JPH06214481A - Image forming device - Google Patents

Abstract

PURPOSE:To eliminate static electricity charged onto a transfer paper without providing a destaticization brush. CONSTITUTION:A surface coming into contact with the transfer paper P of the fixing roller 12 of a fixing device 11 is composed of a surface coating layer 15 incorporating a self discharge type static neutralizer in a surface coating material and simultaneously, the outer peripheral part of a pressurizing roller 13 is covered with a surface coating tube incorporating the static neutralizer, as well. When the electrified transfer paper P passes between these rollers 12 and 13, the electrified transfer paper P comes into contact with the static neutralizer, so that the charged static electricity is eliminated with the charge of the polarity opposite to that of an electrostatic charge. Moreover, when the surface coating layer does not exist on each roller. it is desirable that the static neutralizer is incorporated in the rubber material of the roller. Further, the static neutralizer can be incorporated in a carrying guide member guiding the transfer paper and made of an insulating material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a facsimile, a printer or the like for forming an image on a fed sheet-shaped transfer sheet.

[0002]

2. Description of the Related Art In an electrophotographic image forming apparatus,
In the process of image formation, the transfer paper receives corona charge, the charged toner is transferred to it, and it is transported while rubbing against the insulator during the transport process, so that static electricity is charged there. easy.

In general, transfer paper charged with static electricity is likely to be adsorbed on an insulating material. Therefore, if the transfer paper is discharged as it is, the transfer paper P becomes the main body of the apparatus as shown in FIGS. 13 (a) and 13 (b), for example. When the paper is discharged from 1 to the discharge tray 2,
The front end side of the next transfer paper P may be adsorbed to the rear end side of the transfer paper P discharged first, and the transfer paper P discharged first may be pushed out on the paper discharge tray 2 and the stack position may be displaced. is there.

Further, as shown in FIGS. 14A and 14B, when the front end of the transfer paper P is curled up and curled up, it is adsorbed to the rear end side of the previously discharged transfer paper P. In the same way, a normal stack cannot be created. Therefore, for example, in the case of the image forming apparatus described in Japanese Patent Laid-Open No. 61-291365, a static electricity removing member is provided on the sheet-shaped sheet conveying path, and the leading end of the sheet is conveyed to the conveying path. The contact is made slightly so as not to give a large resistance, and the static electricity on the paper when charged is removed.

Also, in the other image forming apparatuses, the conductive static elimination brush 5 is used, for example, in FIGS.
As shown in FIG. 6, it is often provided in the paper discharge port 3 of the apparatus main body 1 or the like, and the tip thereof is slightly contacted with the transfer paper P to eliminate the charge.

[0006]

However, the provision of such a static electricity removing member such as a brush exclusively for static elimination would increase the cost accordingly. In addition, such a conductive anti-static brush removes static electricity by dropping the static electricity on the transfer paper to the ground via the brush, while the device is a metal component used in recent years due to its weight reduction. Since it is often replaced by an insulating member such as plastic, the paper discharge port 3 shown in FIG.
When the side plate 4 provided in the vicinity of is made of sheet metal, the base portion 5a formed of the conductive member of the static elimination brush 5 may be fixed to the side plate 4 by tightening with screws 6 as shown in the figure. However, there is a problem when each component including the side plate 4 near the paper discharge port 3 is formed of an insulating member such as plastic.

That is, in such a case, the disposition position of the static elimination brush 5 is changed to a position where a member made of sheet metal is provided, or as shown in FIG. Since it was necessary to attach one end side of the grounding cord 7 and connect the other end side to the body side plate 8 made of sheet metal or the like, the apparatus may be complicated and the assembling property may be deteriorated.

The present invention has been made in view of the above problems, and it is possible to eliminate static electricity from a charged transfer paper without providing a dedicated static elimination brush or the like for eliminating static electricity. The purpose is to

[0009]

In order to achieve the above object, the present invention provides an image forming apparatus as described above,
When at least one of the fixing member and the pressure member, which comes into contact with the transfer paper, comes into contact with a member charged with static electricity, the member is neutralized by neutralizing the member by removing the charge with a charge having a polarity opposite to that of the charged charge. It is formed by a surface coating material mixed with a discharge type static neutralizer.

Further, there is provided a fixing device having a fixing member for sandwiching and fixing the transfer paper on which the toner image is transferred by heating and a pressure member, and at least a portion contacting the transfer paper is formed of a rubber material. In the image forming apparatus provided with the self-discharge type electrostatic neutralization, when the rubber member is contacted with a member charged with static electricity, the member is neutralized by neutralizing the member with an electric charge having a polarity opposite to the charged electric charge. It is a mixture of materials.

Further, in an image forming apparatus having a conveyance guide member whose guide surface for guiding the transfer paper on which an image is formed in the conveyance direction is formed of an insulating material, static electricity is charged in the insulating material. It is a mixture of a self-discharging static electricity neutralizing material that neutralizes a member by removing the charge with a charge having a polarity opposite to that of the charged charge when the member contacts the member. Then, in the image forming apparatus, it is effective to provide a pressing member that presses the transfer paper against the guide surface of the conveyance guide member in a conveyable state.

[0012]

According to the image forming apparatus constructed as described above, at least one of the fixing member and the pressure member of the fixing device, which is in contact with the transfer paper, is provided with a self-discharge type static neutralizing material in the surface coating material. Since it is formed of a mixed surface coat layer, when a charged transfer paper comes into contact with the surface of the surface coat layer when passing through it, the static electricity charged by the static electricity neutralizer has a polarity opposite to that of the charge. Is removed by the charge.

A fixing device having a fixing member and a pressure member for holding and fixing the transfer paper having the toner image transferred thereon, and at least one of the portions contacting the transfer paper is made of a rubber material. In an image forming apparatus equipped with, in the above-mentioned rubber material, when a member charged with static electricity is contacted, the member is neutralized by neutralizing by neutralizing the member with a charge having a polarity opposite to the charged electric charge. When a Japanese material is mixed, when the charged transfer paper comes into contact with the rubber material while passing therethrough, the static electricity neutralized by the static electricity neutralization material eliminates the charged static electricity with a charge having a polarity opposite to the charge.

Further, in the image forming apparatus provided with the conveyance guide member whose guide surface for guiding the transfer sheet on which the image is formed in the conveyance direction is formed of an insulating material, static electricity is charged in the insulating material. If a self-discharging static electricity neutralizing material that neutralizes the material by removing it with a charge of the opposite polarity when contacting the material is mixed, it will be conveyed when the charged transfer paper passes through it. When in contact with the guide surface of the guide member, the static electricity neutralized by the static electricity neutralizing material removes the static electricity with an electric charge having a polarity opposite to the charged electric charge.

In the image forming apparatus, if a pressing member that presses the transfer paper against the guide surface of the transfer guide member in a transportable state is provided, the transfer paper has a guide surface mixed with the static electricity neutralizer by the pressing member. Since it is conveyed while being pressed against, it is possible to perform more reliable static elimination.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be specifically described below with reference to the drawings. 1 is a schematic view showing a fixing device of an image forming apparatus according to an embodiment of the present invention, FIG. 2 is a perspective view showing one end side of a fixing roller provided in the fixing device, and FIG. 3 is the fixing device. 3 is a perspective view showing one end side of a pressure roller provided in FIG.

The image forming apparatus having the fixing device 11 shown in FIG. 1 forms a toner image on the transfer paper P by an electrophotographic method, and fixes the toner image by the fixing device 11. Although the image forming process by the electrophotographic method is publicly known and detailed description is omitted because it is not directly related to the present invention, the surface of the photosensitive drum is uniformly charged by corona discharge by a charging device, and A latent image is formed by irradiating and exposing light corresponding to the image, and toner is attached to the latent image by a developing device to form a visible image (toner image), which is transferred to a transfer paper by a transfer charger. After the paper is printed, it is fixed by the fixing device 11 and discharged to a paper discharge tray or the like outside the machine.

The fixing device 11 vertically presses a fixing roller 12 for sandwiching the transfer paper P on which the toner image has been transferred and fixing it by heat, and a pressure roller 13, and the fixing roller 12 has a cylindrical shape. As shown in FIG. 2, a surface coat layer 15 is formed on the outer peripheral surface of the metal roller 14 made of, for example, aluminum or iron in contact with the transfer paper P, and the heater 16 (for heating) is provided inside the metal roller 14. 1) is provided.

The surface coat layer 15 is a layer having a predetermined thickness formed by applying, for example, ethylene tetrafluoride having a good releasability to the outer peripheral surface of the metal roller 14, by which the toner image is transferred. The transfer sheet P is prevented from being wound around the fixing roller 12 and the toner is not fixed to the surface of the fixing roller 12.

As shown in FIG. 3, the pressure roller 13 is a tube in which a rubber roller 18 is integrally covered on the outside of a metal cored bar 17 formed in a cylindrical shape, and a surface coat layer is formed on the outer peripheral portion thereof. The surface-coated tube 19 is covered. In this embodiment, when the surface coating layer 15 of the fixing roller 12 shown in FIG. 2 is brought into contact with a member charged with static electricity, the member is neutralized by neutralizing by neutralizing the member with a charge having a polarity opposite to the charge. The surface coat material is mixed with the static electricity neutralizer 20 of the formula.

Similarly, the surface-coated tube 19 of the pressure roller 13 shown in FIG. 3 is also formed by mixing the above-mentioned self-discharge type static electricity neutralizing material 20 into the material at the time of its manufacture.
The self-discharge type static electricity neutralizing material (for example, trade name Soldion) 20 is a special function material for preventing static electricity, which has a structure different from the conventional antistatic material, and is a paper, rubber, plastic, coating agent, paint. It can be used widely by combining with other materials.

As its characteristic feature, the static electricity can be instantly neutralized and the static electricity of the contacted member can be attenuated without grounding, and the effect is instantly exhibited. Further, one of the characteristics is that the antistatic effect does not change with time, and a great effect is exhibited particularly in an environmental condition of low humidity.

This self-discharge type static electricity neutralizing material 20 neutralizes the contacting member by performing corona discharge from the tip of the conductive substance (fibrous substance) and removing the contacting member with a charge having a polarity opposite to the charge. To do. Therefore, the discharge mode is corona discharge, and the static elimination method is self-discharge type.

As described above, in this embodiment, the self-discharge type electrostatic neutralizer 20 is mixed in the surface coat layer 15 of the fixing roller 12 and the surface coat tube 19 covering the outer peripheral portion of the pressure roller 13. Therefore, even if the transfer sheet P which has formed an image and reaches the fixing device 11 shown in FIG. 1 is charged, the transfer sheet P is nipped and conveyed by the fixing roller 12 and the pressure roller 13. By contacting the static electricity neutralizing material 20 mixed in the surface coat layer 15 and the surface coat tube 19 at the time of passage, it is neutralized by a charge having a polarity opposite to that of the charge.

Since the static electricity neutralizing material 20 is a self-discharge type by corona discharge as described above, both the surface coating layer 15 of the fixing roller 12 and the surface coating tube 19 of the pressure roller 13 are subjected to this static elimination. No need to ground.

As in this embodiment, the fixing roller 1
When the static electricity neutralizing material 20 is mixed into both the pressure roller 13 and the pressure roller 13, even if the transfer paper is a material other than the paper such as the OHP sheet, the static electricity on the transfer paper can be effectively used. It can be removed. However, even when only one of the fixing roller 12 and the pressure roller 13 is mixed with the static electricity neutralizer 20, if the transfer paper is paper, the static electricity charged therein is effective. Can be discharged to.

FIG. 4 is a perspective view for explaining an embodiment in which the present invention is applied to a fixing device having a fixing roller without a surface coating, and the portions corresponding to FIG. 2 are designated by the same reference numerals. . This embodiment is suitable for a color electrophotographic image forming apparatus. In this image forming apparatus, in order to give a glossy image, a rubber roller layer 23 made of silicon rubber is integrally formed on the outside of the metal roller 14 to form the fixing roller 22, and the surface thereof is not coated. Instead, the self-discharging static electricity neutralizing material 20 described in FIGS. 2 and 3 is directly mixed into the rubber material forming the rubber roller layer 23.

Even in this way, when the charged transfer paper P passes through the fixing roller 22 while contacting it, the static electricity neutralizing material 20 that mixes the static electricity on the transfer paper P with which it comes into contact with the rubber roller layer 23. However, since the charge is removed by a charge having a polarity opposite to that of the charge, it is possible to prevent the transfer sheets from being attracted to each other, which is likely to occur when the transfer sheets are charged with static electricity.

FIG. 5 is a perspective view showing only an essential part of an embodiment of an image forming apparatus in which a static electricity neutralizing material is mixed in a guide surface of a conveying guide member for guiding a transfer sheet on which an image is formed in a conveying direction. In this embodiment, an example of an image forming apparatus in which the whole including a guide surface 35a for guiding the transfer sheet P on which an image is formed in the conveyance direction is provided with a conveyance guide member 35 formed of an insulating material such as plastic. As shown in FIG.
In addition, the self-discharge type static neutralizer 20 described in FIG. 3 is mixed.

That is, by mixing the static electricity neutralizing material 20 into the molding material in the process of injection molding the plastic transport guide member 35, the transport guide member 3 is formed.
When the transfer paper charged in 5 comes into contact, the static electricity can be removed.

In this way, the transfer paper P has the fixing device 31 provided with the fixing roller 32 and the pressure roller 33 after the toner has been fixed to the paper surface, and then the guide surface 3 of the conveying guide member 35.
Since it is conveyed toward the discharge port while sliding on 5a, static electricity is neutralized by the static electricity neutralizing material 20 when it comes into contact with the static electricity neutralizing material 20 mixed in the guide surface 35a during the transportation process. And the electricity is removed. Therefore, it is possible to prevent the transfer sheets from being attracted to each other due to static electricity.

As described above, in this embodiment, the electrostatic charge is removed by the charged transfer paper P coming into contact with the static electricity neutralizing material 20 mixed in the guide surface 35a of the transport guide member 35, so that the guide surface is removed. It is desirable that 35a be in contact with the transfer paper P in the widest possible range.

Therefore, the guide surface 3 of the conveyance guide member 35
If the entire surface of 5a is made flat so as to eliminate the protruding portion, the transfer paper P will be more likely to contact the static electricity neutralizing material 20 mixed in the transport guide member 35. Since the guide surface 35a is received by the entire guide surface 35a, it tends to become a resistance to the transfer paper conveyance.

Therefore, in such a case, as shown in FIG. 6, a plurality of ribs 36 are formed on the guide surface along the transfer sheet conveying direction (the direction indicated by the arrow A) like the conveying guide member 35 'shown in FIG. By alternately projecting the transfer paper at predetermined intervals, the frictional resistance when guiding the transfer paper can be reduced and the transfer paper can be transported smoothly.

Each rib 36 in FIG. 6 has an inclined portion 36a on the upstream side (right side in the figure) of the transfer sheet as shown in FIG.
Is provided so that the leading edge of the transfer paper is not caught in that portion. In addition, the rib is the rib 3 shown in FIG.
7, a large number of sheets are formed in parallel with each other while being inclined with respect to the transfer paper conveyance direction (arrow A direction), and are arranged symmetrically with respect to the center of the guide surface 35a in the paper width direction of the transfer paper. If you do, it will be effective.

FIG. 9 is a schematic view showing an embodiment of an image forming apparatus in which a self-discharge type static electricity neutralizing material is mixed in a conveyance guide member having a small radius of curvature in the reversing part, and FIG. 10 shows the same conveyance guide member. It is a perspective view. In this embodiment, for the purpose of reducing the space of a copying machine which is an image forming apparatus or combining a printer and a facsimile, for example, when the transfer paper is discharged on the back side, the transfer paper has a small radius of curvature and is used for reversing transfer paper. As shown in FIG. 10, the self-discharge type static electricity neutralizing material 20 described in FIG. 2 and the like is mixed in the conveyance guide member 45 forming the path.

As described above, if the static electricity neutralizing material 20 is mixed in the guide surface 45a of the conveyance guide member 45 provided in the reversal portion having a small radius of curvature, the conveyance path 4 in FIG.
Since the transfer paper P conveyed by 6 always contacts the guide surface 45a thereof, the static electricity on the transfer paper P is neutralized by the static electricity neutralizing material 2.
With 0, it is possible to surely eliminate the charge. FIG. 11 is a schematic view showing only an essential part of an embodiment of an image forming apparatus in which a transfer member is reliably pressed against a conveyance guide member by a pressing member.

In this embodiment, the transport guide plates 55 and 56 are provided on the downstream side of the fixing device 31 in the transport direction, and the self-discharge type static neutralizing material 20 is mixed on the downstream side thereof, and described with reference to FIG. A transfer guide member 57 made of plastic having a large number of ribs 36 formed on the upper surface thereof is arranged, and the transfer paper P can be transferred to the guide surface of the transfer guide member 57 (in this case, on the ribs 36). A pressing roller 58, which is a pressing member for pressing in this state, is provided.

By doing so, when the transfer paper P discharge path is linear, the transfer paper P is heated and pressurized by the fixing device 31 and then cooled as shown in FIG. If this happens, a wavy state may occur, but even in such a case, the transfer paper P has the pressing member 58 in which the static electricity neutralizing material 20 is mixed and the conveyance guide member 57.
Since the sheet is conveyed while being forcibly pressed against the guide surface, the static electricity on the transfer paper can be removed more reliably.

The example in which the self-discharge type static neutralizer 20 is mixed into various members in the image forming apparatus has been described above. The fixing devices in each of these examples are as follows.
The fixing roller having the heater inside as the fixing member and the pressure roller as the pressing member are both in contact with each other. However, the fixing device has a plate shape or other shape which is heated by the heater. The pressure roller may be brought into pressure contact with the fixing member,
Conversely, a pressure member having a guide surface in a plate shape or another shape may be pressed against the fixing roller.

[0041]

As described above, according to the present invention, the surface of at least one of the fixing member and the pressure member of the fixing device, which is in contact with the transfer paper, is self-discharge type electrostatic neutralization in the surface coating material. Since it is formed of a surface coat layer mixed with a material, if a charged transfer paper comes into contact with the surface of the surface coat layer while passing through it, the static electricity neutralizer will remove the charged static electricity. .

Therefore, since the static electricity charged on the transfer paper can be eliminated without using the static elimination brush, which is becoming troublesome to install while the weight reduction of the apparatus is progressing to the plasticization, the static elimination brush becomes unnecessary. The cost can be reduced by that much, and the assembling work is improved because it is not necessary to assemble the grounding cord connected to the static elimination brush to the position where the metal part is located.

If at least one of the fixing member and the pressure member of the fixing device, which is in contact with the transfer paper, is made of a rubber material, the static electricity neutralizing material may be mixed in the rubber material. If the charged transfer paper comes into contact with the rubber material while passing through it, the charged static electricity is neutralized by the static electricity neutralizing material, and thus the static elimination brush is also unnecessary.

Further, when the guide surface of the conveyance guide member is formed of an insulating material, if the above-mentioned static electricity neutralizing material is mixed into the insulating material, when the charged transfer paper passes through it. When touching the guide surface of the transport guide member,
Since the charged static electricity is neutralized by the static electricity neutralizing material, the static elimination brush is also unnecessary.

In this case, if a pressing member for pressing the transfer paper against the guide surface of the transfer guide member in a transportable state is provided, the transfer paper is pressed against the guide surface mixed with the static electricity neutralizing material by the pressing member. As it is conveyed while being transported, it is possible to perform more reliable charge removal.

[Brief description of drawings]

FIG. 1 is a schematic view showing a fixing device of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view showing one end side of a fixing roller provided in the fixing device.

FIG. 3 is a perspective view showing one end side of a pressure roller also provided in the fixing device.

FIG. 4 is a perspective view for explaining an embodiment in which the present invention is applied to a fixing device having a fixing roller without surface coating.

FIG. 5 is a perspective view showing only a main part of an embodiment of an image forming apparatus in which a static electricity neutralizing material is mixed in a guide surface of a conveyance guide member that guides a transfer sheet on which an image is formed in a conveyance direction.

FIG. 6 is a perspective view showing a conveyance guide member in which a large number of ribs along the conveyance direction of the transfer paper are projected on a guide surface mixed with an electrostatic neutralizer.

FIG. 7 is a front view showing a rib in which an inclined portion is provided on the upstream side in the transport direction of the transfer sheet to prevent the front end of the transfer sheet from being caught.

FIG. 8 is a plan view showing an example in which a plurality of ribs are arranged in parallel in parallel with each other with the ribs being inclined with respect to the transfer paper conveyance direction.

FIG. 9 is a schematic view showing an embodiment of an image forming apparatus in which a self-discharge type static neutralizer is mixed in a conveyance guide member having a small radius of curvature in a reversing portion.

FIG. 10 is a perspective view showing a conveyance guide member provided in the reversing unit of the image forming apparatus.

FIG. 11 is a schematic view showing only an essential part of an embodiment of an image forming apparatus in which a transfer member is reliably pressed against a conveyance guide member by a pressing member.

FIG. 12 is a schematic diagram for explaining a situation in which the wavy transfer paper is less likely to contact the guide surface of the conveyance guide member when the transfer paper discharge path is linear.

FIG. 13 is a schematic diagram showing step by step how the transfer sheets are attracted to each other by static electricity and the stack positions are displaced when the transfer sheets are discharged from the apparatus main body to a discharge tray.

FIG. 14 is a schematic diagram showing, step by step, how normal stacking cannot be performed when transfer sheets are attracted to each other by static electricity in a state where the ends of the transfer sheets are rounded.

FIG. 15 is a perspective view showing an example of an image forming apparatus in which a conductive static elimination brush is provided in a sheet discharge port of the apparatus main body to eliminate static electricity from a transfer sheet.

FIG. 16 is a schematic diagram showing a configuration in the vicinity of a sheet discharge port of the image forming apparatus.

FIG. 17 is a perspective view showing an example of an image forming apparatus in which one end side of a grounding cord attached to the base portion of a static elimination brush is attached to a main body side plate made of sheet metal.

[Explanation of symbols]

11, 31 Fixing device 12, 22, 32 Fixing roller (fixing member) 13, 33 Pressure roller (pressurizing member) 15 Surface coat layer 18 Rubber roller 19 Surface coat tube 20 Static neutralizer 23 Rubber roller layer 35, 45, 57 Transport guide members 35a, 4
5a guide surface 58 pressing member

Claims (4)

[Claims] 1. A fixing device comprising a fixing member for sandwiching a transfer sheet having a toner image transferred thereon and fixing it by heating, and a pressure member, and a surface coat layer is formed on at least one of the surfaces in contact with the transfer sheet. In an image forming apparatus equipped with a device, a self-discharge type static electricity neutralization for neutralizing the surface coat layer by neutralizing the static electricity charged member by removing the charge with a charge having a polarity opposite to that of the charged charge An image forming apparatus characterized by being formed of a surface coating material mixed with a material. 2. A fixing device having a fixing member for sandwiching and fixing the transfer paper on which the toner image is transferred by heating, and a pressure member, and at least one of the portions in contact with the transfer paper is formed of a rubber material. In an image forming apparatus equipped with, a self-discharge type static electricity in the rubber material, which neutralizes the static electricity charged member by neutralizing the member with a charge having a polarity opposite to that of the charged charge An image forming apparatus in which a Japanese material is mixed. 3. An image forming apparatus comprising a conveyance guide member whose guide surface for guiding a transfer sheet on which an image is formed in a conveyance direction is formed of an insulating material, wherein static electricity is charged in the insulating material. An image forming apparatus comprising a self-discharge type static neutralization material for neutralizing a member by removing the charge with a charge having a polarity opposite to that of the charged charge when the member is in contact with the member. 4. The image forming apparatus according to claim 3,
An image forming apparatus, comprising: a pressing member that presses the transfer paper against the guide surface of the transfer guide member in a transportable state.