Static elimination device and image forming system equipped with the static elimination 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 for eliminating static electricity from a sheet and an image forming system including the same.

Background Art

[0002] When an image is formed on a sheet by an image forming apparatus, the sheet may be charged. When charged sheets are stacked in a post-processing apparatus or a stacker apparatus after the image is formed by the image forming apparatus, the sheets may stick to each other due to the electrostatic force between the discharged sheets. Therefore, Patent Document 1 describes a static eliminator that eliminates static electricity from a sheet using a static elimination roller that contacts the paper to eliminate static electricity and a non-contact type static eliminator that eliminates static electricity in a non-contact state with the sheet.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Since the charging characteristics of the sheet vary depending on the type of the sheet, it is preferable that the voltage value applied to the static elimination unit be appropriately set according to the type of the sheet. Further, even in the case of the same type of sheet, the charging characteristics of the sheet vary depending on the printing environment and the like. Therefore, in order to perform suitable static elimination, it is desirable that the user measures the charge amount of the sheet and then sets the static elimination voltage value. In order to accurately measure the charge amount of the sheet, it is necessary to ground a conductive plate on which the sheet is placed and a potential measuring device that measures the charge amount of the sheet. Conventionally, the user has prepared a grounding environment for grounding these conductive plates and potential measuring devices, and there has been a problem that the working efficiency of the user is reduced.

[0005] Therefore, the present invention aims to provide a static elimination device and an image forming system equipped with a static elimination device that simplify the preparation of the grounding environment when a user measures the amount of charge on 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 for eliminating static electricity from a sheet image-formed by an image-forming apparatus, comprising: a static elimination unit for eliminating static electricity from a sheet image-formed by an image-forming apparatus; a receiving unit for receiving 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 conductive plates or potential measuring instruments in order to measure the charge level of the sheet, thereby improving work efficiency. [Brief explanation of the drawing]

[0008] [Figure 1] A schematic cross-sectional view of an image forming system. [Figure 2] A schematic diagram showing connecting members that link devices together. [Figure 3] An enlarged view showing a close-up of the sheet transfer area. [Figure 4] A schematic diagram showing the image forming section. [Figure 5] Schematic diagram of the cooling unit. [Figure 6] A schematic diagram of the static elimination unit. [Figure 7] Perspective view of an image forming system. [Figure 8] Enlarged view of the top of the static elimination device. [Figure 9] A schematic diagram of a static eliminator viewed from the left side. [Figure 10] A block diagram illustrating the communication of an image forming system. [Figure 11] A graph showing the static electricity removal characteristics of the sheet. [Figure 12]Graph showing the variation in sheet static elimination characteristics. [Figure 13] Flowchart explaining the process of adjusting the static elimination setting value. [Figure 14] Perspective view showing the configuration during sheet charge measurement in Embodiment 1. [Figure 15] Upper enlarged view showing the connector part of the configuration during sheet charge measurement in Embodiment 1. [Figure 16] Perspective view showing Modified Example 1 of Embodiment 1. [Figure 17] Perspective view showing Modified Example 2 of Embodiment 1. [Figure 18] Perspective view showing the configuration of Embodiment 2. [Figure 19] Perspective view showing a modified example of Embodiment 2. [Figure 20] Perspective view showing the configuration of Embodiment 3.

Modes for Carrying Out the Invention

[0009] [Example 1] Hereinafter, the modes for carrying out the present invention will be described with reference to the drawings. Note that the dimensions, materials, shapes, relative arrangements, etc. of the component parts described below are not intended to limit the scope of this invention only to those, unless specifically stated.

[0010] Hereinafter, in the embodiments according to the present invention, an explanation will be given while referring to the drawings. Note that the XYZ coordinate system shown in the drawings is shown for explaining 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, the direction indicated by the arrow of the X-axis in the XYZ coordinate system is the right direction of the installed image forming system, and the opposite direction of the direction indicated by the arrow of the X-axis in the XYZ coordinate system is the left direction of the installed image forming system. In the following description, the right side in the drawing means the direction indicated by the arrow of the X-axis, and the left side in the drawing means the opposite direction of the direction indicated by the arrow of the X-axis. Also, the Y-axis indicates the front-back direction (depth direction) of the image forming system, the direction indicated by the arrow of the Y-axis in the XYZ coordinate system is the depth direction of the installed image forming system, and the opposite direction of the direction indicated by the arrow of the Y-axis in the XYZ coordinate system is the front direction of the installed image forming system. In the following description, the rear side in the drawing means the direction indicated by the arrow of the Y-axis, and the front side in the drawing means the opposite direction of the direction indicated by the arrow of the Y-axis. Further, the Z-axis indicates the height direction of the image forming system, the direction indicated by the arrow of the Z-axis in the XYZ coordinate system is the upward direction of the installed image forming system, and the opposite direction of the direction indicated by the arrow of the Z-axis in the XYZ coordinate system is the downward direction of the installed image forming system. In the following description, the upper side in the drawing means the direction indicated by the arrow of the Z-axis, and the lower side in the drawing means the opposite direction of the direction indicated by the arrow of the Z-axis. And, the ○ symbol in the drawing indicates the tip of the arrow of each of the X, Y, and Z axes, and the × symbol inside the ○ symbol indicates the rear end of the arrow of each of 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 with reference to FIGS. 1, 2, and 3. FIG. 1 is a schematic cross-sectional view of the image forming system in this embodiment. FIG. 2 is a schematic view showing the connecting members that connect the respective devices. FIG. 3 is an enlarged view showing an enlarged delivery portion of the sheet S.

[0012] The image forming system 1000 includes an image forming apparatus 100 for forming an image on a sheet S, a cooling device 200 for cooling the sheet S on which the image has been formed by the image forming apparatus 100, a static elimination device 300 for removing static charge from the sheet surface, and a paper discharge and stacking device 400 for stacking the discharged sheets S. The cooling device 200 and the static elimination device 300 are configured to be connectable to the image forming apparatus 100 as peripheral devices (sometimes called optional units) that can be added later to extend the functionality of the image forming apparatus 100.

[0013] The image forming apparatus 100, the cooling apparatus 200, the static eliminator 300, and the paper discharge and stacking apparatus 400 are each formed in separate housings, and the housing frames are frame grounds. Each housing frame is electrically connected and grounded by a conductor 180. In this embodiment, a flat braided copper wire is used for the conductor 180. The devices are connected by a connection configuration as shown in Figure 2. A detachable part 51 is provided on the device upstream in the conveying direction of the sheet S, while a detachable claw part 52 is provided on the device downstream. For example, the image forming apparatus 100 is provided with a detachable part 51, and the cooling apparatus 200, which is opposite it, is provided with a detachable claw part 52. The connection between the cooling apparatus 200 and the static eliminator 300, and the connection between the static eliminator 300 and the paper discharge and stacking apparatus 400 have a similar configuration. The detachable part 51 has a detachable shaft 51a that extends toward the detachable claw part 52. On the other hand, the detachable claw portion 52 has an engaging portion 52a that engages with the detachable shaft 51a when connected. The detachable claw portion 52 is pivotably mounted on the device housing and pivots in the direction of arrow A shown in Figure 2 to engage with the detachable shaft 51a, thereby fixing the devices in place so that they do not move relative to each other.

[0014] The configuration for transferring sheets S between devices will be explained using the connection between the image forming apparatus 100 and the cooling device 200 as an example. As shown in Figure 3, the image forming apparatus 100 is provided with a pair of discharge guides 41, and the cooling device 200 is provided with a pair of receiving guides 42. The pair of discharge guides 41 are arranged vertically with a gap between them so that they face each other. Similarly, the pair of receiving guides 42 are arranged vertically with a gap between them so that they face each other. The sheets S discharged from the discharge port 100A are guided by these discharge guides 41 and transferred to the cooling device 200 via the receiving port 42a. Here, the opening furthest upstream in the direction of sheet S transport between the pair of receiving guides 42 is the receiving port 42a for the sheets S of the cooling device 200. In this embodiment, the discharge guide 41 has a guide portion 41a that extends toward the cooling device 200 side. Because the discharge guide 41 has a guide portion 41a, the sheet S is discharged from the discharge port 100A to the cooling device 200 by the paper discharge roller 15.

[0015] On the other hand, the receiving guide 42 is formed so that the image forming apparatus 100 side widens to match the shape of the guide portion 41a of the discharge guide 41, allowing the discharge guide 41 to enter. The receiving guide 42 also has a transport path for the sheet S that leads to the transfer roller 16. With the above configuration, the image forming apparatus 100 and the cooling device 200 are connected so that the sheet S can be transferred from the image forming apparatus 100 to the cooling device 200 without getting caught. The sheet transfer configuration between the cooling device 200 and the static eliminator 300, and the sheet transfer configuration between the static eliminator 300 and the paper discharge stacking device 400 are similar.

[0016] <Configuration of an image forming apparatus> The image forming apparatus 100 shown in Figure 1 is an electrophotographic tandem full-color printer. The image forming apparatus 100 has image forming units PY, PM, PC, and PK, which 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 an original document reader 110 connected to the main body 100B, or from an external device such as a personal computer that is communicatively connected to the main body 100B. Various types of sheet materials can be used for the sheet S, such as plain paper, cardboard, rough paper, textured paper, coated paper, plastic film, and cloth.

[0017] As shown in Figure 1, the image forming units PY, PM, PC, and PK are arranged in a line along the direction of movement of the intermediate transfer belt 8 within the main body 100B of the device. The intermediate transfer belt 8 is stretched over multiple rollers and is configured to travel in the direction of arrow R2. The intermediate transfer belt 8 carries and transports the toner image that has been transferred in the primary transfer. The secondary transfer roller 9 and the opposing roller 10 are arranged so as to sandwich the intermediate transfer belt 8. The toner image formed on the intermediate transfer belt 8 is transferred to the sheet S in the secondary transfer unit T2. The secondary transfer roller 9 is subjected to a transfer voltage with the same polarity as the normal charge polarity of the toner. In this embodiment, since the toner has a negative polarity, a negative voltage is applied to the secondary transfer roller 9. On the other hand, the opposing roller 10 is electrically grounded. However, the opposing roller 10 may be subjected to a voltage with the opposite polarity to the normal charge polarity of the toner, thereby electrically grounding the secondary transfer roller 9. A fixing device 11 is located downstream of the secondary transfer unit T2 in the sheet transport direction.

[0018] In this embodiment, multiple cassettes 12 containing sheets S are arranged at the bottom of the image forming apparatus 100. Each cassette 12 contains sheets S of different sizes and thicknesses, and sheets S are selectively transported from any of the multiple cassettes 12. The sheets S are transported from the cassettes 12 toward the registration rollers 14 by transport rollers 13. Then, the registration rollers 14 start rotating in synchronization with the toner image formed on the intermediate transfer belt 8, and the sheets S are transported to the secondary transfer section T2. ​​Note that the transport is not limited to sheets S contained in the cassettes 12; sheets S placed on a manual feed section (not shown) may also be transported.

[0019] The four image forming units PY, PM, PC, and PK of the image forming apparatus 100 have substantially the same configuration except for the difference in development color. Therefore, the image forming unit PK will be described as a representative unit, and the 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, a cylindrical photosensitive drum 1 is installed as a photoreceptor in the image forming unit PK. The photosensitive drum 1 is rotated in the direction of arrow R1. A charging device 2, an exposure device 3, a developing device 4, a primary transfer roller 5, and a cleaning device 6 are arranged around the photosensitive drum 1.

[0021] The process of forming, for example, a full-color image using the image forming apparatus 100 will now be described. First, when the image forming operation is started, 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 charges the photosensitive drum 1 to a uniform negative polarity dark potential by irradiating it with charged particles associated with corona discharge. Next, the photosensitive drum 1 is scanned and exposed by laser light L corresponding to the 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 made visible by toner (developer) contained in the developing device 4, becoming a visible image.

[0022] The toner image formed on the photosensitive drum 1 is transferred to the intermediate transfer belt 8 in the primary transfer section T1, which consists of the drum 1 and the primary transfer roller 5 positioned on either side of the intermediate transfer belt 8. At this time, a primary transfer bias is applied to the primary transfer roller 5. After the primary transfer, any toner remaining on the surface of the photosensitive drum 1 is removed by the cleaning device 6.

[0023] Returning to Figure 1, the above operations are performed sequentially in the yellow, magenta, cyan, and black image forming units PY to PK, and the four toner images are superimposed on the intermediate transfer belt 8. Then, in accordance with the toner image formation timing, the sheet S housed in the cassette 12 is transported to the secondary transfer unit T2. By applying a secondary transfer bias to the secondary transfer roller 9, the full-color toner image formed on the intermediate transfer belt 8 is transferred to the sheet S all at once.

[0024] Next, the sheet is transported to the fixing device 11, for example, by air suction on the conveying device 70. The fixing device 11 has a fixing roller 11A as a heating unit that is rotatably arranged, and a pressure roller 11B as a pressing unit that rotates while being pressed against the fixing roller 11A and can grip and transport the sheet S together with the fixing roller 11A. The fixing roller 11A is rotated at a predetermined rotational 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 heating source is arranged inside the fixing roller 11A, and the fixing device 11 can heat the sheet S by raising the surface temperature of the fixing roller 11A with the halogen heater 11C.

[0025] The fixing device 11 holds and transports the sheet S on which the toner image has been formed at the fixing nip T3 formed by the fixing roller 11A and the pressure roller 11B. The transported sheet S is then heated and pressurized to fix the toner image to the sheet S. That is, the toner in the toner image formed on the sheet S is melted and mixed by the heating and pressurizing, fixing it to the sheet S as a full-color image. In this way, the 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 fixed by the fuser 11 is discharged from the discharge port 100A (see Figure 3) to the outside of the image forming apparatus by the paper discharge roller 15. In the case of double-sided printing, the sheet S fixed by the fuser 11 is transported to the double-sided inversion transport path 60. In the double-sided inversion transport path 60, the sheet S is inverted, and the front and back sides of the sheet S are swapped. The inverted sheet S is transported toward the registration roller 14, and the registration roller 14 transports the sheet S to the secondary transfer section T2 with the unprinted back side facing the intermediate transfer belt 8. In the secondary transfer section T2, the full-color toner image formed on the intermediate transfer belt 8 is transferred to the back side of the sheet S all at once. After that, the toner image on the sheet S is fixed by the fuser 11, and the fixed sheet S is discharged from the discharge port 100A (see Figure 3).

[0027] <Configuration of optional units> The cooling device 200 comprises a cooling unit 201, a cooling control unit 220, an inlet roller pair 214, and an outlet roller pair 215. The sheet S discharged from the image forming apparatus 100 is passed to the cooling device 200 and passes through the cooling unit 201. The cooling unit 201 has the function of lowering the temperature of the sheet heated by the fixing device 11 to below a predetermined temperature. The cooled sheet S is then passed from the cooling device 200 to the static eliminator 300 by the outlet 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, an inlet roller pair 314, and an outlet roller pair 315. In this embodiment, a negative voltage is applied to the secondary transfer roller 9. As a result, the upper surface of the sheet becomes negatively charged, and the lower surface of the sheet becomes positively charged due to dielectric polarization. If the sheets are loaded onto the paper output tray 401 without being statically eliminated, there is a risk that the loaded sheets will stick together due to electrostatic force. In this embodiment, to prevent the sheets from sticking together due to electrostatic force, the static elimination unit 301 in the static elimination device 300 removes the charge from the sheet surface. In this embodiment, the static elimination unit 301 has two configurations: one that eliminates static charge by contacting the sheet S, and one that eliminates static charge without contact. The statically eliminated sheets S are then transferred to the paper output stacking device 400 by the outlet roller pair 315.

[0029] In the paper output and stacking device 400, the sheets S are loaded onto the paper output tray 401, which serves as the stacking section. The paper output and stacking device 400 comprises an inlet roller pair 414, an outlet roller pair 415, a stacking detection unit 402, and a paper output tray 401. The paper output tray 401 is provided to be movable in the vertical direction (Z direction in Figure 1). Therefore, by lowering the paper output tray 401 relative to the outlet roller pair 415, the sheets S can be stacked to a predetermined height. The stacking device 400 is provided with a stacking detection unit 402 for detecting when the stacked sheets S have reached a predetermined height. The stacking detection unit 402 may detect the position of the paper output tray 401, or it may detect the stacking height of the sheets S loaded onto the paper output tray 401.

[0030] <Cooling unit configuration> The configuration of the cooling unit 201 will be explained using Figure 5. Figure 5 is a schematic diagram of the cooling unit 201. The cooling unit 201 is supported by the housing of the cooling device 200. The cooling unit 201 has an endless first belt 21 (conveyor belt, first conveyor belt) wrapped around a plurality of tension rollers 22a to 22d, and an endless second belt 25 (conveyor section, second conveyor belt) that sandwiches and conveys the sheet S between 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. Also in this embodiment, the first belt 21 and the second belt 25 constitute a conveyor unit that conveys the sheet S.

[0031] The first belt 21 is rotated by a drive unit (not shown) on at least one of the tension rollers 22a to 22d. 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 wrapped around multiple 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. Here, the first belt 21 is driven to cause the second belt 25 to follow the first belt 21, but the opposite may be done, where the second belt 25 is 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 held between the first belt 21 and the second belt 25 and transported in the transport direction (direction of arrow C in the figure) as these belts move circumferentially. 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 this embodiment, the first belt 21 is cooled by the heat sink 30 by contacting the inner circumferential surface of the first belt 21 in the cooling nip T4. This is because, when the heat sink 30 contacts the first belt 21, the heat from the first belt 21 is conducted to the heat sink 30 and dissipated by the heat sink 30.

[0033] The heat sink 30 described above is a heat dissipation plate made of a metal such as aluminum. The heat sink 30 has a heat receiving section 30a as a contact surface for contacting the inner circumferential surface of the first belt 21 to remove heat from the first belt 21, a heat dissipation section 30b for dissipating heat, and a fin base 30c for conducting heat from the heat receiving section 30a to the heat dissipation section 30b. In addition, a cooling fan 40 is provided to forcibly cool (dissipate heat from) the heat sink 30 itself by blowing air toward the heat sink 30 (more specifically, the heat dissipation section 30b).

[0034] <Configuration of a static eliminator> Next, the configuration of the static elimination device 300 will be explained using Figures 6, 7, 8, and 9. Figure 6 is a schematic diagram of the static elimination 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 elimination device. Figure 9 is a schematic diagram of the static elimination device viewed from the left side.

[0035] (Configuration of the static elimination unit) The static elimination device 300 is provided with a static elimination unit 301. As shown in Figure 6, in this embodiment, the static elimination unit 301 consists of a contact static elimination section 340 that performs static elimination by contacting the sheet S, and non-contact static elimination sections 351 and 352 that perform static elimination without contacting 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 the sheet S is statically eliminated while in contact with the sheet at the nip portions of the two static elimination rollers 341 and 342. Static elimination roller 342 is electrically grounded. Static elimination roller 341, which is opposite to 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 the positive charge present on the lower surface of the sheet S. As the positive charge present on the lower surface of the sheet S decreases, the negative charge present on the upper surface of the sheet S also decreases. In this embodiment, the contact static elimination unit 340 has a high static elimination effect because it eliminates static electricity by directly contacting the sheet S. On the other hand, the contact static elimination unit 340 tends to have a large variation in the surface potential of the sheet S after static elimination treatment, 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 to eliminate negative charges present on the upper surface of the sheet S. Alternatively, two static elimination power supplies may be connected to the static elimination rollers 341 and 342, respectively.

[0037] Non-contact static elimination units 351 and 352 are provided downstream of the contact static elimination unit 340 in the transport direction. In this embodiment, the non-contact static elimination units 351 and 352 are ionizers. The ionizer has a static elimination needle and generates 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 elimination units 351 and 352 have a lower static elimination effect compared to the contact static elimination unit 340, but the variation in the surface potential of the sheet S after static elimination is smaller. Therefore, the non-contact static elimination units 351 and 352 can equalize the surface potential of the sheet S that has become uneven due to the contact static elimination unit 340. In this embodiment, ionizers are used for the non-contact static elimination units 351 and 352, but this is not the only option. The non-contact static elimination units may be composed of discharge wires or earth electrodes. In this embodiment, the non-contact static elimination units 351 and 352 are arranged on both the upper and lower sides of a transport path (not shown), but this is not the only configuration. For example, a configuration in which the discharge wire and ionizer are arranged only on the upper side of the sheet is also possible.

[0038] In this example, the static elimination unit 301 employs both a method of contacting the sheet with the static elimination material and a non-contact method, but it is not limited to these. For example, a configuration employing only one of these methods is also acceptable.

[0039] (Configuration of the upper part of the static eliminator) The top surface 300A and front surface 300B of the static elimination device 300 constitute the exterior of the static elimination device 300. The front of the top surface 300A has a recess, in which a static elimination input section 330 and a grounding connector 360, described later, are provided. The front surface 300B consists of a door 382 and an upper front section 381 (see Figure 9). The door 382 is configured to be openable and closable by an opening and closing mechanism (not shown). The upper front section 381 is provided with a slanted section 381A. The front surface is located on the front side (opposite the direction indicated by the Y-axis arrow), and the user frequently works at the front of the device.

[0040] As shown in Figures 7 and 8, a static elimination input unit 330 is provided at the top and front of the static elimination device 300 for the user to input settings for the static elimination unit 301. 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 can be, for example, various input keys, a dial, or a touch panel. The user inputs the set 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 reception of the static elimination voltage value is not limited to the static elimination input unit 330; for example, input may be received via the operation unit 130 or an external computer. The external computer may be a smartphone or tablet owned 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 set value of the static elimination bias Vd and the ON or OFF switching status of the non-contact static elimination units 351 and 352. Furthermore, as will be described later, it is also possible to display that the adjustment mode is active 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, but may also be used to display the level of static elimination (static elimination level) as a numerical value in, for example, 10 levels.

[0041] A grounding connector 360 is provided on the support member 362. The housing frame 302 is the frame ground and is electrically grounded. As shown in Figure 9, the grounding connector 360 is in contact with the frame 302 of the static elimination device 300 and is electrically grounded. The grounding connector 360 has a bottom portion 360A and a side portion 360B. The bottom portion 360A is provided with a screw hole 360A1, which is screwed into a fixing screw 361 (see Figure 15). In this embodiment, a fixing screw 361 is also provided so that the terminals of objects that need to be grounded can be reliably connected to the grounding connector 360. The side portion 360B is connected to the bottom portion 360A and is positioned substantially perpendicular to the bottom portion 360A. The side portion 360B has a substantially circular hole 360B1 and can be gripped by a clip terminal. In this embodiment, the grounding connector 360 is a terminal having a structure for fixing or gripping the terminal of an earth wire connected to an object (for example, the potential measuring instrument 510 or conductive plate 500 shown in Figure 14). However, the grounding connector 360 is not limited to fixing or gripping the terminal of the earth wire of the object, but may also have a structure that allows the copper wire of the earth wire to be wrapped around it.

[0042] The grounding connector 360 is located at the upper front, allowing the user to easily ground or earth objects (such as the potential measuring instrument 510 or the conductive plate 500) that need to be grounded. It is preferable that the grounding connector 360 be located near the static elimination input unit 330. In this embodiment, the grounding connector 360 and the static elimination input unit 330 are located in a recess at the front of the top surface 300A. In other words, the grounding connector 360 and the static elimination input unit 330 are located on the same plane.

[0043] <Communication configuration of an image forming system equipped with a static elimination device> Using Figure 10, the communication configuration of the image forming system equipped with the static elimination device 300 in this embodiment will be explained. However, although various other devices such as motors and power supplies are connected to the image forming system in addition to those shown in the figure, their illustration and explanation are omitted here as they are not the essence of the invention.

[0044] Figure 10 is a block diagram showing the communication of the image forming system. The image forming apparatus 100 is equipped with a control unit 120. The cooling device 200 is equipped with a cooling control unit 220. The static elimination device 300 is equipped with a static elimination control unit 320. The paper discharge and stacking device 400 is equipped with a paper discharge and stacking control unit 420. The control unit 120 performs various controls of the image forming apparatus 100, such as image forming operations, and includes a CPU (Central Processing Unit) and has a memory 121 such as ROM, RAM, or a hard disk drive. The memory 121 stores various programs such as image forming 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 by the operation unit 130 or an external PC (not shown), and can operate the image forming apparatus 100 by executing various programs. Furthermore, the control unit 120, the cooling control unit 220, the static elimination control unit 320, and the paper discharge and stacking control unit 420 are connected via communication, and the cooling unit 201, the stacking unit 403, and other components can be operated via each control unit.

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

[0046] Furthermore, if an operation setting is made in the static elimination input section 330 of the static elimination device 300, communication is made from the static elimination control unit 320 to the control unit 120 of the image forming apparatus 100, and the image forming apparatus 100 can operate according to the setting.

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

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

[0049] <Explanation of the static elimination bias adjustment process for static elimination devices> The flow for adjusting the static elimination bias setting value of the static elimination device 300 in this embodiment will be explained with reference to the figures. First, the factors for adjusting the static elimination bias setting value will be explained with reference to Figures 11 and 12. Figure 11 is a graph showing the 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 Figure 6) of the static elimination device 300, and the vertical axis is the potential of the sheet surface measured by a potential measuring instrument after the static elimination process. The sheet surface is the surface on which the image was transferred in 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 0V, media A needs to have a static elimination bias set with a larger absolute value than media B and media C. In other words, the appropriate static elimination bias to keep 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 wide variety of sheet types. For example, there is a growing demand for image formation on sheets with high electrical resistance, such as transparent film, synthetic paper (film-type synthetic paper mainly made from polypropylene), and specialty paper (for example, recording material mainly made from limestone). The static elimination characteristics of these sheets also vary.

[0051] Figure 12 is a graph showing the static elimination characteristics of a high-resistance sheet A. The values ​​shown 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, the static elimination characteristics vary even for sheets of the same type. Factors causing this variation include changes in the state of the sheet and static elimination device due to changes in the printing environment such as humidity and temperature.

[0052] The range F shown in Figure 12 represents the amount of sheet charge that does not cause problems when the sheets are ejected and stacked. Even if a target static elimination bias setting value for sheet A is entered, the amount of sheet charge after static elimination will vary within the range of arrow Vp depending on the printing environment, etc. In such cases, there is a possibility that the amount of charge F will exceed the allowable range of sheet charge. In other words, even if static elimination characteristic data for the sheet to be image formed exists in the memory 121 or static elimination memory 321 mentioned above, due to variations in the static elimination characteristics of the sheet, the desired amount of sheet charge (range F in Figure 12) may not be achieved even after static elimination by the static elimination device 300. Therefore, in this embodiment, in order to set the amount of sheet charge 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 for adjusting the static elimination bias setting value Vd of the static elimination device 300 in this embodiment will be explained using Figures 13, 14, and 15. First, before explaining the adjustment flow of the static elimination bias setting value, the configuration for measuring the charge amount of the sheet in this embodiment will be explained using Figures 14 and 15. Figure 14 is a perspective view showing the configuration for measuring the charge amount of the sheet, which is set as the adjustment flow, and Figure 15 is an enlarged upper view showing the connector part of the configuration for measuring the charge amount of the sheet.

[0054] To reliably measure the charge level of a sheet discharged into the output tray 401, a grounded conductive plate 500 on which the sheet is placed and a grounded potential measuring instrument 510 are required. When measuring the charge level of a sheet, the user grounds the conductive plate 500 and the potential measuring instrument 510 using the grounding connector 360 of the static eliminator 300. Specifically, the conductive plate 500 is electrically connected to a cable 501, and the terminal 501A of the cable 501 is connected to the grounding connector 360 (connection part) by a fixing screw 361. At this time, the terminal 501A of the cable 501 is sandwiched between the fixing screw 361 and the screw hole 360A1. Similarly, the potential measuring instrument 510 is electrically connected to a cable 511, and the clip terminal 511A of the cable 511 is connected to the grounding connector 360 (connection part). At this time, the clip terminal 511A of the cable 511 clamps the hole 360B1 of the grounding connector 360. In other words, the grounding connector 360 is connectable to terminals, and the user attaches terminals 501A or clip terminals 511A to the grounding connector 360. This eliminates the need for the user to separately prepare a grounding environment for grounding the conductive plate 500 or the potential measuring instrument 510. However, depending on the type of potential measuring instrument, grounding of the potential measuring instrument may not always be necessary. The conductive plate is made of a material such as stainless steel or aluminum with an electrical resistance of approximately 100 μΩ·cm or less.

[0055] Next, using Figure 13, we will explain the adjustment flow for determining the static elimination bias setting value Vd. In this embodiment, it is possible to perform a normal mode in which static elimination of the sheet S is performed as part of the 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 performed when the appropriate static elimination bias setting value for the sheet used in the print job is unknown. In the static elimination adjustment mode, a test print is performed. In the test print, a pre-set test toner image (test pattern image) is formed on the sheet. Then, static elimination processing is performed on the sheet in which the test toner image has been formed, using the static elimination bias value set by the user, and output to the output tray 401.

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

[0057] First, the static elimination input unit 330 of the static elimination device 300 accepts the user's selection of a static elimination adjustment mode, and the adjustment flow begins. Once the static elimination adjustment mode starts, the static elimination control unit 320 obtains a guideline static elimination bias setting value from the aforementioned memory 121 or static elimination memory 321, according to the type of sheet that has already been set (Step S1).

[0058] Next, the 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 sheet does not have a set value registered in memory, the user may set it using the static elimination input unit 330 (step S2).

[0059] When the static elimination bias setting value is set, a signal is communicated from the static elimination control unit 320 to the control unit 120, and the image forming apparatus 100 performs a test print, and one sheet that has been statically eliminated with the set static elimination bias setting value is output to the output tray 401 (step S3).

[0060] The sheet output to the output tray 401 has its charge level measured by the user. As described above, the user places the sheet to be measured on the grounded conductive plate 500 without changing its front or back side after it has been output, and measures the charge level with the potential measuring instrument 510. (Step S4) Next, the user confirms that the value of the potential meter 510 is less than or equal to the desired charge amount of ±F[V]. In this embodiment, the desired charge amount is approximately ±200V (step S5).

[0061] If the measurement result falls within the desired charge range, the static elimination input unit 330 sets the end of the static elimination adjustment and terminates the adjustment flow.

[0062] If the measurement result falls outside the desired charge range, the user adjusts the static elimination bias setting value again. In this embodiment, as shown in Figure 6, the static elimination high-voltage power supply 343 applies a negative voltage to the static elimination roller 341. Therefore, if the sheet is not sufficiently statically eliminated, the top surface of the sheet measured by the potential meter will be negatively charged. Conversely, if the voltage applied to the static elimination roller is excessive, the polarity of the sheet after static elimination reverses, and the top surface of the sheet measured by the potential meter will be positively charged. Therefore, if the sheet charge is outside the negative potential range, adjust the setting value in the negative direction from the guideline static elimination bias setting value (increase the absolute value), and if the sheet charge is outside the positive potential range, adjust the setting value in the positive direction from the guideline static elimination bias setting value (decrease the absolute value) (step S6). Then, based on the adjustment direction, the user re-enters the static elimination bias setting value, performs a test print, and repeats the measurement of the sheet charge until the sheet charge is within the desired range. If the measurement result is within the desired charge range, the static elimination input unit 330 sets the end of the static elimination adjustment and terminates the adjustment flow.

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

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

[0065] A modified version of the previously described Embodiment 1 will now be explained. In this embodiment, the support member 362 supporting the static elimination input unit 330 may be connected to the frame 302 and electrically grounded. Also, as shown in Figure 16, a grounding connector 360 may be configured on the top surface of the static elimination device 300 at a different location from the static elimination input unit 330. The position of the grounding connector 360 should preferably be within reach of the user. In this embodiment, the front-to-rear length L of the static elimination device 300 is 700 mm, and it is preferable that the grounding connector 360 be positioned on the top surface in a range of 460 mm from the front, which is approximately 2 / 3 of the length.

[0066] Furthermore, as shown in Figure 17, the grounding connector 360 may be located on the front of the static elimination device 300 at a different position from the static elimination input unit 330. In other words, the grounding connector 360 and the static elimination input unit 330 only need to be located at the upper front of the static elimination device 300. To put it another way, the grounding connector 360 and the static elimination input unit 330 each only need to be located within a 460 mm range from the front of the top surface 300A or at the upper front surface 381 of the front surface 300B.

[0067] The placement of the grounding connector 360 near the static elimination input unit 330 ensures that the grounding connector 360 is within reach of the user even when standing in front of the static elimination input unit 330. This simplifies the adjustment process, eliminating the need to move when measuring the charge level of the sheet and inputting the static elimination bias setting value during the static elimination bias adjustment process. In addition, the user can input the static elimination setting value to the static elimination input unit 330 while checking the measurement results of the potential measuring instrument 510.

[0068] Furthermore, in this embodiment, the devices adjacent to the static elimination device 300 are the cooling device 200 and the paper discharge and stacking device 400, but the embodiment is not limited to these. For example, a combination of devices such as a device for correcting the curl amount of the sheet or an inspection device for detecting printed image defects may be adjacent to the static elimination device 300 upstream and downstream in the sheet transport direction.

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

[0070] Figure 18 is a perspective view showing the configuration of Embodiment 2. A static elimination input section 330 and a grounding connector 360 are provided at the front upper part of the static elimination device 300. An electrically grounded sheet mounting surface 370 is provided on the top surface of the static elimination device 300. The sheet mounting surface 370 is rectangular in shape and larger than the size of the sheet placed on it. The sheet mounting surface 370 is connected to the frame 302 shown in Figure 9. In Embodiment 2, since the static elimination device 300 has an electrically grounded sheet mounting surface 370, the user does not need to prepare a conductive plate 500. The sheet mounting surface is electrically conductive and is made of a material with an electrical resistance of approximately 100 μΩ·cm or less, such as stainless steel or aluminum. Preferably, the sheet mounting surface is flat and free of irregularities. Preferably, the grounding connector 360 is located in front of the sheet mounting surface 370.

[0071] The sheet mounting surface 370 is used as the surface on which the test-printed sheet is placed in the static elimination bias setting adjustment flow described in Example 1. In addition, the cable of the potential measuring instrument 510 can be connected and grounded using the grounding connector 360. This eliminates the need for the user to prepare the conductive plate 500. Furthermore, it eliminates the need for the user to prepare a grounding environment for grounding the potential measuring instrument 510.

[0072] The placement of the grounding connector 360 and the sheet mounting surface 370 near the static elimination input unit 330 ensures that the grounding connector 360 and the sheet mounting surface 370 are within reach of the user even when standing in front of the static elimination input unit 330. This facilitates the adjustment 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 measuring instrument 510.

[0073] A modified example of the above-described embodiment 2 is shown in Figure 19. An electrically grounded sheet mounting surface 370 is provided on the top surface of the static elimination device 300. The sheet mounting surface 370 also serves as the exterior of the static elimination device 300, and may be, for example, a colored steel plate of the same color as the other exterior parts.

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

[0075] Figure 20 is a perspective view showing the configuration of Embodiment 3. A static elimination input section 330 and a grounding connector 360 are provided at the front upper part of the static elimination device 300. A cooling device 200 is connected adjacent to the static elimination device 300 upstream in the sheet transport direction of the static elimination device 300. A paper discharge and stacking device 400 is connected adjacent to the static elimination device 300 downstream in the sheet transport direction of the static elimination device 300.

[0076] The top surface 200A of the cooling device 200 is provided with an electrically grounded sheet mounting surface 270. The sheet mounting surface 270 is rectangular and larger than the sheet placed on it. The sheet mounting surface is electrically conductive and is made of a material with an electrical resistance of approximately 100 μΩ·cm or less, such as stainless steel or aluminum. Preferably, the sheet mounting surface is flat and free of irregularities. Preferably, the grounding connector 360 is located in the area to the right of the center of the static eliminator 300. In other words, the placement of the grounding connector 360 near the sheet mounting surface 270 of the cooling device 200 improves user operability.

[0077] The sheet mounting surface 270 is used as the surface on which the test-printed sheet is placed in the static elimination bias setting adjustment flow described in Example 1. In addition, it is possible to connect the cable of the potential measuring instrument 510 using the grounding connector 360 to ground it. This eliminates the need for the user to prepare the conductive plate 500. Furthermore, it eliminates the need for the user to prepare a grounding environment for grounding the potential measuring instrument 510.

[0078] The placement of the grounding connector 360 and the sheet mounting surface 270 near the static elimination input unit 330 ensures that the grounding connector 360 and the sheet mounting surface 270 are within reach of the user even when standing in front of the static elimination input unit 330. This facilitates the adjustment 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 measuring instrument 510.

[0079] As a modification of the above-described embodiment 3, an electrically grounded sheet mounting surface may be provided on the top surface 400A of the paper discharge and stacking device 400, which is adjacent to the downstream side of the static elimination device 300 in the transport direction. In this case, it is preferable that the grounding connector 360 is located in a region to the left of the center of the static elimination device.

[0080] Furthermore, in this embodiment, the devices adjacent to the static elimination device 300 are the cooling device 200 and the paper discharge and stacking device 400, but the embodiment is not limited to these. For example, a device for correcting the curl amount of the sheet or an inspection device for detecting printed image defects may be adjacent to the static elimination device 300 upstream and downstream in the sheet transport direction. [Explanation of Symbols]

[0081] 100 Image forming apparatus 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 Grounding Connector 361 Fixing screw 362 Support member 370 Sheet mounting surface 400 Paper output and stacking device 401 Paper Output Tray 500 conductive plates 510 Potential Measuring Instrument

Claims

1. A static elimination device for removing static electricity from a sheet that has been image-formed by an image forming apparatus, A static elimination unit for removing static electricity from a sheet that has been image-formed by an image forming apparatus, A receiving unit that receives the setting of the static elimination level of the static elimination unit, A grounded terminal provided on the top or front surface of the static eliminator, Equipped with, A static elimination device characterized by the following features.

2. The static elimination device includes an input section into which user instructions are input. The input unit is located on the top surface or front surface of the static elimination device. The static elimination device according to feature 1.

3. The terminals are located on the top surface of the static elimination device and are positioned within a range of 2 / 3 of the length of the device from the front in the depth direction. The static elimination device according to feature 2.

4. The static elimination unit comprises a first static elimination roller and a second static elimination roller, and the sheet is statically eliminated in a state where it is in contact with the sheet at the nip portion formed by the first and second static elimination rollers. The static elimination device according to feature 1.

5. The terminal includes a bottom portion having a screw hole that can be connected to a fixing screw. The static elimination device according to feature 1.

6. The terminal is positioned substantially perpendicular to the bottom surface and includes a side surface with a hole that can be connected to the terminal. The static elimination device according to feature 5.

7. The top surface includes a grounded conductive plate. The static elimination device according to feature 1.

8. The static elimination device includes an input section into which user instructions are input. The input section and the terminal are positioned in front of the conductive plate. The static elimination device according to feature 7.

9. The aforementioned terminals are used to ground the conductive plate on which the sheet is placed or the potential measuring instrument used to measure the charge level of the sheet when measuring the charge level of the sheet. The static elimination device according to feature 1.

10. A static elimination device according to any one of claims 1 to 9, The image forming apparatus comprises the above-mentioned image forming apparatus, An image forming system characterized by the following features.

Images