JP2008051887A - Cleaning device using web sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a web sheet from being torn or meandered by suppressing deflection of a feed roller and a take-up roller, regardless of a quantity of web sheet wound around the rollers. <P>SOLUTION: Although the feed roller 62 and take-up roller 63 use a common rotating mechanism, a brake member 79 applies brake to the rollers, around which a sufficient amount of web sheet 61 is wound; consequently, the roller around which web sheet 61 will not be wound or the roller around which almost no web sheet 61 is wound decrease in the rotation load, and such rollers are prevented from deflecting; and this prevents the web sheet 61 from being torn or meandered. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cleaning device using a web sheet suitable for cleaning a fixing roller of a fixing device in, for example, an electrophotographic image forming apparatus.

  In recent years, the processing speed of image forming apparatuses has been increased. For example, up to several years ago, the number of sheets to be printed was 50 to 70 sheets / minute (A4 paper horizontal conveyance), but recently, the number has increased to 100 to 120 sheets / minute (A4 paper horizontal conveyance). There is a direction to move from the field of forming equipment to the field of light printing.

  In such a device, the fouling of the fixing roller of the fixing device is increasing. This is because as the number of print processed sheets increases, the total amount of residual toner attached to the fixing roller also increases. Conventionally, residual toner on the fixing roller has been removed by blade cleaning, felt cleaning, etc., but if the fixing roller becomes dirty, even if the residual toner on the fixing roller is removed by such a method, the toner remains on the blade or felt. The toner once adhered may return to the fixing roller, and the cleaning lifetime is not sufficient for the period of use of the fixing device. For this reason, it is necessary to provide another method.

For example, a web cleaning technique has been proposed. In this web cleaning method, a web sheet made of a thin cloth is wound around a feed roller, one end of the web sheet is connected to the take-up roller, the web sheet is sent out from the feed roller, and taken up on the take-up roller. In the course of feeding and winding, the web sheet is brought into contact with the fixing roller to remove deposits on the fixing roller (see Patent Document 1). If a web sheet having a sufficient length is used, the useful life of cleaning becomes longer.
JP 2006-106347 A

  By the way, in the above-mentioned patent document 1, in order to prevent the web sheet feed amount and the winding amount from being excessive or insufficient, the feed roller and the take-up roller are rotationally controlled separately.

  However, when the rotational drive control of the feed roller and the take-up roller is performed separately as described above, the drive mechanism and control are complicated.

  For this reason, it is conceivable to simplify the driving mechanism of each roller by sharing the driving mechanism among the rollers. In this case, each roller rotates synchronously, and a deviation occurs between the web sheet feeding amount and the winding amount. Therefore, it is necessary to provide a tension mechanism or the like for absorbing the deviation amount.

  However, in the configuration in which the driving mechanism is shared between the rollers as described above, a load interacts between each roller and the web sheet. However, this load may become an overload for one of the rollers. As a result, the one roller is bent, which causes wrinkling and overloading of the web sheet, and breaks or meanders the web sheet.

  Here, for both the feed roller and the take-up roller, the strength of the entire roller is high if the amount of web sheet wound is large, and the strength of the entire roller is low if the amount of web sheet wound is small. . For example, in the first period of use of the web sheet, the web sheet amount wound around the feeding roller is large, the web sheet amount wound around the winding roller is small, the strength of the whole feeding roller is high, and the strength of the whole winding roller. Becomes lower. For this reason, an overload is easily applied to the take-up roller, and the take-up roller may bend. On the other hand, in the latter stage of use of the web sheet, the amount of the web sheet wound around the feeding roller is reduced, and the amount of the web sheet wound around the take-up roller is increased. For this reason, an overload is easily applied to the feed roller, and the feed roller may bend. Such bending of the feed roller and the take-up roller causes wrinkling and overloading of the web sheet, and the web sheet is broken or meandered.

  Therefore, the present invention has been made in view of the above-described conventional problems, regardless of the amount of web sheet wound around the feed roller and the take-up roller, and suppressing the bending of each roller, It is an object of the present invention to provide a cleaning device using a web sheet that can prevent meandering.

  In order to solve the above-described problems, the present invention includes a feed roller around which a web sheet is wound, and a take-up roller connected to one end of the web sheet, and the web sheet is fed from the feed roller and taken up by the take-up roller. In the cleaning apparatus using the web sheet that removes the deposits on the other roller by bringing the web sheet into contact with the other roller during the feeding and winding, the amount of winding of the web sheet of the feeding roller is reduced. In addition, a rotation load control means is provided for controlling a rotation load acting on the feed roller or the take-up roller in a process in which the take-up amount of the web sheet of the take-up roller increases.

  For example, the rotational load control means is a friction member that contacts an end surface of a web sheet layer wound around the feed roller, or a friction member that contacts an end surface of the web sheet layer wound around the winding roller.

  The friction member that comes into contact with the end face of the web sheet layer wound around the feed roller controls the rotational load acting on the feed roller or the take-up roller during the first half of use of the web sheet.

  Or the friction member which contacts the end surface of the web sheet layer wound up by the said winding roller controls the rotational load which acts on the said sending roller or the said winding roller in the latter half use period of a web sheet.

  According to the present invention having such a configuration, the rotation load control means is configured to reduce the amount of winding of the web sheet of the feeding roller and increase the amount of winding of the web sheet of the winding roller. The rotational load acting on the take-up roller is controlled. For this reason, when the web sheet amount wound around the feed roller or the take-up roller is small and the strength of the entire roller is lowered, the rotational load acting on the roller is reduced to prevent the roller from being bent. be able to. As a result, the web sheet does not wrinkle or overload due to the deflection of the roller, and the web sheet does not break or meander.

  For example, the rotational load control means is a friction member that comes into contact with the end face of the web sheet layer wound around the feed roller, or a friction member that comes into contact with the end face of the web sheet layer wound around the take-up roller. Here, when the amount of web sheet wrapping around the roller is large, the area of the end surface of the web sheet layer increases, so the frictional force between the end surface of the web sheet layer and the friction member increases, and this frictional force causes the rotation of the roller. It becomes a load and the rotational driving force of the roller is canceled and suppressed. Conversely, when the amount of web sheet wrapping around the roller is small, the area of the end surface of the web sheet layer decreases, so the frictional force between the end surface of the web sheet layer and the friction member decreases, and the rotational driving force of the roller is almost suppressed. It will not be done. With such a simple configuration, the rotational load acting on the roller can be controlled.

  Further, the friction member that comes into contact with the end surface of the web sheet layer wound around the feed roller controls the rotational load acting on the feed roller or the take-up roller during the first period of use of the web sheet. As a result, the rotational driving force of the feeding roller is canceled and suppressed, and accordingly, the rotational load acting on the winding roller in the empty or near empty state is reduced during the first half of the use of the web sheet. Bending can be prevented.

  Or the friction member which contacts the end surface of the web sheet layer wound up by the winding roller controls the rotational load which acts on the feeding roller or the winding roller in the latter stage of use of the web sheet. As a result, the rotational driving force of the take-up roller is canceled and suppressed, and accordingly, the rotational load acting on the empty or nearly empty feed roller is reduced in the latter half of the use of the web sheet, and the deflection of the feed roller is reduced. Can be prevented.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic view showing an image forming apparatus to which the first embodiment of the cleaning apparatus of the present invention is applied. As will be described later, the cleaning device of the present embodiment is applied to a fixing device in an image forming apparatus, and is used to remove dirt on a heating roller of the fixing device.

  The image forming apparatus 100 acquires image data read from a document sheet, or acquires image data received from the outside, and forms a monochrome image indicated by the image data on a recording sheet. The configuration is roughly divided into an original paper transport unit (ADF) 101, an image reading unit 102, a printing unit 103, a recording paper transport unit 104, and a paper feed unit 105.

  When at least one document sheet is set on the document set tray 11 in the document sheet transport unit 101, the document sheet is pulled out from the document set tray 11 and transported one by one. The original paper is guided to the reading window 102a and passed, and the original paper is discharged to the paper discharge tray 12.

  A CIS (Contact Image Sensor) 13 is disposed above the document reading window 102a. The CIS 13 repeatedly reads an image on the back side of the original paper in the main scanning direction when the original paper passes through the original reading window 102a, and outputs image data indicating the image on the back side of the original paper.

  The image reading unit 102 exposes the surface of the original paper by the lamp of the first scanning unit 15 when the original paper passes through the original reading window 102a, and the original by the mirrors of the first and second scanning units 15 and 16. Reflected light from the paper surface is guided to the imaging lens 17, and an image on the surface of the original paper is formed on a CCD (Charge Coupled Device) 18 by the imaging lens 17. The CCD 18 repeatedly reads an image on the surface of the original paper in the main scanning direction, and outputs image data indicating the image on the surface of the original paper.

  Further, when the original paper is placed on the platen glass on the upper surface of the image reading unit 102, the first and second scanning units 15 and 16 are moved while maintaining a predetermined speed relationship with each other, so that the first scanning unit 15 The surface of the original paper on the platen glass is exposed by the first and second scanning units 15 and 16, and the reflected light from the original paper surface is guided to the imaging lens 17. An image is formed on the CCD 18.

  The image data output from the CIS 13 or the CCD 18 is subjected to various image processing by a control circuit such as a microcomputer and then output to the printing unit 103.

  The printing unit 103 records a document indicated by image data on a sheet, and includes a photosensitive drum 21, a charger 22, an optical writing unit 23, a developing unit 24, a transfer unit 25, a cleaning unit 26, and a fixing device. 27 etc.

  The photosensitive drum 21 rotates in one direction, and after the surface is cleaned by the cleaning unit 26, the surface is uniformly charged by the charger 22. The charger 22 may be of a charger type or of a roller type or a brush type that contacts the photosensitive drum 21.

  The optical writing unit 23 is a laser scanning unit (LSU) including two laser irradiation units 28a and 28b and two mirror groups 29a and 29b. In the optical writing unit 23, image data is input, laser light corresponding to the image data is emitted from the laser irradiation units 28a and 28b, and the laser light is transmitted through the mirror groups 29a and 29b. The drum 21 is irradiated to expose the uniformly charged surface of the photosensitive drum 21 to form an electrostatic latent image on the surface of the photosensitive drum 21.

  The optical writing unit 23 employs a two-beam method including two laser irradiation units 28a and 28b in order to cope with high-speed printing processing, thereby reducing the burden associated with increasing the irradiation timing.

  As the optical writing unit 23, an EL writing head or an LED writing head in which light emitting elements are arranged in an array can be used instead of the laser scanning unit.

  The developing device 24 supplies toner to the surface of the photosensitive drum 21 to develop the electrostatic latent image, and forms a toner image on the surface of the photosensitive drum 21. The transfer unit 25 transfers the toner image on the surface of the photosensitive drum 21 onto the recording paper conveyed by the paper conveyance unit 104. The fixing device 27 heats and pressurizes the recording paper to fix the toner image on the recording paper. Thereafter, the recording sheet is further conveyed to the sheet discharge tray 47 by the sheet conveying unit 104 and discharged. The cleaning unit 26 removes and collects the toner remaining on the surface of the photosensitive drum 21 after development and transfer.

Here, the transfer unit 25 includes a transfer belt 31, a drive roller 32, a driven roller 33, an elastic conductive roller 34, and the like, and the transfer belt 31 is stretched between the rollers 32 to 34 and other rollers. Is rotating. The transfer belt 31 has a predetermined resistance value (for example, 1 × 10 ⁹ to 1 × 10 ¹³ Ω / cm), and conveys the recording paper placed on the surface thereof. The elastic conductive roller 34 is pressed against the surface of the photosensitive drum 21 via the transfer belt 31, and presses the recording paper on the transfer belt 31 against the surface of the photosensitive drum 21. An electric field having a polarity opposite to the charge of the toner image on the surface of the photosensitive drum 21 is applied to the elastic conductive roller 34, and the toner image on the surface of the photosensitive drum 21 is transferred onto the transfer belt 31 by the electric field having the opposite polarity. Is transferred onto the recording paper. For example, when the toner image has a charge of (−) polarity, the polarity of the electric field applied to the elastic conductive roller 34 is set to (+) polarity.

  The fixing device 27 includes a heating roller 35 and a pressure roller 36. Pressure members (not shown) are arranged at both ends of the pressure roller 36 so that the pressure roller 36 is pressed against the heating roller 35 with a predetermined pressure. When the recording paper is conveyed to a pressure contact area (referred to as a nip area) between the heating roller 35 and the pressure roller 36, the recording paper is conveyed by the rollers 35 and 36, and unfixed toner on the recording paper. The image is heated and melted and pressed to fix the toner image on the recording paper.

  The paper transport unit 104 includes a plurality of pairs of transport rollers 41, a pair of registration rollers 42, a transport path 43, reverse transport paths 44a and 44b, a plurality of branching claws 45, and a pair of paper discharge rollers 46 for transporting recording paper. Etc.

  In the conveyance path 43, the recording paper is received from the paper supply unit 105, and the recording paper is conveyed until the leading edge of the recording paper reaches the registration roller 42. At this time, since the registration roller 42 is temporarily stopped, the leading edge of the recording paper reaches and contacts the registration roller 42, and the recording paper is bent. The leading edge of the recording sheet is aligned parallel to the registration roller 42 by the elastic force of the bent recording sheet. Thereafter, the rotation of the registration roller 42 is started, the recording paper is conveyed to the transfer unit 25 of the printing unit 103 by the registration roller 42, and the recording paper is further conveyed to the paper discharge tray 47 by the paper discharge roller 46.

  The registration roller 42 is stopped and rotated by switching on and off the clutch between the registration roller 42 and the drive shaft, or by switching on and off the motor that is the drive source of the registration roller 42.

  Also, when recording an image on the back side of the recording paper, each branch claw 45 is selectively switched, the recording paper is guided from the transport path 43 to the reverse transport path 44b, and the transport of the recording paper is temporarily stopped. Further, each of the branch claws 45 is selectively switched again, the recording sheet is guided from the reverse conveying path 44b to the reverse conveying path 44a, the recording sheet is reversed, and the recording sheet is conveyed through the reverse conveying path 44a. Return to the registration roller 42 in the path 43.

  Such conveyance of the recording paper is referred to as switchback conveyance. By this switchback conveyance, the front and back of the recording paper can be reversed, and at the same time, the leading edge and the trailing edge of the recording paper are also switched. Accordingly, when the recording paper is reversed and returned, the trailing edge of the recording paper comes into contact with the registration roller 42 and the trailing edge of the recording paper is aligned in parallel with the registration roller 42. Is transferred to the transfer unit 25 of the printing unit 103 to perform printing on the back surface of the recording paper, and the unfixed toner image on the back surface of the recording paper is heated and melted by the nip area between the rollers 35 and 36 of the fixing device 27. The toner image is fixed on the back surface of the recording sheet by the pressure, and then the recording sheet is conveyed to the discharge tray 47 by the discharge roller 46.

  In the conveyance path 43 and the reverse conveyance paths 44a and 44b, sensors for detecting the position of the recording paper and the like are arranged at various locations, and the conveyance roller and the registration roller are driven and controlled based on the position of the recording paper detected by each sensor. Thus, the recording paper is conveyed and positioned.

  The paper feed unit 105 includes a plurality of paper feed trays 51. Each paper feed tray 51 is a tray for accumulating recording paper, and is provided below the image forming apparatus 100. Each paper feed tray 51 is provided with a pick-up roller or the like for pulling out recording sheets one by one, and sends out the pulled recording sheets to the transport path 43 of the paper transport unit 104.

  Since the image forming apparatus 100 is intended for high-speed printing processing, each paper feed tray 51 has a capacity capable of storing 500 to 1500 standard size recording sheets.

  Further, on the side surface of the image forming apparatus 100, a large-capacity paper feed cassette (LCC) 52 capable of storing a large amount of a plurality of types of recording papers and a manual feed tray 53 for mainly supplying irregular-size recording papers are provided. ing.

  The paper discharge tray 47 is disposed on the side surface opposite to the manual feed tray 53. In place of the paper discharge tray 47, a post-processing device for paper discharge (such as stapling and punching) and a plurality of paper discharge trays can be arranged as options.

  In such an image forming apparatus 100, the printing process speed is increased to improve usability. For example, when A4 standard recording paper is used, the recording paper conveyance speed is set to 70 sheets / minute (process speed 350 mm / sec).

  In the fixing device 27, when the recording paper conveyance speed or process speed becomes high, a sufficient amount of heat cannot be applied to the recording paper passing through the nip region between the heating roller 35 and the pressure roller 36, or each roller. The surface temperatures of 35 and 36 tend to decrease. If this is left as it is, fixing failure of the toner image on the recording paper occurs.

  For this reason, in the fixing device 27, a heater is incorporated in each of the rollers 35 and 36 to heat the rollers 35 and 36. Further, an external heating unit 48 for heating the heating roller 35 from the outside is provided, and the heating roller 35 is directly heated by the external heating unit 48, and the pressure roller 36 is also indirectly transmitted by heat conduction between the rollers 35 and 36. Thus, the surface temperature of each of the rollers 35 and 36 is suppressed from decreasing, and the surface temperature is maintained at a specified fixing temperature.

  FIG. 2 is a cross-sectional view schematically showing the fixing device 27 as viewed from the side. The fixing device 27 includes a heating roller 35, a pressure roller 36, an external heating unit 48 that heats the heating roller 35 from the outside, and a cleaning device 49 that removes toner adhering to the surface of the heating roller 35.

  The rollers 35 and 36 are brought into pressure contact with each other with a predetermined pressing force (for example, 600 N), and a nip region N is formed between them. The length of the nip area N (the length along the rotation direction of the rollers 35 and 36) is set to 9 mm, for example. Each of the rollers 35 and 36 rotates while being heated to a specified fixing temperature (for example, 180 ° C.), and heats and melts the toner image on the recording paper P passing through the nip area N.

  The heating roller 35 is a three-layered roller in which an elastic layer is provided on the outer peripheral surface of the core metal, and a release layer is formed on the outer peripheral surface of the elastic layer. For the core metal, for example, a metal such as iron, stainless steel, aluminum, copper, or an alloy thereof is used. Silicon rubber is used for the elastic layer, and fluorine resin such as PFA (copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether) or PTFE (polytetrafluoroethylene) is used for the release layer.

  Inside the heating roller 35 (inside the cored bar), a heater lamp (halogen lamp) 43 serving as a heat source for heating the roller 35 is provided.

  Similarly to the heating roller 35, the pressure roller 36 is also composed of a metal core such as iron, stainless steel, aluminum, copper, or an alloy thereof, an elastic layer such as silicon rubber on the surface of the metal core, and further thereon. This is a three-layered roller composed of a release layer such as PFA or PTFE.

  A heater lamp 44 for heating the roller 36 is also provided inside the pressure roller 36 (inside the cored bar).

  The heater lamps 43 and 44 of the rollers 35 and 36 are controlled to be turned on and off, and emits infrared rays when they are turned on to heat the rollers 35 and 36. Each of the rollers 35 and 36 is heated from inside thereof, and their surfaces are heated uniformly.

  The external heating unit 48 includes an endless heating belt 51 and a pair of external heating rollers 52 and 53. The endless heating belt 51 is stretched between the external heating rollers 52 and 53.

  An endless heating belt 51 is formed on a surface of a hollow cylindrical base material made of a heat-resistant resin such as polyimide or a metal material such as stainless steel or nickel, and a synthetic resin material (for example, PFA or PTFE) having excellent heat resistance and releasability. A two-layer belt in which a release layer made of a fluororesin) is formed. In order to reduce the shifting force of the endless heating belt 51, the inner peripheral surface of the belt base material may be coated with a fluorine resin or the like.

  The external heating rollers 52 and 53 are hollow cylindrical metal cores made of aluminum or iron-based material. In order to reduce the shifting force of the endless heating belt 51, the surface of the metal core material may be coated with a fluororesin or the like.

  In addition, heater lamps 54 and 55 for heating the rollers 52 and 53 are provided inside the external heating rollers 52 and 53, respectively. The heater lamps 54 and 55 are controlled to be turned on and off, and emit infrared rays to heat the rollers 52 and 53 when turned on. Each of the rollers 52 and 53 is heated from inside thereof, and their surfaces are heated uniformly. Then, heat is conducted from the surface of each roller 52 to the endless heating belt 51, and when the endless heating belt 51 rotates together with the rollers 52 and 53, the entire endless heating belt 51 is heated uniformly.

  A thermistor 56 is disposed in the vicinity of the peripheral surface of the heating roller 35, and the surface temperature of the heating roller 35 is detected by the thermistor 56.

  Here, the heating roller 35 is driven to rotate in the direction indicated by the arrow D, with its shaft being rotated by a motor and a power transmission mechanism (not shown). Since the pressure roller 36 is in pressure contact with the heating roller 35, the pressure roller 36 is driven to rotate in the direction indicated by the arrow E. Further, the endless heating belt 51 of the external heating unit 48 is driven to rotate in the direction indicated by the arrow F when in contact with the heating roller 35. Thereby, the heating roller 35, the pressure roller 36, and the endless heating belt 51 rotate synchronously with each other.

  Further, based on the surface temperature of the heating roller 35 detected by the thermistor 56, the heater lamps 43 and 44 of the heating roller 35 and the pressure roller 36 and the heater lamps 54 and 55 of the external heating rollers 52 and 53 are controlled on and off. The surface temperature of the heating roller 35 and the pressure roller 36 and the surface temperature of the endless heating belt 51 are adjusted. As a result, the surface temperature of each roller is accurately controlled, and the toner image on the recording paper can be reliably fixed.

  On the other hand, when the number of print processing sheets increases, the total amount of residual toner adhering to the heating roller 35 also increases, and the residual toner on the heating roller 35 cannot be reliably removed by blade cleaning, felt cleaning, or the like. For this reason, the cleaning device 49 of this embodiment is applied.

  The cleaning device 49 includes a feed roller 62 around which a web sheet 61 made of a thin (around 100 μm thickness) cloth impregnated with oil (silicone oil) is wound, a take-up roller 63 to which the tip of the web sheet 61 is connected, A plurality of tension rollers 64 that apply tension to the web sheet 61 in the conveyance path of the web sheet 61 from the feed roller 62 to the take-up roller 63, and the web sheet 61 is heated between the feed roller 62 and the take-up roller 63. A pressure roller 65 that presses against the roller 35 is provided. The web roller 61 is pressed against the surface of the heating roller 35 by the pressure roller 65, and residual toner adhering to the surface of the heating roller 35 is wiped off.

  The web sheet 61 is pressed against the surface of the heating roller 35 by the pressing roller 65 in the nip region between the pressing roller 65 and the heating roller 35. When the web sheet 61 portion in the nip area is contaminated with the residual toner on the surface of the heating roller 61 and it becomes difficult to remove the residual toner by the web sheet 61 portion, the feeding roller 62 and the take-up roller 63 are rotated by a certain amount. Thus, the web sheet 61 is fed by a certain amount from the feed roller 62 to the take-up roller 63, and the web sheet 61 portion in the nip area is renewed, and the residual toner can be removed by the new web sheet 61 portion.

  Further, every time a certain amount of toner is consumed, it is considered that it is difficult to remove the residual toner by the web sheet 61 portion in the nip area, and the feeding roller 62 and the take-up roller 63 are rotated by a certain amount, and the nip area The web sheet 61 part is renewed. Accordingly, the feed roller 62 and the take-up roller 63 are rotationally driven intermittently.

  FIG. 3A is a plan view schematically showing the periphery of the feed roller 62 and the take-up roller 63.

  The feed roller 62 and the take-up roller 63 are rotatably supported at both ends thereof, and drive gears 67 and 68 are fixed to one end of each of the rollers 62 and 63. Respective rotation load control units 71 and 72 are provided at the ends.

  A gear 74 and a transmission gear 75 fixed to the output shaft of the drive motor 73 are meshed with the drive gear 68 of the take-up roller 63, and a drive gear 67 of the feed roller 62 is meshed with the transmission gear 75. When the gear 74 of the drive motor 73 is rotated in a predetermined direction, the rotation of the gear 74 is sequentially transmitted to the drive gear 68 of the take-up roller 63, the transmission gear 75, and the drive gear 67 of the feed roller 62, and the feed roller. 62 and the take-up roller 63 are both driven to rotate in the direction of arrow A in FIG. With such a configuration, the rotational drive mechanisms of the feed roller 62 and the take-up roller 63 are made common and simplified.

  When the output shaft of the drive motor 73 is rotationally driven by a predetermined amount, the feed roller 62 and the take-up roller 63 are rotated by a certain amount as described above, and the web sheet 61 is fed by a certain amount, and the nip region The web sheet 61 part is renewed.

  FIG. 3A shows a state before the web sheet 61 is used. The web sheet 61 is entirely wound around the feed roller 62, and the leading end of the web sheet 61 is connected to the winding roller 63. 63 is empty or nearly empty.

  When all the web sheets 61 of the feed roller 62 are fed, the feed roller 62 becomes empty or nearly empty as shown in FIG. 3B, and all the web sheets 61 are taken up by the take-up roller 63.

  In both the feed roller 62 and the take-up roller 63, when a sufficient amount of the web sheet 61 is wound, the strength of the entire roller is high and the roller hardly bends. On the contrary, in the state of being near or empty, the strength of the entire roller is lowered, so that the roller is easily bent.

  If the feed roller 62 and the take-up roller 63 are separately rotationally driven and the amount of rotation of each of the rollers 62 and 63 is appropriately controlled, no overload acts on any of the rollers. There is no need for bending of the roller.

  However, when the rotation driving mechanism of the feed roller 62 and the take-up roller 63 is shared, and the feed roller 62 and the take-up roller 63 are rotated synchronously, a load interacts between the rollers 62 and 63 and the web sheet 61. However, this load may become an overload for one of the rollers in an empty state or an almost empty state, and this one roller may bend. This causes wrinkles and overload of the web sheet 61, and the web sheet 61. Breaking or meandering occurs.

  Therefore, in the present embodiment, the rotational loads acting on the feeding roller 62 and the take-up roller 63 are controlled by the rotational load control units 71 and 72 shown in FIG. The roller is prevented from being overloaded to prevent the roller from bending.

  FIG. 4A is a cross-sectional view showing the rotational load control units 71 and 72. Each rotational load control unit 71, 72 includes a shaft support member 76, a boss 78, a spring 77, and a brake member 79.

  The feed roller 62 and the take-up roller 63 are hollow pipes, and their ends are rotatably supported by a boss 78 protruding from the inner recess 76a of the shaft support member 76.

  Here, the shaft support member 76 is supported by the main body of the image forming apparatus 100 so as to be movable along the rollers 62 and 63, and a spring 77 is disposed in the outer recessed portion 76 b of the shaft support member 76. The shaft support member 76 and the brake member 79 are urged toward the rollers 62 and 63 by 77. A disc ring-shaped brake member 79 is fixed to the end surface of the inner convex portion 76 c of the shaft support member 76.

  In the first period of use of the cleaning device 49, as shown in FIGS. 3A and 4A, a sufficient amount of the web sheet 61 is wound around the feed roller 62, and the take-up roller 63 is empty or nearly empty. It has become. At this time, on the feed roller 62 side, the shaft support member 76 and the brake member 79 are urged inward by the spring 77, and the brake member 79 is pressed against the laminated end surface 61 a of the web sheet 61 of the feed roller 62. The brake is applied to the delivery roller 62 by the contact between the brake member 79 and the laminated end surface 61 a of the web sheet 61, and a rotational load acts on the delivery roller 62. On the take-up roller 63 side, since the take-up roller 63 is empty or nearly empty, the brake member 79 is not pressed against the laminated end surface 61a of the web sheet 61, and the take-up roller 63 is braked. There is no such thing.

  Thus, in a state where the rotational load by the brake member 79 acts on the feeding roller 62, even if the feeding roller 62 and the take-up roller 63 rotate synchronously and the web sheet 61 is fed, The load that interacts between the web sheets 61 is reduced, and the rotational load of the take-up roller 63 is kept low. For this reason, even if the winding roller 63 is empty or nearly empty, the web sheet 61 does not bend, does not wrinkle or overload, and the web sheet 61 does not break or meander.

  Further, in the latter period of use of the cleaning device 49, as shown in FIGS. 3B and 4B, a sufficient amount of the web sheet 61 is wound around the take-up roller 63, and the feed roller 62 becomes substantially empty. Yes. Therefore, on the take-up roller 63 side, the shaft support member 76 and the brake member 79 are urged inward by the spring 77, and the brake member 79 is pressed against the laminated end surface 61 a of the web sheet 61 of the take-up roller 63. The take-up roller 63 is braked, and a rotational load acts on the take-up roller 63. On the delivery roller 62 side, since the delivery roller 62 is substantially empty, no brake is applied.

  Thus, in a state where the rotational load by the brake member 79 is applied to the take-up roller 63, even if the feed roller 62 and the take-up roller 63 rotate synchronously and the web sheet 61 is sent, the rotation of the feed roller 62 is increased. The load can be kept low. For this reason, even if the feeding roller 62 is empty or nearly empty, the web sheet 61 does not bend, does not wrinkle or overload, and the web sheet 61 does not break or meander.

  In the middle period of use of the cleaning device 49, the winding amount of the web sheet 61 is medium for both the feed roller 62 and the take-up roller 63, and is wound around the brake member 79 and the roller of the shaft support member 76. Further, the contact area between the laminated end surfaces 61a of the web sheet 61 is reduced, and the brake is hardly applied to the roller. However, the roller does not bend because the strength of the entire roller is high.

  As described above, in this embodiment, although the rotation drive mechanism of the feed roller 62 and the take-up roller 63 is shared, the brake member 79 brakes a roller around which a sufficient amount of the web sheet 61 is wound. The rotational load of the roller in the empty or near empty state is reduced, and the roller in the empty or near empty state is not bent, and the web sheet 61 can be prevented from being broken or meandered.

  Next, a second embodiment of the cleaning device of the present invention will be described.

  FIG. 5 is a side view schematically showing the cleaning device of the present embodiment. The cleaning device 49A of the present embodiment is applied to the fixing device 27 of FIG. 2 similarly to the cleaning device 49, and includes a feed roller 62, a take-up roller 63, a plurality of tension rollers 64, and a pressure roller 65. However, the arrangement positions of these rollers are different. Further, the rotation driving mechanism of the delivery roller 62 and the take-up roller 63 is shared, but the delivery roller 62 and the take-up roller 63 are rotated in opposite directions. Therefore, the rotation drive mechanism omits the transmission gear 75 of the rotation drive mechanism shown in FIGS. 3A and 3B, and directly connects the drive gear 68 of the take-up roller 63 and the drive gear 67 of the feed roller 62. The combined structure. Further, the brake member 79 on the take-up roller 63 side shown in FIGS. 3A and 3B is omitted, and only the brake member 79 on the feed roller 62 side is left.

  In the first period of use of the cleaning device 49 having such a configuration, since a sufficient amount of the web sheet 61 is wound around the feed roller 62 as shown in FIG. 5, the brake member 79 is provided on the feed roller 62 side. 62 is pressed against the laminated end surface 61 a of the web sheet 61, the delivery roller 62 is braked, and a rotational load acts on the delivery roller 62. On the winding roller 63 side, since the winding roller 63 is empty or nearly empty, the winding roller 63 is not braked.

  As described above, in a state where the rotational load by the brake member 79 is applied to the feeding roller 62, even if the feeding roller 62 and the winding roller 63 rotate synchronously and the web sheet 61 is fed, the winding roller 63 rotates. The load can be kept low. For this reason, even if the winding roller 63 is empty or nearly empty, the web sheet 61 does not bend and the web sheet 61 does not break or meander. In addition, although the torque of the take-up roller 63 is small, the take-up roller 63 is empty or nearly empty, so that even if the torque is not large, the take-up roller 63 takes up the web sheet 61. There is nothing.

  Further, in the latter stage of use of the cleaning device 49, as shown in FIG. 6, the feed roller 62 is empty or nearly empty, and the brake member 79 is not pressed against the laminated end surface 61a of the web sheet 61, and the feed roller No brake is applied to 62.

  In this state, since the strength of the entire take-up roller 63 is increased, the take-up roller 63 does not bend even if the feed roller 62 is not braked. Further, the torque of the take-up roller 63 is increased, and the web sheet 61 can be reliably taken up by the take-up roller 63.

  In addition, this invention is not limited to said each embodiment, It can deform | transform variously. For example, the time when the brake is applied to the feed roller 62 or the take-up roller 63 may be adjusted by changing the area and arrangement range of the brake member 79. In addition, the cleaning device of the present invention may be used not only for removing the heat roller of the fixing device but also the dirt of the pressure roller and rollers of other devices.

1 is a schematic view showing an image forming apparatus to which a first embodiment of a cleaning device of the present invention is applied. FIG. 2 is a cross-sectional view schematically showing a fixing device in the image forming apparatus of FIG. 1 when viewed from the side. (A), (b) is a top view which shows roughly the sending-out roller and winding roller periphery in the cleaning apparatus of 1st Embodiment. (A), (b) is sectional drawing which shows the rotational load control part for controlling the rotational load of the sending roller of FIG. 3, and a winding roller. It is a side view which shows schematically 2nd Embodiment of the cleaning apparatus of this invention. FIG. 6 is a side view showing a state in which the feed roller in the cleaning device of FIG. 5 is substantially empty.

Explanation of symbols

21 Photosensitive drum 22 Charger 23 Optical writing unit 24 Developing unit 25 Transfer unit 26 Cleaning unit 27 Fixing unit 35 Heating roller 36 Pressure roller 37 Peeling claw 41 Conveying roller 42 Registration roller 49 Cleaning device 61 Pickup rollers 71 and 72 Rotating load Control unit 100 Image forming apparatus 101 Document paper transport unit 102 Image reading unit 103 Printing unit 104 Recording paper transport unit 105 Paper feed unit

Claims (4)

A web roller is wound around the web sheet, and a web roller is connected to one end of the web sheet. The web sheet is fed from the web roller and wound on the wind roller. In a cleaning device using a web sheet that is brought into contact with another roller to remove deposits on the other roller,
Rotational load control for controlling the rotational load acting on the feed roller or the take-up roller in the process of decreasing the web roll amount of the feed roller and increasing the web roll of the take-up roller A cleaning device using a web sheet, characterized by comprising means.   The rotational load control means is a friction member that contacts an end surface of a web sheet layer wound around the feed roller, or a friction member that contacts an end surface of a web sheet layer wound around the winding roller. A cleaning device using the web sheet according to claim 1.   The friction member in contact with the end surface of the web sheet layer wound around the feed roller controls a rotational load acting on the feed roller or the take-up roller in the first period of use of the web sheet. A cleaning device using the described web sheet.   The friction member in contact with the end surface of the web sheet layer wound up by the winding roller controls a rotational load acting on the feeding roller or the winding roller in a later stage of use of the web sheet. A cleaning device using the web sheet according to 2.

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