JP5347322B2 - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing device, stably applying enough oil to first and second nip forming members; and to provide an image forming apparatus including an oil circulating mechanism. <P>SOLUTION: The image forming apparatus, in which a first nip forming member (a fixing belt 12) and a second nip forming member (a pressure roller 13) rotatably provided under the first nip forming member are disposed in contact with each other to form a fixing nip part N, includes: a first oil applicator 21 for applying oil to the first nip forming member; a second oil applicator 22 for applying oil to the second nip forming member; an oil receiver 254 collecting surplus oil in the first oil applicator 21; a tube 255 for supplying oil from the oil receiver 254 to the second oil applicator 22; an oil tank 251 for collecting oil from the second oil applicator 22; and an oil pump 252 and a carrying passage 253, which supply oil collected in the oil tank 251 to the first oil applicator 21. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an image forming apparatus including a fixing device, and more specifically, a copying machine including a fixing device that transfers a toner image formed using an electrophotographic method onto a sheet and then heats and fixes the toner on the sheet. The present invention relates to an image forming apparatus such as a printer, a facsimile machine, or a complex machine of these.

  In a fixing device in an electrophotographic image forming apparatus such as a copying machine or a printer, fixing performance is maintained while oil is used for a fixing member or the like to improve releasability from toner. In particular, in a full-color electrophotographic apparatus, a lot of oil is used in the fixing device.

  In recent years, the use of an endless fixing belt as a fixing member of a fixing device is often employed because of shortening of the warm-up time. For example, as shown in FIG. 1, a fixing belt 92 that is stretched over a fixing roller 84 and a heating roller 83 with a certain tension, and a pressure rotatively contacting the fixing belt 92 to form a fixing nip portion A. There is a fixing device configured to include a pressure roller 85 (see, for example, Patent Document 1).

  Here, an oil application roller R1 is provided as an oil application device for applying oil to the fixing belt 92, and the oil supplied from an oil supply unit (not shown) is rotated by the rotating oil application roller R1. The abutment point 95 is applied. Then, the oil-coated portion of the fixing belt 92 moves to the fixing nip portion A by the rotation of the fixing belt 92, and contributes to releasability from the recording medium (transfer paper) onto which the toner image is transferred. Next, in the fixing nip portion A, a part of the oil of the fixing belt 92 has moved to the surface of the pressure roller 85, and the releasability of the pressure roller 85 is also improved. The excess oil in the pressure roller 85 flows into the oil pan 96 below the pressure roller 85 and is collected.

JP 2003-302857 A

  However, in the conventional fixing device, the amount of oil applied from the oil applying device may be reduced, and the releasability of the recording medium that has been subjected to the fixing process in the fixing member (first nip forming member) may deteriorate. Further, the amount of oil adhering to the pressure member (second nip forming member) side may be reduced, and the releasability of the recording medium that has been subjected to the fixing process on the pressure member may be deteriorated.

  The present invention has been made in view of the above problems in the prior art, and includes a fixing device and an oil circulation mechanism in which a sufficient amount of oil is stably applied to the first and second nip forming members. An object is to provide an image forming apparatus.

The present invention provided to solve the above problems is as follows.
[1] A first nip forming member provided rotatably and a second nip forming member provided rotatably below the first nip forming member are in contact with each other to form a fixing nip portion. A first oil application device that applies oil to the first nip forming member; a second oil application device that applies oil to the second nip forming member; and an oil that collects excess oil in the first oil application device A receiver, a supply path for supplying oil from the oil receiver to the second oil application device, an oil recovery unit for recovering oil from the second oil application device, and the oil recovered by the oil recovery unit in the first 1 with an oil supply device that supplies oil to the oil application device ,
The amount of oil supplied to the first oil application device is A, the amount of oil recovered by the oil recovery unit is J, the amount of oil applied to the surface of the transfer paper on the first nip forming member side is E, and the first amount of transfer paper is the first. When the amount of oil applied to the surface on the 2-nip forming member side is H1, and the amount of excess oil collected by the oil receiver is K, the following equations (1) to (4)
A = J + (E + H1) (1)
A> J (2)
A> E + H1 (3)
K> J (4)
An image forming apparatus satisfying the requirements .
[2] The first oil application device includes an oil application unit that applies oil to the first nip forming member , and an oil supply unit that supplies oil to the oil application unit,
The oil supply unit is disposed adjacent to an oil input port for supplying oil, an oil storage unit for storing oil supplied from the oil input port, and a lower side of the oil storage unit. A supply felt in which oil is supplied to the part and oil overflowing from the upper part of the oil reservoir part is supplied, and in the width direction of the oil reservoir part, from the inside of the recess of the oil reservoir part to an area other than the oil inlet The image forming apparatus according to [1], wherein the image forming apparatus includes at least a hollow felt connected to a supply felt .
[3] The second oil application device includes an immersion tank that holds oil and is provided below the second nip forming member, and a part of the second nip forming member is immersed therein. An oil regulating member that regulates the amount of oil adhering to the second nip forming member provided downstream of the two nip forming member and in front of the fixing nip portion; and a downstream of the second nip forming member from the immersion tank. The image forming apparatus according to [1], further including a cleaning member that contacts the upstream side of the rotation of the second nip forming member relative to the oil regulating member and cleans the surface of the second nip forming member .
[4] The second oil application device includes an immersion tank that holds oil and is provided below the second nip forming member and in which a part of the second nip forming member is immersed, and the entire immersion tank is accommodated. And [1] having an oil receiver provided with an oil discharge port to the oil recovery section, and an oil filter disposed between the immersion tank and the oil receiver for filtering oil overflowing from the immersion tank. The image forming apparatus described.

  According to the present invention, since a sufficient amount of oil is stably supplied to the first and second oil application devices by the oil circulation mechanism, a sufficient amount of oil is supplied to both the first and second nip forming members. It becomes possible to apply stably. Therefore, it is possible to maintain good releasability of the recording medium.

The image forming apparatus according to the present invention will be described below.
First, the configuration of an embodiment of a fixing device used in the present invention will be described.
As shown in FIG. 2, the fixing device 100 used in the present invention is a fixing member (fixing member) that is a first nip forming member that is stretched around the fixing roller 11 and the heating roller 14 with a constant tension inside a fixing cover 100c. A belt 12), a pressure member (pressure roller 13) which is a second nip forming member that presses the fixing member (fixing belt 12) rotatably and forms a fixing nip N. Fluorine coating is applied to the surface of the fixing nip portion N on the sheet discharge side, the front end of which is disposed close to the fixing member (fixing belt 12) and prevents the sheet P from being wrapped around the fixing member (fixing belt 12). The separation claw 16a and the sheet discharge side of the fixing nip portion N are arranged in contact with the pressure member (pressure roller 13) and the sheet P is applied to the pressure member (pressure roller 13). roll It comprises a separation pawl 16b fluorine coating has been applied to the surface to prevent attached, a cleaning mechanism 17 for cleaning the fixing belt 12 is pressed against the cleaning web, the.

  Here, the fixing belt 12 is an endless belt and has a two-layer structure in which an elastic layer such as a silicon rubber layer is formed on a base material such as nickel, stainless steel, or polyimide. The fixing roller 11 has a metal core and silicon rubber. In order to shorten the warm-up time, foamed silicon rubber may be used so that the heat of the fixing belt 12 is not easily absorbed. The heating roller 14 is an aluminum or iron hollow roller and has a heat source including a heater 14h such as a halogen heater. The heat source may be an induction heating mechanism (IH). A plurality of hollow pipes are formed in the thick portion of the hollow roller of the heating roller 14 so that the longitudinal direction thereof is the width direction of the heating roller 14, and a heat pipe 14a embedded uniformly in the circumferential direction of the heating roller 14 is provided. Have. The heat pipe 14a improves the heat transfer from the heater 14h to the roller surface, and the fixing belt 12 is heated quickly and uniformly.

  When the fixing device 100 is driven, for example, the fixing belt 12 is rotated in the clockwise direction in the drawing, and the fixing belt 12 discharges the sheet P in a state where an appropriate tension is applied by pressing the tension roller 15 ( In FIG. 2, the pressure roller 13 rotates in the clockwise direction. The roller to be driven is not limited to the fixing roller 11 but may be a pressure roller 13 or a heating roller 14. Further, at the time of fixing, the fixing belt 12 is heated to a predetermined temperature (for example, a temperature suitable for toner fixing) detected by a thermistor (not shown) due to heat generated by a heater 14 h disposed inside the heating roller 14. Is done. In the present invention, the fixing belt 12 (endless belt) shown in FIG. 2 is shown as the fixing member. However, the fixing member is not limited to this and may be a hollow cylindrical roller (fixing roller).

  The pressure roller 13 is a cylindrical roller in which an elastic layer such as silicon rubber is usually provided on a core metal such as aluminum or iron. Further, the pressure roller 13 can be moved to the fixing belt 12 side by a pressure / pressure releasing means (not shown) and pressed, and the pressure roller 13 can be moved away from the fixing belt 12 to release the pressure. When 100 is driven, the pressing / depressurizing means presses the pressing roller 13 against the fixing belt 12 by pressing it toward the fixing belt 12 with a constant pressure. Further, when necessary, such as during fixing, the pressure roller 13 is heated to a predetermined temperature by the heat generated by the heater 13h disposed therein. In the present invention, the form of the pressure roller 13 (roller type) shown in FIG. 2 is shown as the pressure member. However, the present invention is not limited to this, and an endless belt shape spanned between two rollers is used. It is good also as a pressurizing member (belt type).

  In the fixing device 100, the surface of the fixing belt 12 is heated to a predetermined temperature in a state where the fixing belt 12 and the pressure roller 13 are rotationally driven, and the sheet on which the unfixed toner T is formed in the fixing nip portion N. P is passed (paper passing from the right side to the left side in the figure), and fixing is performed by thermally fusing unfixed toner onto the sheet P by pressurization and heating at the fixing nip N.

Next, the toner-fixed sheet P is discharged from the fixing nip portion N. At this time, the sheet P may come out while being wound around the fixing belt 12 or the pressure roller 13. As countermeasures, an oil application device 21 that is a first oil application device that improves the releasability by applying oil to the fixing belt 12 and a second method that improves the releasability by applying oil to the pressure roller 13. An oil application device 22 which is an oil application device is provided. The oil used here is preferably a heat-resistant and non-volatile oil, such as silicone oil. Further, when the leading ends of the separation claws 16 a and 16 b come into contact with the leading end of the sheet P, the sheet P is separated from the fixing belt 12 or the pressure roller 13. The sheet P discharged from the fixing nip portion N passes through a predetermined discharge path and is sent out from the fixing device 100.
Up to this point, the basic configuration of the fixing device 100 is the same as the configuration of the conventional fixing device.

Here, FIG. 3 shows an example of an oil application device that applies oil to the fixing belt 12 as a conventional oil application device.
The oil application device 71 has an oil input port 71a for supplying oil to the oil receiver 71b from the outside of the fixing device, a U-shaped sheet metal processing, and a bowl-shaped oil receiver 71b having an oil transmission hole 71c on the bottom side. , A supply felt 71d for receiving oil from the oil transmission hole 71c, which is provided in contact with the side surface of the oil receiver 71b disposed so that the side surface including the oil transmission hole 71c of the oil receiver 71b is inclined downward. A supply roller 21e that receives oil from the oil supply unit, an oil supply unit that includes a metering blade 21f that adjusts the oil adhesion amount (holding amount) of the supply roller 21e, and an application roller 23 that applies oil from the oil supply unit to the fixing belt 12. An oil application unit.

  In the oil supply section, the oil supplied from the oil input port 71a is stored in the oil receiver 71b, and when the oil level is above the oil transmission hole 71c, the oil O passes through the oil transmission hole 71c. It is supplied from the receptacle 71b to the supply felt 71d. Next, in the supply felt 71d, the oil O is sent to the upper supply roller 21e from the position (lower side) of the oil transmission hole 71c by capillary action, and the oil adheres to the supply roller 21e at the portion in contact with the supply roller 21e. To do. The supply roller 21e is rotationally driven (clockwise in the figure) by a driving force input from the outside, and a portion to which oil is attached is rotated toward the application roller 23 by the supply felt 71d. Oil was supplied to the application roller 23 after the amount of adhesion was adjusted by the blade 21f. After the oil is supplied to the application roller 23 at a position in contact with the supply roller 21e, the oil adhesion portion of the application roller 23 contacts the fixing belt 12 and the oil is applied to the fixing belt 12.

With the above mechanism, oil is applied from the oil application device 71 to the fixing belt 12, and the oil contains fine solid impurities (for example, dust or calcium carbonate derived from the recording medium). Therefore, there is a problem that the impurities are deposited on the supply felt 71d with time. That is, when impurities accumulate on the supply felt 71d, the movement of oil due to capillary action is inhibited, the amount of oil supplied to the supply roller 21e decreases, and the amount of oil applied to the fixing belt 12 decreases. As a result, the releasability of the recording medium in the fixing belt 12 is deteriorated. In addition, when the conveyance speed of the recording medium becomes a high linear speed (for example, 300 mm / s or more) or when coated paper is used for the recording medium, a sufficient amount of oil is stably applied to the fixing belt 12 in particular. However, the oil supply due to the capillary action of the oil in the supply felt 71d is not enough to supply the oil, and the releasability is also a problem.
In order to solve these problems, the inventors have intensively studied paying attention to the fact that the capillary phenomenon of the supply felt 71d is a bottleneck, and have invented the first oil application device. Hereinafter, the 1st oil application device used for the present invention is explained.

  FIG. 4 shows a schematic diagram of the main part of the first oil application device in the fixing device used in the present invention. That is, the fixing device 100 used in the present invention includes a fixing member (fixing belt 12) that is rotatably provided, and a pressure member (pressure application) that contacts the fixing member and forms a fixing nip portion (fixing nip portion N). Roller 13), an oil application part (application roller 23) for applying oil to a predetermined width of the fixing member or pressure member, and an oil supply part (oil input port 21a, oil reservoir part) for supplying oil to the oil application part 21b, a support plate 21c, a supply felt 21d, a supply roller 21e, and a metering blade 21f), a first oil application device (oil supply device 21), and the oil supply unit is an oil supply device (described later). Is a bowl-shaped depression for storing oil supplied from an oil inlet and having a longitudinal direction parallel to the width direction of the oil application part. The oil reservoir portion (oil reservoir portion 21b) is provided above the adjacent oil supply member (supply felt 21d), and the oil overflows from the upper portion of the oil reservoir portion when oil is poured into the oil reservoir portion. And is configured to be supplied to the adjacent oil supply member.

FIG. 5 is a perspective view showing the configuration of the oil reservoir 21b, the support plate 21c, and the supply felt 21d, which are the main parts of the oil supply unit.
The oil reservoir 21b is a bowl-shaped depression formed of a flange 21b2 having a V-shaped cross section and a side plate 21b3 provided in a manner to block the groove of the flange at both longitudinal ends of the flange 21b2. At this time, the support plate 21c is above the supply roller 21e and the longitudinal direction of the flange portion 21b2 is parallel to the width direction of the supply roller 21e (that is, the width direction of the application roller 23 and the width direction of the fixing belt 12). It is supported by. In FIG. 5, the oil reservoir portion 21b is formed with a flange portion 21b2 by a folded end portion of the support plate 21c and a band plate with the end portion fixed to the folded portion, and side plates at both longitudinal ends of the flange portion 21b2. Although the configuration in which 21b3 is fixed is shown, the present invention is not limited to this, and the flange portion 21b2 may be formed by sheet metal and the side plate 21b3 is attached, or the flange portion 21b2 and the side plate 21b3 may be integrally formed. . The oil reservoir 21b may be made of a heat-resistant metal material or plastic that does not react with the oil used.

  In addition, the end facing the adjacent oil supply member (supply felt 21d) is the other end (the other end of the flange 21b2 and the end of the side plate 21b3) of the open end of the oil reservoir 21b. It becomes a mouth cut part (mouth cut part 21b1) whose height position is lower than that. When the fixing device 100 is driven, oil is introduced into the center of the oil reservoir 21b in the width direction until the oil overflows from the oil reservoir 21b (injected from the arrow position in the figure). Oil preferentially overflows from 21b1 and is supplied to the oil application part (application roller 23) via the adjacent oil supply member (supply felt 21d) and supply roller 21e. At this time, since oil overflows from the entire width of the mouth cut portion 21b, the oil is supplied to a predetermined width (for example, full width) of the supply roller 21e and the application roller 23 via the supply felt 21d, and then the predetermined width of the fixing belt 12 is reached. The oil is applied to (for example, full width).

  The support plate 21c has a U-shaped cross section and supports the oil reservoir 21b and the supply felt 21d. At this time, the supply felt 21d can be brought into contact with the supply roller 21e with a constant pressing force if an appropriate spring characteristic is given, such as a metal material processed by sheet metal.

  The supply felt 21d is disposed adjacent to the oil reservoir 21b, and supplies oil from the upper portion of the oil reservoir 21b to the oil application part (application roll 23) side. Specifically, the supply felt 21d is between the oil reservoir 21b and the supply roller 21e and protrudes at the same height as or above the end of the mouth cut portion 21b1 of the oil reservoir 21b. It arrange | positions in contact with the oil reservoir part 21b. Further, the supply felt 21d is a compressed sheet made of, for example, a fiber that does not react with heat-resistant oil (for example, a meta-aramid fiber), and allows the oil to pass between the fibers while holding the oil inside. Is. Therefore, the fiber basis weight (mesh) of the supply felt 21d may be coarser than that for the purpose of filtering impurities. Thereby, the supply felt 21d can receive the oil overflowing from the mouth cut portion 21b1, and can flow the oil along the supply felt 21d. Here, oil flows from the upper part of the oil reservoir 21b to the supply roller 21e by the action of gravity (free fall), and the supply felt 21d supplies oil to the supply roller 21e at the contact portion with the supply roller 21e.

  In addition, the oil supply unit includes a supply roller 21e that receives oil from the supply felt 21d, and a metering blade 21f that adjusts the oil adhesion amount (holding amount) of the supply roller 21e. Among these, the supply roller 21e is made of a material corresponding to the oil used on the surface, and is made of, for example, silicon rubber. The metering blade 21f is a blade made of a material that does not damage the surface of the supply roller 21e while restricting the amount of oil adhering to the supply roller 21e, and is preferably formed of, for example, fluororubber.

With the above configuration, oil is supplied from the oil supply unit to the oil application unit as follows.
(S11) When the driving of the fixing device 100 is started, the rotation of the supply roller 21e starts with the rotation of the fixing belt 12, and the rotation of the application roller 23 in contact with the fixing belt 12 and the supply roller 21e is also started.
(S12) At the same time, oil starts to be supplied from the oil input port 21a to the oil reservoir 21b, and the oil is stored in the oil reservoir 21b.
(S13) The oil is continuously supplied, and the oil overflows from the oil reservoir 21b. At this time, the oil overflows from the full width of the mouth cut portion 21b1 and is supplied to the supply felt 21d (full width).
(S14) In the supply felt 21d, the oil passes through the inside from the upper side (upper side) of the oil reservoir 21b to the lower side, and the oil is supplied to a predetermined width of the supply roller 21e at the contact portion of the supply roller 21e.
(S15) The portion of the supply roller 21e to which the oil is supplied moves by the rotation of the supply roller 21e, and then the amount of oil adhering to the supply roller 21e is regulated by the contact of the metering blade 21f.
(S16) The oil of the supply roller 21e is supplied to a predetermined width of the application roller 23 at the contact portion with the application roller 23. Finally, the oil adhering to the application roller 23 is applied to a predetermined width of the fixing belt 12.

  As described above, in the oil application device 21, the supply using the felt capillary phenomenon is not included in the process of supplying oil from the oil supply unit to the oil application unit, and in particular, the supply roller 21e from the oil reservoir 21b. Since the oil is flowed down from above to below using the action of gravity, a sufficient amount of oil can be stably supplied.

  By the way, the oil used in the fixing device 100 has a certain degree of viscosity, and even if the oil is supplied from the oil inlet 21a to the oil reservoir 21b in the oil supply portion, the oil immediately expands in the width direction of the oil reservoir 21b. Do not mean. That is, in the width direction of the oil reservoir 21b, the oil is most accumulated at the position of the oil inlet 21a and rises, and the oil height tends to decrease toward the end. For this reason, the distribution of the amount in the width direction of the oil flowing into the supply roller 21e beyond the mouth cut portion 21c tends to be non-uniform.

  Therefore, as a countermeasure, for example, a drainage felt connected to the supply felt 21d from the inside of the recess of the oil reservoir 21b is provided in a region in the width direction other than the oil inlet 21a in the oil reservoir 21b, and a width other than the oil inlet 21a is provided. It is good to make it easy to supply oil from the direction area. In this case, oil is supplied from the bare felt to the supply felt 21d by the capillary action of the oil, but it is used as an auxiliary to adjust the distribution in the width direction of the oil supply, from the stick felt to the supply felt 21d. Since the distance is short, there is no practical problem.

  Alternatively, a plurality of oil inlets 21a to the oil reservoir 21b may be provided in the width direction of the oil reservoir 21b so that the oil height in the width direction of the oil reservoir 21b is made uniform.

  Moreover, about the mouth-cut part 21b1, the edge part height of the position corresponding to the oil inlet 21a to the oil reservoir part 21b is made higher than the edge part height of the other position, thereby overflowing from the mouth-cut part 21b. You may adjust the quantity of the width direction of the oil to come out.

Up to this point, the oil application apparatus having the configuration shown in FIG. 4 has been described. However, the present invention is not limited to this configuration, and the same operational effects can be obtained in the configuration examples (1) and (2) shown below. can get.
In FIG. 6, the other structural example (1) of the 1st oil application | coating apparatus which is 1 aspect of this invention is shown.
Here, in the configuration shown in FIG. 4, the supply felt 21 d is omitted, the oil reservoir 21 b and the supply roller 21 e are adjacent to each other, and the other configuration is the same. That is, the fixing device 100 used in the present invention includes a fixing member (fixing belt 12) that is rotatably provided, and a pressure member (pressure application) that contacts the fixing member and forms a fixing nip portion (fixing nip portion N). Roller 13), an oil application part (application roller 23) for applying oil to a predetermined width of the fixing member or pressure member, and an oil supply part (oil input port 21a, oil reservoir part) for supplying oil to the oil application part 21b, a support plate 21c, a supply roller 21e, a metering blade 21f), and a first oil application device (oil supply device 21A). The oil supply unit stores oil supplied from an oil supply port. An oil reservoir portion (oil reservoir portion 21b), which is a bowl-shaped recess that is disposed in parallel with the width direction of the oil application portion, is adjacent to the oil reservoir portion. The oil supply member (supply roller 21e) is disposed above and is configured so that when oil is poured into the oil reservoir, the oil overflows from the upper portion of the oil reservoir and is supplied to the adjacent oil supply member. It is a thing.

Moreover, the other structural example (2) of the 1st oil application apparatus which is 1 aspect of this invention is shown in FIG.
Here, in the configuration shown in FIG. 4, the supply felt 21 d, the supply roller 21 e, and the metering blade 21 f are omitted, and an oil reservoir 21 b and an application felt 23 ′ are used instead of the application roller 23 as an application felt 23 ′. Adjacent configuration. That is, the fixing device 100 used in the present invention includes a fixing member (fixing belt 12) that is rotatably provided, and a pressure member (pressure application) that contacts the fixing member and forms a fixing nip portion (fixing nip portion N). Roller 13), an oil application part (application felt 23 ') for applying oil to a predetermined width of the fixing member or pressure member, and an oil supply part (oil input port 21a, oil reservoir) for supplying oil to the oil application part A first oil application device (oil supply device 21B) having a portion 21b), and the oil supply portion is a bowl-shaped depression for storing oil supplied from an oil input port, and has a longitudinal direction. An oil reservoir (oil reservoir 21b) disposed parallel to the width direction of the oil application portion is provided above the adjacent oil application portion (application felt 23 '), and the oil reservoir When oil is supplied to the oil reservoir, the oil overflows from the upper part of the oil reservoir and is supplied to the adjacent oil application part. The coating felt 23 ′ at this time may be the same as the supply felt 23.

  Incidentally, in the conventional fixing device shown in FIG. 1, the oil applied to the upper fixing belt 92 is transferred to the lower pressure roller 85 at the fixing nip portion, and the release property of the pressure roller 85 is ensured. Was. However, when an image is formed on a sheet by continuous paper passing, the oil is transferred to the pressure roller 85 only between the sheets (between the sheets). There was a problem that the releasability deteriorated.

  In addition, when the image forming process is performed at a high linear velocity of 300 mm / s or more, for example, 400 mm / s, the fixing device adopts a horizontal path method in which the sheet is conveyed in the horizontal direction. Due to the influence of gravity and further the influence of the nip state between the fixing belt 92 and the pressure roller 85, the sheet tends to be easily wound around the pressure roller 85 on the exit side of the fixing nip portion. The sheet releasability at 85 has been required.

  Therefore, as shown in FIG. 8, a fixing device provided with an oil application functional component R3 that contacts the pressure roller 85 and applies oil has been studied. However, in this method, there is no supply of oil from the outside. Even if there was a small amount, only a small amount of oil could be applied, and the release property in the pressure roller 85 was not sufficient. In particular, in the case of image formation at a high linear velocity or when using a sheet that easily absorbs oil such as coated paper whose surface is coated with a drug in order to obtain high image quality, the pressure roller 13 side is also sufficient. Although an amount of oil is required, it was difficult to cope with the method of FIG.

  In addition, the uniformity of the oil adhesion amount distribution in the width direction of the pressure roller 85 was not good, and the influence on the image quality (gloss) due to uneven application of oil was also a problem. At this time, it is conceivable to make the oil adhesion amount distribution uniform by bringing a blade or the like into contact, but since the original oil adhesion amount is small, the friction between the blade and the pressure roller 85 becomes very large, There was a problem of pulsation in which the pressure roller 85 did not rotate smoothly but rotated a little and stopped (referred to as stick-slip).

Furthermore, there are restrictions on the pressure roller 85 side for the oil supply and application method. That is, it is possible to easily supply a large amount of oil to the fixing belt 92 by pouring off the oil from above the fixing belt 92 with respect to the fixing belt 92 disposed above the sheet path. However, the pressure roller 85 is disposed on the lower side of the sheet path, and it is difficult to secure a space for disposing the oil application device above the pressure roller 85.
Accordingly, the inventors have paid attention to the fact that it is relatively easy to secure a space below the pressure roller, and have intensively studied to come up with the second oil application device.

FIG. 9 shows a schematic diagram of a main part related to the second oil application device in the fixing device 100 used in the present invention.
That is, the fixing device 100 according to the present invention includes a first nip forming member (fixing member (fixing belt 12)) that is rotatably provided and a second nip that is rotatably provided below the first nip forming member. A nip forming member (pressure member (pressure roller 13)) is in contact with the nip forming member (pressing roller 13) so as to form a fixing nip portion (fixing nip portion N), and holds the second oil (oil O) while holding the oil (oil O). An oil tank (oil tank 22a (sub oil pan 22a1)) provided below the nip forming member and in which a part of the second nip forming member is immersed, and the second nip forming member rotating downstream of the oil tank. And a second oil application device (oil application device 22) that is provided in front of the fixing nip portion and has an oil restriction member (blade 22b) that restricts the amount of oil adhering to the second nip forming member.

  Here, the oil tank 22a holds the oil O and a sub oil pan 22a1 that is an immersion tank in which a part of the pressure roller 13 is immersed, and a main oil pan that is an oil receiver in which the entire sub oil pan 22a1 is stored. 22 a 2, which has a two-tank structure and is fixedly arranged in the cover 100 c of the fixing device 100. At this time, the oil O applied to the pressure roller 13 is supplied to the sub oil pan 22a1 from the outside of the oil applying device 22 (oil receiver that collects excess oil of the oil applying device 21), and the oil O is supplied to the sub oil pan 22a1. It has a structure that can be stored in. The sub oil pan 22a1 is a rectangular oil pan, and its length in the longitudinal direction is at least equal to the width of the roller portion of the pressure roller 13.

  Further, the pressure roller 13 has the entire width of the roller, and a part of the roller radial direction is always immersed in the sub oil pan 22a1 without any trouble as a device. That is, the oil level of the sub oil pan 2a1 is sufficiently higher than the lower end of the pressure roller 13 in the pressurized state, and the lower end of the pressure roller 13 is in a state where the pressure roller 13 is released. The bottom surface of the sub oil pan 22a1 is not in contact. Note that the oil O only needs to be applied before the sheet P passes through the fixing nip N. Therefore, the pressure roller 13 does not always need to be immersed in the sub oil pan 22a1, for example, the pressure roller 13 rotates. When the operation is started, the pressure roller 13 may be immersed in the sub oil pan 22a1.

  The main oil pan 22a2 is an oil receiver that receives the oil O overflowing from the sub oil pan 22a1. Further, an oil discharge port to an oil tank (described later) for collecting the oil O is provided at the lower part of the main oil pan 22a2.

  Note that it is preferable to use a metal material, plastic, or the like that does not react to the oil used and is heat resistant for both the sub oil pan 22a1 and the main oil pan 22a2.

  The blade 22b is a spatula-like elastic member having a width at least equal to or greater than the width of the pressure roller 13, and its longitudinal direction is always in contact with the surface of the pressure roller 13 in the width direction. The oil adhering amount at 13 is regulated to be a predetermined amount while being uniform in the width direction. The blade 22b is made of a material that does not damage the surface of the supply roller 21e, and is formed of, for example, fluororubber.

  Here, the pressure roller 13 is made of a material corresponding to the oil O used on the surface, and is formed of silicon rubber when the coil O is silicone oil, for example. Therefore, when the pressure roller 13 is immersed in the oil O in the oil tank 22a, the silicon rubber swells and holds the oil O, but the blade 22b pressurizes the surface of the pressure roller 13 in this state. The abutment is made at the lower position of the roller 13 so that the oil O is scraped off from the pressure roller 13. Specifically, the blade 22b is disposed so that the angle θ formed between the tip of the blade 22b and the tangent line of the pressure roller 13 is an acute angle of less than 90 degrees, and the tip is opposed to the rotation direction of the pressure roller 13. It functions to scrape off excess oil O on the surface of the pressure roller 13 toward the oil tank 22a. As a result, the surface of the pressure roller 13 is in a state where a sufficient amount of oil is uniform in the width direction to ensure releasability. In addition, surplus oil in the pressure roller 13 is collected in the oil tank 22a, and a circulation system that is used for oil application to the pressure roller 13 again is configured.

  Further, the oil application device 22 preferably has a cleaning felt 22c, which is a cleaning member that contacts the pressure roller 13 and cleans the surface of the pressure roller 13 between the oil tank 22a and the blade 22b. The cleaning felt 22c is a compressed sheet made of, for example, a fiber that does not react with heat-resistant oil (for example, a meta-aramid fiber), and permeates the oil while capturing fine solid impurities inside. It is. Thereby, it is possible to remove fine solid impurities (for example, dust or calcium carbonate derived from the sheet P) in the oil O while leaving the oil O on the surface of the pressure roller 13.

  The cleaning felt 22c is supported by an appropriate support member so as to come into contact with the pressure roller 13. However, the support member should be provided with appropriate spring characteristics, such as a metal material processed by sheet metal. For example, the cleaning felt 22c can be brought into contact with the pressure roller 13 with a constant pressing force to adjust the oil adhesion amount.

With the above configuration, oil application from the oil application unit 22 to the pressure roller 13 is performed as follows.
(S21) First, when the driving of the fixing device 100 is started, the rotation of the fixing belt 12 is started, and then the pressure roller 13 is brought into contact with the fixing belt 12 with a certain pressure by the pressure depressurizing means. N is formed. At the same time, the pressure roller 13 starts to rotate around the fixing belt 12 by rotating. The pressure roller 13 may be driven and rotated (S22) When the pressure roller 13 starts rotating, the roller surface of the pressure roller 13 immersed in the oil tank 22a (sub oil pan 22a1). However, it is pulled up in the direction of the fixing nip N with the oil O attached.
(S23) Next, the oil O adhering to the surface of the pressure roller 13 passes through the cleaning felt 22c, and solid impurities are removed.
(S24) Next, the adhesion of the oil O on the surface of the pressure roller 13 is regulated by the blade 22b so as to be uniform in the width direction, and in this state, the oil moves to the fixing nip portion N.

  As described above, in the present invention, the oil application is performed by the dipping method using the space below the pressure roller 13 with respect to the pressure roller 13 below the fixing nip portion N. It is possible to supply a stable amount of oil.

FIG. 10 shows a view of the oil application device 22 as viewed from above. The blade 22b is omitted.
FIG. 10 shows a state in which the oil level of the oil tank 22a is covered with an oil scattering prevention member 22d. Specifically, the oil splash prevention member 22d covers the area on the liquid level of the sub oil pan 22a1 and the main oil pan 22a2 of the oil tank 22a, excluding the portion where the pressure roller 13 is immersed. Further, covering the oil liquid surface under the cleaning felt 22c may be omitted. Thereby, it is possible to prevent the oil O from being scattered from the oil level of the oil tank 22a due to the rotation of the pressure roller 13 or other vibrations, and adhering to the peripheral device or the sheet P to be contaminated.

  The oil scattering prevention member 22d is preferably a compressed sheet (felt) made of, for example, fibers that do not react with heat-resistant oil (for example, meta-aramid fibers). This may be floated on the liquid surface or may be arranged away from the liquid surface. Alternatively, the oil scattering prevention member 22d may be a plurality of spherical members floated so as to cover the oil liquid level.

  Here, a configuration example is shown in which a fixing member (fixing belt 12) is disposed as the first nip forming member on the upper side of the fixing device, and a pressure member (pressure roller 13) is disposed as the second nip forming member on the lower side. However, the present invention is not limited to this, and a roller type fixing member may be disposed as the first nip forming member on the upper side, and a belt type pressing member may be disposed below the second nip forming member. FIG. 11 shows an example of the configuration. Here, the fixing roller 12a, which is a first nip forming member that is rotatably arranged on the upper side, and the second nip forming member that is rotatably supported by rollers R11, R14, and R15 below the roller 12a. The fixing nip portion N can be formed by a backup member 13b which is a pressure pad on the back surface of the pressure belt 13a in contact with the pressure belt 13a. In this case, oil is applied to the upper fixing member (fixing roller 12a) by the oil application device 21 of the present invention, and oil is applied to the lower pressure member (pressure belt 13a) by the oil application device 22. It becomes like this.

Next, the image forming apparatus according to the present invention will be described.
FIG. 12 shows the configuration of a tandem type color copying machine which is an image forming apparatus according to the present invention.
The color copying machine 200 includes an image forming unit 200A positioned at the center of the apparatus main body, a paper feeding unit 200B positioned below the image forming unit 200A, and an image reading unit (not shown) positioned above the image forming unit 200A. The fixing device 100 described above is incorporated in the image forming unit 200A.

  The image forming unit 200A is provided with a transfer belt 210 having a transfer surface extending in the horizontal direction, and a configuration for forming an image of a color complementary to the color separation color on the upper surface of the transfer belt 210. Is provided. That is, photoconductors 205Y, 205M, 205C, and 205K as image carriers that can carry images of toners of complementary colors (yellow, magenta, cyan, and black) are juxtaposed along the transfer surface of the transfer belt 210. ing.

  Each of the photoconductors 205Y, 205M, 205C, and 205K is configured by a drum that can rotate in the same direction (counterclockwise direction), and around the optical writing device 201 that performs image forming processing in the rotation process, Charging devices 202Y, 202M, 202C and 202K, developing devices 203Y, 203M, 203C and 203K, primary transfer devices 204Y, 204M, 204C and 204K and a cleaning device are arranged. Each developing device 203Y, 203M, 203C, 203K contains a respective color toner.

  The transfer belt 210 is configured to be able to move in the same direction at a position facing the photoconductors 205Y, 205M, 205C, and 205K by being wound around a driving roller and a driven roller. Further, a transfer roller 212 is provided at a position facing a roller 211 that is one of the driven rollers. Further, the conveyance path of the sheet P from the transfer roller 212 to the fixing device 100 is a horizontal path.

  The sheet feeding unit 200B separates the sheet P in the sheet feeding tray 220 one by one from the top in order from the top to the position of the transfer roller 212. It has a transport mechanism for transporting.

  In image formation in the image forming apparatus 200 of the present invention, the surface of the photoreceptor 205Y is uniformly charged by the charging device 202Y, and an electrostatic latent image is formed on the photoreceptor 205Y based on image information from the image reading unit. Is done. The electrostatic latent image is visualized as a toner image by a developing device 203Y containing yellow toner, and the toner image is primarily transferred onto the transfer belt 210 by a primary transfer device 204Y to which a predetermined bias is applied. Is done. The other photoconductors 205M, 205C, and 205K also form similar images only with different toner colors, and the toner images of the respective colors are sequentially transferred onto the transfer belt 210 by the electrostatic force and superimposed.

Next, the toner image T primarily transferred from the photoconductors 205Y, 205M, 205C, and 205K onto the transfer belt 210 is transferred to the sheet P conveyed by the rollers 211 and 212. The sheet P to which the toner image T has been transferred is further conveyed to the fixing device 100 and is fixed at a fixing nip N between the fixing belt 12 and the pressure roller 13. Appropriate amounts of oil are applied to the fixing belt 12 and the pressure roller 13 by oil application devices 21 and 22, respectively, and if necessary, separation claws 16a and 16b disposed on the exit side of the fixing nip N are provided. Therefore, the sheet P is discharged to the exit side of the fixing nip N without being wound around the fixing belt 12 and the pressure roller 13.
Next, the sheet P discharged from the fixing nip N is sent out to the stacker 215 along the discharge path.

  As described above, in the present invention, the image forming apparatus having the fixing device 100 can provide a more advanced fixing separation function, and can reduce various paper types (from thin paper to thick paper) and images (image leading margin). Possible).

  In the image forming apparatus 200, the oil tank 251 that collects oil for improving the releasability of the sheet P used in the fixing apparatus 100 is attached to the fixing apparatus 100, and the oil in the oil tank 251 is fixed again. An oil circulation mechanism such as an oil pump 252 that supplies the apparatus 100 is provided.

FIG. 13 shows a schematic configuration of an oil circulation mechanism provided in the image forming apparatus 200.
The oil circulation mechanism 250 includes an oil tank 251 that holds oil to be used, an oil pump 252 that uses a piezoelectric element, a conveyance path 253 that connects the oil pump 252 to the oil application device 21 of the fixing device 100, and an oil application device. 21, an oil receiver 254 that receives excess oil, a tube 255 that conveys the oil in the oil receiver 254 to the oil application device 22, and a conveyance path 256 that connects the oil application device 22 to the oil tank 251. The oil tank 251, the oil pump 252, the transport paths 253 and 256 are outside the fixing device 100, and the oil receiver 254 and the tube 255 are inside the fixing device 100. The oil tank 251 has an oil near-end sensor 251a that detects the remaining amount of oil inside. As a result, the first oil application device (oil application device 21) that applies oil O to the first nip forming member (fixing belt 12) and the second oil oil that is applied to the second nip formation member (pressure roller 13). 2 Assuming an oil application device (oil application device 22), an oil receiver (oil receiver 254) that collects excess oil O in the oil application device 21 and a supply path for supplying oil O from the oil receiver to the oil application device 22 ( Tube 255), an oil recovery unit (conveying path 256, oil tank 251) for recovering oil O from the oil application device 22, and an oil supply device for supplying the oil O recovered in the oil recovery unit to the oil application device 21 (An oil pump 252 and a conveyance path 253), and an oil circulation mechanism 250 is configured.

  In the image forming apparatus 200, the oil circulation mechanism 250 circulates and uses oil in the above-described path, and the oil application apparatuses 21 and 22 can continuously apply the oil to the fixing belt 12 and the pressure roller 13. .

FIG. 14 shows an oil amount balance in the oil circulation mechanism 250 at this time.
When the image forming process is started, the oil pump 252 from the oil tank 251 storing an amount of oil that does not run out of oil during the maintenance cycle of the image forming apparatus 200, for example, a total amount of 4L of silicone oil, is supplied. The oil is pumped up and transported to the oil application device 21 via the transport path 253, and the oil is supplied at an oil supply amount A from the oil inlet 21a to the oil reservoir 21b (for example, supply of about 3 g / min) Speed).
In the oil application device 21, the amount B1 of oil is supplied from the supply felt 21d to the supply roller 21e, and the remaining B2 overflows from the supply felt 21d. Next, the supply roller 21e scrapes off the amount C2 of oil by the regulation of the metering blade 21f, the remaining C1 passes over the application roller 23, and then the amount D of oil is applied to the fixing belt 12 from the application roller 23. . Then, when the sheet (transfer paper) P passes through the fixing nip N, an amount E of oil adheres to the front surface of the sheet P.
Next, the oil in the overflow (B2) of the supply felt 21d and the oil (C2) scraped off by the metering blade 21f is collected by the oil receiver 254 as surplus oil in the oil application device 21, and is passed through the tube 255. The oil is supplied to the sub oil pan 22a1 of the oil application device 22 on the pressure roller 13 side.
In the oil application device 22, the pressure roller 13 is immersed in the sub oil pan 22a1 and oil is applied. At this time, there is an exchange of oil for the take-out amount (F) and the return amount (I) in the cleaning felt 22c. As a result, the amount G of oil is applied to the pressure roller 13. In the pressure roller 13, the amount H 2 of oil is scraped off by the restriction of the blade 22 b, and the amount H 1 remains on the pressure roller 13. Then, when the sheet (transfer paper) P passes through the fixing nip portion N, the amount H1 of oil adheres to the back surface of the sheet P.
Next, the amount J of oil transferred from the sub oil pan 22a1 to the main oil pan 22a2 is recovered in the oil tank 251 via the transport path 256 as recovered oil (recycled oil).

In the oil circulation mechanism 250 described above, the conditions for establishing oil circulation (relational expression of the oil amount) are as follows.
First, the relational expression of the oil amount balance in the entire oil circulation mechanism 250 is expressed by the following expression (1).
A = J + (E + H1) (1)

Further, the conditional expression for preventing the oil from depleting as the system of the oil circulation mechanism 250 is the following expression (2).
A> J (2)

The conditional expression for the amount of oil necessary to ensure the releasability of the sheet P is the following expression (3).
A> E + H1 (3)

The conditional expression for preventing the oil on the pressure roller 13 side from being depleted is the following expression (4).
B2 + C2> J (4)

  In the image forming apparatus 200, when the fixing device 100 is pulled out of the image forming apparatus 200 and then mounted again in the image forming apparatus 200, an oil charging device (an oil tank 251, an oil pump 252, a transport path). 253) may perform image formation after supplying oil to the oil reservoir 21b of the fixing device 100 and replenishing it. As a result, since the oil level in the oil reservoir 21b is the position of the mouth cut portion 21b1, a sufficient amount of oil can be applied to the fixing belt 12 even immediately after the start of image formation.

  Here, in the oil circulation mechanism 250, solid impurities such as dust and calcium carbonate derived from the sheet P are inevitably mixed in the oil O. If the oil O is circulated with such solid impurities mixed in, the impurities adhere to other functional parts in the oil circulation path, resulting in malfunction or image failure. Therefore, in the conventional oil circulation mechanism, as shown in FIG. 15, an oil filter 252a is provided at the pump suction port of the oil pump 251, and the oil O in the oil tank 251 is filtered by the oil filter 252a to remove solid impurities. In order to prevent such impurities from entering the oil supply path.

However, if pumping by this method is continued, the oil filter 252a is clogged due to adhesion of solid impurities, the pumping amount is reduced, and as a result, the image quality is deteriorated due to insufficient oil supply. There has occurred.
The inventors have grasped that clogging is likely because the oil is being filtered through the small pump inlet of the oil pump 252 while studying this problem, and have made extensive studies to improve the oil circulation mechanism 250. did. Hereinafter, the configuration will be described.

FIG. 16 shows a configuration example of a main part of an image forming apparatus according to the present invention.
An image forming apparatus 200 according to the present invention includes:
(1) A first nip forming member (fixing member (fixing belt 12)) provided rotatably, and a second nip forming member (pressure member (rotating member) provided rotatably below the first nip forming member). The pressure roller 13)) is in contact with the pressure roller 13)) so as to form a fixing nip portion (fixing nip portion N) and holds oil (oil O) and is provided below the second nip forming member. 2 An immersion tank (sub oil pan 22a1) in which a part of the nip forming member is immersed, an oil receiver (main oil pan 22a2) in which the immersion tank is accommodated, and the immersion tank and the oil receiver are disposed ( More specifically, an oil application device (an oil filter 22f) that is disposed in the main oil pan 22a2 and below the sub oil pan 22a1 and that filters oil overflowing from the immersion tank (oil filter 22f). A fixing device comprising a Le application device 22) and (fixing device 100),
(2) An oil circulation mechanism (oil circulation mechanism 250) that supplies oil filtered by the oil filter to the oil application devices (oil application devices 21 and 22) again. Although the fixing device 100 and the oil circulation mechanism 250 are partially omitted, the fixing device 100 is the same as that shown in FIGS. 2, 4 and 9 except for the oil filter 22f, and the oil circulation. The mechanism 250 is the same as that shown in FIG.

  Here, the oil filter 22f is in the form of a sheet having a width equal to or greater than the width of the second nip forming member (pressure member (pressure roller 13)). The oil filter 22f is a compressed sheet made of a fiber (for example, a meta-aramid fiber) that is heat resistant and does not react with the oil, and permeates the oil while capturing fine solid impurities therein. To do. Thereby, it is possible to remove fine solid impurities (for example, dust or calcium carbonate derived from the sheet P) in the oil O while allowing the oil O to pass through the oil tank 22. The material of the oil filter 22f may be the same as the felt used in other parts such as the sheet-like oil scattering prevention member 22d. However, the oil filter 22f has a function of filtering the oil O from them. However, it is necessary to reduce the mesh within a predetermined range (fineness of the eyes).

With the above configuration, the oil O is used in the following route (see FIGS. 13 and 16).
First, the oil O used in the oil application device 22, that is, the oil O overflowing from the sub oil pan 22a1 to the main oil pan 22a2, is filtered by the oil filter 22f, and after removing solid impurities, the main oil pan It is poured into the oil tank 251 from the oil discharge port 22a2 via the transport path 256. Next, the oil O stored in the oil tank 251 is pumped out by the oil pump 252, supplied to the oil reservoir 21 b of the oil application device 21 via the transport path 253, and used for oil application to the fixing belt 12. Is done. Next, surplus oil in the oil application device 21 is collected by the oil receiver 254, and the oil O is supplied to the sub oil pan 22 a 1 of the oil application device 22 on the pressure roller 13 side via the tube 255, and the pressure roller 13. Used for oil application. Then, the oil O used in the oil application device 22 is again filtered by the oil filter 22f, and thereafter the oil O is used by repeating this circulation.

  In the present invention, since the oil filter is not provided directly at the pump suction port portion of the oil pump 252, the pumping amount of the oil pump 252 does not decrease even when used for a long period of time. Further, in the oil tank 22a, the oil O overflowing from the sub oil pan 22a1 is filtered each time by a sufficiently large sheet-like oil filter 22f having a width equal to or larger than the width of the second nip forming member (pressure roller 13). Therefore, even if it is used for a long period of time, it is not clogged, and it is possible to supply a sufficient amount of oil to the oil application apparatuses 21 and 22 while preventing impurities from entering the oil supply path. Therefore, a sufficient amount of oil free from impurities can be applied to the fixing belt 12 and the pressure roller 13, so that good release properties and image quality of the sheet P can be maintained.

  Note that an oil filter 256a that filters oil O to remove impurities by auxiliary oil filtration may be provided at the end of the oil circulation mechanism 250 on the oil tank 251 side on the assumption that the oil filter 22f is disposed. Good. Thereby, the circulated oil O can be used in a state with fewer impurities.

  In addition, the oil tank 251 is provided with a partition 251d that partitions the tank into two parts, a settling tank 251b and a supply tank 251c, and the oil O recovered from the transport path 256 is first put into the settling tank 251b to precipitate solid impurities. After that, it is preferable that the supernatant oil O passing from above the partition 251d is stored in the supply tank 251c, and the oil pump 252 is pumped up from the supply tank 251c. This is preferable because impurities are further removed in the precipitation tank 251b.

  Although the present invention has been described with the embodiments shown in the drawings, the present invention is not limited to the embodiments shown in the drawings, and other embodiments, additions, changes, deletions, etc. Can be changed within the range that can be conceived, and any embodiment is included in the scope of the present invention as long as the effects and advantages of the present invention are exhibited.

FIG. 10 is a cross-sectional view illustrating a configuration of a conventional fixing device. FIG. 2 is a cross-sectional view illustrating a configuration of a fixing device according to the present invention. It is sectional drawing which shows the structure of the oil application apparatus by the side of the conventional fixing member. It is sectional drawing which shows the structure of the 1st oil application apparatus in the fixing device which concerns on this invention. It is a perspective view which shows the principal part structure of the 1st oil application apparatus used by this invention. It is sectional drawing which shows the other structural example (1) of the 1st oil application | coating apparatus used by this invention. It is sectional drawing which shows the other structural example (2) of the 1st oil application | coating apparatus used by this invention. It is sectional drawing which shows the structure of the oil application apparatus by the side of the conventional pressurization member. It is sectional drawing which shows the structure of the 2nd oil application | coating apparatus in the fixing device which concerns on this invention. It is a top view which shows the structure of the 2nd oil application | coating apparatus in the fixing device which concerns on this invention. FIG. 6 is a cross-sectional view showing another configuration example of a pressure member and a fixing member in the fixing device according to the present invention. 1 is a cross-sectional view illustrating a configuration of an image forming apparatus according to the present invention. It is the schematic which shows the structure of the oil circulation mechanism in the image forming apparatus of FIG. It is the schematic which shows the relationship of the oil quantity balance of the oil circulation mechanism in the image forming apparatus which concerns on this invention. It is the schematic which provides an oil filter in the pump inlet of an oil pump, and is an oil circulation mechanism. It is the schematic which shows another structure of the oil circulation mechanism in the image forming apparatus which concerns on this invention.

Explanation of symbols

11, 12a, 84 Fixing roller 12, 92 Fixing belt 13, 85 Pressure roller 13a Pressure belt 13b Backup member 13h, 14h, 86, 87 Heater 14, 83 Heating roller 14a Heat pipe 15 Tension roller 16a, 16b Separation claw 17 Cleaning mechanism 21, 21A, 21B, 22, 71 Oil coating device 21a, 71a Oil inlet 21b Oil reservoir 21b1 Opening portion 21b2 Gutter 21b3 Side plate 21c Support plate 21d, 71d Supply felt 21e Supply roller 21f Metering blade 22a Oil Tank 22a1 Sub oil pan (immersion tank)
22a2 Main oil pan (oil receiver)
22b Blade 22c Cleaning felt 22d Oil scattering prevention member 22f, 252a, 256a Oil filter 23, 23 ', R1 Application roller 71b Oil receiver 71c Oil transmission hole 96 Oil pan 100 Fixing device 100c Fixing cover 200 Image forming device 200A Image forming portion 200B Feeder 201 Optical writing device 202Y, 202C, 202M, 202K Charging device 203Y, 203M, 203C, 203K Developing device 204Y, 204M, 204C, 204K Primary transfer device 205Y, 205C, 205M, 205K Photoconductor 210 Transfer belt 211 Followed Roller 212 Transfer roller 215 Stacker 220 Paper feed tray 250 Oil circulation mechanism 251 Oil tank 251a Oil near end sensor 251b Sedimentation tank 25 Receiving c supply tank 251d partition 252 oil pump 253 and 256 transport path 254 Oil 255 Tube O Oil P sheet (recording medium)
R1 Application roller R3 Oil application functional parts R11, R14, R15 Roller T Toner

Claims (4)

A first nip forming member provided rotatably,
A second nip forming member rotatably provided below the first nip forming member is disposed so as to contact the second nip forming member so as to form a fixing nip portion;
A first oil application device for applying oil to the first nip forming member;
A second oil application device for applying oil to the second nip forming member;
An oil receiver for collecting excess oil in the first oil application device;
A supply path for supplying oil from the oil receiver to the second oil application device;
An oil recovery section for recovering oil from the second oil application device;
An oil supply device for supplying the oil recovered in the oil recovery unit to the first oil application device ,
The amount of oil supplied to the first oil application device is A, the amount of oil recovered by the oil recovery unit is J, the amount of oil applied to the surface of the transfer paper on the first nip forming member side is E, and the first amount of transfer paper is the first. When the amount of oil applied to the surface on the 2-nip forming member side is H1, and the amount of excess oil collected by the oil receiver is K, the following equations (1) to (4)
A = J + (E + H1) (1)
A> J (2)
A> E + H1 (3)
K> J (4)
An image forming apparatus satisfying the requirements . The first oil application device includes an oil application unit that applies oil to the first nip forming member , and an oil supply unit that supplies oil to the oil application unit,
The oil supply unit is disposed adjacent to an oil input port for supplying oil, an oil storage unit for storing oil supplied from the oil input port, and a lower side of the oil storage unit. A supply felt in which oil is supplied to the part and oil overflowing from the upper part of the oil reservoir part is supplied, and in the width direction of the oil reservoir part, from the inside of the recess of the oil reservoir part to an area other than the oil inlet The image forming apparatus according to claim 1 , further comprising: a hollow felt connected to the supply felt . The second oil application device includes a dipping tank that holds oil and is provided below the second nip forming member and in which a part of the second nip forming member is immersed, and a second nip formation than the dipping tank. An oil regulating member provided on the downstream side of the rotation of the member and before the fixing nip portion to regulate the amount of oil adhering to the second nip forming member, and further downstream of the second nip forming member than the immersion tank. The image forming apparatus according to claim 1 , further comprising: a cleaning member that abuts on the upstream side of the rotation of the second nip forming member relative to the oil regulating member and cleans the surface of the second nip forming member . The second oil coating apparatus, an immersion tank part is immersed in the second nip forming member is to hold the oil provided below the second nip forming member, the entire the immersion tank is housed, oil The image forming apparatus according to claim 1, further comprising: an oil receiver provided with an oil discharge port to the collection unit; and an oil filter that is disposed between the immersion tank and the oil receiver and filters oil overflowing from the immersion tank. apparatus.

Images