JP2007047450A - Fixing device and image forming apparatus mounted with same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing device and an image forming apparatus which have high image quality by not using silicon oil to avoid trouble caused by it, and using wax-containing toner instead to prevent luster memory and eliminate left striped unevenness. <P>SOLUTION: The fixing device that conveys and nips a transfer material to which a toner image containing wax is transferred at a fixation nip part provided between a heated fixing rotary body and a pressure member to thermally fix the toner image is provided with a cleaning unit, which cleans the surface of the fixing rotary body and comprises a cleaning rotary body coming into contact with the fixing rotary body and a cleaning member coming into contact with the cleaning rotary body, upstream in the rotating direction of the fixing rotary body, and also provided with a wax leveling member which comes into contact with the fixing rotary body downstream from the cleaning unit and upstream from the fixation nip part. The surface roughness of the wax leveling member is made smaller than larger surface roughness between the cleaning rotary body and cleaning member. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fixing device used in an image forming apparatus such as an electrophotographic method or an electrostatic recording method, and an image forming apparatus including the fixing device.

  Usually, a fixing device used in an image forming apparatus such as an electrophotographic method forms a fixing nip portion by, for example, a fixing roller and a pressure roller, and fixes a transfer material carrying toner at the fixing nip portion.

  Conventionally, an offset that causes toner to adhere to the surface of the fixing roller at the time of this fixing occurs, or the paper carrying the toner on the fixing roller is wound, thereby reducing the image quality and the paper passing performance. Although a problem has occurred, for example, a technique of suppressing the occurrence of offset and paper wrapping by applying silicone oil to the surface of the fixing roller has been used.

  However, in the conventional technique of using silicone oil for the fixing roller, the silicone oil of the fixing roller adheres to the transfer paper, and the sticky feeling due to the silicone oil adhesion cannot be avoided, and there is a big problem in the quality of the obtained image. It is left. In addition to expensive silicone oil, it is necessary to provide a mechanism for supplying silicone oil to the fixing device in the apparatus. Further, there is a problem that a part of the silicone oil evaporates due to heat and the inside of the machine is contaminated.

Therefore, as in the past, the use of silicone oil or the like on the fixing roller is suppressed as much as possible, and instead of using a toner to which wax is added, the wax dissolved from the toner during heating is supplied to the fixing roller. A technique for suppressing sticking is disclosed. (For example, see Patent Document 1)
However, when wax adheres to the fixing rotator, a wax latent image is formed by the wax and appears as uneven gloss in the next image. In order to avoid this, there is a technique (see, for example, Patent Document 2) in which a cleaning rotator is brought into contact with the fixing rotator and a cleaning web as a cleaning member is further brought into contact with the contact rotator. Even when various measures are taken, streaky irregularities of wax appear on the image.
JP-A-3-185459 JP 2005-43532 A

  By fixing using toner added with wax in this way, it is possible to suppress the use of silicone oil, and to prevent the occurrence of offset and paper wrapping. It is also possible to suppress the occurrence of glossy memory due to the latent wax image formed on the fixing roller. However, as an additional problem, it remains unsolved that streaky unevenness of the wax appears on the image and degrades the image quality.

  The present invention has been made in view of such problems, and an object of the present invention is to eliminate the use of silicon oil, avoid the obstacle, and use wax-containing toner instead to prevent the occurrence of gloss memory. Another object of the present invention is to provide a fixing device and an image forming apparatus having high image quality by eliminating the remaining streaky unevenness.

  This object is achieved by any one of the following technical means (1) to (6).

(1) A transfer material onto which an unfixed image formed using a toner containing wax is transferred is transported to a fixing nip portion provided between a heated fixing rotator and a pressure member to be thermally fixed. A fixing device,
A cleaning unit for cleaning dirt on the surface of the fixing rotator is provided on the upstream side in the rotation direction of the fixing rotator to be thermally fixed in contact with the toner image on the transfer material, and on the downstream side of the fixing nip portion. Provided on the upstream side is a wax uniformizing member in contact with the fixing rotator,
The cleaning unit includes a cleaning rotator that contacts the fixing rotator, and a cleaning member that contacts the cleaning rotator.
The fixing device according to claim 1, wherein a surface roughness Rz of the wax uniformizing member is made smaller than a larger surface roughness Rz of the cleaning rotator and the cleaning member.

  (2) The fixing device according to item (1), wherein the wax uniformizing member is a rotating roller.

  (3) The fixing device according to (1), wherein the wax uniformizing member is a rotating roller with a built-in heater.

  (4) The fixing device according to item (1), wherein the wax uniformizing member is a plate-like blade having elasticity.

  (5) The surface roughness Rz of the larger of the cleaning rotating body and the cleaning member is 4.0 μm or less, and the surface roughness Rz of the wax uniformizing member is 1.6 μm or less. The fixing device according to any one of (1) to (4).

  (6) An image forming apparatus comprising the fixing device according to any one of (1) to (5).

  The present invention eliminates the use of silicone oil, avoids its obstacles, uses wax-containing toner instead, prevents the occurrence of glossy memory, eliminates remaining streaky irregularities, and is high A fixing device and an image forming apparatus having image quality can be provided.

  Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited thereto. In addition, the following description may include affirmative expressions for terms and the like, but it shows preferred examples of the present invention and limits the meaning and technical scope of the terms of the present invention. It is not a thing.

  FIG. 1 is a schematic view showing an example of an image forming apparatus of the present invention.

  As shown in FIG. 1, the image forming apparatus 1 is called a tandem color image forming apparatus, and includes a plurality of sets of image forming units 9Y, 9M, 9C, and 9K, and a belt-like intermediate transfer member 6 and a supply. The paper unit, the conveyance unit, the toner cartridges 5Y, 5M, 5C, and 5K, the fixing device 10 according to the present invention, the operation unit 91, and the like are included.

  An image forming unit 9Y that forms a yellow image includes a charging unit 2Y, an exposure unit 3Y, a developing unit 4Y, a transfer unit 7Y, and a cleaning unit 8Y arranged around an image carrier (hereinafter referred to as a photoreceptor) 1Y. Have

  The image forming unit 9M that forms a magenta image includes a photoreceptor 1M, a charging unit 2M, an exposure unit 3M, a developing device 4M, a transfer unit 7M, and a cleaning unit 8M.

  The image forming unit 9C that forms a cyan image includes a photoreceptor 1C, a charging unit 2C, an exposure unit 3C, a developing device 4C, a transfer unit 7C, and a cleaning unit 8C.

  The image forming unit 9K that forms a black image includes a photoreceptor 1K, a charging unit 2K, an exposure unit 3K, a developing device 4K, a transfer unit 7K, and a cleaning unit 8K.

  The intermediate transfer body 6 is wound around a plurality of rollers 6A, 6B, and 6C and is rotatably supported.

  Each color image formed by the image forming units 9Y, 9M, 9C, and 9K is sequentially primary-transferred onto the rotating intermediate transfer body 6 by the transfer means 7Y, 7M, 7C, and 7K, and the combined color image. Is formed.

  The paper P stored in the paper feed cassette 20 as the paper feed means is fed one by one by the paper feed roller 21, is conveyed to the transfer means 7 A through the registration roller 22, and the color image is transferred onto the paper P. Is secondarily transferred.

  The paper P on which the color image has been transferred is fixed by the fixing device 10 which is the fixing device of the present invention, and is sandwiched by the paper discharge roller 25 through the transport rollers 23 and 24 which are transport means, and is discharged outside the machine. It is placed on the paper tray 26.

  FIG. 2 is a schematic sectional view of the fixing device 10 for explaining the fixing device of the present invention in detail.

  As shown in FIG. 2, the fixing device 10 of the present invention has a heat fixing roller 101 which is a fixing rotating body according to the present invention. Further, the fixing device 10 includes a cleaning roller 103 which is a cleaning rotating body according to the present invention and a cleaning web 104 which is a cleaning member according to the present invention, and removes the wax adhering to the heat fixing roller 101 with these.

  The heat fixing roller 101 is a pressure rotator, and forms a fixing nib portion N with the pressure roller 102 in pressure contact with the heat fixing roller 101, and passes the transfer material P having the toner t through the fixing nip portion N to heat Fixing is in progress. By heat fixing at the nip portion N, the toner t is melted and fixed on the transfer material P. At this time, the wax dispersed and contained in the toner t is melted and exists in a predetermined amount or more at the interface between the heat fixing roller 101 and the melted toner resin, so that the adhesive force between the toner resin and the heat fixing roller 101 is increased. The offset and the winding of the transfer material are suppressed, and a part of the wax adheres to the heat fixing roller 101.

  The heat fixing roller 101 is a silicone rubber having a heat conductivity of 0.50 W / m · K, a JIS-A hardness of 10 °, and a thickness of 1.5 mm on a cylindrical core metal 105 made of aluminum A5056 containing a halogen heater 161 as a heat source. The heat-resistant elastic layer 106 is formed, and the toner release layer 107 of PFA resin having a thickness of 30 μm is applied on the outermost surface via one to three adhesive layers, and a dispersion-state PFA resin is applied and baked. By doing so, it is formed and is rotationally driven by a motor (not shown). The heat fixing roller 101 may be covered with a PFA tube molded as a tube as a PFA resin toner release layer 107 on the heat-resistant elastic layer 106 via an adhesive layer or the like.

  The toner release layer 107 is preferably made of a material containing a fluororesin. More preferred as the fluororesin is a material containing any of PFA, PTFE, and FEP, and most preferred is any of PFA, PTFE, and FEP. As a result, the releasability of the surface of the heat fixing roller 101 with respect to the wax contained in the toner resin or toner particles is also improved, and it becomes difficult for the toner to adhere to the surface of the heat fixing roller 101 at the time of fixing, and the surface of the heat fixing roller 101 is difficult to adhere to the wax. Thus, even if wax adheres to the surface of the heat fixing roller 101, the effect of removing the wax by the cleaning roller 103 can be further improved, and the gloss memory can be further suppressed.

  The thickness of the toner release layer 107 of the heat fixing roller 101 is preferably 20 to 50 μm. By setting it to 20 μm or more, it becomes easy to form a uniform fluororesin layer. Further, when the thickness is 50 μm or less, the surface of the heat fixing roller 101 can easily follow the surface unevenness of the transfer material P carrying the toner image t, and image deterioration can be suppressed. Further, in the region of 50 μm or less, the surface of the heat fixing roller 101 can easily follow the surface of the cleaning roller 103, so that the effect of removing the wax by the cleaning roller 103 can be further improved.

  The pressure roller 102 has a heat-resistant elastic layer 109 of silicone rubber having a thickness of 1.0 mm formed on an aluminum cylindrical metal core 108, and further has a thickness of 30 μm on the outermost surface through one to three adhesive layers. The toner release layer 110 of PFA resin is formed, and the transfer paper P having the toner image t is pressure-bonded to the heat-fixing roller 101 and rotated while being pressed. The toner release layer 110 is formed by the same method as the toner release layer 107 described above.

  The cleaning roller 103 performs anodizing treatment on the aluminum cylindrical core bar to form an alumina coating, and further performs secondary electrolysis in an ammonium tetrathiomolybdate solution to deposit molybdenum disulfide in ultrafine pores in the coating. Then, the surface is polished, the surface roughness Rz is 1.6 μm or less, and the Vickers surface hardness is 3430 MPa or more. In addition, a halogen heater can be installed inside the aluminum cylinder of the cleaning roller 103 to also serve as an external heating roller.

  As the material of the portion of the cleaning roller 103 that comes into contact with the heat fixing roller 101, any material having a surface roughness Rz of 1.6 μm or less and having heat resistance against the surface temperature of the heat fixing roller 101 can be used. Good. Other than the above, for example, an aluminum cylindrical core metal is molded with a foamed silicone rubber with a thickness of about 3 to 8 mm so that the Asker-C (4.9 N load) hardness is 15 to 50 °, and further You may use what covered the polyimide seamless tube shape | molded so that surface roughness Rz might be set to 1.6 micrometers or less through the adhesive layer etc. on the top about 50-80 micrometers.

  In the present invention, the surface roughness Rz means a value having a reference length of 0.8 mm described in JIS B0601-1982. That is, it is the difference between the average height of the top five peaks and the average height of the bottom five valleys over a distance of the reference length of 0.8 mm.

  The surface roughness Rz of the cleaning roller 103 is particularly preferably 1.0 μm or less. When the temperature equal to or higher than the melting point of the wax is maintained on the heat-fixing roller 101, the wax is in a liquid state and usually has a height of about 1 μm or less. Therefore, the surface roughness Rz is set to a small value as described above. As a result, the contact between the wax and the cleaning roller 103 is further ensured, so that the wax adhering to the heat fixing roller 101 can be wiped off more efficiently.

  The cleaning roller 103 is in contact with the heat fixing roller 101 with a load of 19.6 to 98 N, and the temperature at the contact portion is higher than the melting point of the wax contained in the toner by adjusting the halogen heater 161. I am doing so. As a result, the cleaning roller 103 wipes off the wax adhering to the heat fixing roller 101, improving the wax removal efficiency from the heat fixing roller 101 and suppressing gloss memory.

  The contact portion between the cleaning roller 103 and the heat fixing roller 101 is preferably equal to or larger than the maximum sheet width of the transfer material P used for image formation. In addition, the contact portion between the cleaning web 104 and the cleaning roller 103 is also preferably equal to or greater than the maximum sheet width of the transfer material P used for image formation. This eliminates the gloss memory for any size paper.

  The cleaning roller 103 is also in contact with the cleaning web 104, and the temperature at the contact portion between the cleaning roller 103 and the cleaning web 104 is contained in the toner by the heat from the heat fixing roller 101 heated by the halogen heater 161. It is higher than the melting point of the wax. As a result, the wax adhering to the heat fixing roller 101 is wiped off by the cleaning web 104 in a dissolved state by wiping off the wax adhering to the heat fixing roller 101, and the wax removal efficiency from the cleaning roller 103 is improved. Can be made. The melting point of the wax contained in the toner is usually as low as about 110 ° C. or less, and the heat fixing roller 101 is always supplied with heat from the halogen heater 161 and the surface temperature is usually kept at about 160 ° C. or more. Since 101 and the cleaning roller 103 rotate in contact with each other, the temperature at the contact portion between the cleaning roller 103 and the cleaning web 104 is also higher than the melting point of the wax.

  For example, in the cleaning roller 103 in which an alumina coating is formed and polished on an aluminum cylindrical metal core, the surface temperature immediately rises due to the contact with the heat fixing roller 101 because the thermal conductivity of the metal core is good. As for the thickness of the aluminum cylindrical metal core, it is preferable that the thickness of the aluminum cylindrical core metal is as thin as possible in a range in which no bending occurs, and the surface temperature is quickly increased. Also, in the case of the cleaning roller 103 in which a polyimide tube is covered with the surface of the foamed silicone rubber, the surface temperature immediately rises due to the contact rotation with the heat fixing roller 101 because the thermal conductivity of the foamed silicone rubber is poor.

  The heating and fixing roller 101 and the cleaning roller 103 are preferably provided with a period for rotation during warm-up, whereby the cleaning roller 103 can have a sufficiently high temperature even immediately after the image forming apparatus is started up.

  The heat fixing roller in contact with the cleaning roller 103 with a contact angle at a predetermined temperature T (° C.) of the melting point to 230 ° C. or less with respect to the wax contained in the toner on the surface portion of the cleaning roller 103 in contact with the heat fixing roller 101 When the contact angle at the predetermined temperature T (° C.) for the wax contained in the toner on the surface portion 101 is B, it is preferable that A <B. By doing so, the wax having a melting point or higher adhering to the heat fixing roller 101 at the contact portion between the heat fixing roller 101 and the cleaning roller 103 can easily move from the heat fixing roller 101 to the cleaning roller 103, The wax removal efficiency from the fixing roller 101 is further improved, and the gloss memory can be further suppressed. The above-mentioned temperature range in which the contact angle relationship needs to be maintained is equal to or higher than the melting point of the wax and the maximum temperature in the normal use state of the surface of the fixing rotator (the fluororesin on the surface of the fixing rotator is sufficiently durable). A certain temperature) or less.

  The heat-resistant elastic layer 106 of the heat-fixing roller 101 has a thickness of 0.2 mm or more. Further, the cleaning roller 103 has a Vickers surface hardness of 3430 MPa or more at a portion in contact with the heat-fixing roller 101. It is preferable that the heat fixing roller 101 is in pressure contact with a load of 6 to 98 N. By setting the thickness of the heat-resistant elastic layer 106 of the heat fixing roller 101 to 0.2 mm or more, the surface of the heat roller can easily follow the surface unevenness of the transfer material P carrying the toner image t, and the image quality is improved. Even if the cleaning roller 103 is hard, the contact between the cleaning roller 103 and the heat fixing roller 101 is stable, and the wax adhering to the heat fixing roller 101 at the contact portion between the heat fixing roller 101 and the cleaning roller 103 is heated by the heat fixing roller. It becomes easy to move from 101 to the cleaning roller 103, and the wax removal efficiency from the heat-fixing roller 101 is further improved, and the gloss memory can be further suppressed.

  In addition, by setting the Vickers hardness to 3430 MPa or more, it is possible to suppress the generation of abrasion powder due to the cleaning web 104 with which the cleaning roller 103 abuts or the paper powder adhering thereto, or the surface roughness of the cleaning roller from becoming rough. Therefore, the cleaning effect of the cleaning roller 103 can be maintained.

  Since the cleaning roller 103 is in pressure contact with the heat-fixing roller 101 with a load of 19.6 to 98 N, the contact between the cleaning roller 103 and the heat-fixing roller 101 above the melting point is stable, and the cleaning web 104 is in contact. However, the cleaning roller 103 can be stably driven by the heat fixing roller 101 and does not damage the heat-resistant elastic layer of the heat fixing roller 101.

The Vickers surface hardness is a hardness that can be measured according to the micro hardness test method of JIS Z 2251. Specifically, a diamond regular quadrangular pyramid indenter with a diagonal angle of 136 degrees is used, and the load F (kgf) when the test surface is recessed is divided by the surface area obtained from the diagonal length d (mm) of the recess. Good quotient,
Surface hardness (Hv) = 1.8544 F / d ²
(However, d is the average (mm) of the diagonal length of the depression.)
It can be calculated by In this invention, it is set as the value measured in the environment of 23 degreeC and 50% RH using MVK-H100 (made by Akashi Co., Ltd.).

The cleaning web 104 is in the form of a sheet, and is a nonwoven fabric in which aromatic polyamide fibers and polyester fibers are combined at a mass ratio of 6: 4 to a thickness of 70 μm and a basis weight of 27 g / m ² . The cleaning web 104 may be a non-woven fabric in which an aromatic polyamide fiber and a polyester fiber are combined at a mass ratio of 4: 6 to a thickness of 46 μm and a basis weight of 27 g / m ² .

  For example, when the cleaning web 104 is not used, wax accumulates on the cleaning roller 103 or toner or paper powder that is slightly offset on the heat fixing roller 101 accumulates, so that the wax on the cleaning roller 103 is gradually cleaned. Although the capability is reduced, by providing the cleaning web 104, it is possible to more efficiently wipe off the toner, paper powder, and wax adhering to the cleaning roller 103, so that the cleaning effect can be maintained and improved.

  Any material may be used for the cleaning web 104 as long as it can wipe off the wax having a melting point or higher from the cleaning roller 103, but from the viewpoint of heat resistance, a nonwoven fabric containing an aromatic polyamide fiber or a polyester fiber. Is preferably used.

  The cleaning web 104 is arranged with tension between the original winding side 112A and the winding side 112B, which is the cleaning member moving means according to the present invention, and is arranged so that the cleaning roller 103 comes into contact with the cleaning web 104 and is driven. The cleaning web 104 is moved by rotating a shaft of the winding side 112B of the sheet-like cleaning web by a predetermined angle using a motor (not shown). As a result, the cleaning roller 103 is cleaned by the cleaning web 104 to move the contaminated portion, and the cleaning roller 103 is prevented from accumulating a large amount of toner, paper dust, and wax at the contact portion between the cleaning web 104 and the cleaning roller 103. Cleaning can be performed, and the occurrence of glossy memory can be further suppressed. It is efficient and preferable that the moving amount of the cleaning web 104 is a constant value in the range of 0.02 to 0.05 mm / copy (A3 paper). By setting it to 0.02 mm / copy or more, the cleaning roller 103 is sufficiently cleaned, and by setting it to 0.05 mm / copy or less, it is not necessary to lengthen the length of the cleaning web 104 more than necessary. From the viewpoint of

  The amount of movement of the cleaning web 104 is fixed by setting the driving time of the cleaning web drive motor to a value calculated by an expression that is a function of the accumulated driving time of the cleaning web drive motor from the state where the new cleaning web 104 is attached. It is possible to control to a value.

  Silicone oil is not applied to the heat fixing roller 101. By doing so, the image quality can be further improved and the cost can be reduced.

  Further, the cleaning web 104 is not impregnated with silicone oil. As a result, the image quality can be further improved and the cost can be reduced.

  Now, using wax-containing toner in this way, offset transfer to the image and the stickiness of silicone oil to the image surface can be eliminated without applying silicone oil, and it can be generated by using wax-containing toner. The glossy memory that was there was also removed.

  As long as the toner used in the present invention contains a wax, a conventionally known toner can be used.

  In the present invention, the wax includes, for example, paraffin wax, polyolefin wax, modified products thereof (for example, oxides, graphs and processed products), higher fatty acids, and metal salts thereof, amide waxes, ester waxes, and the like. Conventionally known waxes can be used, but for example, higher fatty acid ester waxes are preferably used. As a result, the exudation of the wax from the toner image portion at the fixing nip portion can be made better and the occurrence of offset and paper entrainment can be further suppressed, and the wax wiping on the cleaning roller 103 becomes better. Further gloss memory can be prevented.

  The wax content of the toner according to the present invention is preferably 7 to 23% by mass. By setting the content of the wax to 7% by mass or more, it is possible to sufficiently exude the wax from the toner image at the fixing nip portion, and it is possible to further suppress the occurrence of offset and paper entrainment. On the other hand, when the wax content is 23% by mass or less, it is possible to further suppress excessive wax adhesion to the heat fixing roller 101.

  Polymerized toner is an example of a toner whose wax content can be easily adjusted. The toner used in the present invention is preferably a polymerized toner because the wax content can be easily adjusted.

  The melting point of the wax contained in the toner according to the present invention is preferably 75 to 110 ° C. As a result, since the wax exudes from the toner image at the fixing nip portion and the wax dissolves smoothly at the contact portion between the heat fixing roller 101 and the cleaning roller 103, the occurrence of offset and paper entrainment is further suppressed. In addition to the ability to wipe the wax with the cleaning roller 103, the gloss memory can be further prevented.

  The toner used for the test was adjusted to a wax content of 7 to 23% by mass, and a toner for a color composite machine Konica 9331 (manufactured by Konica Minolta) was used. This toner is a polymerized toner obtained by an emulsion polymerization method described in detail in JP-A-2004-54240. The used toner has a softening point of about 120 ° C. when the wax content is about 13% by mass, the wax contained in the toner is a higher fatty acid ester wax, and its melting point is about 80 ° C. Here, the softening point refers to a temperature measured using a Koka type flow tester. The melting point of the wax refers to the temperature at the top of the peak showing the maximum endotherm in the DSC curve at the time of temperature increase in differential scanning calorimetry (DSC).

  However, as a new problem, there is a problem of the occurrence of a streak failure. It has become necessary to eliminate this problem and to obtain a stable high-quality image. In the present invention, a high-quality image can be stably formed without worrying about the occurrence of streak failure by forming an image using the fixing device described below and an image forming apparatus equipped with the wax-containing toner. It became so. This will be described in detail below.

The image forming apparatus and the fixing device shown in FIGS. 1 and 2 are used, and as shown in Table 1, each of the cleaning roller 103 and the cleaning web 104 as the cleaning unit 103A is manufactured with eight types of roughness Rz. In addition, four types of wax equalizing members were prepared, and using the above-described toner t prepared in this example and 81.4 g / m ² paper (A4 size) using a cleaning roller, toner adhesion on the paper A full color image is formed so that the amount is about 0.4 to 0.5 mg / cm ² per color, image formation of 101 continuous image samples is performed, and the transfer speed of the transfer material P is described later. A total of 800 image samples 1 to 8 were produced, each of which was carried out at three levels of 73, 110, and 220 mm / s.

  Table 1 is for a speed level of 220 mm / s. 73 and 110 mm / s were also tested in the same manner as 220 mm / s, and the same results as in Table 1 were obtained.

  2 are used for the heat fixing roller 101 and the pressure roller 102 of the fixing device 10 shown in FIG.

  As described above, the heat fixing roller 101 has a heat-resistant elastic layer 106 made of silicone rubber having a thermal conductivity of 0.50 W / m · K and a JIS-A hardness of 10 ° on a cylindrical core of aluminum A5056 having a thickness of 1.5 mm. Further, a toner release layer 107 of PFA resin having a thickness of 30 μm is formed on the uppermost surface via two adhesive layers, and the surface smoothness is formed by applying and baking the PFA resin in a dispersion state. What processed and was made into the outer diameter 65.0mm, and the surface roughness Rz used what is 2.0 micrometers or less.

  As described above, the pressure roller 102 also has a heat-resistant elastic layer 106 made of silicone rubber having a thermal conductivity of 0.50 W / m · K and a JIS-A hardness of 10 ° on a cylindrical core of aluminum A5056, having a thickness of 1.0 mm. Further, a toner release layer 107 of PFA resin having a thickness of 30 μm is formed on the outermost surface via two adhesive layers by applying and baking a dispersion-state PFA resin, and having an outer diameter What was 55.0 mm and the surface roughness Rz was 2.0 micrometers or less was used.

  The pressure-bonding load between the heat fixing roller 101 and the pressure roller 102 is about 980 N, and the nip width is about 7 to 8 mm. By driving the heat-fixing roller, the transfer speed of the transfer material P is set to a predetermined speed. In this embodiment, as described above, there are three levels of 73 mm / sec, 110 mm / sec, and 220 mm / sec. Passing through paper. A halogen heater 161 is fixedly installed inside the aluminum cylindrical core of the heat fixing roller 101, and is detected by a temperature detection sensor (not shown) disposed at a position close to the surfaces of the heat fixing roller 101 and the pressure roller 102. By performing ON / OFF control by output, the surface temperature of the heat fixing roller 101 is set to a predetermined value within a range of 160 to 210 ° C., and the surface temperature of the pressure fixing roller 102 is set to a predetermined value within a range of 140 to 190 ° C. I try to keep it.

In this way, the inventor uses the above-mentioned toner containing wax as a transfer material on which a developed unfixed image has been transferred, as a fixing roller 101 as a heated fixing rotator, and as a pressure member. A fixing device for carrying out a heat nip by conveying a nip to a fixing nip portion N provided between the pressure rollers 102;
A cleaning unit 103 for cleaning dirt on the surface of the fixing roller 101 is provided on the upstream side in the rotation direction of the fixing roller 101 to be thermally fixed in contact with the toner image on the transfer material P, and on the downstream side and the fixing nip. Provided on the upstream side of the portion N is a wax uniformizing member 121 in contact with the fixing roller 101,
The cleaning unit 103 </ b> A includes a cleaning roller 103 as a cleaning rotary member that contacts the heat fixing roller 101 as the fixing rotary member, and a cleaning web 104 as a cleaning member that contacts the cleaning roller 103.
The wax uniformizing member 121 has a surface roughness Rz smaller than the larger surface roughness Rz of the cleaning roller 103 as the cleaning rotating body and the cleaning web 104 as the cleaning member. .

  Using the fixing device 10 of the present invention configured as shown in FIG. 2, the fixing roller 101, the cleaning roller 103, the cleaning web 104, and the wax equalizing member 121 under the hardness and material specification conditions of the above-described embodiment. Each of these was processed for surface roughness and tested for fixing performance.

  The main test item is the occurrence of streaky wax unevenness and its level check. The results are shown in Table 1. The criteria for determination were based on the level of streaky wax unevenness as follows.

  Level 1 In all samples, streaky wax unevenness occurs remarkably.

  Level 2 All samples show slight streaky wax unevenness.

  Level 3 Slight streaky wax unevenness occurs in some samples.

  Level 4 No streaky wax unevenness occurs.

      Level 1 is not possible, and levels 2, 3, and 4 are acceptable levels.

  The sample 1 satisfies the present invention with respect to the magnitude relationship between the surface roughnesses of the fixing roller 101, the cleaning roller 103, the cleaning web 104, and the wax uniformizing member 121, but the surface roughness. However, as Samples 2, 3, and 4 were made, the surface roughness was reduced, and the occurrence of streaky wax unevenness decreased. There will be nothing.

  Thus, the larger surface roughness Rz of the cleaning roller 103 and the cleaning web 104 is 4.6 μm or less, preferably 4.0 μm or less, more preferably 1.0 μm or less, with a margin. The surface roughness Rz of the wax uniformizing member 121 is further reduced.

  As described above, Table 1 shows a speed level of 220 mm / s, but 73 and 110 mm / s were tested in the same manner as 220 mm / s, and the same results as in Table 1 were obtained.

  It was also confirmed that there was no gloss memory for Samples 2, 3, and 4.

  Furthermore, although the wax uniform member 121 is of a roller type in the above embodiment, a blade type member of the same hardness or material may be used although not shown.

  Next, FIG. 3 shows a schematic diagram of another example of the fixing device of the present invention.

  The fixing device shown in FIG. 3 supports a fixing belt 121A, which is a fixing rotating body according to the present invention, by an upper pressure roller 122 and a supporting heating roller 123, and the supporting heating roller 123 is rotated by a motor (not shown). The fixing belt 121A is driven to rotate. The fixing belt 121 is heated by a support heating roller 123.

  In the fixing device 10 shown in FIG. 3, a nip portion N is formed by a fixing belt 121 </ b> A supported by a supporting pressure roller 122 and a supporting heating roller 123 and a lower pressure roller 124. Heat transfer is performed by passing the transfer material P having t.

  Further, the cleaning roller 103 having the halogen heater 162 therein is provided in contact with the fixing belt 121A, and the cleaning web 104 is provided in contact with the cleaning roller 103. Further, the wax uniformizing member 121 is brought into contact with the support heating roller 123 via the fixing belt 121A.

  In the present invention, as shown in FIG. 3, even when the fixing rotating body according to the present invention is the fixing belt 121A, the temperature of the contact portion between the fixing belt 121A and the cleaning roller 103, the cleaning roller 103, The temperature of the contact portion with the cleaning web 104 is set higher than the melting point of the wax contained in the toner to be used, and the wax on the fixing belt 121A is wiped off in a molten state by the cleaning roller 103 and further adhered to the cleaning roller 103. The cleaning web 104 is wiped off in a molten state, and the larger one of the cleaning roller 103 and the cleaning web 104 has a surface roughness Rz of 4.6 μm or less and a margin of 4.0 μm or less. Preferably, it is 1.0 μm or less. As a result, the occurrence of gloss memory can be suppressed, and by making the wax uniformizing member 121 have a lower surface roughness Rz, streaky wax unevenness is eliminated, and there is almost no fear of using wax toner.

  In the fixing device 10 illustrated in FIG. 3, the halogen heater 161 of the support heating roller 123 and the halogen heater 162 of the cleaning roller 103 are used, the temperature of the contact portion between the fixing belt 121 and the cleaning roller 103, the cleaning roller 103, and the like. The temperature at the contact portion with the cleaning web 104 is adjusted to be higher than the melting point of the wax. Thus, when the positions of the cleaning roller 103 and the support heating roller 123 are separated from each other, the cleaning roller 103 is further provided with a halogen heater 162 as a heat source to heat the cleaning roller 103, respectively. The temperature of the contact portion can be easily adjusted. The same effect could be obtained by making the roughness relationship among the cleaning roller, the cleaning web, and the wax uniformizing member the same magnitude relationship as in the embodiment shown in FIG.

  As another example, as shown in FIG. 4, when the cleaning roller 103 is in contact with the support heating roller 123 via the fixing belt 121A, the halogen of the support heating roller 123 is used. Even with the heater 161 alone, the temperature at the contact portion between the fixing belt 121 and the cleaning roller 103 and the temperature at the contact portion between the cleaning roller 103 and the cleaning web 104 can be easily adjusted to be higher than the melting point of the wax. Therefore, it is not necessary to provide the halogen heater 162 on the cleaning roller 103. And the same effect could be acquired by making the roughness relationship between the cleaning roller, the cleaning web, and the wax uniformizing member the same magnitude relationship as the embodiment shown in FIGS.

1 is a schematic diagram illustrating a configuration of an image forming apparatus of the present invention. 1 is a schematic cross-sectional view for explaining an example of a fixing device of the present invention. 1 is a schematic cross-sectional view for explaining an example of a fixing device of the present invention. 1 is a schematic cross-sectional view for explaining an example of a fixing device of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 9Y, 9M, 9C, 9K Image forming unit 6 Intermediate transfer body 10 Fixing device 20 Paper feed cassette 101 Heat fixing roller 102 Pressure roller 103 Cleaning roller 104 Cleaning web 121 Wax equalizing member 121A Fixing belt 122 Top addition Pressure roller 123 Support heating roller 124 Lower pressure roller 161, 162 Halogen heater P Transfer material

Claims (6)

A fixing device that heat-fixes a transfer material on which an unfixed image formed using a toner containing wax is transferred to a fixing nip portion provided between a heated fixing rotator and a pressure member. There,
A cleaning unit for cleaning dirt on the surface of the fixing rotator is provided on the upstream side in the rotation direction of the fixing rotator to be thermally fixed in contact with the toner image on the transfer material, and on the downstream side of the fixing nip portion. Provided on the upstream side is a wax uniformizing member in contact with the fixing rotator,
The cleaning unit includes a cleaning rotator that contacts the fixing rotator, and a cleaning member that contacts the cleaning rotator.
The fixing device according to claim 1, wherein a surface roughness Rz of the wax uniformizing member is made smaller than a larger surface roughness Rz of the cleaning rotator and the cleaning member. The fixing device according to claim 1, wherein the wax uniformizing member is a rotating roller. The fixing device according to claim 1, wherein the wax uniformizing member is a rotating roller having a built-in heater. The fixing device according to claim 1, wherein the wax uniformizing member is a plate-like blade having elasticity. The larger surface roughness Rz of the cleaning rotating body and the cleaning member is 4.0 μm or less, and the surface roughness Rz of the wax uniformizing member is 1.6 μm or less. Item 5. The fixing device according to any one of Items 1 to 4. An image forming apparatus comprising the fixing device according to claim 1.

Images