 10 determines whether the first paper P to be transported is of the type to be fed into the right folding roller 12 based on the paper folding type signal input from the main unit operation unit 201 (step S2). Here, we will explain the case where the paper folding type signal indicates that the first paper P to be transported is of the type to be fed into the right folding roller 12 (Yes in step S2). Next, the paper folding controller 10 turns ON the folding motor 30 and starts rotating in the direction of the arrow in Figure 2 (which is referred to as forward rotation here) (step S3). The paper folding controller 10 also turns ON the right motor 43 of the guide means and starts moving the right guide means 20 in Figure 2 from the solid line position to the dashed line position (the direction of rotation at this time is referred to as forward rotation) (step S4).

[0050] At this time, the paper folding controller 10 turns OFF the right HP sensor 24 of the guide means (step S5), and after a driving time T1 seconds when the right guide means 20 reaches the dashed line position from the solid line position, it turns OFF the right motor 43 of the guide means (step S6). At this time, as shown in Figure 2, the roller 20a at the tip of the right guide means 20 and the lower folding roller 12b do not come into contact, and the right guide means 20 is stopped with a slight gap. In this state, the paper folding controller 10 moves the leading edge of the paper P into the nip of the right folding roller pair 12 as shown in Figure 2, and turns ON the right folding width detection sensor 17 (step S7). After that, the paper folding controller 10 turns ON the right motor 43 of the guide means in the reverse direction (step S8) and turns ON the right HP sensor 24 of the guide means (step S9) in order to return the right guide means 20 to the standby position. Then, after 11 seconds T, the paper folding controller 10 turns off the right motor 43 of the induction means (step S10) and returns the right induction means 20 to the standby state at the solid line position in Figure 2.

[0051] Next, the paper folding controller 10 determines whether there is another fold after the leading edge of the paper P enters the right folding roller pair 12 (step S11). If there is another fold (Yes in step S11), the paper folding controller 10 turns on the right folding width detection sensor 17, and after T4 seconds, turns off the folding motor 30 (step S12). Then, in order to guide the inside of the paper P to the nip of the left folding roller pair 11, it turns on the left motor 36 of the guide means and starts moving the left guide means 21 in Figure 3 in the direction of the arrow (the direction of rotation at this time is considered forward rotation) (step S13). At this time, the paper folding controller 10 turns off the left HP sensor 25 of the guide means (step S14).

[0052] The paper folding controller 10 turns on the tip detection sensor 15 as shown in Figure 3, simultaneously with the operation of the left guide means 21, and then turns on the folding motor 30 in the reverse direction after T3 seconds (step S15). At this time, the movement speed of the left guide means 21 is set to be faster than the speed at which the paper P sags, so the sag of the paper P disappears as shown by the dashed line in Figure 3, and the roller 21a at the tip of the left guide means 21 comes into contact with the paper P. At this time, the movement speed of the left guide means 21 cannot move faster than the speed at which the paper P sags, so a load is placed on the torque limiter 42b, and it begins to slip while generating torque between the torque limiter 42b and the drive pulley 42a. Therefore, the roller 21a at the tip of the left guide means 21 applies tension to the paper P by the amount of the free-spinning torque of the torque limiter 42b, and the paper P moves while maintaining a taut state, and as shown in Figure 4, the roller 21a at the tip of the left guide means 21 brings the paper P into contact with the left lower folding roller 11b.

[0053] The paper folding controller 10 continues to feed the paper P, bringing the leading edge of the folded paper P to the left folding width sensor 16 and turning it ON (step S16). After that, the paper folding controller 10 stops the left motor 36 of the guide means to return the left guide means 21 to the standby position (step S17), then turns it ON in the reverse direction (step S18), and turns ON the left HP sensor 25 of the guide means (step S19). After 11 seconds T, the paper folding controller 10 turns OFF the left motor 43 of the guide means (step S20), returns the right guide means 21 to the standby position shown by the solid line in Figure 2, and thus completes the first fold.

[0054] Once the folding operation (1 time) is completed, the paper folding controller 10 increments the number of folds by 1 (N=N+1) (step S71).

[0055] Next, the paper folding controller 10 determines whether the paper P has passed the transport roller pair 14 (step S72).

[0056] When the paper folding controller 10 detects that the paper P has passed the transport roller pair 14 (Yes in step S72), it enters the discharge operation flow C.

[0057] On the other hand, if the paper P has not passed through the paper feed roller pair 14 (No. in step S72), the paper folding controller 10 determines whether the number of folds N = Nmax (step S73).

[0058] The paper folding controller 10 proceeds to step S76 if the number of folds N is not equal to Nmax (No. in step S73), that is, if the number of folds N has not reached the maximum number of folds Nmax.

[0059] On the other hand, the paper folding controller 10 performs the operation to form an unfolded section L' when the number of folds N = Nmax (Yes in step S73), that is, when the number of folds N has reached the maximum number of folds Nmax (step S74). The operation to form an unfolded section L' in step S74 will be described later.

[0060] After the paper folding controller 10 performs the operation to form the non-folding section L' (step S74), it sets the number of folds N=0 (step S75) and proceeds to step S76.

[0061] On the other hand, in step S11, when determining whether there is a fold to go next, if there is no fold (No. in step S11), the paper output direction is on the left-fold roller side, so the paper will switch back once before being ejected. When the right-fold roller pair 12 is transporting the paper P and the rear end of the paper P passes the tip detection sensor 15, the paper folding controller 10 turns off the folding motor 30 (step S22), then reverses the folding motor 30 (step S23), transports the rear end of the paper P toward the left-fold roller pair 11, and enters the ejection operation flow C.

[0062] Furthermore, in step S2, the paper folding controller 10 determines whether the first paper P being transported is of the type that should be placed in the right folding roller 12. If it is of the type that should be placed in the left folding roller 11 (No. in step S2), the paper folding controller 10 operates in the same way as in steps S3 to S21, except that the left and right sides are reversed compared to when it is placed in the right folding roller 12. However, in step S32, the next determination of whether or not there is a fold indicates that there is no fold. In this case, the paper folding controller 10 proceeds directly to the discharge operation flow C because the paper discharge direction is towards the left folding roller 11 and there is no need to switch back before discharge.

[0063] Furthermore, the paper folding controller 10 operates in the same manner as in steps S71 to S75 during steps S81 to S85.

[0064] Here, the paper folding controller 10 determines whether or not there are repeat folds (steps S76, S42). If the first fold is on the left side and there are repeat folds (Yes in step S76), it proceeds to the repeat fold flow B on the right side. If there are no repeat folds (No in step S76), it does not need to switch back once before ejecting, so it proceeds directly to the ejection operation flow C.

[0065] Furthermore, if the first fold is on the right side and there is a repeat fold (Yes in step S42), the paper folding controller 10 enters flow A for the repeat fold on the left side. If there is no repeat fold (No in step S42), the paper folding controller 10 needs to switch back once before ejecting. Therefore, when the right folding roller pair 12 is transporting the paper P and the rear end of the paper P passes the tip detection sensor 15 and turns OFF, the folding motor 30 is turned OFF and stopped (step S43). Then the folding motor 30 is reversed (step S44), and the rear end of the paper P is transported toward the left folding roller pair 11, and the paper enters ejection operation flow C.

[0066] Next, in the case of repetitive folding flows A and B, in left-fold flow A, the timing for reversing the folding motor 30 in step S48 is almost the same as in the first fold steps S12~S21 and S71~S75, and in the case of repetitive folding, the paper folding controller 10 reverses it 6 seconds after the right folding width detection sensor 17 is turned ON. Similarly, in right-fold flow B, the timing for rotating the folding motor 30 forward in step S58 is almost the same as in the first fold steps S33~S42 and S81~S85, and in the case of repetitive folding, the paper folding controller 10 reverses it 6 seconds after the right folding width detection sensor 16 is turned ON. Similarly, in right-fold flow B, the timing for rotating the folding motor 30 forward in step S58 is almost the same as in the first fold flowchart steps S33 to S42 and S81~S85, and in the case of repetitive folding, the paper folding controller 10 reverses it 6 seconds after the right folding width detection sensor 16 is turned ON. If there are further repeated folds, the paper folding controller 10 repeats flows A and B. If the final fold is on the right side, the paper output direction is on the left-folding roller side, so the controller switches back once before outputting. When the right-folding roller pair 12 is transporting the paper P and the rear end of the paper P passes the tip detection sensor 15 and turns OFF, the paper folding controller 10 turns OFF the folding motor 30 (step S65). Then, it reverses the folding motor 30 (step S66) and transports the rear end of the paper P toward the left-folding roller pair 11, entering output operation flow C. If the final fold is on the left side, the paper folding controller 10 enters output operation flow C directly.

[0067] Finally, in the discharge operation flow C, the paper folding controller 10 turns OFF the left folding width detection sensor 16 when the trailing edge of the paper P passes it (step S67), then stops the folding motor 30 (step S68), stops the transport motor 52 (step S69), and completes the discharge. As the paper P is repeatedly folded to the right and left in this manner, it becomes a folded bundle, which is then nipped by the folding roller pairs 11 and 12 and transported.

[0068] When the paper P is repeatedly folded to the right and then to the left in this manner, the paper P becomes a folded bundle, which is then nipped by folding roller pairs 11 and 12 and transported.

[0069] Next, the formation operation of the non-folding section L' in steps S74, S84, S94, and S104 will be described.

[0070] Here, Figure 16 is a flowchart that schematically shows the flow of the process for forming the non-folded section. As shown in Figure 16, the paper folding controller 10 first determines whether to add a crease (fold line) (step S111).

[0071] If the paper folding controller 10 determines, based on the settings, that no creases (fold lines) should be added (No. in step S111), it performs transport for the non-folding section L' (step S113).

[0072] Here, Figures 17 and 18 show the process of forming a non-folded section without adding a crease (fold line).

[0073] Figure 17 shows the point in time when the paper folding process is skipped once to form a non-folded section L'. In this embodiment, the non-folded section L' is three times the length of the fold width L, which is equivalent to skipping one fold. As shown in Figure 17, forming the non-folded section L' divides the paper into two sections: folded bundle Pa and folded bundle Pb.

[0074] Figure 18 shows the point in time when the folding process is completed and the folded bundle is discharged. As shown in Figure 18, the height of the entire folded bundle is divided into two by the formation of the folded bundle Pa and the folded bundle Pb in the non-folding section L', thereby suppressing the overall height of the folded bundle.

[0075] Here, Figure 19 is a cross-sectional view showing an example of a folded bundle formed by dividing without adding creases (fold lines). As shown in Figure 19, in this embodiment, before reaching the number of folds that makes the folded bundle transportable within the paper folding device 100 Hmax, that is, when it reaches the height H', a non-folded section L' is formed with a fold width longer than the specified fold width L. In this embodiment, the non-folded section L' is three times the length of the fold width L, which is equivalent to skipping one fold.

[0076] By forming the non-folding section L' in this way, as shown in Figure 19, the folded bundle can be divided into two parts, folded bundle Pa and folded bundle Pb, and the number of folds can be performed to exceed the height Hmax of the folded bundle that can be transported within the paper folding device 100. The length of the non-folding section L' can also be set arbitrarily by the user.

[0077] The divided folded bundles Pa and Pb are ultimately folded by the user by hand to complete a single accordion-fold bundle. However, if creases (fold lines) are made on the unfolded section L' during the folding process, it will make the user's hand folding easier. This point will be explained later.

[0078] On the other hand, if the paper folding controller 10 determines to add a crease (fold line) based on the settings (Yes in step S111), it performs transport of the non-folded section L' (with crease addition operation) (step S112).

[0079] Figures 20 to 24 show the process of forming a non-folded section to which a crease (fold line) is added.

[0080] Figure 20 shows the point in time when the number of folds reaches the height Hmax of the folded stack that can be transported within the paper folding device 100, that is, when the folded stack reaches height H' and two creases Ca and Cb are about to be added at equal intervals above the unfolded section L'. At the point shown in Figure 20, the paper folding controller 10 rotates the transport roller pair 14 upwards and the folding roller pair 11 and folding roller pair 12 to the left, pulling the paper P upwards.

[0081] Figure 21 shows the point in time when a crease Cb is added to the non-folded section L'. As explained in Figure 20 above, the paper folding controller 10 pulls the paper P upwards. As a result, as shown in Figure 21, the current right-hand fold position moves away from the folding roller pair 12, and this becomes the crease Cb.

[0082] Figure 22 shows the point in time when the crease Ca is added to the non-folded section L'. The paper folding controller 10 continues to pull the paper P upward, as explained in Figure 21 above. As a result, as shown in Figure 22, the current left-side folding position moves away from the folding roller pair 8, and this becomes the crease Ca.

[0083] Figure 23 shows the point in time when the unfolded section L' is about to be formed, with two creases Ca and Cb added. As shown in Figure 23, after adding crease Ca as described in Figure 22, the paper folding controller 10 rotates the transport roller pair 14 downwards and the folding roller pair 12 to the right, transporting the paper P to the right.

[0084] Figure 24 shows the point in time after two creases Ca and Cb have been added to the non-folded section L'. As shown in Figure 24, it can be seen that two creases Ca and Cb have been added to the non-folded section L'.

[0085] Alternatively, instead of using the crease addition method described here (utilizing rotational control of each folding roller pair 11, 12), the unfolded section L' may be transported to the position shown in Figure 24 (or the folded bundle itself may be discharged from the paper folding device 100), and then creases Ca and Cb may be added retrofitted using existing crease addition means.

[0086] Here, Figure 25 is a cross-sectional view showing an example of a folded bundle formed by adding creases (fold lines) and dividing it. As shown in Figure 25, in order for the user to ultimately fold the two discharged folded bundles Pa and Pb together by hand into a single folded bundle, it is optimal to add two creases Ca and crease b. Specifically, if the non-folding section L' is three times the length of the folding width L, then the creases are placed at positions that divide the non-folding section L' into three equal parts, as shown in Figure 25. This makes it easier for the user to fold the two folded bundles Pa and Pb together by hand, and all the folding widths become the originally specified folding width L.

[0087] In the example shown in Figure 25, the position of the crease (fold line) is set to three times the length of the fold width L in order to maintain the appearance of an accordion fold. However, this is not the only option, and it is possible to adjust it depending on the purpose.

[0088] As described above, according to this embodiment, the number of folds required for the paper P to reach a height that makes it difficult to transport is specified, and the folded bundle is divided by skipping one fold before reaching the upper limit of the transportable height. As a result, the height of the folded bundle after the folding process is suppressed, preventing the bundle from getting caught in the transport path (such as the discharge port) and causing a paper jam, and also allowing for a higher number of transportable folds to be set than in conventional designs.

[0089] In this embodiment, an example of creating two folded bundles is shown, but it is not limited to this. Here, Figure 26 is a cross-sectional view showing another example of a folded bundle formed by adding creases and dividing it. Figure 26 shows an example of creating three folded bundles. As shown in Figures 13 to 15, in this embodiment, since the maximum number of folds that can be transported Nmax can be set to create an unfolded section L', there is no limit to the number of folded bundles. With the paper folding device 100 of this embodiment, folded bundles Pa, Pb, Pc, etc. can be continuously created.

[0090] The program executed by the paper folding device 100 of this embodiment is provided as a file in an installable or executable format, recorded on a computer-readable storage medium such as a CD-ROM, flexible disk (FD), CD-R, or DVD (Digital Versatile Disc).

[0091] Furthermore, the program executed by the paper folding device 100 of this embodiment may be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network. Alternatively, the program executed by the paper folding device 100 of this embodiment may be provided or distributed via a network such as the Internet.

[0092] Alternatively, the program executed by the paper folding device 100 of this embodiment may be pre-installed and provided in ROM or the like.

[0093] In the above embodiment, the image forming apparatus of the present invention is described using an example of application to a copier, but it is not limited to this, and can be applied to any image forming apparatus such as a multifunction device, printer, scanner, or facsimile device that has at least two functions from among copying, printing, scanning, and facsimile. [Explanation of Symbols]

[0094] 10 Control Unit 11,12 Folding roller pair 14 Conveyor roller pair 20,21 Guidance means 100 paper folding devices 200 Image forming apparatus [Prior art documents] [Patent Documents]

[0095] [Patent Document 1] Japanese Patent Application Publication No. 11-035229

Claims

1. A pair of transport rollers that can move the recording medium forward and backward, A plurality of folding roller pairs that transport the recording medium in a direction perpendicular to the direction in which the transport roller pair transports the recording medium, A pair of guiding means that perform a folding process in which the recording medium is guided into the nip of the folding roller pair and folded, while alternately switching the folding roller pair that guides the recording medium, A control unit that controls the folding roller pair, the transport roller pair, and the guidance means, and skips the folding process at least once when the number of folds of the folded bundle that has undergone the folding process reaches the maximum number of folds which is the upper limit of the transportable height, A paper folding device characterized by being equipped with the following features.

2. The control unit, by transporting the recording medium by the transport roller pair for a length longer than the specified folding width, creates a non-folding section where no folds are formed, and then resumes the remaining folding process at the specified folding width. The paper folding device according to feature 1.

3. The control unit creates the unfolded section multiple times and forms the folded bundle multiple times. The paper folding device according to feature 2.

4. The control unit can switch between automatically setting the maximum number of folds as the number of folds that can be transported, or setting it arbitrarily in advance by the user. A paper folding device according to any one of claims 1 to 3, characterized by the features described herein.

5. The control unit performs a crease process once or multiple times, creating fold lines at equal intervals or arbitrary intervals specified by the user on the non-folded section. The paper folding device according to claim 2 or 3.

6. Image forming apparatus and A paper folding device according to any one of claims 1 to 5, An image forming system characterized by comprising the following features.

Images