Image forming apparatus

Abstract

To provide an image forming device capable of excellently maintaining the carrying performance of a recording medium over a long period of time.SOLUTION: An image forming apparatus comprising a support, an elastic member in close contact with the support, an endless belt, and a nip portion, wherein the nip portion is formed by the elastic member and the endless belt, the support in close contact with the elastic member pressed by the nip portion is a support made of an aluminum alloy containing silicon, and a silicon content in the aluminum alloy is in a range of 0.8 to 12.0% by mass.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus that can maintain good transportability of a recording medium for a long period of time. [Background technology]

[0002] There are various processes that are performed during image formation. For example, in a transport process in which a recording medium is transported in a fixed position, a function that maintains excellent transportability is required. In this process, a nip is generally formed between a pressing member and a pressed member by providing an elastically deformable member on the surface of a support that receives a pressing force, and the recording medium is then transported in a fixed position by passing through the nip. Then, the recording medium is transported by a roller or transport belt, for example, having a silicone rubber member provided on the surface of a support made of aluminum or iron.

[0003] In addition to the transport process in which a recording medium is fixed and transported, various processes are carried out during image formation, such as a transfer process in which toner is transferred to the recording medium, and a fixing process in which toner on the recording medium is fixed by efficiently applying heat and pressure, etc. In these processes, various improvements in functions are required in addition to the function of maintaining excellent transportability, and various technologies have been disclosed.

[0004] For example, Patent Document 1 discloses a technology for improving the fixing property of toner in the fixing process by using a manganese-based aluminum alloy as the core material of the fixing roller to improve the strength of the aluminum alloy and by thinning the core material to increase the heat transfer coefficient.

[0005] Patent Document 2 discloses a technology for achieving both low-temperature fixability and paper separation in the fixing process by improving the toner structure.

[0006] However, in recent years, from the viewpoint of increasing image formation speed and saving energy, there has been a growing demand for more advanced processes such as transfer processes and fixing processes. Also, in order to accommodate various recording media such as thin paper and textured paper, there has been a growing demand for a function that maintains transportability in the transport process. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-282023 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-186640 Summary of the Invention [Problem to be solved by the invention]

[0008] If the intention is to perform long-term printing so as to achieve both improved toner fixation and improved recording medium transportability, there is no problem in the early stages of printing, but in the later stages of printing, it becomes difficult to achieve both, and there is a problem that the recording medium transportability cannot be maintained.

[0009] The above problem is thought to be caused by the deterioration of various components in the image forming device as the number of prints increases, which in turn causes changes in the pressure distribution on the recording medium during printing. This problem is particularly likely to occur when the recording medium is thin paper.

[0010] The technology disclosed in the aforementioned Patent Document 1 can improve the fixability of toner, but has the problem that it cannot respond to changes in pressure distribution on the recording medium during the later stages of printing in long-term printing, and therefore cannot maintain the transportability of the recording medium during the transport process.

[0011] The technology disclosed in the aforementioned Patent Document 2 can achieve both low-temperature fixability and paper separation in the fixing process, but in the later stages of printing during long-term printing, it was not possible to maintain the transportability of the recording medium, as in Patent Document 1.

[0012] For these reasons, it has been difficult for conventional technology to meet today's high demands on fixing processes, transport processes, etc., even during long-term printing, and further improvements in functionality have been desired for image forming apparatuses.

[0013] The present invention has been made in view of the above problems and circumstances, and the problem to be solved is to provide an image forming apparatus that can maintain good transportability of a recording medium for a long period of time. [Means for solving the problem]

[0014] In order to solve the above-mentioned problems, the inventors have investigated the causes of the above-mentioned problems and have found that the above-mentioned problems can be solved by using a support made of an aluminum alloy containing silicon as a support that is in close contact with an elastic member that is affected by the pressing force from the nip formed by the components of the image forming apparatus, and by setting the silicon content in the aluminum alloy to a range of 0.8 to 12.0 mass %, thereby arriving at the present invention. That is, the above-mentioned problems of the present invention are solved by the following means.

[0015] 1. An image forming apparatus comprising a support, an elastic member that is in close contact with the support, an endless belt, and a nip portion, the nip portion is formed by the elastic member and the endless belt, a support body that is in close contact with the elastic member that is pressed in the nip portion is made of an aluminum alloy containing silicon, and The silicon content in the aluminum alloy is within the range of 0.8 to 12.0 mass%. An image forming apparatus characterized by:

[0016] 2. The endless belt is a belt for transporting a recording medium, and At least one of the nip portions is formed by the elastic member and a belt that transports the recording medium. 2. The image forming apparatus according to claim 1,

[0017] 3. The copper content in the aluminum alloy is 1.1% by mass or less. 2. The image forming apparatus according to claim 1,

[0018] 4. The nip portion is formed by the endless belt and two rotating bodies that face each other with the endless belt sandwiched therebetween. 2. The image forming apparatus according to claim 1,

[0019] 5. A support member is provided on the inside of the endless belt, and is in close contact with the elastic member pressed at the nip portion. A pressure rotating body is provided on the outer side of the endless belt to press the elastic member at the nip portion. 2. The image forming apparatus according to claim 1,

[0020] 6. Equipped with a transfer means; The nip portion is formed by a member that constitutes the transfer means. 2. The image forming apparatus according to claim 1,

[0021] 7. Equipped with fixing means; The nip portion is formed by a member that constitutes a fixing means. 2. The image forming apparatus according to claim 1,

[0022] 8. The fixing means includes a heating member. 8. The image forming apparatus according to claim 7, [Effects of the Invention]

[0023] According to the above-described means of the present invention, it is possible to provide an image forming apparatus capable of maintaining good transportability of a recording medium for a long period of time. The mechanism by which the effects of the present invention are manifested or the mechanism of action is not clear, but is speculated as follows.

[0024] In the image forming apparatus of the present invention, the support member that is in close contact with the elastic member that is affected by the pressing force from the nip formed by the components is made of an aluminum alloy containing silicon, and the silicon content in the aluminum alloy is set to be within the range of 0.8 to 12.0 mass %.

[0025] During long-term printing, the more times printing is performed, the more deterioration of the components of the image forming device progresses. Among these components, there are components that affect the transportability of the recording medium, and these components are generally composed of a support, an elastic member that is in close contact with the support, and an endless belt.

[0026] The nip portion of the present invention is formed by the elastic member and the endless belt, and during printing, the pressure applied from the nip portion to the elastic member is maintained in an appropriate distribution state, thereby maintaining good adhesion between the support and the elastic member for a long period of time.

[0027] The above-described excellent adhesion over a long period of time can be maintained by ensuring that the surface of the support that comes into contact with the elastic member, i.e., the surface roughness of the support, is appropriate. The surface roughness of the support can be maintained appropriately over a long period of time by using an aluminum alloy support containing silicon, and by setting the silicon content in the aluminum alloy within the range of 0.8 to 12.0 mass%.

[0028] By maintaining the surface roughness of the support over a long period of time, misalignment between the support and the elastic member is less likely to occur over a long period of time. This makes it possible to stably maintain the pressure applied to the endless belt that contacts the elastic member. In other words, it is possible to maintain an appropriate pressure distribution in the nip portion even during long-term printing, which is thought to enable good transportability of the recording medium to be maintained over a long period of time. [Brief explanation of the drawings]

[0029] [Figure 1] Diagram to explain the state of silicon as a function of temperature [Figure 2] Eutectic state image of aluminum alloy with 7 mass% silicon content [Figure 3] Eutectic state image of aluminum alloy with 12.6 mass% silicon content [Figure 4] Eutectic state image of aluminum alloy with 18 mass% silicon content [Figure 5] An example of a schematic cross-sectional view showing the overall configuration of an image forming apparatus [Figure 6] An example of a schematic cross-sectional view showing the configuration of the fixing unit [Figure 7] An example of a block diagram showing the configuration of the control unit [Figure 8] An example of a schematic cross-sectional view showing the configuration of the fixing unit DETAILED DESCRIPTION OF THE INVENTION

[0030] The image forming apparatus of the present invention is an image forming apparatus comprising a support, an elastic member in close contact with the support, an endless belt, and a nip portion, wherein the nip portion is formed by the elastic member and the endless belt, and the support in close contact with the elastic member pressed at the nip portion is made of an aluminum alloy containing silicon, and the silicon content in the aluminum alloy is within the range of 0.8 to 12.0 mass%. This feature is a technical feature common to or corresponding to each of the following embodiments (modes).

[0031] As an embodiment of the present invention, it is preferable from the viewpoint of improving the transportability of the recording medium that the endless belt is a belt that transports a recording medium, and that at least one of the nip portions is formed by the elastic member and the belt that transports the recording medium.

[0032] It is preferable that the copper content in the aluminum alloy is 1.1 mass % or less, from the viewpoint of improving the workability of the support and also improving the adhesion between the support and the elastic member.

[0033] It is preferable from the viewpoint of improving the transportability of the recording medium that the nip portion is formed by the endless belt and two rotating bodies that face each other with the endless belt sandwiched therebetween.

[0034] From the viewpoint of improving the transportability of the recording medium, it is preferable to provide a support on the inside of the endless belt that is in close contact with the elastic member that is pressed at the nip portion, and to provide a pressure rotating body on the outside of the endless belt that presses the elastic member at the nip portion.

[0035] The present invention can also be suitably applied to a case where a transfer means is provided and the nip portion is formed by a member that constitutes the transfer means.

[0036] The present invention can also be suitably applied to a case where a fixing means is provided and the nip portion is formed by a member that constitutes the fixing means.

[0037] The present invention can also be suitably applied to a case where the fixing means includes a heating member.

[0038] The present invention, its components, and embodiments for carrying out the present invention will be described in detail below. In this application, the symbol "to" is used to mean that the numerical values ​​before and after it are included as lower and upper limits.

[0039] However, advantages and features provided by one or more embodiments of the present invention will be more fully understood from the following detailed description and the accompanying drawings, which are for illustrative purposes only and are not intended to define the limits of the invention.

[0040] [Image forming equipment] 1. Overview The image forming apparatus of the present invention is an image forming apparatus comprising a support, an elastic member in close contact with the support, an endless belt, and a nip portion, wherein the nip portion is formed by the elastic member and the endless belt, and the support in close contact with the elastic member pressed at the nip portion is made of an aluminum alloy containing silicon, and the silicon content in the aluminum alloy is within the range of 0.8 to 12.0 mass%.

[0041] The effects of the present invention are particularly pronounced in fixing members that are susceptible to deterioration due to heat, but are not limited to this.Furthermore, the present invention is not limited to image forming apparatuses that use electrophotographic processes, but can also be applied to image forming apparatuses that apply heat to printed images to perform lamination processing.

[0042] (Definition of the nip) The "nip portion" according to the present invention refers to a contact portion between a pressing member and a pressed member among the constituent members of the image forming apparatus.

[0043] For example, when an endless belt is used as the pressing member and an elastic member that is in close contact with the support is used as the pressed member, the contact portion between the endless belt and the elastic member is the nip portion.

[0044] When an endless belt is sandwiched between members A and B, member A is a fixing roller, and member B is a member composed of a support and an elastic member that is in close contact with the support, the endless belt can be regarded as the pressing member and the elastic member as the pressed member. In this case, the contact area between the endless belt and the elastic member is the nip portion.

[0045] When member A and member B sandwich an endless belt, member A is a fixing roller, and member B is a member composed of a support and an elastic member that is in close contact with the support, the endless belt can be considered the pressed member and the fixing roller can be considered the pressing member. In this case, the contact area between the endless belt and the fixing roller is the nip portion.

[0046] Alternatively, it can be considered that member A presses member B with the endless belt sandwiched between them. In this case, the pressing member is member A, which is the fixing roller, and the pressed member is member B, which is made up of a support and an elastic member that is in close contact with the support. In this case, the contact area between the endless belt and the fixing roller and the contact area between the elastic member and the endless belt are collectively referred to as the "nip area."

[0047] Therefore, in this specification, the term "nip portion" includes the meaning of "the contact portion between the endless belt and the elastic member" as well as "the contact portion between the endless belt and the fixing roller."

[0048] The image forming apparatus of the present invention includes a nip portion formed by a pressing member and a pressed member, an elastic member that is affected by the pressing force from the nip portion, and a support that is in close contact with the elastic member.

[0049] The adhesion of the support to the elastic member varies depending on the surface roughness of the support, and when the support is made of an aluminum alloy, good adhesion can be maintained by ensuring that the silicon content in the aluminum alloy is within an appropriate range, specifically, 0.8 to 12.0 mass%.

[0050] (1.1) Elements in aluminum alloys If the silicon content in the aluminum alloy exceeds 0.6% by mass, a sea-island structure is formed in which silicon crystallites (eutectic) are dispersed in the aluminum phase, and appropriate irregularities are formed on the outer surface of the support. However, if the silicon content in the aluminum alloy is less than 0.8% by mass, crystal growth is insufficient, and the outer surface of the support does not have appropriate surface roughness, resulting in insufficient adhesion.

[0051] Furthermore, if the silicon content in the aluminum alloy is 12.6 mass% or less, coarse crystals (protrusions) due to the eutectic crystal of silicon and aluminum are unlikely to occur. However, if the silicon content in the aluminum alloy exceeds 12.0 mass%, the outer peripheral surface of the support does not have an appropriate surface roughness, resulting in insufficient adhesion.

[0052] For these reasons, in order to improve the adhesion between the support and the elastic member that adheres to the support and to achieve the effects of the present invention, the silicon content in the aluminum alloy is in the range of 0.8 to 12.0 mass %. Furthermore, from the viewpoint of improving adhesion, the silicon content in the aluminum alloy is preferably in the range of 5.0 to 10.0 mass %.

[0053] (metallic element) The aluminum alloy contains metal elements such as copper, iron, manganese, and magnesium in addition to silicon to ensure strength.

[0054] The inclusion of copper in the aluminum alloy is preferable from the viewpoint of improving the workability of the support and preventing defects, but if the copper content is too high, the formation of Si-Al eutectic is inhibited, and the surface roughness of the support becomes inappropriate, making it difficult to obtain the effects of the present invention.

[0055] Therefore, it is preferable that the copper content in the aluminum alloy is 1.1 mass % or less, from the viewpoint of improving the workability of the support and also improving the adhesion between the support and the elastic member.

[0056] Furthermore, if the content of metal elements other than copper, i.e., metal elements such as iron, manganese, and magnesium, is too high and the strength is increased too much, it will affect the workability of the support and the runout accuracy required of the support. Therefore, it is preferable that the content of metal elements such as iron, manganese, and magnesium is 5.0 mass% or less. Note that "runout accuracy" means the total runout tolerance in the axial or circumferential direction as defined in JIS B0021.

[0057] (state of silicon) Figure 1 is a diagram illustrating the state of silicon as a function of temperature. For example, as shown in Figure 1, an aluminum alloy containing silicon is a eutectic system with a eutectic point at 577°C, where the silicon content is 12.6 mass%, and when the alloy is cooled in a liquid state (L), it undergoes eutectic solidification. Hereinafter, "aluminum alloy containing silicon" will also be simply referred to as "Si-Al alloy."

[0058] Figures 2, 3, and 4 are some images of the eutectic state of the microstructure of a powder sample of aluminum alloy containing silicon. Figure 2 shows an image of the eutectic state of a silicon content of 7 mass%, Figure 3 shows an image of a silicon content of 12.6 mass%, and Figure 4 shows an image of a silicon content of 18 mass%.

[0059] Silicon crystals that crystallize in the eutectic state hardly dissolve aluminum, and grow as thin, narrow plate-like crystals as shown in Figure 3. On the other hand, when the silicon content increases and a hypereutectic state is reached, anisotropic coarse crystals are formed as shown in Figure 4.

[0060] The surface of a Si-Al alloy in the eutectic composition region has a sea-island structure as shown in Figure 2 or Figure 3, and gives the surface roughness depending on the silicon content (see Kitaokayama Osamu et al., Light Metals, Vol. 38, (7), 426, (1988)).

[0061] In the present invention, the silicon content of the aluminum alloy support is within the range of 0.8 to 12.0 mass %, so that minute irregularities are generated on the surface of the support, resulting in an appropriate surface roughness, thereby improving the adhesion between the support and the elastic member that is in close contact with the support.

[0062] Therefore, even when printing is performed over a long period of time, it is possible to stably maintain the pressure distribution on the elastic member at the nip portion formed by the above-mentioned elastic member and the belt in the image forming device, and the transportability of the recording medium is maintained well over a long period of time.

[0063] (Method for measuring elemental amounts) The element contents in the aluminum alloy support according to the present invention can be measured by a known elemental analysis method using metal spectroscopic analysis of the support. Specifically, the element contents are measured by qualitative and quantitative analysis using an X-ray fluorescence analyzer "XRF-1700" (manufactured by Shimadzu Corporation) under the following measurement conditions. <Measurement conditions> Slit: Standard Attenuator: None ·Spectroscopic crystal (Cu=LiF, Si=PET) Detector (Cu=SC, Si=FPC)

[0064] (1.2) Method for adjusting aluminum alloy composition Aluminum alloys are sometimes refined from bauxite, but are often produced from aluminum alloy scrap in order to conserve resources, reduce carbon dioxide emissions, and save energy.

[0065] However, since aluminum alloy scrap inevitably contains non-aluminum elements, it is necessary to adjust the composition of the aluminum alloy.

[0066] Furthermore, metal elements other than aluminum are added to aluminum alloys, regardless of whether they are recycled or not, in order to control their physical properties and workability.

[0067] In particular, silicon is added to various types of aluminum alloys because it affects heat resistance, thermal expansion, processability, etc. Such silicon-containing aluminum alloys are used in components of electrophotographic image forming devices.

[0068] The aluminum raw material used for each component of the image-forming apparatus of the present invention may be scrap of an aluminum alloy whose components are known. Metallic silicon or the like may also be added to adjust the components.

[0069] The composition of the aluminum alloy can be adjusted by melting two or more aluminum raw materials. In the following description, it is assumed that two aluminum raw materials, a first raw material and a second raw material, are used, and the composition of the aluminum alloy is adjusted by mixing the second raw material with the first raw material.

[0070] The silicon content in the aluminum alloy according to the present invention is within the range of 0.8 to 12.0% by mass. Therefore, for example, when the silicon content of the first raw material exceeds 12.0% by mass, the silicon content of the second raw material may be adjusted to be less than that of the first raw material to dilute the silicon in the aluminum alloy.

[0071] Conversely, if the silicon content of the first raw material is less than 0.8 mass%, the silicon content of the second raw material may be adjusted to be greater than that of the first raw material so as to concentrate silicon in the aluminum alloy.

[0072] When producing an aluminum alloy, if the amount of an element contained in the first raw material is not within the desired range, it is possible to adjust the composition of the aluminum alloy that is finally produced by diluting or concentrating it with the second raw material, in the same way as when adjusting the silicon content as described above.

[0073] Furthermore, as the aluminum raw material, a melted aluminum alloy with a defined standard may be used.

[0074] Examples of the aluminum alloy include JIS 2000 series aluminum, JIS 3000 series aluminum, JIS 4000 series aluminum, JIS 5000 series aluminum, JIS 6000 series aluminum, and JIS 7000 series aluminum.

[0075] (1.3) Method for processing aluminum alloy into a support shape The wrought aluminum alloy material can be processed into the shape of the support by any of the existing methods such as rolling, extrusion, casting, etc. Alternatively, two or more of these methods may be combined.

[0076] 2. Overall configuration of image forming device FIG. 5 is a schematic cross-sectional view showing an example of the overall configuration of an image forming apparatus.

[0077] The image forming apparatus 1 includes an image forming unit 10, a feeding unit 11, a fixing unit 12, an operation unit 13, and a control unit 14. It also includes a secondary transfer roller 18.

[0078] (2.1) Image forming section The image forming section 10 includes image forming units 15Y, 15M, 15C, and 15K, an intermediate transfer belt 16, and a primary transfer roller 17.

[0079] (Image forming unit) The image forming units correspond to the colors Y (yellow), M (magenta), C (cyan), and K (black). The image forming units 15K, 15Y, 15M, and 15C all have the same configuration, and for each image forming unit, a toner image of the corresponding color (K, Y, M, or C) is formed on a photosensitive member.

[0080] The operation of each of the image forming units 15K, 15Y, 15M, and 15C is performed with a staggered timing so that the toner images are primarily transferred onto the intermediate transfer belt 16 in a superimposed state at the same position on the intermediate transfer belt 16. As a result, color toner images of each color, Y (yellow), M (magenta), C (cyan), and K (black), are formed on the intermediate transfer belt 16.

[0081] As described above, the image forming units 15K, 15Y, 15M, and 15C all have the same configuration, so the image forming unit 15K corresponding to the color K (black) will be described below.

[0082] The image forming unit 15K includes a photoconductor 21, a charging section 22, an exposure section 23, a developing section 24, and a cleaner 25.

[0083] [Photoreceptor] A photoreceptor is an object that carries a latent or visible image on its surface in electrophotographic image formation methods. In image formation, the surface of the photoreceptor is first charged, creating a potential difference between it and the support surface. Next, an exposure device generates charges from the photosensitive layer, which cancel out the charges on the photoreceptor surface, forming an electrostatic latent image on the photoreceptor surface. Next, a development bias voltage is applied to the developer carrier, electrostatically attracting toner from the developer carrier to the latent image portion on the photoreceptor surface, and the toner image is developed onto the photoreceptor.

[0084] The photoreceptor 21 is preferably composed of a support made of an aluminum alloy containing silicon and an elastic member that is in close contact with the support. In this case, the silicon content in the aluminum alloy is preferably within a range of 0.8 to 12.0 mass %. This allows the pressure distribution received from the nip to be stably maintained, further enhancing the effects of the present invention.

[0085] The photoreceptor 21 is disposed so as to face the primary transfer roller 17 across the intermediate transfer belt 16. The photoreceptor 21 is pressed by the primary transfer roller across the intermediate transfer belt 16, and a nip is formed at the contact point between these members.

[0086] The photoconductor 21 is pressed by a developing roller provided in the developing unit 24, and a nip is formed at the contact portion between the photoconductor 21 and the developing roller.

[0087] The photoreceptor 21 is uniformly charged by the charging unit 22. The photoreceptor 21 is rotated by a drive source (not shown) and is exposed to laser light emitted by the exposure unit 23, thereby forming an electrostatic latent image on the surface of the photoreceptor 21.

[0088] [Charging part] The charging section 22 is arranged along the circumferential direction of the photoreceptor 21. The charging section 22 keeps the photoreceptor 21 in a uniformly charged state.

[0089] [Exposure section] The exposure unit 23 includes a light-emitting element such as a laser diode, a lens, and the like, and modulates the laser light in response to a drive signal from the control unit 14 to expose and scan the photoreceptor 21. When the photoreceptor 21 is exposed to the laser light in a state where it is uniformly charged by the charging unit 22, an electrostatic latent image is formed on the surface of the photoreceptor 21.

[0090] [Developing section] The developing unit supplies a developer to the surface of the photoreceptor to develop the electrostatic latent image formed on the surface of the photoreceptor, thereby forming a toner image. The developing unit may be equipped with a lubricant supplying means for supplying a lubricant to the developer, and it is preferable that the developer contains a lubricant from the viewpoint of improving wear resistance.

[0091] The developing unit includes a developer carrier. The rotation of the developer carrier transports the developer to the photoreceptor 21. Then, a thin layer of toner on the developer carrier comes into contact with the photoreceptor 21 and develops the electrostatic latent image on the photoreceptor 21.

[0092] The developer carrier is connected to a voltage application device, which applies a DC and / or AC bias voltage to the developer carrier. By controlling the voltage applied to the developer carrier, the developing bias can be adjusted to a desired value.

[0093] An electric field is formed in the development section where the developer carrier and the photoconductor 21 face each other due to the potential difference (development potential difference) between the developer carrier and the potential of the electrostatic latent image carried by the photoconductor 21. The toner in the developer transported by the rotation of the developer carrier moves due to the force exerted by the electric field and is attracted to the electrostatic latent image on the photoconductor 21. The electrostatic latent image carried by the photoconductor 21 is visualized, and a toner image corresponding to the shape of the electrostatic latent image is formed on the surface of the photoconductor 21.

[0094] The developer carrier is composed of, for example, a developing sleeve, a flange, a shaft, and a magnet roller. Note that the above-mentioned "developing sleeve" is a means having a function of carrying an appropriately charged developer and supplying the developer to a photosensitive member on which an electrostatic latent image is formed, and is, for example, a part of a developer carrier provided in a developing unit provided in an electrophotographic image forming apparatus.

[0095] However, a developer carrier having a "developing sleeve" as part of its configuration does not necessarily have to include a magnet portion such as a magnet roller as part of its configuration. Also, the shape of the developing sleeve is not a simple cylindrical shape as disclosed in JP-A-2003-91084, and does not include tube-like shapes with lotus-root-shaped holes in the cross section.

[0096] The silicon content in the aluminum alloy in the material constituting the developer carrier is preferably within the range of 0.8 to 12.0% by mass. The aluminum alloy constituting the developer carrier does not include the materials constituting the flange, shaft, and magnet roller.

[0097] 〔cleaner〕 The cleaner 25 removes residual toner from the surface of the photoreceptor 21 before the photoreceptor 21 is exposed to the laser light emitted by the exposure unit 23 .

[0098] (Intermediate transfer belt) The intermediate transfer belt 16 is one embodiment of an endless belt according to the present invention. The nip portion according to the present invention is formed by the intermediate transfer belt 16, and the primary transfer roller 17 and photoreceptor 21 that face each other with the intermediate transfer belt 16 sandwiched therebetween.

[0099] (Primary transfer roller) The primary transfer roller 17 is one aspect of the "transfer means" according to the present invention. The primary transfer roller 17 is disposed on the opposite side of the photoreceptor 21, in contact with the circulating intermediate transfer belt 16. The primary transfer roller 17 transfers the toner image formed on the photoreceptor 21 onto the intermediate transfer belt 16, which is an endless belt.

[0100] The image forming apparatus 1 employs an intermediate transfer system in which a K toner image formed on the photoreceptor 21 is transferred onto the intermediate transfer belt 16 by a primary transfer roller 17, and each toner image transferred onto the intermediate transfer belt 16 is then transferred onto a recording medium by a secondary transfer roller 18. The present invention is not limited to this intermediate transfer system, and a direct transfer system in which the toner image formed on the photoreceptor is directly transferred onto a recording medium may also be employed.

[0101] (2.2) Feeding section The feeding section 11 includes a paper feed cassette 3, a feed roller 4, a transport roller pair 5, and a timing roller pair 6.

[0102] The paper feed cassette 3 accommodates recording media.

[0103] The delivery roller 4 comes into contact with the uppermost recording medium S in the paper feed cassette 3 and delivers the recording medium S to the conveyor belt 7. The "conveyor belt 7" is one aspect of the "endless belt" according to the present invention.

[0104] The transport roller pair 5 transports the recording medium S fed by the feed roller 4 toward the timing roller pair 6 .

[0105] The timing roller pair 6 sends the recording medium S downstream at a timing instructed by the control unit 14 .

[0106] (2.3) Secondary transfer roller The secondary transfer roller 18 is one embodiment of the "transfer means" according to the present invention. The nip portion according to the present invention is formed by the intermediate transfer belt 16, the primary transfer roller 17, and a roller 18A that faces the primary transfer roller across the intermediate transfer belt.

[0107] The roller 18A is preferably made of a support and an elastic member made of an aluminum alloy containing silicon. In this case, the silicon content in the aluminum alloy is within the range of 0.8 to 12.0 mass %. This improves the adhesion between the support and the elastic member, allowing the recording medium to be transported smoothly for a long period of time.

[0108] The recording medium S is conveyed on the conveyor belt 7 from the timing roller pair 6 of the feeding unit 11, and passes through the secondary transfer position 18a in synchronization with the movement of the toner image on the circulating intermediate transfer belt 16.

[0109] Then, when the recording medium S passes through the secondary transfer position 18a, the toner image on the intermediate transfer belt 16 is secondarily transferred onto the recording medium S by the secondary transfer roller 18. After passing the secondary transfer position 18a, the recording medium S is sent to the fixing unit 12.

[0110] (2.4) Fixing section The fixing unit 12 is one embodiment of the "fixing means" according to the present invention. The recording medium S, which is transported in the direction of arrow D from the secondary transfer roller 18, passes through the fixing nip 30, and the toner image on the recording medium S is fixed to the recording medium S by applying heat and pressure. The fixing nip 30 is one embodiment of the nip portion according to the present invention.

[0111] The recording medium S that has passed through the fixing unit 12 is discharged to the outside of the apparatus by a pair of discharge rollers 8 and is stored in a paper discharge tray 9.

[0112] FIG. 6 is an example of a schematic cross-sectional view showing the configuration of the fixing unit 12. As shown in FIG.

[0113] 6, the X-axis direction represents the left-right direction when the image forming apparatus 1 is viewed from the front side. The Y-axis direction represents the up-down direction when the image forming apparatus 1 is viewed from the front side. The Z-axis direction is a direction perpendicular to both the X-axis and the Y-axis, and corresponds to the depth direction of the image forming apparatus 1. FIG. 6 is a cross-sectional view of the fixing unit 12 cut along an XY plane perpendicular to the Z-axis.

[0114] The fixing unit 12 is made up of members arranged on the outside of the fixing belt 31 and members arranged on the inside of the fixing belt 31 .

[0115] (2.4.1) Components placed outside the fixing belt The components arranged outside the fixing belt 31 include a pressure roller 39, a drive motor 40, and the endless fixing belt 31. Also arranged outside the fixing belt 31 is a non-contact temperature sensor 41.

[0116] (Pressure roller) The pressure roller 39 presses the pressure pad 32, which is disposed on the inner side of the fixing belt 31 with the fixing belt 31 sandwiched therebetween, from the outer circumferential surface 312 of the fixing belt.

[0117] The pressure roller 39 is driven to rotate at a predetermined speed in the direction of arrow A by the rotational driving force of the drive motor 40. The rotation of the pressure roller 39 causes the fixing belt 31 to rotate (run) in the direction of arrow B in response.

[0118] The pressure roller 39 is formed by laminating, in this order, an elastic layer 39b made of a heat-resistant material such as silicone rubber or fluororubber, and a release layer 39c provided with release properties such as a fluorine tube or fluorine-based coating on a solid shaft 39a made of aluminum, iron, or the like. The shaft 39a is not limited to being solid, and may be, for example, a metal pipe.

[0119] The pressure roller 39 has an axis 399 of a shaft 39a that is parallel to the Z axis. Both axial ends of the pressure roller 39 are supported by a fixed frame (not shown) that constitutes part of the housing of the fixing unit 12 so as to be rotatable and swingable in directions toward and away from the fixing belt 31 (far-far direction). Hereinafter, the above-mentioned "fixed frame" may also be simply referred to as "frame."

[0120] At the same time, the outer peripheral surface 391 of the pressure roller 39 is pressed against the fixing belt 31 by the biasing force of a spring (not shown).

[0121] The pressure P applied by the pressure roller 39 to the pressure pad 32 disposed inside the fixing belt can be switched by a pressure switching mechanism (not shown).

[0122] During image formation, the pressing force is set to full pressure, and during non-image formation when image formation is not being performed, such as during standby or when the bypass path heating mode described below is being executed, the pressing force is set to a pressure smaller than full pressure (light pressure).

[0123] The reason for switching the pressure to a light pressure when no image formation is occurring is to prevent deformation of the pressure roller 39. In other words, if the pressure roller 39 continues to be elastically deformed by a strong full pressure while stopped, there is a risk of plastic deformation occurring, in which the pressure roller 39 remains significantly deformed and does not return to its original circular cross-sectional shape. Therefore, by switching to a light pressure when no image formation is occurring, such plastic deformation can be prevented.

[0124] (Drive motor) The drive motor 40 is, for example, a brushless DC motor.

[0125] When the rotation speed of the pressure roller 39 drops below a predetermined speed, the control unit 14 increases the current supplied to the drive motor 40 slightly to prevent the rotation speed of the pressure roller 39 from dropping.

[0126] Conversely, when the rotation speed of the pressure roller 39 exceeds a predetermined speed, the current supplied to the drive motor 40 is slightly reduced to perform roller rotation control that suppresses an increase in the rotation speed of the pressure roller 39.

[0127] By controlling the roller rotation as described above, the rotation speed of the pressure roller 39 is maintained at a predetermined speed, and the running speed of the fixing belt 31, which rotates in response to the pressure roller 39, is also stably maintained at the same speed as the peripheral speed of the pressure roller 39.

[0128] A torque sensor 42 is provided to detect the torque of the drive motor 40. The torque sensor 42 is, for example, a sensor that measures the value of current supplied to the drive motor 40. The magnitude of the rotation load on the pressure roller 39 is determined from the detection result of the torque sensor 42.

[0129] (Temperature sensor) A non-contact temperature sensor 41 that detects the temperature of the fixing belt 31 is disposed outside the fixing belt 31 near the first position 31α. The temperature sensor 41 sends the detected temperature of the fixing belt 31 to the control unit 14.

[0130] During image formation, the control unit 14 performs temperature control by switching the heater 36 on and off based on the temperature detected by the temperature sensor 41 so that the temperature of the fixing belt 31 is maintained at a fixing temperature T1 suitable for fixing, for example, 160°C.

[0131] By this temperature control during image formation, when the recording medium S conveyed on the conveyor belt 7 passes through the fixing nip 30, the undetermined image on the recording medium S is heated, melted, and pressurized to be fixed onto the recording medium S. The temperature sensor 41 is not limited to a non-contact type, and a contact type that comes into contact with the outer circumferential surface 312 of the fixing belt can also be used.

[0132] (2.4.2) Fuser belt The fixing belt 31 is formed by laminating, in this order, an elastic layer made of a highly heat-resistant material and a release layer provided with releasability, such as a fluorine tube or fluorine coating, on a base layer made of polyimide, SUS (stainless steel), Ni (nickel) electroforming, etc. Examples of highly heat-resistant materials include silicone rubber and fluororubber.

[0133] (2.4.3) Components placed inside the fixing belt Inside the fixing belt 31, there are arranged a pressure pad 32, a guide member 33, a support member 34, a heating roller 35, a heater 36, a lubricant application member 37, a bypass path portion 38, and the like.

[0134] The fixing belt 31 is one embodiment of an endless belt according to the present invention, and is wound around a pressure pad 32 that contacts the inner surface 311 of the fixing belt, a heating roller 35, and a guide member 33 that contacts the inner surface 311 of the fixing belt and guides the fixing belt 31.

[0135] When the heating roller 35 is biased in a direction away from the pressure pad 32 by a member such as a spring (not shown), a certain amount of tension acts on the fixing belt 31.

[0136] (Pressure pad) The pressure pad 32 is one aspect of the elastic member according to the present invention. The pressure pad 32 is an elastic member disposed on the opposite side of the fixing belt 31 from the pressure roller 39, which is positioned outside the fixing belt 31, and receives the pressure from the pressure roller 39 via the fixing belt 31.

[0137] An outer peripheral surface 391 of the pressure roller 39 and an outer peripheral surface 312 of the fixing belt are pressed together to form a fixing nip 30 between the fixing belt 31 and the pressure roller 39. The fixing nip is one aspect of the nip portion according to the present invention. In the fixing nip 30, the pressure with which the pressure roller 39 presses the pressure pad 32 via the fixing belt 31 corresponds to the nip pressure.

[0138] The pressure pad 32 is made of a main body made of resin such as polyphenylene sulfide or metal, and has a sliding member (not shown) wound around it so as to surround the main body approximately once around.

[0139] The sliding member is a low-friction sheet, which may be, for example, a sheet having a glass cloth base and a sliding surface (outer surface) coated with a fluorine-based resin.

[0140] The sliding member may be made of any material that can reduce the sliding resistance with the fixing belt 31, and may be made of, for example, a fluororesin sheet, a glass coating, or a fluororesin fabric.

[0141] The pressure pad 32 may not be wound with a sliding member.

[0142] (Guide member) The guide member 33 is provided downstream of the pressure pad 32 in the belt running direction and upstream of the heating roller 35 in the belt running direction, and is disposed in close proximity to the pressure pad 32. The guide member 33 also guides the fixing belt 31 further downstream in the belt running direction immediately after it has passed through the fixing nip 30.

[0143] The pressure pad 32 and the guide member 33 are arranged side by side along the belt running direction inside the fixing belt 31, and are non-rotating bodies that do not rotate together with the fixing belt 31 as it rotates.

[0144] The pressure pad 32 and the guide member 33 may be made of the same material, such as a resin such as polyphenylene sulfide, polyimide, or liquid crystal polymer, and preferably a material with excellent heat resistance.

[0145] The pressure pad 32 and the guide member 33 may be made of metals such as aluminum and iron, ceramics, or a combination of these materials with silicone rubber, fluororubber, etc. The pressure pad 32 and the guide member 33 may be made of different materials.

[0146] (support member) The support member 34 is one embodiment of the support according to the present invention, and is a support that fixes and supports the pressure pad 32 and the guide member 33. The support member 34 is preferably a support made of an aluminum alloy containing silicon, and the silicon content in the aluminum alloy is preferably within the range of 0.8 to 12.0 mass %. This improves the adhesion between the pressure pad 32 and the support member 34, making it possible to maintain good transportability of the recording medium over a long period of time.

[0147] (heated roller) Heating roller 35 is configured by laminating an elastic layer made of elastic member 35b on cylindrical support 35a in this order. Heating roller 35 also includes heater 36 that applies heat to heating roller 35, thereby heating fixing belt 31. The center of the rotation axis of heating roller 35 is parallel to the Z-axis direction, and both axial ends of heating roller 35 are rotatably supported by a frame.

[0148] [Cylindrical support constituting the heating roller] The cylindrical support 35a is one embodiment of the support made of an aluminum alloy according to the present invention. The silicon content in the aluminum alloy is preferably within a range of 0.8 to 12.0 mass %. This improves the adhesion between the elastic member 35b and the support 35a, thereby maintaining good transportability of the recording medium for a long period of time.

[0149] [Elastic member constituting the heating roller] The elastic member 35b constituting the heating roller 35 is one aspect of the elastic member according to the present invention, and is preferably made of a highly heat-resistant material such as silicone rubber or fluororubber. The elastic member 35b is in close contact with the support 35a.

[0150] [Heater] The heater 36 is a long halogen heater that extends along the axial direction of the heating roller 35 and is inserted into the inner space of the cylindrical heating roller 35. The heater 36 applies heat generated by power supply from a power source (not shown) to the heating roller 35.

[0151] When the heater 36 is energized while the pressure roller 39 is rotating, the heat generated by the heater 36 is transferred from the heating roller 35 to the fixing belt 31, and reaches the fixing nip 30 as the fixing belt 31 rotates. As a result, the heat of the heater 36 is supplied to the fixing nip 30.

[0152] (lubricant application member) The lubricant application member 37 is made of a porous material such as a sponge or a fiber material such as aramid fiber or fluorine fiber impregnated with a lubricant. The lubricant application member 37 is fitted into a groove 339 provided in the guide member 33.

[0153] The upper surface of lubricant application member 37 contacts inner circumferential surface 311 of fixing belt 31, and this contact causes lubricant G to be applied to inner circumferential surface 311 of fixing belt 31. Application of lubricant G reduces the sliding resistance between fixing belt 31 and pressure pad 32 compared to a configuration in which lubricant G is not applied, and the rotation of fixing belt 31 becomes more stable.

[0154] Synthetic lubricating oil grease such as silicone grease or fluorine grease is used as the lubricant G. By using grease, which has a higher viscosity than oil, as the lubricant G, the lubricant G is less likely to leak out from both ends of the fixing belt 31 in the width direction.

[0155] The lubricant G used has the property that its viscosity decreases as the temperature increases. The lubricant G is not limited to grease, and other liquid materials may be used. Such other materials may include, for example, silicone-based or fluorine-based oil.

[0156] It is possible to adopt a configuration that does not include the lubricant application member 37. In this configuration, an appropriate amount of lubricant G is applied to the inner circumferential surface 311 of the fixing belt when the fixing unit 12 is manufactured or maintained.

[0157] (Bypass route section) The bypass path portion 38 is disposed in a space 313 that exists between the support member 34 and the heating roller 35 inside the fixing belt 31 .

[0158] The bypass path section 38 recovers the lubricant G applied to the inner surface 311 of the fixing belt at a first position 31α of one revolution of the fixing belt 31, and separates wear debris (not shown) from the lubricant G while allowing the recovered lubricant G to pass through.

[0159] The bypass path portion 38 then forms a bypass path that returns the separated lubricant G to the inner circumferential surface 311 of the fixing belt at a second position 31β that is forward in the belt running direction from the recovery position (first position).

[0160] The bypass path portion 38 includes a flat sponge body 380 made of an open-cell sponge as an example of a porous open-cell elastic member, and plate-like supports 381 and 382 that sandwich the sponge body 380 from both sides in the thickness direction.

[0161] The sponge body 380 forms a bypass path for the lubricant G, collects the lubricant G on the inner peripheral surface 311 of the fixing belt, and separates and filters the wear particles mixed in the lubricant G while causing the collected lubricant G to flow through the open bubbles.

[0162] An upper edge 385 of the sponge body 380 contacts the inner circumferential surface 311 of the fixing belt at a first position 31α in the belt running direction, and a lower edge 386 of the sponge body 380 contacts the inner circumferential surface 311 of the fixing belt at a second position 31β in the belt running direction.

[0163] Here, the first position 31α is a position on the fixing belt 31 that is downstream of the guide member 33 in the belt running direction and upstream of the heating roller 35 in the belt running direction.

[0164] The second position 31β is a position forward of the first position 31α in the belt running direction and lower than the first position 31α, in this case a position downstream of the heating roller 35 in the belt running direction and upstream of the pressure pad 32 in the belt running direction.

[0165] The sponge body 380 of the bypass path section 38 and the supports 381 and 382 sandwiching it are plate-like bodies that are long in the Z-axis direction.

[0166] Both longitudinal ends of supports 381 and 382 are fixedly supported by frames. In supports 381 and 382, ​​upper edge 385 of sponge body 380 contacts inner circumferential surface 311 of fixing belt at first position 31α.

[0167] In addition, the supports 381 and 382 support a main body portion (not shown) located between the upper edge portion 385 and the lower edge portion 386 of the sponge body 380 so that the lower edge portion 386 of the sponge body 380 is maintained in contact with the inner surface 311 of the fixing belt at the second position 31β.

[0168] Here, of both side surfaces of the main body (not shown), the portions that are in surface contact with the supports 381 and 382 are adhered to the supports 381 and 382 with an adhesive or the like. The supports 381 and 382 are not in contact with the inner circumferential surface 311 of the fixing belt.

[0169] The plate surface of sponge body 380 has a trapezoidal shape in a side view, and the length of an upper edge portion 385 of sponge body 380 in the belt width direction is substantially the same as the length of fixing belt 31 in the belt width direction. Therefore, at first position 31α, the entire upper edge portion 385 of sponge body 380 from one end to the other end in the belt width direction is in contact with inner circumferential surface 311 of the fixing belt.

[0170] On the other hand, the length of the lower edge 386 of the sponge body 380 in the belt width direction is shorter than the length of the upper edge 385 in the belt width direction and is also shorter than the length of the fixing belt 31 in the belt width direction.

[0171] Therefore, at the second position 31β, the following areas (1) and (2) of the inner circumferential surface 311 of the fixing belt are non-contact areas that are not in contact with the sponge body 380. (1) A region from one end of the lower edge 386 of the sponge body 380 in the belt width direction to one end of the fixing belt 31 in the belt width direction. (2) The region from the other end of the lower edge 386 of the sponge body 380 in the belt width direction to the other end of the fixing belt 31 in the belt width direction.

[0172] The reason for providing such a non-contact area is to prevent the lubricant G from leaking out of the fixing belt 31.

[0173] At the first position 31α, the lubricant G penetrates from the inner peripheral surface 311 of the fixing belt into the sponge body 380 through the upper edge 385 of the sponge body 380. The lubricant G present at one end on the front side of the device or the other end on the rear side in the belt width direction descends along the tapered side edge of the sponge body 380 on the front side of the device or the side edge on the rear side of the device, approaching the center in the belt width direction.

[0174] Then, at a second position 31β that is lower than the first position 31α, the lubricant G flows out of the sponge body 380 from a lower edge portion 386 of the sponge body 380 and is returned to the inner circumferential surface 311 of the fixing belt. When the lubricant G returned to the inner circumferential surface 311 of the fixing belt starts to flow toward the end side (outside) of the belt in the width direction, it is likely to leak out of the fixing belt 31 if there is no non-contact region.

[0175] However, if a non-contact region is provided, even if the lubricant G starts to flow outward in the belt width direction, the non-contact region allows the lubricant G to move on the inner circumferential surface 311 of the fixing belt up to one end or the other end in the belt width direction. Therefore, the amount of lubricant G leaking out of the fixing belt 31 can be reduced.

[0176] The lubricant G returned to the inner circumferential surface 311 of the fixing belt at the second position 31β reaches the pressure pad 32 as the fixing belt 31 rotates. Thereafter, the lubricant G passes through the gap between the pressure pad 32 and the inner circumferential surface 311 of the fixing belt toward the fixing nip 30, and is gradually spread to both ends in the belt width direction due to the contact pressure between the pressure pad 32 and the inner circumferential surface 311 of the fixing belt.

[0177] As a result, the lubricant G is distributed to both ends of the belt width direction in the fixing nip 30 where the pressing force is the highest, so that the sliding resistance between the pressing pad 32 and the inner surface 311 of the fixing belt does not increase at both ends of the belt width direction.

[0178] (2.5) Operation section The operation unit 13 is located on the front of the device in a position that is easy for the user to operate. The operation unit 13 is provided with keys and the like for receiving input of printing conditions such as the number of prints and density by the user.

[0179] (2.6) Control Unit The control unit 14 controls the operations of the image forming unit 10, the feeding unit 11, the fixing unit 12, the secondary transfer roller 18, etc., to perform a smooth image forming operation (printing).

[0180] FIG. 7 is an example of a block diagram showing the configuration of the control unit 14. As shown in FIG.

[0181] 7, the control unit 14 includes a CPU (Central Processing Unit) 141, a network I / F unit 142, a ROM (Read Only Memory) 143, and a RAM (Random Access Memory) 144. These can communicate with each other.

[0182] The CPU 141 can also communicate with the image forming unit 10, the feeding unit 11, the fixing unit 12, and the operation unit 13.

[0183] The network I / F unit 142 is configured by a communication control card such as a LAN card, and receives print job data sent from an external terminal device (not shown) via a network (such as a LAN).

[0184] The CPU 141 comprehensively controls the operations of the image forming unit 10 , the feeding unit 11 , and the fixing unit 12 , and smoothly executes a print job based on print job data received via the network I / F unit 142 .

[0185] The ROM 143 stores a control program for executing a print job and the like in advance. The CPU 141 operates in accordance with the control program stored in the ROM 143.

[0186] The RAM 144 provides a work area when the CPU 141 executes a program.

[0187] The CPU 141 includes a bypass path heating mode execution unit 145. The CPU 141 also controls the temperature of the fixing belt 31 based on the detection result of the temperature sensor 41.

[0188] Furthermore, the CPU 141 determines whether to execute the bypass path heating mode based on the detection result of the torque sensor 42. When it is determined to execute the bypass path heating mode, the bypass path heating mode execution unit 145 executes the bypass path heating mode.

[0189] The bypass path heating mode is an operation in which the temperature of the bypass path section 38 is heated at times other than during fixing until it rises to a temperature higher than that during fixing, thereby reducing the viscosity of the lubricant G, whose viscosity has increased due to the mixing of wear particles generated by the sliding friction between the pressure pad 32 and the inner surface 311 of the fixing belt.

[0190] Specifically, due to long-term sliding friction between pressure pad 32 and inner circumferential surface 311 of the fixing belt, one or both of inner circumferential surface 311 of the fixing belt and pressure pad 32 gradually wears away, and the amount of wear debris generated by this wear increases. The wear debris mixes with lubricant G on inner circumferential surface 311 of the fixing belt, and the viscosity of lubricant G increases as the amount of mixed-in wear debris increases.

[0191] As the viscosity of the lubricant G increases, the amount of lubricant G containing a large amount of wear debris that accumulates on the bypass path 38 increases, reducing the amount of lubricant G supplied between the pressure pad 32 and the inner circumferential surface 311 of the fixing belt. This increases the sliding resistance between the pressure pad 32 and the inner circumferential surface 311 of the fixing belt, which may eventually interfere with the stable running of the fixing belt 31.

[0192] On the other hand, the greater the sliding resistance between the pressure pad 32 and the inner circumferential surface 311 of the fixing belt, the greater the rotational load on the fixing belt 31. Also, the greater the rotational load on the fixing belt 31, the greater the rotational load on the pressure roller 39 that applies a force to the fixing belt 31 in the running direction.

[0193] From this, the rotational load of the pressure roller 39, i.e., the torque of the drive motor 40, can be said to be an index value that indicates the viscosity of the lubricant G due to the mixing of wear debris generated by the sliding friction between the pressure pad 32 and the inner surface 311 of the fixing belt.

[0194] Therefore, the load torque of the drive motor 40 is detected by the torque sensor 42, and if the detected current torque detection value Tr1 (corresponding to the viscosity of the lubricant G) exceeds the threshold value th1, the bypass path heating mode is executed.

[0195] Heating of the bypass path portion 38 is performed by the heater 36. Specifically, while the fixing belt 31 is rotating, the heater 36 is controlled to be switched on and off so that the temperature of the fixing belt 31 is maintained at a temperature T2 higher than the fixing temperature T1, for example, 200° C. Hereinafter, the fixing temperature T1 will be referred to as a first temperature T1, and the temperature T2 will be referred to as a second temperature T2.

[0196] During fixing, temperature control is performed to maintain the temperature of fixing belt 31 at first temperature T1, but in the bypass path heating mode, the temperature of fixing belt 31 rises to second temperature T2. Therefore, the temperature of sponge body 380 of bypass path portion 38 arranged inside fixing belt 31 also rises to a temperature higher than that during fixing.

[0197] As the temperature of the sponge body 380 rises from that during fixing, the viscosity of the lubricant G present at the contact portion between the upper edge portion 385 of the sponge body 380 and the inner surface 311 of the fixing belt and the lubricant G present inside the sponge body 380 decreases, the fluidity of the lubricant G increases, and the lubricant G becomes less likely to accumulate in the bypass path portion 38.

[0198] As a result, the lubricant G flows from the inner surface 311 of the fixing belt through the upper edge 385 of the sponge body 380, the main body 387 of the sponge body 380, and the bypass path 839 formed by continuous bubbles to the lower edge 386 of the sponge body 380 from top to bottom due to the effects of gravity and capillary action, and the wear particles mixed in the lubricant G are separated from the lubricant G within the sponge body 380 (filtered).

[0199] The lubricant G from which the wear debris has been separated flows out from the lower edge portion 386 of the sponge body 380 and is supplied to the inner circumferential surface 311 of the fixing belt.

[0200] Details of the processing of the print job and the processing of the bypass path heating mode can be the same as those in the embodiment described in paragraph 0125 and subsequent paragraphs of JP-A-2024-014253.

[0201] 3. Developer As the developer used for image formation, various known developers can be used, but it is preferable to use a two-component developer containing a toner and a carrier.

[0202] (3.1) Toner for developing electrostatic latent images (3.1.1) Toner base particles The toner base particles constituting the electrostatic latent image developing toner contained in the two-component developer contain, for example, a binder resin and, if necessary, a colorant. Hereinafter, the "electrostatic latent image developing toner" will also be simply referred to as "toner." Furthermore, the toner base particles may further contain other components such as a release agent and a charge control agent, if necessary.

[0203] In the present invention, the term "toner particles" refers to toner base particles to which an external additive has been added, and an aggregate of toner particles is called "toner."

[0204] Although toner base particles can generally be used as they are as toner particles, in the present invention, toner base particles to which external additives have been added are used as toner particles. In the following description, when there is no need to particularly distinguish between toner base particles and toner particles, they are also simply referred to as "toner particles." Hereinafter, each of the constituent materials of the toner base particles will be described in detail.

[0205] (binder resin) As the binder resin constituting the toner base particles, it is preferable to use a thermoplastic resin. As such a binder resin, any resin generally used as a binder resin constituting a toner can be used without any particular limitation.

[0206] (external additives) To control the fluidity and chargeability of the toner base particles, an external additive is attached to the surface of the toner base particles, and conventionally known metal oxide particles can be used as the external additive.

[0207] The metal oxide particles used as the external additive are preferably those whose surfaces have been subjected to hydrophobic treatment with a known surface treatment agent such as a coupling agent.

[0208] To further improve cleaning and transfer properties, a lubricant may be used as an external additive. Specific examples of the lubricant include salts of higher fatty acids such as zinc stearate and calcium stearate, and boron nitride.

[0209] The amount of these external additives added is preferably within a range of 0.1 to 10% by mass, more preferably within a range of 1 to 5% by mass, based on the total amount of the toner particles.

[0210] (mold release agent) The toner particles may contain a release agent. The release agent is not particularly limited. Examples of the release agent include hydrocarbon waxes such as polyethylene wax, oxidized polyethylene wax, polypropylene wax, oxidized polypropylene wax, and Fischer-Tropsch wax. Other examples include known release agents such as carnauba wax, fatty acid ester wax, sazol wax, rice wax, candelilla wax, jojoba oil wax, and beeswax. The content of the release agent in the toner particles is preferably within a range of 1 to 30 parts by mass, and more preferably within a range of 5 to 20 parts by mass, per 100 parts by mass of the binder resin.

[0211] (charge control agent) The toner particles may contain a charge control agent. Examples of the charge control agent include metal complexes of salicylic acid derivatives with zinc or aluminum (salicylic acid metal complexes). Other examples include calixarene compounds, organic boron compounds, and fluorine-containing quaternary ammonium salt compounds. The content of the charge control agent in the toner particles is preferably within a range of 0.1 to 5 parts by mass per 100 parts by mass of the binder resin.

[0212] (coloring agent) The toner particles may further contain a colorant to form a color toner. Usable colorants include known inorganic or organic colorants.

[0213] These colorants can be used alone or in combination as needed. When a colorant is used, the amount added is preferably within a range of 1 to 30% by mass, more preferably within a range of 2 to 20% by mass, based on the total mass of the toner.

[0214] The colorant may be surface-modified. Conventional surface modifiers may be used, and specific examples of the surface modifier include silane coupling agents, titanium coupling agents, and aluminum coupling agents.

[0215] (others) The volume average particle diameter of the toner particles is within the range of 3 to 10 μm. If the volume average particle diameter is less than 3 μm, the fluidity of the toner particles decreases, and the charge build-up of the toner particles decreases. On the other hand, if it exceeds 10 μm, the image quality decreases. The volume average particle diameter of the toner particles is preferably within the range of 3.5 to 6.5 μm. Specifically, the volume average particle diameter of the toner particles is the volume-based median diameter (D 50 ) shall be adopted.

[0216] The volume-based median diameter of toner particles (D 50) can be measured and calculated using a device that connects a computer system for data processing to a Multisizer 3 (manufactured by Beckman Coulter).

[0217] The measurement procedure involves mixing 0.02 g of toner particles with 20 mL of surfactant solution, followed by ultrasonic dispersion for 1 minute to prepare a toner particle dispersion. Note that the surfactant solution can be, for example, a surfactant solution prepared by diluting a neutral detergent containing surfactant components 10 times with pure water in order to disperse the toner particles.

[0218] This toner particle dispersion is pipetted into a beaker containing ISOTON II (manufactured by Beckman Coulter) in the sample stand until the measurement concentration is within the range of 5 to 10%.Then, the measurement is performed with the measuring instrument count set to 25,000 particles.The aperture diameter of the Multisizer 3 used is 100 μm.

[0219] The measurement range of 1 to 30 μm was divided into 256 parts, and the frequency count was calculated. The particle diameter of 50% of the particles with the largest volume fraction was determined as the volume-based median diameter (D 50 )

[0220] The volume average particle size of the toner particles is determined by the concentration of the coagulant and the addition of the organic solvent in the above-mentioned manufacturing method. It can be controlled by controlling the amount or the fusion time.

[0221] The average circularity of the toner particles is preferably 0.98 or less, and more preferably 0.930 to 0.975. If the average circularity is in this range, the toner particles will be more easily charged. The average circularity can be measured using, for example, a flow particle image analyzer "FPIA-3000" (manufactured by Sysmex Corporation), and specifically, it can be measured by the following method.

[0222] The toner particles are wetted in a surfactant solution and dispersed by ultrasonic dispersion for 1 minute. Then, using the "FPIA-3000," measurements are taken in HPF (high magnification imaging) mode at an appropriate concentration of 3,000 to 10,000 HPF detection particles. Within this range, reproducible measurements can be obtained. The circularity is calculated using the following formula (5).

[0223] Equation (5) Circularity = (perimeter of a circle with the same projected area as the particle image) / (perimeter of the particle projected image)

[0224] The average circularity is the arithmetic mean value obtained by adding up the circularity of each particle and dividing the sum by the total number of particles measured.

[0225] The average circularity of the toner particles can be controlled by controlling the temperature, time, etc. during the aging treatment in the above-mentioned production method.

[0226] (3.1.2) Toner manufacturing method Toner base particles, i.e., particles at a stage before adding external additives, can be produced by a known toner production method. Examples of such methods include a so-called pulverization method in which toner base particles are produced through kneading, pulverization, and classification processes, and a so-called polymerization method in which polymerizable monomers are polymerized and particles are formed while simultaneously controlling the shape and size. Toner particles are produced by adding and mixing external additives with toner base particles.

[0227] As a mixer for the external additives, various known mixers can be used, such as a Turbula mixer, a Henschel mixer, a Nauta mixer, a V-type mixer, etc. For example, when a Henschel mixer is used, the peripheral speed of the tip of the stirring blade is preferably set within a range of 30 to 80 m / s, and the mixture is stirred and mixed within a range of 20 to 50°C for about 10 to 30 minutes.

[0228] (3.2) Career One of the main roles of the carrier in two-component developers is to agitate and mix with the toner in the developer box and give the toner the desired charge. Another role of the carrier is to act as an electrode between the developer and the photoreceptor, transporting the charged toner to the electrostatic latent image on the photoreceptor and forming a toner image.

[0229] The carrier is held on the magnet roller by magnetic force, and after using it for development, it returns to the development box, where it is stirred and mixed with new toner again and is used repeatedly for a certain period of time. Therefore, in order to stably maintain the desired image characteristics, it is natural that the carrier characteristics must be stable throughout the period of use. "Image characteristics" include, for example, image density, fog, white spots, gradation, resolution, etc.

[0230] The carrier particles constituting the carrier are preferably formed by coating the surfaces of core particles, which are metal powders such as iron, ferrite, magnetite, etc., with a coating resin, as will be described later. The carrier particles may also contain internal additives such as a resistance adjuster, if necessary.

[0231] The surface of the core particle according to the present invention is preferably coated with a coating resin, and the coating resin preferably has a structure derived from (meth)acrylate. In this specification, (meth)acrylic means acrylic or methacrylic.

[0232] Examples of compounds having a structure derived from (meth)acrylate include methacrylic acid ester compounds, acrylic acid ester compounds, and alicyclic (meth)acrylic acid ester compounds. Alicyclic (meth)acrylic acid ester compounds are particularly preferred because they are highly hydrophobic and reduce the amount of water adsorbed by carrier particles in a high-temperature, high-humidity environment, thereby preventing a decrease in the charge amount.

[0233] The thickness of the resin coating layer is preferably in the range of 0.05 to 4 μm, and more preferably in the range of 0.2 to 3 μm. If the thickness of the resin coating layer is in this range, the chargeability and durability of the carrier particles can be improved.

[0234] The thickness of the resin coating layer can be determined by the following method.

[0235] Using a focused ion beam device "SMI2050" (manufactured by Hitachi High-Tech Science Corporation), carrier particles are cut along a plane passing through the center of the carrier particles to prepare a measurement sample. The cross section of the measurement sample is observed at a magnification of 5000 times using a transmission electron microscope "JEM-2010F" (manufactured by JEOL Ltd.), and the average value of the maximum and minimum thicknesses in that field of view is taken as the thickness of the resin coating layer. Five fields of view are measured.

[0236] The coating resin preferably contains at least one of carbon black, magnesium oxide, and titanium dioxide as a resistance adjuster from the viewpoint of adjusting the static resistance value of the carrier. Among these, carbon black is particularly preferred because of its ease of dispersion in the resin. [Example]

[0237] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these. In the examples, the terms "parts" and "%" are used, but unless otherwise specified, they represent "parts by mass" or "% by mass."

[0238] A. Preparation of the Support (A.1) Preparation of support [A1-0] A support [A1-0] was prepared by using ordinary aluminum, iron, and stainless steel as wrought materials and processing them into a shape similar to support 34 in Figure 6. The wrought materials used had a silicon content of at least less than 0.5 mass%. Hereinafter, "a shape similar to support 34 in Figure 6" will be referred to as a "U-shape" for convenience.

[0239] Whether the silicon content was less than 0.5% by mass was confirmed by qualitative and quantitative analysis using an X-ray fluorescence analyzer "XRF-1700" (manufactured by Shimadzu Corporation) under the following measurement conditions. <Measurement conditions> Slit: Standard Attenuator: None ·Spectroscopic crystal (Cu=LiF, Si=PET) Detector (Cu=SC, Si=FPC)

[0240] (A.2) Preparation of supports [A1-1] to [A1-11] Supports [A1-1] to [A1-11] were prepared by processing wrought silicon-containing aluminum alloys into a U-shape. The silicon and metal contents of each silicon-containing aluminum alloy were as shown in Table I. The metal element contents of each aluminum alloy were confirmed by qualitative and quantitative analysis using an X-ray fluorescence analyzer "XRF-1700" (manufactured by Shimadzu Corporation) under the above measurement conditions.

[0241] In Table I, the metal content of the wrought aluminum alloy used to fabricate the support [A1-0] was not specifically measured, and is therefore indicated as "-." "Si-Al wrought alloy" in Table I represents "aluminum alloy containing silicon."

[0242] (A.3) Preparation of support [A2-0] A support [A2-0] was prepared by processing a hollow cylindrical wrought material made of common aluminum, iron, or stainless steel. The wrought material used had a silicon content of at least less than 0.5% by mass.

[0243] (A.4) Preparation of supports [A2-1] to [A2-6] Supports [A2-1] to [A2-6] were prepared by processing a wrought material made of silicon-containing aluminum alloy into a hollow cylindrical shape. The metal content of each silicon-containing aluminum alloy was as shown in Table I.

[0244] In Table I, the metal content of the wrought aluminum alloy used to fabricate the support [A2-0] was not specifically measured, and is therefore indicated as "-." "Si-Al wrought alloy" in Table I represents "aluminum alloy containing silicon."

[0245] [Table 1]

[0246] B. Preparation of the Fixing Device Fixing device components were fabricated by forming an elastic layer so as to be in close contact with the support listed in Table I, and each fixing device was fabricated using these components. In the following description, the "position where support 34 is installed" in Figure 6 is referred to as "position α1," and the "position where support 35a is installed" is referred to as "position α2."

[0247] (B.1) Fabrication of fixing devices [1] to

[11] As fixing devices [1] to

[11] , fixing sections (fixing devices) having the configuration shown in FIG. 6 were fabricated.

[0248] (Production of fixing device [1]) An adhesive was applied to the surface of the U-shaped support [A1-1], and an LCO resin was molded into a shape that corresponded to the fixing device components as an elastic layer (elastic member).Then, the support [A1-1] was placed at position α1 relative to the fixing unit (fixing device) by closely adhering the elastic member and the support [A1-1], and the fixing unit (fixing device) was assembled with the support [A1-1].

[0249] In addition, silicone rubber was molded into a shape corresponding to the fixing device parts as an elastic layer (elastic member) on the surface of the support [A2-0] processed into a hollow cylindrical shape. Then, the support [A2-0] was placed at position α2 relative to the fixing section (fixing device) by closely adhering the elastic member to the support [A2-0] and incorporating it into the fixing section (fixing device).

[0250] In this way, a fixing device [1] was produced.

[0251] (Fabrication of Fixing Devices [2] to

[11] ) Fixing devices [2] to

[11] were produced in the same manner as fixing device [1], except that the support [A1-1] processed into a U-shape was changed as shown in Table II, and the support [A2-0] processed into a hollow cylindrical shape was changed as shown in Table II.

[0252] In Table II, the metal content of the wrought aluminum alloy used to fabricate the substrates [A1-0] and [A2-0] was not specifically measured, and is therefore indicated as "-." "Si-Al alloy wrought material" in Table I represents "aluminum alloy containing silicon."

[0253] (B.2) Fabrication of fixing devices

[12] to

[17] Fixing units (fixing devices) having the configuration shown in FIG. 6 were fabricated as fixing devices

[12] to

[17] .

[0254] (Production of fixing device

[12] ) An adhesive was applied to the surface of the U-shaped support [A1-0], and an LCO resin was molded into a shape that corresponded to the fixing device components as an elastic layer (elastic member).Then, the support [A1-0] was placed at position α1 relative to the fixing unit (fixing device) by closely adhering the elastic member to the support [A1-0] and incorporating it into the fixing unit (fixing device).

[0255] In addition, silicone rubber was molded into a shape corresponding to the fixing device parts as an elastic layer (elastic member) on the surface of the support [A2-1] processed into a hollow cylindrical shape. Then, the support [A2-1] was placed at position α2 relative to the fixing section (fixing device) by closely adhering the elastic member to the support [A2-1] and incorporating it into the fixing section (fixing device).

[0256] In this way, a fixing device

[12] was produced.

[0257] (Fabrication of fixing devices

[13] to

[17] ) Fixing devices

[13] to

[17] were fabricated in the same manner as fixing device

[12] , except that the support [A1-0] processed into a U-shape was changed as shown in Table II, and the support [A2-1] processed into a hollow cylindrical shape was changed as shown in Table II.

[0258] In Table II, the metal content of the wrought aluminum alloy used to fabricate the substrates [A1-0] and [A2-0] was not specifically measured, and is therefore indicated as "-." "Si-Al alloy wrought material" in Table II represents "aluminum alloy containing silicon."

[0259] [Table 2]

[0260] (B.3) Fabrication of fixing devices

[18] to

[28] Fixing units (fixing devices) having the configuration shown in Figure 8 were fabricated as fixing devices

[18] to

[28] . Figure 8 is an example of a schematic cross-sectional view showing the configuration of the fixing unit. Before describing the fabrication of the fixing devices, Figure 8 will be described below.

[0261] In FIG. 8, a fixing device 90 is composed of a heating roller 91 heated by a halogen heater H, a pressure roller 92 that presses the heating roller 91 from below, and the like.

[0262] The heating roller 91 is composed of a halogen heater H built in the center, a core metal 91A formed in a hollow cylindrical shape, a heat-resistant elastic layer 91B, and a release layer 91C that covers the elastic layer 91B with a tube.

[0263] In the following description, the elastic member does not refer only to the elastic layer 91B, but refers to the elastic layer 91B and the release layer 91C together.

[0264] The core metal 91A is made of an aluminum alloy, the elastic layer 91B is made of heat-resistant silicone rubber, and the release layer 91C is made of a fluororesin such as PFA (perfluoroalkoxy) or PTFE (polytetrafluoroethylene).

[0265] The pressure roller 92 is composed of a cylindrical core 92A made of stainless steel or the like, an elastic layer 92B made of silicone rubber foam and positioned on the outer surface of the core 92A, and a release layer 92C made of a PFA tube or the like and covering the outer surface of the elastic layer 92B.

[0266] The pressure roller 92 is biased by a biasing member (not shown) to press the heating roller 91 from below.

[0267] With the above configuration, when the heating roller 91, which is heated by the halogen heater H and driven by a motor (not shown), rotates clockwise, the pressure roller 92 rotates counterclockwise.

[0268] Therefore, the recording medium P on which a toner image is formed by the image forming device is sandwiched and transported in the nip portion N formed by the heating roller 91 and the pressure roller 92, and the toner image on the recording medium P is fixed by being heated and pressurized.

[0269] To prevent the toner image on the recording medium P from being pressed against the surface of the heating roller 91 and from wrapping around the heating roller 91 due to the stickiness of the softened toner, an air nozzle 101 that sprays compressed air is provided on the discharge side of the recording medium P relative to the nip N. This allows compressed air to be sprayed onto the heating roller 91, and the leading edge of the recording medium P that has wrapped around the heating roller 91 to be peeled off by the air pressure.

[0270] Furthermore, since the guide member 93 is provided so as to protrude from the air nozzle 101 toward the nip portion N, the peeled recording medium P is transported along the guide member 93 without coming into contact with the air nozzle 101 .

[0271] (Preparation of fixing device

[18] ) The support 91A portion of the fixing roller 91 became a support [B1-1] processed into a hollow cylindrical shape, and the elastic layer 91B portion on its surface was made of silicone rubber, and the fixing roller 91 was fabricated and incorporated into a fixing section (fixing device).

[0272] In this way, a fixing device

[18] was produced.

[0273] (Fabrication of fixing devices

[19] to

[28] ) Fixing devices

[19] to

[28] were produced in the same manner as the fixing device

[18] , except that the support [B1-1] processed into a hollow cylindrical shape was changed as shown in Table III.

[0274] In Table III, "Si-Al alloy" refers to an "aluminum alloy containing silicon."

[0275] [Table 3]

[0276] C. Preparation of Toner 1 (C.1) Preparation of amorphous polyester particle dispersion (a1) Into a reaction vessel equipped with a stirrer, a thermometer, a condenser, and a nitrogen gas inlet tube, the following monomer [1] and 0.25 parts by mass of "tin dioctylate" per 100 parts by mass of the total of the following monomer [1] were added.

[0277] <Monomer [1]> Bisphenol A ethylene oxide 2.2 mole adduct 40 mole parts Bisphenol A propylene oxide 2.2 mole adduct 60 mole parts Dimethyl terephthalate 60 parts by mole Dodecenyl succinic anhydride 20 mole parts

[0278] The reaction was carried out in a reaction vessel at 235°C for 6 hours under a nitrogen gas flow, after which the temperature inside the reaction vessel was lowered to 200°C, and 15 molar parts of dimethyl fumarate and 5 molar parts of trimellitic anhydride were added to the reaction vessel, followed by reaction in the reaction vessel for 1 hour.

[0279] The temperature in the reaction vessel was raised to 220°C over 5 hours, and polymerization was continued under a pressure of 10 kPa until the desired molecular weight was reached, producing a pale yellow, transparent amorphous polyester (A1). The amorphous polyester (A1) had a weight average molecular weight (Mw) of 35,000, a number average molecular weight (Mn) of 8,000, and a glass transition temperature (Tg) of 56°C.

[0280] Next, the amorphous polyester (A1) and the following mixed solution [2] were placed in the separable flask in the amounts shown below, and thoroughly mixed to dissolve.

[0281] Amorphous polyester (A1) 200.0 parts by mass

[0282] <Mixed solution [2]> Methyl ethyl ketone 100.0 parts by mass Isopropyl alcohol 35.0 parts by mass 10% by mass ammonia aqueous solution 7.0 parts by mass

[0283] Then, while the contents of the separable flask were heated and stirred at 40°C, ion-exchanged water was added dropwise at a rate of 8 g / min using a liquid-transfer pump. When the amount of ion-exchanged water reached 580 parts by mass, the addition of ion-exchanged water was stopped. The solvent was then removed under reduced pressure to prepare a dispersion liquid (a) of amorphous polyester particles.

[0284] Ion-exchanged water was added to the dispersion (a) to adjust the solid content to 25% by mass, thereby preparing an amorphous polyester particle dispersion (a1). The volume-based median diameter (d50) of the amorphous polyester particles contained in the dispersion (a1) was measured using a Microtrac UPA-150 (manufactured by Nikkiso Co., Ltd.) and found to be 156 nm.

[0285] (C.2) Preparation of amorphous vinyl resin particle dispersion (b1) A 5 L reaction vessel equipped with a stirrer, temperature sensor, condenser, and nitrogen inlet was charged with 5.0 parts by mass of an anionic surfactant (Dowfax, manufactured by The Dow Chemical Company) and 2,500 parts by mass of ion-exchanged water, and the temperature inside the reaction vessel was raised to 75°C while stirring at a speed of 230 rpm under a nitrogen stream. Next, a solution prepared by dissolving 18.0 parts by mass of potassium persulfate (KPS) in 342 parts by mass of ion-exchanged water was added to the reaction vessel, and the liquid temperature was raised to 75°C.

[0286] Further, a mixed solution consisting of the following monomer [3] was added dropwise to the reaction vessel in the amount shown below over a period of 2 hours.

[0287] <Monomer [3]> Styrene (St) 903.0 parts by mass n-Butyl acrylate (BA) 282.0 parts by mass Acrylic acid (AA) 12.0 parts by mass 1,10-decanediol diacrylate 3.0 parts by mass Dodecanethiol 8.1 parts by mass

[0288] After the dropwise addition was completed, polymerization was carried out by heating and stirring at 75°C for 2 hours to prepare a dispersion liquid (b) of amorphous vinyl resin particles. Ion-exchanged water was added to this dispersion liquid (b) to adjust the solid content to 25 mass% to prepare an amorphous vinyl resin particle dispersion liquid (b1). The "amorphous vinyl resin" contained in the above-mentioned amorphous vinyl resin particle dispersion liquid (b1) is referred to as "amorphous vinyl resin (B1)".

[0289] The volumetric ratio of the amorphous vinyl resin particles contained in the amorphous vinyl resin particle dispersion (b1) The median diameter (d50) was measured using Microtrac UPA-150 (manufactured by Nikkiso Co., Ltd.) and was found to be 160 nm.

[0290] The amorphous vinyl resin (B1) had a glass transition temperature (Tg) of 52°C, a weight average molecular weight (Mw) of 38,000, and a number average molecular weight (Mn) of 15,000.

[0291] (C.3) Preparation of crystalline polyester particle dispersion (c1) The following amount of monomer [4] was placed in a reaction vessel equipped with a stirrer, a thermometer, a condenser and a nitrogen gas inlet tube, and the atmosphere in the reaction vessel was replaced with dry nitrogen gas.

[0292] <Monomer [4]> Dodecanedioic acid 50 mole parts 1,6-Hexanediol 50 mole parts

[0293] Next, 0.25 parts by mass of titanium tetrabutoxide (Ti(On-Bu)4) was added to a total of 100 parts by mass of the monomer [4]. Under a nitrogen gas flow, the temperature inside the reaction vessel was raised to 170°C, and the mixture was stirred for 3 hours to carry out the reaction.

[0294] The temperature in the reaction vessel was then further increased to 210°C over 1 hour, the pressure in the reaction vessel was reduced to 3 kPa, and the mixture was stirred and reacted under reduced pressure for 13 hours. This yielded crystalline polyester (C1). The crystalline polyester (C1) had a weight average molecular weight (Mw) of 25,000, a number average molecular weight (Mn) of 8,500, and a melting point of 71.8°C.

[0295] Next, the crystalline polyester (C1) and a mixture of the following mixed solution [5] were placed in a separable flask in the amounts shown below, and after thorough mixing and dissolution at 60°C, 8 parts by mass of a 10% by mass aqueous ammonia solution was added dropwise.

[0296] Crystalline polyester (C1) 200 parts by mass

[0297] <Mixed solution [5]> Methyl ethyl ketone 120 parts by mass Isopropyl alcohol 30 parts by mass

[0298] Thereafter, the heating temperature was raised to 67°C, and ion-exchanged water was added dropwise at a rate of 8 g / min using a pump while stirring. When the amount of ion-exchanged water being fed reached 580 parts by mass, the addition of ion-exchanged water was stopped.

[0299] The solvent was then removed under reduced pressure to prepare a crystalline polyester particle dispersion (c). Ion-exchanged water was added to this dispersion (c) to adjust the solid content to 25% by mass, thereby preparing a crystalline polyester particle dispersion (c1). The volume-based median diameter (d50) of the crystalline polyester particles contained in the crystalline polyester particle dispersion (c1) was measured using a Microtrac UPA-150 (manufactured by Nikkiso Co., Ltd.) and found to be 198 nm.

[0300] (C.4) Preparation of release agent particle dispersion (W1) The release agent, surfactant, and ion-exchanged water shown below were mixed in the amounts shown below, and the release agent was dissolved in a pressure discharge homogenizer (Gaulin Homogenizer manufactured by Gaulin Co., Ltd.) at an internal liquid temperature of 120°C.

[0301] "FNP0090" (mold release agent) 270 parts by mass "Neogen RK" (surfactant) 13.5 parts by mass Ion-exchanged water 21.6 parts by mass

[0302] The release agent "FNP0090" (manufactured by Nippon Seiro) is a paraffin wax with a melting temperature of 89°C.

[0303] The surfactant "Neogen RK" (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) is an anionic surfactant.

[0304] The dispersion was then subjected to a dispersion treatment at a dispersion pressure of 5 MPa for 120 minutes, followed by 40 MPa for 360 minutes, and cooled to obtain dispersion (w). Further, ion-exchanged water was added to the dispersion (w) to adjust the solid content to 20%, and this was designated release agent particle dispersion (W1). The volume average particle diameter of the particles in release agent particle dispersion (W1) was 215 nm.

[0305] (C.5) Preparation of black colorant particle dispersion (1) The following resistance adjuster, surfactant, and ion-exchanged water were mixed in the amounts shown below, and pre-dispersed for 10 minutes using a homogenizer (ULTRA-TURRAX T50, manufactured by IKA).

[0306] "Regal (registered trademark) 330" (resistance adjuster) 100 parts by mass "Neogen SC" (surfactant) 15 parts by mass Ion-exchanged water 400 parts by mass

[0307] The "resistance adjuster" mentioned above is carbon black (manufactured by Cabot Corporation). The above "surfactant" is an anionic surfactant (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.).

[0308] Then, a high-pressure impact disperser, Ultimizer (manufactured by Sugino Machine), was used to perform a dispersion process at a pressure of 245 MPa for 30 minutes to obtain an aqueous dispersion of black colorant particles. Ion-exchanged water was further added to this aqueous dispersion of black colorant particles to adjust the solid content to 15% by mass, and this was designated black colorant particle dispersion (1). The volume-based median diameter (d50) of the colorant particles in black colorant particle dispersion (1) was measured using a Microtrac UPA-150 (manufactured by Nikkiso Co., Ltd.) and found to be 110 nm.

[0309] (C.6) Preparation of toner base particles (1) (Agglomeration / fusion process and aging process) The dispersion liquid prepared in (D.1) to (D.5) above, a surfactant, and ion-exchanged water were placed in the amounts shown below into a 4-liter reaction vessel equipped with a thermometer, a pH meter, and a stirrer, and 1.0% nitric acid was added at 25°C to adjust the pH to 3.0 to prepare a raw material dispersion liquid.

[0310] Amorphous polyester particle dispersion (a1) 1008 parts by mass Amorphous vinyl resin particle dispersion (b1) 32 parts by mass Crystalline polyester particle dispersion (c1) 160 parts by mass Release agent particle dispersion (W1) 160 parts by mass Black colorant particle dispersion (1) 187 parts by mass "Dowfax2A1" (surfactant) 40 parts by mass Ion-exchanged water 1500 parts by mass

[0311] The surfactant is an anionic surfactant.

[0312] Thereafter, while dispersing at 3000 rpm using a homogenizer "ULTRA-TURRAX T50" (manufactured by IKA), 100 parts by mass of a flocculant was added dropwise over 30 minutes. The flocculant used was an aqueous solution of aluminum sulfate with a concentration of 2%.

[0313] After the dropping of the coagulant was completed, the mixture was stirred for 10 minutes to thoroughly mix the raw material dispersion and the coagulant. After that, a stirrer and a mantle heater were installed in the reaction vessel.

[0314] The rotation speed of the stirrer was adjusted so that the slurry was stirred sufficiently, and the temperature inside the reaction vessel was increased at a rate of 0.2°C / min until the temperature reached 40°C.

[0315] After the temperature inside the reaction vessel exceeded 40°C, the temperature was increased at a rate of 0.05°C / min, and the particle size was measured every 10 minutes using a Coulter Multisizer 3 (aperture diameter 100 μm, manufactured by Beckman Coulter).

[0316] When the volume-based median diameter of the particles in the dispersion of the above raw materials reached 3.9 μm, the temperature was maintained, and a premixed mixture of the following amorphous polyester particle dispersion (a1) and a surfactant was added to the reaction vessel over 20 minutes.

[0317] <Mixed liquid> Amorphous polyester particle dispersion (a1) 400 parts by mass "Dowfax2A1" (surfactant) 15 parts by mass

[0318] The surfactant is an anionic surfactant.

[0319] Next, the reaction vessel was maintained at 50°C for 30 minutes, and then 8 parts by mass of a 20% EDTA (ethylenediaminetetraacetic acid) solution was added to the reaction vessel. A 1 mol / L aqueous sodium hydroxide solution was then added to the reaction vessel, and the pH of the raw material dispersion in the reaction vessel was controlled to 9.0. The temperature was then increased to 85°C at a rate of 1°C / min while adjusting the pH to 9.0 every 5°C, and the temperature was maintained at 85°C.

[0320] (cooling process) Thereafter, using "FPIA-3000," the dispersion was cooled at a temperature decreasing rate of 10°C / min when the shape factor reached 0.970, to prepare toner base particle dispersion (1).

[0321] (filtration, washing and drying processes) Thereafter, the toner base particle dispersion liquid (1) was filtered, thoroughly washed with ion-exchanged water, and then dried at 40° C. to prepare toner base particles (1). The volume-based median diameter of the prepared toner base particles (1) was 4.0 μm, and the average circularity was 0.971.

[0322] (C.7) Addition of external additives The following external additives were added in the amounts shown below to the toner base particles (1) prepared above, and mixed using a Henschel mixer (manufactured by Mitsui Miike Chemical Engineering Co., Ltd.).

[0323] <External additives> Hydrophobic silica (number average primary particle size 12 nm, hydrophobicity degree 68) 1.0 mass% Hydrophobic titanium oxide (number average primary particle size 20 nm, hydrophobicity degree 64) 1.5% by mass

[0324] Thereafter, coarse particles were removed using a sieve with 45 μm openings to prepare "Toner 1."

[0325] D. Preparation of carrier and developer (D.1) Preparation of coating resin Cyclohexyl methacrylate / styrene monomers were added in a mass ratio of (50:50) to an aqueous solution of 0.3 mass % sodium benzenesulfonate.

[0326] Potassium peroxodisulfate was added in an amount equivalent to 0.5% by mass of the total amount of the above monomers, and emulsion polymerization was carried out to produce coating resin 1. The weight average molecular weight of this coating resin 1 was measured using a known measuring device and was found to be 500,000.

[0327] (D.2) Preparation of Carrier 1 Carrier 1 was prepared according to the following procedure.

[0328] Volume average particle size is 35 μm, and saturation magnetization is 61 A m 2 / kg Mn-Mg-Sr ferrite particles were prepared. The volume resistivity of these ferrite particles was 4.5 × 10 7 It was Ωcm.

[0329] 100 parts by mass of the "core particles" prepared above and 3.5 parts by mass of "coating resin 1" were added to a high-speed mixer with a stirring blade. At this time, the mixture was mixed and stirred for 15 minutes at 22°C under the condition that the peripheral speed of the horizontal rotor was 8 m / sec. After that, the mixture was mixed for 50 minutes at 120°C to produce carrier 1 having a resin coating layer on the surface of the core particles by the action of mechanical impact force (mechanochemical method). The core exposed area ratio of carrier 1 was 10%, and the volume resistivity was 10 12 The resistance was Ω·cm.

[0330] (D.3) Preparation of developer Carrier 1 and Toner 1 were charged into a V-type mixer in the amounts shown below, and mixed for 5 minutes in an environment of normal temperature and humidity to prepare Developer 1.

[0331] Carrier 1 100 parts by mass Toner 1 6 parts by weight

[0332] E. Transportability evaluation (E.1) Examples 1 to 11 and Comparative Examples 1 to 6 The fixing device was appropriately modified and mounted in the combination of Table IV on an image forming apparatus "bizhub c360i" manufactured by Konica Minolta, Inc. Developer 1 was also loaded as the developer.

[0333] Long-term printing was carried out by printing 300,000 sheets on a recording medium at a printing rate of 5% coverage under conditions of a temperature of 23°C and 50% RH.

[0334] After long-term printing, <1> ~ <4> On the four types of recording media, printing was carried out on 10 sheets at a printing rate of 20% coverage. <Type of recording medium> <1> NPI woodfree paper (basis weight 64g / m 2 , A4 size) <2> Mondi plain paper (basis weight 90 g / m 2, A4 size) <3> Oji Paper OK Top Coat + T-mesh (basis weight 73.3g / m 2 , A4 size) <4> Oji Paper OK Top Coat + Y-mesh (basis weight 73.3 g / m 2 , A4 size)

[0335] Thereafter, the occurrence of paper wrinkles, image peeling, and paper jamming was visually observed and evaluated according to the following evaluation criteria.

[0336] (Evaluation criteria) A: There were no paper jams or wrinkles with any of the paper types, and no image peeling was observed. B: A type of paper that has wrinkles and peeling of images. C: Paper wrinkles and image peeling occur on two types of paper. D: Paper wrinkles or image peeling occurs with three or more types of paper, or paper jams occur.

[0337] [Table 4]

[0338] (E.2) Examples 12 to 18 and Comparative Examples 7 to 10 An image forming apparatus "Accurio Press C4070" manufactured by Konica Minolta, Inc., having a configuration as shown in FIG. 1 of JP-A 2007-240921, was equipped with a fixing device that was appropriately modified to achieve the combination shown in Table V. Developer 1 was loaded as the developer.

[0339] Long-term printing was carried out by printing 300,000 sheets on a recording medium at a printing rate of 5% coverage under conditions of a temperature of 23°C and 50% RH.

[0340] After long-term printing, 10 sheets were printed on the following four types of recording media at a print rate of 20% coverage. <Recording media type> <1> NPI woodfree paper (basis weight 64g / m 2 , A4 size) <2> Mondi plain paper (basis weight 90 g / m 2 , A4 size) <3> Oji Paper OK Top Coat + T-mesh (basis weight 73.3g / m 2 , A4 size) <4> Oji Paper OK Top Coat + Y-mesh (basis weight 73.3 g / m 2 , A4 size)

[0341] Thereafter, the occurrence of paper wrinkles, image peeling, and paper jamming was visually observed and evaluated according to the following evaluation criteria.

[0342] (Evaluation criteria) A: There were no paper jams or wrinkles with any of the paper types, and no image peeling was observed. B: A type of paper that has wrinkles and peeling of images. C: Paper wrinkles and image peeling occur on two types of paper. D: Paper wrinkles or image peeling occurs with three or more types of paper, or paper jams occur.

[0343] [Table 5] F. Overall Review As is clear from Tables IV and V, in the comparative examples, all of the conveying performance ratings were D, whereas in the examples, all of the conveying performance ratings were A, B, or C, indicating that the examples are superior to the comparative examples.

[0344] While embodiments of the present invention have been described and illustrated in detail above, the disclosed embodiments are made for purposes of illustration and example only, and not limitation, and the scope of the invention should be construed in terms of the appended claims. [Explanation of symbols]

[0345] 1. Image forming device 3 Paper cassette 4 Feed roller 5 Transport roller pair 6 Timing Roller Pair 7 Conveyor belt 8 Discharge Roller Pair 9. Paper output tray 10 Image forming unit 11 Feeding section 12 Fixing unit 13 Control section 14 Control Unit 15Y, 15M, 15C, 15K Image Formation Unit 16 Intermediate transfer belt 17 Primary transfer roller 18 Secondary transfer roller 18a Secondary transfer position 18A Primary transfer roller and opposing roller 21 Photoreceptor 22 Charging section 23 Exposure section 24 Development section 25 Cleaner 30 Fixing nip 31 Fixing belt 311 Inner surface of fixing belt 312 Outer surface of fixing belt 313 Space 31α 1st position 31β 2nd position 32 Pressure pad 33 Guide member 339 Groove 34 Support member 35 heated roller 35a Support 35b Elastic member 36 Heater 37 Lubricant application member 38 Bypass route section 380 Flat sponge body 381 Plate-shaped support that sandwiches the sponge body from both sides in the thickness direction 382 Plate-shaped support that sandwiches the sponge body from both sides in the thickness direction 385 Upper edge of sponge body (recovery part) 386 Lower edge of sponge body (supply part) 39 Pressure Roller 391 outer surface of pressure roller 39a Shaft body 399 Axial center 39b Elastic layer 39c Release layer 40 Drive motor 41 Temperature Sensor 42 Torque sensor 90 Fixing device 91 Heating Roller 91A Core metal 91B Elastic layer 91C Release layer 92 Pressure roller 92A Core metal 92B Elastic layer 92C Release layer 93 Guide member 101 Air nozzle 141 CPU 142 Network I / F section 143 ROM 144 RAM 145 Bypass path heating mode execution unit G. Lubricant S, P sheets, recording media H Halogen heater N Nip

Claims

1. An image forming apparatus including a support, an elastic member that is in close contact with the support, an endless belt, and a nip portion, the nip portion is formed by the elastic member and the endless belt, a support body that is in close contact with the elastic member that is pressed in the nip portion is made of an aluminum alloy containing silicon, and The silicon content in the aluminum alloy is within the range of 0.8 to 12.0 mass%. An image forming apparatus characterized by:

2. The endless belt is a belt for transporting a recording medium, and At least one of the nip portions is formed by the elastic member and a belt that transports the recording medium.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

3. The copper content in the aluminum alloy is 1.1 mass% or less.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

4. The nip portion is formed by the endless belt and two rotating bodies that face each other with the endless belt sandwiched therebetween.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

5. a support member provided on the inner side of the endless belt and in close contact with the elastic member pressed at the nip portion; A pressure rotating body is provided on the outer side of the endless belt to press the elastic member at the nip portion.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

6. A transfer means is provided, The nip portion is formed by a member that constitutes the transfer means.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

7. A fixing means is provided, The nip portion is formed by a member that constitutes a fixing means.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

8. The fixing means includes a heating member.

8. The image forming apparatus according to claim 7,

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