JP2007047379A - Separation plate, fixing device with separation plate, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a separation plate which can prevent a drop of water from being grown on the separation plate owing to dew condensation and make a fixing device and an image forming apparatus have high picture quality, at a low cost. <P>SOLUTION: The separation plate 1 is configured to separate transfer paper S, discharged through a nip part N formed of a fixing member 2 and a pressure member 3 pressed against the fixing member 2, from the fixing member 2. The separation plate 1 has many microgroove portions 5, stopping the drop of water from being grown, on its surface 1a where the transfer paper P passes on. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a separation plate that separates transfer paper from a fixing member, a fixing device including the separation plate, and an image forming apparatus.

  As electrophotographic image forming apparatuses, copying machines, facsimiles, printers, and the like are known. In a conventional printer, a photosensitive member is charged using a charging unit, and exposed to an exposing unit such as a laser beam to form an electrostatic latent image on the photosensitive member. The electrostatic latent image is developed with toner using a developing unit. And developing it to visualize it as a toner image. Thereafter, the toner image is transferred onto a transfer sheet by a transfer unit, and the transferred toner image is fixed on the transfer sheet via a fixing device to form an image.

  The fixing device includes a hollow cylindrical fixing roller having a heat source therein as a fixing member, and a pressure roller as a pressure member pressed against the fixing roller. Then, the transfer paper on which the toner image has been transferred is passed through the nip formed between the fixing roller and the pressure roller, so that the toner adhering to the transfer paper is added while being melted by the heat of the fixing roller. It is fixed on the transfer paper by pressure.

  Further, in recent years, a fixing device accompanying colorization includes, as a fixing member, an endless fixing belt wound between a heating roller having a heat source therein and a fixing roller, and a fixing roller via the fixing belt. And a pressure roller as a pressure member that is disposed opposite to each other and has a heat source therein. Then, the toner is fixed on the transfer paper by passing the transfer paper on which the toner image is formed in the nip portion between the fixing belt and the pressure roller.

  In any of the above fixing devices, since the toner is melted and fixed on the transfer paper by the heating means, the transfer paper may be wound around the surface of the fixing roller or the fixing belt as a fixing member due to the viscosity of the melted toner. There is.

  Therefore, in the conventional fixing device, at least three separation claws are scattered in the longitudinal direction of the fixing roller at the exit portion of the nip portion, and the transfer paper is separated from the fixing member by the separation claws. The separation claw has a problem that the transfer paper cannot be sufficiently separated.

  For this reason, a separation plate for separating the transfer paper from the fixing member is provided at the exit portion of the nip portion of the fixing device, and the transfer paper passes from the fixing member by the leading edge of the transfer paper passing through the nip portion hitting the separation plate. A technique has been proposed in which the transfer paper is forcibly separated to prevent the transfer paper from being wound around a fixing member (Patent Document 1).

  However, in the fixing device, since the toner is melted and fixed by the heating means, the transfer paper is heated when the transfer paper passes through the nip portion, and the transfer paper after passing through the nip portion. The moisture contained in the transfer paper is released as water vapor. If the separation plate of the fixing device is not sufficiently warmed, such as immediately after the printer has started up from the standby state, the water vapor evaporated from the transfer paper touches the surface of the separation plate located at the exit portion of the nip, causing condensation. There is a problem that water droplets due to the condensation adhere to the transfer paper after fixing and image defects occur.

  Therefore, in order to prevent image defects due to the water droplets, a rib is provided on the guide surface of the separation plate that contacts the surface of the transfer paper separated from the fixing member to prevent the transfer paper from coming into surface contact with the separation plate. Has been proposed to make it difficult to adhere to the transfer paper (Patent Document 2), but with such a structure, there is a problem that it is not possible to completely prevent the water droplets on the separation plate from adhering to the transfer paper. .

In addition, a separation plate in which the height of the upstream edge is lower than the height of the downstream edge with respect to the transfer paper discharge direction is provided, and a hook-shaped member is provided to face the upstream edge of the separation plate, It has been proposed that water droplets formed on the separator plate be poured into the bowl-shaped member along the slope of the separator plate (Patent Document 3). However, such a technique complicates the structure and increases the cost of the fixing device. As a result, the cost of the entire printer increases.
JP 2003-122175 A JP 2004-205750 A JP 2003-215967 A

  The present invention aims to solve such problems, and has as its first object to provide a separation plate that can prevent the growth of water droplets due to condensation at a low cost, and can achieve high image quality. A second object is to provide a fixing device and an image forming apparatus at low cost.

  In order to achieve the above object, the separation plate according to claim 1 is configured such that the transfer paper discharged through a nip portion composed of a fixing member and a pressure member pressed against the fixing member is the fixing plate. The separation plate separated from the member is characterized in that the separation plate has a large number of minute grooves on the surface through which the transfer paper passes to prevent the growth of water droplets.

  According to a second aspect of the present invention, the separation plate according to the first aspect is characterized in that the minute groove portion is provided in the sheet passing direction of the transfer paper.

  The separation plate according to claim 3 is characterized in that, in the separation plate according to claim 2, the minute groove portion has a groove width formed so as to expand toward the sheet passing direction of the transfer paper. .

  The separation plate according to claim 4 is the separation plate according to claim 2, wherein the minute groove portion is provided in a direction intersecting with the minute groove portion provided toward the sheet passing direction of the transfer paper. It is a feature.

  The separation plate according to claim 5 is the separation plate according to claim 1, wherein the transfer sheet of the separation plate passes through a release layer composed of a mixed material of fluororesin and polyimide resin or polyamideimide resin. It is provided on the side surface.

The separation plate according to claim 6 is the separation plate according to claim 5, wherein the separation plate is a front end portion that separates the transfer paper from the fixing member and is in contact with the fixing member. It has a release layer composed of a mixed material of resin and polyimide resin or polyamideimide resin.

  The separation plate according to claim 7 is the separation plate according to claim 5 or 6, wherein the release layer provided in the minute groove portion is provided on a surface on the side through which the transfer paper passes except for the minute groove portion. It is characterized in that the content of the fluororesin is less than that of the obtained release layer.

  According to an eighth aspect of the present invention, in the fixing device according to the first aspect, the separation plate according to any one of the first to seventh aspects is provided in the vicinity of a nip portion that includes a fixing member and a pressure member that presses the fixing member. It is characterized by being provided.

  An image forming apparatus according to a ninth aspect includes the fixing device according to the eighth aspect.

  The separation plate according to claim 1 is configured such that the transfer paper discharged through a nip portion constituted by a fixing member and a pressure member pressed against the fixing member is separated from the fixing member. In the separation plate, since the separation plate has a large number of minute groove portions on the surface on the side through which the transfer paper passes, water vapor is prevented from being transferred by the large number of minute groove portions. It is possible to suppress the action of dew condensation on the surface on the side through which the water passes, and to suppress the action of a plurality of water droplets to be combined into one, thereby preventing the growth of water drops due to condensation.

  In addition, since the growth of water droplets due to condensation can be prevented simply by providing a minute groove on the surface of the separation plate on the side through which the transfer paper passes, the structure of the separation plate is simplified. Can be offered at.

  The separation plate according to claim 2, wherein the minute groove portion is provided toward the sheet passing direction of the transfer paper, so that warm air heated by a heating roller or the like near the exit of the nip portion is The separation plate flows from the leading end side to the base end side along the line, so that the separation plate immediately after the start-up of the printer can be warmed up immediately, thus preventing the occurrence of condensation on the separation plate. be able to.

  Since the separation plate according to claim 3 has a groove width formed so that the minute groove portion expands in the sheet passing direction of the transfer paper, the surface area of the concave portion of the minute groove portion is increased, For this reason, it is possible to further suppress the action of water vapor on the surface of the separator plate on the side where the transfer paper passes, thereby further preventing the growth of water droplets due to condensation.

  In the separation plate according to claim 4, since the minute groove portions are provided in a direction intersecting with the minute groove portions provided in the sheet passing direction of the transfer paper, a larger number of minute groove portions are provided on the separation plate. By forming it on the surface on the side through which the transfer paper passes, the surface area of the concave portion of the micro-groove portion becomes larger, so that the action of water vapor condensing on the guide surface of the separation plate can be further suppressed.

  Even when condensation occurs on the surface of the separation plate where the transfer paper passes, the condensation is caused by the minute groove provided in the direction intersecting the minute groove provided in the direction of passing the transfer paper. It is possible to disperse the water droplets due to the water vapor, and therefore it is possible to further prevent the water droplets from growing due to condensation.

  The separation plate according to claim 5 is provided with a release layer composed of a mixed material of a fluororesin and a polyimide resin or a polyamide-imide resin on the surface of the separation plate on the side through which the transfer paper passes. Thus, it is possible to prevent the toner of the transfer paper from adhering to the surface of the separation plate through which the transfer paper passes. For this reason, it is possible to prevent image defects and improve the image quality.

  The separation plate according to claim 6, wherein the separation plate is a tip portion that separates the transfer paper from the fixing member and is in contact with the fixing member, with a fluororesin and a polyimide resin or a polyamideimide resin. Therefore, it is possible to prevent the surface of the fixing member from being damaged by the tip of the separation plate coming into contact with the fixing member, thereby improving the life of the fixing member. be able to.

  The separation plate according to claim 7, wherein the release layer provided in the minute groove portion contains a fluororesin more than the release layer provided on the surface on the side through which the transfer paper except the minute groove portion passes. Since the amount is small, even when condensation occurs on the surface of the separation plate where the transfer paper passes, the condensation that occurs on the part other than the minute groove part is attracted toward the minute groove part. Therefore, it is possible to further prevent the growth of water droplets due to condensation on the surface of the separation plate on the side through which the transfer paper passes.

  According to an eighth aspect of the present invention, in the fixing device according to the first aspect, the separation plate according to any one of the first to seventh aspects is provided in the vicinity of a nip portion that includes a fixing member and a pressure member that presses the fixing member. Since the fixing device is provided, a fixing device capable of achieving high image quality can be provided at low cost.

  Since the image forming apparatus according to the ninth aspect includes the fixing device according to the eighth aspect, an image forming apparatus capable of achieving high image quality can be provided at a low cost.

  A separation plate according to a first embodiment of the present invention will be described with reference to FIGS.

  As shown in FIGS. 1 and 2, the separation plate 1 of the present invention is a transfer sheet that is discharged through a nip portion N composed of a fixing member 2 and a pressure member 3 that is in pressure contact with the fixing member 2. S is separated from the fixing member 2.

  In the present invention, the separation plate 1 has a large number of minute grooves 5 on the surface 1a on the side through which the transfer paper S passes to prevent the growth of water droplets.

  The fixing member 2 of the fixing device 4 including the fixing member 2 and the pressure member 3 that presses against the fixing member 2 is endlessly wound between a fixing roller 23 and a heating roller 22 having a heat source 21 therein. A pressure roller 31 as a pressure member 3 having a heat source 32 inside is in pressure contact with the fixing roller 23 via the fixing belt 24. A nip portion N is formed between the fixing belt 24 and the pressure roller 31, and the transfer paper S on which the toner image is formed is passed through the nip portion N, thereby adhering to the transfer paper S. The toner 6 being melted by heat is fixed on the transfer paper S by pressure.

  The separation plate 1 is provided in the vicinity of the exit portion of the nip portion N by a support shaft 7 provided at the base end portion 1b, and extends toward the exit portion of the nip portion N. 1 c faces the fixing belt 24 of the fixing device 4. As shown in FIG. 3, the separation plate 1 has a plate width 1 w that is slightly larger than the paper width Sw of the transfer paper S discharged through the nip portion N, and the leading end 1 c of the separation plate 1. The abutting portion 8 is provided on both sides of the sheet passing range 1 s and on the portion facing the fixing belt 24. The separating plate 1 is urged toward the fixing belt 24 with the support shaft 7 as a fulcrum by a spring (not shown). For this reason, the abutting portion 8 comes into contact with the surface of the fixing belt 24. Yes.

  The corner 1d of the tip 1c of the separation plate 1 is separated from the surface of the fixing belt 24 by a slight gap 1g as shown in FIG. . On the other hand, the leading end portion Sa of the transfer paper S discharged through the nip N is slightly lifted from the surface of the fixing belt 24 and discharged. For this reason, the transfer sheet S discharged from the nip portion N is formed by forming the gap 1g of the corner 1d of the leading end 1c of the separation plate 1 to be smaller than the lifting amount Sg of the transfer sheet S. The leading end 1c of the separation plate 1 passes through the surface 1a side that does not face the fixing belt 24. As a result, the transfer paper S discharged from the nip portion N is separated from the fixing belt 24, and the transfer paper S is prevented from being wound around the surface of the fixing belt 24 due to the viscosity of the melted toner.

  In the present invention, the separation plate 1 has a large number of minute grooves 5 on the surface 1a on the side through which the transfer paper S passes, as shown in FIG. The inventors of the present invention have found that the water vapor released from the transfer sheet S heated through the nip N has not been sufficiently warmed immediately after the start of the printer, on the side through which the transfer sheet S of the separation plate 1 passes. Even when the surface 1a touches the surface 1a, it is found that by providing a large number of minute grooves 5 on the surface 1a, the growth of water droplets due to the condensation can be prevented, and the transfer paper S of the separation plate 1 is The surface 1a on the passing side is provided with a large number of minute grooves 5 that prevent the growth of water droplets.

  In the present invention, the separation plate 1 has a large number of minute grooves 5 for preventing the growth of water droplets on the surface 1a on the side through which the transfer paper S passes. Even when the water vapor released from the transfer paper S touches the surface 1a on the side of the separation plate 1 through which the transfer paper S passes, which is not sufficiently warmed immediately after the start of the printer, dew condensation occurs. Growth can be prevented.

  The large number of minute grooves 5 can suppress the action of water vapor condensing on the surface 1a on the side of the separation plate 1 through which the transfer paper S passes, and also suppress the action of a plurality of water droplets being combined into one. Therefore, the growth of water droplets due to condensation can be prevented.

  Moreover, since the growth of water droplets due to condensation can be prevented simply by providing the minute groove 5 on the surface 1a on the side through which the transfer paper S of the separation plate 1 passes, the structure of the separation plate 1 is simplified. Separation plate 1 can be provided at low cost.

In the present invention, the minute groove portion 5 of the surface 1a on the side through which the transfer paper S of the separation plate 1 passes is formed in accordance with the paper width Sw of the transfer paper S as shown in FIG. It is provided toward the paper feeding direction S _1. The minute groove 5 is not provided in the corner 1d of the tip 1c of the separation plate 1.

In the present invention, the fine grooves 5 provided toward the paper feeding direction S ₁ of the transfer sheet S, the air flowing through the surface 1a on the side where the transfer sheet S of the separating plate 1 to pass through so as to be rectified ing. Therefore, the warm air heated by the pressure roller 31 having the heat source 32 in the vicinity of the outlet of the nip portion N is moved along the minute groove portion 5 from the distal end portion 1c side to the proximal end portion 1b side. Therefore, the separation plate 1 immediately after the start-up of the printer can be immediately heated, and the occurrence of condensation on the separation plate 1 can be prevented.

Further, due to the rectifying effect by the minute groove portion 5, the water vapor discharged from the transfer paper S that has passed through the nip portion N can be easily directed in the paper passing direction S ₁ of the transfer paper S, that is, toward the outside of the fixing device 4. It can be discharged. Therefore, water vapor released from the transfer paper S that has passed through the nip portion N can be discharged toward the outside of the fixing device 4, and condensation on the separation plate 1 can be prevented.

  The manufacturing method of the separation plate 1 according to the present invention will be described with reference to FIG.

  First, in the base material 9 of the separation plate 1 made of a metal such as iron, stainless steel, and aluminum, a slit 9a is provided at a portion corresponding to the tip 1c of the separation plate 1 (FIG. 4A, slit processing step).

  Next, in the base material 9 subjected to the slit processing, the rolling region 9b shown in FIG. 4A corresponding to the tip portion 1c of the separation plate 1 is rolled to form the tip portion 1c of the separation plate 1 having a predetermined thickness. At the same time, the abutting portions 8 are formed on both sides of the sheet passing range of the tip portion 1c of the rolled separating plate 1 (FIG. 4B, rolling process).

  Here, when performing the said rolling process, the front-end | tip part 1c of the separation plate 1 is rolled into a desired shape using a hydraulic press. For example, when rolling the base material 9 of an iron plate having a plate thickness of 1.6 mm and forming the thickness of the tip 1c of the separation plate 1 to 0.2 mm, using a hydraulic press machine of 150 ton to 500 ton, It is divided into several times by a first press die (not shown) manufactured according to the shape to be rolled. The larger the pressure load, the smaller the predetermined thickness can be obtained.

  The portion corresponding to the abutting portion 8 is rolled using a second press die (not shown). At this time, as described above, the abutting portion 8 is rolled so that a desired gap 1g is obtained between the corner portion 1d of the front end portion 1c of the separation plate 1 and the surface of the fixing belt 24. Further, by making the portion of the abutting portion 8 that contacts the surface of the fixing belt 24 into a curved surface, it is possible to contact the surface of the fixing belt 24 without damaging it.

  Next, the outer periphery of the base material 9 is punched by the outer peripheral punching process (FIG. 4C, punching process).

  Next, a support portion 9c that supports the support shaft of the base end portion 1b of the separation plate 1 is bent and formed in the punched base material 9 by a bending process (FIG. 4D, bending process).

  Finally, the surplus portion of the front end portion 1c of the separating plate 1 extended by the rolling is cut by a third press die (not shown) and shaped.

  In addition, a large number of minute groove portions 5 having a desired groove shape are formed on the surface 1a of the separation plate 1 on the side through which the transfer paper S passes on the contact surface of the third press die. A ridge (not shown) is provided. The excess portion of the tip 1c of the separation plate 1 is cut off and shaped, and at the same time, a large number of minute groove portions 5 are transferred and formed on the surface 1a of the separation plate 1 on the side through which the transfer paper S passes.

  As described above, when the separation plate 1 is rolled and formed, a large number of minute groove portions 5 are formed on the surface 1a of the separation plate 1 on the side through which the transfer paper S passes. Therefore, the separation plate 1 can be provided at a low cost.

  The material of the base material 9 of the separation plate 1 and the thickness of the tip 1c of the separation plate 1 can be arbitrarily determined depending on the required rigidity depending on the transfer speed of the transfer paper S, the paper width Sw of the transfer paper S, and the like. Can be decided. If the thickness of the front end portion 1c of the separation plate 1 is rolled to less than 0.1 mm, undulations and cracks are generated at the front end, causing a problem in strength. Further, if the thickness of the leading edge 1c exceeds 0.5 mm, the transfer sheet S is placed in relation to the lift amount Sg of the leading edge Sa of the transfer paper S discharged through the nip N. There are restrictions on separation from the fixing belt 24. For this reason, it can be said that 0.1 mm to 0.5 mm is an appropriate range for the thickness of the front end portion 1 c of the separation plate 1.

FIG. 5 shows the separation plate 1 according to the second embodiment of the present invention, and a large number of minute groove portions 5 are transferred on the surface 1a on the side through which the transfer paper S of the separation plate 1 of the present invention passes. provided toward the paper feeding direction S ₁ of the sheet S, moreover, as the micro-grooves 5, as shown in FIG. 5 (b), to expand toward the feed direction S ₁ of a transfer sheet S The formed groove width is 5w.

The present inventors have found that the transfer sheet S of the separating plate 1 are a number of fine grooves 5 provided on the surface 1a of the side passing, it is formed to expand toward the feed direction S ₁ of the transfer sheet S grooves It has been found that by having the width 5w, the growth of water droplets due to condensation can be further prevented, and a large number of minute grooves 5 provided on the surface 1a of the separation plate 1 on the side through which the transfer paper S passes are formed on the transfer paper S. formed groove width 5w to expand towards the feed direction S ₁ is obtained so as to have a.

In the present invention, the fine grooves 5 provided on the surface 1a on the side where the transfer sheet S of the separating plate 1 passes, the formed groove width 5w to expand toward the feed direction S ₁ of the transfer sheet S Therefore, it is possible to increase the surface area of the concave portion of the micro-groove portion 5, and to further suppress the action of water vapor on the surface 1a on the side through which the transfer paper S of the separation plate 1 passes, and therefore, In addition, the growth of water droplets due to condensation can be further prevented.

FIG. 6 shows the separation plate 1 according to the third embodiment of the present invention. The surface 1a on the side through which the transfer paper S of the separation plate 1 of the present invention passes is shown in FIG. 6 (a). as such, the micro groove 5b in a direction intersecting the fine groove 5a provided toward the paper feeding direction S ₁ of the transfer sheet S, that is, are provided in the direction orthogonal to the micro-grooves 5a.

The present inventors have found that the direction intersecting micro groove 5 provided on the surface 1a on the side where the transfer sheet S of the separating plate 1 passes, the minute groove 5a provided toward the paper feeding direction S ₁ of the transfer sheet S by constructing as small groove 5b is provided in, and found that it is possible to further inhibit the growth of water droplets due to condensation, the minute groove 5b, toward the feed direction S ₁ of the transfer sheet S It is provided in a direction intersecting with the provided minute groove 5a.

In the present invention, the minute groove 5b is so provided in a direction crossing the fine groove 5a provided toward the paper feeding direction S ₁ of the transfer sheet S, a number of fine grooves 5 of the separating plate 1 more The transfer paper S can be formed on the surface 1a on the side through which the transfer paper S passes, and by forming the surface area of the concave portion of the minute groove portion 5 larger, the surface 1a on the side through which the transfer paper S of the separation plate 1 passes the water vapor. The action of dew condensation can be further suppressed.

Even when the transfer sheet S of the separating plate 1 is as dew on the surface 1a side is generated to pass, provided in a direction crossing the fine groove 5a provided toward the paper feeding direction S ₁ of the transfer sheet S Water droplets due to dew condensation can be dispersed by the formed minute groove portions 5b, and therefore, the growth of water droplets due to dew condensation can be further prevented.

Incidentally, the minute groove 5b provided in a direction crossing the fine groove 5a provided toward the paper feeding direction S ₁ of the transfer sheet S, the surface 1a entirely on the side of the transfer sheet S of the separating plate 1 passes It is not necessary to provide it, and as shown in FIG. 6A, it is sufficient to provide it only in the part 10 where water droplets due to condensation known from experience are likely to occur. Further, the micro groove 5b is not necessarily provided in the direction orthogonal to the micro-grooves 5a provided toward the paper feeding direction S ₁ of the transfer sheet S, the minute groove 5b is passing the transfer sheet S if intersect the micro groove 5a provided toward the paper direction S ₁ is sufficient.

  Further, in the separation plate 1 according to each of the above-described embodiments, as shown in FIG. 7, toner contact after fixing to the transfer sheet S is made on the surface 1 a on the side through which the transfer sheet S discharged from the nip portion N passes. In order to improve the image quality, it is more preferable to provide the release layer 11 for preventing the toner from adhering to the surface.

  As a result of investigating the releasability on the surface 1a on the side through which the transfer paper S of the separating plate 1 passes, the present inventors have found that it has higher releasability, and the fluororesin and polyimide resin or polyamideimide A release layer 11 made of a mixed material with resin is provided on the surface 1a of the separation plate 1 on the side through which the transfer paper S passes.

  In the present invention, the release layer 11 made of a mixed material of a fluororesin and a polyimide resin or a polyamideimide resin is provided on the surface 1a of the separation plate 1 on the side through which the transfer paper S passes. The surface of 1a can be smoothed, and even when the fixed transfer paper S discharged from the nip N contacts the surface 1a, the toner of the transfer paper S adheres to the surface 1a. Therefore, it is possible to prevent image defects and improve image quality.

  In general, the release layer formed on the surface of a fixing roller or fixing belt as a fixing member often contains only 100% by weight of a fluororesin. Typical examples of the fluororesin include PTFE (polytetrafluoroethylene), PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), and FEP (tetrafluoroethylene-hexafluoroethylene copolymer). However, they have high cohesive strength and poor dispersibility. Therefore, there is a problem that a binder is required, and when firing is performed, spherulites are generated and the surface cannot be smoothed.

  For this reason, a fixing roller or the like having a release layer containing only 100% by weight of the fluororesin requires a finishing process such as polishing in order to smooth the surface.

  However, in the present invention, the release layer 11 made of a mixed material of a fluororesin and a polyimide resin or a polyamideimide resin is provided on the surface 1a of the separation plate 1 on the side through which the transfer paper S passes. The surface of the surface 1a can be smoothed, and there is no need for finishing.

  In particular, in the present invention, the release layer 11 on the surface 1a of the separation plate 1 on the side through which the transfer paper S passes is made of a material in which a polyimide resin or a polyamideimide resin is mixed with a fluororesin having 50 to 70% by weight. Since it was comprised, by making it the fluororesin made into 50 to 70 weight%, a dispersibility is favorable and a smooth surface can be obtained, and the adhesiveness with the base material which forms the release layer 11 is improved. By mixing a polyimide resin or a polyamideimide resin, the primer layer can be made unnecessary. Therefore, when forming the release layer 11 on the surface 1a of the separation plate 1 on the side through which the transfer paper S passes, it is not necessary to perform finishing processing or primer processing, thereby reducing the processing cost of the separation plate 1. Therefore, the separation plate 1 can be provided at a low cost.

  In addition, when the release layer 11 made of a mixed material of a fluororesin and a polyimide resin or a polyamideimide resin is provided on the surface 1a of the separation plate 1 on the side through which the transfer paper S passes, as shown in FIG. The front end portion 1c of the separation plate 1 for separating the transfer sheet S from the fixing member 2, and the portions that are in contact with the fixing member 2, that is, the both sides of the front end portion 1c of the separation plate 1 are provided. If a release layer 11 made of a mixed material of a fluororesin and a polyimide resin or a polyamideimide resin is provided on the surface of the abutting portion 8 that contacts the surface of the fixing belt 24, the abutting portion 8 causes the fixing belt to be fixed. It is possible to prevent the surface of 24 from being damaged, which is more preferable.

  In the present invention, the separating plate is a tip portion 1c that separates the transfer paper S from the fixing member 2 and is in contact with the fixing member 2 with fluorine resin and polyimide resin or polyamideimide resin. Since the release layer 11 made of the mixed material is provided, it is possible to prevent the surface of the fixing member 2 from being damaged by the tip 1c of the separation plate 1 coming into contact with the fixing member 2, and the life of the fixing member 2 can be shortened. Can be improved.

  Further, as shown in FIG. 8, among the release layer 11 on the surface 1 a of the separation plate 1 on the side through which the transfer paper S passes, the release layer 11 a provided in the minute groove portion 5 defines the minute groove portion 5. The surface 1a of the separation plate 1 on the side through which the transfer paper S passes is that the release layer 11b provided on the surface 1a on the side through which the transfer paper S is removed has a smaller content of fluororesin. It is more preferable for preventing the growth of water droplets due to dew condensation.

  The inventors change the fluororesin content of the release layer 11 provided on the surface 1a on the side through which the transfer sheet S of the separation plate 1 passes, thereby allowing the transfer sheet S of the separation plate 1 to pass through. It is found that the growth of water droplets due to condensation on the side surface 1a can be further prevented, and the transfer paper S excluding the minute groove portion 5 passes through the release layer 11a provided in the minute groove portion 5. The fluororesin content is less than that of the release layer 11b provided on the side surface 1a.

  In the present invention, the release layer 11a provided in the minute groove portion 5 contains a fluororesin than the release layer 11b provided on the surface 1a on the side through which the transfer paper S excluding the minute groove portion 5 passes. Since the amount is configured to be small, even when dew condensation occurs on the surface 1a of the separation plate 1 on the side through which the transfer paper S passes, the dew condensation generated on the portion other than the minute groove portion 5 is caused to the minute groove portion 5. Therefore, the growth of water droplets due to condensation on the surface 1a of the separation plate 1 on the side through which the transfer paper S passes can be further prevented.

  The fixing device 4 (FIG. 1) including the separation plate 1 according to the embodiment of the present invention described above is wound as a fixing member 2 between a heating roller 22 having a heat source 21 inside and a fixing roller 23. An endless fixing belt 24 and a pressure roller 31 as a pressure member 3 that is disposed to face the fixing roller 23 with the fixing belt 24 interposed therebetween and has a heat source 32 therein are provided. Then, the transfer paper S on which the toner image is formed is passed through the nip portion N between the fixing belt 24 and the pressure roller 31 to melt the toner 6 adhering to the transfer paper S by heat. The toner image is fixed on the transfer paper S by pressurization.

  In the vicinity of the exit portion of the nip portion N, a separation plate 1 is provided by a support shaft 7 provided at the base end portion 1b, and the distal end portion 1c of the separation plate 1 extends toward the exit portion of the nip portion N. However, it faces the fixing belt 24. As shown in FIG. 3A, the separation plate 1 has a plate width 1w that is slightly larger than the paper width Sw of the transfer paper S discharged through the nip portion N. Abutting portions 8 are provided on both sides of the front end portion 1c and facing the fixing belt 24. The separating plate 1 is urged toward the fixing belt 24 with the support shaft 7 as a fulcrum by a spring (not shown). For this reason, the abutting portion 8 comes into contact with the surface of the fixing belt 24. Yes.

  The corner 1d of the tip 1c of the separation plate 1 is separated from the surface of the fixing belt 24 by a slight gap 1g as shown in FIG. . On the other hand, the leading end portion Sa of the transfer sheet S discharged through the nip portion N is slightly lifted from the surface of the fixing belt 24 and discharged, so that the corner portion 1d of the leading end portion 1c of the separation plate 1 is discharged. By forming the gap 1g to be smaller than the lifting amount Sg of the transfer sheet S, the surface 1a where the transfer sheet S discharged from the nip portion N does not face the fixing belt 24 of the front end portion 1c of the separation plate 1. It is designed to pass through the side. As a result, the transfer paper S discharged from the nip portion N is separated from the fixing belt 24, and the transfer paper S is prevented from being wound around the surface of the fixing belt 24 due to the viscosity of the melted toner.

  In the fixing device 4 of the present invention, the separation plate 1 according to any one of the first to seventh aspects is in the vicinity of a nip portion N constituted by a fixing member 2 and a pressure member 3 that presses against the fixing member 2. Therefore, it is possible to reduce the cost of the fixing device 4 that can improve the image quality by configuring the separation plate 1 at a low cost and preventing the growth of water droplets due to condensation. Can be provided.

  The image forming apparatus P (FIG. 9) having the fixing device 4 including the separation plate 1 according to the embodiment of the present invention described above is a full color printer as a color image forming apparatus. A two-stage sheet feeding unit 12 is disposed below the image forming apparatus P, and an image forming unit 13 is disposed above the sheet feeding unit 12.

The image forming apparatus P has a heat capacity higher than that of plain paper generally used for copying, etc., 90K paper such as OHP sheets, cards, and postcards, and plain paper such as thick paper and envelopes having a basis weight of about 100 g / m ² or more. Any of the large special sheets can be used as the transfer paper S.

  The image forming unit 13 is provided with a transfer belt device 14 which is disposed so as to be inclined with the paper feed side facing down and the paper ejection side facing up. The transfer belt device 14 has an endless transfer belt 14a wound around a plurality of roller groups, and one of the rollers is driven by a driving source so that the transfer belt runs. ing. Four image forming units 15M and 15C for magenta (M), cyan (C), yellow (Y), and black (Bk) are sequentially arranged on the upper running side of the transfer belt from the upstream side in the running direction of the transfer belt 14a. , 15Y, 15Bk are arranged in parallel. Further, the fixing device 4 described above is disposed on the downstream side of the transfer belt 14a in the running direction.

  Each of the image forming units 15M, 15C, 15Y, and 15Bk is provided with a photoconductor 16 as an image carrier, and the photoconductor 16 is driven to rotate clockwise in FIG. 9 by a driving unit (not shown). It is supposed to be. Around the photosensitive member 16, a charging roller 17 as a charging unit, an optical writing unit 18 for performing laser beam writing as an exposure unit, a developing device 19, and a cleaning device 20 are sequentially provided.

  In the image forming apparatus P, first, in the magenta image forming unit 15M, the photosensitive member 16 is charged by the charging roller 17, exposed by laser light to form an electrostatic latent image on the photosensitive member 16, and this electrostatic latent image is formed. The image is developed using the developing device 19 to be visualized as a magenta toner image. On the other hand, a predetermined transfer sheet S is fed from the paper supply unit 12 onto the transfer belt 14a, and the transfer sheet S reaches a transfer position facing the photoconductor 16 by the travel of the transfer belt 14a. ing. At the transfer position, the magenta toner image is transferred onto the transfer paper S by the action of the transfer roller 14b provided on the back side of the transfer belt 14a.

  Similarly, toner images are formed in the other image forming units 15C, 15Y, and 15Bk, and these toner images are sequentially transferred to the transfer sheet S conveyed by the transfer belt 14a. .

  Then, the transfer sheet S, which has been transferred by all of the image forming units 15M, 15C, 15Y, and 15Bk, is sent to the fixing device 4, and the toner adhering to the transfer sheet S is melted by heat. It is fixed on the transfer paper S by pressurization. The fixing device 4 is provided with the separation plate 1 described above, and prevents the transfer paper S discharged from the fixing device 4 from being wound around the surface of the fixing belt 24 due to the viscosity of the melted toner. .

  Since the image forming apparatus P according to the present invention includes the fixing device 4 according to the eighth aspect, the separation plate 1 is configured to be low-cost and prevent the growth of water droplets due to condensation. Thus, by reducing the cost and improving the image quality of the fixing device 4 provided with the separation plate 1, it is possible to provide the image forming apparatus P capable of improving the image quality at a lower cost.

  The above-described embodiments are merely representative examples of the present invention, and the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention. .

  That is, in the separation plate 1 according to the above-described embodiment, the corner 1d of the tip 1c of the separation plate 1 is brought into contact with the fixing belt 24 of the abutting portion 8 provided at the tip 1c. However, the corner 1d of the front end 1c of the separation plate 1 is in direct contact with the surface of the fixing belt 24 without providing the abutting portion 8 at the front end 1c. Any configuration is acceptable. In such a configuration, if the release layer made of the above-mentioned mixed material is provided on the surface of the corner 1d of the tip 1c of the separation plate 1, damage to the surface of the fixing belt 24 can be prevented. preferable.

  In the fixing device 4 described above, the fixing member 2 includes a fixing belt 24 wound between a heating roller 22 having a heat source 21 therein and a fixing roller 23, and the fixing roller 24 is interposed via the fixing belt 24. Although the configuration in which the pressure roller 31 is in pressure contact with the pressure roller 31 has been described, the fixing member 2 may be configured such that the pressure roller 31 is in direct pressure contact with a fixing roller having a heat source therein. In any configuration, it is sufficient if the separation plate 1 according to the present invention is disposed in the vicinity of the exit portion of the nip portion N of the fixing device 4.

  In the image forming apparatus P described above, a full color printer has been described as an example. However, a monochrome printer may be used. In any printer, it is sufficient if the separation plate 1 according to the present invention is disposed in the vicinity of the exit portion of the nip portion N of the fixing device 4.

Example 1
(A) A slit 9a having a width of 5 mm is formed on a base material 9 made of a hot dip galvanized steel sheet (SGCD1) having a thickness of 1.6 mm and a size of 400 mm × 200 mm using Aida Engineering's high flex press NS-2 300ton. Forming step,
(B) The rolling region 9b, which is a portion corresponding to the tip portion 1c of the separating plate 1, is rolled to a thickness of 0.2 mm over a width 3 mm next to the slit 9a of the substrate 9, and the separating plate A step of rolling a portion corresponding to one butting portion 8 to a thickness of 0.35 mm;
(C) a step of punching the outer periphery of the base material 9;
(D) a step of bending the punched base material 9;
(E) A large number of ridges are formed by etching on the contact surface of the press die when the excess portion corresponding to the tip portion 1c of the rolled separation plate 1 is cut off and shaped. A step of transferring and forming a large number of minute grooves 5 in the sheet passing direction S ₁ of the transfer sheet S on the surface 1 a on the side through which one transfer sheet S passes;
(F) the entire surface 1a of the separation plate 1 through which the transfer paper S passes, the rolling region of the front end portion 1c of the separation plate 1, the abutting portions 8 on both sides of the front end portion 1c, and the front end portion 1c; Fluorine resin paint in which 60% by weight of PTFE (polytetrafluoroethylene) resin, 35% by weight of polyimide resin, and 5% by weight of carbon black as an additive is sprayed on the corner 1d by spray coating, 150% A step of forming the release layer 11 by firing after leaving at 360 ° C. for 20 minutes in an atmosphere of 360 ° C .;
The separator 1 was obtained through these steps. Here, the shape of the minute groove portion 5 of the separation plate 1 is such that the groove width 5w shown in FIG. 3C is 100 μm, the groove depth 5d is 15 μm, and the interval 5p between adjacent grooves is 0.5 mm.

(Example 2)
Minute groove 5 of the separating plate 1 in Example 1 was formed to have a groove formed width 5w to expand toward the feed direction S ₁ of the transfer sheet S. As shown in FIG. 5B, the groove width 5w of the minute groove portion 5 is 100 μm at the upstream end in the sheet passing direction S ₁ of the transfer sheet S and 400 μm at the downstream end, and the shapes of the other minute groove portions are as follows. In the same manner as in Example 1. A separator plate 1 was obtained in the same manner as in Example 1 except as described above.

(Example 3)
Minute groove 5 of the separating plate 1 in Example 1 was formed as fine groove 5b is provided in a direction orthogonal to the micro-grooves 5a provided toward the paper feeding direction S ₁ of the transfer sheet S. The shape of the minute groove 5b in the orthogonal direction was the same as that of the minute groove 5a of Example 1. Further, the minute groove portion 5b was formed only in the portion 10 where water droplets due to condensation of the separation plate 1 found by the present inventors were likely to occur. A separator plate 1 was obtained in the same manner as in Example 1 except as described above.

Example 4
In the separation plate 1 in Example 1, the release layer 11a formed on the surface of the micro-groove portion 5 is 30% by weight of PTFE (polytetrafluoroethylene) resin, 60% by weight of polyimide resin, and 10% of carbon black. It was formed by masking and applying a fluororesin paint in which weight% was dispersed. A separator plate 1 was obtained in the same manner as in Example 1 except as described above.

(Comparative Example 1)
A separation claw made of polyimide resin already mounted on a fixing unit of a color printer (IPSIO8000, manufactured by Ricoh) was used.

(Comparative Example 2)
A separation sheet having a configuration disclosed in JP-A-2002-91222 was used. A steel sheet with a thickness of 1.6 mm is joined to a support member made of a hot-dip galvanized steel sheet by laser spot welding to form a separation sheet, sprayed with a silicone primer, and dried at 150 ° C. Thereafter, a fluororesin tape was attached so as to wrap the leading end from the paper passing side surface to the back surface of the leading end portion of the separating sheet to obtain the separating sheet.

(Comparative Example 3)
The separation plate 1 in Example 1 was configured such that the minute groove portions 5 were not formed, and the separation plate 1 was obtained in the same manner as in Example 1 except for the above.

  The separation plate 1 of Examples 1 to 4 and Comparative Examples 1 to 3, or the separation claw or separation sheet corresponding to the separation plate 1 is attached to the fixing unit of a color printer (IPSIO8000, manufactured by Ricoh Company). A paper passing test was conducted. In mounting on the actual machine, the abutting portion 8 of the separation plate 1 was brought into contact with the surface of the fixing belt 24 so as to be the same as the contact pressure load 0.25 N of the separation claw (Comparative Example 1).

In the sheet passing test, a transfer sheet S made of plain paper having a margin of 3 mm in width at the leading end in the sheet passing direction S ₁ formed with a red solid image that is a two-color image of magenta M and yellow Y,
(A) Continuously passing 120K sheets, which is the guaranteed number of products, and checked for image defects.
(B) Five sheets of the transfer paper S left for 12 hours in an environment of a temperature of 30 ° C. and a humidity of 90% RH were passed immediately after the start of the actual machine to confirm the presence or absence of image defects. The results are shown in Table 1. As is clear from Table 1, image defects did not occur when the separation plate 1 of Examples 1 to 4 according to the present invention was configured as compared with the contact type separation claw (Comparative Example 1). . Furthermore, even when compared with Comparative Example 2 or 3, no image defect (white image) due to adhesion of water droplets immediately after the start-up of the actual machine was observed, and the effect of preventing water droplet growth due to condensation could be confirmed.

1 is a schematic configuration diagram illustrating a fixing device including a separation plate according to a first embodiment of the present invention. FIG. 2 is a schematic configuration diagram in which a separation plate portion of the fixing device illustrated in FIG. 1 is enlarged. FIG. 3A shows a separation plate of the fixing device shown in FIG. 1, FIG. 3A is a plan view showing the surface of the separation plate through which transfer paper passes, and FIG. The figure which expanded the A section and FIG.3 (c) is the II sectional view taken on the line of FIG.3 (b). It is a figure explaining the manufacturing method of a separator, FIG.4 (a) is a slit process process of a base material, FIG.4 (b) is a rolling process process of a base material, FIG.4 (c) is a punching process process of a base material, FIG.4 (d) is a perspective view explaining the bending process of a base material. FIG. 5A shows a separation plate according to a second embodiment of the present invention. FIG. 5A is a plan view showing a surface of the separation plate on the side through which transfer paper passes, and FIG. 5B is an enlarged view of part B, FIG. 5C is a cross-sectional view taken along the line II-II of FIG. 5B, and FIG. 5D is a cross-sectional view taken along the line III-III of FIG. 6A and 6B show a separation plate according to a third embodiment of the present invention, in which FIG. 6A is a plan view showing a surface of the separation plate through which transfer paper passes, and FIG. It is the figure which expanded the C section of (). It is sectional drawing which shows the mold release layer formed in the surface at the side through which the transfer paper of a separating plate passes. In the cross-sectional view showing the release layer formed on the surface of the separation plate on the side where the transfer paper passes, the material of the release layer formed in the minute groove and the release layer formed in the part other than the minute groove are different It is. 1 is a schematic configuration diagram illustrating an image forming apparatus having a fixing device including a separation plate according to an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Separator plate 1a Surface on which transfer paper passes 1b Base end 1c Tip 1d Corner 1g Gap 1s Paper passing range 1w Plate width 2 Fixing member 21 Heat source 22 Heating roller 23 Fixing roller 24 Fixing belt 3 Pressing member 31 Pressure roller 32 Heat source 4 Fixing device 5 Minute groove portion 5a Minute groove portion in the sheet passing direction 5b Minute groove portion in the direction perpendicular to the minute groove portion in the sheet passing direction 5d Groove depth 5p Groove interval 5w Groove width 6 Toner 7 Support shaft 8 Abutting part 9 Substrate 9a Slit 9b Rolling area 9c Support part 10 Part where water droplets are easily generated 11 Release layer 11a Release layer of minute groove 11b Release layer 12 on the surface through which transfer paper excluding the minute groove passes Paper feeding unit 13 Image forming unit 14 Transfer belt device 14a Transfer belt 14b Transfer roller 15M, 15C, 15Y, 15Bk Image forming unit 16 Photoconductor 17 Charging roller 18 Optical writing unit 19 Developing device 20 Cleaning device N Nip part P Image forming device S Transfer paper Sa Tip Sg Lifting amount Sw Paper width S ₁ Paper feeding direction

Claims (9)

In the separation plate in which the transfer paper discharged through the nip portion composed of the fixing member and the pressure member pressed against the fixing member is separated from the fixing member,
The separation plate has a large number of minute grooves on the surface on the side through which the transfer paper passes to prevent the growth of water droplets.   The separation plate according to claim 1, wherein the minute groove portion is provided in a paper passing direction of the transfer paper.   The separation plate according to claim 2, wherein the minute groove portion has a groove width formed so as to expand toward the sheet passing direction of the transfer paper.   The separation plate according to claim 2, wherein the minute groove portion is provided in a direction intersecting with the minute groove portion provided toward the sheet passing direction of the transfer paper.   The separation according to claim 1, wherein a release layer composed of a mixed material of a fluororesin and a polyimide resin or a polyamideimide resin is provided on a surface of the separation plate on a side through which the transfer paper passes. Board.   A release layer composed of a mixed material of a fluororesin and a polyimide resin or a polyamide-imide resin is provided on a portion where the separation plate separates the transfer paper from the fixing member and is in contact with the fixing member. The separation plate according to claim 5, wherein the separation plate is provided.   The release layer provided in the minute groove part is configured so that the content of the fluororesin is less than the release layer provided on the surface through which the transfer paper except the minute groove part passes. The separator according to claim 5 or 6.   The fixing plate according to any one of claims 1 to 7, wherein the separation plate is provided in the vicinity of a nip portion constituted by a fixing member and a pressure member pressed against the fixing member. apparatus.   An image forming apparatus comprising the fixing device according to claim 8.

Images