JP7062964B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming apparatus having a fixing device for fixing a developer transferred to a recording medium.

In a conventional image forming apparatus, in a fuser having a fixing member for fixing a developer transferred to a recording medium by heat and pressure, a conductive member is mixed with a rubber layer of the fixing member to suppress thermal deterioration of the rubber layer. At the same time, the electrostatic offset in which the developer is electrostatically attached to the surface of the fixing member is suppressed. Further, an organic magnetic substance is mixed in the adhesive layer of the fixing member to suppress thermal deterioration of the rubber layer (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2007-148192

However, in the conventional technique, when the conductive member is mixed in the rubber layer of the fixing member, the rubber layer of the fixing member becomes hard, which causes poor fixing of the developer and prints on a medium having high charge and high resistance. In this case, since the electric charge accumulated on the surface layer is not erased, there is a problem that the developer image transferred to the recording medium is disturbed, further fixing failure is caused, and the print quality is deteriorated.
An object of the present invention is to solve such a problem, and an object of the present invention is to suppress fixing defects and improve print quality.

Therefore, the present invention has a fixing device for fixing the developer image transferred to the recording medium, and the fixing device includes a rotatable endless fixing member and a guide member in contact with the end face of the fixing member. The fixing member has a surface layer in contact with a recording medium, an elastic layer inside the surface layer, and an intermediate layer disposed between the surface layer and the elastic layer. The guide member contains a conductive member, the intermediate layer contains a conductive member, and a conductive member having conductivity is formed on the side surface of the intermediate layer and the elastic layer on the guide member side with the intermediate layer. It is continuously applied between the elastic layer, the conductive member is in contact with the guide member, and the intermediate layer is in contact with the intermediate layer and the guide member via the conductive member . It is a feature.

The present invention in this manner has the effect of suppressing fixing defects and improving the print quality.

Schematic side sectional view showing the configuration of the image forming apparatus in the embodiment. Schematic side sectional view showing the configuration of the fixing unit in the embodiment. Explanatory drawing which shows the structure of the fixing unit in an Example Explanatory drawing of fixing belt, fixing belt flange, and fixing sheet metal in an Example Explanatory drawing of conductive member content of primer layer in Example Explanatory diagram of charge flow on the surface layer of the fixing belt in the embodiment Explanatory diagram of charge flow on the surface layer of the fixing belt at the time of fixing the highly charged medium in the comparative example. Explanatory drawing of fixing belt, fixing belt flange, and fixing sheet metal in modification 1. Explanatory drawing which shows the structure of the fixing belt in the modification 2 Explanatory drawing of fixing belt, fixing belt flange, and fixing sheet metal in modification 2 Explanatory drawing of fixing belt, fixing belt flange, and fixing sheet metal in modification 3

Hereinafter, examples of the image forming apparatus according to the present invention will be described with reference to the drawings.

FIG. 1 is a schematic side sectional view showing a configuration of an image forming apparatus in an embodiment.

In FIG. 1, the image forming apparatus 1 forms an image on a recording medium P and prints it, and is, for example, a printer. The image forming apparatus 1 includes a medium cassette 3, a winding unit 4, a process unit 10, a transfer belt unit 20, a fixing unit 30, and a cutter unit 70. In this embodiment, the image forming apparatus 1 will be described as a color printer, but a monochrome printer may be used. Further, in the present embodiment, the printer for printing the continuous recording medium P will be described, but the printer may be used for printing a standard recording medium (precut paper) cut into a predetermined size in advance.

The medium cassette 3 winds and accommodates the recording medium P before printing. The recording medium P is continuous paper, and is a label paper to which a label is attached, glossy paper, a resin medium, a transparent film medium, or the like.
The recording medium P housed in the medium cassette 3 is drawn out by the pickup roller 41, and is taken up by the resist roller pair 42, the transport roller pair 43, 44, the secondary transfer roller 45, the transport roller pair 46, and the discharge roller pair 47. It is transported to 4.

The pickup roller 41 rotates to transport the recording medium P housed in the medium cassette 3 in the medium transport direction indicated by the arrow A2 in the drawing. At this time, the recording medium P wound around the medium cassette 3 is pulled out and rotates in the direction indicated by the arrow A1 in the drawing.
The resist roller pair 42 is arranged downstream of the pickup roller 41 in the medium transport direction, sandwiches the recording medium P drawn out by the pickup roller 41, and transports the resist roller pair 42 in the medium transport direction indicated by the arrow A3 in the drawing.

The transport roller pair 43 is arranged downstream of the resist roller pair 42 in the medium transport direction, sandwiches the recording medium P transported by the resist roller pair 42, and transports the recording medium P in the medium transport direction indicated by the arrow A4 in the drawing.
The transfer roller pair 44 is located downstream of the transfer roller pair 43 in the medium transfer direction and upstream of the secondary transfer roller 45, sandwiches the recording medium P conveyed by the transfer roller pair 43, and moves in the medium transfer direction. Transport. The transfer roller pair 44 can control the timing of the secondary transfer performed by the secondary transfer roller 45 by rotating or stopping the transfer roller pair 44.

The secondary transfer roller 45 is arranged so as to come into contact with the backup roller 48 via the transfer belt 28 of the transfer belt unit 20 to form a secondary transfer portion. The secondary transfer roller 45 transfers the recording medium P in the medium transport direction by applying a transfer voltage and rotating, and transfers the toner image as a developer image formed on the transfer belt 28 to the recording medium P. ..
The transfer roller pair 46 is arranged downstream of the secondary transfer roller 45 and the fixing unit 30 in the medium transfer direction, sandwiches the recording medium P conveyed by the secondary transfer roller 45 and the fixing unit 30, and transfers in the medium transfer direction. do.

The discharge roller pair 47 is arranged downstream of the transport roller pair 46 in the medium transport direction, sandwiches the recording medium P transported by the transport roller pair 46, and transports the recording medium P in the medium transport direction indicated by the arrow A6 in the drawing.
The take-up unit 4 winds up and accommodates the recording medium P conveyed by the discharge roller pair 47. The take-up unit 4 winds and accommodates the recording medium P so that it rotates in the direction indicated by the arrow A7 in the drawing so that the printing surface faces the inside.

It should be noted that the medium passage sensor 60 that detects the passage of the recording medium P between the resist roller pair 42 and the transfer roller pair 43, and the passage of the recording medium P between the transfer roller pair 43 and the transfer roller pair 44 are detected. A writing sensor 62 that detects the passage of the recording medium P between the transfer roller pair 44 and the secondary transfer roller 45 and controls the timing of the secondary transfer, the fixing unit 30 and the discharge roller pair 47. An discharge sensor 63 for detecting the passage of the recording medium P is arranged between the two. The medium passage sensor 60, the medium passage sensor 61, the write sensor 62, and the discharge sensor 63 are, for example, mechanical sensors that operate mechanically.

The process unit 10 is composed of each electrophotographic process unit of process units 11, 12, 13, 14, and 15, and in the case of the image forming apparatus 1 for color printing, the process unit 10 is divided according to the color of the toner as a developer to be handled. There is. For example, the process unit 11 is a special color toner such as white toner or clear toner, the process unit 12 is a cyan toner, the process unit 13 is a magenta toner, the process unit 14 is a yellow toner, and the process unit 15 is a black toner. It forms an image of toner.

The transfer belt unit 20 is an intermediate transfer belt unit and has primary transfer rollers 21, 22, 23, 24, 25, tension rollers 26, 27, a backup roller 48, and a transfer belt 28. ..
The primary transfer rollers 21, 22, 23, 24, and 25 are arranged to face each other via the transfer belt 28 so as to be in contact with the photosensitive drum as the image carrier of the process units 11, 12, 13, 14, and 15, and transfer. By applying a voltage, the toner image formed on the photosensitive drums of the process units 11, 12, 13, 14, and 15 is transferred to the transfer belt 28.

The tension rollers 26, 27 stretch the transfer belt 28 and rotate the transfer belt 28 in the belt traveling direction indicated by arrows B1, B2, and B3 in the figure.
The backup roller 48 is placed so as to be in contact with the secondary transfer roller 45 via the transfer belt 28, and forms a nip portion (contact portion) as a secondary transfer portion between the backup roller 48 and the secondary transfer roller 45. It is a thing.

The transfer belt 28 is stretched on the tension rollers 26, 27 and the backup roller 48, and rotates in the belt traveling direction indicated by the arrows B1, B2, and B3 in the figure, and the process units 11, 12, 13, 14, The toner image formed by 15 and transferred by the primary transfer rollers 21, 22, 23, 24, 25 is conveyed.

The toner image transferred to the transfer belt 28 is transferred to the recording medium P by passing the nip portion formed by the secondary transfer roller 45 and the backup roller 48 through the recording medium P.
The fixing unit 30 as a fixing device fixes the toner image transferred to the recording medium P by the secondary transfer unit by heat and pressure, and has a pressure belt 40 and a fixing belt 50. The pressure belt 40 and the fixing belt 50 are rotatable belts arranged so as to be in contact with each other. The details of the fixing unit 30 will be described later.

The cutter unit 70 is downstream of the pickup roller 41 in the medium transport direction, is arranged upstream of the resist roller pair 42, is pulled out by the pickup roller 41, and cuts the recording medium P transported by the resist roller pair 42. Is.

The image forming apparatus 1 configured in this way includes a control means such as a CPU (Central Processing Unit), and the entire operation is controlled by the control means based on the control program (software) stored in the storage means such as a memory. Will be done.

FIG. 2 is a schematic side sectional view showing the configuration of the fixing unit in the embodiment.

In FIG. 2, the fixing unit 30 has a temperature detecting element 31, a pressure belt 40, a fixing belt 50, rollers 32 and 33, pads 34 and 35, and heaters 36 and 37.

The pressure belt 40 is an endless belt, and is provided so as to be rotatable in the direction indicated by the arrow C2 in the figure. The pressure belt 40 may be a rubber belt using a rubber material, or may be a metal belt using a SUS (stainless steel) material.
The fixing belt 50 as a fixing member is an endless belt, and is provided so as to be rotatable in the direction indicated by the arrow C1 in the figure. The fixing belt 50 may be a rubber belt made of a rubber material or a metal belt made of a SUS material. The configuration of the fixing belt 50 of this embodiment will be described later.

The roller 32 is arranged inside the fixing belt 50, and the roller 33 is arranged inside the pressure belt 40.
The pad 34 is arranged inside the fixing belt 50, and the pad 35 is arranged inside the pressure belt 40.

The pressure belt 40 and the fixing belt 50 are arranged so as to be pressed against each other by the rollers 33 and the pads 35, and the rollers 32 and the pads 34 so as to be in contact with each other.
The heaters 36 and 37 are heat sources arranged inside the fixing belt 50 and heat the fixing belt 50. The heaters 36 and 37 are heat sources typified by, for example, halogen heaters.

The temperature detecting element 31 is an element that measures the surface temperature of the fixing belt 50 in a non-contact manner, and is, for example, a thermistor or a thermopile.
FIG. 3 is an explanatory diagram showing the configuration of the fixing unit in the embodiment. FIG. 3 shows the fixing unit 30 seen from the upstream side in the medium transport direction of the recording medium P indicated by the arrow A in the figure.

In FIG. 3, both end faces of the fixing belt 50 in the medium transport direction are in contact with the fixing belt flange 501.
The fixing belt flange 501 as a guide member comes into contact with both end faces of the fixing belt 50 rotating in the direction indicated by the arrow C1 in the drawing, and guides both end portions of the fixing belt 50, and is fixed to the fixing sheet metal 503. It is a thing. Therefore, the fixing belt 50 rotates while sliding with the fixing belt flange 501.

Further, both end faces of the pressure belt 40 in the medium transport direction are in contact with the pressure belt flange 401.
The pressure belt flange 401 guides both end portions of the pressure belt 40 that rotates in the direction indicated by the arrow C2 in the figure, and is fixed to the fixing sheet metal 503. Therefore, the pressure belt 40 rotates while sliding with the pressure belt flange 401.

The fixing belt flange 501 and the pressure belt flange 401 are fixed to the fixing sheet metal 503 with screws or the like.
FIG. 4 is an explanatory diagram of the fixing belt, the fixing belt flange, and the fixing sheet metal in the embodiment. Note that FIG. 4 schematically shows the laminated structure of the fixing belt 50 and the connection form of the fixing belt 50, the fixing belt flange 501, and the fixing sheet metal 503. Although FIG. 4 shows one side end of the fixing belt 50, the other side end has the same configuration.

In FIG. 4, the fixing belt 50 has a PFA layer 511, a conductive primer layer 512, a silicone rubber layer 513, a primer layer 514, and a SUS layer 515. The fixing belt 50 of this embodiment is laminated in the order of the SUS layer 515, the primer layer 514, the silicone rubber layer 513, the conductive primer layer 512, and the PFA layer 511.

The PFA layer 511 as a surface layer is a release layer that forms the surface layer of the fixing belt 50 that comes into contact with the recording medium, and is a layer formed of PFA (perfluoroalkoxy fluororesin).
In this embodiment, the surface layer of the fixing belt 50 will be described as a PFA layer, but another resin layer (for example, a PTFE (polytetrafluoroethylene) layer) or the like may be used.

The silicone rubber layer 513 as the elastic layer is a rubber layer inside the PFA layer 511 and formed between the PFA layer 511 and the SUS layer 515.
The SUS layer 515 as a metal base material is a layer forming an inner layer of the fixing belt 50, and is made of a SUS material. The SUS layer 515 is arranged inside the silicone rubber layer 513 on the opposite side of the conductive primer layer 512 with the silicone rubber layer 513 as a reference so as to be in contact with the fixing belt flange 501.

As described above, the inner layer of the fixing belt 50 is composed of the SUS layer 515 in order to increase the thermal conductivity, and the SUS layer 515 is heated by the heaters 36 and 37 shown in FIG.

The conductive primer layer 512 as an intermediate layer (first intermediate layer) is a layer between the PFA layer 511 and the silicone rubber layer 513, contains a conductive member, and is conductive. The conductive primer layer 512 of this embodiment is a layer for adhering the PFA layer 511 and the silicone rubber layer 513, and is a layer in which a conductive member is mixed with the adhesive material. In this embodiment, the conductive primer layer 512 will be described as a layer for adhering the PFA layer 511 and the silicone rubber layer 513, but if it is a layer between the PFA layer 511 and the silicone rubber layer 513, the adhesiveness will be improved. It may not have.

The primer layer 514 as an intermediate layer (second intermediate layer) is a layer for adhering the silicone rubber layer 513 and the SUS layer 515. The primer layer 514 of this example is made of a fluorine-based adhesive. The primer layer 514 does not have to contain a conductive member.
The side end faces of the PFA layer 511, the conductive primer layer 512, the silicone rubber layer 513, the primer layer 514, and the SUS layer 515 of the fixing belt 50 are arranged so as to be in contact with the fixing belt flange 501. Further, the fixing belt flange 501 is fixed to the fixing sheet metal 503.

The fixing belt flange 501 is fixed to the fixing sheet metal 503, and the fixing sheet metal 503 is connected to the device sheet metal 505 via an element 504 mainly composed of a resistor, a varistor, or the like.
The device sheet metal 505 is grounded via a control board or the like. Further, the element 504 is provided to suppress the amount of electric charge flowing through the device sheet metal 505 to a predetermined amount, and the fixing sheet metal 503 and the device sheet metal 505 may be directly connected without passing through the element 504. ..

Here, a conductive member is mixed in the conductive primer layer 512 of this embodiment, and a conductive member is mixed in the fixing belt flange 501.
The conductive primer layer 512 is obtained by mixing a conductive member (for example, carbon black, a metal oxide, a fluorine-containing ion conductive material, etc.) with a fluorine-based adhesive (for example, a fluorine-based primer (manufactured by DuPont)).

In this embodiment, the content of the conductive member of the conductive primer layer 512 is 10% by weight or more and 20% by weight or less. As shown in FIG. 5, when the content of the conductive member is 10% by weight or more and 20% by weight or less, good adhesiveness can be obtained and good conductivity can be obtained. Because it can be done. In addition, "◯" in FIG. 5 indicates that it is good, and “×” indicates that it is defective.

Further, the fixing belt flange 501 is made by mixing a conductive member (for example, carbon black or graphite) with a resin material (for example, PEEK (polyetheretherketone) material or PPS (polyphenylene sulfide) material).

The base material of the fixing belt flange 501 is made of a resin material in order to suppress wear of the fixing belt flange 501, generation of abrasion powder, generation of abnormal noise, etc. due to contact with the fixing sheet metal 503.

As described above, in this embodiment, the fixing belt flange 501 of the fixing unit contains a conductive member, and the conductive primer layer 512 of the fixing belt 50 contains a conductive member, and the conductive primer layer 512 and the fixing belt. The fixing unit is configured so as to come into contact with the flange 501.

The operation of the above-mentioned configuration will be described.

First, an outline of the image forming operation performed by the image forming apparatus will be described with reference to FIG.

When the image forming apparatus 1 inputs a command to instruct printing from an external device such as a host computer or an operation panel, the pickup roller 41, the resist roller pair 42, the transport roller pair 43, 44, the secondary transfer roller 45, and the transport roller While rotating the pair 46, the discharge roller pair 47, and the winding unit 4, the operation of the process unit 10 is started, and the image forming operation is started.

The recording medium P housed in the medium cassette 3 is pulled out by the pickup roller 41 and is conveyed to the secondary transfer roller 45 by the resist roller pair 42 and the transfer roller pairs 43 and 44.
At this time, the toner image formed by the process unit 10 and primarily transferred onto the transfer belt 28 by the primary transfer rollers 21, 22, 23, 24, and 25 is transferred to the secondary transfer roller 45.

The toner image on the transfer belt 28 is secondarily transferred to the recording medium P by the secondary transfer roller 45, and the toner image secondarily transferred to the recording medium P is conveyed to the fixing unit 30.

As shown in FIGS. 2 and 3, the fixing unit 30 sandwiches the recording medium P by the pressure belt 40 and the fixing belt 50 to convey the recording medium P, and the toner on the recording medium P is transferred by heat and pressure. Fix the image.
The recording medium P on which the toner image is fixed by the fixing unit 30 is conveyed to the winding unit 4 by the transport roller pair 46 and the discharge roller pair 47 and wound up.
The recording medium P is cut by the cutter unit 70 as needed.

In this way, the image forming apparatus 1 performs the image forming operation.

Next, the operation of the fixing belt 50 of the fixing unit 30 shown in FIGS. 2 and 3 will be described with reference to the explanatory diagram of the charge flow on the surface layer of the fixing belt in the embodiment of FIG.

In FIG. 6, when the toner image is fixed on a recording medium having high resistance and high charge, the PFA layer 511, which is the surface layer of the fixing belt 50, may be charged as a charge E.
The electric charge E charged in the PFA layer 511 is transmitted in the order of the conductive primer layer 512, the fixing belt flange 501, the fixing sheet metal 503, and the connecting member 504, and is transmitted to the device sheet metal 505.
Therefore, since the electric charge E charged on the PFA layer 511 does not remain on the fixing belt 50, it is possible to form a toner image with good image quality on the recording medium P.

As described above, in this embodiment, the PFA layer is provided by providing the conductive primer layer 512 in contact with the PFA layer 511 which is the surface layer of the fixing belt 50, and by making the fixing belt flange 501 in contact with the conductive primer layer 512 conductive. It is possible to prevent the 511 from becoming hard and to release the charged charge near the PFA layer 511 via the fixing belt flange 501, and it is possible to form a toner image with good image quality on the recording medium P. ..

Here, a comparative example shown in FIG. 7 will be described.

The fixing belt 50 of the comparative example shown in FIG. 7 has a PFA layer 511, a primer layer 519, a silicone rubber layer 513, a primer layer 514, and a SUS layer 515.
The primer layer 519 is a layer for adhering the PFA layer 511 and the silicone rubber layer 513, and is not mixed with a conductive member.

Further, the fixing belt flange 509 is in contact with the side end surface of the fixing belt 50, and the conductive member is not mixed.

Since the PFA layer 511, the silicone rubber layer 513, the primer layer 514, the SUS layer 515, the fixing belt flange 501, the fixing sheet metal 503, and the element 504 have the same configuration as shown in FIG. 4, the description thereof will be omitted.

In the comparative example shown in FIG. 7, when the toner image is fixed on a recording medium having high resistance and high charge, the PFA layer 511, which is the surface layer of the fixing belt 50, may be charged as a charge E.
Since the PFA layer 511 is an insulator, the surface resistance is high (for example, 1 × 10 ⁶ Ω), and the fixing belt flange 509 is made of a member mainly composed of a high heat resistant resin, so that the surface resistance is high. There is a state in which the charged charge E is difficult to move in the horizontal direction indicated by the arrow D1 in the figure.

Further, the primer layer 519, the silicone rubber layer 513, and the primer layer 514 also have high resistance, and the charge E charged in the PFA layer 511 is in a state where it is difficult to move in the stacking direction of the fixing belt 50 indicated by the arrow D2 in the figure.
Therefore, the electric charge E charged in the PFA layer 511 stays in the PFA layer 511 without being transmitted to the primer layer 519 or to the fixing belt flange 509.

As described above, in the comparative example, the negatively charged charge E on the PFA layer 511 remains on the fixing belt 50, and the charge E remaining on the fixing belt 50 is conveyed by the rotation of the fixing belt 50 once. It is transferred to the belt and disturbs the negatively charged toner image, causing an afterimage and deteriorating the image quality.

In particular, when the recording medium P is continuous paper, the charged charge E does not stay in the PFA layer 511 of the fixing belt 50 and escape, so that the toner image of the recording medium P is disturbed and an afterimage is caused, resulting in image quality. Will be reduced.
On the other hand, in the fixing belt 50 of the present embodiment, since the charged E does not remain in the PFA layer 511, the toner image transferred to the recording medium P is not disturbed, and a toner image with good image quality is formed. can do.

Next, the modification 1 of this embodiment will be described based on the explanatory view of the fixing belt, the fixing belt flange, and the fixing sheet metal in the fixing belt 1 in the modification 1 of FIG.

The fixing belt 50 of the modification 1 shown in FIG. 8 has a PFA layer 511, a conductive primer layer 512, a silicone rubber layer 513, a primer layer 514, a SUS layer 515, and a conductive member 5121. Since the PFA layer 511, the conductive primer layer 512, the silicone rubber layer 513, the primer layer 514, the SUS layer 515, the fixing belt flange 501, the fixing sheet metal 503, and the element 504 have the same configuration as shown in FIG. 4, the description thereof will be omitted. .. Further, although FIG. 8 shows one side end of the fixing belt 50, the other side end has the same configuration.

The conductive member 5121 has conductivity applied to the side end faces of the conductive primer layer 512, the silicone rubber layer 513, and the primer layer 514 on the fixing belt flange 501 side, and the conductive primer layer 512 and the silicone rubber layer 513. And is continuously applied between the primer layer 514 and the primer layer 514.

The conductive member 5121 is arranged between the side end faces of the conductive primer layer 512, the silicone rubber layer 513, and the primer layer 514 and the fixing belt flange 501 so as to be in contact with the fixing belt flange 501, and the conductive primer layer 512 is provided. , The side end faces of the silicone rubber layer 513 and the primer layer 514 are connected to the fixing belt flange 501. The conductive member 5121 is made of the same material as the conductive primer layer 512.

As described above, in the first modification, the side end faces of the conductive primer layer 512, the silicone rubber layer 513, and the primer layer 514 are in contact with the fixing belt flange 501 via the conductive member 5121. The conductive member 5121 is provided at both end portions of the fixing belt 50.
In the first modification, the electric charge E charged in the PFA layer 511 is transmitted in the order of the conductive primer layer 512, the conductive member 5121, the fixing belt flange 501, the fixing sheet metal 503, and the connecting member 504, and is transmitted to the device sheet metal 505.

In the first modification, the conductive member 5121 is applied to the side end faces of the conductive primer layer 512, the silicone rubber layer 513, and the primer layer 514, so that the end face of the fixing belt 50 is compared with the case where the conductive member 5121 is not applied. The contact area with the fixing belt flange 501 can be increased, and the electrical resistance between the end face of the fixing belt 50 and the fixing belt flange 501 can be suppressed.

Therefore, since the electric charge E charged on the PFA layer 511 does not remain on the fixing belt 50, it is possible to form a toner image with good image quality on the recording medium P.

In the first modification, the side end faces of the conductive primer layer 512, the silicone rubber layer 513, and the primer layer 514 and the fixing belt flange 501 are brought into contact with each other via the conductive member 5121, but the conductive primer layer 512 and The side end surface of the silicone rubber layer 513 and the fixing belt flange 501 may be brought into contact with each other via the conductive member 5121. That is, it is also possible to prevent the side end surface of the primer layer 514 from coming into contact with the fixing belt flange 501 via the conductive member 5121.

Next, the modified example 2 of this embodiment is based on an explanatory diagram showing the configuration of the fixing belt in the modified example 2 of FIG. 9, and an explanatory diagram of the fixing belt, the fixing belt flange, and the fixing sheet metal in the modified example 2 of FIG. I will explain.

The fixing belt 50 of the modification 2 shown in FIGS. 9 and 10 has a PFA layer 511, a conductive primer layer 512, a silicone rubber layer 513, a primer layer 514, a SUS layer 515, and a conductive member 5122. ing. Since the PFA layer 511, the conductive primer layer 512, the silicone rubber layer 513, the primer layer 514, the SUS layer 515, the fixing belt flange 501, the fixing sheet metal 503, and the element 504 have the same configuration as shown in FIG. 4, the description thereof will be omitted. .. Further, although FIG. 10 shows one side end portion of the fixing belt 50, the other side end portion has the same configuration.

As shown in FIG. 9, the conductive member 5122 is formed on the fixing belt 50 in the central portion side from the side end surface of the fixing belt 50 and on the side end surface side from the region through which the print medium P passes, that is, in the region where the print medium P does not pass. It has conductivity and is formed by stretching so as to make one round in the rotation direction.
As shown in FIG. 10, the conductive member 5122 is formed by being injected into a groove as a penetrating portion formed so as to penetrate the silicone rubber layer 513 and the primer layer 514. The conductive member 5122 is made of the same material as the conductive primer layer 512.

As described above, in the second modification, the conductive primer layer 512 and the fixing belt flange 501 come into contact with each other, and the conductive primer layer 512 and the SUS layer 515 conduct with each other via the conductive member 5122 to be fixed to the conductive primer layer 512. The belt flange 501 is conductive via the conductive member 5122 and the SUS layer 515.

In the second modification, the conductive members 5122 are provided on both side ends of the fixing belt 50 one by one. However, two or more conductive members 5122 may be provided on both side ends, and at least one side thereof. One may be provided at the end.

Further, the conductive member 5122 may be injected into a through hole formed as a through portion penetrating the silicone rubber layer 513 and the primer layer 514 instead of the above-mentioned groove. A plurality of the through holes may be arranged in the rotation direction of the fixing belt 50 in the region where the print medium P does not pass.

In the second modification, the electric charge E charged in the PFA layer 511 is transmitted in the order of the conductive primer layer 512, the conductive member 5122, the SUS layer 515, the fixing belt flange 501, the fixing sheet metal 503, and the connecting member 504, and is transmitted to the device sheet metal 505. ..
Further, the electric charge E charged in the PFA layer 511 is transmitted in the order of the conductive primer layer 512, the conductive primer layer 512, the fixing belt flange 501, the fixing sheet metal 503, and the connecting member 504, and is transmitted to the device sheet metal 505.

In the second modification, the conductive member 5122 is arranged in the grooves formed in the silicone rubber layer 513 and the primer layer 514, and the conductive primer layer 512 and the SUS layer 515 are connected by the conductive member 5122, thereby further forming the PFA layer 511. The electrical resistance between the fixing belt flange 501 and the fixing belt flange 501 can be suppressed.

Therefore, since the electric charge E charged on the PFA layer 511 does not remain on the fixing belt 50, it is possible to form a toner image with good image quality on the recording medium P.

Next, the modification 3 of this embodiment will be described based on the explanatory view of the fixing belt, the fixing belt flange, and the fixing sheet metal in the fixing belt 3 in the modification 3 of FIG.

The fixing belt 50 of the modification 3 shown in FIG. 11 has a PFA layer 511, a conductive primer layer 512, a silicone rubber layer 513, a primer layer 514, a SUS layer 515, and a conductive member 5011. Since the PFA layer 511, the conductive primer layer 512, the silicone rubber layer 513, the primer layer 514, the SUS layer 515, the fixing belt flange 501, the fixing sheet metal 503, and the element 504 have the same configuration as shown in FIG. 4, the description thereof will be omitted. .. Further, although FIG. 11 shows one side end portion of the fixing belt 50, the other side end portion has the same configuration.

The conductive member 5011 is provided on the fixing belt flange 501 between the PFA layer 511, the conductive primer layer 512, the silicone rubber layer 513, the primer layer 514, and the SUS layer 515 of the fixing belt 50, and is in contact with at least the conductive primer layer 512. It is fixed to the fixing belt flange 501. The conductive member 5011 is made of the same material as the conductive primer layer 512.

In the third modification, the side end faces of the PFA layer 511, the conductive primer layer 512, the silicone rubber layer 513, the primer layer 514, and the SUS layer 515, and the fixing belt flange 501 are in contact with each other via the conductive member 5011.
Further, the conductive member 5011 has an inclined portion 5011a on which an inclined surface is formed, and the inclined portion (inclined surface) 5011a and the side surface 501a on the fixing belt 50 side of the fixing belt flange 501 have an angle α (for example, 4). It is formed so as to form (~ 5 degrees).

As described above, in the modification 3, in the fixing belt flange 501, the inclined portion 5011a of the conductive member 5011 having conductivity is formed on the side surface on the fixing belt 50 side, and the conductive member 5011 and the conductive primer layer 512 are fixed. The belt 50 is in contact with the belt 50 on an inclined surface with respect to the stacking direction indicated by the arrow D2 in the figure.

In the modification 3, the electric charge E charged in the PFA layer 511 is transmitted in the order of the conductive primer layer 512, the conductive member 5011, the fixing belt flange 501, the fixing sheet metal 503, and the connecting member 504, and is transmitted to the device sheet metal 505.

In the modified example 3, the side end surface of the PFA layer 511, at least the conductive primer layer 512, and the fixing belt flange 501 are brought into contact with each other via the conductive member 5011, so that the case where the conductive member 5011 is not provided is compared with the case where the conductive member 5011 is not provided. The contact area between the end face of the conductive primer layer 512 of the fixing belt 50 and the fixing belt flange 501 can be increased, and the electrical resistance between the end face of the fixing belt 50 and the fixing belt flange 501 can be suppressed.

Therefore, since the electric charge E charged on the PFA layer 511 does not remain on the fixing belt 50, it is possible to form a toner image with good image quality on the recording medium P.

Further, by setting the angle α formed by the inclined portion 5011a of the conductive member 5011 and the side surface 501a on the fixing belt 50 side of the fixing belt flange 501 to 4 to 5 degrees, the conductive primer layer 512 of the fixing belt 50 and the fixing belt flange The contact area with 501 can be increased, and the conductive primer layer 512 of the rotating fixing belt 50 and the fixing belt flange 501 can be in constant contact with each other.

As described above, in the modified example 3, both stable rotational running of the fixing belt 50 and low electric resistance between the end face of the fixing belt 50 and the fixing belt flange 501 can be achieved at the same time.

Although the recording medium P has been described as continuous paper in this embodiment and each modification, it may be a standard recording medium (precut paper) cut into a predetermined size in advance.

As described above, in the present embodiment, the conductive primer layer in contact with the surface layer of the fixing belt is provided, and the fixing belt flange in contact with the conductive primer layer is made conductive to prevent the surface layer from becoming hard and also to prevent the surface layer from becoming hard. It becomes possible to release the charged charge near the surface layer through the fixing belt flange, and even if the recording medium has high charge and high resistance, the toner image with good image quality does not cause an afterimage on the recording medium. The effect of being able to form is obtained.

In this embodiment, the image forming apparatus is described as a color printer, but the present invention is not limited to this, and if it has a fixing unit, it is a monochrome printer, a copying machine, a facsimile machine, a multifunction device (MFP), or the like. It may be.

1 Image forming device 3 Medium cassette 4 Winding unit 10, 11, 12, 13, 14, 15 Process unit 20 Transfer belt unit 30 Fixing unit 31 Temperature detection element 32, 33 Roller 34, 35 Pad 36, 37 Heater 40 Pressurization Belt 50 Fixing belt 70 Cutter unit 401 Pressurized belt Flange 501 Fixing belt flange 503 Fixing sheet metal 511 PFA layer 512 Conductive primer layer 513 Silicone rubber layer 514 Primer layer 515 SUS layer 5011, 5121, 5122 Conductive member

Claims (6)

It has a fuser that fixes the developer image transferred to the recording medium.
The fuser is
A rotatable endless fixing member and
A guide member that comes into contact with the end face of the fixing member,
Have,
The fixing member is
The surface layer that comes into contact with the recording medium,
The elastic layer inside the surface layer and
An intermediate layer disposed between the surface layer and the elastic layer,
Have,
The guide member contains a conductive member and has a conductive member.
The intermediate layer contains a conductive member and has a conductive member.
A conductive member having conductivity is continuously applied between the intermediate layer and the elastic layer on the side surfaces of the intermediate layer and the elastic layer on the guide member side.
The conductive member comes into contact with the guide member,
The image forming apparatus is characterized in that the intermediate layer is in contact with the guide member via the conductive member.
It has a fuser that fixes the developer image transferred to the recording medium.
The fuser is
A rotatable endless fixing member and
A guide member that comes into contact with the end face of the fixing member,
Have,
The fixing member is
The surface layer that comes into contact with the recording medium,
The elastic layer inside the surface layer and
An intermediate layer disposed between the surface layer and the elastic layer,
On the opposite side of the intermediate layer with respect to the elastic layer of the fixing member laminated in the order of the elastic layer, the intermediate layer, and the surface layer, a metal base material in contact with the guide member is provided.
Have,
The guide member contains a conductive member and has a conductive member.
The intermediate layer contains a conductive member and has a conductive member.
A conductive member having conductivity and conducting conduction between the intermediate layer and the metal base material is injected into the penetrating portion formed in the elastic layer.
An image forming apparatus characterized in that the intermediate layer and the guide member are in contact with each other. In the image forming apparatus according to claim 2,
The image forming apparatus, wherein the penetrating portion is a groove formed in the elastic layer. In the image forming apparatus according to claim 1,
The guide member has an inclined portion having conductivity formed on the side surface on the fixing member side.
An image forming apparatus characterized in that the inclined portion and the intermediate layer are in contact with each other on an inclined surface with respect to the stacking direction of the fixing member. The image forming apparatus according to any one of claims 1 to 4.
The fixing device is an image forming apparatus characterized in that a developer image transferred to a continuous recording medium is fixed. The image forming apparatus according to any one of claims 1 to 5.
An image forming apparatus characterized in that the content of the conductive member in the intermediate layer is 10% by weight or more and 20% by weight or less.

Images