JP2007065526A - Image heating device and electrophotographic image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image heating device capable of restraining a situation that resin projecting from recording material adheres to the inside of next different-size recording material to cause an image defect even when the thermal fixing of the different-size recording material is performed, and an electrophotographic image forming apparatus. <P>SOLUTION: The image heating device has: a fixing belt 114 heating a toner image T formed on the recording material P equipped with a transparent resin layer Pb; halogen lamps 117 and 118 heating the fixing belt 114; and a cooling fan 116 cooling the already heated recording material P moving together with the fixing belt 114 before separation. The contact areas X1 to X4 of the fixing belt 114 with the recording material P equipped with the transparent resin layer Pb are set for every size. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image heating apparatus for heating and fixing a developer image and an electrophotographic image forming apparatus including the same.

  Conventionally, in an image heating apparatus for a recording material provided with a resin layer on the surface, an offset phenomenon may occur where the resin on the surface of the recording material oozes slightly around the recording material on the fixing belt and adheres to the fixing belt. . Then, when the next recording material is placed on the offset resin, there is a problem that the recording material adheres to the recording material and damages the image of the recording material.

  In view of this, an image heating apparatus has been proposed in which a recording material is arranged at a predetermined position on a fixing belt so that a resin adheres to a portion of the subsequent recording material to be cut (Patent Document 1).

JP 2004-109860 A

  However, in the technique described in Patent Document 1, as shown in FIG. 11, when a large size recording material P1 is used after using a small size recording material P2, an image of the large size recording material P1 is damaged. There is a problem that is given. This is because the resin Y4 offset from the small size recording material P2 to the fixing belt 114 adheres to the inside (the portion where the image is recorded) of the portion of the large size recording material to be cut.

  Accordingly, the present invention provides an image heating apparatus and a heating apparatus capable of preventing the resin protruding from the recording material from adhering to the inside of the next recording material of a different size and causing an image defect even when heat-fixing of recording materials of different sizes is performed. An object is to provide an electrophotographic image forming apparatus.

  In order to solve the above problems, a typical configuration of an image heating apparatus according to the present invention includes an endless belt that heats a toner image formed on a recording material including a resin layer, and a heating unit that heats the belt. In an image heating apparatus having a cooling unit that cools a heated recording material that moves with the belt before separation, a contact area with the recording material provided with the resin layer of the belt is set for each size of the recording material. It is characterized by that.

  In addition, a typical configuration of the electrophotographic image forming apparatus according to the present invention includes an image forming unit that forms a toner image on a recording material, the image heating device, and a timing at which the recording material is conveyed toward the belt. Control means for controlling.

  According to the present invention, even when a recording material of a different size is heat-fixed, the resin protruding from the recording material adheres to the inside of the next recording material of a different size and damages the image of the next recording material of a different size. It is possible to suppress image defects.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. In addition, what attached | subjected the same code | symbol in each drawing has the same structure or effect | action, The duplication description about these was abbreviate | omitted suitably.

  FIG. 1 shows an example of an image forming apparatus. In FIG. 1, an electrophotographic color printer using a rotary 4A on which one image carrier 1 and a plurality of developing devices 4 (developing devices 41 to 46) provided around the image carrier 1 are mounted. Hereinafter, it is referred to as an “image forming apparatus”.

  First, a schematic configuration of the image forming apparatus will be described with reference to FIG. The image forming apparatus 10 includes a digital color image printer unit (hereinafter referred to as “printer unit”) A and a digital color image reader unit (hereinafter referred to as “reader unit”) B provided on the upper part of the printer unit A. ing.

  In the printer unit A, a drum-type electrophotographic photosensitive member (hereinafter referred to as “photosensitive drum”) 1 as an image carrier is disposed so as to be rotatable in an arrow direction. Around the photosensitive drum 1, a primary charger 2 as a charging means, a laser exposure optical system 3 as an exposure means, a developing device 4 as a developing means, and an intermediate as an intermediate transfer body are arranged almost in order along the rotation direction. A transfer belt 5 and a cleaning device 6 as a cleaning unit are disposed.

  The developing device 4 described above has a rotatable rotary 4A and a plurality of developing devices mounted on the rotary 4A. Here, six developing devices 41 to 46 are illustrated as a plurality of developing devices. The six developing devices 4 include a cyan developing device 41 containing dark cyan toner as a developer, a magenta developing device 42 containing dark magenta toner, a yellow developing device 43 containing yellow toner, and a black toner. Is a black developing device 44 in which a light cyan toner is stored, a light cyan developing device 45 in which a light cyan toner is stored, and a light magenta developing device 46 in which a light magenta toner is stored.

  That is, the image forming apparatus of this example has a combination of magenta and cyan with the same hue and different brightness. That is, dark toner developing devices 41 and 42 containing light magenta and light cyan as low-lightness toners (dark color toner) and light magenta and light cyan as high-lightness toners (light color toner), respectively, and light color Two types of toner developing devices 45 and 46 are provided. Here, the yellow developing device 43 and the black toner developing device 44 having the same hue and not having different lightness are also dark toner developing devices.

  The toners having the same hue and different lightness usually refer to toners having the same spectral characteristics and different amounts of color components (pigments) contained in a toner based on resin and color components (pigments). . The toner having a high lightness means a toner having a relatively low density among a combination of toners having the same hue and different lightness.

The same hue means that the color developing components (pigments) have the same spectral characteristics as described above, but generally they are not exactly the same, such as magenta, cyan, yellow, black, etc. In addition, a range that can be called the same color in terms of the normal color concept. Toner having the same hue and high brightness has an optical density after fixing of less than 1.0 per 0.5 mg / cm ² of toner on the recording material, and low toner has a toner amount of 0 on the recording material. The optical density after fixing is 1.0 or more per 0.5 mg / cm ² . In this example, dark toners, dark cyan, dark magenta, yellow, and black, have a post-fixing optical density of 1.6 when the applied amount of toner on the recording material is 0.5 mg / cm ^2. So that the amount of pigment is adjusted. Further, light cyan and light magenta, which are light color toners, are designed such that the applied density is 0.5 mg / cm ² and the optical density after fixing is 0.9. The two gradations of toner are mixed well to reproduce the gradation of each color toner.

  Further, the developer contained in each of the developing devices 41 to 46 is a two-component developer used by mixing toner and carrier, but there is no problem even if the toner is a single-component developer. In addition, as the toner types, combinations with different brightness are provided for two colors of cyan and magenta. However, the present invention is not limited to these two types, and the brightness is different for all colors for cyan only, magenta only, yellow only, and the like. A combination may be provided. In other words, any hue may have a combination with different brightness. Accordingly, the number of developing devices is six in this example, but is not limited thereto.

  The above-described intermediate transfer belt 5 is stretched around a driving roller 51, tension rollers 52 and 54, and a secondary transfer counter roller 53. A primary transfer roller 50 that presses the intermediate transfer belt 5 against the photosensitive drum 1 is disposed inside the intermediate transfer belt 5. A secondary transfer roller 55 is disposed at a position corresponding to the secondary transfer counter roller 53 outside the intermediate transfer belt 5.

  In the lower part of the printer unit A, the feeding cassettes 11, 12, 13, feeding rollers 14, 15, 16 and the conveying rollers are sequentially arranged from the upstream side in the conveying direction of the recording material to be image-formed. 17, 18, 19, and a registration roller 20 are disposed. Further, a conveying belt 21 stretched around the rollers 22 and 23, a heat roller fixing device 9 as a first image heating device, a discharge roller 24, and the like are disposed. The heat roller fixing device 9 is provided with a fixing roller 91, a pressure roller 92, and a fixing roller cleaner 93. Further, the printer unit A is provided with a duplex conveyance path 25, a manual feed tray 26, a feeding roller 27, and the like.

  In the reader section B, an original table glass 31, an original pressing plate 32, an exposure lamp 33, reflection mirrors 34, 35, and 36, a lens 37, a full color CCD sensor 38, and the like are disposed.

  In the image forming apparatus, at the time of image formation, the document is placed on the platen glass 31 with the image surface facing downward in the reader unit B and pressed by the document pressing plate 32. The image surface of the original is exposed and scanned by the exposure lamp 33. The reflected light image from the original is condensed on the full color CCD sensor 38 by the lens 37 to obtain a color separation image signal. The color-separated image signal is subjected to image processing by a video processing unit (not shown) through an amplifier circuit (not shown), and sent to the printer unit A via an image memory (not shown).

  In addition to the signal from the reader unit B, an image signal from a computer as an external device, an image signal from a FAX, and the like are similarly sent to the printer unit A.

  Here, as an example, the operation of the printer unit A based on the signal from the reader unit B will be described.

  At the time of image formation, the photosensitive drum 1 is rotationally driven at a predetermined process speed (circumferential speed) in a direction indicated by an arrow by a driving unit (not shown), and the surface thereof is uniformly charged to a predetermined polarity and potential by a primary charger 2. (Charging process).

  An electrostatic latent image is formed on the surface of the photosensitive drum 1 after charging by the laser exposure optical system 3. An image signal from the reader unit B is converted into an optical signal by a laser output unit (not shown). The laser beam converted into the optical signal is reflected by the polygon mirror 3a, and irradiated to the charged photosensitive drum 1 surface through the lens 3b and each reflecting mirror 3c. As a result, each separation color is exposed by the laser exposure optical system 3 to form an electrostatic latent image on the photosensitive drum 1 (exposure process).

  Next, the rotary 4A is rotated, and a predetermined developing device is moved to the developing position on the photosensitive drum 1. Then, the developing device at the development position is operated to develop the latent image on the photosensitive drum 1, and a developer image (toner image) based on resin and pigment is formed on the photosensitive drum 1 (developing step). .

  The toner in each developing device has a constant toner ratio (or toner amount) in each developing device 41 to 46 from the toner storage units (hoppers) 61 to 66 for each color disposed on the laser exposure optical system 3. It is replenished as needed at a desired timing. Further, a photo sensor 70 as density detecting means is arranged on the photosensitive drum 1 so that the toner amount on the photosensitive drum 1 can be detected.

  The toner image thus formed on the photosensitive drum 1 is primarily transferred onto the intermediate transfer belt 5 by the primary transfer roller 50 (primary transfer process). After the toner image is transferred, the toner (residual toner) remaining on the surface of the photosensitive drum 1 is removed by the cleaning device 6 (cleaning process), and is used for image formation of the next color. The above-described image forming processes of charging, exposure, development, primary transfer, and cleaning are similarly repeated for the necessary colors from among the six colors. As a result, toner images of a plurality of colors are superimposed on the intermediate transfer belt 5.

  The toner images superposed on the intermediate transfer belt 5 in this way are collectively secondary-transferred onto the recording material by the secondary transfer roller 55. The recording material P is selectively fed from the feeding cassettes 11 to 13 and is synchronized with the toner image on the intermediate transfer belt 5 by the registration roller 20 so that the intermediate transfer belt 5 and the secondary transfer roller 55 Is supplied to the secondary transfer section. After the toner image has been transferred, the toner (residual toner) remaining on the surface of the intermediate transfer belt 5 is removed by a belt cleaner 56 and used for the next primary transfer.

  In the intermediate transfer belt 5, a detection sensor 57 that detects the positional deviation and density of the image transferred from the photosensitive drum 1 is disposed opposite the driven roller 52. The image forming apparatus main body control unit (not shown) corrects the image density, the toner supply amount, the image writing timing, the image writing start position, and the like at any time based on the detection result of the detection sensor 57.

  The recording material P onto which the toner image has been transferred as described above is conveyed to the heat roller fixing device 9 by the conveying belt 21. In the heat roller fixing device 9, the recording material P is supplied to the fixing nip portion between the fixing roller 91 and the pressure roller 92 pressed against the recording material P, and is heated and pressed to fix the toner image on the surface. The Thereby, the image formation on one side of the recording material P is completed.

  When images are formed on both sides of the recording material P, a conveyance path guide (not shown) is driven immediately after the recording material P passes through the heat roller fixing device 9, and the recording material P passes through the conveyance path 28. It leads to the reverse path 29 once. Thereafter, the recording material P is retreated in the direction opposite to the feeding direction from the trailing edge when fed by the reverse rotation of the reversing roller 30 and sent to the duplex conveyance path 25. Thereafter, the recording material P passes through the double-sided conveyance path 25, skew correction and timing are performed by the double-sided conveyance roller, and are conveyed to the registration roller 20 at a desired timing. Thereafter, the toner image is transferred to the other surface again by the above-described image forming process, and then fixed. Thereby, the image formation on both sides of the recording material P is completed.

(Option unit 100)
Further, as shown in FIG. 1, an optional unit 100 including a second image heating device 110 for a recording material having a transparent resin layer Pb made of a thermoplastic resin on the surface is attached to and detached from the image forming apparatus described above. It is installed freely. That is, the image forming apparatus shown in FIG. 1 includes the above-described heat roller fixing device 9 as the first image heating device and a belt fixing device 110 as the second image heating device described later.

  Here, details of the option unit 100 including the belt fixing device 110 will be described.

  In addition to the belt fixing device 110, a switching guide 101 is disposed in the option unit 100. The switching guide 101 conveys the recording material P fixed by the heat roller fixing device 9 as it is toward the discharge tray 102 provided on the upper surface of the option unit 100 or passes through the belt fixing device 110. To transfer to the belt fixing device 110. A discharge tray 103 on which the recording material P fixed by the belt fixing device 110 is placed is disposed on the side surface of the option unit 100. In addition, roller pairs 104, 105, and 106 for conveying the recording material P are arranged at appropriate positions.

  FIG. 2 is a schematic cross-sectional view of the belt fixing device 110. The belt fixing device 110 includes a fixing roller 111 as a heating rotator having a heating means (heat source), and a separation roller 112 disposed at a predetermined distance from the fixing roller 111. A fixing belt 114 as an endless endless belt is suspended between the two rollers 111 and 112. A pressure roller 115 as a pressure rotator is pressed against the fixing roller 111 across the fixing belt 114. In addition, as a cooling means for cooling the recording material P after heating that moves together with the fixing belt 114 in close contact with the fixing belt 114 between the fixing roller 111 and the separation roller 112 inside the fixing belt 114. A cooling fan 116 is provided.

  Inside the fixing roller 111 and the pressure roller 115, halogen lamps 117 and 118 as heating means (roller heater) for heating the fixing belt 114 are disposed. Note that the heating means (heat source) is not limited to the halogen heater, and a configuration in which the fixing roller is heated by electromagnetic induction using a magnetic flux generated from the exciting coil may be employed.

  The fixing roller 111 and the pressure roller 115 are pressed against each other with a predetermined pressing force across the fixing belt 114 to form a fixing nip portion N as a heating / pressing portion having a predetermined width in the recording material conveyance direction. The halogen lamps 117 and 118 are set so that the temperature at the fixing nip portion N is 180 ° C. by detection means and control (not shown).

  In the fixing belt 114, the surface of the belt that is in close contact with the image formed on the recording material P has a mirror shape so as to form a high gloss image. The fixing belt 114 of this example has a silicone rubber as an elastic layer on a polyimide resin, and a polyimide silicon resin is coated thereon as a release layer.

  The cooling fan 116 has fins 116 a that come into contact with the fixing belt 114 and cool the heat of the fixing belt 114. The fixing belt 114 is forcibly cooled to a predetermined temperature by the cooling fan 116 having the fins 116a. Note that the cooling means is not limited to the cooling fan having the above-described fins, and may be a configuration of only a cooling fan that cools the fixing belt in a non-contact manner. Further, a Peltier element, a heat pipe, or a water circulation type cooling device that cools in contact with the fixing belt may be used.

The recording material P used in such a belt cooling and fixing device is a toner receiving layer (transparent) on the top and bottom of a recording material base layer Pa such as paper or RC paper (resin coated paper) provided with a resin layer such as polyethylene on the top and bottom of the paper. It is a recording material P (resin coated paper or the like) coated with a thermoplastic resin to be a resin layer Pb). The recording material P of this example is formed by coating a polyethylene resin on the recording material base layer, and further coating a polyester resin (the same resin as the toner) that is compatible with the toner. The amount of the polyester resin is about 15 g / m ² , and the basis weight of the entire recording material is 200 g / m ² .

  A toner image is formed on such a recording material by the image forming method described above. That is, a toner image is formed on the polyester resin layer and fixed by the heat roller fixing device 9 of the image forming apparatus main body 10. As shown in FIG. 3A, in this state, the toner image T is only fixed on the polyester resin layer. Thereafter, the belt fixing device 110 shown in FIG. 2 is entered.

  The fixing roller 111 is rotationally driven in a clockwise direction at a predetermined speed by a driving mechanism (not shown). By the rotation driving of the fixing roller 111, the fixing belt 114 rotates clockwise at a predetermined speed (in this example, 50 mm / s). The separation roller 112 and the pressure roller 115 are driven to rotate as the fixing belt 114 rotates. The separation roller 112 also functions as a tension roller that applies a predetermined tension to the fixing belt 114.

  The recording material P sent to the belt fixing device 110 is introduced between the fixing belt 114 and the pressure roller 115 of the fixing nip portion N and is nipped and conveyed through the fixing nip portion N. At that time, due to the heat from the fixing roller 111 and the pressure roller 115, the temperature of the transparent resin layer Pb rises and becomes softer together with the toner T, and further, pressure from the fixing roller 111 and the pressure roller 115 is applied. As shown in FIG. 3B, the toner image T is buried in the high temperature transparent resin layer. At the same time, the recording material P is in close contact with the surface of the fixing belt 114. At this time, the surface of the recording material having the toner image T is made uniform along the surface property of the fixing belt 114.

  The recording material P in which the toner image T is embedded in the transparent resin layer is conveyed to the separation portion by the separation roller 112 while being in close contact with the surface of the fixing belt 114. The recording material P in close contact with the fixing belt 114 is efficiently and forcibly cooled by the cooling fan 116 until reaching the separation portion (cooling region). That is, the toner image is cooled to a temperature (about 50 ° C.) lower than the softening point temperature (glass transition temperature) of the toner. Accordingly, the recording material P is easily peeled off from the fixing belt 114 in combination with the releasability of the fixing belt surface.

  Then, as shown in FIG. 4, the recording material P adhered to the surface of the fixing belt 114 is sufficiently cooled in the cooling region, and then the fixing belt 114 is separated at the separation portion where the curvature of the fixing belt 114 is changed by the separation roller 112. Is peeled off (curvature separation) by its own stiffness.

  By performing the cooling separation in this way, it is possible to finish the surface of the recording material P so as to have no unevenness substantially corresponding to the mirror-like surface of the fixing belt 114. Therefore, if the above-described belt fixing device 110 is used, a high-quality image having a gloss level comparable to that of a silver-lead photograph can be obtained.

(offset)
Here, the offset accompanying image fixing will be described. As shown in FIG. 5, during the fixing operation as described above, an offset phenomenon occurs in which the thermoplastic resin (polyester resin) on the surface of the recording material oozes slightly around the recording material and adheres to the fixing belt 114. There is a case. This is because the recording material P is heated and pressurized in the fixing nip portion N, and the thermoplastic resin on the surface of the recording material is melted and spreads around.

  As shown in FIG. 5B, the polyester resin that protrudes from the periphery of the recording material P is offset onto the fixing belt. Then, if the next recording material P is placed on the offset polyester resin around the fixing belt 114, the polyester resin may adhere to the recording material P. As a result, the next image of the recording material P is damaged.

  Therefore, the recording material P is disposed at a predetermined position (contact area of the fixing belt 114 with the recording material P) with respect to the fixing belt 114 for each size of the recording material P. Specifically, as shown in FIG. 6 (a), positions (predetermined positions) X1 to X3 on which a large size (A4 size) recording material P is pasted and a small size (postcard size) recording material P are pasted. A position (predetermined position) X4 was provided.

  The predetermined positions X1 to X4 are positioned in the recording material conveyance direction (arrow X direction) and the recording material width direction (arrow Y direction) orthogonal to the conveyance direction.

  As shown in FIGS. 2 and 8, positioning of the recording material in the conveyance direction (arrow X direction) is performed by detecting a registration sensor 80, a belt sensor 161, a registration roller 163, a recording material size setting unit 164, and a control unit. (CPU).

  The registration sensor 80 detects the leading edge of the recording material P conveyed to the belt fixing device 110 and detects the timing for controlling the amount of abutment (loop amount) against the registration roller 163. The belt sensor 161 detects a mark (not shown) of the fixing belt 114 and detects the phase of the fixing belt 114.

  The positions X1 to X3 where the large size recording material P is pasted and the position X4 where the small size recording material P is pasted are determined based on the mark of the fixing belt 114. The marks on the fixing belt 114 may be provided with different marks at positions X1 to X3 where the large size recording material P is pasted and positions X4 where the small size recording material P is pasted. The fixing belt 114 may have only one mark, and the positions X1 to X4 to be pasted may be determined depending on the distance from the mark (home position mark).

  The registration roller 163 is arranged on the upstream side of the belt fixing device 110 in the conveyance direction, and waits for a predetermined time for the recording material P detected by the registration sensor 80 and fixes the recording material P in accordance with the timing detected by the belt sensor 161. Transport to the nip N.

  As shown in FIG. 8, the size setting unit 164 of the recording material P sets the size of the recording material P conveyed to the belt fixing device 110 by manual or automatic detection (S1). The CPU also receives a signal from the registration sensor 80 and determines whether or not the recording material P is waiting on the registration roller 163 (S2). Whether or not the recording material P is waiting is determined by whether or not a predetermined time has elapsed since the registration sensor 80 detected the leading edge of the recording material P.

  When the recording material P is waiting, the CPU receives a signal from the size setting unit 164 and determines the size of the recording material P (S3). If the recording material P is not waiting, it waits until it is determined that it is waiting.

  When the recording material is a large size, the registration roller 163 is rotated in accordance with the timing detected by the belt sensor 161, and the recording material P is placed on one of the positions X1 to X3 where the large size is applied (S4). ). On the other hand, when the recording material is a small size, the registration roller 163 is rotated in accordance with the timing detected by the belt sensor 161, and the recording material P is placed at the position X4 where the small size is applied (S5).

  On the other hand, as shown in FIG. 7, the recording material P is positioned in the width direction (arrow Y direction) by guide members 81a and 81b that guide the conveyance of the recording material. The guide member 81a is in contact with both ends in the width direction of the large-sized recording material, and positions and conveys the large-sized recording material P with respect to the center. The guide member 81b is in contact with both ends in the width direction of the small-sized recording material P, and positions and conveys the small-sized recording material P with reference to the center.

  The positions of the guide members 81a and 81b are preferably in front of the belt fixing device 110 (upstream in the conveying direction) from the positioning accuracy in the width direction (arrow Y direction) of the recording material. Note that the guide members 81a and 81b may be based on one side. In order to increase the accuracy of the image transfer position, the guide members 81a and 81b may be provided in front of the secondary transfer roller 55 (upstream in the transport direction). In addition, guide members 81 a and 81 b may be provided both in front of the belt fixing device 110 and in front of the secondary transfer roller 55.

  With the above operation and configuration, as shown in FIG. 6A, when the recording material P is a large size, the recording material P is accurately placed on one of the positions X1 to X3 where the large size is pasted on the belt. Is small, it is placed on the belt at a position X4 where the small size is attached with high accuracy.

  As a result, the position where the recording material P is affixed for each size on the fixing belt 114 is specified. Then, as shown in FIG. 6B, the polyester resins Y1 to Y4 that protrude from the recording material P are outside the range of the recording material P, and the recording material P that is conveyed next is the protruding polyester resin Y1 to Y1. It is placed at the attachment positions X1 to X4 inside Y4. Therefore, it is possible to suppress the protruding polyester resins Y1 to Y4 from adhering to the next recording material (in particular, the surface on which the image of the recording material is recorded), and to prevent damage to the image of the next recording material P. . That is, it is possible to suppress the resin protruding from the small-sized recording material P from adhering to the inside of the next large-sized recording material P and causing image defects.

  In the present embodiment, the size of the recording material P having A4 or postcard size has been described. However, other sizes such as B4 may be used. Further, the types of sizes are not limited to two types, and recording materials P having a plurality of types of sizes can be used. At this time, a predetermined position with respect to the fixing belt 114 where the recording material P is arranged for each size may be set.

  Thereby, even when the recording material P having a different size is heated and fixed, it is possible to prevent the resin protruding from the recording material P from adhering to the inside of the next recording material P and causing an image defect.

  In the above-described embodiment, the image heating apparatus detachably attached to the image forming apparatus main body is illustrated as the image heating apparatus including the endless endless belt. However, the present invention is not limited to this. Absent. For example, the image forming apparatus may be an image heating apparatus integrally provided, and the same effect can be obtained by applying the present invention to the image heating apparatus.

  In the embodiment described above, as the image forming apparatus, as shown in FIG. 1, a plurality of developing devices are supported by a rotating member, and the rotating member is rotated and moved so that a predetermined developing device is used. Although an apparatus was illustrated, it is not limited to this. For example, as shown in FIG. 10, a tandem type image forming apparatus using a plurality of developing devices in parallel may be used. Further, as shown in FIGS. 1 and 10, an intermediate transfer member is used, toner images of necessary colors are sequentially transferred onto the intermediate transfer member, and the toner image carried on the intermediate transfer member is transferred to the recording material P. However, the present invention is not limited to an image forming apparatus that performs batch transfer. For example, an image forming apparatus that uses a recording material carrier and sequentially superimposes and transfers toner images of necessary colors on the recording material P carried on the recording material carrier. Further, the printer is exemplified as the image forming apparatus. However, the present invention is not limited to this. For example, other image forming apparatuses such as a copying machine and a facsimile machine, or a multifunction machine combining these functions, etc. Other image forming apparatuses may be used. The same effect can be obtained by applying the present invention to an image heating apparatus having an endless endless belt used in these image forming apparatuses.

  Further, the hue and number of the developer contained in the developing device are not limited to this, and the hue having a combination with different brightness is not limited to magenta or cyan.

  In addition, the dimensions, materials, shapes, and relative positions of the components of the image forming apparatus described above are not intended to limit the scope of the present invention to those unless otherwise specified. Absent.

1 is a schematic configuration diagram illustrating an example of an image forming apparatus. It is a schematic cross-sectional view of a belt fixing device. FIG. 3A is a cross-sectional view of a recording material showing a fixing state of toner after being fixed by a first image heating apparatus. FIG. 6B is a cross-sectional view of the recording material showing a fixing state of the toner after being fixed by the second image heating apparatus. It is a schematic cross-sectional view of a belt fixing device for explaining separation of a recording material. It is explanatory drawing of the offset accompanying image fixing. It is an upper view of the endless belt showing the position where the recording material is pasted. FIG. 2 is a block diagram of a system that performs positioning in the conveyance direction of a recording material. 6 is a flowchart for positioning a recording material in a conveyance direction. It is a block diagram of a guide member. It is a schematic block diagram which shows the other example of an image forming apparatus. It is a top view of a fixing belt for explaining a conventional image defect.

Explanation of symbols

A: Printer unit, B: Reader unit, D: Document, N: Fixing nip unit, P: Recording material, X: Position, Y: Resin, 1: Image carrier, 2 ... Primary charger, 3 ... Laser exposure optics 3a ... polygon mirror 3c ... reflecting mirror 4 ... developer 4A ... rotary 5 ... intermediate transfer belt 6 ... cleaning device 9 ... heat roller fixing device 10 ... image forming device 11-13 ... feed Feed cassette, 14-16 ... feed roller, 17-19 ... conveyance roller, 20 ... registration roller, 21 ... conveyance belt, 22,23 ... roller, 24 ... discharge roller, 25 ... double-sided conveyance path, 26 ... manual feed tray, DESCRIPTION OF SYMBOLS 27 ... Feed roller, 28 ... Conveyance path, 29 ... Reverse pass, 30 ... Reverse roller, 31 ... Original plate glass, 34-36 ... Reflection mirror, 37, 3b ... Lens, 38 ... Sensor, 41-46 ... Developer 50 ... Primary transfer 51, drive roller, 52 ... tension roller, 53 ... secondary transfer counter roller, 54 ... tension roller, 55 ... secondary transfer roller, 57 ... detection sensor, 61-66 ... toner storage unit, 80 ... registration sensor 81 ... Guide member, 81a ... Guide member, 81b ... Guide member, 100 ... Optional unit, 101 ... Switching guide, 102, 103 ... Discharge tray, 104-106 ... Roller pair, 110 ... Belt fixing device (for image heating device) 111) fixing roller, 112 ... separation roller, 114 ... fixing belt (corresponding to endless belt), 116 ... cooling fan, 116a ... fin, 117 ... halogen lamp, 161 ... belt sensor, 163 ... registration roller, 164 ... Size setting section

Claims (3)

An endless belt for heating a toner image formed on a recording material provided with a resin layer; a heating unit for heating the belt; and a cooling unit for cooling the heated recording material that moves with the belt before separation. In the image heating device,
An image heating apparatus, wherein a contact area with a recording material having a belt resin layer is set for each size of the recording material.
2. The image heating apparatus according to claim 1, wherein the belt softens the resin layer of the recording material together with the toner image.
  An image forming unit that forms a toner image on a recording material, the image heating device according to claim 1, and a control unit that controls a timing of conveying the recording material toward the belt. An image forming apparatus.

Images