Marking device and image forming apparatus

Abstract

To provide a marking device capable of optimizing a marker length by changing the marker length according to a sheet width size.SOLUTION: In the marking device 33A that conveys the sheets S stacked on the sheet stacker 14 so as to sequentially place the markers 34 on the uppermost sheet S stacked on the sheet stacker 14 such that an arbitrary sheet bundle interval is obtained in the sheet widthwise length orthogonal to the sheet conveying length of the sheets S stacked on the sheet stacker 14, the marking device 33A acquires the sheet widthwise length information from the storage unit 65 that stores the sheet conveying length information and the sheet widthwise length information, and changes / delays the marker conveyance end timing of the marker 34 fed from the marking device 33A according to the acquired sheet widthwise length information as illustrated in FIG. 12. The marker conveyance end timing is delayed as the sheet width and length information is longer, and is advanced as the sheet width and length information is shorter.SELECTED DRAWING: Figure 12

Description

[Technical Field]

[0001] The present invention relates to a marking device and an image forming device. [Background technology]

[0002] In a printing device or an electrophotographic image forming device, printed sheets or sheets with images formed thereon (hereinafter simply referred to as "sheets") are sequentially stacked on a stacking table. A known sorting device marks specific boundaries of a stack of sheets (hereinafter also referred to as a "stacked sheet stack") by inserting sheet-shaped sorting tape (hereinafter referred to as a "marker") into a stack of sheets (hereinafter also referred to as a "stacked sheet stack") consisting of multiple sheets stacked on the stacking table so that the tape extends beyond the edge of the stacked sheet stack in the sheet width direction for each desired number of sheets (see, for example, Patent Document 1). In the present invention, such a sorting device is referred to as a marking device.

[0003] In such conventional marking devices, as shown in Figures 16(a) and 16(b), if the conventional marking device 33 is of a fixed position type, the following issues arise depending on the sheet size (sheet width length Wp perpendicular to the sheet conveying length) of the sheets S loaded on the loading tray 14. 16(a) and 16(b) are views viewed from the downstream side in the sheet conveyance direction, and as indicated by the hatching on the outer wall of the marking device 33, the marking device 33 is installed in a fixed position on the device body side of the sheet stacking device 8 shown in FIG. 1, which will be described later. On the left side of the marking device 33 in the figure, a stacking table 14 that can move in the vertical direction and that carries printed sheets S is disposed. The stacking table 14 is controlled, as will be described later, so that the uppermost sheet S on the stacking table 14 occupies a constant height position. Also, above the uppermost sheet S on the stacking table 14, as shown in FIG. 8, which will be described later, a drive roller 20, a driven roller 21, conveyor belts 22a and 22b, a holding member 23, etc. are shown; however, in order to explain issues specific to the marking device 33, these components are not shown. The internal mechanical configuration of the marking device 33 is the same as that of the marking device 33 shown in FIGS. 8 and 10 to which the present invention is applied, which will be described later, and therefore is not shown.

[0004] 16(a), the first problem occurs when the sheet width Wp of the sheets S (hereinafter also referred to as the "stacked sheet stack S") stacked on the stacking table 14 is relatively smaller than the sheet width Wp shown in FIG. 16(b). If this is too small, the distance D between the sheet edge Sb of the stacked sheet stack S at the sheet width Wp and the marker discharge port 35a of the marking device 33 becomes large. As a result, the marker 34 (shown by the dashed line in the figure) cut by the cutter 40 (see FIG. 10) of the marking device 33 and ejected from the marker discharge port 35a in the marker ejection direction AM will not be stacked on the topmost sheet S stacked on the stacking table 14 but will fall and land sequentially as shown by the arrow, making it impossible to achieve the purpose of inserting the marker 34.

[0005] The second problem occurs when, as shown in Fig. 16(b), the sheet width Wp of the stack of sheets S stacked on the stacking table 14 is relatively larger than the sheet width Wp shown in Fig. 16(a), and if it is too large, the distance D between the sheet edge Sb of the stack of sheets S at the sheet width Wp and the marker discharge port 35a of the marking device 33 becomes small. As a result, the marking device 33 ejects and outputs markers 34 that are several times longer than the length of the markers 34 that are actually required, as shown by the dashed line in the figure, and the amount of markers 34 consumed increases. Summary of the Invention [Problem to be solved by the invention]

[0006] To provide a marking device capable of optimizing the marker length according to the sheet width size. [Means for solving the problem]

[0007] The invention described in claim 1 is a marking device that transports markers to be placed sequentially on the topmost sheet stacked on a stacking table so that the sheet stack has an arbitrary spacing between the sheet stacks in a sheet width length perpendicular to the sheet transport length of the sheet stack stacked on the stacking table, and has a sheet size information storage means that stores sheet transport length information and sheet width length information, and the marking device acquires the sheet width length information from the sheet size information storage means and delays the timing of the end of marker transport in accordance with the acquired sheet width length information. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a marking device that can optimize the marker length according to the sheet width size. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic front view of an image forming apparatus to which an embodiment of the present invention can be applied; [Figure 2] FIG. 2 is a schematic front view showing the sheet stacking device in which the holding member is in a standby position. [Figure 3] 10 is a schematic plan view showing the sheet stacking device in which the holding member is in a standby position; [Figure 4] FIG. 2 is a schematic view of a lifting device used in the sheet stacking device. [Figure 5] 10 is a schematic front view of the sheet stacking device showing a state in which the leading edge of the transfer sheet has entered the holding member by a predetermined amount. FIG. [Figure 6] 10 is a schematic front view of the sheet stacking device showing a state in which the transfer sheet has been released from the holding member. FIG. [Figure 7] 10 is a schematic front view of the sheet stacking device showing a state in which the small-sized transfer sheet has been released from the holding member. FIG. [Figure 8] FIG. 2 is a schematic side view of a sheet stacking device equipped with a marking device. [Figure 9] FIG. 2 is a schematic front view of a sheet stacking device equipped with a marking device. [Figure 10] FIG. 2 is a schematic diagram illustrating a marking device. [Figure 11] 1 is a functional block diagram of a marking device according to an embodiment of the present invention. [Figure 12] 10A and 10B are diagrams illustrating an operation sequence of the marking device according to an embodiment. [Figure 13] FIG. 10 is an explanatory diagram of the positional relationship of markers for explaining the timing of marker transport completion. [Figure 14] 10 is a flowchart including an operation flow of a marking device according to an embodiment. [Figure 15] 10A and 10B are explanatory diagrams illustrating the effects obtained by the marking device according to one embodiment. [Figure 16] FIG. 1 is a diagram illustrating a conventional problem. [Figure 17] FIG. 10 is a diagram showing an example of an operation sequence of a conventional marking device. DETAILED DESCRIPTION OF THE INVENTION

[0010] Fig. 1 shows an image forming apparatus to which one embodiment of the present invention can be applied. In the figure, the image forming apparatus 1 has a sheet feeder 2 in which sheets S, which are recording media, are stored, a sheet position correction device 3 that corrects the position of the sheets S, and an imaging device 4 that forms an image on the sheets S. In Fig. 1 and other figures, the symbol X represents the sheet conveyance direction, the symbol Y represents the sheet width direction perpendicular to the sheet conveyance direction X, and the symbol Z represents the up-down direction (height direction) perpendicular to the sheet conveyance direction X and the sheet width direction Y. The image forming apparatus 1 further includes a sheet drying device 5 for drying the formed image, a sheet cooling device 6 for cooling the sheet S, a sheet inverting device 7 for inverting the sheet S, a first sheet stacking device 8 and a second sheet stacking device 9 for stacking the sheet S as the sheet stacking device of the present invention, and an operation unit 10 for controlling each of the above-mentioned parts based on user instructions.

[0011] The sheet feeding device 2 and the sheet position correction device 3 are devices that convey sheets S that have been previously stacked and stored one by one, and the sheet feeding device 2 is provided with a sheet size detection sensor 11 that detects the size of the fed sheet S. A plurality of sheet size detection sensors 11 are provided to detect the length and width of the sheet S. The sheet position correction device 3 adjusts the timing of conveying the sheet S based on the sheet size information sent from the sheet size detection sensor 11 so that the image forming device 4 forms an image on the sheet S at a predetermined position.

[0012] In this embodiment, the image forming device 4 is an inkjet recording device that ejects ink of each color, black (K), cyan (C), magenta (M), and yellow (Y), to form a full-color image on the sheet S. The image forming device 4 has liquid ejection devices 13K, 13C, 13M, and 13Y that eject the above-mentioned color inks arranged around the main drum roll 12, and forms inkjet images of each color on the sheet S. The sheet drying device 5 and the sheet cooling device 6 dry the inkjet image formed on the sheet S and then cool it, thereby allowing the inkjet image to be stably maintained on the sheet S.

[0013] The sheet inverting device 7 inverts the sheet S by a switchback method as necessary and retransports it to the sheet position correcting device 3, thereby switching the image forming surface of the sheet S, i.e., the surface facing the drum roll 12. The above-mentioned components are appropriately controlled in response to user operations via the operation unit 10, and an inkjet image is formed on the sheet S. In this embodiment, an inkjet printer that forms inkjet images has been described as the image forming apparatus 1, but the image forming apparatus is not limited to this and may be an image forming apparatus having an electrophotographic image forming unit as the imaging device 4. In this case, a fixing device that fixes the toner image onto the sheet S may be provided instead of the sheet drying device 5 and the sheet cooling device 6. The configuration of each part within such an image forming apparatus 1 may be the same as that of a conventional image forming apparatus, and detailed description of each part will be omitted.

[0014] Next, we will explain the first sheet stacking device 8. The first sheet stacking device 8 and the second sheet stacking device 9 are both discharge destinations of sheets S in the image forming apparatus 1, and may have the same configuration or different configurations. In this embodiment, the first sheet stacking device 8 and the second sheet stacking device 9 have the same configuration, and only the sheet discharge destinations are different. 2 includes a loading platform 14 also called a sheet tray, a sheet transport mechanism 15 that transports the sheet S to the loading platform 14, and a guide mechanism 16 that grips the leading edge of the sheet S transported toward the loading platform 14 and transports it downstream in the transport direction. The first sheet stacking device 8 also includes a trigger sensor 17 that is a sheet leading edge detection sensor that detects the leading edge of the sheet S on the upstream side of the sheet transport mechanism 15 in the sheet transport direction. The first sheet stacking device 8 also includes a bypass transport path 18 that transports the transported sheet S around the loading platform 14 to a second sheet stacking device 9 located downstream of the first sheet stacking device 8 in the sheet transport direction.

[0015] The stacking tray 14 on which the sheets S after image formation are stacked is initially positioned below the sheets S fed by the sheet conveying mechanism 15, and moves downward as the sheets S are stacked on the stacking tray 14, so that the position of the top surface of the stacked sheet stack is maintained at a height that makes it easy to stack the sheets S discharged from the sheet conveying mechanism 15. The lifting device that raises and lowers the stacking tray 14 will be described later. The sheets S stacked on the stacking tray 14 are removed by the user by pulling out the stacking tray 14 from the first sheet stacking device 8. The sheet transport mechanism 15, which transports the sheet S transported from the image forming device 4 toward the stacking table 14, is a well-known roller pair consisting of a drive roller 15a and a driven roller 15b. The sheet transport mechanism 15 receives the sheet S discharged by a supply roller 19 disposed at the most upstream position in the sheet transport direction of the first sheet stacking device 8, and transports it downstream in the sheet transport direction. The trigger sensor 17 is disposed upstream of the sheet transport mechanism 15 in the sheet transport direction, and detects the leading edge of the sheet S being transported and outputs a signal.

[0016] The guide mechanism 16, which is disposed downstream of the sheet conveying mechanism 15 in the sheet conveying direction, holds the leading edge of the sheet S conveyed by the sheet conveying mechanism 15 and conveys the sheet S in the sheet conveying direction at a speed faster than the sheet conveying speed of the sheet conveying mechanism 15. The guide mechanism 16 holds the leading edge of the sheet S and moves away from the leading edge of the sheet S at a release position, thereby functioning as a guide member that guides the conveyed sheet S onto the stacking table 14. The guide mechanism 16 has a runnable endless conveyor belt 22 stretched over a drive roller 20 and a driven roller 21, and a holding member 23 attached to the conveyor belt 22 and moving as the conveyor belt 22 runs. The running speed of the conveyor belt 22 is made variable by a motor 24, which is a variable speed stepping motor that drives the drive roller 20, and the position of the holding member 23 on the conveyor belt 22 can be determined based on the number of steps. 3, four conveyor belts 22 are arranged parallel to each other in the sheet width direction indicated by the symbol B, which is the width direction of the sheet S, and two holding members 23 are provided on each of the conveyor belts 22a, 22b, 22b, 22a, and are arranged at positions point-symmetrical with each other in the circumferential direction of the conveyor belt 22. The holding members 23 are attached to the outer side in the circumferential direction of the conveyor belt 22 and move as the conveyor belt 22 travels. In FIG. 3, the symbol A indicates the sheet conveying direction.

[0017] The first sheet stacking device 8 uses the speed difference between the sheet conveying speed of the sheet conveying mechanism 15 and the sheet conveying speed of the guide mechanism 16 to detach the sheet S held by the holding member 23 from the holding member 23 and stack the detached sheet S on the stacking table 14. A blower fan 25 is provided at a location downstream in the sheet conveying direction of the guide mechanism 16, which applies an air flow to the conveyed sheet S in a direction toward the top of the stacking table 14, i.e., a direction toward the downward side. The blower fan 25 is always in operation, and applies an air flow to the sheet S held by the holding member 23 so as to press the sheet S against the stacking table 14.

[0018] 2, holding member 23 has opening 23a through which the leading edge of sheet S is inserted, and clamping portion 23b that clamps the leading edge of sheet S inserted through opening 23a. The force with which clamping portion 23b clamps the leading edge of sheet S is set to be smaller than the frictional force between sheet conveying mechanism 15 and sheet S. As a result, clamping portion 23b allows sheet S, which has been conveyed by sheet conveying mechanism 15 and inserted through opening 23a, to enter holding member 23, which is stopped at the standby position shown in FIG. 2, due to the rigidity of sheet S, and holds the entered sheet S with its elasticity. The contact surface of the holding member 23 with the sheet S is preferably made of a highly smooth material such as metal or resin, so that the sheet S can be smoothly held by the holding member 23.

[0019] 2 when the sheet S is received, the holding member 23 is stopped at the standby position shown in Fig. 2, and the leading edge of the sheet S is detected by the trigger sensor 17, and after the leading edge of the sheet S is clamped by the clamping portion 23b, the holding member 23 starts conveying the sheet S at a predetermined timing. In this way, the holding member 23 holds the leading edge of the sheet S conveyed by the sheet conveying mechanism 15 at the standby position, and then moves in the sheet conveying direction to function as a guide member that guides the conveyance of the sheet S. 2 and 3, in the image forming apparatus 1, two holding members 23 are arranged on the outer peripheral surface of the conveyor belt 22, with their phases shifted by 180 degrees from each other. Therefore, when one holding member 23 completes conveying the sheet S, it moves half a revolution as the conveyor belt 22 moves, and the other holding member 23 stops at the standby position. In this way, by alternately moving the two holding members 23 to the standby position, the time it takes for the holding members 23 to return to the standby position is shortened, and the conveyance cycle of the sheet S can be improved.

[0020] 3, in the image forming apparatus 1, four conveyor belts 22 are provided in the sheet width direction, and two holding members 23 are arranged on each of the conveyor belts 22. As a result, compared to a configuration in which one or two conveyor belts 22 are provided and two holding members 23 are provided per belt, the holding members 23 can be made smaller, reducing the inertial load when the conveyor belt 22 is running, and increasing the number of holding members 23 makes it possible to stabilize the holding posture of the sheet S.

[0021] The four conveyor belts 22a, 22b, 22b, 22a are classified into end belts 22a, 22a located at each end in the sheet width direction, and central belts 22b, 22b located between the end belts 22a, 22a. The holding members 23 of the end belts 22a, 22a and the central belts 22b, 22b are arranged so that their attachment positions in the sheet conveying direction are different from each other. Specifically, the holding members 23 of the central belts 22b, 22b are positioned upstream in the sheet conveying direction compared to the holding members 23 of the end belts 22a, 22a. With the above-described configuration, the timing at which the sheet S is held by the holding members 23 can be shifted between the end-side belts 22a and the center-side belts 22b, thereby reducing the load on the sheet S when it enters the holding members 23. In addition, the timing at which the sheet S leaves the holding members 23 is also shifted, so the sheet S can be maintained in a stable position.

[0022] As shown in Fig. 3, the sheet transport mechanism 15 is composed of two pairs of rollers, each of which has a drive roller 15a and a driven roller 15b, and each pair of rollers is configured in a striped manner so as to be positioned between each of the transport belts 22a, 22b, 22b, 22a. In Fig. 3, the drive roller 15a is disposed on the upper side of the sheet S, and the driven roller 15b is disposed on the lower side of the sheet S, but the configuration is not limited to this.

[0023] Next, a description will be given of the lifting device that raises and lowers the loading table 14. As shown in Fig. 4, the loading table 14 has a stack of sheets S loaded thereon via a pallet 26, and the loading table 14 is configured to be able to be raised and lowered by a lifting device 27. The lifting device 27 includes a pair of pulleys 28a, 28b, a pair of chains 29a, 29b, a pair of weights 30a, 30b, an upper limit detection sensor 31, and a lower limit detection sensor 32. Note that the sheets S may be placed directly on the loading table 14 without using the pallet 26. The pair of pulleys 28a, 28b are rotatably supported on the housing of the image forming apparatus 1 at positions above the loading platform 14 and spaced apart from each other in the sheet conveying direction indicated by the symbol A. A pair of chains 29a, 29b are stretched over the corresponding pulleys 28a, 28b, and one end is connected to the loading platform 14 and the other end is connected to the corresponding weights 30a, 30b, respectively. When the pulleys 28a and 28b rotate in a first direction (in FIG. 4, the pulley 28a rotates clockwise and the pulley 28b rotates counterclockwise), the loading platform 14 rises and the weights 30a and 30b fall. On the other hand, when the pulleys 28a and 28b rotate in a second direction opposite to the first direction (in FIG. 4, the pulley 28a rotates counterclockwise and the pulley 28b rotates clockwise), the loading platform 14 falls and the weights 30a and 30b rise.

[0024] The upper limit detection sensor 31 detects whether the top sheet S stacked on the stacking table 14 has reached the upper limit position, which is the limit position to which the sheet S can be raised by the lifting device 27. The upper limit detection sensor 31, which is disposed above the stacking table 14, is a reflective optical sensor that includes, for example, a light-emitting unit that emits light and a light-receiving unit that receives light that is output from the light-emitting unit and reflected by the sheet S. The upper limit detection sensor 31 outputs a detection signal to a control means (not shown) when a sheet S is present on the detection optical path, i.e., when the uppermost sheet S stacked on the stacking tray 14 reaches the upper limit position. On the other hand, the upper limit detection sensor 31 does not output a detection signal when a sheet S is not present on the detection optical path. The upper limit detection sensor 31 may be a reflective or transmissive optical sensor. When the control means (not shown) receives the upper limit position detection signal, it immediately stops the lifting operation of the stacking tray 14.

[0025] The lower limit detection sensor 32 detects whether the maximum capacity of sheets S is stacked on the stacking tray 14 and whether the stacking tray 14 has reached the lowest position, which is the limit position to which the stacking tray 14 is allowed to descend. The lower limit detection sensor 32, which is located at a position facing the weight 30b when the stacking tray 14 is fully loaded, is, for example, a reflective optical sensor similar to the upper limit detection sensor 31. The lower limit detection sensor 32 outputs a detection signal to a control means (not shown) when the loading platform 14 is present on the detection optical path, i.e., when the loading platform 14 is fully loaded and reaches the lower limit position. On the other hand, the lower limit detection sensor 32 does not output a detection signal when the loading platform 14 is not present on the detection optical path. The lower limit detection sensor 32 may be a reflective or transmissive optical sensor. When the control means (not shown) receives a detection signal indicating the lower limit position, it immediately stops the lowering operation of the loading platform 14.

[0026] Next, we will explain the sheet conveying process by the above-mentioned first sheet stacking device 8. Note that since the stacking of sheets S in the first sheet stacking device 8 and the stacking of sheets S in the second sheet stacking device 9 can be achieved by the same configuration and control, only the first sheet stacking device 8 will be explained here. First, the first sheet stacking device 8 acquires length information of the sheet S to be transported and stacked. Specifically, the size information used is based on the length and width of the sheet S detected by the sheet size detection sensor 11, or the size information of the sheet S input by the user via the operation unit 10. Next, as the sheet feeding device 2, the sheet position correction device 3, and the imaging device 4 are driven, the sheet S on which an image has been formed is transported to the first sheet stacking device 8, and the supply roller 19 starts transporting the sheet S sent after the image has been formed by the imaging device 4, and the sheet transport mechanism 15 is driven. At this time, the guide mechanism 16 is stopped in the standby state shown in FIG. 2 where the holding member 23 is stopped at the standby position, and the blower fan 25 starts operating to always maintain a constant air volume.

[0027] Thereafter, it is determined whether the trigger sensor 17 has detected the leading edge of the sheet S, and if it is determined that the leading edge of the sheet S has been detected, a first predetermined time is measured, which is the elapsed time starting from the time when the leading edge of the sheet S was detected. This first predetermined time is determined in advance according to the size of the sheet S to be conveyed. When the first predetermined time has elapsed, the conveyor belt 22 starts to run, and the holding member 23, which has been stopped at the standby position, starts to move in the sheet conveying direction. At this time, because the conveying speed of the sheet S by the sheet conveying mechanism 15 is faster than the moving speed of the holding member 23, the leading edge of the sheet S enters the holding member 23 through the opening 23a, and the entered leading edge is clamped and held by the clamping portion 23b. The movement speed of the holding member 23, i.e., the drive speed of the motor 24 that drives the conveyor belt 22, is controlled by a control means (not shown) so that the conveyance speed of the sheet S by the sheet conveying mechanism 15 and the movement speed of the holding member 23 are equal when the entry of the sheet S into the holding member 23 is complete. In this way, the leading edge of the sheet S enters the inside of the holding member 23 due to the speed difference until the movement speed of the holding member 23 becomes equal to the conveyance speed of the sheet S by the sheet conveying mechanism 15. The time from when the holding member 23 starts to move to when the entry of the sheet S into the holding member 23 is complete is the second predetermined time. The amount of entry of the leading edge of the sheet S into the holding member 23 corresponding to the first and second predetermined times at this time is the predetermined amount C shown in FIG. 5.

[0028] When the holding member 23 holds the sheet S, that is, when the leading edge of the sheet S has penetrated the holding member 23 by a predetermined amount C, a first acceleration is performed on the movement speed of the holding member 23, and a third predetermined time period is measured according to previously acquired size information of the sheet S. The sheet conveying mechanism 15 and the guide mechanism 16 start conveying and moving the sheet S using the speed difference between the conveying speed of the sheet S by the sheet conveying mechanism 15 and the moving speed of the holding member 23, which is generated by the first acceleration. At this time, the movement speed of the holding member 23 becomes faster than the conveying speed of the sheet S by the sheet conveying mechanism 15, and the holding member 23 pulls the leading edge of the sheet S while conveying it. This prevents the sheet S from bending compared to when the conveying speed is constant. During this conveyance, the force with which the holding member 23 holds the sheet S is smaller than the frictional force between the sheet conveying mechanism 15 and the sheet S, so the sheet S gradually releases from the holding member 23. However, the holding state of the sheet S by the holding member 23 is maintained from the position where the sheet S was held to the position where the sheet S is released.

[0029] When a third predetermined time has elapsed since the holding member 23 held the sheet S, a second acceleration is performed in the movement speed of the holding member 23, and the movement speed of the holding member 23 is further accelerated, causing the sheet S to separate from the holding member 23. Even if the sheet S comes out of the sheet conveying mechanism 15 before it separates from the holding member 23, the inertial force of the sheet S causes the sheet S to separate from the holding member 23. Figure 6 shows the state when the sheet S has been separated from the holding member 23. In Figure 6, the symbol D indicates the acceleration position, which is the position of the holding member 23 where the second acceleration is performed, and the symbol E indicates the separation position, which is the position of the holding member 23 where the sheet S is separated.

[0030] 7 shows a case where a small-sized sheet S1, which is smaller than the sheet S, is used instead of the sheet S. As shown in Fig. 7, a control means (not shown) adjusts the acceleration position D and the release position E in accordance with the small-sized sheet S1, and the small-sized sheet S1 is released from the holding member 23 due to the speed difference between the conveying speed of the sheet S by the sheet conveying mechanism 15 caused by the second acceleration and the moving speed of the holding member 23. The sheet S or small size sheet S1 that has left the sheet transport mechanism 15 and separated from the holding member 23 receives wind force from the blower fan 25 and falls toward the stacking table 14, where it is stacked.

[0031] When the sheet S or small-size sheet S1 is released from the holding member 23, a fourth predetermined time is counted according to the previously acquired size information of the sheet S or small-size sheet S1, and when the fourth predetermined time has elapsed, the holding member 23 begins to decelerate and stops at the standby position. Thereafter, it is determined whether the image forming operation in the imaging device 4 is complete, and if it is determined that it is not complete, it is determined whether the trigger sensor 17 has detected the leading edge of the sheet S, and the above-mentioned operation is repeated until the image forming operation is complete. If it is determined that it is complete, the operation of the conveying member 6 and the blower fan 15 is stopped.

[0032] 8 shows the stacking table 14 of the first sheet stacking device 8 as viewed from the downstream side toward the upstream side in the sheet conveyance direction. In the figure, a marking device 33 is disposed in a fixed position on the right side of the stacking table 14, i.e., on the front side of the image forming apparatus 1. As shown in FIG. 8, the marking device 33 is a device that forms specific divisions in the stack of sheets S by inserting thin sheet-like bookmarks 34 into the sheets S stacked on the stacking table 14 for every arbitrary number of sheets to be managed, so that the markers protrude from the stack of sheets. 9, the marking device 33 is disposed at a position near the downstream end in the sheet conveying direction of the sheets S loaded on the stacking table 14. This is because if the marking device 33 is disposed near the upstream end in the sheet conveying direction of the sheets S loaded on the stacking table 14, when the sheets S being conveyed are not loaded on the stacking table 14 from directly above but are loaded at a speed in the sheet conveying direction, the sheets S may move the markers 34, causing the markers 34 to fall. The marking device 33 will be described below with reference to FIG. 10.

[0033] 10, the marking device 33 has a marker storage unit 35 that stores a continuous roll of markers 34 used when sorting sheets S based on image formation information set in the image forming apparatus 1, and a marker transport unit 36 ​​that transports the markers 34 from the marker storage unit 35 to the outside. The roll of markers 34 is supported by a marker support shaft 35b provided in the marker storage unit 35 so as to be rotatable and capable of unwinding the markers 34. The marker storage unit 35 has a sealed box shape and has an outlet 35a on one side for discharging the markers 34 to the outside. The marker conveying section 36 includes a roller pair 37 having a drive roller 37a and a driven roller 37b that sandwich and convey the marker 34, and a tension roller 38 that applies tension to the marker 34. The drive roller 37a, which has a V-groove on its circumferential surface, is driven to rotate by a motor 39 (described later), and the driven roller 37b, which has an outer shape that fits into the V-groove of the drive roller 37a, rotates in response to the rotation of the drive roller 37a. The tension roller 38, which is biased by a biasing means (not shown) and applies a predetermined tension to the marker 34, also rotates in response to the movement of the marker 34 as it is sandwiched and conveyed by the roller pair 37. With this configuration, the marker 34 that has passed the roller pair 37 forms a crease with a V-shaped cross section, and the marker 34 does not bend even after leaving the roller pair 37, maintaining its straightness.

[0034] A cutter 40 is provided between the roller pair 37 and the discharge port 35a to cut the markers 34 that are discharged to the outside through the discharge port 35a. The cutter 40 has a fixed blade 40a arranged above the passing markers 34 and a movable blade 40b arranged below the passing markers 34. The movable blade 40b is moved upward by a motor 39, which will be described later, and cuts the markers 34 by pinching them between itself and the fixed blade 40a. A motor 39 that drives both the drive roller 37a and the movable blade 40b is disposed inside the marker storage unit 35. The motor 39 can rotate in both forward and reverse directions, and is drivingly connected to the drive roller 37a and the movable blade 40b via a one-way clutch (not shown).When the motor 39 operates in either the forward or reverse drive state, it drives and rotates the drive roller 37a, and when the motor 39 operates in the other drive state, it drives and rotates the movable blade 40b so as to move it.

[0035] (Embodiment) An embodiment of the present invention will be described with reference to Fig. 11 and Fig. 12. Fig. 11 is a functional block diagram of a marking device according to the embodiment of the present invention, and Fig. 12 is a diagram showing an operation sequence of the marking device according to the embodiment. The marking device 33A shown in Fig. 11 has the same mechanical configuration as the conventional marking device 33 to which the present invention is applied and shown in Fig. 8 to Fig. 10, except that some of the control function configuration described below has been added or changed. The control function configuration of the marking device 33A includes a condition acquisition unit 62, a marker transport time determination unit 63, a control unit 64, and a memory unit 65.

[0036] 11, a condition acquisition unit 62 acquires printing conditions and acquired values ​​of the trigger sensor 17 (see FIG. 2). A marker transport time determination unit 63 has a function of calculating the marker transport time from a formula based on the printing conditions and reading out the marker transport time corresponding to the printing conditions from a memory unit 65 described below. A control unit 64 has a function of controlling a motor 39 that is used for both transporting and cutting the marker 34. The memory unit 65 has a function of storing the marker transport time or a function used to calculate the marker transport time, as well as setting values. The control device of the marking device 33A may be configured to include, in addition to a condition acquisition unit 62, a marker transport time determination unit 63, a control unit 64, and a memory unit 65, a microcomputer equipped with, for example, a CPU, RAM, ROM, a timer, etc. (not shown).

[0037] In addition to the above functions, the storage unit 65 may also have a function as sheet size information storage means for storing sheet size information (sheet transport length information and sheet width length information) of sheets transported and stacked on the first sheet stacking device 8 and the second sheet stacking device 9. Furthermore, without being limited to this, the storage unit 65 may also have a function as sheet size information storage means for storing sheet size information transmitted from various control units provided in the sheet feeding device 2, the imaging device 3, etc. that constitute the device system of the image forming apparatus 1 in FIG.

[0038] The sheet width information of the sheet size information (sheet conveyance length information and sheet width information) is not limited to the above, and size information of the sheet S input by the user from the operation unit 10 may be used.

[0039] The greatest feature of the marking device 33A of this embodiment is that it changes the marker conveyance end timing of the marker 34 fed out from the marking device 33A, as shown in Figure 12, depending on the sheet width length information among the sheet size information acquired by the memory unit 65.

[0040] The operation sequence of the marking device 33A shown in Fig. 12 will be explained while comparing it with the operation sequence of the conventional marking device 33 shown in Fig. 17. In Fig. 12 and Fig. 17, the trigger sensor 17, the transport timer 41, the cut timer 42, the marker transport timer 43, and the marker cut timer 44 are arranged vertically to explain the operation sequence. The trigger sensor 17 (see FIGS. 2 and 9) that monitors the timing of the arrival or passing of a sheet at a given position is used as a start trigger, and the transport timer 41 and cut timer 42 are started by the detection of the trigger sensor 17, which is the same for both the marking devices 33 and 33A. On the other hand, the timing after the start of transport of the marker 34 by the marker transport timer 43 differs between the marking devices 33 and 33A, and will be described later. The marker cut timer 44 starts cutting the marker when it has run a specified amount, and the marker 34 is output.

[0041] 12 is a timer for ensuring the time from when the trigger sensor 17, which detects the leading edge of a sheet upstream of the transport path, detects the leading edge of the sheet until the marking device 33, 33A starts transporting the marker 34, and has a specified amount only during High (1). In other words, since it takes time from when the trigger sensor 17 detects the leading edge of the sheet until the sheet is discharged and stacked on the stacking tray 14, by starting transport of the marker 34 after the time set in the transport timer 41 has elapsed (after the sheet is reliably stacked on the stacking tray 14), the marker 34 can be reliably placed on the sheet discharged and stacked on the stacking tray 14. The time of the transport timer 41 may be set according to the printing speed.

[0042] The cut timer 42 is a timer for ensuring the time from when the leading edge of the sheet is detected by the trigger sensor 17 until the marker is cut, and the marker is cut after the time set in the cut timer 42 has elapsed (after the leading edge of the sheet is detected by the trigger sensor 17, the sheet is discharged and stacked on the stacking tray 14, and the marker transport is completed), thereby ensuring that the marker 34 is placed on the top surface of the stacked sheets. The time of the cut timer 42 may be set according to the printing speed.

[0043] The marker transport timer 43 is a timer that indicates the drive timing of the forward rotation of the motor 39 (which serves both to transport the marker and to cut the marker) for transporting the marker 34, and the marker 34 is transported only while the timer is set to High (1). After the time set by the marker transport timer 43 has elapsed, the timer switches from Low (0) to High (1), and maintains High (1) for the time indicated by the marker transport time tm.

[0044] In the operation sequence of the marking device 33 shown in Figure 17, the marker 34 starts to be transported when the marker transport timer 43 has run a specified amount, whereas in the operation sequence of the marking device 33A in Figure 12, the marker 34 starts to be transported when the marker transport timer 43 has run an amount corresponding to the sheet size (sheet width length), and the marker transport time tm described below varies, which is a major difference. Thus, when comparing the operation sequence of the marking device 33A in FIG. 12 with the operation sequence of the marking device 33 shown in FIG. 17, the contents set by the marker transport timer 43 are significantly different, but the other contents are the same.

[0045] The marker cut timer 44 is a timer that indicates the drive timing of the dual-purpose motor 39 for cutting the marker, and when it reaches High (1), it reverses the rotation of the motor 39 (which is used for both marker transport and marker cutting) to drive the cutter 40. After the time set in the marker cut timer 44 has elapsed, it switches from Low (0) to High (1) and maintains High (1) for the time required to cut the marker.

[0046] The timing of cutting the marker is fixed regardless of the sheet width. In other words, the length of the marker 34 can be controlled by controlling only the marker transport time. Note that even if the cutting timing is fixed regardless of the sheet width, it may be variable depending on the printing speed. In other words, the cutting timing (cut timer time) for a first printing speed (high-speed printing) may be set earlier (shorter) than the cutting timing (cut timer time) for a second printing speed (slow-speed printing) that is slower than the first printing speed.

[0047] The timing of marker transport end will be described with reference to Figure 13. Figure 13 is an explanatory diagram of the marker positional relationship for explaining the timing of marker transport end. For simplicity, Figure 13 does not show the marker transport unit 35, drive roller 37a, driven roller 37b, motor 39, and other components provided in the marking device 33A. In Figure 13, arrow AM indicates the marker injection direction, which is perpendicular to the sheet transport direction. The timing of marker conveyance completion is defined as a function of the sheet width length, as will be described later. At this time, it is set so that the marker gravity center g (located at a position half the length of the marker 34) is reliably placed at the sheet stacking position (a position on the sheets S stacked on the stacking table 14).

[0048] The marker transport time tm is defined as a function of the sheet width Wp by the following formula (1). TIFF2026003523000002.tif12150In the above formula (1), the meaning of each symbol is as follows. tm: Marker transport time Wp: Sheet width and length x: Distance from the center of the sheet transport to the cutter of the marking device vm: Marker transport speed R: Marker loading ratio (length of marker on stack of loaded sheets / total length of marker)

[0049] Here, the sheet width Wp is information determined by a sheet size setting included in user settings indicating printing conditions accepted by the image forming apparatus 1 from a user. For example, the image forming apparatus 1 can store information on the sheet width Wp for each sheet size printable by the image forming apparatus 1, and can read out information on the sheet width Wp corresponding to the sheet size setting selected by the user from an operation unit 10 provided in the image forming apparatus 1 (or an external terminal via a network) and transmit the information to the marking device 33A. However, the marking device 33A may be configured to store information on the sheet width Wp for each sheet size, and accept the sheet size setting selected by the user from the image forming apparatus 1, thereby reading out information on the sheet width Wp corresponding to the sheet size setting.

[0050] The marker transport speed vm can be constant regardless of the user settings, but is not limited to this. For example, it may be determined based on the print speed setting included in the user settings received by the image forming apparatus 1 from the user. In other words, the marker transport speed for the first print speed (high-speed printing) can be set higher than the marker transport speed for the second print speed (low-speed printing), which is slower than the first print speed. In this case, the image forming apparatus 1 can store information on the marker transport speed vm for each printing speed at which the image forming apparatus 1 can print, and can read out information on the marker transport speed vm corresponding to the printing speed setting selected by the user from the operation unit 10 provided in the image forming apparatus 1 (or an external terminal via a network) and transmit it to the marking device 33A. However, it is also possible to store information on the marker transport speed vm for each printing speed in the marking device 33A, and read out information on the marker transport speed vm corresponding to the printing speed setting by accepting the printing speed setting selected by the user from the image forming apparatus 1. The distance x from the center of the sheet conveyance to the cutter of the marking device can be set constant regardless of the user setting.

[0051] The marker loading ratio R can be constant regardless of the user settings, but is not limited to this. For example, it may be determined based on the sheet size setting included in the user settings received from the user by the image forming apparatus 1. In this case, the image forming apparatus 1 can store information on the marker loading ratio R for each sheet size printable by the image forming apparatus 1, and can read out information on the marker loading ratio R corresponding to the sheet size setting selected by the user from the operation unit 10 provided in the image forming apparatus 1 (or an external terminal via a network) and transmit it to the marking device 33A. However, the marking device 33A may store information on the marker loading ratio R for each sheet size, and may read out information on the marker loading ratio R corresponding to the sheet size setting by receiving a sheet size setting selected by the user from the image forming device. Details of the method for determining the marker loading ratio R corresponding to the sheet size will be described later.

[0052] At this time, the marker loading ratio R is set to an amount that definitely exceeds 50%. The larger the marker loading ratio R, the greater the margin for preventing the markers 34 from falling due to vibrations and wind pressure, but the effect of reducing the amount of marker consumption becomes smaller.

[0053] A marker length fine adjustment function for more secure marker loading will be described in conjunction with Figure 14. Figure 14 is a flowchart including an operation flow including a normal mode and a marker back exposure function that is not in the normal mode. In the above embodiment, if the marker length calculated by the above formula (1) is too short, the behavior of the marker during and after landing may become unstable due to influences such as variations in landing position caused by wind pressure and air resistance of the internal airflow. Therefore, the value of the marker loading ratio R is made variable, and is set so that the value of the marker loading ratio R increases as the sheet width length increases. In the example of this embodiment, the value of the marker loading ratio R is set to 55% to 75% (see step S3 in the flowchart of FIG. 14).

[0054] As an example of an embodiment, the marker transport end timing (or marker transport time) may be prepared in advance in multiple patterns, and a setting value to be applied for each sheet width length range may be assigned (in other words, the setting value to be applied may be extracted from a so-called data table and assigned). In other words, instead of calculating the marker transport time tm every time printing is performed as described above, the marker transport time tm for each sheet size can be stored in advance in the image forming apparatus 1 or the marking device 33A. By implementing it in this way, it becomes possible to arbitrarily set the marker transport time tm regardless of the calculation formula.

[0055] Next, we will explain the function of exposing the back of the marker to the opposite side of the stacked sheet bundle. When the sheets are thin and the markers are inserted many times, the stacked sheet bundle will have localized thickness deviations due to the markers. This can lead to, for example, false detection of the top surface of the sheets, which can lead to transport and stacking errors.

[0056] On the other hand, if the marker transport time tm is increased, it is possible to extend the marker 34 to the opposite side of the marking device 33A as seen from the sheet stack (hereinafter referred to as back exposure). By using such a back exposure function, the visibility of the separation position is improved and thickness deviation in the width direction of the stacked sheet stack can be reduced.

[0057] Specifically, when the marker back exposure function mode is set to ON, the marker can be transported from the side where the marking device 33A is provided to the sheet edge on the opposite side of the sheet center by calculating the marker transport time tm using the following formula (2): At this time, the marker can be loaded with the marker 34 protruding from the sheet edge on the opposite side by the length set by α in the following calculation formula (2). The user setting items of the image forming apparatus 1 include, for example, an ON / OFF setting item for the marker back exposure function mode on the operation unit 10 in Figure 1, and when the back exposure function is on, the marker transport time tm is calculated using the following equation (2). In the above formula (2), the meanings of the symbols used are as follows. tm: Marker conveyance time Wp: Sheet width length x: Distance from the center of sheet conveyance to the cutter of the marking device vm: Marker conveyance speed α: Marker exposure length (arbitrary value)

[0058] In the above formula (2), as the marker exposure length α, about 20 to 30 mm is used.

[0059] The operation flow of FIG. 14 will be described. As shown in FIG. 14, when a sheet conveyance start command of the image forming apparatus 1 is issued, it is determined whether the on-key of the marker back exposure function mode is pressed by the user at the operation unit 10 of FIG. 1 and the marker back exposure function mode is set to ON (executable) (steps S1 to step S2). In step S2, if the answer is NO and the marker back exposure function mode is not executable, the process proceeds to step S3, and the range of the sheet width length Wp of the sheet S to be conveyed is determined in three steps. Specifically, when the sheet width length Wp < a, the marker loading ratio R is 55%, when a ≤ sheet width length Wp < b, the marker loading ratio R is 60%, and when b ≤ sheet width length Wp < a, the marker loading ratio R is 75%.

[0060] Next, the process proceeds to step S4, and the marker conveyance time tm is determined by the above formula (1) using the sheet width length Wp and the marker loading ratio R as arguments. Next, when sheet conveyance starts in step S5 and marker insertion starts in step S6, the process ends.

[0061] On the other hand, if the marker back exposure function mode is set to ON and the mode is executable (YES) in step S2, the process proceeds to step S7, where the marker transport time tm is determined by the above formula (2) using the sheet width Wp as an argument. Next, the sheet transport starts in step S5, and the marker insertion starts in step S6, and the process ends.

[0062] 15(a) and 15(b), the effects obtained by the marking device 33A of the embodiment described above will be further described. As shown in FIG. 15(a), the marking device 33A changes the length of the marker 34 inserted to separate the stack of sheets in accordance with the sheet width Wp of the sheet size to be loaded on the stacking tray 14, thereby enabling the center of gravity g of the marker 34 to be reliably placed on the stack of sheets. This makes it possible to prevent the marker 34 from falling off when small sizes are loaded. 15(b), the amount of markers consumed can be reduced for large-sized sheets. Overall, the marking device 33A can prevent markers from falling when the sheet width is small, and can reduce the amount of markers consumed when the sheet width is large.

[0063] In the above embodiment, an example was shown in which an inkjet recording device that forms full-color images was used as an image forming device to which the present invention can be applied, but the image forming device to which the present invention can be applied is not limited to this, and the present invention can also be applied to copying machines, facsimiles, multifunction machines, etc. In addition, in the above embodiment, a configuration is shown in which a sheet is used as a recording medium on which an image is formed, but this sheet S is not limited to recording paper, but also includes cardboard, postcards, roll paper, envelopes, plain paper, thin paper, coated paper (coated paper, art paper, etc.), tracing paper, OHP sheets, OHP film, resin film, etc. Any material that is in sheet form, can be used as long as it is capable of forming an image and has hygroscopic properties.

[0064] The above embodiments and the like can be said to have essentially described the following aspects and effects. That is, the first aspect is a marking device that transports sheets stacked on a stacking table to sequentially place markers on the topmost sheet so that the sheet stack spacing is an arbitrary sheet stack spacing in a sheet width length perpendicular to the sheet transport length of the sheet stack stacked on the stacking table, and has a sheet size information storage means that stores sheet transport length information and sheet width length information, and the marking device acquires the sheet width length information from the sheet size information storage means and delays the timing of the marker transport end according to the acquired sheet width length information. With this configuration, according to the first aspect, it is possible to provide a marking device that can optimize the marker length in accordance with the sheet width length of the sheet size.

[0065] A second aspect is the first aspect, characterized in that the marker conveyance end timing is delayed as the sheet width length information is longer and is advanced as the sheet width length information is shorter. With this configuration, according to the second aspect, sheets with a small sheet width length will not fall off the top sheet stacked on the stacking table, and marker consumption can be reduced for sheets with a large sheet width length.

[0066] The third aspect is a marking device in the second aspect, characterized in that the timing of the marker transport end is calculated by a function with the sheet width length as a variable, and the marker center of gravity is always controlled to be positioned above the stack of sheets stacked on the top surface of the stacking table. With this configuration, according to the third aspect, when the marker lands, the marker rests on the stacked sheet.

[0067] The fourth aspect is characterized in that, in the third aspect, the derivation formula for the marker transport end timing has a marker loading ratio as a variable, the marker loading ratio is calculated to be larger as the sheet width length is larger, and the marker transport end timing is calculated to be larger as the marker loading ratio is larger. With this configuration, according to the fourth aspect, even if the marker is too short, the marker can be reliably placed on the stacking sheet without falling due to disturbances such as wind pressure before it lands.

[0068] The fifth aspect is characterized in that, in the second aspect, the marker transport end timing is divided into multiple groups according to the range of the sheet width length, a value is pre-set for each group, and is automatically applied according to the sheet width length. With this configuration, according to the fifth aspect, it is possible to set an arbitrary marker length in accordance with the sheet width without using a derivation formula.

[0069] The sixth aspect is characterized in that the first aspect is provided with an on / off setting item for the marker back exposure function and a setting item for the marker back exposure amount, and when the marker back exposure function is on, the marker conveyance end timing is calculated according to the sheet width length information and the set marker back exposure amount. With this configuration, according to the sixth aspect, it is possible to expose the marker on the side opposite to the marking device by the amount required depending on the width of the sheet.

[0070] A seventh aspect is an image forming apparatus comprising the marking device according to any one of the first to sixth aspects. With this configuration, according to the seventh aspect, it is possible to provide a marking device or an image forming device that can optimize the marker length in accordance with the sheet width length in the sheet size.

[0071] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to such specific embodiments, and unless otherwise specifically limited in the above description, various modifications and changes are possible within the scope of the spirit of the present invention as described in the claims. The effects described in the embodiments of the present invention are merely examples of the most preferable effects resulting from the present invention, and the effects of the present invention are not limited to those described in the embodiments of the present invention. [Explanation of symbols]

[0072] 1. Image forming device 2-sheet feeder 4 Imaging device 10 Control section 11 Sheet size detection sensor 14 Loading platform 17 Trigger Sensor 33A Marking Device 34 Marker 35a Outlet 39 Motor 40 cutters 41 Transport Timer 42 Cut Timer 43 Marker transport timer 44 Marker Cut Timer 62 Condition acquisition section 63 Marker transport time determination unit 64 Control Unit 65 Storage section g Marker center of gravity R Marker Loading Ratio S seat Wp Sheet width and length [Prior art documents] [Patent documents]

[0073] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-098826

Claims

1. 1. A marking device that conveys sheets stacked on a stacking table so as to sequentially place markers on the uppermost sheet of the sheet stack stacked on the stacking table at an arbitrary interval between the sheet stacks in a sheet width length perpendicular to the sheet conveying length of the sheet stack, a sheet size information storage means for storing sheet conveyance length information and sheet width length information; The marking device acquires the sheet width length information from the sheet size information storage means, and delays a marker conveyance end timing in accordance with the acquired sheet width length information.

2. 2. The marking device according to claim 1, The marking device is characterized in that the marker conveyance end timing is delayed as the sheet width length information is longer and is advanced as the sheet width length information is shorter.

3. 3. The marking device according to claim 2, A marking device characterized in that the timing of ending the marker transport is calculated by a function with the sheet width length as a variable, and the marker center of gravity is always controlled to be positioned above the stack of sheets stacked on the top surface of the stacking table.

4. 4. The marking device according to claim 3, A marking device characterized in that the derivation formula for the marker transport end timing has a marker loading ratio as a variable, the marker loading ratio is calculated to be larger as the sheet width length is larger, and the marker transport end timing is calculated to be larger as the marker loading ratio is larger.

5. 3. The marking device according to claim 2, A marking device characterized in that the marker transport end timing is divided into multiple groups according to the range of the sheet width length, a value is pre-set for each group, and the value is automatically applied according to the sheet width length.

6. 2. The marking device according to claim 1, It has an on / off setting for the marker back exposure function and a setting for the amount of marker back exposure. When the marker back exposure function is on, the marker transport end timing is calculated in accordance with the sheet width length information and the set marker back exposure amount.

7. An image forming apparatus comprising the marking device according to any one of claims 1 to 6.

Images