Static elimination device and image forming system

Abstract

There was a risk that the detection process for determining whether or not maintenance of the non-contact static elimination unit was required might be unintentionally interrupted. [Solution] A static elimination device characterized by comprising: an electrode section for generating ions; a non-contact static elimination section for eliminating static electricity from a sheet in a non-contact manner for eliminating static electricity from a sheet for which an image has been formed in an image forming section; a control section that performs a detection process to detect whether or not maintenance of the electrode section is required; and a display section that displays an indication that the detection process is being performed.

Description

Technical Field

[0001] The present invention relates to a static eliminator and an image forming system.

Background Art

[0002] In an image forming apparatus that forms an image on a sheet, when forming an image on the sheet, the sheet may be charged, and the discharged sheets may stick to each other, resulting in poor stacking. Therefore, an image forming system provided with a non-contact static eliminator that statically eliminates the sheet in a non-contact state has been proposed.

[0003] When the non-contact static eliminator is continuously used, dust and organic substances in the air may deposit on the electrode portion of the non-contact static eliminator, resulting in a decrease in the static elimination performance of the non-contact static eliminator. Therefore, it is desirable that the non-contact static eliminator be maintained at an appropriate timing. In Citation 1, when the number of sheets statically eliminated by the non-contact static eliminator reaches a threshold value, a detection process for detecting whether maintenance of the electrode portion of the non-contact static eliminator is necessary is executed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, depending on the user's operation, the detection process for detecting whether maintenance of the non-contact static eliminator is necessary may be unintentionally interrupted. In such a case, since the detection of the necessity of maintenance of the non-contact static eliminator is not performed, there is a risk that the static elimination performance may deteriorate and the sheets may stick to each other. Therefore, an object of the present invention is to provide a static eliminator and an image forming system that reduce the possibility of unintentional interruption of the detection process for detecting whether maintenance of the non-contact static eliminator is necessary. [Means for solving the problem]

[0006] One embodiment of the present invention is a static elimination device characterized by comprising: an electrode section for generating ions; a non-contact static elimination section for eliminating static electricity from a sheet in a non-contact manner for eliminating static electricity from a sheet imaged by an image forming section; a control section that performs a detection process to detect whether or not maintenance of the electrode section is required; and a display section that displays an indication that the detection process is being performed. [Effects of the Invention]

[0007] In this invention, it is possible to reduce the possibility that the detection process for determining whether or not maintenance of the non-contact static elimination unit is required may be unintentionally interrupted. [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 operation section in Example 1. [Figure 9] Control flowchart of the static elimination control unit in Example 1. [Figure 10] Control flowchart for the maintenance requirement detection operation in Example 1. [Figure 11] Control flowchart of the static elimination control unit in Example 2. [Figure 12] Control flowchart of the image forming apparatus in Example 3. [Figure 13] Control flowchart of the static elimination control unit in Example 3. [Figure 14] Control flowchart for the maintenance requirement detection operation in Example 3. [Figure 15] Screen display of the user operation section in Example 3. [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 that is 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 to form toner images on the surfaces of the respective photosensitive drums 1Y, 1M, 1C, and 1K. In the present 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 so as to contact 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 that controls 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 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 surface reading sensor 17 is provided. The belt surface reading sensor 17 reads the image transferred onto the intermediate transfer belt 6. The belt surface 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 surface 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 surface 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 eliminates static charge from the sheet while in contact with the sheet. Next, the non-contact static elimination unit 58 removes any remaining charge that could not be eliminated by the contact static elimination unit 57, and the sheet S 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. The housing 59 houses the contact static elimination unit 57, the non-contact static elimination unit 58, and the transport guide 53, and the static elimination indicator unit 56 is located on the exterior surface of the housing 59. The static elimination indicator unit 56 may also be provided 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 that faces the front of the device, and the front surface 200b includes inclined surfaces that are inclined to intersect with the vertical direction. By placing 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 casing, or it may be connected to the device by a cable and placed on top of the device. Alternatively, the static elimination indicator unit 56 may not be connected to the main body of the device by a cable, and wireless communication may be performed via Bluetooth. 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 the H level, ions are generated; when it is at the L 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.

[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 maintenance detection 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> Incidentally, with conventional devices, the maintenance necessity detection process, which determines whether or not maintenance is required, could be interrupted by careless user actions. Specifically, users could interrupt the maintenance necessity detection process by turning off the device's power or submitting a new job in the middle of it. Furthermore, because the timing of the maintenance necessity detection operation depended on the job submission status, such as the length and frequency of jobs, users (operators) could not know when the maintenance necessity detection was running.

[0061] 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.

[0062] The display screen includes a status area 501 located at the top of the screen that displays the status of the image forming apparatus, and a warning area 502 located at the bottom of the screen that displays warnings from the image forming apparatus 100 and the static eliminator 200. Furthermore, the display screen includes a job setting area 504 between the status area 501 and the warning area 502 where the user can set the job details. Additionally, the display screen includes a setting display area 503 between the status area 501 and the job setting area 504 that displays the settings set by the user when submitting a job to the image forming apparatus 100. The status area 501 displays, for example, whether the print job is executable, whether the print job is currently running, or whether the print job is not executable for some reason.

[0063] Figure 8(a) shows the display screen when the image forming apparatus 100 is able to execute a print job. Figure 8(b) shows the display screen during maintenance requirement detection operation. Figure 8(c) shows the display screen that warns of the maintenance requirement detection operation. Figure 8(d) shows the display screen that notifies the result of the maintenance requirement detection operation.

[0064] 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(d) shows the display screen of the main unit display unit 66 when the maintenance detection signal 95 is output. Figure 8(b) shows the display screen of the main unit display unit 66 when maintenance necessity detection is being performed. Figure 8(c) shows the display screen of the main unit display unit 66 before maintenance necessity detection is performed, when the conditions for performing maintenance necessity detection are met.

[0065] In this embodiment, the main CPU 61 can accept jobs even when the maintenance requirement detection operation is in progress. Therefore, the screen in Figure 8(b) displays a message in the warning area 502 indicating that the system is checking whether maintenance of the ionizer is required, and the status area 501 indicates that the system can accept jobs.

[0066] Furthermore, even before the maintenance check operation is performed, the main CPU 61 can accept jobs. Therefore, the screen in Figure 8(c) displays a message in the warning area 502 notifying the user to check whether ionizer maintenance is required after the job, and the status area 501 indicates that jobs can be accepted. When displaying Figures 8(b) and 8(c), it is also possible to add a message recommending that the power to the image forming apparatus 100 and the static eliminator 102 not be turned off, and that print jobs should not be submitted.

[0067] Even if a maintenance warning for the ionizer 52 is issued as a result of the maintenance requirement check, the main unit CPU 61 can still accept jobs. Therefore, the screen in Figure 8(d) displays a message prompting the user to clean the ionizer in the warning area 502, and indicates in the status area 501 that the system can accept jobs. Furthermore, a guidance key 663 is displayed in the warning area 502, which can display guidance on the cleaning procedure. When the user presses the guidance key 663, the cleaning procedure guidance is displayed on the 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, the system may display instructions to lift the upper unit 401 of the static eliminator 200 upwards.

[0068] 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.

[0069] <Operation of the static elimination control unit in Example 1> Figure 9 is a flowchart of the control performed by the static elimination CPU 82 of the static elimination control unit 98 in Embodiment 1. Before the job is started, the main display unit 66 of the image forming apparatus 100 displays that a print job is available, as shown in Figure 8(a). When the job is started, processing by the static elimination CPU 82 begins via the communication I / F 87.

[0070] The static elimination CPU 82 switches the ionizer ON / OFF signal 92 from L level to H level, and starts the output of the ionizer 52 (S501). The static elimination CPU 82 causes the timer 86 to start measuring the operating time of the ionizer 52 (S502). The timer 86 starts measuring time from 0 seconds. The CPU then waits until it receives job sheet information from the image forming apparatus 100 via the communication I / F 87 (S503-N). The job sheet information is data that includes information on whether it is the final sheet of the job, and is transmitted at the timing when the sheet is handed over from the image forming apparatus 100 to the static elimination device 200.

[0071] When the static elimination CPU 82 receives job sheet information from the image forming apparatus 100 via the communication I / F 87 (S503-Y), it determines whether the rear end of the sheet has been removed from the static elimination device 200 (S504). Specifically, the static elimination CPU 82 determines whether the rear end of the sheet has been removed based on the time elapsed since the sheet information was received. When the static elimination CPU 82 determines that the rear end of the sheet has been removed from the static elimination device 200 (S504-Y), it obtains the elapsed time T1 of the timer 86 (S505) and resets the timer 86 (S506). After resetting the timer 86, it starts measuring time again from 0 seconds. In addition, the cumulative elapsed time T1 of the ionizer 52 since the last maintenance requirement detection is stored in memory as the accumulated time Ts. The static elimination CPU 82 updates the accumulated time Ts by adding the elapsed time T1 measured by the timer 86 to the accumulated time Ts (S507). The accumulated time Ts is stored in non-volatile memory.

[0072] Next, the static elimination CPU 82 determines whether the accumulated time Ts exceeds 600 seconds (S508). If the accumulated time Ts exceeds 600 seconds (S508-Y), the static elimination CPU 82 turns on the maintenance requirement detection execution flag in RAM 84 (S509). If the accumulated time Ts does not exceed 600 seconds (S508-N), the process proceeds to S510. Next, the static elimination CPU 82 determines in S504 whether the sheet that has left the static elimination device 200 is the last sheet (S510). If it is not the last sheet (S510-N), the process returns to receiving sheet information (S503). If it is the last sheet (S510-Y), the static elimination CPU 82 switches the ionizer ON / OFF signal 92 from H level to L level, stops the output of the ionizer 52 (S511), and stops the timer 86 (S512).

[0073] Next, the static elimination CPU 82 determines whether the maintenance necessity detection execution flag held in RAM 84 is ON (S513). If the maintenance necessity detection execution flag is OFF (S513-N), the static elimination CPU 82 terminates processing. If the maintenance necessity detection execution flag is ON (S513-Y), the static elimination CPU 82 performs maintenance necessity detection (S514) and terminates processing. The static elimination CPU 82 turns the maintenance necessity detection flag OFF immediately before performing maintenance necessity detection. However, the timing of turning the maintenance necessity detection flag OFF is not limited to this. For example, the maintenance necessity detection flag may be turned OFF at the timing of clearing the accumulated time Ts, which will be described later.

[0074] However, the static elimination process, in which the multiple sheets transported from the image forming unit are ionized by the ionizer, may be performed by either the ionizer control unit 521 or the static elimination control unit 98. Also, the detection process for determining whether or not maintenance of the ionizer is required may be performed by either the ionizer control unit 521 or the static elimination control unit 98. In this embodiment, the static elimination control unit 98 and the ionizer control unit 521 are examples of control units.

[0075] In this embodiment, the cumulative time Ts of the ionizer and the first threshold Tslimit are compared to determine whether or not to perform maintenance detection. In this embodiment, 600 seconds is an example of the first threshold Tslimit. The first threshold Tslimit can be set as appropriate. In this embodiment, the cumulative time Ts is an example of the cumulative operating time of the ionizer 52.

[0076] Furthermore, the method for determining whether or not to perform maintenance necessity detection is not limited to this. For example, in addition to a first threshold Tslimit which is compared with the cumulative time Ts, which is the cumulative time since the last maintenance necessity detection was performed, a second threshold T2limit which is compared with the operating time T2 of the ionizer 52 in a single job may be provided.

[0077] In other words, the static elimination CPU 82 executes maintenance requirement detection processing when the cumulative time Ts, which is the sum of the operating time T2 of the ionizer 52 in multiple static elimination processes, exceeds a first threshold. Furthermore, even if the cumulative time Ts does not exceed the first threshold, the static elimination CPU 82 also executes maintenance requirement detection processing when the operating time T2 of the ionizer 52 in a single static elimination process exceeds a second threshold. This ensures that maintenance requirement detection is performed at the appropriate timing, even when long-running jobs are repeated. In addition, maintenance requirement detection may be performed when the power is turned off.

[0078] Furthermore, while the operating time of the ionizer is used to determine whether or not to perform maintenance detection, the determination is not limited to this; the number of sheets passing through the static elimination device 200 may also be used.

[0079] <Operation of maintenance requirement detection in Example 1> Figure 10 is a flowchart showing the maintenance requirement detection process in Example 1. The flowchart in Figure 10 provides a detailed explanation of the maintenance requirement detection process in S514 of Figure 9.

[0080] 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 (S601). The static elimination CPU 82 notifies the main CPU 61 of the image forming apparatus 100 via the communication I / F 87 to display a message indicating that maintenance is required on the main display unit 66 (S602). At this time, as shown in Figure 8(b), the main display unit 66 of the image forming apparatus 100 displays that the detection of whether maintenance of the ionizer 52 is required is in progress.

[0081] When the static elimination CPU 82 receives a maintenance detection signal 95 from the ionizer 52 (S603-Y), the static elimination CPU 82 instructs the main unit CPU 61 via the communication I / F 87 to hide the maintenance requirement detection operation message on the main unit display unit 66. The static elimination CPU 82 clears the accumulated time Ts (S605). The static elimination CPU 82 notifies the main unit CPU 61 of the maintenance requirement detection warning (S606) and terminates the process. If 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 8d).

[0082] If the static elimination CPU 82 has not received a maintenance detection signal 95 from the ionizer 52 (S603-N), the static elimination CPU 82 determines whether 30 seconds have elapsed since the start of maintenance necessity detection (S607). If 30 seconds have not elapsed since the start of maintenance necessity detection (S607-N), the process returns to S603. If 30 seconds have elapsed since the start of maintenance necessity detection without receiving a maintenance detection signal 95 (S607-Y), the static elimination CPU 82 hides the maintenance necessity detection operation message on the main unit display unit 66 via the communication I / F 87 (S608). Furthermore, the static elimination CPU 82 clears the accumulated time Ts (S609) and terminates the process. 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, since cleaning of the ionizer 52 is not necessary, the static elimination CPU 82 does not display a maintenance warning recommending cleaning the ionizer on the main unit display unit 66, and the screen shown in Figure 8(a) is displayed.

[0083] Furthermore, the maintenance requirement detection may be performed during the static elimination process in which the non-contact static elimination unit eliminates static electricity from the sheet while it is not in contact with the sheet. In this embodiment, the output of the ionizer 52 changes during the maintenance requirement detection process. Therefore, the static elimination process and the maintenance requirement detection process are not performed simultaneously; the maintenance requirement detection is performed after the static elimination process.

[0084] In this way, by notifying the user that maintenance necessity detection is in operation via the main unit display unit 66 or the static elimination display unit 56 while maintenance necessity detection is being performed, the user can understand the operating status of maintenance necessity detection. Therefore, the possibility of the user unintentionally interrupting maintenance necessity detection can be reduced.

[0085] (Example 2) In Example 1, the main unit display unit 66 notifies that maintenance requirement detection is in progress. In Example 2, in addition to notifying the main unit display unit 66 that maintenance requirement detection is in progress, the main unit display unit 66 is also notified of the operation of maintenance requirement detection. In Example 2, the explanation of the same configuration and processing as in Example 1 will be omitted, and only the differences from Example 1 will be explained.

[0086] <Operation of the static elimination control unit in Example 2> Figure 11 is a flowchart of the control performed by the static elimination CPU 82 of the static elimination control unit 98 in Embodiment 2. The processes from S701 to S709 in Figure 11 are the same as the processes from S501 to S509 in Figure 9, so their explanation is omitted.

[0087] If the accumulated time Ts exceeds 600 seconds (S708-Y), the static elimination CPU 82 turns on the maintenance requirement detection flag in RAM 84 (S709). The static elimination CPU 82 then notifies the main CPU 61 of the image forming apparatus 100 via the communication I / F 87 to display a message on the main display unit 66 informing it of the maintenance requirement detection operation (S710). At this time, as shown in Figure 8(c), the main display unit 66 of the image forming apparatus 100 displays a message indicating that it is about to perform an operation to detect whether or not maintenance of the ionizer 52 is required.

[0088] Next, the static elimination CPU 82 determines whether the sheet that has passed through the static elimination device 200 in S704 is the last sheet (S711). If it is not the last sheet (S711-N), the process returns to S703. If it is the last sheet (S711-Y), the static elimination CPU 82 switches the ionizer ON / OFF signal 92 from H level to L level, stops the output of the ionizer 52 (S712), and stops the timer 86 (S713).

[0089] Next, the static elimination CPU 82 determines whether the maintenance requirement detection execution flag held in RAM 84 is ON (S714). If the maintenance requirement detection execution flag is OFF (S714-N), the static elimination CPU 82 terminates processing. If the maintenance requirement detection execution flag is ON (S714-Y), the static elimination CPU 82 instructs the main unit CPU 61 via the communication I / F 87 to hide the message on the main unit display unit 66 that warns of the maintenance requirement detection operation (S715). Furthermore, the static elimination CPU 82 executes the maintenance requirement detection (S716) and terminates processing. Note that the static elimination CPU 82 turns the maintenance requirement detection flag OFF immediately before executing the maintenance requirement detection.

[0090] The operation of the maintenance requirement detection is the same as in Example 1, so it will be omitted.

[0091] In this embodiment, when the maintenance requirement detection execution flag is turned ON, the static elimination CPU 82 and the main unit display unit 66 display a message informing the user of the maintenance requirement detection operation. In other words, if it is decided in the middle of a job that maintenance requirement detection should be performed, the main unit display unit 66 displays the maintenance requirement detection operation informing message while the job is running. However, this is not limited to this, and when the maintenance requirement detection execution flag is turned ON, the main unit display unit 66 may display a message informing the user of the maintenance requirement detection operation a predetermined time before the job ends. Also, when the maintenance requirement detection execution flag is turned ON, the main unit display unit 66 may display a message informing the user of the maintenance requirement detection operation a predetermined number of times before the job ends. That is, the message informing the user of the maintenance requirement detection operation by the main unit display unit 66 only needs to be displayed from the time the maintenance requirement detection execution flag is turned ON until the maintenance requirement detection starts.

[0092] In this way, when the static elimination CPU 82 determines that it is necessary to perform maintenance detection, it displays a message on the main unit display unit 66 to announce the maintenance detection operation. Therefore, the user can know in advance that maintenance detection will be performed after a print job, and can appropriately adjust the timing of submitting the next print job.

[0093] (Example 3) In Example 3, when a user submits a job during the maintenance requirement detection operation notification or while the maintenance requirement detection is in operation, the maintenance requirement detection operation is interrupted, and the main unit display unit 66 displays a message to the user confirming whether to execute the job. In Example 3, the same configurations and processes as in Example 1 and Example 2 are omitted, and only the differences are explained.

[0094] Figure 15 shows the screen of the main unit display unit 66 when a job is submitted by the user during the maintenance necessity detection operation notification or while the maintenance necessity detection operation is in progress. A job confirmation message is displayed on the main unit display unit 66 so as to overlap at least part of the job setting area 504. Specifically, the main unit display unit 66 displays a message asking whether to skip the maintenance necessity detection operation and execute the job. Furthermore, the display unit 66 displays an accept button 664 that allows the user to select to skip the maintenance necessity detection operation and execute the submitted job.

[0095] When the user presses the Accept button 664, the execution confirmation message is hidden, and the maintenance necessity detection operation is skipped or interrupted. If the user does not press the Accept button 664, the maintenance necessity detection is executed or continues. If the maintenance necessity detection is completed without the Accept button 664 being pressed, the main unit display 66 hides the execution confirmation message and the Accept button 664 shown in Figure 15.

[0096] However, the main unit display unit 66 may also display a reject button 665 in addition to the accept button 664. Note that the accept button 664 displays "Yes" and the reject button 665 displays "No". If the user presses the reject button 665, the main unit CPU 61 hides the message shown in Figure 15 and the accept button 664 and reject button 665 on the main unit display unit 66 without waiting for the maintenance necessity detection to be completed. Furthermore, the static elimination CPU 82 causes the ionizer to perform or continue the maintenance necessity detection.

[0097] <Operation of the static elimination control unit in Example 3> Figure 13 is a flowchart of the control performed by the static elimination CPU 82 of the static elimination control unit 98 in Embodiment 3. The processes from S901 to S914 in Figure 13 are the same as the processes from S701 to S714 in Figure 11 of Embodiment 2, so their explanation is omitted.

[0098] The static elimination CPU 82 determines whether the maintenance requirement detection execution flag held in RAM 84 is ON (S914). If the maintenance requirement detection execution flag is OFF (S914-N), the static elimination CPU 82 terminates processing. If the maintenance requirement detection flag is ON (S914-Y), it determines whether or not it has received job submission information, which includes information on whether the next job has been submitted (S915). The job submission information is data that is sent from the image forming apparatus 100 to the static elimination device 200 via the communication I / F 87 when the image forming apparatus 100 receives a job based on the flowchart in Figure 12, which will be described later.

[0099] If the system has received information about the submission of the next job (S915-Y), the static elimination CPU 82 terminates control without performing maintenance necessity detection. In other words, if the user submits the next job while the main unit display 66 is announcing the operation of maintenance necessity detection, and presses "Yes" in the job execution confirmation message on the main unit display 66, the maintenance necessity detection operation will not be performed. In other words, if maintenance necessity detection is skipped, the accumulated time Ts will not be cleared.

[0100] If information for the next job has not been received (S915-N), the static elimination CPU 82, via the communication interface 87, hides the message indicating the maintenance requirement detection operation displayed on the main unit display unit 66 of the main unit CPU 61 (S916). Furthermore, the static elimination CPU 82 performs the maintenance requirement detection (S917) and terminates processing. Note that the static elimination CPU 82 turns OFF the maintenance requirement detection flag immediately before performing the maintenance requirement detection.

[0101] <Operation of maintenance requirement detection in Example 3> Figure 14 is a flowchart showing the maintenance requirement detection process in Example 3. The flowchart in Figure 14 provides a detailed explanation of the maintenance requirement detection process for S917 in Figure 13.

[0102] The processes S1001 to S1007 in Figure 14 are the same as the processes S601 to S607 in Figure 10 of Example 1, so their explanation is omitted.

[0103] If the static elimination CPU 82 has not received a maintenance detection signal 95 from the ionizer 52 (S1003-N), the static elimination CPU 82 determines whether 30 seconds have elapsed since it started the maintenance requirement detection (S1007). If 30 seconds have elapsed since the start of maintenance requirement detection without receiving the maintenance detection signal 95 (S1007-Y), the static elimination CPU 82 hides the "maintenance requirement detection in operation" message on the main unit display unit 66 via the communication I / F 87 (S1008). Furthermore, the static elimination CPU 82 clears the accumulated time Ts (S1009) and terminates the process. 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 displays the screen shown in Figure 8(a) on the main unit display unit 66 without displaying a maintenance warning recommending cleaning the ionizer.

[0104] If 30 seconds have not elapsed since the start of maintenance requirement detection (S1007-N), it is determined whether or not job submission information, which includes information on whether the next job has been submitted, has been received (S1010). Job submission information is data transmitted from the image forming apparatus 100 to the static elimination device 200 via the communication I / F 87 when the image forming apparatus 100 receives a job based on the flowchart in Figure 12, which will be described later.

[0105] If information for the next job has not been received (S1010-N), the process returns to S1003.

[0106] If the static elimination CPU 82 receives information about the submission of the next job (S1010-Y), it hides the message indicating that maintenance needs detection is in operation on the main unit display unit 66 via the communication interface 87 (S1011) and terminates processing. In other words, if the user submits the next job while the main unit display unit 66 is displaying the message indicating that maintenance needs detection is in operation, and the user presses "Yes" on the job execution confirmation message on the main unit display unit 66, the maintenance needs detection operation is interrupted. Note that if the static elimination CPU 82 receives information about the submission of the next job and interrupts maintenance needs detection (S1010-Y), the accumulated time Ts is not cleared. Therefore, since the accumulated time Ts exceeds the threshold during the next job, the maintenance needs detection execution flag remains ON during the next job as well.

[0107] <Operation of the image forming apparatus in Example 3> Figure 12 is a flowchart of the control performed by the main CPU 61 of the image forming apparatus 100.

[0108] The main CPU 61 waits until the job start button 666 (Figure 8) on the main display unit 66 is pressed (S801-N). At this time, the main display unit 66 of the image forming apparatus 100 displays, as shown in Figure 8, that a print job is available for execution or reservation.

[0109] When the user presses the job start button 666 on the main unit display unit 66 (S801-Y), the main unit CPU 61 determines whether the maintenance requirement detection operation is being announced or is currently in progress (S802). Whether the maintenance requirement detection operation is being announced is determined by whether the display unit 66 displays a message announcing the maintenance requirement detection operation (Figure 8(c)). Whether the maintenance requirement detection operation is currently in progress is determined by whether the display unit 66 displays a message indicating that the maintenance requirement detection operation is in progress (Figure 8(b)).

[0110] If the maintenance requirement detection operation is neither being announced nor in operation (S802-N), the main unit CPU 61 sends the next job submission information to the CPU 82 of the static eliminator 200 via the communication I / F 87 (S807), and terminates processing. After sending the next job submission information to the CPU 82 of the static eliminator 200 (S807), the main unit CPU 61 executes the submitted job.

[0111] If the maintenance requirement detection operation is being announced or is in progress (S802-Y), the main unit CPU 61 displays a job execution confirmation message (Figure 15) on the main unit display unit 66 (S803). The job execution confirmation message indicates that the ionizer maintenance requirement detection will be skipped and the submitted job will be executed. Furthermore, the job execution confirmation message displays an accept button 664 for the user to acknowledge the contents.

[0112] Next, the main CPU 61 determines whether or not job priority has been selected (S804). Specifically, it determines whether or not the accept button 664 has been pressed. If the accept button 664, which displays "Yes" in the job execution message shown in Figure 15, is pressed, the main CPU 61 determines that job priority has been selected. If the accept button 664, which displays "Yes," is not pressed, the main CPU 61 determines that job priority has not been selected.

[0113] If the user selects job priority (S804-Y), the main unit CPU 61 hides the job execution confirmation message displayed on the main unit display unit 66 (S806). Then, the main unit CPU 61 sends the next job submission information to the CPU 82 of the static eliminator 200 via the communication I / F 87 (S807), and terminates processing. After sending the next job submission information to the CPU 82 of the static eliminator 200 (S807), the main unit CPU 61 executes the submitted jobs as appropriate. Specifically, if a job is currently running, the next submitted job will start after the currently running job has finished.

[0114] If the user does not select job priority (S804-N), the main unit CPU 61 determines whether the maintenance requirement detection operation is being announced or is currently running (S805). If the maintenance requirement detection operation is being announced or is currently running (S805-Y), the process returns to S804. On the other hand, if the maintenance requirement detection operation is not being announced or is not currently running (S805-N), the main unit CPU 61 hides the job execution confirmation message displayed on the main unit display unit 66 (S806). Then, the main unit CPU 61 transmits the next job submission information to the static elimination CPU 82 of the static elimination device 200 via the communication I / F 87 (S807), and terminates processing. After transmitting the next job submission information to the static elimination CPU 82 of the static elimination device 200 (S807), the main unit CPU 61 executes the submitted job. In other words, the job execution confirmation message will be displayed and the job submission will be postponed until the maintenance requirement detection process is completed or until "Yes" is pressed on the job execution confirmation message shown in Figure 14.

[0115] In other words, the main CPU 61 displays a job execution confirmation message on the main display unit 66, and if the user selects job priority, it sends the next job submission information to the static elimination CPU 82, skipping the ionizer maintenance requirement detection. On the other hand, if the user does not select job priority after the main CPU 61 displays a job execution confirmation message on the main display unit 66, it waits until the ionizer maintenance requirement detection is completed.

[0116] Furthermore, the main unit display unit 66 may display different messages in the job execution confirmation message depending on whether the maintenance necessity detection operation is being announced or is currently underway. For example, the job execution confirmation message during the announcement of the maintenance necessity detection operation may include a message indicating that the maintenance necessity detection will be skipped, while the job execution confirmation message during the maintenance necessity detection operation may include a message indicating that the maintenance necessity detection will be interrupted. This allows the user to be notified in the job confirmation message during the maintenance necessity detection operation that the maintenance necessity detection has already started.

[0117] In this embodiment, when a job is submitted while the maintenance necessity detection operation is being announced or in progress, a job execution confirmation message is displayed and the maintenance necessity detection operation is prioritized. However, it may be possible to pre-configure the system to prioritize job execution.

[0118] Thus, in Example 3, if a job is submitted while a message indicating the operation of maintenance necessity detection or the operation of maintenance necessity detection is displayed, a message is displayed asking whether to skip or interrupt the maintenance necessity detection operation and execute the job. This reduces the possibility that a user may unintentionally interrupt the maintenance necessity detection by submitting a job.

[0119] 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.

[0120] 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 sheets in the charge adjustment device, and the sheets may be statically eliminated by the non-contact static elimination unit 58. Even in this case, it is preferable that the non-contact static elimination unit 58 performs maintenance necessity detection at an appropriate timing. In the charge adjustment device as well, by notifying the user that maintenance necessity detection is in operation on the display unit 56, the user can understand the operation status of maintenance necessity detection. This reduces the possibility that the user may unintentionally interrupt the maintenance necessity detection.

[0121] 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]

[0122] 52 Ionizer 58 Non-contact static elimination unit 66 Main unit display 98 Static Elimination Control Unit 200 Static eliminator

Claims

1. A non-contact static elimination unit is provided, which has an electrode section that generates ions and removes static electricity from the sheet in which an image has been formed in the image forming section without contacting the sheet. A control unit that performs a detection process to determine whether or not maintenance of the electrode section is required, A display unit that displays an indication that the aforementioned detection process is being executed, A static elimination device characterized by having the following features.

2. The static elimination device has a housing that accommodates the non-contact static elimination unit, The display unit is located on the outer surface of the housing. The static elimination device according to feature 1.

3. The control unit performs a static discharge process in which it discharges static electricity from a plurality of sheets transported from the image forming unit using the non-contact static discharge unit, and a detection process in which it detects whether or not maintenance of the electrode unit is required. The detection process is performed after the static elimination process. The static elimination device according to feature 1.

4. If a job is submitted while the aforementioned detection process is being executed, The display unit displays content that notifies the user that the detection process will be interrupted and the job will be executed. The static elimination device according to feature 1.

5. If a job is submitted while the aforementioned detection process is being executed, The display unit displays a screen that allows the user to choose to interrupt the detection process and execute the job. The static elimination device according to feature 1.

6. The display unit notifies that the detection process is in progress and also notifies a message that it does not recommend submitting a job. The static elimination device according to feature 1.

7. Based on the control unit's decision to execute the detection process, the display unit notifies the user of content indicating that the detection process will begin. The static elimination device according to feature 1.

8. The control unit decides to execute the detection process when the accumulated operating time of the non-contact static elimination unit exceeds a threshold. The static elimination device according to feature 7.

9. In the sheet transport direction, it is positioned downstream of the image forming unit and has a contact static elimination unit that eliminates static electricity from the sheet while in contact with it. The non-contact static elimination unit is located downstream of the contact static elimination unit in the sheet transport direction. The static elimination device according to feature 1.

10. The static elimination device according to claim 1, An image forming system comprising the image forming unit described above.

Images