JP2016180894A - Pressure member, fixing device, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure member that suppresses clogging of recording media, and a fixing device and an image forming apparatus that include the pressure member.SOLUTION: A pressure member comprises a pressure part that is in contact with an inner face of a tubular body arranged in contact with an outer face of a rotating member and presses the tubular body against the rotating member from the inner face of the tubular body; the pressure part is formed of a material including a crystalline resin; the quantity of heat at an exothermic peak A during an increase in temperature in the first cycle measured by differential scanning calorimetry is 15% or less relative to the quantity of heat at an exothermic peak B during an increase in temperature in the first cycle.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a pressure member, a fixing device, and an image forming apparatus.

  In an image forming apparatus such as a copying machine or a printer using an electrophotographic system, for example, a photosensitive member (photosensitive drum) formed in a drum shape is charged, and the photosensitive drum is controlled by light controlled based on image information. An electrostatic latent image is formed on the photosensitive drum by exposure, and the electrostatic latent image is converted into a visible image (toner image) with toner, and the toner image is transferred from the photosensitive drum to a recording medium such as paper. Thereafter, the toner image is fixed on the recording medium by a fixing device.

  Examples of the fixing device include a rotatable rotating member (for example, a heating roll), a tubular body (for example, a pressure belt such as an endless belt) disposed in contact with the rotating member, and an inner surface of the tubular body. A pressure member that presses the tubular body against the rotating member and forms a nip portion through which the recording medium passes between the rotating member and the tubular body, and allows the recording medium to pass through the nip portion. A fixing device that fixes a toner image on a recording medium (referred to as a “free belt nip method”) is known.

  As described above, in the fixing device configured to press the tubular body against the rotating member by the pressure member, when the sliding resistance (friction coefficient) between the tubular body and the pressure member increases, the tubular body rotates. It may be difficult to handle the rotating member, and a paper jam or the like of the recording medium may occur. For this reason, a technique for suppressing an increase in sliding resistance between the tubular body and the pressure member by supplying a lubricant or arranging a sliding sheet between the tubular body and the pressure member has been proposed. (For example, see Patent Documents 1 to 4).

  Incidentally, in recent years, in order to reduce the number of parts of the fixing device and reduce the cost, a fixing device in which a sliding sheet is not provided between the tubular body and the pressure member has been studied. Further, in such a fixing device, a technique for suppressing an increase in sliding resistance between the tubular body and the pressure member and suppressing occurrence of a paper jam in the recording medium has been studied.

JP 2003-195664 A JP 2004-109668 A JP 2006-91182 A JP 2006-91499 A

  An object of the present invention is to have a pressurizing part that contacts an inner surface of a tubular body disposed in contact with an outer surface of a rotating member and presses the tubular body against the rotating member from the inner surface of the tubular body, Is made of a material containing a crystalline resin, and the calorific value of the exothermic peak at the first temperature rise by differential scanning calorimetry is more than 15% with respect to the calorific value of the endothermic peak at the first cycle temperature rise. An object of the present invention is to provide a pressure member that suppresses occurrence of a paper jam in a recording medium, and a fixing device and an image forming apparatus including the pressure member.

  The invention according to claim 1 includes a pressurizing portion that contacts an inner surface of a tubular body disposed in contact with an outer surface of the rotating member and presses the tubular body against the rotating member from the inner surface of the tubular body. The pressing part is made of a material containing a crystalline resin, and the calorific value of the exothermic peak at the first temperature rise by differential scanning calorimetry is 15% of the heat quantity of the endothermic peak at the first temperature rise. The pressure member is as follows.

  The invention according to claim 2 is the pressure member according to claim 1, wherein the crystalline resin is polyethylene terephthalate.

  The invention according to claim 3 is in contact with the rotating member, the tubular body disposed in contact with the outer surface of the rotating member, and the inner surface of the tubular body, and the tubular body is transferred from the inner surface of the tubular body to the rotating member. And a pressure member having a pressure unit to be pressed, wherein the pressure member is a pressure member according to claim 1 or 2.

  According to a fourth aspect of the present invention, there is provided an image carrier, a charging unit that charges the surface of the image carrier, a latent image forming unit that forms an electrostatic latent image on the charged surface of the image carrier, and Developing means for developing an electrostatic latent image with a developer to form a toner image, transfer means for transferring the toner image to a recording medium, and fixing means for fixing the toner image to the recording medium, The image forming apparatus according to claim 3, wherein the fixing unit is a fixing device.

  According to the invention according to claim 1, the pressure member is in contact with the inner surface of the tubular body disposed in contact with the outer surface of the rotating member, and presses the tubular body against the rotating member from the inner surface of the tubular body, The pressurizing part is made of a material containing a crystalline resin, and the calorific value of the exothermic peak at the time of temperature rise in the first cycle by differential scanning calorimetry is relative to the heat quantity of the endothermic peak at the time of temperature rise in the first cycle. There is provided a pressure member in which occurrence of a paper jam of the recording medium is suppressed as compared with a pressure member exceeding 15%.

  According to the invention according to claim 2, the pressure member is in contact with the inner surface of the tubular body arranged in contact with the outer surface of the rotating member, and presses the tubular body against the rotating member from the inner surface of the tubular body, The pressurizing part contains a crystalline resin, and the calorific value of the exothermic peak at the first temperature rise by differential scanning calorimetry is more than 15% with respect to the calorific value of the endothermic peak at the first temperature rise. Compared with the pressurizing member, there is provided a pressurizing member in which the occurrence of a paper jam of the recording medium is suppressed.

  According to the invention according to claim 3, the pressure member is in contact with the inner surface of the tubular body disposed in contact with the outer surface of the rotating member, and presses the tubular body against the rotating member from the inner surface of the tubular body, The pressurizing part is made of a material containing a crystalline resin, and the calorific value of the exothermic peak at the time of temperature rise in the first cycle by differential scanning calorimetry is relative to the heat quantity of the endothermic peak at the time of temperature rise in the first cycle. A fixing device is provided in which the occurrence of a paper jam in the recording medium is suppressed as compared with a case where a pressure member exceeding 15% is used.

  According to the invention according to claim 4, the pressure member is in contact with the inner surface of the tubular body disposed in contact with the outer surface of the rotating member, and presses the tubular body from the inner surface of the tubular body to the rotating member, The pressurizing part is made of a material containing a crystalline resin, and the calorific value of the exothermic peak at the time of temperature rise in the first cycle by differential scanning calorimetry is relative to the heat quantity of the endothermic peak at the time of temperature rise in the first cycle. An image forming apparatus is provided in which occurrence of a paper jam in a recording medium is suppressed as compared with a case where a pressure member exceeding 15% is used.

1 is a schematic configuration diagram illustrating an example of a configuration of an image forming apparatus according to an embodiment of the present invention. 1 is a schematic configuration diagram illustrating an example of a configuration of a fixing device according to an exemplary embodiment of the present invention. It is a figure which shows the differential scanning calorific value curve (DSC curve) of the 1st cycle obtained by differential scanning calorimetry.

  Embodiments of the present invention will be described below. This embodiment is an example for carrying out the present invention, and the present invention is not limited to this embodiment.

  FIG. 1 is a schematic configuration diagram illustrating an example of a configuration of an image forming apparatus according to the present embodiment. The image forming apparatus 100 shown in FIG. 1 includes a plurality of image forming units 1Y, 1M, 1C, and 1K on which toner images of respective color components are formed by electrophotography, and the image forming units 1Y, 1M, 1C, and 1K. The primary transfer unit 10 that sequentially transfers (primary transfer) each color component toner image formed by the above process to the intermediate transfer belt 15 and the superimposed toner image transferred onto the intermediate transfer belt 15 are collectively transferred to a recording medium (recording paper) P. A secondary transfer unit 20 for (secondary transfer) and a fixing device 60 for fixing the secondary transferred image on the recording medium P are provided. Moreover, it has the control part 40 which controls operation | movement of each apparatus (each part).

  In this embodiment, each of the image forming units 1Y, 1M, 1C, and 1K includes a charger 12 that charges the photosensitive drum 11 around the photosensitive drum 11 that rotates in the direction of arrow A, and a photosensitive drum. A laser exposure unit 13 for writing an electrostatic latent image on the image 11 (in FIG. 1, the exposure beam is indicated by a symbol Bm), and each color component toner is accommodated so that the electrostatic latent image on the photosensitive drum 11 can be transferred with the toner. A developing device 14 for visualizing, a primary transfer roll 16 for transferring each color component toner image formed on the photosensitive drum 11 to the intermediate transfer belt 15 in the primary transfer unit 10, and residual toner on the photosensitive drum 11. An electrophotographic device such as a drum cleaner 17 is removed in order. These image forming units 1Y, 1M, 1C, and 1K are arranged substantially linearly in the order of yellow (Y), magenta (M), cyan (C), and black (K) from the upstream side of the intermediate transfer belt 15. Has been.

The intermediate transfer belt 15 which is an intermediate transfer member is constituted by a film endless belt (endless belt) in which an appropriate amount of an antistatic agent such as carbon black is contained in a resin such as polyimide or polyamide. The volume resistivity of the intermediate transfer belt 15 is formed to be, for example, 10 ⁶ Ωcm or more and 10 ¹⁴ Ωcm or less, and the thickness thereof is, for example, about 0.1 mm. The intermediate transfer belt 15 is circulated (rotated) by various rolls at a predetermined speed in the direction B shown in FIG. In the present embodiment, as various rolls, a drive roll 31 that is driven by a motor (not shown) having excellent constant speed and rotates the intermediate transfer belt 15 and extends along the arrangement direction of the photosensitive drums 11. Provided in the secondary transfer unit 20 are a support roll 32 that supports the intermediate transfer belt 15, a tension roll 33 that functions as a correction roll that applies tension to the intermediate transfer belt 15 and prevents meandering of the intermediate transfer belt 15, and the like. And a cleaning backup roll 34 provided in a cleaning unit that scrapes off residual toner on the intermediate transfer belt 15.

In the present embodiment, the primary transfer unit 10 includes a primary transfer roll 16 that is disposed to face the photosensitive drum 11 with the intermediate transfer belt 15 interposed therebetween. The primary transfer roll 16 includes, for example, a shaft (not shown) and a sponge layer (not shown) as an elastic layer fixed around the shaft. The shaft is, for example, a cylindrical bar made of a metal such as iron or SUS. The sponge layer is made of, for example, a blend rubber of acrylonitrile-butadiene rubber (NBR), styrene-butadiene rubber (SBR), and ethylene-propylene-diene rubber (EPDM) containing a conductive agent such as carbon black, and has a volume resistivity. Is a sponge-like cylindrical roll of 10 ⁷ Ωcm or more and 10 ⁹ Ωcm or less, for example. The primary transfer roll 16 is disposed in pressure contact with the photosensitive drum 11 with the intermediate transfer belt 15 interposed therebetween. Further, the primary transfer roll 16 is opposite to the toner charging polarity (negative polarity; the same applies hereinafter). A polarity voltage (primary transfer bias) is applied. As a result, the toner images on the respective photosensitive drums 11 are sequentially electrostatically attracted to the intermediate transfer belt 15 so as to form superimposed toner images on the intermediate transfer belt 15.

In the present embodiment, the secondary transfer unit 20 includes a secondary transfer roll 22 disposed on the toner image holding surface side of the intermediate transfer belt 15 and a backup roll 25. The backup roll 25 is composed of a tube of EPDM rubber and NBR blend rubber in which, for example, carbon is dispersed, and the inside is made of, for example, EPDM rubber. The surface resistivity is formed to be, for example, 10 ⁷ Ω / □ or more and 10 ¹⁰ Ω / □ or less, and the hardness is set to, for example, 70 ° (Asker C: manufactured by Kobunshi Keiki Co., Ltd.). Has been. The backup roll 25 is disposed on the back surface side of the intermediate transfer belt 15 to constitute a counter electrode of the secondary transfer roll 22, and a metal-made power supply roll 26 for applying a secondary transfer bias is disposed in contact therewith.

In the present embodiment, the secondary transfer roll 22 includes, for example, a shaft (not shown) and a sponge layer (not shown) as an elastic layer fixed around the shaft. The shaft is, for example, a cylindrical rod made of metal such as iron or SUS. The sponge layer is made of, for example, a blended rubber of NBR, SBR, and EPDM containing a conductive agent such as carbon black, and has a volume resistivity of 10 ⁷ Ωcm or more and 10 ⁹ Ωcm or less, such as a cylindrical shape such as a sponge. It is a roll. The secondary transfer roll 22 is disposed in pressure contact with the backup roll 25 with the intermediate transfer belt 15 interposed therebetween. Further, the secondary transfer roll 22 is grounded and a secondary transfer bias is formed between the secondary transfer roll 22 and the backup roll 25. Then, the toner image is secondarily transferred onto the recording medium P conveyed to the secondary transfer unit 20.

  Further, in the present embodiment, residual toner, paper dust, and the like on the intermediate transfer belt 15 after the secondary transfer are removed on the downstream side of the secondary transfer unit 20 of the intermediate transfer belt 15, and the surface of the intermediate transfer belt 15 is removed. An intermediate transfer belt cleaner 35 for cleaning the toner is detachably provided. Further, in the present embodiment, a reference sensor (home position sensor) 42 that generates a reference signal for taking an image forming timing in each of the image forming units 1Y, 1M, 1C, and 1K on the upstream side of the yellow image forming unit 1Y. Is arranged. Further, an image density sensor 43 for adjusting image quality is disposed on the downstream side of the black image forming unit 1K. The reference sensor 42 recognizes a mark provided on the back side of the intermediate transfer belt 15 and generates a reference signal. In response to an instruction from the control unit 40 based on the recognition of the reference signal, each image forming unit 1Y, 1M, 1C, and 1K are configured to start image formation.

  Furthermore, in the image forming apparatus 100 of the present embodiment, as a paper transport system, for example, a paper tray 50 that accommodates the recording medium P, and a pickup roll 51 that takes out and transports the recording medium P accumulated in the paper tray 50, The transport roll 52 that transports the recording medium P fed by the pickup roll 51, the transport chute 53 that feeds the recording medium P transported by the transport roll 52 to the secondary transfer unit 20, and the secondary transfer roll 22 A transport belt 55 that transports the recording medium P transported after the next transfer to the fixing device 60 and a fixing inlet guide 56 that guides the recording medium P to the fixing device 60 are provided.

  Next, a basic image forming process of the image forming apparatus 100 according to the present embodiment will be described.

  In the image forming apparatus 100 as shown in FIG. 1, image data output from an image reading apparatus (IIT) (not shown), a personal computer (PC) (not shown) or the like is received by an image processing apparatus (IPS) ( After the image processing is performed by the image forming unit 1Y, 1M, 1C, and 1K, an image forming operation is performed. Specifically, in the IPS, input reflectance data is subjected to predetermined image editing such as shading correction, position shift correction, brightness / color space conversion, gamma correction, frame deletion, color editing, moving editing, and the like. Image processing is performed. The image data that has been subjected to image processing is converted into color material gradation data of four colors Y, M, C, and K, and is output to the laser exposure unit 13.

  The laser exposure unit 13 irradiates, for example, an exposure beam Bm emitted from a semiconductor laser to the photosensitive drums 11 of the image forming units 1Y, 1M, 1C, and 1K according to the input color material gradation data. . In each of the photosensitive drums 11 of the image forming units 1Y, 1M, 1C, and 1K, the surface is charged by the charger 12, and then the surface is scanned and exposed by the laser exposure unit 13 to form an electrostatic latent image. The formed electrostatic latent images are developed as toner images of respective colors Y, M, C, and K by the respective image forming units 1Y, 1M, 1C, and 1K. The toner images formed on the photosensitive drums 11 of the image forming units 1Y, 1M, 1C, and 1K are transferred onto the intermediate transfer belt 15 in the primary transfer unit 10 where the photosensitive drums 11 and the intermediate transfer belt 15 are in contact with each other. Transcribed. More specifically, in the primary transfer unit 10, a voltage (primary transfer bias) having a polarity opposite to the charging polarity (negative polarity) of the toner is applied to the base material of the intermediate transfer belt 15 by the primary transfer roll 16. Primary transfer is performed by sequentially superposing the toner images on the surface of the intermediate transfer belt 15.

  After the toner images are sequentially primary transferred onto the surface of the intermediate transfer belt 15, the intermediate transfer belt 15 moves and the toner image is conveyed to the secondary transfer unit 20. When the toner image is conveyed to the secondary transfer unit 20, in the paper conveyance system, the pickup roll 51 rotates in accordance with the timing at which the toner image is conveyed to the secondary transfer unit 20, so Recording medium P, which is a sheet of paper, is supplied. The recording medium P supplied by the pickup roll 51 is transported by the transport roll 52 and reaches the secondary transfer unit 20 via the transport chute 53. Before reaching the secondary transfer unit 20, the recording medium P is temporarily stopped, and a registration roll (not shown) rotates in accordance with the movement timing of the intermediate transfer belt 15 on which the toner image is held. The position of the medium P and the position of the toner image are aligned.

  In the secondary transfer unit 20, the secondary transfer roll 22 is pressed against the backup roll 25 via the intermediate transfer belt 15. At this time, the recording medium P conveyed at the same timing is sandwiched between the intermediate transfer belt 15 and the secondary transfer roll 22. At this time, when a voltage (secondary transfer bias) having the same polarity as the toner charging polarity (negative polarity) is applied from the power supply roll 26, a transfer electric field is formed between the secondary transfer roll 22 and the backup roll 25. Is done. The unfixed toner image held on the intermediate transfer belt 15 is collectively electrostatically transferred onto the recording medium P by the secondary transfer unit 20 pressed by the secondary transfer roll 22 and the backup roll 25. The

  Thereafter, the recording medium P on which the toner image has been electrostatically transferred is transported as it is while being peeled off from the intermediate transfer belt 15 by the secondary transfer roll 22, and is provided downstream of the secondary transfer roll 22 in the paper transport direction. It is conveyed to the conveyor belt 55. On the conveyance belt 55, the recording medium P is conveyed to the fixing device 60 in accordance with the optimum conveyance speed in the fixing device 60. The unfixed toner image on the recording medium P conveyed to the fixing device 60 is fixed on the recording medium P by being subjected to a fixing process with heat and pressure by the fixing device 60, as will be described later. Then, the recording medium P on which the fixed image is formed is conveyed to a paper discharge placement unit provided in a discharge unit of the image forming apparatus.

  On the other hand, after the transfer to the recording medium P is completed, residual toner or the like remaining on the intermediate transfer belt 15 is conveyed to the cleaning unit as the intermediate transfer belt 15 rotates, and the cleaning backup roll 34 and the intermediate transfer belt cleaner. It is removed from the intermediate transfer belt 15 by 35.

  Next, the fixing device 60 used in the image forming apparatus 100 according to the present embodiment will be described with reference to the drawings. However, the present invention is not limited to the following embodiment.

  FIG. 2 is a side sectional view showing an example of the configuration of the fixing device used in the image forming apparatus according to the present embodiment. A fixing device 60 shown in FIG. 2 includes a fixing roll 61 as an example of a rotatable rotating member, a pressure belt 62 as an example of a tubular body disposed in contact with the fixing roll 61, and the inside of the pressure belt 62. The main part is comprised by the pressurization member 63 arrange | positioned in this.

  The fixing roll 61 shown in FIG. 2 is a cylindrical roll configured by laminating an elastic body layer 612 and a release layer 613 around a core (cylindrical cored bar) 611 made of metal or the like, and is rotatable. It is supported. Further, for example, a halogen heater 66 is provided inside the fixing roll 61 as a heating source. A temperature sensor 69 for controlling the temperature of the roll surface is provided around the fixing roll 61. For example, the controller 40 of the image forming apparatus 100 shown in FIG. 1 controls the lighting of the halogen heater 66 based on the temperature measurement value by the temperature sensor 69, and the surface temperature of the fixing roll 61 is set to a predetermined temperature (for example, 175 ° C.).

  The pressure belt 62 shown in FIG. 2 is rotatably supported by a pressure member 63 and a belt traveling guide 68 disposed inside the pressure belt 62. The pressure belt 62 comes into contact with the fixing roll 61 and rotates in the direction of the arrow according to the rotation of the fixing roll 61 (for example, a surface speed of 250 mm / second). The pressure belt 62 shown in FIG. 2 is preferably an endless belt without a seam formed in a cylindrical shape or the like so that a defect due to the seam does not occur in the output image.

  The pressure member 63 has a pressure pad 64 as an example of a pressure unit that contacts the inner surface of the pressure belt 62 and presses the pressure belt 62 toward the fixing roll 61 from the inner surface of the pressure belt 62. The pressure belt 64 is pressed against the fixing roll 61 by the pressure pad 64, and a nip portion N through which the recording medium P passes is formed between the fixing roll 61 and the pressure belt 62.

  The pressure pad 64 has a contact surface that contacts the inner surface of the pressure belt 62. The shape of the contact surface is not particularly limited, but from the viewpoint of smoothing the toner image surface to impart image gloss and improving the peelability of the recording medium P, as shown in FIG. The contact surface on the downstream side in the transport direction of the recording medium P (exit side of the nip portion N) is higher than the contact surface on the upstream side in the transport direction of the recording medium P (on the inlet side of the nip portion N). desirable. The pressure pad 64 includes, for example, a pre-nip member for securing a wide nip portion N on the inlet side (upstream side) of the nip portion N, and a fixing roll on the outlet side (downstream side) of the nip portion N. A peeling nip member for forming a down curl on the recording medium P by imparting distortion (dent) to the surface may be arranged.

  The pressure pad 64 is made of a material containing a crystalline resin. Further, in the pressure pad 64, the calorific value of the exothermic peak at the time of temperature rise in the first cycle by differential scanning calorimetry (DSC measurement) is 15% or less with respect to the calorific value of the endothermic peak at the time of temperature rise in the first cycle. . Here, the heat quantity of the endothermic peak is an absolute value. That is, when the heat value of the exothermic peak at the time of temperature rise in the first cycle is Q1 (J / g) and the heat amount of the endothermic peak at the time of temperature rise in the first cycle is Q2 (−J / g), Q1 ≦ | Q2 | × 0.15.

  The method of differential scanning calorimetry is as follows. 3 mg is scraped off as a sample from the pressure pad, and using a differential scanning calorimeter (manufactured by Shimadzu Corporation, DSC-60), the temperature is raised for the first cycle from 25 ° C. to 300 ° C. at a temperature rising rate of 10 ° C./min. It hold | maintains at 300 degreeC for 5 minutes, and it is carried out by lowering (cooling) to 25 degreeC as a temperature-fall rate -10 degreeC / min, and hold | maintaining at 25 degreeC for 5 minutes. Differential scanning calorimetry is performed on the initial pressure pad. The initial state refers to a state from when the pressure pad is manufactured to when the fixing device equipped with the pressure pad is operated for the first time.

  FIG. 3 is a diagram showing a differential scanning calorimetry curve (DSC curve) in the first cycle obtained by differential scanning calorimetry. The horizontal axis of the DSC curve shown in FIG. 3 represents the temperature rise time (min) of the first cycle, and the vertical axis represents the amount of heat (mW) generated during the temperature rise. In the DSC curve, the peak of the peak with respect to the baseline represents the exothermic peak, and the peak of the valley represents the endothermic peak. That is, peak A shown in FIG. 3 is an exothermic peak at the time of temperature increase in the first cycle (hereinafter, exothermic peak A), and peak B shown in FIG. 3 is an endothermic peak at the time of temperature increase in the first cycle (hereinafter, endothermic). Peak B). From the DSC curve, the peak area is determined by a method according to JIS K7122, and the peak area is calculated as the transition heat, whereby the calorific value (J / g) of each peak is determined. In the pressure pad 64 of the present embodiment, the amount of heat obtained from the area of the exothermic peak A at the time of temperature rise in the first cycle according to the differential scanning calorimetry curve is obtained from the area of the endothermic peak at the time of temperature rise in the first cycle. It becomes 15% or less with respect to the amount of heat (absolute value).

  Here, an exothermic peak is observed when the temperature rises in the first cycle. The pressure pad contains an amorphous resin component, and the amorphous resin component changes its state due to heat (amorphous resin). Crystallization, etc.). In addition, the fact that an endothermic peak is observed when the temperature rises in the first cycle indicates that the pressure pad contains a crystalline resin component, and the crystalline state of the crystalline resin component is dissolved and melted by heat (melting). It means) That is, the pressure of the present embodiment in which the calorific value of the exothermic peak at the first temperature rise by differential scanning calorimetry (DSC measurement) is 15% or less with respect to the calorific value of the endothermic peak at the first temperature rise. Compared with the pressure pad in which the heat quantity of the exothermic peak at the time of temperature rise in the first cycle exceeds 15% with respect to the heat quantity of the endothermic peak at the time of temperature rise in the first cycle, the pad 64 is made of amorphous resin. There are few, and it is thought that many crystalline resins exist.

  The pressure member 63 is preferably provided with a support member 65 that is attached to the back side of the pressure pad 64 as viewed from the nip portion N and supports the pressure pad 64 inside the pressure belt 62. Note that it is preferable that the pressure pad 64 and the support member 65 are integrally formed by providing a groove (not shown) on the back side of the pressure pad 64 and inserting one end of the support member 65 into the groove.

  The belt traveling guide 68 shown in FIG. 2 is attached to the support member 65 inside the pressure belt 62, and is configured such that the pressure belt 62 rotates around the outer peripheral surface of the belt traveling guide 68. The belt running guide 68 is preferably formed of a material having a small static friction coefficient in order to rub against the inner peripheral surface of the pressure belt 62. Further, it is desirable that the belt traveling guide 68 is formed of a material having a low thermal conductivity so that it is difficult to remove heat from the pressure belt 62.

  A lubricant application member 67 is disposed on the support member 65. The lubricant application member 67 is disposed so as to contact the inner peripheral surface of the pressure belt 62, and a lubricant such as amino-modified silicone oil is supplied to the inner peripheral surface of the pressure belt 62.

  The fixing device 60 shown in FIG. 2 preferably includes meandering prevention members (not shown) installed at both ends of the pressure belt 62. The meandering prevention members are arranged in a state of being spaced apart from each other at a constant distance so as to abut against the end face of the pressure belt 62 when meandering. The meandering prevention member suppresses the occurrence of meandering of the pressure belt 62, so-called belt walk. The meander-preventing member is formed of, for example, a heat-resistant resin such as PPS, PET, PBT, or LCP, or a material to which a filler for lowering durability or a friction coefficient is added.

  The operation of the fixing device 60 shown in FIG. 2 will be described.

  In the fixing device 60 shown in FIG. 2, the fixing roll 61 is connected to a drive motor (not shown) and rotates in the direction of the arrow, and the pressure belt 62 also rotates in the direction of the arrow following this rotation. The recording medium P on which the toner image has been electrostatically transferred in the secondary transfer unit 20 of the image forming apparatus shown in FIG. 1 is formed by the fixing roll 61 and the pressure belt 62 being pressed against each other by a conveying means (not shown). It is conveyed to the nip portion N. Then, when the recording medium P passes through the nip portion N, the toner image on the recording medium P is subjected to pressure acting on the nip portion N, heat supplied from the fixing roll 61, etc. The toner image is fixed on the recording medium P. The recording medium P after fixing passes through the nip portion N, is peeled off from the fixing roll 61, and is discharged from the fixing device 60. In this way, the fixing process is performed.

  By the way, in general, the fixing device is configured to press the pressure belt against the surface of the fixing roll with the pressure pad. Therefore, when the sliding resistance between the pressure belt and the pressure pad increases, the pressure belt For example, the recording medium P may be jammed at the nip portion N or the like. Usually, an increase in sliding resistance between the pressure belt and the pressure pad can be suppressed by supplying a lubricant between the pressure belt and the pressure pad. However, if the pressure pad is deformed due to heat from the fixing roll or heat due to sliding resistance with the pressure belt, especially if the pressure pad is deformed along the inner surface of the pressure belt, the pressure belt The space where the lubricant enters between the pressure pad and the space holding the lubricant decreases, and the sliding resistance between the pressure belt and the pressure pad may increase. Such deformation of the pressure pad is caused when the amorphous resin in the pressure pad is changed to a crystalline resin due to heat from the fixing roll or heat due to sliding resistance with the pressure belt. Conceivable.

  However, it is composed of a material containing a crystalline resin, and the calorific value of the exothermic peak at the first temperature rise by differential scanning calorimetry (DSC measurement) is larger than the calorific value of the endothermic peak at the first temperature rise. The pressure pad 64 of the present embodiment that is 15% or less is made of a material containing a crystalline resin, and the calorific value of the exothermic peak at the time of temperature rise in the first cycle by differential scanning calorimetry (DSC measurement) is 1 It is considered that the ratio of the crystalline resin in the pressure pad is large (the ratio of the amorphous resin is small) as compared with the pressure pad that exceeds 15% with respect to the heat amount of the endothermic peak at the time of temperature increase at the cycle. . For this reason, since the state change of the amorphous resin in the pressure pad 64 is small due to heat from the fixing roll 61 or heat due to sliding resistance with the pressure belt 62, deformation of the pressure pad 64 (particularly, the pressure belt 62). It is thought that deformation to a shape along the inner surface is suppressed. In the pressure pad 64 of the present embodiment, the calorific value of the exothermic peak at the time of temperature rise in the first cycle by differential scanning calorimetry (DSC measurement) is 15 with respect to the calorific value of the endothermic peak at the time of temperature rise in the first cycle. Compared with the pressure pad exceeding 100%, the deformation due to heat is small, so that the lubricant is easily supplied between the pressure belt 62 and the pressure pad 64, and the sliding resistance between the pressure belt 62 and the pressure pad 64 is reduced. It is considered that the increase is suppressed and the occurrence of paper jam of the recording medium P is suppressed.

  Hereinafter, members constituting the fixing device 60 will be described.

  The core 611 of the fixing roll 61 is formed of, for example, a metal or alloy having high thermal conductivity such as iron, aluminum (for example, A-5052 material), SUS, or copper, ceramics, or fiber reinforced metal (FRM).

  Examples of the material of the elastic layer 612 of the fixing roll 61 include elastic bodies such as rubber and elastomer whose rubber hardness is about 15 ° to 45 ° in terms of JIS-A hardness, and more specifically, silicone rubber, Examples thereof include fluororubber. Of these, silicone rubber is preferred from the viewpoints of low surface tension and excellent elasticity. Examples of such silicone rubber include RTV (room temperature vulcanization) silicone rubber, HTV (high temperature vulcanization) silicone rubber, and the like. Specifically, dimethyl silicone rubber (MQ) ), Methyl vinyl silicone rubber (VMQ), methyl phenyl silicone rubber (PMQ), fluorosilicone rubber (FVMQ), and the like. These may be used alone or in combination of two or more.

  The thickness of the elastic layer 612 is not particularly limited, but is, for example, 3 mm or less, and preferably in the range of 0.5 mm to 1.5 mm. There is no restriction | limiting in particular as a method of forming the elastic body layer 612 in the surface of the core 611, For example, a well-known coating method, a shaping | molding, etc. are employ | adopted.

  Examples of the material of the release layer 613 of the fixing roll 61 include fluoro rubber, silicone rubber, and fluoro resin. Of these materials, a fluororesin is preferable. The fluororesin is not particularly limited, and examples thereof include tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-perfluoromethyl vinyl ether copolymer (MFA), and tetrafluoroethylene-perfluoroethyl vinyl ether. Copolymer (EFA), polytetrafluoroethylene (PTFE), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), polyethylene / tetrafluoroethylene (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoride ethylene (PCTFE), vinyl fluoride (PVF) and the like. These may be used alone or in combination of two or more. For the purpose of imparting antistatic properties, the release layer 613 may contain, for example, conductive powder such as carbon black, graphite, and metal powder, and for the purpose of improving wear resistance. For example, powders of inorganic compounds such as titanium oxide, iron oxide, and aluminum oxide may be blended.

  The thickness of the release layer 613 is not particularly limited, but is, for example, in the range of 10 μm to 50 μm, and preferably in the range of 15 μm to 30 μm. There is no restriction | limiting in particular as a method of forming the mold release layer 613, For example, the method etc. which coat | cover the tube formed by the coating method mentioned above and extrusion molding, etc. are mentioned.

  There is no restriction | limiting in particular about the shape, a magnitude | size, etc. as the pressure belt 62, According to the objective, it selects suitably from conventionally well-known things. The structure of the pressure belt 62 may be a single layer structure or a multilayer structure.

  The material of the base layer of the pressure belt 62 is, for example, one or a mixture selected from thermosetting polyimide resin, thermoplastic polyimide resin, polyamide resin, polyamideimide resin, polybenzimidazole resin, stainless steel, Examples thereof include metals such as nickel and copper.

  Examples of the material of the covering layer of the pressure belt 62 include fluoro rubber, silicone rubber, fluoro resin, and the like. Examples of the silicone rubber include RTV (room temperature vulcanization) silicone rubber, HTV (high temperature vulcanization) silicone rubber, and the like. Specifically, dimethyl silicone rubber (MQ), methyl Examples thereof include vinyl silicone rubber (VMQ), methylphenyl silicone rubber (PMQ), and fluorosilicone rubber (FVMQ). Examples of the fluororesin include polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoromethyl vinyl ether copolymer (MFA), tetrafluoroethylene-perfluoroethyl vinyl ether copolymer (EFA), and tetrafluoroethylene-per Tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) such as fluoropropyl vinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer (FEP), ethylene-tetrafluoroethylene copolymer (ETFE), polyfluoride Vinylidene fluoride (PVDF), polychloroethylene trifluoride (PCTFE), polyvinyl fluoride (PVF), and the like. Among these, polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoromethyl vinyl ether copolymer (MFA), and tetrafluoroethylene-perfluoroethyl vinyl ether copolymer are particularly preferred from the standpoints of heat resistance and mechanical properties. A tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) such as a combination (EFA) is preferred. These may be used alone or in combination of two or more.

  The thickness of the pressure belt 62 is set to, for example, 45 μm to 130 μm, preferably 55 μm to 100 μm. When the thickness of the pressure belt 62 is less than 45 μm, the strength of the pressure belt 62 may be reduced as compared with the case where the thickness is 45 μm or more. When the thickness of the pressure belt 62 exceeds 130 μm, the heat capacity of the pressure belt 62 increases as compared with the case where the pressure belt 62 is 130 μm or less. As a result, the power consumption for securing the supply heat amount necessary for fixing increases. There is a case. The “thickness” of the pressure belt 62 means an average thickness in the width direction. The circumferential length and width of the pressure belt 62 are not particularly limited.

  The pressure pad 64 of the present embodiment is made of a material containing a crystalline resin. Examples of the crystalline resin include crystalline resins such as polyethylene, polypropylene, polyamide, polyacetal, polyethylene terephthalate, polybutylene terephthalate, methylpentene, polyphenylene sulfide, polyether ether ketone, polytetrafluoroethylene, and nylon. Among these, polyethylene terephthalate is preferable from the viewpoints of slidability, heat resistance and molding processability. Here, crystallinity means that in differential scanning calorimetry, it has a clear endothermic peak, not a stepwise change in endothermic amount, and specifically, when measured at a heating rate of 10 ° C./min. It means that the half width of the endothermic peak is within 10 ° C. As a material containing a crystalline resin, an additive such as a filler may be included in addition to the crystalline resin. Examples of the additive include glass fiber, metal fiber, metal flake, and carbon fiber.

  In the pressure pad 64 of the present embodiment, the calorific value of the exothermic peak at the time of temperature rise in the first cycle by differential scanning calorimetry (DSC measurement) is 15% or less with respect to the amount of heat at the endothermic peak at the time of temperature rise in the first cycle. If it is, it will not restrict | limit in particular, The calorie | heat amount of the exothermic peak at the time of temperature rising of the 1st cycle shall be 2% or more and 15% or less with respect to the calorie | heat amount of the endothermic peak at the time of temperature rising of the 1st cycle Is preferably 2% or more and 8% or less. A pressure pad with an exothermic peak at the time of temperature rise in the first cycle of 15% or less of the heat quantity at the endothermic peak at the time of temperature rise in the first cycle is more amorphous than a pressure pad exceeding 15%. It is thought that there is little resin and the amount of deformation of the pressure pad due to heat is small. As a result, it is considered that the paper jam of the recording medium P is suppressed as described above. In addition, the heat pad of the exothermic peak at the time of temperature rise in the first cycle is less than 2% with respect to the heat amount of the endothermic peak at the time of temperature rise in the first cycle, compared with a pressure pad of 2% or more, It is considered that the slidability deteriorates.

  In the pressure pad 64 of the present embodiment, although depending on the material used, it is preferable that the calorific value of the exothermic peak at the time of temperature rise in the first cycle by differential scanning calorimetry (DSC measurement) is 3.0 J / g or less. More preferably, it is 0.5 J / g or more and 2.5 J / g or less. When the calorific value of the exothermic peak at the time of temperature rise in the first cycle by differential scanning calorimetry (DSC measurement) exceeds 3 J / g, the amount of deformation of the pressure pad due to heat increases compared to the case of 3 J / g or less. There is a case.

  Further, the endothermic peak at the time of temperature rise in the first cycle by differential scanning calorimetry (DSC measurement) is preferably observed at 115 ° C. or higher, and more preferably observed at 117 ° C. or higher. When the endothermic peak at the first cycle temperature rise is observed below 115 ° C., the heat pressure during the fixing process is higher than when the endothermic peak at the first cycle temperature rise is observed at 115 ° C. or higher. The amount of deformation of the pad may increase.

  The pressure pad 64 of the present embodiment is manufactured by, for example, heat-melt molding a raw material resin or the like. Although the temperature at the time of shaping | molding is suitably set with the raw material to be used, it is preferable to set it as 240 degreeC or more and 290 degrees C or less, for example. If the temperature at the time of molding is less than 240 ° C, molding defects may occur in the pressure pad 64 as compared to the case of 240 ° C or more. If the temperature exceeds 290 ° C, it is compared with the case of 290 ° C or less. The strength of the pressure pad 64 may decrease.

  In addition, for example, by adjusting the cooling rate of the pressure pad after heat-melt molding, the calorific value of the exothermic peak at the time of temperature rise in the first cycle by differential scanning calorimetry (DSC measurement) is increased at the time of temperature rise in the first cycle. A pressure pad of 15% or less with respect to the heat quantity of the endothermic peak is obtained. The cooling rate of the pressure pad after heat-melt molding depends on the raw materials used, but is preferably in the range of 100 ° C./min to 300 ° C./min, for example 150 ° C./min to 250 ° C./min. The following range is more preferable. When the cooling rate of the pressure pad after heat-melt molding exceeds 300 ° C./min, more amorphous resin remains in the pressure pad than in the case of 300 ° C./min or less, and the temperature rise in the first cycle The amount of heat at the exothermic peak at the time may be more than 15% with respect to the amount of heat at the endothermic peak at the time of temperature increase in the first cycle. If the cooling rate of the pressure pad after heat-melt molding is less than 100 ° C./min, the slidability may be deteriorated. In addition, for example, by giving a thermal history that repeats cooling and heating a plurality of times to the pressure pad after heat-melt molding, the exothermic peak at the time of temperature rise in the first cycle by differential scanning calorimetry (DSC measurement), etc. A pressure pad is obtained in which the amount of heat becomes 15% or less with respect to the amount of heat of the endothermic peak at the time of temperature rise in the first cycle.

  Although the thickness of the pressure pad 64 of this embodiment is not specifically limited, For example, the range of 0.5 mm or more and 10 mm or less is preferable, and the range of 1.5 mm or more and 5 mm or less is more preferable. When the thickness of the pressure pad 64 is less than 0.5 mm, the durability and the heat-resistant material strength may be insufficient and may be deformed, and the material cost may be excessive.

  The pressure pad 64 of this embodiment is supported by the support member 65 so as to press the fixing roll 61 with a load of, for example, 30 kgf by a spring, an elastic body, or the like.

  The support member 65 is made of, for example, a resin such as PPS, polyimide, polyamide, a glass fiber-containing liquid crystal polymer or polyester; a metal such as iron, aluminum, or SUS; a metal oxide.

  The pressing member 63 may have an elastic layer or the like disposed between the pressure pad 64 and the support member 65. Examples of the material of the elastic layer include elastic bodies such as rubber and elastomer whose rubber hardness is about 15 ° to 45 ° in terms of JIS-A hardness, and more specifically, silicone rubber, fluorine rubber, and the like. Used.

  So far, the pressurizing unit has been described using the pressure pad 64 as an example, but the pressurizing unit is not limited to the pressure pad 64 shown in FIG. 2, and is a tubular body arranged in contact with the outer surface of the rotating body. Any shape structure may be used as long as it contacts the inner surface and presses the tubular body against the rotating body from the inner surface of the tubular body.

  The lubricant is preferably one that maintains the lubricity with the inner peripheral surface of the pressure belt 62 even when used for a long time under a fixing temperature environment, and further, durability against long-term use under a fixing temperature environment, What is excellent in heat resistance and volatility is more preferable. An index of lubricity is kinematic viscosity. For example, a lubricant having a kinematic viscosity of 100 cSt or more and 300 cSt or less is preferable from the viewpoint of sliding resistance. The kinematic viscosity of the lubricant is measured by a capillary viscometer method (ISO 3104).

  As the lubricant, for example, liquid oil such as silicone oil and fluorine oil, synthetic lubricating oil grease in which a solid substance and a liquid are mixed, and combinations thereof are used. Examples of the silicone oil include dimethyl silicone oil, dimethyl silicone oil with an organic metal salt added, hindered amine added dimethyl silicone oil, an organic metal salt and a hindered amine added dimethyl silicone oil, methyl phenyl silicone oil, amino-modified silicone oil, and organic metal salt added amino. Examples include modified silicone oil, hindered amine-added amino-modified silicone oil, carboxy-modified silicone oil, silanol-modified silicone oil, and sulfonic acid-modified silicone oil. Examples of the fluorine oil include perfluoropolyether oil and modified perfluoropolyether oil.

  As the lubricant, silicone oil is preferable from the viewpoint of maintenance of lubricity, heat resistance, volatility, and the like. Furthermore, amino-modified silicone oil is more preferable from the viewpoint of wettability, and methylphenyl silicone oil is more preferable when heat resistance is required. From the viewpoint of improving heat resistance, an antioxidant may be added to the lubricant in the silicone oil.

  In the fixing device 60 illustrated in FIG. 2, the heating roller is illustrated as the rotating member, and the pressure belt disposed on the side that does not contact the toner image on the recording medium is illustrated as the tubular body. The tubular body is not limited to these, and the rotating member may be a pressure roll, and the tubular body may be used as a fixing belt disposed on the side in contact with the toner image on the recording medium.

  Hereinafter, although an example and a comparative example are given and the present invention is explained more concretely in detail, the present invention is not limited to the following examples.

Example 1
In the fixing roll, an outer peripheral surface of a cylindrical aluminum core is coated with a silicone rubber having a thickness of 0.65 mm as an elastic layer, and a fluororesin is coated as a release layer on the surface of the elastic layer. It is a roll having a diameter of 22 mm. The pressure belt is made of polyimide resin as a base material (thickness 55 μm, outer diameter 20 mm), and the outer peripheral surface of the base material is coated with a fluororesin layer as a release layer with a thickness of 25 μm. Inside the fixing roll, a 720 w halogen lamp was disposed as a heating source.

  As a material constituting the pressure pad, polyethylene terephthalate (PET-FC02) manufactured by DuPont was used, and the pressure pad was produced by injection molding into a mold having a resin melting temperature of 270 ° C. and a surface temperature of 80 ° C.

  Differential scanning calorimetry was performed on the pressure pad of Example 1 under the conditions described above. As a result, the heat value of the exothermic peak at the time of temperature rise in the first cycle is 2.4 (J / g), and the heat amount of the endothermic peak at the time of temperature rise in the first cycle is 16.8 (−J / g). Met. That is, the heat value of the exothermic peak at the time of temperature increase in the first cycle was 14% with respect to the heat amount of the endothermic peak at the time of temperature increase in the first cycle. Moreover, since the half value width of the endothermic peak was within 10 ° C., it can be said that the pressure pad of Example 1 is composed of a material containing a crystalline resin of polyethylene terephthalate.

  In the image forming apparatus DocuPrint CM200 manufactured by Fuji Xerox Co., which is equipped with the fixing device equipped with the pressure pad of Example 1, the load between the pressure belt and the heating roll (that is, the load of the nip portion N) is set to 15 kg. The fixing temperature was controlled at 155 ° C. (measured with a temperature sensor placed in the vicinity of the pressing portion on the plain paper entrance side), and A4 paper (P paper made by Fuji Xerox Co., Ltd.) was fed at a speed of 88 mm / sec. Thousand sheets were passed and tested for the presence of paper jams. Further, the deformation of the pressure pad after the test was visually observed. As a result, no paper jam occurred and the pressure pad was hardly deformed.

(Example 2)
As a material constituting the pressure pad, polyphenylene sulfide (PPS-A504X90) manufactured by Toray Industries, Inc. was used, and a pressure pad was produced by injection molding into a mold having a resin melting temperature of 330 ° C. and a surface temperature of 85 ° C.

  Differential scanning calorimetry was performed on the pressure pad of Example 2 under the conditions described above. As a result, the calorific value of the exothermic peak at the time of temperature rise in the first cycle is 2.2 (J / g), and the calorific value of the endothermic peak at the time of temperature rise in the first cycle is 22.3 (−J / g). Met. That is, the heat value of the exothermic peak at the time of temperature increase in the first cycle was 10% with respect to the heat amount of the endothermic peak at the time of temperature increase in the first cycle. Further, since the half-value width of the endothermic peak was within 10 ° C., it can be said that the pressure pad of Example 2 was made of a material containing polyphenylene sulfide crystalline resin.

  The test was performed under the same conditions as in Example 1 except that the pressure pad of Example 2 was used. As a result, no paper jam occurred and the pressure pad was hardly deformed.

Example 3
As a material constituting the pressure pad, polybutylene terephthalate (DURANEX 201NF) manufactured by Polyplastics was used, and the pressure pad was produced by injection molding into a mold having a resin melting temperature of 250 ° C. and a surface temperature of 75 ° C. .

  Differential scanning calorimetry was performed on the pressure pad of Example 3 under the conditions described above. As a result, the calorific value of the exothermic peak at the time of temperature rise in the first cycle is 4.3 (J / g), and the calorific value of the endothermic peak at the time of temperature rise in the first cycle is 39.6 (−J / g). Met. That is, the heat value of the exothermic peak at the time of temperature increase in the first cycle was 11% with respect to the heat amount of the endothermic peak at the time of temperature increase in the first cycle. Moreover, since the half value width of the endothermic peak was within 10 ° C., it can be said that the pressure pad of Example 3 is made of a material containing a polybutylene terephthalate crystalline resin.

  The test was performed under the same conditions as in Example 1 except that the pressure pad of Example 3 was used. As a result, no paper jam occurred and the pressure pad was hardly deformed.

Example 4
As a material constituting the pressure pad, polyethylene terephthalate (PET-FC02) manufactured by DuPont was used, injection-molded into a mold having a resin melting temperature of 270 ° C. and a surface temperature of 70 ° C., and then placed in an oven at 115 ° C. A pressure pad was prepared by adding a thermal history after standing for a minute.

  Differential scanning calorimetry was performed on the pressure pad of Example 4 under the conditions described above. As a result, the calorific value of the exothermic peak when raising the temperature in the first cycle is 0.5 (J / g), and the calorific value of the endothermic peak when raising the temperature in the first cycle is 25.3 (-J / g). Met. That is, the heat value of the exothermic peak at the time of temperature increase in the first cycle was 2% with respect to the heat amount of the endothermic peak at the time of temperature increase in the first cycle. Moreover, since the half value width of the endothermic peak was within 10 ° C., it can be said that the pressure pad of Example 4 is composed of a material containing a crystalline resin of polyethylene terephthalate.

  The test was performed under the same conditions as in Example 1 except that the pressure pad of Example 4 was used. As a result, no paper jam occurred and no deformation of the pressure pad was confirmed.

(Example 5)
As a material constituting the pressure pad, polyethylene terephthalate (PET-FC02) manufactured by DuPont was used, injection molded into a mold having a resin melting temperature of 270 ° C. and a surface temperature of 70 ° C., and then placed in a 100 ° C. oven for 10 minutes. A pressure pad was prepared by adding a thermal history of standing.

  Differential scanning calorimetry was performed on the pressure pad of Example 5 under the conditions described above. As a result, the calorific value of the exothermic peak at the time of temperature rise in the first cycle is 1.4 (J / g), and the calorific value of the endothermic peak at the time of temperature rise in the first cycle is 17.5 (−J / g). Met. That is, the heat value of the exothermic peak at the time of temperature increase in the first cycle was 8% with respect to the heat amount of the endothermic peak at the time of temperature increase in the first cycle. Moreover, since the half value width of the endothermic peak was within 10 ° C., it can be said that the pressure pad of Example 5 was made of a material containing a crystalline resin of polyethylene terephthalate.

  The test was performed under the same conditions as in Example 1 except that the pressure pad of Example 5 was used. As a result, no paper jam occurred and no deformation of the pressure pad was confirmed.

(Comparative Example 1)
As a material constituting the pressure pad, polyethylene terephthalate (PET-FC02) manufactured by DuPont was used, and the pressure pad was produced by injection molding into a mold having a resin melting temperature of 270 ° C. and a surface temperature of 40 ° C.

  Differential scanning calorimetry was performed on the pressure pad of Comparative Example 1 under the conditions described above. As a result, the calorific value of the exothermic peak at the time of temperature rise in the first cycle is 9.0 (J / g), and the calorific value of the endothermic peak at the time of temperature rise in the first cycle is 26.2 (−J / g). Met. That is, the heat value of the exothermic peak at the time of temperature increase in the first cycle was 34% with respect to the heat amount of the endothermic peak at the time of temperature increase in the first cycle. Moreover, since the half width of the endothermic peak was within 10 ° C., it can be said that the pressure pad of Comparative Example 1 is composed of a material containing a polyethylene terephthalate crystalline resin.

  The test was performed under the same conditions as in Example 1 except that the pressure pad of Comparative Example 1 was used. As a result, a paper jam occurred and deformation of the pressure pad was confirmed.

(Comparative Example 2)
As a material constituting the pressure pad, polyethylene terephthalate (PET-FC02) manufactured by DuPont was used, and the pressure pad was produced by injection molding into a mold having a resin melting temperature of 270 ° C. and a surface temperature of 70 ° C.

  The differential scanning calorimetry was performed on the pressure pad of Comparative Example 2 under the conditions described above. As a result, the heat value of the exothermic peak at the time of temperature increase in the first cycle is 3.2 (J / g), and the heat amount of the endothermic peak at the time of temperature increase in the first cycle is 16.8 (−J / g). Met. That is, the heat value of the exothermic peak at the time of temperature increase in the first cycle was 19% with respect to the heat amount of the endothermic peak at the time of temperature increase in the first cycle. Moreover, since the half width of the endothermic peak was within 10 ° C., it can be said that the pressure pad of Comparative Example 2 is composed of a material containing a polyethylene terephthalate crystalline resin.

  The test was performed under the same conditions as in Example 1 except that the pressure pad of Comparative Example 2 was used. As a result, a paper jam occurred and deformation of the pressure pad was confirmed.

(Comparative Example 3)
As a material constituting the pressure pad, polyethylene terephthalate (PET-FC02) manufactured by DuPont was used, and the pressure pad was produced by injection molding into a mold having a resin melting temperature of 270 ° C. and a surface temperature of 75 ° C.

  Differential scanning calorimetry was performed on the pressure pad of Comparative Example 3 under the conditions described above. As a result, the calorific value of the exothermic peak at the time of temperature rise in the first cycle is 3.3 (J / g), and the calorific value of the endothermic peak at the time of temperature rise in the first cycle is 20.2 (−J / g). Met. That is, the heat value of the exothermic peak at the time of temperature increase in the first cycle was 16% with respect to the heat amount of the endothermic peak at the time of temperature increase in the first cycle. Moreover, since the half value width of the endothermic peak was within 10 ° C., it can be said that the pressure pad of Comparative Example 3 is composed of a material containing a polyethylene terephthalate crystalline resin.

  The test was performed under the same conditions as in Example 1 except that the pressure pad of Comparative Example 3 was used. As a result, a paper jam occurred and deformation of the pressure pad was confirmed.

  Table 1 summarizes the calorific value of the exothermic peak, the calorific value of the endothermic peak, the presence or absence of occurrence of paper jam, and the deformation of the pressure pad in Examples 1 to 5 and Comparative Examples 1 to 3.

  A pressure pad including a crystalline resin and having an exothermic peak calorific value at the time of temperature rise in the first cycle by differential scanning calorimetry that is 15% or less of the heat value of the endothermic peak at the time of temperature rise in the first cycle. Examples 1 to 5 using a pressure member include a crystalline resin, and the calorific value of the exothermic peak at the time of temperature rise in the first cycle by differential scanning calorimetry is the calorific value of the endothermic peak at the time of temperature rise in the first cycle. On the other hand, the occurrence of a paper jam in the recording medium was suppressed as compared with Comparative Examples 1 to 3 using a pressure member having a pressure pad exceeding 15%. In particular, in Examples 1 to 5, the calorific value of the exothermic peak at the time of temperature rise in the first cycle by differential scanning calorimetry is 2% or more and 8% with respect to the amount of heat of the endothermic peak at the time of temperature rise in the first cycle. It can be said that Examples 4 to 5 using a pressure member having a pressure pad as described below are preferable in that deformation of the pressure pad is further suppressed.

  1Y, 1M, 1C, 1K Image forming unit, 10 Primary transfer unit, 11 Photosensitive drum, 12 Charger, 13 Laser exposure unit, 14 Developer, 15 Intermediate transfer belt, 16 Primary transfer roll, 17 Drum cleaner, 20 2 Next transfer section, 22 Secondary transfer roll, 25 Backup roll, 26 Feed roll, 31 Drive roll, 32 Support roll, 33 Tension roll, 34 Cleaning backup roll, 35 Intermediate transfer belt cleaner, 40 Control section, 42 Reference sensor, 43 Image density sensor, 50 paper tray, 51 pickup roll, 52 transport roll, 53 transport chute, 55 transport belt, 56 fixing inlet guide, 60 fixing device, 61 fixing roll, 62 pressure belt, 63 pressure member, 64 pressure pad 65 Support member 66 Halogen heater, 67 Lubricant application member, 68 belt running guide, 69 temperature sensor, 100 image forming apparatus, 611 core, 612 elastic body layer, 613 release layer.

Claims (4)

A pressure portion that contacts an inner surface of a tubular body disposed in contact with an outer surface of the rotating body and presses the tubular body from the inner surface of the tubular body to the rotating body;
The pressurizing part includes a crystalline resin, and the calorific value of the exothermic peak at the first temperature rise by differential scanning calorimetry is 15% or less with respect to the calorific value of the endothermic peak at the first temperature rise. There is a pressure member.   The pressure member according to claim 1, wherein the crystalline resin is polyethylene terephthalate. Pressurization having a rotating body, a tubular body arranged in contact with the outer surface of the rotating body, and a pressurizing unit that contacts the inner surface of the tubular body and presses the tubular body from the inner surface of the tubular body to the rotating body A member, and
The fixing device according to claim 1, wherein the pressure member is the pressure member according to claim 1. An image carrier, a charging unit for charging the surface of the image carrier, a latent image forming unit for forming an electrostatic latent image on the charged surface of the image carrier, and the electrostatic latent image by a developer. Development means for developing and forming a toner image; transfer means for transferring the toner image to a recording medium; and fixing means for fixing the toner image to the recording medium;
The image forming apparatus according to claim 3, wherein the fixing unit is the fixing device according to claim 3.

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