Image forming apparatus

Abstract

To provide an image forming apparatus that can execute an image forming job if there is a remaining amount of a web, even if the image forming apparatus is powered off and then powered on after the remaining amount of the web reaches a predetermined remaining amount.SOLUTION: When an image forming apparatus is powered off and then powered on after the remaining amount of a web reaches a predetermined remaining amount (S12), the image forming apparatus determines whether to permit execution of an image forming job based on a change in an outer diameter of the web between the power-off period and the power-on period (S13). When the change in the outer diameter of the web 212 is larger than a predetermined threshold, the image forming apparatus regards that the remaining amount of the web is reduced from the power-off period until the power-on period, and determines as "near-end continuation disabled" and does not permit the execution of the image forming job (S14). On the other hand, when the change in the outer diameter of the web is equal to or less than the predetermined threshold, the image forming apparatus regards that the remaining amount of the web is not reduced, and permits the execution of the image forming job. In this way, even when the image forming apparatus is powered off and then powered on, a user can execute the image forming job if the remaining amount of the web is not reduced and there is a remaining amount of the web.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present invention relates to an image forming apparatus using electrophotographic technology such as a printer, a copier, a facsimile machine, or a multifunction peripheral.

Background Art

[0002] In an image forming apparatus, a toner image formed on a recording material is fixed to the recording material by heating and pressing with a fixing unit. However, when fixing the toner image, toner may adhere to the fixing roller (or pressure roller) of the fixing unit. For example, if toner adheres to the fixing roller, the recording material may be soiled by the toner. Therefore, a cleaning device having a cleaning web formed of a non-woven fabric (hereinafter simply referred to as a web) is used to remove the toner adhering to the fixing roller. In the case of such a cleaning device, the web is consumed while being wound up little by little. Conventionally, a notch is formed in the web, and when a flag member abutted against the web passes through the notch and is displaced, a photosensor can detect that the remaining amount of the web has reached a predetermined remaining amount (Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Incidentally, in image forming machines, users such as service technicians sometimes turn off the power to the machine to maintain the cleaning device. At that time, the user may re-stretch the web, which can reduce the amount of remaining web. Conventionally, even if the amount of remaining web decreases after it has reached a predetermined amount, it is difficult to detect the amount of web remaining after the decrease. Therefore, if an image forming job is executed after the web has been re-stretched and reached the predetermined amount, there was a risk that the web would be used up, causing the web to tear or resulting in image defects. For this reason, once the amount of remaining web reached a predetermined amount, it was designed so that an image forming job could not be executed until the web was replaced.

[0005] However, having to replace the web even when there is still web material remaining can lead to waste, and being unable to execute an image forming job until the web has been replaced can reduce the operational efficiency of the image forming machine. Therefore, there has been a need for a machine that can execute an image forming job even if the machine is turned off and then on again after the web has reached a predetermined amount, as long as there is still web material remaining. However, no such machine has yet been proposed.

[0006] In view of the above problems, the present invention aims to provide an image forming apparatus that can execute an image forming job even if the image forming apparatus is powered off and then powered on after the web has reached a predetermined remaining amount, as long as there is still web remaining. [Means for solving the problem]

[0007] An image forming apparatus according to one embodiment of the present invention is an image forming apparatus comprising an image forming unit that forms a toner image on a recording material, 1 A solid of rotation and The image forming unit comprises: a second rotating body which forms a nip portion together with the first rotating body and fixes a toner image to a recording material; a web which collects toner on the first rotating body; a supply roller on which the web is wound and which supplies the web for collecting toner on the first rotating body; a winding roller which winds up the web used for collecting toner on the first rotating body; a first contact member which contacts one end of the web; a detection unit which detects the outer diameter of the web wound on the winding roller or the web wound on the supply roller; and a control unit which controls the image forming unit, wherein the web has a notch formed in a part of the one end of the web in the width direction of the web, and the control unit which detects the first contact member which the notch If, after reaching the first ON state, the system transitions from the first ON state to the second ON state via the OFF state, and the difference between the outer diameter of the web last detected by the detection unit in the first ON state and the outer diameter of the web first detected by the detection unit in the second ON state is greater than or equal to a predetermined value, the system controls the image forming unit to prevent image formation. If, after the first contact member reaches the notch, the system transitions from the first ON state to the second ON state via the OFF state, and the difference between the outer diameter of the web last detected by the detection unit in the first ON state and the outer diameter of the web first detected by the detection unit in the second ON state is less than a predetermined value, the system allows the image forming unit to perform image formation. It is characterized by the following: Furthermore, an image forming apparatus according to another embodiment of the present invention is an image forming apparatus comprising: an image forming unit that forms a toner image on a recording material; a first rotating body; a second rotating body that forms a nip portion together with the first rotating body and fixes the toner image on the recording material; a web for collecting toner on the first rotating body; a supply roller on which the web is wound and which supplies the web for collecting toner on the first rotating body; a winding roller for winding the web used for collecting toner on the first rotating body; a detection unit that detects the outer diameter of the web wound on the winding roller or the web wound on the supply roller and detects the amount of the web used; and a control unit that outputs information regarding the replacement of the web when a predetermined amount of the web has been used, wherein the control unit The present invention relates to the following:, after the web has been used by a predetermined amount, if the state changes from a first ON state to a second ON state via an OFF state, and the difference between the outer diameter of the web last detected by the detection unit in the first ON state and the outer diameter of the web first detected by the detection unit in the second ON state is greater than or equal to a predetermined value, the present invention controls the image forming unit to prevent image formation from occurring; and, after the web has been used by a predetermined amount, if the state changes from a first ON state to a second ON state via an OFF state, and the difference between the outer diameter of the web last detected by the detection unit in the first ON state and the outer diameter of the web first detected by the detection unit in the second ON state is less than a predetermined value, the present invention relates to the present invention. [Effects of the Invention]

[0008] According to the present invention, even if the image forming apparatus is powered off and then powered on after the web has reached a predetermined remaining amount, an image forming job can be executed as long as there is remaining web. [Brief explanation of the drawing]

[0009] [Figure 1] A schematic diagram showing the configuration of the image forming apparatus according to this embodiment. [Figure 2] A schematic diagram showing the fixing unit and control block. [Figure 3] This is a top view illustrating the notch sensor unit, showing (a) before passing through the notch, (b) when displacing after passing through the notch, and (c) after passing through the notch. [Figure 4] This is a side view illustrating the operation of the notch sensor unit, showing (a) before detection and (b) after detection. [Figure 5] This is a side view showing the web outer diameter detection unit, (a) when the remaining web is small, and (b) when the remaining web is large. [Figure 6] A circuit diagram showing a rotary-type potentiometer. [Figure 7] This diagram illustrates a method for detecting the remaining amount of web, showing (a) the case of a comparative example and (b) the case of this embodiment. [Figure 8] A flowchart illustrating the web data remaining amount detection process. [Figure 9] A flowchart illustrating near-end continuation processing. [Figure 10] A flowchart illustrating near-end counter processing. [Modes for carrying out the invention]

[0010] <Image forming apparatus> One embodiment of the present invention will be described below. The image forming apparatus 100 shown in Figure 1 is a tandem-type intermediate transfer full-color printer in which yellow, magenta, cyan, and black image forming units Pa, Pb, Pc, and Pd are arranged along a rotating intermediate transfer belt 130.

[0011] In the image forming unit Pa, a yellow toner image is formed on the photosensitive drum 3a and transferred to the intermediate transfer belt 130. In the image forming unit Pb, a magenta toner image is formed on the photosensitive drum 3b and transferred to the intermediate transfer belt 130. In the image forming units Pc and Pd, cyan and black toner images are respectively formed on the photosensitive drums 3c and 3d and transferred to the intermediate transfer belt 130. The four-color toner images transferred to the intermediate transfer belt 130 are conveyed to the secondary transfer unit T2 and secondarily transferred to the recording material P. Examples of the recording material P include various types of sheet materials such as plain paper, thick paper, rough paper, embossed paper, coated paper, etc., plastic films, cloth, and the like.

[0012] The separation roller 16 separates the recording materials P pulled out from the cassette 10 one by one and sends them to the registration roller 12. The registration roller 12 sends the recording material P to the secondary transfer unit T2 in timing with the toner image on the intermediate transfer belt 130. The recording material P onto which the four-color toner images are secondarily transferred is heated and pressurized by the fixing unit 9, and the toner image is fixed on the surface.

[0013] In the case of single-sided printing, the recording material P on which the toner image is fixed by the fixing unit 9 is directly discharged to the discharge tray 163 . In the case of double-sided printing, the recording material P with the toner image fixed on the surface is conveyed to the reverse path, reversed front and back, and then fed to the registration roller 12 again. Then, the recording material P has the toner image transferred to the back surface at the secondary transfer unit T2, and after the toner image is fixed on the back surface by the fixing unit 9, it is discharged to the discharge tray 163.

[0014] <Image Forming Unit> The image forming units Pa, Pb, Pc, and Pd are substantially configured identically except that the colors of the toners used in the developing devices 1a, 1b, 1c, and 1d are different, being yellow, magenta, cyan, and black respectively. Therefore, hereinafter, the yellow image forming unit Pa will be described as a representative example, and the descriptions of the other image forming units Pb, Pc, and Pd will be omitted.

[0015] The image forming unit Pa surrounds the photosensitive drum 3a, and the charging device 2a, the exposure device La, the developing device 1a, the primary transfer roller 24a, and the drum cleaning device 4a are arranged. The photosensitive drum 3a is an electrophotographic photoreceptor in which a photosensitive layer is formed on the outer peripheral surface of, for example, an aluminum cylinder, and is rotated in the direction of arrow R1 at a predetermined process speed. The charging device 2a uniformly charges the surface of the photosensitive drum 3a to a predetermined potential in response to the application of a charging voltage from a power source (not shown). The exposure device La forms an electrostatic latent image on the photosensitive drum 3a by scanning a laser beam obtained by ON-OFF modulating a scanning line image signal developed with each color image with a rotating mirror (not shown). The developing device 1a develops the electrostatic latent image formed on the photosensitive drum 3a into a toner image using a developer.

[0016] The primary transfer roller 24a presses the intermediate transfer belt 130 to form a primary transfer portion between the photosensitive drum 3a and the intermediate transfer belt 130. When a primary transfer voltage is applied to the primary transfer roller 24a from a power source (not shown), the toner image on the photosensitive drum 3a is primarily transferred to the intermediate transfer belt 130. The intermediate transfer belt 130 is supported by being wound around the tension roller 15, the secondary transfer inner roller 14, and the driving roller 13, and is driven by the driving roller 13 to rotate in the direction of arrow A. The secondary transfer outer roller 11 abuts on the intermediate transfer belt 130 supported by the secondary transfer inner roller 14 to form a secondary transfer portion T2. When a secondary transfer voltage is applied to the secondary transfer outer roller 11 from a power source (not shown), the toner image on the intermediate transfer belt 130 is secondarily transferred to the recording material P passing through the secondary transfer portion T2. In the case of this embodiment, the image forming units Pa to Pd, the intermediate transfer belt 130, the primary transfer rollers 24a to 24d, the driving roller 13, the tension roller 15, the secondary transfer inner roller 14, and the secondary transfer outer roller 11 constitute an image forming unit 600 capable of forming a toner image on the recording material P.

[0017] The drum cleaning device 4a rubs a cleaning blade against the photosensitive drum 3a to collect the residual transfer toner remaining on the photosensitive drum 3a after primary transfer. The belt cleaning device 22 collects the residual transfer toner remaining on the intermediate transfer belt 130 after secondary transfer.

[0018] The main body of the device 100a is provided with an openable and closable door 500. With the door 500 open, the user can access the fixing unit 9 inside the main body of the device 100a from the outside, and perform maintenance work on the fixing unit 9, as well as replacement work on the cleaning web, which will be described later. An open / close sensor 710 is also provided to detect when the door 500 is opened or closed.

[0019] <Fuser Unit> Next, the configuration of the fuser unit 9 of this embodiment will be described with reference to Figure 2. The fuser unit 9 includes a fuser roller 201 for heating the toner image on the recording material P, a pressure roller 202 for pressurizing the recording material P, and a web unit 210 for cleaning the fuser roller 201. The fuser roller 201, as the first rotating body, is rotationally driven by a motor (not shown) or the like.

[0020] The fixing roller 201 and the pressure roller 202 each have a core metal formed in a cylindrical shape from, for example, aluminum or iron, an elastic layer made of silicone rubber formed on the outer surface of the core metal, and a release layer covering the outer surface of the elastic layer. The release layer is formed from a fluororesin tube such as tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) or polytetrafluoroethylene (PTFE).

[0021] A halogen heater 205 is positioned inside the fixing roller 201 to heat it. The surface temperature of the fixing roller 201 is detected by a thermistor 206, and the detected surface temperature is input to the control unit 150 (see Figure 1). The control unit 150 adjusts the temperature of the halogen heater 205 so that the surface temperature of the fixing roller 201 reaches the set temperature control temperature. In this embodiment, in order to accommodate various recording materials P, the temperature control temperature is set in the range of "135 to 200°C" according to the type of recording material P (more specifically, the basis weight).

[0022] The pressure roller 202, acting as a second rotating body, is pressed against the fuser roller 201 by a spring (not shown) or the like with a total pressure of approximately 784 N (approximately 80 kg), forming a fuser nip between it and the fuser roller 201. By pressing against the fuser roller 202, the pressure roller 202 rotates in conjunction with the rotating fuser roller 201. The recording material P on which the toner image is formed is held and conveyed by these rotating fuser rollers 201 and pressure roller 202, and as it passes through the fuser nip, heat and pressure are applied, fixing the toner image onto the recording material P.

[0023] <Web Unit> As described above, the fuser roller 201 is heated and has a high surface temperature, making it prone to toner (so-called offset toner) melted by heat on the recording material P adhering to it. Also, if the recording material P jams during the image forming operation, there is a risk that unfixed toner on the recording material P will adhere to the fuser roller 201. Therefore, a web unit 210 is provided to remove toner that has adhered to the fuser roller 201.

[0024] The web unit 210, as a cleaning unit, comprises a web supply roller 211, a cleaning web (hereinafter simply referred to as web 212), a recovery roller 204 that contacts the fixing roller 201, a web pressing roller 213, and a web winding roller 214. The web supply roller 211, as a supply unit, holds unused webs 212 and is able to supply the webs 212 to the friction position K with the recovery roller 204 by being driven by the web winding roller 214. The webs 212 are formed from a heat-resistant nonwoven fabric such as Nomex® or Himeron, with a width of 330 mm, a total length of 37,000 mm, and a thickness of 65 μm.

[0025] The web winding roller 214, which acts as the winding unit, is rotationally driven by the web drive motor 240 and winds up the used web 212 that has been fed out from the web supply roller 211. The web winding roller 214 winds up the web 212 so that the unused portion of the web 212 comes into contact with the recovery roller 204. The web 212 is stretched between the web supply roller 211 and the web winding roller 214 and is held in a removable state (rolled state) while wound up on the web winding roller 214.

[0026] The web pressing roller 213, acting as a pressing rotating body, is rotatably mounted and presses the web 212, fed from the web supply roller 211, against the recovery roller 204. Therefore, the web 212 comes into contact with the recovery roller 204. In other words, the web 212 does not directly rub against the fuser roller 201, but rather rubs against the recovery roller 204, which is in contact with the fuser roller 201 and rotates in its path. In this way, toner adhering to the fuser roller 201 is cleaned by the recovery roller 204 and indirectly removed by the web 212 via the recovery roller 204.

[0027] The recovery roller 204, acting as a rotating body (intermediate rotating body), is, for example, a rod-shaped metal component with a diameter of "20 mm," and its surface is made of stainless steel (SUS304) or the like. In this case, the release properties of the toner on the recovery roller 204 are lower than those of the release layer on the fuser roller 201, making it easier for toner to transfer from the fuser roller 201 to the recovery roller 204 and adhere to it. When the web 212 comes into contact with the recovery roller 204, the toner adhering to the recovery roller 204 (on the rotating body) is removed by the web 212. For example, the length of the nip formed by the fuser roller 201 and the recovery roller 204 in the rotational direction is approximately "2 mm," and the length of the nip formed by the recovery roller 204 and the web 212 in the rotational direction is approximately "8 mm."

[0028] By the way, in this embodiment, where the toner adhering to the fuser roller 201 is removed by the web 212, once the web 212 is used up, it is not possible to wind up the web 212 any further, and the recovery roller 204 will be repeatedly rubbed in the same place. In that case, the toner adhering to the fuser roller 201 will not be removed and will be carried along with the fuser roller 201, and may adhere to the recording material P during fixing, causing toner stains. Therefore, in order to prevent the web 212 from being used up, a mechanism is in place to detect when the remaining amount of web 212 has reached a predetermined amount. The configuration and operation of the notch sensor unit for detecting when the remaining amount of web 212 has reached a predetermined amount will be explained below using Figures 3(a) to 4(b).

[0029] <Notched Sensor Unit> As shown in Figure 3(a), the web 212 has a notch 212a formed in the direction of movement (winding direction). The notch 212a is formed on the edge of the web 212 in a direction intersecting the direction of movement. The notch sensor unit 300 is positioned in the movement path of the web 212 so as to be able to detect the notch 212a as the web 212 is wound up.

[0030] The notch sensor unit 300 has a flag 301 as a contact portion and a flag sensor 302 as a detection portion. The flag 301 is biased toward the web 212 by a spring (not shown) and is positioned to be displaceable so as to contact the web 212. The notch sensor unit 300 detects when the notch portion 212a has passed as the web 212 is wound up using the flag sensor 302. The flag sensor 302 as a detection sensor is a photosensor having a light-emitting portion and a light-receiving portion and is connected to the control unit 150 (see Figure 1) so as to be able to input and output signals.

[0031] As shown in Figure 3(a), when the flag 301 is in contact with the web 212, as shown in Figure 4(a), the flag 301 does not obstruct the space between the light-emitting part and the light-receiving part, and the flag sensor 302 is in a light-transmitting state (OFF) where the light emitted from the light-emitting part is received by the light-receiving part. On the other hand, as shown in Figures 3(b) and 3(c), when the contact state of the flag 301 is released, as shown in Figure 4(b), the flag 301 obstructs the space between the light-emitting part and the light-receiving part, and the flag sensor 302 changes to a light-shielding state (ON) where the light emitted from the light-emitting part is not received by the light-receiving part.

[0032] Then, from the starting end of the web 212 to the notch 212a, the contact state of the flag 301 is not released, and the flag sensor 302 is maintained in a light-transmitting state. On the other hand, when the notch 212a of the web 212 reaches the flag 301, the contact state of the flag 301 is released, and the flag sensor 302 transitions from a light-transmitting state to a light-blocking state. After that, as shown in Figure 3(c), the flag 301 remains displaced and does not return to its position before displacement, and the flag sensor 302 is maintained in the light-transmitting state shown in Figure 4(b).

[0033] In this way, as the flag 301 reaches the notch 212a, the flag sensor 302 changes from a light-transmitting state to a light-blocking state, allowing the notch sensor unit 300 to detect the notch 212a of the web 212. The notch 212a is formed, for example, at a position where the length from the starting end of the web 212 is "95%" of the total length of the web 212. For example, if the total length of the web 212 is "37000mm", the notch 212a will be formed at a predetermined position where the web length from the starting end of the web 212 is "35150mm", in other words, at a position where the remaining web is "1850mm". For example, if the amount of web 212 wound onto the web winding roller 214 is "0.1mm / sheet", the notch will be detected when the remaining web is "18500 sheets".

[0034] <Web outer diameter detection unit> In this embodiment, a web outer diameter detection unit 220 is provided to detect the outer diameter of the web 212 wound onto the web winding roller 214. The web outer diameter detection unit 220 will be described with reference to Figures 5(a) to 6. Figure 5(a) shows the state in which the web 212 has not yet been wound onto the web winding roller 214. Figure 5(b) shows the state in which the web 212 has been wound onto the web winding roller 214.

[0035] As shown in Figures 5(a) and 5(b), the web outer diameter detection unit 220, which serves as the outer diameter signal output unit, includes an outer diameter detection lever 221, a link gear 222, a two-stage gear 223, a rotary volume gear 224, and a rotary type volume resistor 225.

[0036] The outer diameter detection lever 221, which acts as a pivoting part, has one end that contacts the surface of the web 212 wound onto the web winding roller 214 with a pressure that does not affect the winding of the web 212, and the other end that contacts the link gear 222. The outer diameter detection lever 221 is provided so as to be pivotable according to the size of the outer diameter of the web 212 wound onto the web winding roller 214. Therefore, when one end is displaced according to the size of the outer diameter of the web 212, the other end pushes down on the link gear 222. As a result, the link gear 222 pivots in conjunction with the outer diameter detection lever 221.

[0037] The link gear 222 meshes with the two-stage gear 223, and when the link gear 222 oscillates in conjunction with the rotation amount of the outer diameter detection lever 221, the two-stage gear 223 rotates. The two-stage gear 223 also meshes with the rotary volume gear 224, and when the two-stage gear 223 rotates, the rotary volume gear 224 rotates. The gear shaft of the rotary volume gear 224 is a D-cut shaft and is engaged with the rotating part 225a of the rotary type volume resistor 225. Therefore, the rotating part 225a of the rotary type volume resistor 225 rotates in accordance with the rotation of the rotary volume gear 224.

[0038] Thus, in this embodiment, as the web 212 is wound up and the outer diameter of the web 212 wound onto the web winding roller 214 increases, the outer diameter detection lever 221 rotates counterclockwise. When the outer diameter detection lever 221 rotates, the rotating part 225a of the rotary potentiometer 225 is rotated via the link gear 222, the two-stage gear 223, and the rotary potentiometer gear 224. The rotary potentiometer 225 has terminals 1 to 3, and the resistance values ​​of the resistance R12 between terminals 1 and 2, and the resistance R23 between terminals 2 and 3 change depending on the rotation angle of the rotating part 225a.

[0039] As shown in Figure 6, terminals 1 to 3 of the rotary potentiometer 225 are connected to the control unit 150. Specifically, terminal 1 is connected to GND, terminal 2 is connected to an input terminal connected to the CPU 151 as the detection voltage Vsns, and terminal 3 is connected to a "3.3V" power supply. In this embodiment, the total resistance value R13 of the rotary potentiometer 225 (resistance value between terminals 1 to 3) is "10kΩ", and the resistance value R12 between terminals 1 to 2 and the resistance value R23 between terminals 2 to 3 change depending on the rotation angle of the rotating part 225a of the rotary potentiometer 225. That is, the resistance value "R13 = R12 + R23 = 10kΩ". The detection voltage Vsns input to the CPU 151 is the voltage obtained by the ratio of resistance value R12 and resistance value R23 from the "3.3V" applied by the power supply, and can be calculated from Equation 1 shown below. Vsns=3.3V×(R12)÷(R12+R23)...Formula 1

[0040] Thus, the web outer diameter detection unit 220 obtains the outer diameter of the web 212 wound onto the web winding roller 214 as a mechanical oscillation amount, and converts the mechanical oscillation amount into a detection voltage Vsns as a signal value using the rotary type volume resistor 225 as a conversion unit, and outputs it.

[0041] <Department Head> The image forming apparatus 100 includes a control unit 150, to which an operating unit 180, a web drive motor 240, and a web outer diameter detection unit 220 are connected, as shown in Figure 2. In addition to those shown in Figure 2, various other devices are connected to the control unit 150, such as motors that rotate the photosensitive drum and drive rollers, and power supplies that apply voltages such as charging voltage and primary transfer voltage, but these are not relevant to the main point of the invention and are therefore not shown or described here.

[0042] The control unit 150 controls various operations of the image forming apparatus 100, such as image forming operations, and has a CPU (Central Processing Unit) 151 and memory 152 such as ROM (Read Only Memory) and RAM (Random Access Memory). Various programs and data for controlling the image forming apparatus 100 are stored in memory 152. The CPU 151 can execute various programs stored in memory 152, such as image forming processing (not shown) and the "web remaining amount detection processing" (see Figure 8) described later. In addition, memory 152 can temporarily store calculation results and other data associated with the execution of various programs.

[0043] The control unit 150 is connected to an operation unit 180 provided on the main body 100a of the device. The operation unit 180 can input various information to the control unit 150 and display various information obtained from the control unit 150. The operation unit 180 is, for example, a touch panel, and the control unit 150 accepts input of various information, such as the start of an image forming job, in response to the user's operation of software keys displayed on the operation unit 180. The control unit 150 also displays various information such as replacement messages prompting replacement of the web 212, operation errors, and various executable programs on the operation unit 180 to present to the user. When presenting the user with a message to replace the web 212, the message may be presented not by displaying a replacement message on the operation unit 180, but by, for example, flashing LED lights or generating a warning sound from a speaker.

[0044] An image forming job refers to a series of operations from the start to the completion of the image forming operation based on a print signal for forming an image on a recording material P. In other words, it refers to a series of operations from the start of the preparatory operations necessary for image forming (so-called pre-rotation), through the image forming process, to the completion of the preparatory operations necessary for ending image forming (so-called post-rotation). Specifically, it refers to the period from the pre-rotation (preparatory operations before image forming) after receiving the print signal (receiving the image forming job) to the post-rotation (operations after image forming), including the image forming period and the time between sheets of paper.

[0045] Furthermore, the flag sensor 302 is connected to the control unit 150, and based on the flag sensor 302 detecting the displacement of the flag 301 (see Figure 3(b)), the control unit 150 outputs information regarding the remaining amount of web 212, indicating that the web 212 has reached a predetermined remaining amount. In addition, in this embodiment, a web replacement sensor 700 capable of detecting the replacement of the web 212 in the web unit 210 is provided and connected to the control unit 150. Based on the detection signal from the web replacement sensor 700, the control unit 150 can determine whether or not the web 212 has been replaced. Note that the open / close sensor 710 is connected to the control unit 150, and if the open / close sensor 710 detects the opening or closing of the door 500, it may be determined that maintenance work on the fixing unit 9 or replacement work on the web 212 has been performed.

[0046] As described above, the control unit 150 controls the web drive motor 240, which acts as a drive unit for rotating the web winding roller 214. The control unit 150 controls the web drive motor 240 so that the amount of web 212 wound up is a predetermined value (for example, 0.1 mm / sheet) each time a toner image is formed on a predetermined number of recording materials P. If a large amount of toner adheres to the fuser roller 201, it is preferable to control the web drive motor 240 so that the web 212 is fed out from the web supply roller 211 at a larger winding amount (for example, 0.5 mm / sheet). Alternatively, the web drive motor 240 may be controlled so that the amount of web 212 wound up is a predetermined value (for example, 0.1 mm / 10 sheets) each time a toner image is formed on multiple recording materials P.

[0047] Furthermore, as described above, in this embodiment, the web outer diameter detection unit 220 is configured to detect the outer diameter of the web 212 wound onto the web winding roller 214. The web outer diameter detection unit 220 uses an outer diameter detection lever 221 to mechanically obtain the web outer diameter of the web winding roller 214 as a oscillation amount, converts this oscillation amount into a voltage value (detection voltage Vsns) using a rotary type potentiometer resistor 225, and outputs it to the control unit 150.

[0048] Table 1 shows example table data for the outer diameter (mm) of the web 212, the detection voltage Vsns (V) of the rotary-type volume resistor 225, and the predicted web remaining amount (mm). This table data is pre-stored in memory 152. If the detection voltage Vsns is not listed in Table 1, the outer diameter of the web 212 and the predicted web remaining amount will be values ​​obtained by linearly interpolating two specified values ​​close to the actual detection voltage Vsns in Table 1. The control unit 150 can adjust the rotation amount of the web winding roller 214 by controlling the web drive motor 240 based on the predicted web remaining amount so that the amount of web 212 wound per turn is a predetermined value, regardless of the size of the web outer diameter. [Table 1]

[0049] Incidentally, in the image forming apparatus 100, the user may turn off the power and perform maintenance on the web unit 210. At that time, the user may re-tension the web 212, and the amount of remaining web decreases accordingly. In the comparative example, which does not have the web outer diameter detection unit 220 described above and detects when the amount of remaining web has reached a predetermined amount by the displacement of the flag 301 described above, it is difficult to detect the correct amount of remaining web even if the amount of remaining web decreases after the displacement of the flag 301. Here, the method of detecting the amount of remaining web in the comparative example will be explained using Figure 7(a), and the method of detecting the amount of remaining web in this embodiment will be explained using Figure 7(b).

[0050] In the comparative example, as shown in Figure 7(a), when there is a sufficient amount of web 212 remaining, that is, when the flag 301 has not passed through the notch 212a and is not displaced, the flag sensor 302 is in a light-transmitting state (OFF). When the flag sensor 302 changes from a light-transmitting state (OFF) to a light-blocking state (ON), the control unit 150 considers that the amount of web remaining has reached a predetermined amount, resulting in a "near-end state".

[0051] The control unit 150 can estimate the remaining amount of web even when it falls below a predetermined amount, by using a "near-end counter" which counts the number of times the web 212 has been wound, etc., from the "near-end state". The "near-end counter" is counted by the control unit 150 when the image forming apparatus 100 is powered on. When the control unit 150 determines that the "near-end state" is reached, requiring replacement of the web 212, when the "near-end counter" exceeds a predetermined end threshold. In other words, the "near-end state" indicates a state where the remaining amount of web 212 is below a predetermined amount, which is sufficient for image forming on a predetermined number of recording materials P. The "end state" indicates a state where the remaining amount of web is less than in the "near-end state", and there is a risk of running out of web 212 if a new image forming job is performed. In the comparative example, the control unit 150 distinguishes between the "near-end state" and the "end state" using the "near-end counter", and determines that the state has transitioned from the "near-end state" to the "end state" when the "near-end counter" becomes greater than, for example, the end threshold "50000".

[0052] However, in the comparative example, even if the web 212 is re-stretched during maintenance work on the web unit 210, the image forming apparatus 100 is powered off, so the "near-end counter" is not counted. In other words, the remaining web amount is updated when the image forming apparatus 100 is powered on, and not when it is powered off. Therefore, if the web 212 is re-wound while the power is off, it was difficult to estimate the remaining web amount.

[0053] If this is the case, errors may occur in the estimated remaining web capacity before and after power-on. Therefore, after detecting a "near-end state," the user is notified to replace the web 212, and the execution of new image forming jobs is not permitted until the web 212 is replaced. In other words, in the comparative example, when flag 301 shifted and a "near-end state" was detected, even if the user tried to continue executing image forming jobs after the completion of an ongoing image forming job, they could not execute a new image forming job until the web 212 was replaced. Thus, in the comparative example, after flag 301 shifted, the user was forced to replace the web 212 even though there was still web capacity remaining, resulting in wasted web 212.

[0054] In contrast, in this embodiment, as shown in Figure 7(b), after the remaining amount of web is detected by the notch sensor unit 300, the remaining amount of web 212 after the "near-end state" can be estimated using the outer diameter of the web 212 detected by the web outer diameter detection unit 220 and the "near-end counter". Furthermore, as will be described in detail later, if the power is turned off and then on after the "near-end state", the control unit 150 determines whether or not to execute the image forming job based on the change in the outer diameter of the web 212.

[0055] Furthermore, the detection voltage Vsns of the web outer diameter detection unit 220 (specifically the rotary-type potentiometer resistor 225) has limitations in accuracy because it may contain errors due to gear meshing and other factors. Therefore, as shown in Figure 7(b), instead of using the detection voltage Vsns of the web outer diameter detection unit 220 as is, it is divided into predetermined categories (for example, three categories: small, medium, and large) according to the outer diameter of the web 212 and used to determine the change in outer diameter. For example, in the outer diameter table data shown in Table 1, a web outer diameter of 20 mm or less corresponds to "small," a web outer diameter greater than 20 mm and 50 mm or less corresponds to "medium," and a web outer diameter greater than 50 mm corresponds to "large." The remaining amount determination data shown in Figure 7(b) is stored in memory 152 in advance.

[0056] Furthermore, as a method to improve the detection accuracy of the web outer diameter by the web outer diameter detection unit 220, there is a method of calibrating the detection voltage Vsns of the rotary-type volume resistor 225 at a reference point. In this embodiment, for example, the detection voltage of the rotary-type volume resistor 225 in the "near-end state" when the notch sensor unit 300 (specifically the flag sensor 302) is "ON" is stored in the memory 152 as a reference point and is used to calibrate the detection voltage Vsns from the "near-end state" onward. This allows for accurate detection of the outer diameter of the web 212 from the "near-end state" to the "end state". Alternatively, for example, when the notch sensor unit 300 is "OFF", i.e., in the "near-end state", the detection voltage of the rotary-type volume resistor 225 may be stored in the memory 152 as another reference point and used to calibrate the detection voltage Vsns from after the replacement of the web 212 up to the "near-end state".

[0057] <Web remaining balance determination process> Next, the "web remaining amount determination process" of this embodiment will be explained using Figures 8 to 10 with reference to Figures 2, 3, and 7. In this embodiment, the user turns off the power to the image forming apparatus 100 before performing maintenance work on the fixing unit 9, including, for example, rewinding the web 212, and turns on the power to the image forming apparatus 100 after the maintenance work. The "web remaining amount determination process" shown here is started by the control unit 150 and repeatedly executed in response to the image forming apparatus 100 being turned on after being turned off.

[0058] When the power to the main unit 100a of the device is turned on, the control unit 150 determines whether the notch sensor unit 300 is "OFF" or not (S1). If the notch sensor unit 300 is "OFF", that is, if the amount of web 212 has not reached a predetermined amount (Yes in S1), the control unit 150 detects that there is a sufficient amount of web 212 remaining (S2) and terminates the "web remaining amount determination process". If there is a sufficient amount of web 212 remaining, when the image forming job is being executed, the control unit 150 drives the web drive motor 240 to wind up a predetermined amount of web 212 using the web winding roller 214 each time a toner image is formed on a predetermined number of recording materials P.

[0059] If the notch sensor unit 300 is "ON", that is, if the flag 301 has been displaced in the notch portion 212a and the web 212 has reached a predetermined remaining length (No in S1), the control unit 150 determines whether or not "near-end continuation impossible" has already been set (S3). "Near-end continuation impossible" is set by the "near-end continuation process" described later (see Figure 8). If "near-end continuation impossible" has already been set (Yes in S3), the control unit 150 terminates the "web remaining length determination process".

[0060] If the setting is not "Near-end continuation impossible" (No in S3), the control unit 150 executes the "Near-end continuation process" described later (S4). After that, the control unit 150 determines whether or not the setting has been changed to "Near-end continuation impossible" following the execution of the "Near-end continuation process" (S5). If the setting is "Near-end continuation impossible" (Yes in S5), the control unit 150 terminates the "Web remaining amount determination process". If the setting is not "Near-end continuation impossible" (No in S5), the control unit 150 executes the "Near-end counter process" to determine whether the state has transitioned from "Near-end state" to "End state" based on the near-end counter (S6), and then terminates the "Web remaining amount determination process". The "Near-end counter process" will be described later (see Figure 10).

[0061] <Near-end continuation processing> The "near-end continuation process" (S4 in Figure 8) described above will be explained using Figure 9 with reference to Figure 2. First, the control unit 150 sets the web outer diameter detected by the web outer diameter detection unit 220 as the variable rol_Now in memory 152 (S11). Then, the control unit 150 determines whether or not the power has been turned off since the last time the "web remaining amount determination process" was executed (S12).

[0062] If the power has not been switched from off to on since the last processing (No in S12), the control unit 150 assumes that there is sufficient web remaining, sets the variable rol_Now to the variable rol_last, stores it in memory 152 (S15), and then returns to the "web remaining amount determination process" (see Figure 8). On the other hand, if the power has been switched from off to on since the last processing (Yes in S12), the control unit 150 compares the absolute value of the difference between the variables rol_Now and rol_last with the threshold end_th to determine whether the web outer diameter has changed (S13). Here, if the absolute value of the difference between the variables rol_Now and rol_last is greater than the threshold end_th, it is determined that the web outer diameter has changed before and after the power was turned on. The threshold end_th is set to a value that can determine the change in web outer diameter, for example, by taking into account the error of the web outer diameter detection unit 220 obtained experimentally.

[0063] If the web outer diameter has not changed (No in S13), the control unit 150 performs the process in step S15 described above and returns to the "web remaining amount determination process" (see Figure 8). On the other hand, if the web outer diameter has changed (Yes in S13), the control unit 150 sets "Near-end continuation not possible" (S14). In other words, when the image forming apparatus 100 is powered on, if the absolute difference between the signal value of the web outer diameter detection unit 220 output when the power was off (variable rol_last) and the signal value of the web outer diameter detection unit 220 output when the power was turned on (variable rol_Now) is greater than the threshold end_th, the control unit 150 sets "Near-end continuation not possible" and does not allow the execution of the image forming job. On the other hand, if the absolute difference between the signal value (variable rol_last) and the signal value (variable rol_Now) is less than or equal to the threshold end_th (less than or equal to the threshold), the control unit 150 does not set "Near-end continuation not possible" and allows the execution of the image forming job.

[0064] In other words, in this embodiment, if "near-end continuation not possible" is set, the control unit 150 will not permit the execution of the image forming job even if the operation unit 180 or the like inputs a command to start the image forming job. This is because when the power is turned off, the remaining amount of web 212 may have decreased below a predetermined amount, and if an image forming job is performed afterward, the use of web 212 may cause it to run out, potentially leading to tearing of web 212 or cleaning failures.

[0065] <Near-end counter processing> The "near-end counter processing" (S6 in Figure 8) described above will be explained using Figure 10 with reference to Figure 2. First, the control unit 150 determines whether the "near-end counter processing" is being performed for the first time since the "near-end state" was reached (S21). To determine whether it is the first execution, the control unit 150 can, for example, store in memory 152 that the next execution will be the first time when it determines that the "near-end state" is reached based on the detection result of the notch sensor unit 300.

[0066] If the "near-end counter processing" is not being performed for the first time (No in S21), the control unit 150 jumps to the processing in step S23. If the "near-end counter processing" is being performed for the first time (Yes in S21), the control unit 150 clears the "near-end counter" (S22) and proceeds to the processing in step S23. Here, the "near-end counter" specified by the variable end is cleared to "0".

[0067] In step S23, the control unit 150 determines whether a winding operation has been performed to wind up a predetermined amount of web 212 each time a predetermined number of toner images are formed on the recording material P after the previous execution of the "near-end counter processing". If the web 212 winding operation has not been performed (No in S23), the control unit 150 returns to the "web remaining amount determination processing" (see Figure 8). If the web 212 winding operation has been performed (Yes in S23), the control unit 150 increments the "near-end counter" to estimate the remaining web amount (variable end = variable end + 1, S24).

[0068] The "near-end counter" indicates the number of times the web 212 is wound after the web 212 reaches a predetermined remaining amount, and serves as an indicator of the cumulative value of the predetermined amount of web 212 wound after the web 212 reaches a predetermined remaining amount. In other words, multiplying the "near-end counter" by the "determined amount of web 212 wound" gives the amount of web 212 wound after the web 212 reaches a predetermined remaining amount. Here, "1" is added to the variable end each time the web 212 is wound, but this is not limited to this; for example, "2" may be added if the size of the recording material P or the image size is greater than a predetermined amount, or any additional value depending on the size ratio may be added.

[0069] The control unit 150 determines whether the "near-end counter" is greater than the end threshold (a predetermined number of times) (S25). If the "near-end counter" is less than or equal to the end threshold (No in S25), the control unit 150 returns to the "web remaining amount determination process". On the other hand, if the "near-end counter" is greater than the end threshold (Yes in S25), the control unit 150 sets it to "near-end continuation impossible" (S26) and returns to the "web remaining amount determination process". This is because, depending on the use of the web 212, it transitions from the "near-end state" to the "end state", and there is a risk that the web 212 will be used up if a new image formation job is performed.

[0070] As described above, in this embodiment, when the image forming apparatus 100 is powered off and then powered on after the web 212 has reached a predetermined remaining amount, a determination is made as to whether to allow the execution of the image forming job based on the change in the outer diameter of the web 212 between the power-off and power-on states. If the change in the outer diameter of the web 212 between the power-off and power-on states is less than or equal to a predetermined threshold, it is assumed that the web 212 was not rewound when the power was off, and that the remaining amount of web did not decrease between the power-off and power-on states, and the execution of the image forming job is permitted. On the other hand, if the change in the outer diameter of the web 212 between the power-off and power-on states is greater than a predetermined threshold, it is assumed that the web 212 was not rewound when the power was off, and that the remaining amount of web decreased between the power-off and power-on states, and the execution of the image forming job is not permitted.

[0071] As a result, even if the image forming apparatus 100 is powered off and then powered on after the web 212 has reached a predetermined remaining amount, an image forming job can be executed if there is still material remaining in the web 212. In other words, even after the web 212 has been replaced after reaching a predetermined remaining amount, if the remaining amount of web has not decreased between the time the power was turned off and on, the user can execute an image forming job without replacing the web 212, thus preventing waste of web. Furthermore, since an image forming job can be executed without waiting for the web to be replaced, the operational efficiency of the image forming apparatus 100 can be improved.

[0072] Furthermore, this technology can also be configured as follows. (1) An image forming apparatus, An image forming unit that forms a toner image on a recording material, A rotating body and A cleaning unit comprising: a web that rubs against the rotating body to remove toner from the rotating body; a supply unit capable of supplying the web to the position where it rubs against the rotating body; and a winding unit that winds up the web stretched between the supply unit and the supply unit. A drive unit that drives the winding unit, A detection unit that detects when the amount of web remaining reaches a predetermined amount, An outer diameter signal output unit that outputs a signal based on the outer diameter of the web wound onto the winding unit, The system includes a control unit capable of executing an image forming job by controlling the image forming unit to form a toner image on a recording material, The control unit, When the detection unit detects that the web has reached a predetermined remaining amount, and the image forming apparatus is turned on after being turned off, if the absolute difference between the signal value of the outer diameter signal output unit that was output when the image forming apparatus was turned off and the signal value of the outer diameter signal output unit that was output when the image forming apparatus was turned on is less than or equal to a predetermined threshold, the execution of the image forming job is permitted; if the absolute value is greater than the threshold, the execution of the image forming job is not permitted. An image forming apparatus characterized by the following features. (2) The web has a notch formed at the position indicating the predetermined remaining amount. The detection unit includes a contact portion that is displaceable so as to abut the web, and a detection sensor capable of detecting the displacement of the contact portion when it passes through the notch, and detects that the web has reached a predetermined remaining amount when the contact portion has passed through the notch and been displaced. The image forming apparatus according to (1) above, characterized in that (3) When the control unit is executing an image forming job, each time a toner image is formed on a predetermined number of recording materials, it drives the drive unit to wind up a predetermined amount of the web using the winding unit. If the number of times the web is wound up after the web reaches a predetermined remaining amount exceeds a predetermined number, the execution of the image forming job will not be permitted after the completion of the currently running image forming job. The image forming apparatus according to (1) or (2) above, characterized in that (4) The control unit controls the drive unit based on the signal value of the outer diameter signal output unit to adjust the rotation amount of the winding unit so that the amount of the web wound up in one cycle is a predetermined amount. The image forming apparatus according to (3) above, characterized in that (5) The outer diameter signal output unit includes an oscillating unit that contacts the surface of the web wound onto the winding unit and oscillates in accordance with the change in the outer diameter of the web, a rotating unit that rotates in accordance with the oscillating unit, and a conversion unit that changes the resistance value in accordance with the rotation of the rotating unit, converts the amount of oscillation of the oscillating unit into a voltage value, and outputs it as a signal based on the outer diameter of the web. The image forming apparatus according to any one of (1) to (4) above, characterized in that (6) An image forming unit that forms a toner image on a recording material, A fixing unit having a first rotating body and a second rotating body that forms a fixing nip portion that contacts the first rotating body to grip and transport the recording material, fixing the toner image formed on the recording material by the image forming unit to the recording material, The system comprises an intermediate rotating body positioned between the web and the first rotating body, which contacts the first rotating body to clean it. The rotating body is the intermediate rotating body. The image forming apparatus according to any one of (1) to (5) above, characterized in that (7) The system includes a pressing rotating body positioned between the supply unit and the winding unit, which presses the web toward the intermediate rotating body, The image forming apparatus according to (6) above, characterized in that [Explanation of symbols]

[0073] 9... Fixing unit, 100... Image forming apparatus, 150... Control unit, 201... First rotating body (fixing roller), 202... Second rotating body (pressure roller), 204... Rotating body (intermediate rotating body, recovery roller), 210... Cleaning unit (web unit), 211... Supply unit (web supply roller), 212... Web, 212a... Notch, 213... Pressing rotating body (web pressing roller), 214... Winding unit (web winding roller), 220... Outer diameter signal output unit (web outer diameter detection unit), 221... Oscillating unit (outer diameter detection lever), 225... Conversion unit (rotary type volume resistor), 240... Drive unit (web drive motor), 301... Contact unit (flag), 302... Detection sensor (flag sensor), 312... Detection unit (flag sensor), 600... Image forming unit, P... Recording material

Claims

1. An image forming apparatus, An image forming unit that forms a toner image on a recording material, The first rotating body and, A second rotating body, together with the first rotating body, forms a nip portion and fixes the toner image to the recording material, A web for collecting toner on the first rotating body, The web is wound around a supply roller that supplies the web to collect toner on the first rotating body, A winding roller for winding up the web used to collect toner on the first rotating body, A first contact member that contacts one end of the web, A detection unit for detecting the outer diameter of the web wound on the winding roller or the web wound on the supply roller, The system comprises a control unit for controlling the image forming unit, The web has a notch formed in a part of one end of the web in the width direction of the web, The control unit, If, after the first contact member reaches the notch, the state changes from a first ON state to an OFF state and then to a second ON state, and the difference between the outer diameter of the web detected by the detection unit at the end of the first ON state and the outer diameter of the web detected by the detection unit at the beginning of the second ON state is greater than or equal to a predetermined value, the image forming unit is controlled so that image formation does not occur. If, after the first contact member reaches the notch, the state changes from the first ON state to the second ON state via the OFF state, and the difference between the outer diameter of the web detected by the detection unit at the end of the first ON state and the outer diameter of the web detected by the detection unit at the beginning of the second ON state is less than a predetermined value, then the image forming unit is permitted to form an image. An image forming apparatus characterized by the following:

2. The collection roller further comprises contacting the web and the first rotating body and collecting toner on the first rotating body, The first rotating body contacts the recovery roller but does not contact the web, so that the toner on the first rotating body is recovered to the web via the recovery roller. The image forming apparatus according to feature 1.

3. The detection unit has a second contact member that contacts the web wound on the winding roller, and detects the outer diameter of the web by detecting the position of the second contact member. The image forming apparatus according to feature 1.

4. The detection unit has a variable resistor, The variable resistor changes its resistance according to the position of the second contact member. The image forming apparatus according to feature 3.

5. The detection unit detects the outer diameter of the web wound on the winding roller, The image forming apparatus according to feature 1.

6. The first contact member further comprises a display unit that prompts a warning to replace the web when it reaches the notch. The image forming apparatus according to feature 1.

7. The detection unit detects the outer diameter of the web wound on the winding roller or the web wound on the supply roller while the web is being wound up. The image forming apparatus according to feature 1.

8. An image forming apparatus, An image forming unit that forms a toner image on a recording material, The first rotating body and, A second rotating body, together with the first rotating body, forms a nip portion and fixes the toner image to the recording material, A web for collecting toner on the first rotating body, The web is wound around a supply roller that supplies the web to collect toner on the first rotating body, A winding roller for winding up the web used to collect toner on the first rotating body, A detection unit that detects the outer diameter of the web wound on the winding roller or the web wound on the supply roller, and detects the amount of web used, The system includes a control unit that outputs information regarding the replacement of the web when a predetermined amount of the web has been used, The control unit, If, after the web has been used by a predetermined amount, the system transitions from a first ON state to an OFF state and then to a second ON state, and the difference between the outer diameter of the web detected by the detection unit at the end of the first ON state and the outer diameter of the web detected by the detection unit at the beginning of the second ON state is greater than or equal to a predetermined value, the image forming unit is controlled to prevent image formation from taking place. If, after the web has been used by the predetermined amount, the state changes from the first ON state to the second ON state via the OFF state, and the difference between the outer diameter of the web detected by the detection unit at the end of the first ON state and the outer diameter of the web detected by the detection unit at the beginning of the second ON state is less than a predetermined amount, then the image forming unit is permitted to form an image. An image forming apparatus characterized by the following:

Images