Static elimination device and image forming system

Abstract

This invention provides a static elimination device and an image forming system that reduce the frequency of interruptions to printing operations due to maintenance of the non-contact static elimination unit. [Solution] A static elimination device connected to an image forming apparatus equipped with an image forming unit for forming an image on a sheet, comprising: an electrode unit for generating ions, a non-contact static elimination unit for eliminating static electricity from the sheet in a non-contact manner for eliminating static electricity from the sheet on which the image has been formed by the image forming unit; and a control unit that performs a detection process for detecting whether or not maintenance of the electrode unit is required, wherein the control unit performs the detection process between the time an instruction is given for the image forming apparatus to transition from a first state to a second state with lower power consumption than the first state, and the time the image forming apparatus transitions to the second state.

Description

[Technical Field]

[0001] This invention relates to an anti-static device and an image forming system. [Background technology]

[0002] In image forming apparatuses that form images on sheets, the sheets can become electrically charged during image formation, causing them to stick together after being discharged, resulting in poor loading. Therefore, an image forming system equipped with a non-contact static elimination unit that removes static electricity from the sheets without contact has been proposed. However, continuous use of the non-contact static elimination unit can cause dust and organic matter from the air to deposit on the electrodes of the unit, reducing its static elimination performance. For this reason, it is desirable that the electrodes be maintained at appropriate intervals. In Patent Document 1, a detection process is performed to determine whether or not maintenance of the electrodes is necessary when the number of sheets that have been statically eliminated by the non-contact static elimination unit reaches a threshold. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2024-107617 [Overview of the project] [Problems that the invention aims to solve]

[0004] However, jobs cannot be executed while the electrode section is being maintained. Therefore, if maintenance of the electrode section is required as a result of detection processing in the middle of a continuous job, the printing operation must be interrupted, which reduces the user's work efficiency. Thus, the present invention aims to provide a static elimination device and an image forming system that reduce the frequency of interruptions to the printing operation due to maintenance of the non-contact static elimination section. [Means for solving the problem]

[0005] One embodiment of the present invention is a static elimination device connected to an image forming apparatus equipped with an image forming unit for forming an image on a sheet, the device comprising: an electrode unit for generating ions, a non-contact static elimination unit for eliminating static electricity from the sheet in a non-contact manner for eliminating static electricity from the sheet on which the image has been formed by the image forming unit; and a control unit that performs a detection process for detecting whether or not maintenance of the electrode unit is required, wherein the control unit performs the detection process between the time the image forming apparatus is instructed to transition from a first state to a second state having less power consumption than the first state, and the time the image forming apparatus transitions to the second state.

[0006] Another embodiment of the present invention is an image forming system comprising: an image forming unit that forms an image on a sheet; an electrode unit that generates ions and removes static electricity from the sheet in a non-contact manner from the sheet on which the image has been formed by the image forming unit; and a control unit that performs a detection process to detect whether or not maintenance of the electrode unit is required, wherein the control unit performs the detection process between the time an instruction is given to transition the image forming system from a first state to a second state which consumes less power than the first state, and the time the image forming system transitions to the second state. [Effects of the Invention]

[0007] According to the present invention, it is possible to implement a static elimination device and an image forming system that reduce the frequency of interruptions to printing operations due to maintenance of the non-contact static elimination unit. [Brief explanation of the drawing]

[0008] [Figure 1] Schematic diagram of an image forming system. [Figure 2] Schematic diagram of an anti-static device. [Figure 3] A diagram illustrating an image formation system. [Figure 4] Perspective views of the upper and lower units with the upper unit closed. [Figure 5] A perspective view of the upper and lower units with the upper unit in the open position. [Figure 6] Perspective view of the transport guide for the non-contact static elimination unit. [Figure 7] Control block diagram of the image forming apparatus and static elimination apparatus. [Figure 8] Screen display of the user control panel. [Figure 9] Control flowchart for the static elimination control unit. [Figure 10] Control flowchart for the static elimination control unit. [Modes for carrying out the invention]

[0009] Embodiments of the present invention will be described below with reference to the figures. Unless otherwise specifically stated, the dimensions, materials, and relative positions of the components of the image forming apparatus and static eliminator are not intended to limit the scope of the present invention to those components alone. Furthermore, components denoted by the same reference numerals in each figure have the same configuration or function, and redundant explanations of these components have been omitted as appropriate.

[0010] (Example 1) <Schematic configuration of an image forming apparatus> Figure 1 is a diagram of the configuration of the image forming system 300 in this embodiment. The image forming system 300 comprises an image forming apparatus 100 for forming an image on a sheet S, and a static elimination apparatus 200 for eliminating the electric charge on the sheet surface. Details of the static elimination apparatus 200 are omitted in the schematic diagram of the image forming system 300 in Figure 1. The configuration of the static elimination apparatus 200 will be described later (see Figure 2).

[0011] First, the schematic configuration of the image forming apparatus 100 will be described. The image forming apparatus 100 forms an image on a sheet using an electrophotographic process. The image forming apparatus 100 includes four image forming units 11Y, 11M, 11C, and 11K that form images of yellow (Y), magenta (M), cyan (C), and black (K), respectively, as a plurality of image forming units. These image forming units 11Y, 11M, 11C, and 11K are arranged in a row along the moving direction of the image transfer surface disposed substantially horizontally on the intermediate transfer belt 6 described later. The image forming unit 11 includes a photosensitive drum 1 (1Y, 1M, 1C, 1K), a charging device 2 (2Y, 2M, 2C, 2K), an exposure device 3 (3Y, 3M, 3C, 3K), a developing device 4 (4Y, 4M, 4C, 4K), and a primary transfer roller 5 (5Y, 5M, 5C, 5K).

[0012] As shown in FIG. 1, the photosensitive drums (latent image carriers) 1Y, 1M, 1C, and 1K rotate in the direction of arrow A. The surfaces of the photosensitive drums 1Y, 1M, 1C, and 1K are uniformly charged by the charging devices 2Y, 2M, 2C, and 2K. The exposure devices 3Y, 3M, 3C, and 3K perform exposure based on image information to form an electrostatic latent image on the surfaces of the photosensitive drums 1Y, 1M, 1C, and 1K. The developing devices 4Y, 4M, 4C, and 4K contain toners of yellow (Y), magenta (M), cyan (C), and black (K) colors, respectively. The developing devices 4Y, 4M, 4C, and 4K develop the electrostatic latent image with their respective toners, and toner images are formed on the surfaces of the respective photosensitive drums 1Y, 1M, 1C, and 1K. In this embodiment, the image forming apparatus 100 uses a reversal development method in which toner is attached to the exposure portion of the electrostatic latent image for development.

[0013] The intermediate transfer belt 6 is arranged to abut against the surfaces of the photosensitive drums 1Y, 1M, 1C, and 1K. The intermediate transfer belt 6 is stretched over a plurality of stretching rollers 20, 21, 22, 23, 24, and 25 and rotates in the direction of arrow G at a rotational speed of 150 to 470 mm / sec. In this embodiment, the stretching roller 20 is a tension roller configured to control the tension of the intermediate transfer belt 6 to be constant. The stretching roller 22 is a driving roller of the intermediate transfer belt 6. The stretching roller 21 is an inner roller for secondary transfer. The outer roller 9 for secondary transfer sandwiches and conveys the sheet S at the secondary transfer nip (secondary transfer portion) between the outer roller 9 and the intermediate transfer belt 6.

[0014] The primary transfer rollers 5Y, 5M, 5C, and 5K are arranged opposite to the respective photosensitive drums 1Y, 1M, 1C, and 1K via the intermediate transfer belt 6, and form a primary transfer nip (primary transfer portion) between the respective photosensitive drums 1Y, 1M, 1C, and 1K. In synchronization with the conveyance of the respective color toner images on the surfaces of the photosensitive drums 1Y, 1M, 1C, and 1K to the primary transfer nip portion, a transfer bias controlled at a constant voltage with a polarity opposite to that of the toner image is applied to the primary transfer rollers 5Y, 5M, 5C, and 5K. Thereby, the toner images on the respective photosensitive drums 1Y, 1M, 1C, and 1K are transferred onto the intermediate transfer belt 6 (primary transfer).

[0015] Near the intermediate transfer belt 6, a belt reading sensor 17 is provided. The belt reading sensor 17 reads the image transferred onto the intermediate transfer belt 6. The belt reading sensor 17 is, for example, an optical sensor, and irradiates light onto the image on the intermediate transfer belt 6 and receives the reflected light to read the image. For example, the belt reading sensor 17 reads an adjustment image for adjusting the image forming conditions formed on the intermediate transfer belt 6. The main body CPU 61 described later analyzes the reading result of the adjustment image by the belt reading sensor 17 and performs calibration by feeding back to the image forming conditions.

[0016] The sheet S stored in the cassette 28 is transported to the register roller 8 by the feed roller and the like, and temporarily stopped. The register roller 8 then transports the sheet S to the secondary transfer section in synchronization with the toner image on the intermediate transfer belt 6 being transported to the secondary transfer nip. The pre-secondary transfer transport guide 14 improves the transport accuracy when transporting the sheet S to the secondary transfer section. The high-voltage application unit 10 applies a constant-voltage controlled transfer bias with the opposite polarity to the toner image to the outer roller 9 for secondary transfer. As a result, the toner image on the intermediate transfer belt 6 is transferred to the sheet S (secondary transfer). In this embodiment, since the toner has a negative polarity, a positive voltage is applied to the outer roller 9 for secondary transfer. On the other hand, the tension roller 21, which is the inner roller for secondary transfer, is electrically grounded. However, the high-voltage application unit 10 may apply a constant-voltage controlled transfer bias with the same polarity as the toner to the tension roller 21, which is the inner roller for secondary transfer, and the outer roller 9 for secondary transfer may be electrically grounded.

[0017] The sheet S onto which the toner image has been transferred is transported by the pre-fixing transport device 31, which has a rotating belt. The fixing device 30 heats and pressurizes the sheet S to fix the toner image onto the sheet S. The belt cleaning device 12 electrostatically collects and cleans the residual secondary transfer toner that remains on the intermediate transfer belt 6 without being transferred to the sheet S. The cleaned intermediate transfer belt 6 is repeatedly used for image formation.

[0018] The main display unit 66 is located on the exterior of the image forming system 300. The main display unit 66 may be directly fixed to the exterior, or it may be connected to the device by a cable and placed on top of the device. Alternatively, the main display unit 66 may not be connected to the main device by a cable and may communicate wirelessly using Bluetooth®.

[0019] <Outline configuration of a static elimination device> Figure 2 shows a schematic configuration of the static elimination device 200. Figure 3 shows the image forming system 300. The static elimination device 200 is located downstream of the image forming apparatus 100 with respect to the sheet transport direction. In the secondary transfer described above, a high voltage of positive polarity is applied to the outer roller 9 for secondary transfer (see Figure 1). As a result, the sheet S that has passed through the secondary transfer section has a positive charge on its lower surface and a negative charge on its upper surface due to dielectric polarization. Therefore, if the sheets are loaded onto the discharge tray 60 without static elimination treatment, the contact surfaces of the loaded sheets will have opposite polarities, and there is a risk that the sheets will stick together due to electrostatic force. In this embodiment, the static elimination device 200 removes the charge from the sheet surface (upper and lower surface) using a contact static elimination unit 57 and a non-contact static elimination unit 58 to prevent the sheets from sticking together due to electrostatic force.

[0020] The static eliminator 200 may be directly connected to the image forming apparatus 100, or it may be connected to the image forming apparatus 100 via a sheet processing device such as an inserter. The image forming apparatus 100 and the static eliminator 200 may be integrally formed to constitute the image forming apparatus 100. Alternatively, the image forming apparatus 100 and the static eliminator 200 may be integrally formed to constitute the static eliminator 200. In other words, the housings of the image forming apparatus 100 and the static eliminator 200 may be the same, or they may be separate.

[0021] The static elimination device 200 consists of a housing 59, a contact static elimination unit 57, a non-contact static elimination unit 58, a transport guide 53, and a control unit (not shown) that controls the entire static elimination device 200. Furthermore, the static elimination device 200 includes a static elimination operation unit 54 and a static elimination display unit 56. The sheet S transported from the image forming apparatus 100 has its charge roughly removed by the contact static elimination unit 57, which removes static charge from the sheet while in contact with the sheet. Next, the sheet S has any remaining charge that could not be removed by the contact static elimination unit 58 removed by the non-contact static elimination unit 58, and is discharged outside the static elimination device 200. Details of the contact static elimination unit 57, the non-contact static elimination unit 58, and the static elimination operation unit 54 will be described later.

[0022] The static elimination indicator unit 56 has an LED and, as shown in Figure 3, is located on the top surface 200a (top surface of the device) of the exterior covering the housing 59. Alternatively, the static elimination indicator unit 56 may be located on the front surface 200b (front of the device) of the exterior of the static elimination device 200. The front surface 200b is the surface of the static elimination device 200 facing the front of the device, and the front surface 200b includes inclined surfaces that intersect with the vertical direction. By positioning the static elimination indicator unit 56 on the top surface 200a or the front surface 200b of the exterior of the static elimination device 200, the user can check the display content when using the static elimination device 200. In other words, the static elimination indicator unit 56 only needs to be located on the outside of the exterior. For example, the static elimination indicator unit 56 may be directly fixed to the exterior, or it may be connected to the device by a cable and placed on top of the device. Furthermore, the static elimination indicator unit 56 may not be connected to the main body of the device by a cable, and wireless communication via Bluetooth may be used. The static elimination indicator unit 56 switches between being lit and unlit depending on the state of the ionizer 52 of the non-contact static elimination unit 58.

[0023] In this embodiment, the static elimination indicator unit 56 has an LED, but it is not limited to this and may be a display such as a liquid crystal. Furthermore, the static elimination indicator unit 56 may display information not only about the non-contact static elimination unit 58, but also about the contact static elimination unit 57.

[0024] The static elimination device 200 is provided with a door 250 (Figure 3) that forms the front of the device, and the door 250 is configured to be openable and closable relative to the housing 59 by an opening and closing mechanism (not shown). The opening and closing of the door 250 of the static elimination device 200 is detected by a door sensor 202. By opening the door 250, the user can access the upper unit 401 and the lower unit 402. Specifically, as shown in Figure 2, the upper unit 401 is equipped with a static elimination opposing roller 51 and an ionizer 52a. The lower unit 402 is equipped with a static elimination roller 50, an ionizer 52b and a transport guide 53. The upper unit 401 is also configured to be openable and closable relative to the lower unit 402.

[0025] Figure 4 shows a perspective view of the upper unit 401 and lower unit 402 in the closed state. Figure 5 shows a perspective view of the upper unit 401 and lower unit 402 in the open state. The upper unit 401 has an upper housing 401a made of sheet metal, and the ionizer 52a is fixed to the upper housing 401a. The lower unit 402 has a lower housing 402a made of sheet metal, and the ionizer 52b is fixed to the lower housing 402a. The lower unit 402 is fixed to the housing 59 of the static elimination device 200 so as not to move. On the other hand, the upper unit 401 is provided so as to be rotatable around a pivot axis 405 relative to the lower unit 402. The upper unit 401 is provided with a handle 406. Since the upper unit 401 rotates inside the housing 59, the range in which the upper unit 401 can rotate is restricted by the height of the top surface of the housing 59. In other words, the upper unit 401 is rotatable from a closed position until it contacts the top surface of the housing 59.

[0026] To maintain the static elimination capability of the ionizer 52, the user must perform maintenance on the electrode section of the ionizer 52. Since the upper unit 401 is configured to rotate relative to the lower unit 402, the user can access the electrode section.

[0027] Figure 6 is a perspective view of the conveyor guide 53 that guides the sheet. The conveyor guide 53 has two interlocking holes 532 that interlock with the protrusions 407, described later, located outside the conveyor path in the width direction perpendicular to the sheet conveying direction. On the other hand, as shown in Figure 5, the lower unit 402 has two protrusions 407 that protrude upward outward from the conveyor path in the width direction perpendicular to the sheet conveying direction. The conveyor guide 53 is positioned on the lower unit 402 by interlocking each of the two interlocking holes 532 of the conveyor guide 53 with the protrusions 407 of the lower unit 402. The positioned conveyor guide 53 is then detachably attached to the lower housing 402a of the lower unit 402 by screws 408, which are fixing members located on the front side of the device. However, the conveyor guide 53 may also be configured to be rotatable relative to the lower unit 402 and may be fixed to the lower unit 402 by engaging members, not limited to screw fastening.

[0028] In the configuration described above, when cleaning the static elimination needle 520 of the ionizer 52a, the user first opens the door 250 and rotates the upper unit 401 upward using the handle 406. This allows the user to access the static elimination needle 520 of the ionizer 52a. When cleaning the static elimination needle of the ionizer 52b, after rotating the upper unit 401 upward, the transport guide 53 is removed from the lower unit 402. This allows the user to access the static elimination needle 520 of the ionizer 52b and perform maintenance (cleaning) on ​​the ionizer 52 of the non-contact static elimination unit 58.

[0029] Furthermore, when the user rotates the upper unit 401 upward, the static elimination roller 50 and the static elimination opposing roller 51 are separated. Therefore, when a sheet gets jammed inside the static elimination device, the user can remove the jammed sheet by rotating the upper unit 401.

[0030] <Contact Static Elimination Unit> As shown in Figure 2, the contact static elimination unit 57 includes a static elimination roller 50 and a static elimination opposing roller 51, which are contact static elimination means, and a high-voltage substrate 55 that generates high voltage applied to the static elimination roller 50. The static elimination roller 50 consists of an elastic layer of ion-conductive foamed rubber and a core metal. The static elimination roller 50 has an outer diameter of 20-25 mm, and when measured in a 23°C, 50% RH environment with a voltage of 2 kV applied, the resistance value of the static elimination roller 50 is 1 × 10⁻¹⁶. 5 ~1 × 10 8 It is Ω and is the same material as the outer roller 9 for secondary transfer. The static elimination roller 50 is subjected to a static elimination voltage, which is a DC voltage controlled by a constant voltage by the high-voltage substrate 55. In this embodiment, as described above, the sheet S is transported to the static elimination device 200 with the upper surface of the sheet negatively charged and the lower surface of the sheet positively charged. Therefore, the high-voltage substrate 55 applies a negative voltage to the static elimination roller 50 which is positioned on the lower side of the sheet.

[0031] The static elimination opposing roller 51 is made of stainless steel (SUS) and is electrically grounded (connected to ground). The static elimination opposing roller 51 uses a roller with an outer diameter of 20 to 25 mm and is positioned opposite the static elimination roller 50.

[0032] The static elimination roller 50 and the static elimination opposing roller 51 form a static elimination nip section. The static elimination roller pair, consisting of the static elimination roller 50 and the static elimination opposing roller 51, is in contact with the sheet S and roughly removes the static charge from the sheet. The contact static elimination section 57 in this embodiment has a high static elimination effect because it is in contact with the sheet S and applies voltage directly. On the other hand, the contact static elimination section 57 has the characteristic that the surface potential of the sheet S after static elimination varies greatly, and static elimination tends to be uneven. Therefore, in the static elimination device 200 of this embodiment, a non-contact static elimination section 58 is provided downstream of the contact static elimination section 57 in the sheet transport direction.

[0033] In this embodiment, the static elimination opposing roller 51 rotates by being driven by a static elimination drive motor (not shown) and conveys the sheet S held by the static elimination nip. In this embodiment, the static elimination roller 50 is subjected to a negative voltage by the high-voltage substrate 55 and the static elimination opposing roller 51 is electrically grounded, but this is not limited to this. The static elimination opposing roller 51 may be subjected to a positive voltage by the high-voltage substrate 55 and the static elimination roller 50 may be electrically grounded.

[0034] <Non-contact static elimination unit> The non-contact static elimination unit 58 is composed of ionizers 52 (52a, 52b), which are non-contact static elimination means. In this embodiment, the ionizer 52a is a bar type that extends in the width direction perpendicular to the sheet transport direction, and the ionizer 52a is equipped with a static elimination needle 520 that generates ions and an ionizer control unit 521 that controls the ionizer. The ionizer 52b has the same configuration as the ionizer 52a. The ionizers 52 are positioned above and below the transport guide 53. The ionizer 52a is positioned above the transport guide 53, and the ionizer 52b is positioned below the transport guide 53. An AC bias is applied to the ionizer 52, and positive and negative ions are alternately emitted by corona discharge. Therefore, it is possible to simultaneously eliminate residual charge on both sides of the sheet S at the contact static elimination unit 57, regardless of the polarity direction of the residual charge on the sheet S. The static elimination effect of the sheet S by the non-contact static elimination unit 58 in this embodiment is smaller than that of the contact static elimination unit 57, but the surface potential of the sheet S after static elimination treatment has less variation. Therefore, the non-contact static elimination unit 58 can equalize the surface potential of the sheet S, which has become uneven due to the contact static elimination unit 57. The static elimination needle 520 in this embodiment is an example of an electrode part.

[0035] The transport guide 53 is a member for guiding the sheet and consists of an upper transport guide 53a positioned opposite the upper surface of the sheet and a lower transport guide 53b positioned opposite the lower surface of the sheet. In the vertical direction, the transport guide 53 is positioned below the ionizer 52a located in the upper unit 401 and above the ionizer 52b located in the lower unit 402. That is, in the vertical direction, the transport guide 53 is positioned between the ionizer 52a and the ionizer 52b. The sheet that has passed through the static elimination roller pair, which consists of a static elimination roller 50 and a static elimination opposing roller 51, is transported between the upper transport guide 53a and the lower transport guide 53b. The upper transport guide 53a and the lower transport guide 53b are made of an insulating resin synthesized from PC (polycarbonate) and ABS (acrylonitrile-butadiene-styrene). The volume resistivity of the transport guide in this embodiment is 1 × 10⁻⁶ 14 It is Ω·cm.

[0036] Figure 6 shows a perspective view of the transport guide 53. The transport guide 53a is provided with openings 53c so that ions generated from the static elimination needle 520, which is the ion emission part, are not physically shielded by the transport guide 53. Specifically, the upper transport guide 53a has multiple openings 53c arranged in the width direction perpendicular to the sheet transport direction. The lower transport guide 53b is similarly provided with multiple openings. The upper transport guide 53a and the lower transport guide 53b are fixed to each other by multiple screws 531 provided at both ends in the width direction, forming a single guide unit (transport guide 53).

[0037] In this embodiment, an ionizer 52 is used as the non-contact static elimination unit, but this is not the only option. For example, an AC Corotron method that applies high voltage to a wire may be used as the non-contact static elimination unit. Also, in this embodiment, the ionizer 52 is positioned on the upper and lower sides of the sheet, but this is not the only option. For example, the ionizer 52 may be positioned on only one side of the sheet, either the upper or lower side. Furthermore, the applied high voltage may be a DC voltage instead of an AC voltage.

[0038] <Configuration of the static elimination operation unit> In this embodiment, the static elimination device 200 is equipped with two static elimination units: a contact static elimination unit 57 and a non-contact static elimination unit 58. These two units eliminate static electricity from the sheet. However, the static elimination device 200 can also eliminate static electricity from the sheet by operating only the non-contact static elimination unit 58 without operating the contact static elimination unit 57. For example, for sheets such as plain paper with low electrical resistance, it is possible to sufficiently eliminate static electricity from the sheet by performing static elimination using only the non-contact static elimination unit 58 without using the contact static elimination unit 57. On the other hand, for sheets such as synthetic paper with high electrical resistance, it is preferable to eliminate static electricity from the sheet using both the contact static elimination unit 57 and the non-contact static elimination unit 58. Therefore, the user can arbitrarily change the settings of the static elimination device 200 using the static elimination operation unit 54 according to the type of sheet to be printed in the job.

[0039] The static elimination operation unit 54 is located on the top surface 200a (top surface of the device) of the housing of the static elimination device 200. Alternatively, the static elimination operation unit 54 may be located on the front surface 200b (front surface of the device) of the housing of the static elimination device 200. In this embodiment, the static elimination operation unit 54 includes a mode lever 54a and a dial 54b. The mode lever 54a is a selector switch for manually switching between "ON" and "OFF" (enabled and disabled) the voltage application to the static elimination roller 50 by the high-voltage substrate 55. The sheet is transported even when the mode lever 54a is in the OFF position. Furthermore, the non-contact static elimination unit 58 performs static elimination even when the mode lever 54a is set to OFF.

[0040] The dial 54b is a thumb rotary switch for manually setting the voltage value applied to the static elimination roller 50 by the high-voltage substrate 55. In this embodiment, the static elimination operation unit is equipped with two manual setting units, the mode lever 54a and the dial 54b, so that the user can change the setting of the mode lever without changing the setting of the dial 54b.

[0041] However, the voltage value applied to the static elimination roller 50 is not limited to manual setting by the user. The image forming apparatus 100 may transmit the sheet type to the static elimination device 200, and the static elimination CPU 82 (Figure 7) of the static elimination device 200 may determine the voltage value applied to the static elimination roller 50 based on the sheet type. Alternatively, the static elimination device 200 may be equipped with a detection roller or surface potential sensor to detect the amount of charge on the sheet, measure the amount of charge on the sheet after image formation, and the static elimination CPU 82 may determine the voltage value applied to the static elimination roller 50 according to the measured amount of charge on the sheet. Furthermore, the method for setting the voltage value applied to the static elimination roller 50 may be selectable between manual setting by the user and automatic setting by measuring the amount of charge on the sheet using a detection roller or the like.

[0042] <Image Forming System Block Diagram> Figure 7 is a block diagram showing the electrical configuration of the image forming apparatus 100 and the static elimination device 200. First, the configuration of the image forming apparatus 100 will be described. The image forming apparatus 100 consists of a main CPU 61, ROM 62, RAM 63, EEPROM 64, timer 65, main display unit 66, operation unit 67, communication I / F 68, laser scanner control unit 69, PWM control unit 70, A / D converter 76, and input port 79. These components are connected via a system bus. Furthermore, the PWM control unit 70 is connected to a heater control unit 71, a transport motor 72, a drum motor 73, a fuser motor 74, and a high-voltage generation unit 75. The A / D converter 76 is connected to a temperature sensor 77 and a humidity sensor 78. The input port 79 is connected to a paper feed transport sensor 80 and a paper discharge transport sensor 81.

[0043] The main CPU 61 comprehensively controls image processing and printing based on saved programs and other data.

[0044] ROM 62 and EEPROM 64 store programs and data necessary for the main CPU 61 to perform various processes, and RAM 63 operates as a work area. Timer 65 is used for various timing control by the main CPU 61. The main display unit 66 displays setting information of the image forming apparatus 100 and the processing status of print jobs. The operation unit 67 accepts input of various settings and operation instructions from the user. The communication interface 68 is connected to the static elimination device 200 via a communication cable, and communication for the control of each device takes place.

[0045] The laser scanner control unit 69 is a device that irradiates a photosensitive drum 1, which is charged to form an electrostatic latent image, with laser light modulated according to the image data. In the laser scanner control unit 69, the photosensitive drum 1 is charged to a uniform negative potential by the high-voltage generation unit 75 (described later), and the laser light is deflected by a polygon mirror while irradiating the photosensitive drum. As a result, the negative charge in the area of ​​the photosensitive drum 1 irradiated with laser light is neutralized, and an electrostatic latent image is formed.

[0046] The PWM control unit 70 controls the heater control unit 71, the transport motor 72, the drum motor 73, the fuser motor 74, and the high-pressure generation unit 75. The heater control unit 71 controls the temperature of the fuser device 30. The transport motor 72 drives the transport rollers for transporting the sheets and the pre-fusing transport device 31. The drum motor 73 rotates the photosensitive drum 1. The fuser motor 74 drives the fuser belt and other components of the fuser device 30. The A / D converter 76 performs A / D conversion, converting the analog signals output from the temperature sensor 77 and humidity sensor 78 into digital signals. The input port 79 receives the output signals from the paper feed sensor 80 and the paper discharge sensor 81.

[0047] Next, the configuration of the static elimination device 200 will be described. The static elimination device 200 consists of a static elimination CPU 82, ROM 83, RAM 84, EEPROM 85, timer 86, communication I / F 87, PWM control unit 88, output port 91, and input port 94. In this embodiment, the static elimination control unit 98 includes the static elimination CPU 82, ROM 83, RAM 84, EEPROM 85, and timer 86. These components are connected via a system bus. Furthermore, a static elimination roller motor 89 and a static elimination high-voltage control unit 90 are connected to the PWM control unit 88. An ionizer ON / OFF signal 92 and a maintenance detection mode transition signal 93 are output from the output port 91. Furthermore, a static elimination display unit 56 is connected to the output port 91, and data corresponding to the information to be displayed on the static elimination display unit 56 is output from the output port 91. A maintenance detection signal 95 is input to the input port 94, and a static elimination operation unit 54 is connected to it. The ionizer 52 receives the ionizer ON / OFF signal 92 and the maintenance detection mode transition signal 93 as inputs and outputs the maintenance detection signal 95.

[0048] The static elimination CPU 82 performs various controls necessary for static elimination and ejection of paper based on stored programs, etc. ROM 83 and EEPROM 85 store programs and data necessary for the static elimination CPU 82 to perform various processing. RAM 84 operates as a work area. Timer 86 controls various timings by the static elimination CPU 82 and measures the operating time of the ionizer 52. Communication I / F 87 is connected to the image forming apparatus 100 via a communication cable, and communication for the control of each device takes place.

[0049] The PWM control unit 88 controls the static elimination roller motor 89 and the static elimination high-voltage control unit 90 to eliminate static electricity and transport the paper discharged from the image forming apparatus 100. The output port 91 outputs an ionizer ON / OFF signal 92, a maintenance detection mode transition signal 93, and the ON / OFF status of the static elimination display unit 56. The input port 94 receives a maintenance detection signal 95 and the ON / OFF status of the static elimination operation unit 54.

[0050] The ionizer 52 switches between generating and stopping ions in response to the ionizer ON / OFF signal 92. When the ionizer ON / OFF signal 92 is at a high level, ions are generated; when it is at a low level, ions are stopped. The static elimination CPU 82 controls ion generation and ion stopping by switching the ionizer ON / OFF signal 92 at predetermined timings. When the ionizer ON / OFF signal 92 is at a high level, voltage is applied to the ionizer and ions are generated.

[0051] The maintenance detection mode transition signal 93 is a signal that switches the ionizer to a maintenance detection mode, which determines whether maintenance of the electrode section is necessary. The static elimination CPU 82 switches the maintenance detection mode transition signal 93 from L level to H level at a predetermined timing, thereby switching the ionizer 52 to maintenance detection mode. Note that the maintenance detection mode transition signal 93 switches from H level to L level 100ms after switching from L level to H level.

[0052] The maintenance detection signal 95 is a signal output when the ionizer determines that maintenance of the electrode section is required in the ionizer's maintenance detection mode. Specifically, the ionizer control unit 521 transitions to a maintenance detection mode, triggered by the switching of the maintenance detection mode transition signal 93 from an L level to an H level, in order to determine whether maintenance is required. The ionizer control unit 521 determines whether maintenance is required while in maintenance detection mode. The determination of whether maintenance is required by the ionizer control unit 521 is reflected in the maintenance detection signal 95. Specifically, if the maintenance detection signal 95 remains at an L level for a predetermined time, it indicates that maintenance is not required, and if it is at an H level, it indicates that maintenance is required. The ionizer control unit 521 continues to detect whether maintenance is required in maintenance detection mode until an H-level maintenance detection signal 95 is output or until a predetermined time has elapsed.

[0053] When the static elimination CPU 82 receives a high level output of the maintenance detection signal 95 from the ionizer control unit 521, the static elimination CPU 82 displays a maintenance warning on the main unit display unit 66 via the communication interface 87, recommending that the ionizer 52 be maintained. In the following explanation, the state where the maintenance detection signal 95 is at a high level corresponds to the state where the maintenance detection signal 95 has been output.

[0054] The ionizer 52 includes an ionizer control unit 521, an ion quantity detection sensor 522 for detecting the amount of ions, and an ion balance sensor 523 for detecting the balance between positive and negative ions. During maintenance detection mode, the ionizer control unit 521 uses the ion quantity detection sensor 522 and the ion balance sensor 523 to determine whether the ionizer can output with a normal amount of ions and ion balance.

[0055] <Ionizer maintenance detection and control> When the ionizer 52 detects a maintenance detection mode transition signal, the ionizer 52 performs maintenance requirement detection. Specifically, when the ionizer 52 detects the maintenance detection mode transition signal 93, the ionizer 52 starts operating, and the ion quantity detection sensor 522 detects the amount of ions generated per unit time. A predetermined voltage value is applied to the static elimination needle 520, and if the detected amount of ions generated is less than a predetermined amount, the ionizer control unit 521 outputs a maintenance detection signal 95.

[0056] If the detected amount of ions generated exceeds a predetermined amount, the positive or negative voltage applied to the static elimination needle 520 is gradually increased so that the ion balance detected by the ion balance sensor 523 falls within a predetermined range. In this embodiment, a positive voltage (high-voltage pulse of positive polarity) and a negative voltage (high-voltage pulse of negative polarity) are repeatedly applied alternately to the static elimination needle 520. That is, feedback control is performed to adjust the ion balance between positive and negative ions by increasing the amplitude of the positive voltage or the negative voltage. In other words, the positive or negative voltage is controlled so that the ion balance detected by the ion balance sensor 523 approaches 0. Here, an ion balance within a predetermined range means that the difference between the amount of positive and negative ions generated from one of the ionizers 52 in the upper unit 401 and the lower unit 402 is within a predetermined range.

[0057] If the ion balance does not fall within a predetermined range even when the ionizer 52 increases the voltage applied to the static elimination needle 520 to a predetermined upper limit, the ionizer control unit 521 outputs a maintenance detection signal 95. On the other hand, even if the ion balance falls within a predetermined range, the ionizer control unit 521 continues maintenance detection control for 30 seconds after detecting the maintenance detection mode transition signal 93. Maintenance detection control ends 30 seconds after the detection of the maintenance detection mode transition signal 93.

[0058] Specifically, the ionizer control unit 521 outputs a maintenance detection signal 95 when the amount of ions generated by the ionizer 52 is less than a predetermined amount, or when the ion balance is not within a predetermined range. In this embodiment, an ion amount detection sensor 522 and an ion balance sensor 523 are included, but the embodiment is not limited to these. The amount of ions generated and the ion balance may be calculated based on the positive and negative ion currents (return currents) that return to the ionizer circuit via earth.

[0059] In this embodiment, the ionizer detection process detects whether or not maintenance of the ionizer is required, but it is not limited to this. The ionizer detection process may also detect contamination of the ionizer or measure the performance of the ionizer.

[0060] <Screen display of the user control panel> Figure 8 shows the display contents of the main display unit 66 of the image forming apparatus 100. The main display unit 66 displays setting information of the image forming apparatus 100 and the processing status of print jobs. In this embodiment, the main display unit 66 is a touch panel, and in addition to displaying setting information and the processing status of print jobs, it also accepts input of various settings and operation instructions from the user.

[0061] The display screen includes an upper status area 501 located at the top of the screen, which displays the status of the image forming apparatus, and a lower status area 502 located at the bottom of the screen, which displays warnings for the image forming apparatus 100 and the static eliminator 200. Furthermore, the display screen includes a job setting area 504 between the upper status area 501 and the lower status area 502, where the user sets the job details. Above the job setting area 504 is a setting display area 503 that displays the settings for when a job is submitted to the image forming apparatus 100, as set by the user. The upper status area 501 mainly displays whether the print job is executable, whether the print job is in progress, or whether the print job is not executable.

[0062] Figure 8(a) shows the display screen of the main unit display unit 66 when the maintenance detection signal 95 is not output. Figure 8(b) shows the display screen of the main unit display unit 66 when the maintenance detection signal 95 is output. Specifically, the screen in Figure 8(a) does not display a message prompting the user to clean the ionizer 52. The screen in Figure 8(b) displays a message prompting the user to clean the ionizer 52. In this embodiment, even when a maintenance warning for the ionizer 52 is issued, the main unit CPU 61 can still accept jobs. Therefore, the screen in Figure 8(b) displays a message prompting the user to clean the ionizer 52 in the lower status area 502, and also displays in the upper status area 501 that it is possible to accept jobs.

[0063] In this embodiment, the main unit display unit 66 displays a message prompting the user to clean the ionizer 52, but the display content is not limited to this. The degree of contamination of the ionizer 52 may be displayed, or the static elimination performance of the ionizer 52 may be displayed.

[0064] Furthermore, as shown in the screen in Figure 8(b), if a maintenance detection signal 95 is output, a guidance key 663 capable of displaying guidance on the cleaning procedure is displayed in the lower status area 502. When the user presses the guidance key 663, the cleaning procedure guidance is displayed on the display screen. Specifically, the cleaning procedure can be explained using illustrations, messages, videos, etc., showing how the user can access the electrode part of the ionizer 52 and how to clean using each cleaning component. For example, as a way to access the electrode part of the ionizer, it may be shown that the upper unit 401 of the static eliminator 200 should be lifted upwards.

[0065] In this embodiment, the notification prompting the user to clean the ionizer is provided using the main display unit 66 of the image forming apparatus 100. However, the notification is not limited to this, and the notification prompting the user to clean the ionizer may also be provided using the static elimination display unit 56 of the static elimination device 200. For example, the notification may be provided by changing the display color, brightness, or blinking cycle of the LEDs on the static elimination display unit 56. For example, the static elimination display unit 56 may be used to notify the user with text or the like using a display. Alternatively, both the main display unit 66 and the static elimination display unit 56 may be used.

[0066] <Explanation of the flowchart> Incidentally, jobs cannot be executed while the ionizer's electrode section is undergoing maintenance. Therefore, if maintenance is required for the electrode section as a result of the maintenance detection process performed in the middle of a continuous job, the printing process must be interrupted, which presents a problem as it reduces the user's work efficiency.

[0067] In this embodiment, in addition to performing maintenance requirement detection when the cumulative operating time of the non-contact static elimination unit exceeds a first threshold, maintenance requirement detection is also performed when the image forming apparatus transitions from a first state to a second state with lower power consumption than the first state. This reduces the frequency of interruptions to the user's printing work and improves work efficiency.

[0068] Figure 9 is a flowchart of the control performed by the static elimination CPU 82 of the static elimination control unit 98.

[0069] The static elimination CPU 82 obtains sheet information from the main unit CPU 61 via the communication I / F 87 and determines whether or not a job has started (S1001). Before a job starts, the main unit display 66 of the image forming apparatus 100 displays that a print job is available, as shown in Figure 8(a). The job sheet information is data that includes information on whether it is the final sheet of the job, and is transmitted when the sheet is handed over from the image forming apparatus 100 to the static elimination device 200.

[0070] When a job is started (S1001-Y), the static elimination CPU 82 switches the ionizer ON / OFF signal 92 from L level to H level, and the ionizer 52 starts outputting (S1002). The static elimination CPU 82 instructs the timer 86 to start measuring the operating time of the ionizer 52 (S1003). The timer 86 starts measuring from 0 seconds.

[0071] When the image-formed sheet S passes through the ionizer 52, the static elimination CPU 82 determines whether the print job is finished (S1004). Specifically, it determines whether the last sheet of the print job has passed through. If the last sheet has passed (S1004-Y), the static elimination CPU 82 switches the ionizer ON / OFF signal 92 from H level to L level and stops the output of the ionizer 52 (S1005). Next, the static elimination CPU 82 terminates the measurement of the operating time of the ionizer 52 by the timer 86 (S1006).

[0072] The static elimination CPU 82 acquires the timer value T1 measured by the timer 86 (S1007). In this embodiment, the acquired timer value T1 is the operating time of the ionizer 52 in the job. In addition, the cumulative timer value T1, which is the operating time of the ionizer 52 for each job since the last maintenance requirement detection was performed, is stored in memory as the cumulative time Ts. The timer value T1 for the current job is added to the cumulative time Ts (S1008). The cumulative time Ts is stored in non-volatile memory.

[0073] Next, the static elimination CPU 82 calculates the cumulative time T. S It is determined whether the first threshold of 600 seconds has been exceeded (S1009). The static elimination CPU 82 determines the cumulative operating time T S If the time has not exceeded 600 seconds (S1009-N), the process proceeds to S1001. The static elimination CPU 82 calculates the cumulative time T S If the time exceeds 600 seconds (S1009-Y), the static elimination CPU 82 will calculate the cumulative time T. S Initialize to 0 (S1010). The static elimination CPU 82 switches the maintenance detection mode transition signal 93 from L level to H level, causing the ionizer 52 to start detecting whether maintenance is required (S1011).

[0074] When the static elimination CPU 82 receives a maintenance detection signal 95 from the ionizer 52 (S1012-Y), the static elimination CPU 82 notifies the main unit CPU 61 of a maintenance warning via the communication interface 87 (S1013), and the process proceeds to S1001. When the main unit CPU 61 receives a maintenance warning notification from the static elimination CPU 82, it displays a maintenance warning on the main unit display unit 66 recommending cleaning the ionizer (Figure 8(b)).

[0075] If the static elimination CPU 82 does not receive a maintenance detection signal 95 from the ionizer 52 (S1012-N) and 30 seconds have elapsed (S1014), the process proceeds to S1001. In other words, if the maintenance detection signal 95 remains at the L level for a predetermined time, it indicates that maintenance detection has been successfully performed for the predetermined time. At this time, cleaning of the ionizer 52 is not necessary, so the static elimination CPU 82 does not display a maintenance warning recommending cleaning the ionizer on the main unit display unit 66 (the screen shown in Figure 8(a) is displayed).

[0076] In this embodiment, the threshold for determining whether or not the ionizer needs cleaning is 30 seconds after the start of maintenance requirement detection is set. However, the threshold for determining whether or not the ionizer needs cleaning is not limited to this, and can be set as appropriate.

[0077] Furthermore, if a user submits a job while ionizer 52 is detecting whether maintenance is necessary, the maintenance detection process may be interrupted and the job may be prioritized. However, if maintenance detection is interrupted, the accumulated time Ts will not be cleared.

[0078] In the present embodiment, although the integrated time Ts, which is the operation time of the ionizer, is used to determine whether to perform maintenance requirement detection, it is not limited to this. For example, the determination may be made using the cumulative number of sheets passing through the static eliminator 200. In addition to the first threshold value compared with the integrated time Ts, which is the cumulative time since the previous maintenance requirement detection was performed, a third threshold value compared with the timer value T1, which is the operation time of the ionizer 52 in one job, may be provided. Then, when the integrated time Ts in a plurality of static elimination processes exceeds the first threshold value, the static elimination CPU 82 executes the maintenance requirement detection process. Further, even when the integrated time Ts is less than or equal to the first threshold value, if the timer value T1, which is the operation time of the ionizer 52 in one static elimination process, exceeds the third threshold value, the static elimination CPU 82 executes the maintenance requirement detection process. Thereby, even when a long job is repeatedly performed, the maintenance requirement detection can be executed at an appropriate timing.

[0079] When the job has not started (S1001-N), the static elimination CPU 82 determines whether the main switch is turned off (S1021). When the main switch is turned off (S1021-Y), the static elimination CPU 82 determines whether a cooling operation (cooling operation) for lowering the temperature in the image forming apparatus 100 is being executed (S1022). When the cooling operation is not being executed (S1022-N), the static elimination CPU 82 determines whether the image forming apparatus 100 is executing an automatic adjustment operation for adjusting the image quality (S1023). When the automatic adjustment operation is not being executed (S1023-N), the process ends.

[0080] When the image forming apparatus 100 is executing the cooling operation (S1022-Y), or when the image forming apparatus 100 is executing the automatic adjustment operation (S1023-Y), the static elimination CPU 82 determines whether the integrated time T S exceeds the second threshold value of 400 seconds (S1031). When the integrated time T S does not exceed the second threshold value of 400 seconds, the process ends (S1031-N). In other words, when the integrated time T SIf the second threshold of 400 seconds has not been exceeded, maintenance necessity detection will not be performed.

[0081] Total time T S If the second threshold of 400 seconds is exceeded (S1031-Y), the static elimination CPU 82 will perform the cumulative time T S The value is initialized to 0 (S1032). The static elimination CPU 82 switches the maintenance detection mode transition signal 93 from L level to H level, causing the ionizer 52 to start detecting whether maintenance is required (S1033).

[0082] If the static elimination CPU 82 receives a maintenance detection signal 95 from the ionizer 52 (S1034-Y), it saves the cleaning warning flag ON information as a backup value in the EEPROM 85 (S1035), and the process ends. If the static elimination CPU 82 does not receive a maintenance detection signal 95 from the ionizer 52 (S1034-N) and 30 seconds have elapsed (S1036-Y), the process ends. The image forming apparatus 100 is powered off after it has completed a cool-down operation or an automatic adjustment operation.

[0083] However, the determination of whether or not maintenance is required is not limited to this. The determination of whether cooldown is in progress (S1022), whether automatic adjustment operation is in progress (S1023), and whether the accumulated time is above the second threshold (S1031) may be omitted as appropriate.

[0084] Note that the static elimination control unit 98 and the ionizer control unit 521 are examples of control units. The static elimination process and the maintenance requirement detection process may be performed by either the static elimination control unit 98 or the ionizer control unit 521.

[0085] In this embodiment, maintenance requirement detection is performed when the main switch is turned off. The operation unit 67 is equipped with a main switch and accepts input of various settings and operation instructions from the user. The main switch is a switch that switches the power of the image forming apparatus on and off. Note that turning the power on is an example of the first state, and turning the power off is an example of the second state, which consumes less power than the first state. When the main switch is switched from on to off, the image forming apparatus 100 transitions from the first state to the second state. When the main switch is switched from off to on, the image forming apparatus 100 transitions from the second state to the first state.

[0086] In this embodiment, the first state is the state where the power is on, and the second state is the state where the power is off, but this is not limited to this. The first state is the normal state, and the second state, which consumes less power than the first state, may be the sleep state. The image forming apparatus transitions from the normal state to the sleep state when the power saving mode is selected as the priority, and there is no operation for a certain period of time after the job is completed. The power saving mode is selected as the priority when the power saving key provided on the operation unit 67 is pressed. The time from the completion of a job to the transition to the sleep state is set in advance, but can be changed by the operation unit 67.

[0087] As mentioned above, the image forming apparatus automatically enters sleep mode if there is no operation for a certain period of time, but this is not the only way. The image forming apparatus may also enter sleep mode when the power saving key is pressed. That is, if the power saving mode is selected by the user and the job is completed, the static elimination CPU 82 may perform maintenance detection on the ionizer 52. After that, when the image forming apparatus returns from sleep mode to normal mode, the static elimination CPU 82 displays the result of the maintenance detection on the main unit display 66. However, this is not limited to this, and the result of the maintenance detection may also be notified while the apparatus is in sleep mode.

[0088] In other words, the static elimination CPU 82 performs maintenance requirement detection processing between the time it receives an instruction to transition the image forming apparatus from the first state to the second state, which consumes less power than the first state, and the time the image forming apparatus actually transitions to the second state. To put it another way, based on the instruction to transition the image forming apparatus from the first state to the second state, which consumes less power than the first state, the static elimination CPU 82 performs maintenance requirement detection in the first state, and the image forming apparatus transitions to the second state after the maintenance requirement detection is completed.

[0089] One example of an instruction that causes the image forming apparatus to transition from the first state to the second state is to switch the power switch for the image forming apparatus from on to off. Another example is when the power saving key is pressed to put the apparatus into sleep mode. Yet another example is when the apparatus is set to automatically enter sleep mode, and no operation is performed after a set time has elapsed.

[0090] In this embodiment, the static elimination CPU 82 performs maintenance detection for the ionizer 52 when the main switch is turned off and the accumulated time Ts exceeds the second threshold of 400 seconds. However, the static elimination CPU 82 may perform maintenance detection every time the main switch is turned off, without setting a threshold. However, if maintenance detection is performed between the completion of the last job before the power off instruction and the instruction to turn off the power, maintenance detection does not need to be performed when the power is turned off.

[0091] Furthermore, in order to prevent deterioration of the ionizer 52, it is preferable to perform maintenance necessity detection as infrequently as possible. For this reason, as in this embodiment, it is preferable to set a threshold that is compared with the accumulated time to determine whether or not the static elimination CPU 82 will perform maintenance necessity detection when the power is turned off. Specifically, the second threshold, which is the criterion for performing maintenance necessity detection when the power is turned off, is smaller than the first threshold, which is the criterion for performing maintenance necessity detection after static elimination processing. In this embodiment, the first threshold is 600 seconds and the second threshold is 400 seconds. In other words, the second threshold is set to be less than or equal to two-thirds of the first threshold.

[0092] Figure 10 is a flowchart showing the actions performed by the static elimination CPU 82 when the power is turned on.

[0093] When the power to the image forming apparatus 100 is turned on, the static elimination CPU 82 reads a backup value from the EEPROM 85 and determines whether the value of the backup cleaning warning flag is ON (S1201). This determination is made, for example, based on the maintenance necessity detection result stored in the EEPROM 85 in S1035 of Figure 9. If the value of the backup cleaning warning flag is ON (S1201-Y), the static elimination CPU 82 notifies the main unit CPU 61 of a maintenance warning via the communication I / F 87 (S1202). When the main unit CPU 61 receives a maintenance warning notification from the static elimination CPU 82, it displays a warning on the main unit display unit 66 recommending cleaning the ionizer (Figure 8(b)). Next, the static elimination CPU 82 returns the backup cleaning warning flag to OFF (S1203) and waits until the job starts (S1204).

[0094] If the backup cleaning warning flag is OFF (S1201-N), the static elimination CPU 82 waits until the job starts (S1204). At this time, cleaning of the ionizer 52 is not necessary, so the static elimination CPU 82 does not display a maintenance warning recommending cleaning of the ionizer 52 on the main unit display unit 66 (Figure 8(a) is displayed).

[0095] In this embodiment, the results of the maintenance requirement detection performed when the power is turned off are displayed on the main unit display unit 66 when the power is turned on. However, the main unit display unit 66 may also be used when the static elimination CPU 82 receives a maintenance detection signal 95 from the ionizer 52 (S1034-Y), until the power is turned off. However, when the power is turned off, the user may not be near the main unit display unit 66. Therefore, it is preferable to display the results when the power is turned on in order to make it easier for the user to notice the results of the maintenance requirement detection.

[0096] The static elimination CPU 82 may perform maintenance necessity detection not only based on the power being turned off, but also based on the power being turned on for the image forming apparatus. However, if the static elimination CPU 82 has performed maintenance necessity detection when the power of the image forming apparatus is turned off, the user can understand the detection result and begin preparing for cleaning without waiting for the maintenance necessity detection to be completed when the power is turned on.

[0097] In other words, the control unit calculates the ionizer's cumulative time T. S In addition to performing maintenance requirement detection after job completion when the first threshold is exceeded, maintenance requirement detection is also performed when the image forming apparatus 100 transitions from the first state to the second state with lower power consumption. This reduces the frequency with which printing operations are interrupted because the user cannot execute the next job while cleaning the ionizer. Furthermore, the results of the maintenance requirement detection performed when the image forming apparatus 100 transitions from the first state to the second state are displayed on the main unit display unit 66 when transitioning from the second state to the first state. This allows the user to start printing operations only after the ionizer cleaning is complete.

[0098] In this embodiment, an ionizer 52 was used in the non-contact static elimination unit 58, but this is not limited to this, and a Corotron may also be used. Also, in this embodiment, the voltage value is set so that the surface potential of the sheet approaches 0 when a voltage is applied to the static elimination roller 50 as the contact static elimination unit 57, but this is not limited to this. The static elimination device 200 also functions as a charge adjustment device that adjusts the charged state of the sheet by supplying charge to the sheet via the static elimination roller 50 as a charge supply member. The charge adjustment device does not necessarily reduce the amount of charge on the sheet (does not eliminate static charge). For example, when the sheets are stacked after processing by the charge adjustment device, the amount of charge on each surface of the sheet may be adjusted so that the opposing surfaces of overlapping sheets are charged with the same polarity. Specifically, the charge adjustment device applies a voltage to every other sheet in a plurality of sheets so that the electrostatic polarity of the sheet surface is reversed. In other words, the voltage applied to the charge supply member is set to a magnitude that reverses the electrostatic polarity of the sheet surface, and the voltage is applied to every other sheet. In this case, the opposing surfaces of the overlapping sheets are charged with the same polarity, which reduces the adhesion between the sheets due to electrostatic force.

[0099] However, since the sheets have a large charge after being processed by the charge adjustment device described above, they are prone to sticking to the transport path, which may cause transport failures. To reduce sheet transport failures, a non-contact static elimination unit 58 may be placed downstream of the roller that adjusts the charge of the sheet in the charge adjustment device, and the sheet may be statically eliminated by the non-contact static elimination unit 58. In this case as well, by performing maintenance detection on the non-contact static elimination unit when transitioning the image forming apparatus from the first state to the second state, which consumes less power than the first state, the frequency of interruptions to the user's printing work can be reduced, and the user's work efficiency can be improved.

[0100] In the above-described embodiment, the image forming system was explained in the case where it was applied to an electrophotographic image forming system 300, but it is not limited to this, and may also be applied to an inkjet recording system. [Explanation of symbols]

[0101] 52 Ionizer 58 Non-contact static elimination unit 66 Main unit display 98 Static Elimination Control Unit 200 Static eliminator

Claims

1. An antistatic device connected to an image forming apparatus equipped with an image forming unit that forms an image on a sheet, A non-contact static elimination unit is provided, which includes an electrode unit that generates ions and removes static electricity from the sheet in which an image has been formed by the image forming unit, in a non-contact manner. A control unit that performs a detection process to determine whether or not maintenance of the electrode section is required, It has, The control unit executes the detection process from the time it receives an instruction to transition the image forming apparatus from the first state to a second state which consumes less power than the first state, until the image forming apparatus transitions to the second state. A static elimination device characterized by the following features.

2. It has a display unit that displays the results of the detection process, The display unit, when it is determined by the detection process that maintenance of the electrode unit is necessary, displays content indicating that maintenance of the electrode unit is necessary. The static elimination device according to feature 1.

3. If the detection process determines that maintenance of the electrode section is necessary, the display unit will display content indicating that maintenance of the electrode section is necessary when the image forming apparatus transitions from the second state to the first state. The static elimination device according to feature 2.

4. It has a switch that toggles between ON, which transitions from the second state to the first state, and OFF, which transitions from the first state to the second state. The control unit executes the detection process based on the fact that the switch changes from on to off. The static elimination device according to feature 1.

5. The second state is a sleep state, and has a key to select prioritizing the second state. The control unit executes the detection process based on the fact that the key has been pressed. The static elimination device according to feature 1.

6. The control unit executes the detection process based on the fact that the second state is selected to take precedence by the key, and that there has been no user operation for a certain period of time since the job was completed. The static elimination device according to feature 5.

7. If the detection process is executed after the last executed job has finished, before transitioning from the first state to the second state, the control unit will... The detection process is not performed between the instruction to transition the image forming apparatus from the first state to the second state and the time the image forming apparatus transitions to the second state. The static elimination device according to feature 1.

8. The control unit performs a job in which the image forming unit forms an image on the sheet and the non-contact static elimination unit removes static electricity from the sheet, and a detection process for detecting whether or not maintenance of the electrode unit is required. If the cumulative operating time of the non-contact static elimination unit in the job exceeds a first threshold, the control unit executes the detection process after the job is completed. Even if the cumulative operating time does not exceed the first threshold, if the cumulative operating time exceeds a second threshold which is smaller than the first threshold when the image forming apparatus is instructed to transition from the first state to the second state, the detection process is executed. The static elimination device according to feature 1.

9. The second threshold is less than or equal to two-thirds of the first threshold. The static elimination device according to feature 8.

10. The control unit, when the image forming apparatus transitions from the first state to the second state, The detection process is executed based on a cooling operation to lower the temperature of the image forming apparatus, or an adjustment operation to adjust the conditions for image formation. The static elimination device according to feature 1.

11. The control unit performs a job in which the image forming unit forms an image on the sheet and the non-contact static elimination unit removes static electricity from the sheet, and a detection process for detecting whether or not maintenance of the electrode unit is required. The control unit executes the detection process after the job is completed if the cumulative number of sheets that have passed through the non-contact static elimination unit in the job exceeds a first threshold. Even if the cumulative number of images does not exceed the first threshold, if the cumulative number of images exceeds a second threshold which is smaller than the first threshold, when the image forming apparatus is instructed to transition from the first state to the second state, the detection process is executed. The static elimination device according to feature 1.

12. The static elimination device according to claim 1, An image forming system comprising the aforementioned image forming apparatus.

13. An image forming unit that forms an image on a sheet, A non-contact static elimination unit is provided, which includes an electrode unit that generates ions and removes static electricity from the sheet in which an image has been formed by the image forming unit, in a non-contact manner. A control unit that performs a detection process to determine whether or not maintenance of the electrode section is required, An image forming system having, The control unit executes the detection process from the time it receives an instruction to transition the image forming system from a first state to a second state which consumes less power than the first state, until the image forming system transitions to the second state. An image forming system characterized by the following features.

Images