JP2004070084A - Cleaning device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To keep residual toner clear-away performance satisfactory all the time without being affected by a state of residual toner (an amount of residual toner or the type of residual toner) in an aspect equipped with a cleaning roll. <P>SOLUTION: A cleaning device 4 which clears away toner T remaining on a beltlike member 1 includes the cleaning roll 5 to which the residual toner T is electrostatically attracted, a layer thickness adjustment member 6, disposed upstream of the cleaning roll 5, for extending and adjusting the layer of residual toner T to a reference thickness or below, and an electrostatic charge control member 7, disposed upstream of the cleaning roll 5, for controlling the electrostatic charge polarization and the amount of electrostatic charges of the toner T remaining on the beltlike member 1. The image forming apparatus includes the cleaning device 4. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a cleaning device used in an image forming apparatus such as a copying machine, a laser printer, and a facsimile, and more particularly, to a cleaning device that cleans toner remaining on a belt-shaped member and an improvement in an image forming apparatus using the same. .
[0002]
[Prior art]
2. Description of the Related Art In recent years, as an image forming apparatus such as a color printer or a color copying machine using an electrophotographic method, an image forming apparatus employing an intermediate transfer method is increasing.
A color image forming apparatus employing such an intermediate transfer system, for example, around the photosensitive drum, charging, exposing, developing and cleaning each electrophotographic device, while, for example, relative to the primary transfer position of the photosensitive drum Intermediate transfer belts are arranged to face each other, and a toner image of each color component (for example, yellow (Y), magenta (M), cyan (C), black (K)) is formed on the photosensitive drum. After the primary transfer is sequentially performed on the intermediate transfer belt by the electrostatic action of the primary transfer device at the transfer position, the composite primary transfer image superimposed on the intermediate transfer belt is transferred to the electrostatic transfer of the secondary transfer device at the secondary transfer position. Transfer to a recording material such as paper or an OHP sheet by a mechanical action to form a desired color image on the recording material (see, for example, JP-A-5-323704). .
[0003]
When a toner image is transferred from an intermediate transfer belt to a recording material, not all of the toner on the intermediate transfer belt is transferred to the recording material, and a part of the toner remains on the intermediate transfer belt. Therefore, a cleaning device (belt cleaner) for removing the toner remaining on the intermediate transfer belt is provided downstream of the secondary transfer position in the traveling direction of the intermediate transfer belt. As this cleaning device, a device in which a cleaning member is brought into contact with or separated from the intermediate transfer belt in accordance with a cleaning timing in order to scrape off residual toner on the intermediate transfer belt is used.
Here, as a cleaning member, an elastic blade, a fur brush, a conductive roll, or the like is known.
[0004]
In this type of cleaning device, for example, in a mode in which an elastic blade is used as a cleaning member, when the elastic blade separates, toner deposited on the tip of the elastic blade remains on the intermediate transfer belt, and an image is formed on the intermediate transfer belt in the next process. However, there is a problem that blade marks are generated. Further, there is a problem that the elastic blade and the intermediate transfer belt are worn by long-term use, resulting in poor cleaning and a decrease in transfer efficiency.
Further, in a mode in which a fur brush (brush roll) is used as a cleaning member, there is a problem that the apparatus becomes large and complicated, and the cost increases.
Therefore, from the viewpoint of solving these problems, a system using a conductive roll (cleaning roll) as a cleaning member may be adopted.
[0005]
A cleaning method using a cleaning roll of this type includes a method in which residual toner on the intermediate transfer belt is electrostatically adsorbed to the cleaning roll and collected (for example, Japanese Patent Application Laid-Open Nos. No. 7226) and a method in which the polarity of the residual toner on the intermediate transfer belt is made uniform by a charge control roll, and then collected by a collecting cleaning roll (including a photosensitive drum) (for example, JP-A-1-105980). JP-A-4-81785, JP-A-9-44007, JP-A-2000-34131, JP-A-2000-42655, and JP-A-2000-284606.
[0006]
[Problems to be solved by the invention]
However, among the cleaning devices using a cleaning roll, in the former method, a bias voltage having a polarity opposite to that of the toner (a DC voltage or an AC voltage is superimposed on a DC voltage) is applied, and the toner is attracted to the cleaning roll. Then, the residual toner adsorbed by the cleaning roll blade or brush is scraped off and collected.
At this time, the toner that can be electrostatically attracted is a toner of the same polarity, but the charge distribution of the secondary transfer residual toner is not necessarily uniform, and the toner that cannot be collected is mixed because toners of different polarities are mixed. Remains on the intermediate transfer belt, and is mixed during the next image formation.
For this reason, the latter method may be employed in order to sufficiently collect the secondary transfer residual toner.
[0007]
Certainly, in the latter method (a method in which the toner is collected after the polarity is adjusted), the charge distribution of the secondary transfer residual toner is adjusted in advance by the charge control roll, and then the toner is adsorbed to the cleaning roll. The technical problem of remaining toner is small.
However, when a large amount of the secondary transfer residual toner remains on the intermediate transfer belt as in the case of a color image, even if the charge distribution of the secondary transfer residual toner is previously adjusted by the charge control roll, it is difficult to form the toner layer having an overlapping layer. For this reason, it is difficult to make the polarity even to the lower toner layer.
[0008]
Further, in the case of toner that has not been secondary-transferred due to paper conveyance failure, it is difficult to collect and align the polarity because the toner is further overlaid. There is a technical problem of being connected.
Further, in the case of the two-component developing method which is sometimes used in an image forming apparatus such as a color printer and a color copying machine, the toner is charged by frictional charging with the carrier as compared with the one-component developing method. Even if the charge distribution of the secondary transfer residual toner is made uniform by the control roll, the charge distribution may be wide, and it is difficult to make the charge distribution uniform enough. There is a technical problem that the cleaning becomes difficult and sufficient cleaning is not performed.
[0009]
As another conventional cleaning method, for example, a toner collection roll is disposed prior to a brush roll as a cleaning member, and the toner is physically collected by the toner collection roll to leave a fixed amount of toner ( A two-stage toner collection method has been proposed (for example, see Japanese Patent Application Laid-Open No. 4-69682).
However, in this mode, since it is necessary to collect toner at two locations, not only must a wide space for collecting toner be secured at two locations, but also a common transport system for the collected toner. In that case, it is not preferable in that the layout is restricted.
[0010]
Further, as another conventional cleaning method, a brush that rubs against the intermediate transfer member is provided, and a voltage having the same polarity as that of the toner on the intermediate transfer member is applied to the brush. Is moved, and then a voltage having the same polarity as the toner is applied to the intermediate transfer member, thereby returning the toner moved at the nip portion between the intermediate transfer member and the photoconductor to the photoconductor side, or cleaning with a blade. A method is also known (for example, see Japanese Patent Application Laid-Open No. 8-262879).
However, in this type of cleaning method, even when the toner is moved by a brush to which a voltage having the same polarity is applied, the electrostatic adhesion of the toner to the intermediate transfer body is not reduced, so that the photosensitive Even if the toner is returned to the body or blade cleaning is performed, it is difficult to sufficiently remove the residual toner if the residual toner is large. In particular, when a material having a high coefficient of friction, such as an elastic body, is used for the intermediate transfer member, this is not preferable in that the rotational load on the intermediate transfer member by the brush increases.
[0011]
The present invention has been made to solve the above technical problem, and in an embodiment including a cleaning roll, without being affected by the state of residual toner (amount of residual toner or type of residual toner), Provided is a cleaning device capable of always maintaining good cleaning performance of residual toner, and an image forming apparatus using the same.
[0012]
[Means for Solving the Problems]
That is, as shown in FIG. 1, the present invention relates to a cleaning device 4 for cleaning the toner T remaining on the belt-shaped member 1, and a cleaning roll 5 for electrostatically attracting the residual toner T; A layer thickness adjusting member 6 provided on the upstream side of the roll 5 to stretch and adjust the residual toner T layer to a reference thickness or less, and a toner thickness adjusting member 6 provided on the upstream side of the cleaning roll 5 and remaining on the belt-shaped member 1. And a charge control member 7 for controlling the charge polarity and charge amount.
[0013]
In such technical means, the belt-shaped member 1 widely includes a belt-shaped photoconductor, a belt-shaped intermediate transfer body, and the like.
In addition, since the present invention is directed to a device provided with the cleaning roll 5, a device using a blade or a brush alone as a cleaning member is excluded.
Here, the cleaning roll 5 may be an independent functional member, or may be used also as another functional member (for example, a photosensitive drum).
Incidentally, a cleaning bias VBC is normally applied to the cleaning roll 5 so that the residual toner T on the belt-shaped member 1 is electrostatically attracted.
[0014]
Further, the layer thickness adjusting member 6 may be in any form such as a blade shape or a roll shape as long as it can stretch and adjust the residual toner T layer, and is usually arranged in contact with the belt-shaped member 1 with a predetermined pressing force. However, even when the electric field curtain is not in contact with the belt-shaped member 1, the residual toner T layer may come into contact with the residual toner T layer when the thickness exceeds the reference thickness, or the back surface of the belt-shaped member 1 may be constantly contacted. It also includes a mode of adjusting the layer thickness by the action.
Further, as shown in FIG. 1, the layer thickness adjusting member 6 only needs to adjust the thickness d0 of the residual toner T layer to a predetermined thickness d1 equal to or less than the reference thickness.
Here, the “reference thickness” is appropriately selected according to the type (particle size, charge amount, etc.) of the toner and the charging ability of the charge control member 7. 7 means a thickness that can guarantee that the charging polarity and the charging amount are controlled to a desired state.
[0015]
Further, in the embodiment in which the layer thickness adjusting member 6 is arranged in contact with the belt-shaped member 1, when the layer thickness adjusting member 6 is strongly pressed against the belt-shaped member 1, the load received from the layer thickness adjusting member 6. As a result, the residual toner T is strongly pressed against the belt-shaped member 1 and the mechanical attraction between the residual toner T and the belt-shaped member 1 is increased.
On the other hand, when the layer thickness adjusting member 6 is very weakly pressed against the belt-shaped member 1, the force for moving the residual toner T due to the load received from the layer thickness adjusting member 6 does not work, and the residual toner T layer is uniformly formed. It is difficult to stretch and cannot be thinned. In addition, even when a thin layer is formed, partial spots are easily formed.
Therefore, the pressing force of the layer thickness adjusting member 6 on the belt-shaped member 1 needs to be set to an appropriate load depending on the materials of the belt-shaped member 1 and the layer thickness adjusting member 6.
[0016]
The charge control member 7 may be appropriately selected as long as it controls the charge polarity and the charge amount of the residual toner T. The charge control member 7 is usually separate from the layer thickness adjusting member 6, but it is possible to realize both functions. For example, they may be integrally configured.
The form of the charge control member 7 may be appropriately selected, such as a roll shape, and a charging bias VBT is normally applied to the charge control member 7.
[0017]
Further, in a mode in which the layer thickness adjusting member 6 and the charge control member 7 are provided separately, it is preferable that the layer thickness adjusting member 6 is arranged on the upstream side of the charge control member 7.
According to this aspect, the charge control is performed after the thickness of the residual toner T layer is reduced, and the charged state of the residual toner T layer can be made uniform.
[0018]
Further, from the viewpoint of softly thinning the residual toner T layer, it is preferable to apply the thin layer bias VBH to the layer thickness adjusting member 6.
Here, the bias VBH for the thin layer is not limited to a DC component or an AC component as long as it has a function of weakening the adsorption force of the residual toner T to the belt-shaped member 1.
Therefore, the form of the thin layer bias VBH includes “only a DC component”, “only an AC component”, or “DC component + AC component”.
[0019]
For example, when the thin layer bias VBH has at least a DC component, the DC component is a polarity that acts as a force acting in a direction in which the residual toner T moves from the belt-shaped member 1 to the layer thickness adjusting member 6 side. Preferably, in this case, it is considered that this direct current component acts to peel off the residual toner T from the belt-shaped member 1.
On the other hand, when the thin layer bias VBH has at least an AC component, the AC component acts to reduce the adhesion of the residual toner T layer to the belt-shaped member 1 due to the vibration caused by the alternating electric field. it is conceivable that.
[0020]
Further, as an effective mode for securing the effect of stretching the residual toner T layer, the layer thickness adjusting member 6 may provide a frictional resistance between the belt-like member 1 and the extent that the residual toner T layer is stretched. preferable.
In this case, examples of the layer thickness adjusting member 6 include a mode in which the layer thickness adjusting member 6 does not rotate with respect to the belt-shaped member 1 and a mode in which the surface thereof is roughened.
[0021]
Further, as a preferred embodiment of the layer thickness adjusting member 6, a member provided with a conductive member 6a and an insulating member 6b, wherein the insulating member 6b is arranged to face the residual toner T layer on the belt-shaped member 1 is exemplified. Can be
As a preferable use mode of this kind of the layer thickness adjusting member 6, a thin layer bias VBH may be applied to the conductive member 6a of the layer thickness adjusting member 6.
In this way, the electric field attracting force acts, so that the upper portion of the residual toner T layer can be attracted to the insulating member 6b, and the effect of extending the residual toner T layer can be ensured accordingly.
[0022]
As a typical mode of the layer thickness adjusting member 6 having the “conductive member 6a + insulating member 6b” structure, for example, if the configuration is simplified, a member in which the conductive member 6a and the insulating member 6b are integrated. And at least the surface side of the conductive member 6a is covered with an insulating member 6b.
On the other hand, in consideration of prolonging the life of components, there is an embodiment in which the conductive member 6a and the insulating member 6b are configured to be separable and the insulating member 6b is replaceable.
[0023]
Further, the present invention is not limited to the cleaning device 4 but also applies to an image forming apparatus using the same.
In this case, as shown in FIG. 1, the present invention provides a belt-shaped member 1 carrying a toner image TZ, a transfer device 3 for transferring the toner image TZ on the belt-shaped member 1 to a transfer medium 2, and a belt. In an image forming apparatus provided with a cleaning device 4 for cleaning the toner T remaining on the shaped member 1, the above-described cleaning device is used as the cleaning device 4.
A typical example of this type of image forming apparatus uses an intermediate transfer type image forming apparatus in which the belt-like member 1 is used as an intermediate transfer member.
[0024]
Next, the operation of the above-described cleaning device 4 will be described.
For example, after transferring the toner image TZ formed on the belt-shaped member 1 to the transfer medium 2, untransferred toner T remains on the belt-shaped member 1, and the residual toner T is cleaned by the cleaning device 4. You.
In general, when cleaning the residual toner T, only by contacting the cleaning roller 5 to which the cleaning bias VBC is applied with the belt-shaped member 1, the charge distribution of the residual toner T is wide, and if the environment is different, the charge distribution is large. Therefore, electric attraction (movement of toner) from the belt-shaped member 1 to the cleaning roll 5 is unstable and is not sufficiently performed.
[0025]
For this reason, in order to stably perform the electric suction (movement of the toner) by the cleaning roll 5, the charging bias VBT is applied by separately using the charging control member 7 to make the polarity of the residual toner T uniform, and the suction is performed. The charge polarity and charge amount of the previous residual toner T are controlled.
At this time, in the case of a single color, for example, as shown in FIG. 3A, the amount of toner remaining on the belt-shaped member 1 after transfer is small, and most of the residual toner T is electrostatically removed by the charging control member 7. It is possible to make the charge capable of being adsorbed.
[0026]
However, when the toner amount of a single color is 100%, the toner amount becomes 200% as in a two-color superimposed image, or in particular, the toner amount becomes 300% as in a three-color superimposed image. For example, when the residual toner T is a thick layer, as shown in FIG. 3B, the amount of toner remaining on the belt-like member 1 after transfer also increases, and the charge control member 7 reduces the amount of charge of the residual toner T. Even if it is attempted to control, it is difficult to make the residual toner T in the lower layer electrostatically attractable.
In this case, there is a concern that the residual toner T of the lower layer among the residual toners T on the belt-shaped member 1 is not collected on the cleaning roll 5 side and remains on the belt-shaped member 1 side.
[0027]
Therefore, for example, a layer thickness adjusting member 6 is provided in front of the charge control member 7, and the toner amount (reference thickness d) of this layer thickness adjusting member 6 is such that the charge can be charged electrostatically by the charge control member 7. By adjusting the residual toner T layer to the following toner amount, for example, as shown in FIG. Even when the toner amount becomes 300% as in the case of the image shown in FIG. 2, as shown in FIG. 2A, for example, the overlapping state of the residual toner T is substantially the same as the toner amount of the single color.
For this reason, the residual toner T that has passed through the layer thickness adjusting member 6 can be charged by the charging control member 7 so that most of the residual toner T can be electrostatically attracted. Adsorption (movement of toner) can be performed.
[0028]
At this time, it is preferable to apply a thin layer bias VBH to the layer thickness adjusting member 6 in the layer thickness adjusting process by the layer thickness adjusting member 6.
For example, reducing the amount of charge of the residual toner T is preferable in that the attraction force between the belt-shaped member 1 and the residual toner T is reduced, and the residual toner T layer is easily thinned. It is effective to apply a bias including an AC component as the layer bias VBH.
When a thin layer bias VBH (for example, an AC bias with a DC bias superimposed thereon) containing a DC component in a direction in which the residual toner T is adsorbed is applied to the layer thickness adjusting member 6, the residual toner T is attracted to the layer thickness adjusting member 6. As a result, the attraction force between the belt-shaped member 1 and the residual toner T further decreases, and the residual toner T moves more easily.
[0029]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.
◎ Embodiment 1
FIG. 4 is a schematic configuration diagram showing Embodiment 1 of the image forming apparatus to which the present invention is applied.
In FIG. 1, the image forming apparatus includes a photoconductor drum 10 and an intermediate transfer belt 20 that is arranged in contact with the photoconductor drum 10 to transfer a toner image from the photoconductor drum 10 in an apparatus main body 15. Have.
In the present embodiment, the photosensitive drum 10 has a photosensitive layer whose resistance value is reduced by light irradiation, and a charging device 11 for charging the photosensitive drum 10 is provided around the photosensitive drum 10. An exposure device 12 that writes an electrostatic latent image of each color component (yellow, magenta, cyan, and black in this example) on the charged photoconductor drum 10, and each color component latent image formed on the photoconductor drum 10 A rotary developing device 13 for visualizing the toner image with each color component toner, the intermediate transfer belt 20, and a cleaning device 14 for cleaning residual toner on the photosensitive drum 10 are provided.
[0030]
Here, for example, a charging roll is used as the charging device 11, but a charging device such as a corotron may be used.
The exposure device 12 may be any device that can write an image on the photosensitive drum 10 by light. In this example, for example, a print head using an LED is used. However, the present invention is not limited to this. For the print head, a scanner that scans the laser beam with a polygon mirror may be appropriately selected.
Further, the rotary developing device 13 rotatably mounts the developing devices 13a to 13d accommodating the respective color component toners. For example, the respective color component toners adhere to portions of the photoreceptor drum 10 whose potential has been reduced by exposure. The toner to be used is not particularly limited as long as the toner is used, and the shape and the particle diameter of the toner are not particularly limited. In this example, the rotary developing device 13 is used, but four developing devices may be used in an arrangement in which the developing devices are arranged in order.
Further, the cleaning device 14 may be appropriately selected as long as it cleans the residual toner on the photosensitive drum 10, such as a device using a blade cleaning system.
However, when toner having a high transfer rate is used, there may be a mode in which the cleaning device 14 is not used. At this time, in a case where the system is such that the residual toner on the intermediate transfer belt 20 is collected by the photosensitive drum 10, a mechanism (for example, a developer is used to collect the residual toner on the photosensitive drum 10 collected by the photosensitive drum 10). And a recoverable developing device).
[0031]
Further, as shown in FIG. 4, the intermediate transfer belt 20 is wound around three tension rolls 21 to 23, and is located between the rotary developing device 13 and the cleaning device 14. 10 and are disposed opposite to each other.
Here, the intermediate transfer belt 20 and the photosensitive drum 10 are driven by different drive systems, respectively, and for example, of the stretching rolls 21 to 23, for example, the stretching roll 21 functions as a driving roll. .
A primary transfer roll 25 as a primary transfer device is arranged in contact with a portion where the intermediate transfer belt 20 nips the photosensitive drum 10 from the back side of the intermediate transfer belt 20, and a predetermined primary transfer bias is applied. .
Further, a secondary transfer roll 26 as a secondary transfer device is disposed opposite to the tension roll 22 of the intermediate transfer belt 20 using the tension roll 22 as a backup roll. , A predetermined secondary transfer bias is applied, and a stretching roll 22 also serving as a backup roll is grounded.
Further, a cleaning device (belt cleaner) 30 is disposed downstream of the secondary transfer portion of the intermediate transfer belt 20 and upstream of the primary transfer portion.
A recording material 40 such as paper is stored in a supply tray 41, is supplied by a pickup roll 42, is guided to a secondary transfer portion via a registration roll 43, and is transferred to a fixing device 50 through a transport belt 44. The sheet is conveyed and further conveyed to a discharge tray 48 via a transfer roll 45 and a discharge roll 46.
[0032]
In the present embodiment, the intermediate transfer belt 20 is made of a synthetic resin such as polyimide, polycarbonate, polyester, or polypropylene or various rubbers containing an appropriate amount of an antistatic agent such as carbon black. Resistivity is 10 ⁶ -10 ¹⁴ Ω · cm is used.
Here, as the intermediate transfer belt 20 having elasticity (hereinafter referred to as an elastic intermediate transfer belt if necessary), silicone rubber, NBR, H-NBR, CR, EPDM, urethane rubber may be used as the main base material of the conductive elastic layer. And the like. The material of the conductive protective layer is not particularly limited as long as it can achieve the objectives of reducing frictional resistance, stabilizing the electric characteristics to the environment, and improving the residual toner cleaning property by reducing the surface roughness. Has been developed by using a fluororesin polymer such as polytetrafluoroethylene (PTFE), a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether (PFA), or PVdF, with an alcohol-soluble nylon, silicone resin, silane coupler, or urethane resin. Use paints that are dissolved and dispersed in emulsions and organic solvents It can be. These protective layers can be provided by applying the above coating material by dip coating, spray coating, electrostatic coating, roll coating, or the like. Further, by subjecting the protective layer to a surface treatment or polishing, the releasability, conductivity, abrasion resistance, and surface cleaning property can be improved.
In this example, for example, the elastic intermediate transfer belt 20 is used.
[0033]
Further, in the present embodiment, the secondary transfer roll 26 and the cleaning device (belt cleaner) 30 are disposed so as to be able to come in contact with and separate from the intermediate transfer belt 20, and when a color image is formed, the final color is formed. Until the unfixed toner image is primarily transferred onto the intermediate transfer belt 20, at least the cleaning device 30 is separated from the intermediate transfer belt 20.
Here, the secondary transfer roll 26 includes a surface layer made of a urethane rubber tube in which carbon is dispersed, and an internal layer made of foamed urethane rubber in which carbon is dispersed. Is coated with fluorine. This secondary transfer roll 26 has a volume resistivity of 10 ³ -10 ¹⁰ It is set to Ω · cm, the roll diameter is set to, for example, φ28 mm, and the hardness is set to, for example, 30 ° (Asuka C).
On the other hand, the backup roll (stretch roll) 22 is provided with a surface layer made of a blended rubber tube of EPDM and NBR in which carbon is dispersed, and an inner layer made of EPDM rubber, and has a surface resistivity of 10%. ⁷ -10 ¹⁰ Ω / □, the roll diameter is set to, for example, φ28 mm, and the hardness is set to, for example, 70 ° (Asuka C).
[0034]
Further, in the present embodiment, as shown in FIGS. 4 and 5, the cleaning device 30 comes into contact with the intermediate transfer belt 20 at a position facing the tension roll 21 so as to be able to freely contact with and separate from the intermediate transfer belt 20. A cleaning roller 31 electrostatically adsorbing the residual toner, and an intermediate transfer belt which is in contact with the intermediate transfer belt 20 at a position facing the stretching roll 23 located on the upstream side of the cleaning roll 31, A layer thickness adjusting member 32 that adjusts the layer thickness of the residual toner on the intermediate transfer belt 20; And a charge control member 33 for controlling the charge polarity and charge amount of the residual toner on the intermediate transfer belt 20.
[0035]
In this embodiment, a bias power supply 35 for applying a cleaning bias VBC is connected to the cleaning roll 31, as shown in FIG.
Here, as the cleaning roll 31, a conductive support as a roll shaft is made of iron, nickel-plated iron, copper, stainless steel, etc., and as a conductive elastic layer, epichlorohydrin rubber, polyether urethane, polyester is used. Binder used for surface layer by mixing 0.01 to 10% of various alkyl ammonium salts having an alkali metal / quaternary ammonium salt structure with urethane rubber, chloroprene rubber, NBR, EPDM blended NBR rubber, SBR rubber, butyl rubber, etc. Examples of the resin include polyester, polyamide, polyurethane, melamine resin, acrylic resin such as PMMA or PMBA, polyvinyl butyral, polyvinyl acetal, polyarylate, polycarbonate, phenoxy resin, polyurea, and polyvinyl acetate. It can be.
Further, the cleaning roll 31 has a resistance value of 10% by volume resistivity. ⁵ -10 ¹¹ Ω · cm (when 1 kV is applied) is desirable, but not limited to this, and a metal roll can be used as described below.
For example, when the elastic intermediate transfer belt 20 is used, since the intermediate transfer belt 20 is an elastic member, the adhesion between the intermediate transfer belt 20 and the cleaning roll 31 is increased. A member having high hardness, such as a metal roll made of copper or stainless steel, can also be used.
A toner collecting member (not shown) is provided on the cleaning roll 31 so as to scrape and remove residual toner adsorbed on the cleaning roll 31. Further, without using the cleaning roll 31, the residual toner on the intermediate transfer belt 20 is electrostatically adsorbed to the photosensitive drum 10 (substantially functions as a cleaning roll) at the primary transfer section, and It is also possible to collect by the cleaning device 14.
[0036]
Further, in the present embodiment, a layer thickness adjusting blade is used as the layer thickness adjusting member 32, and a bias power supply 36 for applying a thin layer bias VBH is connected to the layer thickness adjusting blade 32.
Here, as the layer thickness adjusting blade 32, as long as it is blade-shaped, only the conductive member, only the insulating member, or both may be appropriately manufactured using them. In the present embodiment, for example, As shown in FIG. 6A, a conductive plate material 51 in which one end side is coated with an insulating coating material 52 is used.
Here, for example, a SUS plate is used as the conductive plate material 51, and urethane rubber is used as the insulating coating material 52. As a specific example, a 0.2 mm thick and 20 mm wide (15 mm free length) is used. A SUS plate coated with urethane rubber having a thickness of 0.5 mm to a position 10 mm from the tip is cited.
[0037]
As a method for pressing the layer thickness adjusting blade 32, a doctor method or a wiper method is possible. For example, a wiper method is desirable in order to reduce the load on the elastic intermediate transfer belt 20.
Further, the bite amount of the layer thickness adjusting blade 32, the set angle (the inclination posture angle with respect to the intermediate transfer belt 20), the contact surface roughness, and the like are appropriately set within a range of a load that does not cause a problem in image formation of the intermediate transfer belt 20. What is necessary is just to set it.
As a specific example, there is an embodiment in which the bite amount at the tip of the layer thickness adjusting blade 32 is set to 0.6 mm, the set angle is set to 10 °, and the contact surface roughness is set to 20 Ra with respect to the elastic intermediate transfer belt 20.
[0038]
Further, the bias VBH for the thin layer may be any of a DC component only, an AC component only, or a component containing both components, but from the viewpoint of maintaining a good thin layer effect of the residual toner layer, at least the DC component may be used. A bias including a component, preferably a bias including an AC component in which a DC component is superimposed is preferable.
[0039]
The layer thickness adjusting blade 32 is not limited to the embodiment shown in FIG. 6A, but may be an embodiment shown in FIGS. 6B to 6F.
Here, FIG. 6B shows a conductive plate material 51 in which the distal end and both surfaces on the distal end side are coated with an insulating coating material 52. For example, a SUS plate having a thickness of 0.2 mm and a width of 20 mm (a free length of 15 mm) is formed. , 0.5 mm thick urethane rubber coated to a position 10 mm from the tip.
Further, FIG. 6C shows a state in which the front end of the conductive plate member 51 and both surfaces on the front end side are covered with a semiconductive member 53, and the insulating cover member 54 is coated thereon. A SUS plate having a width of 20 mm (a free length of 15 mm) is kneaded and molded with 1.0 mm thick semiconductive rubber (for example, urethane rubber and carbon, and has a volume resistivity of 10 mm). ⁷ Rubber adjusted to about Ω · cm), and further covered with a 0.2 mm-thick urethane rubber.
According to this aspect, it is preferable in that leakage is unlikely to occur even when the thickness of the insulating covering material 54 is reduced by using the semiconductive member 53 as an intermediate layer.
[0040]
Further, FIG. 6 (d) shows a configuration in which one surface on the tip side of the conductive plate material 51 is covered with an insulating coating material 54 via a semiconductive member 53, and is, for example, 0.2 mm thick and 20 mm wide. An embodiment in which a resin having a two-layer structure of 1.5 mm thick semiconductive rubber and 0.5 mm thick urethane rubber is adhered to a SUS plate (free length: 15 mm).
This embodiment is also preferable, as in the case of FIG.
Further, the conductive plate material 51 of the layer thickness adjusting blade 32 does not need to be present near the front end, and when it is desired to set the pressing force of the layer thickness adjusting blade 32 to be weak, FIG. As shown in f), the position of the leading end of the conductive plate member 51 may be set back from the leading end of the layer thickness adjusting blade 32, and the substantial free length of the layer thickness adjusting blade 32 may be set longer. 6 (e) and 6 (f), the same components as those in FIGS. 6 (a) to 6 (d) are denoted by the same reference numerals, and detailed description thereof will be omitted.
[0041]
In the present embodiment, as shown in FIG. 5, for example, a charge control roll is used as the charge control member 33, and a bias power supply 37 for applying a charging bias VBT is connected to the charge control roll 33. Have been.
Here, the charging control roll 33 may be configured in the same manner as the cleaning roll 31, but may have a volume resistivity lower than that of the cleaning roll 31. ² -10 ⁸ A resistance of Ω · cm (when 1 kV is applied) is desirable. However, the present invention is not limited to this range, and a metal roll can be used as in the case of the cleaning roll 31.
In the present embodiment, the layer thickness adjusting blade 32 and the charging control roll 33 are arranged to face the stretching roll 23 which is different from the stretching roll 21 which faces the cleaning roll 31. Alternatively, they may be opposed to the same tension roll. The same applies to the following embodiments.
[0042]
Next, the operation of the image forming apparatus according to the present embodiment will be described.
In the image forming apparatus according to the present embodiment, each color component toner image is sequentially formed on the photosensitive drum 10 and is sequentially transferred to the intermediate transfer belt 20 at the primary transfer position, and then the recording material 40 is formed at the secondary transfer position. All at once.
In such an image forming process, the toner T remaining on the intermediate transfer belt 20 is collected by a cleaning device (belt cleaner) 30, as shown in FIG.
[0043]
That is, when the residual toner T on the intermediate transfer belt 20 is a thin layer, as shown in FIG. 7A, it passes through the layer thickness adjusting blade 32 as it is and reaches the charge control roll 33. However, since the residual toner T layer is originally a thin layer, the charging control roll 33 reliably controls the charging polarity and the charging amount.
Therefore, the residual toner T that has reached the cleaning roll 31 via the charging control roll 33 is almost completely electrostatically attracted to the cleaning roll 31 and collected by a toner collecting member (not shown).
[0044]
On the other hand, when the residual toner T on the intermediate transfer belt 20 is a thick layer, the residual toner T on the intermediate transfer belt 20 passes through the layer thickness adjusting blade 32 as shown in FIG. The layer thickness is adjusted to be equal to or less than the reference thickness d (in this example, for example, the thickness of the toner layer remaining in the single-color mode).
For this reason, when the residual toner T whose layer thickness has been adjusted reaches the charging control roll 33 located on the downstream side of the layer thickness adjusting blade 32, the residual toner T layer is smaller than the reference thickness d. T is controlled by the charge control roll 33 to a predetermined charge polarity and charge amount.
Therefore, the residual toner T that has reached the cleaning roll 31 via the charging control roll 33 is almost completely electrostatically attracted to the cleaning roll 31 and collected by a toner collecting member (not shown).
[0045]
In particular, in the present embodiment, the layer thickness adjusting blade 32 is provided with an insulating coating material 52 or 54 on the side of the intermediate transfer belt 20 of the conductive plate material 51, for example, as shown in FIGS. Since the thin layer bias VBH including the DC component is applied, the following operation is achieved.
That is, by applying a bias VBH for a thin layer in which a DC component (for example, Vdc: 1.8 kV) is superimposed on the layer thickness adjusting blade 32, the residual toner T can be more easily moved. The electrostatic attraction force with the residual toner T can be reduced, and the residual toner T layer can be extended.
[0046]
Here, as shown in FIG. 8, when a conductive member having high electric conductivity (conductive layer in the figure), for example, a conductor / semiconductor is brought into contact with the toner layer, when a voltage is applied to the conductive member, the toner layer becomes conductive. Injection and discharge of current to reduce the toner charge and invert the polarity (in order to weaken the adsorption force of the toner electrostatically adsorbed on the intermediate transfer belt 20, a voltage having a polarity opposite to the toner charge polarity is applied. Need to be done).
However, the electric field formed due to current injection and discharge is weakened, and the toner layer is stretched mainly by mechanical force, so the toner layer can be stretched, but the pressing load and angle are optimized There is a need.
On the other hand, by making the surface in contact with the toner an insulating member (insulating coating material 52 or 54), even if a voltage is applied to the conductive member (corresponding to the conductive plate material 51), the insulating member is As a result, injection and discharge of current into the toner layer are suppressed, and the toner layer is insulated by a strong electric field by the applied voltage with respect to the toner layer electrostatically adsorbed on the intermediate transfer belt 20. The toner is electrically sucked by the member, so that the toner layer is easily divided, and the toner layer can be easily extended.
[0047]
Further, in the present embodiment, the layer thickness adjusting blade 32 is configured such that the conductive member (conductive plate member 51) and the insulating member (insulating coating member 52 or 54) are integrally formed. The present invention is not limited to this, and as shown in FIGS. 9A and 9B, the conductive member and the insulating member may be configured separately.
Here, the layer thickness adjusting blade 32 shown in FIG. 9A provides the semi-conductive member 53 on one surface on the tip side of the conductive plate member 51, while holding the insulating film 56 as an insulating member in the holder 55. The semiconductive member 53 presses the insulating film 56 against the intermediate transfer belt 20.
[0048]
The layer thickness adjusting blade 32 shown in FIG. 9B is substantially the same as that shown in FIG. 9A, but is further provided with a locking piece 56 a at the end of the insulating film 56 to lock the holder 55. The engaging piece 56a of the insulating film 56 is engaged with the receiving portion 55a in a detachable manner.
In particular, in the embodiment shown in FIG. 9B, the insulating member (here, the insulating film 56) in contact with the intermediate transfer belt 20 is configured as a replaceable part, so that the insulating member is worn. Even if the performance deteriorates due to the above-mentioned factors and the image forming apparatus cannot be used earlier than the image forming apparatus or the submodule, the performance of the layer thickness adjusting blade 32 can be maintained by replacing the insulating member.
9A and 9B, the thin plate bias VBH is normally applied to the conductive plate 51. This is the same in each embodiment shown in FIG.
[0049]
Further, in the present embodiment, the layer thickness adjusting blade 32 is formed by continuously bonding the insulating covering material 52 to the conductive plate material 51 as shown in FIG. However, the present invention is not limited to this. For example, as shown in FIG. 10A-2, a plurality of insulating coating materials 52 may be bonded to a conductive plate material 51 at predetermined intervals. As a specific example, for example, a SUS plate having a thickness of 0.1 mm and a width of 20 mm (free length of 10 mm) is formed by bonding a plurality of urethane resins having a thickness of 1 mm and a width of 1 mm.
However, in this embodiment, since toner accumulation is likely to occur at the end of each insulating coating material 52, it is preferable to take measures such as separating the insulating coating material 52 from the intermediate transfer belt 20 at a point outside the image area.
[0050]
Further, as the layer thickness adjusting blade 32, as shown in FIGS. 10 (b-1) to 10 (b-3), a plurality of insulating covering materials 52 are bonded and fixed to a conductive plate material 51. However, an inclined portion 521 is provided on at least the residual toner entry side of each of the insulating coating materials 52 so that toner accumulation does not occur.
Here, the inclined portion 521 includes both a flat shape and a curved shape.
According to this aspect, since the toner is less likely to accumulate due to the presence of the inclined portion 521, the degree of freedom of the contact / separation timing of the layer thickness adjusting blade 32 can be increased.
[0051]
As the layer thickness adjusting blade 32, as shown in FIGS. 10 (c-1) to (c-3), a plurality of insulating coating materials 52 are provided on a conductive plate material 51, and the insulating coating material 52 is provided. At least one portion between the two 52 is provided with a substantially V-shaped or U-shaped recess 522 in which the conductive member 51 is partially exposed.
According to this aspect, since the bias applying portion to which the thin layer bias VBH is applied is present in the concave portion 522 during the process of extending the residual toner with the plurality of insulating covering materials 52, The effect of extending the toner is further promoted.
[0052]
Further, as the layer thickness adjusting blade 32, as shown in FIG. 10 (d-1), a conductive convex portion 58 made of a conductive or semiconductive member is provided on the foremost side of the conductive plate member 51, and In some cases, one or more insulating covering materials 52 are provided separately from the conductive convex portions 58.
According to this aspect, the residual toner can be stretched by one or a plurality of insulating coating materials 52, and the residual toner can be directly charged via the conductive convex portions 58.
For this reason, the conductive convex portion 58 can perform a part of the function of the charge control roll 33, and accordingly, the charging performance of the charge control roll 33 can be more reliably realized.
If the charging performance by the conductive protrusions 58 is sufficiently ensured, the residual toner can be charged to a predetermined charged state only by the conductive protrusions 58 without using the charge control roll 33.
[0053]
◎ Embodiment 2
FIG. 11 is a schematic configuration diagram showing Embodiment 2 of the image forming apparatus according to the present invention. In the figure, the basic configuration of the image forming apparatus is substantially the same as that of the first embodiment, but differs from the first embodiment in that the elastic intermediate transfer belt 20 is used to transfer a toner image from the photosensitive drum 10. The photosensitive drum 10 contacts the photosensitive drum 10 at a predetermined contact area x along the shape of the photosensitive drum 10. Note that components similar to those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and detailed description thereof will be omitted.
In particular, in this example, the intermediate transfer belt 20 is stretched over four stretching rolls 21 to 24, and is disposed on the surface of the photosensitive drum 10 located between the rotary developing device 13 and the cleaning device 14. Along a predetermined contact area x, the contact area is closely arranged.
In this embodiment, the intermediate transfer belt 20 is not provided with an independent drive system. The intermediate transfer belt 20 uses the photosensitive drum 10 as a drive source, and contacts the photosensitive drum 10 via a contact area x. And is driven to rotate.
[0054]
Therefore, according to the present embodiment, the photosensitive drum 10 and the elastic intermediate transfer belt 20 are arranged in contact with each other in a relatively wide contact area x, and are elastically pressed by the elastic intermediate transfer belt 20. The tack surface pressure between the photosensitive drum 10 and the elastic intermediate transfer belt 20 is not so high, and the toner image is wrapped by the elastic intermediate transfer belt 20 so that the toner image on the photosensitive drum 10 is elastic. The primary transfer is performed on the intermediate transfer belt 20 side.
At this time, the image transferred to the elastic intermediate transfer belt 20 has no image quality defects such as holographic characters due to a large tack surface pressure, and is transferred with high transfer efficiency, so that the color image quality on the recording material is extremely excellent. Dripping.
[0055]
Further, in the present embodiment, in addition to simplifying the device configuration,
The cleaning members (the cleaning roll 31, the layer thickness adjusting blade 32, and the charging control roll 33) constituting the cleaning device 30 do not need to apply an excessive load to the intermediate transfer belt 20, and are independent of the intermediate transfer belt 20. Even if no drive system is provided, the intermediate transfer belt 20 is driven by the photosensitive drum 10 and is stably driven and rotated.
[0056]
◎ Embodiment 3
FIG. 12 shows a main part of an image forming apparatus according to a third embodiment of the present invention.
In the figure, the basic configuration of the image forming apparatus is substantially the same as that of the first embodiment, but is different from the first embodiment in that the layer thickness adjusting member 32 of the cleaning device 30 is a layer thickness adjusting roll. .
In the present embodiment, the layer thickness adjusting roll 32 includes a conductive roll main body 61, a semiconductive layer 62 as an inner layer in contact with the roll main body 61, and an insulating coating layer 63 as an outer layer.
As a specific example, for example, a mode in which a semiconductive rubber having a thickness of 2 mm is provided as an inner layer in contact with a SUS roll main body having a diameter of 8 mm, and a urethane rubber having a thickness of 0.2 mm is provided as an outer layer.
[0057]
Here, when the layer thickness adjusting roll 32 rotates with respect to the intermediate transfer belt 20, the effect of stretching the toner is reduced. Therefore, by fixing the rotating shaft by the shaft fixing mechanism, the layer thickness adjusting roll 32 does not rotate during the cleaning operation. It has become.
The layer thickness adjusting roll 32 is not limited to the non-rotating type, and may be configured to be driven to rotate at a speed having a speed difference from the moving speed of the intermediate transfer belt 20.
The surface properties of the layer thickness adjusting roll 32 may be roughened if necessary, or the surface layer may be formed of a material having a somewhat rough surface such as urethane foam rubber to promote the toner stretching effect. It may be.
[0058]
Further, a mechanism for periodically rotating the layer thickness adjusting roll 32 is provided so as to prevent the accumulation of toner on the same portion of the layer thickness adjusting roll 32, or the toner attached to the layer thickness adjusting roll 32 is cleaned. Therefore, it is preferable to add a function of applying a reverse bias and providing a cycle for returning the adhered toner to the intermediate transfer belt 20 side.
When such a function is added, the amount of accumulated toner can be reduced, and the device can be used for a longer time.
[0059]
◎ Embodiment 4
FIG. 13 shows a main part of an image forming apparatus according to a fourth embodiment of the present invention.
In the figure, the basic configuration of the image forming apparatus is substantially the same as that of the first embodiment, but is different from the first embodiment in that the layer thickness adjusting member 32 of the cleaning device 30 is a layer thickness adjusting brush. .
In this embodiment, the layer thickness adjusting brush 32 is obtained by implanting a brush material 72 on a conductive plate 71 as shown in FIG.
As the brush material 72 used in this example, a material in which the surface of the conductive brush material is coated with an insulating coating material, a material in which carbon is dispersed in the insulating brush material, or the like may be appropriately selected. It is necessary that the hair be implanted in a difficult manner.
[0060]
Here, as the layer thickness adjusting brush 32, for example, as shown in FIG. 14A, a brush material 72 may be arranged upright with respect to the conductive plate material 71, or as shown in FIG. The brush member 72 may be arranged in an inclined manner to reduce the load on the intermediate transfer belt 20.
Further, since the layer thickness adjusting brush 32 is not used for absorbing the residual toner, in order to reduce the load, as shown in FIGS. The charge of the toner can be reduced, and the residual toner can be stretched.
[0061]
◎ Embodiment 5
FIG. 15 shows a main part of an image forming apparatus according to a fifth embodiment of the present invention.
In the figure, the basic configuration of the image forming apparatus is substantially the same as that of the first embodiment, but is different from the first embodiment in that the layer thickness adjusting member 32 of the cleaning device 30 is a layer thickness adjusting pad. .
The layer thickness adjusting pad 32 has a conductive support plate 81 made of, for example, a bent leaf spring. A semiconductive member 82 is provided on the conductive support plate 81 and the surface of the semiconductive member 82 is provided. Is covered with an insulating covering material 83, and both ends of the conductive support plate 81 are detachably engaged with a locking receiving portion 84a of an insulating holder 84.
A bias VBH for a thin layer is applied to the conductive support plate 81, and the layer thickness adjustment pad 32 is arranged so as to be in contact with the intermediate transfer belt 20 with an appropriate pressing force.
[0062]
Also in this embodiment, the layer thickness adjusting pad 32 operates in substantially the same manner as in the first embodiment and the like, and adjusts the layer thickness of the residual toner to a reference thickness or less. The toner collecting operation can be reliably realized.
Further, in this embodiment, since the layer thickness adjusting pad 32 is configured to be detachable from the insulating holder 84, the replacement operation can be easily performed.
[0063]
◎ Embodiment 6
FIG. 16 shows a main part of an image forming apparatus according to a sixth embodiment of the present invention.
In the figure, the basic configuration of the image forming apparatus is substantially the same as that of the first embodiment, but is different from the first embodiment in that the layout of the charge control roll as the charge control member 33 of the cleaning device 30 is changed. It is.
That is, in the present embodiment, the charging control roll 33 is disposed at a portion of the intermediate transfer belt 20 that is located downstream of the tension roll 23 and upstream of the tension roll 21. A backup roll 91 is provided inside the opposed intermediate transfer belt 20, and a charging bias is applied to the charging control roll 33.
In this mode, the operation is substantially the same as in the first embodiment.
[0064]
◎ Embodiment 7
FIG. 17A illustrates a main part of an image forming apparatus according to a seventh embodiment of the present invention.
In the figure, the basic configuration of the image forming apparatus is substantially the same as that of the first embodiment, but is different from the first embodiment in that a layer thickness adjusting blade serving as a layer thickness adjusting member 32 of the cleaning device 30 is provided with a charge control member. 33 is also used.
17, the layer thickness adjusting blade 32 includes, for example, a conductive electrode material 102 and an insulating coating material 103 in order from the one end of the conductive plate material 101 in FIG. 17, and the conductive plate material 101 has a thin layer. The bias power supply 105 to which the application bias VBH (also used as the charging bias VBT) is applied is connected.
[0065]
According to the present embodiment, the layer thickness adjusting blade 32 charges the residual toner mainly through the conductive electrode material 102, and reduces the layer thickness of the residual toner to the reference thickness or less mainly through the insulating covering material 103. adjust.
For this reason, in the present embodiment, the residual toner that has passed through the layer thickness adjusting blade 32 is adjusted to have a thickness equal to or less than the reference thickness and has a predetermined charging characteristic. Is collected by a toner collecting member (not shown).
[0066]
【Example】
◎ Example 1
In this embodiment, as shown in FIG. 18A, the elastic intermediate transfer belt 20 (stretched by the stretching rolls 21 to 23) is arranged in contact with the photosensitive drum 10 so as to be in contact therewith. A layer thickness adjusting roll (a non-rotating metal roll is used in this example) serving as a layer thickness adjusting member 32 is disposed at a position facing the layer 21, and the thin layer bias VBH and the layer bias VBH applied to the layer thickness adjusting roll 32. The effect of elongating the residual toner T was evaluated by changing the pressing force of the thickness adjusting roll 32.
Here, as the pressing force, under the three-step conditions A to C (specifically, A: 0.15 mm, B: 0.1 mm, C: 0.05 mm bite amount) in which the load was sequentially reduced from the initial value. The bias VBH for the thin layer was changed with respect to “DC component (Vdc: +2.0 kV) + AC component (Vac: 2.0 kHz−Vpp2.5 kV)” and only the AC component.
In the figure, reference numeral 25 denotes a primary transfer roll, 26 denotes a secondary transfer roll, 40 denotes a recording material, and TZ denotes a toner image.
[0067]
The results are shown in FIG. In the figure, ◎, △, and Δ are relative evaluations of the effect of extending the residual toner T.
According to the figure, it is understood that the effect of extending the residual toner T can be sufficiently exhibited under the condition that the DC component is included as the thin layer bias VBH.
As for the pressing force, it is understood that the effect of extending the residual toner T is exhibited even if the load is reduced to some extent.
[0068]
◎ Example 2
In the present embodiment, in the model shown in FIG. 18A, only the DC component Vdc is given as the bias VBH for the thin layer, and the effect of extending the residual toner T is evaluated while changing the DC component Vdc.
The results are shown in FIG.
According to the figure, it is understood that the effect of extending the residual toner T sharply increases under the condition that the DC component Vdc exceeds a certain reference value.
[0069]
◎ Example 3
In this embodiment, the method of stretching the residual toner T is evaluated by changing the method of the layer thickness adjusting member 32.
In the present embodiment, a method using a layer thickness adjusting roll as the layer thickness adjusting member 32 (metal roll type) as shown in the model shown in FIG. 18A, and a layer thickness as shown in FIG. As the adjusting member 32, a blade (in this example, a mode in which a conductive blade is sandwiched between the intermediate transfer belt 20 and a pressing roll 32 '(using a layer thickness adjusting roll of the model of FIG. 18A)) is used. System (blade system).
In each system, "DC component (Vdc: +2.0 kV) + AC component (Vac: 2.0 kHz-Vpp 2.5 kV)" was used as the bias VBH for the thin layer on the metal roll.
[0070]
The results are shown in FIG. In the drawing, ◎ and ○ indicate relative evaluation of the effect of extending the residual toner T.
As shown in the figure, it was understood that the residual toner T can be uniformly thinned in the blade method as compared with the metal roll method, and the effect of extending the residual toner T is larger.
[0071]
【The invention's effect】
As described above, according to the cleaning device of the present invention, the cleaning device includes the cleaning roller that electrostatically collects the toner remaining on the belt-shaped member. Since a layer thickness adjusting member whose thickness is adjusted to be equal to or less than the reference thickness and a charge controlling member whose charge polarity and charge amount of the residual toner are controlled are provided, the state of the residual toner (the amount of the residual toner or the residual toner) is adjusted. ), The cleaning performance of the residual toner on the belt-shaped member can always be kept good.
Further, in the image forming apparatus using this cleaning device, the belt-shaped member can be kept clean at all times, so that it is possible to easily obtain an image of good quality at all times without image quality defects due to poor cleaning. it can.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing an outline of a cleaning device according to the present invention and an image forming apparatus using the same.
FIG. 2A is an explanatory diagram showing a state of residual toner after passing through a layer thickness adjusting member, and FIG. 2B is an explanatory diagram showing a state of residual toner when no layer thickness adjusting member is provided.
3A is an explanatory view showing a case where the residual toner is a thin layer and a state of collecting the residual toner after passing through a layer thickness adjusting member, and FIG. 3B is a diagram illustrating a case where the residual toner is a thick layer (without a layer thickness adjusting member); FIG. 4 is an explanatory diagram illustrating a state of collecting the residual toner in FIG.
FIG. 4 is an explanatory diagram illustrating the image forming apparatus according to the first embodiment;
FIG. 5 is an explanatory diagram showing details of a cleaning device used in the first embodiment.
FIGS. 6A to 6F are explanatory diagrams showing specific examples of the layer thickness adjusting member used in the first embodiment.
7A is an explanatory diagram illustrating a process of collecting the residual toner when the residual toner is a thin layer, and FIG. 7B is an explanatory diagram illustrating a process of collecting the residual toner when the residual toner is a thick layer.
FIG. 8 is an explanatory view schematically showing a layer thickness adjusting process of the layer thickness adjusting member used in the first embodiment.
FIGS. 9A and 9B are explanatory views showing a modification in which the layer thickness adjusting member in the first embodiment is separated into a plurality of components.
10 (a-1) to (d-1) are explanatory views showing other various modifications of the layer thickness adjusting member in the first embodiment.
FIG. 11 is an explanatory diagram illustrating an image forming apparatus according to a second embodiment.
FIG. 12 is an explanatory diagram illustrating an image forming apparatus according to a third embodiment.
FIG. 13 is an explanatory diagram illustrating an image forming apparatus according to a fourth embodiment.
FIGS. 14A to 14D are explanatory diagrams showing specific examples of the layer thickness adjusting member used in the fourth embodiment.
FIG. 15 is an explanatory diagram illustrating an image forming apparatus according to a fifth embodiment.
FIG. 16 is an explanatory diagram illustrating an image forming apparatus according to a sixth embodiment.
FIG. 17A is an explanatory diagram illustrating an image forming apparatus according to Embodiment 7, and FIG. 17B is an explanatory diagram illustrating details of a layer thickness adjustment charging control member.
FIGS. 18A and 18B are explanatory diagrams showing an experimental model used in the example.
FIG. 19A is an explanatory diagram showing a layer thickness adjustment evaluation based on a difference in a thin layer bias application pattern and a load pattern in the layer thickness adjustment member, and FIG. 19B is a drawing illustrating the effect of extending the residual toner layer in the layer thickness adjustment member. FIG. 19C is an explanatory diagram showing a relationship between the DC component of the bias for the thin layer and a DC component of the bias for the thin layer. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Belt-like member, 2 ... Transfer medium, 3 ... Transfer device, 4 ... Cleaning device, 5 ... Cleaning roll, 6 ... Layer thickness adjustment member, 6a ... Conductive member, 6b ... Insulating member, 7 ... Charging control member , T: residual toner, TZ: toner image, VBC: cleaning bias, VBH: thin layer bias, VBT: charging bias

Claims (11)

A cleaning device for cleaning toner remaining on the belt-shaped member,
A cleaning roll on which residual toner is electrostatically attracted,
A layer thickness adjustment member provided on the upstream side of the cleaning roll to stretch and adjust the residual toner layer to a reference thickness or less;
A cleaning device provided upstream of the cleaning roll and configured to control a charging polarity and a charging amount of the toner remaining on the belt-shaped member. The cleaning device according to claim 1,
The cleaning device, wherein the layer thickness adjusting member is disposed upstream of the charging control member. The cleaning device according to claim 1,
A cleaning apparatus characterized in that a bias for a thin layer is applied to a layer thickness adjusting member. The cleaning device according to claim 3,
A cleaning apparatus characterized in that the thin layer bias applied to the layer thickness adjusting member has at least a DC component. The cleaning device according to claim 3,
A cleaning apparatus characterized in that the thin layer bias applied to the layer thickness adjusting member has at least an AC component. The cleaning device according to claim 1,
The cleaning device according to claim 1, wherein the layer thickness adjusting member provides a frictional resistance between the belt-shaped member and the belt-like member such that the residual toner layer is stretched. The cleaning device according to claim 1,
A cleaning device, wherein the layer thickness adjusting member includes a conductive member and an insulating member, and the insulating member is arranged to face the residual toner layer on the belt-shaped member. The cleaning device according to claim 7,
A cleaning device, wherein a thin layer bias is applied to a conductive member of a layer thickness adjusting member. The cleaning device according to claim 7,
The cleaning device, wherein the layer thickness adjusting member is made of a member in which a conductive member and an insulating member are integrated, and at least a surface side of the conductive member is covered with the insulating member. The cleaning device according to claim 7,
A cleaning device, wherein the layer thickness adjusting member has a configuration capable of separating a conductive member and an insulating member, and the insulating member is replaceable. An image forming apparatus including a belt-shaped member on which a toner image is carried, a transfer device that transfers the toner image on the belt-shaped member to a transfer medium, and a cleaning device that cleans toner remaining on the belt-shaped member.
An image forming apparatus comprising the cleaning device according to claim 1 as a cleaning device.

Images