Destaticizing device and image forming system including destaticizing device

Abstract

To enable a user to measure the charge amount of the sheet with no need of preparation of a grounding environment for grounding the conductive plate and the potential measuring device.SOLUTION: There is provided a destaticizing device that eliminates static electricity from a sheet on which an image is formed by an image forming apparatus. The destaticizing device comprises: a destaticizing unit that eliminates static electricity from a sheet on which an image is formed by an image forming apparatus; a receiving unit that receives a setting of a static elimination level of the destaticizing unit; and a grounded terminal that is provided on a top surface or a front surface of the destaticizing device.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a static eliminator that eliminates static electricity from a sheet and an image forming system including the static eliminator. [Background technology]

[0002] When an image is formed on a sheet by an image forming apparatus, the sheet may become charged. If sheets that have been charged when an image is formed on them by the image forming apparatus are stacked in a post-processing device or a stacker device, the discharged sheets may stick together due to the electrostatic force between them. Therefore, Patent Document 1 describes a static elimination device that eliminates static electricity from a sheet using a static elimination roller that comes into contact with the paper to eliminate static electricity and a non-contact static eliminator that eliminates static electricity without coming into contact with the sheet. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-167169 Summary of the Invention [Problem to be solved by the invention]

[0004] Because the charge characteristics of a sheet vary depending on the type of sheet, it is preferable to set the voltage value applied to the static elimination unit appropriately depending on the type of sheet. Furthermore, even for the same type of sheet, the charge characteristics of the sheet vary depending on the printing environment, etc. Therefore, in order to perform appropriate static elimination, it is desirable for the user to measure the charge amount of the sheet and then set the static elimination voltage value. To accurately measure the charge amount of the sheet, it is necessary to ground the conductive plate on which the sheet is placed and the potential meter that measures the charge amount of the sheet. Conventionally, the user has had to prepare the grounding environment for these conductive plates and potential meter, which has led to the problem of reduced user work efficiency.

[0005] Therefore, the present invention aims to provide an electrostatic elimination device and an image forming system equipped with the electrostatic elimination device that simplifies the preparation of a grounding environment when a user measures the charge amount of a sheet, thereby improving the user's work efficiency. [Means for solving the problem]

[0006] One aspect of the present invention is a static elimination device that eliminates static electricity from a sheet on which an image has been formed by an image forming apparatus, characterized in that the static elimination device comprises: a static elimination unit that eliminates static electricity from a sheet on which an image has been formed by the image forming apparatus; a reception unit that receives the setting of the static elimination level of the static elimination unit; and a grounded terminal provided on the top or front surface of the static elimination device. [Effects of the Invention]

[0007] According to the present invention, the user does not need to prepare a grounding environment for grounding a conductive plate or a potential measuring device in order to measure the amount of charge on a sheet, thereby improving work efficiency. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic cross-sectional view of an image forming system. [Figure 2] FIG. 4 is a schematic diagram showing a connecting member that connects devices together. [Figure 3] FIG. [Figure 4] FIG. [Figure 5] Schematic diagram of a cooling unit. [Figure 6] FIG. 2 is a schematic diagram of a static elimination unit. [Figure 7] FIG. 1 is a perspective view of an image forming system. [Figure 8] FIG. [Figure 9] Schematic diagram of the static eliminator seen from the left side. [Figure 10] FIG. 2 is a block diagram illustrating communication in the image forming system. [Figure 11] 10 is a graph showing the static elimination characteristics of a sheet. [Figure 12]10 is a graph showing variations in sheet static elimination characteristics. [Figure 13] 10 is a flowchart illustrating a process for adjusting a static elimination setting value. [Figure 14] FIG. 2 is a perspective view showing the configuration when measuring the amount of charge on a sheet according to the first embodiment. [Figure 15] FIG. 4 is an enlarged top view showing a connector portion of the configuration when measuring the amount of charge on a sheet according to the first embodiment. [Figure 16] FIG. 10 is a perspective view showing a first modified example of the first embodiment. [Figure 17] FIG. 10 is a perspective view showing a second modification of the first embodiment. [Figure 18] FIG. 10 is a perspective view showing the configuration of a second embodiment. [Figure 19] FIG. 10 is a perspective view showing a modified example of the second embodiment. [Figure 20] FIG. 10 is a perspective view showing the configuration of a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Example 1] The following describes embodiments of the present invention with reference to the drawings. Note that the dimensions, materials, shapes, relative positions, etc. of the components described below are not intended to limit the scope of the present invention unless otherwise specified.

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The XYZ coordinate system shown in the drawings is used to explain the installation direction of the image forming system. More specifically, the X axis indicates the left-right direction (width direction) of the image forming system, and the direction indicated by the X-axis arrow in the XYZ coordinate system is the right direction of the installed image forming system, and the direction opposite to the direction indicated by the X-axis arrow in the XYZ coordinate system is the left direction of the installed image forming system. In the following description, "right" in the drawings means the direction indicated by the X-axis arrow, and "left" in the drawings means the opposite direction to the direction indicated by the X-axis arrow. Furthermore, the Y axis indicates the front-rear direction (depth direction) of the image forming system, and the direction indicated by the Y-axis arrow in the XYZ coordinate system is the rear direction of the installed image forming system, and the direction opposite to the direction indicated by the Y-axis arrow in the XYZ coordinate system is the front direction of the installed image forming system. In the following description, "rear" in the drawings means the direction indicated by the Y-axis arrow, and "front" in the drawings means the opposite direction to the direction indicated by the Y-axis arrow. The Z axis indicates the height direction of the image forming system, with the direction indicated by the Z axis arrow in the XYZ coordinate system being the upward direction of the installed image forming system, and the opposite direction of the Z axis arrow in the XYZ coordinate system being the downward direction of the installed image forming system. In the following description, "upward" in the drawing means the direction indicated by the Z axis arrow, and "downward" in the drawing means the opposite direction of the Z axis arrow. In the drawing, the circle symbols indicate the tips of the arrows on the X, Y, and Z axes, and the cross symbols within the circle symbols indicate the tails of the arrows on the X, Y, and Z axes.

[0011] <Configuration of image forming system> The schematic configuration of the image forming system in this embodiment will be described using Figures 1, 2, and 3. Figure 1 is a schematic cross-sectional view of the image forming system in this embodiment. Figure 2 is a schematic view showing connecting members that connect each device. Figure 3 is an enlarged view showing a delivery section for a sheet S.

[0012] The image forming system 1000 includes an image forming apparatus 100 that forms an image on a sheet S, a cooling device 200 that cools the sheet S on which the image has been formed by the image forming apparatus 100, a static eliminator 300 that eliminates charge on the surface of the sheet, and a discharged sheet stacker 400 that stacks the discharged sheets S. The cooling device 200 and the static eliminator 300 are configured to be connectable to the image forming apparatus 100 as peripheral devices (referred to as optional units, etc.) that can be added later to expand the functions of the image forming apparatus 100.

[0013] The image forming apparatus 100, cooling apparatus 200, static eliminator 300, and discharged paper stacker 400 are each formed in a separate housing, and the housing frame serves as the frame ground. The respective housing frames are electrically connected and grounded by conductors 180. In this embodiment, the conductors 180 are flat-braided copper wires. The apparatuses are connected using a connection configuration as shown in FIG. 2. An attachment / detachment unit 51 is provided in the apparatus upstream in the conveyance direction of the sheet S, while an attachment / detachment claw unit 52 is provided in the apparatus downstream. For example, the attachment / detachment unit 51 is provided in the image forming apparatus 100, and the attachment / detachment claw unit 52 is provided in the cooling apparatus 200, which is opposite the attachment / detachment unit 51. The connection between the cooling apparatus 200 and static eliminator 300 and the connection between the static eliminator 300 and discharged paper stacker 400 are also configured similarly. The attachment / detachment unit 51 has an attachment / detachment shaft 51a extending toward the attachment / detachment claw unit 52. On the other hand, the detachable claw 52 is formed with an engaging portion 52a that engages with the detachable shaft 51a when connected. The detachable claw 52 is provided so as to be able to swing freely relative to the device housing, and by swinging in the direction of arrow A shown in Figure 2 and engaging with the detachable shaft 51a, the devices are fixed and arranged so that they do not move relative to each other.

[0014] The transfer configuration of the sheet S between the apparatuses will be described using the connection portion between the image forming apparatus 100 and the cooling apparatus 200 as an example. As shown in FIG. 3, the image forming apparatus 100 is provided with a pair of discharge guides 41, and the cooling apparatus 200 is provided with a pair of receiving guides 42. The pair of discharge guides 41 are arranged above and below each other with a gap therebetween so that they face each other. The pair of receiving guides 42 are also arranged above and below each other with a gap therebetween so that they face each other. The sheet S discharged from the discharge port 100A is guided by the discharge guides 41 and delivered to the cooling apparatus 200 via the receiving opening 42a. The opening between the pair of receiving guides 42 and furthest upstream in the conveyance direction of the sheet S is the receiving opening 42a for the sheet S of the cooling apparatus 200. In this embodiment, the discharge guide 41 has a guide portion 41a extending toward the cooling apparatus 200. The discharge guide 41 has the guide portion 41a, so that the sheet S is discharged by the discharge rollers 15 from the discharge port 100A to the cooling device 200.

[0015] On the other hand, the receiving guide 42 is formed so that it widens on the image forming apparatus 100 side to match the shape of the guide portion 41a of the discharge guide 41 so that the discharge guide 41 can enter. Also, the receiving guide 42 has a conveyance path for the sheet S that continues to the delivery roller 16. According to the above configuration, the image forming apparatus 100 and the cooling device 200 are connected so that the sheet S can be delivered from the image forming apparatus 100 to the cooling device 200 without getting caught. The sheet delivery configuration between the cooling device 200 and the static eliminator 300 and the sheet delivery configuration between the static eliminator 300 and the discharged paper stacker 400 are also configured similarly.

[0016] <Configuration of image forming device> The image forming apparatus 100 shown in Fig. 1 is a tandem-type electrophotographic full-color printer. The image forming apparatus 100 has image forming units PY, PM, PC, and PK that form yellow, magenta, cyan, and black images, respectively. The image forming apparatus 100 forms a toner image on a sheet S in response to an image signal from a document reading device 110 connected to the apparatus main body 100B or an external device such as a personal computer connected to the apparatus main body 100B so as to be able to communicate with the apparatus main body 100B. The sheet S may be made of various types of sheet material, such as plain paper, cardboard, rough paper, textured paper, coated paper, plastic film, cloth, etc.

[0017] As shown in FIG. 1, the image forming units PY, PM, PC, and PK are arranged in the apparatus main body 100B (inside the apparatus main body) along the movement direction of the intermediate transfer belt 8. The intermediate transfer belt 8 is stretched around multiple rollers and configured to travel in the direction of arrow R2. The intermediate transfer belt 8 carries and transports the toner image transferred in the primary transfer. A secondary transfer roller 9 and an opposing roller 10 are arranged to sandwich the intermediate transfer belt 8. The toner image formed on the intermediate transfer belt 8 is transferred to the sheet S at the secondary transfer unit T2. A transfer voltage of the same polarity as the normal charge polarity of the toner is applied to the secondary transfer roller 9. In this embodiment, since the toner has a negative polarity, a negative voltage is applied to the secondary transfer roller 9. Meanwhile, the opposing roller 10 is electrically grounded. However, a voltage of the opposite polarity to the normal charge polarity of the toner may be applied to the opposing roller 10 to electrically ground the secondary transfer roller 9. A fixing device 11 is arranged downstream of the secondary transfer unit T2 in the sheet transport direction.

[0018] In this embodiment, a plurality of cassettes 12 containing sheets S are arranged in the lower portion of the image forming apparatus 100. Each cassette 12 contains sheets S of different sizes and thicknesses, and a sheet S is selectively transported from one of the plurality of cassettes 12. The sheet S is transported from the cassette 12 toward the registration roller 14 by the transport roller 13. Thereafter, the registration roller 14 starts to rotate in synchronization with the toner image formed on the intermediate transfer belt 8, and the sheet S is transported to the secondary transfer portion T2. ​​Note that the sheet S is not limited to the sheet S contained in the cassette 12, and a sheet S placed on a manual feed portion (not shown) may also be transported.

[0019] The four image forming units PY, PM, PC, and PK included in the image forming apparatus 100 have substantially the same configuration except for the different developing colors. Therefore, the image forming unit PK will be described here as a representative, and descriptions of the other image forming units will be omitted.

[0020] Figure 4 is a schematic diagram showing the image forming unit. As shown in Figure 4, the image forming unit PK is provided with a cylindrical photosensitive drum 1 as a photosensitive member. The photosensitive drum 1 is driven to rotate in the direction of arrow R1. Around the photosensitive drum 1, a charging device 2, an exposure device 3, a developing device 4, a primary transfer roller 5, and a cleaning device 6 are arranged.

[0021] The process of forming, for example, a full-color image using the image forming apparatus 100 will be described. First, when the image forming operation starts, the surface of the rotating photosensitive drum 1 is uniformly charged by the charging device 2. The charging device 2 is, for example, a corona charger that irradiates charged particles associated with corona discharge to charge the photosensitive drum 1 to a uniform negative dark potential. Next, the photosensitive drum 1 is scanned and exposed by laser light L corresponding to an image signal emitted from the exposure device 3. As a result, an electrostatic latent image corresponding to the image signal is formed on the surface of the photosensitive drum 1. The electrostatic latent image formed on the photosensitive drum 1 is visualized by toner (developer) contained in the developing device 4, becoming a visible image.

[0022] The toner image formed on the photosensitive drum 1 is primarily transferred onto the intermediate transfer belt 8 at a primary transfer section T1 formed between the photosensitive drum 1 and a primary transfer roller 5 disposed across the intermediate transfer belt 8. At this time, a primary transfer bias is applied to the primary transfer roller 5. Any toner remaining on the surface of the photosensitive drum 1 after the primary transfer is removed by a cleaning device 6.

[0023] Returning to FIG. 1, the above-described operation is performed sequentially at each of the yellow, magenta, cyan, and black image forming units PY to PK, and the four color toner images are superimposed on the intermediate transfer belt 8. Thereafter, in synchronization with the formation of the toner images, the sheet S stored in the cassette 12 is conveyed to the secondary transfer unit T2. Then, by applying a secondary transfer bias to the secondary transfer roller 9, the full-color toner images formed on the intermediate transfer belt 8 are secondarily transferred onto the sheet S all at once.

[0024] Next, the sheet is attracted to the conveying device 70, for example by air suction, and conveyed to the fixing device 11. The fixing device 11 has a fixing roller 11A as a heating unit arranged to rotate freely, and a pressure roller 11B as a pressure unit that rotates while being pressed against the fixing roller 11A and can sandwich and convey the sheet S together with the fixing roller 11A. The fixing roller 11A is rotated at a predetermined rotation speed (for example, 400 mm / sec) by a drive motor (not shown) while being pressed against the pressure roller 11B. A halogen heater 11C as a heat source is arranged within the fixing roller 11A, and the fixing device 11 can heat the sheet S by raising the surface temperature of the fixing roller 11A by the halogen heater 11C.

[0025] The fixing device 11 pinches and conveys the sheet S on which the toner image has been formed in a fixing nip T3 formed by the fixing roller 11A and the pressure roller 11B, and heats and pressurizes the conveyed sheet S to fix the toner image to the sheet S. That is, the toner of the toner image formed on the sheet S is melted and mixed by the heat and pressure, and is fixed to the sheet S as a full-color image. In this way, a series of image formation processes is completed.

[0026] In this embodiment, the image forming apparatus 100 is capable of double-sided printing. In the case of single-sided printing, the sheet S, on which the image has been fixed by the fixing device 11, is discharged from the image forming apparatus main body through the discharge port 100A (see FIG. 3) by the discharge rollers 15. In the case of double-sided printing, the sheet S, on which the image has been fixed by the fixing device 11, is conveyed to the double-sided inverting conveyance path 60. In the double-sided inverting conveyance path 60, the sheet S is inverted so that the front and back sides of the sheet S are swapped. The inverted sheet S is conveyed toward the registration rollers 14, and is conveyed to the secondary transfer unit T2 by the registration rollers 14 with the unprinted back side facing the intermediate transfer belt 8. In the secondary transfer unit T2, the full-color toner image formed on the intermediate transfer belt 8 is secondarily transferred all at once to the sheet S (back side). Thereafter, the toner image on the sheet S is fixed by the fixing device 11, and the fixed sheet S is discharged through the discharge port 100A (see FIG. 3).

[0027] <Optional unit configuration> The cooling device 200 includes a cooling unit 201, a cooling control unit 220, an entrance roller pair 214, and an exit roller pair 215. The sheet S discharged from the image forming apparatus 100 is delivered to the cooling device 200 and passes through the cooling unit 201. The cooling unit 201 has a function of lowering the temperature of the sheet heated by the fixing device 11 to a predetermined temperature or lower. The cooled sheet S is delivered from the cooling device 200 to the static eliminator 300 by the exit roller pair 215.

[0028] The static elimination device 300 includes a static elimination unit 301, a static elimination control unit 320, a static elimination input unit 330, a pair of entrance rollers 314, and a pair of exit rollers 315. In this embodiment, a negative voltage is applied to the secondary transfer roller 9. This negative voltage causes the upper surface of the sheet to be negatively charged, and the lower surface of the sheet to be positively charged due to dielectric polarization. If sheets are stacked on the discharge tray 401 without being neutralized, there is a risk that the stacked sheets will stick together due to electrostatic force. In this embodiment, to prevent sheets from sticking together due to electrostatic force, the static elimination unit 301 in the static elimination device 300 removes charge from the sheet surface. The static elimination unit 301 in this embodiment has two configurations: one that eliminates static charge by contacting the sheet S, and one that eliminates static charge without contact. The neutralized sheet S is delivered to the discharge stacking device 400 by the pair of exit rollers 315.

[0029] In the discharge stacking device 400, sheets S are stacked on a discharge tray 401 serving as a stacking unit. The discharge stacking device 400 includes a pair of entrance rollers 414, a pair of exit rollers 415, a stacking detection unit 402, and the discharge tray 401. The discharge tray 401 is provided so as to be movable in the vertical direction (the Z direction in FIG. 1). Therefore, by lowering the discharge tray 401 relative to the pair of exit rollers 415, the sheets S can be stacked up to a predetermined height. The stacking device 400 is provided with a stacking detection unit 402 for detecting that the stacked sheets S have reached the predetermined height. The stacking detection unit 402 may detect the position of the discharge tray 401, or may detect the stacking height of the sheets S stacked on the discharge tray 401.

[0030] <Cooling unit configuration> The configuration of the cooling unit 201 will be described using FIG. 5. FIG. 5 is a schematic diagram of the cooling unit 201. The cooling unit 201 is supported on a housing of the cooling device 200. The cooling unit 201 has an endless first belt 21 (conveyor belt, first conveyor belt) wound around a plurality of tension rollers 22a to 22d, and an endless second belt 25 (conveyor unit, second conveyor belt) that sandwiches and conveys the sheet S with the first belt 21. In this embodiment, the first belt 21 is provided on the fixing roller 11A side of the fixing device 11, and the second belt 25 is provided on the pressure roller 11B side. The cooling unit 201 has a heat sink 30 that cools at least one of the first belt 21 and the second belt 25. In this embodiment, the first belt 21 and the second belt 25 constitute a conveyor unit that conveys the sheet S.

[0031] At least one of the tension rollers 22a to 22d of the first belt 21 is rotated by a drive unit (not shown). As a result, the first belt 21 moves in a circular motion in the direction of arrow B in the figure. On the other hand, the second belt 25 is looped around a plurality of second belt tension rollers 26a to 26d and is in contact with the first belt 21. Therefore, the second belt 25 moves in a circular motion following the first belt 21. Note that, in this example, the first belt 21 is driven to cause the second belt 25 to follow the first belt 21, but the second belt 25 may be driven to cause the first belt 21 to follow the second belt 25. Alternatively, both the first belt 21 and the second belt 25 may be driven.

[0032] The sheet S on which the toner image has been fixed is sandwiched between the first belt 21 and the second belt 25, and is transported in the transport direction (the direction of arrow C in the figure) as these belts rotate. At that time, the sheet S passes through a cooling nip T4, which is a nip portion formed by the contact between the first belt 21 and the second belt 25. In the case of this embodiment, the first belt 21 is cooled by the heat sink 30, which is brought into contact with the inner circumferential surface of the first belt 21 in the cooling nip T4. This is because the contact between the heat sink 30 and the first belt 21 conducts heat from the first belt 21 to the heat sink 30 and is dissipated by the heat sink 30.

[0033] The heat sink 30 is a heat dissipation plate made of metal such as aluminum. The heat sink 30 has a heat receiving portion 30a as a contact surface that contacts the inner circumferential surface of the first belt 21 to remove heat from the first belt 21, a heat dissipation portion 30b that dissipates heat, and a fin base 30c that conducts heat from the heat receiving portion 30a to the heat dissipation portion 30b. In addition, a cooling fan 40 is provided that blows air toward the heat sink 30 (more specifically, the heat dissipation portion 30b) to forcibly cool (dissipate heat) the heat sink 30 itself.

[0034] <Configuration of static eliminator> Next, the configuration of the static eliminator 300 will be described with reference to Figures 6, 7, 8, and 9. Figure 6 is a schematic diagram of the static eliminator unit 301. Figure 7 is a perspective view of the image forming system. Figure 8 is an enlarged view of the top of the static eliminator. Figure 9 is a schematic diagram of the static eliminator as viewed from the left side.

[0035] (Configuration of static elimination unit) The static eliminator 300 is provided with a static eliminator unit 301. As shown in Fig. 6, in this embodiment, the static eliminator unit 301 is made up of a contact static eliminator 340 that comes into contact with the sheet S to eliminate static electricity, and non-contact static eliminators 351 and 352 that eliminate static electricity without coming into contact with the sheet S.

[0036] The contact static elimination unit 340 is composed of static elimination rollers 341 and 342 as a pair of static elimination rollers, and eliminates static electricity from the sheet S while in contact with the sheet at the nip between the two static elimination rollers 341 and 342. The static elimination roller 342 is electrically grounded. The static elimination roller 341, which faces the static elimination roller 342, is connected to a static elimination high-voltage power supply 343, and a static elimination bias Vd is applied from the static elimination high-voltage power supply 343. Specifically, the static elimination control unit 320 applies a negative voltage to the static elimination roller 341 to eliminate positive charges present on the lower surface of the sheet S. Then, as the positive charges present on the lower surface of the sheet S decrease, the negative charges present on the upper surface of the sheet S also decrease. In this embodiment, the contact static elimination unit 340 directly contacts the sheet S to eliminate static electricity, thereby providing a high static elimination effect. However, the contact static elimination unit 340 tends to have large variations in the surface potential of the sheet S after static elimination processing, making static elimination uneven. However, the arrangement of the static elimination high-voltage power supply 343 is not limited to this. The static elimination roller 341 may be electrically grounded, and the static elimination high-voltage power supply 343 may apply a positive voltage to the static elimination roller 342, thereby eliminating the negative charge present on the upper surface of the sheet S. Furthermore, two static elimination power supplies may be connected to the static elimination rollers 341 and 342, respectively.

[0037] Non-contact static eliminators 351 and 352 are provided downstream of the contact static eliminator 340 in the conveyance direction. In this embodiment, the non-contact static eliminators 351 and 352 are ionizers. The ionizers have static eliminator needles and generate positive and negative ions. The generated ions neutralize the charge on the surface of the charged sheet S, thereby eliminating static electricity from the sheet S. The non-contact static eliminators 351 and 352 have a lower static elimination effect than the contact static eliminator 340, but they reduce the variation in the surface potential of the sheet S after static elimination processing. Therefore, the non-contact static eliminators 351 and 352 can even out the surface potential of the sheet S that has become uneven due to the contact static eliminator 340. Note that, although ionizers are used for the non-contact static eliminators 351 and 352 in this embodiment, this is not a limitation. The non-contact static eliminators may be configured using a discharge wire or a ground electrode. In this embodiment, the non-contact static eliminators 351 and 352 are disposed on both the upper and lower sides of the conveyance path (not shown), but this is not limiting. For example, a discharge wire or an ionizer may be disposed only on the upper side of the sheet.

[0038] In this example, the static elimination unit 301 employs both a contact type and a non-contact type in which the static elimination member is brought into contact with the sheet, but this is not limitative. For example, a configuration employing only one of the types may be used.

[0039] (Configuration of the top of the static eliminator) The top surface 300A and front surface 300B of the static eliminator 300 form the exterior of the static eliminator 300. The front of the top surface 300A has a recess, and the recess is provided with a static elimination input unit 330 and a ground connector 360, which will be described later. The front surface 300B is made up of a door 382 and an upper front surface 381 (see FIG. 9). The door 382 is configured to be openable and closable by an opening and closing mechanism (not shown). The upper front surface 381 has an inclined portion 381A. The front surface is located on the front side (opposite the direction indicated by the arrow on the Y axis), and the user frequently works in front of the device.

[0040] As shown in FIGS. 7 and 8 , a static elimination input unit 330 is provided at the top and front of the static elimination device 300. The static elimination input unit 330 is fixedly connected to the static elimination device 300 by a support member 362. The static elimination input unit 330 is, for example, various input keys, dials, or a touch panel. The user inputs the setting value of the static elimination bias Vd into the static elimination input unit 330. The static elimination input unit 330 sends a signal corresponding to the user's operation to the reception unit 322 of the static elimination control unit 320. The static elimination voltage value may be received not only through the static elimination input unit 330 but also via, for example, the operation unit 130 or an external computer. The external computer may be a smartphone or tablet carried by the user. The static elimination input unit 330 has a static elimination display unit 331. The static elimination display unit 331 displays, for example, the setting value of the static elimination bias Vd and the ON / OFF switching status of the non-contact static eliminators 351 and 352. As will be described later, it is also possible to display that the mode is the adjustment mode when the user sets the static elimination bias adjustment mode using the static elimination input unit 330. In this embodiment, the static elimination input unit 330 is installed on the top surface 300A of the static elimination device 300, but it may also be installed on the front surface 300B of the static elimination device 300. However, the input method and display method are not limited to the static elimination voltage value itself, and the level of static elimination amount (static elimination level) may also be displayed as a numerical value in 10 stages, for example.

[0041] A ground connector 360 is provided on the support member 362. The frame 302, which is the housing frame, is the frame ground and is electrically grounded. As shown in FIG. 9, the ground connector 360 is in contact with the frame 302 of the static eliminator 300 and is electrically grounded. The ground connector 360 has a bottom surface 360A and a side surface 360B. The bottom surface 360A is provided with a screw hole 360A1, which is threadedly fitted with a fixing screw 361 (see FIG. 15). In this embodiment, the fixing screw 361 is also provided so that a terminal of an object that needs to be grounded can be securely connected to the ground connector 360. The side surface 360B is connected to the bottom surface 360A and is disposed approximately perpendicular to the bottom surface 360A. The side surface 360B has a substantially circular hole 360B1, which can be gripped by a clip terminal. In this embodiment, the ground connector 360 is a terminal having a structure for fixing or holding the terminal of a ground wire connected to an object (for example, the electric potential measuring device 510 or the conductive plate 500 shown in FIG. 14). However, the ground connector 360 is not limited to fixing or holding the terminal of the ground wire of the object, and may also have a structure around which the copper wire of the ground wire can be wound.

[0042] By providing the ground connector 360 at the upper front, when there is an object that needs to be grounded or in a grounded state (for example, the electric potential measuring device 510 or the conductive plate 500), the user can easily ground or ground the object. The ground connector 360 is preferably disposed near the static elimination input unit 330. In this embodiment, the ground connector 360 and the static elimination input unit 330 are disposed in a recess disposed at the front of the top surface 300A. In other words, the ground connector 360 and the static elimination input unit 330 are disposed on the same surface.

[0043] <Communication Configuration of Image Forming System Equipped with Static Eliminator> The communication configuration of an image forming system equipped with the static eliminator 300 of this embodiment will be described with reference to Fig. 10. However, in addition to those shown in the figure, various devices such as operating motors and power supplies are connected to the image forming system, but illustration and description of these devices will be omitted here as they are not the main focus of the invention.

[0044] FIG. 10 is a block diagram showing communication in the image forming system. The image forming apparatus 100 includes a control unit 120. The cooling device 200 includes a cooling control unit 220. The static elimination device 300 includes a static elimination control unit 320. The discharged paper stacking device 400 includes a discharged paper stacking control unit 420. The control unit 120 controls various aspects of the image forming apparatus 100, such as image formation operations, and includes a CPU (Central Processing Unit) and memory 121, such as ROM, RAM, or a hard disk drive. The memory 121 stores various programs, such as image formation jobs, and various data, such as list data of sheet characteristics. The control unit 120 can execute various programs stored in the memory 121 in response to jobs input from the operation unit 130 or an external PC (not shown), and can execute the various programs to operate the image forming apparatus 100. The control unit 120 is communicatively connected to the cooling control unit 220, the static elimination control unit 320, and the discharged paper stacking control unit 420, and can operate the cooling unit 201, the stacking unit 403, etc. via each control unit.

[0045] As mentioned above, the control unit 120 of the image forming device 100 is connected to each control unit for communication, so it is also possible to display the status of the image forming device 100 and the status of each device on the display unit 131 of the image forming device 100 via communication between each control unit.

[0046] In addition, when an operation setting is made in the discharge input unit 330 of the discharge device 300, communication is made from the discharge control unit 320 to the control unit 120 of the image forming device 100, and the image forming device 100 can operate according to the setting.

[0047] Note that list data of static elimination characteristics (the relationship between static elimination bias and the amount of charge on the sheet after static elimination) according to the type of sheet is stored in the memory 121 or static elimination memory 321 in the image forming apparatus, and is configured to be communicated as appropriate between the control unit 120 and static elimination control unit 320. Therefore, for example, when the type of sheet to be printed is designated on the operation unit 130, the static elimination control unit 320 can obtain a reference value for the static elimination bias Vd setting value from the memory 121 or static elimination memory 321. The obtained reference value for the static elimination bias Vd setting value can be displayed on the static elimination display unit 331 of the static elimination input unit 330.

[0048] The reception unit 322 receives instructions from the user via the static elimination input unit 330. Since the control unit 120 of the image forming apparatus 100 and the static elimination control unit 320 are connected for communication, the reception unit 322 may receive instructions from the user via the operation unit 130 of the image forming apparatus 100.

[0049] <Explanation of the process for adjusting the static elimination bias of the static eliminator> The flow for adjusting the static elimination bias setting value of the static elimination device 300 in this embodiment will be described using the figures. First, factors for adjusting the static elimination bias setting value will be described using Figs. 11 and 12. Fig. 11 is a graph showing static elimination characteristics for each sheet type. The horizontal axis is the static elimination bias Vd setting value input to the static elimination high-voltage power supply 343 (see Fig. 6) of the static elimination device 300, and the vertical axis is the potential of the sheet surface measured by a potential meter after static elimination processing. The sheet surface is the surface onto which an image is transferred at the secondary transfer section T2 of the image forming apparatus 100.

[0050] As shown in Figure 11, the static elimination characteristics (the relationship between the static elimination bias and the amount of charge on the sheet after static elimination) differ depending on the type of sheet. As shown in Figure 11, in order to make the potential of the sheet after static elimination approximately 0 V, a static elimination bias with a larger absolute value must be set for Media A than for Media B and Media C. In other words, the appropriate static elimination bias for keeping the amount of charge on the sheet after static elimination within an acceptable range differs depending on the type of sheet. In recent years, there has been a demand for printing on a variety of sheets. For example, there is an increasing demand for image formation on sheets with high electrical resistance, such as transparent film, synthetic paper (film-based synthetic paper made primarily of polypropylene), and specialty paper (e.g., recording material made primarily of limestone). The static elimination characteristics of these sheets also vary.

[0051] Figure 12 is a graph showing the static elimination characteristics of a certain high-resistivity sheet A. The values ​​on the horizontal and vertical axes are the same as those in the graph in Figure 11. Arrow E indicates the range of variation in the static elimination characteristics of sheet A, and as shown in Figure 12, static elimination characteristics vary even for the same type of sheet. One factor causing this variation is that the condition of the sheet or static elimination device changes due to changes in the printing environment, such as humidity and temperature.

[0052] The range F shown in FIG. 12 is the sheet charge amount that does not cause problems when the sheet is ejected and stacked. Even if a target static elimination bias setting value for sheet A is input, the sheet charge amount after static elimination will vary within the range indicated by the arrow Vp depending on the printing environment, etc. In this case, there is a possibility that the sheet charge amount will exceed the allowable range of charge amount F. In other words, even if static elimination characteristic data for the sheet on which an image is formed is stored in the memory 121 or static elimination memory 321, there is a risk that the desired sheet charge amount (range F in FIG. 12) will not be achieved even after static elimination by the static elimination device 300 due to variations in the static elimination characteristics of the sheet. Therefore, in this embodiment, in order to keep the sheet charge amount within the desired range, the user adjusts the static elimination bias setting value of the static elimination device before starting printing.

[0053] Next, the configuration and adjustment flow when adjusting the static elimination bias setting value Vd of the static elimination device 300 in this embodiment will be described with reference to Figures 13, 14, and 15. First, before describing the flow for adjusting the static elimination bias setting value, the configuration when measuring the charge amount of a sheet in this embodiment will be described with reference to Figures 14 and 15. Figure 14 is a perspective view showing the configuration when measuring the charge amount of a sheet, which is set as part of the adjustment flow, and Figure 15 is an enlarged top view showing the connector portion of the configuration when measuring the charge amount of a sheet.

[0054] To stably measure the charge amount of a sheet discharged onto the discharge tray 401, a grounded conductive plate 500 on which the sheet is placed and a grounded potential meter 510 are required. When measuring the charge amount of a sheet, a user grounds the conductive plate 500 and the potential meter 510 using the ground connector 360 of the static eliminator 300. Specifically, the conductive plate 500 is electrically connected to a cable 501, and a terminal 501A of the cable 501 is connected to the ground connector 360 (connection portion) by a fixing screw 361. At this time, the terminal 501A of the cable 501 is clamped between the fixing screw 361 and a screw hole 360A1. Similarly, the potential meter 510 is electrically connected to a cable 511, and is connected to the ground connector 360 (connection portion) by a clip terminal 511A of the cable 511. At this time, the clip terminal 511A of the cable 511 is clamped into a hole 360B1 of the ground connector 360. That is, ground connector 360 can be connected to a terminal, and the user attaches terminal 501A or clip terminal 511A to ground connector 360. This eliminates the need for the user to prepare a separate grounding environment for grounding conductive plate 500 or potential meter 510. However, depending on the type of potential meter, grounding of the potential meter is not necessarily required. The conductive plate is, for example, a stainless steel or aluminum plate made of a material with an electrical resistance of approximately 100 μΩ·cm or less.

[0055] Next, an adjustment flow for determining the static elimination bias setting value Vd will be described with reference to FIG. 13. In this embodiment, it is possible to execute a normal mode in which static elimination of the sheet S is performed as part of a print job, and a static elimination adjustment mode in which the user adjusts the static elimination bias setting value of the static elimination device. The static elimination adjustment mode is executed when an appropriate static elimination bias setting value for the sheet to be used in the print job is unknown. In the static elimination adjustment mode, a test print is executed. In the test print, a preset test toner image (test pattern image) is formed on the sheet. Then, static elimination processing is executed on the sheet on which the test toner image has been formed, using the static elimination bias value set by the user, and the sheet is output to the paper output tray 401.

[0056] The user can select the mode to be executed in the static elimination input unit 330. The reception unit 322 receives the setting of the mode selected by the user via the static elimination input unit 330. When the static elimination adjustment mode is selected by the user, the static elimination bias set value is adjusted according to the adjustment flow described below. Figure 13 is a flowchart showing the adjustment flow for determining the static elimination bias set value Vd of the static elimination high-voltage power supply 343 (see Figure 6).

[0057] First, the adjustment flow starts when the static elimination input unit 330 of the static elimination device 300 accepts the selection of the static elimination adjustment mode by the user. The static elimination adjustment mode starts, and the static elimination control unit 320 acquires a target static elimination bias setting value that corresponds to the type of sheet that has already been set from the memory 121 or static elimination memory 321 (step S1).

[0058] Next, a target static elimination bias setting value is determined by the static elimination control unit 320 and displayed on the static elimination display unit 331. If the target value for the target sheet is not registered in the memory, the user may set it using the static elimination input unit 330 (step S2).

[0059] Once the discharge bias setting value is set, a signal is transmitted from the discharge control unit 320 to the control unit 120, and the image forming apparatus 100 executes a test print, and one sheet discharged at the set discharge bias setting value is output to the output tray 401 (step S3).

[0060] The amount of charge on the sheet output onto the paper output tray 401 is measured by the user. As described above, the amount of charge on the sheet is measured by placing the sheet to be measured on the grounded conductive plate 500 without turning it over from the ejected state, and measuring it with the potential measuring device 510 (step S4). Next, the user checks whether the value of the potential measuring device 510 is equal to or less than ±F [V], which is the desired charge amount. In this embodiment, the desired charge amount is set to about ±200V (step S5).

[0061] If the measurement result is within the desired range of the charge amount, the end of the charge removal adjustment is set in the charge removal input unit 330, and the adjustment flow is ended.

[0062] If the measurement result is outside the desired charge amount range, the user adjusts the charge removal bias setting value again. In this embodiment, as shown in Figure 6, the charge removal high-voltage power supply 343 applies a negative voltage to the charge removal roller 341. Therefore, if the sheet is not sufficiently neutralized, the upper surface of the sheet measured by the potential meter will be negatively charged. In contrast, if the voltage applied to the charge removal roller is excessive, the polarity of the sheet after neutralization will be reversed, and the upper surface of the sheet measured by the potential meter will be positively charged. Therefore, if the sheet charge amount deviates toward the negative potential, the charge removal bias setting value is adjusted toward the negative side (increasing the absolute value) from the target charge removal bias setting value. If the sheet charge amount deviates toward the positive potential, the charge removal bias setting value is adjusted toward the positive side (decreasing the absolute value) from the target charge removal bias setting value (step S6). Then, based on the adjustment direction, the user re-enters the charge removal bias setting value, performs a test print, and repeats the sheet charge amount measurement until the sheet charge amount is within the desired range. If the measurement result is within the desired charge amount range, the charge removal adjustment is terminated in the charge removal input unit 330, and the adjustment flow ends.

[0063] When the end of the static elimination adjustment is set in the static elimination input unit 330, a signal is sent from the static elimination control unit 320 to the control unit 120, and the image forming apparatus 100 starts a print job.

[0064] However, step S1 may be omitted. Furthermore, the user may adjust the static elimination bias setting value Vd in normal mode, not just adjustment mode. In normal mode, static elimination processing is performed using the static elimination bias setting value set via the static elimination input unit 330. Therefore, by inputting the static elimination bias setting value into the static elimination input unit 330 and printing any one sheet, the same adjustment flow as in adjustment mode can be performed.

[0065] A modification of the first embodiment will now be described. In this embodiment, a support member 362 supporting the static elimination input unit 330 may be connected to the frame 302 and electrically grounded. Furthermore, as shown in FIG. 16, a ground connector 360 may be configured on the top surface of the static elimination device 300 at a position different from the static elimination input unit 330. The position of the ground connector 360 is preferably within reach of the user. In this embodiment, the length L of the static elimination device 300 in the front-rear direction is 700 mm, and the ground connector 360 is preferably disposed on the top surface within a range of 460 mm from the front, which is approximately two-thirds of the length L.

[0066] 17, the ground connector 360 may be configured on the front surface of the static elimination device 300 at a position different from that of the static elimination input unit 330. In other words, it is sufficient that the ground connector 360 and the static elimination input unit 330 are located at the front upper portion of the static elimination device 300. In other words, it is sufficient that the ground connector 360 and the static elimination input unit 330 are each located either within a range of 460 mm from the front of the top surface 300A or at the front upper portion 381 of the front surface 300B.

[0067] By locating the ground connector 360 near the static elimination input unit 330, the ground connector 360 is within reach even when the user stands in front of the static elimination input unit 330. This simplifies the adjustment flow, as there is no need to move when measuring the amount of charge on the sheet and inputting the static elimination bias setting value in the static elimination bias adjustment process. In addition, the user can input the static elimination setting value into the static elimination input unit 330 while checking the measurement results of the potential meter 510.

[0068] In addition, in the present embodiment, the devices adjacent to the static eliminator 300 are the cooling device 200 and the discharged paper stacking device 400, but this is not limiting. For example, a device that corrects the curl amount of a sheet, an inspection device that detects defects in a printed image, or the like may be adjacent to the static eliminator 300 on the upstream and downstream sides in the sheet conveyance direction.

[0069] [Example 2] In this embodiment, another form of static eliminator will be described with reference to FIG. 18. Embodiment 2 of the present invention is applied to the same image forming system as described in Embodiment 1, and description of components other than the static eliminator will be omitted. In Embodiment 1, the static eliminator 300 has a ground connector 360 for grounding the conductive plate 500 on which the sheet is placed, and the user connects the conductive plate 500 to the ground connector 360 in order to ground the conductive plate 500. In Embodiment 2, the static eliminator 300 is provided with an electrically grounded sheet placement surface 370, and the user places a sheet on the electrically grounded sheet placement surface 370.

[0070] FIG. 18 is a perspective view showing the configuration of the second embodiment. The static eliminator 300 is provided with a static elimination input unit 330 and a ground connector 360 at the upper front portion. The static eliminator 300 also has an electrically grounded sheet placement surface 370 on its top surface. The sheet placement surface 370 is rectangular and larger than the sheet placed on the sheet placement surface 370. The sheet placement surface 370 is connected to the frame 302 shown in FIG. 9. In the second embodiment, the static eliminator 300 has an electrically grounded sheet placement surface 370, eliminating the need for the user to prepare a conductive plate 500. The sheet placement surface is electrically conductive and is made of a material such as stainless steel or aluminum with an electrical resistance of approximately 100 μΩ·cm or less. It is preferable that the sheet placement surface be flat and smooth. The ground connector 360 is preferably located closer to the user than the sheet placement surface 370.

[0071] The sheet placement surface 370 is used as a surface on which a test-printed sheet is placed in the flow for adjusting the static elimination bias setting value described in the first embodiment. In addition, the cable of the potential measuring device 510 can be connected to the ground connector 360 to establish a grounded state. This eliminates the need for the user to prepare the conductive plate 500. Furthermore, the user does not need to prepare a grounded environment for grounding the potential measuring device 510.

[0072] By arranging the ground connector 360 and the sheet placement surface 370 near the static elimination input unit 330, the ground connector 360 and the sheet placement surface 370 are within reach even when the user stands in front of the static elimination input unit 330. This makes it possible to simplify the adjustment flow of the static elimination bias setting value. Furthermore, the user can input the static elimination setting value into the static elimination input unit 330 while checking the measurement results of the potential meter 510.

[0073] A modified example of the second embodiment described above is shown in Fig. 19. An electrically grounded sheet placement surface 370 is provided on the top surface of the static eliminator 300. The sheet placement surface 370 also serves as the exterior of the static eliminator 300, and may be, for example, a colored steel plate of the same color as the other exterior colors.

[0074] [Example 3] In this embodiment, the configuration of an image forming system equipped with a static eliminator will be described with reference to Fig. 20. Embodiment 3 of the present invention is applied to the same image forming system as described in Embodiment 1, and description of parts other than the grounded sheet placement surface in this embodiment will be omitted. In Embodiment 2, the electrically grounded sheet placement surface 370 was disposed on the top surface 300A of the static eliminator 300. In Embodiment 3, the sheet placement surface 370 is disposed on the top surface of a unit adjacent to the static eliminator 300.

[0075] 20 is a perspective view showing the configuration of embodiment 3. A static elimination input unit 330 and a ground connector 360 are provided at the front upper portion of the static eliminator 300. A cooling device 200 is connected adjacent to the static eliminator 300 upstream in the sheet conveyance direction of the static eliminator 300. Furthermore, a discharged paper stacking device 400 is connected adjacent to the static eliminator 300 downstream in the sheet conveyance direction of the static eliminator 300.

[0076] An electrically grounded sheet placement surface 270 is provided on the top surface 200A of the cooling device 200. The sheet placement surface 270 is rectangular and larger than the sheet placed on the sheet placement surface 270. The sheet placement surface is electrically conductive and is made of a material such as stainless steel or aluminum, with an electrical resistance of approximately 100 μΩ·cm or less. It is preferable that the sheet placement surface is flat and without any irregularities. It is preferable that the ground connector 360 is located in an area to the right of the center of the static eliminator 300. In other words, arranging the ground connector 360 near the sheet placement surface 270 of the cooling device 200 improves user operability.

[0077] The sheet placement surface 270 is used as a surface on which a test-printed sheet is placed in the flow for adjusting the static elimination bias setting value described in the first embodiment. In addition, it is possible to connect the cable of the potential measuring device 510 using the ground connector 360 to establish a grounded state. This eliminates the need for the user to prepare the conductive plate 500. Furthermore, it is also unnecessary for the user to prepare a grounded environment for grounding the potential measuring device 510.

[0078] By arranging the ground connector 360 and the sheet placement surface 270 near the static elimination input unit 330, the ground connector 360 and the sheet placement surface 270 are within reach even when the user stands in front of the static elimination input unit 330. This makes it possible to simplify the adjustment flow of the static elimination bias setting value. Furthermore, the user can input the static elimination setting value into the static elimination input unit 330 while checking the measurement results of the potential meter 510.

[0079] As a modification of the third embodiment described above, an electrically grounded sheet placing surface may be provided on the top surface 400A of the discharged paper stacking device 400 adjacent to and downstream in the conveyance direction of the static eliminator 300. In this case, it is preferable that the ground connector 360 is disposed in an area to the left of the center of the static eliminator.

[0080] In addition, in this embodiment, the devices adjacent to the static eliminator 300 are the cooling device 200 and the discharged paper stacking device 400, but this is not limiting. For example, a device that corrects the curl amount of a sheet, an inspection device that detects defects in a printed image, or the like may be adjacent to the static eliminator 300 on the upstream and downstream sides in the sheet conveyance direction. [Explanation of symbols]

[0081] 100 Image forming device 180 Conductor 200 Cooling device 300 Static eliminator 301 Static Elimination Unit 302 frames 320 Static elimination control unit 330 Static elimination input section 360 Ground Connector 361 Fixing screw 362 Support member 370 Sheet placement surface 400 Paper ejection stacking device 401 Paper output tray 500 Conductive Plate 510 Potential Meter

Claims

1. A static eliminator that eliminates static electricity from a sheet on which an image is formed by an image forming apparatus, a static elimination unit that eliminates static electricity from a sheet on which an image is formed by an image forming apparatus; a reception unit for receiving a setting of a static elimination level of the static eliminator; a grounded terminal provided on a top or front surface of the static eliminator; Equipped with A static eliminator characterized by:

2. the static eliminator includes an input unit into which a user's instruction is input, the input unit is disposed on the top surface or the front surface of the static eliminator; 2. The static eliminator according to claim 1.

3. the terminal is disposed on the top surface of the static eliminator, and is disposed within a range of two-thirds of the length of the static eliminator from the front in the depth direction.

3. The static eliminator according to claim 2.

4. the charge removal unit includes a first charge removal roller and a second charge removal roller, and removes charge from the sheet while being in contact with the sheet at a nip portion formed by the first charge removal roller and the second charge removal roller; 2. The static eliminator according to claim 1.

5. The terminal includes a bottom surface portion having a screw hole that can be connected to a fixing screw.

2. The static eliminator according to claim 1.

6. The terminal is disposed substantially perpendicular to the bottom surface portion and includes a side surface portion provided with a hole that can be connected to the terminal.

6. The static eliminator according to claim 5.

7. the top surface includes a grounded conductive plate; 2. The static eliminator according to claim 1.

8. the static eliminator includes an input unit into which a user's instruction is input, the input portion and the terminal are disposed forward of the conductive plate; 8. The static eliminator according to claim 7.

9. The terminal is used to ground a conductive plate on which the sheet is placed when measuring the amount of charge on the sheet or a potential measuring device that measures the amount of charge on the sheet.

2. The static eliminator according to claim 1.

10. The static eliminator according to any one of claims 1 to 9, The image forming apparatus, An image forming system comprising:

Images