JP4840913B2 - Endless belt and image forming apparatus - Google Patents

Description

  The present invention relates to an endless belt and an image forming apparatus, and more particularly to an endless belt capable of forming a high-quality image over a long period of time and an image forming apparatus including the endless belt.

  In an electrophotographic image forming apparatus, an endless belt formed of a thermoplastic resin or the like is used instead of or in addition to a metal drum body or an elastic roller. Examples of such endless belts include a transfer belt, an intermediate transfer belt, a transfer conveyance belt, a conveyance belt, a fixing belt, and a development belt. These endless belts are usually stretched around a plurality of support rollers, and always travel on an endless track in a state where tension is applied.

  However, a conventional endless belt may be stretched when stretched between a plurality of support rollers. For example, a fluororesin endless belt made of a resin composition having a small initial elastic modulus, which is made by blending carbon black with fluororesin, stretches in the circumferential direction at an early stage when stretched on a support roller. End up. In addition, since the endless belt is usually stretched on the support roller for a long period of time, the endless belt made of fluororesin is stretched even if it is stretched at an early stage. The amount gradually increases. On the other hand, an endless belt made of a polycarbonate resin made of a resin composition having a relatively high initial elastic modulus, which is made by blending carbon black with polycarbonate resin, can be quickly introduced in the circumferential direction even when stretched around a support roller. Although it is rarely stretched, the elastic modulus gradually decreases in a state of being stretched on the support roller over a long period of time, and gradually stretches in the circumferential direction.

  When an endless belt disposed in an image forming apparatus or the like is stretched in the circumferential direction, the endless belt cannot be maintained in a tensioned state with a plurality of support rollers, and the traveling endless belt gradually meanders. And / or become wavy. When the endless belt runs meandering and / or wavyly, the position accuracy of the running endless belt decreases, for example, the electrostatic latent image is not transferred to a predetermined position of the endless belt, and a high-quality image is formed over a long period of time. Can not do. In particular, when an endless belt disposed in a tandem type color image forming apparatus or the like that forms a full color image by sequentially superimposing a plurality of color developers on the endless belt is stretched in the circumferential direction, the static image transferred to the endless belt is transferred. The positions at which the electrostatic latent images are superimposed do not exactly match, and the color shift, image shift, etc. of the formed image become significant, making it impossible to form a high quality image. Further, when the endless belt is stretched and the meandering and / or undulation becomes intense, the endless belt may come off the support roller.

As endless belts that can solve these problems, for example, “resin seamless belt characterized by a tensile creep elastic modulus of 10,000 kgf / cm ² or more” (see Patent Document 1) and “creep” A belt member ”(see Patent Document 2) characterized in that the elastic modulus is 120 MPa or more, the difference between the maximum value and the minimum value of the wall thickness in the circumferential direction is 50 μm or less, and is made of a thermoplastic resin. Proposed. As described above, the seamless belts and belt members of Patent Documents 1 and 2 are seamless belts and belt members with low elongation, which are formed for the purpose of suppressing the stretching of the seamless belts and belt members that are originally stretched. For example, as shown in Example 1 and Example 2 of Patent Document 1, the seamless belt of Patent Document 1 has a tensile creep elastic modulus (50 ° C., 100 hour value) having an initial tensile elastic modulus (50 ° C., 1 Therefore, if the seamless belt is stretched over the support roller with a predetermined tension for a long time, it can be easily predicted that the seamless belt will be stretched.

  However, the image forming apparatus is in a state of being stretched between a plurality of support rollers for a long period of time after the endless belt is mounted and assembled before use. Therefore, when the conventional endless belt is stretched around a plurality of support rollers, even if the amount of stretching is small, the conventional endless belt is gradually stretched over time, until the image forming apparatus is used, and / or Thereafter, it may not be possible to maintain the state of being stretched on the support roller with a predetermined tension over a long period of time.

  Therefore, the endless belt is provided in the image forming apparatus and is supported on the plurality of support rollers over a long period of time, during use of the image forming apparatus, and / or for a long period thereafter. In order to form a high-quality image over a long period of time, it is required to be stretched with a predetermined tension.

JP-A-11-115066 JP 2003-206046 A

  An object of the present invention is to provide an endless belt capable of forming a high-quality image over a long period of time and an image forming apparatus including the endless belt.

As means for solving the problems,
Claim 1 is formed in a cyclic form with a polyamideimide resin composition through a secondary solvent removal step under an oxygen concentration of 5% or less, the residual solvent amount is 0.65% by mass or less, and a stress of 4 MPa is applied. Is an endless belt whose tensile strain rate after 100 hours is smaller than the tensile strain rate at the initial stage of stress,
Claim 2 is the endless belt according to claim 1, wherein the tensile strain rate after 100 hours is 0.3% or less,
Claim 3 is the endless belt according to claim 1 or 2, wherein the tensile creep modulus at 100 hours after applying a stress of 4 MPa is larger than the tensile creep modulus at the initial stage of stress,
Claim 4 is the endless belt according to claim 3, wherein the tensile creep modulus after 100 hours is 1,000 MPa or more,
Claim 5 is the endless belt according to any one of claims 1 to 4 , wherein the polyamideimide resin composition includes a conductivity-imparting agent .
A sixth aspect of the present invention is an image forming apparatus including the endless belt according to any one of the first to fifth aspects ,
Claim 7 is a manufacturing method of an endless belt for manufacturing the endless belt according to any one of claims 1 to 5, wherein the polyamideimide resin composition is formed into a ring shape, and the obtained molded body is formed into 5 pieces. It is a manufacturing method of the endless belt which implements a secondary solvent removal process under oxygen concentration of% or less .

  The endless belt according to the present invention has a tensile strain rate after 100 hours after applying a stress of 4 MPa, which is smaller than the tensile strain rate at the initial stage of stress. The stretch amount stretched on the roller and stretched at an early stage gradually decreases, and when the image forming apparatus is used and / or for a long period thereafter, for example, after 100 hours from the stretch on the support roller, The stretch amount is almost canceled out, and it is possible to realize a state in which the stretching is stretched between the plurality of support rollers with a predetermined tension. Therefore, according to the present invention, an endless belt capable of forming a high-quality image over a long period of time can be provided.

  Further, according to the present invention, since the endless belt according to the present invention is provided, an image forming apparatus capable of forming a high-quality image over a long period of time can be provided.

  Hereinafter, an endless belt 1 as an example of the present invention will be described with reference to the drawings. As shown in FIG. 1, the endless belt 1 according to the present invention is formed in an annular shape from a resin composition described later. As shown in FIG. 1, the endless belt 1 has a single layer structure, but may have a multilayer structure in which two or more layers are laminated. The thickness of the endless belt 1 is not particularly limited, but usually, for example, preferably 0.03 to 1 mm, more preferably 0.05 to 0.2 mm, and about 0.07 to 0.14 mm. Is particularly preferred. If the thickness of the endless belt 1 is less than 0.03 mm, the mechanical strength of the endless belt 1 may decrease. May be inferior. The endless belt 1 is formed so as to have a desired inner diameter and outer diameter, and a desired width according to the interval between a plurality of stretched rollers.

  This endless belt 1 has a characteristic that the tensile strain rate after 100 hours after applying a stress of 4 MPa is smaller than the tensile strain rate in the initial stage of stress. Here, since the stretching in the endless belt 1 is normally arranged in the image forming apparatus in a state of being stretched on the support roller for a long period of time, the tensile strain after a long period of time is longer than the tensile strain rate at the initial stage of stress. It is appropriate to evaluate by rate. In the present invention, the tensile strain is evaluated 100 hours after the stress is applied.

  When the endless belt 1 has a tensile strain rate after 100 hours smaller than the tensile strain rate in the initial stage of stress, the endless belt 1 is stretched in the circumferential direction by being stretched around a plurality of support rollers with a predetermined tension. When the state of being stretched on the roller is extended for a long period of time, the amount of stretching in the circumferential direction becomes small, and a state of being stretched on the support roller with a predetermined tension can be realized gradually. Therefore, according to the endless belt 1 having such characteristics, it is possible to prevent color shift, image shift, and the like of the formed image when disposed in the image forming apparatus, and to achieve high quality and high resolution. Images can be formed over a long period of time. The tensile strain rate after 100 hours is preferably 70% or less of the tensile strain rate at the initial stage of stress in that a high-quality and high-resolution image can be formed over a longer period of time. % Or less is more preferable, a value of 25% or less is further preferable, and a value of 15% or less is particularly preferable.

  Here, the tensile strain rate 100 hours after applying the stress is the tensile strain rate measured 100 hours after applying the predetermined stress, and the tensile strain rate at the initial stage of the stress is applied with the predetermined stress. It is the tensile strain rate measured one minute after.

  The tensile strain rate is measured as follows. First, an endless belt having a width of 25 mm and a thickness of 0.1 mm is prepared. Alternatively, when an endless belt having this size cannot be prepared, the width of the endless belt as a test specimen is adjusted so that the stress applied to the endless belt converted to 25 mm in width and 0.1 mm in thickness is 4 MPa. In consideration of the thickness, the stress applied to the endless belt is calculated. Next, under an environment of 40 ° C., the distance between the marked lines is set to 50 mm, the endless belt is subjected to the stress of 4 MPa or the calculated stress, the stress applied to the endless belt is adjusted to 4 MPa, and the stress is applied. The tensile strain is measured after 1 minute (initial stress) and after 100 hours. Other than the above conditions, the method and conditions described in JIS K7115 are followed. In addition, the measurement of a tensile strain rate can also be measured using the test piece cut out in the circumferential direction from the endless belt.

  The endless belt 1 preferably has a tensile strain of 0.3% or less after 100 hours. When the tensile strain rate after 100 hours is 0.3% or less, the stretch amount of the endless belt 1 stretched around the support roller can be almost canceled after 100 hours, and the stretch is stretched around the support roller with a predetermined tension. Can be realized. The tensile strain rate after 100 hours is more preferably 0.2% or less, more preferably 0.1% or less, in that the state of being stretched on the support roller with a predetermined tension can be realized more reliably. More preferably, it is 0.05% or less. The lower limit of the tensile strain after 100 hours is ultimately 0%, but is substantially about 0.001%, for example.

  The endless belt 1 preferably has a characteristic that the tensile creep elastic modulus after 100 hours after applying a stress of 4 MPa is larger than the tensile creep elastic modulus in the initial stage of the stress.

  When the endless belt 1 has a tensile creep elastic modulus after 100 hours that is larger than the tensile creep elastic modulus in the initial stage of stress, the endless belt 1 is stretched around a plurality of support rollers with a predetermined tension and stretched in the circumferential direction. When the state of being stretched on the support roller lasts for a long period of time, the amount of stretching in the circumferential direction becomes small, and the state of being stretched on the support roller with a predetermined tension can be realized gradually. Therefore, according to the endless belt 1 having such characteristics, color misalignment, image misalignment, and the like of the formed image can be more effectively prevented when disposed in the image forming apparatus, and high quality. In addition, a high-resolution image can be formed over a long period of time. The tensile creep modulus after 100 hours is 1.2 times or more than the tensile creep modulus at the initial stage of stress in that a high-quality and high-resolution image can be formed over a longer period of time. It is preferably 4 times or more, more preferably 7 times or more. The upper limit of the tensile creep elastic modulus after 100 hours is not particularly limited, and is, for example, about 20 times the tensile creep elastic modulus at the initial stage of stress.

  Here, the tensile creep elastic modulus in the initial stage of stress is the tensile creep elastic modulus measured one minute after applying the predetermined stress. The tensile creep modulus is measured in the same manner as the tensile strain rate.

  The endless belt 1 preferably has a tensile creep modulus after 100 hours of 1,000 MPa or more. If the tensile creep elastic modulus after 100 hours is 1,000 MPa or more, the stretch amount of the endless belt 1 stretched around the support roller can be almost offset after 100 hours, and the stretch tension stretches around the support roller with a predetermined tension. Can be realized. In view of further enhancing this effect, the tensile creep modulus after 100 hours is more preferably 4,000 MPa or more, and particularly preferably 5,000 MPa or more. The upper limit of the tensile creep modulus after 100 hours is not particularly limited, and is, for example, about 20,000 MPa.

  The endless belt 1 preferably has a tensile creep modulus at an initial stress of 1,000 MPa or less. When the tensile creep elastic modulus in the initial stage of stress is 1,000 MPa or less, the stretch amount of the endless belt 1 can be reduced even in the initial stage of the stress. As a result, the tensile strain modulus and the tensile creep elastic modulus after 100 hours are reduced. It can be easily adjusted to the desired value. The tensile creep elastic modulus at the initial stage of stress is more preferably 900 MPa or less, further preferably 850 MPa or less, and particularly preferably 800 MPa or less. The lower limit of the tensile creep elastic modulus at the initial stage of the stress is that the endless belt 1 can be stretched to prevent the tension from being lowered when the endless belt 1 is stretched on the support roller. It is preferably 650 MPa, more preferably 700 MPa, and particularly preferably 750 MPa in that it can be prevented from idling.

  The endless belt 1 preferably has a residual solvent amount of 0.65% by mass or less from the viewpoint of realizing the above-described tensile strain rate characteristics. The solvent residual amount is more preferably 0.5% by mass or less, further preferably 0.3% by mass or less, in that the tensile strain ratio characteristic can be easily realized. It is particularly preferable that the content is not more than mass%. The amount of residual solvent in the endless belt 1 is determined by immersing a sample cut out from the endless belt 1 in ethanol or the like for a predetermined time to extract the residual solvent in the endless belt 1, and gas chromatography-mass spectrometry (GC-MS) Can be measured.

  The endless belt 1 having the above characteristics is formed by molding a resin composition. The resin composition is preferably a resin composition having a certain level of strength and containing a single resin or a plurality of types of resins that are resistant to repeated deformation and is highly flexible, and is contained in such a resin composition. Examples of the resin used include polyester resins such as polyamideimide resin, polyimide resin, polyamide resin, aramid resin, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), and cross-linked polyester resin. , Polysulfone resin, polyether sulfone resin, polyether ether ketone resin (PEEK), epoxy resin, melamine resin and the like. Among these, polyamideimide resin, polyimide resin, and polyamide resin are preferable, polyamideimide resin is more preferable, and aromatic polyamideimide resin is particularly preferable for the above-described tensile strain because the characteristics of the tensile strain rate can be realized. It is preferable in that the characteristics of the rate can be easily realized and the mechanical properties such as strength, flexibility, dimensional stability and heat resistance are excellent in a well-balanced manner.

  The aromatic polyamideimide resin can be produced by a diisocyanate method in which a tricarboxylic acid anhydride and a diisocyanate compound are reacted, and is excellent in terms of availability of raw materials, reactivity, and a small amount of byproducts. In addition to the aromatic polyamideimide resin produced by the diisocyanate method, an aromatic polyamideimide resin produced using a diamine compound instead of the diisocyanate compound can be used as long as the polycondensation reaction can be suitably advanced. preferable. An aromatic polyamideimide resin obtained using a diamine compound has a high Young's modulus and is suitable as a resin contained in the resin composition forming the endless belt 1. Moreover, the aromatic polyamide-imide resin in which part of the tricarboxylic acid anhydride is replaced with tetracarboxylic dianhydride to increase the imide bond is excellent in moisture resistance. The aromatic polyamideimide resin can be easily synthesized by reacting in an appropriate solvent under normal pressure and at normal temperature or under heating.

  The tricarboxylic acid anhydride is preferably an aromatic tricarboxylic acid anhydride, such as trimellitic acid anhydride, 3,4,4′-diphenyl ether tricarboxylic acid anhydride, 3,4,4′-benzophenone tricarboxylic acid anhydride. 2,3,5-pyridinetricarboxylic acid anhydride, naphthalenetricarboxylic acid anhydride, and derivatives thereof. These acid anhydrides can be used singly or in combination of two or more.

  Examples of the tetracarboxylic dianhydride used in place of a part of the tricarboxylic acid anhydride include pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3, 3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2, 2'-bis (3,4-dicarboxyphenyl) propane dianhydride, bis (3,4-dicarboxyphenyl) sulfonic dianhydride, perylene-3,4,9,10-tetracarboxylic dianhydride Bis (3,4-dicarboxyphenyl) ether dianhydride, ethylenetetracarboxylic dianhydride, and derivatives thereof. These tetracarboxylic dianhydrides can be used alone or in combination of two or more.

  Preferred examples of the diisocyanate compound include aromatic diisocyanate compounds. In addition, as the diisocyanate compound, an aliphatic diisocyanate compound and / or an alicyclic diisocyanate compound, or amines that are derivatives thereof can be used together with or in place of the aromatic diisocyanate compound.

  Examples of the aromatic diisocyanate compound include m-phenylene diisocyanate, p-phenylene diisocyanate, diphenylmethane-4,4′-diisocyanate, 4,4′-diisocyanate diphenyl ether, 4,4′-diisocyanate diphenyl sulfone, and 4,4′-diisocyanate. Biphenyl, 3,3′-dimethyl-4,4′-diisocyanate biphenyl, 2,4-toluene diisocyanate, xylylene diisocyanate and the like can be mentioned. Diamines that are derivatives of these aromatic diisocyanate compounds can also be used as raw materials. Examples of the aliphatic diisocyanate compound include ethylene diisocyanate, propylene diisocyanate, and hexamethylene diisocyanate. Examples of the alicyclic diisocyanate compound include 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and the like. Among these diisocyanate compounds, considering the heat resistance, mechanical properties, solubility, and the like of the endless belt 1, 60% by mass or more, preferably 70% by mass or more of all the diisocyanate compounds used is diphenylmethane-4,4. It is preferable to use diamines that are '-diisocyanate, 2,4-toluene diisocyanate, 3,3'-dimethyl-4,4'-diisocyanate biphenyl, isophorone diisocyanate, or derivatives thereof. Furthermore, considering the dimensional stability of the endless belt 1, 70% by mass or more of all diisocyanate compounds used may be diphenylmethane-4,4′-diisocyanate or its derivative 4,4′-diaminodiphenylmethane. preferable.

  As the solvent used in the polycondensation reaction for synthesizing the aromatic polyamideimide resin, a polar solvent is preferable in terms of solubility, and an aprotic polar solvent is particularly preferable in consideration of reactivity. Examples of aprotic polar solvents include N, N-dialkylamides, and examples of N, N-dialkylamides include N, N-dimethylformamide, N, N-dimethylacetamide, N, N- Examples include diethylformamide, N, N-diethylacetamide, and N, N-dimethylmethoxyacetamide. Further, as a polar solvent, N-methyl-2-pyrrolidone, pyridine, dimethyl sulfoxide, tetramethylene sulfone, dimethyltetramethylene sulfone, and the like are also preferable. These solvent can be used individually by 1 type or in mixture of 2 or more types.

  When the resin composition requires a certain degree of conductivity, such as a transfer / conveyance belt, for example, a conductivity imparting agent is added to form a conductive resin composition. The conductivity-imparting agent contained in the conductive resin composition is composed of various carbon blacks such as furnace black, acetylene black and ketjen black, graphite powder such as natural graphite, artificial graphite and expanded graphite, metal or alloy, etc. Examples include needle-like, spherical, plate-like, and irregular powders, ceramic powders, and various particles whose surfaces are metal-plated. Among these, carbon black is preferable in that the particle size, conductivity, affinity with resin, and the like are excellent in a balanced manner. In addition, the carbon black is more preferably an oxidized carbon black to which a carboxy group, a hydroxy group or the like has been added by an oxidation treatment in terms of improving the affinity with the resin, and an oxidized carbon black having a pH of 6 or less is also preferred. The conductivity-imparting agent is preferably spherical or indefinite, and its size is preferably about 0.01 to 10 μm.

The addition amount of the conductivity imparting agent may be appropriately adjusted depending on the conductivity and particle size of the conductivity imparting agent, the conductivity required for the endless belt 1, and the like. It is preferable that it is 1-25 mass% with respect to a total of 100 mass% with a property imparting agent, and it is more preferable that it is 5-20 mass%. When the addition amount of the conductivity imparting agent is less than 1% by mass, the developed conductivity may be small. On the other hand, when the addition amount of the conductivity imparting agent exceeds 25% by mass, the mechanical strength of the endless belt 1 is increased. May decrease. In order to disperse the conductivity-imparting agent in the resin, a known method can be appropriately selected. Examples of the known method include a mixing roll, a pressure kneader, an extruder, a three-roll, a homogenizer, a ball mill, and a bead mill. And a mixing method using. The required conductivity is, for example, a volume resistance value of 10 ¹¹ Ω · cm.

  The resin composition and the conductive resin composition may contain other components in addition to the resin or the resin and the conductivity-imparting agent as long as the object of the present invention is not impaired. Examples of other components include silicone compounds, fluorine organic compounds, coupling agents, lubricants, antioxidants, plasticizers, colorants, antistatic agents, anti-aging agents, reinforcing fillers, reaction aids, Examples include various additives such as reaction inhibitors, other resins, solvents, and the like.

  Next, a method for manufacturing the endless belt 1 according to the present invention will be described. In order to manufacture the endless belt 1, first, the resin composition is formed into an annular shape by a known forming method. For example, when a thermoplastic resin is selected as the resin contained in the resin composition forming the endless belt 1, when a thermosetting resin is selected as the resin by centrifugal molding, extrusion molding, injection molding, or the like The endless belt 1 can be formed by centrifugal molding, RIM molding, or the like. Among these molding methods, centrifugal molding is preferable in that it can be applied regardless of the material and is excellent in thickness accuracy.

  When the endless belt 1 is molded by centrifugal molding, the resin composition forming the endless belt 1 is preferably adjusted to have a viscosity at molding of 50,000 mPa · s or less. When the viscosity exceeds 50,000 mPa · s, it may be difficult to produce the endless belt 1 having a uniform thickness. The lower limit of the viscosity of the resin composition is not particularly limited, but is preferably 10 mPa · s or more. When the viscosity of the resin composition is out of the above range, the viscosity of the resin composition can be adjusted within the above range by adjusting the amount of the solvent added. As a solvent, the solvent used for the polycondensation reaction which synthesize | combines the said aromatic polyamideimide resin is mentioned.

  According to centrifugal molding, a resin composition that exhibits fluidity by containing a solvent is poured into a cylindrical mold, and the mold is rotated to form a resin composition layer on the inner peripheral surface of the mold by centrifugal force. The endless belt substrate is manufactured by uniformly spreading and drying and removing the solvent from the resin composition layer. Various metal pipes can be used for the mold. As a suitable mold, the inner peripheral surface of the mold is mirror-polished, and the inner peripheral surface that has become the mirror surface is subjected to a release treatment with a release agent such as fluororesin or silicone resin, and the formed endless belt is internally A metal tube that can be easily removed from the peripheral surface can be mentioned.

  When a polyamideimide resin is selected as the resin contained in the resin composition, in addition to the above-described centrifugal molding, a polyamic acid obtained by partially polymerizing a tricarboxylic acid anhydride and a diisocyanate compound, which are raw materials of the polyamideimide resin, is used. Is applied to the inner and outer peripheral surfaces of the mold by a dipping method, a centrifugal method, a coating method, etc., or is developed into a cylindrical shape by an appropriate method such as filling the casting mold with the polyamic acid solution. The developed layer is dried to form a belt shape, and the molded product is heat-treated to convert the polyamic acid to an imide and recover from the mold (Japanese Patent Laid-Open No. 61-95361, The endless belt 1 can also be manufactured according to Japanese Patent Application Laid-Open No. 64-22514 and Japanese Patent Application Laid-Open No. 3-180309.

  The solvent is removed from the resin composition layer developed on the inner peripheral surface of the mold to produce an endless belt substrate. Here, the solvent to be removed is a solvent contained in the layer of the resin composition developed on the inner peripheral surface of the mold. For example, in addition to the solvent used when adjusting the viscosity of the resin composition And a solvent used when synthesizing the aromatic polyamideimide resin. Examples of the treatment for removing the solvent from the resin composition layer developed on the inner peripheral surface of the mold include heat treatment. To remove the solvent to a high degree, the following primary solvent removal step and secondary solvent are used. It is preferable to perform a solvent removal treatment comprising a removal step.

  In the primary solvent removal step, molding is performed while removing the solvent from the layer of the resin composition developed on the inner peripheral surface of the mold by rotating the mold, and the layer of the resin composition is made into a film-like molded body. In the primary solvent removal step, the solvent is removed by passing hot air of 40 to 150 ° C. through the mold for 5 to 60 minutes while rotating the mold. When the hot air temperature exceeds 150 ° C. and / or when the heating time exceeds 60 minutes, the molded film-like molded body may be oxidized.

  In the secondary solvent removal step, the film-like molded body formed in the primary solvent removal step is taken out from the centrifugal molding machine together with the mold, heated together with the mold, and the solvent is highly removed from the film-like molded body. A substrate is used. For example, when using a heater such as a hot air dryer or oven, the film-like molded body may be heated together with the mold at 200 to 300 ° C. for 1 to 3 hours, and when a superheated steam furnace is used. What is necessary is just to heat a film-form molded object for 0.5 to 1 hour with 200-300 degreeC superheated steam with the metal mold | die. In this way, the solvent in the film-shaped molded body can be removed to a high degree.

  In the secondary solvent removal step, maintaining the oxygen concentration at 5% or less in the heating atmosphere does not oxidize the film-like molded body and / or endless belt substrate, and realizes the above-described tensile strain rate characteristics. It is preferable at the point which can do. The oxygen concentration is more preferably 3% or less, and particularly preferably 1% or less, from the viewpoint that the tensile strain characteristic can be easily realized. To keep the oxygen concentration in the heating atmosphere at 5% or less, replace the inside of the heating device with a gas that does not contain oxygen or a gas with low oxygen content, such as an inert gas such as superheated steam, nitrogen gas, or rare gas. do it. In addition, when using a hot air dryer, the hot air injected can also be made into the said inert gas. The oxygen concentration can be measured by a known oxygen concentration meter, for example, “direct insertion type integrated zirconia oxygen concentration meter / high temperature hygrometer, ZR202G” (manufactured by Yokogawa Electric Corporation).

  Thus, after highly removing a solvent from a film-form molded object, an endless belt base | substrate is taken out and it cools. When the endless belt base is allowed to cool together with the mold, the endless belt base made of the resin composition can be removed due to the difference in thermal expansion coefficient between the mold and the endless belt base. Both end portions of the removed cylindrical endless belt base are removed and cut into a predetermined width, whereby the endless belt 1 is manufactured.

  The endless belt 1 manufactured in this manner has a characteristic that the tensile strain rate after 100 hours after applying a stress of 4 MPa is smaller than the tensile strain rate at the initial stage of the stress, so that a plurality of support rollers can be used for a long time. When stretched over the endless belt 1, the stretch amount of the endless belt 1 gradually decreases, and the endless belt 1 is stretched with a predetermined tension on a plurality of support rollers. As a result, a high-quality image is formed over a long period of time. be able to.

  The endless belt 1 may include a guide member that extends in the circumferential direction on at least one side of the inner peripheral surface thereof. The guide member guides the endless belt 1 so that the endless belt 1 travels without meandering and / or undulating travel. The guide member is usually formed into an elongated shape such as a saddle shape, a rail shape, a belt shape, or the like with a high elastic modulus material such as a biaxially stretched polyester resin, and is adhered to the endless belt 1 with an adhesive or a double-sided tape.

  The endless belt 1 according to the present invention can be used for applications such as an image carrier base, development, transfer body conveyance, and fixing for various image forming apparatuses. FIG. 2 shows a developing device in which the endless belt 1 is incorporated as a transfer conveyance belt. The endless belt 1 is stretched around a plurality of support rollers 5 as a transfer conveyance belt 30.

  As shown in FIG. 2, the image forming apparatus 10 is a tandem type color image forming apparatus in which a plurality of image carriers 11 provided in each color developing unit are arranged in series on a transfer conveyance belt 30. Developing units BK, C, M, and Y are arranged in series on the transfer conveyance belt 30. Each of these developing units is provided with a rotatable image carrier 11 on which an electrostatic latent image is formed, and a charge that is provided in contact with the image carrier 11 or at a predetermined interval to charge the image carrier 11. A means 12; an exposure means 13 for forming an electrostatic latent image on the image carrier 11; and an abutting contact with the image carrier 11 or at a predetermined interval. The developer 22 is supplied to the carrier 11 with a constant layer thickness, and is provided so as to be in pressure contact with the developing means 20 for developing the electrostatic latent image via the transfer conveyance belt 30 below the image carrier 11. Transfer means 14 for transferring the electrostatic latent image developed on the transfer body 16 conveyed by the transfer conveyance belt 30 from the carrier 11, developer 22 remaining on the image carrier 11 without being transferred to the transfer body 16, and the like And a cleaning means 15 for removing water.

  As the image carrier 11, the charging unit 12, the exposure unit 13, the transfer unit 14, and the cleaning unit 15, conventionally known ones can be appropriately selected and used. For example, the image carrier 11 may be, for example, a cylindrical body or a belt body provided with a photosensitive layer formed of organic, amorphous silicon, Se-based alloy, or the like. Examples of the transfer unit 14 include a contact-type charger, a scorotron charger, and a corotron charger. The exposure unit 13 includes a light source such as a semiconductor laser beam and a light-emitting diode beam, or an optical device including a light source and a polygon mirror. Examples of the cleaning unit 17 include a blade and a roller.

  As shown in FIG. 2, the developing means 20 has an opening at a position facing the image carrier 11, a developer storage portion 21 that stores the developer 22, and an opening portion of the developer storage portion 21. A rotatable developer carrier 23 provided in contact with the image carrier 11 or at a predetermined interval, and supplying the developer 22 with a constant layer thickness to the image carrier 11; Provided above the developer carrier 23 is provided with a developer regulating member 24 that contacts the developer carrier 23 to regulate the layer thickness of the developer 22 and charges the developer 22 by frictional charging. .

  The developer 22 may be a dry developer or a wet developer as long as it can be charged by friction and can be fixed to the transfer body 16, and may be a non-magnetic developer or a magnetic developer. Each of the developing units BK, C, M, and Y stores a black developer, a cyan developer, a magenta developer, and a yellow developer in the developer storage unit 21. The developer carrier 23 and the developer regulating member 24 may be any conventionally known developer carrier and developer regulating member. For example, the developer carrier 23 may be conductive or semiconductive. Examples thereof include a roller having a resin layer, and the developer regulating member 24 may be a resin blade or a metal blade.

  As shown in FIG. 2, the image carrier 11 and the transfer unit 14 in the developing units BK, C, M, and Y are in contact with each other via a transfer conveyance belt 30 that is stretched between two support rollers 5. ing. Then, the transfer body 16 is transported by the transfer transport belt 30 so as to pass through a contact portion between the image carrier 11 and the transfer unit 14. The transfer conveyance belt 30 conveys the transfer body 16 and transfers the developed electrostatic latent image on the image carrier 11 in cooperation with the transfer means 14.

  As shown in FIG. 2, at the bottom of the image forming apparatus 10, a cassette 31 formed by stacking and storing a plurality of transfer sheets as a transfer body 16 is installed, and the transfer sheet in the cassette 31 is a paper feed roller. The sheet is fed out one by one by a process or the like and conveyed onto the transfer conveyance belt 30.

  As shown in FIG. 2, a fixing unit 32 that fixes the developer 22 (electrostatic latent image) transferred to the transfer body 16 is disposed downstream in the transport direction of the transfer body 16 in the image forming apparatus 10. . The fixing means 32 may be a conventionally known fixing means, and for example, a heat roller fixing device such as a heat roller fixing device or an oven fixing device, a pressure fixing device, and a fixing device including a fixing belt may be used. it can.

  The image forming apparatus 10 operates as follows. First, the image carrier 11 of the developing unit BK is uniformly charged by the charging unit 12, and the image is exposed by the exposure unit 13 to form an electrostatic latent image on the surface of the image carrier 11. On the other hand, in the developing unit 20, the black developer 22 is regulated to a desired layer thickness by the developer carrier 23 and the developer regulating member 24 and is charged as desired. Then, the black developer 22 is supplied from the developer carrier 23 to the image carrier 11, and the electrostatic latent image formed on the image carrier 11 is developed and visualized as a developer image. Next, the developer image is transferred onto the transfer body 16 conveyed by the transfer conveyance belt 30 between the image carrier 11 and the transfer unit 14. In this way, the developer image is visualized as a black image on the transfer paper 16.

  Next, similarly to the developing unit BK, the cyan image, the magenta image, and the yellow image are superimposed on the transfer paper 16 in which the developer image is visualized as a black image by the developing units C, M, and Y, respectively. The image is visualized. At this time, since the endless belt 1 according to the present invention is used as the transfer conveyance belt 30, it is possible to prevent the transfer conveyance belt 30 from running meandering and undulating as desired, and onto the transfer paper 16. A cyan image, a magenta image, and a yellow image are superimposed on an accurate position on the visualized black image. As a result, according to the image forming apparatus 10, color unevenness, image misalignment, and the like can be effectively prevented over a long period of time, and a high-quality image can be formed.

  Next, the transfer body 16 on which the color image is visualized is conveyed to the fixing unit 32, and the color image is fixed on the transfer body 16 as a permanent image by the fixing unit 32. In this way, a color image can be formed on the transfer body 16.

  According to the image forming apparatus 10, since a black image, a cyan image, a magenta image, and a yellow image can be superimposed at an accurate position over a long period of time, color unevenness and image misalignment can be prevented as desired over a long period of time. It is possible to form a high-quality and high-resolution image.

  The endless belt 1 according to the present invention has a transfer belt (also referred to as a photosensitive belt) that plays the same role as the image carrier 11 and a developer image visualized by the image carrier 11 once. Transfer (primary transfer), and then transfer (secondary transfer) to the transfer body 16 to transfer the image onto the transfer body. Even if it is incorporated in the image forming apparatus as a developing belt that plays the same role as the belt, the fixing belt used in the fixing device, and the developer carrier, the image forming apparatus 10 can provide high quality as in the case of the transfer conveyance belt. In addition, a high-resolution image can be formed.

  The image forming apparatus 10 is an electrophotographic image forming apparatus. However, in the present invention, the image forming apparatus 10 is not limited to the electrophotographic system, and is, for example, an electrostatic image forming apparatus. Also good. Further, the image forming apparatus 10 is a tandem type color image forming apparatus in which a plurality of image carriers each having a developing unit for each color are arranged in series on a transfer conveyance belt. Even a monochrome image forming apparatus provided with a developing unit may be a four-cycle color image forming apparatus that sequentially repeats primary transfer of a developer image carried on an image carrier onto an endless belt. The image forming apparatus 10 is an image forming apparatus such as a copying machine, a facsimile machine, or a printer.

Example 1
In a reaction vessel, an equivalent amount of trimellitic anhydride and 4,4′-diaminodiphenylmethane are dissolved in N, N-dimethylacetamide and heated to obtain a solid concentration (substantially fully ring-closed polyamideimide). A 28 mass% aromatic polyimideimide solution was obtained. N, N-dimethylacetamide was further added to this solution to prepare a polyamideimide solution having a solid content concentration of 15% by mass and a solid content specific gravity of 1.2. Oxidized carbon black (trade name “Printex 150T”, manufactured by Degussa, pH 5.8, volatile content 10.0%) was added to the obtained polyamideimide solution in a total of 100% by mass of the polyamideimide solution and the oxidized carbon black. The conductive resin composition was prepared by blending in an amount of 10% by mass, and mixing and dispersing in a pot mill for 24 hours. The mold used for molding has an inner diameter of 226 mm, an outer diameter of 246 mm, and a length of 400 mm, and the inner surface of the mold is mirror-polished by polishing. Next, ring-shaped lids (inner diameter: 170 mm, outer diameter: 250 mm) are fitted into the openings at both ends of the mold, the mold is closed, and the conductive resin composition is rotated at a speed of 1,000 rpm. 190 g was injected into the inner periphery of the mold. Next, the mold was rotated at the same speed to uniformly spread the conductive resin composition layer on the inner peripheral surface of the mold. Next, while rotating the mold at the same speed, the temperature around the mold was maintained at 80 ° C. with a hot air dryer, and this state was maintained for 30 minutes to form a film-shaped molded body. Thereafter, the rotation of the mold was stopped, and the entire mold was put into an oven at 250 ° C. for 2 hours to perform a secondary solvent removing step, thereby obtaining an endless belt substrate. The secondary solvent removal step was performed in an atmosphere having an oxygen concentration of 5% (the oxygen concentration was “direct insertion type integrated zirconia oxygen concentration meter / high temperature humidity meter, ZR202G” (manufactured by Yokogawa Electric Corporation). ). Next, the mold was left to cool to room temperature, and the endless belt base was removed from the mold by utilizing the difference in thermal expansion between the mold and the endless belt base. Next, both end portions of the removed endless belt substrate were cut to a width of 240 mm, and an endless belt 1A having an inner diameter of 226 mm and a thickness of 100 μm was produced.

(Example 2)
The secondary solvent removal step was measured using an atmosphere having an oxygen concentration of 5% (the oxygen concentration was “direct insertion type integrated zirconia oxygen concentration meter / high temperature hygrometer, ZR202G” (manufactured by Yokogawa Electric Corporation). 2), an endless belt 1B was produced in the same manner as in Example 1 except that it was dried with superheated steam at 250 ° C. for 1 hour.
(Example 3)
The secondary solvent removal step was measured using an atmosphere having an oxygen concentration of 5% (the oxygen concentration was “direct insertion type integrated zirconia oxygen concentration meter / high temperature hygrometer, ZR202G” (manufactured by Yokogawa Electric Corporation). 1), an endless belt 1C was produced in the same manner as in Example 1 except that it was dried in an oven at 230 ° C. for 2 hours.
Example 4
The secondary solvent removal step was measured using an atmosphere having an oxygen concentration of 5% (the oxygen concentration was “direct insertion type integrated zirconia oxygen concentration meter / high temperature hygrometer, ZR202G” (manufactured by Yokogawa Electric Corporation). 2), an endless belt 1D was produced in the same manner as in Example 1 except that it was dried in an oven at 200 ° C. for 2 hours.

(Comparative Example 1)
An endless belt 1E was produced in the same manner as in Example 1 except that the secondary solvent removal step was not performed.
(Comparative Example 2)
100 parts by mass of polycarbonate resin (trade name “AC3010”, manufactured by Idemitsu Petrochemical Co., Ltd.) and 10 parts by mass of oxidized carbon black (trade name “Printex 150T”, manufactured by Degussa) were mixed into a twin-screw extruder (trade name “ An endless belt 1 </ b> F having a thickness of 150 μm was produced by melt-kneading at 250 ° C. using “Laboplast Mill” (manufactured by Toyo Seiki Co., Ltd.).
(Comparative Example 3)
100 parts by mass of ETFE (ethylene / tetrafluoroethylene = 48/52 (molar ratio)) and 10 parts by mass of oxidized carbon black (trade name “Printex 150T”, manufactured by Degussa) were mixed at 30 ° C. with a Henschel mixer. Thereafter, it was melt kneaded and extruded at 300 ° C. with the twin-screw extruder to produce an endless belt 1G having a thickness of 150 μm.

  From each of the produced endless belts 1 </ b> A to 1 </ b> G, a test specimen was cut out in the circumferential direction to have a width of 25 mm and a length of 10 mm. Next, using a creep tester (trade name “C200”, manufactured by Toyo Seiki Co., Ltd.), in an environment of 40 ° C., the distance between the marked lines was set to 50 mm, and a stress of 4 MPa was applied to each test piece 1 minute later ( In the initial stage of stress and after 100 hours, the tensile strain rate and the tensile creep modulus were measured in accordance with the method and conditions described in JIS K7115. Table 1 shows the measurement conditions and measurement results in Examples and Comparative Examples.

  Three test pieces each having a 50 mg piece were cut out from each of the produced 1A to 1E, and each test piece was immersed in 20 mL of ethanol at 60 ° C. for 24 hours. The residual amount of N, N-dimethylacetamide in the ethanol solution was measured by gas chromatography-mass spectrometry (GC-MS). At the time of measurement, a calibration curve is obtained by measuring in advance the amount of N, N-dimethylacetamide in a standard solution containing 100 ppm and 1000 ppm of N, N-dimethylacetamide in ethanol. The results are shown in Table 1. Since the endless belts F and G do not contain a solvent, the residual solvent amount was not measured.

  Next, each of the endless belts 1 </ b> A to 1 </ b> G was incorporated as a transfer conveyance belt 30 in the tandem type color printer 10 (trade name “MicroLine 9055c” manufactured by Oki Data Corporation) shown in FIG. 2. Each of the endless belts 1A to 1G was incorporated as a transfer conveyance belt 30, and after about 100 hours had passed, 10,000 sheets of A4 paper were printed at a speed of printing 21 sheets / min. Ten thousand A4 sheets printed in this way were taken out every 1,000 sheets, and printed images were confirmed. As a result, in the endless belts 1A to 1D, no image deviation was observed on any A4 paper, and an image was formed with high quality and high resolution, whereas in the endless belts 1E to 1G, all were initial. Image misalignment occurred, and as the number of printed sheets increased, image misalignment occurred, and an image with poor quality was formed.

FIG. 1 is a schematic perspective view showing an endless belt according to an embodiment of the present invention. FIG. 2 is a schematic view showing a tandem color image forming apparatus according to an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Endless belt 10 Image forming apparatus 11 Image carrier 12 Charging means 13 Exposure means 14 Transfer means 15 Cleaning means 16 Transfer body 20 Developing means 21 Developer container 22 Developer 23 Developer carrier 24 Developer regulating member 30 Transfer conveyance Belt 31 Cassette 32 Fixing means BK, C, M, Y Development unit

Claims (7)

After a secondary solvent removal step under an oxygen concentration of 5% or less, the polyamideimide resin composition is formed into a ring shape, the residual solvent amount is 0.65% by mass or less, and 100 hours after applying a stress of 4 MPa. Endless belt whose tensile strain rate is smaller than the tensile strain rate at the initial stage of stress.   The endless belt according to claim 1, wherein the tensile strain rate after 100 hours is 0.3% or less.   The endless belt according to claim 1 or 2, wherein a tensile creep modulus at 100 hours after applying a stress of 4 MPa is larger than a tensile creep modulus at an initial stage of stress.   The endless belt according to claim 3, wherein the tensile creep modulus after 100 hours is 1,000 MPa or more. The endless belt according to any one of claims 1 to 4, wherein the polyamideimide resin composition contains a conductivity imparting agent . An image forming apparatus comprising the endless belt according to claim 1 .   It is a manufacturing method of the endless belt which manufactures the endless belt of any one of Claims 1-5, Comprising: Polyamideimide resin composition is shape | molded cyclically, The oxygen concentration of 5% or less is obtained for the obtained molded object. The manufacturing method of the endless belt which implements a secondary solvent removal process under.

Images