JP2012103527A - Conveyance guide device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conveyance guide device able to prevent image disturbance when a recording material is conveyed from a transfer part to a fixing part, by restraining surface potential increase of a conveyance guide member, which results from paper passage.SOLUTION: The conveyance guide device 30 provided in an image forming apparatus for forming an image by fixing a toner image, transferred to a recording material by the transfer section, by use of the fixing section and is provided to guide the conveyance of the recording material after the transfer of the toner image and convey the recording material to the fixing nip of the fixing section has at least one or more conveyance guide members 31, which are provided with an ultrasonic vibration generator 50 for applying ultrasonic vibration to the conveyance guide member 31, thereby reducing a frictional coefficient of the surface. The vibrating surface remarkably decreases its frictional coefficient by ultrasonically vibrating the conveyance guide member. Therefore, even when the recording material and conveyance guide member contact during the conveyance, contact pressure decreases, making it difficult to cause frictional electrification and a surface potential increase, thus enabling the prevention of image disturbance when the recording material is conveyed in a process after post-transfer to pre-fixing.

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus such as a copying machine, a printer, a facsimile machine, or a multifunction machine having these functions, and more specifically, between a transfer part of a toner image to a recording material and a fixing part. The present invention relates to a transport guide device disposed and an image forming apparatus including the transport guide device.

  In an electrophotographic image forming apparatus, a toner image formed on an image carrier (photoreceptor or intermediate transfer member) through an electrophotographic process is transferred to a recording material such as paper (standard plain paper, postcard) by a transfer device at a transfer unit. , Thick paper, thin paper, OHP sheet, etc.), but after the transfer, the toner image is electrostatically attached to the recording material and conveyed to the fixing device of the fixing unit, and the toner image is fixed to the recording material by the fixing device. To do. Therefore, at least one conveyance guide member exists between the transfer unit and the fixing unit, and the recording material is installed so as to reach the fixing nip. While the recording material after transfer is being conveyed via the conveying member, the toner image may be disturbed if a large difference occurs between the surface potential of the conveying guide member and the toner charge on the recording material. A medium resistance or high resistance material is used on the surface of the guide member.

  Patent Document 1 (Japanese Patent Laid-Open No. 2009-237522) prevents the occurrence of image disturbance due to the recent increase in types of transfer paper, and prevents abnormal images such as transfer paper stains due to scattered toner. For this purpose, a transfer paper transport guide for a transfer apparatus, comprising: a transfer outlet guide member whose surface is an intermediate resistance or insulating portion; and a rotating rib that projects from the surface of the transfer outlet guide member to guide the transport of the transfer paper. In the plate, a configuration is disclosed in which at least a portion of the rotating rib that contacts the transfer paper is made of a conductive material and is grounded via a resistor.

  Since the conventional conveyance guide member has a high surface material resistance, the surface potential of the conveyance guide member may increase every time the number of sheets passes due to frictional charging caused by contact between the recording material and the conveyance guide member. The rise in surface potential varies depending on the friction coefficient, electrical resistance value, transfer current value, and charge removal method between the recording material and the conveying guide member surface. As the surface potential rises, the toner image on the recording material will eventually be disturbed. There was a problem that it occurred. Further, even in the conventional technique described in Patent Document 1 described above, the problem of an increase in the surface potential of the transport guide member cannot be solved.

  The present invention has been made in view of the above circumstances, and by applying ultrasonic vibration to the conveyance guide member to reduce the coefficient of friction with the recording material, it is possible to suppress an increase in surface potential due to paper passing and transfer. The image forming apparatus includes a conveyance guide device capable of preventing image disturbance when the recording material is conveyed from the fixing portion to the fixing portion, and an image formation capable of preventing the occurrence of an abnormal image due to the image disturbance. An object is to provide an apparatus.

In order to achieve the above object, the present invention employs the following solutions.
According to a first aspect of the present invention, there is provided an image forming method in which a toner image formed on an image carrier is transferred to a recording material by a transfer unit, and the toner image transferred to the recording material is fixed by a fixing unit to form an image. A conveyance guide device provided in the apparatus for guiding conveyance of the recording material after transfer of a toner image and conveying the recording material to a fixing nip of the fixing unit includes at least one conveyance guide member, An ultrasonic generator for reducing the surface friction coefficient by applying ultrasonic vibration to the guide member is provided (claim 1).

According to a second solving means of the present invention, in the transport guide apparatus of the first solving means, a standing wave of ultrasonic vibration is generated on the transport guide member by the ultrasonic generator. Item 2).
The third solving means of the present invention is characterized in that, in the conveyance guide device of the second solving means, the phase of the standing wave can be changed (claim 3).

According to a fourth solution means of the present invention, in the conveyance guide device according to the third solution means, the conveyance guide member is divided into regions in the conveyance direction.
The fifth solving means of the present invention is characterized in that, in the conveyance guide device of the fourth solving means, standing waves in adjacent areas of the conveyance guide member do not have the same phase (Claim 5).

The sixth solving means of the present invention is characterized in that, in the conveyance guide device of the fifth solving means, the vibration output of the ultrasonic generator is controlled according to the position of the conveyance path.
According to a seventh aspect of the present invention, in the conveyance guide device of the fifth aspect, the vibration output of the ultrasonic generator is controlled according to the type of the recording material. ).

According to an eighth aspect of the present invention, in the conveyance guide device according to the sixth or seventh aspect, the ultrasonic wave generator includes a surface potential measurement device that measures a surface potential of a sheet passing surface of the conveyance guide member. Is controlled based on the measurement result of the surface potential by the surface potential measuring device (claim 8).
According to a ninth solving means of the present invention, in the conveying guide device of any one of the first to eighth solving means, the conveying guide member is arranged in all of the recording material conveying path between the transfer portion and the fixing portion. (Claim 9).

  The tenth solving means of the present invention is an image forming apparatus for transferring a toner image formed on an image carrier to a recording material by a transfer unit and fixing the toner image transferred to the recording material by a fixing unit to obtain an image. The recording material conveyance path between the transfer unit and the fixing unit includes a conveyance guide device of any one of the first to ninth solving means (claim 10).

  In the conveyance guide device of the first solution means, there is provided an ultrasonic generator that has at least one conveyance guide member and applies ultrasonic vibration to the conveyance guide member to reduce the coefficient of friction of the surface. When ultrasonic vibration is generated in the conveyance guide member, the friction coefficient of the vibrating surface is significantly reduced. Therefore, even if the recording material and the conveyance guide member come into contact with each other during conveyance, the contact pressure becomes small, and frictional charging is not caused. Since it is difficult to occur and the surface potential is unlikely to rise, it is possible to prevent image disturbance when the recording material is conveyed from after transfer to before fixing.

In the conveyance guide device of the second solution means, in addition to the effects of the first solution means, the ultrasonic wave generation device generates a standing wave of ultrasonic vibrations on the conveyance guide member, thereby reducing the foot of the standing wave. Since the recording material contacts with the recording material at the position, the recording material always comes into contact with the recording material, and there is an effect that the behavior of the recording material is different for each sheet and the conveyance quality does not vary.
Further, in the conveyance guide device of the third solution means, in addition to the effect of the second solution means, the phase of the standing wave can be changed, so that the standing wave makes contact with the recording material at the same position. An effect is obtained in that a local rise in the surface potential can be prevented by changing the position of the leg of the standing wave.

In the conveyance guide device of the fourth solution means, in addition to the effect of the third solution means, the conveyance guide member is divided in the conveyance direction so that the surface area of the sheet passing surface of the conveyance guide member is large. There is a possibility that the amplitude of the standing wave does not become uniform in the conveyance direction, and the contact pressure unevenness may occur, but the effect of preventing this can be obtained.
Further, in the conveyance guide device of the fifth solution means, in addition to the effect of the fourth solution means, the standing wave of the adjacent region of the conveyance guide member is not in phase, so that the position of the leg of the standing wave is adjusted. By shifting in the transport direction, an effect of preventing the recording material being transported from being wavy is obtained.

In the conveyance guide device of the sixth solution means, in addition to the effect of the fifth solution means, by controlling the vibration output of the ultrasonic generator according to the position of the conveyance path, depending on the conveyance layout, the recording material and the conveyance guide Since the member may be divided into a portion where the member is in strong contact and a portion where the member is not in strong contact with each other, an effect that the surface potential difference in the conveyance path can be suppressed by increasing the vibration output in the region where the member is in strong contact is obtained.
Further, in the conveyance guide device of the seventh solution means, in addition to the effect of the fifth solution means, by controlling the vibration output of the ultrasonic generator according to the type of the recording material, the cardboard and the conveyance guide member are Since the contact pressure is high, the contact pressure depends on the type of recording material, such as setting the vibration output high to suppress the increase in surface potential, or reducing the vibration output to prevent paper flapping when thin paper is used. The effect that the dispersion | variation in can be suppressed is acquired.

In addition to the effects of the sixth or seventh solution means, the conveyance guide device of the eighth solution means has a surface potential measurement device that measures the surface potential of the sheet passing surface of the conveyance guide member, and vibration of the ultrasonic generator. By controlling the output based on the measurement result of the surface potential by the surface potential measuring device, it is possible to control the appropriate vibration output by detecting the surface potential of the transport guide member directly connected to the disturbance of the image being transported. The effect that it can be obtained.
In the conveyance guide device of the ninth solution means, in addition to the effect of any one of the first to eighth solution means, the conveyance guide member is arranged in all the recording material conveyance paths between the transfer unit and the fixing unit. By doing so, it is possible to prevent the image from being disturbed due to an increase in the surface potential of the conveyance guide member between the transfer portion and the fixing portion.

  In the image forming apparatus of the tenth solving means, the recording material conveyance path between the transfer section and the fixing section is provided with the conveyance guide device of any one of the first to ninth solving means, thereby causing image distortion. The generation of abnormal images due to the above can be prevented, and high-quality image formation can be performed.

FIG. 2 is a diagram illustrating an example of the present invention, and is a diagram illustrating a configuration example of an image forming apparatus of a tandem type intermediate transfer system. It is a figure which shows one Example of this invention, Comprising: It is a figure explaining the structural example of the conveyance guide apparatus which installed the ultrasonic generator in the conveyance guide member. It is a figure explaining the Example at the time of generating the standing wave of an ultrasonic vibration on a conveyance guide member. It is a figure explaining the Example in the case of changing the phase of the standing wave generated in the conveyance guide member. It is a figure explaining the Example in case a conveyance guide member is divided | segmented for every area | region in the conveyance direction. It is a figure explaining the Example in the case of controlling the vibration output by measuring the surface potential of a conveyance guide member.

Hereinafter, embodiments of the present invention will be described in detail.
According to the present invention, in the conveyance guide member installed from after the transfer in the image forming apparatus to before the fixing, the surface potential of the conveyance guide member increases due to frictional charging with the recording material every time the sheet passes, and the image is transferred to the recording material. The following features are provided for solving the problem that the image is disturbed.
In the present invention, a toner image formed on an image carrier (photosensitive member or intermediate transfer member) is transferred to a recording material by a transfer unit, and the toner image transferred to the recording material is fixed by a fixing unit to form an image. In a conveyance guide device that is provided in an image forming apparatus and guides conveyance of the recording material after transfer of a toner image and conveys the recording material to a fixing nip of the fixing unit, the conveyance guide device includes at least one conveyance guide member, An ultrasonic generator for reducing the surface friction coefficient by applying ultrasonic vibration to the transport guide member is provided.
That is, in the conveyance guide device of the present invention, when an ultrasonic generator is installed and ultrasonic vibration is generated in the conveyance guide member, the friction coefficient of the vibrating surface is significantly reduced. Even if it contacts during conveyance, the contact pressure becomes small, frictional charging hardly occurs, and the surface potential is hardly increased.
The characteristics of the present invention will be described in detail below based on the illustrated embodiments.

FIG. 1 is a diagram illustrating an example of the present invention, and is a diagram illustrating a configuration example of an image forming apparatus of a tandem type intermediate transfer system.
The image forming apparatus shown in FIG. 1 is an example of a color printer in which a plurality of image forming units are arranged along an intermediate transfer member. An image reading unit (scanner) is provided above a paper discharge tray 40 of the image forming apparatus main body. If installed, it becomes a color copier configuration, and can be used as a facsimile by adding a communication function with an external line (telephone line, optical line). Further, if it is connected to a local area network (LAN), a printer, A color multifunction peripheral having functions of a copying machine, a facsimile, and a scanner is formed.

  In FIG. 1, the image forming apparatus main body is provided with an endless belt-like intermediate transfer member 6 as an image carrier at the center. This intermediate transfer body 6 has a multilayer structure, and the base layer is made of, for example, a fluororesin, PVD sheet, or polyimide resin with little elongation, and the surface is covered with a smooth coat layer such as a fluororesin. The intermediate transfer member 6 is wound around the support rollers 15, 16, 18, and 19 so as to be able to be rotated and conveyed counterclockwise in the drawing. An intermediate transfer body cleaning device 7 for removing residual toner remaining on the intermediate transfer body 6 after image transfer is provided on the left side of the support roller 19 on the left side in the drawing. On the intermediate transfer member 6 stretched between the support roller 16 and the support roller 18, four colors of yellow (Y), cyan (C), magenta (M), and black (B) are arranged along the conveyance direction. The tandem image forming apparatus is configured by arranging the image forming means side by side. An exposure device 5 is further provided below the tandem image forming apparatus.

The four image forming units described above are different in toner color used for development but have the same configuration, and are arranged around the drum-shaped photosensitive member 1 (1Y, 1C, 1M, 1B) as an image carrier. A charging device 2, a developing device 3, a primary transfer device (for example, a primary transfer roller) 17, and a photosensitive member cleaning device 4 are provided.
In each image forming means, when the image forming operation is started, each photoconductor 1 is charged by the charging device 2, and an exposure device (for example, an optical scanning method comprising a laser light source, an optical deflector, a scanning imaging optical system, etc.). An electrostatic latent image is formed on the photosensitive member by exposure according to image data from an exposure apparatus or an exposure apparatus combining an LED array and a lens array. The electrostatic latent image on each photoconductor is developed with a developer toner (yellow (Y), cyan (C), magenta (M), black (B) toner) of the developing device 3 to be a visible image. The visible image (the toner image of each color) is primary-transferred by being superimposed on the intermediate transfer member 6 by the primary transfer roller 17. After the toner image is transferred, each photoconductor 1 is subjected to removal of residual toner by the photoconductor cleaning device 4 to prepare for image formation again.

On the other hand, a secondary transfer device is provided on the opposite side of the intermediate transfer body 6 to the support roller 15 on the right side in the drawing. In the illustrated example, the secondary transfer device is composed of a secondary transfer roller 8 and a pressure member 9 that presses the secondary transfer roller 8 in the direction of the intermediate transfer body, and is provided at the lower part of the image forming apparatus main body. The toner image on the intermediate transfer body 6 is secondarily transferred to the recording material P conveyed from the paper supply bank 21.
A fixing device 10 for fixing the transferred image on the recording material is provided on the secondary transfer device. The fixing device 10 is configured by pressing a pressure roller 13 against a fixing roller 12 having a heating source therein.
The secondary transfer roller 8 of the secondary transfer device described above is also provided with a transport function for transporting the recording material after image transfer to the fixing nip of the fixing device 10. Further, a conveyance guide device 30 including a plurality of conveyance guide members 31 and 11 is installed between the secondary transfer roller 8 and the fixing nip, and the intermediate transfer body 6 is formed by the secondary transfer roller 8 of the secondary transfer device. The recording material on which the toner image is transferred is conveyed by the rotation of the secondary transfer roller, and is conveyed to the fixing nip of the fixing device 10 via the conveyance guide members 31 and 11.

  In the image forming apparatus configured as described above, when a start switch of an operation unit (operation panel) (not shown) is pressed, an image forming operation is started, and one of the support rollers 15, 16, and 19 is driven by a drive motor (not shown). One of them is driven to rotate, the other four support rollers are driven to rotate, and the intermediate transfer member 6 is rotated and conveyed. At the same time, the individual image forming means rotate the photoreceptors 1Y, 1C, 1M, and 1B to perform the above-described image formation, and each color is yellow (Y), cyan (C), magenta (M), and black (B). Form an image. Then, along with the conveyance of the intermediate transfer body 6, these single color images are sequentially transferred to form a composite color image on the intermediate transfer body 6.

  On the other hand, paper feed cassettes 22 (in the figure, recording materials of different sizes (standard recording papers such as B5, A4, B4, A3, etc.) provided in multiple stages in the paper feed bank 21 in time with the above image forming operation. One of the housed paper feed cassettes 22 is installed in the upper and lower stages), the paper feed roller 23 of the selected paper feed cassette 22 is rotated, the recording material P is fed out, and the separation roller 24 The sheets are separated one by one and are put into the paper feed path 25, transported by the transport roller 26, guided to the paper feed path 27 in the main body of the image forming apparatus, and abutted against the registration roller 28 and stopped. Then, the registration roller 28 is rotated in time with the composite color image on the intermediate transfer body 6, and the recording material P is sent to the transfer portion between the intermediate transfer body 6 and the secondary transfer roller 8 of the secondary transfer device. Then, electrostatic transfer is performed by a secondary transfer device, and a color image is recorded on the recording material. The recording material P after image transfer is conveyed by the rotation of the secondary transfer roller 8 of the secondary transfer device, and is sent to the fixing device 10 of the fixing unit via the conveyance guide members 31 and 11 of the conveyance guide device 30. The transfer image is fixed on the recording material P by applying heat and pressure at the fixing nip where the fixing roller 12 and the pressure roller 13 of the fixing device 10 are in pressure contact, and then discharged by the discharge roller 39 and placed on the discharge tray 40. Stack.

  On the other hand, the intermediate transfer body 6 after the image transfer is removed by the intermediate transfer body cleaning device 7 to remove residual toner remaining on the intermediate transfer body 6 after the image transfer, and is prepared for re-image formation by the tandem image forming apparatus.

Next, a description will be given of an embodiment of the conveyance guide device provided in the image forming apparatus having the configuration as shown in FIG.
FIG. 2 is a diagram illustrating an embodiment of the present invention, and is a diagram illustrating a configuration example of a conveyance guide device in which an ultrasonic generator is installed on a conveyance guide member.
In the illustrated example, a configuration example is shown in which the ultrasonic wave generation device 50 causes ultrasonic vibration to the transport guide member 31 disposed on the outlet side of the transfer unit of the secondary transfer device. The generator 50 is installed on the back side of the sheet passing surface of the conveyance guide member 31. Further, in order to generate ultrasonic vibration on the sheet passing surface of the conveyance guide member 31, the ultrasonic generator 50 needs to be bonded or fastened to the conveyance guide member 31.

  As an ultrasonic generation source of the ultrasonic generator 50, a piezoelectric element 51 such as PZT is used. When the piezoelectric element 51 is sandwiched between two electrode plates 52 and an AC voltage is applied at a frequency in the ultrasonic region, the piezoelectric element 51 is ultrasonically vibrated. The piezoelectric element 51 has a polarity direction 53. When a positive (+) DC voltage is applied in that direction, the piezoelectric element 51 expands, and when a negative (-) DC voltage is applied, the piezoelectric element 51 contracts. is there. Since the ultrasonic vibration itself has a short vibration cycle and very small vibration and amplitude, the material and size of the member are such that the resonance frequency of the member combining the conveyance guide member 31 and the ultrasonic generator 50 becomes the driving frequency of the ultrasonic region. Now, it is necessary to determine the shape. In addition, since the resonance frequency may fluctuate due to changes in the rigidity of the conveyance guide member 31 due to variations in solids or environmental variations, the AC voltage application device V1 provided in the ultrasonic generator 50 has a frequency adjustment function. .

FIG. 3 is a diagram for explaining an embodiment in the case where a standing wave of ultrasonic vibration is generated in the transport guide member.
The piezoelectric element 51 serving as the ultrasonic wave generation source of the ultrasonic generator 50 is divided into a plurality of pieces in the axial direction, and arranged so that the polar directions 53 of the adjacent piezoelectric elements 51 are opposite to each other. A standing wave can be generated on the surface of the conveyance guide member 31 along with the application. However, in the member in which the conveyance guide member 31 and the ultrasonic generator 50 are combined, the resonance frequency of the vibration mode having the target wave number needs to exist in the ultrasonic region.

  When a standing wave of ultrasonic vibration is generated in the conveyance guide member 31, the position of the node does not vibrate, and the vibration amplitude is maximized at the foot position 54. Therefore, the conveyance guide member 31 is mainly located at the foot position. At 54, the recording material P comes into contact. Therefore, the recording material P always comes into contact with the conveyance guide member 31 at the same position, and the behavior of the recording material P being conveyed is less likely to change every time a sheet is passed.

  As described above, in this embodiment, the standing wave of the ultrasonic vibration is generated on the conveyance guide member 31 to contact the recording material P at the foot position 54 of the standing wave. In other words, the behavior of the recording material differs from sheet to sheet, and there is no variation in the conveyance quality.

  As for the direction of the standing wave, the standing wave is generated in the axial direction in the illustrated example, but the standing wave may be generated in the conveying direction. However, assuming that the phase of the standing wave is changeable, and the phase of the standing wave is changed, the position where the conveyance guide member 31 and the recording material come in contact changes depending on the conveyance direction. There is a risk of variations in the recording material slack.

FIG. 4 is a diagram for explaining an embodiment in the case where the phase of the standing wave generated in the transport guide member is changed.
When a standing wave is generated in the conveyance guide member 31, the recording material P comes into contact only at the position 54 of the standing wave foot. There is a risk that the surface potential of the transport guide member 31 may increase. Therefore, the phase of the standing wave is periodically changed so that the recording material P comes into contact only at a specific position of the transport guide member 31.

  In the illustrated example, the ultrasonic generator 50 has a piezoelectric element that is shifted in the axial direction by the phase that is to be shifted with respect to the adjacent piezoelectric element 51 with opposite polarities as a configuration necessary for changing the phase of the standing wave. Another set of the elements 51 is installed, and when the phase changes, the former piezoelectric element is switched from the former piezoelectric element by a changeover switch or the like, and the AC voltage is applied by the AC voltage applying device V1, thereby making the constant. The position 54 of the standing wave foot changes, and the contact point with the recording material P changes.

  As described above, in this embodiment, since the phase of the standing wave can be changed, the standing wave makes contact with the recording material at the same position. It prevents local rise.

FIG. 5 is a diagram illustrating an example in which the conveyance guide member is divided for each region in the conveyance direction.
In the example of FIG. 5A, the conveyance guide member is divided into several regions in the conveyance direction, and the conveyance guide members 31, 32, and 33 are formed from the upstream side in the conveyance direction. In this case, there is an advantage that the piezoelectric element 51 can be made small.

In the first place, when a uniform standing wave is generated in the conveying direction, when a recording material P having a weak stiffness such as thin paper is passed, the shape of the standing wave is changed, and the wave is undulated in the axial direction. The recording material may be conveyed to the fixing.
Therefore, as shown in FIG. 5A, the conveyance guide member is divided into a plurality of regions in the conveyance direction to form conveyance guide members 31, 32, 33, and particularly as shown in the waveform diagram of FIG. The above-mentioned problem can be solved by making the phase of the standing wave not to be the same as that of the matching guide member. In this case, it is necessary to have AC voltage application devices (AC power supplies) V1, V2, and V3 for the divided conveyance guide members 31, 32, and 33, respectively.

  As described above, in this embodiment, the standing waves in the adjacent areas of the conveyance guide members 31, 32, and 33 are not in phase, so that the position of the standing wave foot is shifted in the conveyance direction and is being conveyed. It is possible to prevent the recording material from becoming wavy.

  Note that, in the case of the above configuration, especially for the conveyance layout in which the recording material is in strong contact, the control is such that the vibration output of the ultrasonic generator 50 is increased in the area where the recording material is in strong contact, or the vibration output is decreased in the area where there is little contact. Is provided. Specifically, individual voltage settings can be made for the AC voltage application devices (AC power supplies) V1, V2, and V3 that apply an AC voltage to the ultrasonic generator 50 in each region. As a result, a local increase in surface potential of the transport guide members 31, 32, 33 can be suppressed, and wasteful consumption of power consumption can be prevented.

  As described above, in this embodiment, by controlling the vibration output of the ultrasonic generator 50 according to the position of the transport path, depending on the transport layout, the recording material and the transport guide member may be in strong contact with each other. Since there is a case where it is divided, the difference in the surface potential in the transport path can be suppressed by increasing the vibration output in the strongly contacting region.

In this embodiment, the vibration output of the ultrasonic generator 50 is controlled by controlling the AC voltage application devices (AC power supplies) V1, V2, and V3 according to the paper type information of the recording material to be passed such as thick paper and thin paper. Provide a function to control. As a result, even when various types of recording materials are passed through, it is possible to prevent the surface potential from becoming unpredictable due to contact with the conveyance guide members 31 to 33 with an appropriate contact pressure.
That is, in this embodiment, by controlling the vibration output of the ultrasonic generator 50 according to the type of recording material, the contact pressure with the conveyance guide member is high for cardboard, so the vibration output is set high and the surface potential is set. The variation in the contact pressure depending on the type of recording material can be suppressed, such as suppressing the increase of the recording material or reducing the vibration output when the paper is thin so as not to flutter the paper.

FIG. 6 is a diagram for explaining an embodiment in which the surface potential of the conveyance guide member is measured to control the vibration output.
As shown in FIG. 6, a detection member 61 that measures the surface potential of the transport guide member 31 is provided in contact with the sheet passing surface of the transport guide member 31, and the sheet potential surface of the transport guide member 31 is periodically provided by the surface potential measuring device 60. Is stored in the storage device 62 (usually a storage device provided in the control unit of the image forming apparatus is used together, but a memory such as a nonvolatile RAM may be provided separately). Thus, the accuracy of the vibration output control described above can be increased.

  As described above, in this embodiment, the surface potential measuring device 60 that measures the surface potential of the sheet passing surface of the transport guide member 31 is provided, and the vibration output of the ultrasonic generator 50 is measured by the surface potential measuring device 60. By controlling based on the result, an appropriate vibration output can be controlled by detecting the surface potential of the transport guide member directly connected to the disturbance of the image being transported.

  In the above-described embodiment, the configuration example in the case where the ultrasonic wave generation device 50 causes ultrasonic vibration to the conveyance guide member 31 disposed on the exit side of the transfer unit of the secondary transfer device has been described. The ultrasonic generator 50 may be installed on the conveyance guide member 11 on the side close to the fixing device 10, and further, the ultrasonic generator 50 may be superposed on all the conveyance guide members 31 and 11 in the recording material conveyance path between the transfer unit and the fixing unit. By disposing the sound wave generating device 50, it is possible to prevent image disturbance due to an increase in the surface potential of the conveyance guide members 31 and 11 between the transfer portion and the fixing portion.

  In the image forming apparatus of this embodiment shown in FIG. 1, the abnormal image due to image disturbance is provided by providing the conveyance guide device 30 of each of the above embodiments in the recording material conveyance path between the transfer section and the fixing section. Can be prevented, and high-quality image formation can be performed.

1 (1Y, 1C, 1M, 1B): photoconductor (image carrier)
2: Charging device 3: Developing device 4: Photoconductor cleaning device 5: Exposure device 6: Intermediate transfer member (image carrier)
7: Intermediate transfer member cleaning device 8: Secondary transfer roller (secondary transfer device)
9: Pressure member 10: Fixing device 11: Conveying guide member 12: Fixing roller 13: Pressure roller 15, 16, 18, 19: Support roller 17: Primary transfer roller (primary transfer device)
21: Paper supply bank 22: Paper supply cassette 23: Paper supply roller 24: Separation roller 26: Conveyance roller 28: Registration roller 30: Conveyance guide device 31, 32, 33: Conveyance guide member provided with an ultrasonic generator 39: Paper discharge roller 40: Paper discharge tray 50: Ultrasonic generator 51: Piezoelectric element P: Recording material V1, V2, V3: AC voltage application device (AC power supply)

JP 2009-237522 A

Claims (10)

A toner image formed on an image carrier is transferred to a recording material by a transfer unit, and the toner image transferred to the recording material is fixed by a fixing unit to form an image. In a conveyance guide device that guides conveyance of the recording material and conveys the recording material to a fixing nip of the fixing unit,
A conveyance guide device comprising at least one conveyance guide member, and an ultrasonic generator for reducing the friction coefficient of the surface by applying ultrasonic vibration to the conveyance guide member. In the conveyance guide device according to claim 1,
A conveyance guide device characterized in that a standing wave of ultrasonic vibration is generated in the conveyance guide member by the ultrasonic wave generation device. In the conveyance guide device according to claim 2,
The conveyance guide apparatus characterized in that the phase of the standing wave can be changed. In the conveyance guide device according to claim 3,
The conveyance guide apparatus characterized in that the conveyance guide member is divided in the conveyance direction. In the conveyance guide device according to claim 4,
A conveyance guide device, wherein standing waves in adjacent areas of the conveyance guide member do not have the same phase. In the conveyance guide device according to claim 5,
A conveyance guide apparatus that controls vibration output of the ultrasonic generator according to a position of a conveyance path. In the conveyance guide device according to claim 5,
A conveyance guide device that controls vibration output of the ultrasonic generator according to the type of the recording material. In the conveyance guide apparatus of Claim 6 or Claim 7,
It has a surface potential measuring device for measuring the surface potential of the sheet passing surface of the conveyance guide member, and the vibration output of the ultrasonic generator is controlled based on the measurement result of the surface potential by the surface potential measuring device. A conveyance guide device. In the conveyance guide apparatus as described in any one of Claims 1-8,
A conveyance guide device, wherein the conveyance guide member is disposed in all of a recording material conveyance path between a transfer unit and a fixing unit. In an image forming apparatus in which a toner image formed on an image carrier is transferred to a recording material by a transfer unit, and the toner image transferred to the recording material is fixed by a fixing unit to obtain an image.
An image forming apparatus comprising the conveyance guide device according to claim 1 in a recording material conveyance path between the transfer unit and the fixing unit.

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