JP2004284723A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of discharging a transfer material on which a toner image is transferred to a proper degree without complicating the designing and manufacturing processes of the apparatus and precluding occurrence of a jam, hindrance of the transfer material from smooth transport, and a deterioration in the image quality resulting from a turbulence in the unfixed toner image. <P>SOLUTION: The image forming apparatus is structured so that a conductive fiber member is installed downstream in the transfer material transporting direction of a discharging means in such a way as confronting and contacting with the non-image forming surface of the transfer material. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming apparatus such as a printer, a copying machine, or a facsimile that employs an electrophotographic method, and is particularly suitable for an image forming apparatus that transfers a developed image formed on an image carrier onto a transfer material. The present invention relates to a static elimination technology that can be applied to a device.
[0002]
[Patent Document 1] JP-A-2001-278486
[0003]
[Prior art]
Conventionally, in an image forming apparatus such as a printer, a copying machine, a facsimile or the like that adopts this type of electrophotographic method, a toner visible image formed on a photosensitive drum is transferred onto a transfer material such as paper. Then, a predetermined charge is supplied from the non-image forming surface side of the sheet, and the toner visible image is transferred to the sheet side by utilizing the electrostatic attraction by the charge on the back side of the sheet. Then, in the image forming apparatus, after the toner visible image is transferred to the sheet, the electric charges accumulated on the sheet affect the sheet jam and prevent the sheet from being transported smoothly. In order to prevent the above problem, a static eliminator for moderately eliminating charges accumulated on the sheet from the non-image forming side of the sheet is used.
[0004]
Such a static eliminator usually needs to be grounded to release electric charges. However, since the design and manufacturing process of the image forming apparatus are complicated, a conductive fiber member that does not need to be grounded is neutralized. It has already been proposed to use
[0005]
An image forming apparatus using the conductive fiber member is disclosed in, for example, JP-A-2001-278486. The technology disclosed in Japanese Patent Application Laid-Open No. 2001-278486 enables smooth paper transport by stably removing charges accumulated on paper immediately after transferring toner, and enables high-quality printing. In order to provide an image forming apparatus capable of obtaining an image, an electrostatic latent image carrier, transfer means for transferring a developer supplied on the electrostatic latent image carrier onto a transfer material, and the transfer material And a charge eliminator provided on the downstream side of the transfer unit in the transfer path for removing charges accumulated in the transfer material, wherein the charge eliminator comprises a non-image forming unit for the transfer material. A conductive member provided at a position facing the surface, and a conductive fiber member provided on the opposite side of the transfer material across the conductive member and electrically connected to the conductive member, Be prepared Are those that form.
[0006]
[Problems to be solved by the invention]
However, the prior art has the following problems. That is, in the case of the image forming apparatus disclosed in Japanese Patent Application Laid-Open No. 2001-278486, the static elimination means includes a conductive member provided at a position facing the non-image forming surface of the transfer material; A conductive fiber member provided on the opposite side of the transfer material with the member interposed therebetween, and electrically connected to the conductive member, and electrically connected to the conductive member. The conductive fiber member is in a non-contact state with the transfer material. Therefore, when applied to a color image forming apparatus that repeats the toner image transfer process a plurality of times, the voltage applied to the transfer material for transferring the toner image is a voltage that is significantly higher than that of a monochrome machine, In a combination of a conductive member and a conductive fiber member that are not in contact with the transfer material, the non-image forming surface side of the transfer material cannot be sufficiently discharged, and the charge accumulated on the transfer material cannot be removed. As a result, there is a problem that it is not possible to prevent the occurrence of a jam, to prevent the smooth conveyance of the transfer material, or to prevent the unfixed toner image from being disturbed.
[0007]
Also, if the charge accumulated in the transfer material is excessively removed by, for example, grounding the conductive fiber member, the charge balance between the front and back surfaces of the transfer material is lost, and the charge is formed on the transfer material. There is another problem that the toner image is disturbed and the image quality is deteriorated.
[0008]
Therefore, the present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to transfer a toner image without complicating the design and manufacturing process of an image forming apparatus. The transfer material can be appropriately neutralized to prevent jamming, hindering smooth transfer of the transfer material, and disturbing the unfixed toner image, thereby deteriorating the image quality. To provide an image forming apparatus capable of performing the following.
[0009]
[Means for Solving the Problems]
In order to solve the above-described problem, the invention according to claim 1 includes: at least one latent image carrier on which a toner image is formed on a surface; and a toner image formed on a surface of the latent image carrier. A transfer unit for transferring directly onto the transfer material via at least one intermediate transfer body, and a charge removing unit provided downstream of the transfer unit in the transfer material transport direction for removing electric charges accumulated in the transfer material. An image forming apparatus comprising: an image forming apparatus, wherein a conductive fiber member is disposed downstream of the charge removing unit in a transfer material transport direction so as to face and contact a non-image forming surface of the transfer material. It is.
[0010]
The invention described in claim 2 is the image forming apparatus according to claim 1, wherein only the leading end of the conductive fiber member contacts the non-image forming surface of the transfer material. .
[0011]
The image forming apparatus according to claim 1, wherein the conductive fiber member comes into contact with the non-image forming surface of the transfer material with a certain contact width from a tip end thereof. Device.
[0012]
According to a fourth aspect of the present invention, the conductive fiber member has a tip portion divided into a plurality of portions along a direction perpendicular to the transfer material transport direction. An image forming apparatus.
[0013]
Further, the invention described in claim 5 is characterized in that the conductive fiber member is formed with irregularities continuously at a tip end thereof in a direction orthogonal to the transfer material transport direction. 1 is an image forming apparatus.
[0014]
The invention described in claim 6 is the image forming apparatus according to claim 1, wherein the conductive fiber member is not electrically grounded.
[0015]
Further, according to the present invention, a plurality of latent image carriers each having a toner image of a different color formed on the surface thereof, a transfer material transport member for transporting a transfer material, and the plurality of latent image bearing members are provided. And a plurality of transfer means for transferring a toner image formed on the surface of the body in a multiplex manner onto a transfer material conveyed by the transfer material conveying member. An image forming apparatus, wherein a conductive fiber member is disposed downstream of each transfer unit in the transfer material transport direction so as to face and contact the inner surface of the transfer material transport member.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described below with reference to the drawings.
[0017]
Embodiment 1
FIG. 2 shows a tandem-type full-color printer as an image forming apparatus according to Embodiment 1 of the present invention.
[0018]
In FIG. 2, reference numeral 01 denotes a main body of a tandem type full-color printer. Inside the printer main body 01, a print head device (Print Head Device) 02 for forming a full-color image and a print head device 02 are provided. ROS (Raster Output Scanner) 03 as an exposure device for exposing four photosensitive drums 11, 12, 13, and 14 as latent image carriers of the head device 02, and developing devices of each color of the print head device 02 Four toner boxes 04Y, 04M, 04K, and 04C for supplying toners of colors corresponding to 41, 42, 43, and 44, and transfer material storage means for supplying transfer paper P as a transfer material to the print head device 02. Paper tray 05 and the above print A fixing device 06 that performs a fixing process on the transfer paper P on which the toner image has been transferred from the head device 02 and a transfer paper P on which an image is fixed on one side by the fixing device 06 are turned upside down. A double-sided conveyance path 07 for conveying the sheet again to the transfer section of the print head device 02, a manual sheet feeding unit 08 for feeding a desired transfer sheet P from outside the printer main body 01, a control circuit for controlling the operation of the printer, A controller 09 including an image processing circuit for performing image processing on an image signal and an electric circuit 10 including a high-voltage power supply circuit are provided. In FIG. 2, T indicates a discharge toilet that discharges the transfer paper P on which an image has been formed, and the discharge toilet T is integrally disposed on the upper portion of the printer main body 01.
[0019]
Of the various members disposed inside the printer main body 01, ROS03 as an exposure device is a type of image data corresponding to each color of yellow (Y), magenta (M), black (K), and cyan (C). Semiconductor lasers driven on the basis of the laser beam, four laser beams emitted from these four semiconductor lasers, an f-θ lens, a polygon mirror, or a plurality of reflection mirrors for deflecting and scanning. It is configured.
[0020]
FIG. 3 shows a print head device of a tandem-type full-color printer as an image forming apparatus according to Embodiment 1 of the present invention. The arrows in FIG. 3 indicate the rotation direction of each rotating body.
[0021]
As shown in FIG. 3, the print head device 02 includes photosensitive drums (latent image carriers) 11, 12, and 13 for yellow (Y), magenta (M), black (K), and cyan (C). , 14, and charging rolls (contact-type charging devices) 21, 22, 23, 24 for primary charging that contact the photosensitive drums 11, 12, 13, 14. Refresher rolls 25, 26, 27, 28 for temporarily removing toner remaining on the surfaces of the photosensitive drums 11, 12, 13, 14, 14, yellow (Y), magenta (M), black (K), An ROS (exposure device) 03 for irradiating laser light 31, 32, 33, 34 of each color of cyan (C) and an electrostatic latent image formed on the photosensitive drums 11, 12, 13, 14 are converted into yellow. ( ), Magenta (M), black (K), and cyan (C), and developing devices 41, 42, 43, and 44, among the four photosensitive drums 11, 12, 13, and 14. A first primary intermediate transfer drum (intermediate transfer member) 51 in contact with the two photosensitive drums 11 and 12 and a second primary intermediate transfer drum (intermediate transfer member) in contact with the other two photosensitive drums 13 and 14 52, a secondary intermediate transfer drum (intermediate transfer body) 53 that contacts the first and second primary intermediate transfer drums 51 and 52, and a final transfer roll (transfer unit) that contacts the secondary intermediate transfer drum 53 60 constitutes the main part. On the surfaces of the intermediate transfer drums 51, 52, 53, cleaning rolls 54, 55, 56 of a cleaning device for removing toner remaining on the surfaces of the intermediate transfer drums 51, 52, 53 are provided. .
[0022]
As the photosensitive drums 11, 12, 13, and 14, known photosensitive drums are used, and a photosensitive layer is formed around a conductive pipe. As a material of the conductive pipe, for example, a metal such as SUS, Al, or the like, on which metal such as Al or CU is deposited or plated, or a conductive plastic in which conductive powder or filler such as metal or carbon is mixed. Are used. Further, as the photosensitive layer, an inorganic photoreceptor such as Se, Cds, α-Si, or an organic photoreceptor having a multilayer structure can be used. In this embodiment, the photoconductor drums 11, 12, 13, and 14 are each formed by coating a surface of an Al pipe having a diameter of 30 mm with a multilayer organic photoconductor.
[0023]
The photoconductor drums 11, 12, 13, 14 are arranged in parallel to each other at a predetermined interval so as to have a common tangent plane M. Further, the first primary intermediate transfer drum 51 and the second primary intermediate transfer drum 52 have surfaces whose rotation axes are parallel to the photosensitive drums 11, 12, 13, and 14 and whose boundary is a predetermined symmetry plane. They are arranged in a symmetrical relationship. Further, the secondary intermediate transfer drum 53 is disposed so that the rotation axis is parallel to the photosensitive drums 11, 12, 13, and 14.
[0024]
A signal corresponding to the image information for each color is rasterized by an image processing circuit provided in the electric circuit 10 (see FIG. 2) and input to the ROS 03. In the ROS03, laser beams 31, 32, 33, and 34 of yellow (Y), magenta (M), black (K), and cyan (C) are modulated, and the photosensitive drums 11, 12, and 13 of corresponding colors are modulated. 13 and 14 are irradiated.
[0025]
Around each of the photosensitive drums 11, 12, 13, and 14, an image forming process for each color is performed by a known electrophotographic method. First, as the photoconductor drums 11, 12, 13, and 14, for example, photoconductor drums using an OPC photoconductor having a diameter of 30 mm are used, and these photoconductor drums 11, 12, 13, and 14 will be described later. The driving device of the rotating body is driven to rotate at a rotation speed (peripheral speed) of, for example, 104 mm / sec. As shown in FIG. 3, the surfaces of the photosensitive drums 11, 12, 13, and 14 are applied to charging rolls 21, 22, 23, and 24 as contact-type charging devices by applying a DC voltage of about -840V. , For example, about -300V. The contact-type charging device includes a roll-type charging device, a film-type charging device, and a brush-type charging device, but any type may be used. In this embodiment, a charging roll generally used in an electrophotographic apparatus in recent years is employed. Further, in this embodiment, in order to charge the surfaces of the photosensitive drums 11, 12, 13, and 14, a charging method in which only DC is applied is employed, but a charging method in which AC + DC is applied may be used. .
[0026]
Thereafter, laser light 31 corresponding to each color of yellow (Y), magenta (M), black (K), and cyan (C) is applied to the surfaces of the photosensitive drums 11, 12, 13, and 14 by ROS03 as an exposure device. , 32, 33, and 34, and an electrostatic latent image corresponding to the input image information for each color is formed. When the electrostatic latent image is written by the ROS 03, the surface potential of the image exposed portion of the photosensitive drums 11, 12, 13, and 14 is removed to about -60 V or less.
[0027]
The electrostatic latent images corresponding to the colors of yellow (Y), magenta (M), black (K), and cyan (C) formed on the surfaces of the photosensitive drums 11, 12, 13, and 14, respectively, Of the yellow (Y), magenta (M), black (K), and cyan (C) on the photosensitive drums 11, 12, 13, and 14, respectively. It is visualized as a toner image.
[0028]
In this embodiment, a magnetic brush contact type two-component developing system is employed as the developing devices 41, 42, 43, and 44. However, the scope of the present invention is not limited to this developing system. Of course, the present invention can be sufficiently applied to a non-contact type developing system.
[0029]
The developing devices 41, 42, 43, and 44 are filled with yellow (Y), magenta (M), black (K), and cyan (C) toners of different colors and a developer composed of a carrier. I have. As shown in FIG. 2, when the toner and the developer are supplied from the toner boxes 04Y, 04M, 04K, and 04C of the corresponding colors to the developing devices 41, 42, 43, and 44, the supplied toner is supplied. The developer and the developer are sufficiently stirred by the augers 401 and 402 with the developer in the developing devices 41, 42, 43 and 44, and are triboelectrically charged. Inside the developing roll 403, a magnet roll (not shown) having a plurality of magnetic poles arranged at a predetermined angle is arranged in a fixed state. The amount of the developer conveyed to the vicinity of the surface of the developing roll 403 by the auger 402 that conveys the developer to the developing roll 403 is regulated by the developer amount regulating member 404 to the amount conveyed to the developing section. In this embodiment, the amount of the developer is 30 to 50 g / m2. ² Further, at this time, the charge amount of the toner present on the developing roll 403 is approximately -20 to 35 μC / g.
[0030]
The toner supplied onto the developing roll 403 is in the form of a magnetic brush composed of a carrier and toner due to the magnetic force of the magnet roll, and the magnetic brush comes into contact with the photosensitive drums 11, 12, 13, and 14. ing. An AC + DC developing bias voltage is applied to the developing roll 403 to develop the toner on the developing roll 403 into an electrostatic latent image formed on the photosensitive drums 11, 12, 13, and 14, thereby forming a toner image. Is formed. In this embodiment, for example, the AC component of the developing bias voltage is set to 4 kHz and 1.5 kVpp, and the DC component is set to about -230 V.
[0031]
In this embodiment, in the developing devices 41, 42, 43, and 44, a so-called “spherical toner”, which is a substantially spherical toner, having an average particle diameter of about 3 to 10 μm is used. For example, the average particle size of the black toner is set to 8 μm, and the average particle size of the color toner is set to 7 μm.
[0032]
Next, the yellow (Y), magenta (M), black (K), and cyan (C) toner images formed on the respective photosensitive drums 11, 12, 13, and 14 are first primary images. Secondary transfer is electrostatically performed on the intermediate transfer drum 51 and the second primary intermediate transfer drum 52. The yellow (Y) and magenta (M) toner images formed on the photoconductor drums 11 and 12 are formed on the first primary intermediate transfer drum 51 by the black ( The toner images of K) and cyan (C) are respectively transferred onto the second primary intermediate transfer drum 52. Therefore, on the first primary intermediate transfer drum 51, the monochrome image transferred from either of the photosensitive drums 11 and 12 and the two-color toner image transferred from both of the photosensitive drums 11 and 12 are superimposed. A double-color image is formed. Also, on the second primary intermediate transfer drum 52, similar single-color images and double-color images are formed from the photosensitive drums 13 and 14.
[0033]
The surface potential required for electrostatically transferring the toner image from the photosensitive drums 11, 12, 13, 14 onto the first and second primary intermediate transfer drums 51, 52 is about +250 to 500V. is there. The surface potential is set to an optimum value depending on the charged state of the toner, the ambient temperature, and the humidity. The ambient temperature and humidity can be easily known by detecting the resistance value of a member having a characteristic in which the resistance value changes depending on the ambient temperature and humidity. As described above, when the charge amount of the toner is in the range of −20 to 35 μC / g and is in a normal temperature and normal humidity environment, the surface potential of the first and second primary intermediate transfer drums 51 and 52 is Is preferably about + 380V.
[0034]
As the intermediate transfer member, a known one such as a belt-shaped one can be used in addition to a drum-shaped one. As the intermediate transfer belt, for example, a plastic sheet (with a thickness of about 10 μm to 100 μm) mixed with a conductive powder such as metal or carbon and a filler and adjusted in resistance value, for example, polyimide, polycarbonate, polyethylene, polyethylene terephthalate (PET) Or an alloy type. The resistance value of the intermediate transfer belt is 10 ⁶ Ω · cm-10 ¹⁴ Ω · cm is desirable. The intermediate transfer belt may have a single-layer structure or a multi-layer structure having an extremely thin dielectric layer (0.5 to 2 μm) on its surface. On the other hand, as the intermediate transfer drum, for example, a drum in which a semiconductive elastic body (a material example is described in JP-A-8-334995) is coated around a conductive core like the photosensitive drum. Can be used.
[0035]
The first and second primary intermediate transfer drums 51 and 52 used in this embodiment have, for example, an outer diameter of 60 mm and an overall resistance of 10 mm. ⁹ It is set to about Ω. Each of the first and second primary intermediate transfer drums 51 and 52 is a single-layer or multiple-layer cylindrical rotating body having a flexible or elastic surface, and is generally made of Fe, Al, or the like. A low resistance elastic rubber layer typified by conductive silicone rubber or the like is provided on a metal pipe as a metal core having a thickness of about 5 mm. Further, the outermost surfaces of the first and second intermediate transfer drums 51 and 52 are formed of a top layer coated with acrylic silicon to a thickness of 10 μm.
[0036]
The single-color or double-color toner images formed on the first and second primary intermediate transfer drums 51 and 52 in this way are electrostatically and tertiarily transferred onto the secondary intermediate transfer drum 53. Therefore, on the secondary intermediate transfer drum 53, a final toner image from a single color image to a quadruple color image of yellow (Y), magenta (M), cyan (C) and black (K) is formed. Will be done.
[0037]
The surface potential required for electrostatically transferring the toner images from the first and second primary intermediate transfer drums 51 and 52 onto the secondary intermediate transfer drum 53 is approximately +600 to 1200V. The surface potential is the same as when the toner is transferred from the photoconductor drums 11, 12, 13, and 14 to the first primary intermediate transfer drum 51 and the second primary intermediate transfer drum 52. Will be set to the optimum value. Further, since what is necessary for the transfer is the potential difference between the first and second primary intermediate transfer drums 51 and 52 and the secondary intermediate transfer drum 53, the potential difference between the first and second primary intermediate transfer drums 51 and 52 It is necessary to set a value corresponding to the surface potential. As described above, the charge amount of the toner is in the range of −20 to 35 μC / g, and the surface potential of the first and second primary intermediate transfer drums 51 and 52 is about +380 V in a normal temperature and normal humidity environment. In this case, the surface potential of the secondary intermediate transfer drum 53 is about +880 V, that is, the potential difference between the first and second primary intermediate transfer drums 51 and 52 and the secondary intermediate transfer drum 53 is about +500 V. It is desirable to set.
[0038]
The secondary intermediate transfer drum 53 used in this embodiment has, for example, an outer diameter of 60 mm, which is the same as the first and second primary intermediate transfer drums 51 and 52, and a resistance value of 10 mm. ⁹ It is set to about Ω. Similarly to the first and second primary intermediate transfer drums 51 and 52, the secondary intermediate transfer drum 53 is a cylindrical rotating body having a single-layer or multiple-layer surface with a flexible or elastic surface. In general, a low-resistance elastic rubber layer represented by conductive silicone rubber or the like is provided with a thickness of about 5 mm on a metal pipe as a metal core generally made of Fe, Al, or the like. Further, the outermost surface of the secondary intermediate transfer drum 53 is formed of a top layer coated with acrylic silicon to a thickness of 10 μm. A transfer roll 60 is pressed against the surface of the secondary intermediate transfer drum 53 so as to cut into the surface of the secondary intermediate transfer drum 53 by about 0.5 mm. A transfer nip having a concave shape on the 53 side is formed to enhance the peeling action of the transfer paper P 1.
[0039]
Next, the final toner image from the single-color image to the quadruple-color image formed on the secondary intermediate transfer drum 53 is transferred by the final transfer roll 60 onto a transfer sheet P as a transfer material passing through a sheet transport path. Is tertiarily transferred to The transfer paper P on which the final toner image has been transferred from the secondary intermediate transfer drum 53 is, as shown in FIG. 1, used as a static eliminator disposed downstream of the transfer roll 60 along the transfer paper transport direction. The charge is removed by the discharging needle 61, and the charge is removed from the secondary intermediate transfer drum 53. The static elimination needle 61 as the static elimination means is formed of a metal flat plate having a tip portion formed in a saw-like shape, and is configured such that a negative high voltage having a polarity opposite to the voltage applied to the transfer roll 60 is applied. ing. It should be noted that a corotron or the like may be used as the charge removing means. The paper P passes through a registration roll 90 through a paper feeding process (not shown), and is fed into a nip portion between the secondary intermediate transfer drum 53 and the final transfer roll 60 via a guide member 63. After the final transfer step, the transfer sheet P on which the final toner image has been transferred is transferred via a transfer material transfer chute 62 provided with a plurality of ribs extending along the transfer direction of the sheet. Is conveyed to the fixing device 06 and is fixed by heat and pressure, and a series of image forming processes is completed.
[0040]
By the way, in this embodiment, at least one latent image carrier on which a toner image is formed on the surface and the toner image formed on the surface of the latent image carrier are interposed via at least one intermediate transfer member or An image forming apparatus comprising: a transfer unit that directly transfers the image on a transfer material; and a charge removal unit that is provided downstream of the transfer unit in a transfer material transport direction and that removes charges accumulated on the transfer material. A conductive fiber member is disposed on the downstream side in the transfer material transport direction so as to face and contact the non-image forming surface of the transfer medium.
[0041]
That is, in the tandem-type full-color printer according to the first embodiment, as shown in FIG. 1, the conductive fiber member 64 is disposed downstream of the static elimination unit 61 in the transfer material transport direction. As shown in FIGS. 1 and 4, the conductive fiber member 64 is provided on a back surface side (downstream side in the transfer material transport direction) of a charge removing member cover 65 to which a charge removing needle 61 as a charge removing means is attached. It is attached in a state where it is fixed by means such as bonding (not shown). Further, the conductive fiber member 64 is not electrically grounded and is in an electrically floating state. The conductive fiber member 64 has a volume resistance of 10 ⁴ The density is set to Ω · cm or less. For example, Denkitol (trade name) manufactured by Japan Vilene Co., Ltd., whose material is carbon fiber, is used. Further, the conductive fiber member 64 having a thickness of 0.5 mm or less is not preferable as a charge removing function, and a thickness of 1.0 mm or more is suitably used. In FIGS. 1 and 4, reference numerals 68 and 69 denote guide members disposed on the upstream side and the downstream side of the static elimination needle 61 as the static elimination means, respectively.
[0042]
Further, the conductive fiber member 64 is disposed such that only the tip end portion 64a contacts the non-image forming surface of the transfer material P. For this reason, the conductive fiber member 64 is attached with its tip end 64a separated from the static elimination member cover 65 at a predetermined angle, and the tip end 64a of the conductive fiber member 64 is attached to the transfer material. The non-image forming surface of P is disposed so as to protrude by a predetermined amount from the transport surface on which it is transported. As a result, only the leading end 64a of the conductive fiber member 64 contacts the non-image forming surface of the transfer material P, and the electric charges accumulated on the non-image forming surface of the transfer material P are transferred to the conductive fiber member 64 itself. The charge is removed by an amount that allows self-discharge while maintaining the voltage. The amount of charge removed by the conductive fiber member 64 is such that, even when the transfer material P is conveyed to the downstream side while being charged to some extent, the transfer material P may be jammed or the transfer material P may be smoothly transferred. This is set to such an extent that it is possible to prevent the image quality from deteriorating due to undesired conveyance or disturbance of the unfixed toner image.
[0043]
Further, as shown in FIG. 5, the conductive fiber member 64 is configured to come into contact with the non-image forming surface of the transfer material P with a certain contact width W from the tip end portion 64a. This is to ensure that the conductive fiber member 64 comes into contact with the non-image forming surface of the transfer material P with a certain contact pressure and nip width, and that static electricity can be reliably removed from the non-image forming surface of the transfer material P. is there. The contact width W of the conductive fiber member 64 is appropriately set according to the amount of protrusion of the distal end portion 64a of the conductive fiber member 64, the inclination angle, and the like.
[0044]
Further, in this embodiment, a plurality of cuts 66 are formed at a predetermined depth at the tip end portion 64a of the conductive fiber member 64, and are divided into a plurality of cuts along a direction orthogonal to the transfer material P transport direction. ing. The leading end portion 64a of the conductive fiber member 64 may be integrally and linearly formed along a direction perpendicular to the transfer direction of the transfer material P as shown in FIG. By dividing into a plurality of parts along the orthogonal direction, accumulation of toner can be prevented.
[0045]
That is, the non-image forming surface of the transfer material P comes into contact with the transfer roll 60 when the toner image is transferred from the secondary intermediate transfer drum 53 by the transfer roll 60, and thus adheres to the surface of the transfer roll 60. The toner may transfer and the toner may adhere. As described above, when the toner adheres to the non-image forming surface of the transfer material P, the leading end portion 64a of the conductive fiber member 64 contacts the non-image forming surface of the transfer material P. The toner adhering to the non-image forming surface of the transfer material P may be scraped by the tip end portion 64a of the conductive fiber member 64, and toner streaks may occur on the non-image forming surface of the transfer material P.
[0046]
Therefore, by dividing the leading end 64a of the conductive fiber member 64 into a plurality of parts along a direction orthogonal to the transfer material transport direction, the toner scraped by the leading end 64a of the conductive fiber member 64 is dispersed. The generation of toner streaks on the non-image forming surface of the transfer material P can be avoided.
[0047]
Further, in this embodiment, as shown in FIG. 6, the tip end portion 64a of the conductive fiber member 64 has a wave shape at a constant period (for example, 5 mm) along a direction orthogonal to the transfer material conveying direction. Are formed continuously. As described above, by continuously forming the irregularities 67 on the tip end portion 64a of the conductive fiber member 64 along the direction orthogonal to the transfer material transport direction, the toner adhered to the non-image forming surface of the transfer material P can be removed. The generation of toner streaks on the non-image forming surface of the transfer material P, which is scraped by the leading end portion 64a of the conductive fiber member 64, can be more effectively prevented.
[0048]
In the above configuration, in the case of a tandem type full-color printer as the image forming apparatus according to the first embodiment, the toner image can be formed without complicating the design and manufacturing process of the image forming apparatus as follows. The transfer material to which the image has been transferred can be appropriately neutralized to prevent jams, hindering smooth transfer of the transfer material, and disturbing the unfixed toner image, thereby deteriorating the image quality. It is possible to prevent it.
[0049]
That is, in the tandem-type full-color printer according to the first embodiment, as shown in FIGS. 2 and 3, when printing a color image or the like, it corresponds to each of the photosensitive drums 11, 12, 13, and 14. The toner images of yellow (Y), magenta (M), black (K), and cyan (C) are formed, and the yellow of each color formed on each of the photosensitive drums 11, 12, 13, and 14 is formed. (Y), magenta (M), black (K), and cyan (C) toner images via a first primary intermediate transfer drum 51 and a second primary intermediate transfer drum 52 to a secondary intermediate transfer drum 53 The toner images of yellow (Y), magenta (M), black (K), and cyan (C) transferred on the secondary intermediate transfer drum 53 in a state of being superimposed on each other are transferred. To collectively transferred onto the transfer sheet P as a transfer material by Lumpur 60.
[0050]
At this time, the toner image of yellow (Y), magenta (M), black (K), and cyan (C) is collectively transferred to the transfer paper P as the transfer material if it is full color. The rear surface of the transfer paper P is charged by the transfer roll 60 to a voltage having a high positive polarity, which is opposite to the charge polarity of the toner. Thereafter, the non-image forming surface side of the transfer sheet P is discharged by receiving a negative discharge by the charge removing means 61, but the non-image forming surface side of the transfer sheet P is charged to a high positive voltage. Therefore, there is a case where the static elimination is not sufficiently performed only by the static elimination receiving the negative discharge by the static elimination means 61.
[0051]
In the first embodiment, as shown in FIG. 1, a conductive fiber member 64 is disposed downstream of the charge removing means 61 in the transfer material transport direction so as to face and contact the non-image forming surface of the transfer material P. Is established. Therefore, when the non-image forming surface of the transfer material P comes into contact with the conductive fiber member 64, the charge of the non-image forming surface of the transfer material P is eliminated by the conductive fiber member 64.
[0052]
At this time, the amount of electric charge removed by the conductive fiber member 64 depends on the volume and the volume resistance of the conductive fiber member 64 and the conductive fiber because the conductive fiber member 64 is not electrically grounded. It is determined by the self-discharge characteristics of the member 64 and the like. The amount of charge removed by the conductive fiber member 64 is such that even if the transfer material P is conveyed to the downstream side in a state of being charged to some extent, a jam occurs in the transfer material P or the transfer material P The setting is made to such an extent that the smooth conveyance is prevented or the unfixed toner image is disturbed so that the image quality is prevented from deteriorating.
[0053]
Therefore, in the tandem-type full-color printer according to the first embodiment, the toner image is transferred without complicating the design and manufacturing process of the image forming apparatus by the simple configuration in which the conductive fiber member 64 is provided. It is possible to remove static electricity from the transferred transfer material appropriately, and to prevent the occurrence of jams, the hindrance of smooth conveyance of the transfer material P, and the occurrence of disturbance in the unfixed toner image, thereby deteriorating the image quality. It is possible to do.
[0054]
Embodiment 2
FIG. 7 shows a second embodiment of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals. In the second embodiment, toner images of different colors are used. A plurality of latent image carriers formed on the surface, a transfer material conveying member for conveying the transfer material, and the toner images formed on the surfaces of the plurality of latent image carriers are conveyed by the transfer material conveying member An image forming apparatus comprising: a plurality of transfer means for performing multiple transfer on a transfer material; wherein the transfer material transport member is provided inside the transfer material transport member and downstream of the transfer means in the transfer material transport direction. The conductive fiber member is arranged so as to face and contact the inner surface of the conductive fiber member.
[0055]
That is, the image forming apparatus according to the second embodiment forms, for example, toner images of each color of yellow (Y), magenta (M), black (K), and cyan (C) as shown in FIG. The photoconductor drums 11, 12, 13, and 14 are horizontally arranged at regular intervals, and an image forming member is disposed around each of the photoconductor drums 11, 12, 13, and 14. Below the photosensitive drums 11, 12, 13, and 14, a transfer material transport belt 100 as a transfer material transport member that transports the transfer material P while holding the transfer material P on its surface is movably disposed. . The transfer unit 101 transfers the toner images of each color such as yellow (Y), magenta (M), black (K), and cyan (C) formed on the surface of each of the photosensitive drums 11, 12, 13, and 14. Is transferred onto the transfer material P conveyed by the transfer material conveyance belt 100 to form a color image.
[0056]
By the way, in the second embodiment, as shown in FIG. 7, on the inner side of the transfer material transport belt 100 2, on the downstream side in the transfer material transport direction of each of the transfer units 101, and on the inner surface of the transfer material transport belt 100 2 The conductive fiber member 64 is arranged so as to face and contact. In the second embodiment, the charge eliminating means is not provided downstream of each transfer means 101, and the conductive fiber member 64 functions as the charge eliminating means.
[0057]
As described above, the conductive fiber member 64 used in the present invention is not limited to neutralizing the transfer material P, and may be used when neutralizing the inner surface side of the transfer material conveying member or the like.
[0058]
【The invention's effect】
As described above, according to the present invention, the transfer material on which the toner image has been transferred can be appropriately neutralized without complicating the design and manufacturing steps of the image forming apparatus, and the occurrence of a jam or the like can be prevented. Further, it is possible to provide an image forming apparatus capable of preventing the smooth conveyance of the transfer medium from being hindered or the unfixed toner image from being disturbed, thereby preventing the image quality from deteriorating.
[Brief description of the drawings]
FIG. 1 is a configuration diagram illustrating a main part of a tandem-type printer as an image forming apparatus according to a first embodiment of the present invention;
FIG. 2 is a schematic configuration diagram showing a tandem-type digital color printer as an image forming apparatus according to Embodiment 1 of the present invention.
FIG. 3 is a configuration diagram illustrating an image forming unit of a tandem-type digital color printer as an image forming apparatus according to Embodiment 1 of the present invention;
FIG. 4 is a perspective view showing an attached state of a conductive fiber member.
FIGS. 5A and 5B are configuration diagrams respectively showing main parts of a tandem-type printer as an image forming apparatus according to Embodiment 1 of the present invention.
FIG. 6 is a front view showing the shape of a conductive fiber member.
FIG. 7 is a configuration diagram illustrating a tandem-type printer as an image forming apparatus according to Embodiment 2 of the present invention;
[Explanation of symbols]
1: Printer main body, 60: Transfer roll (transfer means), 62: Static elimination needle (static elimination means), 64: Conductive fiber member, 64a: Tip of conductive fiber member.

Claims (7)

At least one latent image carrier on which a toner image is formed, and transfer for transferring the toner image formed on the surface of the latent image carrier via at least one intermediate transfer member or directly onto a transfer material Means, and an image forming apparatus provided on the downstream side of the transfer unit in the transfer material transport direction, and a charge removing unit configured to remove charges accumulated on the transfer material.
An image forming apparatus, wherein a conductive fiber member is disposed downstream of the charge removing unit in the transfer material transport direction so as to face and contact a non-image forming surface of the transfer medium. The image forming apparatus according to claim 1, wherein only a leading end of the conductive fiber member contacts a non-image forming surface of the transfer material. The image forming apparatus according to claim 1, wherein the conductive fiber member contacts a non-image forming surface of the transfer material with a certain contact width from a leading end thereof. 2. The image forming apparatus according to claim 1, wherein the conductive fiber member has a tip portion divided into a plurality of portions along a direction orthogonal to a transfer material conveying direction. The image forming apparatus according to claim 1, wherein the conductive fiber member is formed with irregularities continuously at a front end thereof in a direction orthogonal to a transfer material conveying direction. The image forming apparatus according to claim 1, wherein the conductive fiber member is not electrically grounded. A plurality of latent image carriers each having a different color toner image formed on the surface thereof, a transfer material conveying member for conveying a transfer material, and the toner images formed on the surface of the plurality of latent image carriers are transferred. An image forming apparatus comprising: a plurality of transfer units that multiplexly transfer onto a transfer material conveyed by a material conveying member;
A conductive fiber member is disposed inside the transfer material transport member and downstream of the transfer means in the transfer material transport direction so as to face and contact the inner surface of the transfer material transport member. Image forming apparatus.

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