JP6094162B2 - Fixing apparatus and image forming apparatus - Google Patents

Fixing apparatus and image forming apparatus Download PDF

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Publication number
JP6094162B2
JP6094162B2 JP2012250828A JP2012250828A JP6094162B2 JP 6094162 B2 JP6094162 B2 JP 6094162B2 JP 2012250828 A JP2012250828 A JP 2012250828A JP 2012250828 A JP2012250828 A JP 2012250828A JP 6094162 B2 JP6094162 B2 JP 6094162B2
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fixing device
pressure
recording medium
pressure roller
heat
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JP2014098817A (en
Inventor
智彦 藤井
智彦 藤井
南野 茂夫
茂夫 南野
裕 内藤
裕 内藤
豊田 稔
稔 豊田
藤原 仁
仁 藤原
知哉 足立
知哉 足立
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株式会社リコー
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  The present invention relates to a fixing device for fixing an image on a recording medium and an image forming apparatus including the fixing device, and more particularly, to a fixing device and a fixing device mounted on an image forming apparatus such as a printer, a facsimile machine, or a copying machine. The present invention relates to an image forming apparatus.

  Conventionally, a heat roller fixing device is known as a fixing device used in an image forming apparatus such as a printer, a facsimile machine, or a copying machine. In the heat roller fixing device, a heat source such as a halogen heater is provided inside, and in the contact nip portion (fixing nip portion) of two rotating bodies (fixing roller and pressure roller) that are pressed against each other and rotated while being heated, The transfer material on which the contact toner image is placed is passed through, where the toner image is melted and fixed on the transfer material.

  On the other hand, in recent years, the demand for energy saving and shortening of the wait time has been increased. By adopting a heating device using an endless belt member such as a belt or thin film instead of a heating roller, the low heat capacity of the fixing device In addition, the so-called on-demand type fixing device has been widely adopted, which has improved the heat transfer efficiency to the recording medium and greatly shortened the waiting time required for heating (warm-up time and first print time). Yes.

  This type of fixing device moves while the heating member is in contact with the inner peripheral surface of the belt member, and the heating member is pressed against the rotating body via the belt member, thereby forming a nip portion between the belt member and the rotating body. In this fixing method, the recording medium is conveyed to the nip portion to fix the toner image on the recording medium.

  Such a fixing device is already known to have a system in which a grip member made of an elastic layer is provided at the end of a rotating body outside a region where a recording medium is conveyed, and the belt member is rotated by contacting the belt member. Yes.

  For example, Patent Document 1 discloses a technique in which a tube layer having releasability is provided in a region where a recording material is conveyed among pressure rollers, and a silicone rubber layer having a large frictional force is provided at an end portion. Yes. This technique can satisfy both the slip prevention effect of the recording material and the toner contamination prevention of the pressure roller.

  However, in such a conventional fixing device, a groove shape is formed in the circumferential direction of the roller at the joint between the grip portion formed of the elastic layer of the rotating body and the recording medium coated with the heat-resistant sheet in the manufacturing process. It is formed.

  For this reason, in such a fixing device, the heat of the surface of the belt member is not taken away by the rotator at the groove during heating rotation, and the temperature of the surface of the belt member facing the groove rapidly increases. As a result, in such a fixing device, when a belt member with low thermal conductivity is used, there is a problem that the surface of the belt member is deteriorated due to a rapid temperature rise on the surface of the belt member facing the groove. . Further, the fixing device has a problem that the cost of the belt member increases when a metal belt member having high thermal conductivity is used.

  The present invention has been made to solve the above-described problems, and ensures a grip force between the pressurizing rotating body and the belt member, and reduces the deterioration of the surface of the belt member due to a sudden temperature rise. It is an object to provide a fixing device that can be prevented at a cost.

In order to achieve the above object, a fixing device according to the present invention is a fixing device including a belt member having a heat source therein and bonded at both ends, and a pressure rotating body that rotates in contact with the belt member. The pressure rotator is a pressure unit in which a heat-resistant layer is formed on the surface of the elastic layer, and when the recording medium is transported , the recording medium is transported through the recording medium when the recording medium is transported. A pressure part that contacts the belt member, and a contact part that the elastic layer exposes, and a contact part that contacts the belt member in a region outside the longitudinal direction of the region where the recording medium is conveyed, A groove portion that is a notch with respect to the pressure rotator formed on a boundary line between the pressure portion and the contact portion, and the groove portion is perpendicular to the longitudinal direction of the pressure rotator. except for being formed in a circumferential direction of the pressure rotating body It is characterized in.

  According to the present invention, it is possible to provide a fixing device that can secure a grip force between a pressure rotating body and a belt member and prevent deterioration of the surface of the belt member due to a rapid temperature rise at a low cost.

1 is a schematic perspective view of a tandem type color printer including a fixing device according to a first embodiment of the present invention. 1 is a schematic cross-sectional view of a fixing device according to an embodiment of the present invention. 1 is a schematic front view of a fixing device according to an embodiment of the present invention. (A) is a schematic front view of the belt member and pressurization rotary body which concerns on embodiment of this invention, (b) is a schematic front view which shows the state which the pressurization rotary body rotated from the state of (a). . It is a schematic front view of the edge part of the pressurization rotary body which concerns on embodiment of this invention. It is a schematic front view which shows the modification of the pressurization rotary body which concerns on embodiment of this invention.

Embodiments of the present invention will be described below with reference to the drawings.
1 to 5 are diagrams showing an embodiment of a fixing device and an image forming apparatus according to the present invention, and show an example in which the image forming apparatus is applied to a tandem type color printer.

  FIG. 1 is a diagram illustrating a configuration of an image forming apparatus. In FIG. 1, an image forming apparatus 1 includes image forming units 4Y, 4M, 4C, and 4K corresponding to respective colors (yellow (Y), magenta (M), cyan (C), and black (K)), and a sheet feeding unit. 12, a fixing device 20, an intermediate transfer unit 85, and a bottle container 101.

  The bottle storage unit 101 is provided above the image forming apparatus 1, and in the bottle storage unit 101, four toner bottles 102Y, 102M, 102C, and 102K corresponding to the respective colors are detachably installed.

  The intermediate transfer unit 85 is provided below the bottle storage unit 101, and includes an intermediate transfer belt 78, four primary transfer bias rollers 79Y, 79M, 79C, and 79K, an intermediate transfer cleaning unit 80, and a secondary transfer. And a backup roller 82. The intermediate transfer unit 85 includes a cleaning backup roller 83 and a tension roller 84.

  The image forming units 4Y, 4M, 4C, and 4K are provided side by side so as to face the intermediate transfer belt 78. The image forming units 4Y, 4M, 4C, and 4K are respectively photosensitive drums 5Y, 5M, 5C, and 5K, charging units 75Y, 75M, 75C, and 75K, developing units 76Y, 76M, 76C, and 76K, and a cleaning unit 77Y. , 77M, 77C, 77K, and a static elimination unit (not shown).

  The photosensitive drums 5Y, 5M, 5C, and 5K are rotationally driven in a clockwise direction in FIG. 1 by a drive motor (not shown). On the photosensitive drums 5Y, 5M, 5C, and 5K, an image forming process including a charging process, an exposure process, a developing process, a transfer process, and a cleaning process is executed.

  First, in the charging step, the photosensitive drums 5Y, 5M, 5C, and 5K are uniformly charged on the photosensitive drums 5Y, 5M, 5C, and 5K at the positions of the charging units 75Y, 75M, 75C, and 75K.

  Next, in the exposure process, the photosensitive drums 5Y, 5M, 5C, and 5K are irradiated with the laser beams Ly, Lm, Lc, and Lk emitted from the exposure unit 3, and exposed to the photosensitive drums 5Y, 5M, 5C, and so on. An electrostatic latent image corresponding to each color is formed on 5K.

  Next, in the developing process, the photosensitive drums 5Y, 5M, 5C, and 5K are arranged so that the electrostatic latent images on the photosensitive drums 5Y, 5M, 5C, and 5K are at positions facing the developing devices 76Y, 76M, 76C, and 76K. Developed. As a result, toner images of respective colors are formed on the photosensitive drums 5Y, 5M, 5C, and 5K.

  Next, in the primary transfer step, the photosensitive drums 5Y, 5M, 5C, and 5K are positioned at positions facing the intermediate transfer belt 78 and the first transfer bias rollers 79Y, 79M, 79C, and 79K, and the photosensitive drums 5Y, 5M, The toner images on 5C and 5K are transferred onto the intermediate transfer belt 78. At this time, a small amount of untransferred toner remains on the photosensitive drums 5Y, 5M, 5C, and 5K.

  Next, in the cleaning process, the photosensitive drums 5Y, 5M, 5C, and 5K are untransferred toner remaining on the photosensitive drums 5Y, 5M, 5C, and 5K at positions facing the cleaning units 77Y, 77M, 77C, and 77K. Is mechanically collected by the cleaning blades of the cleaning units 77Y, 77M, 77C, and 77K.

  Then, the residual potentials on the photosensitive drums 5Y, 5M, 5C, and 5K are removed from the photosensitive drums 5Y, 5M, 5C, and 5K at positions facing the neutralization unit.

  Through the above image forming process, a toner image of each color is formed on the intermediate transfer belt 78.

  The intermediate transfer belt 78 is supported in a tensioned state by a secondary transfer backup roller 82, a cleaning backup roller 83, and a tension roller 84.

  The four primary transfer bias rollers 79Y, 79M, 79C, and 79K sandwich the intermediate transfer belt 78 with the photosensitive drums 5Y, 5M, 5C, and 5K, respectively, thereby forming primary transfer nips. Further, a transfer bias reverse to the polarity of the toner is applied to the primary transfer bias rollers 79Y, 79M, 79C, and 79K.

  The intermediate transfer belt 78 is moved in the direction of the arrow in FIG. 1 by the rotational drive of the secondary transfer backup roller 82, and sequentially passes through the primary transfer nips of the primary transfer bias rollers 79Y, 79M, 79C, and 79K.

  As a result, the toner images of the respective colors on the photosensitive drums 5Y, 5M, 5C, and 5K are primarily transferred while being superimposed on the intermediate transfer belt 78. Thereafter, the intermediate transfer belt 78 onto which the toner images of the respective colors are transferred in an overlapping manner reaches a position facing the secondary transfer roller 89.

  The four-color toner images formed on the intermediate transfer belt 78 are conveyed to the position of the secondary transfer nip formed by sandwiching the intermediate transfer belt 78 between the secondary transfer backup roller 82 and the secondary transfer roller 89. Is transferred onto the recorded recording medium P.

  Then, the intermediate transfer belt 78 reaches the position of the intermediate transfer cleaning unit 80, and untransferred toner that has not been transferred to the recording medium P remaining on the intermediate transfer belt 78 is collected.

  The paper feeding unit 12 is provided below the image forming apparatus 1, and a plurality of recording media P such as transfer paper are stored in the paper feeding unit 12 in a stacked manner.

  Next, a process for conveying the recording medium P from the paper supply unit 12 will be described.

  First, the uppermost recording medium P stored in the paper supply unit 12 is directed between the registration rollers 98a and 98b by the paper supply roller 97 being rotated counterclockwise in FIG. Are transported.

  Next, the recording medium P temporarily stops at the position of the roller nip provided between the registration rollers 98a and 98b.

  The recording medium P is conveyed toward the secondary transfer nip when the registration rollers 98a and 98b are rotationally driven in accordance with the timing when the toner image on the intermediate transfer belt 78 comes. As a result, the toner image is transferred onto the recording medium P.

  The recording medium P on which the toner image is transferred at the position of the secondary transfer nip is conveyed to the position of the fixing device 20. The toner image transferred onto the recording medium P is fixed on the recording medium P by heat and pressure by the fixing belt 21 serving as a belt member and the pressure roller 31 serving as a pressure rotating body, whereby a color image is formed. It is fixed on the recording medium P.

The recording medium P on which the color image is fixed is discharged out of the image forming apparatus 1 through the paper discharge rollers 99a and 99b, and is stacked on the stack unit 100 as an output image.
Thus, a series of image forming processes in the image forming apparatus 1 is completed.

FIG. 2 is a diagram illustrating the configuration of the fixing device 20.
As shown in FIG. 2, the fixing device 20 includes a fixing belt 21, a heating member 22, a reinforcing member 23, a heater 25 as a heat source, a fixing member 26, a pressure roller 31, a temperature sensor 40, And a pressurizing mechanism 50. The fixing device 20 includes a first stay (not shown), a second stay (not shown), and a sheet-like member (not shown) on the inner peripheral surface side of the fixing belt 21.

  The fixing belt 21 is a thin and flexible endless belt, and rotates in the direction of the arrow in FIG. Here, endless means a state in which there is no joint between the two ends of the belt.

The fixing belt 21 has a base material layer, an elastic layer, and a release layer sequentially laminated from the inner peripheral surface side, and the total thickness is set to 1 mm or less.
The base material layer of the fixing belt 21 has a layer thickness of 30 to 100 μm and is formed of a metal material such as nickel or stainless steel or a resin material such as polyimide. This is an exemplification, and the present invention is not limited to this.

  The elastic layer of the fixing belt 21 has a layer thickness of 100 to 300 μm and is formed of a rubber material such as silicone rubber, foamable silicone rubber, or fluororubber. This is an exemplification, and the present invention is not limited to this.

  By providing the elastic layer, when the color image is fixed on the recording medium P at the nip portion formed between the fixing belt 21 and the pressure roller 31, minute irregularities on the surface of the fixing belt 21 are not formed. Then, heat is uniformly transmitted to the toner image T on the recording medium P.

  As a result, the fixing device 20 can suppress the occurrence of a cocoon skin image on the recording medium P. Here, the cocoon skin image means an image in which a number of minute irregularities are formed on the surface.

  The release layer of the fixing belt 21 has a layer thickness of 10 to 50 μm, and includes PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), PTFE (polytetrafluoroethylene), polyimide, polyetherimide, PES ( Polyether sulfide) and the like. This is an exemplification, and the present invention is not limited to this.

  By providing the release layer, the fixing belt 21 is secured with respect to the toner image T on the recording medium P. The diameter of the fixing belt 21 is set to be 15 to 120 mm. In the present embodiment, the diameter of the fixing belt 21 is set to about 30 mm. This is merely an example, and the present invention is not limited to this. Moreover, the mold release means that the bonded objects are peeled off, and the mold release property means the ease of peeling between the objects.

  The fixing member 26 is fixed so as to contact the inner peripheral surface of the fixing belt 21 and to move the fixing belt 21. Further, the fixing member 26 is pressed against the pressure roller 31 via the fixing belt 21 to form a nip portion where the recording medium P is conveyed.

  The heating member 22 is a pipe-like member having both ends in the width direction fixedly supported by the side plates 42 and 43 of the fixing device 20 and a wall thickness of 0.2 mm or less. This is an exemplification, and the present invention is not limited to this. As a material of the heating member 22, a metal having thermal conductivity such as aluminum, iron, stainless steel or the like can be used.

  By setting the thickness of the heating member 22 to 0.2 mm or less, the fixing device 20 can improve the heating efficiency of the fixing belt 21. The heating member 22 is formed so as to be close to or in contact with the inner peripheral surface of the fixing belt 21 at a position excluding the nip portion. At the position of the nip portion, a concave shape is formed inside and an opening is formed. A recess is provided.

  In addition, the fixing device 20 includes fluorine grease or silicone between the heating member 22 and the fixing belt 21 so as to reduce wear of the fixing belt 21 that occurs when the heating member 22 and the fixing belt 21 move in contact with each other. Lubricant such as oil is applied.

  The heating member 22 is heated by radiant heat and radiant light (hereinafter simply referred to as “radiant heat”) of the heater 25 to heat the fixing belt 21. That is, the fixing device 20 is configured such that the heating member 22 is directly heated by the heater 25 and the fixing belt 21 is indirectly heated by the heater 25 via the heating member 22.

  That is, in the fixing device 20, the heating member 22 entirely heats the fixing belt 21 at a position excluding the nip portion, and heat is applied to the toner image T on the recording medium P from the surface of the heated fixing belt 21. It has become.

  The heater 25 is constituted by a halogen heater or a carbon heater, and both ends thereof are fixed to the side plates 42 and 43 of the fixing device 20. The output control of the heater 25 is performed based on the result of detecting the surface temperature of the fixing belt 21 by the temperature sensor 40 facing the surface of the fixing belt 21.

  Further, the fixing device 20 can set the fixing temperature of the fixing belt 21 for fixing the color image on the recording medium P to a desired temperature by such output control of the heater 25. Here, the temperature sensor 40 is configured by a thermistor or the like.

  The reinforcing member 23 reinforces and supports the fixing member 26 that forms the nip portion. The reinforcing member 23 is formed so that the length in the width direction is equal to that of the fixing member 26, and is formed on the inner peripheral surface side of the fixing belt 21. Is provided.

  The reinforcing member 23 comes into contact with the pressure roller 31 via the fixing member 26 and the fixing belt 21, thereby preventing a problem that the fixing member 26 is greatly deformed by the pressure applied by the pressure roller 31 in the nip portion. doing.

  The pressure roller 31 is provided so as to contact the outer peripheral surface of the fixing belt 21 at the position of the nip portion, and has a diameter of about 20 to 40 mm and is different from the diameter of the fixing belt 21. This is an exemplification, and the present invention is not limited to this.

  The pressure roller 31 has an elastic layer 33 formed on a core metal 32 having a heat-resistant hollow structure, a heat-resistant layer 34 is formed on the surface of the elastic layer 33, and a heat-resistant sheet portion 31a as a pressure portion on the surface. And the grip part 31b as a contact part and the groove part 31c are provided.

  The pressure roller 31 is provided with a gear 35 that meshes with a drive gear of a drive mechanism (not shown), and the pressure roller 31 is rotationally driven in the direction of the arrow in FIG. As shown in FIG. 3, both ends of the pressure roller 31 in the width direction are rotatably supported by side plates 42 and 43 of the fixing device 20 via bearings 42a and 43a.

  The elastic layer 33 is formed of a material such as foamable silicone rubber, silicone rubber, or fluororubber. The heat-resistant layer 34 is provided on the surface layer of the elastic layer 33 with a thin wall, and is formed of a material having heat resistance and releasability such as PFA and PTFE. The elastic layer 33 and the heat-resistant layer 34 are integrally formed.

  Further, when the elastic layer 33 is formed of a sponge-like material such as foamable silicone rubber, the applied pressure acting on the nip portion can be reduced, so that the bending that occurs in the fixing member 26 can be reduced. . In this case, the heating efficiency of the fixing belt 21 is improved because the heat of the fixing belt 21 becomes difficult to move to the pressure roller 31 side.

  The fixing device 20 is provided with a pressure mechanism 50 that contacts and separates the pressure roller 31 from the fixing belt 21. The pressure mechanism 50 includes a pressure lever 51 and a pressure spring 52.

  The pressure lever 51 is rotatably supported by the side plate 43 of the fixing device 20 around a support shaft 51a provided on one end side. The central portion of the pressure lever 51 is in contact with a bearing 43 a of the pressure roller 31 that is movably held in an elongated hole formed in the side plate 43 of the fixing device 20. A pressure spring 52 is connected to the other end side of the pressure lever 51.

  With such a configuration, the pressure lever 51 rotates around the support shaft 51a during a normal fixing operation, and the pressure roller 31 presses the fixing belt 21 to form a desired nip portion.

Next, a normal operation of the fixing device 20 configured as described above will be briefly described.
When the power switch of the image forming apparatus 1 is turned on, power is supplied to the heater 25, and the rotational driving of the pressure roller 31 in the direction of the arrow in FIG.

  Thereby, the fixing belt 21 is also driven to rotate in the direction of the arrow in FIG. 2 by the frictional force with the pressure roller 31. Thereafter, the recording medium P is fed from the paper feeding unit 12, and the unfixed toner image T is transferred onto the recording medium P at the position of the secondary transfer roller 89.

  The recording medium P onto which the unfixed toner image T has been transferred is conveyed in the direction of arrow Y10 in FIG. 2 while being guided by a guide plate (not shown), and is pressed between the fixing belt 21 and the pressure roller 31 in a pressed state. It is carried into the nip part.

The surface of the recording medium P is heated by the fixing belt 21 heated by the heater 25 via the heating member 22 and the pressing force of the fixing member 26 reinforced by the reinforcing member 23 and the pressure roller 31. The color image is fixed on the recording medium P.
Thereafter, the recording medium P sent out from the nip portion is conveyed in the direction of arrow Y11, and a series of fixing processes in the fixing device 20 is completed.

4A and 4B are views showing the surface of the pressure roller 31 in a state where the pressure roller 31 is viewed from the front.
As shown in FIG. 4A, the heat resistant sheet portion 31 a of the pressure roller 31 is provided on the heat resistant layer 34. The heat-resistant sheet portion 31 a is provided in an area where the recording medium P is conveyed (hereinafter referred to as “recording medium conveyance area”), and when the recording medium P is conveyed, the heat-resistant sheet portion 31 a is connected to the fixing belt 21 via the recording medium P. Contact.

  As shown in FIG. 4A, the grip portion 31b of the pressure roller 31 is provided in a region outside the longitudinal direction of the recording medium conveyance region (hereinafter referred to as “outside of the recording medium conveyance region”). The grip portion 31b is configured by peeling the heat-resistant layer 34 formed on the surface of the pressure roller 31 and exposing the elastic layer 33, and has a large friction coefficient on the surface.

  That is, the frictional force acting between the fixing belt 21 and the pressure roller 31 is greater in the region where the grip portion 31b and the fixing belt 21 are opposed than in the region where the heat resistant sheet portion 31a and the fixing belt 21 are opposed. It will act strongly.

  In the fixing device 20, when the recording medium P having a small surface friction coefficient is conveyed to the nip portion, the frictional force acting between the fixing belt 21 and the pressure roller 31 is reduced in the recording medium conveyance region.

  However, since the fixing device 20 has a high frictional force acting between the fixing belt 21 and the pressure roller 31 outside the recording medium conveyance area, the gripping force between the two members is ensured. Thereby, the fixing device 20 can prevent the fixing belt 21 and the pressure roller 31 from slipping.

  As shown in FIG. 4A, the groove 31c of the pressure roller 31 is provided between the heat-resistant sheet portion 31a and the grip portion 31b. When the pressure roller 31 is viewed from the front, the pressure roller 31 is provided. It is formed in the circumferential direction with an inclination with respect to the rotation axis.

  For this reason, as shown in FIG. 4B, when the pressure roller 31 rotates, the groove 31c moves in the longitudinal direction of the pressure roller 31 at a position facing the fixing belt 21 following the inclination. .

Further, as described above, the fixing belt 21 and the pressure roller 31 have different diameters.
As a result, the fixing device 20 does not have a region on the surface of the fixing belt 21 that always faces the groove 31c and is not in contact with the pressure roller 31 even if the pressure roller 31 continues to rotate. Deterioration of the fixing belt 21 due to a local temperature rise on the surface of the belt 21 can be prevented.

  As shown in FIG. 4A, the groove 31 c is provided on both sides of the pressure roller 31. In one groove 31c and the other groove 31c, the distance L1 between both grooves in the longitudinal direction of the pressure roller 31 is always larger than the distance in the longitudinal direction of the recording medium conveyance area.

  In addition, the groove shapes of the one groove portion 31c and the other groove portion 31c are configured to be symmetrical with respect to the central axis C orthogonal to the longitudinal direction at the position of the center of the pressure roller 31 in the longitudinal direction. ing.

  As a result, the fixing device 20 can prevent the fixing belt 21 from approaching one end side due to contact with the pressure roller 31.

FIG. 5 is a diagram for explaining in detail the shape of the groove 31c of the pressure roller 31 and the shape of the grip 31b.
As shown in FIG. 5, the groove width W as the width dimension represents the width dimension of the groove portion 31c. Further, the groove depth D as the depth dimension represents the depth dimension of the groove portion 31c.

  The groove portion 31c is configured in a shape in which the groove width W is larger than the groove depth D. As a result, the pressure roller 31 is close to the fixing belt 21 in the groove 31c, so that the heat of the fixing belt 21 is easily transmitted to the pressure roller 31.

  Further, when the pressure roller 31 is viewed from the front, the groove portion 31 c is a separation distance in the longitudinal direction between a point contacting the grip portion 31 b on the upper surface of the pressure roller 31 and a point contacting the grip portion 31 b on the lower surface of the pressure roller 31. The separation distance L2 is larger than the groove width W.

  As a result, the fixing device 20 does not have a region on the surface of the fixing belt 21 that always faces the groove 31c and is not in contact with the pressure roller 31 even if the pressure roller 31 continues to rotate. Deterioration of the fixing belt 21 due to a local temperature rise on the surface of the belt 21 can be prevented.

  The grip portion 31 b is provided with a sufficient distance L <b> 3 so that the longitudinal distance of the pressure roller 31 can secure a grip force necessary to prevent a slip generated between the fixing belt 21 and the pressure roller 31. ing.

  In the present embodiment, the grip portion 31b is configured such that L3 is 10 mm or more. This is an exemplification, and the present invention is not limited to this.

  As a result, the fixing device 20 can secure a grip force that can prevent a slip generated between the fixing belt 21 and the pressure roller 31 due to contact with the fixing belt 21 at the grip portion 31b. .

  As described above, the fixing device 20 according to the present embodiment includes the fixing belt 21 having the heater 25 therein and bonded at both ends, and the pressure roller 31 that rotates in contact with the fixing belt 21. It is configured.

  The pressure roller 31 includes a heat resistant sheet portion 31a that contacts the fixing belt 21 via the recording medium P in the recording medium conveyance area when the recording medium P is conveyed, and a fixing belt outside the recording medium conveyance area. 21 is provided between the grip portion 31b that is in contact with the heat resistance 21 and the heat resistant sheet portion 31a and the grip portion 31b, and in the circumferential direction of the pressure roller 31 except for the direction orthogonal to the longitudinal direction of the pressure roller 31. It is comprised so that the groove part 31c formed may be provided.

  For this reason, the fixing device 20 does not have a region on the surface of the fixing belt 21 that always faces the groove 31c and is not in contact with the pressure roller 31 even if the pressure roller 31 continues to rotate. Deterioration of the fixing belt 21 due to a local temperature rise on the surface of the belt 21 can be prevented.

  Further, the fixing device 20 can secure a grip force that can prevent a slip generated between the fixing belt 21 and the pressure roller 31 by contact with the fixing belt 21 at the grip portion 31b.

  In the fixing device 20 according to the present embodiment, the pressure roller 31 includes an elastic layer 33 having elasticity and a heat-resistant layer 34 provided on the surface of the elastic layer 33 and having heat resistance. The elastic layer 33 and the heat-resistant layer 34 are formed integrally with the pressure roller 31, and the grip portion 31b is provided by removing the heat-resistant layer 34.

  Therefore, in the fixing device 20, the heat-resistant sheet portion 31a and the grip portion 31b are provided without increasing the number of parts, and the grip between the fixing belt 21 and the pressure roller 31 in the grip portion 31b is reduced. It can be secured at a cost.

  The fixing device 20 according to the present embodiment is configured such that the fixing belt 21 and the pressure roller 31 have different diameters.

  For this reason, the fixing device 20 does not have a region on the surface of the fixing belt 21 that always faces the groove 31c and is not in contact with the pressure roller 31 even if the pressure roller 31 continues to rotate. Deterioration of the fixing belt 21 due to a local temperature rise on the surface of the belt 21 can be prevented.

  Further, in the fixing device 20 according to the present embodiment, the groove portion 31c has a distance L1 in the longitudinal direction of the pressure roller 31 between the one groove portion 31c and the other groove portion 31c. It is configured to be larger than the size in the direction.

  For this reason, since the groove portion 31c does not exist in the recording medium conveyance region, the fixing device 20 faces the groove portion 31c when the toner image T is fixed on the recording medium P, and heating and pressurization are insufficient. It is possible to prevent the toner image T from being insufficiently fixed.

  Further, in the fixing device 20 according to the present embodiment, the groove portion 31 c is configured such that the groove width W is larger than the groove depth D.

  Therefore, in the fixing device 20, since the pressure roller 31 is separated from the fixing belt 21 in the groove portion 31 c, the heat of the fixing belt 21 is easily transmitted to the pressure roller 31.

  In the fixing device 20 according to the present embodiment, the length L3 of the grip portion 31b in the longitudinal direction of the pressure roller 31 is in contact with the fixing belt 21 and slip generated between the fixing belt 21 and the pressure roller 31. It is configured to be long enough to prevent

  For this reason, the fixing device 20 can ensure a grip force that can prevent a slip generated between the fixing belt 21 and the pressure roller 31 by contact with the fixing belt 21 at the grip portion 31b. .

  Further, in the fixing device 20 according to the present embodiment, the shape of the one groove portion 31c and the shape of the other groove portion 31c are set to a central axis C that is orthogonal to the longitudinal direction at the position of the center of the pressure roller 31 in the longitudinal direction. It is configured to have a line-symmetric shape.

  For this reason, the fixing device 20 can prevent the fixing belt 21 from approaching one end side due to contact with the pressure roller 31.

  Further, in the fixing device 20 according to the present exemplary embodiment, the groove 31c grips at the point where the groove 31c contacts the grip part 31b on the upper surface of the pressure roller 31 and the lower surface of the pressure roller 31 when the pressure roller 31 is viewed from the front. The separation distance L2 in the longitudinal direction of the pressure roller 31 at the point in contact with the portion 31b is configured to be larger than the groove width W.

  As a result, the fixing device 20 does not have a region on the surface of the fixing belt 21 that always faces the groove 31c and is not in contact with the pressure roller 31 even if the pressure roller 31 continues to rotate. Deterioration of the fixing belt 21 due to a local temperature rise on the surface of the belt 21 can be prevented.

  In the present embodiment, the heater 25 is a halogen heater. However, the heater 25 is not limited to this and may be, for example, an induction heating type heat source.

  Moreover, in this Embodiment, although the cross-sectional shape of the heating member 22 was formed so that it might become substantially circular, you may form so that it may become not only this but a polygon.

  In this embodiment, the pressure roller 31 has only the cored bar 32. However, the present invention is not limited to this, and a heat source such as a halogen heater is provided inside the pressure roller 31. Also good.

  In the present embodiment, the diameter of the fixing belt 21 may be different from the diameter of the pressure roller 31, and may be formed to be smaller than the diameter of the pressure roller 31, for example. In this case, since the curvature of the fixing belt 21 at the nip portion is smaller than the curvature of the pressure roller 31, the recording medium P delivered from the nip portion is easily separated from the fixing belt 21. Further, the diameter of the fixing belt 21 can be formed to be larger than the diameter of the pressure roller 31.

  Here, the fixing device 20 is configured such that the pressure applied by the pressure roller 31 does not act on the heating member 22 regardless of the relationship between the diameter of the fixing belt 21 and the diameter of the pressure roller 31.

  In the present embodiment, the pressure roller 31 is used as the pressure rotator of the fixing device 20, but the present invention is not limited to this, and the pressure roller 31 may be used in a fixing device constituted by a fixing roller.

  In the present embodiment, the elastic layer 33 and the heat-resistant layer 34 of the pressure roller 31 are integrally formed. However, the present invention is not limited to this, and the heat-resistant layer 34 formed as a separate member on the surface of the elastic layer 33. May be adhered.

  Further, in the present embodiment, the groove 31c of the pressure roller 31 is configured in a linear shape. However, the present invention is not limited to this, and the meandering along the circumferential direction of the pressure roller 31 is not limited to this. The shape to do may be sufficient.

  As a result, the fixing device 20 does not have a region on the surface of the fixing belt 21 that always faces the groove 31c and is not in contact with the pressure roller 31 even if the pressure roller 31 continues to rotate. Deterioration of the fixing belt 21 due to a local temperature rise on the surface of the belt 21 can be prevented.

  In this embodiment, the fixing device is applied to a tandem color printer. However, the fixing device may be applied to an image forming apparatus such as a facsimile machine or a copying machine.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 20 Fixing apparatus 21 Fixing belt (belt member)
25 Heater (heat source)
31 Pressure roller (Pressure rotating body)
31a Heat-resistant sheet part (pressurizing part)
31b Grip part (contact part)
31c Groove part 33 Elastic layer 34 Heat-resistant layer C Center axis D Groove depth (depth dimension)
L2 Separation distance (separation dimension)
P Recording medium W Groove width (width dimension)

JP 09-126225 A

Claims (10)

  1. A belt member having a heat source therein and bonded at both ends;
    A fixing device including a pressure rotator rotating in contact with the belt member,
    The pressure rotator is a pressure unit in which a heat-resistant layer is formed on the surface of the elastic layer, and when the recording medium is conveyed , the recording medium is conveyed through the recording medium when the recording medium is conveyed. A pressurizing part that contacts the belt member;
    A contact portion where the elastic layer is exposed, and a contact portion that contacts the belt member in a region outside the longitudinal direction of the region where the recording medium is conveyed;
    A groove portion that is a notch with respect to the pressure rotating body formed on a boundary line between the pressure portion and the contact portion ;
    The groove, the fixing device characterized that you have been formed in the circumferential direction of the pressure rotating body except a direction perpendicular to the longitudinal direction of the pressure rotating body.
  2. The pressure rotator is constituted by an elastic layer having elasticity and a heat-resistant layer having heat resistance provided on the surface of the elastic layer,
    The fixing device according to claim 1, wherein the elastic layer and the heat-resistant layer are formed integrally with the pressure rotating body, and the contact portion is provided by removing the heat-resistant layer.
  3.   The fixing device according to claim 1, wherein the belt member and the pressure rotating body have different diameters.
  4.   The groove portion is characterized in that a distance between one groove portion and the other groove portion in the longitudinal direction of the pressure rotator is larger than a size of a region in which the recording medium is conveyed in the longitudinal direction of the pressure rotator. The fixing device according to any one of claims 1 to 3.
  5.   The fixing device according to claim 1, wherein the groove portion has a width dimension larger than a depth dimension.
  6.   The contact portion has a length in the longitudinal direction of the pressurizing rotator that is sufficient to prevent the slip that occurs between the belt member and the pressurizing rotator when contacting the belt member. The fixing device according to any one of claims 1 to 5, wherein the fixing device is characterized in that:
  7.   The shape of the groove portion is a shape in which the shape of one groove portion and the shape of the other groove portion are axisymmetric with respect to an axis orthogonal to the longitudinal direction at a position in the longitudinal center of the pressure rotating body. The fixing device according to claim 1, wherein
  8. In the state where the pressurizing rotator is viewed from the front, the groove portion is configured to perform the pressurization rotation at a point where the upper surface of the pressurizing rotator is in contact with the contact portion and a lower surface of the pressurizing rotator is in contact with the contact portion. The fixing device according to claim 5 , wherein a separation dimension in a longitudinal direction of the body is larger than the width dimension.
  9.   The fixing device according to claim 1, wherein the groove portion meanders along a circumferential direction of the pressure rotator.
  10.   An image forming apparatus comprising the fixing device according to claim 1.
JP2012250828A 2012-11-15 2012-11-15 Fixing apparatus and image forming apparatus Active JP6094162B2 (en)

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Application Number Priority Date Filing Date Title
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US8005055B2 (en) * 2003-07-23 2011-08-23 Interdigital Technology Corporation Method and apparatus for determining and managing congestion in a wireless communications system

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH075783A (en) * 1993-06-14 1995-01-10 Ricoh Co Ltd The fixing device
JP2001100555A (en) * 1999-09-28 2001-04-13 Seiko Epson Corp Belt type fixing device
JP2003076192A (en) * 2001-09-05 2003-03-14 Canon Inc Heat fixing device
JP4747699B2 (en) * 2005-07-04 2011-08-17 コニカミノルタビジネステクノロジーズ株式会社 Fixing apparatus and image forming apparatus
JP5672540B2 (en) * 2011-01-11 2015-02-18 株式会社リコー Fixing apparatus, image forming apparatus, and method of using fixing apparatus

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