Fixing Belt and Fixing Device

Abstract

To provide a fixing belt and fixing device capable of solving a problem that when removing the air by drawing adhesive, the air can be efficiently removed by increasing an amount of the adhesive applied, but if too much adhesive is applied, excess adhesive remains at a bottom after drawing causing contamination of an inner surface of a fixing member at the end of the drawing; thus a separate process such as cleaning is required; on the other hand, contamination can be prevented by reducing the amount of the adhesive, but efficiency and effect for removing air will fade.SOLUTION: In an endless fixing member comprising at least two layers of a surface layer and a base layer from the outside, defining adhesive volume per unit area required for air evacuation as A; the amount of the adhesive per unit length consumed by drawing as a; and a distance from a top end as x, an adhesive applying amount B in the longitudinal direction is B=A-ax.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a coating device for coating a coating liquid, a coating method for coating a coating liquid, a manufacturing device for a fixing member, a manufacturing method for a fixing member, and a fixing member.

Background Art

[0002] In a fixing device for an electrophotographic apparatus, a fixing roller method has conventionally been common. However, since the heat capacity of the fixing roller is large, it takes a long time to heat, the waiting time at startup is long, and the power consumption is also large. Therefore, in recent years, as an on-demand method with high heat transfer efficiency and fast startup of the apparatus, a fixing device of a belt heating method that heats the toner on the transfer paper by the heat of a heater through a fixing belt having a small heat capacity has been adopted.

[0003] The belt fixing device has, as described in Patent Documents 1 and 2, for example, a ceramic heater as a fixed and supported heating body, a fixing belt as a heat transfer member that slides on the heating body, and an elastic pressure roller as a pressure member that presses against the heating body through the fixing belt to form a fixing nip portion. A recording material carrying an unfixed toner image is sandwiched and conveyed between the fixing belt and the elastic pressure roller in the fixing nip portion, and the unfixed toner image is heat-melted and fixed on the recording material by the heat from the heating body through the fixing belt.

[0004] The basic configuration of the fixing belt includes at least a thin cylindrical base body with a small heat capacity, a silicone rubber elastic layer for applying a uniform pressure to the toner image and the unevenness of the paper during fixing, and a fluororesin release layer for maintaining the releasability from the toner. And there is an adhesive layer for bonding the elastic layer and the surface layer between them, and the configuration is a cylindrical base body, a silicone rubber elastic layer, an adhesive layer, and a fluororesin release layer from the inner layer to the outer layer.

[0005] In the production of such a fixing belt, when coating the release layer on the elastic layer, air may be trapped between the elastic layer and the release layer, resulting in the generation of a portion where there is no adhesive between the release layer and the elastic layer, and thus partial adhesion failure may occur. Therefore, in the process of adhering the release layer to the elastic layer, the following operations are performed: (1) applying an adhesive to the surface of the elastic layer, (2) coating the release layer, and (3) applying pressure from the upper side of the release layer toward the elastic layer to squeeze out the adhesive and remove the excess adhesive. In the process of (3), the trapped air is removed together with the adhesive.

[0006] As other methods, technologies as shown in Patent Documents 1 and 2 have been proposed. In Patent Document 1, an air layer is removed by folding back the end portion. In Patent Document 2, a method of removing the air layer by winding the release layer in a spiral shape is shown.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0008] Although air removal can be achieved by the prior art and the methods described in Patent Documents 1 and 2, these methods also have problems.

[0009] For example, when removing air by handling an adhesive, increasing the application amount of the adhesive can efficiently remove air. However, since too much adhesive is applied, excess adhesive remains at the end of handling, and the adhesive penetrates into the inner surface of the fixing member at the end of handling, contaminating the inner surface. Therefore, a separate process such as cleaning is required. Also, although contamination of the inner surface can be prevented by reducing the amount of adhesive, the effect of air removal is weakened, and the air cannot be removed properly and remains. Therefore, there is a problem that air removal and end contamination are in a trade-off relationship.

[0010] Therefore, an object of the present invention is to optimize the application amount of the adhesive to prevent leakage of the adhesive, enable air removal, and achieve both poor adhesion and adhesive leakage.

Means for Solving the Problems

[0011] As a result of repeated studies by the present inventors for the above object, it has become possible to prevent adhesive leakage during manufacturing by applying the adhesive with a gradient to the application amount of the adhesive from the amount of adhesive required for air discharge and the amount required for adhesion.

[0012] In summary, the present invention has the following features as a method for manufacturing a fixing member and a fixing member. (Feature 1) In an endless fixing member composed of at least two layers, a surface layer and a base layer, from the outside, the amount of adhesive per unit area required for air discharge is A (g / mm), and the amount of adhesive consumed per unit length by handling the adhesive is a (g / mm 2 ), the distance from the upper end is x ( mm ), and when the adhesive application amount B (g / mm) in the longitudinal direction is set, a manufacturing method for a fixing member characterized in that B = A - ax. (Feature 2) A fixing member created using the manufacturing method described in Feature 1.

Effects of the Invention

[0013] According to the present invention, in a fixing belt having a structure of a cylindrical substrate, a silicone rubber elastic layer, an adhesive layer, and a fluororesin release layer from the inner layer to the outer layer, by optimizing the method of applying the adhesive, it is possible to prevent the leakage of the adhesive, remove air, and achieve both poor adhesion and adhesive leakage.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0015] Next, embodiments for carrying out the present invention will be described. However, the scope of the present invention is not limited to only this embodiment, and those modified within the scope not impairing the gist of the present invention are also included in the present invention.

[0016] [1] Schematic Configuration of Image Forming Apparatus; FIG. 1 is a schematic cross-sectional view of the image forming apparatus used in this embodiment. 101 is a photosensitive drum as an image carrier, which is rotationally driven in the counterclockwise direction of the arrow at a predetermined process speed (circumferential speed). The photosensitive drum 101 is charged to a predetermined polarity by a charging device 102 such as a charging roller during its rotation process. Next, the charged processing surface is exposed by the laser beam 103 output from the laser optical system 110 based on the input image information.

[0017] The laser optical system 110 outputs a laser beam 103 modulated (on / off) corresponding to the time-series electrical digital pixel signals of the target image information from an image signal generation device such as an image reading device (not shown), and scans and exposes the surface of the photosensitive drum 101. As a result, an electrostatic latent image corresponding to the image information is formed on the surface of the photosensitive drum 101. 109 is a mirror that deflects the output laser beam 103 from the laser optical system 110 to the exposure position of the photosensitive drum 101.

[0018] Then, the electrostatic latent image formed on the photosensitive drum is visualized with yellow toner by the yellow developing device 104Y among the developing devices 104. This yellow toner image is transferred onto the surface of the intermediate transfer drum 105 at the primary transfer portion T1, which is the contact portion between the photosensitive drum 101 and the intermediate transfer drum 105. Note that the toner remaining on the surface of the photosensitive drum 101 is cleaned by the cleaner 107. The above-described process cycle of charging, exposure, development, primary transfer, and cleaning is similarly repeated to form a magenta toner image (when the developing device 104M operates), a cyan toner image (when the developing device 104C operates), and a black toner image (when the developing device 104K operates).

[0019] In this way, the toner images of each color sequentially formed and stacked on the intermediate transfer drum 105 are collectively secondarily transferred onto the recording material P at the secondary transfer portion T2, which is the contact portion with the transfer roller 106. The toner remaining on the intermediate transfer drum 105 is cleaned by the toner cleaner 108. Note that this cleaner 108 is configured to be able to contact and separate from the intermediate transfer drum 105, and is configured to be in contact with the intermediate transfer drum 105 only when cleaning the intermediate transfer drum 105.

[0020] Also, the transfer roller 106 is also configured to be able to contact and separate from the intermediate transfer drum 105, and is configured to be in contact with the intermediate transfer drum 105 only during secondary transfer. The recording material P that has passed through the secondary transfer portion T2 is introduced into the fixing device 100 as an image heating device and undergoes a fixing process (image heating process) of the unfixed toner image carried thereon. Then, the recording material P that has undergone the fixing process is discharged outside the machine, and a series of image forming operations are completed.

[0021] [2] Schematic configuration of the fixing device; FIG. 2 is a schematic cross-sectional view of the fixing device 100. Reference numeral 1 denotes a cylindrical fixing belt (endless belt) having an elastic layer. Reference numeral 6 denotes a pressure roller as a pressure member that forms a fixing nip portion 14 with the fixing belt. Reference numeral 2 denotes a fixing heater as a heating body, and reference numeral 4 denotes a film guide and heater holder having heat resistance. The fixing heater 2 is fixed along the length of the film guide and heater holder 4 to the lower surface of the film guide and heater holder 4, and is configured such that the heating surface thereof is slidable with respect to the fixing belt 1.

[0022] The fixing belt 1 is externally fitted to this film guide and heater holder 4 with a certain degree of freedom. The film guide and heater holder 4 is made of a highly heat-resistant liquid crystal polymer resin, and serves to hold the fixing heater 2 and to form a shape for separating the fixing belt 1 from the recording material P. The pressure roller 6 has a multilayer structure in which a silicone rubber layer with a thickness of about 3 mm and a PFA resin tube with a thickness of about 40 μm are sequentially laminated on a stainless steel core. Both ends of the core of this pressure roller 6 are rotatably held by bearings between the back side (not shown) and the front side side plates of the apparatus frame 13.

[0023] Above this pressure roller 6, a fixing unit including a fixing heater 2, a film guide and heater holder 4, a fixing belt stay 5, and a fixing belt 1 is installed. This fixing unit is installed parallel to the pressure roller 6 with the fixing heater 2 side facing downward. Both ends of the fixing belt stay 5 are urged against the pressure roller 6 by a pressing mechanism (not shown) with a force of 156.8 N (16 kgf) at one end and a total pressure of 313.6 N (32 kgf). As a result, the lower surface (heating surface) of the fixing heater 2 is pressed against the elastic layer of the pressure roller 6 with a predetermined pressing force via the fixing belt 1, and a fixing nip portion 14 with a predetermined width required for fixing is formed.

[0024] 3 is a thermistor as temperature detection means. The thermistor 3 (heater temperature sensor) is installed on the back surface (the surface opposite to the heating surface) of the fixing heater 2 which is a heat source, and is responsible for the function of detecting the temperature of the fixing heater 2. The pressure roller 6 is rotationally driven at a predetermined peripheral speed in the direction of the arrow. The fixing belt 1 in contact with this is driven by the pressure roller 6 and rotates at a predetermined speed. At this time, the inner surface of the fixing belt 1 is in close contact with the lower surface of the fixing heater 2 and slides while being driven to rotate in the direction of the arrow around the outside of the film guide and heater holder 4.

[0025] A semi-solid lubricant, which will be described later, is applied to the inner surface of the fixing belt 1 to ensure the slidability between the film guide and heater holder 4 and the inner surface of the fixing belt 1. The thermistor 3 is arranged to contact the back surface of the fixing heater 2 and is connected to a control circuit unit (CPU) 10 as a control means via an A / D converter 9. This control circuit unit (CPU) 10 samples the outputs from the respective thermistors at a predetermined cycle and is configured to reflect the temperature information thus obtained in the temperature control. That is, based on the output of the thermistor 3, the control circuit unit (CPU) 10 determines the temperature control content of the fixing heater 2 and controls the energization of the fixing heater 2 by the heater drive circuit unit 11, which is a power supply unit, so that the temperature of the fixing heater 2 becomes the target temperature (set temperature).

[0026] In addition, the control circuit unit (CPU) 10 also plays a role in controlling the fixing belt life estimation sequence, which will be described later, and is connected via the drive motor of the pressure roller 6 and the A / D converter 9. The fixing heater has an alumina substrate and a resistive heating element formed by screen-printing a conductive paste containing a silver-palladium alloy on the substrate to form a film with a uniform thickness of about 10 μm. Further, a glass coat made of pressure-resistant glass is applied thereon to form a ceramic heater.

[0027] FIG. 3 is a schematic view of the fixing belt 1 obtained in this embodiment. 1c is a cylindrical substrate, 1b is a silicone rubber elastic layer disposed on the outer peripheral surface of the cylindrical substrate 1c, and 1a is a fluororesin release layer compounded on the elastic layer. It is disposed between the elastic layer 1b and the release layer 1a via a silicone rubber adhesive layer.

[0028] Specific description will be given below.

[0029] In view of the need for heat resistance and flexural resistance, metals such as stainless steel (SUS), nickel, and nickel alloys are preferably used for the cylindrical substrate 1c. Since the cylindrical substrate 1c needs to have a small heat capacity while having high mechanical strength, the thickness is preferably 20 to 80 μm, more preferably 25 to 50 μm.

[0030] The silicone rubber elastic layer 1b functions as an elastic layer carried on a fixing member to apply a uniform pressure to the toner image and the unevenness of the paper during fixing. In order to exhibit such a function, as the material of the silicone rubber elastic layer 1b, an addition reaction crosslinking type liquid silicone rubber is preferably used because it is easy to process, can be processed with high dimensional accuracy, and does not generate reaction by-products during heat curing. Further, since the elasticity can be adjusted by adjusting the degree of crosslinking according to the type and addition amount of the filler described later.

[0031] Generally, an addition reaction crosslinking type liquid silicone rubber contains an organopolysiloxane having an unsaturated aliphatic group, an organopolysiloxane having active hydrogen bonded to silicon, and a platinum compound as a crosslinking catalyst.

[0032] The organopolysiloxane having active hydrogen bonded to silicon forms a crosslinked structure by reacting with the alkenyl group of the organopolysiloxane component having an unsaturated aliphatic group under the catalytic action of the platinum compound.

[0033] The silicone rubber elastic layer 1b may contain a filler for improving thermal conductivity, reinforcement, heat resistance, etc. on the fixing belt.

[0034] In particular, for the purpose of improving thermal conductivity, the filler is preferably highly thermally conductive. Specifically, inorganic substances, particularly metals, metal compounds, etc. can be mentioned.

[0035] Specific examples of the highly thermally conductive filler include silicon carbide (SiC), silicon nitride (Si3N4), boron nitride (BN), aluminum nitride (AlN), alumina (Al2O3), zinc oxide (ZnO), magnesium oxide (MgO), silica (SiO2), copper (Cu), aluminum (Al), silver (Ag), iron (Fe), nickel (Ni), etc.

[0036] These can be used alone or in combination of two or more. From the viewpoints of handling and dispersibility, the average particle size of the high thermal conductivity filler is preferably 1 μm or more and 50 μm or less. Also, as for the shape, spherical, crushed, plate-like, whisker-like, etc. can be used, but spherical ones are preferred from the viewpoint of dispersibility.

[0037] From the contribution to the surface hardness of the fixing belt and the efficiency of heat conduction to the unfixed toner during fixing, the preferable range of the thickness of the silicone rubber elastic layer is 100 μm or more and 500 μm or less, and particularly preferably 200 μm or more and 400 μm or less.

[0038] As the fluororesin release layer, for example, a resin such as tetrafluoroethylene-perfluoro(alkyl vinyl ether) copolymer (PFA), polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), etc. formed into a tube shape is used. Among the materials exemplified above, PFA is preferred from the viewpoints of moldability and toner releasability.

[0039] The thickness of the fluororesin release layer is preferably 50 μm or less. This is because when laminated, the elasticity of the lower silicone rubber elastic layer can be maintained, and it is possible to suppress the surface hardness of the fixing member from becoming too high.

[0040] The inner surface of the fluororesin tube can be improved in adhesiveness by performing sodium treatment, excimer laser treatment, ammonia treatment, etc. in advance.

[0041] The silicone rubber adhesive layer fixing the PFA tube as the fluororesin release layer to the silicone rubber elastic layer 1b is composed of a cured product of an addition-curing type silicone rubber adhesive coated on the surface of the silicone rubber elastic layer 1b. And the addition-curing type silicone rubber adhesive contains an addition-curing type silicone rubber in which a self-adhesive component typified by a silane having a functional group such as an acryloxy group, a hydrosilyl group (SiH group), an epoxy group, an alkoxysilyl group, etc. is blended.

[0042] Next, by heating with a heating means such as an electric furnace for a predetermined time, the addition-curing type silicone rubber adhesive is cured and adhered, and by cutting both ends to a desired length, a fixing belt as a fixing member of the present embodiment can be obtained.

[0043] On the surface of this cylindrical substrate 1c, a hydrosilyl-based silicone primer "DY39-051 A / B; manufactured by Toray Dow Corning Co., Ltd." was applied and heat-cured at 200°C for 5 minutes. On its outer peripheral surface, an addition reaction cross-linked type liquid silicone rubber with a thickness of 300 μm was applied and heat-cured at 200°C for 30 minutes to form a silicone rubber elastic layer 1b. Further, on its outer peripheral surface, a 20-μm-thick PFA tube was coated as a fluororesin release layer 1a via a silicone adhesive "SE1819 CV A / B; manufactured by Toray Dow Corning Co., Ltd.". Thereafter, the adhesive was extruded through the release layer to perform a coating process.

[0044] FIG. 4 is a schematic diagram showing the handling process of the adhesive. As shown in FIG. 4, after applying the adhesive to cover the release layer, by using a handling ring 21 to press the adhesive from above the release layer while the ring moves downward, the excess adhesive layer between the release layer and the elastic layer can be removed.

[0045] In such a state, when the adhesive is sufficiently applied, the air bitten in when the adhesive is extruded is removed together with the adhesive layer, and it becomes possible to remove the air bubbles between the release layer and the elastic layer generated during coating. However, when a large amount of adhesive is applied, the amount of the adhesive leaking out at the lower part becomes large, and the adhesive may move to the inner surface of the base material and cause inner surface contamination.

[0046] FIG. 5 is a schematic diagram showing uneven handling that occurs when the handling process is performed when the application of the adhesive is insufficient. When the application amount of the adhesive is insufficient, uneven application of the adhesive in a streak shape or an elliptical shape occurs by moving between the release layer and the elastic layer without being able to remove air. In the case of such unevenness, since the amount of the adhesive is small only in that part, an adhesion failure occurs, and the problem that the uneven part is transferred as a scratch to the image after fixing occurs.

[0047] Next, a comparison between this example and the conventional example is made.

[0048] Here, the coating amount per unit length required for air removal between the release layer and the elastic layer is defined as A (g / mm), the remaining amount of the adhesive per unit length required for adhesion is defined as B (g / mm), and the handling distance (distance from the handling start point) is defined as x (mm). Note that the relationship between the coating amount A and the remaining amount B is A > B.

[0049] FIG. 6 is a schematic diagram showing the adhesive coating and handling processes in the conventional example.

[0050] In this example, a 400-μm-thick addition reaction crosslinking type liquid silicone rubber was coated on a cylindrical substrate made of a nickel alloy with a thickness of 50 μm and a length of 400 mm of the fixing belt, and heat-cured at 200°C for 30 minutes to form a silicone rubber elastic layer 1b. After applying an adhesive to the formed cylinder, a PFA tube with a thickness of 50 μm was coated as a release layer, and a comparison was made of the states during the handling process. The experimental conditions are as follows.

[0051]

Table 1

[0052] Prior to this experiment, it was confirmed in advance that the coating amount A = 0.9 g / mm per unit length required for air removal and the remaining amount B = 0.6 g / mm of the adhesive per unit length required for adhesion.

[0053] FIG. 6(a) is a schematic diagram showing the case where, after applying more than the amount of adhesive required for air removal as shown in Conventional Example 1 (uniformly coated at 1.5 g / mm over the entire surface) and Conventional Example 2 (uniformly coated at 0.9 g / mm over the entire surface), the handling process was performed. In this case, air removal could be sufficiently performed, but finally, a larger amount of adhesive than the amount of adhesive required for adhesion continued to accumulate in the advancing direction of the ring, and finally, the excess adhesive was extruded and leaked, resulting in inner surface contamination.

[0054] In contrast, in FIG. 6(b), since only the amount of adhesive necessary for adhesion as shown in the conventional example 3 was applied, the adhesive did not accumulate in the advancing direction of the ring and there was no leakage of the adhesive. However, air removal could not be sufficiently performed, resulting in unevenness of the adhesive.

[0055] Thus, when applying the adhesive uniformly over the entire surface, it was impossible to achieve both air bubble removal and uniform adhesion.

[0056] FIG. 7 is a schematic diagram showing the adhesive application and handling process in this embodiment.

[0057] In this embodiment, when the amount of adhesive per unit area required for air discharge is A (g / mm), the amount of adhesive consumed per unit length due to adhesive handling is a (g / mm 2 ), and the distance from the upper end is x ( mm ), the adhesive was applied so that the adhesive application amount B (g / mm) in the longitudinal direction is B = A - ax. As a result, while the adhesive is consumed by the amount B (g / mm) necessary for adhesion when moving by a unit length, the amount of adhesive A (g / mm) necessary for air bubble removal can be maintained in front of the advancing direction of the handling ring, and finally, when reaching the handling end of the fixing member, adhesive leakage can be minimized and air bubble removal can be performed.

[0058] Accordingly, according to the present invention, in a fixing belt having a structure of a cylindrical substrate, a silicone rubber elastic layer, an adhesive layer, and a fluororesin release layer from the inner layer to the outer layer, by optimizing the method of applying the adhesive, adhesive leakage can be prevented, air removal is also possible, and both poor adhesion and adhesive leakage can be achieved.

Explanation of Reference Numerals

[0059] 1 Fixing belt 1a Fluororesin surface layer (fluororesin tube) 1b Silicone rubber elastic layer 1c Cylindrical substrate 2 Fixing heater 3 Thermistor 4 Film guide and heater holder 5 Fixing Belt Stay 6 Pressure Roller 7 Inlet Guide 8 Fixing Discharge Roller 9 A / D Converter 10 Control Circuit Section (CPU) 11 Heater Drive Circuit Section 12 Motor Drive Circuit Section 13 Apparatus Frame 14 Fixing Nip Section 21 Handling Ring 100 Fixing Device 101 Photosensitive Drum 102 Charging Device 103 Laser Beam 104 Developing Device 105 Intermediate Transfer Drum 106 Transfer Roller 107 Toner Cleaner 108 Toner Cleaner 109 Deflection Mirror 110 Laser Optical System T1 Primary Transfer Section T2 Secondary Transfer Section t Unfixed Toner Image P Recording Medium

Claims

1. In an endless fixing member composed of at least two layers, namely a surface layer and a base layer, from the outside, when the amount of adhesive per unit area required for air discharge is A (g / mm), the amount of adhesive consumed per unit length during adhesive handling is a (g / mm2), and the distance from the upper end is x (mm), the adhesive application amount B (g / mm) in the longitudinal direction is B = A - ax (inclined in the longitudinal direction) A method for manufacturing a fixing member, characterized by the above.

2. In an endless fixing member composed of at least two layers, namely a surface layer and a base layer, from the outside, when the amount of adhesive per unit area required for air discharge is A (g / mm), the amount of adhesive consumed per unit length during adhesive handling is a (g / mm2), and the distance from the upper end is x (mm), the adhesive application amount B (g / mm) in the longitudinal direction is B = A - ax (inclined in the longitudinal direction) A fixing member manufactured by the method for manufacturing a fixing member according to Claim 1, characterized by the above.

Images