JP6951678B2 - Fixing device and image forming device - Google Patents

Description

The present invention relates to a fixing device and an image forming device.

Conventionally, a fixing member that comes into contact with a surface of a recording medium on which an unfixed image is formed to fix the unfixed image, a heating means for heating the fixing member, and a pressure member that forms a fixing nip between the fixing member. And a fixing device including a pressure cleaning means for cleaning the surface of the pressure member is known.
As this type of fixing device, Patent Document 1 describes a configuration in which a cooling mechanism for cooling the surface of the pressure member at the time of fixing is provided to prevent the surface temperature of the pressure member from rising and a hot offset image from being generated. Has been done.

However, the configuration is not limited to the configuration provided with the cooling mechanism, and if the surface of the pressurizing member is lower than the temperature at which the image forming substance is melted at the time of fixing, image formation of toner or the like adhering to the surface of the pressurizing member is formed. The temperature of the substance dropped and the molten state could not be maintained, and the substance sometimes stuck to the surface of the pressure member. It is difficult to remove the image-forming substance that has adhered due to the temperature drop from the pressure member, and even if the image-forming substance is cleaned by the pressure cleaning means, there may be a problem that the image-forming substance remains attached to the surface of the pressure member. rice field.

In order to solve the above-mentioned problems, the present invention includes a fixing member that contacts the surface of the recording medium on which the unfixed image is formed to fix the unfixed image, and a fixing heating means for heating the fixing member. In a fixing device provided with a pressure member for forming a fixing nip that sandwiches the recording medium between the fixing member and a pressure cleaning means for cleaning the surface of the pressure member, the unfixed image is fixed. after the fixing operation performed, that the surface temperature of the pressing member is heated to a high temperature than when the fixing operation is performed after fixing the pressure member heated cleaning operation for cleaning by the pressurized cleaning means The pressure cleaning means is a cleaning member moving mechanism that moves the band-shaped cleaning member in contact with the pressure member and the band-shaped cleaning member so that the points of contact with the pressure member in the band-shaped cleaning member are different. It is characterized in that the movement amount of the strip-shaped cleaning member by the cleaning member moving mechanism is changed based on the information of the recording medium.

According to the present invention, there is an excellent effect that it is possible to prevent the image forming substance from being left attached to the surface of the pressure member.

The schematic block diagram of the fixing device which concerns on embodiment. The schematic block diagram of the printer which concerns on embodiment. A drawing comparing the case where the hardness of the pressure roller is higher than the case where the hardness of the pressure roller is lower than that of the fixing roller. The block diagram of the structure which controls the heating and cleaning operation of a pressurizing member after fixing. The flowchart which performs the pressure member heating cleaning operation after fixing. The flowchart of another example which performs the pressurizing member heating cleaning operation after fixing.

Hereinafter, an embodiment of an electrophotographic printer will be described as an image forming apparatus to which the present invention is applied.
FIG. 2 is a schematic configuration diagram showing the printer 100 according to the embodiment. As shown in FIG. 2, the printer 100 is an image forming unit 110 that forms a toner image on a paper P that is a recording medium, and a fixing device that fixes a toner image on the paper P on which a toner image is formed by the image forming unit 110. 40 and a paper feeding unit 120 for supplying the paper P to the image forming unit 110.

The image forming unit 110 has four image forming units 2 (Y, M, C, K) for forming a toner image of yellow (Y), magenta (M), cyan (C), and black (K). I have. The four image-forming units 2 are arranged side by side with respect to the intermediate transfer belt 61, which is an image-carrying belt, along the endless movement direction, which is a so-called tandem type configuration.

Further, the printer 100 includes a paper feed path 30, a pre-transfer transfer path 31, a manual feed path 32, a manual feed tray 33, a resist roller pair 34, a transfer belt unit 35, a transfer switching device 50, a paper discharge path 51, and a paper discharge roller. It is provided with a pair of 52 sheets, a paper output tray 53, and the like. The image forming unit 110 includes two optical writing units 1 (YM, CK), a primary transfer unit 60, a secondary transfer unit 78, and the like, and the paper feed unit 120 includes a first paper cassette 101 and a second feed. A paper cassette 102 or the like is provided.

The four image forming units 2 (Y, M, C, K) each have a drum-shaped photoconductor 3 (Y, M, C, K) which is a latent image carrier. Further, each of the first paper cassette 101 and the second paper cassette 102 houses a bundle of paper P which is a recording medium. Then, by rotationally driving the first feeding roller 101a or the second feeding roller 102a, the topmost paper P in the bundle of paper P is sent out toward the paper feed path 30.

On the right side surface of the housing of the printer 100 in FIG. 2, a manual feed tray 33 is arranged so as to be openable and closable with respect to the housing, and a bundle of paper P is placed on the upper surface of the tray in a state of being open with respect to the housing. It will be handed. The topmost paper P in the bundle of manually fed paper P is conveyed toward the paper feed path 30 via the manual feed feed path 32 by the delivery roller of the manual feed tray 33.

The two optical writing units 1 (YM, CK) each have a laser diode, a polygon mirror, various lenses, and the like. Then, based on the image information read by the scanner, which is an external device of the printer 100, and the image information sent from the personal computer, the laser diode is driven to drive the image forming unit 2 (Y, M, C, K). Photoreceptor 3 (Y, M, C, K) of Specifically, the photoconductors 3 (Y, M, C, K) of the image forming unit 2 (Y, M, C, K) are rotationally driven in the counterclockwise direction in FIG. 2 by the driving means. ..

The first optical writing unit 1YM performs an optical scanning process by irradiating the driving yellow photoconductor 3Y and magenta photoconductor 3M with laser light while deflecting them in the direction of the rotation axis. As a result, an electrostatic latent image based on the yellow image information and the magenta image information is formed on the yellow photoconductor 3Y and the magenta photoconductor 3M, respectively.
The second optical writing unit 1CK performs an optical scanning process by irradiating the driving cyan photoconductor 3C and the black photoconductor 3K with laser light while being deflected in the direction of the rotation axis. As a result, an electrostatic latent image based on the cyan image information and the black image information is formed on the cyan photoconductor 3C and the black photoconductor 3K, respectively.

The image forming unit 2 (Y, M, C, K) is a common support in which the photoconductor 3 (Y, M, C, K) and various devices arranged around the photoconductor 3 (Y, M, C, K) are used as one unit. They are integrally attached to and detached from the housing of the printer 100 while being supported by the printer 100. The four image forming units 2 (Y, M, C, K) have the same configuration except that the colors of the toners used are different from each other. Therefore, in the following description, "Y, M, C, K" indicating the color of the toner to be used will be omitted as appropriate.

In addition to the photoconductor 3, the image forming unit 2 has a developing device 4 for developing an electrostatic latent image formed on the surface of the photoconductor 3 into a toner image. Further, it has a charging device 5 that uniformly charges the surface of the photoconductor 3 that is driven to rotate. Further, it also has a drum cleaning device 6 for cleaning the transfer residual toner adhering to the surface of the photoconductor 3 after passing through the primary transfer nip corresponding to each color.

The photoconductor 3 is a drum-shaped body in which a photosensitive layer is formed by applying a photosensitive organic photosensitive material on a raw tube such as aluminum. Instead of the drum-shaped one, an endless belt-shaped one may be used.

The developing device 4 includes a rotatable developing sleeve made of a non-magnetic pipe, and a magnet roller arranged in the hollow of the developing sleeve so as not to rotate with respect to the sleeve. Then, an electrostatic latent image on the photoconductor 3 is formed by a two-component developer (hereinafter, simply referred to as a developer) containing a magnetic carrier supported on the surface of the developing sleeve by the magnetic force generated by the magnet roller and non-magnetic toners of each color. To develop.

To the developing device 4 (Y, M, C, K) of each color, the toner of each color in the toner bottle 103 (Y, M, C, K) of each color is appropriately replenished by the toner replenishing device of each color. A toner concentration sensor as a toner concentration detecting means is provided in the developing device 4. The toner concentration sensor detects the magnetic permeability of the developer due to the carrier, which is a magnetic material. The control unit of the printer 100 controls the drive of the toner replenishing device for each color based on the comparison between the output value from the toner density sensor of each color and the output target value from the sensor which is the toner concentration target value. As a result, the toner concentration of the developer is kept within a certain range (for example, 4 [wt%] to 9 [wt%]).

The drum cleaning device 6 is of a type in which the transfer residual toner is scraped from the surface of the photoconductor 3 by a cleaning blade made of polyurethane rubber which is brought into contact with the photoconductor 3. Instead of such a method, another method may be used. In the drum cleaning device 6, in addition to the cleaning blade, a rotatable fur brush is also brought into contact with the photoconductor 3 for the purpose of improving the cleanability. This fur brush also has a role of applying the lubricant to the surface of the photoconductor 3 while scraping the lubricant from the solid lubricant to make a fine powder.

A static elimination lamp is arranged above the photoconductor 3, and this static elimination lamp is also a part of the image forming unit 2. The static elimination lamp eliminates static electricity by irradiating the surface of the photoconductor 3 after passing through the portion facing the drum cleaning device 6. The surface of the statically eliminated photoconductor 3 is uniformly charged by the charging device 5, and then subjected to optical scanning by the above-mentioned optical writing unit 1. The charging device 5 is rotationally driven while receiving a charging bias from a power source. Instead of such a method, a scorotron charger type that performs a non-contact charging treatment on the photoconductor 3 may be adopted.

A primary transfer unit 60 is arranged below the four image forming units 2 (Y, M, C, K). The primary transfer unit 60 includes an intermediate transfer belt 61 which is an image carrier stretched by a plurality of rollers (63, 67, 68, 69 and 71). Then, while the intermediate transfer belt 61 is brought into contact with the photoconductor 3 (Y, M, C, K), it is endless in the clockwise direction (arrow “A” direction) in FIG. 2 by the rotational drive of any one roller. Move. As a result, a primary transfer nip for each color (Y, M, C, K) in which the photoconductor 3 (Y, M, C, K) and the intermediate transfer belt 61 abut is formed.

In the vicinity of the primary transfer nip for each color, the intermediate transfer belt 61 is attached to the photoconductor 3 (Y, M, C, K) by the primary transfer roller 62 (Y, M, C, K) arranged inside the belt loop. Press toward. A primary transfer bias is applied to each of the four primary transfer rollers 62 (Y, M, C, K) by the primary transfer power supply. As a result, a primary transfer electric field is formed in the primary transfer nip for each color to electrostatically move the toner image on the photoconductor 3 (Y, M, C, K) toward the intermediate transfer belt 61.

On the front surface of the intermediate transfer belt 61, which sequentially passes through the primary transfer nips for each color as the intermediate transfer belt 61 moves endlessly in the clockwise direction in FIG. 2, a Y toner image and an M toner image, The C toner image and the K toner image are sequentially superimposed and primary transferred. By this superposition primary transfer, a four-color superposition toner image is formed on the front surface of the intermediate transfer belt 61.

A secondary transfer unit 78 is arranged below the intermediate transfer belt 61 in FIG. The secondary transfer unit 78 includes an endless secondary transfer belt 77, a ground driven roller 72, a secondary transfer drive roller 79, a secondary belt cleaning device 76, a toner adhesion amount detection sensor 64, and the like. The secondary transfer belt 77 is tensioned by the ground driven roller 72 arranged inside the loop and the secondary transfer drive roller 79, and is shown in FIG. 2 as the secondary transfer drive roller 79 is rotationally driven. Is moved endlessly in the counterclockwise direction (arrow "B" direction).

The secondary transfer belt 77 of the secondary transfer unit 78 has its own grounding driven roller 72 hung with the secondary transfer bias roller 68 in the intermediate transfer belt 61 of the primary transfer unit 60. It forms a secondary transfer nip. The secondary transfer bias output from the secondary transfer power supply is applied to the secondary transfer bias roller 68 inside the loop of the intermediate transfer belt 61, whereas the ground driven roller 72 inside the loop of the secondary transfer belt 77 It is grounded. As a result, a secondary transfer electric field is formed in the secondary transfer nip.

A resist roller pair 34 is arranged on the right side of FIG. 2 of the secondary transfer nip, and the timing at which the paper P sandwiched between the rollers can be synchronized with the four-color superimposed toner image on the intermediate transfer belt 61. Send it to the secondary transfer nip. In the secondary transfer nip, the four-color toner image on the intermediate transfer belt 61 is collectively secondary-transferred to the paper P due to the influence of the secondary transfer electric field and the nip pressure, and is combined with the white color of the paper P to form a full-color image.

The secondary transfer residual toner adheres to the front surface of the intermediate transfer belt 61 after passing through the secondary transfer nip. The secondary transfer residual toner is removed from the surface of the intermediate transfer belt 61 by the intermediate transfer belt cleaning device 75 of the primary transfer unit 60.

The paper P that has passed through the secondary transfer nip is separated from the intermediate transfer belt 61 and the secondary transfer belt 77 and delivered to the transfer belt unit 35. The transport belt unit 35 stretches the endless transport belt 36 by the transport drive roller 37 and the transport driven roller 38, and is driven by the rotation of the transport drive roller 37 in the counterclockwise direction (arrow “C” in FIG. 2). It is moved endlessly in the "direction). Then, while holding the paper P delivered from the secondary transfer nip on the upper tensioning surface of the transport belt 36, the paper P is transported along with the endless movement of the transport belt 36, and the paper P is delivered to the fixing device 40.

The paper P sent into the fixing device 40 is sandwiched between the fixing nip N formed by the contact between the endless fixing belt 41 and the pressure roller 44. Then, the toner image is fixed on the surface by the action of pressurization or heating.

The paper P in which the toner image is transferred to the first surface by the secondary transfer nip and the toner image is fixed on the first surface by the fixing device 40 is sent out to the transfer switching device 50. In the printer 100, the retransmission means is configured by the transfer switching device 50, the retransmission path 54, the switchback path 55, the transfer path 56 after switchback, and the like. The transport switching device 50 switches the subsequent transport destination of the paper P received from the fixing device 40 between the paper discharge path 51 and the retransmission path 54.

Specifically, when executing a print job in the single-sided mode in which an image is formed only on the first surface of the paper P, the transport destination is set to the output path 51. As a result, the paper P on which the image is formed only on the first surface is sent to the output roller pair 52 via the output path 51 and discharged onto the output tray 53 outside the machine. Further, when executing a print job in the double-sided mode in which images are formed on both sides of the paper P, when the paper P having the images fixed on both sides is received from the fixing device 40, the transfer destination is discharged. Set to road 51. As a result, the paper P on which the images are formed on both sides is discharged onto the output tray 53 outside the machine.

On the other hand, when the paper P in which the image is fixed only on the first side is received from the fixing device 40 at the time of executing the print job in the double-sided mode, the transport destination is set to the retransmission path 54. A switchback path 55 is connected to the retransmission path 54, and the paper P sent to the retransmission path 54 enters the switchback path 55. Then, when the entire region of the paper P in the transport direction enters the switchback path 55, the transport direction of the paper P is reversed and the paper P switches back.

In addition to the retransmission path 54, the switchback path 55 is connected to the transfer path 56 after the switchback, and the switched-back paper P enters the transfer path 56 after the switchback. At this time, the paper P is turned upside down. Then, the upside-down paper P is retransmitted to the secondary transfer nip via the transfer path 56 after switchback and the above-mentioned paper feed path 30. The paper P on which the toner image is also transferred to the second surface by the secondary transfer nip has the toner image fixed on the second surface via the fixing device 40, and then the transfer switching device 50 and the paper ejection path 51. Paper is ejected onto the output tray 53 via the output roller pair 52.

FIG. 1 is a schematic configuration diagram of the fixing device 40.
The fixing device 40 shown in FIG. 1 is a belt fixing type, and includes a fixing belt 41 as a fixing member that comes into contact with the surface on which the unfixed toner T of the paper P is supported. The fixing belt 41 is stretched between a fixing roller 42, which is a fixing belt driving roller, and a heating roller 43, which is a fixing belt driven roller.

The fixing drive means for inputting the rotational drive to the fixing roller 42 includes a fixing drive motor and a reduction gear train, and the reduction gear train is connected to a fixing input gear fixed to the rotating shaft of the fixing roller 42. Rotational drive is input from the fixing drive motor, and the fixing roller 42 is rotationally driven in the clockwise direction (arrow "D" direction) in FIG. 1, so that the fixing belt 41 is rotated in the clockwise direction in FIG. 1 (arrow "F"). Rotate in the direction).

The fixing belt 41 is an endless belt formed of a PI (polyimide) layer, and has an outer peripheral surface coated with an offset inhibitor such as a PFA (polytetrafluoroethylene) film.
The fixing device 40 includes a tension roller 46 that applies tension to the fixing belt 41. The tension roller 46 is formed of a cylindrical aluminum tube.

The fixing device 40 includes a heating roller 43 which is a heating member made of a rotating body that accommodates the fixing heater 45 which is a heating body in the internal space.
The fixing device 40 includes a pressure roller 44 as a pressure member below the fixing roller 42. The pressurizing roller 44 is provided so as to face the fixing roller 42 with the fixing belt 41 sandwiched between them, and the pressing mechanism 440 pressurizes the fixing roller 42 via the fixing belt 41.
The fixing roller 42 and the pressure roller 44 are rubber rollers arranged so as to face each other with the fixing belt 41 interposed therebetween. By pressurizing the pressure roller 44 toward the center of the fixing roller 42 via the fixing belt 41, a fixing nip N is formed between the pressure roller 44 and the fixing belt 41.

The fixing roller 42, the pressure roller 44, and the heating roller 43 are rotatably supported at both ends in the longitudinal direction (direction perpendicular to the paper surface in FIG. 1) of the housing 400 of the fixing device 40, and the fixing drive motor and the heater are supported. The lamp is fixedly held in the housing.

A fixing heater 45 as a heat source is provided inside the heating roller 43, and during the fixing operation, the heating roller 43 is heated by the fixing heater 45, and the fixing belt 41 is heated by the heating roller 43.
The fixing belt 41 rotates when the fixing roller 42 is rotationally driven, and the pressurizing roller 44 is rotated around the fixing belt 41 which is rotated by the rotational driving of the fixing roller 42, in the counterclockwise direction in FIG. 1 (arrow “E”). Rotate in the direction). At this time, the surface moving speed of the outer peripheral surface of the fixing belt 41 and the surface moving speed of the pressure roller 44 are the same.

The surface temperature of the fixing belt 41 is detected by a fixing temperature sensor 415 composed of a known temperature detecting element or the like, and the known temperature control unit sets the surface temperature of the fixing belt 41 to a predetermined temperature based on the output of the fixing temperature sensor 415. The fixing heater 45, which is a heat source, is controlled in this way. As the control of the fixing heater 45, ON / OFF control, PID control, or the like is used.
Further, as shown in FIG. 1, the fixing device 40 includes a pressure roller cleaning device 410 that cleans the surface of the pressure roller 44.
Further, the fixing device 40 includes a pressurized surface temperature sensor 445 that detects the surface temperature of the pressurized roller 44.

The paper P carrying the unfixed toner T is a fixing device as shown by an arrow “α” in FIG. 1 along the inlet guide plate 47 arranged on the upstream side in the transport direction of the paper P with respect to the fixing nip N. It is carried into 40. Then, the fixing belt 41 and the pressure roller 44 pass through the fixing nip N, which is a nip portion formed via the fixing belt 41.

The pressure roller 44 and the fixing belt 41, which rotate in opposite directions to each other, move on the surface in the same direction at the fixing nip N, and the paper P is sandwiched and conveyed. At this time, the unfixed toner T formed on the paper P by the fixing belt 41 controlled to a predetermined temperature is heated and melted. Further, the unfixed toner T on the paper P is fixed by pressurizing the paper P in the state where the unfixed toner T is melted by the fixing nip N.
The paper P that has passed through the fixing nip N is separated from the fixing belt 41 by the fixing separation plate 48 at the exit of the nip portion, and is arranged on the downstream side in the transport direction of the paper P with respect to the fixing nip N by the post-fixing transport roller pair 49. It is discharged to the outside of the fixing device 40. A paper ejection sensor 59 is arranged at the fixing outlet portion between the fixing nip N and the post-fixing transfer roller pair 49 to confirm that the paper P has passed at a predetermined timing.

The above is a schematic description of the fixing device 40 in the printer 100.
The paper P that has passed through the transfer roller pair 49 after fixing is sent out of the printer 100 main body through the transfer path and the paper discharge path 51 in the transfer switching device 50.

The pressurizing mechanism 440 rotatably holds the pressurizing roller shaft 44a, which is the core metal of the pressurizing roller 44, and has a pressurizing moving lever 442 that can rotate around the pressurizing moving shaft 443 and a pressurizing moving shaft. A pressure moving motor 441 for inputting a drive for rotating the 443 is provided. By driving the pressure moving motor 441 and rotating the pressure moving lever 442 fixed to the pressure moving shaft 443, the pressure roller 44 is brought into contact with and separated from the fixing roller 42 and the fixing belt 41.

The pressure roller cleaning device 410 includes a cleaning web 11, a web holding shaft 11b, a web winding shaft 11a, and a web contact roller 11c, which are strip-shaped cleaning members. One end of the cleaning web 11 is fixed to the web winding shaft 11a, the other end is fixed to the web holding shaft 11b, and the portion of the cleaning web 11 between the web winding shaft 11a and the web holding shaft 11b is a web contact roller. It is pressed against the surface of the pressure roller 44 by 11c.

The pressure roller cleaning device 410 includes a web contact / detachment mechanism for connecting / detaching the web contact roller 11c to / from the pressure roller 44. By bringing the web contact roller 11c into contact with the pressure roller 44, the cleaning web 11 hung around the web contact roller 11c can be brought into contact with the pressure roller 44. Further, by separating the web contact roller 11c from the pressure roller 44, the cleaning web 11 can be separated from the pressure roller 44.

The web winding shaft 11a is rotationally driven in the direction of the arrow “G1” in FIG. 1 to wind the cleaning web 11, and the portion used for cleaning in contact with the pressure roller 44 of the cleaning web 11 is shown in FIG. Moves in the direction of the arrow "G2", and the unused portion comes into contact with the pressure roller 44. The unused portion of the cleaning web 11 is wound around the web holding shaft 11b. Then, the cleaning web 11 is pulled by moving in the direction of the arrow "G2" in FIG. 1, the web holding shaft 11b is rotated in the direction of the arrow "G3" in FIG. 1, and the unused portion of the cleaning web 11 is removed. It is fed toward the contact portion with the pressure roller 44. By cleaning the surface of the pressure roller 44 with a cleaning means using the cleaning web 11 as such a cleaning member, it is possible to continue cleaning the pressure roller 44 using a portion of the cleaning member without deposits. It will be possible. Therefore, it is possible to maintain the cleanability on the surface of the pressure roller 44.

The fixing device 40 includes a cooling mechanism 450 that cools the surface of the pressure roller 44. The cooling mechanism 450 includes a blower 451 and a duct 452, and as shown by an arrow “H” in FIG. 1, the air outside the fixing device 40 is sucked by the blower 451 and the surface of the pressure roller 44 is sucked by the duct 452. Guide to the vicinity. As a result, the pressure roller 44 is air-cooled so that the surface temperature does not rise excessively. As the cooling mechanism 450, the same cooling mechanism as that used for air cooling by the blower described in Patent Document 1 can be used. Further, the configuration for cooling the pressure roller 44 is not limited to the one using a blower, and it is sufficient that the pressure roller 44 can be cooled. For example, a configuration using cooling fins and a configuration using a Pertier element described in Japanese Patent Application Laid-Open No. 2008-203558 can be adopted.

Here, the conventional fixing device will be described.
In recent years, high productivity and colorization of image forming apparatus have rapidly progressed, and many of them equipped with a double-sided printing mechanism have become widespread. Therefore, it is necessary to further advance the measures for high speed in the fixing device mounted on the image forming device. In recent years, there is known a fixing device in which a heating member for heating a recording medium is composed of a film-shaped belt member (fixing belt) stretched by a plurality of tension rollers.

In the fixing device using such a fixing belt, the fixing belt before entering the fixing nip is sufficiently heated in advance by a heater arranged in the tension roller. Then, in the fixing nip, the toner image is fixed to the recording medium by applying heat to the recording medium and the toner image from the heated fixing belt. Therefore, even if the fixing belt is deprived of heat by the recording paper during the fixing process, the heat capacity of the fixing belt itself is small, so that the fixing belt reaches a predetermined fixing temperature in a short time by the heater in the tension roller. It is possible to recover. As a result, in a fixing device using a fixing belt as a heating member, it becomes easy to maintain the temperature of the fixing belt when entering the nip portion at a predetermined value, and even if the speed of the image forming apparatus is increased, the nip portion is covered. It is possible to supply a sufficient amount of heat.

Further, in recent years, the demand for high-speed printing and envelope printing has been increasing, and in order to satisfy this demand, the pressure roller forming the fixing nip has been made elastic. By making the pressure roller elastic, it is possible to increase the nip width and form parallel nip, which makes it possible to reduce wrinkles.

However, by making the pressure roller elastic, the amount of thermal expansion of the elastic layer of the pressure roller increases as compared with the conventional case. Therefore, the shape of the pressure roller may not be the target, and in such a case, the transfer performance of the transfer paper at the fixing nip is deteriorated. As a configuration for suppressing such a defect, there is a configuration having an elastic pressure roller and having a cooling mechanism for lowering the temperature of the pressure roller, such as the fixing device described in Patent Document 1. With such a cooling mechanism, it is possible to suppress an increase in the surface temperature of the pressure roller when passing paper through the fixing nip, and to suppress an increase in the amount of thermal expansion of the elastic layer of the pressure roller.

Further, by thickening the elastic layer of the pressure roller, it becomes difficult to mount the heater inside the pressure roller. Therefore, in the configuration in which the elastic layer of the pressure roller is thickened, the only means for raising the temperature of the pressure roller is a method of propagating heat from the fixing belt to the pressure roller by the pressure operation on the fixing belt.

On the other hand, there is an increasing demand for higher image quality for copy images output by electrophotographic image forming apparatus. In order to ensure print quality, the trend is to reduce the diameter of the toner or make it spherical like a polymerized toner. Compared with conventional toner, such toner is less likely to transfer heat to the toner and is less likely to melt, so that low temperature offset is likely to occur. In particular, in the case of paper having irregularities on the paper surface such as uncoated paper, low temperature offset is likely to occur.

As a method of removing the deposits by the low temperature offset, there is a method of providing a cleaning means for wiping the surface of the member forming the fixing nip by pressing a cleaning web such as a non-woven fabric against the member forming the fixing nip.
In the fixing device that cleans the member forming the fixing nip with the cleaning web, a new part of the cleaning web is sent to the peripheral surface of the member forming the fixing nip to perform cleaning after each series of fixing jobs. Perform winding. As a result, the surface of the member to be cleaned can be wiped using the unused portion of the cleaning web, and the cleanability can be maintained and improved.

However, in the above-described configuration that keeps the surface temperature of the pressure roller low, the offset toner adhering to the pressure roller is in a fixed state without melting, and the toner in this state cannot be sufficiently cleaned. Was occurring.
Such a problem is not limited to a configuration in which the pressure roller does not have a heater or a configuration in which the pressure roller has a thick elastic layer, and the surface of the pressure roller becomes lower than the temperature at which the toner is melted at the time of fixing. If it is a configuration, it is a problem that can occur.

In the fixing device 40 of the present embodiment, after the fixing operation of fixing the unfixed toner T to the paper P, the surface temperature of the pressure roller 44 is heated to be higher than that of the fixing operation, and the pressure roller cleaning is performed. After fixing, the pressurizing member is heated and cleaned by the device 410.
By setting the surface temperature of the pressurizing roller 44 to be equal to or higher than the melting temperature of the toner in the pressurizing member heating and cleaning operation after fixing, the toner adhering to the pressurizing roller 44 is melted and easily removed by the pressurizing roller cleaning device 410. You will be able to. As a result, it is possible to prevent the toner from remaining attached to the surface of the pressure roller 44.

In the fixing device 40 of the present embodiment, the following control is executed as the heating and cleaning operation of the pressurizing member after fixing.
That is, the pressure roller 44 is not separated from the fixing belt 41 after the fixing operation is completed, which is after the printing operation of the printer 100 is completed, and the contact state is maintained for a predetermined time. Further, during this predetermined time, the contact state of the cleaning web 11 of the pressure roller cleaning device 410 with respect to the pressure roller 44 is also maintained. Further, during this predetermined time, the fixing belt 41 is continuously heated by the fixing heater 45.

In the post-fixing pressure member heating and cleaning operation, the pressure roller 44 can be heated by maintaining the contact state of the pressure roller 44 with the fixing belt 41 while the fixing belt 41 is heated by the fixing heater 45. can. By maintaining this contact state for a predetermined time, the surface temperature of the pressure roller 44 can be heated to be higher than that during the fixing operation, and the toner fixed to the pressure roller 44 can be melted. Further, by maintaining the contact state of the cleaning web 11 with the pressure roller 44, the molten toner can be removed by the cleaning web 11.

The pressurizing roller 44 of the fixing device 40 is a roller member having an outer diameter of 80 [mm], and has a structure in which a rubber elastic layer of 10 [mm] or more is provided on a cylindrical core metal having an outer diameter of 60 [mm] or less. Is. Further, a PFA layer is provided on the surface layer of the rubber elastic layer so that deposits such as paper P and toner can be easily released.
The pressure roller 44 is provided with an elastic layer having a hardness (shore hardness [Hs]) of 200 [%] or less (twice or less) with respect to the elastic layer of the fixing roller 42 on the core metal.

FIG. 3 is a drawing comparing the case where the hardness of the pressure roller 44 is higher than the case where the hardness of the pressure roller 44 is higher than that of the fixing roller 42.
When the hardness of the pressure roller 44 is too high with respect to the fixing roller 42, the pressure roller 44 is deeply sunk into the fixing roller 42, and as shown in FIG. 3A, the fixing nip N becomes convex upward. When the fixing nip N becomes convex upward, the length of the portion forming the nip of the fixing belt 41 becomes longer than the length of the portion forming the nip of the pressure roller 44, and the fixing belt 41 and the pressure roller 44 become There is a line speed difference between them. When this linear speed difference occurs, the paper P is wrinkled due to the linear speed difference between the fixing belt 41 that contacts the upper surface of the paper P passing through the fixing nip N and the pressure roller 44 that contacts the lower surface. Is likely to occur.

On the other hand, in the fixing device 40 of the present embodiment, both the fixing roller 42 and the pressure roller 44 have an elastic layer, and the condition that the hardness of the pressure roller 44 is 200 [%] or less of the hardness of the fixing roller 42 is satisfied. .. Therefore, by pressurizing the pressurizing roller 44 against the fixing roller 42, the two rollers are compressed with each other, and the fixing nip N becomes a parallel nip as shown in FIG. 3 (b). The parallel nip is a straight line in which both the upstream end and the downstream end of the nip are orthogonal to the surface movement direction of the pressure roller 44, and the straight line of the upstream end and the downstream end of the nip. Is a nip that is parallel to. Then, the shape of the nip is closer to a flat surface than the fixing nip N which is convex upward as shown in FIG. 3A.

In the fixing nip N which is a parallel nip, the length of the portion forming the nip of the fixing belt 41 and the length of the portion forming the nip of the pressure roller 44 are substantially the same, and between the fixing belt 41 and the pressure roller 44. It is possible to suppress the occurrence of a linear speed difference. Therefore, it is possible to suppress the occurrence of wrinkles on the paper P due to the difference in linear velocity.
Further, by making the pressure roller 44 elastic, the pressure roller 44 is easily deformed by an arbitrary pressing force, and the nip width (length in the surface moving direction) of the fixing nip N can be secured widely. can.

When the paper P is an envelope, a fixing nip N having a parallel nip and a wide nip width is required. In the fixing device 40 of the present embodiment, by satisfying the condition that the hardness of the pressure roller 44 is 200 [%] or less of the hardness of the fixing roller 42, a fixing nip N having a wide nip width can be formed by parallel nips, and the envelope can be formed. On the other hand, good fixing can be performed.

The pressure roller 44 of the present embodiment uses a material having a rubber hardness of 40 [Hs] as the elastic body forming the elastic layer, and forms a roller member having a hardness of 73 [Hs] as the pressure roller 44. .. Further, the fixing roller 42 used a material having a rubber hardness of 20 [Hs] as the elastic body forming the elastic layer, and formed a roller member having a hardness of 42 [Hs] as the fixing roller 42.

The fixing device 40 is an endless fixing belt stretched between a heating roller 43 having a fixing heater 45 as a heat source and a fixing roller 42 having an elastic layer on a metal core and having no heat source inside. 41 is provided. Further, a pressure roller 44 having an elastic layer having a hardness of 200 [%] or less with respect to the fixing roller 42 and having no heat source inside is pressed against the fixing roller 42 with the fixing belt 41 sandwiched between the metal cores. Is arranged. Further, the fixing device 40 includes a pressure mechanism 440 which is a contact / depressurization mechanism for pressurizing and depressurizing the fixing roller 42 and the pressure roller 44, a cooling mechanism 450 for cooling the pressure roller 44, and a surface of the pressure roller 44. Is provided with a pressure roller cleaning device 410 for sending and cleaning the cleaning web 11.

In the fixing device 40, in the post-fixing pressure member heating and cleaning operation after the fixing operation of passing the paper P through the fixing nip N, the pressure roller 44 is in contact with the fixing belt 41 and the cleaning web 11 is added. The state of being in contact with the pressure roller 44 is maintained. Then, in the heating and cleaning operation of the pressure member after fixing, the heating time for keeping the pressure roller 44 in contact with the fixing belt 41 in order to raise the temperature of the pressure roller 44 to a predetermined temperature is set for the brand of paper P or the like. Change according to the characteristics.

The fixing device 40 includes a pressurizing mechanism 440, and separates the pressurizing roller 44 from the fixing roller 42 when it is not necessary to bring the pressurizing roller 44 into contact with the fixing roller 42 across the fixing belt 41. As a result, the deformed state of the two rollers can be released by bringing the pressure roller 44 into contact with the fixing roller 42, and the life of the pressure roller 44 and the fixing roller 42 can be improved.

By having the pressure roller 44 of the fixing device 40 having a thick elastic layer of 10 [mm] or more, it is possible to form a parallel nip having a wide nip width as the fixing nip N. By securing a wide nip width, it is possible to prolong the time for the paper P to pass through the fixing nip N as compared with the one having a narrow nip width, and even in the printer 100 that performs high-speed printing, the time required for fixing. It becomes possible to secure the above, and it is possible to improve the fixability. Further, by forming the parallel nip, good fixing can be performed even when an envelope is used as the paper P.

In the case of a configuration having a thick elastic layer as the pressure roller 44, when a heat source is arranged inside the pressure roller 44 and the surface of the pressure roller 44 is heated to a desired temperature, the thick elastic layer is formed. The amount of deformation due to thermal expansion of is increased. In such a case, the nip width and shape of the fixing nip N may fluctuate depending on the deformed state of the elastic layer, which may cause variations in the fixing quality or deteriorate the transport performance of the paper P in the fixing nip N.
Further, when a drum-shaped roller member whose central portion in the axial direction has a larger outer diameter than both ends in the axial direction is used as the pressurizing roller 44, when the amount of deformation due to thermal expansion becomes large, the predetermined drum shape collapses and the fixing nip The uniformity of the nip pressure at N may be impaired.

On the other hand, the fixing device 40 heats the fixing belt 41 by a heating roller 43 having a fixing heater 45, and fixes the unfixed toner T on the surface of the paper P by the heat of the fixing belt 41. With such a configuration, it is possible to suppress deformation of the elastic layer of the pressure roller 44 due to thermal expansion, and to suppress fluctuations in the nip width and shape of the fixing nip N, thereby stabilizing the fixing quality and maintaining the transport performance. Can be planned.

The fixing device 40 includes a cooling mechanism 450, can prevent the surface temperature of the pressure roller 44 from rising excessively, and causes hot offset and toner blister due to the surface temperature of the pressure roller 44 being too high. It can be prevented and the deterioration of image quality can be prevented. Further, by preventing the surface temperature of the pressure roller 44 from rising excessively, it is possible to prevent the above-mentioned problems caused by the thermal expansion of the pressure roller 44.

The fixing device 40 includes a pressure roller cleaning device 410, and removes the offset toner adhering to the pressure roller 44 by the cleaning web 11. As the material of the cleaning web 11, a material that can be impregnated with oil for recovering the offset toner is used.
The pressure roller cleaning device 410 separates the cleaning web 11 from the pressure roller 44 by separating the web contact roller 11c from the pressure roller 44 by the web contact / disconnection mechanism.

When recovering the offset toner from the pressure roller 44, it is desirable that the toner is in a molten state on the surface of the pressure roller 44. However, the fixing device 40 of the present embodiment is provided with a cooling mechanism 450 as a configuration for preventing the occurrence of a defect caused by the surface temperature of the pressure roller 44 being too high, and the surface of the pressure roller 44 is cooled. There is. Therefore, on the surface of the pressure roller 44, the temperature of the offset toner drops and solidifies, and the toner tends to stick. It is difficult to remove the stuck toner, and even if the pressure roller cleaning device 410 tries to remove the toner, the toner tends to remain adhered to the surface of the pressure roller 44.
If the toner remains attached to the surface of the pressure roller 44, the lump of toner adhering to the surface of the pressure roller 44 becomes large with time, and if it is separated from the pressure roller 44 for some reason, the inside of the device is contaminated or the paper P It may cause problems such as stains on the back of the paper and black spots.

In the fixing device 40 of the present embodiment, after the fixing operation is completed, which is after the printing operation of the printer 100 is completed, the pressurizing member heating and cleaning operation is executed after the fixing, and the pressurizing is performed in a state where the surface temperature of the pressurizing roller 44 is raised. Cleaning is performed by the roller cleaning device 410. As a result, the toner that has melted on the surface of the pressure roller 44 and is in a state of being easily removed can be removed by the pressure roller cleaning device 410, and the toner remains attached to the surface of the pressure roller 44. Can be prevented. Therefore, it is possible to suppress the occurrence of problems caused by contamination inside the device, stains on the back of the paper P, and toner remaining adhering to the surface of the pressure roller 44 such as black spots.

The fixing device 40 of the present embodiment includes a cooling mechanism 450 that suppresses an increase in the surface temperature of the pressure roller 44, and cools the surface of the pressure roller 44 during the fixing operation. Further, by thickening the elastic layer of the pressure roller 44, it becomes difficult to mount a heating means such as a heater in the pressure roller 44. Therefore, the pressure roller 44 is brought into contact with the fixing belt 41 to raise the temperature of the pressure roller 44 during the heating and cleaning operation of the pressure member after fixing, and the heat generated from the fixing heater 45 causes the fixing belt 41 to come into contact with the fixing belt 41. A configuration is adopted in which the pressure is propagated to the pressure roller 44 via the pressurizing roller 44.

The configuration for heating the pressurizing roller 44 during the heating and cleaning operation of the pressurizing member after fixing is not limited to the configuration for indirectly heating the pressurizing roller 44 via the fixing belt 41. For example, a heating means for heating the outer peripheral surface of the pressure roller 44 may be provided separately from the fixing heater 45, or a heating means may be provided inside the pressure roller 44. In these configurations, the pressure roller 44 can be directly heated by the heating means after the printing is completed.

By configuring the pressurizing roller 44 to be pressurized by the heat of the fixing belt 41 as in the fixing device 40 of the present embodiment, it is not necessary to separately provide a heating means for heating the pressurizing roller 44, and the cost is reduced. Can be planned.

The operation of heating and cleaning the pressurizing member after fixing is a control for removing the offset toner adhering to the pressurizing roller 44, and it is desirable to execute the operation when the image is formed under the condition that the offset toner is easily adhered.
Conditions on which the offset toner easily adheres include the case where a toner having poor fixability is used, the case where the smoothness of the paper P is low, the case where an image such as a halftone image in which the toners are weakly bonded to each other is formed, and the like. can.

Hereinafter, as a condition that affects the likelihood of toner offset, it is determined whether or not the post-fixing pressurizing member heating and cleaning operation is necessary based on the type of paper P, and if necessary, the post-fixing pressurizing member heating and cleaning is performed. The control for executing the operation will be described.

FIG. 4 is a block diagram of a configuration for controlling the heating and cleaning operation of the pressurizing member after fixing.
The control unit 200 pressurizes after fixing based on parameters such as the type, basis weight, paper size, brand, and thickness of the paper P on which the image is formed, which is input from the operation panel 300 by the user. Judge the necessity of member heating and cleaning operation.

FIG. 5 is a flowchart in which the pressurizing member is heated and cleaned after fixing.
When the printing operation on the printer 100 is started, it is determined whether or not the printing operation is completed (S11). While the printing operation is not completed (“No” in S11), the fixing device 40 continues the normal fixing operation. When the printing operation is completed (“Yes” in S11), the control unit 200 acquires parameter information indicating the characteristics of the paper P that has been passed through during the printing operation (S12).

Next, it is determined whether or not the passed paper P is a paper type that is likely to cause offset, such as uncoated paper or paper having an uneven surface, and the integrated distance of the paper P that is likely to cause offset is the pressure member after fixing. It is determined whether or not it is equal to or higher than the threshold value for starting the heating and cleaning operation (S13). When the integrated distance of the paper P, which is likely to be offset, is less than the threshold value (“No” in S13), the pressurizing member is not heated and cleaned after fixing, and the pressurizing roller 44 is separated from the fixing roller 42 to pressurize the pressurizing roller. The cleaning web 11 is separated from 44 (S17), and the control is terminated.

When the integrated distance of the paper P, which is likely to be offset, is equal to or greater than the threshold value (“Yes” in S13), the pressurizing member heating and cleaning operation is started after fixing (S14). In the pressurizing member heating and cleaning operation after fixing, the surface temperature of the pressurizing roller 44 is detected by the pressurizing surface temperature sensor 445, and it is determined whether or not the target temperature has been reached (S15). When it is detected that the target temperature has been reached (“Yes” in S15), it is determined whether or not a predetermined heating time has elapsed since the printing operation was completed (S16). When it is detected that the heating time has elapsed (“Yes” in S16), the pressure roller 44 is separated from the fixing roller 42, the cleaning web 11 is separated from the pressure roller 44 (S17), and the control is terminated. ..

After reaching the target temperature in step "S15" shown in FIG. 5, the pressure roller 44 is kept in contact with the fixing belt 41 until the heating time elapses in step "S16". The temperature of 44 becomes even higher than the target temperature. Even if the pressure roller 44 is higher than the target temperature, the temperature is hardly too high because the purpose of the pressure member heating and cleaning operation after fixing is to melt the adhered toner. Further, since the control is performed after the paper is passed, that is, after the printing operation, the image quality is not affected. Further, since the pressure roller 44 is heated by the fixing belt 41, the temperature does not exceed the temperature of the fixing belt 41, and there is no problem in the thermal durability of the pressure roller 44.

Depending on the type of paper P, the offset toner adhering to the pressurizing roller 44 can be recovered while ensuring the image quality and the transport quality by executing the pressurizing member heating and cleaning operation after fixing after the printing operation is completed.

Further, the information of the passed paper P may be stored, and the heating time in the pressurizing member heating / cleaning operation after fixing may be changed according to the characteristics of the paper P such as smoothness based on the information. ..

Table 1 shows an example of a control table that changes the heating time according to the smoothness of the paper P. In the example shown in Table 1, the smaller the basis weight, the longer the heating time, and when the basis weight is the same, the heating time is longer in the case of non-coated paper where toner offset is likely to occur than in the case of coated paper. I do. By changing the heating time according to the characteristics of the paper P such as smoothness, it is possible to optimize the time for executing the pressurizing member heating and cleaning operation after fixing, and the downtime under the condition of the paper P where offset is unlikely to occur. Can be shortened.

As the heating and cleaning operation of the pressure member after fixing, the amount of contact of the cleaning web 11 with the pressure roller 44 may be changed according to the characteristics such as the brand of the paper P that has been passed by the end of the printing operation.

Table 2 shows an example of a control table that changes the amount of contact of the cleaning web 11 with respect to the pressure roller 44 according to the smoothness of the paper P. In Table 2, the larger the number of the web contact position, the larger the contact pressure of the cleaning web 11 with respect to the pressure roller 44. In the example shown in Table 2, in the case of uncoated paper in which toner offset is likely to occur, control is performed to increase the contact pressure of the cleaning web 11 with respect to the pressure roller 44.

By the control shown in Table 2, in the post-fixing pressurizing member heating and cleaning operation after printing on a type of paper P having low smoothness such as uneven paper and prone to toner offset, the cleaning web for the pressurizing roller 44 is performed. The contact pressure of 11 is increased to increase the recovery power of offset toner. On the contrary, in the post-fixing pressurizing member heating and cleaning operation after printing on a type of paper P having high smoothness and less toner offset such as coated paper, the contact pressure is lowered.

Bringing the cleaning web 11 into contact with the pressure roller 44 with a high contact pressure shortens the life of both the pressure roller 44 and the cleaning web 11. By the control shown in Table 2, it is possible to maintain an appropriate contact pressure according to the characteristics of the paper P. Specifically, under conditions where offset is likely to occur, the contact pressure is increased to obtain good cleaning performance, while under conditions where offset is unlikely to occur, the contact pressure is lowered to reduce the life of the pressurizing roller 44 and the cleaning web 11. Can be suppressed.

As the heating and cleaning operation of the pressurizing member after fixing, the target temperature of the surface of the pressurizing roller 44 may be changed according to the characteristics such as the brand of the paper P that has been passed through by the end of the printing operation.

Table 3 shows an example of a control table that changes the target temperature of the surface of the pressurizing roller 44 in the pressurizing member heating and cleaning operation after fixing according to the smoothness of the paper P. In the example shown in Table 3, the pressurizing roller 44 is maintained in the contact state after the printing operation is completed (during the pressurizing member heating and cleaning operation after fixing) according to the characteristics of the paper P such as smoothness. Set the target temperature for. Specifically, the smaller the basis weight, the higher the target temperature of the pressurizing roller 44, and when the basis weight is the same, the uneven paper or uncoated paper, which is prone to toner offset, is more likely than the coated paper. Control is performed to raise the target temperature of the pressurizing roller 44.

After passing the paper P on which toner offset is likely to occur, the target temperature is set high to melt the offset toner adhering to the pressure roller 44, and the recoverability is improved. On the other hand, after passing a coated paper or the like in which the toner is hard to adhere to the pressure roller 44, the target temperature is set low. As a result, the time required for the pressurizing roller 44 to reach the target temperature is shortened, the time for executing the pressurizing member heating and cleaning operation after fixing is optimized, and the downtime under the condition of paper P in which offset is unlikely to occur is achieved. Can be shortened.

In the fixing device 40 that performs the pressurizing member heating and cleaning operation after fixing, it is determined whether or not to execute the pressurizing member heating and cleaning operation after fixing according to the characteristics such as the brand of the paper P that has been passed by the end of the printing operation. It may be configured to change the threshold value.

Table 4 shows an example of a control table that changes the threshold value for determining whether or not to perform the pressurizing member heating and cleaning operation after fixing according to the smoothness of the paper P. In the example shown in Table 4, the threshold value is set according to the characteristics of the paper P such as smoothness. Specifically, the smaller the basis weight, the higher the threshold value for executing the pressurizing member heating and cleaning operation after fixing. In addition, when the basis weight is the same, in the case of uneven paper or uncoated paper where toner offset is likely to occur, the threshold value for determining whether to perform the pressurizing member heating and cleaning operation after fixing is set as compared with the case of coated paper. Control to make it smaller.

In the fixing device 40, the trigger for whether or not the pressurizing member heating and cleaning operation can be executed after fixing is the number of sheets to be passed or the passing time, and the threshold value is set according to the characteristics of the paper P. For example, the threshold value is set small under conditions such as uneven paper and uncoated paper where toner offset is likely to occur, and the threshold value is set large under conditions such as coated paper where toner offset is unlikely to occur. When paper that is prone to toner offset is passed through, the pressurizing member is frequently heated and cleaned after fixing to maintain image quality. When paper is passed through which toner offset is unlikely to occur, the effect on the life of the member can be reduced by increasing the interval for executing the pressurizing member heating and cleaning operation after fixing.

The fixing device 40 that performs the pressurizing member heating and cleaning operation after fixing may have a configuration in which the amount of winding of the cleaning web 11 is changed according to the characteristics such as the brand of the paper P that has been passed by the end of the printing operation.

Table 5 shows an example of a control table that changes the winding amount of the cleaning web 11 in the pressurizing member heating and cleaning operation after fixing according to the smoothness of the paper P. In the example shown in Table 5, the smaller the basis weight of the paper P, the larger the winding amount of the cleaning web 11, and when the basis weight is the same, the paper is coated in the case of uneven paper or uncoated paper in which toner offset is likely to occur. Control is performed to increase the winding amount of the cleaning web 11 as compared with the case of paper.

The pressure roller cleaning device 410 drives the web take-up motor and rotates the web take-up shaft 11a when the integrated value of the print rate of the image formed on the paper P that has passed through the fixing nip N becomes equal to or higher than the threshold value. Drive to wind up the cleaning web 11. As a result, the unused portion of the cleaning web 11 is brought into contact with the pressure roller 44. If the amount of winding is smaller than that of the offset toner to be collected, the offset toner that has failed to be collected is returned to the pressure roller 44 again, which causes an abnormal image. For example, when uneven paper or uncoated paper is passed through, the amount of offset toner collected by executing the pressurizing member heating and cleaning operation after fixing increases. In such a case, by increasing the winding amount of the cleaning web 11, the offset toner can be sequentially collected on a new surface, and good cleaning performance can be maintained. On the other hand, when a paper having a relatively small amount of offset toner to be collected, such as coated paper, is passed through the paper, the winding amount is reduced in order to extend the life of the cleaning web 11.

In the fixing device 40 that performs the pressurizing member heating and cleaning operation after fixing, the target temperature on the surface of the fixing belt 41 may be changed according to the characteristics such as the brand of the paper P that has been passed by the end of the printing operation.

Table 6 shows an example of a control table that changes the target temperature of the fixing belt 41 in the pressurizing member heating and cleaning operation after fixing according to the smoothness of the paper P. In the example shown in Table 6, the target temperature of the fixing belt 41 is raised as the basis weight is smaller, and when the basis weight is the same, the case of uneven paper or uncoated paper in which toner offset is likely to occur is higher than that of coated paper. Also controls to raise the target temperature of the fixing belt 41.

By changing the target temperature of the fixing belt 41 according to the characteristics of the passed paper P, the time until the pressure roller 44 on the side receiving heat from the fixing belt 41 reaches the target temperature is shortened, and after fixing. The downtime due to the heating and cleaning operation of the pressurizing member can be shortened. For example, when paper with irregularities or uncoated paper, which is relatively prone to toner offset, is passed through, it is fixed by setting a high target temperature of the fixing belt 41 in the heating and cleaning operation of the pressurizing member after fixing. The heat transfer from the belt 41 to the pressure roller 44 can be accelerated.

Further, the pressure roller cleaning device 410 of the fixing device 40 of the present embodiment is provided with a web contact / detachment mechanism, and has a configuration capable of pressurizing and depressurizing the cleaning web 11 with respect to the pressure roller 44. Therefore, the offset toner can be recovered more efficiently by storing the printing conditions such as the information of the printed paper P and the information of the printed image and executing the optimum cleaning operation according to the stored printing conditions. Is possible.
Further, since the pressure member heating and cleaning operation after fixing controls to raise the temperature of the pressure roller 44 after passing the paper, it is possible to suppress the pressure roller 44 from being deformed by heat before passing the paper, and the pressure roller 44 passes through the fixing nip N. It is possible to pass the paper without giving stress to the paper P. Therefore, the transport performance of the fixing device 40 can be improved.

FIG. 6 is a flowchart of another example in which the pressurizing member is heated and cleaned after fixing.
When the printing operation on the printer 100 is started, it is determined whether or not the printing operation is completed (S21). While the printing operation is not completed (“No” in S21), the fixing device 40 continues the normal fixing operation. When the printing operation is completed (“Yes” in S21), the control unit 200 acquires parameter information indicating the characteristics of the paper P that has been passed through during the printing operation (S22).

Next, it is determined whether or not the passed paper P is a paper type in which offset is likely to occur, such as uncoated paper or paper having an uneven surface, and after the integrated distance of the passed paper of the paper P in which offset is likely to occur is fixed. It is determined whether or not it is equal to or higher than the threshold value for starting the pressurizing member heating and cleaning operation (S23). When the integrated distance of the paper P on which the offset is likely to occur is less than the threshold value (“No” in S23), the pressure roller 44 is separated from the fixing roller 42, and the cleaning web 11 is separated from the pressure roller 44 (S26). , End control.

A threshold value is set for the integrated distance of the paper P that is likely to be offset, and when the integrated distance of the paper P that is likely to be offset is equal to or greater than the threshold value (“Yes” in S23), the pressurizing member heating and cleaning operation is started after fixing. (S24). In the post-fixing pressurizing member heating and cleaning operation, the contact state is maintained until a predetermined contact maintenance time elapses after the paper is passed. As a result, the pressure roller 44 can be heated until the contact maintenance time elapses. After the predetermined contact maintenance time has elapsed (“Yes” in S25), the pressure roller 44 is separated from the fixing roller 42, the cleaning web 11 is separated from the pressure roller 44 (S26), and the control is terminated. do.

In the control configuration shown in FIG. 5, the contact state of the pressure roller 44 with respect to the fixing belt 41 and the contact state of the cleaning web 11 with respect to the pressure roller 44 are maintained after the paper is passed. Further, when the contact maintenance time for maintaining this contact state and the threshold value for the integrated distance of the paper passing are set in advance and the integrated distance of the paper passing paper P, which is likely to be offset, becomes equal to or more than the threshold value. In addition, after passing the paper, the above-mentioned contact state is maintained until the contact maintenance time elapses.

Depending on the characteristics of the passed paper P, it is determined whether or not to perform the pressurizing member heating and cleaning operation after fixing, and the contact maintenance time when performing the pressurizing member heating and cleaning operation after fixing is changed. Or something. As a result, the timing for collecting the offset toner adhering to the pressurizing roller 44 is optimized due to the characteristics of the passed paper P, and the downtime due to the pressurizing member heating and cleaning operation being repeatedly executed more than necessary after fixing. Can be shortened.

The control content of the pressurizing member heating and cleaning operation after fixing by the fixing device 40 may be selected for each paper type paper thickness or for each paper brand. For example, after passing the paper P, which has low smoothness such as uneven paper and is prone to toner offset, the pressurizing member is heated and cleaned after fixing to increase the recovery power of the offset toner. On the contrary, after passing the paper P having high smoothness and less toner offset such as coated paper, the pressurizing member heating and cleaning operation is not executed after fixing. As a result, it is possible to suppress the occurrence of downtime due to the pressure member heating and cleaning operation being executed after the paper P, in which toner offset is unlikely to occur, is passed.

An example of the control table is shown in Table 7. “0” in Table 7 is a control that does not execute the pressurizing member heating / cleaning operation after fixing, and “1” in Table 7 is a control that executes the pressurizing member heating / cleaning operation after fixing.
For example, in the case of paper P having a basis weight of 80 [gsm] of uncoated paper, it is "1" in Table 7, and the pressurizing member heating and cleaning operation is executed after fixing. In the case of coated paper, it is "0" regardless of the basis weight, and the pressurizing member heating and cleaning operation is not executed after fixing. When the control is changed depending on the brand of the paper P, "0" or "1" is set in advance for each brand and stored in the storage unit of the control unit 200.

The fixing device 40 includes a time when the pressurizing member heating and cleaning operation is executed after fixing, a time when it is determined that the post-fixing pressurizing member heating and cleaning operation is unnecessary after passing the paper, or an interrupting operation during the paper passing (fixing operation). Is executed, the integrated distance of the paper P is reset. The interrupt operation is executed when the power of the printer 100 is turned "OFF" during image drawing, when an abnormal operation is detected, a serviceman call, a jam, or a toner shortage occurs. By resetting the accumulated distance of the paper P, when the mileage of the next paper is used below the threshold value, the unnecessary post-fixing pressurizing member heating and cleaning operation may be mistakenly executed. It can be prevented and the occurrence of downtime can be prevented.

In the control shown in FIG. 5, when the integrated distance exceeds the threshold value during one paper passing (printing job), the pressurizing member heating and cleaning operation is executed after fixing. This is because it is unclear what kind of image was passed in the paper before the previous paper (for example, if the image is close to blank, the pressurizing member heating and cleaning operation is not required after fixing). It is based on the idea that it is not necessary to memorize the accumulated distance of the previous paper. Therefore, the integrated distance of the paper P is reset when it is determined that the pressurizing member heating and cleaning operation is unnecessary after the paper is passed, or when the interruption operation during the paper passing (fixing operation) is executed. ..

If it is determined that the pressurizing member heating and cleaning operation is unnecessary after fixing after passing the paper, the integrated distance is reset because the image information of the passing paper before the immediately preceding paper is unknown. When the interrupt operation is executed, the reload operation is performed once, and at that time, the cleaning operation by the cleaning web 11 is performed, so that it is not necessary to memorize the integrated distance, so the integrated distance is reset.

The fixing device 40 may be configured to prohibit interruption of other operations such as new paper passing and adjustment operation during execution of the pressurizing member heating and cleaning operation after fixing.
After the fixing operation is completed, the pressure roller 44 is pressed against the fixing belt 41 and rotated for a certain period of time. During the execution of the post-fixing pressure member heating and cleaning operation, the toner adhering to the surface of the pressure roller 44 is melted and removed. Give priority to doing. Therefore, the operation of shifting the fixing device 40 and the printer 100 to the standby state, the operation of starting a new paper passing, the operation of reloading, and the like are prohibited.

By prohibiting interruptions such as paper passing and adjustment operation until the post-fixing pressure member heating and cleaning operation is completed, the toner on the pressure roller 44 can be removed by the post-fixing pressure member heating and cleaning operation. It can be executed with priority over other operations. As a result, it is possible to prevent the toner from remaining attached to the surface of the pressure roller 44.

The fixing device 40 may be provided with an environmental temperature sensor 455 that detects the temperature of the installation environment of the device, and may be configured to change the control content of the pressurizing member heating / cleaning operation after fixing.

An example of the control table is shown in Table 8. In the configuration using the control table shown in Table 8, the environmental classification is divided from the indoor environmental temperature, and the contact maintenance time, which is the time for performing the pressurizing member heating and cleaning operation after fixing, is automatically set according to the environmental classification. Switch. For example, when the environmental temperature is 25 [° C.], the pressurizing member is heated and cleaned after fixing for 30 [seconds].
Since the amount of offset toner generated differs depending on the temperature of the paper P before the paper is passed, the cleaning performance during the heating and cleaning operation of the pressurizing member after fixing can be made constant regardless of the surrounding environment by switching depending on the surrounding environment.

The fixing device 40 calculates the integration distance by multiplying the transport distance of the paper P, which is a recording medium, by the integration ratio, which is a predetermined coefficient, and integrates the integration distance for each paper type paper thickness or each brand of the paper P. The integration ratio may be changed.

An example of the control table is shown in Table 9. In the configuration using the control table shown in Table 9, it is determined whether or not the integrated distance is equal to or greater than the threshold value for starting the pressurizing member heating and cleaning operation after fixing based on the following equation (1).
Σ (“length in the paper passing direction” × “integration ratio for each paper type paper thickness“ γ ”” ÷ 100) ≧ start threshold value
・ ・ ・ ・ (1)

The control unit 200 counts the length of the paper P that has passed through the fixing nip N in the paper-passing direction, and sets an integration ratio “γ” with respect to the length in the paper-passing direction for each paper type paper thickness of the paper P. , The integrated distance calculated by weighting (the left side of the above equation (1)) is compared with the start threshold (the right side of the above equation (1)).
When the calculated integrated distance is equal to or greater than the start threshold value, the pressurizing member heating and cleaning operation is executed after the fixing operation.

In this configuration, the integration ratio is set for each paper type paper thickness of the paper P, and the integration ratio is multiplied by the integration ratio of a larger value for the paper passing distance of the paper P that is easily offset, which is optimal for each paper P. After fixing at the timing, the pressurizing member heating and cleaning operation can be executed.
For example, if the paper type in Table 9 is "uncoated paper" and the paper thickness is "2" and the integration ratio is 200 [%], it is determined that the pressurizing member heating and cleaning operation is executed after fixing. The required number of sheets to be passed is 1/2 times that when the integration ratio is 100 [%]. Further, if the paper type in Table 9 is "uncoated paper" and the paper thickness is "5" and the integration ratio is 50 [%], it is judged that the pressure member heating and cleaning operation is executed after fixing. The required number of sheets to be passed is doubled when the integration ratio is 100 [%].

When the stored information on the paper P is a brand of the paper P, the integration ratio is set in advance from "0 [%]" to "1000 [%]" for each brand. When the integration ratio is "0 [%]", the pressure member heating and cleaning operation is not executed after fixing.

In the above-described embodiment, the case where the object to be cleaned is the pressure roller 44, which is heated so that the surface temperature becomes higher than that in the fixing operation after the fixing operation, is described. The object to be cleaned may be a fixing member such as a fixing belt 41 as a body to be cleaned by being heated so that the surface temperature becomes higher than that in the fixing operation.

In the above-described embodiment, the case where the image forming apparatus to which the present invention is applied is an electrophotographic printer is described, but the present invention is not limited to the printer, and other electrophotographic image forming apparatus such as a copier may be used. good. Further, it can be applied not only to an electrophotographic method but also to an image forming apparatus such as a copier or a printer using an inkjet method. As an image forming apparatus using an inkjet method, for example, there is an application to a fixing apparatus for drying an undried ink image supported on a recording medium (paper). In this case, after the fixing operation, the body to be cleaned to which the ink, which is an image forming substance, may adhere is heated to a higher temperature than that during the fixing operation, the adhered ink is softened, and the body to be cleaned is cleaned by the cleaning means. As a result, it is possible to prevent the image forming substance from remaining attached to the surface of the object to be cleaned.

The above description is an example, and the effect peculiar to each of the following aspects is exhibited.

(Aspect A)
A fixing member such as a fixing belt 41 that comes into contact with a surface on which an unfixed image such as a toner image of a recording medium such as paper P is formed to fix the unfixed image, and a fixing heater 45 or the like that heats the fixing member. A pressure member such as a pressure roller 44 that forms a fixing nip such as a fixing nip N that sandwiches a recording medium between the means and the fixing member, and a pressure roller cleaning device 410 that cleans the surface of the pressure member. In a fixing device such as the fixing device 40 provided with the pressure cleaning means, after the fixing operation for fixing the unfixed image, the surface temperature of the pressure member is heated so as to be higher than that in the fixing operation. It is characterized in that the pressurizing member is heated and cleaned after fixing by the pressurizing cleaning means.
According to this, as described in the above embodiment, the surface temperature of the pressure member is heated to be higher than that in the fixing operation, and the temperature is set to be equal to or higher than the melting temperature of the image forming substance such as toner. The image-forming substance adhered to the pressure member can be melted. Then, by cleaning the pressure member in the molten state of the image-forming substance by the pressure cleaning means, the image-forming substance can be easily removed, and the image-forming substance remains attached to the surface of the pressure member. It can be prevented from becoming a state.

(Aspect B)
In the aspect A, the heating conditions of the pressurizing member such as the pressurizing roller 44 in the post-fixing pressurizing member heating and cleaning operation are changed based on the information such as the paper type, the paper thickness and the brand of the recording medium such as the paper P. It is a feature.
According to this, as described in the above-described embodiment, when the fixing operation is performed on the recording medium in which the image-forming substance such as toner easily moves to the pressure member, the pressure member heating and cleaning operation is performed after the fixing. Run. As a result, it is possible to prevent the image forming substance from remaining attached to the surface of the pressure member. Further, when the fixing operation is performed on the recording medium in which the image forming substance is difficult to transfer to the pressure member, the pressure member heating and cleaning operation is not executed after the fixing. As a result, it is possible to shorten the downtime under the condition that the image forming substance does not easily adhere to the pressure member.

(Aspect C)
In aspects A or B, the heating conditions of the pressure member such as the contact maintenance time in the post-fixing pressure member heating and cleaning operation are changed based on the detection result of the installation environment condition such as the temperature of the installation environment of the device. And.
According to this, as described in the above-described embodiment, by switching the heating conditions based on the conditions of the installation environment, the cleaning performance during the heating and cleaning operation of the pressurizing member after fixing can be made constant regardless of the installation environment. ..

(Aspect D)
In the B or C aspect, the heating condition to be changed is a target temperature of a pressure member such as a pressure roller 44.
According to this, as described in the above-described embodiment, when the fixing operation is performed on a recording medium such as paper P in which an image-forming substance such as toner easily moves to the pressure member, the pressure member after fixing is performed. Set a high target temperature of the pressurizing member in the heating and cleaning operation. As a result, the image-forming substance adhered to the surface of the pressure member is melted, and the recoverability is improved. Further, when the fixing operation is performed on the recording medium in which the image forming substance is difficult to transfer to the pressure member, the target temperature of the pressure member in the pressure member heating and cleaning operation after fixing is set low. As a result, the time required for the pressure member to reach the target temperature is shortened, the time for executing the pressure member heating and cleaning operation after fixing is optimized, and the recording medium in which the image forming substance is difficult to transfer to the pressure member is easily transferred. The downtime under the conditions of can be shortened.

(Aspect E)
In any of aspects B to D, the heating condition to be changed is the heating time for the pressure member such as the pressure roller 44.
According to this, as described in the above embodiment, the time for executing the pressurizing member heating and cleaning operation after fixing is optimized, and the recording medium such as paper P in which the image forming substance is hard to be transferred to the pressurizing member is used. The downtime under the conditions can be shortened.

(Aspect F)
In any of aspects A to E, a contact / detachment mechanism such as a pressurizing mechanism 440 that attaches / detaches a pressurizing member such as a pressurizing roller 44 to / from a fixing member such as a fixing belt 41 is provided, and pressurization is performed after fixing. During the member heating and cleaning operation, the pressure member is maintained in contact with the fixing member, and the pressure member is heated by the fixing member heated by the fixing heating means such as the fixing heater 45. ..
According to this, as described in the above-described embodiment, the pressurizing member can be heated by the fixing heating means, and the means for heating the pressurizing member becomes unnecessary. Further, when a roller member having an elastic layer is used as the pressure member, by heating the surface of the pressure member by the fixing member, it is not necessary to heat the elastic layer of the pressure member to a temperature higher than the surface, and the elastic layer Can be suppressed from being deformed by thermal expansion. Furthermore, by controlling the contact / detachment mechanism to change the contact time of the pressure member with respect to the fixing member, it is possible to change the heating conditions such as the heating time of the pressure member during the heating and cleaning operation of the pressure member after fixing. It will be possible.

(Aspect G)
In the F aspect, the target temperature of the fixing member such as the fixing belt 41 in the post-fixing pressurizing member heating and cleaning operation is changed based on the information of the characteristics such as the brand of the recording medium of the paper P.
According to this, as described in the above embodiment, by changing the target temperature of the fixing member according to the information of the recording medium on which the fixing operation is performed, the pressure roller 44 or the like on the side receiving heat from the fixing member or the like. It is possible to shorten the time required for the pressurizing member to reach the target temperature. Therefore, it is possible to shorten the downtime by executing the pressurizing member heating and cleaning operation after fixing.

(Aspect H)
In any of aspects A to G, a cooling means such as a cooling mechanism 450 for cooling a pressure member such as a pressure roller 44 is provided.
According to this, as described in the above-described embodiment, it is possible to prevent the surface temperature of the pressure member from rising excessively, and the occurrence of hot offset and toner blister due to the surface temperature of the pressure member being too high. Can be prevented and the deterioration of image quality can be prevented.

(Aspect I)
In any of aspects A to H, the pressure cleaning means such as the pressure roller cleaning device 410 includes a band-shaped cleaning member such as a cleaning web 11 that comes into contact with the pressure member such as the pressure roller 44 and a band-shaped cleaning member. The strip-shaped cleaning member is provided with a web winding motor and a cleaning member moving mechanism such as the web winding shaft 11a.
According to this, as described in the above-described embodiment, it is possible to continue cleaning the pressure member using the portion of the strip-shaped cleaning member without deposits, and maintain the cleanability of the surface of the pressure member. It becomes possible to do.

(Aspect J)
In the aspect I, the movement amount of the strip-shaped cleaning member such as the cleaning web 11 by the cleaning member moving mechanism such as the web winding motor and the web winding shaft 11a is changed based on the information of the recording medium such as the brand of the paper P. It is characterized by.
According to this, as described in the above embodiment, when the fixing operation is performed on the recording medium such as the paper P in which the image forming substance such as toner easily moves to the pressure member, the strip-shaped cleaning member moves. Good cleanability can be maintained by setting a large amount. On the other hand, when the fixing operation is performed on a recording medium in which the image-forming substance is difficult to transfer to the pressure member, the amount of the band-shaped cleaning member used can be suppressed by setting the movement amount of the band-shaped cleaning member to be small, and the band-shaped cleaning member can be used. The life of the cleaning member can be extended.

(Aspect K)
In any of aspects A to J, the pressure cleaning means such as the pressure roller cleaning device 410 includes a cleaning member such as a cleaning web 11 that comes into contact with the pressure member such as the pressure roller 44, and the paper P or the like. The contact pressure of the cleaning member with respect to the pressure member during the heating and cleaning operation of the pressure member after fixing is changed based on the information of the recording medium.
According to this, as described in the above embodiment, when the fixing operation is performed on the recording medium such as the paper P in which the image forming substance such as toner easily moves to the pressure member, the contact pressure or the like is increased. Good cleanability can be obtained by increasing the contact pressure. On the other hand, when the fixing operation is performed on a recording medium in which the image forming substance is difficult to transfer to the pressure member, the contact pressure can be lowered to suppress a decrease in the life of the pressure member and the cleaning member.

(Aspect L)
In any of the aspects A to K, the threshold value of the number of transports (integrated distance, etc.) of the recording medium such as the paper P for determining whether or not the pressurizing member heating and cleaning operation can be executed after fixing, or the threshold value of the transport time is set. , It is characterized in that it is changed based on the information of the recording medium.
According to this, as described in the above-described embodiment, it is possible to optimize the timing of collecting the image-forming substance adhering to the pressure member such as the pressure roller 44 depending on the characteristics of the fixing recording medium. .. Further, depending on the characteristics of the recording medium, by not executing the pressurizing member heating / cleaning operation after fixing, it is possible to shorten the downtime due to the repeated execution of the pressurizing member heating / cleaning operation after fixing.

(Aspect M)
In any of the aspects A to L, a threshold value is set for the integrated distance of the transport distance of the recording medium such as paper P, and when the integrated distance becomes equal to or more than the threshold value, the pressurizing member heating and cleaning operation is executed after fixing. do.
According to this, as described in the above embodiment, when the integrated distance becomes equal to or more than the threshold value, the pressure member is attached to the pressure member such as the pressure roller 44 by executing the pressure member heating and cleaning operation after fixing. It is possible to optimize the timing of recovering the forming substance. Further, when the integrated distance is less than the threshold value, the downtime due to the repeated execution of the post-fixing pressurizing member heating / cleaning operation by not executing the post-fixing pressurizing member heating / cleaning operation can be shortened.

(Aspect N)
In the aspect M, the integration distance is calculated by multiplying the transport distance of a recording medium such as paper P by a predetermined coefficient such as an integration ratio, and the predetermined coefficient is changed based on the information of the recording medium. It is characterized by.
According to this, as described in the above-described embodiment, the pressurizing member heating and cleaning operation can be executed after fixing at the optimum timing for each recording medium.

(Aspect O)
In aspects M or N, when the post-fixing pressurizing member heating and cleaning operation is executed, when the post-fixing pressurizing member heating and cleaning operation is not executed after the fixing operation is completed, and when the fixing operation is interrupted. In addition, it is characterized by resetting the integrated distance.
According to this, as described in the above-described embodiment, it is possible to prevent an unnecessary heating and cleaning operation of the pressurizing member after fixing from being performed by mistake, and it is possible to prevent the occurrence of downtime.

(Aspect P)
In any of the aspects A to O, it is determined whether or not the pressurizing member heating and cleaning operation can be executed after fixing based on the information of the recording medium such as the paper P.
According to this, as described in the above embodiment, the post-fixing pressurizing member heating / cleaning operation can be executed at the optimum timing for each recording medium, and further, the unnecessary post-fixing pressurizing member heating / cleaning operation is erroneously executed. It is possible to prevent the occurrence of downtime.

(Aspect Q)
In any of the aspects A to P, when the pressurizing member heating and cleaning operation is executed after fixing, the transition to another operation is prohibited.
According to this, as described in the above embodiment, the removal of image-forming substances such as toner on the pressure member such as the pressure roller 44 by the pressure member heating and cleaning operation after fixing is prioritized over other operations. Can be executed. As a result, it is possible to prevent the image forming substance from remaining attached to the surface of the pressure member.

(Aspect R)
In any of aspects A to Q, the fixing member is a fixing belt such as a fixing belt 41 made of an endless belt, a heating roller such as a heating roller 43 having a fixing heating means such as a fixing heater, and a heat source inside. A fixing belt is provided between the fixing roller and the fixing roller 42, which forms a fixing nip such as a fixing nip N by sandwiching the fixing member with the pressure member in a structure in which an elastic layer is provided on the core metal. The tensioning member is a pressure roller such as a pressure roller 44 in which an elastic layer having a hardness of 200 [%] or less with respect to the elastic layer of the fixing roller is provided on the core metal.
According to this, as described in the above embodiment, in the configuration using the fixing belt, it becomes easy to maintain the temperature of the fixing belt at a predetermined value, and even if the image forming apparatus is speeded up, the fixing nip N or the like It is possible to supply a sufficient amount of heat to the nip portion of the belt. Further, by using a pressure roller in which an elastic layer having a hardness of 200 [%] or less is provided on the core metal with respect to the elastic layer of the fixing roller, a fixing nip having a wide nip width can be formed by parallel nips, and wrinkles are generated. And can cope with the speeding up of the image forming apparatus.

(Aspect S)
An unfixed image forming body is provided with a body to be cleaned such as a pressure roller 44 on which an image forming substance such as toner can adhere to the surface and a cleaning means such as a pressure roller cleaning device 410 for cleaning the surface of the body to be cleaned. In a fixing device such as a fixing device 40 that fixes a substance on a recording medium such as paper P, the surface temperature of the object to be cleaned is higher than that during the fixing operation after the fixing operation of fixing the unfixed image-forming substance. It is characterized in that the body to be cleaned is heated and cleaned after being fixed and cleaned by a cleaning means.
According to this, as described in the above-described embodiment, the surface temperature of the object to be cleaned is heated to be higher than that during the fixing operation, and the temperature is set to be equal to or higher than the melting temperature of the image-forming substance. The image-forming substance adhered to the surface can be melted. Then, by cleaning the object to be cleaned in which the image-forming substance is melted by a cleaning means, the image-forming substance can be easily removed, and the image-forming substance remains attached to the surface of the object to be cleaned. It can be prevented from becoming.

When the image forming apparatus provided with the fixing device according to the aspect S is an inkjet type image forming apparatus, the object to be cleaned to which the ink which is an image forming substance can adhere is a conveying roller or the like that imparts a conveying force to the recording medium. It is a member that can come into contact with the ink when the transport member or the ink is dried. Even in the fixing device provided in such an inkjet image forming apparatus, the surface temperature of the object to be cleaned is heated so as to be higher than that in the fixing operation to clean the surface of the object to be cleaned. It is possible to prevent the image forming substance from remaining attached.

(Aspect T)
In an image forming apparatus such as a printer 100 including an image forming means such as an image forming unit 110 that forms an image on a recording medium such as paper P and a fixing means for fixing the image on a recording medium, the aspect A is used as the fixing means. It is characterized by including a fixing device such as the fixing device 40 according to any one of the modes to S.
According to this, as described in the above embodiment, the image forming substance remains attached to the surface of the pressure member such as the black spot or the object to be cleaned, the contamination inside the device, the back stain of the paper P, and the like. It is possible to suppress the occurrence of troubles.

1 Optical writing unit 1YM First optical writing unit 1CK Second optical writing unit 2 Image forming unit 3 Photoreceptor 3Y Yellow photoconductor 3C Cyan photoconductor 3K Black photoconductor 3M Magenta photoconductor 4 Developer 5 Charging device 6 Drum cleaning device 11 Cleaning web 11a Web winding shaft 11b Web holding shaft 11c Web contact roller 30 Paper feed path 31 Pre-transfer transport path 32 Manual feed feed path 33 Manual feed tray 34 Resist roller vs. 35 Transport belt unit 36 Transport Belt 37 Transport drive roller 38 Transport driven roller 40 Fixing device 41 Fixing belt 42 Fixing roller 43 Heating roller 44 Pressurizing roller 44a Pressurizing roller shaft 45 Fixing heater 46 Tension roller 47 Inlet guide plate 48 Fixing separation plate 49 Transfer roller pair after fixing 50 Transfer switching device 51 Paper ejection path 52 Paper ejection path 52 Paper ejection roller vs. 53 Paper ejection tray 54 Retransmission path 55 Switchback path 56 Transfer path after switchback 59 Paper ejection sensor 60 Primary transfer unit 61 Intermediate transfer belt 62 Primary transfer roller 64 Toner adhesion amount Detection sensor 68 Secondary transfer bias roller 72 Ground driven roller 75 Intermediate transfer belt cleaning device 76 Secondary belt cleaning device 77 Secondary transfer belt 78 Secondary transfer unit 79 Secondary transfer drive roller 100 Printer 101 First paper cassette 101a First 1 Feeding Roller 102 2nd Feeding Cassette 102a 2nd Feeding Roller 103 Toner Bottle 110 Image Forming Unit 120 Paper Feeding Unit 200 Control Unit 300 Operation Panel 400 Housing 410 Pressurizing Roller Cleaning Device 415 Fixing Temperature Sensor 440 Pressurizing Mechanism 441 Pressurized moving motor 442 Pressurized moving lever 443 Pressurized moving shaft 445 Pressurized surface temperature sensor 450 Cooling mechanism 451 Blower 452 Duct 455 Environmental temperature sensor N Fixing nip T Unfixed toner

Japanese Unexamined Patent Publication No. 2017-15848

Claims (10)

A fixing member that comes into contact with the surface of the recording medium on which the unfixed image is formed to fix the unfixed image, and a fixing member.
Fixing heating means for heating the fixing member and
A pressure member forming a fixing nip that sandwiches the recording medium with the fixing member,
In a fixing device provided with a pressure cleaning means for cleaning the surface of the pressure member.
After the fixing operation for fixing the unfixed image, the pressure member is heated so that the surface temperature of the pressure member is higher than that during the fixing operation, and the pressure member is cleaned by the pressure cleaning means. It performs a heating and cleaning operation ,
The pressure cleaning means includes a band-shaped cleaning member that comes into contact with the pressure member, and a cleaning member moving mechanism that moves the band-shaped cleaning member so that a portion of the band-shaped cleaning member that comes into contact with the pressure member is different. ,
A fixing device characterized in that the amount of movement of the strip-shaped cleaning member by the cleaning member moving mechanism is changed based on the information of the recording medium. In the fixing device of claim 1,
A fixing device characterized in that the heating conditions of the pressure member in the post-fixing pressure member heating / cleaning operation are changed based on the information of the recording medium. In the fixing device of claim 1 or 2,
A fixing device characterized in that the heating conditions of the pressure member in the post-fixing pressure member heating / cleaning operation are changed based on the detection result of the installation environment condition. In the fixing device of claim 2 or 3,
A fixing device, wherein the heating condition to be changed is a target temperature of the pressurizing member. In the fixing device according to any one of claims 2 to 4.
A fixing device, wherein the heating condition to be changed is a heating time for the pressurizing member. In the fixing device according to any one of claims 1 to 5,
A contact / detachment mechanism for attaching / detaching the pressurizing member to / from the fixing member is provided.
During the post-fixing pressure member heating and cleaning operation, the pressure member is maintained in contact with the fixing member, and the pressure member is heated by the fixing member heated by the fixing heating means. A fixing device characterized by the fact that. In the fixing device according to any one of claims 1 to 6.
The pressure cleaning means includes a cleaning member that comes into contact with the pressure member.
A fixing device characterized in that the contact pressure of the cleaning member with respect to the pressure member during the heating and cleaning operation of the pressure member after fixing is changed based on the information of the recording medium. In the fixing device according to any one of claims 1 to 7.
A fixing device characterized in that the threshold value of the number of transports of the recording medium or the threshold value of the transport time for determining whether or not the pressurizing member heating and cleaning operation can be executed after fixing is changed based on the information of the recording medium. .. In the fixing device according to any one of claims 1 to 8.
A fixing device characterized in that a threshold value is set for the integrated distance of the transport distance of the recording medium, and when the integrated distance becomes equal to or more than the threshold value, the pressurizing member heating and cleaning operation is executed after the fixing. An image forming means for forming an image on a recording medium,
In an image forming apparatus including a fixing means for fixing the image on the recording medium,
An image forming apparatus comprising the fixing device according to any one of claims 1 to 9 as the fixing means.

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